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

  • What types of heaters are suitable for mimicking heat generation from electronic chips?

    Trying to mimic heat generation from tablet computers.

  • How can I calculate the dissipated energy in transmitting and receiveing process using the transmit and receive currents for WSN???

    I know how I calculate the dissipated energy using the first order radio model for wireless sensor network. But, if I know the transmit and receive currents of node, then how I calculate the dissipated energy ???
    Is the distance bet. transmitter and receiver haven't an impact on calculation of the dissipated energy in this case?

    Tauseef Ahmad · Aligarh Muslim University

    Yes, distance between transmitter and receiver plays an important role in calculation of dissipated energy. You can use RSSI model for energy calculation.

  • How does a leader manages the complexity in organization?

    Traditional approaches of leadership are less and less useful given the rising complexity of our modern world. Complexity leadership theory offers new perspectives to overcome complexity constraints in organization; but tools that a leader could use to manage the complexity are not yet well specified. Any opinion about this issue will be useful for my research.

    Sergej Van Middendorp · Fielding Graduate University

    Hi Mahmoud,

    A key place where complexity and leadership are discussed is the International Journal for Complexity in Management and Leadership.

    In defining complexity, which is complex in and of itself, a beautiful and recent resource is Tarride's article:

    Tarride, Mario Ivàn. “The Complexity of Measuring Complexity.” Kybernetes 42, no. 2 (2013): 174–84. doi:10.1108/03684921311310558.   And my personal view is that a combined ontological and constructive approach is most valuable. For the former, see for example Snowden, for the latter, Stacey.   Kurtz, Cynthia F, and David J Snowden. “The New Dynamics of Strategy: Sense-Making in a Complex and Complicated World.” IBM Systems Journal 42, no. 3 (2003): 462–83.   Stacey, Ralph D. Complex Responsive Processes in Organizations: Learning and Knowledge Creation. Kindle version., 2001. www.amazon.com.
  • Sanjeet K. Verma asked a question in Inoculation:
    Has arbuscular mycorrhizal fungi (AMF) any role on seed germination?

    I have done an experiment in which i have sowed Cymbopogon seeds in the soil inoculated with different strains of AMF (Glomus spp.) and a control in which AMF was not inoculated. 

    The seed germination of AMF treated pots was significantly high as compared to control.

    Is there any mechanism/literature known which indicate the influence of AMF on seed germination.

  • Is relative simultaneity a misinterpretation of Special Relativity?

    I really need a lot of feedback on this particular issue.

    I think that relative simultaneity is a computational effect of no consequences to real temporal relations. This is based on my analysis of simultaneous trajectories.

    My claim of apparent nature of relative simultaneity is based on the assertion that relative lengths of rigid objects or points moving at a constant relative distance to each other in a stationary system are not conserved (in general ) in the moving system after Lorentz transformation when expressing multiple points trajectories in terms of common time of the moving system.

    More details in the linked document and relevant draft article available from my RG profile

    Stefano Quattrini · Ordine degli ingegneri della provincia di Ancona


    "If experimental evidence were to show the hypothesis to be false, then the theory would have to be modified by introducing an explicit acceleration-dependent and gravity-dependent deviation of “clock time” from “proper time”. But there is no such effect in the currently accepted version of Relativity (SR and GR)."

    Yes...it is an application of the least action principle and does not depend on the acceleration directly.

     But nontheless I think that it has to be considered as a "proper pace"...thought giving the same results. Everything should be recalculated with the variable speed of light which is variable according to the mass/energy (as a generalization of a local stress tensor). THis  will make the GRT and SR merge, otherwise that SR is just a local restriction of GRT to flat space-time wipes out interactions in both  GRT and SR.

  • Hendrik Gremmels added an answer in Hyperemia:
    What are the main pathways of eNOS activaton?

    I need some information , in addtion is the Flow-Mediated dilatation a good tool to explore potential NO-releasing drugs, as it is only basing on  hyperemia and eNOS release caused by potassium and calcium flow. Is it possible that drug that activates eNOS in other way will not cause any effect in this experimental set-up? 

    Hendrik Gremmels · University Medical Center Utrecht

    Hi Michal,

    The acitivation of eNOS is a pretty complex process and there are a host of different factors involved. In principle the primary activation pathway is via intracellular calcium influx, which is a second messenger system that can be activated by several chemical and mechanical stimuli.
    eNOS activity is also regulated by phosphorylation on a number of Ser/Thr/Tyr residues (7 I think), which occurs in response to various stimuli like VEGF, Insulin etc.

    FMD is a good tool in vivo and needed for final validation of potential drugs. Is your question if there any false negatives? I would imagine so, as some drugs that activate eNOS have broad systemic effects. Think for instance of insulin, which is a well known eNOS activator that might be imprudent to infuse without special measures.
    For screening of eNOS releasing drugs on a large scale you can better look at in vitro systems that are easily multiplexeable
    DAFDA is easy but prone to interference and therefore out of favor, ESR is an option, but not multiplexeable. The Griess assay can work quite well in some circumstances, it all depends on what you want to do exactly :-).

  • Surendra Ambegaokar added an answer in Cosmids:
    Any suggestions of how to obtain a clone (preferably cDNA) for a Drosophila melanogaster gene with the full-length 5'UTR intact?

    Most cDNA libraries I have looked at are vague at best about what their full sequences are, let alone the 5'UTR (as most cDNA tend to be sequenced from the 3' end).  

    Should I just get a BAC/YAC/cosmid of the gDNA and subclone out the regions I want from there?

    Surendra Ambegaokar · Ohio Wesleyan University

    Great idea!  The only problem is that I am looking for a more rare variant, and I don't know exactly when and how much is expressed, so it'll just take more work than I wanted to expend in checking to make sure I am getting the right variant.  But, this does seem like the best way to get exactly what I want.  Thank you!

  • Armin Rajabi asked a question in Nanomaterials:
    Does anyone know how we can measurement variation of hardness with grain size?

    The hardness of a material is generally related to the grain size through a Hall-Petch equation (HV=Ho+Kd-1/2). So, in a nanomaterial that consists of different size how can find variation of hardness with grain size.

  • Roberto Molteni added an answer in Food Additives:
    How do we overcome the risk assessment drawbacks of using plant/plant extracts as food/ food additives?

    The chemical characterization of plant/plant extracts is usually less than 100%, although there are fast, cheap and sensitive analytical methods. Moreover, phytochemical markers are sometimes the only compounds mentioned!

    Plant/plant extracts have high chemical variability, even if obtained from same chemotype and manufacturing process. It is technologically feasible standardise some components; however, not feasible for all components of the extracts!

    Roberto Molteni · Ministero delle Politiche Agricole e Forestali


    The first step of the risk assessment is the hazard identification and in the traditional use there is not usually sufficient information.

    If the plant is traditionally used, it does not ensure that all toxicological endpoints have been checked.

    For plant extracts, for sure we must identify whether extracts are free from any toxicant, however, plant extract composition are usually less than 100% and toxicants could be in the unknown part.

  • Andreas J Kesel added an answer in Bromination:
    How can I carry out bromination?

    Can anyone suggest the synthesis of 5-(2-bromoacetyl)-1,3-phenylene diacetate(CAS: 36763-39-0) from 3,5-diacetoxy acetophenone(CAS:35086-59-0) ?

    Andreas J Kesel · Independent Researcher

    a good method to avoid handling the bromine is to brominate acetophenones with cupric bromide [copper(II)-bromide, CuBr2] in heterogenous suspension (refluxing in chloroform/ethyl acetate). Take a look on the recommended paper. Be aware that some phenacyl bromides are highly irritating (tear gas) and difficult to isolate depending on substitution pattern. Phenacyl bromide itself is crystalline (mp 50°C) at standard conditions with strong lacrimator effect (highly irritating vapors).

    How to undertake borominathion in a laboratory?. Available from: https://www.researchgate.net/post/How_to_undertake_borominathion_in_a_laboratory/1 [accessed May 28, 2015].

  • Vikas Kohli added an answer in Ileostomy:
    What could be the most appropriate treatment approach for a 3-month old infant with congenital superior vena cava stenosis?

    A 9 days newborn has been operated on for necrotic perforation of the small intestine and a double-barreled ileostomy was carried out. Postoperatively the child develops ascites and chronic jaundice. Liver ultrasonography revealed hepatic fibrosis. At the second month after resolution of symptoms the echocardiography establishes a congenital superior vena cava stenosis. A second stage surgery is foreseen - namely a closing of the ileostomy. What next?

    Balloon it. Stunting would be limited by growth

  • Abu-Eid I Sameer asked a question in Metformin:
    Can anyone help in finding papers about the acute and chronic treatment of metformin in rodents?

    I need papers about the effect of the acute effect of metformin in rodents as well as the chronic effect. I need to know which doses they use and which rout.

  • Tauseef Ahmad added an answer in Network Simulators:
    Is ns2 or ns3 most suitable to study routing in for wireless sensor networks?

    implementing and evaluating a routing protocol for wireless sensor network can be made by ns3?

    Tauseef Ahmad · Aligarh Muslim University

    In case of wsn, It is better to work on ns-3. 

  • Why doRadioactive Gels get blue patches when dried and incubated with X-ray Films?

    I am doing radio active protein gels and after running a normal SDS-PAGE gel I dry the gel between two cellophane papers (incubated in water) and allow them to dry completely. This is followed by Incubation with the X-Ray film in a cassette at -80 degrees. The gels have a blue patchy colouration on them after incuabtion for 24 hours which is also faintly visible on the X-ray film. I am worried that on longer exposures and longer incubation in the developing solution it might be more visible. Has anyone faced this before? If so how to get around it?. And any other more efficient way of visualising radioactive gels / blots would be appreciated

    Michael Marcus Hoffmann · Universitätsklinikum Freiburg

    Do you stain the gels before drying or do you dry the native gels? Are you working with 35S? Decades ago I have used this isotype for sequencing but I never got blue gels, only white ones when the urea remained in the gels.

  • Ma Ay added an answer in Elastic Modulus:
    How do I assign viscoelastic material properties into Abaqus?

    i am simulating the behavior of tissue on Abaqus

    i want to assign those material properties please:

    time-dependent viscoelastic properties were assigned to the cytoplasm using this model (E0 = 6.5 kPa, E∞ = 4.3 kPa, ν = 0.5, τ = 15.4 s), where E0 is the instantaneous elastic modulus, E∞ is the equilibrium elastic modulus, ν is poisson’s ratio, and τ is the characteristic relaxation time.

    anyone can help

    thanks in advance

    Ma Ay · The German University in Cairo

    Mr. Mohamed,

    this is the Input file of my model

    i am trying to indent 30% of the hight of the box

  • John Machell added an answer in Water Pumps:
    What is the effect of increasing NPSH available on a pump discharge?

    does changes in liquid level in tank affect the discharge rate of pump?

  • Homotopy Analysis Method
    Hi, I am working on Homotopy Analysis Method for solving strongly nonlinear differential equations. To discuss about HAM and new developments are welcome.

    Hoang Duc Truong · Đại học Sư phạm Hà Nội 2

    Dear Zue Sadi. I've sent you the book that you need.

  • Vilmantas Gegzna asked a question in Indicators:
    Author indicated incorrectly

    In this article the 3rd author indicated incorrectly. The author should be prof. Lil Valentin from Lund University (link to her profile added bellow). How can this error be corrected?

  • Is possible to follow Zebrafish develop in diluted E3 medium?

    I'm trying to see the development of Zebrafish embryos (4hpf-96hpf) in dilutions of E3 medium in deionized water: 2%, 4%, 6%, 8% and 10% of E3.

    I put the 5 embryos in well in a 24 well plate and do static system (did not change the medium during all the time).

    All the embryos in the dilutions have normal development until 72hpf after this time they have malformations, pericardial edema, slow heartbeat and they died in 96hpf.

    I do some wells as control with 100% E3 medium and the embryos were fine in these wells.

    I really do not understand what is happening. If someone can help me with anything about this I would be very grateful!

    Carolina Barbara Oliveira · National Institute of Metrology, Quality and Technology (Inmetro)

    Hi Alejandro, Thanks for your answer!

    I add in well 1ml or 5 embryos but I'm not changing the medium everyday. I realy don't understand what happened.

    I will try again one more time changing the medium everyday.

    Thanks again!

  • Abdulwahab Benhadji asked a question in Pdf:
    Anybody have "FERROUS WIRE HANDBOOK" with pdf format?

    Anybody can send to me "FERROUS WIRE HANDBOOK" in pdf format?

  • Yang Liu asked a question in RNA-Seq:
    How to get the differentially expressed genes in cancer cell lines?

    I'm wondering is there a way to calculate the differentially expressed genes in cancer cell lines(e.g.,MCF7)? The gene expression data (microarray or RNA-seq) for cancer cell lines can be found in many projects, but corresponding normal cell does not exist. Is it sound to use the corresponding normal tissue(e.g.,breast) gene expression for the calculation, such as the Illumina Body Map? Or is there any project to characterize the genome features of these cancer cell lines?

  • Which simulation tools can be used?


    I am working on Network virtualization for smart grid communication.

    Can any one please suggest me the simulation tools that can be used??


    Pau Fonseca i Casas · Polytechnic University of Catalonia

    From the point of view of the model representation, and since you are focused on the modeling of an Smart Grid, I recommend Specification and Description Language (SDL), graphical, non ambiguous and easy to use (other good alternatives exists like DEVS or PetriNets among others).

    From the point of view of the implementation of the model, if you chose SDL you can use specific SDL tools (automatic implementation from the specification). The same if you select DEVS or PetriNets to define the model behavior.

    Also some specific tools exists to represent networks, like OMNET++ and OPNET.

  • How can i cover back contact of my CIGS solar cell through deposition & selenization?

    I'm fabricating CIGS thin films by RF sputtering followed by a high temperature selenization process. I tried using polymer to cover then remove the covered area by organic solvent but it didn't succeed.

    Krishna Nama Manjunatha · De Montfort University

    1) You can cover it with photoresist  and you will also find chemical where you have to dip in to remove photoresist. 

  • Md Faruq Hossain asked a question in Solvents:
    How to remove air bubbles from the solvent channel??

    Unfortunately, during changing the solvent binary pump was on and some air entered to one of the solvent channel in my LCMS. I am not getting proper volume of solvent in that channel. Can anyone help me sort out how to remove the air bubble from the  solvent channel. I am not sure if bubbles trapped also in column.

  • How much is the acceleration time history representative for ground response analysis?

    Some measurements during Nepal earthquake were obtained on 3rd storey of building. How can we do correction for concrete? Or simply this is good enough for ground response analysis?

    Aleksey A. Emanov · A.A. Trofimuk Institute of Petroleum Geology and Geophysics SB RAS

    Probably not. Building has physical dimensions. Every dimension has it's own resonance characteristics. So you can imagine building as a linear system (assuming there was no destruction or cracking of the walls) which has many resonances you even do not know exactly. So on the third storey you would record not a ground motion but the response of the building to the ground motion and the transfer function is quite unclear. Surely should be amplification caused by resonating building, so amplitudes will be much higher then on the ground.

  • What is the meaning of on-site energy?

    Hey guys,

    Can you explain the meaning of "on-site energy" in the following context?

    The edge carbon atoms of our GNRs (armchair graphene nanoribbons) are passivated by hydrogen atoms so that the σ bonds between hydrogen and carbon and the on-site energies of the carbons at the edges would be different from those in the middle of the GNRs.

    Thanks in advance,


    Luis Villamagua · Universidad Técnica Particular de Loja

    Wow that was neat Alfredo. And nope; I do not know much about the TB model. I am currently studying GNRs and simulation methods. I work with DFT though. Do you have any bibliography that can guide me? For example, I have seen that the parameters for TB simulations are taken from experiments or from DFT simulations. Do you have literature on this regards you can share (like a tutorial)? Thank you in advance

  • Helena Pestana added an answer in Data Analysis:
    Is this Interpretation of ODA outputs correct?

    Each FA and AM are groups of variables all analysed in a scale 1 to 4.

    The restricted range of values + violation of multivariate normality make unreliable goodness of fit statistics (ML) and standar errors. Then I aplly optimal data analysis paradigm, instead of FA or PCA.

    Do you agree with the interpretation of ODA outputs and the way I analysed data?

    Thank you


    Helena Pestana · ISCTE-Instituto Universitário de Lisboa

    Thank you.

  • Where is the problem in bandstructure calculation. It is showing values on Y-axis only below 0 eV ?

    It is showing only valence band. There is no energy values in conduction band. I have attached here KPOINTS file.

    Shilendra Kumar Sharma · Indian Institute of Technology Kanpur

    Can you give me that script and also tell me how will use .

    My email id is shilu@iitk.ac.in

  • Sujata Sharma added an answer in Splenocytes:
    Hi, I am trying to proliferate T cells using Splenocytes for some reason I am having issues - - Am not sure why I do not see any division peaks?

    1. I am using DMEM+10% FBS+ pen strep to culture the splenocytes.


    1.10ug/ml of anti mouse CD3 (coated); 5mg/mL of  CD28. Or

    2. Dyna mage -2uL per 8*10^4 cells ( as suggested).

    Splenoctes are processed , RBC lysed and CFSE stained before the stimulus is added.1 Million cells per well ; 12 well plate 4 days post incubation used FACS read out.

    Compared both Balb c Mice and Black 6 mice .  - same results no division peaks.Is there any thing I am doing wrong?

    Thanks for the help! I will try those reagents