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  • Garima Joshi added an answer in Langmuir Probe:
    Why there is a glitch in ion saturation current?

    I am trying to characterise pulsed plasma by Langmuir probe using fixed bias from oscilloscope, but there is one problem.

    At the rising and falling edge of discharge voltage there lies a corresponding delay of 100-200 micro seconds in ion saturation part then it starts decaying decaying, which is unusual. 

    Someone can explain why this is happening?

    Garima Joshi

    Hi....I got the solution

    and I am again attaching ion saturation which contains no  "Glitch".

    The reason for that glitch was improper shielding.


  • Vasanth Krishna Nadella asked a question in Bulk:
    When will a Dirac cone is formed? and how do you differentiate between surface states and bulk states in a band diagram?

    Do Kramer's Theorem explain why Dirac cone is formed.?

  • Olivier Catrice added an answer in Cell Cycle Arrest:
    Could any compound temporarily arrest cells at S-G2 stage?

    Then could be washed off and not (too) toxic to cells.


    Olivier Catrice

    It is rather difficult to give you an answer because there is no identified S/G2 checkpoint on which we could pharmacologicaly act.

    Some drugs act at G2/M checkpoint, some others block cells in metaphase, and some prevent cells from entering in S phase.

    Camptothecin is known to block human cells in (late)S phase, by inhibiting topoisomerase I activity, but it creates many single strand breaks and cells may take several hours before recovering after removing drug or they may enter in a programmed cell death.

  • Robert Rentzsch added an answer in AutoDock Vina:
    Can we turn the internal clustering made by autodock-Vina off. Or can we count the number of cluster in a given bin?

    I am trying to dock ligands with autodock Vina to protein but want to turn-off the internal clustering utility. I have modified this line in the source code:

    const fl out_min_rmsd = 1.0


    const fl out_min_rmsd = 0.0

    and recompiled the code but it seems that this did not work, any suggestion?

    Robert Rentzsch

    I've had the same problem/thought in the past with Vina but it seems it's impossible without major changes to the code, plus the original author has no interest in doing this. The basic advise would be: use the less black boxy and more customizable AutoDock. Not sure if you could contact the folks behind smina, one of several Vina forks. If it's not possible with smina right now, maybe they could make it possible. Certainly they'll have a thorough understanding of the code. Best of luck, Rob

    http://sourceforge.net/projects/smina/ - also see the smina paper

  • Daniele Sasso added an answer in Quantum Physics:
    Why has the classical electron radius generally been rejected in quantum physics?

    There is a very close and accurate agreement between the classical electron radius, alpha, the electron Compton wavelength and the Bohr radius. such that:

    re = alpha. lambdae /2pi = alpha2 a0

    Given the great accuracy ascribed to alpha in particular, this would suggest that the classical electron  radius is valid.  

    Daniele Sasso

    @Jacques Lavau,

    I don't attend usually to this type of applications of electron physics. It seems to me nevertheless the Aharonov-Bohm experiment and the effect, cited by you, is based on the hypothesis that  the magnetic field outside the solenoid is null, but that hypothesis isn't verified correctly in the reality because of the fact that the length of solenoid isn't infinite.

    Dear Andrew, I agree fully with your clarification in regard to Compton's wavelength.

    My regards.

  • Nasim Najjarzadeh added an answer in Filamentous Fungi:
    Does anybody know how can I plot growth curve of filamentous fungi?

    I want to cultivate filamentous fungi in liquid medium containing cellulose as a carbon source and I need to plot its growth curve. But, I don't know what is the best method for it. I will be highly appreciated if anyone can help me.

    Nasim Najjarzadeh

    Thank you very much for your recommendation.


  • Ian Kennedy added an answer in Telecommunications Engineering:
    How to calculate the total number of base station that must be provided?
    I'm wondering how we can decide how many base stations must be built within one area. And, how to assume the required radius of each cell, including the number of subscribers which can be served.
    Ian Kennedy

    @Benny. Yes, and I feel the Erlang equation is an excellent example of how mathematics can help the engineer. My famed definition of an engineer is "someone who can do for a shilling what any fool can do for a pound".

    What a wise investor will do is initially enter the "cream" market, and provide service to the business users, business areas, mobile businesses and major intersections, then progress to the less lucrative markets once capital interest has been mainly paid off.

  • Emmanuel Baranger added an answer in Buckling Analysis:
    How do I include geometric imperfection in a model?

    hello every one 

    i m working on delamination buckling analysis in abaqus 6.14...

    now i want to add geometric imperfection in my model while i m using general static step for buckling analysis ,,,

    can any one help me how i can  add geometric imperfection in my model

    i don't perform eigen value analysis because i dont need different modes and their buckling load..

    i just apply axial displacemnt on two  parts joined by cohesive element with delamination between them....but now i want to add imperfection to it too..i have studied in the abaqus documentation how to add imperfection but that require eigen value analysis,,which i dont want

    i just need to know if there is any other way to add imperfection to my model since i m using general static step..

    thank u

    best regards

    Emmanuel Baranger

    may be I am wrong but I think you have to move your nodes either by using a python script either directly in the inp file.

    best regards

  • Eunice Chin added an answer in Adipokines:
    Could anyone help me in selecting a good commercial ELISA assay to evaluate leptin in rat serum?

    Hello everyone, I need to evaluate leptin levels in the serum of rats in vivo treated with silica nanoparticles. I have difficulties in finding robust commercial ELISA assays to evaluate this and other adipokines (for instance, I tried to measure adiponectin by commercial kits providing pre-coated plates, but it was impossible to have results since the standard curve did not work). Do you have any suggestion based on your experimental experience?

    Thanks in advance.

    Eunice Chin

    I use the ELISA from Crystal Chem in mice (they do have a rat version), which is quite sensitive and works quite well.


  • Pavlo Zolotavin added an answer in Dispersal:
    How can I coat C70 on the cover glass without aggregation or changing the morphology of C70?

    I want to find a solvent that can disperse C70 and easy to be removed. Any suggestions?

    Pavlo Zolotavin


    We use 0.1mM solutions of C60 in toluene to disperse fullerenes for single molecule junctions studies (spin coating on SiO2/Si substrate at 4000rpm). I assume that C70 should be very similar. Toluene evaporates fast and you can get fairly clean surface afterwards. That being said, there are two important remarks. First spin coating creates C60 islands of ~0.5 to 1um in diameter as well as individual molecules on the surface. For truly single molecules you can use thermal sublimation in high vacuum. This is preferred method to get clean, submonolader coverage. You can read about details here http://pubs.acs.org/doi/abs/10.1021/j100195a041

    Hope this helps

  • Huang Yongcan asked a question in Reconstructive:
    I have reconstructed a tree,but I want to reconstruct maximum-likelihood sequences of internal nodes,but I don't know how to do it?

    I have reconstructed a tree,but I want to reconstruct maximum-likelihood sequences of internal nodes,but I don't know how to do it? I sincerely hope you can help me,Thanks!!

  • Aryan Rai added an answer in Dymola:
    How can I overcome the initialization problems when integrating the VLE fluid components (TIL) in DYMOLA to construct a Heat Pump cycle?

    I am using the commercial library TIL to construct a Heat Pump cycle in DYMOLA. When integrating the components to form a closed cycle it fails to start (fails to reduce the DAE index). However when testing the components separately shows no such error. Can anyone help me to know the probable reason for such an error and suggest any method to overcome it.

    Thanks in advance :)   

    Aryan Rai

    Dear Friedrich,

    At present I am using the basic TIL components with some calculated input parameters. Using an appropriate pressure drop model is possible with these components but I doubt if there is any option for mass/energy storage. Plz suggest a method for it. Will update you on status:)


  • Raeesh Muhammad added an answer in Analytical Instruments:
    What will be the best analytical instrument for analyzing ppm level additions in alloys ?

    What will be the best analytical instrument for analyzing ppm level additions in alloys ?

    Raeesh Muhammad

    ICP-MS could be more appropriate for very low concentration.

  • Ivan Dario Gomez Araujo added an answer in Modal Analysis:
    Can anyone help with Matlab for frequency domain decomposition?
    Please help me with the matlab code for FDD in modal analysis. I follow the steps but the part of singular value decomposition of the PSD. I need to develop a structural health monitoring system based on this method
    Ivan Dario Gomez Araujo

    You could use the following function in matlab

    function [Dxy,t]=myrdt(x,y,fs,Med,Nor,Tmax,Case,s12)

    %x=signal 1

    %y=signal 2

    %Med=sides of the RD signature.

     %Med==1 one side

     %Med==2 two sides

    %Nor= Normalization of the random decrement signature.

     %Nor=1 Normalized data

     %nor=2 Not normalized data

    %Tmax = Maximum time of RD

    %Case = 1 Level crossing triggering conditions

       S12=[%percent of max]

    %Case = 2 Local extremum positive conditions

    %Case = 3 Zero crossing triggering conditions

    %Case = 4 Positive point triggering conditions

         S12=[%percent of max , %percent of max]





     if Med==1







    if Case == 4






    for k=np+1:nt-np

      switch Case

      case 1 % Level crossing triggering conditions

          if x(k)>0 

        if (x((k-1),1)<s && x((k),1)>=s)...

                || (x((k-1),1)>s && x((k),1)<=s)





        case 2 % Local extremum positive conditions

            if (x((k-1),1)>0 && x((k),1)>0 && x((k+1),1)>0)

            if (x((k),1)>x((k-1),1) && x((k),1)>x((k+1),1))





      case 3 % Zero crossing triggering conditions

           if (x((k-1),1)<0 && x((k),1)>=0)...

                   || (x((k-1),1)>0 && x((k),1)<=0)




      case 4 % Positive point triggering conditions


            if abs(x((k),1))>=s1 && abs(x((k),1))<=s2

                if x((k),1)>=0









     if Med==1



    [M,N] = size(Dxy);

    mn = mean(Dxy,1);

    Dxy = Dxy - repmat(mn,M,1);

    if Nor==1



  • Tommy Lu asked a question in Sterility:
    Why endothelial cells fall off coverslips upon PBS wash?

    Dear All,

    I am growing my endothelial cells on 1% collagen coated glass coverslips. I noticed that occasionally some of the cells fall off and no longer retain their normal morphology straight after I wash the coverslips with none sterile PBS. I've also tried with sterile PBS but there isn't much difference.

    Will really appreciate any answers.


  • Rachida Es-Salhi asked a question in Clustering:
    What are the suitable image descriptors to perform intra/inter image clustering ?

    Hi community,

    I have a group of related images and I want to perform an intra-image clustering , to find all possible objects in each image, and then an iter-image clustering to determine what are the common segments. But I am confusing in choice of a suitable image descriptor?

    Any help please?

    thanks to all of you.

  • Ajay Tala added an answer in Control Systems Engineering:
    Can Smith Predictor be implemented using analog controllers?

    Which analog control algorithm can be used in Smith Predictor?

    Ajay Tala

    Thanks Yang

  • Valerio Francesco Annese added an answer in EEG Signal Processing:
    I am performing EEG studies on meditation subjects for two sessions-pre and post test. Any advice on calculating power spectral difference in 4 bands?

    Channels : 64

    Pre test and post test comparison (to check the difference in band power before and after the meditation intervention period). I have successfully got the data. But I am confused as how to come up with one value out of the 64 values in order to do statistical analysis. Is mean the right way to do it? If not, please mention several ways that would be helpful.

    Valerio Francesco Annese

    Mainly you can use two different approaches:

    1) Numerically filtering your raw data with 4 filters that you need and than estimate the power in the TIME DOMAIN

    2) Use frequency-analysis tools just like FFT, STFT, Wavelet etc. and than calculate the power in the FREQUENCY DOMAIN coupling the samples of the right indexes according to the band that you need.

    Hope it helps! 

  • Nouran Radwan added an answer in Social Networks and Social Applications:
    How can I get a dataset for social network users?

    I am working in paper and i need user profile data-set including location  or check in dimension in any social network like Facebook. It is to better to be used by previous papers or known datasets. 

    Nouran Radwan

    I need a dataset that is known , also i may extract facebook users data but it couldn't found the check in.

  • Phanor Montoya-Maya asked a question in Time Factors:
    Correct GLMM model for unreplicated factorial design?

    My experimental design is as follows: Three sites (Treatments) that were not replicated (Healthy Control [HC], Untreated [U], and Treated [T]). Six independent measurements (Samples) of a response variable (RV) were taken randomly at each site. The exercise was repeated at two different times (before and after treatment). Thus my dataset looks something like this:

    • SampleID = unique identifier
    • Site: Factor with three levels
    • Time: Factor with two levels Site
    • RV: Count data

    I would like to know if treating the site had an effect on RV. Due to the lack of replicability and correlation between the measurements, I consider running a GLMM. This is where I need some help. I don't know how to build the correct model to test the site effect accounting for the lack of replicability.

    m1 = RV ~ Time + Site + (Time|SampleID))

    Will this model provide a fixed-effects estimate for site that tells you whether site had an effect on RV values?

    m2 = RV ~ Time + Site + Time*Site +(Time|SampleID)

    Will this model provide a fixed-effects estimate for the interaction between change over time and site that tells me whether the rate of change with respect to RV is significantly different between sites? Is this possible to test at all with my data?

  • D. N. Krasikov added an answer in Thin Film Solar Cell:
    What is the average manufacturing time for thin film solar cell at a commercial level?

    What is the average manufacturing time for thin film solar cell at a commercial level?

    D. N. Krasikov

    If you are interested in the complete manufacturing time starting from the manufacturing of glass and preparation of all chemicals, then I do not know the answer. If you are just interested in the manufacturing time provided that the glass and all chemicals are ready, then for CdTe-based modules the answer is 2.5 hours (http://www.firstsolar.com/en/Technologies-and-Capabilities/PV-Modules/First-Solar-Series-3-Black-Module/Manufacturing-Process.aspx). For other types the time may be different.

  • Tania Shakoori added an answer in PCR Primer Design:
    Will real time PCR primers designed for one strain of mouse work on another strain?

    I found primer sequences for checking genetic expression of leptin in Aston strain mice. I was wondering if they would work on tissues harvested from swiss webster mice?

    Tania Shakoori

    Thank you  John, Thomas and David for your very useful feedback. Best Regards

  • Shannon L. Cass-Calay added an answer in Stock Assessment:
    Recommended data-limited stock assessment approaches for invertebrate species?

    What are the most practical data-limited approaches used to assess or manage invertebrate stocks such as lobster and conch when catch rates and age/structure are poorly known?



    Shannon L. Cass-Calay

    Thanks Jeremy, Gilles and Gracias Miguel! I appreciate all you suggestions.


  • Robert Rentzsch added an answer in AutoDock Vina:
    How can I perform in silico molecular docking of a protein with a metal ion?

    Dear RGs, I want to perform docking studies of Gyrase protein (for example: pdb id : 2XCT) which is in complex with ciprofloxacin which is a standard. the protein has manganese as cofactor (can see in the PdbSum link: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl?pdbcode=2xct&template=ligands.html&l=1.1) . Here the ligand ciprofloxacin has covalent bonds with manganese cofactor which plays a crucial role in the protein (http://www.ncbi.nlm.nih.gov/pubmed/12051843).

    I have removed ciprofloxacin from the complex and performed docking again with ciprofloxacin (externally) using AutoDock Vina. The Vina software won't read metal ions hence leading to inappropriate results as in the attached image file. It is forming 1 covalent bond with Ala419 carbon and Oxygen of ciprofloxacin. 

    Kindly provide me some ideas to overcome this problem. suggest some servers or tools where docking can be performed including metal ions.

    Robert Rentzsch

    Adding to the above, please refer to this thread:

  • Sidharta Chatterjee added an answer in Biguanides:
    Dose metformin have no or minimal effect on fasting blood glucose?

    Is the role of Metformin that related to  biguanide class on fasting blood glucose considered as controversial issue ?

    Sidharta Chatterjee

    Actually, Metformin lowers fasting blood glucose without inducing hypoglycaemia. Metformin (Glucophage, Glycomet, ect.) supposedly do not lower fasting blood glucose to a great extent as insulin does, so the risk of fasting hypoglycaemia or lactic acidosis is minimal with its use (contrary to phenformin). Previously, it was assumed that Metformin do not affect lactate metabolism and so does not induce lactic acidosis, but in fact, it may cause minimal lactic acidosis1 which is however, not a great concern. Glycomet also stimulates peripheral uptake and utilization of glucose. 

    Also, metformin strongly interacts with alcohol which can precipitate severe lactic acidosis if taken together. Nevertheless, its effect on controlling the Dawn phenomenon is debated although as a matter of fact metformin supresses hepatic gluconeogenesis (its primary mechanism of action).

    Ref: A simple analysis of metformin's actions are discussed at this site.



  • Vincent Chiang asked a question in SDS-PAGE:
    How to separate 2-5 KDa proteins?

    Does anyone have experiences to separate 2 to 5 KDa protein in SDS-PAGE procedure? Thank you.

  • Raeesh Muhammad added an answer in FTIR Spectrometer:
    Sholud FTIR spectra be taken in either %Transmission or absorbance ?

    Which is better in explanation of FTIR spectra?

    Raeesh Muhammad

    In general FT-IR are reported in % Transmittance but there are reports available where  FT-IR has been reported in % Absorbance also. So it depends in which mode you are more comfortable.

  • Matteo Franca added an answer in Boundary Condition:
    Which is the first eigenvalue of the Laplacian with Dirichlet boundary condition in a ball of any dimension?

    I know that in dimension 1 it is p2/4, but for larger dimensions? Perhaps there is a known formula but also  some estimates could be useful

    Matteo Franca

    I had hoped someone could come out with a nice and simple formula... But this is really helpful! Thank you very much!!

  • Atif Unaldi asked a question in Kenya:
    I am looking for tracking original medicine case in Kenya?

    I am looking for tracking original medicine case in Kenya? Anyone has an information about it? (I think Intel used IoT for tracking) Any link any reseach or case study is welcomed