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.
- 4Help with a calculation of triglyceride amount in liver tissue?
I extracted liver tissue (~100 mg) using Folch method and evaporated the solvent mixture and resuspended the lipid in 600 ul of dH2O (with triton x100). Then, I determined the concentration of triglyceride using an enzymatic assay. For this determination, I used only 4 ul from the 600 ul, and the TG concentration was 130.5 mg/dL. Now, I need to convert the amount (mg/dl) to umol/g and to mg/g?? Any help on this conversion would be greatly appreciated..
Sorry Sami & thank you Evelin....I totally messed up one decimal place. 7.83mg/g not /100mg.
For the molar concentration i would check if the assay measures glycerol....if this is the case the molar concentration of TG is the same, since 1 TG yields 1 glycerol.
Calculation using a single TG mass will produce a methodical mistake since liver stores a diversity of TG species and every approach to determine a mean TG mass will be very difficult.Following
- 14Any suggestion on which genus this species is?
Collected in mangrove mud.
From Southeast Brazil (São Paulo).
Thank you =)
Hi Carlo this is a good pdf. Best GianluigiFollowing
- 4Can BOD be estimated from total suspended solids?
I recently demonstrated an industrial sized horizontal centrifuge at a food manufacturing plant on their waste coming from their wastewater treatment plant (WWTP). The WWTP plant manager now wants to know what the BOD coming from the centrate off the centrifuge, back to the WWTP would be. We did not measure BOD or COD at the time but only total suspended solids (TSS mg/l) in the centrate going back to the WWTP. Is there a way to maybe correlate the BOD from the information gathered from the influent coming from the manufacturing side to the WWTP, if the TSS and BOD were recorded, to our centrate TSS?
Thank you both very much for your quick responses.Following
- NewIs capillary refill time a vital sign? or Why capillary refill time is not a vital sign?
Capillary refill time is one of the sign of dehydration and shock. Capillary refill time is widely used by health care workers as part of the rapid cardiopulmonary assessment of critically ill children because it is a marker of increased peripherally vascular resistance. I think that capillary refill time is a vital sign. What is your opinion about this topic?Following
- 1Are there other methods to detect primary cilia on the cell surface besides using immunofluorescence staining? Could flow cytometry be used?
I am trying to concomitantly assess what phase of the cell cycle ciliated cells arrest in upon drug treatment.
Dear Tiffany, Did you ever consider the use of a good quality phase contrast microscope ? There are even inverted microscopes allowing the incubation of your cells in the required volume of medium. Succes with your work !Following
- 2Is there any quick way to adaptively sample a uniform pixel grid without duplicates?
I am trying to adaptively sample a uniform pixel grid, based on a specific pixel position and a linear (or close to linear, depending on the method) falloff in importance/sampling depth based on this position.
I already have several approaches in mind and currently we rely on a sorting-based method, but it won't be fast enough at higher resolutions (currently we run 1024^2, but it could be arbitrarily high, depending on the output device).
Is there any method allowing for quickly sampling such a distribution? The main challenge here seems to be that we absolutely do not want any duplicates, which is why there has not been much progress with standard importance sampling so far.
Also, the pixel position which is used for distance computation may change all the time (from frame to frame) and we need all that stuff to be done for hundreds of frames per second with tens of thousands of samples per frame. In addition,
it would be absolutely great if such a method could guarantee a fixed number of samples being generated. This would be no problem with importance sampling, but the only way of avoiding duplicates when using this is to mark sampled pixels and
reject a sample if it hits the area of a pixel that has already been sampled, making it hard to predetermine the time the sampling step is going to take.
Does anyone know of a more elegant approach to this issue? If that's important in any way, we use CUDA for all our stuff.
Unfortunately it does change frequently, probably each frame due to the user interaction involved in the process. However, trying to exploit the distribution's symmetry might be a good starting point!Following
- 2What is J-aggregates and other aggregates of this type?
What is J-aggregates in the synthesizes of luminophores?
This link goes a little bit more into detailFollowing
- NewWhat are the effects of swelling and swelling pressure of expansive soil on below and above OMC?
Pl give me your valuable suggestions. Thanks in advance.Following
- NewHello colleagues.how can I isolate the RNA without being degraded assuming that the half life time of these fast respose genes RNA is little minutes?
I am studying the thermotolerance of a strain of salmonella that has been proved the ability to survive after exposing to temperature of 80C For 10 minutes and this strange trait for salmonella and I am trying to find the genetic basis of this heat resistance trait and the difference between this isolate and the wild type salmonella typhimurium by studying the heat shock genes DegP of HtrA protein and DnaK of HSP70 protein. the core study is finding the expression levels of these genes in the two serotypes of bacteriaFollowing
- 1What're the intersections or relations between Logistic Management, Procurement Management, and Purchase Management?
Any Venn diagram
Procurement: Function, which cares to get required but not self-produced goods or services (legally) availabe for an organization.
Logistics: Fuction, which cares to get required goods or services physically available.
Purchase: Non-strategic tasks of the procurement function (e.g. ordering through a catalogue system)
Overall: All three mentioned areas of management have to take care that the supply for an organization keeps up and running. (The right thing at the right place in the right quality in the right time at the right costs)Following
- 1How to optimize the radiation pattern in a desired direction for a smart antenna using any of the adaptive algorithm(RLS/LMS/ANY OTHER )?
Let say,we have smart antenna to radiate in a single direction but the receiver point changes point to point ,accordingly the direction & pattern.so we should link an adaptive algorithm in a feed back path to update the weights to give optimize out put.how?
you can try ZF, or ISI algorithm. Anyway you can take a look at the attached paper.
- 3How do zebra fish researchers position the fish (live and fixed) for microscopy?
I am trying to do both brightfield and flourescent photos of the heart, videos of the heart, and z-stack imaging for zebrafish embryos at 72 hpf. I use tricaine as an anesthetic and have been trying to position in LMP agarose. However, I can't seem to get the fish in the same position in order to obtain comparable data. Thanks for your help.
I have good luck with the methylcellulose. A higher percentage keeps them very still, allowing me to line up the eyes in a lateral orientation (I mostly work in brighfield). A gel-loading pipet tip (ones with the flat/scooped ends) or thin fishing line works well as a tool to orient the fish gently and quickly without damage.Following
- 5Can anybody help me with identification of pygmy grasshopper (Orthoptera: Tetrigidae), Thailand (Pa-Hin-Ngam NNP, or Tung Dok Kra Jeaw Ban in Thai)?
The question is mainly for such specialists as Sergey Storozhenko from Russia and Pattarawich Dawwrueng from Thailand (I followed their perfect article in RG, devoted to this group). Being an applicant for master degree in 1976 I made the diploma on grasshoppers of Transcarpathians even found some new for the region from Paratettix Genera. But diversity in tropical areas is fantastic...
Dorohyj Andrey, ja znaju im'ja Andriy z Ukrajiny, tomu ja dumav ščo Vy z Rossijy, ne Ukrajinec'. Prostit', bud'-laska. Ja zhoden, ščo ce možna buty Coptotettix čy Ergatettix. Ja pysatymu anglis'koju, bo bahato ljudej, jak vy vže skazaly, ne rozmovljaje ukrajins'koju, rossijs'koju čy inšym slov'janskym movam.
I agree that this could be Ergatettix as well. Thus, the only identification that would be correct in this case is Coptotettix genus group. If we would like to ID the exact species, we would need 3 photos: 1) frontal view (head), 2) lateral view and 3) dorsal view. Usually, it is not needed in some groups with less variable and obvious characters. Unfortunately, this is not such a group. You can collect similar specimens and make good photos under the stereomicrscope or try to get good macro photo with adequate lens.
I will check and compare this with some more species, especially Chinese taxa and let you know about my final conclusion.
Vsoho najkraščoho z Xorvatiji ;)Following
- 2Do you advice cage shelter to increase Austropotamobius pallipes juvenile survival against fish predation?
Some ponds used to be populated by the crayfish are now probably depleted because of newly alien fish predation on larvae. Do you advise cage shelter to protect them? Any recommendations (material, shape, size)? Vegetation is not abundant under the waterhole and natural burrows are scarce.
Fish removal is currently impossible.
Thanks for your experiences!
You could perhaps introduce more refugia by using sections of plastic pipe fixed together and weighted in a 'pan pipe' kind of arrangement with one end closed off. People use these as artificial refuge traps because crayfish shelter in them during the day so they can be sampled by simply retrieving the trap. Pipe diameter can be selected depending on the size of target crayfish and the fish you want to exclude. Attached file has some more info. Cages could work too, but more expensive and difficult to deploy and maintain, and you would need to keep crayfish stocking densities very low in cages to avoid cannibalism. Good luck.Following
- 8What are the major challenges of making Antibodies?
I am trying to isolate a specific protein from human serum. Antibodies turn out to be the most promising means for this purpose since they are selective enough to capture the protein of interest. The process of making an antibody includes several steps, starting with injection of the antigen to the animal host, extraction of the spleen and lymphocytes, induction of antibody expression into a cell line by hybrid culture and then retrieval and purification of the antibody. I need to know which part or parts of the process might b challenging?
Thank you in advance for your advice and recommendations.
Dear Reza, I agree with dr Kazansky about the approach for Ab production in rabbits. On the other hand using only 1 priming Ag dose does not garantee an optimal secondary response. There are indications, that memory formation does not need a high Ag dose. However, in the booster a relative high Ag dose is usually optimal. The abstract of a relative old publication using mice will be added (Immunology, Vol. 27, p. 747-760, 1974). In my own work with other vertebrates we have seen the same effects. Good luck with your experiments !Following
- Shian-Loong Bernard Lew added an answer in complex systems leadership theory:8I am interested in applications of information theory to social theory and in particular organization theory, management and leadership.How do formal definitions from information theory relate to human interaction dynamics in social systems? Any thoughts on this?
Authority and the culture surrounding authoritative figures are important determinants of information entropy in organizations. That is why the picture and worldview at the apex of the organization is often at odds with the one perceived at the bottom of the hierarchy. You could say that power structures distort the flow and interpretation of information.Following
- 2Equilibrium time determination between solution and head space in flavour- protein binding using head space SPME - GC?
In investigation flavour - protein binding using head space - SPME- GC, we need to recognize the equilibrium time between solution and head space at desired temperature, then we extract the released flavour in head space with SPME. Here, if we are studying a new flavour compound, how should we recognize the equilibrium time between solution and head space so that move to the next step?
Many thanks in advance
Many thanks dear Dr. Carrascal. The only information I have found till now is the distribution constant equal to 2.8 between octanol/ water phase. Actually, the flavour compound is safranal.Following
- 18Products / technologies developed are more effective than advisory services for increase of agri-production. Can we debate on this imp topic?
Examples of products/technologies- fertilizer types (customized, fortified, foliar, organic, PGP), newer pesticides, new cultivars, agri-implements, reource conservation technologies.
Few Examples of Advisory services- agro-advisory, soil-test based recommendation, yield forecasting and management options, water/tillage management options, weather based agro-advisory (although nice work but not very effective, specifically for tropical/sub-tropical regions, intensive agriculture system),
Researchers/extension workers have to exactly know the adaptation/mitigation strategies to be communicated to the farmers and other stakeholders for that region, sometimes for climate change mitigation/adaptation, the technical knowledge remains too general/qualitative, as most of the time we are applying point results for regional dissemination which may pose a problem
Same way as the crop growth is a complex process with numerous biotic/abiotic stresses, we get confused and our transfer of knowledge gets restricted to only qualitative definitions
May be it is my feeling, but still we have to strengthen our knowledge platform, on higher resolution
- 3Who knows how to install "VolArea" on VMD visualization software in order to calculate surface and volume of a molecule?
I have a .pdb file of a molecule, and I want to calculate its area and volume. I have molecular graphics software Visual Molecular Dynamics (VMD) on my computer which works in WINDOWS. I figured out that there is a complementary software called VolArea that can coupled with VMD. Unfortunately I can't install VolArea. I wander if anyone knows the instruction.
I am looking forward your help.
thank you very much.
I was able to install VolArea. I am running Windows 8.1. I used the VolArea files in the Zip folder rather than the tar.gz folder. I first installed the version of Tcl that was recommended. During the installation I needed to specify the path for my VMD installation. It worked fine, and I can see the new plugin under VMD Main > Extensions > ProtoBioComp > Surface and Volume Calculator.
If you are running linux rather than Windows, it should work equally well and perhaps better.Following
- NewWhat are some challenges when it comes to achieving the objectives and goals of an environmental impact assessment ?
Please post journal articles and give ideasFollowing
- 1Can we measure Disinvestment Policy of government of India on the basis on Target and Achievement?
The GOI adopted the policy of disinvestment of Public Enterprises in 1991 and the proceeds of disinvestment is using to bridge the gap of fiscal deficit.
I suggest the use and application of Chi square that allows one to look at target and achievements.
- 5Has anyone encountered stress # of fibula after TKA?
She has history of acute onset of pain 3 months ago, with progressive valgus deformity of the knee.
You maybe right. Fractures around the fibula are not seen in the new Xrays.
I am not sure if there is an element of rotation or even lack of full extension on the films. The knee is in more valgus than someone could expect and possibly this is one of the reasons the medial tissues gave. From the AP view seems that the fibula could be a weight bearing bone as the tibial tray is overhanging on the head and as the soft tissues gave way the load is going through the fibula more and forced the fracture.Do you think that this may be the reason? It is very interesting.Following
- NewWhat is your best second adsorption isotherm?
Everybody accept this: Langmuir is most used adsortion isotherm equation. If I ask you to porpose a second accompanying isotherm equation, what would you say?Following
- 4How to calculate SOD?
i have used the following protocol for SOD in a 5% cell homogenate..
Sample 100 ul
Phenazene methosulfate-186 mM- 100 ul
Nitroblue tetrazolium -3.0 mM -300 ul
NADH -780 mM- 200 ul
Incubate for 90 seconds at 300C
Stop reaction by adding Acetic acid -1000ul
i have calculated the %inhibition using the formula (control-sample)/control *100..... however, i am confused on how to convert the %inhition to SOD unit (per mg/gram tissue, per mg protein etc.)... can someone please help me....
Check in the reference of your procedure the substance that inhibit SOD and the percentage of inhibition. Or send me the reference to advice youFollowing
- 9Is there a detailed protocol for measuring the antioxidant activity of orange juice and orange using DPPH method?
I am presently doing a short period undergraduate project based on assessing the antioxidant activity of orange and orange juice using the DPPH method. However, upon incubating my positive control (different known concentrations of ascorbic acid, ranging from 1 to 10 nanograms per ml) with DPPH reagent, my spectroscopic readings are so inconsistent: they actually make no sense and, thus, cannot yield a useful standard curve. Could there be a detailed protocol to execute this assay successfully please? Thanks in advance.
Please do. I look forward to hearing your progressFollowing
- 3Comparing cell proliferation ratesI would like to compare the cell proliferation rate (as measured by MTT assay over time) with two different conditions given to the same cell line (plated seperately). As far as I can tell statistical comparisons of proliferation rates vary between t-test comparisons at individual time points to Kruskal-Wallis stats on regression lines. And everything in between. Can someone tell me how this is done- it must be a common enough analysis?
Your response is crystal-clear (I have understood it!).
"In contrast", I understood nothing to yours ...
Folowing the remarks of Jochen that I fully share, here attached is an article that could may be of help with respect to certain problems occuring with the MTT assay.
- 6How can I observe difference between amorphous materials and crystalline materials?
I have fused silica wafers and crystal quartz wafers. But I cannot tell any difference with bare eyes!
Should I use optical microscope or is there any suitable way to observe the crytallinity?
Additionally to XRD pattern, if you use SEM to characterize your samples, there is such a thing low angle backscattered electrons imaging, which is actually detection of electrons elastically scattered from a sample surface at Bragg angles for a crystalline specimen. Find SEM with an appropriate detector(s), operated by an expert. You could acquire "kikuchi lines" images or images of grain boundaries for a crystalline sample among with secondary images of the same area.Following
- 7A hot iron is heavier than a cold one, true or false?
Why does the same object weigh more when it is hot than when it is cold?
The reason why hot objects are heavier is because E=mc^2. If you have absolutely identical objects that have the same weight exactly when they are at same temperature, then when one object is heated, it will weigh more. This is because the gravitational force depends on the stress energy tensor in general relativity. The stress energy tensor 00 component is the total energy of the body, which includes the rest mass plus the kinetic energy of the object. Temperature differences means that there is a different amount of kinetic energy in the motion of the atoms of the two bodies.
How is it describable by massless photon (electromagnetic energy)?
Correct. When you put energy into a system, the mass of the system increases, if we define the mass of the system as the ration between momentum and center of mass speed when center of mass is moving slowly. This has not been seen experimentally, though, since the mass changes are minuscule.
On the other hand, this has only to do with the definition of mass for composite objects. It has nothing to do with photons. By the way, the statement that photons are massless is a bit misleading. Mass in this context is defined as rest mass. But photons cannot be at rest, so do not have a rest mass. On the other hand, a set of photons in a cavity *will* contribute to the mass, as stated by Charles. But it is not a good idea to try and ``add'' the photons' masses to the cavity's: it is simpler to think in terms of the rest mass of a composite body not being equal to the sum of the masses of its constituents.
On a related theme, it has been shown experimentally that iron nuclei emit gamma rays with a lower frequency when the iron is hot, because of time dilation due to the irregular thermal motion. The shift is small, but measurable and qualitatively in agreement with the theory.Following
- 2What are some problems with the sustainable development concept?
natural resource management
Sustainable production, takes into account the partial factor productivity does not devrease, for example production per kg of Nitrogen decreases if other nutrients in particular micronutrients and S are not replenished and are in deficiency, same way it goes down if irrigation water is limited for application.
Sustainable production has to take all inputs in appropriate combination, balanced form, so that environmental degradation not take place and productivity also follows the path of increased trend as noticed for that region.
But here is one confusion, should sustainable production also be associated with increased productivity as per the trend? May be not, we have to ensure higher/sustained partial factor productivity and safeguarding the environment in terms of soil degradation, GHGs emission avoided.
This of course is a difficult venture for living systems like agriculture, forestry etc
- NewHow to prepare 10 g/L H2O2 solution from 35% H2O2?
I working peroxicoagulation process with 850 mL reactor volume, and the final concentration in the reactor should be 10 g/L. How to prepare 10 g/L hydrogen peroxide from 35% H2O2 solution? Thanks in advance.Following