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

  • Anjusha V S added an answer in Quantum Mechanics:
    Does the interference pattern come back if we repeat this quantum experience by an electron gun than can fire only one electron per moment?

    In other word, only one electron pass to splits per moment

    Anjusha V S · Indian Institute of Science Education and Research, Pune

    Electron can give interference pattern due to wave particle nature , .You can refer Feynman lecture series volume-III where he has given an experimental realization.To observe interference pattern we need to shoot many electron one by one as Aleksei Bykov said.As long as we are not spying the electron it will show wave particle and give interference pattern.

  • Aliakbar Paraj added an answer in Ionic Liquids:
    Is there anyone who known how to measure the concentration of an imidazolium-based ionic liquid diluted in water?

    I am looking for a method regarding the determination of imidazolium-based ionic liquid concentration, after dilution in water.

  • Martin Pohlmann added an answer in Eye Health:
    What are some design principles to guide the design of visual displays to reduce eye strain?

    In designing educational software, I'm concerned about eye health.  What colors are best for backgrounds, and how can we optimize contrast and brightness?

    Martin Pohlmann · Hochschule Magdeburg

    Hi Lance, try this pdf I made ;) I hope it will help you in some. 


  • Kevin Larkin added an answer in Trichotillomania:
    Does anyone know where I can locate the The Milwaukee Inventory for Styles of Trichotillomania-Child Version (MIST-C), and is there a cost attached?
    I need this tool to help me to ascertain a treatment pathway, as it is unclear just via interview to determine the function and aetiology of the hair-pulling at this time.
    Kevin Larkin · Griffith University

    Hi Phillippa,

    You might be able to access it here - not sure if there is a cost involved - other than viewing the article if your library does not have it - http://www.ncbi.nlm.nih.gov/pubmed/17932243 

  • Germán Flor-Blanco added an answer in Zoning:
    Is the coastal dune fixation the same as the fixation of dunes that came after the Sand encroachment in the semi-arid zones? 

    Coastal dunes fixation.

    Germán Flor-Blanco · University of Oviedo

    In the last century normally used pine and eucaliptus in mobile coastal dunes . This practice was exported by French and   there are some examples  in the Iberian Peninsula. However, in Morocco atlantic coast , particularly in Essaouira, they planted Argan (autochthonous tree) and pine, for the dunes didn´t invaded the city.

    Actually in small dune fields or erosive dunes associated to sand barriers in estuary mouths, is planted Ammophila arenaria.

  • Do you support the establishment of industrial plants by a university?

    A university, with a student population of e.g. more than 25,000 & with academic, administrative, and services staff of e.g. more than 2000, consumes lot of papers (despite the existence of electronic displays & versions) and lot of liquid detergents for its laboratories, cafeterias and water closets. If such a university has qualified staff, it can start two medium-scale batch chemical industries to produce what the university needs of these 2 items (papers & liquid detergents).These 2 industries can be made environmentally-friendly.

    Advantages of these 2 industries are enormous. To start with, the university will save money & will train students industrially on the campus.

    Some industries have gained huge profits from universities, but when it comes to supporting  research in academia or accepting students for training in their practical service courses, these industries show negative attitudes. Isn’t it time for the universities to stand up & industrialize part of their activities?

    Mounir Belloumi · Najran University

    Yes, why not? mainly for the engeneering colleges where students can practice their learning.

  • Simon Hutchings added an answer in Time-Series Analysis:
    Interrupted time series analysis using SPSS?

    I am a non-statistician looking to perform ITS analysis on routinely collected prescribing data.  Aside from the guide produced by the Cochrane EPOC group (https://epoc.cochrane.org/sites/epoc.cochrane.org/files/uploads/21%20Interrupted%20time%20series%20analyses%202013%2008%2012.pdf), does anyone know of any online resources to perform this analysis using SPSS?

    Thanks y'all.

    Simon Hutchings · Cardiff University

    Marilyn, Gloriam - thanks very much for your responses. I will take a look at the resources you have provided.

    The routinely collected data is number of prescriptions for a class of medicines per month, for 12 months either side of national guidance being published.  There is no missing data.  Hope this helps?! 

  • Daidu Fan added an answer in Methods:
    Which dating technique is best suited for determining the depositional age of sediments either it is U-Pb method or Ar-Ar and OSL method?

    See above.

    Daidu Fan · Tongji University

    Radiocarbon dating is the best choice for a deposition age of 20~50 kyr 

  • How can we manage the Anxiety, Can Yoga Helps?

    There are several anti-depressive drugs available in the market, is there any anti anxiety drug also? How can we manage the Anxiety, as Yoga therapy  and Counselling are the option, which one is better and safe?

    Béatrice Marianne Ewalds-Kvist · Stockholm University

    According to my understanding yoga is:

    1  a Hindu theistic philosophy teaching the suppression of all activity of body, mind, and will in order that the self may realize its distinction from them and attain liberation
    a system of physical postures, breathing techniques, and meditation derived from Yoga but often practiced independently especially in Western cultures to promote bodily or mental control and well-being

    It then comes down to your culture and belief system.  Anxiety or angst as well as depression is a possibility, un urge, to deepen the understanding of life and to come to terms with not understanding the cosmos and the whole.

  • Are students grade-seeking or competence-seeking?
    Are the students in your program more concerned with developing professional competence or are they focused on getting the points they need to get a grade? Are we doing all we can to foster self-directed learning or do we reward 'load and dump' behavior with honors at graduation?
    Mark E Gould · Education Queensland

    A further point: imagine a system where A is best and E is worst and C is nominally a pass.

    Now imagine you start school a bit behind the 8 ball because your family is low SES and you didn't get read to. As so often i n this case, you are in the lower half of the class in a range of measures because of poor reading skills. So you get a 'D' in a lot of things. Next year you improve at the same rate as the other students but since the pass mark goes up, you still get a 'D'. This is likely to continue because you retain the orignal deficit unless you improve more than the average. After a while you attribute the concept 'failure at school' to yourself and stop trying. This is too common in our schools because of the system. The word failure need never be used but the attribution remains.

  • What SNP genotyping method should I use?

    I want to genotype 300 specific SNPs (spans across multiple chromosomes) in about 600 human patients. What genotyping method should I use?  The DNA is extracted from human blood, and I need very accurate results.

    Please advise. Thank you.

    Daniel W. Förster · Leibniz Institute for Zoo and Wildlife Research

    I'd suggest the Fluidigm nanofluidics platform. We use this for non-invasively collected samples with high success (and v low error rates). 


    This works in a 96 SNP x 96 sample format... Also very fast, and replication is cheap once you have had the assay designed and synthesized.

  • Jeevithan Elango added an answer in Collagen:
    How to brake or degrade the fibrous structure in collagen?
    I am looking to study the degradation of fibrous collagenous structure under control conditions. Can anyone tell me an easy way to break the cross links and triple helix structure in collagen?
    Jeevithan Elango · Shanghai Ocean University

    Heating is a easiest method to break or degrade collagen. The temperature varied based on your desirability (in general 40-90 C) and also your nature of collagen. Some proteolytic enzymes Alcalase, pepsin, collagenase can also be used under opt. conditions. 

  • What are the advantages and what are the problems of the hypothesis about “retinoid system”?
    Is the hypothesis about “retinoid system” (by Professor Arnold Trehub), as described in “Consciousness and Cognition” 16 (2007) 310–330 and in the other works of Professor Trehub, a plausible hypothesis? What are its advantages and what are its problems?

    Professor Trehub describes it in the following words:
    “Activation of the brainʼs putative retinoid system has been proposed as the
    neuronal substrate for our basic sense of being centered within a volumetric
    surround –- our minimal phenomenal consciousness (Trehub 2007). Here, the
    assumed properties of the self-locus within the retinoid model are shown to
    explain recent experimental findings relating to the out-of-body-experience. In
    addition, selective excursion of the heuristic self-locus is able to explain many
    important functions of consciousness, including the effective internal
    representation of a 3D space on the basis of 2D perspective depictions. Our
    sense of self-agency is shown to be a natural product of the role of the heuristic self-locus in the retinoid mechanism.” (Abstract, from: Where am I? Redux.)

    For the publications of Professor Trehub see:

    The question has been already discussed on the folowing thread:
    Eugene F Kislyakov · Belarusian State University

    We are all somebody's (may be God's) patients, Marc. Even if we establish unambiguously correlation between physical events in brain and mental activity, we can not be sure what is the cause of what. Physical event or mental activity?



  • Amira Fakih added an answer in Western Blot:
    Is anyone familiar with western blotting?

    I am using 5% milk for blocking and I want to dilute the primary ab in 3% BSA. Is this Ok or should the blocking solution also contain BSA?

    Second question. Do I have to wash with TBST after blocking or can I add the primary to it directly?

    Suggestions would be appreciated.



    Amira Fakih · Lebanese American University

    prepare the blocking as 5%milk in PBS and add 100micro tween 20...then after blocking overnight to make sure that noise is removed and all nonspecific bindings then put the primary antibody after blocking for 2 hrs on shaker for 25 speed..the antibody is diluted from the milk you already prepared for blocking and add to it PBS.

  • Danilo Bersani added an answer in PPT:
    Why does tio2 ppt become brownish in color when heated in hot air furnace?

    We mixed TTIP with water to form Tio2 ppt then mixed with TMAH solution 62.5:1 molar ratio under 100deg celcius ( under stirring)  then again dryed it into hot air furnace at 250 deg celcius and got brownish color while we should get white powder ..

    Danilo Bersani · Università degli studi di Parma

    Usually the samples I studied were stirred before annealing. There's no way to completely remove organics before annealing.

  • Is PDGF secreted, expressed, or is the signal activated in a normal/cancer breast tissue?
    I'm new in this field and I'd like to learn more about the role of platelet-derived growth factors (PDGFs) in human breast development, function and cancer.
    Jeroen Frijhoff · Maastricht University

    This should get you going.

  • Amira Fakih added an answer in Western Blot:
    Can anyone advise me on my issues with Western Blot?

    I am facing primarily 2 issues with Western Blot. Firstly, during the transfer process, lot of heat is getting generated that results in boiling I do put ice pack during the process, but lately the heat is very high. I run at 100V for 1 hour.

    Secondly, my nitrocellulose membrane is turning pink after the transfer. I have no clue what might be the case.

    Amira Fakih · Lebanese American University

    try to use in the transfer buffer preparation: glycine..tris base ..distelled water and methanol...

    the membrane should be PVDF membrane it will work well

  • chi mai vo added an answer in Anaerobic Bacteria:
    Do we need to add oil additionally in a cooked meat medium (R.C. Medium) to maintain anaerobic condition?
    Or is the media itself enough to maintain anaerobic condition?
    chi mai vo · Ho Chi Minh City Medicine and Pharmacy University

    The fresh or non-inoculated cooked meat medium doesn't need to add oil. But if you want to store some anaerobic isolates, it'd be better to add sterile mineral oil on the surface of the culture.

    I used to maintain some clostridial isolates the mentioned way for at least 3 months with cooked meat medium without sugar, in room temperature.

  • How to explain Photo-luminescence intensity decrease by reducing temperature?

    Normally the PL intensity will increase by reducing temperature. But this time what I got is opposite. Then I measured the material once again and got the same result.

    Can someone  explain that?

    Manuel Schnabel · Fraunhofer Institute for Solar Energy Systems ISE

    Please tell us what you're measuring. Maybe the material undergoes some structural transition in that temperature range. Also, please confirm that the 300K measurement is also done in the cryostat - your changes are not that big and cryostat windows are not 100% transparent.

  • Diaf Mustapha asked a question in Bread:
    Breads Units

    What is the real significance of Breads Units in Diabetic Patients Diet??

  • Nazanin Rahbar added an answer in JCPDS:
    Is there different XRD spectra (JCPDS card) between bulk samples with nanowire?

    Do samples(bulk and nanowire) have same peak in XRD spectra?

    Nazanin Rahbar · Buali Sina University

    thanks for your answer

  • A referendum on full Scotland's independence is in progress. How will the results of this referendum affect the European Union, NATO ...?

    Scotland's independence could bring some reflections to some European regions such as Catalonia, South Tyrol, Flanders, the Basque Country! Even some ideas of ​​new state of Kurdistan can be dangerous, especially for Turkey who would like to become a member of the European Union! What is your concern about, if any?

    Maria Luisa Sanchez-Barrueco · University of Deusto

    From the national perspective, the narrow result of the Scotish referendum sends a warning signal to other independentist movements accross Europe. 

    Both parties at the Scotland issue should learn some lessons from such a narrow result, which means no victory nor defeat of anyone.

    From the EU perspective, institutions should reflect on how to ensure that regions are better taken into account in the decision-making process as a means to improve the EU input legitimacy (government by the people). This should not mean going against the Member States as guardians of the Treaties, but seeking further consistency between the democratic principles the EU promotes beyond its borders and those actually applied within. 

  • David Charles-henri added an answer in Cell Culture:
    What is the importance of TER (trans epithelial resistance) and how to measure it?
    I'm using the millipore TEER electrode to measure the resistance of colon cancer cell line.
    I have been unable to get a stable reading, most of the time it shows fluctuations.

    Although the transwell looks confluent under the microscope the TEER reading is still around 200 only.
    David Charles-henri · Université de Bretagne Occidentale

    I did this for heart vascular endothelial cells (MCEC (Cedarlane/CELLutions Biosystems Inc. ; Ref : CLU510) and as they didn't bind with tight jonction, the TEER was not elevated even when arrived at confluence. 

  • How to score the epithelial section of intestine for immunohistochemistry?

    I am confused with scoring the epithelial sections of intestine because there is the vertical and longitudinal section. Which should I score if both structure exist? 

    Nickolay Fedchenko · ДЗ "Дніпропетровська медична академія"

    Depends on what you want to score and which markers you use. Most IHC studies use semi-quantitative scoring systems which evaluate the "force" of staining (none, weak, moderate, strong) and the prevalence (amount of positively stained cells and\or areas). There are a lot of different approaches. Look for IRS score, for example. 

  • Does anyone have experience with Longitudinal EM waves and the Maxwell equation?

    I have one problem caused by discrepancy between existence of solution for the EM waves (E ~ 1/R) and the Maxwell equation div E = 0 in free space.

    1. There is Jefimenko's wave equation for the E field (i.e. without introduction of the potentials) [J. D. Jackson, Electrodynamics, 3rd ed. p. 246, Eq. 6.49]. Jefimenko showed that his equation gives a solution containing no terms ~ 1/R corresponding to the longitudinal component. All details of his procedure are given in the textbook of Jackson and for example in [K.T. McDonald. Am. J. Phys. v 65, p. 1074 (1997)]
    But Jefimenko considers too arbitrary dependence of the charge (and current) density on r and t,
    \rho = \rho(r,t)
    and the law of the charge conservation requires the dependence
    \rho = \rho(r -r0(t))
    where r0(t) the law of motion of the charge.
    So this law gives some limitation on Jefimenko's procedure and as a result, it should be a solution for the longitudinal component of the E field ~ 1/R (the longitudinal EM waves). I can explain it in detail but one can read my paper on this subject if she/he wishes: Progress In Electromagnetics Research M, Vol. 34, p.73, (2014).

    2. However, it is known that the longitudinal EM waves cannot exist due to the Maxwell equation div E = 0. It is shown by Zommerfeld [A. Sommerfeld, Elektrodynamik. Leipzig: Akad. Verlagsgesellschaft Geest and Portig, p. 36, (1949)]. Despite Zommerfeld presented his proof for the plane EM waves only and such waves don't exist - there is no such a source that is able to radiate these waves - at far distances the spherical EM waves can be treated as the palne waves with good accuracy. So we can accept Zommerfeld's arguments for the spherical waves too.

    Thus I have a cotradictory resulst:
    - there is a solution of the wave equation for E field ~ 1/R
    - this solution is forbidden by the Maxwell equation.

    If someone could advice how to resolve this contradiction?

    Vladimir Onoochin · Sirius, Moscow, Russia

    I should object.
    'Jefimenko's quite general solution are transversal, as you point out'
    Jefimenko's expression may be treated as quite general but if one needs to make calculations until the final stage (to obtain the closed form expressions without integrals or to make numerical estimate the expressions) this person will be obliged to specify the law of motion of the source. So it is hard to assume that this person will ignore the law of the charge conservation while making calculations.

    'The proof of transversality is quite elementary' but it had been made by Lienard in the following order of math operations:
    1. Lorenz's retarded integrals for the potentials are calculated,
    2. The sizes of the source tend to zero,
    3. The E field is computed from the potentials.

    Jefimenko's order of math operations:
    1. The E field is computed from Lorenz's retarded integrals,
    2. The sizes of the source tend to zero,

    Therefore, a question of matter is in the order of the math operations. I think one must go to the limit of zero size of the elementary charge at the final stage of computations. For example, if we go this limit in Lorenz's integrals, we even don't obtain the LW potentials.

    Second argument in favor of Jefimenko's approach.
    The physical quantities in the classical electrodynamics are the fields not potentials. So it mustn't be doubts that the waves of the EM field is physical process (the waves of the potentials is rather imaginary picture). But well know picture of propagation of the EM (transverse) waves by Hertz isn't described by any known differential equation. The wave equation gives isotropic waves. Jefimenko explained why his wave equation gives transverse waves.

    'Follow Sommerfed's reasoning putting your solution inside the proof, and see where things go wrong. '
    I am sorry but it is impossible. Sommerfeld considers the plane waves as postulate.

    I add that my solution is solution of the wave equation but not of the Maxwell equations. It is the problem.

  • Is it possible to measure transistor output and transfer characteristics using Autolab setup?

    I am preparing to start working on thin film transistor (TFT) devices from metal oxides. In literature I have seen most people use semiconductor parameter analyzers for measuring drain current as a function of drain voltage and gate voltage. We do not have this apparatus in our lab, but we have Autolab PGSTAT30/2 setup that we use for  solar cell IV and Impedance/admittance spectroscopy measurements.
    I was wondering if it is possible to use this Autolab to characterize TFT devices.

  • How to calculate the limited integration for the function {(sqrt(sin(x))/(sqrt(sin(x)+sqrt(cos(x))} from x1=0 to x2=pi/2?
    Do not use the integration by parts.
    Harish Kumar Kotapally · Indian Institute of Technology Indore

    Sir, Check out the answer in the following link 

  • Lampros Zouloumis added an answer in Implants:
    How to take impression when two implants are placed too close together?

    four implants have osseointegrated well., but are too close to place impression posts

    any suggestions to make good impressions 

    Lampros Zouloumis · Aristotle University of Thessaloniki


  • Dirk Rattat added an answer in Literature Search:
    Can someone suggest any references for 'Methods and Efficiency of Adult Education in the French Republic'?
    Study conducted at Warwick University. Looking for documents in the French Language
    Dirk Rattat · Umicore

    Maybe "Development of cognitive abilities during training" (E. Loarer et al.) and cited references?

    TRAVAIL HUMAIN, Volume 61, Issue 1, 51-67