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.

Browse Topics

  • Rasiq Kelassanthodi added an answer in Polycyclic Aromatic Hydrocarbons:
    Is there any alternative recovery Internal standard for PAH instead of deuterated one?

    I want to analyze PAH from sediment and aerosols, we don't have deuterated recovery internal standards. Please let me know is there any alternative available for this deuteriated PAH?

    Rasiq Kelassanthodi

    Dear Guillaume ten Dam ,

    we are doing extraction for both PAH and PCBs simultaneously.

    so PCB won't work! 

    Any other suggestions please.

  • Napoleon Ono Imaah added an answer in Poverty:
    How does poverty affects one's well-being?

    In a developing country, I presume the way poverty is perceived is quite different from that of a develop country. How will poverty then affects ones well-being in a developing country? (most especially women). Will be nice if you can bullet point it. Thank you

    Napoleon Ono Imaah

    Poverty ruins a person with want, particularly  when poor is noticeably worse than others around. Poverty makes a person insecure and incapable of meeting vital obligations to self and dependants. When the poor compares self deficient, compared to others, in access to the good things that make life good, sorrows set in, Thus, poverty is poverty and poverty is available both in developed and developing countries.

    However, social services: healthcare services; infrastructure and governance are more qualitatively accessible to the poor in the developed countries seem to fare better than the poor in the developing countries. Otherwise, poverty is poverty as a tell-tale woeful sign of inequality everywhere .

  • Musa Eşit added an answer in Ternary Diagram:
    How can I plot a ternary diagram between hydraulic geometry parameters including coefficients and exponents of river discharge?

    I dont know how ı can plot ternary diagram between parameters?

    Musa Eşit

    Thank you dear Arabzadeh...

  • prof V.S Muralidharan added an answer in Negative Results:
    Why is there negativity towards publishing negative results?

    Many experimental results never see the light of publication day. For a large number of these, it comes down to the data being “negative”, i.e. the expected and/or wanted effect was not observed. Despite their potential, negative results are repeatedly relegated to the lab books, the drawers and the trash bins. Prof. Dr. Anthony Cerami once said "Many of the biggest discoveries of my career were the results of failure of another research project. ... Failure strikes a negative tone, but it appeared in my personal history that it was an essential experience on the path to important discoveries.".Should researchers publish their negative results?

    Some new journals like "Journal of Negative Results in Biomedicine" or "New Negatives in Plant Science" encouraging researchers to publish their negative results. But as you know, there is a negativity towards negative results. Why negative results not published by journals as freely as positive results? Is it time to publish research “failures”, too?

    + 1 more attachment

    prof V.S Muralidharan

    Dear friends. Publish. No one has a final say in science

    Feel free 

  • Janusz Rebis added an answer in Plastics:
    Which plastics can survive in the temperature between 40 - 70 degree celcius in duration time of one hour?

    Which plastics can survive in the temperature between 40 - 70 degree celcius in duration time of one hour? I want to do experiment in producing biodiesel.

    Janusz Rebis

    PE should be ok, but ask DuPoint if their polymer meets your requirements. Usually, PE is chemically resistant and its melting temperature is above 110 C degree.

  • Krishna Swamy added an answer in Crowdfunding:
    What is your attitude towards Crowd Funding project creators?

    Participate in my online research and you will assist me in determining what impact, if any, a Crowdfunding project creators identity has upon potential contributors. The research requires 250 respondents, so your assistance will be greatly appreciated.  Please follow this link to participate: http://crowdfundinglab.weebly.com

    Krishna Swamy

    Done !  Please share your research results.


  • Morteta H AL-Medhtiy added an answer in Zymography:
    Does somebody have a good step-by-step protocol of zymography for assessing matrix metalloprotein activity?
    I have to check whether it is matrix metalloprotein activity in extracts that we have got. We can't afford antibodies.
    Morteta H AL-Medhtiy

    Dear Tania and all researcher in this group

    Can you send me the catalogue no. of ''Gelatin'' and ''beads'' please?

    I am ordering stuff for Zymography  and need advice from expert already done the experiment. I am in very critical time and need help please....


  • Chithan C Kandaswami added an answer in Caspase 8:
    What other ways could a treatment to cancer cells result in apoptosis?

    A treatment to a cancer cell line resulted in apoptosis (specifically a kit mesured DNA fragmentation). Caspase 8 and 9 levels were measured and were shown to be low. What other tests should be run to determine the source of the apoptotic trigger? Thanks.

    Chithan C Kandaswami

    Investigators have identified a new mechanism that the tumor suppressor protein p53 employs to trigger cell death via apoptosis.  They have reported how p53 acts in the cytoplasm to trigger cell death by binding to and activating BAX. 

    Ariele Viacava Follis, Fabien Llambi, Parker Merritt, Jerry E. Chipuk, Douglas R. Green, Richard W. Kriwacki. Pin1-Induced Proline Isomerization in Cytosolic p53 Mediates BAX Activation and Apoptosis. Molecular Cell, 2015; DOI: 10.1016/j.molcel.2015.06.029

  • Ichun Chen asked a question in Trizol:
    Cell pellet in trizol and subsequent RNA extraction?


          I have isolated some mouse splenocyte and collected the pellets after isolation. I added QIAZOL into the cell pellet, but I forgot to pipette it up-and-down before I put it into the -80 freezer. The yield of the RNA extraction was not very good after that. Is it still possible to do something at this point or it is all gone...? If I transferred the QIAZOL/ Cell pellet into another round bottom tube and use homogenizer/ round beads to destruct the pellet+ QIAZOL, is it still helpful? So sad to notice that I should have homogenized the cell pellet before I froze them...

    Thanks for everyone's input.

  • Thomas McCloughlin asked a question in Species:
    Does anyone have a technical definition of biodiversity?

    Is there an equation for a numerical score of biodiversity that captures richness of certain 'types' of species as well as the abundance of such representative species in a given ecosystem?

  • Ipek Deveci Kocakoç added an answer in ANN:
    Classifiaction problem with ANN
    I am trying to classify my data into two groups with ANN. There are two inputs and the output is 0 or 1. I use MLP with backpropogation. The net does not learn well and so can not classify well. Do you have any suggestions about the activation functions, network structure, etc. for classification?
    Ipek Deveci Kocakoç

    Sorry, I have not worked on classification with ANN. However, one of my collequages tried it and was not satisfied by the performance of the ANN, whatever he tried.

  • Charles A S Hall added an answer in Climate Change:
    Are there authentic published work confidently pinpointing the sole anthropogenic factors contributing to Climate Change?

    Combined natural and anthropogenic factors (geologically recent phenomenon) govern Climate Change. It is, therefore, of paramount importance to discretely recognize the role of humans in Climate Change and to plan efficient strategy to mitigate it.

    Charles A S Hall


    I do not disagree with your text but do not understand the graphs. You have global year over year as high as 9 percent (I assume this means that in 1987 there were 9 percent more people than in 1986) going down to 8 percent.  But global population growth has been about 1-2 percent during this period,   So what a I not understanding? 

    The second graph implies that the per capita release of CO2 is about 1 million tons carbon.  That cannot be true either. 

    I guess the last two graphs indicate that nuclear electricity (by implication our salvation?) has become asymptotic while the population and CO2 continue to increase.  I guess that is true. 

    Since I respect your posts I want to make sure I understand them. I certainly agree that any discussion of "sustainability" while the population (and general desire for increase affluence) continue to grow unabated.

    Charlie Hall 

  • Tanisha Jowsey asked a question in Journalism:
    Should authors be asked to recommend peer reviewers for their submitted manuscripts?

    I recently had a lot of difficulty in identifying potential reviewers for my manuscript that could meet the criteria of a)being unknown to me, b) not having worked with me in the past five years, and c) not affiliated with my institution. IT was enormously frustrating trying to identify someone who I thought could actually provide a constructive lens on my work. That same day I received a manuscript back from the journal who had kept it for four months, only to tell me that they could not find suitable reviewers and were therefore dismissing my paper and making it ineligible for re-submission to any of the BMC journal series. Friends, what do we think of this?

  • Faris Alshubiri added an answer in Human Resource Management:
    Strategic human resources management

    explain strategic human resources management

    Faris Alshubiri

    Dear Heerowa Gaurav


    I think the strategic is long term plan include the procedures how to implement the plans in firms , that's mean a vision for the for the firms in the future , one of main factor of any strategy is human resources management . The HR is play a vital role of success any firm if the employees work in efficiency and effectiveness concepts , that's may be affect of profits in the future and development and growth of firms .

    Best Regards 

  • Alexander H. Jack added an answer in Traumatic Stress:
    Is it valid to ask participants to report on their parents' exposure to traumatic events?

    Is it valid to ask participants to report on their parent's exposure to traumatic events?

    For example, asking a participant to rate their parents' exposure to community violence, discrimination, abuse etc. 

    Are there any good examples of this in the literature?

    Alexander H. Jack

    Hi Tanisha, Many thanks for your reply - I agree with what you say. 

  • Jonathan Pilote asked a question in Gene:
    Where can I find these bacterial strains?

    I am looking for two strains.

    1. Bacteria containing the blaCTX-M-1(15) gene

    2.Bacteria containing  the czrC (copA) gene.

    I am looking for these genes in order to build a standard curve for a PCR experiment.

    Thank you for your help.

  • Gabriel Osvaldo Gallo-Oller added an answer in Cell Line:
    Could anyone explain the nomenclature of MG63 cell line?

    Could anyone explain the nomenclature of MG63 cell line?

  • Faris Alshubiri added an answer in Financial Markets:
    What are the main factors, in Financial markets, that influence the desire to buy or sell? In which sens?

    I thought it includes: excess demand (demand and supply), corporate reputation of the market, purchasing power of the trader and some times urgency. Do you see the same factors? 

    Faris Alshubiri

    Dear Janvier Ukwizagira


    I think it is related to many factors , internal factors such as size of firm , net profit , capital structure , also external factors such as laws , interest rate , exchange rate , balance of payment . As you see there are many items need to test to know which factors is  most significantly and related to financial markets ,

    Best Regards

  • Daniel Moreno Soto added an answer in GeneSpring:
    Are there other interesting and informative analyses using Microarray Data?

    I've not gone much beyond looking at differential gene expression between type and state in GeneSpring and using KEGG to assign function. What other methods and techniques do people use, have you tried to look at heritability or are there other interesting and informative additional analyses using the microarray data?

    Daniel Moreno Soto

    There are many methods and tools to explore microarray data beyond the classic fold-change; you should read about Clusterin Methods (specially Self Organizing Maps, or SOMs) and Gene Set Enrichment Analysis. As the other answers, I also suggest, as mucha s possible, to include a systems perspective.

  • Hamid Sharif Nia added an answer in Repeated Measures:
    How are the variables adjusted in repeated measurement test?

    How do adjusted variables in repeated measurement test?

    Hamid Sharif Nia

     Dear Dr Özkan Görgülü 

    Thank you so much. I want to adjust some variables for instance sex, educational level and age simultaneously when i am running a Repeated measurements in SPSS. We have two groups (case-control)/ Variable dependent is a continuous variable (Three measurement). Is that possible by SPSS?

  • prof V.S Muralidharan added an answer in Cyclic Voltammetry:
    How can I coat the working electrode sample on the Nickel substrate for taking electrochemical studies?

    How can I coat the working electrode sample on the nickel substrate for taking electrochemical studies?

    prof V.S Muralidharan

    Congrats gomathi  varagur@yahoo.com

  • Anton Beletskii added an answer in Cytotoxicity Assays:
    I am planning to use cycloheximide for inhibiting protein synthesis in HeLa cells. What concentration should I use?

    I need to know what concentration of cycloheximide can be used in HeLa Cells without killing the cells. According to Santa Cruz Biotech that sells this compound, IC50 value of CHX is 532nM for Hela Cells. I have also read that this value is cell line specific. I have come across papers that have used it at 10-30ug/ml for this cell line. But I also calculated that 532nM corresponds to 0.14ug/ml conc of CHX. So they are using it at very high levels. I want to avoid doing a cytotoxic assay, so I would need valid references for supporting the use of a specific concentration of CHX. I plan to use it for 3-4 hours in HeLa Cells having overexpressed luciferase and want to inhibit any protein synthesis after i give the cells Heat Shock. Also, I think I have to add CHX after Heat Shock treatment, but please confirm if it is otherwise.

    Anton Beletskii

    1-20 ug/ml for 4-24h, ideally do a pilot Western blot expriment to see if your favorite protein marker disappears as a result of the treatment. Ubiquitin is a good sensitive  marker for Cycloheximide treatment.

  • Luke Boyce asked a question in Algebraic Topology:
    How do I see that M has the same integral homology as S^n?

    Let M be a compact connected n-manifold without boundary, where n ≥ 2. Suppose that M is homotopy equivalent to ΣY for some connected based space Y. How do I see that M has the same integral homology as Sn?

    Here is an attempt. First, recall that a suspension has no nontrivial cup products. By Poincaré duality, it follows that the integral cohomology of M is torsion in degrees 1 through n - 1, and that the same is true of the integral homology. From universal coefficients, we know that Hn-1 is torsion-free, which here implies that it is trivial. By Poincaré duality again, H1 is trivial, so by universal coefficients again, H1 is trivial, and by Poincaré duality again, Hn-1 is trivial. Now we can repeat the cycle: universal coefficients now imply that Hn-2 is trivial, etc.

    However, the above hinges on the assumption that M is orientable. How can we bypass this?

  • Edielson Prevato Frigieri asked a question in Wireless Sensor Network:
    How to access link quality in Wireless Sensor Network?

    What are the the best link quality metrics for Wireless Sensor Networks and how they are related to the nodes transmission rate and link capacity?

  • Hossein Khorasanizadeh added an answer in Vapor Pressure:
    How to calculate how much amount of vapor will be generated and what will be its P & T from one liter of a liquid which is at room temperature?

    I have 1 Lit of liquid at room temperature. I want to sail it. I packed it in 5 lit container of HPDE (With proper primary and secondary packing) at normal conditions, but container broke due to generation of vapors and high pressure of generated vapors.  I want to fix a container size and also material of container. For that I want to calculate how much amount of vapors will be generated and at what pressure and temperature will they be, if I pack 1 Liter of my liquid at room temperature.

    (Vapors were generated during road transport, may be because of vibrations and collision with other consignments. This is just one of the possibilities.)

    Hossein Khorasanizadeh

    Dear Vedraj Awate

    Please note that:

    1) Transition to vapor phase of any liquid kept in a container with initial room temperature (and say initial ambient pressure) needs temperature enhancement.  This requires heat transfer.

    2) To know the saturation pressure of a fluid at any given temperature there is no way other than performing experiment. After doing experiments for the desired  temperature range you will be able to find the vapor pressure relation.

    3) Also to know the change of specific volume due to phase change again you need to perform experiment at different constant saturation pressures.

    4) After the above mentioned procedures you will be able to know the pressure at any container temperature as well as the amount of produced  vapor at such pressure when all of the liquid changes to vapor.

    Ps: Please notice that when the temperature of the container (and its contents) rises up, the pressure of its fluid content rises up either. This is why your container was broken out.

  • Arman Ehsani added an answer in Leaching:
    Is leaching of malachite copper ores with ammonia possible as a substitute of sulphuric acid?

    Part of a project title: Investigating the effectiveness of ammonia/ ammonium sulphate as a substitute lixiviant to sulphuric acid leaching of copper at King and Queen Copper Mine.

    Arman Ehsani

    In general, you can use Ammonia as reagent to extract copper from carbonate minerals. However, you should notice the Eh-pH (pourbaix) diagram and stability of ions in the leach solution.

  • Faris Alshubiri added an answer in Corporate Social Responsibility:
    Which factors/indicators are relevant to evaluate a company’s CSR performance?

    Please recommend me some perspectives that should not be missed when evaluating CSR performance.

    Faris Alshubiri

    Dear Catalina Crisan-Mitra 


    I think it is related of any item or variable related to society service , some firms participate as percentage of net profit  and present to society  to build hospitals , schools ...... etc  , also mean treatment of customer as transparency  .

    Best Regards, 

  • I. V. Fedorchenko added an answer in Phase Diagrams:
    Can anyone share the experiences of investigation of the phase diagram of alloys which are unmixed in liquid state?

    What is the main attribute of such mixture? Can it be predicted somehow? Calculated?

    I. V. Fedorchenko

    Dear Collegues, thank you all.
    I construct CdSnAs2-MnAs phase diagram. Based on the previous research (ZnSnAs2-MnAs) I think the section is quasibinary.
    I prepared compounds with 0, 10, 20, 30,40, 50 mol% MnAs and the samples from 10 till 50 have the same temperatures peaks on DTA. If the eutectic is somewhere between 0 and 10%, I have to have the changes in liquidus from MnAs side. But I haven't. I thought to calculate the theoretical Te, but I didn't find H(fusion) for MnAs. I decided to growth the eytectic composition 95mol.%CdSnAs2-5mol.%MnAs using Bridgeman technique, but 2/3 of the crystal is pure CdSnAs2, on the top part I found Mn2Sn and CdSnAs2. Plus it has a strange forms, not eutectic and situated random. So, may be the growth crystal is wrong, but what can be wrong with first 5 samples? x-ray is ok.
    Of course, I made a decision to start all from the begining, but to have a double checking, I would like to calculate it. Can I calculate it somehow without the entalpy of fusion?
    thank you in advanced.

  • Achim Treumann asked a question in Noise:
    Is there a standard method for separating technical variability from biological variability?

    We have a proteomic dataset where many proteins have been identified in samples derived from two classes of samples with three biological replicates each. Each of these samples was analysed (injected into an LCMS instrument) twice, generating a technical duplicate (this means, that we have 12 LCMS results in total, six sets of duplicates). We have used a technique (SWATH) where we have essentially no missing values for any of the proteins.

    When playing with the data (e.g. making a x-y graph where two different replicates are compared to each other), it is clear that (as expected) technical noise is much lower than biological noise (differences in protein abundances between different sample sources).

    Can anybody advise me how this observation could be quantified? As we only have duplicates for each sample, we cannot work with standard errors when trying to capture technical variability. If we just take the difference of a value between technical duplicates, we neglect that we have duplicates for EACH sample. What does the average of the six differences tell us and how can this be related to the average of three means in each class?