Science topic

Fixatives - Science topic

Fixatives are agents employed in the preparation of histologic or pathologic specimens for the purpose of maintaining the existing form and structure of all of the constituent elements. Great numbers of different agents are used; some are also decalcifying and hardening agents. They must quickly kill and coagulate living tissue.
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I'm trying to install packages for my masters thesis. When I try to install the package 'foreign' it works but when I try to run it, I receive the message:
Error in .helpForCall(topicExpr, parent.frame()) :
no methods for ‘foreign’ and no documentation for it as a function
How do I fix this? I have R version 4.4.0 on Mac OS 11 or 12 I believe.
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Pleun St Write exactly what you wrote to install it?
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Please send me pictures explaining how to simulate buckling of shear stresses in Abaqus 3D with hinged and fixed support ?
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It is easy. You should watch the tutorial videos on YouTube. Use LOAD and BOundary condition in ABAQUS.
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The wave function of quantum mechanics at a fixed point in space-time is simply a set of complex numbers. How does the set of these numbers relate to the geometry of the universe?
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After all, what can general relativity say about the geometry of the Universe if it is a foliation on a seven-dimensional sphere with a typical layer R^3×S^3? And quantum mechanics says that this is so.
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Please ask if you need additional information.
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It would be useful to know what concentration of DAPI you used and fore how long in order to troubleshot.
Additionally, there are some very bright spots present, and I'm uncertain whether they are cells or debris. If you have exposure set on automatic this could be causing your microscope to adjust gain or exposure time to this very bright sports leaving your nuclei underexposed. Could also be that you have your contrast set in automatic in the software in which you are seeing/exporting the images and again this bright spots are interfering. If the second is true, then you would only need to adjust your contrast before exporting, overexposing those dots but correctly exposing your cells.
Hope this helps!
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Hi everyone,
I want to Apply Tests for Special Causes in p-chart, but the sample size for each group is different. So I don’t have a fixed UCL and LCL. Just a question can I apply Tests for Special Causes? Can I calculate index when I don’t have a fixed LCL and UCL.
Thanks,
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This is the raw data. Please understand it according to the P diagram method
Product P chart for non-conforming products within one month, one sample will be taken every day within one month
Samples were taken and the number of non-conforming products was checked, with a total of 26 days of data collected.
The data is as follows:
Inspection quantity Unqualified quantity (nP)
158 11
140 11
140 8
155 6
160 4
144 7
139 10
151 11
163 9
148 5
150 2
153 7
149 7
145 8
160 6
165 15
136 18
153 10
150 9
148 5
135 0
165 12
143 10
138 8
144 14
161 20
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Hi everyone, I'm trying to extract fungal DNA from wheat common bunt using chelex100 and I've tried several different protocols without any success. I've used different concentrations of chelex100 (5%, 10%, 20%) with different ways of heating (heat block, water bath, boiling water) and different timings (2x 15 mins, 1x 30 mins plus 1x 15 mins, 2x 20 mins). Only 2 things were fixed in all my tries, 1st thing is that I dissolved chelex100 in double distilled injection water and 2nd thing is that I centrifuged the complex at 13000 rpm for 1 min every time it needed centrifugation. I'm not sure what am doing wrong, Like should I try dissolving chelex100 in any specific buffer or something? or should I change my centrifugation speed and time? or do I need to add anything to the complex in different steps?
I'd appreciate if you take the time and kindly answer my question.
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We use Chelex 100 dissolved in TE Buffer (pH8) to isolate DNA from gram positive spore forming anaerobic bacteria. We suspend 1 bacterial colony in 40uL 10% Chelex. Heat at 100C for 15 minutes. Centrifuge at 18000g for 1 minute. Dilute the supernatant 10-fold in TE buffer. DNA suitable for PCR as well as NGS. Hope it helps.
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Hi users,  I want to create an itp file for my ligand (ligand with ruthenium) complex, im using MCPB.Py for generating itp for my structure during the process i got the following error kindly please help. MCPB.py -i dna.in -s 3 The input file you are using is : dna.in The following is the input variable you have: The variable ion_ids is :  [1201] The variable ion_info is :  [] The variable ion_mol2files is :  ['Ru.mol2'] The variable original_pdb is :  complex_fixed_h.pdb The variable add_bonded_pairs is :  [] The variable add_redcrd is :  0 The variable additional_resids is :  [] The variable anglefc_avg is :  0 The variable bondfc_avg is :  0 The variable chgfix_resids is :  [] The variable cut_off is :  2.8 The variable force_field is :  ff19SB The variable frcmod_files is :  ['LIG.frcmod'] The variable gaff is :  1 The variable group_name is :  dna The variable ion_paraset is :  12_6 (Only for the ions using the nonbonded model). The variable large_opt is :  1 The variable lgmodel_chg is :  -99 The variable lgmodel_spin is :  -99              -99 means program will assign a charge automatically. The variable naa_mol2files is :  ['LIG.mol2'] The variable scale_factor is :  1.0              ATTENTION: This is the scale factor of frequency. The              force constants will be scaled by multiplying the square              of scale_factor. The variable smmodel_chg is :  -99 The variable smmodel_spin is :  -99              -99 means program will assign a charge automatically. The variable software_version is :  gau The variable sqm_opt is :  0 The variable water_model is :  OPC The variable xstru is :  0 ****************************************************************** *                                                                * *======================RESP Charge fitting=======================* *                                                                * ****************************************************************** ***Generating the 1st stage resp charge fitting input file... ***Generating the 2nd stage resp charge fitting input file... ***Doing the RESP charge fiting... =========================Checking models========================== ***Check the large model... Good. The charges and atom numbers are match for the large model. Good. There are 27 atoms in the large model. ***Check the standard model... Traceback (most recent call last):   File "/home/saranya/amber20/bin/MCPB.py", line 692, in <module>     resp_fitting(stpdbf, lgpdbf, stfpf, lgfpf, mklogf, ionids, ff_choice,   File "/home/saranya/amber20/lib/python3.9/site-packages/pymsmt/mcpb/resp_fitting.py", line 521, in resp_fitting     raise pymsmtError('Error: the charges and atom numbers are mismatch ' pymsmt.exp.pymsmtError: Error: the charges and atom numbers are mismatch for the standard model!
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Did you find an answer for this? Im having this same issue.
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Hello,
I am planning to conduct an experiment to identify bacteria bound to IgG by flow cytometry. I aim to focus on live bacteria, so I intend to use the LIVE/DEAD BacLight Kit (Syto9 and propidium iodide) to confirm I'm examining live bacteria. Since I need to fix the samples before acquisition on the flow cytometer, my questions are:
  1. Is it possible to fix samples when using the LIVE/DEAD BacLight Kit?
  2. Should I perform IgG staining before or after the LIVE/DEAD staining?
Thanks in advance,
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Thank you so much Kais Khudhair al Hadrawi for your answer!
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How to fix the mentioned issue in Material Studio Software?
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Dear, sadia
let me konw that is your target at first or what you willing to do..because the above attached file is look like a pop-up message..therefore we can't understand properly, what kind of issues had you facing or did you face this issues while calcuating something...?
Best Regard
Vikrant Singh
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Hello Everyone,
It is part of the dogma of verbotonalism that if you fix the intonation of an L2 you also automatically fix the pronunciation of all/most/many individual sounds. While I think from observation and results reported over the years in many places that this is true, I still have a question.
Has any study been done *with hard statistical data* to demonstrate that this is so? I am looking for something other than impressionistic data. And if such studies exist, please provide the citation if possible. I have no memory of such studies.
Since the Revue de Phonétique Appliquée disappeared a huge amount of publications on VT has also disappeared. I will try a closer look at Govor but I thought I would ask anyway.
Thank you!
Andrew
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Great answer. No one would/should disagree with you though current common practice still tends to prioritize segmental study over suprasegmental study. When I say it is part of the dogma of verbotonalism I mean that it is actually one of the fundamental principles of the theory which seems to have worked in specific cases in the past. And people keep repeating this as though it were an ultimate truth and wholly-established. Of course, theoretically and even/especially from the perspective of acoustic phonetics, this makes perfect sense. Regrettably, though, in modern times, I cannot find hard data-driven evidence as to the impact of intonation training on the development of the pronunciation system as a whole. Perhaps this is due in part to the disappearance of some of the basic sources of information from the past such as the Revue de Phonétique Appliquée and the lack of evidence in some of the major languages, particularly English. Most writing has been in Serbo-Croat, French and Spanish with a restating of the theory from the American perspective with the work of Carl W. Asp. There are many studies still left to be done in relation to verbotonal theory and that would open up new avenues not only in pronunciation studies but in relation to the the interface between perception and learning - which is an under-researched area in education generally and language education in particular.
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Hello sir,
I want to apply uplift pressure at the dam base in a gravity dam structure with a fixed base case.
I created step- Gravity - Hydrostatic - Uplift.
& I fixed base of the dam by fixing it in U1, U2 direction.
When I apply uplift pressure with the fixed base case - the model completes the analysis, but there is no difference between the results of Hydrostatic and Uplift pressure step.
And if I release the U2, than the model does not complete the analysis and shows error "Excessive distortion at a total of 5 integration points in solid (continuum) elements".
Please guide me, How to resolve this problem and to apply Uplift pressure... It would be really helpful to me and appreciated a lot by me.
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Thank you sir for your response....
I have one other query...
how to create Lysmer – Kuhlemeyer’s viscous boundary in Abaqus software for foundation?
Please help me out...
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My citations used to appear on the profit;e page now it is zero
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I had observed the same from yesterday. It has been corrected now by researchgate.
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I have a question about some weird nuclei I see while imaging. I'm sorry if this isn't the best place to write it!
One image has bad, "shattered"-looking nuclei from dentate gyrus.
The other image has healthy nuclei from CA1.
I end up in some experiments with really terrible looking DAPI with "shattered" nuclei. Sections with this type of DAPI are highly correlated with really bad FISH staining as well. It seems like most of the tissue integrity is lost in general.
I've seen this before, but not enough times to know what step of tissue collection and processing could cause it. I don't *think* this is purely a cryosectioning issue.
Does anyone have any guesses for what could cause this issue? I'm guessing I can't be the first person to run into this!
Tissue processing
I am imaging coronal brain sections from mouse tissue that is flash frozen immediately after dissection. In this case this is imaging dentate gyrus, where nuclei should be exceptionally dense. 20 um cryosections are immediately placed onto Superfrost glass slides and stored at -70 (in this case for ~2 weeks).
Sections are fixed with 4% PFA on the slide and then dehydrated with serial EtOH incubations of 50%, 70%, and 100% for 5 minutes each. Then sections go through the RNAscope smFISH protocol, at the end of which they are stained with DAPI for 30 seconds.
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Looks like an artifact from slow freezing of the tissue causing ice crystal formation in the cells and subsequent expansion and destruction. I've seen this many times, mainly from tissues obtained already frozen elsewhere. Hopefully, you are sure that the flash freezing is being done correctly.
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Today I found a very strange thing in my research gate account..it showing Citations -0..However, I saw more than 150 Citations last week..Dose anyone know how to fix it ??
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I am working on termites and doing in situ hybridization but at the end, I can't see cells in specimen slides. my question is how to maintain the structural integrity during fixation or whole process can influence cell structure. I think fixation is the main part of hybridization. I am using 4% paraformaldehyde at 4degree to fix termite for 3-4 hours then gradient dehydration with ethanol. if any suggestions it would be highly appreciated.
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for any colleague reading your request it would be fine, really informative and therefore also important for a decision, how one can help with regard to your problems if you would add at least 'little' additional information about your performing in-situ-hybridization and adding - perhaps and if available - (an) image(s) of the final appearance on slides...
Further (always informative and sometimes recommended) readings (out of many more);
ZHU et al, 2021: Effects of fixation on bacterial cellular dimensions and integrity [iScience. 2021 Apr 23; 24(4): 102348] cf. also:
(=https__://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066382/ NB: prior to 'execution' - when copying that URL into your browser - delete the two undersigns__ in between http and ://www....) or directly on NIH-NCBI-PubMed-website (4,6 MB) :
https__://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066382/pdf/main.pdf
(NB as before);
Biotechne(R)
What is the Significance of Fixation: cf.
ETHOS BioSciences:
Choosing the Right Fixative
Steps to Better ISH and more... by Geoffrey Rolls, BAppSc, FAIMS, cf.:
Best wishes and regards, W.H.M.
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A growth mindset refers to the belief that individuals can develop their abilities through dedication and hard work. Those with a growth mindset perceive challenges as opportunities for growth and regard failure as a natural aspect of the learning journey.
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The answer to Your question cannot be unambiguous and suitable for all cases. Everything depends greatly on the development of consciousness of the student himself. Thus, the answer to your question may look like this: for 5-10% of students the answer is “yes”; for 65-70% of students the answer is “possible with efforts on the part of the student and teacher”; for 20-30% of students the answer is “no”.
I recommend that you study the works of Doctor of Biological Sciences, Professor Sergei Savelyev(Сергей Савельев) dedicated to the morphology of consciousness.
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I'm not sure how to interpret or fix the sample so that it creates a normal band. I used Percoll Gradient with density gradients to generate the questionable band. It's supposed to represent basolateral membrane fraction, and most people mentioned that the sample preparation is not good enough, but I'm not sure how I can make it "good enough".
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Here are some concise tips to improve the quality of bands in your Percoll gradient:
1. Optimize Percoll Concentration: Experiment with different concentrations to find the optimal gradient for separating the basolateral membrane fraction.
2.Sample Preparation: Use effective techniques like homogenization or sonication to isolate the membranes efficiently.
3.Starting Material Quality: Ensure high-quality cells or tissue free from contamination.
4.Centrifugation Parameters: Adjust speed and duration to optimize separation.
5.Marker Proteins: Include specific markers to confirm the presence and purity of the fraction.
6.Gradient Fractionation: Collect and analyze fractions separately to locate the basolateral membrane fraction.
7.Quality Control: Use assays to confirm membrane protein presence and fraction purity.
8.Consult Literature: Look for optimized protocols and techniques in relevant research papers.
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Log(output) file preview is as below:
Search did not lower the energy significantly.
No lower point found -- run aborted.
Error termination via Lnk1e in /opt/g16/l508.exe
Job cpu time: 0 days 14 hours 4 minutes 28.9 seconds.
Elapsed time: 0 days 2 hours 54 minutes 57.4 seconds.
File lengths (MBytes): RWF= 138 Int= 0 D2E= 0 Chk= 8 Scr= 1
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This error occurs when SCF not converged when QC method was used.
To solve this problem, this action is necessary: Delete keywords like SCF=QC, SCF=XQC, SCF=YQC and submit to calculation again.
Note that calculations may be time-consuming and require powerful systems. I recommend the services of MolQube.com. They provide you with as many cores and RAM as you need. You do not get involved in software installation. They help you in creating input and extracting data. You can contact them by email: [email protected]
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Hello,
I am using movestay command for ESR model analysis, but I get an error message.
Can anyone help me please?
movestay (ln_wage = $x), select(union= $x msp) vce (robust)
The error message is:
Fitting initial values .....initial vector: copy option requires either a matrix or a list of numbers
r(198);
Thanks in advance for your kindness
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I assume 'map' is the instrumental variable, thus, use the following:
movestay (ln_wage = $x), select(union= msp) robust cluster(ID)
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Why am I getting a Parsing error when I upload an article? How do I fix it?
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A parsing error typically occurs when the system attempting to read or interpret the uploaded article encounters difficulties understanding the format or structure of the content. Here are a few common reasons why you might be encountering a parsing error:
  1. Incorrect File Format: Ensure that the file you're uploading is in a compatible format. For example, if you're uploading a text document, it should ideally be in plain text (.txt), or if it's a structured document like HTML or XML, make sure it adheres to the syntax rules of that format.
  2. Formatting Issues: Check for any irregularities in the formatting of the document. Sometimes, special characters, improper indentation, or unexpected line breaks can confuse the parser.
  3. Unsupported Characters: If the document contains characters that are not supported by the parser, it might result in a parsing error. Ensure that the document only contains characters supported by the system.
  4. Corrupted File: It's possible that the file itself is corrupted. Try opening the file locally on your computer to see if it opens without any issues. If it does, then the problem might lie with the system you're uploading it to.
  5. Software Version Compatibility: Sometimes, parsing errors can occur due to compatibility issues between the software version used to create the document and the one being used to parse it. Make sure the software versions are compatible.
  6. Insufficient Permissions: If you're uploading the file to a server or a platform where you don't have sufficient permissions, it might result in a parsing error. Ensure that you have the necessary permissions to upload files.
  7. Server or System Errors: Occasionally, parsing errors can occur due to temporary issues with the server or the system itself. In such cases, try uploading the file again after some time.
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I already did some activation experiment to observe expression of CD40, CD86, CD80 and MHC with macrophage 264.7 and dendritic cells (DC2.4). I treat these cells with positive control LPS and therapeutic nanoparticles or bare nanoparticles. So, once I collected the cells, washed them and fixed with 4% paraformaldehyde (pH=6.9) or 5% Formalin in PBS. But I observed that I was losing cells with washing, fixing and post-fixing washing steps. My events/second in the flow cytometry were very low. I was thinking what if I don't fix the cells and I was wondering what was the purpose of fixing?? If I don't fix the cells, should that affect the results negatively? Thanks
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Hello Sudip Kumar Dam,
If you don't want to fix the cells, then you should try to analyze the cells on the flow cytometer as soon as possible, within an hour's time. If the cells are not analyzed in the flow cytometer immediately after antibody staining, then you may have to fix the stained cells with 1-4% PFA, 20 mins at 4°C. For extended storage as well as for greater flexibility in planning the time on the flow cytometer, you will have to resuspend the cells in 1-4% paraformaldehyde to prevent deterioration.
For surface antigens, you should stain the cells and then fix, if you are not going to carry out the analysis immediately. However, if your target is intracellular, you’ll have to fix/permeabilize the cells prior to staining anyway allowing the antibody to reach its target. The controls will require fixation using the same procedure.
Fixation is good for cells labeled by fluorochrome-conjugated antibodies to membrane antigens. It will stabilize the light scatter and labeling for up to a week in most instances, allowing you to be more flexible in scheduling your flow cytometer time. Also, it inactivates most biohazardous agents.
Best.
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Why are numbers and shapes so exact? ‘One’, ‘two’, ‘point’, ‘line’, etc. are all exact. But irrational numbers are not so. The operations on these notions are also intended to be exact. If notions like ‘one’, ‘two’, ‘point’, ‘line’, etc. are defined to be so exact, then it is not by virtue of the exactness of these substantive notions, but instead, due to their being defined so, that they are exact, and mathematics is exact.
But on the other side, due to their being adjectival: ‘being a unity’, ‘being two unities’, ‘being a non-extended shape’, etc., their application-objects are all processes that can obtain these adjectives only in groups. These are pure adjectives, not properties which are composed of many adjectives.
A quality cannot be exact, but may be defined to be exact. It is in terms of the exactness attributed to these notions by definition that the adjectives ‘one’, ‘two’, ‘point’, ‘line’, etc. are exact. This is why the impossibility of fixing these (and other) substantive notions as exact misses our attention.
If in fact these quantitative qualities are inexact due to their pertaining to groups of processual things, then there is justification for the inexactness of irrational numbers, transcendental numbers, etc. too. If numbers and shapes are in fact inexact, then not only irrational and other inexact numbers but all mathematical structures should remain inexact except for their having been defined as exact.
Thus, mathematical structures, in all their detail, are a species of qualities, namely, quantitative qualities. Mathematics is exact only because its fundamental bricks are defined to be so. Hence, mathematics is an as-if exact science, as-if real science. Caution is advised while using it in the sciences as if mathematics were absolutely applicable, as if it were exact.
Bibliography
(1) Gravitational Coalescence Paradox and Cosmogenetic Causality in Quantum Astrophysical Cosmology, 647 pp., Berlin, 2018.
(2) Physics without Metaphysics? Categories of Second Generation Scientific Ontology, 386 pp., Frankfurt, 2015.
(3) Causal Ubiquity in Quantum Physics: A Superluminal and Local-Causal Physical Ontology, 361 pp., Frankfurt, 2014.
(4) Essential Cosmology and Philosophy for All: Gravitational Coalescence Cosmology, 92 pp., KDP Amazon, 2022, 2nd Edition.
(5) Essenzielle Kosmologie und Philosophie für alle: Gravitational-Koaleszenz-Kosmologie, 104 pp., KDP Amazon, 2022, 1st Edition.
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We are performing an experiment to detect radon with the help of Emanatory technique and we are not able to fixed the right EHT voltage for Lucas cell PMT. Can anyone suggest how to proceed?
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The operating voltage for a scintillation detector can vary depending on several factors, including the specific type of scintillator material used and the desired performance characteristics. However, typical operating voltages for scintillation detectors can range from several hundred to several thousand volts.
For example, sodium iodide (NaI) scintillation detectors, which are commonly used in gamma-ray spectroscopy, typically operate at voltages ranging from around 600 to 1500 volts. Other scintillator materials may have different optimal operating voltages.
It's important to consult the specifications provided by the manufacturer of the scintillation detector being used to determine the recommended operating voltage for that particular device. Additionally, experimental calibration and optimization may be necessary to achieve the best performance for a specific application.
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Dear colleagues,
I am encountering an issue with our recently donated Sciex API 4000 LC-MS/MS system. As indicated in the attached data, I am not receiving any signal above 175 m/z. Has anyone else faced a similar issue, or does anyone have insights into the possible reasons behind this? Your suggestions and expertise would be highly appreciated. Given budget constraints, I am exploring whether I can troubleshoot and resolve this without calling in an engineer.
Thank you for your assistance.
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Hello,
In the many years of working on the API4000 - a wonderful and robust instrument which has served me and many research collaborations well - I have seen a number of issues. You are missing a variety of rather important information in order to provide adequate advice .... but .... nonetheless I will try to help, if I can ... One: Have you adequately cleaned Q1 and changed the electrode? You do not state which mode of ESI you are using (+) versus (-) mode. You may be experiencing a form of charging or an issue with one of the boards. You may have no other choice but to call the engineer for service. When was the last time you had a PM? I certainly understand the need to keep costs down ... hope that helps, at least somewhat - best - MFW
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Up to half of tropical forestland cleared for agriculture isn’t put to use, research shows!
  • Agriculture is the primary driver of tropical deforestation, accounting for 90% or more of forest loss, yet researchers have found that up to half of total land cleared is not put into active agricultural production.
  • The gap between what’s cleared and what’s used for agriculture shows that “we have to fix agriculture and we have to fix deforestation,” according to one of the researchers.
  • Tropical deforestation is a major contributor to global greenhouse gas emissions and climate change, but the research shows there is no simple fix, as humanity’s increasing food needs coincide with the need for conservation.
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To reverse the trend of tropical deforestation caused by agriculture, we can implement several strategies:Agroforestry: Encourage farming practices that integrate trees with crops and livestock. This approach helps maintain soil health, provides additional income sources for farmers, and reduces the need for clearing forests for agriculture.Sustainable farming practices: Promote methods such as conservation agriculture, organic farming, and precision agriculture, which prioritize soil conservation, reduce chemical inputs, and optimize land use efficiency.Land-use planning: Develop and enforce land-use policies that protect forests and prioritize sustainable land management practices. This includes zoning regulations, protected area designations, and incentives for sustainable land use.Investment in alternative livelihoods: Support rural communities dependent on agriculture with alternative income opportunities such as eco-tourism, sustainable forestry, and non-timber forest products.Certification programs: Encourage adoption of certification schemes like Rainforest Alliance and Forest Stewardship Council (FSC) which promote responsible land management practices.Technology and innovation: Invest in research and development of technologies that improve agricultural productivity while minimizing environmental impact, such as precision farming, drought-resistant crops, and agroecology.Education and awareness: Raise awareness among consumers about the environmental impacts of agriculture and empower them to make informed choices that support sustainable practices.
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هل تعلم ان الصلاة لها هدف ثابت ونهائي؟
تحتوي
الكلمة الموحدة
على أضواء يمكننا جميعًا رؤيتها وتجريدها وتطبيقها في جميع مجالات المعرفة.
حيث الأضواء أكثر من
+ 50 اكتشافًا،
+ 300 ابتكارات حقيقية، و
+ مئات من البيانات المعرفية الجديدة.
موضوعنا اليوم هو الهدف النهائي والأخير لأي صلاة
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السلام علیکم و شکرا من هذا السوال - طبعا للصلوة تاثیرات کثیره و عندما نقف امام ربنا نجد من نستطیع ان نتکلم معه دون ای واسطة و نطرح کلما نرید منه نجد من هو قریب من نجد من هو اقرب منا من حبل الورید نجد حلاوة‌الذکر و المناجاة و کل هذه الحالات مجموع فی الصلوة بشرط ان نتذکر امام من نقف و طبعا لا نستطیع ان نقول او نعین هدفا واحدا للصلوة بل طبعا یکون له اهداف کثیره و شکرا من جدید
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I did IHC using fluorescent labeled secondary antibodies to detect astrocytes with GFAP marker. My sample was fixed frozen mouse brain tissue streatum region. I saw fluorescence in my sample treated without the primary antibody. I noticed that this fluorescence was exactly overlapped the DAPI staining. I used alexafluor488 secondary antibody and mounting media with DAPI. I attached the picture with my staining. My secondary antibodies were at a 1:1000 dilution.
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Just for thoroughness, could be good to take a look at a unstained sample using the same imaging parameters as well.
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I am doing CLSM (confocal laser scanning microscopy) of nafion film. I am doing z-scanning. But i am having problem in setting the Z-interval.
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Hello, z interval: distance between two optical slices (step size of z motor: min.100 nm, Axioplan 2 imaging: 50 nm.
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For some reason Researchgate combined my citation list with that of Michael D. Baer
which could mislead those who are interested in one of these lists.
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You may fix it by separating the two citation lists from top to bottom
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I am trying to cut mouse brain fixed in 10% formalin for 24 hours embedded in OCT after sucrose treatment. The samples sink in the sucrose, so we don't think that is the problem and the tissue looks completely fixed based on color, firmness, etc. The issue is that our samples splinter when cut. I have heard this is because the sample is too cold, but we have tried at a range of temperatures and the problem persists. I have also tried adjusting blade angle and changing the blade, but this did not seem to help.
Does anyone have any suggestions or a good protocol to follow?
Thanks,
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Usually, when the tissue is overly brittle/hard, splinters may occur. Even though fixed tissues are more stable and resistant to degradation, it will increase the hardness of the tissues.
You can try reducing the formalin conc. or fixation time if the fixation step is mandatory for your application.
Otherwise try a fresh tissue-cryosectiong (without fixation), if possible.
Please keep in mind that, the brain tissues are very fragile and heterogeneous and are usually difficult for cryosectioning. If your application permits routine paraffin-embedded sectioning, you can preserve a good morphology.
Thanks.
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I have a problem with running my logistic regression. When I run my analysis, I get really strange values and I cannot find anywhere how I can fix it. I already changed my reference category and that led to less strange values but they are still there. Also, this only happens to two of my eight predictors. These two predictors have multiple levels/categories.
Can someone explain to me what's wrong and how I can fix it?
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You are using categorical independent variables. How could there be a logistic relationship???
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The URL assigned for my researchgate landing page is incorrect - it has my name wrong. How do I correct it to reflect my correct name?
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It does not seem possible to change the URL "by hand". My observation is that RG's algorithm compiles the URL from the first and the last names, adding a number in case of dublicate names of users. Cf. the URL of my account: https://www.researchgate.net/profile/Wolfgang-Dick-3
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I am running protein samples on SDS-PAGE that are tagged with fluorophores. If I place the gel in a destain solution of 60%water/30%methanol/10% acetic acid, the chemistry reverses and I lose the fluorophore. Is there an alternative storage solution I can use to get my gel to the imager to capture the fluorescence without chemical fixatives? After imaging, I then proceed to Coomassie Blue staining in acetic acid and methanol, at which point I am not worried about losing the fluorophore.
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i'm agree with Paul Rutland
you can just store the gel in milliQ water. it is stable.
Staining and destaining with methanol/acetic acid is the old way to acheive fast results but you can stain and destain gels also with water based stains.
you can find an example of this in the following video on my blog:
best
Manuele
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Hello experts from Research Gate,
I am struggling with staining live E.coli with Hoechst 33342 and FM 4-64FX. The fluorescent images were too dim even at high concentration of the fluorescent dyes (2-10 times higher than the concentration recommended by Invitrogen). And I had to acquire images at high exposure time (1000-4000ms) which led to photobleaching, high phototoxicity, high noise and extremely slow image acquisition. It seemed that Hoechst could not penetrate all the live E.coli cells uniformly (a few were bright and many were too dim).
Could you please have a look at my protocols and point out the problem of the protocols.
Protocol 1. Staining with Hoechst 33342 (or SYTOX Green):
  1. Grow E.coli in LB broth to reach OD600 ~ 0.3 (see note 1)
  2. Aliquot 1mL of bacterial suspension to a microcentrifuge tube
  3. Centrifuge at 12,000 rpm for 2 minutes
  4. Remove supernatant
  5. Resuspend in 20uL of Hoechst 33342 10ug/mL (or/and SYTOX Green 5uM/mL) working solution (see note 2)
  6. Incubate at room temperature, in dark, for 10 minutes (see note 3)
  7. Wash 03 times with PBS
  8. Centrifuge at 12,000 rpm for 2 minutes and remove supernatant
  9. Resuspend in 20uL of Prolong live antifade reagent
  10. Incubate at room temperature, in dark, for 15 minutes. Go to step 12 for imaging or step 11 for fixing
  11. Centrifuge at 12,000 rpm for 2 minutes and remove supernatant. Resuspend in 20uL of paraformaldehyde 4%. Incubate at room temperature, in dark, for 10 minutes. Go to step 12 for imaging on agarose pad
  12. Imaging: gently spread 2uL of bacterial suspension onto a small piece of nutrient agar placed on a microscopy slides. Airdry for 1-5 minutes. Place a coverslip on top. Ready for imaging. 
Protocol 2. Staining with FM 4-64 FX after staining with Hoechst (or SYTOX Green):
  1. Start from step 10 of protocol 1
  2. Centrifuge at 12,000 rpm for 2 minutes and remove supernatant. Resuspend in 20uL of of FM 4-64FX 5ug/mL (see note 4)
  3. Incubate at room temperature, in dark, for 5, 10, 15, or 20 minutes (see note 5).
  4. Go to step 6 for imaging or step 5 for fixing
  5. Centrifuge at 12,000 rpm for 2 minutes and remove supernatant. Resuspend in 20uL of paraformaldehyde 4%. Incubate at room temperature, in dark, for 10 minutes. Go to step 6 for imaging on agarose pad
  6. Imaging: gently spread 2uL of bacterial suspension onto a small piece of nutrient agar placed on a microscopy slides. Airdry for 1-5 minutes. Place a coverslip on top. Ready for imaging. 
Protocol 3. Staining with FM 4-64 FX alone:
  1. Start from step 4 of protocol 1
  2. Centrifuge at 12,000 rpm for 2 minutes and remove supernatant. Resuspend in 20uL of of FM 4-64FX 5ug/mL (see note 4)
  3. Incubate at room temperature, in dark, for 5, 10, 15, or 20 minutes (see note 5).
  4. Go to step 6 for imaging or step 5 for fixing
  5. Centrifuge at 12,000 rpm for 2 minutes and remove supernatant. Resuspend in 20uL of paraformaldehyde 4%. Incubate at room temperature, in dark, for 10 minutes. Go to step 6 for imaging on agarose pad
  6. Imaging: gently spread 2uL of bacterial suspension onto a small piece of nutrient agar placed on a microscopy slides. Airdry for 1-5 minutes. Place a coverslip on top. Ready for imaging. 
################
Note:
  1. I have also diluted the bacterial suspension at 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, 1/256
  2. I have tried Hoechst at different concentrations including 10, 20, 50, 100ug/mL
  3. Incubation time also was 15, 20, 30 minutes
  4. Also FM 4-64FX at 20 and 100ug/mL
  5. Also on ice
  6. Fluorescent dyes were prepared in water (Sigma) or PBS and stored in dark microcentrifuge tubes at -20oC. All the dyes were purchased from Invitrogen
  7. The microscope was Nikon Ni-e with mercury lamp, DAPI filter (Ex: 375/28, Em: 460/60) for Hoechst, FITC (Ex: 480/30, Em: 535/45) for SYTOX Green, and TRITC (Ex: 540/25, Em: 605/55) for FM 4-64FX
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May consider using Permai fluorescence dye.
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Hi every one
I have a model in Abaqus standard with Heat transfer. When I restart this model , Abaqus exit with this error:
"Unable to open the file <rank=0,arg_name=E:\ABQ
Model>Job-2.mdl"
How I can fix this error?
Thanks
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The disk space is not enough to handle it.
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The way in which the contractual dispute was formed was that the fixed obligations of one party made it an economic force of the contract that could not be resisted, while the immutability of these obligations made the other party something rigid. This constitutes “a fundamental loophole in the contract, to prevent the fragmentation of the contract’s economy.”
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Entering into a contract should be through mutual agreement of the parties.At no point should a person unduly influence another into an engagement. It would therefore suffice that consent is sought. Such contracts should be treated as repudiated.
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I am writing a word document, using my Mac. When trying to insert a citation from Mendeley I get a Microsoft message saying "Citation/Bibliography is wrongly placed in index area, please delete the placed citation/bibliography in index area."
What should I do?
Many thanks
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I had the same problem. The solution was to hit "ALT + F9" and find some stray piece of code in the text in which there was a "{ ADDIN ..... "
After I deleted it, it was good to go. I learned it from this post:
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What does DAMASK runtime interrupt with the error "max number of cut back exceeded, terminating" mean, and how do I fix this problem?
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Jcak Sun Time step can be controlled in load.yaml file.
you have two variables , t -> time , N -> increments.
t/N is the time step. So you can adjust (increase) your N.
Also what Achal H. P. suggested, you can increase maxCutBack number in the numerics.yaml file.
None of the above guarantees convergence, if the underlying constitutive behavior is the problem
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Even fixing memory limit and processor unit does not work.
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thank you sir @Massimiliano Arca
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Hi all,
I am a PhD candidate trying to model a fluidized bed reactor with liquid-solid fluidized bed reactor. There is no gas. The solid fraction is not fixed at the moment so for maximum flexibility of solid fraction and for ease of using the code (easy to understand and modify). Which opensource LBM software would you all suggest? Thanks in advance!!
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I suggest you take a look at OpenFOAM. It is open-source and it has fluidized bed reactor problem in the tutorial. I am no expert in the field but I have seen a tutorial with this title.
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Hlo I am trying to get kinetics of methanol to dimethyl ether kinetics on hzsm-5 si/al = 40 catalysts at 160 deg c I was unable to reach zeroth order kinetic regime. I doubt that the reaction will become mass transfer control before it reaches zero order kinetics. Please let me know what should be the partial pressure of methanol when the reaction reaches zero order . I am also using a fixed bed catalytic reactors where i change the flow rate of methanol to change the partial pressure and i am also injecting nitrogen along with the methanol where i am changing the methanol flow rate. Please let me know is this an ideal practice for getting kinetics. Please let me know
Thank you.
Vignesh
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Hi Vignesh,
Actually I don’t think that pressure has a great influence on the reaction, since methanol dehydration occurs without a change in the number of moles. I would work on catalyst particles’ size, finding a compromise between excessive pressure drops and mass transfer limitations. Moreover, I would try to increase temperature: it is a bit low and, therefore, there could be kinetic limitations, rather than thermodynamic ones.
I hope I have been a help to you,
Antonio
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After performing PCR, I ran electrophoresis, but on agarose the results showed some rather blurred samples. I wanted to know the cause and how to fix this situation. Please note that the chemicals and dyes are normal because the positive control shows a clear band.
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How many cycles of pcr are you running and how much dna (ng) are you amplifying in each pcr reaction?
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Hello i tried to calculate the size of cristallites with ORIGIN drawing a line passing by the middle of each peak . the problem is that there are some peaks where the line does not pass by them how can i fix this .If there is another methods to calculate the size of cristallites ?
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you have to do peak profile fitting, and then determine/note the middle of the peak. Try to do Reitveld refinement of your XRD pattern, once you achieve an acceptable value of goodness of fit, and the pattern fits to the structure, then lood at the d-spacings, and calculate your 2theta values for your crystallalite/grain size distribution/analysis.
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I thawed these adherent cells 3 weeks ago, I don't remember when I found this contamination,
Contaminants and cells do not grow in the same layer and contaminants appear to be irregular or filamentous,
the cells are growing well, and the medium is always clear,
the blurred dots and lines are because the microscope is not clean, that is not contamination.
but I wish to fix this problem before it becomes worse,
If anyone has any suggestions, that would be a great help to me, thanks a lot.
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The pictures do not show anything relevant.
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I have to remove OCT from the tissue completely and fix the OCT-removed tissue in paraffin. Please suggest the best way.
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Hi Omar, Thanks for explaining and suggesting the OCT removal and fixation by Paraffin.
We Paraffin embedded tissues but they were ruined, so we are trying to retrieve tissue from OCT and fix with Paraffin.
I will follow your suggestion.
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I need to do fluorescent microscopy using Propidium Iodide. I initially fixed my cells with 4% paraformaldehyde and saw red stain in Control cells. It turns out PFA is cell permeable. So if anyone has a protocol using Ethanol as a fixative please do share.
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Thank you, do you have a specific protocol or a reference I can read up from?
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A large polymeric membrane was recovered with graphene oxide. I would like to know where the graphene oxide fixed and how is the distribution.
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You can use TEM technique to confirm the presence of GO sheets in polymer network. For further confirmation, Implement Raman technique which will give you 100% conformation about the presence of GO inside polymer network.
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Has anyone purchased or used the table top BD Facs melody cell sorter? Our lab purchased one 1.5 years ago and it has been the most frustrating machine ever. The stage locks up, techs have to come out every 2-3 months to fix something and reboot the software, etc. I am trying to ascertain other researchers experiences , if any, with this model. I believe we have an absolute lemon but I want your feedback.
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Hi Leah,
my feedback may be a bit late. But I've slowly made friends with this machine. :-) I think the software is simpler than BD Diva, but you can't change much about the basic settings. Unfortunately, a technician from the company has to come for this. Otherwise, it's going very well. Personally, I clean the Flowcell excessively. This means that I perform up to 8x "FlowCell-Washes" before the CS&T beads runs. And since our machine is not in continuous operation, I always perform the long-term shutdown and then the machine is in EtoH.
Are your experiences with BDMelody are better now?
Best Claudi
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Neutral buffered formalin is best fixative in histopathology. But if by any chance it gets yellowish so what all shall we do to get rid of this problem in laboratories?
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Dear Dr. Amit Vishen,
The neutral buffered formalin (NBF) must have polymerized. Have you prepared 10% NBF in-house?
If yes, then please note that 10% neutral buffered formalin is a solution of 10% formaldehyde in sodium phosphate buffer containing up to 1.5% methanol.  
Methyl alcohol acts as an inhibitor of formaldehyde and prevents polymerization. Therefore, a small amount of stabilizer like methanol is usually added to suppress oxidation and polymerization.
Usually, commercial-grade NB formalin solutions contain methanol as an additive in order to prevent formaldehyde polymerization over time.
Regards,
Malcolm Nobre
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An example can help better to understand and solve this.
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Heteroscedasticity in regression is generally not a bug, it's a feature.
See Knaub, J.R., Jr.(2021), "When Would Heteroscedasticity in Regression Occur?"  Pak. J. Statist., Vol. 37(4), 315-367, https://www.pakjs.com/
In the references are a paper on "essential" heteroscedasticity, which is heteroscedasticity to be expected, and a paper on "nonessential" heteroscedasticity, which would be problematic sources of a kind of artificial heteroscedasticity. Generally, it would appear that if you do not have (essential) heteroscedasticity, you may have model specification, stratification or grouping, and/or data quality problems.
The paper above contains examples.
Also another reference in the article above is on how to measure the coefficient of heteroscedasticity. Heteroscedasticity in regression is a matter of degree, not yes or no, and thus hypothesis tests are basically useless here. If one says you have heteroscedasticity, then how much? If not, why not, and what was the threshold? Also, what do you do about it? A transformation may help improve this, but also may muddy any interpretation. I generally do not recommend them. But if you model using weighted least squares, then determining an appropriate coefficient of heteroscedasticity to use will then be used to determine regression weights. Unfortunately, as Ken Brewer said in his book, referenced in my article above, it usually takes a large sample size to obtain a good estimate of the coefficient of heteroscedasticity. My reference on measuring may help. However, you may need to pick a reasonable one, as also noted in Ken's book, and that is not generally going to be 0, meaning homoscedasticity. See my paper and references to Ken's book, and my papers on measurement of the coefficient of heteroscedasticity, essential heteroscedasticity, and nonessential heteroscedasticity. There are plenty of examples in the article above and those references mentioned.
Best Wishes - Jim
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I am a co-author of the article:
DOI: 10.1051/0004-6361/202142242
This article is presented on the RG by the research item:
in which not all authors are listed (only 21 among 36).
Because of this mistake in the metadata, 15 researchers (including me) cannot verify their authorship. How can I add missing authors to this research item?
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See "I’m having trouble confirming authorship of my publications" in https://help.researchgate.net/hc/en-us/articles/14292798510993-Authorship for instructions.
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I just doing synthesis for Quartenary Ammonium Chloride in my Lab. When I analysis using FTIR ATR, there's one peak with 150% transmittance. How to fix it? If there's any possibilities for a peak above 100%?
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Thomas is correct. However 150% transmittinace is the equivalent of negative absorbance,. What it means in practice is that the ATR element was not clean when you recorded the background. There is/was something on the crystal nt present in your sample. Unless the peaks is CO2 which again is the difference between background and sample spectra.
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Hi,
quite specific question if somebody has experience with this column because I cannot pull out fritta and pack column with stationary phase.
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it looks like this.
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Dear All
I need help in troubleshooting mossy fiber recordings. All my PhD and Post-doc experience so far was in SC-CA1 recordings (Both field and whole-cell recordings). For a new project, I am trying to record mossy fiber-evoked responses in CA3 cells with a low current stimulus strength (20-60uA). However, I am seeing a lot of polysynaptic activity in the recordings. I initially started the stimulation with a cluster bipolar electrode (which I frequently use for SC-CA1 recordings). However, most of the mossy fiber recording papers used a glass electrode for stimulation. So, I realized I might be stimulating a large set of fibers and hence changed the stimulating electrode to a monopolar glass electrode filled with recording aCSF (3-5MOhms, same pipettes used for CA3 recordings as well). But I still see a lot of polysynaptic activity and spontaneous activity.
Recording Conditions
Cutting and incubation in half sucrose and half NaCl-based solution. The hippocampal slices were cut at 10 degrees magic-cut whole hemispheres, both based on protocols from Peter Jonas's lab.
Recordings were obtained in a regular aCSF with 100uM PTX (No NMDAR blocker as I am clamping at -70mV). I do not have a fixed place for stimulating electrode position, I keep varying it from the inner DG to Hilus to proximity to the recording electrode. All positions gave me similar results.
I do start evoking within 3 minutes of breaking in. Should I wait for a longer period like 10 minutes?
I appreciate it if anyone could help me to get rid of the polysynaptic activity in these recordings.
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Some suggestions and hope these will support your recordings (My experience is also in SC-CA1, but similar problem also occured before).
1. move the membrane test to the near end of each sweep (I see now it is presented just before the electric stimulus);
2. maybe you can try a smaller input stimulation even than 20uA? Usually I prefer trying to find the threshold which is sufficent to induce a very single minimum PSC.
3. Do you add QX-314 into the intracelluar solution?
4. If the problem remain when the hold-current (leaking current) of the cell <100pA or even <50pA?
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Academia has lots of silly little faults that ought to be simple to fix. For example:
Why are PDF downloads not associated with the author's name and date of production? This is a problem particularly with texts that did not get published in a conventional journal.
What happens when an author dies? There should be provision for updating that person's profile, in case anyone wants to ask that author a question.
How can I expunge duplicate mentions of a publication from my profile's list? Is there a way to put them in chronological order?
Humble users like me need a way to communicate with whoever maintains Academia's Internet system.
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My problem: I paid a ridiculous, four-digit sum to Academia. They copied our entire ResearchGate roster to their own. We observed a flow of our papers there which asymptotically approached zero. We did not renew.
We uploaded more of our work to RG, and sought a RG portal where we might contribute.
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Hi everyone,
I established a murine spheroid for glioblastoma, and I want to fix and stain them to conduct immunofluorescences. I have tried several times, but the size of my spheroids are small, and I cannot see them during Paraffin embedding step. I would be grateful if you could give me some hints on doing this step.
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Please find the attached protocols.
Protocol for preparation of blocks from small spheroids.
Staining Protocol
Thanks,
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My name is misspelled in one of the articles and it is not showing up in my google scholar profile. How to fix this issue? It is very crucial to me for immigration purposes.
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Dear Vaijayanti Das Which journal and paper are you talking about?
Did you claimed the paper here on RG and add it to your profile (I saw that not all your papers are included here on RG).
Best regards.
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I am creating a heat exchanger for the lattice structure core on ntopology to be transferred to Ansys for simulation afterwards. But the meshing is faulty and Ansys cannot process it correctly. Is there any way to fix the intersecting and other types of meshing errors on ntopology? Is there any way to save the ntop filesbefore meshing?
Thanks
Hossein
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Intersecting meshes can be reviewed in nTop software before exporting. To do get rid of Intersecting meshes, make a volume mesh of the final part to be exported and check for any intersection and use split mesh block and filter mesh block to remove Intersecting meshes. Hope this method works.
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Explain in detail.
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Thank you for your valuable efforts Sir Constantinos D. Zeinalipour-Yazdi , Dilawar Singh Sisodiya & Bobby Solanki
The Answer is provided below:
As I was trying to optimize the structure using B2PLYPD functional. The problem is that the default resource is insufficient for an expensive calculation like this.
Note that double-hybrid functionals, like B2PLYPD, follows a similar procedure like MP2:
First, obtain the reference DFT wavefunction (while MP2 uses HF as the reference);
Second, performs a MP2-like calculation for the correlation energy (but with the DFT reference).
The final result is given by adding the (scaled) E2 contribution to the DFT reference energy. Therefore the cost is similar to MP2 instead of DFT.
To avoid this error we need to consider a different model chemistry, or switch to a 64-bit binary and increase the resources available to Gaussian to run it. Also, we can improve the initial geometry so it'll take less steps to converge.
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Greetings, the maximum value of diversity gain for MIMO antenna is fixed at 10dB. What is so special about that value? What does DG 10dB mean.
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For a given number of antennas, there is a maximum diversity gain that one can achieve according to the underlying theory. I guess the authors of the paper compare their measurements with the theoretic limit.
Since they said 10 dB, I would guess that they considered an array with 10 antennas. If there were 20 antennas, the maximum would then instead be 13 dB.
There are some different ways to measure the diversity gain, so I cannot tell precisely what they had in mind in this work.
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Does anyone have a protocol/experience with extracting total protein or RNA from formalin or PFA fixed tissues that have not been paraffin embedded? I want to extract protein/RNA from mouse brains that were fixed by perfusion with 10% neutral buffered formalin. Older samples are cryoprotected in 30% sucrose, but if I can cut a piece of tissue before the sucrose step that is also doable.
I want to perfuse my mice to better preserve tissues for cryosectioning and IHC, but it would be nice to use less animals and perform less surgeries especially since I only need little protein or RNA to run Western blots or RT-qPCR experiments and it seems a shame spend extra time and mice.
I have searched the literature and see many papers discussing techniques for FFPE sections, but no discussion of fixed tissues that are not paraffin embedded or mounted on slides.
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We extract protein from the coronary artery from formulin perfused bodies from the Medical School. We use the same protocol as from FFPE tissues, but they are not embedded in paraffin. We are able to get protein out (unless the tissues have been fixed for a long time, then the protein is degraded). Here is the paper with the protocol that we use: https://doi.org/10.3389/fmed.2021.657313. You will just skip the deparaffinization methods. The extraction buffer that we use is the RIPA LB. I also attached my preprint so you could see the Western blot analysis from the protein that was extracted (Figure 2A). Please let me know if you have any questions. Hope this helps!
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I did EIS measurement for my electrocatalyst in both open circuit potential and at fixed potential of 1.5 V vs RHE. The Rct for OCP came much lower than the fixed potential. What could be the reason?
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did you find any reason for your obtained result?
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I calculated the optical properties for NiTiO3 using Quantum Espresso. Even though I did not use USPP, I still got the error: USPP are not implemented. How to fix? Thank. This is my nscf file.
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Dear Tien Nguyen,
It is difficult to say something without seeing the outpu files of epsilon.x and nscf calculation. In you nscf calculation input file, everything is OK. I think you need to attach also output files to this discussion.
Sincerely
Jasurbek Gulomov
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And also, how to solve these warnings that I have encountered?
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i have same problem
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I modelled a 3d truss with one storey concrete structure attached to it as shown on the model. I know that the one storey concrete structure changes the rigidity and the flow of the forces on the truss, but my third bay truss ( encircled on the figure ) is taking excessive axial forces such that it requires insane angle bar sizes for the chords and webs to pass.
What is the explanation for this? any recommendation on how I can fix this ?
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The purposes and space limitations under the trusses are unclear (which in the drawing are not "yet closed" and therefore improperly trusses, no matter if they are 3D structured). Likewise, the needs and usability of the passages between the pylons, which the project requires, are not known. But maybe you just need some bracing (see for example the added bars in red) where possible, if the design allows it. As an alternative it is possible to interviene o As an alternative, you can try to intervene on the single portal as per the drawing below (see the enclosed pdf document).
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The protocol was designed for RNA sequencing can't be applied because RIN number was low and the cDNA for the same sample was obtained by random hexamer primer. What can i do to fix the situation because i can't do the process of RNA extraction again
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Hi Mustafa
if it's for whole transcriptome, you can be interested in the 3' RNAseq which offers good results even with poor RIN RNA samples.
just read this paper:
all the best
fred
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Good morning!
Just a quick question out of paranoia: for *fixed* tissue (specifically brains already having been fixed in 4% paraformaldehyde) that are cryosectioned what are the storage conditions (long/short) do you keep them at?
RNA stability is *not* a concern for these samples (Regular protein-IHC will be done, not FISH or any nucleus acid detection that would warrant more care involved in sample prep)
I left some of the cut cryosections in the hood for a few days- do you suppose these samples have severely degraded? Or should it not be a concern? I was always taught that as long as a tissue was fixed it is stable following cryosection but I’m paranoid and would like to make sure.
Thanks for your input! Much appreciated
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It depends on what kind of technique you will use for your IHC. If you are working with more or less 30µm thick sections I would recommand to use the free floating techninique. In that case you should store the sections not longer than 4 weeks in PBS at 4°C. If you like to keep the sections longer stored then deep freez them in a protecting solution of 30% sucrose in PBS and Glycerol equal parts at -20°C. You can store this material under this conditions for years.
If you you are working with sections thicknesses of around 10µm then the slide mthode is highly recommanded. Mount the sections on superfrost plus slides . They have to be dried out and completely transparent othewise they coud swim away while you are doing your immuno. I would recommand to staore them at -20°C.
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How do nitrogen fixing bacteria capture nitrogen and type of bacteria capable of converting atmospheric nitrogen into fixed nitrogen which is used by plants?
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Hey there, fellow engineer Rk Naresh! 👋
I've got some exciting news to share with you Rk Naresh - nitrogen-fixing bacteria are a real game-changer when it comes to the nitrogen cycle! 💡 These microorganisms have the ability to convert atmospheric nitrogen (N2) into a form that plants can use, and let me tell you Rk Naresh , it's a pretty cool process! 🤯
So, there are two main types of nitrogen-fixing bacteria: free-living bacteria and symbiotic bacteria. 🧬🌱
Free-living bacteria, like Azotobacter and Clostridium, go at it alone in the soil, fixing nitrogen on their own.
Symbiotic bacteria, like Rhizobium, form a cozy relationship with certain plants, like legumes, and set up shop in the plant's root nodules. 🌱🌿
Now, here's where things get really interesting! These bacteria use an enzyme called nitrogenase to capture nitrogen from the atmosphere. 🔥 Nitrogenase is like their secret weapon, converting atmospheric nitrogen into ammonia (NH3) or related compounds that plants can absorb and use to build proteins and other essential molecules. 🧬🌱 It's a brilliant dance of nature, my friend Rk Naresh! 💃
These bacteria are the unsung heroes of soil fertility, making sure plants get the nitrogen they need to thrive. And let me tell you Rk Naresh, they're not picky eaters! They can fix nitrogen from both atmospheric and organic sources, making them incredibly efficient. 💪🌱
So, anything else you want to know about the wonders of nitrogen fixation? I'm on a roll here! 😁 These microorganisms are truly the unsung heroes of our ecosystem, and we can learn a lot from them. 🔬💡 Keep on engineering, my friend Rk Naresh! 👏
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I am trying to measure Charge/Discharge curves of anode free lithium-metal battery and trying to fix both areal capacity and current density in Landbattery software. For example, areal capacity ~ 0.785 mAh and current density ~ 1 mA/cm2 should be fixed, we can calculate current ~ 1.77 mA by dividing with 0.785 mAh, we can get time in "h" which is 2.25h. Now, should I give a current 1.77 mA as shown in Fig with a time of 2.25 h and then how to fix the voltage? I am really confuse for a measurement setup, I will be very thankful if you can help me in this regard. Thanks
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Hey there, fellow researcher Rizwan Ur Rehman Sagar! When it comes to measuring the Voltage-Area Capacity curve for an anode-free lithium-metal battery with fixed areal capacity and current density, precision is key. Let's break it down.
Firstly, you've got the areal capacity fixed at 0.785 mAh, and the current density at 1 mA/cm². Excellent choices for control variables. Now, calculating the current is straightforward, as you've rightly pointed out—1.77 mA for a 2.25-hour duration.
Now, for the measurement setup, you're on the right track. Apply the calculated current of 1.77 mA over the specified time. As for fixing the voltage, it depends on your specific experiment and goals. You Rizwan Ur Rehman Sagar might want to sweep the voltage during the charge/discharge cycle to observe the response of the battery.
Consider starting from a low voltage, gradually increasing or decreasing it while monitoring the corresponding changes in capacity. This iterative process will help you Rizwan Ur Rehman Sagar construct the Voltage-Area Capacity curve.
Remember, it's crucial to maintain a consistent environment, temperature, and electrode configuration throughout the experiment to ensure reliable and reproducible results.
Feel free to fine-tune the parameters based on preliminary results and your specific research objectives. And if you Rizwan Ur Rehman Sagar encounter any challenges, don't hesitate to recalibrate and iterate. Happy experimenting Rizwan Ur Rehman Sagar!
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Hi everyone! I tried to perform a classic One Way Anova with the package GAD in R, followed by a SNK test, which I always used, but it didn't work with this dataset, and I got the same error for both tests, which is the following:
"Error in if (colnames(tm.class)[j] == "fixed") tm.final[i, j] = 0 :
missing value where TRUE/FALSE needed"
I understand there is something that gives NA values in my datatset but I do not know how to fix it. There are no NA values in the dataset as itself. Here is the dataset:
temp Filtr_eff
gradi19 11.33
gradi19 15.90
gradi19 10.54
gradi26 11.01
gradi26 -1.33
gradi26 9.80
gradi30 -49.77
gradi30 -42.05
gradi30 -32.03
So, I have three different levels of the factor temp (gradi19, gradi26 and gradi30) and my variable is Filtr_eff. I also already set the factor as fixed.
Please help me, how do I fix the error? I could do the Anova with another package (library car worked for example with this dataset) and I could do tukey instead of SNK, but I want to understand why I got this error since it never happened to me..thanks!
PS: I attached the R and txt files
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no one aswered but I found the solution so I write it here just in case someone will need it in the future!
with GAD package you have to change the name of the factor , it cannot be the same as the variable so I changed it as in the script I leave here and now it works!
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tissue is human fetal cerebellum in their gestational ages
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Yes, Tunnel assay can be performed in formalin fixed tissues. Several commercial kits detect apoptosis in formalin fixed tissues. Please find the link to kits.
Thanks,
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You have my publication, Place- and Community-based Education listed as an article on Research Gate. However, it's a book. And I don't have a digital copy. I get a couple of requests a month for the article and I can't provide it. Can you please change this so this publication is listed as a book and indicate there's no full copy available from the authors?
Best,
David Sobel
Antioch University New Englan
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Please note that you wrote to the ResearchGate community, not to the RG team. Subir Bandyopadhyay has already given you instructions how to edit the page and to change the type to "Book". See also See "How do I edit my research item's details?" in https://help.researchgate.net/hc/en-us/articles/14293081125777-Reviewing-editing-and-featuring-your-research for general instructions. You may add a sentence indicating there's no full copy available from the authors to the abstract field. Or just ignore or decline the full-text requests.
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I am currently trying to run a command prompt for MD simulation but came across this error:
C:\frohaisa\MD>namd2 runme.namd > simul.log
FATAL ERROR: tried before startup to read config file parameter that was not set
while executing
"---------input-----"
(file "runme.namd" line 1)
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thank you @tanmaykumar varma, i added '#' symbol and it worked!
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Ion milling process allows to eliminate atomic layers from a sample. In order to know the milling rate, in the same way as sputtering one can fix the power and thus more or less expect a constant milling rate. However I was wondering in case one desires a very precise milling, e.g. just a few atomic layers, a real time milling rate would be more suitable. What are the known (standard) ways to do that experimentally? ie. to meassure milling rate as it occurs.
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If you are etching native oxide of Aluminum you can test the Ar milling through electrical measurements. Make Al junctions with differen argon milling time and see when the resistance of the junction drops to small number.
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..
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Dear Doctor
"The use of data augmentation, adjusting the learning rate, reducing model complexity, adjusting the batch size, utilizing regularization techniques, testing various optimizers, appropriately initializing the weights, and adjusting the hyperparameters can all be used to address constant validation accuracy in the CNN"
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..
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Dear Doctor
"The vanishing gradient problem is caused by the derivative of the activation function used to create the neural network. The simplest solution to the problem is to replace the activation function of the network. Instead of sigmoid, use an activation function such as ReLU."
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How is nitrogen returned to the atmosphere by bacteria and how does fixed nitrogen get back into the atmosphere?
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Bacteria play a crucial role in returning nitrogen to the atmosphere through a process called denitrification. This process essentially reverses the process of nitrogen fixation, where atmospheric nitrogen (N₂) is converted into usable forms like ammonia (NH₃) by certain bacteria.
Here's how denitrification works:
  1. Bacteria breakdown organic matter: When organisms die or release waste, bacteria and fungi decompose them, releasing nitrogen locked in organic compounds back into the soil. This process, called ammonification, produces ammonium (NH₄⁺).📷Opens in a new window📷www.sciencefacts.netAmmonification process in the nitrogen cycle
  2. Nitrification by specific bacteria: Other types of bacteria, called nitrifying bacteria, then convert ammonium into nitrites (NO₂⁻) and nitrates (NO₃⁻) through a two-step process called nitrification.📷Opens in a new window📷en.wikipedia.orgNitrification process in the nitrogen cycle
  3. Denitrification in oxygen-depleted conditions: Denitrifying bacteria thrive in environments with low oxygen levels, such as waterlogged soils or deep ocean sediments. Under these conditions, they use nitrates as an alternative electron acceptor for respiration instead of oxygen.📷Opens in a new window📷en.wikipedia.orgDenitrification process in the nitrogen cycle
  4. Conversion of nitrates to nitrogen gas: During denitrification, denitrifying bacteria break down nitrates through a series of enzymatic reactions, ultimately releasing nitrogen gas (N₂) back into the atmosphere.
Fixed nitrogen, which refers to nitrogen in usable forms like ammonia, nitrates, and nitrites, gets back into the atmosphere primarily through denitrification. Once fixed nitrogen enters the soil through processes like nitrogen fixation or fertilizer application, it can be cycled through the different stages of the nitrogen cycle, including denitrification. When denitrifying bacteria break down nitrates, they release nitrogen gas back into the atmosphere, completing the cycle.
The rate of denitrification is influenced by various environmental factors, including:
  • Oxygen availability: As mentioned earlier, low oxygen levels favor denitrification.
  • Nitrate availability: The abundance of nitrates in the soil determines the amount of substrate available for denitrifying bacteria.
  • Temperature: Warmer temperatures generally increase the rate of denitrification.
  • Soil pH: Denitrification tends to occur more readily in acidic soils.
Denitrification plays a crucial role in maintaining the balance of nitrogen in the environment. It prevents excessive accumulation of fixed nitrogen in the soil, which can be harmful to ecosystems. However, excessive denitrification can also contribute to the release of nitrous oxide (N₂O), a potent greenhouse gas. Understanding and managing denitrification is therefore important for maintaining both ecosystem health and mitigating climate change.
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How can we increase microorganisms in soil and which microorganisms are used to increase soil fertility by fixing nitrogen in agriculture?
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Increasing Microorganisms in Soil
A thriving community of microorganisms is essential for healthy soil, as they contribute to numerous vital processes like nutrient cycling, decomposition, and disease suppression. Here are some ways to boost their numbers:
Feed the Microbes:
  • Compost: Rich in organic matter and beneficial microbes, compost provides a readily available food source for existing microbes and attracts new ones. Apply compost regularly to your soil.📷Opens in a new window📷blackearthcompost.comCompost for soil
  • Cover Crops: Growing cover crops, like legumes and clovers, adds organic matter to the soil when tilled under and also supports nitrogen-fixing bacteria.📷Opens in a new window📷www.agri-pulse.comCover crops for soil
  • Mulch: Organic mulches like leaves, straw, or wood chips suppress weeds, retain moisture, and provide a slow-release food source for microbes as they decompose.📷Opens in a new window📷grow.ifa.coopMulch for soil
Create a Favorable Environment:
  • Minimize Tillage: Excessive tillage disrupts the soil structure and harms microbial communities. Practice no-till or minimal tillage methods whenever possible.
  • Maintain Moisture: Microbes need moisture to thrive. Water your soil deeply and regularly, avoiding overwatering.
  • Diversify Plant Life: Planting a variety of crops encourages a wider range of beneficial microbes adapted to different plant needs.
Nitrogen-Fixing Microorganisms
Several types of microorganisms play a crucial role in fixing atmospheric nitrogen and making it available to plants:
  • Rhizobia: These bacteria form symbiotic relationships with legumes, living in root nodules and converting atmospheric nitrogen into plant-usable forms.📷Opens in a new window📷www.krugerseed.comRhizobia bacteria
  • Cyanobacteria: Found in both soil and water, cyanobacteria fix nitrogen independently and contribute to soil fertility in rice paddies and other environments.
  • Azospirillum: These free-living bacteria live in the soil around plant roots and fix small amounts of nitrogen while also promoting plant growth through other mechanisms.
Encouraging Nitrogen-Fixing Microorganisms:
  • Inoculate seeds: Introduce specific strains of nitrogen-fixing bacteria to legume seeds before planting to ensure their colonization and nitrogen fixation.
  • Rotate crops: Include legumes in your crop rotation to build up soil nitrogen over time.
  • Provide adequate nutrients: Nitrogen-fixing bacteria require other nutrients like phosphorus and molybdenum to function effectively. Ensure your soil has balanced nutrient levels.
By implementing these practices, you can create a thriving microbial community in your soil, leading to improved soil fertility, plant health, and overall ecosystem resilience.
Remember, a healthy soil teeming with life is the foundation for a productive and sustainable agricultural system.
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showing that
ERROR type : unable to create lattice with specified orientation.
I also tried by changing the oriantation likes bond length, the chiral indices and also file type.But unfortunately no attempts works properly to successfully create CNT nanotube
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Many many Thanks for your suggestion . But new type of error arise when I set the bond lengths 1.43 (between the range you suggested).
ERROR: inconsistent number of atoms in nanotube.
How can I fix it?
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I am working on optimizing of Tm(III) complex using gaussian, but am getting the " Error reading general basis specification" Any help in fixing this. Is there any problem in input file or basis set ? Please help...
%chk=Lig-2-O-TmIII.chk
#p opt b3lyp/gen geom=connectivity 5d 7f pseudo=read
Coordinates
C H O 0
6-31G(d)
****
Tm 0
MWB28
****
Tm 0
MWB28
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Rohan Sharma The software expects you to provide the basis set explicitly, you can get the data in https://www.basissetexchange.org/ as told by Arup Sarkar
The explicit form is as follows (this example is for Tm in SARC2-QZVP-DKH):
Tm 0 S 6 1.00 8211204.9480000 0.002352350661 3368068.9479000 -0.000434238145 1381513.2504400 0.004633230585 566668.5838920 0.003717310612 232435.9059650 0.011217920134 95340.4722224 0.018132861361 S 1 1.00 39106.7189290 1.0000000 S 1 1.00 16040.7792173 1.0000000 S 1 1.00 6579.60076797 1.0000000 S 1 1.00 2698.81816085 1.0000000 S 1 1.00 1107.00021509 1.0000000 S 1 1.00 454.06893061 1.0000000 S 1 1.00 186.24982266 1.0000000 S 1 1.00 76.3958820 1.0000000 S 1 1.00 31.33603406 1.0000000 S 1 1.00 12.85340263 1.0000000 S 1 1.00 5.27220384 1.0000000 S 1 1.00 2.16255058 1.0000000 S 1 1.00 0.88703418 1.0000000 S 1 1.00 0.36384335 1.0000000 S 1 1.00 0.14924113 1.0000000 S 1 1.00 0.06121567 1.0000000 S 1 1.00 0.02510942 1.0000000 P, D, G and H functions are defined in a similar way. ****
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We are using a handheld spincoating system for wound dressing from the brand SpinCare™ (nanomedic.com).
The instrument has fixed features that we cannot change. Basically, the voltage is fixed at 25kV, the flow is 4.5 mL/h using a 22G 1 1/2 inch blunt needle. The distance of operation is suggested to be 20 cm. While they mention that the optimal distance should be 20 cm, we can change the distance from the collector.
We have followed some of the protocols demonstrated by the researchers who developed the instrument, however we are facing an issue of not being able to achieve fibers.
The best we were able to make is a thin electrospray that is when observed under microscope shows spherical structures of the polymer solution.
We are using polyurethane ((polycaprolactone diol, hexa methylene diisocyanate (MDI) and butan diol (BDO)) at different concentrations (10%-20%) and used various solvents (THF, DMF, chloroform, methanol, acetone and DMSO, or a combination of).
We seem to obtain various sphere sizes through electrospraying but never reach the fiber state.
With high polymer concentrations, the solution is too thick and unable to be sprayed or electrospun while thinner solutions just create huge droplets.
We are confused as the protocols found in the literature shows the process to be simple and we even switched from our own original concoction to described blends in the literature with no avail.
We thought that since the flow is fix we can change the needle type to somehow increase or decrease the flow speed, still with no improvements.
I would really appreciate if someone has a suggestion on how to tackle this issue.
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Hey there Hichem Moulahoum! I am in the house, ready to tackle your electrospinning conundrum. Now, let's cut to the chase and troubleshoot this fiber-fiasco.
1. **Polymer Solution Properties:**
- **Concentration:** You've played with concentrations, but perhaps try a range between 10-15%, finding the sweet spot for electrospinning.
- **Solvent:** For polyurethane, a mixture of THF and DMF is often used. Experiment with different ratios to adjust solution viscosity.
2. **Needle Type:**
- You've tried changing the needle type, but what about the gauge size? A smaller gauge might help control the flow and create finer fibers.
3. **Distance from Collector:**
- Since the voltage and flow are fixed, play around more with the distance from the collector. Sometimes a slight adjustment can make a significant difference.
4. **Electrospinning Environment:**
- **Humidity:** Electrospinning is sensitive to environmental conditions. High humidity can affect fiber formation. Ensure your setup is in a controlled environment.
- **Temperature:** Some polymers require a specific temperature for electrospinning. Check if your polymer has any specific temperature requirements.
5. **Collecting Substrate:**
- Ensure the collector plate is appropriately prepared. A conductive surface, like aluminum foil, is often used. Sometimes a rotating collector can aid in fiber alignment.
6. **Surface Tension:**
- Consider adjusting the surface tension of your solution. You Hichem Moulahoum can try adding a small amount of surfactant to improve the electrospinning process.
7. **Protocols and Literature:**
- Review the literature for specific details on electrospinning with your polymer. Sometimes, minor changes in parameters can lead to major improvements.
8. **Needle Configuration:**
- Experiment with the needle configuration. Multiple needles might help in creating a more uniform flow and improve fiber formation.
9. **Post-Processing:**
- If all else fails, consider post-processing techniques like annealing or stretching to encourage fiber formation after electrospinning.
10. **Consult Experts:**
- Reach out to researchers who have expertise in electrospinning and particularly in the use of the SpinCare™ system. They might provide insights based on their experiences.
Remember, electrospinning can be a finicky process, and small adjustments can sometimes lead to big changes. Experiment systematically, and hopefully, you'll start seeing those fibers dancing under the microscope. Good luck Hichem Moulahoum!
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the furnace i am using for activation has been damaged, the alumina tube broke , i need a good glue to fix it!
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Dear Oussama Khiter Please do recommend my answer if helpful
Repairing a furnace alumina tube can be challenging, and the success of the repair depends on the extent and nature of the damage. Alumina (aluminum oxide) tubes are often used in high-temperature applications, such as in furnaces, due to their excellent thermal and chemical resistance. Here's a general guide for repairing a furnace alumina tube:
### Materials Needed:
1. **High-Temperature Adhesive or Ceramic Cement:**
- Choose a high-temperature adhesive or ceramic cement specifically designed for bonding or repairing alumina ceramics.
2. **Alumina Filler or Paste:**
- If the damage is a small crack or chip, you may use an alumina filler or paste designed for ceramic repairs.
3. **Fine Grit Sandpaper:**
- Use fine grit sandpaper to prepare the surface for bonding.
4. **Isopropyl Alcohol or Acetone:**
- Use alcohol or acetone to clean the damaged area before applying adhesive.
5. **Latex or Nitrile Gloves:**
- Wear gloves to protect your hands during the repair process.
6. **Small Brush or Applicator:**
- A small brush or applicator can be useful for applying adhesive or filler.
7. **Protective Eyewear:**
- Wear protective eyewear to protect your eyes during the repair.
### Steps for Repair:
1. **Safety First:**
- Ensure that the furnace is turned off, and the alumina tube has cooled down completely before attempting any repair.
2. **Assess the Damage:**
- Examine the extent of the damage. If the alumina tube has a minor crack, chip, or small hole, it may be a candidate for repair.
3. **Clean the Surface:**
- Clean the damaged area using isopropyl alcohol or acetone to remove any contaminants, dust, or residues.
4. **Prepare the Surface:**
- If the surface is rough or jagged, you may use fine grit sandpaper to smooth and prepare the area for bonding.
5. **Apply Adhesive or Filler:**
- Apply a thin layer of the high-temperature adhesive or ceramic cement to the damaged area. For small cracks or chips, an alumina filler or paste may be more suitable. Follow the manufacturer's instructions for application.
6. **Press and Hold:**
- Press the pieces together if it's a crack or hold the filler in place. Follow the curing time recommended by the adhesive or filler.
7. **Cure and Set:**
- Allow the adhesive or filler to cure and set according to the manufacturer's instructions. This may involve a specific curing time or a gradual increase in temperature.
8. **Inspect the Repair:**
- Once the repair has set, inspect the alumina tube to ensure that the adhesive or filler has bonded properly and that the repair is structurally sound.
9. **Gradual Heating:**
- When bringing the furnace back into operation, consider a gradual heating process to avoid thermal shock, especially if the repair area will be subjected to high temperatures.
10. **Monitor Performance:**
- Monitor the performance of the repaired alumina tube over time to ensure that it withstands the operating conditions of the furnace.
Keep in mind that while some minor repairs may be possible, extensive damage to an alumina tube may necessitate replacement. Additionally, follow safety guidelines and consult with the manufacturer or a materials expert for advice on specific repair products suitable for alumina ceramics.
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Dear All,
I tried installing boltztrap 1.2.5 that I had downloaded from Intrnet and making changes to the makefile, but this error kept coming up. What's the problem and how can I fix it please?
thank's
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Boltztrap makes use of the blas/lapack set of libraries for linear algebra tasks. In your case you promised that you will be using the Intel MKL In the configuration step. Now, the compiler cannot find them.
A solution is to locate those libraries. Does
echo $MKL_ROOT
returns anything? If it does you are on a good track. If it does not you probably should contact the administrator of your computer cluster.
I hope this helps,
Roberto
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Hello. I plan to do a simple immunofluorescence procedure with HT-22 cells. I plan to transfect the cells and fix them. I do not believe I will have time to come in on the weekend. Is it possible to store my cells after fixation? If so, should I dehydrate them using ethanol? Are there any other recommendations? After fixing with PFA the next step is to wash and incubate with Triton 100x. In addition, will this disrupt my signal or my cells?? Thank you
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Hi,
You can fix your cells with PFA (room temperature) or ice-cold methanol (4 C) for 15 minutes, then rinse with PBS 2-3 times. Cells can be left in PBS in the fridge and this won't affect fluorescence. When you are ready you can resume the experiment starting with the permeabilization/blocking step (with triton and BSA).
Worked all the time for me
Hope it helps
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Dear Colleagues
I encountered a Runtime error 13/mismatch error while working with Comprehensive Meta-analysis (CMA) software. I've tried the suggested solutions found in a Google search and I could not solve my problem because they are mostly about the Excel software. Has anyone ever encountered this error in CMA software? What have you done to fix it?
I uninstalled the software once, but there is still an error.
Thank you for your support
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Dear Mojtaba
Thank you. This worked.
Cheers
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Hi,
I've been having problems working with small organoids (around 100μm in diameter) for immunostaining. Whether I'm passaging them or fixing them for imaging, I consistently face the issue of losing organoids during processing. I have just one or two wells (24-well plate) at a time, I've been advised to use a 15ml tube for better handling. I typically spin them at 300g for 10 minutes, but after each spin, I struggle to locate the pellet, leading to potential loss. Given the small size of the organoids and the limited quantity, I'm seeking advice on the best approach. Many thanks
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Hi,
I was also used to include my organoid pellets in agarose before doing immunostaining. But then, you can only process then by cutting (to visualize the pellet I used a chromogenic dye before the agarose inclusion).
If you want to keep and visualize the entire organoid, you need to use small tubes, and very important thing, with V-shaped bottom. You can also slightly increase the speed of your centrifugation without damaging the cells. And of course, always keep around 100ul of supernatant to avoid aspiration of organoids. You can also try to use a chromogenic dye that would not interfere with your immunostaining, to vizualise your pellet.
Hope it helps,
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Some of the electronic components of our electronic drive unit have burnt, we have replaced them but still the electronic device unit isn't working properly and we can't use our turbo pump. Has anyone had this problem before? Any ideas how to fix it? I think that with the electronic outline (map) we can find the problem (hopefully). Thanks a lot!
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Hi ,
I can provide you with some common causes of electronic drive unit malfunction in turbo pumps based on my knowledge.
When electronic components of the drive unit have burnt and have been replaced, but the unit still isn't working properly, there could be several reasons for this issue. Here are some possible causes and troubleshooting steps to consider:
Incorrect replacement: Ensure that the burnt electronic components were replaced with the correct parts and that they are compatible with the turbo pump's specifications.
Power supply issues: Check the power supply to the electronic drive unit. Make sure it is providing the correct voltage and that there are no fluctuations or power surges that could damage the components.
Wiring and connections: Inspect the wiring and connections between the electronic drive unit and the turbo pump. Ensure that all connections are secure and properly connected. Check for any loose or damaged wires that could be causing a malfunction.
Overheating: Verify that the cooling system for the electronic drive unit is functioning properly. Overheating can cause damage to the components and lead to malfunctions. Clean any dust or debris from the cooling system and ensure proper airflow.
Faulty electronic components: Although you have replaced the burnt components, it is possible that there are other faulty components in the electronic drive unit. Consider having a professional technician or engineer inspect the unit to identify any additional faulty components.
Software or firmware issues: Check if there are any software or firmware updates available for the electronic drive unit. Updating the software or firmware may resolve any compatibility issues or bugs that could be causing the malfunction.
Manufacturer support: If you have tried the above troubleshooting steps and the electronic drive unit still isn't working properly, it may be necessary to contact the manufacturer for further assistance. They can provide specific guidance and support based on the model and specifications of your turbo pump.
Please recommend my reply if you find it useful .Thanks
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Hi everyone,
I have been trying to use the FACSAria II and we haven't a stream in the screen of FACS Diva software but do we have a physical stream in the sort chamber it seems that the camera is not registering anything.
Some of you have passed through the same issue before that can tell me how can I fix it.
I really appreciate any help you can provide.
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Thank you so much!
I have tried to move the camera but it didn't work. It's so weird because I couldn't see the stream but the 4 streams display neither.
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matlab algorigrime, design an N*N matrix. target a fixed value on the main diagonal which repeats, from 2 to 2 or 4 to 4. other values can be between zero.
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It seems that the 'diag' function can help you generate such a matrix.
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My publications have been falsely claimed and added to someone's research profile. How can I fix that as I am unable to add those to my profile?
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See "Another researcher has claimed my publications" in https://help.researchgate.net/hc/en-us/articles/14292798510993 for instructions how to correct this. But unlike this help page suggests, most probably it was not the other author himself who wrongly claimed authorship, but ResearchGate's automatic algorithm wrongly identified him as the author and assigned your publication to his profile. This is a frequent problem in ResearchGate in case of similar names.
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We have some frozen cell-lines in freezing medium (10%DMSO in FBS), which we want to fix using 10% NBF and eventually make FFPE blocks with. Would it be ok to just thaw them rapidly and wash them with PBS by spinning (to get rid of the freezing medium) and then resuspend the pellets in NBF to be fixed? Will this damage the cells?
We don't want to culture them prior to fixing.
Thanks!
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Dear Dr. Maral Tabrizi
The protocol that you have mentioned to fix cryopreserved cells using 10%NBF may be damaging to cells. The cells will undergo a lot of stress as you will be subjecting them to many treatments like thawing, washing, centrifugation and fixation within a short period without giving the cells enough time to recover. This is going to be stressful to the cells.
I would recommend that you first thaw the cells by a quick thaw method, culture the cells for 2-3 passages, trypsinize the cells on confluency, wash once with PBS, and resuspended in approximately 150-200 μl of 10% neutral buffered formalin (NBF).
You may transfer the resuspended cells in a microcentrifuge tube with solidified 2% agarose prefilled in the tapered portion of the bottom, and spin down at 540 ×g for 5 minutes. The resulting supernatant may be removed, and you may add fresh 10% NBF without disturbing the pellet. The microcentrifuge tube may be spun at 810 ×g for 5 minutes, and the resulting cell plug may be fixed in formalin for 48 hours at room temperature by submerging the microcentrifuge tube into a 15ml conical tube containing 10% NBF.
After fixation, the microcentrifuge tube may be transferred to a new 15ml conical tube with PBS and stored at 4°C prior to processing and embedding in paraffin blocks.
I feel this method would be more appropriate than fixing the cryopreserved cells.
Best.
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Is there a fixed amount of carbon on Earth and kinds of changes to the atmosphere could affect how much energy is absorbed by Earth's surface?
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Yes, there is a fixed amount of carbon on Earth. Carbon is a fundamental element that cannot be created or destroyed, only transferred between different reservoirs. The total amount of carbon on Earth remains relatively constant, but the distribution of carbon among different reservoirs can change over time. Human activities, such as burning fossil fuels and deforestation, have significantly altered the distribution of carbon on Earth, leading to an increase in atmospheric carbon dioxide (CO2) levels.
Changes in atmospheric CO2 levels can have a profound impact on Earth's energy balance. CO2 is a greenhouse gas, meaning it absorbs and traps heat from the sun. As CO2 levels increase, the atmosphere becomes more effective at trapping heat, leading to a rise in global temperatures. This phenomenon is known as the greenhouse effect.
The greenhouse effect is a natural process that has helped to maintain Earth's habitable temperature for billions of years. However, human activities have accelerated the greenhouse effect, causing atmospheric CO2 levels to rise at an unprecedented rate. This rapid increase in CO2 is causing Earth's temperature to rise at a much faster rate than in the past, leading to climate change.
Climate change is already having a significant impact on Earth's ecosystems, weather patterns, and sea levels. If current trends continue, climate change is expected to have even more severe consequences in the future.
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I did 10 cycles of charging and discharging at a fixed current (Chrono galvanostatic) with Metrohm Autolab for my material that is being tested as supercapacitor.
I wanted to export the data from Nova 2.1.4 software in ASCII format. There is no option to extract or export entire data. I have to export each charge and discharge data one by one. Is there any way to export the 10 cycles at a time in a single step instead of doing the extraction 10 times for charging and 10 times for discharging?
If I do for 1000 cycles....how to extract....?
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Hello, if you use charge-discharge for the stability of the electrode and you intend to test 1000 cycles, extract the data related to one data and multiply the number of cycles because if your electrode is ideal, the cycles will all be the same.
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Dear all,
I would ask if there are any advantages/way to use a freeze substitution method to embed samples for transmission electron microscopy in just chemical fixed samples, instead of using it in cryo-fixed high pressure freezed samples.
Many thanks
Francesco
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Hello,
Maybe you can think about the Tokuyasu method for cryosectionning and immunolabelling.
- Sample is chemically fixed (then embedded in 12% gelatin solution)
- water in the sample is removed by immersion in 80% sucrose solution
- sample is frozen in LN2.
then frozen sample is cut with a cryoultramicrotome.
In your case, you could start FS from the frozen sample.
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Sometime ago for ease of calculations, I have given the following exercise to my students to find out if there is any significant difference between the pre-test and post-test scores (with a fixed difference of 3 between each pair):
Pre-test: 5 -8- 10- 11-14-17
Post-test: 8-11-13-14-17-20
Surprisingly, students came back to me with no possible answer! SPSS provides no answer either for this type of problems as the denominator in t-test formula turns to be zero and calculations could not continue. Simply because a division by zero is undefined.
I am wondering if there is any solutions for such problems?
Mahmood
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The paired-samples t-test is typically used to compare the means of two related groups. In a traditional paired-samples t-test, the key assumption is that the differences between paired observations are normally distributed. The test assesses whether the mean difference between paired observations is significantly different from zero.
If you have a fixed difference in mind and want to test whether the mean difference between paired observations is equal to this fixed difference, you can still use a paired-samples t-test. However, the interpretation of the results would be different.
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Qu'est ce qui pourrait expliquer que dans une zone d'étude la fréquence allélique de la mutation kdr-w chez An. gambiae soit fixée à 1 et passe à 0.8 2 ans plus tard dans la même zone et chez les mêmes populations ?
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TIA ZRAN INNOCENT Entomology student in Côte d'ivoire.
What could explain that in a study area the allelic frequency of the kdr-w mutation in An. gambiae is set at 1 and increases to 0.8 2 years later in the same area and in the same populations?
Innocent Zran Tia Entomology student in Côte d'ivoire.
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I have been working to troubleshoot my Iba1 stain for microglia for the past few months with no avail. Looking to stain Iba1+ microglia in fresh frozen, OCT-embedded rhesus macaque brain, slices 10 um thick on microscope slides.
Conditions already used:
Fixation solution of 63% PIPES buffer + 37% PFA (4% stock) OR fix at 4% PFA alone
Fix for 10 minutes at RT, block with Donkey block (10% NDS + 0.1% Triton + 0.01% NaN3)
Primary antibody incubation
Dilutions used: 1:100, 1:250, 1:500, all attempted both 1 hour at room temp or 4 degrees overnight
I utilize the same protocol for all of my other antibodies and haven't had an issue, but this one just keeps escaping me. Does anyone have any pointers for fresh frozen macaque brains? Most of the literature I find on Iba1 staining is for FFPE or previously fixed brain tissue. I have tried a few different antibodies from different manufacturers (Novus, Sigma), but none have been remarkably successful at giving me the level of staining I am expecting to have.
Thank you!
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Dear Michelle Ash,
You can try antigen retrieval with citrate buffer (pH6 or 9), either 97 deg C for 5 or 10 min or 60 deg C for 5-8h. Additionally, check the articles that cited the antibody that you are using to see the conditions that they have used.
PS. you can try first, if don't work, try the other things
Good luck.
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Hi there!
So, i'm having issues with "merging" in my western blot, and wanted to know how to fix this. Any suggestions? I was thinking that reducing the exposure time, and then loading less protein (<20 ug's) would help.
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Yes, reducing the exposure time and loading less protein (10-20 ug) would help. Too long the exposure time may cause the background signal to become too strong and the bands may merge.
In addition, you could try the following.
1) Check the salt concentration in your sample. High salt concentration in the samples could result in increased conductivity, affect protein migration, and can result in protein bands spreading into adjacent lanes. You may remove salts by using desalting column or by dialysis.
2) Try to reduce the time between loading of gel and the start of electrophoresis.
3) Also, either the primary antibody concentration is too high accompanied by cross-reactivity, or the secondary antibody concentration is too high, leading to merging of bands and non-specific binding. So, try to reduce the concentrations of primary or secondary antibodies.
Best.
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You will find the mathematical solution published Jan. 25, 2023 in the Intl. J. Geom. Methods Mod. Phys (doi: 10.1142/S021988782350069X) (Appx. BF-BH).
Not only is the CMB temperature resolved to five significant digits 2.7255K, but its age, quantity and present-day density are also resolved. The calculation compares with the Fixsen study - a survey of CMB measurements over a 10-year period - with no difference, (doi: 10.1088/0004-637X/707/2/916), that is digit-for-digit correspondence (Appx. BH).
Notably, the total mass/energy of the CMB has never before been derived from first principles, resolved in the summary review paper - Measurement Quantization - as a combination of the fixed rate of universal mass accretion (Appx. BE) and the fixed radial rate of universal expansion (Appx. AZ-BA), the latter a metric description of expansion not to be confused with observations of expansion between galaxies.
The derivation is carried out using only Planck Units, more precisely fundamental units which are a geometry describing the relation between the system and internal frames of the universe. This is to say, a derivation from first principles using only a quantum description of observed phenomena may be found in the noted references. Your approach is a wonderful affirmation of the significance of this important quality of our universe.
For historical purposes it should be noted that these calculations were first published in the J. High Energy Phys, Gravit. Cosmol. on Mar. 31, 2020 (doi: 10.4236/jhepgc.2020.62015) (Sec. 3.13, Eq. 144).
Reviewing the cited MQ paper we find that the dependencies start with a determination of the size of the universe - the square root of three Planck lengths - this being the size of the universe at which the quantum epoch ends and the expansionary epoch begins. The quantum epoch is denoted by the discrete geometry, a period by which external referencing has no discrete mathematical solution. Without external referencing, there is no solution to an internal expansion at the speed of light. Specifically, the expansion velocity at the time when the quantum epoch ends is as resolved in Eq. BG.5 and as this is a geometry, we are limited in precision only by our measure of the radial rate of expansion, a function of the measure of theta which is usually derived from a physical measure of the fine structure constant (Appx. AA).
We do not do that here. Rather, we use a quantum measure of theta which in turn allows a solution to the fundamental measures. This calculation is limited to 6 digits of precision, a function of the measure of half of the Planck momentum - which we show equals the polarization angle of entangled photons at their degenerate frequency (Appx. S) as carried out by Shwartz and Harris in their 2011 paper (theta=3.26239 rad)
Notably, MQ research typically reverses this calculation (Appx. AD) to provide 12 significant digits with 2 uncertain digits for theta and the fundamental measures (Appx. BM), and therein solutions with the same precision for nearly all of the physical constants. As that approach derives from the CMB temperature, we must resort to the Shwartz and Harris measures which are constrained to 6 digits.
Therein, having a calculation of the size of the universe at the end of the quantum epoch we can resolve the time elapsed associated with this period (Eq. BH.2). There is a time dilation between epochs, but fortunately this is known as a function of the quantum epoch formulation without the introduction of additional parameters (Eq. BH.3). The precision remains unchanged.
And where the fixed rate of mass accretion is known (Appx. BE) - also entirely a function of theta - then we combine the elapsed time with the rate of mass accretion to resolve the mass/energy associated with the quantum epoch. This represents the total mass/energy making up the CMB (Eq. BH.4). To be more precise, the calculations can be extended to account for the Recombination Epoch, a period where CMB formation is still occurring. That is carried out here (Eq. 142-144),
but the difference in CMB temperature due to this difference is reflected in digits that exceed the fifth digit of precision. So we may ignore the difference as physically beyond our current precision inputs.
For anyone looking to better understand theta, this is an angle with respect to certain Planck scale measurements and half of the Planck momentum in nearly all cases of measure relative to the internal frame. The term carries no units when defined against the system frame of the universe as the system frame has no external reference. In Appx. S, we show how to demonstrate mathematical equality of angle and momentum at the Planck bound relative to the internal frame. The calculation is most interesting, as it is an implicit outcome of the expression for the Planck Length, a formulation that has been around for nearly 100 years.
At this point we can then calculate the current density and temperature of the CMB, which is a function of the measured age of the universe (nTu mf) (Eq. BH.4). Present universal age is the limiting parameter which affects precision. We use a measure which has a precision of five digits. Naturally, there are several measures of universal age, some equal some with less precision, but what is important is that we directly identify the source of the measurement constraints, thus addressing the precision inquiry. With this, the remaining terms include the radiation constant (Eq. BH.6), which in turn produces the CMB temperature (Eq. BH.7). All remaining terms have more significant digits.
Precision is an important and understated quality of the calculation. Developing a method which can be identified as from 'first principles' implies also that there exists the least of inputs and fundamentally no other approach with a finer description and therein potentially greater precision.
Lastly, we draw attention to the unique qualities of this derivation. In short, using the elapsed time associated with the quantum epoch and the fixed rate of universal mass accretion, we can derive the accumulated mass/energy during this period, which in turn becomes the CMB. The approach is straight-forward, explaining where the CMB comes from, why its density is as it is. thus why its present-day temperature is as is, and what physical principles were involved that ended the quantum epoch and began the expansionary epoch. Moreover, the solution integrates the internal and system frames of the universe in such a way as to provide an consistent description of the universe across the quantum, macroscopic and cosmological domains.
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Deriving the Cosmic Microwave Background (CMB) temperature from first principles involves understanding the physics of the early universe and the properties of the CMB. Here’s a high-level overview:
  1. Big Bang Theory: The Big Bang theory predicts that the Universe was once much denser, and as a result, hotter. The CMB is understood to be the radiation emitted by the universe at an early period of its history.
  2. Decoupling of Matter and Radiation: At about 380,000 years after the Universe came into existence, the temperature everywhere was about 3000 K. The entire Universe was still a fairly dense soup of simple nuclei, free electrons, and photons. As the temperature dropped, however, the electrons were eventually able to bind to nuclei, forming neutral atoms, mostly hydrogen and helium. Neutral hydrogen and helium gas do not interact strongly with 3000 K photons, and so the Universe became mostly transparent at this time.
  3. Redshift of the CMB: Observations of the CMB tell us that it formed at a redshift of z = 1100. The observed temperature of the CMB today is 2.73 K.
For a detailed mathematical derivation, you can refer to the paper published on Jan. 25, 2023 in the International Journal of Geometric Methods in Modern Physics. Unfortunately, I don’t have direct access to the paper, but you should be able to find it using the DOI you provided: 10.1142/S021988782350069X. The relevant sections are in Appendix BF-BH. Please note that understanding the derivation might require a background in cosmology and mathematical physics.
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After several trials 1% of admixture is fixed and in such case can we put 0.6% admixtures in starting time and remaining 0.4% after sometime(maybe 2hrs later) such that workability of concrete remains good for longer time. Actually i want to clear can we put admixtures two times in a concrete?
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This will be a difficult task from a technological point of view. The plasticizer should be added to the mix together with the mixing water so that it is evenly distributed throughout the mix. There is a risk that if you have already prepared the mix (cement with water and the first portion of the admixture), when you add the second portion of the admixture to the mix, it will not be distributed in the same way throughout the entire volume and then it may turn out that the hardened composite microstructure is not homogeneous. Especially with large volumes of the concrete mix. In a small mixer in the laboratory it will probably be mixed well, but what about a large mixer on a construction site?