Q&A

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

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • Gopal Singh added an answer in Glass Transition:
    Can the crystalline materials show glass transition temperature?

    My organic sample is giving sharp peaks in XRD but still glass transition temperature around 250C has been observed. Usually crystalline materials do not show glass transition temperature. (file attached)

    Any suggestions 

    Gopal Singh · Guru Nanak Dev University

    thank you Dr. Zhang and Dr. Wang

  • Which topics in the field of mechanical engineering will be more on demand both in academic and industry in next five years?

    I am leading a research group including several graduate and undergraduate students in the field of multidisciplinary design optimization of mechanical structures and therefore always looking for new ideas and collaborations. Play always win-win game.

    Omid Majidi · Pohang University of Science and Technology

    In academic topics, the virtual field method and its application is growing fast. In automotive industry, hot stamping of high strength steels is getting popular. New intelligent forming technology will open new doors.

  • Ishag Adam added an answer in Splenomegaly:
    Has anyone found treatment guidelines for Hyperreactive Malaria Splenomegaly Syndrome?

    Reviewing literature for a research paper, but unable to find any specifics on effective treatment regimens or duration. Reports of high relapse rate and limited data regarding specific anti-malarial treatment efficacy. In addition, multiple references to "unascertained" treatment duration and attempting to better construct treatment algorithm or guidelines.

    Ishag Adam · University of Khartoum

    Dear  Matthew Goers

    This is a big problem  facing.  I think  it is by  old  treatment of malaria for long  period

  • S. Khoirul Himmi asked a question in Termites:
    Is it possible that drywood termite use chemicals on fecal pellets for intra-colony communications?

    As individuals of drywood termite colony are distributed on different position inside nest-gallery, how they "attract" nest-mate or inform their presence in certain chambers?

  • Prabhakar Purushothaman asked a question in Adoption:
    What are the changes you want to see in life?

    Change is unstoppable everything everywhere in world changes weather we like or not we used to adopt it in terms of technology, habits, our daily actives etc many changes helped us like mobile phones, bullet trains, Internet etc at the same time many changes harmed us like Pollution, global warming etc In our short life we adopt to so many changes kindly share your ideas of various changes you want to see in life

  • Aibek Smagul added an answer in LC-MS:
    Is anyone familiar with MTX determination in RBC with ESI LC-MS?

    Hello, everybody!

    Can you help me with Agilent 1260 and 6224 mass-spec. I'm using the many methods for sample preparation for eluate the MTX from blood cells, but my tries don't give me results?

    I'm use the 1mM ammonium formiate+ 0,1% Formic acid (75) and ACN 25 to mobile phase, and prepare the samples with Perchloric acid 16%, QC with 100ng and 1000ng don't shown after sample prep.  What is the reason?

    Aibek Smagul · Kazakh National Medical University


    Unfortunately, we have blood was stored at -20 ° C and more than 2 months. I have tried many methods to allocate MTX but all to no avail. I think to try to extract pereobrozovanny MTX using 200 mM ascorbic method (Determination of erythrocyte methotrexate polyglutamates by liquid
    chromatography / tandem mass spectrometry after low-dose methotrexate
    therapy in Chinese patients with rheumatoid arthritis
    Xiaolan Moa, d, Yuguan Wenb, Bin Rena, Jie Chena, Chenshu Xua, Xueding Wangc, Min Huangc,
    Xiao Chena, *). anyone ever had this experience with the samples?

    Thanks for the assistance!

  • Can you give me suggestions on cointergration and error correction models? Why are these models used and what are their advantages?

    Thanks in advance for your replies.

    Tantatape Brahmasrene · Purdue University North Central

    A vector error correction (VEC) model is designed for use with nonstationary series that are known to be cointegrated. Engle and Granger (1987) pointed out that a linear combination of two or more non-stationary series may be stationary. If such a stationary, or I(0), linear combination exists, the non-stationary (with a unit root), time series are said to be cointegrated. Please check below for ex-im model.

    https://www.researchgate.net/publication/271076688_An_Analysis_of_the_Determinants_of_Thailand%27s_Exports_and_Imports_with_Major_Trading_Partners

  • Shama Parveen added an answer in Fermi Level:
    Are Fermi level and Band gap same?

    I need to know about the fermi level and band gap in semiconductor materials?

    Shama Parveen · Jamia Millia Islamia

    No,

    Fermi level is highest occupied energy level at zero temperature while band gap isthe difference between valence band and conduction band. 

    thanks

  • Dr. Nizar Matar added an answer in Socioeconomics:
    How a nation can achieve a sustainable socio-economic development?

    SDGs will replace MDGs after 2015. In your views, what are factors or conditions for a nation to achieve a sustainable socio-economic development? Is it a rich culture, literature, technology, tolerance, ethics, or else? And how?

    Dr. Nizar Matar · An-Najah National University

    I have been invited by Professor Pahlaj Moolio to re-participate in this thread few hours ago. I did that on page 2 of this thread. Besides the valuable 127 contributions by RG colleagues, I must stress that sustainable socio-economic development of a nation requires firstly a good leadership. The ordinary people cannot be initiators for such development but their capabilities can be utilized within a process supervised by those who "lead" in the real sense of the word.

  • Whether organically grown crops really have good quality parameters?

    I am asking this question because even though when we apply organic manures to plants it takes in inorganic form itself. Then in what way is the quality going to improve? If anybody have information pertaining to improvement in quality parameters  please discuss.

  • Which are the limitations of non-invasive prenatal diagnosis using Fetal Cells Circulating in Maternal Blood?

    Fetal cells circulating in the peripheral blood of preg-
    nant women are a potential target for noninvasive
    genetic analyses. They include epithelial (trophoblas-
    tic) cells, which are larger than peripheral blood leu-
    kocytes. 

    Ishag Adam · University of Khartoum

    Thanks luis

  • Shaira Narido added an answer in VASP:
    How do you make VASP calculations faster?

    I saw that there are many ways to make VASP calculations faster. I have some questions regarding these methods.

    (1)Set ALGO=F. Basically, this uses Blocked Davidson algorithm in the first five steps and uses RMM-DIIS. Question: Is this safe to be used? I read from a tutorial handout that RMM-DIIS can skip some of the eigenstates.  I am not sure what that mean though.

    (2)Set LREAL=A I heard this will affect accuracy. How will I know if the accuracy effect is not acceptable? Is there some convergence/benchmarking tests like for ENCUT and kpoints to see if its effect on accuracy is unacceptable?

    (3) Use NSIM = 4. I haven't read much about this. Any experience on using this option?

    (4) Use mixing tags. How do you know how to play around and set the values of IMIX, INIMIX, MAXMIX, AMIX, BMIX, AMIX MAG, BMIX MAG, AMIN, MIXPRE, and WC tags?

    Thank you very much,

    Shaira Narido · De La Salle University

    Thanks for the answers!

  • Chander Prakash added an answer in Reaction Force:
    How to study the interface strength using cohesive zome modeling?

    I want to study the interface strength under tension and shear using cohesive zone modeling. To simulate this process the bottom part of the model (metal) was fixed, while the Upper part of the model was displaced with an incremental displacement in the tension or shear direction, while monitoring the reaction force of the top bone nodes. The models were loaded until failure.
    To simulate this bonding, Exponential Cohesive Zone elements were defined at the connections between the material-1 and material-2 components of each model. Input properties for the Cohesive Zone elements were chosen empirically so that an equivalent applied stress of 0.5 MPa (in tension) and 5 MPa (in shear) led to interface failure; briefly, a simulated 2 x 2 x 2 mm3 block of material was modeled with faces aligned with the program’s global Cartesian axes (X, Y, Z), and was then divided into two 2 x 2 x 1 mm3 halves. One half-block (from Z = 0 to Z = 1 mm) was assigned the material properties of material-1 while the other half block (from Z = 1 to Z = 2 mm) was assigned the material properties of material-2. The half-blocks were meshed with SOLID187 quadratic elements using the program’s Smart- Size functionality, and INTER204 Cohesive Zone elements were created at the interface between the two halves. Then, the Ti nodes at Z = 0 were constrained from moving in any direction, while a multipoint constraint was applied to the bottam part nodes at Z = 2 mm such that they would always have equal displacements in the Z-direction. Displacements were then applied to the nodes at Z = 2 mm to create either tensile or shear stresses at the material-1/material-2 interface, and a solution for the model was found.

    In, this simulation: when I apply any value of displacement (e.g. 1 mm), it will give error.
    Please tell me where I am giving wrong inputs in this code and also suggest how dynamic displacement give.
    APDL Code:
    /PREP7 ! Preprocessor
    ! Defining geometry
    BLOCK,,2,,2,,1
    BLOCK,,2,0,2,0,-1,
    kwpave,1,2,3,4 ! Align working plane with keypoints
    ET,1,SOLID185 ! Define solid element
    et,2,205 ! Define interface element
    ! Defining material properties of material-1 and material-2
    ….
    ! Select volume number 2 and mesh with Ti material properties
    ……………
    ! Defining interface element at the interface of the two blocks with interface material properties defined earlier
    NSEL,S,LOC,z,0
    NUMMRG,NODES
    CSWPLA,11,0,,,
    TB,CZM,3,,,EXPO ! Defining interface material properties
    TBDATA,1,0.5,,-5,,
    TYPE,2
    MAT,3
    CZMESH,,,11,Z,0,
    alls
    csys,0
    gplot

    ! Fixing all the nodes at area at z=-1 in z direction
    asel,s,loc,z,-1
    aplot
    nsla,s,1
    nplot
    d,all,uz,0
    sbct
    alls
    gplot
    ! Coupling all the nodes at z=1 to have same uz value
    asel,s,loc,z,1
    aplot
    nsla,s,1
    nplot
    cp,1,uz,all
    alls
    gplot
    FINISH
    /SOL
    FLST,2,1,1,ORDE,1
    FITEM,2,5293
    !*
    /GO
    D,P51X, ,0.05, , , ,UZ, , , , ,
    /STATUS,SOLU
    SOLVE

    Chander Prakash · Panjab University

    Yes, I have solved 2d and 3d model using cohesive zone modeling.

    I have  assigned material properties of interface (Exponential). Plz see above code.

  • Muhammad Salili added an answer in SH-SY5Y:
    Can someone suggest an automated software to measure neurite outgrowth?

    I would like to measure neurite outgrowth in SH-SY5Y cells. Can someone suggest me a best automated software to measure neurite outgrowth? I have tried NeuroJ - Image J plugin but it is a semi automated one. I will have many different conditions, so automated software would be best for me.

    Thanks

    Muhammad Salili · Kent State University

    I suggest you to use Tracker software which is an open source program (free). It is really good for video analysis, mostly when something moves. You'd be able to download it from https://www.cabrillo.edu/~dbrown/tracker/

  • Venkatesan Rv asked a question in Quantization:
    How to implement vector quantization and UBM-GMM by utilizing the MFCC and RASTAPLP features

    I have extracted MFCC and RASTAPLP features i am trying to use vector quantization or UBM-GMM  for text independent speaker recognition please suggest some link to implement this ?.

  • Jaime Marian added an answer in Iron Compounds:
    What is the most recent modeling research on copper precipitation in binary Fe-Cu alloys?

    I need to calculate size distribution of copper precipitates in an Fe-Cu alloy during thermal aging. I am starting off with the cluster dynamics model of Mathon et al (J Nuclear Mat, 1997). is there any updated model?

    Jaime Marian · University of California, Los Angeles

    Hi Jeon-Yin,

    there are more recent papers that have approached the issue from a modeling point of view. I recommend that you look up the work of Frederic Soisson using Monte Carlo simulations as a starter.

    Jaime

  • Muhammad Salili added an answer in MATLAB:
    How to calculate the movement of bacteria or any protozoan using MATLAB?

    There are few opensource and MATLAB is also providing materials to study the movement of bacteria from one place to another. 

    But is not really working with my samples (video).

    is there any software or code for MATLAB , so that we can estimate the movement and speed of the moving organisms

    Muhammad Salili · Kent State University

    I suggest you to use Tracker software which is an open source program (free). It is really good for video analysis, mostly when something moves. You'd be able to download it from https://www.cabrillo.edu/~dbrown/tracker/

  • Can you induce type 1 diabetes in NOD.Scid by transfer of naive CD4 T cells from heathy NOD?

    I was wondering if the transfer of naive CD4 T cells (from a heathy NOD mouse) into an NOD.Scid can induce type 1 diabetes. Or, does it require that I transfer the naive CD4 Tcells alongside antigen presenting cells into the NOD.Scid?

    Ercument Dirice · Joslin Diabetes Center

    I agree with Daniel. Studies mainly discuss that CD4 and CD8 T cell act together. Total lymphocyte (spleenocyte) injection from new onset of diabetic or established diabetic NOD to NOD.RAG or NOD.Scid mice results with adoptive transfer of diabetes (4 to 6 weeks). If you deplete (in vitro or in vivo, separately or together) CD4 and/or CD8 T cell you can see that adoptive transfer does not work. It is also reflected in the pancreatic sections of the recipient immunodeficient mice. HE staining shows, no or minimal islet infiltration. We have a recent paper with these immune cell depletion studies on beta cell proliferation.

    Soluble factors secreted by T cells promote β-cell proliferation

    http://www.ncbi.nlm.nih.gov/pubmed/24089508

  • Tang Suye added an answer in Thermodynamics:
    Why the equation of the first law contains a negative definite function?

    For the first law

    dU=TdS-pdV+ΣμdN.

    According to the physical meaning of the internal energy, U represents the total energy within the system, so should be expressed as the sum of the different types of energy within the system, whereas, if we consider an integral equation, for Euler equation

    U=TS-pV+ΣμN.

    Since p and V are the two positive definite variables, so –pV is a negative definite function. Therefore that, the mathematical form of Euler equation conflict with the physical meaning of the internal energy.

    For instance, for a photon gas, the integral of –pdV is less than zero. Helmholtz free energy

    F=-pV=-U/3.

    Where F is a negative definite function, so F cannot be explained as a part of the internal energy, then what it is?

    I have my own answer for this question, but want to know what your opinion is.

    Tang Suye · Independent Researcher

    Dear Aleksei

    For

    S=N(ln(V/N)+1+i/2*(lnT+ln(C)+1))

    Where is μ?

  • Why does the ability of bacteria to degrade organic matter weaken over time?

    I isolated one specie of bacteria from mixed culture and used it for the degradation of organic matters. For the first and second batch of experiments, it works very well on the degradation of the organic matter. For example, the degradation efficiency of 100 mg/L organic matter could be 90-95%. However, after I stored the bacteria in the -80°C after a period of time, and used it to grow in the media at 25°C. After inoculated in the reactor, it did not work very well. Under the same condition, it could only degrade about 50% of organic matter in 3 days. It happened twice for my research. Does anyone have any idea about it? Why the degradation ability of the bacteria is not as good as before? Thank you 

    Prakash Mallappa Munnoli · S D M College of Engineering and Technology

    let me know why did you store it at -80°C

    for optimization what temperature is required

    Give me period in which your bacteria is in exponential stage

    Regards

  • Maulik Rachh added an answer in MaxQuant:
    MS/MS free software for protein identification?

    Hi everyone, im looking for a free software to analyze MS/MS raw data and try to do protein identification. Any recommendation?? Im currently using MaxQuant but there aren't tutorials or user guides for this software, so its difficult to understand some information about it (beginners)

    Thanks a lot! 

    Maulik Rachh · Veer Narmad South Gujarat University

    Check this link

  • Andrew Messing added an answer in Hand:
    Why does limit of function not exist when its right hand limit and left hand limit are differents?

    If right hand limit and left hand limit exist, that means the limit 'exists'.

    But, this is wrong.... Why??

    Even in complex case, lim (z->0), (x^2y)/(x^4+y^2) does not exist... coz depending on the path, the values of limit changes.

    Why does that mean the limit does not exist?

    Andrew Messing · Harvard University

    "For every real ε > 0, there exists a real δ > 0 such that for all real x, 0 < | x − p | < δ implies | f(x) − L | < ε. "

    To expand on this in a way is how I think more texts should immediately start after introducing he above is the "limit definition", lets examine this idea of having a different right-hand and left-hand limit.

    Suppose that as x approaches a our function approaches R, the right hand limit, AND IT ALSO approaches L, the left-hand limit as x approaches a from the other direction. Using the limit definition, that means that for the right-hand limit R there must exist a δ1 such that for all x, if  0<|x-a|<δ1, then |f(x)-R| < ε. In other words, for R to be a limit, it has to satisfy the definition.

    Likewise, there must be a δ2 such that for all x, if  0<|x-a|<δ2 then |f(x)-L| < ε.

    However, the limit definition demands we have a δ such that this:

    (1) for all x, if  0<|x-a|<δ, then  |f(x)-R| < ε AND  |f(x)-L| < ε

    or that both the right-hand limit R and the left-hand limit L satisfy the limit definition. So we take the minimum (δ12) and let δ equal that minimum. Now we can see if it is possible for (1) to be true. We've got our δ, so now we look for a good ε. Since we are asserting that (1) holds true for two different limit values R & L, we can set ε = |R-L| /2 or the difference between the two limit values dived by 2 (as the difference must be positive, because R is not equal to L). so now we have for all x

    (2) if  0<|x-a|<δ, then  |f(x)-R| < |R-L| /2

    AND

     |f(x)-R| < |R-L| /2

    If there can be a right-hand and left-hand limit that have different values but the limit exists, then (2) should be true, as the limit definition requires that for ALL ε>0, we find a δ>0 as in (2). But (2) CAN'T be true, for if  0<|x-a|<δ then

    (3)  |R-L|= | R- f(x) + f(x) - L | <= | R- f(x)| + |f(x) - L | < |R-L| /2 + |R-L| /2 = |R -L|

    It's kind of hard to see given the make-shift math symbols and font, but the above says that |R-L| is less than something it is equal to, a blatant contradiction. Therefore, it cannot be that there exists any two limits R & L unless R=L.

    I am generally of the opinion that speaking of right-hand or left-hand limits isn't very helpful to understanding limits but can quite easily make things more difficult, as the moment one is talking about limits in higher dimensions there's not really any analogue, just ways in which thinking about a function approaching from only two directions can lead you astray. Generally, calculus classes rely on a lot of pre-calculus mathematics so that the more difficult calculus concepts can handled by learning a bunch of rules. The limit definition perfectly supplied by Weiguo Xie can be quite conceptually challenging, so often enough little time is spent using it and that little time involves doing practice problems that don't really help you understand what limits are (most of the "big name" calculus textbooks have few if any problem sets that include ε-δ proofs, one of the few kinds of problems that can really help one understand the nuances of limits). However, all of calculus and analysis are built upon them.

  • What is meaning of X in ISSN number?

    Some journals have ISSN number ending with X. What does it mean? Any insights?

    Behrouz Ahmadi-Nedushan · University of Yazd

    An ISSN is composed of eight digits: the arabic numerals 0 to 9, except that in the case of the last digit, which is a check digit, the upper case X can appear. The purpose of the check digit is to guard against errors caused by the incorrect transcription of the ISSN. The method of determining the check digit for the ISSN is the modulus 11 basis, using the weighting factors 8 to 2. In the case of the ISSN, the Roman numeral X is used where the check digit calculation results in a remainder of 10.

    The above is taken from Library of Congress

    There is also a wikipedia page which can be referred for further info

  • Abdullah Alnuqaydan asked a question in Wellness:
    Can anyone please help to find out how we can calculate the cloning efficiency (CE) of Petri dishes instead of plates for HPRT Mutation assay?

    Please Note: To calculate the cloning efficiency (CE) of plates I follow the formula below:

    CE= (In number of negative wells/total wells scored)/ number of cells plated per well)

    Calculate of Mutation Frequency (MF)

    MF= CE+6-TG/CE-6-TG

    Thanks

  • Okechukwu Ikeanyibe added an answer in Policy:
    What are the determinants factors of policy implementation?

    Factors determine policy implementation

    Okechukwu Ikeanyibe · University of Nigeria

    these could be daunting, ranging from resource availability, expertise of those implementing, political will, transparency and accountability to issues of opposition from those who do not like the  policy

  • When you have publihed first research paper in your life?

    i want to ask you at what age and designation you have published your life first research paper in conference. This question is very helpful to me for my research survey.

    Dr.Thiyaneswaran Balashanmugam · Sona College of Technology

    In the year of 2007, during PG degree

  • S. T. Patil added an answer in Simulation Modeling:
    What are the best tools for simulation and modelling?

    Hi,

    I wanted to know what are good tools for simulation and modelling and does it really need a tool? Can't we build our own software for out own system?

    I am new to this field only thing I know is there are two parts is such system 1) mathematical modelling 2) Graphical representation ( Its my perception need not be true).

    So can I implement mathematical modelling  using any object oriented language on my own and for graphical part  can use some tool to reduce efforts and time.

    Also suggest me some material that must be required to enter into field of simulation and modelling.

    Thank you.

    S. T. Patil · Vishwakarma Institute of Technology

    following are the different tools for different research area and applications;

    ASCEND - open source equation-based modelling environment.
    DWSIM - An open-source CAPE-OPEN compliant chemical process simulator.
    Elmer - An open source multiphysical simulation software for Windows/Mac/Linux.
    Facsimile - a free, open-source discrete-event simulation library.
    Freemat - a free environment for rapid engineering and scientific prototyping and data processing.
    Galatea - A multi-agent, multi-programming language, simulation platform.
    GNU Octave - An Open Source mathematical modeling and simulation software very similar to MATLAB.
    Minsky (economic simulator) - an open source visual computer program for dynamic simulation of economic models.
    ns-3 - a popular Open Source network simulator.
    Mobility Testbed - an Open Source multi-agent simulation testbed for transport coordination algorithms.
    OpenFOAM - an open-source used for Computational Fluid Dynamics (or CFD)
    OpenEaagles - multi-platform simulation framework targeted to help simulation engineers and software developers rapidly prototype and build robust, scalable, virtual, constructive, stand-alone, and distributed simulation applications.
    Open Source Physics - An expansive, open-source Java software project for teaching and studying physics. It contains packages for drawing and plotting, solving differential equations, exporting to animated GIFs and movies, simulations, and much more.
    Physics Abstraction Layer - an open source physics simulation package.
    Sage - System for Algebra and Geometry Experimentation via Python.
    Scilab - Free Open Source Software for Numerical Computation & Simulation similar to matlab
    SimPy - an open-source discrete-event simulation package based on Python.
    Stanford University Unstructured - an open-source used for Computational Fluid Dynamics simulation and Optimal Shape Design
    Step - an open source two-dimensional physics simulation engine (KDE)
    Tortuga - An open source software framework for discrete-event simulation in Java.

  • Victor C. Kok added an answer in Vitamin D:
    What are the main polymorphisms in the vitamin D receptor gene?

    Polymorphism may affect vitamin D level in the serum.

    Victor C. Kok · Asia University

    Hi, Manar, KIM KÖSTNER et al have published a very nice article on the relevance of various VDR gene polymorphisms for cancer in the journal Anticancer Research.

  • If an abstract of a piece of research was presented at a meeting does that mean that the research has been carried out?
    I am specifically looking for a the research paper that goes with this: Incidence of gastro-οesophageal reflux after two different fasting times: a survey in dogs undergoing ovariohysterectomy. It was delivered in 2010 to a meeting of Veterinary Anaesthetists
    Jennifer Carter · University of Melbourne

    As abstracts are often presented at meetings prior to the acceptance of the research paper by a journal, it is possible for an abstract to be presented and have no corresponding journal article.

  • Maulik Rachh added an answer in Primer Sequences:
    A *working* murine TLR6 primer for qPCR?

    Is there a qPCR primer sequence that is known to be *specific* to murine TLR6 that anyone has used before?  I've been struggling to find a sequence for several months now that yields good Cts and is actually specific to TLR6.

    Maulik Rachh · Veer Narmad South Gujarat University

    You can try this primers

    mTLR6 RT-Primers
    TLR6 RT-PCR primers to determine murine TLR6 expression (Invivogen)

    http://www.invivogen.com/PDF/mTLR6_RT-Primers_TDS.pdf