ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.
Browse by research topic to find out what others in your field are discussing.
- Is there a cell line that expresses membrane-bound CD40L?
I know of the 3T3-mCD40L cell line that expresses a soluble form, but how about a good cell line that expresses CD40L that remains surface bound?
Ideally I would like the ligand immobilised on cells in order to carry out some in vitro biding assays.
Murine L cells, human BrCa cell lines can express membrane-bound CD40L. NIH 3T3 cell line also stably expresses the mouse CD40L. For further details you can refer to the following links:-
2. www.ncbi.nlm.nih.gov › NCBI › Literature › PubMed Central (PMC)Following
- Do you know different methods to determine Hg in fish?
I need to determine Hg in fish
The Atomic Absorption Spectrophotometry (AAS) with cold steam is used to determine mercury in different samples
- Can anyone suggest a paper or journal regarding current state-of-the-art miniaturized droplet-based evaporative cooling systems?
This cooling may be droplet water cooling and also the key energy considerations for evaporative cooling system design. Moreover the most promising areas for technology development in evaporative cooling system can be discussed.
In order to find the articles it is better to search with the keywords in googlescholar or Sciencedirect websites.
Also, if you are looking for a comprehensive state of the art, try to find experts in the topic and then contact them with email. I am almost sure that senior researchers in the field can help you to find whatever you want.
- Could someone please provide information about effect of Zoloft on language development of children with autism?
I particularly want more information on its effects on children below 5y. Thanks.
Thanks for the resources Dora.Following
- What are the methods to find Bronsted and Lewis acid sites of heterogeneous catalysts? In addition to the pyridine FT-IR method are there any other methods that can be applied to measure the Nature of different acid sites such as the Bronsted and Lewis acid sites of a catalyst?
What methodology did you finally choose?Following
- Why does the XRD peak shift when I measure(400) silicon using 2theta scan ?
I measured (400) silicon bulk sample by using k-alpha1 X-ray of Cupper.
For theta/2theta scan, The angle of a peak of (400) silicon is about 70 degree. It obeys Bragg's law.
However for 2theta scan, I've got an angle at 40 degree, not 70 degree.
I am almost sure that the angle is a shifted peak of (400) silicon.
The situation is not obeying Bragg's law, because the incident beam angle cannot be 35( = 70/2) degree when using 2theta scan.
Is this situation really caused by shifting like I mentioned above? If this hypothesis is right, why does the shift occur?
Maykel! You need to post a new question with these potential conclusions. Include details of your experimental setup, sample morphology including estimated film thicknesses and orientations. I'd be very cautious about making such conclusions from a single diffractogram of a potentially monocrystalline or polycrystalline structure. (What is it mono or poly, in your case?) I bet you are using the conventional point counter again :-)
That is still ok but use it cleverly to isolate spatial variations. It is a lot more tedious than using a quick exposure with photographic dental film or better yet a 2D imaging system. But you can do it.Following
- Should I use a case study or phenomenological methodology for my study?
My study is on the perceptions of worker's on their leaders' behavior relative to safety in their respective organizations
I am thinking a case study but wondering if phenomenological methodology would be better.
A case study isn't a way of gathering data as such. It's a research design that focuses on a bounded case rather than a population sample. Within a case study you can use any method but usually you are looking for in-depth data so you could you use a phenomenological approach via semi-structured interviews. Focus groups introduce a group dynamic which may or may not be useful in this case. I agree questionnaire could be useful for some baseline data but not the sort of depth data you look for in a case study. But it is usually recommended case studies use a mix of methods to capture complexity. Good luck.Following
- Is it possible to remove Raman background signal ?
Trying to obtain characteristic Raman signal from semi pure samples, however, the background signal from 1000-2000 cm-1 was always very strong, and this might overlap some useful signal response.
Raman spectrometer used in this study is the Perkin-Elmer Raman spectroscopy, which employed a diode laser operating system at 785 nm with average power of 100mW at the sample and 100-micron spot size.
I obtained the signal by transferring power samples onto glass slides under microscopy (20X).
This strong background signal also appeared in another SERS experiment employing nanofilm deposit onto glass slide performed on this instrument. Silver nanofilm substrate was deposit on glass slide and placed on same glass slide.
BG from bare glass slide ( without anything on it)
BG from SERS substrate ( with As III droplet on it )
Question. what is the source of this background signal ( 1000-2000 cm-1), and how to eliminate it?
Thanks for your help and input!
Thank you Dr Sofiane Saouane, for pointing out previous discussion.Following
- I wonder a reason why the PEG(polyethylene glycol) is used to experiment with DNA extration?
i wonder a reason why the PEG(polyethylene glycol) is used to experiment with DNA extraction?Following
- Why do we use equal time commutation relation in quantum field theory, what is the commutation relation if time is not equal?
Scalar field quantization
I hope it is not an aside to consider the meaning on such nonequal times results. The need for many times in quantum theory has been discussed before. The spatial coordinates must be manifold since correlations exist and relativity suggests we must have many time labels as well. The meaning of this has never been clear and we seem to have not measurement procedure to pull out much meaning from them. If we use a Schrodinger-type approach to field theory, then the reality of many times is more evident. The only solution I ever found was to consider the subset of wavefunctions in Fock space that can correspond to classical objects which then naturally induce an analog of a spacelike hypersurface with a single cone of timelike vectors at each point.Following
- Can anyone recommend papers or books about history of alcoholism in antiquity?
I'd like to read something regarding alcohol, alcohol abuse and the history of alcoholism in antiquity
Was alcohol considered a problem?
What strategies to face it?
And what about current research (regarding history of medicine or history of pathologies) on the topic?
The Society for the Study of Addiction has been around for about 150 years, and this paper regarding its origins may be of interest to you:
And this site has some victorian perspectives:
Hope this helps!
- Fermi energy in Graphene nano ribbons?
I am simulating graphene nano ribbons,and i want to add my magnetic field term in Hamiltonian,is there any other method than Pierls Substitution or not.
WE assume graphene is placed in x-y plane and B is in z-direction such that B=(0,0,B0). Therefore A=(-B0y, 0, 0) or A=(0, B0x, 0).
Now we should calculate Int(A . dl) on joining line between two nearest neighbor atoms.
- Has anyone ever assessed motivation on the 5-Choice serial reaction time task in rodents?
I'm trying to clear up some data obtained from the 5-CSRTT. Data showed some differences in both correct and reward latencies (time required to respond correctly after the onset of the stimulus and time needed to retrieve the reward after a correct response, respectively) and in the total number of trials completed. Such variables provide a measure of motivation but, apparently, the issue is quite tricky; I've read about motivational status assessment in the 5-CSRTT and the is some controversy. Could anyone shed new light on?
- Is there any gender difference with respect to obesity and the risk of osteoporosis? Obesity may not be sometimes regarded as a protective factor for osteoporosis irrespective of gender. Our data suggest that a particular obesity subgroup, namely those with higher degrees of inflammation, are a population at higher risk for vitamin D deficiency and accelerated bone turnover
There are studies showing a protective effect of obesity on hip fractures in women, but not men. I suspect that it is the difference between distribution of fat (android/gynoid) as as women tend to develop "muffin tops" that overly the hips and offer padding, while men prefer "beer bellies" and even obese men often have little fat over their hips.Following
- Problem with isolation of mitochondria from cells with percoll gradient. I have some trouble in mitochondria isolation. I purify mitochondria from HeLa Cells and for the moment I have stop my purification after the differential centrifugation step. But I need a purest preparation of mitochondria for EM studies. I try two different percoll gradient protocol.
The first one from:
Isolation of mitochondria-associated membranes
and mitochondria from animal tissues and cells
Mariusz R Wieckowski1,4, Carlotta Giorgi2–4, Magdalena Lebiedzinska1, Jerzy Duszynski1 & Paolo Pinton
and the second one from:
Isolation of mitochondria from rat brain using Percoll density gradient centrifugation
Neil R Sims & Michelle F Anderson
but int he both case I obtain only one band at the first gradient interface.
I don't really understood what is wrong.
Does anyone know whether "MAM fraction" obtained with Wieckowski protocol include only mitochondria associated ER membrane and OMM proximal to ER? or also include IMM, inner membrane space and matrix ?? If the former one is correct, I wonder how OMM and other part mitochondria can be divided.
Once I tried the protocol but COX4 was detected in pure mitochondria and MAM fraction, although in some papers it was not detected in MAM fraction. Do you have some suggestion to fix it? (I homogenized collected culture cells 300-400 strokes with tissue grinder. is it too much? or less? or alternate methods?)
I do not know here is the proper place to ask these, but I think some of you might help me.
- Is it possible to use m5RNA database on qiime?
I usually use MG-RAST for my metagenomic analysis but recently I started to use Qiime. I want to compare the alignment output after asking qiime to use its available databases and the non-redundant m5RNA database, which is available on MG-RAST.Following
- Who first coined the term dendrogeomorphology?
I have rather simple question but as almost always the answer for such question isn't so simple
Dendrogeomorphology indeed started in the 1960s, especially in the fields of flood analysis and soil erosion, but the discipline didn't have its name back in time. Thank you for the interesting link, Edurne!Following
- How can I transfect cultured cortical neurons with electroporation?
I am a new student who is going to do some electroporation on primary cortical neurons. Once harvesting cortical neurons, how much for amplitude and duration for the pulse shall I use? I am using Bio-red GenePulser, with 0.4 cm cuvette. However, I could not found useful protocol from the company for cortical neurons as well as google. Someone only mentioned the name of program they used on their machine.
So, I want to know, how many neurons and plasmid you guys used, and the detailed protocol for electro-pulse (amplitude, duration, number of pulses etc.).
Thank you, and wish you a good day!
Carla is right, cortical neurons are extremely difficult to electroporate because they do not divide. Most people forget that there are at least two membranes to pass through to get inside the nucleus. Your standard electroporation approach will only get your DNA into the cytoplasm, the second phase requires a breakdown of nuclear envelope during cell division. With that said, Lonza seems to have figured a way around that hurdle with their proprietary technology, The Nucleofector™. That platform is the only one that I know of and have used thus far (there may be other that I'm not aware of) that results in some measurable success in electroporating cortical neurons in culture. I would check them and their competitors out if you still want to electroporate cultured cortical neurons.Following
- Can anyone recommend a method for the determination of flavins, NAD(P)+/H or (extracellular) ATP in plants?
I have some plants with altered enzyme expression and I'm interested in following compounds:
- flavins (mainly FAD and FMN, not sure whether it's possible to discriminate OR to include those bound in proteins?)
- NAD(P)+ and NAD(P)H
- ATP, mainly extracellular if possible
Is anybody here familiar with methods for extraction, purification and determination of such compounds in plants (not food)?
Hi Hanna-Maija, thanks for your helpful answer.
You remove the 250ul of methanol/methylene chloride (CH2Cl2, right?) and use 100ul from that, right? To the pellet only (not pellet + 150ul of methanol/methylene chloride) you add the additional 250ul and afterwards you mix 100ul from both, right?
Unfortunately we have only UV-VIS detector, so I hope I'll be able to see something at all.
I found the second paper you mentioned. However, they use some weird buffer and I'm not sure of the composition. They write it's 0.1M ammonium acetate with 10% TCA pH 6.1, which doesn't make much sense. Mainly it's out of the buffering range for acetate (pKa 4.76) and in the end they adjust the pH of extract to 6.3, which would not be such a big change. I've looked up the original paper by group from Gatersleben, but that one is not much clearer. And nobody seems to care to reply to e-mail.Following
- How do I make a boundary layer in icem cfd?
How to make a boundary layer in icem cfd. I am doing meshing; i noticed, i don't really need a structured meshing in the far field. So wny do i not ignore it. Need to find the right tab to do the boundary layer in icem cfd.
If you have a complex 3D geometry, and you do not want to become crazy with the structured mesh, you can try the unstructured one.
There are a couple of tutorials in the Guide about tetra/prism mesh creation.Following
- How can I linearize large amounts of plasmid?
I am facing a few problems linearizing my vector for electroporation:
I want to linearize large amounts, say 50µg, of the vector (~14k bp), and have to use a rather expensive restriction enzyme (fast digest). Reading up on this I found that it's recommended to not use more than 1µg per 20µl reaction mix, so that would mean setting up 50 reaction tubes. Lastly I found that after column clean-up I have very low yield ans several trouble shooting attempts did not raise that over 40%.
So my question is are there other ways to linearize large amounts of plasmid, or how I can improve/simplify the above method to make it more efficient and increase yield?
Doing a column clean up after digestion should not be a problem; however, most standard columns have a binding capacity of only 25ug (miniprep columns and most clean up columns are only 5ug). If you're loading 50ug, then your yields will at best be 50% or worse, which is what Jose was inferring, so you will have to spread them out over multiple columns and concentrate if needed, or find binding columns with higher binding capacities or what others have suggested above (phenol/chlorofom,, etc)
Another option is to incorporate an easy enzyme site in your plasmid so that you can cut more easily (and cheaper) your bulk preps but the above conditions still apply.Following
- What is the actual absorption rate of [Calcium Citrate + Calcitriol] formulation?
Single Calcium Citrate has the absorption rate of almost 60-70%. Calcitriol or the active form of vitamin D3 is added to any calcium supplement to increase the absorption of calcium. So, in the case of Ca-citrate+Calcitriol combination what will be the absorption rate?
The lay public has been duped by the statements of superior absorption of citrate over carbonate. They assume we are talking about absorption by bone, not how fast a dose begins to be excreted by the kidneys, which is how most comparisons between the two forms are performed. The calcium ion, not its carrier salt, is what is captured in exposed bone collagen along with the other minerals, and that rate is determined by how much exposed collagen from all the BMU's in the skeleton has not completely mineralized.
Since serum calcium levels are tightly controlled, that mineralization rate is going to be constant as long as blood serum concentrations are constant. No?Following
- Looking for articles and research on ergomania and chronic pain, anyone?
I'm dealing with chronic pain in my job, and I'm looking for recent articles about ergomania in chronic pain. But most of article on ergomania are about workaholism... Any tips?
Thanks for your help!Following
- Is there anyone who can index this compounds?
In my recent work, BT-based dielectric ceramic were characterized by ex situ XRD. The XRD pattern recorded at low temperature is beyond by expection. Till now, I can not match it with any JCPDS card. The XRD pattern and data are attached.
Ian, in fact this is similar to what I have simulated (with Powder cell and the 5 pdf-inputs). So I would agree with you conclusion, that there Quilin has no phase-pure material ... at least no BaTiO3 ;-(
- How can we mark small cased caddisflies for a mark-recapture study?
We are trying to follow how a small litter-shredding caddisfly, Lepidostoma, finds leaf litter in streams. The larvae live in portable cases made of sand grains, so we should be able to mark animals for recapture by painting something on the case without poisoning the larva. Everything we have tried so far has not persisted long enough in the field. The larvae are very small (5-8 mm x 1-2 mm); we need only make a mark in a contrasting colour, not a specific number or tag. The marker must be visible, non-toxic, fast-drying (the animals can only be removed from water for a few minutes) and must persist in fast-running water for at least a week. Our best so far, oddly, has been red-coloured permanent markers. Any suggestions?
Thank you both for these useful suggestions. If I can get my hands on those permanent waterproof markers, they look like they might do the trick. I'm not too concerned about predator losses because the experiments are short-term (~ 1 week) and we are trying to see how far the larvae move about, not survival or population density. Rearing the animals in coloured sand is a cool idea, and it should work. We would have to start at the beginning of the field season (April) when the Lepidostoma are abundant but before they diapause or pupate later in summer. Maybe I'll give that a try next year.
Thanks for your help.Following
- I would like to conjugate FTY720 with Graphene Oxide for drug delivery purpose, can someone suggest an idea?
Because of the single benzene on FTY720, it would not pi-pi interact with the planar surface of GO. Although there is NH group on FTY720, we can't do EDC coupling with carboxylic acid of GO due to the needs of those NH groups during drug mechanism. I need to come up with novel idea that allows no disturb of the molecular structure yet a stable bonding. Any suggestions? Is it not possible?
Thanks for your attention and help~
You may modify the GO with some biodegradable polymer which should contain some functional group which can interact with - OH of FTY720.Following
- Which theorem states that in a sequential game the subgame perfect equilibrium is the more efficient Nash equilibrium of the game?
I remember this result was standard, but I do not find it.
there are many attempts to narrow down the set of Nash equilibrium set in classical game theory. these are called refinements.
and subgame perfect equilibrium is one of those. it's more rational, not more efficient. more rational means that it prescribes best response even in nodes that are unreached of the game. hence it weeds out strategies backed by uncredible threats in the game.
the idea of uncredible threat is credited to Schelling. Selten articulates this idea of Schelling in maths, and it's called SPE.Following
- What is the best way to purify samples (peripheral blood mononuclear cells) from RNAlater for futher usage in ELISA?
Is PBS wash an appropriate method?
RNAlater only preserve RNA.
But if you want use PBMC protein for ELISA,
Isolate PBMC freshly and store at _80 degree until ELISA assay.Following