Science topic

Plasma - Science topic

The residual portion of BLOOD that is left after removal of BLOOD CELLS by CENTRIFUGATION without prior BLOOD COAGULATION.
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Dear friends;
What is the titratable acidity of plasma in butter?
How can I measure?
Thanks in advance.
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First you should determine fat content in butter. The rest is butter plasma. Example: fat content is 80% (butter plasma is 20%) and total acidity is 0.05%. The acidity of butter plasma is 100*0.05/20 = 0.25%
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Hello everyone, I'm a graduate student. Now I'm doing GaN etch with Cl2/BCl3 gas (ICP-RIE) with GXR601
When the etch depth is under 100nm, the surface (PR X) is clean but up to 200~300nm the surface become very rough and some mark on it. I want to know reason of this... I do soft bake 90C 1min, PEB 110C 1min, Hard Bake 110C 1min 30sec.
Thank you for answer.
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How long ago was your last chamber cleaning? This might be due to redeposited material from the walls crumbling off and flying around in the plasma.
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Need to detect 3-methylhistidine in plasma using PDA detector on HPLC. Need advice regarding how to go ahead with the method development. Suggestions on derivatization procedure. Is it possible to analyse on GC-MS (single quad) - EI mode?
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manufacturers instructions: 100μl serum (or plasma)
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It can vary depending on which kit you are trying to use.
But the range is anywhere between 50uL-5000uL.
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Hi there! I made a huge mistake yesterday, and I think that my plate is likely trash at this point, but hoping that this is salvageable. Yesterday I made a huge mistake and forgot to dilute (1:5) my human plasma samples before running my CRP ELISA. Of course, I only realized this when I added the substrate solution and the colour developed much darker than the upper standard. Obviously, the calculated concentrations are not really accurate out of the standard range, but when I divide them by 5 they are all in range and are comparable to the concentrations on my other CRP plates. Has anyone dealt with this before? Thank you!
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Thanks Malcolm
This is unfortunately what I thought, but thank you for confirming! Back to the lab.
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Related to,
Nucleus
Mitochondria
Plasma
And etc.
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the cell become shrink and the chromatin condensed
Disassembly of organelles.
Fragmentation of cells and Degradation of DNA, ill defined surface of the cell
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Hi everyone
Considering a magnetized plasma with non-isothermal electrons ( free and trapped electrons ) what is the influence of the magnetic field on the electron capture (trapping)?
and what processes are used to determine the proportion of captured electrons?
Thanks
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Actually the variation in magnetic field strength acts as magnetic mirror and causes trapping of charged particle.
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An article by Calvaresi et al. mentioned the use of lithium heparin for plasma hemoglobin assays.
(Reference: Calvaresi, E. C., La'ulu, S. L., Snow, T. M., Allison, T. R., & Genzen, J. R. (2021). Plasma hemoglobin: A method comparison of six assays for hemoglobin and hemolysis index measurement. International journal of laboratory hematology, 43(5), 1145–1153. https://doi.org/10.1111/ijlh.13457)
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Hi Carine
Plasma Hb can be accurately measured in samples with other anticoagulants, e.g. EDTA, citrate, etc. Lithium heparin is just one of many anticoagulants.
In clinical labs, plasma Hb is usually measured on a biochemistry analyzer instrument, along with several other analytes using the same sample. Heparin is often recommended by the instrument manufacturer because it is compatible with some of the other analytes also being tested in the sample, such as pH. Choice of anticoagulant is therefore dictated by these other circumstances, not by a specific biological requirement of the plasma Hb assay.
The article that you referred to was actually comparing 6 different assays/analyzers, not different anticoagulants. The important consideration is sample consistency - so use the same anticoagulant (and blood processing/handling conditions) for your entire set of experiments.
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Hi all,
I am trying to find a protocol for cDNA library preparation. The problem is that we have to extract RNA from a very low volume of plasma/serum (less than 1mL. Since we are only using 1mL of blood, the starting volume of plasma/serum will probably be in the ballpark of 500 uL). We usually use NEB library prep and Qiagen for RNA isolation. With the latter, we get a decent yield but we need at least 3mL of input serum/plasma. Since most kits require at least 100 ug of input RNA for library preparation (we are trying to aim for 100 ng), we are trying to find a protocol that will allow us to use very low RNA sample input (concentration) to get a decent read without high adaptor dimer formation. In addition, any recommendation on the extraction of RNA from a low volume of plasma/serum is highly appreciated.
Thank you!
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All RNA extraction and library preparation techniques studied consistently detected small RNAs, but several miRNAs had considerably variable amounts. The relative relevance of minimizing the amount of total sequencing required, finding uncommon miRNAs, or absolute quantification should be considered while choosing the best methodology.
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Hi, I am going to start labwork for a research in a week. This requires drawing blood from patients, and then aliquotting plasma & serum into 500microlitre eppendorfs after seperation and then storing at -80 degrees celsius. (I will be using BD vacutainer plasma and serum separator tubes) However due to unavoidable circumstances (lab closing indefinitely) I will have to postpone the aliquotting part. My questions are;
a) is there any method to keep plasma and serum in those PST and SST tubes itself (refrigerated or frozen) for sometime?
b) Or is it okay to take plasma and serum into separate EDTA tubes and store frozen at -20 degrees celcius (or a higher temperature), so that i can thaw them again to aliquot later?
Really appreciate any advices..
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Fresh frozen plasma to store in approved freezers at less than -30°C. It is thawed just before use (a process which takes up to 30 minutes) and once thawed, must be infused within 24 hours if kept at 4°C (or 4 hours if kept at room temperature)
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I do not think that there is a consensus and I would like to collect opinions on the more reliable soluble platelet activation marker in plasma.
Thank you
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A reliable plasma marker of platelet activation: does it exist?
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I want to use the plasma method to etch a superhydrophobic structure on thef Teflon surface. I have tried to process it according to the parameters in several papers, but I have never gotten it. I don't know what the core problem is?
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Yes, I know. We do this with the help of low-temperature "cold" plasma =
V. Tikhonov, etc. "The Low-Cost Microwave Source of Non- Thermal Plasma," 2020 7th International Congress on Energy Fluxes and Radiation Effects (EFRE), Tomsk, Russia, 2020, pp. 596-599, doi: 10.1109/EFRE47760.2020.9242089.
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As we know oxygen rf plasma is rich in terms of O(-) ion density. I want to understand how / what way these negative ions contribute to surface modification of substrate kept on powered electrode. do these negative ions reach to substrate surface and engage themselves in any phenomena or they remain in bulk plasma only ?
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thank you ...
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Does anyone have a protocol to isolate fibrinogen from human plasma using cold ethanol
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Following article will help you
WO2001048016A1 - Separation of fibrinogen from plasma ...
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We know the MHD such as the NTM ,Kink mode would affect the confinement or the transport of the plasma in TOKAMAK.They have different driven free energy but not only that.In general, the MHD will be onset during the RF power or the NBI injection if we put them in during plasma ramp up phase.So are there any methods to avoid those ?
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I know avoid the rational surface generated in the plasma during rampup, but how to control that as possible as to realize perfectly?
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To better explain, we are hoping to measure some proteins in plasma, however the blood shipped to us is frozen in normal eppendorfs. Will it be possible to extract plasma from this, for example by adding EDTA or equivalent now, or will we have to stick with serum? Any advice would be appreciated.
Thank you,
Mairead
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Frozen temperature is -40 degree centigrade. At this temperature RBCs get haemolysed . You can store RBCs intact at 4 degree centigrade. Batter you should transport Plasma or serum.
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similar thing also happens in Lorentz oscillator model , near resonance anamolous behaviour i.e permitivitty(-ve) and refractive index(less than one) were ocurred, my question what is the physical reason behind this anamolous behaviour?
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There are some reasonable discussions presented, right on your question.
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Coenzyme q10 is available in Reduced and Oxidized form
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thank you
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Hi everyone,
I have been working on ICP calibration. The curve got bulged and the RPDs of the lower calibration stds are sitting at +10-20%.
I tried to calibrate with different combination settings (Plasma, Neb and Sample rate).
The “best” setting for Neb is 0.5-0.6; Sample Intake is 0.75; Plasma Flow is 11.
What I have been doing is to try to get a less bulged calibration curve, so my ICV and CCV pass.
Yesterday I moved the shear gas slit closer to the torch, but I did not see any improvement.
ICP Avio 550 Max. Cal Stds are 0.02, 0.1, 0.5, 2 and 4ppm. I have re-prepped all stds three times and have them verified on another instrument.
Please advice.
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ICP-OES is fairly robust, it seems unlikely that 80 mg of metal /L (4ppm * 20 metals) would overload the plasma. Perhaps one instrument is more sensitive (newer detector, different component specifications etc). Or the lens of one instrument is dirty and not letting as much signal into the mirrors etc.
Can you examine the raw data (counts per second) for both instruments? Maybe that will tell you which one is sensitive (or losing sensitivity) for a particular element x concentration combination.
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Looking forward to the dynamics of plasma - electric field distribution.
and evaluating the forces in plasma - PCVD- nano particle distribution.
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You can reconstruct you reactor geometry with an FEM software, e.g. Comsol, in order to get this information. Colleagues from our institutedid that e.g. in this work for an MW+DC plasma (see fig. 6):
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Hi everybody,
I'm about to extract HBV-DNA from plasma. I have modified some homemade methods that are regularly used for Human genome extraction. But I could not get enough DNA for positive plasma samples. I also had a problem with a high concentration of proteins in plasma. I tried a high concentration of NaCl (6M), but it couldn't precipitate even 50% of proteins. I just have seen this problem with serum samples. Maybe it is because of the high protein concentration of plasma. By the way, I also don't want to use the phenol/chloroform method.
Who can help me?
Thank you for your consideration in advance
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Thank you both, dear Paul Rutland and Keyla Santos Guedes de Sá
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Dear ResearchGate community,
Looking for expertise in the use of dialysis for metabolomic sample prep. Ideal scenario: isolate 300 microliters of plasma, set up dialysis against ~50 microliters of receiver fluid (water or saline), wait, and harvest the 50 microliters of receiver fluid. The receiver fluid would be enriched in mobile, ionic metabolites - ideally their concentration would be 86% (300/350 x 100%) of the original plasma concentration.
Can this scenario work in practice? I've found membranes with nominal pore sizes suitable to do the job, but this application is so different from the "normal" one (depleting protein-rich solutions of contaminants) that I sense there must be some special considerations...
Or is as simple as mounting a 10K membrane in a suitable custom cell (dimensions for these quantities?) and forging ahead?
Thanks for any thoughts. They are much appreciated.
-Tony
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Scusami non riesco a capire se sei un infermiere o un tecnico. La percentuale dell' 86% è solo per alcuni ioni (in teoria) non analizziamo pìù il bagno di dialisi in uscita da anni.
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My work focuses on surface functionalization using an RF plasma system where we use argon and oxygen gases with flow of 5lpm and 15 sccm respectively. I got to know that the degree of oxidation is quite less... for which I guess Ar gas is responsible as it serves as a reducing gas (because it obstructs the oxidation process by oxygen) I just want to understand am I thinking in the right direction? or is there some other role of Ar gas except producing excited Ar species and keeping the inertness of the system? Or what is the major role of Ar gas in RF plasma system for surface oxidation?
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Thanks a ton Mikhail Yu. Yakimov it was of great help to read from those references!
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Can you help with the issue of a better kit for the depletion of more abundant proteins (albumin, and all immunoglobulins) in the plasma of mice for use in proteomics analyses? Thank you very much.
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If you afford to use it, try the Multiple Affinity Removal System (MARS) from Agilent. Mouse Multiple Affinity Removal Columns and Cartridges are ready-to-use columns for simultaneous removal of major 3 interfering proteins Albumins, transferring, and IgG. Otherwise, you need to follow a relatively cheap, tandem and, long procedure as Dr.Wolfgang Schechinger indicated.
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I've been attempting to quantify rat plasma cytokines following a mild infection. The low concentrations of the cytokines has made this very difficult using ELISA/LegendPlex techniques (I'm not detecting anything for the vast majority of my targets).
Does anyone know of a more sensitive technique to do this? I thought of using mass spec but this is expensive and I'd like to keep costs down if possible
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Did company suggested any positive controls, and did you use them, were you able to detect positive control
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Hello everyone,
We are desperately trying to get bands for PCR utilizing cell free plasma DNA extracted from cancer patients. After Bisulfite conversion, the PCR did not show any band. What could be the reason for that?
Best regards,
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Thank you Sergei, very insightful!
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I am trying to deposit NiFe using RF magnetron sputtering. But the film deposited on the substrate has rainbow colors (deposition time 1 hr.) not the silver which should be. For small deposition duration, there is no significant deposition on the substrate. The deposition parameters are- Power- 200 W, High vacuum- order of 10^6 mbar. Working pressure- order of 10^-3 mbar.
The plasma forms looks pinkish near the surface of target and bluesish above. Please suggest what should I change/consider while depostion.
Thanks
Pinki
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Well, for CF-sealed UHV systems they are removed by baking the system for two days or so. However, I assume your system is viton-sealed, right? Viton does not survive very high temperatures.
Additionally, some of the dirt will end up on either your target or your substrate, so you will still have contaminations. In my setup (with loadlock), I coat 3-5 dummy substrates before I even think about introducing an actual high-quality process wafer...
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What is the difference in measuring glucose in whole blood, serum or plasma? Are the values ​​in serum and plasma higher?
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All are equal
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I'm planning on a project to analyze label-free proteomics between plasma samples. My institution currently possesses two MS/MS types: IT-TOF (Shimadzu) and QqQ. According to my understanding QqQ is widely accepted for running quantitative proteomics. However, I cannot find much information on this type of project regarding IT-TOF. Can anyone provides the information on:
- IT-TOF performance on quantitative proteomics
- Which type of LC-MS/MS is better for performing quantitative proteomics. IT-TOF or QqQ
Best regards
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Hi,
I'd say that if you're planning to run a targeted proteomics approach, so knowing what proteins/peptides you're aiming for, the triplequad will be the best (most sensitive) option for quantitative purposes.
In case you're trying to map as many proteins in your samples as possible (untargeted) however, the ion trap might be favorable.
Hope this helps!
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I'm working on using plasma for surface modification and need to identify the active species produced in the plasma. I'm sure that ozone is also produced in the plasma but using OES i can't find O3 peaks. Can someone tell me why is it so? I know using FTIR i can find ozone peaks but my challenge is I'm using atmospheric gas phase rf plasma system.
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Significant formation of ozone only happens under very special conditions, it's not implausible that you happen to use conditions which don't generate it. If you are operating a plasma, your pressure is probably pretty low, so both educts, i.e. atomic and molecular oxygen, are not highly concentrated and therefore the formation rate of ozone can be expected to be very low while the dissociation rate is probably high since, after all, you're in a plasma. When we were wondering if ozone was formed in our plasma back when I was using atomic O in my PhD thesis, my supervisor did some calculations building on these papers to justify it as negligible:
although I think he did some sort of extrapolation back then, at least that's what he wrote in the supplement of our paper:
see section 3.
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Why isn't the Blood Urea test referred to as the Serum Urea test like the Serum Electrolytes or Serum Creatine, et cetera tests? Why the term Blood is used?
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In the US and a few other countries, plasma or serum urea concentration is expressed as the amount of urea nitrogen. Although plasma or serum is used for the analysis, the test is still, somewhat confusingly, commonly referred to as blood urea nitrogen (BUN), and the unit of BUN concentration is mg/dL.
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In a recent study, I used a nozzle structure that raises the temperature and density of electrons in the plasma. Which has greatly increased its effect on the treatment of cancer cells.
Many articles have discussed the effect of particle density on plasma interactions.
The question is how the temperature of the particles affects the interaction of the plasma with the cell culture medium or the direct interaction of the plasma particles with the cell.
In other words, which plasma factor is amplified by the increase in particle temperature?
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I think you just got confused with my statement which was just about a particular situation where higher electron temperature does not necessarily mean higher reactivity of electrons. That is when plasma is generated in flowing fluid (gas, liquid or mixture of both). In such cases with increasing fluid flow rate, electrons do not have enough time to interact with gas molecules and energy gained by them from applied field is not efficiently dumped into plasma. Thus their temperature remains higher. You will find lot of research papers on increase in electron temperature with increasing gas flow rates. So one can infer that if electrons have not undergone enough collisions, there will be less number of reactive plasma species as well because generation of reactive plasma species depends directly on electron collisions. Thus indirectly this will mean less plasma reactivity. However if one gets plume of such plasma outside of the plasma generation system on to a cell, higher electron temperature will have its effect on cell structure. But if electrons undergo large number of collisions inside plasma, they will impart their energy to other plasma species. Thus their temperature will lowered. In such cases your will have higher plasma density and also higher reactivity and higher gas temperature (temperature of plasma particles other than electrons).
Hope my answer will satisfy you this time.
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We are interested in measuring total ApoB in triglyceride-rich lipoprotein fractions from plasma from our human subjects by ELISA. Would like to hear any recommendations for the ELISA kits available for this purpose. Thanks!
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General ELISA kits should be able to detect plasma. You can try the following two ELISA Kits from CUSABIO:
Mouse APOB ELISA kit (Catalog No.: CSB-EL001918MO)
Chicken APOB ELISA kit (Catalog No.: CSB-EL001918CH)
You could search the catalog numbers on the website https://www.cusabio.com/ to view specific product information.
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I am trying to fractionate virus from plasma into different densities by sucrose gradient but we only have fixed angle rotors...
Has anyone tried doing that with a fixed angle?
Should I use the same g force and time used for same experiment with SW rotors?
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While Drs. Nobre and Steinbruck are theoretically correct, practically the answer is more complicated. Sucrose density separations can be achieved in fixed angle rotors. While swinging bucket rotors offer the best separations of proteins, viruses and DNA; fixed angle rotors may provide SUFFICIENT separations of these molecules depending on your specific application. You should consult,
"Density Gradient Separations in Vertical Tube, Near Vertical Tube, Fixed Angle, and Swinging Bucket Rotors: A Comparative Study" American Laboratory an application note posted 9/1/2007.
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I am planning to switch my media from Ad DMEM-F12 to Human Plasma Like Medium (HPLM) to grow our human pancreatic tumor organoids. Few components are different in these 2 medium and I would like to know how do these differences matter? Do I have to add in a few things into the HPLM to make it function as a replacement for Ad DMEM F12?
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I have the same interest in using HPLM for organoids and found the following paper after hearing the first author speak today. Hope it helps.
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Am working on quantification of exosome HIV chemokine receptors using ELISA. Please which method is right to isolate the exosome from plasma sample?
Thanks
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We tried using the following kits for serum-derived exosomes isolations & we chose to use 2nd one.
  1. https://www.systembio.com/smartsec-ht-ev-isolation-system-for-serum-plasma
  2. https://norgenbiotek.com/product/plasmaserum-exosome-purification-kit
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Hi, I'm a student so please bear with me as much as possible. I am measuring plasma acetaminophen levels using HPLC. My samples were in a -20 freezer which went down. They were discovered at +2C and were thawed at this point. They were placed in another freezer. We are using HPLC to measure the plasma AAP levels, so these samples will be thawed again prior to extraction and analysis. Is this going to cause a significant problem?
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Thank you kindly.
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Hi,
I would like to analyse 8-dihydroxy ergotamine in plasma by LC/MS. I need to increase the LLOQ and for this reason I need to derivatize the molecule. Does anybody have experience with these kind of molecules? I do not know if there are options....
Thanks a lot for your time and help
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Mrs/Miss Enriqueta casal-banciella
There is not needed derivatization-step.
Please, concentrate on the content on the work (ref. [1]) cited in the following discussion, when it is appeared online available:
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Hi everyone,
For my thesis, I am investigating the effects of MDA and 4-HNE in seminal plasma in male patients undergoing IVF, and thus determining if certain levels of MDA and 4-HNE effect IVF outcomes. We are measuring MDA using TBARS assay kit (Cayman Chemical #700870), but we are struggling to find the lipid peroxide level (expressed in terms of MDA) normally found in seminal plasma in published literature. The Cayman Chemical protocol states the normal lipid peroxide level in plasma is between 0.26-3.94 μM, but we are hoping to find a range specific to seminal plasma.
Any help would be greatly appreciated!
Amber Birdthistle
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Hola
If you can read spanish I suggest this paper:
Saludos
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I am calculating electron number density using stark broadening profile. while elemental detection of two samples, i found no change at between two samples. But plasma temperature and electron number density of both samples are quite different. what can be reason behind it?
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You may observe different intensities of similar transition lines in both samples. This is due the different average kinetic energy of plasma species, which is why their temperature and number densities are different in both samples.
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I've been working on the development of rapid tests using whole blood, but I'm having difficulty to create a barrier in the red cells and separating just the plasma; the nitrocellulose membrane gets a little bloody. I've already treated the sample pad with 5% PVP on PBS1X, it reduced the blood flow, but it's still not ideal. I wouldn't want to use a membrane to separate the plasma. I would like to do a sample pad treatment. can anybody help me? Thanks
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Dharliton Soares Gomes thanks, but I would like to have a specific treatment to stop of the bood cells in the sample pad, because I need only plasm in contact with conjugate pad.
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I am looking for a reliable and sensitive AMH ELISA for use with rat serum (and potentially plasma). Recommendations are welcomed! Thank you in advance.
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Maybe the Rat anti-Mullerian hormone (AMH) ELISA kit from CUSABIO is the one you are looking for. It was cited in 25 articles. For more details, please check it at:
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More specifically, I want the comparison in wavenumber-based power spectra, opposed to frequency-based. That would include converting multiple signals into a cross spectrum, finding the phase, and then the final conversion to wavenumber.
Extra points if it is in the field of plasma physics and magnetic signals.
Thanks in advance!
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I would recommend and references within. There is a reasonably extensive discussion in the first Sections including Fourier--Wavelet Comparison (with pointers to selected literature).
Best Regards
Alexander
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Why the values of the intensity ratio of doublet spectra of the laser-produced plasma spectrum differ from the theoretical value of the intensity ratio given in NIST data.
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It may be the result of line absorption in plasma.
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Goodmorning! I need to se up a plasma ELISA assay. Once I put the plate in the plate reader and I obtain the results, what is the next step? I will first do the standard curve and a few samples with different dilutions, but then I do not know if I need to convert the numbers I obtained from the plate reader.
Thanks in advance!
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Once you put the plate in the plate reader and obtain the results (absorbance), you do the following.
You will obtain the absorbance readings (OD) from the plate reader. So, initially you need to subtract the absorbance value of the blank from the standard, the assay background control, and the sample values prior to creating the standard curve. Then you plot the standard curve with the absorbance values of the standards on the Y-axis and the concentration of the standards on the X-axis. Then with the help of the absorbance value of your diluted samples obtained from the plate reader you may obtain the concentration of the diluted samples from the standard curve. The absorbance value of the sample on the Y-axis corresponds to a concentration value on the X-axis.
The concentration of your diluted samples should fall towards the center of the curve as this area is the linear portion of the standard curve in which analyte concentration can be determined accurately. Concentration should not be extrapolated from the standard curve beyond the recommended standard range as outside this range the standard curve is non-linear. Samples for which the absorbance value exceeds the highest point of the standard range should be re-analyzed at a higher dilution.
Since you have diluted your samples, you need to multiple the concentration of the diluted sample with their respective dilution factor in order to obtain the final concentration of the analyte in the original undiluted sample.
Best Wishes.
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When DC voltage bias is very high, plasma intensity is very low, and vice versa.
I'm not able to get deposition.
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Hi Nitesh Singh. I am not as expert as Sir Jürgen Weippert, but since I am recently going through these types of problems, maybe we can solve the problem together.
For the deposition, stable plasma is necessary. The plasma stability depends on the bias voltage, but along with it, it also depends on the proper flow of gas. Therefore check if the gas flow is stable or not.
As recommended by the Engineers of our system, you must check the connections not only outside but also in the system. If possible, check for grounding also. Is it proper or not?
As already stated by Jürgen Weippert Sir, the matching network only fixes the reflected power (in our case also). The DC supply adjusts itself while obtaining plasma. Therefore, you perform the matching for low reflected power only and try to get stable plasma.
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I used the brain, plasma and serum sample of rats. Preparation of the samples were done on ice bath and centrifugation done at 4 C, then the supernatants were kept in -20 C. the test was done with in 7 days. The brain samples gave satisfactory results on lipid peroxidation test (using 20% TCA and 0.67 TBA). However, plasma and serum samples did not produce any color at all, what cause the absence of colour in these samples?
ps: I also have tried different preparation for the plasma, using citrate and EDTA.
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In laser-induced plasma spectra, an element usually has multiple lines corresponding to it. In theory, how to determine which lines are most likely to excite? In addition, there are two elements in a sample with the same content, the same energy level, the same transition probability. Why are atomic lines detectable for one element and not for another?
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The NIST LIBS database is a very useful resource in predicting what lines should be present in a plasma (https://physics.nist.gov/PhysRefData/ASD/LIBS/libs-form.html). The theory is based on the Saha Ionisation Equilibrium model which is bet suited to low temperature high density plasmas
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In Boltzmann equation the balance of electron flux in energy space for the de-excitation reaction [ e + A* => e + A ] defined as:
R(eps - eps*) x n(eps - eps*) - R(eps) x n(eps) = 0
where
eps* - is the negative treshold energy of corresponding excitation
n(eps) - electronenergy distribution
R(eps) - is the reaction rate
R(eps) = (eps + eps*)/eps x sigma(eps + eps*) x v(eps)
Excitation and de-excitation rates are defined in the same way
R(eps) = sigma(eps) x v(eps)
My question is, which of these definitions are correct, or are they equivalent?
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Good Luck.
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Hello
For a biomarker study in neurodegeneration, we are searching for publicly available data of unique molecular identifier (UMI) counts of microRNAs in plasma from non-neurodegeneration individuals.
Do you have these data by any chance or can you refer me to a database where I can find such data?
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The plasma was in a cryogenic tube with a volume of 500ul and previously stored in -80C freezer for months. I would like to know how long does it take to melt at room temperature? Does anyone have related experience to share? Thanks!
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James Garry Thanks James! I may not melt the sample in the room air, probably on the ice to slow down.
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Hello,
I am currently working on a protocol for the isolation of extracellular vesicles from plasma (0.8 mL). For this I am doing an ultracentrifugation with discontinuous density gradients with Optiprep diluted in 0.25 M sucrose buffer for 24h at 182 000g, as suggested by Karimi et al., 2018 (https://doi.org/10.1007/s0001 8-018-2773-4). From a starting volume of 5 mL, I collect 10 fractions of 0.5 mL for further analyses. In particular, I would like to measure the density of each fraction. I tried to measure their absorbance with a Nanodrop-One at wavelengths of 244 nm and 340 nm as suggested by Li et al., 2018 (doi:10.1007/978-1-4939-7652-2_7.) and Onódi et al., 2018 (doi: 10.3389/fphys.2018.01479). However, the absorbances found do not match the expected theoretical absorbances. For instance, 2 µL for 70 % optiprep (42% iodixanol), 40% and 10% solutions, absorbances of 13, 5.2 and 1.25 are measured instead of expected absorbances of 0.772, 0.44 and 0.112, (as described in the Optiprep application sheet S09).
How can we explain these important differences in absorbance values ?
Thanks in advance.
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Hi Alice, I'm facing the same problem as you mentioned above. If you figured out why there is a descripancy in mentioned OD and what we see kindly help me. THANK YOU
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Greetings,
We have a small project in which we try to isolate brain cell-originated extracellular vesicles (EV) from serum/plasma. We are trying to use immunoprecipitation approach to isolate cell specific EVs; however, we need some help to formulate an gentle elution conditions since we need to analyze those intact EVs. Any help and advice are much appreciated.
regards,
Baki
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Thank you Jorgaq !...
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I am interested in understanding how heavy particle temperature and electron temperature are experimentally measured in nanosecond laser-generated plasmas during the discharge phase (i.e., when the laser is still on). In particular, I would like to know if the measures are line-average (or volume-average), or if it is possible to map the full 3D temperature fields as a function of time. Thanks.
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Hello, Andrea
You cannot measure the temperature using OES during the breakdown event because it relies on the Boltzman LTE assumption which is not necessarily true.
A better method for measuring temperature (electron, vibrational, rotational, translational) would be through laser scattering methods: Thomson scattering for Te, Raman scattering for (Tv and Tr) and Rayleigh scattering for T. This is not an easy measurement to perform but I'm hoping to measure Tv and Tr during breakdown over the next few months to at least be able to tell you how far/close we are to thermal/equilibrium plasma during breakdown.
I don't know if this helps too much. Unfortunately we are still lacking detailed measurements during the breakdown phase.
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I was trying to image PDMS gels with AFM. I was not able to get any proper picture of the substrate, there was false engagement and noise. The substrate is plasma treated and coated with collagen. Any suggestions?
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There are many, many possibilities... It is quite rare, but you might have static charges on the PDMS and on the tip. They can exert very high repulsive forces.
Another problem could be a very thick and extremely soft collagen layer, almost liquid - not likely, is it?
Assuming you worked in noncontact/oscillation/tapping, I would mount an old (i.e. cheap) tip, switch to contact mode, and approach at very high setpoint force. The tip might well penetrate the collagen, but not the SiO2 layer (the plasma-treated top surface of your PDMS), and you should obtain some (poor) image. Maybe a starting point for troubleshooting.
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Hi there, I've been trying to fractionate small proteins from the large/abundant proteins in plasma using the 0.5 mL MWCO 30 kDa filters like Amicon. Yet, when I for example filter 1ul of plasma (diluted to 500ul 50mM ABC or miliQ water), I don't see the small proteins in the flow through. When I apply the same method to less complex samples like a protein mix of 6 proteins or hela cells I do see small proteins in the flow through, although the recovery could have been better. When increasing the plasma amount to 10 or even 100 ul it still doesn't improve. I assume that I just clog my filters and the small proteins cannot pass the membrane. Now I plan to use the larger filters like 4 mL or 15 mL because they have a larger filtration surface. I was wondering if anyone has experience in using these filters for analyzing the flow through instead of the concentrated sample and if they can share their experience?
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Hi Roger,
Thank you for your reply! Concentration on the filters works perfectly. The solvent passes the membrane, but the small proteins don't (for plasma). There are no instructions available that specifically mention the use of the filters for targeting small proteins in the flow through. But indeed, pipetmixing might increase the recovery. Thank you for your suggestion.
Best,
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Gas chromatography, mass spectrometry and HPLC are often used in studies, which based on my received fund, these are too expensive and inaccessible. What is your Recommendation?
thanks for answering.
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We have an old Branson/IPC plasma etching unit. There is ~1/2" glass tube about 15" long that is connected from the center of the etching chamber to a metal flange that goes to the vacuum pump. Folklore says that the power lever should not be set so high as to have the plasma go down that tube towards the pump. Recently we have not been able to set the power lever above 45 watts with out having the plasma go down that tube. We have tried any number of thing, redo the vacuum connection, change vacuum pumps, replace seals, run with gas flowing, no gas flowing, change the pressure we are running. Naturally, thing are not consistent as far as what power we can apply before the plasma goes down the tube. The only thing that seem to allow us to go a little higher in power is to increase the power extremely slow. Depending on the day that will allow us to go up to 150 w. But that is not consistent from run to run. I have two questions. Does it hurt to have the plasma go down the glass tube? We only use an oxygen plasma and the end of the glass tube to the pump is a metal pipe. If we wrap some metal screen or aluminum foil around the most of the tube and ground the foil, will that stop the plasma in the tube? As a side note we were told by a plasma chamber manufacture that they have at times put a metal screen between the pump and the chamber to stop the plasma from reaching the pump. In our case, I would expect the metal pipe between the pump and glass tube end stop the plasma before it reached the pump. Any thoughts would be helpful.
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Hi Tomn, Where ever you see the plasma is where your energy is going so if it is in your pipe it is not really in a useful place, and will probably be heating up the joints in the system.
Putting a piece of metal mesh to cover the entrance of pipe should stop the plasma going beyond it. Think of it as behaving like a piece of gauze that stops a flame passing beyond it.
It depends a bit on how the system i connected: It could work adding the mesh at the start of the glass tube, and electrically connecting it to the chamber.
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I want to separate serum from plasma( plasma is collected from from the blood collected by using anticoagulant CPDA). Plz help me out with the best method to separate it.
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Zainab Sohail ,If it is whole blood and If there is no substance that will prevent serum separation in the blood bag, you may use the same method.
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is there any commercialized cold plasma based method for processing foods(like nuts) to eliminate toxic compounds?
by commercialized I mean a role to role or any type of system that can process a very large amount of nuts
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EFFECTIVE AND ENVIRONMENTALLY FRIENDLY METHOD AGAINST AFLATOXINS IN NUTS
Researchers have tested various methods to prevent the development of mycotoxins. The application of the yeast Pichia anomala to prevent their development in nuts and maize crops is currently being studied. This method is non-toxic and could even be used in organic farming.
Tests have been carried out in a pistachio plantation in California (USA). The experts sprayed some trees with the yeast Pichia anomala and others without. The results were enlightening, as the sprayed trees inhibited the frequency of occurrence of Aspergillus flavus on pistachio nuts by 97%, compared to the unsprayed trees.
It has also been shown to be effective on harvested and stored nuts. Furthermore, the use of the yeast is confirmed to be very versatile, as it has also proven effective in protecting other crops against at least six species of microorganisms that could alter characteristics such as taste, texture, yield and food safety, including the pathogen Botrytis cinerea, which is considered responsible for grey mould in grapes.
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Hi community,
I have a question regarding the H-α, H-β and H-γ behavior in a CH4/N2 plasma.
Long story short: I am igniting a 5 sccm: 200 sccm CH4/N2 plasma (40W CCP plasma) at 5 mbar. Then I observe the plasma via a spectrometer. I did that for various temperatures inside my chamber.
Now I observe some typical Peaks. Most are related to N2 of course. And also the Balmer series.
What puzzles me is the transition from a increasing trend for the H-α and H-β lines but a decreasing trend for the H-γ line. Normaly I'd say these line can correspond to a) the density of hydrogen or b) to the mean energy of my electrons in the plasma. No hydrogen = no balmer series or no energy = no balmer series.
Clearly there is hydrogen. Most likely even more free hydrogen with icnreasing temperature. So why would the H-γ behave like it does? The energy difference between the three lines is not very big, so we should see a similar trend, right?
tl;dr: Do the three lines (H-α, H-β and H-γ) of the Balmer series have to follow the same intensity trend? Or can they show different behaviour? If so, why?
Thank you for your support :)
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Interesting thought. I can see how this could be potentially true for my plasma. Is there an easy way to measure the distribution of the electron temperatures?
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I am looking at HIV viral load in plasma samples from ART treated people living with HIV without using a commercial kit. As these samples are from virally suppressed individuals, they should have very low viral titre. I am looking for a good technique to concentrate plasma.
Thank you in advance for your feedback!
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Try dialysis. Dialysis | Sigma-Aldrich (sigmaaldrich.com)
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I am Ali Raza student of Mechanical Engineering. I am working on a project in which i have to make a hole in microwave oven and i have a few queries.
1. Which method is best for cutting a hole in oven?
Note. I tried but lasor and plasma cutting didn't work
2. Is there any difference making a hole on upper side and lower side?
If anyone know about my queries your answer will be highly appreciated
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I think where the holes are, it doesn't matter if they are up or down
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The ICP MS instrument works to shut down the plasma during the injection process (during the run) what is the reason??
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You will need to provide a lot more information to get any helpful answers.
  • What model of ICPMS, when does it occur - any sample or do calibrations samples pass and samples stop?
  • What is your matrix? High organic solvents can extinguish the plasma.
  • Are you running low on Argon? Is the gas pressure to the instrument correctly set?
  • Is there a fault with the gas settings (reaction or kinetic gases?)
  • Has the peristaltic pump setting been altered for samples vs calibration?
  • Does the system tune OK? Has anything changed?
  • Is the drain pump working ? Have you flooded the spray chamber?
Also check the PLASMACHEM-L archives run by Syracuse University. You may find some clues there. It is free to join, but please review the listserve rules before posting a question. (They aren't onerous).
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The Big Bang theory is very dependent on the observation and interpretation of the Cosmic Microwave Background (CMB) radiation. In the Big Bang theory the CMB originated from a process called recombination. We know that it is not possible to create the early conditions of the Big Bang in a laboratory environment. However, under the Big Bang theory the universe has cooled to 3000 degrees Kelvin by a time 370,000 years after the Big Bang. This temperature is within the possible range of temperatures which is accessible in a laboratory environment.
The hypothesis of the Big Bang is that the CMB radiation is coming from a time 13.8 billion years ago when the universe became transparent due to recombination (see below). Before then the universe was opaque to radiation.
It is clear from the narrative of the theory that the figure of 3000 degrees Kelvin comes from the temperature required to produce the current CMB observed temperature of around 2.725 degrees Kelvin after a redshift of 1100. The temperature has not been derived from an analysis of the properties of a plasma.
Now that we have the ability to verify the hypothesis of recombination, for example by observation of the behaviour of a plasma as the temperature drops through 3000 degrees Kelvin, it would be worthwhile to perform this experiment.
As a scientific experiment it is well justified economically since if the analysis shows that a plasma does not behave exactly in the way predicted for the CMB in the Big Bang model then there would be considerable savings in scientific research investment which is predicated on the hypothesis of the Big Bang theory lambda CDM model.
So my conclusion is that the Big Bang theory is falsifiable.
Recombination is described in Wikipedia as:
In cosmology, recombination refers to the epoch at which charged electrons and protons first became bound to form electrically neutral hydrogen atoms. Recombination occurred about 370,000 years after the Big Bang (at a redshift of z = 1100). The word "recombination" is misleading, since the Big Bang theory doesn't posit that protons and electrons had been combined before, but the name exists for historical reasons since it was named before the Big Bang hypothesis became the primary theory of the creation of the universe.
. . . .
This production of photons is known as decoupling, which leads to recombination sometimes being called photon decoupling, but recombination and photon decoupling are distinct events. Once photons decoupled from matter, they traveled freely through the universe without interacting with matter and constitute what is observed today as cosmic microwave background radiation (in that sense, the cosmic background radiation is infrared [and some red] black-body radiation emitted when the universe was at a temperature of some 3000 K, redshifted by a factor of 1100 from the visible spectrum to the microwave spectrum).
Richard
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For the discovery of the Higg's Boson the LHC created conditions that were very close to those at the moment of the BB. these conditions could only be extremely brief but had to be long enough to see if the Higg's Boson existed. Hence proving that the Higg's particle exists is also evidence for the BB and not just the CMB, besides of course, the accelerated expansion that of the universe that has been observed. these observations from the quantum to the cosmic levels make the theory of BB scientifically quite strong and very likely. unless there is a theory that can explain all these facts, in addition to new observations that will require a complete revision of the BB theory to the point that it becomes clear that changing the current paradigm is better, the BB theory will remain our best working theory for the understanding of the universe. thanks.
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Can some one guide me to some basic literature about designing inductively coupled RF discharge (preferably cylindrical). How to decide the diameter, number of turns, frequency, power, gas pressure etc. Rule of thumbs would also work if exact literature is not available. Oh yes and in presence of high external magnetic field.
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The books of Pascal Chabert and Lieberman are the primary references, of course, but in addition to that this might help :
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I want to remove EDTA from the mice plasma samples. I know that there are some dialysis cassettes available in the thermo to do it but they have not mentioned about the buffer required. Has anybody done it successfully and can share the protocol with me. Basically i want to know what kind of buffer and the time is required to do it. I want to inject the EDTA free plasma back to the mice that's why it's necessary to do it.
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You may refer to the research article attached. Please refer to Table 1 in the Results section.
Hope this will help!
Best.
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I want to analyze rat serum/plasma for IgG, M and A. I found ELISA plates for only IgG for Nucleoprotein and Spike-RBD for RATS. I failed to find ELISA plates for the other immunoglobulins.
Any suggestions please?
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Wolfgang Schechinger Thank you so much!!! I appreciate the prompt reply!!! Big help!!
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I want to coat sulfobetaine methacrylate (SBMA) monomer on plastic substrate (ex. PET, PC) using plasma.
as little details, Substrate is treated by plasma at first, and dip in the solution of sulfobetaine methacrylate in water. then, substrate is treated by plasma again. so substrate coated with acrylic monomer by plasma induced radical polymerization.
in now my environment, I can use only O2 plasma. Is it okay?
As I check using FT-IR, I can't difference between unteated and coated substrate.
um.. Do i use other analysis?
little confused
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Oxygen plasm treatment indeed is an effective way to render the surface of substrate, while it does not give a surface with a high tendency without a trigger, a heat, initiator, etc. You are going to treat your surface using oxygen plasma but at the same time you are inducing radical polymerization to your system. You might know that oxygen is radical species are strongly tend to react with oxygen and neutralize the entire system. Oxygen is considered as an impurity in a radical polymerization. So, you might need to go through each of steps once again to avoid unwonted reaction.
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Hi everyone,
I am trying to find solutions to conserve glass superhydrophobic property after it has been plasma cleaned. I've heard that the use of nitrogen might help. Do you have ideas for this problem ?
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Dear Celine,
my experience is mainly referring to float glass as for mikroscope use. After an oxygen plasma, I found some loss of weight and also some change in the alkali ion concentration by ESCA depth profiling. The weight loss was recovering quickly while on the balance, so I assume that it was water. The contact angle after the plasma was not measurable as the droplet was spreading immediately. I could not really conserve his property in the lab for longer than a few minutes and I cannot recommend to try it. Nearly any surface leaving an oxygen plasma has a very high energy and will pick up any dirt from athmosphere. This is a general finding from all my trials for plasma cleaning. A monolayer of hydrocarbons in the air/nitrogen/vacuum is enough to spoil the cleaning effect. If important, please send me an e-mail to my company (surface chemistry)
Best wishes, Heinrich
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Newton's second law, sometimes called the fundamental principle of dynamics, is usually con-
sidered as an irreducible axiom of mechanics. It is actually not a mathematical theorem, but a physical principle based on experiments on our planet. Do you think that this law would be valid in the absolute vacuum, or does it reflect the existence of some omnipresent form of aether which would explain why we need some energy to move an object in the absence of any detectable obstacle or damping of whichever nature? (solid, liquid, gaseous, plasma...)
All remarks are welcome.
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Thank you for your participation.
You may be too affirmative, since nobody ever checked that point (existence of aether) and a large part if the community thinks that it exists in some form or another, as explained in my text. My idea is that in absolute vacuum, matter transfer can be done at no expense (because the "effective mass" of nucleons is 0). The coefficient "1" in the RHS of Newton's law is artificial and corresponds to a choice of units for mass and force, related with our measures and experiments on earth. Maybe, in some distant regions of cosmos, it will be different (the "effective mass" becoming different for the same number of nucleons). This can also help to understand Zwicky's paradox (hidden mass problem).
Checking the existence of aether (or anything similar) would require very sophisticated experiments, maybe the most accessible way would be through the drag which should be perceivable by its action on moving matter, but if it exists it will be extremely weak, which makes the experimental protocol very delicate, cf. my other post https://www.researchgate.net/post/Any_idea_for_proving_or_disproving_the_existence_of_aether
Best wishes
Alain H.
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What is inverse bremsstrahlung phenonmenon in the generation of laser induced plasma?
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One of the best books explaining the mechanism of light absorption through inverse bremsstrahlung is "Physics of Shock Waves and High-Temperature Hydrodynamic Phenomena" by Ya. B. Zel’dovich and Yu. P. Raizer https://www.amazon.com/Physics-Shock-High-Temperature-Hydrodynamic-Phenomena/dp/0486420027
See Chapter V. Absorption and emisson of radiation in gases at high temperatures. Please note that when calculating the absorption coefficient of laser radiation in a plasma through the inverse bremsstrahlung mechanism together with photoionization (the Unzoeld-Kramers formula), it is also necessary to take into account the correction for stimulated emission, which in the case of laser radiation can be significant.
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We have performed RNA extraction from several samples of plasma with miRNeasy Serum/Plasma Advanced and in 1:4 samples we get this strange peak at around 3000nt. Has anyone seen something similar using this kit?
Thank you.
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are you doing DNase digestion? might be DNA contamination
are you diluting the sample prior to isolation? sometimes all the salt in serum/plasma can mess with isolation. I would dilute 1:4 -1:10 in PBS then elute in a small volume.
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I'm working with extracellular vesicles (EVs) from tumor cells injected in mice. I would like to know if it is better to extract RNA from the plasma or if I should first isolate EVs then extract RNA from those. Do you think there will be any difference between both?
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Hi Sridhar,
As I understand, you want to do a kind of "vaccination" against cancer - in other words, introduce the immune system to the cancer environment. Right? Then, you would like to see how the overall gene expression vector changes? In this case, I would isolate the RNA from the blood. Only in this case, you will have an overview.
All the Best.
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I understand that inductively coupled plasma (ICP) means inductively coupled plasma, which has coils around the dielectric wall, and reactive ion etching (RIE) uses combination of chemical and physical etching. I am trying to understand different etching techniques and I have some confusion.
Does the term ICP and CCP (capacitively couple plasma) refer to the structure of the hardware where as RIE refers to the etching mechanism? So for example, could RIE be done with both ICP and CCP (ICP-RIE or CCP-RIE)? Or Could RIE be done with only ICP?
The ICP etcher I have access to has two RF sources. So I can set RF power 1 and RF power 2 on the recipe. What are the two different RF power sources?
Please let me know if there is a good resource I can use to learn more about etching. I am having hard time finding a good resource.
Thanks!
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Reactive-ion etching (RIE) is an etching technology used in microfabrication. RIE is a type of dry etching which has different characteristics than wet etching. RIE uses chemically reactive plasma to remove material deposited on wafers. The plasma is generated under low pressure (vacuum) by an electromagnetic field. High-energy ions from the plasma attack the wafer surface and react with it producing anisotropic etching preferable in the direction of the ions.
Different types of RIE systems exist, including inductively coupled plasma (ICP) RIE. In this type of system, the plasma is generated with a radio frequency (RF) powered magnetic field. Very high plasma densities can be achieved, though etch profiles tend to be more isotropic.
A combination of parallel plate and inductively coupled plasma RIE is also possible. In this system, the ICP is employed as a high density source of ions which increases the etch rate, whereas a separate RF bias is applied to the substrate (silicon wafer) to create directional electric fields near the substrate to achieve even more anisotropic etch profiles.
An inductively coupled plasma (ICP) or transformer coupled plasma (TCP) is a type of plasma source in which the energy is supplied by electric currents which are produced by electromagnetic induction, that is, by time-varying magnetic fields. So it is a part of the RIE system.
Hope this helps. Best regards.
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For the centers used CCP, I appreciate if you share your experience for this modality of treatment and how it was beneficial vs higher mortality among infused patients.
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Convalescent plasma therapy may be given to people with COVID-19 who are in the hospital and are early in their illness or have a weakened immune system. Convalescent plasma therapy may help people recover from COVID-19 . It may lessen the severity or shorten the length of the disease Abdulsalam Al-Ani
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Dear research fellows,
I have to measure interleukin concentration in mouse plasma samples for my master's thesis. My professor would like me to sent some samples to another lab for this measurement, because we neither have the experience nor the ressources for this in our lab.
Do you know of any labs in Europe (especially in Germany) that are able to perform inteleukin concentration in mouse serum or plasma samples?
Thank you
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