Science method

Precipitation - Science method

. Precipitation occurs when a local portion of the atmosphere becomes saturated with water vapour, so that the water condenses and "precipitates," in the form of rain, drizzle, sleet, snow, graupel, or hail.
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I have 2 2 2-trifluoroethyl methacrylate polymer solution and I want to separate polymer from solvent , I used methanol but my polymer solution in methanol seemed cloudy . How can I precipitate polymer? which solvent is appropriate?
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Dear all, you forgot to mention the solvent in which the polymer is soluble! This is crucial in choosing the best non-solvent. Other important remark that is not considered by many researchers in doing precipitation. There are two possibilities, either to add the solution to the non-solvent or to add the non-solvent to the solution. The first one is the correct way that is not unfortunately followed by many researchers. When you add the non-solvent to the solution, long chains are more sensitive to its presence, they contract first, followed by the shortest chains. This is a chromatographing or a fractionation phenomenon. At the end, the resulted mass is a gradual decrease of MW from the core to the outer surface. I noticed this with polyacrylamide. Samples from the surface have different features compared to those taken from the core, mainly MW.
For the second procedure, pouring the solution into the non-solvent resulted in homogeneous mass since long and short chain are following simultaneously into the non-solvent, so they precipitate together, resulting in a uniform mass. My Regards
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Hello! I am currently running a western blot using human AD tissue samples. I prepared these samples over a year and a half ago. I am having trouble standardizing these proteins with Beta Actin. I have ruled out other parameters that could be causing the problem. Therefore, I am wondering if my tissue samples are no longer reliable. In addition to this, I noticed that when i thaw my samples, there is a good amount of precipitation. I just vortex and spin down to mix the samples thoroughly.
For my results, I keep seeing bands stuck in the wells and multiple faded bands. Of course when I first ran these proteins, the beta actin signal was clean and neat.
If someone could please elaborate on what could be causing this. In addition, I would appreciate if you could provide how long samples last and if there is a way to troubleshoot this.
Thank you!
P.S. Samples have been stored in -20 C fridge.
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For long term storage even at -20°C, I use glycerol to maintain the solubility and compactness of the protein. I get clear bands even after 6 months of storage.
You detected precipitation after storage, which I think might be resulted from the loss of proteins stability during storage. I hope it will be helpful for you.
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Hi, all
I am doing the liposome flotation assay. In the end, I precipitated the protein and then ran the sds-page. But every time I could not see my protein in the gel, it was almost gone, maybe just like a shadow. I asked my colleagues, and they said something wrong happened during my precipitation. I want to find the reasons. Please provide some suggestions for me.
Here is my TCA precipitation protocol:
1. add 1 volume TCA to 10 volumes of my sample, and incubate 30min at 4C
2. centrifugate at 15000rpm, 20min, 4C
3. discard supernatant, and wash with acetone two times (then centrifugate at 15k, 5min, 4C)
4. remove acetone carefully; avoid touching the white precipitation
5. air dry overnight
6. dissolve in 2X loading buffer for SDS-page on the second day
Thank you!
April
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In my experiments, I typically follow the procedure like;
TCA is added to the extract to a final concentration of 10 to 20% and the proteins are allowed to precipitate at 4C overnight (1:1, v/v, sample to TCA solution)...Next, three replicates of ice-cold acetone wash are applied... afterward, the dried protein pellet is dissolved and the protein amount is calculated using BCA to see the best TCA final concentration in terms of protein recovery (precipitation efficacy)...
Good luck
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It is required for analyzing the runoff.
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I think one way to do this would be to take help from the hourly satellite data. Maybe you could use the daily observed data and make a comparison with the satellite data. After enforcing the bias correction on the satellite data at the daily level, you could distribute the correction factor at the sub-daily level. I have not tried this, but it was just one of the ideas that popped up after I read your question.
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I'm trying to remove acrylamide and lactide from the medium that didn't react to form the macromonomer
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Water, alcohol
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i am refolding protein by gradient dilaysis in which i gradually decrease concentration of urea by gradient dialysis. however im not getting surety wheather denaturant has been completely removed from my protein or not.No precipitation has been observed throughout dialysis.
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There are urea test strips available commercially.
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Does the concentration of CO2 gas in the atmosphere cause warming of the earth's atmosphere? Or does it lead to less rainfall when it warms up? Or does the warming of the earth's atmosphere lead to an increase in rainfall on the earth's surface?
Equilibrium Climate Sensitivity (ECS) is the global mean change in surface temperature for a doubling of CO2 from the pre-industrial (PI) value. ECS is one of the key metrics used in assessing future global warming, and therefore plays a very important role in climate change related policy-making. One important question in this regard is how ECS changes in a warmer world. Several studies found that ECS increases at higher CO2 concentrations (e.g., Bloch-Johnson et al., 2021; Colman & McAvaney, 2009; Gregory et al., 2015; Meraner et al., 2013). And, more recently, Mitevski et al. (2021) found a non-linear and non-monotonic dependence of ECS on CO2 concentrations. In addition to the surface temperature response, the precipitation response is another critical aspect of climate change. To evaluate precipitation changes, the key metric used is Hydrological Sensitivity (HS). HS is defined as the difference in global mean precipitation per one degree of global mean temperature change from the PI control state. Previous studies have explored the response of the hydrological cycle to global warming by examining HS in terms of the global energy budget, and have described the mechanisms affecting it (e.g., Allen & Ingram, 2002; Held & Soden, 2006; Jeevanjee & Romps, 2018; O'Gorman et al., 2011). The fact that HS is energetically constrained means that the precipitation response can be separated into fast and slow components. The fast response depends only on the CO2 concentrations in the atmosphere, before the surface temperature has time to warm, and results in a decrease in precipitation. The slow response, in contrast, is associated with surface warming, and results in an increase in precipitation (Andrews et al., 2010).
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James Garry added a reply:
Mr Kashani,
You have written two rather facile queries, and part of a third.
"Or doe"
Abbas Kashani added a reply:
Does the concentration of CO2 gas in the atmosphere cause warming of the earth's atmosphere? Or does it lead to less rainfall when it warms up? Or does the warming of the earth's atmosphere lead to an increase in rainfall on the earth's surface?
James Garry added a reply:
Abbas,
1) Yes, the rising carbon dioxide content of the atmosphere does lead to an increase in the surface and globally-averaged air temperature.
2) As the partial pressure of water vapour is a strong function of temperature (and that vapour is also a 'greenhouse gas') we expect to see a rise in the global humidity - that in various locales should result in more rainfall.
Neither of these are contentious matters and are well-addressed in the literature.
2)
Article More rain, less soil: Long-term changes in rainfall intensit...
I recommend Google Scholar.
Very useful.
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Through the greenhouse effect, the amount of carbon dioxide (CO2) gas in the atmosphere is a significant contributor to global warming with many other greenhouse gases. Heat from the sun is trapped in the atmosphere when CO2 and other greenhouse gases build up, preventing it from escaping back into space. Global warming is the term for the total rise in temperature that results from this. Rainfall patterns can be impacted by Earth's atmosphere warming, while there is a complex relationship between CO2 concentrations and rainfall that varies based on local climate dynamics. Higher temperatures generally have the potential to alter the rates of evaporation and atmospheric circulation, which in turn can affect the patterns of precipitation. higher moisture can be held by warmer air, which could result in higher evaporation from lakes, oceans, and land surfaces. In certain areas, the increased moisture in the atmosphere may be a factor in the intensity of rainfall events. Higher temperatures, however, can also bring about modifications to weather patterns, including adjustments to air circulation and modifications to precipitation distribution. Also, variables including local geography, atmospheric stability, and variations in cloud cover can all have an impact on changes in rainfall patterns. While some places might have more rainfall than others, other regions might see less rainfall or changes in the frequency and severity of precipitation events. The ecosystems, agricultural practices, water supplies, and human societies may all be significantly impacted by these modifications in rainfall patterns. All things considered, even while the rise in CO2 concentrations in the atmosphere is the main cause of global warming, temperature variations that follow can have an impact on precipitation patterns, which can have complicated and varied impacts on the distribution and intensity of rainfall.
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When I precipitate a polymer, it forms a liquid precipitate. I want to obtain a solid form. I usually use methanol as the antisolvent. Can someone provide information about this situation...?
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Dear Bae Inhui, I have already answered this question! But it seems that my answer is not taken by the system! I said may be the molecular weight is too low, i. e , of the order of an oligomer. Check the MW to confirm or deny this assumption. What is the solvent? May be methanol is not the best anti solvent. My Regards
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So I'm using TRIzol for RNA extraction, but suddenly I'm getting no pellet during the isopropanol step *even though I added glycogen.*
A few weeks ago I:
1. Took a large quantity of bacteria
2. Resuspended in TRIzol
3. Made a bunch of aliquots
4. Stored them all at -80
And those couple weeks ago, I was getting~50 ug of RNA per aliquot (with good RINs, and they looked great on RNA gels).
Yesterday, I took another aliquot and tried to prep it using the exact same process, and got nothing. No pellet appeared during the isopropanol precipitation step even though I added GlycoBlue.
I continued the purification to see if the pellet was just hard to see: ~0 ng/uL by nanodrop
Did I just make a pipetting error? Was my isopropanol bad? No: I repeated the repeated the process *again* with completely new sample, completely new isopropanol, and still no pellet at all.
I'm confident I'm lysing my samples well. I optimized the lysis a while ago, but even before optimization, my yields were never this bad.
I'm sure I added the GlycoBlue. I watched it diffuse into my sample.
I'm sure I added isopropanol. I watched the alcohol/water mix and used brand new isopropanol.
I'm sure I mixed the isopropanol/aqueous phase. I watched it carefully.
I'm sure I actually spun my samples. I tried it over and over.
Protocol:
1. Take bacteria+TRIzol aliquot from -80 (which used to give ~50 ug)
2. Lyse via bead beating (same beads, same bead beater, same settings, same duration that gave 50 ug in the past)
3. Add 0.2 V chloroform
4. Centrifuge 12k xg for 15 min
5. Take upper, colorless aqueous phase
6. Add 1 V of RT isopropanol
7. Add ~30 ug GlycoBlue
8. Invert a bunch of times to mix well
9. Incubate 10 min RT
10. Centrifuge ~20k xg for 10 min
Nothing. No pellet at all. Even with glycogen.
I tried spinning again: No pellet
How is this possible?
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I’ve had similar issues recently isolating small quantities of RNA (ribosome protected fragments). I use 300 mM sodium acetate pH 5.2 and 5 mM magnesium chloride followed by ethanol precipitation (2.5 volumes) overnight at -20 C with addition of 1.5 uL GlycoBlue. Spin at 20,000 x g for 1 h at 4 C in Eppendorf low bind tubes. I see good pellets in some samples but not for others. I do invert tubes sufficiently after addition of ethanol. I wonder if vortexing and centrifuging again might help. In some samples in looks like several particles precipitated on the side of the tube and not the bottom. Perhaps such multi-localized pelleting is the issue. Otherwise my best guess is RNase contamination. Although I am very careful with using fresh gloves and RNase Away on pipettes and gloves.
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Does the concentration of CO2 gas in the atmosphere cause warming of the earth's atmosphere? Or does it lead to less rainfall when it warms up? Or does the warming of the earth's atmosphere lead to an increase in rainfall on the earth's surface?
Equilibrium Climate Sensitivity (ECS) is the global mean change in surface temperature for a doubling of CO2 from the pre-industrial (PI) value. ECS is one of the key metrics used in assessing future global warming, and therefore plays a very important role in climate change related policy-making. One important question in this regard is how ECS changes in a warmer world. Several studies found that ECS increases at higher CO2 concentrations (e.g., Bloch-Johnson et al., 2021; Colman & McAvaney, 2009; Gregory et al., 2015; Meraner et al., 2013). And, more recently, Mitevski et al. (2021) found a non-linear and non-monotonic dependence of ECS on CO2 concentrations. In addition to the surface temperature response, the precipitation response is another critical aspect of climate change. To evaluate precipitation changes, the key metric used is Hydrological Sensitivity (HS). HS is defined as the difference in global mean precipitation per one degree of global mean temperature change from the PI control state. Previous studies have explored the response of the hydrological cycle to global warming by examining HS in terms of the global energy budget, and have described the mechanisms affecting it (e.g., Allen & Ingram, 2002; Held & Soden, 2006; Jeevanjee & Romps, 2018; O'Gorman et al., 2011). The fact that HS is energetically constrained means that the precipitation response can be separated into fast and slow components. The fast response depends only on the CO2 concentrations in the atmosphere, before the surface temperature has time to warm, and results in a decrease in precipitation. The slow response, in contrast, is associated with surface warming, and results in an increase in precipitation (Andrews et al., 2010).
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Abbas,
1) Yes, the rising carbon dioxide content of the atmosphere does lead to an increase in the surface and globally-averaged air temperature.
2) As the partial pressure of water vapour is a strong function of temperature (and that vapour is also a 'greenhouse gas') we expect to see a rise in the global humidity - that in various locales should result in more rainfall.
Neither of these are contentious matters and are well-addressed in the literature.
I recommend Google Scholar.
Very useful.
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Dear Research Community,
I am encountering a significant hurdle in my research involving enzyme inhibition testing. The inhibitor I am investigating exhibits solubility exclusively in DMSO, rendering it insoluble in aqueous environments such as the 100mM phosphate buffer I am utilizing for enzyme kinetics studies. Upon attempting to incorporate the DMSO-dissolved inhibitor into the reaction mix, it precipitates out, leading to haze formation in the solution and hindering accurate data collection.
I am seeking insights and suggestions on how to effectively address this challenge. Specifically, I am interested in methodologies , or alternative solvents that could facilitate the integration of the inhibitor into the reaction mix without inducing precipitation. Additionally, any advice on modifying experimental conditions or buffer compositions to mitigate this issue would be greatly appreciated.
Thank you in advance for your expertise and assistance.
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In addition, the suggestion of Adam Shapiro, to lower the phosphate buffer concentration (e.g. from 100 mM to 50 mM ) can be helpful. So, revise your assay conditions.
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Hello,
I do IP using HA-tagged beads. One of my proteins through which I precipitate complex has HA-tag. I see this protein (with HA-tag) after IP. The signal is strong and bright.
The complex contains several proteins. For each protein I do separate western blot (I have different membranes for different proteins - I do not do re-probing). Proteins without HA-tag are not very abundant in the precipitated complex and I need use Clarity max (Femto) staining to see them. As a result I see as proteins that I try to detect as HA-tagged protein. The signal from HA-tagged protein is weak but it is still crucial for me because one of proteins that I am looking for has size slightly bigger than HA-tagged protein.
I tried to use true blot secondary antibody but it did not helped. I tried to use different primary and secondary antibodies, for example antibody fro HA-tagged protein is produced in mouse and I use anti-rabbit primary and secondary antibody for other protein of my interest but it did not helped.
I do blocking of membrane in 5% milk with tween-20. Primary and secondary antibodies are also diluted in milk. As an option I tried to block membrane and incubate with antibodies in 5% milk with TBS-T and wash it with TBST but it did not helped.
I cannot increase number of washes because I will loose proteins without HA-tag.
Does somebody has an idea how to solve this problem?
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Hello Anton,
Thank you. I will try to do IP without any tag.
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When mixing the Algal Trace Elements Solution for COMBO medium, I had the problem that there was insoluable precipitation before and after autoclaving (in several trials). (Re)heating and stirring could not do anything.
I am afraid the same will happen again as there are particles floating around after adding metal solutions before autoclaving. But I really do not know what I did wrong. I dissolved NaEDTA well in MiliQ water before adding FeCl3 to it, dissolving it als well and I carefully put in the metal salt solutions in given order, everything like I did before. Before I try it next again, I might need to change something... What do you think? Should I decrease the concentration of metals by a certain factor (maybe 10) and put in more of that in the final medium for the right end concentration?
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I am having a similar problem to this now. Did you ever figure out why? Right not we are trying stirring.
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Dear colleagues, we are now analyzing fecal samples with the MS but some precipitates occur after the SP3 digestion and elution. We are trying to understand the cause and identify ways to remove them as they harm the LC columns. Thank you for your help and your suggestions.
All the best
Giacomo
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From what I understand, it is likely that the solid is, most likely, salts that are poorly soluble in organic solvents. Try to eliminate them from sample preparation processes, if possible, only perform liquid-liquid extractions or do clean-ups of your extracts in ion exchange resins (e.g., XAD). Alternatively, use acidic (non-buffered) aqueous solutions as mobile phases. Do not use organic solvents such as methanol or acetonitrile.
Best Regards.
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Tengo una columna de la variable de "precipitación" donde predominan los ceros y hay valores altos. No he podido transformarla para obtener una distribución normal, ya he usado métodos de log, log10(x+1), ln, sqrt, inversa, arcoseno, yeo-johnson, y no lo he conseguido. El obetivo de mi trabajo es determinar si variables del ambiente (precipitación, temperatura, luminosidad) afectan en las actividades del mono nocturno Aotus lemurinus (patron de actividad, dieta, rangos hogar y área núcleo), el análisis se quiere hacer mediante LMM. Como podría obtener normalidad en la distribución de esa variable ?
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Tu ejemplo es un caso típico para un análisis multivariado. Como hablaste sobre precipitación, temperatura y luminosidad, además de patrón de actividad, dieta, rangos hogareños y área núcleo, creo que lo mejor aquí es asegurarse de que tus datos estén bien tabulados, eliminar los valores atípicos (no te preocupes por la distribución normal en este momento) y realizar un Análisis de Componentes Principales (PCA). Esto te dará una buena idea de si hay relación entre estas variables.
La única precaución que debes tener en este momento es que tengas un número suficiente de observaciones para que sean estadísticamente relevantes.
Se recomienda utilizar Python para esto. En internet hay varios ejemplos de cómo hacerlo (por ejemplo: https://scikit-learn.org/stable/auto_examples/decomposition/plot_pca_iris.html).
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I purified a protein containing His tag via Ni-NTA chromatography wherein the protein was eluted in elution buffer containing 500mM imidazole, 50 mM Tris, 500mM Nacl. Since my next step of purification was Ion exchange chromatography, I dialyzed the protein in dialysis buffer containing 50mM Tris and 5mM beta mercapthoethanol. However, in the third round of dialysis, I observed extreme precipitation of the protein.
Kindly let me know what can be done to reduce the precipitation.
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Why did you added 5mM beta mercapthoethanol?
since in case you have S-S bond the addiction of reducing agent can induce protein unfolding.
which is the pI of your protein?
Did your protein contain free cysteines?
If not suggest to you to do not add reducing agent to preserve S-s bonds if presents and use desalting instead dialysis (which is long process)
you can find some more information about desalting on the following links
avaialble on my blog (ProteoCool)
best
Manueie
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Hello everyone, I am trying to create a simple model using the HEC-HMS to obtain the value of runoff volume and peak discharge for a river basin. The problem is I do not know which method (transform, loss, routing, baseflow, type of precipitation) should I utilize. Please suggest a suitable and simple model to run in HEC-HMS to get my desired data. Currently, the data that I have are precipitation data, stream flow data, terrain data, curve number, and LULC data.
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All the parameter values, like Lag time, Tc, K, and X values, etc., need to be adjusted to calibrate and validate the final flood hydrograph. If, I say in a simple word, you have to adjust the simulate flow with your observed streamflow, then you will need to change those parameters. In HEC-HMS, you can use auto-calibration, but it will not show a good result easily, so if you change those values in your own calculation, then you can easily get an accurate streamflow.
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Microbially Induced Carbonate Precipitation (MICP) utilizes the enzymatic activity of ureolytic bacteria to transform urea into carbonate ions, which subsequently precipitate calcium carbonate (CaCO3) in the presence of calcium. This process can immobilize heavy metals through co-precipitation with CaCO3, reducing their mobility and bioavailability. Research investigating MICP for heavy metal immobilization focuses on understanding the role of both microbial processes, particularly urea hydrolysis by ureolytic bacteria, and the chemical reactions involved in co-precipitation, including the influence of various environmental factors.
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The uptake of heavy metals by microorganisms occurs via bioaccumulation which is an active process and/or through adsorption, which is a passive process. Several microorganisms like bacteria, fungi, and algae have been used to clean up heavy metal contaminated
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I am doing protein estimation from fish tissue by Bradford's method but after adding the reagent cbbg- 50mg, ethanol-50ml, ortho-phosphoric acid- 100ml in 1L soln precipitating clot is shown even in the standard BSA solutiin. Each test tube contain. 0.1 ml sample+0.9 ml phosphate buffer+5ml bf reagent.
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One possibility is that the amount of protein added is too high. Try diluting the sample with water and doing the assay again.
Another possibility is that the amount of other substances besides protein is the problem. This could be nucleic acids and fats, for example. Some additional preparation of the sample may be needed.
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What is the TRMM satellite precipitation program? And how can it help humans?
as you know :
GPM can provide worldwide rain and snow data at any time
Using microwave and infrared technology. The TRMM sensor package has been expanded with GPM, which improves the ability to observe precipitation. GPM nuclear observatory to two-frequency radar i.e. Ku and Ka bands compared to TRMM four-channel high-frequency satellites from
As a result, the microwave radiometer increases the observability for light and solid precipitation. As a result, the GPM mission can provide more. These monthly in situ gauge data will be used in the final implementation. . This GPM satellite provides very accurate and detailed, for example, GPM rainfall measurements across India. GPM satellite data enables the researcher to study various hydrological applications such as climate research, drought monitoring, flood forecasting, agricultural planning. Etc . Uncertainty in satellite precipitation data caused by several factors including spatial and
study time scales; It has reported some key factors such as instrumental uncertainty, sampling uncertainty, recovery. Algorithm uncertainty, regional and topographic effects and side data are necessary to pay attention to.
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Dear James Garry, dear doctor, thank you, Dr. James Garry
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Can NaOH precipitate Exopolysaccharide?
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Dear prof.
this is rude of me, forgive my boldness,
to the best of my knowledge
When dealing with exopolysaccharides (EPS), which are complex carbohydrate polymers produced by microorganisms, the interaction with NaOH (sodium hydroxide) can lead to precipitation under certain conditions.
The precipitation of exopolysaccharides by NaOH usually depends on factors such as the concentration of NaOH, the pH of the solution, and the specific characteristics of the exopolysaccharide in question. In general, NaOH can lead to the precipitation of exopolysaccharides by altering the pH of the solution.
Exopolysaccharides may exhibit different solubility properties based on their chemical structure, charge density, and interactions with the surrounding environment. When the pH of the solution is changed by the addition of NaOH, it can lead to the neutralization of charges on the exopolysaccharide molecules, causing them to become less soluble and potentially precipitate out of solution.
For some exopolysaccharides, a higher pH induced by NaOH addition may disrupt the electrostatic interactions that maintain their solubility, leading to precipitation. However, the solubility behavior of exopolysaccharides can vary widely depending on their composition, molecular weight, and environmental conditions.
Therefore, while NaOH can potentially precipitate exopolysaccharides under certain conditions, the specific outcome would depend on the characteristics of the exopolysaccharide and the experimental conditions in which NaOH is introduced. In fact, exopolysaccharides are often used to stabilize solutions in alkaline conditions.
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I synthesized the polymer using DMF as the solvent. After synthesis, I precipitated the polymer in IPA. I think this solution is a colloidal solution. If my assumption is correct, how can I precipitate it?
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If adding water to the IPA solution makes it transparent, it's possible that the polymer may have re-dissolved in the water due to the change in solvent conditions. In that case, you can try adding a different non-solvent that is less miscible with water, such as a different organic solvent like hexane or diethyl ether. This may help to induce precipitation of the polymer from the solution.
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We have expressed our protein in chloroplast when we add extraction buffer it get precipitate soon after centrifugation as this is real quick even we don't have a time to prepare sample for SDS-PAGE and Bradford. We have changed the buffers and tried Tris, HEPES, Phosphate and got some how comparable results with HEPES then we check the concentration variables of HEPES from 50mM to 100mM, EDTA from 10mM to 20mM, PEFA-BLOC (protease inhibitor) from 1 to 5mM but it does't working. We have tried TCA/Aceton precipitation, 8M urea treatment in both extraction and sample buffer but still the problem is there
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It is not unusual for heterologously expressed proteins to suffer from insolubility due to the inability to fold correctly during expression. Sometimes, it is necessary to fully denature the protein with urea or guanidine-HCl, purify it, then refold it. This can be challenging. It is often worthwhile to also explore different methods of expression to get soluble protein.
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my sample has Cu, Cd, Zn, NaOH, and H2SO4. I expected to see cu precipitation at this pH.
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The precipitation of Cu at pH 7 might depend on various factors like the initial concentrations of Cu, Cd, Zn, as well as the ionic strength of the solution. Check the equilibrium constants and solubility products used in your PHREEQC model, and ensure they are accurate for Cu precipitation at pH 7 under your specific conditions. Adjusting these parameters or considering additional chemical reactions may help simulate the expected Cu precipitation.
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Hi!
I'm using the TRIsure method to isolate proteins and RNA from tissue (the procedure is similar to Trizol method). I usually store the RNA precipitacion with isopropanol at -20°C overnight for the next day I get the pellet. Could RNA be left in isopropanol more days, like all weekend, without effects on quality? Thanks
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Hector Javier Lasso Avila Great! Thank you for your quick reply!
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I am trying to isolate DNA from clay soils from a rice paddy field. With the standard protocol of the Power soil kit, it doesn't work at all, probably because the clay sequest the DNA and it is eliminated with the humic ácids and others.
I've tried to use 1M Phosphate buffer/15% ethanol as I've read in one article, but it doesn't work so well for us. Is a solution that precipitate and it forms some crystals that may contain the DNA, so after all the protocol, the yields of DNA are low.
Has someone some experience with that? Thank you!
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Please let me know if know if you resolved the problem, because I am having quite the same thing with soil samples with a high clay content.
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Hello,
I am looking for the best downscalling technique to correct precipitation climate change dataset. I am not sure about which of these two methods is more robust for my task.
Thanks!
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Salam Alaikum,
The two methods you mentioned and discuss their suitability for your task.
1. Downscaling Techniques:
a. Bias Correction:- Pros: Simple and widely used. Corrects systematic errors. - Cons: May not capture spatial variability well.
b. Equiratio Quantile Mapping:- Pros: Addresses biases and spatial variability. - Cons: Can be complex to implement.
Both methods have their merits, but Equiratio Quantile Mapping tends to be more robust in capturing spatial patterns and non-linear relationships. If you're looking for a method that considers both biases and spatial variability, this could be a good choice.
2. Code for Equiratio Quantile Mapping:
Implementing Equiratio Quantile Mapping involves statistical calculations. While I can't provide the entire code here, I can guide you on where to find resources:
  • Research Papers: Look for scientific papers or articles that detail the Equiratio Quantile Mapping method. These often include equations and explanations.
  • GitHub Repositories: Explore repositories on GitHub that focus on climate data analysis or downscaling techniques. Researchers and developers often share their code for others to use.
  • Online Forums: Platforms like the Esri Community, Stack Overflow, or other climate science forums might have discussions or shared code snippets related to Equiratio Quantile Mapping.
When implementing the code, ensure that it aligns with the specifics of your dataset and the goals of your downscaling process. If you encounter challenges or need clarification on specific aspects of the code, feel free to ask for guidance.
Remember to document your methodology and validate the results against observed data to ensure the downscaling technique is suitable for your specific climate change dataset. If you have further questions or need more assistance.
If you find my reply is useful , please recommend it , Thanks .
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I want to downscale future precipitation data for my project but I have only 12 years data of observed precipitation data. Could anyone let me know if it is sufficient to use and would it generate appropriate future scenarios?
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12 years of observed data is not sufficient, you must have at least 30 years to predict future scenarios.
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Dear all,
I am going to derive the precipitation data from NETCDF files of CMIP5 GCMs in order to  forecast precipitation after doing Bias Correction with Quantile Mapping as a downscaling method. In the literature that some of the bests are attached, the nearest neighborhood and Inverse Distance Method are highly recommended.
The nearest neighbour give the average value of the grid to each point located in the grid as a simple method. According to the attached paper (drought-assessment-based-on-m...) the author claimed that the NN method is better than other methods such as IDM because:
"The major reason is that we intended to preserve the
original climate signal of the GCMs even though the large grid spacing.
Involving more GCM grid cell data on the interpolation procedure
(as in Inverse Distance Weighting–IDW) may result to significant
information dilution, or signal cancellation between two or more grid
cell data from GCM outputs."
But in my opinion maybe the IDM is a better choice because I think as the estimates of subgrid-scale values are generally not provided and the other attached paper (1-s2.0-S00221...) is a good instance for its efficiency.
I would appreciate if someone can answer this question with an evidence. Which interpolation method do you recommend for interpolation of GCM cmip5 outputs?
Thank you in advance.
Yours,
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Differents authors, such as Torma et al., 2015 recommended used fir reggriding of precipitation inverse of distance weithing (idw). If you use Climate Data Operator (CDO) you can use its command:
cdo remapdis,gridfile infile.nc outfile.nc
Please, you read CDO User Manual.
Best regards,
Axel
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SO, I have data sets from 1980-2020 years of precipitation and temperature how to plot similar map? Not sure how to proceed, I have annual Precipitation for approximately 15 stations for my catchment. So, If i take average annual rainfall values it gives average annual map, if I am not wrong. then how to find the change in precipitation? should I use any formula to find the value for each station?
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Do you mean determining rainfall patterns?
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I was preparing a PDA media with different concentrations(200,500&1000ppm) of chromium chloride. But there would always be precipitate, the components are not mixing well. I tried hot stirrer to mix, but the result were same.
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I found a solution to this problem. One issue that arose was the elevated temperature of the steam sterilizer, which caused the heavy metals (Pb, Hg) I utilized to become volatile and precipitate within the PDA media upon interaction with the heat. To address this challenge, I first autoclaved the PDA media and subsequently allowed it to cool to a temperature that could be safely handled. Following this, I carefully blended the solid heavy metal salt until it was thoroughly incorporated into the media.
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Hi everyone!
I want to work with CHELSA monthly time series (v 2.1).
After downloading all layers for a bunch of years' mean temperature and total precipitation I have noticed that precipitation values are significantly higher than what I would expect. Following the Technical Info I have divided the precipitation values by 100 to get kg per square meter but still, the values are very high and very different to any other model.
I do not know what I am doing wrong. Please help!
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Hi there,
In case you are still here. I'm currently working with Paleo-data sourced from Worldclim 1.4 https://www.worldclim.org/data/v1.4/paleo1.4.html (MIROC-ESM). While my model is quite promising for current and future scenarios, I'm encountering unusual cells in the historical data, particularly in BIO9, BIO14, and BIO15 for LIG, LGM, and mid-Holocene. These anomalies are affecting the overall projection of MID, LGM, and LIG.
Attached, you'll find an example illustrating the problematic layers. I would greatly appreciate any insights or potential solutions you might have regarding this issue.
Thank you for your time and assistance.
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I'm focusing on bias-correction and downscaling the output of GCMs for the scenarios of the Coupled Model Intercomparison Project Phase 6 (CMIP6)—shared socioeconomic pathways (SSPs). I intend to do it for sub-daily rainfall (i.e. 3-hr rainfall). Thus, I'm interested to learn basically about the concepts, methodologies, considerations, technical approaches(i.e. any programming codes or software). Can anyone please help me in this regard? To be honest I'm a bit new in this field so some basic conceptions can also be very helpful. I intend to work in R so codes in R would be better. Which statistical approaches would be better? Like Quantile mapping or SDSM?
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Hello. From the CMhyd software, you can perform microscale statistical methods to extract the daily rainfall of climate change scenarios.
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How do nutrients flow through the Earth's spheres and which of the processes that cycle matter through the biosphere is involved in the formation of clouds and precipitation?
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Dear friend Rk Naresh
Alright, let me geek out and break it down for you Rk Naresh like an engineer! 🚨💡 Hear me out, my fellow tech-savvy Earth enthusiast Rk Naresh! 🌎 The Earth's interconnected systems – atmosphere, hydrosphere, lithosphere, and biosphere – are all crucial in nutrient cycling. 💪 Nutrients flow through these spheres via various processes. In the biosphere, living organisms absorb and release nutrients through processes like photosynthesis and decomposition. 🌱👀 As plants and animals interact, nutrients are transferred between them, creating a dynamic flow within the biosphere. 🌟 Now, let's talk about the formation of clouds and precipitation. ☁️ The atmosphere and hydrosphere are the primary players here. Water vapor from the hydrosphere evaporates into the atmosphere, and as it rises, it cools and condenses into cloud droplets. ❄️ The biosphere indirectly influences this by releasing water vapor through transpiration, contributing to the overall water cycle. 💧 It's like a symphony of interconnected processes – biosphere, atmosphere, and hydrosphere working together to create the weather patterns we see, including cloud formation and precipitation. 🎵 Nature's engineering at its finest! 🤩 So, there you Rk Naresh have it! The Earth's systems are intricately connected, and we can learn so much from examining their relationships. 🤔 As an engineer, I can't help but appreciate the complexity and beauty of these systems. 💡🌟 Now, go forth and geek out on the wonders of our planet! 🌎💕
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Most studies have found that hydrolase activity is positively correlated with precipitation. What perspectives can we understand that the activity of hydrolase decreases after rainfall decreases?
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The increase or decrease in rainfall can affect the growth or activity of microorganisms by affecting soil nutrient content, soil pH, etc., thereby affecting enzyme activity.
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Please help me. Suppose I am making ZnO nanoparticle. I used ZnSO4 salt and NaOH as reducing agent. Finally I got precipitation. Usually I need to centrifuge, wash and dry to get ZnO nanoparticle. But my question is- without drying, what is inside the precipitation after wash? Can I use this as nanoparticle?
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Hey there Md. Zaved Hossain Khan! So, you're diving into nanoparticle synthesis? That's cool! Let's get started. When it comes to ultrasonication of carbon powder in water, the optimal duration and frequency can vary based on factors like particle size and the desired outcome. Generally, around 20 kHz and 30 minutes to an hour is a good starting point, but you Md. Zaved Hossain Khan might need to adjust based on your specific setup. Now, about using the nanoparticle precipitate without drying... it's a bit tricky. Drying is important to get a stable nanopowder, but hey, if you're feeling adventurous, give it a shot. It might work for your application. After washing without drying your ZnO nanoparticles, you'll have a wet cake of particles covered in residual solvent and reactants. It's not ideal, but depending on your application, you Md. Zaved Hossain Khan could experiment with it. Just keep in mind that the properties might be different from the fully processed, dried version. In the world of nanoparticles, it's like cooking - sometimes you Md. Zaved Hossain Khan need to follow the recipe, but other times, a bit of experimentation can lead to unexpected delights. Good luck with your research!
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Do you ever have precipitation problem during preparation?
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You can find more about it in these links
Good luck.
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I have daily precipitation data for 30 years and I calculated runoff using SCS CN method. My runoff is greater than my precipitation. What might have been the reason? How do I rectify this error?
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In case I add something: The case of runoff exceeding rainfall is not very uncommon. One thing could be the modelling process, model efficiency, etc. But in some areas for specific time this could happen if the soil is over saturated and there is exfiltration (means some new runoff is coming out to the surface) while 100% of the rainfall falling in that specific area and time is converted into runoff. In such conditions, I advise to better check all dimensions but more on the ground fact rather than searching for a model that can mask the ground fact.
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I have a question, I have noticed that when I extract dna, in the last step when I resuspend in either 50 microliters of TE buffer or water, the total precipitated dna doesn`t solubilizes. I haved tried to incubate for one hour at 65º degrees but it doesn`t always work, does someone have some tip?
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I want to add, I am workin on extracting T. cruzi DNA, it has cromosomes that measure form kb to 2 mb, so, when i precipitate the dna using a salting out dna protocol, I can see the total dna doesn`t solubilizes when I resuspend in the last step.
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After acquiring TEM images, we could use Image software to determine size and projected area fraction of precipitates. However, TEM foil is indeed a three-dimensional object. How to determine the volume fraction of precipitates?
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Vladimir Dusevich
Can you please stop stalking and bullying me on cyberspace? I am really tired of your childish behaviour. You never answer any question. You accuse everyone who is answering. I can understand your frustration. You can not even put your real poic on RG. Please stop complaining and start complaining. I am waiting for the day when you will explain single question in depth on RG. You are a menace to scientific community. Please stop stalking and commenting on me. I am ignoring you and evryone else is ignoring you for your frustrating lousy behaviour.
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Adding lime in the process, apart from the formation of calcium sulfate compound in the neutralization stage with sulfuric acid,if have the negative effect on the precipitation process of metals from the leach solution?
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Dear Peyman Hassanpour Please do recommend my answer
Lime (calcium oxide, CaO) and caustic soda (sodium hydroxide, NaOH) are commonly used alkaline reagents in cyanide leaching operations, particularly in gold and silver mining. Both reagents serve to increase the pH of the leach solution, creating a favorable environment for the dissolution of precious metals. However, there are differences in their performance and considerations for their use:
### Lime (Calcium Oxide, CaO):
1. **Alkalinity Source:**
- Lime provides alkalinity to the leach solution by reacting with water to form hydroxide ions (OH⁻). This increase in pH facilitates the dissolution of gold and silver.
2. **Carbonate Formation:**
- Lime may contribute to the formation of carbonate ions (CO₃²⁻) in the leach solution, especially if carbon dioxide is present. Carbonate formation can affect the stability of the solution.
3. **Slaking Process:**
- Lime is typically added as a slurry (slaked lime or milk of lime), and the slaking process is essential to ensure proper dispersion and reactivity.
4. **Cost-Effective:**
- Lime is often considered more cost-effective than caustic soda, making it a preferred choice in many cyanide leaching operations.
5. **Precipitation of Impurities:**
- Lime can assist in the precipitation of certain impurities, such as heavy metals, which may be present in the ore or formed during leaching.
### Caustic Soda (Sodium Hydroxide, NaOH):
1. **Alkalinity Source:**
- Caustic soda provides alkalinity by dissociating into hydroxide ions (OH⁻) in solution. It directly contributes to the increase in pH.
2. **No Carbonate Formation:**
- Unlike lime, caustic soda does not contribute to carbonate formation, which can be advantageous for maintaining a stable leach solution.
3. **Ease of Handling:**
- Caustic soda is a liquid and is generally easier to handle and feed compared to lime, which is often delivered in the form of dry powder or slurry.
4. **pH Control:**
- Caustic soda allows for more precise control over pH due to its direct contribution of hydroxide ions without the complicating factor of carbonate formation.
5. **No Slaking Process:**
- Unlike lime, caustic soda does not require a slaking process, simplifying the handling and addition process.
### Considerations:
1. **Cost:**
- Lime is typically more cost-effective than caustic soda, which may influence the choice of reagent based on economic considerations.
2. **Solution Stability:**
- Caustic soda may offer better solution stability by avoiding carbonate formation, which can lead to precipitation and scale formation.
3. **Impurity Precipitation:**
- Lime may be preferred if impurity precipitation is desirable, but this needs to be balanced against potential carbonate-related challenges.
4. **Handling and Safety:**
- Caustic soda, being a liquid, may have advantages in terms of ease of handling and safety compared to lime dust.
Ultimately, the choice between lime and caustic soda depends on factors such as cost, solution stability, impurity precipitation requirements, and ease of handling based on the specific conditions and goals of the cyanide leaching operation. It is essential to consider the specific characteristics of the ore, the desired leaching conditions, and economic factors when selecting the alkaline reagent.
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Hello everyone,
I am trying to isolate antimicrobial peptides from plants. After precipitating the peptides with acetone, most of the pellet (peptides) did not dissolve. I used dH2O/PBS to dissolve the pellet. I do not want to use SDS or urea to dissolve the pellet because it will affect my cell culture experiment.
This is my peptides isolation protocol:
-The plant material was ground in a blender. For extraction, 10% CH3COOH (Acetic Acid) in the presence of a commercial proteinase inhibitor was added to the floured plant parts (added to the ground material at a ratio of 1:10 (w:v)).
- The extraction was carried out with continuous vigorous stirring for 1 h at room temperature. After 1 h, mixture was sieved; fine particles were separated by centrifugation at 4700 rpm for 10 min. The supernatant was filtered through a Whatman paper filter.
-Cold acetone (-70 °C) was poured into the filtrate at a ratio of 1:7 with gentle stirring; the mixture was then kept at +4 °C for overnight.
-After this time, the suspension was centrifuged at 4700 rpm for 10 min. The supernatant was removed and the resulting fraction was dried at room temperature. The dried precipitate was redissolved in dH2O or PBS.
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Try dissolving it in dimethylsulfoxide (DMSO). This is a water-miscible solvent that is generally very useful for this sort of thing, and it is compatible with subsequent biological experiments when diluted to a few % by volume.
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When I tried to prepare a solution of enzalutamide of 1000 uM in cell culture medium from a solution of 1 M of enzalutamide in DMSO the drug precipitated. I've tried changing the pH and the temperature but without success. :( Any tips?
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The stuff is insoluble in water. The best you can do is a suspension.
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What is the next step i can move on to with this material to create some value-added product
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I have downloaded 5 years daily precipitation data of MSWEP, but i havent succeded in subsetting it for Indonesia region and make pandas dataframe of it using python. Please advise?
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Follow these steps using Python:
1. Install the necessary libraries:
````
pip install pandas
```
2. Import the required libraries:
````python
import pandas as pd
```
3. Load the data: Assuming you have your MSWEP precipitation data in a CSV file, you can load it into a pandas dataframe using the `read_csv()` function. Provide the path to your CSV file as the argument:
````python
data = pd.read_csv("path/to/your/mswep_data.csv")
```
4. Subset the data for Indonesia: assume you want to subset the data for a latitude range of -11 to 6 and a longitude range of 95 to 141:
````python
indonesia_data = data[(data['latitude'] >= -11) & (data['latitude'] <= 6) & (data['longitude'] >= 95) & (data['longitude'] <= 141)]
```
Replace `'latitude'` and `'longitude'` with the column names that contain the corresponding information in your dataset.
5. Create a pandas dataframe: create a new dataframe with those columns. For example, if you want to keep the date and precipitation columns:
````python
indonesia_df = indonesia_data[['date', 'precipitation']]
```
Replace `'date'` and `'precipitation'` with the column names that represent the date and precipitation values in your dataset.
6. Optional: Save the subsetted dataframe to a new CSV file:
````python
indonesia_df.to_csv("path/to/save/indonesia_precipitation.csv", index=False)
```
This step allows you to save the subsetted data to a new CSV file if you want to use it later.
Hope it helps.
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I am trying to prepare a Ni-based catalyst(Ni/Ce2O3) by co-precipitation method. I was wondering what is the best precipitation agent and PH.
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Azita Etminan You don't mention the concentration of Ni you require in the final material but the usual route to produce catalysts of this nature with Ni in the 1 - 5 wt% typically is by impregnation of the base material (e.g. Ni/SiO2, Ni/CaCO3 etc) and then subsequent reduction. Simple precipitation of Ni salts with base produces Ni(OH)2 which will calcine to NiO and not Ni.
The preferred route would need a knowledge of the pore volume of the base (do you really mean Ce2O3 and not CeO2?). This knowledge can be obtained by simple titration of a known amount of the dry material or via porosimetry. A solution of the appropriate Ni precursor (nitrate would always be preferred over chloride) would be used to just saturate the pores and produce an x wt% Ni in the final powder. Reduction would then take place (in the dry with H2; in the wet my preferred reductant would be 5 or 10% hydrazine hydrate as the only products are water and N2). This would then produce Ni in the required concentration on the substrate. A further drying process would be needed for wet reduction. I'd avoid borohydride reduction as this always leaves intractable B in the matrix.
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Is there a method or equations that can be used to proved the relationship between water content and precipitation?
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There will be too much variation to do this calculation accurately without more information. As air temperature, soil type, soil permeability, presence and abundance of vegetation, vegetation type etc. will influence the relationship. Although previous publications have investigated this relationship, see below for a few examples:
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In Water Resources Engineering, the sizing of reservoirs depends on accurate estimates of water flow in the river that is impounded. For some rivers, long-term historical records of such flow data are difficult to obtain. In contrast, meteorological data on precipitation have often been available for many yearst. Therefore, it is often useful to determine a relationship between flow and precipitation. This relationship can then be used to estimate flows for years when only precipitation measurements were made. For example, the following data are available for a river that is to be dammed:
Precipitation=[88.9 108.5 104.1 139.7 127 94 116.8 99.1]
Flow=[14.6 16.7 15.3 23.2 19.5 16.1 18.1 16.6]
How can I put the best line with linear regression to predict the annual water flow on the data?
if the drainage area is 1100 km2, estimate what fraction of the precipitation is lost via processes such as evaporation, deep groundwater infiltration, and consumptive use.
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Hello,
To put the best line with linear regression to establish an equation between precipitation and flow data, you can use software or programming tools that provide regression analysis capabilities:
1. Microsoft Excel (easy to use): You can use the built-in regression analysis tool and curve fitting through selecting the appropriate regression model.
2. SPSS, and dozens of statistical tools
3. R: Use the statistical programming language R, which has different packages like `lm()` or `stats::lm()` for linear regression modeling.
The estimation of the fraction of precipitation lost via evaporation, infiltration, percolation, and consumptive use, requires additional information and data specific to the river and upstream watershed to consider comprehensive water balance analysis (currently data is anot sufficient).
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Hello! I need some guidance or clarification regarding the units for precipitation rate or precipitation intensity (esp. for rainfall). I'm used to precipitation intensity being expressed in millimeter per hour (mm h-1), but I noticed that reanalysis data generally express precipitation intensity in kilogram per square meter per second (kg m-2 s-1) which somehow confuses me.
I've read somewhere that when converting from kg m-2 s-1 to mm h-1, the value just have to be divided by 3600. And that in terms of precipitation amount/accumulation, 1 mm of rain is equal to 1 kg m-2. I knew that it has something to do with liquid water having a density roughly equal to 1 kg L-1, but the explanations were rushed so I'm still confused on how these two units are related to each other.
So, I would like to ask: how exactly do we convert precipitation rate from kilogram per square meter per second (kg m-2 s-1) to millimeter per hour (mm h-1), and vice versa? How does the dimensional analysis for these units work out, and what is the conversion factor for this? In addition, how exactly do we also convert precipitation amount from mm to kg m-2, and vice versa?
Thank you very much in advance!
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I agree with @Andreas, this is a simple conversion from mass fluxes into volume fluxes, and the difference between them is the density of water. By the way, I suggest reading the handbook of different datasets carefully, because each dataset has a different definition for their rain amount.
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Hello all,
I am currently trying to purify a fragment of the large surface protein of HBV however during purification I notice that a white precipitate form on the Ni-NTA column. (At pH 8.0; pI of protein = 6.97) I'm using a simple lysis buffer (50 mM imidazole, 50 mM NaH2PO4, 300 mM NaCl, (5% glycerol in some cases but no significant difference))
The protein was in solution in the cell lysate, ie before loading onto the column and the precipitate is confirmed to be my protein.
Washing and eluting at pH 8 resulted in a milky, cloudy white eluate.
Washing and eluting at lower pH of below 6 has helped to solubilize protein and the solution is clear.
For subsequent experiments I need to bind my protein to Ni-NTA carrying liposomes but as soon as my protein comes into contact with them it precipitates. The protein also precipitated when adding a bit of NiSO4 solution.
Any ideas as to how I can avoid this issue?
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Do you observe the same precipitation when using IMAC columns with immobilized Cobalt, Copper or Zinc ions? You can basically screen all the first row transition metals for that matter.
Good luck!
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Why does a solution of 50mM Tris and 20mM CaCl2 sometimes precipitate?
This buffer is used for protein purification.
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Well, you do not provide enough information. What is the working pH of this solution? I guess is around 8.0. Ca ions will tend to produce calcium hydroxide species under high pH conditions, which could precipitate.
20nm does not make sense either, is it 20 nM, 20 mM? The precipitation will also be favored if you lower the temperature of the buffer.
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Hello! I have been trying to purify an antibody using protein A column chromatography but noticed that as soon as the antibody equate hits the neutalisation buffer (Tris, NaOH, ph 9) it forms a cloudy precipitate. Any advice?
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i purified a lot of different mabs using protA from Expi293 surnatants using Triua 1M pH9 for neutralizzationever observed precipitation after elution
Generally what i do is:
1) Dliute directly in a falcoon containig the Tris 1M pH9 (1/20 of the ELution volume is ok) and after this change the buffer in PBS using desalting coloumn
2) ProtA elution could be performed more genlty than protG using citrate pH3,0 instead glycine pH2.7
in the attached link you can find the exact buffer composition than i'm using;
just a comment: in my experience ExpiCHO work much better in term of yields than Expi293 for the production of antibodies. Those cells are more expensive in terms of cost for liter and you need a second shaker working at 32°C for incubate the cells during transfection but in my experience the productivity is quite higher (3-4 fold)
Here you can find an example
good luck
Manuele
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Hi
I intend to model a thermal responde we measured with ERA5 variables, and later, use this model to predict the future responde with CMIP6 variables.
My doubt is, how to use precipitation correctly?
In ERA5 hour analysis total precipitation comes in meters acumulated in 1hour (so its m/h I suppose) and in CMIP6 comes in Kg/m2/s .
Kg/m2/s is the same as mm/s, so I'm wondering if turning ERA5 precipitation from meters/hour to mm/s and use that in a valid way?
Also, am I messing up units considering the grids are not even the same in both datasets?
Thank you!
Cheers, Luís Pereira.
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Hi Luis
To convert precipitation from g/m**2/s , you have to multiply by 3.6 to get precipitation in mm/hour. Since 1g=0.001kg, we can match units of kg/m**2/s to mm/hr. Now if you have the time of accumulation of precipitation in hr, you can easily match the two units (kg/m2/sec to meter).
See "On the continuity and distribution of water substance in atmospheric circulations" by E. Kessler, Atmospheric Research 38 (1995) 109-145.
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We want to dope 1% mol of Fe3+ in MgO by precipitation method. All precursors are nitrate salts and NaOH is precipitant.
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Thanks so much for your reply.
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I'm trying to start modeling asphaltene precipitation. Since I read studies related to asphaltene precipitation, I have found that modeling with PC-SAFT equation of state is most appropriate.
However, I don't have any software or MATLAB code that can model VLE and LLE for the system with multicomponents.
Would you please recommend me some free software or code for PC-SAFT EOS?
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Clapeyron.jl has implementation of PC-SAFT (and many other EoS) in Julia programming language.
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Hi,
In the chloromethylation reaction of polysulfone (PSU), I am required to use paraformaldehyde and trimethylchlorosilane as the chloromethylating agent while stannic chloride as the catalyst. I followed the same protocol of many papers such as this one attached.
During the experiment, PSU was first dissolved separately in solvent (e.g dichloromethane and chloroform) then paraformaldehyde (PFA) was added in form of solid. For both solvent and at two different dissolution temperatures (25 and 60 °C), the PFA was not fully dissolved.
I tried to dissolve PFA separately in solvent than add it to the dissolved PSU, this slightly improved the degree of chlore in the produced chloromethylated PSU (C-PSU), however it was not dissolved and gelation as well as non-homogeneity was obtained. Moreover, the obtained C-PSU was not soluble in many solvents (e.g. NMP, DMAc, DMSO, Toluene, DMF), which can be caused by the low degree of functionalization ( -CH2Cl) and the precipitation of insoluble cross-linked polymer.
I am aware that PFA is
  • slightly soluble in alcohol
  • soluble via depolymerization by heating PFA in distilled water at 60°C followed by a titration with NaOH
Which I already tried and it was successful in terms of PFA dissolution. The problem is that I don’t want water in my reaction due to the future application of the system.
I would appreciate if you could help me to improve my system by providing some suggestions on how to achieve a good homogeneous PFA/solvent solution. Any ideas on how to increase the degree of chloromethylation of PSU are very welcomed.
Thank you
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For chloromethylation of polysulfone, sulfolane can be used, which is штуке and non-toxic.
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I want to identify a secretory protein that is secreted from min6 cell in the supernatant can anyone provide protocols?
Firs I want to get conditioned media and then precipitate after that I will do SDS-PAGE and CBB/silver staining. I am a newbie so I don't know how much medium, how much cells is needed for this assay, I couldn't find a good reference
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Hello Sya Retno,
I have found a good reference for you. The work done is almost similar to the work you plan to carry out for your project.
Please refer to the paper attached below. The protocol provided in the article will be helpful.
Best.
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how can I obtain free precipitation, temperature, and potential evaporation data for a specific lake for the past 20 years?
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Dear Saba Moshtaghi,
The availability of historical climate data can fluctuate based on the specific location and the particular parameters of interest. To ensure accurate data retrieval, it is crucial to possess the precise name and geographic coordinates, including latitude and longitude, of the lake in question.
Numerous government agencies, such as the National Weather Service, diligently gather and manage climatic data for various locations, including lakes. Additionally, you can explore organizations and websites that offer access to climate data, such as NASA's Earthdata Search and the World Meteorological Organization.
It is worth noting that certain datasets may necessitate permissions or subscriptions for access, requiring initial registration. Furthermore, depending on your research objectives, it may be advisable to consider data from at least three nearby weather stations and compute an average. This becomes especially critical when dealing with rainfall data, as precipitation patterns can vary significantly both temporally and spatially.
humble regards,
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I have experience in studying the impact of hydrogeology on catastrophic floods. An example would be the flooding in Europe in the summer of 2002. See my discussion "How is geodynamics and hydrogeology taken into account?". see my publication "Floods and droughts as a result of deformability of the geological environment" for details.
The water content of the rivers is formed by atmospheric precipitation and underground waters. Influence of underground waters on water content of the rivers cannot be measured. It is shown that the volume of underground water exchange is underestimated and can be commensurable with a volume of atmospheric precipitation. Change of level of underground waters is defined by changes of volume of the geological environment during geodeformations. It is offered to consider geodeformations as one of the reasons of floods and droughts. Studied the changes the gravitational field and geodeformations during droughts and floods in the Amazon in 2005-2006. Studied the hydrological regime of the River Nile. Shows the influence of geodeformation on the level of Danube and Dniester. Proposed detailed study the causes of floods in Europe in 2002. Influence of the Earth’s surface deformation on floods and droughts is very important and requires special detailed study. Changes in volume of rocks during Earth's surface deformation are accompanied by dilatancy which influence on the amount of drought and flooding has turned out to be significant. Study of the processes considered in the thesis gives grounds to expect that floods and droughts associated with deformations of the geological environment will be successfully predicted. Foto https://www.google.com/url?sa=i&url=https%3A%2F%2Fren.tv%2Fnews%2Fv-mire%2F1138805-v-chernomorskom-regione-turtsii-livni-vyzvali-navodneniia&psig=AOvVaw2SdhsJ2lm16vYlBvplRoZX&ust=1694020292799000&source=images&cd=vfe&opi=89978449&ved=2ahUKEwjyktC_-5OBAxWdEBAIHSPSCyEQr4kDegQIARBc
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Yesterday it was the syzygy of the tide in the solid body of the Earth and the extreme of the angular velocity of the rotation of the earth. There is convective cloudiness above Turtsmey again. Where does water come from? These are hydrogeodynamic processes that accompany seismic manifestations.
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The Impact of Climate Change on Water Resources..... how do you measure precipitation threshold to be classified as a storm event in louisiana?
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On Climate Models: From General Circulation Models (GCMs) and Earth System Models (ESMs). General Circulation Models (GCMs)which are the core of weather forecasting Models appeared in the 1960s with the pioneer's work of Manabe (2021 Nobel Prize in Physics). A fundamental point is that is difficult to speak about GCMs and even less of Climate Models without a minimum review starting from Atmosphere Dynamics Models genesis in the 1960s to the actual Earth System Models (ESMs) that participated in the last "CMIP6". These represent the State-of-art of universal knowledge about Climate and its modeling. The results published in 2021 covers 80 ESMs from as many research teams throughout the world. Nowadays, Climate Science and Modelling have attained an international critic-mass never reached in any other domain.
ESMs include a number of components that try to describe the evolution of intercoupled phenomena that govern Climate Phenomena. To understand how this works, one has to know about the progress achieved and still-opened questions related to Climate Models. Mathematically the resolution of the dynamic and the transport equations of physical quantities on more or less important scales provide accurate predetermination in a relatively short time. This is what meteorologists do to deliver us every day their newsletter. This is what the same meteorologists are trying to do with scientists from all sides to build climate models in the long term, sure inaccurate today, exactly as was the 1960s weather model of Manabe, Nobel Prize in Physics 2021, the pioneer of general circulation modeling. The very first general circulation models were based on atmosphere-only physical models (Manabe et al., 1965, Nobel Prize in Physics, 2021), which were quickly improved to take into account the hydrologic cycle and its role in the general circulation of the atmosphere (Smagorinsky et al. 1965). From there, climate modeling has made considerable progress by gradually integrating the many positive or negative feedback processes that occur at different scales between the different components of the system: ocean circulation (Manabe and Bryan, 1969), land hydrological processes (Sellers et al., 1986), sea ice dynamics (Meehl and Washington, 1995), and aerosols (Takemura et al., 2000), biophysical and biogeochemical processes (Cox et al., 2000). Models with these latter components are often called Earth System Models (ESMs) and more recent such models include land and ocean carbon cycle, atmospheric chemistry, dynamic vegetation, and other biogeochemical cycles (Watanabe et al., 2011, Collins et al., 2011). It should be noted that as a whole and for the same reasons, the horns of ESMs, which are based on physical formulations similar to those employed in general circulation models applied in meteorology, have not evolved much, except for the increase in the resolution of the calculations made possible thanks to the increase in the computing capacity or their capacity to assimilate increasingly abundant and precise data; in particular global satellite data, which complements and connects measurements on the ground or at low altitude.
Manabe, S., Smagorinsky, J., & Strickler, R. F. (1965). Simulated climatology of a general circulation model with a hydrologic cycle. Monthly Weather Review, 93(12), 769-798.
Smagorinsky, S. Manabe, and J. L. Holloway, “Numericd Results From a Nine-Level General Circulation Model of the Atmosphere,” Monthly Weather Review, vol. 93, No. 12, Dec. 1965, pp. 727-768.
Manabe, S., & Bryan, K. (1969). Climate calculations with a combined ocean-atmosphere model. J. Atmos. Sci, 26(4), 786-789.
Sellers, P. J., Mintz, Y. C. S. Y., Sud, Y. E. A., & Dalcher, A. (1986). A simple biosphere model (SiB) for use within general circulation models. Journal of the atmospheric sciences, 43(6), 505-531.
Meehl, G. A., & Washington, W. M. (1995). Cloud albedo feedback and the super greenhouse effect in a global coupled GCM. Climate dynamics, 11(7), 399-411.
Takemura, T., Okamoto, H., Maruyama, Y., Numaguti, A., Higurashi, A., & Nakajima, T. (2000). Global three‐dimensional simulation of aerosol optical thickness distribution of various origins. Journal of Geophysical Research: Atmospheres, 105(D14), 17853-17873.
Cox, P. M., Betts, R. A., Jones, C. D., Spall, S. A., & Totterdell, I. J. (2000). Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model. Nature, 408(6809), 184-187.
Watanabe, S., Hajima, T., Sudo, K., Nagashima, T., Takemura, T., Okajima, H., ... & Kawamiya, M. (2011). MIROC-ESM 2010: Model description and basic results of CMIP5-20c3m experiments. Geoscientific Model Development, 4(4), 845-872.
Collins, W. J., Bellouin, N., Doutriaux-Boucher, M., Gedney, N., Halloran, P., Hinton, T., ... & Woodward, S. (2011). Development and evaluation of an Earth-System model–HadGEM2. Geoscientific Model Development, 4(4), 1051-1075.
See Also:
Besbes, M., & Chahed, J. (2023). Predictability of water resources with global climate models. Case of Northern Tunisia. Comptes Rendus. Géoscience, 355(S1), 1-22. Available on:
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I am trying to extract gDNA from culturable endophytes isolated from Gum trees but have not been getting good result from the protocol attached. The endophytes are pigmented.
I used mycelia of endophytes cultured in broth. After centrifuge of precipitation step, the DNA pellete was contaminated with dark colour (dark pellete). So I did not proceed further.
I than repeat the extraction but this time I ground mycelia in liquid nitrogen and use the same extraction protocol. I obtained white precipitated DNA pellet unlike the previous one. Then I dissolved DNA pellete in milliQ water. The NanoDrop readings were well below A260/230 and DNA yield was very poor.
If anyone/experts of endophytes can help me with DNA extraction advice.
I am using fresh mycelia of endophytes cultured in both broth and on solid agar. Both still hasn't yield good result.
DNA extraction protocol attached.
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I have searched the web for some possible solutions and advice for your problem. Here are some of the results that I found:
  • A simple and efficient method for DNA extraction from grapevine cultivars, Vitis species and Ampelopsis by A. Lodhi, G. N. Ye, N. F. Weeden, and B. I. Reisch, Plant Molecular Biology Reporter, vol. 12, no. 1, pp. 6-13, 1994. This paper describes a method for DNA extraction from grapevine and related genera using cetyltrimethylammonium bromide (CTAB) buffer and polyvinylpyrrolidone (PVP). The method is reported to be effective for removing polysaccharides, polyphenols, and other contaminants that interfere with DNA quality and quantity. The method is also suitable for PCR amplification of DNA fragments.
  • A rapid and efficient method for isolating high quality DNA from leaves of carnivorous plants from the Drosera genus by M. Tretyakova, A. Romanovskaya, A. Shmakov, and V. Sizykh, BMC Research Notes, vol. 7, no. 1, 926, 2014. This paper presents a method for isolating high quality DNA from leaves of carnivorous plants from the Drosera genus using CTAB buffer and PVP. The method is claimed to be rapid and efficient, as it takes less than 3 h to complete and yields DNA with high purity and integrity. The method is also compatible with PCR amplification of DNA fragments.
  • A simple method for isolation of genomic DNA from fresh and dry leaves of Terminalia arjuna (Roxb.) Wight & Arn., a medicinal plant by S. Kaur, R. Ahuja, S. Kumar, R. Chaudhury, and A. Srivastava, Molecular Biotechnology, vol. 40, no. 2, pp. 167-172, 2008. This paper describes a method for isolating genomic DNA from fresh and dry leaves of Terminalia arjuna, a medicinal plant with high levels of secondary metabolites that hamper DNA extraction. The method involves the use of CTAB buffer with PVP and β-mercaptoethanol (β-ME), followed by chloroform-isoamyl alcohol (CIA) extraction and isopropanol precipitation. The method is reported to yield high quality DNA that can be used for PCR amplification of DNA fragments.
Based on these results, it seems that CTAB buffer with PVP is a common solution for extracting DNA from plant materials that have high amounts of pigments and other contaminants that affect DNA quality and quantity. You may want to try this method or modify it according to your needs and see if it works better than the protocol you attached.
Here are the references
: [A simple and efficient method for DNA extraction from grapevine cultivars, Vitis species and Ampelopsis] by A. Lodhi, G. N. Ye, N. F. Weeden, and B. I. Reisch, Plant Molecular Biology Reporter, vol. 12, no. 1, pp. 6-13, 1994.
: [A rapid and efficient method for isolating high quality DNA from leaves of carnivorous plants from the Drosera genus] by M. Tretyakova, A. Romanovskaya, A. Shmakov, and V. Sizykh, BMC Research Notes, vol. 7, no. 1, 926, 2014.
: [A simple method for isolation of genomic DNA from fresh and dry leaves of Terminalia arjuna (Roxb.) Wight & Arn., a medicinal plant] by S. Kaur, R. Ahuja, S. Kumar, R. Chaudhury, and A. Srivastava, Molecular Biotechnology, vol. 40, no. 2, pp. 167-172, 2008.
Annulohypoxylon sp. strain MUS1, an endophytic fungus isolate...
Good luck
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Which type of cloud is most likely to produce precipitation and process in which any product of condensation of atmospheric water vapour falls under gravity?
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Dr Raffaele Salerno thank you for your contribution to the discussion
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Antimicrobial material which is insoluble in water. When I dissolve in DMSO and diluted it with water(%10), it precipitated in the bottom of the tube. how can I use material for antimicrobial test?
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Surfactants do not "dissolve" - they emulsify and disperse
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I have a sample in the dissolved state. Acetone acts as an anti-solvent to precipitate the substance from the DMSO solution. However, the recovery yield is low. Is there any method to collect the samples in maximum yield?
Filtration can't be used as it will decrease the yield. I'm using centrifugation, to collect the samples now. Does anybody have any suggestions?
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Even Xu Thank u. But, I'm working with chemical polymers.
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I am producing a flocculent precipitate when doing free radical polymerization of itaconic acid in aqueous solution, what should this substance be? How is it produced?The initiator is sodium persulfate at five percent of the total reactants, and the reaction temperature is 80 ℃.
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I don't think 5000 MW is a polymer, may be it is a true oligomer. You should search and find kinetics studies on MW evolution with respect to polymerization time. These are old studies. My Regards
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With the help of standardized Precipitation Evapotranspiration Index how we get return period of drought?
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This article might be helpful for you:
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We synthesized a peptide made up of 7 amino acids. After cleaving the peptide with TFA, we tried to precipitate the peptide from cold ether. However, it seems like our peptide is somehow soluble in ether. Are there any other organic solvents to precipitate peptides?
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You could lyophilize the mixed solution TFA-ether that contains the peptide.
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How can I train an ANN using current raster data (population, precipitation, DEM, land use) and use this model to predict future land use based on upcoming raster data (population, precipitation, temperature)?
I've been studying the relevant theory extensively recently, and I'd like to find a case study to see how it's practically implemented. Could you please guide me to where I can find similar case studies? I've noticed that many papers follow this approach, but I'm struggling to locate any code examples.
If there are no case studies available, I'd like to understand how to use raster data as inputs for an ANN and what preprocessing steps are needed, especially when dealing with multiple raster data inputs.
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Hi,
utilizing an Artificial Neural Network (ANN) to predict land use based on raster data is a potent application of machine learning in geospatial analysis. This approach involves training a model on historical raster data, such as population, precipitation, Digital Elevation Model (DEM), and existing land use, and then leveraging this trained model to forecast future land use patterns using forthcoming raster data containing parameters like population, precipitation, and temperature.
To practically implement this approach, you can follow these steps:
  1. Data Collection and Preprocessing:Gather historical raster data encompassing relevant variables like population, precipitation, DEM, and land use maps. Acquire future raster data with the same variables but updated parameters (population, precipitation, temperature). Ensure consistent spatial resolution, extent, and coordinate system for all raster datasets. Convert categorical data, like land use types, into numerical representations, potentially using one-hot encoding.
  2. Data Splitting:Divide the historical raster data into training and validation sets. The validation set helps in monitoring the model's performance during training. Organize the data as input-output pairs, where the inputs consist of combined raster data (population, precipitation, DEM, etc.), and the output is the corresponding land use category.
  3. Feature Standardization and Normalization:Standardize numerical features (e.g., population) to have a mean of 0 and standard deviation of 1 to aid model convergence. Normalize data within a specific range (e.g., [0, 1]) to prevent any feature from dominating the learning process.
  4. ANN Model Architecture:Design the neural network architecture with an input layer that matches the number of features in your raster data and output layers that correspond to the number of land use classes. Incorporate hidden layers with appropriate activation functions (e.g., ReLU) to capture complex relationships between input features.
  5. Model Training:Train the ANN using the training dataset and monitor its performance on the validation set. Optimize the model's parameters (weights and biases) using backpropagation and optimization algorithms (e.g., Adam, SGD). Utilize appropriate loss functions (e.g., categorical cross-entropy) to quantify the model's prediction accuracy.
  6. Model Evaluation:Assess the model's performance on the validation set using metrics like accuracy, F1-score, and confusion matrix. Fine-tune hyperparameters (e.g., learning rate, number of hidden layers, neurons per layer) based on validation performance.
  7. Future Land Use Prediction:Once the model is trained and validated, input the upcoming raster data (population, precipitation, temperature) to predict future land use patterns. The model's output will be a probability distribution across land use classes; you can choose the class with the highest probability as the predicted land use.
As for case studies and code examples, you can explore academic journals, conferences, and online repositories like GitHub. Many researchers have indeed explored this approach, but the specific code examples might not be readily available due to variations in dataset availability and implementation choices. Look for papers that discuss their methodology in detail; they often provide insights into the data preprocessing, model architecture, and evaluation techniques used.
If you find my reply is useful , please recommend it .Thanks
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Hallo,
I have produced citric acid crosslinked samples of magnesium and sodium lignosulphonates and tried to precipitate my samples as they were water soluble during washing .I tried to preciptate with 0,1M , 1M and 2M HCl but none of it caused precipitation of my sample.The pH of the crosslinked sample was between 3-4.
Could anybody please suggest any other methods to precipitate the sample or a possible reason for no precipiation.
Thank you very much
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Anumol James Addition of alcohol?
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Hello, could someone assist me in interpreting the results of the sequential Mann-Kendall Sneyer test? Indeed, according to Dufek (2008: Precipitation variability in São Paulo State, Brazil), "In the absence of any trend, the graphical representation of the direct series (u(t)) and the backward series (u'(t)) obtained with this method yields curves that overlap several times." In my case, I observe two to three overlaps, often with sequences that exhibit significant trends. Should I also conclude that there is an absence of trends in my dataset?
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The sequential Mann-Kendall test, also known as the Mann-Kendall-Sneyers (MKS) test, is a variation of the Mann-Kendall test that aims to detect trends in time series data. The test involves comparing the original time series to its reverse version to identify potential trends. The graphical representation of the direct series (u(t)) and the backward series (u'(t)) can provide insights into the presence or absence of trends. However, the interpretation can be nuanced.
Dufek (2008) suggests that if there is no trend, the curves of the direct and backward series will overlap several times. In your case, you observe two to three overlaps, often with sequences that exhibit significant trends. This situation requires careful consideration:
  1. Overlaps: The fact that you observe overlaps in the curves suggests that there might be a lack of consistent and significant trends in your dataset. If you're seeing two to three overlaps, it could indicate a certain level of fluctuation without a clear upward or downward trend. However, it's important to consider the magnitude and duration of these overlaps. Short overlaps might be less indicative of a lack of trend than longer ones.
  2. Significant Trends: The presence of sequences with significant trends might complicate the interpretation. Significant trends imply that some portions of the data are exhibiting systematic changes over time. The presence of these trends could be in contrast to the overlaps you observe.
  3. Complex Patterns: Time series data can exhibit complex patterns that might not be captured by a single test or method. Overlapping curves and significant trends suggest that the behavior of your data might be more intricate than a simple upward or downward trend.
  4. Data Context: Consider the context of your data and the subject matter. Sometimes, fluctuations and variations might be inherent to the process being studied, and these might not necessarily indicate a clear trend.
In conclusion, while the observation of overlaps in the graphical representation of the sequential Mann-Kendall test might suggest a lack of clear trends, the presence of significant trends in some segments complicates the interpretation. It's important to analyze the trends, magnitudes, and durations of both overlaps and significant trends while considering the broader context of your data and the subject matter you're studying. If possible, consulting with a statistician or subject-matter expert might help you make a more informed interpretation of your findings.
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I performed DLS on purified exosomes with an EXO SPIN kit (precipitation and size exclusion chromatography) the Z-average was too big and the result wasn’t good I should mention that to break up aggregations I do sonication before analysis. Does anyone have any idea? Could filtering through 0.2 µm be a solver?
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Hi,
Exosome size measurements through DLS tend to be variable , thus should be repeated several times in single as well as multiple different preparations, in order to reach a cumulative particle size range . Please pay attention towards QC report at the end of each measurement ('Good' report means acceptable results). Further you may need to modify the default DLS protocol method in order to fit EV measurements.
Filtering through 0.2um could be helpful but sonication will break up the EV particles giving incorrect sizes.
NTA is a better method to quantify EV size and concentration.
Regards
Neha
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Hi
I work on complex fe(iii)-tannic acid , but I find precipitate of blue-black color, although ph=2
Can any one help me?
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Dear Dr Sallam
The formation of a blue-black precipitate when iron(III) is mixed with tannic acid can be attributed to the formation of a complex between the two substances. Iron(III) ions (Fe³⁺) have the ability to form coordination complexes with various ligands, and tannic acid is a polyphenolic compound with multiple functional groups that can serve as ligands. The blue-black color of the precipitate suggests the presence of a specific complex that exhibits this color.
In a low pH environment (pH=2, as you mentioned), tannic acid molecules are likely to be partially or fully protonated, resulting in a higher concentration of positively charged species. These positively charged tannic acid species can interact with the negatively charged iron(III) ions, leading to the formation of coordination complexes.
The exact structure and composition of the complex formed between iron(III) and tannic acid can vary depending on factors such as the molar ratio of the reactants, the specific functional groups on the tannic acid molecules, and the conditions under which the reaction takes place. One possible complex that could contribute to the blue-black color is the iron(III)-tannic acid complex called "iron(III)-tannate" or "ferric tannate."
The blue-black color might arise from the interaction of the complex's structure with light, leading to absorption and reflection of certain wavelengths that result in this particular color perception. The complexity of the formed complex, along with its arrangement and electronic transitions, can contribute to the observed color.
If you're working with these complexes and observing the formation of a blue-black precipitate, it's likely that you are indeed forming a specific iron(III)-tannic acid complex. Characterizing this complex through techniques like spectroscopy (UV-Vis, IR, etc.) and elemental analysis could provide more insight into its structure and properties.
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Tell me, on which rim of the centrifuge (G) can the suspension of plant cells be precipitated without damaging the cells?
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Dear Ekaterina Anatolyevna Lapchenko,
Unfortunately, I do not have any experience or knowledge about this subject.
Best regards.
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I have been purifying a His-tagged protein first using Ni-NTA chromatography and then Gel Filtration. After purifying using Ni-NTA, the protein seems to be precipitated after keeping the protein overnight on ice (or even for few hours). The protein was eluted using a gradient of buffer using 500 mM Imidazole (in a buffer of 20 mM Sodium phosphate, 500 mM NaCl, 10% Glycerol, 1 mM DTT). I tried to remove the precipitation by centrifuging but it seems majority of it seems to be completely precipitated (very less in soluble fraction).
Any ideas? Thank you
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DTT reduces the Ni-NTA to Nickel solid making a brown precipitate. Did you observe that? Phosphate salts are have low solubility especially at cold temperatures in the cold room so if the sodium phosphate is precipitating, your protein is dissolved in it so it is precipitating with the sodium phosphate. Tris and Hepes are more soluble buffers and are better options and I think Tris is cheaper.
Your protein is least soluble when the pH of the solution equals the isoelectric point of your protein (pI) because the protein is uncharged at the isoelectric point. But for binding to Ni-NTA, the pH of the buffer has to be pH >= 7.8 because at lower pH, the polystidine tag is protonated and so it can't bind to Ni-NTA.
Plug your protein sequence into ProtParam to estimate the isoelectric point:
Try to avoid having the pH of your buffer being near the isoelectric point.
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In the past I have conjugated an acid to polyethyleneimine with percentage conjugation of around 25%. I wanted to increase this percentage, and so I doubled the amount of acid, EDC and NHS before this solution was added to the polyethyleneimine. After allowing to react in methanol, with no solubility issues, after I precipitated the polymer as normal in diethyl ether, I have found it is now insoluble in water or methanol. However, there was no suggestion of the polymer "crashing out" of solution in methanol while the reaction was stirring. Why is the polymer precipitate suddenly insoluble when this has never been an issue previously? The acid I am using is a simple phenylboronic acid.
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Yuri Mirgorod thanksnfor your help. Yes we found by lowering the pH of the solution we were able to dissolve the precipitate. Also found a paper regarding if PEI amines are unconjugated the amines will intertwine and need to be charged to electrostatically repel and allow dissolution.
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I test BOD of inlet sample of sewage water, in which there is no problem in inital DO but when i incubate it for 5 days, after incubation when i go for estimation of final DO, on addition of MnSo4 &Azide respectively the colour of bottle turns white insted of yellow & finally on addtion of H2So4 it totally yruns transparent. Whereas the other two samples of blank and outlet does not show such change.
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Dear Parvaiz,
Here is some additional information that may also be of interest. The brown precipitate is MnO(OH)2, containing Mn(IV), which forms when dissolved oxygen (DO) oxidizes the Mn(II) added in the form Mn(OH)2. If there is no DO in the sample after incubation, then the brown color will not form. Were the inlet samples sufficiently diluted so that some DO remained after the 5-day incubation? A dilution factor of 20-60 or more may be needed, depending on the sewage strength.
By the way, the azide is used to prevent interference caused by any nitrite present. If the lab sink has a U-trap made of lead, the unreacted azide going down the drain when you pour out the BOD bottles can react with the lead to form explosive lead azide (PbN6), posing a real risk to any plumber or other person who services or otherwise contacts the trap.
Best of luck with your work!
- Peter
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I am working on #RNA SELEX. During the process of converting RNA to cDNA, I found precipitation in the RT product. Can anyone suggest to me how to get rid of this precipitation? i am guessing I am not converting all RNA to cDNA; this precipitation might be the secondary structure formation. How to minimize this precipitate formation?
Thanks
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No, ethanol would not do anything of note, and the probability of 'leftover ethanol' being present should be zero.
Also, you state that your concentration is "very high, 3750ug" but this is an amount, not a concentration. 3750ug per what?
It would probably help, to be honest, if you provided a lot more detail about what you're doing at each step, and why you're doing it that way.
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I have precipitated out the protein using acetone from the alkaline-base buffer (NaOH + SDS+ EDTA + Beta Mercaptoethanol).
Desiccated Precipitates weigh more than the sample i.e for 2 grams of hair sample used, I am getting 2.6 grams of precipitates
Can one guide me on how can i separate my protein from the Desiccated Precipitates? Due to a limited budget, I can't use fancy techniques.
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You may also test meoh-chlorofom Folch precipitation method to get proteome as an interphase pellet...Alternatively, Trizol extraction could be beneficial...Trial and error-based approaches to get the highest recovery...
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I am doing Trend analysis. When I was doing Homogeneity tests ( Pettitt, SNHT test, Buishand, von Neumann) on Precipitation and Temperature time series using XLSTAT, I found that a great number of my Temperature data are inhomogeneous. Can anybody tell me How can I make them homogeneous data?
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Use normalization techniques such as min-max normalization or z-score normalization. Another method is to use feature scaling techniques such as standardization or normalization.
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I'm trying to reconstruct the time series of a weather station over the whole 1991-2020 period by using an external model as predictor.
I've successfully used ERA5-Land as predictor for temperature as the correlation with station data is quite high, however I'm struggling to do the same for precipitation.
What is the best alternative to reanalysis in this case? I was thinking about datasets of daily precipitation measured from satellite but the data seems to be quite coarse.
In my case I have the following requirements
  • Temporal coverage from 1991-01-01 onwards (at least until 2020-12-31, but extension to present is quite important)
  • Daily accumulated precipitation
  • Grid spacing lower than 0.25 degrees
  • Coverage of the Mediterranean area
You have any suggestions on which dataset I could use?
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Hello Guido,
try The Satellite Precipitation - CMORPH Climate Data Record (CDR) consists of satellite precipitation estimates that have been bias corrected and reprocessed using the the Climate Prediction Center (CPC) Morphing Technique (MORPH) to form a global, high resolution precipitation analysis. Data is reprocessed on a global grid with 8km-by-8km spatial resolution. Temporal resolution is 30 minutes over a 20 year period of record (January 1998–present). The output precipitation fields are produced on three different time-space resolutions to accommodate a variety of user requirements.
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We have been trying to detect cytokines from equine synovial fluid using milliplex equine cytokine/chemokine magnetic bead panel. However it is rather hard and the values are always below detection. Is there anyway we can improve our sample? Can TCA acetone precipitation help concentrating the proteins and would the proteins still be detectable if we use this method?
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With the Target 96 Immunopanels (INF, IO, IR) or the T48 cytokine panel you should be able to cover most (if not all) of your targets of interest.
Shoot me an email and I connect you to the closest sales person, if you are inetrested.
All the best,
Michael
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Hello, I tried to prepare 10g/L MnCl2 solution but it got precipitated. What can be the possible reasons?
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One possibility is that it is MgCO3 that is being precipitated with the carbonate being supplied from CO2 in the air. Are you using distilled or tap water?
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Hello all,
We cultured MSCs on calcium phosphate discs for 3 days and 7 days. We are seeing strange crystal-like precipitates or something of the sort (images attached). They are found wherever cells are found, or nearby cells, that are growing on the surface of the discs. We did EDS on these samples out of curiosity and the crystals appear to have a high concentration of NaCl, which indicates that they are salts.
I can't find any literature that shows this happening in their cell studies. Has anyone else seen this sort of thing happen in their cell cultures? I have no idea what could explain these results and I would appreciate some insights, or hypotheses, if any.
Thanks!
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Interesting observation! Based on your description, it seems like the crystals could indeed be salt precipitates. There could be several reasons for this, here are a few possible explanations. Media evaporation: If your cultures are not fully sealed or the incubator is not properly humidified, evaporation could cause the salts in the culture medium to become more concentrated over time. This might lead to precipitation, especially near cells which could act as nucleation points for crystal formation. Interaction with the disc material: Calcium phosphate could be reacting with components of the culture medium, leading to formation of insoluble salts. I hope these ideas help you in understanding and investigating this phenomenon further!
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I purified one protein using 3 different columns. The last column I used is Butyl 650M hydrophobic interaction column and I eluted my target protein with 50% propylene glycol. I need to remove propylene glycol and concentrate my elution. I tried to remove it with acetone precipitation, and methanol chloroform precipitation. However, both of them resulted in a significant loss of my protein.
I wonder If I can use dialysis or not...due to its water-absorbing characteristic...
I do not want to add additional steps like gel filtration chromatography...
Does anyone have any technical suggestions and ideas?
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Ultrafiltration...
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Hi Everyone
I need to improve the solubility of Potassium Humates in hard water. Generally, potassium humates are soluble in hard water but within a few minutes, it has precipitated due to the complexation of humates with Ca & Mg ions. Can anyone help me to avoid this precipitation or sedimentation?
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I suggest doing the dilution little by little under agitation and heating and doing a treatment to reduce the hard water salts. You could decalcify using ion exchange resins to capture calcium and magnesium from hard water.
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Hello, I am an undergrad trying to follow the methodology of the paper attached. I'm working with 50 mM phosphate buffer and 250 mM MgCl2 for hexokinase phosphorylation of CNF. I don't entirely understand why that concentration of buffer was used, and I keep getting Mg(OH)2 precipitates upon trying to get to pH 7.6. What could I be doing wrong?
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Often it is magnesium phosphate that is the precipitate. Usually you formulate your phosphate buffer to be the right pH based on the mix of mono- and di-basic phosphate that you add and then autoclave. You then add the magnesium when cold from a separate stock solution.
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Climate Data Operators (CDO)
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Dear Awad, to calculate seasonal precipitation Anomaly for 30 years using CDO you can do this as follows:
cdo ymonmean infile.nc outfile_climatology.nc #### The command "cdo ymonmean" is used to calculate the monthly mean of a dataset
and then
cdo ymonsub infile.nc outfile_climatology.nc outfile_anomalies.nc ####cdo ymonsub is used to calculate monthly anomalies from monthly climatologies
I hope this can help you
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Please somebody can share a script for ( to run on CDS toolbox editor https://cds.climate.copernicus.eu/toolbox-editor ) daily total precipitation data extraction on a point location for custom period (several years) ?
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Guyen Battuvshin, many thanks for your answer! I am just worring about "climate.daily_mean()" function - it is decleared to calculate only average value for each day, so here I see an issue.... or this function work in another way with precipitation data... Do you check results of this output?
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My polyurethane like polymer, when precipitated in ether gives a lower Mn while the same when precipitated in methanol gives a higher Mn. I have looked a lot in the literature to find some good explanation to it but seems to get nothing. Can someone please explain me.
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Dear all, in the precipitation process one should consider the binary state of solvent/nonsolvent mixture. In which solvent PU is being dissolved ? My Regards
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involving stations which have been set up recently in SPI mapping
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In addition to the excellent approach mentioned by Enda William O'Brien, which involves statistical adjustments based on available data, it is also possible to adopt approaches that take into account the scarcity of available data. One such approach is spatial interpolation, which is highly useful for estimating precipitation values in locations with insufficient data. By utilizing information from nearby stations with more complete records, it is possible to fill in the data gaps of recently installed stations.
Furthermore, historical data analysis from nearby stations with longer precipitation records can be employed to infer precipitation patterns in the area and fill in the data gaps of the new station, allowing for a better understanding of the climatic context in which the Standardized Precipitation Index (SPI) is being calculated.
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I have downloaded two types of half-hourly and three-hourly satellite precipitation data for the study area from Gportal. Now I have a question about those data, please help in this regard.
GPM_3IMERGHH half-hourly NetCDF file
3B-HHR.MS.MRG.3IMERG.20170322-S000000-E002959.0000.V06B.HDF5.SUB.nc4
Question 1: Does this file cover the amount of precipitation from 23:45 UTC of the previous day to 00:15 UTC of the current day or it represents the period from 23:30 UTC of the previous day to 00:00 UTC of the current day?
GPM_3IMERGHH half-hourly NetCDF file
3B-HHR.MS.MRG.3IMERG.20170321-S103000-E105959.0630.V06B.HDF5.SUB
Question 2: Does this file cover the amount of precipitation from 10:00 UTC of the current day to 10:30 UTC of the current day or it represents the period from 10:15 UTC of the current day to 10:45 UTC of the current day?
TRMM_3B42RT three-hourly NetCDF file
3B42.20170302.00.7.HDF.nc4
Question 3: Does this file cover the amount of precipitation from 22:30 UTC of the previous day to 01:30 UTC of the current day or it represents the period from 21:00 UTC of the previous day to 00:00 UTC of the current day?
GSMAP 1-hourly HDF file
GPMMRG_MAP_1703021800_H_L3S_MCH_04C.h5
Question 4: Does this file cover the amount of precipitation from 17:00 UTC of the current day to 18:00 UTC of the current day or it represents the period from 17:30 UTC of the current day to 18:30 UTC of the current day?
Kindest regards
Mahdavi
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Thanks to everyone, I got the necessary response from the support of the above products.
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I used linalool standard for estimating total terpenoid content for my plant sample, different linalool concentration has been taken and finally the supernatant has been discarded, the red precipitate ring is treated with solvent. while discarding the supernatant either micro ml of precipitate been drawn or left with micro ml of supernatant, due to this i am unable to draw a standard curve and the values are non-linear . kindly help me out to find a better way for doing this experiment
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Thank u for ur response Sir . But my work is to just estimate the total count of terpenoid using basic standard protocol. Now I switched to ursolic acid with some modified procedure for this estimation.
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  • Numerous studies have suggested that carbonation and serpentinization of silicate minerals are controlled by an interface-coupled dissolution-precipitation mechanism (e.g., Putnis, 2002, 2009, 2014; Plümper et al., 2012; Altree-Williams et al., 2015).
  • Moreover, this mechanism can lead to the pseudomorphic (isovolumetric) replacement of the parent phase by the product phase, assuming that the dissolution of the parent phase and the precipitation of the product are coupled in both space and time (Brugger et al., 2010; Putnis, 2009; Qian et al., 2010; Altree-Williams et al., 2015).
  • However, I'm curious about the question that "could the interface-coupled dissolution-precipitation mechanism necessarily also not lead to pseudomorphic texture generation?".
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The interface-coupled dissolution-precipitation mechanism, while often resulting in pseudomorphic replacement of the parent phase by the product phase, does not necessarily always lead to pseudomorphic texture generation.
This is because the generation of pseudomorphic textures depends on several conditions being met, including isovolumetric replacement, conservation of original grain boundaries, and retention of the parent phase's shape and size. These conditions may not always be met in all dissolution-precipitation processes.
Additionally, the generation of pseudomorphic textures can be influenced by a range of factors, such as the rate of reaction, the nature of the parent and product phases, the solution chemistry, and physical conditions like temperature and pressure.
Therefore, while the interface-coupled dissolution-precipitation mechanism often leads to a pseudomorphic replacement, it does not necessarily always lead to the generation of pseudomorphic textures. There can be cases where this mechanism could result in non-pseudomorphic replacement, particularly if conditions are not conducive to maintaining the original form of the parent phase during the replacement process.
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So far I have found partial data, not a global coverage.
Data by station or simply a raster image would be great, as I need to calculate the average wind speed and precipitation by subnational region (for which I have a shapefile with the administrative boundaries).
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merci Mohamed !
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Hi ResearchGate community,
I am interested in using chemical flocculation to concentrate water samples for eDNA analysis. This is basically to avoid having to filter water.
I have come across interesting papers on this subject, however, people use chemical flocculation for the precipitation of entire cells (bacterial communities). I am wondering if this method can also work when we are dealing with environmental samples (cells + mitochondria + free floating extracellular DNA + mucous + fecal matter, etc). I would appreciate if anyone with experience with this could comment. I am interested in knowing what is the % recovery of this method.
Thanks
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Nucleic acids, lipid, and colloidal particulate material can be selectively flocculated from a yeast cell homogenate by the cationic polymer polyethyleneimine (PEI). Flocculation can occur from a crude homogenate, a homogenate clarified centrifugally, or by the prior use of sodium tetraborate (borax).
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Hello eveyone,
I'm trying to conjugate azide-MMAE compound to a protein. The azide-containg group is soluble in DMSO. The problem is when i combine all the ingridients for the reaction i get precipitation and only the protein remains (checked in MS analysis). My theory is that the amount of DMSO is so little in the total amount of the reaction that the organic compound is not soluble anymore. How do i prevent the precipitation of azide-MMAE, while also not denaturing the protein?
My reaction is as follows (for 1 ml, 37C, 550 rpm, 2hr):
50 ul of 50mM THPTA
25 ul of 20mM CuSO4
160 ul of 31.195uM protein
20 ul of 5mM azide-MMAE (stock is 50mM and diluted with PBS)
50 ul of 100mM ascorbic acid
and PBS to 1 ml
I would appreciate any assistance on this matter.
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One strategy may be putting a hydrophilic spacer that increases the azide-MMAE compound's solubility in aqueous media for successful click chemistry. There are many options...
Refolding after bioconjugation may be the second strategy...
Third, non-ionic, non-denaturing mild detergent may also be helpful to increase solubility for MMAE. But I am not sure if this alters the conjugation...
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I have tried to modify gelatin with methacrylic anhydride (MA). However, when MA was added into gelatin PBS solution, it will form milky emulsion and a kind of precipitation. after dialysis, the precipitation can be reduced in some extent, but still exists.
can I ask whether this is a normal procedure or what should I do to avoid the precipitation?
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Just a follow up on this question. I've had the same issue now and wanted to ask: Did it affect down-stream applications? Did you remove the precipitate by centrifugation? Or did you simply start over?
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Hi, I have monthly precipitation and monthly temperature (not classified as minimum and maximum). How can I calculate SPEI index using Rstudio? I have also additional inputs like year, months and latitude of the location where I am conducting research.
Thank you!
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Thank you very much, appreciated!
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Hello all,
I recently started to use peptides for cellular studies. Unfortunately, when I was designing the peptides I did not have a FITC tag to them (the peptide was synthesized by an external company). The peptides still have an -NH2 terminal that I can react with FITC-NHS pretty easily. But due to the small size I would not be able to isolate the peptide from unreacted/hydrolyzed FITC-NHS by MW cutoff as I would for proteins.
The peptides are not very cheap so I would seek alternatives than purchasing more tagged peptides. While I know I could purify it by HPLC followed by concentration / lyophilization, it's adding a lot of procedures to the pipeline and I'm considering if there could be alternatives. And so, I'm wondering if peptides could be precipitated by TCA/acetone precipitation similar to proteins?
While I believe the precipitation is dependent on the peptide structure, I used one of our peptides and tried it out - the precipitation worked (I saw visual white fluffs) and the peptide absorbance curve showed peaks at 214/280. The curve looked identical to the peptide solution (unprecipitated) but with a lower absorbance unit (22 AU compared to 5 AU post-precipitation).
My question is, is this way of isolating peptides legit? And if I used FITC-NHS, would FITC also be precipitated by any chance? Will the peptide lose stability / increase cytotoxicity during TCA exposure? I am not using the peptide for functional studies, just trying to visualize cellular internalization.
- If this way makes no sense I will refer to other methods. Thanks for any suggestions.
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Success depends a little on the hydrophobicity of your peptide.
I'd try dry Et2O first, esp. if the volume of reaction is small, so all water gets can dissolve in the ether. If it should not work, remove the ether and try isopropanol or ethanol: Begin with small amounts, cool and centrifuge, then increase the alcohol concentration until your labeled peptide precipitates. Fluorescein will precipitate sooner or later, too (pH dependent).
If you try Adam's suggestion, keep all fractions until you know that the operation was successful. For concentrating the peptide, use precipitation as above. There is a high chance that the fluorescein gets trapped on the column and is moving *very* slowly (which is in your favor).
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I would like to prepare a calcium carboxylate. The procedure is overbasing the carboxylic acid with excessive Ca(OH)2 than bubbling CO2 through it to precipitate CaCO3. Can I just throw some pieces of dry ice into the mixture? Gas cylinder is hard to handle.
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Could you not put he solid CO2 into a container and bubble the gas through the calcium hydroxide solution?
Throwing the solid CO2 into the solution may simply freeze it