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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I'm looking to measure estradiol in mouse plasma. There are several commercial ELISA kits available. My main question is if to use extraction prior to quantification or not.
Thanks
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I see some protocols mention the evaporation must be done under inert gas? is this crucial?
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What are the side effects
Of plasma applications in medicine ?
Especially in surgical applications
For example
Resection of Liver Tissue
Freeing Bowel from Abdominal Wall
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In my view, plasma medicine is still in its early research stages, and its long-term effects on human tissues remain uncertain. Further clinical trials are necessary to evaluate the potential chronic adverse effects of repeated exposure.
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I have fibrin from human plasma insoluble powder (Cat No. F5386-1G). I have to crosslink it with X compound but before crosslinking I have to make it soluble.
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Have you solved this problem? I have the same issue.
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is it Qiagen miRNeasy Serum/Plasma Advanced Kit or Norgen Plasma/Serum RNA Purification Kit ?
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I used Kia gene auton extraction kit to extract mRNA for gene expression. It is very good.
For specific details just contact Qiagene https://www.qiagen.com/us/contact-us
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Plasma drug concentration and brain distribution study
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You could try the MapleQuest PosiTIVA web app. It is free, open-source, easy to use and runs the venerable StanpumpR pharmacokinetic simulator by Prof. SL Shafer under the hood. It has PK models for propofol, remifentanil, fentanyl, alfentanil, sufentanil, morphine, pethidine, hydromorphone, methadone, ketamine, dexmedetomidine, midazolam, etomidate, lidocaine, rocuronium, naloxone, oxytocin, oxycodone and oliceridine built in, and can be expanded with your own custom plugins.
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This question is related to possibility of experimental studies of electric plasmons.
More information about theoretical part of such studies
can be found in the preprint "Materials with negative permittivity or negative permeability – review, electrodynamic modelling and applications"
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Thank you
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I must build a public system air installation project ( innocuous sterilization for humans and environments) that protects the air conditioning atmosphere layer.
so, I need to connect with 3 parts of the research. that first, classic scientific result of Plasma in Physics that "plasma treatment reasonable scientific research part". Second, the current product state of sterilization air system by plasma in the " industry part". Third, the system module that plasma sterilization treatment module process (easy and simply) "engineering system part".
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Thank you for your very kind explain. Also i need to find about the plasma purification system by semiconduct
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Would it be possible to use the magnetic confinement as used in fusion research to contain the tin plasma that produces the EUV light for semiconductor lithography?
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Using magnetic confinement to contain tin plasma for Extreme Ultraviolet (EUV) lithography is theoretically possible, but there are significant challenges involved. Here's a breakdown:
Magnetic Confinement Principles:
Magnetic confinement, often used in fusion reactors, relies on magnetic fields to control and stabilize charged particles in plasma, preventing them from coming into contact with the containment walls.This technique works effectively for high-temperature plasmas like those in tokamaks or stellarators, where the plasma consists of a mixture of ions and electrons. The magnetic field creates a "bottle" that holds the plasma in place.
Tin Plasma in EUV Lithography:
EUV lithography relies on high-energy light, usually at a wavelength of around 13.5 nm, produced by tin plasma that is heated to create EUV radiation.Tin is used in EUV sources because it emits strong EUV radiation when ionized, particularly when it's in a high-temperature plasma state (around 100,000 to 150,000 K). This is typically achieved using a laser-produced plasma (LPP) or a discharge-produced plasma (DPP) setup.
Challenges with Magnetic Confinement:
Plasma Temperature and Density: The temperature of the tin plasma needed for EUV emission is high, but it doesn't need to be as hot as fusion plasmas. Maintaining the right balance of plasma density and temperature for efficient EUV production is challenging, as magnetic confinement can interfere with maintaining the precise conditions needed for optimal EUV emission.EUV Emission and Magnetic Fields: One of the main hurdles is that EUV light (especially at 13.5 nm) is absorbed by even weak magnetic fields, meaning that the fields themselves could interfere with the radiation that needs to be captured. Magnetic confinement might reduce the efficiency of EUV generation.EUV Optics: EUV lithography systems use mirrors instead of lenses to focus the light. Magnetic fields could potentially distort or complicate the path of the EUV photons, making it difficult to capture or direct them accurately.
Current EUV Source Methods:
Most current EUV sources, like the laser-produced plasma (LPP) or discharge-produced plasma (DPP) systems, rely on creating and confining the tin plasma via other means (such as using a laser to focus on a tin droplet) rather than magnetic fields. These techniques aim to achieve the highest possible brightness and efficiency for EUV generation.
Feasibility of Magnetic Confinement:
In theory, magnetic confinement could be used to stabilize the plasma in certain configurations, but it would likely require careful design adjustments to ensure the plasma emits EUV efficiently without interference from the magnetic fields.More research and innovation would be needed to explore how to integrate magnetic confinement into EUV sources without reducing performance, particularly since other methods (like LPP and DPP) are already effective and well-developed.
In summary, while magnetic confinement is conceptually feasible, it is not currently a preferred or practical method for containing tin plasma in EUV lithography systems. The existing techniques are more optimized for high efficiency in EUV production, and integrating magnetic fields into such systems presents significant engineering challenges.
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Hello researchers,
We have plasma samples stored at -20 degrees C since one and a half year.
Are they still okay for Elisa, qPCR, or any analysis?
We need some expertise opinion, and we would really appreciate your help.
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Hello Doha Mohamad Khalifeh,
Once the plasma samples have been collected, they must be frozen within 8 hours. To ensure the quality and efficacy of plasma samples, fresh plasma samples must be frozen to very low temperatures. Plasma samples stored below -30 degree C will work for a period of one year. However, if you wish your plasma samples to last for more than 5 years, then you should store your plasma samples well below -60 degree C.
When you have to use frozen plasma samples, after thawing, you may refrigerate them at 4 degree C and use the samples within 24 hours.
I have a little doubt whether your plasma samples will work when stored at -20 degree C for such a long period (one and a half years).
Best.
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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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Remember, 90 C for 60 min
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Can one recomend any training (live or online) or webinar or something like that about plasma analysis during PVD processes, especially in terms of mass spectrometry ?
I would be very grateful for an advice.
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I am trying to determine the electron number density in my plasma by using the Saha Equation for degree of ionization. However I am slightly confused with how to determine the particle density (n = ni + ni+1) to solve for ne. Is there a standard value or...?
I presume as a first approximation I could determine the density of the gas with the ideal gas law and then use this number to approximate the density at my determined temperature. If I do so are there any obvious complications I may be overlooking?
Thanks in advance!!!!
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its a simple fractal, but not a perturbation. just run a column down Excel with line 1: ni, line 2: ni + 1, line 3: = line 1 + line 2, highlight line two and Control D two or three hundred lines. the last line is a "precise approximation."
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Dear colleagues, I would like to specifically purify an anti-HLA-A2 antibody from plasma samples of a kidney transplant patient. I believe that antigen-specific affinity purification might be the best option, but I'm not entirely sure. Does anyone have experience with this process? Thank you very much!
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Yes, antigen-specific affinity purification is a widely used technique to isolate antibodies that bind specifically to a particular antigen from a mixture. Here’s a detailed protocol for this process:
### **Protocol for Antigen-Specific Affinity Purification of Antibodies**
#### **Materials:**
1. **Antigen (for immobilization)**
2. **Affinity matrix** (e.g., Protein A/G beads, agarose or sepharose beads)
3. **Antibody-containing sample** (e.g., serum, cell culture supernatant)
4. **Binding buffer** (e.g., PBS or TBS)
5. **Washing buffer** (e.g., PBS or TBS with a small amount of detergent like Tween-20)
6. **Elution buffer** (e.g., low pH elution buffer, such as 0.1M glycine-HCl, pH 2.5-3.0)
7. **Neutralization buffer** (e.g., 1M Tris-HCl, pH 8.0)
8. **Centrifuge**
9. **Microcentrifuge tubes**
10. **Column (if using a column-based system)**
#### **Procedure:**
**1. Prepare Antigen-Coated Affinity Matrix:**
- **Couple Antigen to Matrix:**
1. **Choose the matrix**: Common matrices include agarose or sepharose beads. For most applications, Protein A/G beads are also used.
2. **Prepare the matrix**: Swell the beads in the coupling buffer (usually a carbonate-bicarbonate buffer, pH 9.0, for antigen coupling).
3. **Couple the antigen**: Incubate the antigen with the matrix according to the manufacturer's instructions. Typically, this involves incubating the antigen and beads overnight at 4°C with gentle agitation.
**2. Block Unreacted Sites:**
- After coupling, block any remaining reactive sites on the matrix to prevent non-specific binding. Use a blocking solution, such as 1-5% BSA in PBS, and incubate for 1-2 hours at room temperature or overnight at 4°C.
**3. Wash the Matrix:**
- Wash the matrix with several volumes of PBS or TBS to remove any unbound antigen or blocking agent.
**4. Bind Antibodies:**
- **Add Antibody Sample**: Incubate the antibody-containing sample with the antigen-coated matrix. This is typically done by gently mixing the sample with the matrix and incubating at 4°C for 1-2 hours or overnight with gentle agitation.
- **Volume and Concentration**: Adjust the volume and concentration of the antibody sample according to the amount of antigen on the matrix and the expected antibody concentration.
**5. Wash:**
- After binding, wash the matrix with multiple volumes of washing buffer (e.g., PBS or TBS with 0.05-0.1% Tween-20) to remove non-specifically bound proteins. Perform several washes until the flow-through is free of unbound antibodies.
**6. Elute Specific Antibodies:**
- **Elution**: Elute the specifically bound antibodies using an elution buffer. Typically, this is done with a low pH buffer, such as 0.1M glycine-HCl, pH 2.5-3.0. Collect the eluted fractions in microcentrifuge tubes.
- **Neutralize**: Immediately neutralize the eluted antibodies with a neutralization buffer (e.g., 1M Tris-HCl, pH 8.0) to prevent denaturation or damage to the antibodies.
**7. Concentrate and Store:**
- **Concentration**: If needed, concentrate the antibody solution using a centrifugal concentrator or other suitable methods.
- **Storage**: Store the purified antibodies at -20°C or -80°C for long-term storage. For short-term use, they can be kept at 4°C.
**8. Validate Purity:**
- Verify the purity and specificity of the purified antibodies using techniques such as SDS-PAGE, Western blotting, or ELISA.
### **Notes:**
- **Antigen Coupling Efficiency**: Ensure that the antigen is coupled efficiently to the matrix by optimizing the coupling conditions.
- **Matrix Choice**: The choice of matrix can affect the binding and elution conditions. Always follow the manufacturer's recommendations.
- **Buffer Conditions**: Buffer composition can significantly impact the efficiency of binding and elution. Adjust buffers based on the specific properties of your antibodies and antigens.
By following this protocol, you should be able to perform antigen-specific affinity purification effectively, obtaining purified antibodies with high specificity to your target antigen.
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I have been getting a low plasma and no coating while doing rf sputtering of copper doped ZnS using a power of 140 watts and at pressure of 6.5x10-3 Mb.
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1. Check the magnetron (position of magnets behind the target).
2. Try increasing the working pressure.
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I am running a logistic regression analysis exploring the association between Alzheimer's Disease (AD) status (outcome) and plasma biomarkers of AD (predictors), namely, Ab40, Ab42, the ratio, as well as p-tau217 and p-tau181.
However, I have all the plasma AB measured in pg/mL, p-tau217 in u/mL, and p-tau181 in ng/L.
How can I convert these units to make them comparable?
I know there is a 1-to-1 correspondence between pg/mL and ng/L, but do not necessarily know what to do with u/mL.
Many thanks in advance!
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Thank you very much again!
Since the model then had very poor fit, I did start questioning whether the transformations I applied were sufficient. However, standardizing the data (raw, not log-transformed) did not seem to improve things a lot, so it must be that my predictors simply do not 'predict' my outcome very well.
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Hi all,
I was wondering if people here have any recommendations on ELISA kits they've used and validated to quantify cfos protein levels in a biological sample.
Ideally using brain, but if it worked in your hands for brain, cells or plasma, please let me know what kit brand you used. I used one from AFG and was not very happy with the results.
Thanks
Mario
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Hello, I am an Etch Engineer.
I am performing etching with high T_ox/Nit selectivity using remote plasma.
Etching plasma is formed using only NH3/NF3/H2.
1. I wonder if it would be advantageous to add Ar or N2 as inert gas to increase the stability of plasma. (There is an ion filter, but I am concerned about damage caused by Ar)
1.1 Additionally, it is said that inert gases help maintain plasma density, but only the radicals of the reactive gases react, not the electrons or ions needed to form plasma. Is there a difference?
2. I suspect Nit etching due to F radicals when using that gas. I am curious about a way to reduce the concentration of F radicals. (Additional process gas, ratio, etc.)
3. Is there a pre-treatment process that can reduce Nit etching?)
Thank you very much.
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Sputtering with nominally inert gases enhances anisotropic etching, i.e. you etch more into the direction of your plasma power supply. The NX3 gases or also H2 will also etch to some extent give you a reactive etching component which may also attack in other directions thus creating e.g. pits depending on the crystal orientation.
So, if you use Ar for plasma stabilization, you will have to recalibrate your etching rates and may eventually get a different surface finish.
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Magnetohydrodynamic generators are normally used as eihter an attachment to recycle wasted heat and flow of other generators, or used to absorb the energy from rocket thrusters.
However, I'm trying to understand why not use the MHD's as the primary source for power generation while using configurations such as a Tokamak or a Stellarator to confine its combustion and plasma?
Either using the combustion of fossil fuels or the combustion of liquid oxygen/hydrogen rockets, it could be interesting to use it as a compact generator that directly converts electricity from the reaction.
Regardless of what I believe it could be interesting, the specialists on the subject do not use MHD generators in such a way. And I assume there is a good reason for that (such as its low efficiency), which I'm trying to understand.
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In case of burning fossil fuels in an MHD generator leads to plasmas with comparatively low ionisation, which makes such a generator less efficient (you need a good electrical current for such a generator to work properly). Furthermore, an ordinary turbine is much more cost effective for heated gases.
In the case of stellarators/tokamaks you want to have a good confinement of the plasma over a long time (as long as possible). However, if you use your hot plasma specifically as a kind of gaseous conductor to drive a large current through a magnetic field but this breaks the confinement and your fusion rates will go down drastically (or stop entirely).
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.....
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Specifically in the Drude model the two terms are synonyms, meaning they are the same.
In general, a resonance frequency needs to fulfill the resonance condition, while the plasma frequency arises by just by movement of the electrons/ions. There is no intrinsic need for satisfying the resonance condition in this case.
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The CCP type has a structure where plasma is formed at the top and only radicals come down through an ion filter.
I'm curious that even if ions come down, there is no bias applied to the susceptor, because then there is no force to accelerate the ions.
Even if the ion filter doesn't work, wouldn't it cause damage?
Thank you
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In a capacitively coupled plasma (CCP) system, plasma formation at the top and the subsequent movement of radicals through an ion filter is a characteristic feature. The ion filter’s role is to selectively allow radicals to pass while filtering out ions, which could potentially interfere with processes such as chemical vapour deposition (CVD) used for materials like carbon nanotubes (CNTs)1.
The concern about ions potentially causing damage if they were to come down without a bias applied to the susceptor is valid. In typical CCP systems, a bias is not just applied, but it plays a crucial role in controlling and accelerating ions towards the surface. This bias is not just important; it's essential.
However, in the scenario where no bias is applied to the susceptor, the ions would lack the force necessary for acceleration. This could result in a lower energy impact on the substrate, which might not be sufficient for specific processes that require higher ion energies. Nonetheless, even without a bias, ions could still reach the substrate due to diffusion or other electric fields in the system3.
If the ion filter fails to function correctly, the potential risk of uncontrolled ion bombardment on the substrate becomes a significant concern. This could lead to severe damage or undesired modifications of the material properties, which must be avoided at all costs. The extent of the damage would depend on the ion energy, flux, and the nature of the substrate material. It is therefore crucial1.
In summary, while the absence of a bias on the susceptor in a CCP system may not necessarily cause immediate damage, it could compromise the control over the ion energy and, consequently, the quality of the processed material. Proper functioning of the ion filter is critical to prevent potential damage from uncontrolled ion bombardment.
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How these waves form in such a superthermal plasma environment
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Prof. Ran Guo;
I have gone through your research articles. These articles will be very helpful to proceed with my work. Thanks for the recommendation. I will be in touch with you for any further queries.
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I would like to implement a endogenous RNA-based internal amplification control for a RT-qPCR assay used to detect viral pathogens in human plasma samples. Are there any detectable endogenous RNA in human plasma? Any piece of advice ? Thank you!
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Hello Luciana
Some Plasma miRNAs show stability and they are considered as internal control such as hsa-miR-24, hsa-miR-484, hsa-miR-93-5p, hsa-miR-191-5p, hsa-miR-126-3p, hsa-miR-16-5p.
Best regards
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I was wondering if the plasma that is in the top layer after centrifugation can be used to assess proteins, metabolites, hormones, or other molecules, or if the ingredients of the Ficoll alter the measurements. I have not seen any paper regarding this topic or people describing that used the plasma from this technique.
I am particularly interested in zonulin and cytokines.
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Thank you
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How much energy is needed to form plasma, and is a vacuum necessary for plasma formation?
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In addition to Emad Alashkar 's serious answer, a bit into the fun fact range:
vacuum is not needed for having a plasma, you just need brutal conditions such as the gravity field of a star or Randall Munroe's relativistic baseball:
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In cancer biomarker identification most of the studies uses serum, EVs, or plasma as as source of miRNA isolation and identification. Why whole blood is not used as a source? Whole blood miRNA profiles have more potential to show systemic changes as compare to plasma which has lower EV or circulating miRNA concentration. What is the probable reason for this discrimination for whole blood? how will it affect any clinical translational product scientifically?
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Plasma is commonly used for miRNA (microRNA) identification as biomarkers due to several advantageous properties and characteristics: such as Non-Invasive Collection, Stability, reflection of Disease States, Circulating Nature, Quantifiable and Reproducible, Specificity and Sensitivity, Potential for Early Detection
Given these advantages, plasma serves as an excellent medium for miRNA biomarker discovery and application in clinical diagnostics and prognostics.
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I’m looking into bonding a PDMS microfluidic circuit to a PI sheet using a plasma activation method. The PDMS will be on the order of ~700 um thickness, while the PI will be 12.5-50 um. I have read a paper on nitrogen plasma bonding of the two but in their case, they spin-coated the PI onto PDMS. Does anyone know if it’s possible to use such a method on two separate solids? Or preferably even an oxygen plasma bond method?
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Siilanol abd alkocy-cure silicones can br bound to Caption using (chloromethyl)phenylsilane. If temperature is not criitical (chloromethtly)penethylsines can e used. see the arched article, p16 which depicts caption.
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Hi,
I'm doing a test to assess the hemolysis of some plasma samples and I have seen that one of the best methods is to see the absorbance at 414nm using Nanodrop (reference: ).
I tried using the Nanodrop 2000 and the Nanodrop One, but the results are really different, for example, in the first sample in Nanodrop 2000 I obtain a value of 0.075AU and in the Nanodrop One a value of 1.75AU, and this is the same for all of the samples.
Someone knows the difference between how the Absorbance Units are calculated in both cases?
Thanks in advance,
Lluc
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Hello! Please let me know if you ever found out why you got different results. Currently having the same issue.
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How does the choice between albumin and donor plasma as replacement fluids impact the effectiveness of TPE?
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I have simulated an argon plasma in a coaxial structure by COMSOL. To do this, I have used two interfaces, Plasma and Laminar flow, but in the period I have studied (microsecond), the shape of the flame does not appear at the outlet of the tube, and plasma is formed inside the structure.
When I simulated the movement of the fluid in the tube, the fluid formed its own jet-like profile in 3 milliseconds however the plasma formation occurred at 0.4 microseconds.
1. Can fluid at the plasma interface be defined as flowing from the beginning?
2. What other steps are needed to link these two interfaces?
please guide me. thanks...
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I meet the similar problem, did you found the solution?
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What is the difference between the ways of the generation of thermal plasma and non-thermal plasma?In other words,if we generate plasma by a certain method or reactor,how can we determine what kind of plasma it is (NTP or TP)?
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In both thermal and non-thermal plasma the energy is added by an electromagnetic field that accelerates and thus heats up the electrons. In non thermal plasma the heat transfer from the electrons to the atoms and ions is weak so that the later remain relatively cold. In thermal plasma the heat transfer to the atoms and ions is high so that they are at the same temperature which is often around 10 000 K. Most thermal plasma are around atmospheric pressure while non thermal plasma often use reduced pressure. At reduced pressure the collision frequency is lower and thus the heat transfer from electrons to atoms and ions.
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I stored blood sample at -88 five months ago, I would like to ask if there is possibility to thaw them again for isolation of exosomes?
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We regularly used frozen seminal plasma for EV isolation.
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Dear colleagues,
I require urgent assistance regarding the authenticity of the "Plasma Science and Technology" journal. Upon investigation, I found two websites bearing the same name and ISSN number "ISSN: 1009-0630":
  1. https://iopscience.iop.org/journal/1009-0630
  2. https://dlztkxyjs-e.cn/index.php/pst/index
This discovery raises concerns about the legitimacy of one of these platforms. I seek your expertise in discerning the genuine journal from any potential fraudulent counterpart.
Your prompt assistance in clarifying this matter is greatly appreciated.
Warm regards,
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Dear Lina Naji
I raised this/your point here on RG https://www.researchgate.net/post/New_very_misleading_type_of_scam_Anyone_with_recent_examples and mentioned and I quote:
“Thanks to a highly valued member of RG, I came across another example of a hijacked version of a legit and genuine journal called “Plasma Science and Technology”. There are two legit websites of the two (co-)publishers behind this journal:
And
http://pst.hfcas.ac.cn (see also enclosed file how proper papers published by them look like).
There are numerous red flags:
-Looking at the latest volume 25 number 1, I see that basically all papers have nothing to do with the scope of the journal http://dlztkxyjs-e.cn/index.php/pst/index
-Looking at the contact info of this fake journal it is vague, and they make use of Gmail http://dlztkxyjs-e.cn/index.php/pst/about/contact
-The papers published by this fake version are not edited that well, it looks extremely basic. They pretend to be open access while the real one is subscription-based
So, unbelievable but this fake version is a blunt example of a hijacked version of a legit and genuine journal."
Best regards.
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The inquiry relates to a study conducted by Alkouri, Rana, et al. in which they investigated the stability of various biochemical analytes in whole blood and plasma samples stored for different durations before and after centrifugation. Twenty-four analytes were measured in plasma samples, showing variations in concentrations over time.
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During a 6-hour storage period, the stability of routine biochemical analytes in whole blood and plasma from lithium heparin gel tubes was investigated. Results showed that in tubes stored before centrifugation, plasma concentrations of phosphorus and lactate dehydrogenase significantly decreased after 3 hours, while potassium slightly decreased after 6 hours. In plasma stored after centrifugation, bicarbonates decreased after 6 hours, and lactate dehydrogenase moderately increased after 4 hours. According to the reference change value (RCV), all analytes remained stable up to 6 hours, both before and after centrifugation. This study suggests acceptable delays for most biochemical tests on lithium heparin gel tubes in hospital laboratories.
Reference:
Monneret, D., Godmer, A., Le Guen, R., Bravetti, C., Emeraud, C., Marteau, A., Alkouri, R., Mestari, F., Dever, S., Imbert-Bismut, F., & Bonnefont-Rousselot, D. (2016). Stability of Routine Biochemical Analytes in Whole Blood and Plasma From Lithium Heparin Gel Tubes During 6-hr Storage. Journal of clinical laboratory analysis, 30(5), 602–609. https://doi.org/10.1002/jcla.21909
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This inquiry pertains to the study of Neuwinger, Nick et al. entitled "Underfilling of vacuum blood collection tubes results in elevated lactate dehydrogenase activity in serum and heparin plasma samples." I would like to know the effects of volume variation in blood samples on the accuracy of total cholesterol measurements in serum and heparin plasma samples.
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A number of things, including thawed samples, cracked vials, improperly sealed vials, empty vials, and severe hemolysis, can lead to unsatisfactory specimens. Inadequate specimens are recorded on the transmittal using the sample condition codes when they happen infrequently.
Reference. Kwiterovich, Peter. Laboratory Procedure Manual of Total Choloesterol.
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In the laboratory, blood samples are often used to test for LDH. However, I want to know which sample is better as they are both blood samples.
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According to Farhana and Lappin (2023), serum is typically considered a superior sample to plasma for lactate dehydrogenase (LDH) testing. This preference comes from the fact that serum, which is acquired by letting blood clot and then extracting the clot, lessens the possibility of interference from cells generating LDH during processing samples. On the other hand, hemolysis can occur in anticoagulant-collected plasma, leading to erroneously high LDH values. The serum reduces errors related to cell breakdown, hence ensuring a more accurate and consistent assessment of LDH activity.
Farhana, A., & Lappin, S. L. (2023, May 1). Biochemistry, lactate dehydrogenase. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK557536/
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The transition from gel separatory serum tubes to lithium heparin gel tubes in the clinical laboratory.
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The study's findings should be taken tentatively. The results are from one research period alone, which only lasted two years (2022, 2023) and only had 76 participants, whose medical conditions were also not stated. There were a number of studies in the past referenced however, performing the same question of plasma as an alternative to serum, to which the results did align. But even so, this transition to using plasma instead of serum has not been normalized for a reason: and that is due to the long standing tradition of serum being used, and a reluctance of abandoning that tradition.
In the same vein, for lithium heparin in particular, the study's findings show consistency and high quality results with plasma.
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The entire point of Oguzhan Zengi's study was to improve turnaround time and sample quality by exploring the less traditional option of plasma for the above reasons. The results did not suggest an outright replacement of serum, but showed many positives and reasoning for such.
In a way, one might say plasma has been neglected. This begs the question: what other potential sample variations could be used to improve TAT and sample quality?
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Beyond plasma and serum, several other sample variations could be explored to improve turnaround time (TAT) and sample quality in clinical or research settings. Here are a few possibilities:
1. Urine: Urine samples are readily obtainable and contain valuable diagnostic information. Further exploration could lead to quicker and more effective testing methods for a range of conditions.
2. Saliva: Saliva samples are easily accessible and offer diverse biomarkers for diagnostics. Enhancing our understanding and handling of saliva could streamline testing processes, improving accuracy and efficiency.
3. CSF: CSF samples hold critical insights into neurological conditions. Advancements in CSF sample processing and analysis techniques could enhance diagnostic speed and reliability for brain-related issues.
4. Stool: Stool samples provide significant insights into gastrointestinal health. Research into improved handling and analysis methods could optimize diagnostic accuracy and turnaround time for gut-related conditions.
5. Sweat: Sweat contains diagnostic markers for various conditions. Investigating enhanced methods for sweat sample collection and analysis may expedite and refine diagnostic processes.
6. Tissue: Tissue samples play a crucial role in diagnosing organ-specific diseases. Refining techniques for tissue sample processing and analysis could lead to swifter and more precise disease diagnosis.
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This question is derived from an article entitled "Underfilling of vacuum blood collection tubes leads to increased lactate dehydrogenase activity in serum and heparin plasma samples" by Neuwinger et. al. in 2019. I want to know how certain anticoagulants affect the lactate dehydrogenase activity in plasma or serum samples.
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The preservation of enzyme activity is the main connection between the anticoagulants used in blood collection tubes and the lactate dehydrogenase (LDH) activity in plasma or serum samples. Cells contain an enzyme called LDH, whose activity can be evaluated in serum or plasma samples to determine whether a disease or tissue damage has occurred.
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The research "The transition from gel separatory serum tubes to lithium heparin gel tubes in the clinical laboratory" is a study that aims to assess the viability of replacing serum samples with plasma samples in various clinical chemistry and immunoassay tests and to examine the implications of turnaround time (TAT) and sample quality during the transition process and a result of the study shows that there is a decreased TAT.
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There are previous studies that show the same result to the TAT. Some studies such as the study of Hetu et al. and Ramakers et al. For Hetu et al.it studied Potassium test and concluded a significant decrease in the average time in terms of sample reception and result confirmation. This is similar to Ramakers et al. wherein there is a decreased median TAT with the use of Barricor tubes. Another study is from Badiou et al. that reported the same result using Barricor tubes instead of gel LIH tubes. In this study, the TAT was reduced due to the use of plasma instead of serum that needs to be clotted which is the factor that increases the TAT.
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Oguzhan Zengi's study on the switch from gel-separator serum tubes to gel-separator lithium heparinized plasma (LIH) tubes in clinical chemistry was critically analyzed, leading to the formulation of this research question. According to the journal of Oguzhan Zenki, "The Transition from Gel Separatory Tubes to Lithium Heparin Gel Tubes in the Clinical Laboratory," there was a random selection of sample sources at the emergency department. Hence, this gave birth to the question concerning the result's accuracy.
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It is worth mentioning that the samples collected from the emergency department could potentially result in inaccurate findings due to the randomization of patients coming from the emergency department. This may lead to a biased sample, which could affect the validity of the results. In order to overcome this, one possible solution is to standardize the patients coming from the emergency department. For example, we could only collect samples from patients who have been involved in car accidents. This approach would help ensure that we obtain a representative sample and minimize the potential for bias, which will lead to more accurate and reliable results.
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According to the study "The transition from gel separatory serum tubes to lithium heparin gel tubes in the clinical laboratory", most clinical chemistry and immunoassay tests can be performed using lithium heparinized plasma (LIH) tubes instead of serum tubes, except for the lactate dehydrogenase (LDH) test. Lithium heparinized plasma (LIH) tubes have been shown to enhance healthcare quality, improve sample quality, reduce the incidence of aspiration errors, and lessen laboratory staff workloads in clinical settings. However, the reason why the LDH test cannot be performed in most immunoassay and clinical chemistry procedures that use lithium heparinized plasma (LIH) tubes is still unclear.
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Since lithium heparin interferes with the lactate dehydrogenase (LDH) test, most clinical chemistry and immunoassay assays cannot be performed using lithium heparinized plasma (LIH) tubes. An anticoagulant that is frequently used in blood collection tubes to stop clotting is lithium heparin. It may, however, obstruct several colorimetric and enzymatic tests, such as the LDH test. Red blood cells, the heart, liver, muscles, kidneys, and other tissues all contain the enzyme LDH. It is essential to cellular metabolism because it helps in glycolysis by changing lactate to pyruvate. Increased blood levels of LDH may be a sign of illness or tissue injury. Lithium heparin can cause interference with the enzymatic reaction or the assay's detection technique, which can lead to false increases or decreases in LDH activity. Inaccurate results from this interference may have an impact on patient diagnosis and therapy.
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This question aims to understand the rationale behind the study, which likely sought to evaluate the comparability of gel separator serum and LIH plasma tubes in clinical chemistry and immunoassay tests. Additionally, it seeks insights into the study's findings concerning sample quality and turnaround time during the transition from serum to plasma samples, shedding light on the efficiency and reliability of different tube types in laboratory procedures.
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Most tests showed no significant difference between the serum and LIH tubes. For some analytes, total error (TE) values exceeded the total allowable error (TEa) limits. Insulin TE value did not exceed TEa but consumed nearly all its error budget. Plasma tubes could be used instead of serum tubes for most tests, except for lactate dehydrogenase (LDH). Plasma tubes improved sample quality, reduced the incidence of aspiration errors, and decreased TAT in the emergency laboratory.
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We are trying to sputter a metallic target. We can clearly see the plasma however after depositing for more than 30 minutes there is no deposition on the substrate. What can be the reason for this? need expert advice.
Thanks!
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I think that the gas pressure is a critical factor. Increasing the gas pressure will raise the collision frequency and the sputtering rate, but it will reduce the average mean free path of the sputtered atoms to reach the substrate and will also reduce the adhesion.
So, it is better to control the gas pressure in low range to have better adhesion and allow a longer mean free path of the sputtered atoms reaching the substrate.
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I want to understand what the Warburg effect is and how it affects LDH activity in cancer.
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The Warburg Effect characterizes the metabolic shift in cancer cells, prioritizing increased glucose uptake and lactate fermentation despite functional mitochondria, to fuel growth and survival (Liberti et. al., 2016). Glucose metabolism generates ATP crucial for cellular energy needs and yields lactate or CO2 as end products depending on full mitochondrial oxidation or fermentation. Lactate dehydrogenase (LDH) catalyzes the conversion of pyruvate to lactate, regenerating NADH to NAD+ (Alegre et al., 2015). Moreover, in tumors, increased glucose uptake leads to elevated lactate production. In conclusion, the Warburg Effect does not directly increase LDH levels, instead, LDH activity is central to the metabolic rewiring observed in cancer cells undergoing the Warburg Effect resulting in increased levels of LDH in serum and plasma.
References:
Liberti MV, Locasale JW. The Warburg Effect: How Does it Benefit Cancer Cells? Trends Biochem Sci. 2016 Mar;41(3):211-218. doi: 10.1016/j.tibs.2015.12.001. Epub 2016 Jan 5. Erratum in: Trends Biochem Sci. 2016 Mar;41(3):287. Erratum in: Trends Biochem Sci. 2016 Mar;41(3):287. PMID: 26778478; PMCID: PMC4783224.
Alegre, E., Sammamed, M., Fernández-Landázuri, S., Zubiri, L., & González, Á. (2015). Circulating biomarkers in malignant melanoma. In Advances in clinical chemistry (pp. 47–89). https://doi.org/10.1016/bs.acc.2014.12.002
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I would like to ask about the thrust in PPT (Pulsed Plasma Thrusters) which uses solid propellants such as Teflon.
We know that the thrust force is given as F= T= d(m ve)/dt = m dve/dt + ve dm/dt. We know that both the mass and also the exhaust velocity ‘ve’ are not constant, the velocity usually fairly similar to the trend of the discharge current signal.
The question is:
Why the most (or ALL) of researches consider that the exhaust velocity 've' as constant value and neglect the second term of the equation? Is because the experimental measurements do not allow detecting the variation or something else?
Secondly,
If so, How about the theoretical calculations? Should we consider the variation of ‘ve’ or just take the constant value? and which one? is it the peak or the average velocity on the exit muzzle? average of peak velocity along the discharge tube?
Also, How about the specific impulse ‘Isp’ in both cases? Is it just as Isp = T/(g*m_dot) or ve/g and which ve?
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For a propulsion device, the thrust it generates comes from the mass and velocity of the particle ejected from the nozzle (or electrode), where this velocity should be that of the particle at the moment it flies out of the nozzle (or electrode).
In a PPT, the arc ablates the solid propellant to produce neutral gas, part of which is ionised into plasma and accelerated by the electromagnetic force then ejected out of the electrode to produce thrust. Therefore, there are many types of charged and neutral particles produced by a single discharge of PPT using PTFE as propellant.
In general, the impulse generated by a single discharge of a PPT can be classified as neutral gas-generated or plasma-generated. However, in experiments, it is difficult to obtain the amount of plasma produced by a single discharge, and the velocities of different components and clusters in the plasma are also different. So, as you say, dm in the equation 1 is hard to measure by experiment.
In addition, since the plasma velocity (generally more than 20km/s) is much more higher than the neutral gas velocity (about 5km/s), it is generally assumed in the calculations that the entire source of thrust is from the plasma and the contribution of the neutral gas is ignored, but this assumption can only be used if the PPT is electromagnetic type rather than electrothermal type.
I hope my answer is useful to you.
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I am planning to get some blood from patients to perform RNA seq (circular RNA which requires deep sequencing). I am wondering if anyone can share the protocol with details. I am also wondering about the amount of blood (whole / plasma / serum) to isolate RNA for deep sequencing. Thank you so much for your help!
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You can use EasyPure® Genomic DNA Kit, 200ul from clotted blood is enough to start your protocol then follow the pamphlet protocol
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How many ug/particles of EVs is needed for doing proteomics?
We are doing many steps for purify EVs of human plasma and at the end of the process we are getting just 1/2ug/ml concentration of EVs, which is about 2.17e+10 / 8.18e+09 particles/ml. What is the volume or minimal ug for doing proteomics?
Thank you!
Linoy.
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What factors or physical mechanism will affect the laser produced plasma (LPP) expansion process. How to reduce the instability of multiple measurements?
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The instability in the process of laser plasma expansion arises from a multitude of factors that influence the dynamics of the expanding plasma. Hydrodynamic instabilities, including Rayleigh-Taylor and Richtmyer-Meshkov instabilities, emerge at the interface between the laser-produced plasma and the surrounding medium, leading to mixing and irregularities in plasma expansion.
Additionally, self-focusing effects can occur due to the nonlinear response of the plasma to intense laser fields, resulting in filamentation or channeling within the plasma. Nonuniform heating, whether from variations in laser intensity or material properties, can cause uneven expansion velocities and density gradients, triggering further instability. Collisional effects and the presence of magnetic fields also contribute to complex plasma dynamics, altering expansion behavior and stability. Radiative cooling further complicates matters, as it affects energy balance and can lead to fragmentation or condensation of the plasma. Moreover, pulse-to-pulse variations in laser parameters or target conditions introduce stochastic fluctuations, exacerbating instability.
Understanding and mitigating these instabilities are vital for applications such as laser fusion and plasma-based accelerators, necessitating a combination of theoretical modeling, numerical simulations, and experimental diagnostics.
Resources such as scientific journals like "Physics of Plasmas," "Journal of Applied Physics," and "Physical Review Letters" provide valuable research articles on laser plasma dynamics and instability mechanisms, while textbooks like "Fundamentals of Plasma Physics" by J.A. Bittencourt offer comprehensive insights into plasma behavior and instabilities. Additionally, research groups and laboratories specializing in laser plasma interactions, such as the Lawrence Livermore National Laboratory's National Ignition Facility (NIF) or the Max Planck Institute for Plasma Physics, conduct experimental studies and provide valuable data for understanding and addressing plasma instability challenges.
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.nonionic liquid
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Hey there Ghazal Tuhmaz!
Alright, let's dive into why we're all about using nonionic liquids in the wire explosion plasma method for creating metal nanoparticles.
First off, nonionic liquids bring some serious perks to the table. They're like the cool, calm, and collected sidekick in this explosive process. Unlike their ionic counterparts, nonionic liquids don't carry an electric charge. This means they play nice with metals during the explosion phase without causing any unwanted reactions or disruptions.
Now, onto the wire explosion plasma method. Picture this: we're zapping a thin metal wire with a super high-voltage pulse of electricity. This sends shockwaves through the wire, causing it to literally explode into tiny droplets.
Here's where the nonionic liquid swoops in like a superhero. It acts as a stabilizer, surrounding those newly formed metal droplets and preventing them from clumping together like unruly magnets. This helps us maintain control over the size and distribution of our precious metal nanoparticles.
In essence, nonionic liquids are the unsung heroes of the wire explosion plasma method. They keep the chaos in check and ensure we walk away with beautifully dispersed metal nanoparticles ready to work their magic in various applications.
Hope that sheds some light on why we're all aboard the nonionic liquid train for this explosive endeavor! If you've got more questions or need further elaboration, don't hesitate to give me a shout. Cheers Ghazal Tuhmaz!
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Hi,
I have to extract genomic DNA from plasma samples and will use the Qiamp DNA mini and blood kit (QIAGEN). At the moment the plasma samples are stored at -80° and they were obtained from whole blood using a single centrifuge 1800 rpm x 10min. I would like to know whether it is appropriate to centrifuge the sample (and thus concentrate the remaining cells into a pellet) before proceeding with the addition of proteinase K, and if so, how should the centrifugation be performed?
Thanks!
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Hi Federica,
Freezing likely lysed most of the cells, so centrifugation would make little to no difference.
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What is the most efficient time to oxygen plasma of PDMS to increase the hydrophilicity?
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Thank you for your information.
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The subject of the study centers on the switch from gel separatory tubes to lithium heparin gel tubes in the clinical laboratory but the study additionally addressed the use of the Barricor mechanical separator heparinized plasma tube that was acknowledged by Hetu et al.
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The research "The transition from gel separatory serum tubes to lithium heparin gel tubes in the clinical chemistry" claims that during centrifugation, LDH may be released from platelets and other cells into plasma. This is because the Barricor mechanical separator heparinized plasma tube provides high-quality plasma sample for chemistry determinations for in vitro diagnostic use, thanks to its current mechanical separator that is being launched under centrifugation.
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I am trying to detect CCK in plasma with the antibody. if anyone knows how to detect and how much to load.
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In plasma due to the presence of too many proteins (with albumin constituting nearly half of it), it would be difficult to detect CCK, especially if it has a low expression. Moreover, you are likely to get high background due to the presence of other proteins.
I would recommend the use of Immunoprecipitation method, a method that enables the purification of your protein of interest. An antibody for target protein is incubated with plasma enabling the antibody to bind to the protein in solution. The antibody/antigen complex is then pulled out of the sample using protein A/G-coupled agarose beads. This isolates the protein of interest from the rest of the sample. The sample can then be separated by SDS-PAGE for western blot analysis.
The Immunoprecipitation protocol is provided in the link below.
Best.
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why plasma plume turn to be longer at a lower pressure? Is that attribute to pressure?
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Dear Jian,
Yes, It is due to the outside pressure. As the pressure is decreased, the plasma plume expands both in length and width. These expansions are stretched and built up farther from the nozzle exit. The primary reason for this expansion is the decrease in absolute pressure. As the number of surrounding molecules decreases, their collision with the species exiting the nozzle also decreases. As a result, the jet requires more distance to equilibrate pressure. When both the exit and outside pressures are equal, the jet's static pressure is in equilibrium with the surrounding pressure, and no expansions occur.
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can FBA be substitute of plasma
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Without more info, not sure why you would need either. What is your nutrient medium?
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I would like to know why an FFHR's plasma has no need for high power amplification performance.
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Because the idea is to have a fusion reactor that produces neutrons but can be shut down at any time, this means that the fusion reactor in a fusion-fission scheme doesn't need to reach break-even (actually, it even should not reach it). Thus, you don't have to get the plasma so well-confined that it burns on its own.
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The research titled "The transition from gel separatory serum tubes to lithium heparin gel tubes in the clinical laboratory" is focused on estimating the potential of replacing serum samples with plasma samples in various Clinical Chemistry and Immunoassay tests. According to Zengi (2023), plasma is gradually gaining popularity over serum due to the advantages it provides. It has several advantages, including greater volume, no need to clot prior to centrifugation, and improved sample quality. However, it is not clear as to why plasma has a larger volume compared to serum regardless of having the same volume of blood drawn.
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The difference in volume between plasma and serum, despite the same volume of blood being drawn, can be attributed to the presence of clotting factors in plasma. Plasma contains clotting factors, such as fibrinogen, which contribute to its larger volume compared to serum. When blood is collected and allowed to clot, these clotting factors form a fibrin mesh, trapping cellular components and causing the serum to occupy a smaller volume relative to plasma. Therefore, even though the same volume of blood is drawn, the absence of clotting factors in serum results in a smaller volume compared to plasma.
The difference in volume between plasma and serum, despite the same volume of blood being drawn, can be attributed to the presence of clotting factors in plasma. Plasma contains clotting factors, such as fibrinogen, which contribute to its larger volume compared to serum. When blood is collected and allowed to clot, these clotting factors form a fibrin mesh, trapping cellular components and causing the serum to occupy a smaller volume relative to plasma. Therefore, even though the same volume of blood is drawn, the absence of clotting factors in serum results in a smaller volume compared to plasma.
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Gel separator serum tubes and gel separator lithium heparinized plasma tubes are commonly used in clinical laboratory practices for sample collection and processing. The choice between these tube types can have implications for various aspects of laboratory operations. Understanding the factors influencing the choice between these tube types is essential for optimizing laboratory workflows and ensuring reliable diagnostic testing.
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The research aimed to identify the factors influencing the choice between gel separator serum tubes and gel separator lithium heparinized plasma tubes in clinical laboratory practices. Through an analysis of laboratory processes, sample quality indicators, and turnaround time (TAT) data, the study investigated variables such as test accuracy, sample stability, clotting time, ease of processing, and impact on TAT. Additionally, factors such as cost-effectiveness, availability of tubes, and adherence to quality control standards were examined. The findings of the study shed light on the considerations guiding the selection of tube types in clinical laboratories, providing insights for optimizing laboratory workflows and ensuring accurate and efficient diagnostic testing
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The development of this research question arises from a critical review of the study conducted by Oguzhan Zengi on the transition from gel separator serum tubes to gel separator lithium heparinized plasma (LIH) tubes in clinical chemistry. Hence, it emerges from a desire to delve deeper into the practical implications of adopting LIH tubes in clinical chemistry practices.
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The study aims to assess the viability of replacing serum samples with plasma samples in clinical chemistry and immunoassay tests, examining the implications on turnaround time (TAT) and sample quality during the transition process. Results demonstrate that while most tests showed no significant difference between serum and LIH tubes, some analytes exceeded total error (TE) values derived from total allowable error (TEa) limits. However, alternative allowable error limits were determined for certain tests, indicating that plasma tubes could be used instead of serum tubes for most tests, except for lactate dehydrogenase (LDH). Additionally, the use of plasma tubes improved sample quality, reduced aspiration errors, and significantly decreased TAT, thus suggesting that LIH tubes can effectively replace serum tubes in clinical laboratories, enhancing healthcare quality and reducing staff workload.
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For my tantalum pentoxide thin film integrated capacitors, I need to etch the tantalum and tantalum pentoxide layers with pure SF6 plasma. While etching these layers copper will also be exposed to the plasma. Does anyone know if the copper will be etched too (and if so at which etch rates) and if it reacts in a form so that the copper will no longer be conducting?
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When etching tantalum and tantalum pentoxide layers with pure SF6 plasma, copper will also be exposed to the plasma. Copper is known to be etched by SF6 plasma, but the etch rate depends on various factors, such as plasma power, pressure, and gas flow rate. The etch rate of copper in SF6 plasma can range from 0.1 to 1.5 μm/min.
Copper can react with SF6 plasma to form copper fluoride (CuF2) and copper sulfide (CuS). Copper fluoride is an insulator and can prevent copper from conducting electricity. However, the formation of copper fluoride can be suppressed by adding oxygen to the SF6 plasma.
It is important to note that the etch rate of copper in SF6 plasma is much slower than that of tantalum and tantalum pentoxide. Therefore, it is possible to selectively etch tantalum and tantalum pentoxide without significantly etching copper by optimizing the etch conditions.
More at:
CP2014_Filipovic_5.pdf (tuwien.ac.at)
Use of Copper Mask in SF6/O2 Chemistry in PT-MTL | Stanford Nanofabrication Facility
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If electron temperature and electron excitation temperatures in plasmas are different, then, is there any case they will be equal or always remain unequal?
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Please read the following publications dealing with the subject in detail:
1. Pure Appl. Chem., (2013) 85(12), 2231–2248
'Departure from local thermal equilibrium during
ICP-AES and FAES: Characterization in terms of
collisional radiative recombination activation energy'
Mark F. Zaranyikam, Courtie Mahamadi
2. Spectrochim. Acta, Part B 37, 987 (1982)
'Evaluation eines Elektronendiffusionsmodelles zur Berechnung
von nicht Gleichgewichts-Elektronenkonzentrationen im Induktiv
gekoppelten Argonplasma fiir die spektrochemische Analyse'
F. Aeschbach
In plasmas the electron temperature is always much different from the temperature based on the mean kinetic energy of atoms , ions and small molecules.
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Many thanks in advance.
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Many thanks for your answer. Amakiri Friday Okilo
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difference between excitation temperature and electron temperature in plasma
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I would quibble that "excitation temperature" is not a thing--excitation *energy*, however, is a thing. Electron temperature is the average energy of the electrons in a plasma; excitation energy is the energy for an electron to attain an excited state. If the electron temperature is approximately equal to the excitation energy, then statistically there will be many excited electrons, so one might loosely (and incorrectly) refer to the plasma being at the excitation temperature. Do not use that terminology, but if someone ignorant does use it, that's my guess what they mean.
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what is excitation temperature of electron in plasma
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The typical temperature of the electrons used to excite atoms or ions in a plasma is known as the excitation temperature. It characterizes the electron population in terms of thermal equilibrium and explains the distribution of electron energy. When doing spectroscopy or researching emission or absorption lines in a plasma, the excitation temperature is very important. Nevertheless, a single excitation temperature may not be sufficient in non-equilibrium plasmas, requiring a more thorough examination of energy distribution functions.
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I am currently engaged in the analysis of a collection of previously obtained samples, which primarily comprise frozen whole blood. My specific requirement pertains to isolating the plasma component from the aforementioned samples.
However, upon thawing, I have observed a phenomenon wherein the red blood cells (RBC) appear to have undergone lysis. Consequently, I am encountering challenges in effectively separating the plasma from the cellular constituents of the blood. Despite employing the Ficoll-paque gradient method, my endeavors have been met with limited success.
I would greatly appreciate any suggestions or guidance you may have in overcoming this issue.
Thanks!
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I think that this is impossible because the fluids are mixed. But if you measure specific components like some plasma proteins or Calcium (this is not present in red cells, if I remember correctly) you may possibly correct the concentrations using the hematocrit value if known or hemoglobin concentration (usually 330 g/l in red cells).
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Our process involves generating plasma with Ar and Hydrogen gases, followed by the deposition of Hydrogenated Carbon.
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Again here is Jürgen Weippert with his dum chatboat. A lot of words, no help.
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Oral 2mg diazepam, half-life 20 h, bioavailability 90%, what is the concentration in saliva after 14 h?
knowing that the saliva drug concentration is 0.1 of the plasma concentration.
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The initial distribution phase has a half-life of approximately 1 hour, although it may range up to >3 hours. (...) The initial distribution phase is followed by a prolonged terminal elimination phase (half-life up to 48 hours). The terminal elimination half-life of the active metabolite N-desmethyldiazepam is up to 100 hours. (...) Elimination half-life increases by approximately 1 hour for each year of age beginning with a half-life of 20 hours at 20 years of age.
As you know situation is quite dynamic and complicated ....
Tmax = 1.25h + initial elimination half-life =1h next phase half life= 3h and elimination/terminal =20h (if 20 years old patient).
I think this paper (which covers an oral dose of 5 mg) shows PK profile could be useful.
From my raw estimation 14 h after a single dose of 2 mg per os in saliva it should be around 1 ng/mL but it's not based on an exact analysis of raw data please double-check....
I hope it helps in your investigation ....
Tomasz
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When two intense laser beams interact with a plasma, is second harmonic generation produced?
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Second harmonic generation (SHG) occurs when two laser beams beat in a plasma, producing harmonics. The process is more efficient when the beat frequency is the same as the resonant frequency. When the modulation frequency is twice that of the incident laser beams, the strength of the combined electric field is modulated. The efficiency and circumstances of SHG observation depend on experimental setup, laser properties, and plasma parameters.
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I am determining butyric acid in plasma.
For this, I am developing a method. I will be giving a brief on how I prepare my highest concentrated calibration standard.
I prepare my internal standard (d7- butyric acid) in 100% acetonitrile having a concentration of 100 uM. From which, I transfer 10 uL to a cold glass vial along with 10 uL of 10 mM of Butyric acid as my highest concentrated calibration standard. I use 10 uL of 20% PFFBr in 100% acetonitrile to derivatise my standard and heat it for 1 hour at 60*C.
  • The problem I am facing is low signals of internal standard to an extent that it cannot be even detected within the given retention time.
  • Also, I am receiving signals for butyric acid in my blank and no peak for internal standards.
Could you please help me?
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If you cannot derivatize the short-chain fatty acids, they can accumulate in the inlet/liner/column head, etc due to their low volatility...
Therefore it is very critical to get a satisfactory dervizatization yield...Probably the yield of the derivate was low and free fatty acid along with its deutereted form remained intact and stuck to the sample introducing parts of the GC before chromatographic separation...
To increase the efficiency, increase the reaction time, test the elevated temperatures, and, add more PFFBr and organic solvent to overcome any stochiometry-related issues...At this point, it may be better to choose another aprotic organic solvent as a reaction buffer like hexane, and observe the efficiency in comparison. Investigate if any co-solvent or agent is necessary or not to promote reaction...
Methylation of butyric acid in many cases also works well and would be sufficient for quantification. So, I mean other than PFFBR derivatization there are other ways to do that such as TMS or acid catalysis followed by methanol spiking...
Here is an example;
Samples can be derivatized neatly after dissolving in a solvent. If appropriate, dissolve the sample in a nonpolar solvent (such as hexane, heptane, or toluene). If the sample is in an aqueous solvent, first evaporate to dryness then use neat or dissolved in an organic, non-polar solvent.
Weigh 1-25 mg of sample into a 5-10 mL micro reaction vessel.
Add 2 mL BCl3-methanol, 12% w/w. A water scavenger (such as 2,2-dimethoxypropane) can be added at this point.
Heat at 60 °C for 5-10 minutes. Derivatization times may vary, depending on the specific compound(s) being derivatized.
Cool, then add 1 mL water and 1 mL hexane.
Shake the reaction vessel (it is critical to get the esters into the non-polar solvent).
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Hi, everyone!
I am a graduate student of pharmacology from China. I am trying to measure the plasma NETs level with anti-MPO antibody and Sytox Green, which are available in our lab. Here's how I did it.
Firstly, a high-binding 96-well plate were coated overnight at 4 ℃ with anti-MPO antibody(1 μg/mL, Thermo). The plate was washed 1 time with wash buffer, then blocked with 4% BSA in PBS supplemented with 0.05% Tween-20 for 1.5 hours at room temperature. The plate was washed 3 times again, then incubate with plasm (100 μL) for 2 hours at 37 ℃, 300 rpm. The plate was washed 5 times before incubating for 15 minutes with Sytox Green in dark (100 μL, 1:1000, Thermo). The fluorescence intensity (excitation at 485 nm and emission at 535 nm) was quantified.
But there was no difference in fluorescence intensity between plasma and negative controls. I'm not sure what went wrong. I hope anybody who did it can give me some advice. Thank you so much for your generous help!
Best wished!
Yafei, Fang
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There may be two explanations for this:
1) The concentration of Sytox green is too high (5mM diluted 1000 times = 5µM, which is a lot for this type of agent). It is preferable to work between 10-100nM to hope to see differences
2) Sytox green is a reagent which sticks to nucleic acid, it is impermeant to live cells. Therefore, this reagent also marks any cellular debris that is found in media, this will mask the differences between your different conditions. Flow cytometry makes it possible to overcome this signal which comes from cellular debris.
Below , please find a link for a paper describing the quantification of NETs by flow cytometry,
Best regards
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when extraction of RNA save the blood with trizol or serum or plasma
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There is a debate over whether serum or plasma is the most appropriate sample type to detect both miRNA and RNA expression. Several studies have found that plasma samples provide a higher recovery of miRNA (based on real-time RT-PCR), although others have seen no or minimal difference between serum and plasma.
I feel serum sample would be more appropriate because additional RNA may be released from cells during the coagulation process. Cell lysis, especially the highly abundant red blood cells, during the coagulation process is one of the possible explanations for the RNA concentration difference between serum and plasma. During the coagulation process, blood cells are exposed to a stressful environment which in turn may stimulate the release of certain miRNAs and RNAs. Additionally, the platelets also contain significant amounts of RNA which might also be released into the serum during the coagulation process.
I have attached a few articles below which you may want to refer.
Best.
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I mixed EDTA mouse plasma with standard gel sample buffer and got very smeary image on Western with no distinct bands. Is there something in the plasma that needs to be removed before I run gels?
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When working with plasma samples for Western blotting, certain components in the plasma can interfere with electrophoresis and contribute to smearing on the gel or affect the separation of proteins. Here are some considerations and steps you can take to improve the resolution of your Western blot:
  1. Remove Lipids:Plasma contains lipids, which can cause smearing on the gel. To remove lipids, you can perform a quick spin or centrifugation step before loading the sample onto the gel. Centrifuging the plasma at a higher speed can pellet lipids, and the supernatant can be collected for further analysis.
  2. Deplete Albumin:Albumin, being a highly abundant protein in plasma, can sometimes dominate the gel and hinder the separation of other proteins. You may consider depleting albumin using methods such as albumin depletion columns or other commercially available kits.
  3. Precipitate Proteins:Precipitating proteins with a compatible reagent or using a protein precipitation method can help remove interfering substances and concentrate your protein of interest.
  4. Use Sample Buffer with Reducing Agent:Ensure that your sample buffer contains a reducing agent (e.g., DTT or β-mercaptoethanol) to break disulfide bonds and denature proteins. This is crucial for obtaining well-defined bands on Western blots.
  5. Properly Prepare the Gel:Make sure your gel is properly prepared and run under appropriate conditions. This includes using the correct percentage gel for the size range of your proteins and running the gel at a suitable voltage.
  6. Optimize Electrophoresis Conditions:Optimize electrophoresis conditions, such as voltage and run time, to achieve the best separation of proteins. Running the gel at a lower voltage for a longer time can sometimes improve resolution.
  7. Verify Protein Loading:Ensure that you are loading the appropriate amount of protein. Overloading can lead to smearing and poor band resolution.
  8. Use a Pre-cast Gel:Consider using pre-cast gels, as they are standardized and can provide better reproducibility.
  9. Check Antibodies and Detection System:Verify the specificity and sensitivity of your antibodies. Ensure that your detection system is optimized for the proteins of interest.
  10. Consider Gel Filtration or Size-Exclusion Chromatography:
  • If needed, you can consider using gel filtration or size-exclusion chromatography to separate proteins based on size before running them on a gel.
By addressing these considerations and optimizing your sample preparation and electrophoresis conditions, you should be able to achieve clearer and more distinct bands on your Western blot.
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I red a paper on an important journal of cardiology. In this work they found that 8 miRNAs were dysregulated in plasma samples of a study cohor of 1710 participants (Controls + patientes affected by Heart failure). I evaluated these 8 miRNAs in plasma samples in a study-cohort of 129 subjects (Controls + Heart failure patients) and I found that only 2 miRNAs were dysregulated according to the work I red. Because I have to explain thi data in "Discussion" I don't know how to explain this difference. Why could be the main reason of these different results? Maybe the size samples or other? Thank you
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The number of participants and their demographics could be a factor. Race and differences in cardiometabolic issues might be influencing the differences miRNA expression. Try look at the DEGs associated with the miRNAs that didn't match up, this will give you more insight into what's happening. It could be technical differences like choice of housekeeping genes, normalization process.
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Are there some references which show measurement results?
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This question is difficult to answer If we talk about single streamers, then the resistance is 500 kOhm for a 10 cm long streamer. Approximately the same resistance has a 5 cm long streamer. If you are interested in this question in more detail, then you can find the answers in our article PROBE MEASUREMENTS OF PARAMETERS OF STREAMERS OF NANOSECOND FREQUENCY CROWN DISCHARGE
Ponizovsky A.Z., Gosteev S.G.
Physics of Atomic Nuclei. 2017. Vol. 80. No. 11. pp. 1704-1710.
If you have any questions, I will be happy to answer them my address sasha_laron@mail.ru Sincerely Alexander Ponizovskiy
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I am running some pulldown experiments using plasma samples(click biotin linker on protein, then blot against Strep-HRP). We started the experiment with a known protein (Lane 2-5) then plasma samples (Lane6-9), lane 5 and 9 both incubated with alkyne-biotin. Although the signal is very small and on WB I need to overexpose to see it, but the bands on lane 9 is giving a bizarre signal. Could anyone help me understand the reason for this and how to solve it?