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  • Jing-Zhe Jiang asked a question in Negative Staining:
    How to prove the surface of a DNA-protein complex is covered by DNA or Protein?

    I have a spherical dsDNA-protein complex, which diameter is about 30nm under negative staining in EM. We suspect it was covered by dsDNA instead of protein because the contrast of its image is not as clear as typic protein structure under negative staining. However, the dsDNA of the complex can resist the degradation of DNase I. If I want to prove the surface of a DNA-protein complex is covered by DNA or Protein, is there any other methods to use?

    Thank you!

  • Sarah Dsane added an answer in Education:
    What would you prefer: daughter’s higher education or son’s higher education? And why?

    In an extreme case and in some parts of the world it can be a real case, if parents have financial capacity to send only ONE of their two children to school for a higher education - they have one son and one daughter. In your view, which one should they prefer to send to school for higher education? Their son or daughter? And why?

    Sarah Dsane · National Film and Television Institute

    If a daughter seems brilliant and can cope with academic work better than a son I would prefer to send a daughter. This is because for me we all have our fields of excellence and if a son will do better in art and can perform better by understudying someone high school and be able make it in life without attending a university so much the better for him..  

  • Varun Penmatsa asked a question in Structural Testing:
    Residue when etching SiO2 using CF4 plasma?

    I am trying to etch 3um vias through 300nm SiO2 using CF4 plasma. These vias connect top ITO layer with bottom metal layer. After CF4 etching, I am able to confirm through the 500um circular vias test structures that SiO2 is completely etched but am unable to get electrical connection through the 3um vias (I have separate test structure to test the connectivity between the two metal layers). I am guessing there might be some hydrocarbon residue from the CF4 etching. Please provide suggestions/ comments on how to solve the problem. I do a low power O2 plasma etching to remove residual photoresist.

  • Suzy J. Styles asked a question in Phonetic Analysis:
    Acoustic analysis of speech - recommendations for lapel mics?

    I am planning a series of 'field recordings' of speech. An individual speaker per recording - to be conducted in 'a quiet indoor space'. Planned analyses include format tracking (F0-3).

    Researchers in the field of acoustic/phonetic analysis of speech: What lapel mics do you use? What are your experiences with different models? Do you have recommendations for particular models currently available? Would prefer an economical solution (for multi-site testing), but open to suggestions.


    Suzy Styles

  • Harshad Surdi asked a question in Heat Transfer:
    Time dependent heat transfer in COMSOL

    I am performing a joule heating with time dependent heat transfer. I have selected the "Heat Source" and "Temperature" boundary conditions and performing a time dependent study. However I am getting a temperature which remains constant for all the time steps. This remains the case no matter how small I give my time step.

  • Reginald L. Bell added an answer in Regulations:
    Should academic promotions have a minimum time requirement?

    Full-time academic staff is eligible for promotion if they fulfill all eligibility requirements for promotion. Promotion regulations differ from a university to another. What is the time requirement in your university? What is your opinion about the minimum time requirement?

    Reginald L. Bell · Prairie View A&M University

    Post-tenure review resolves this problem at my institution.

  • Yang Wang added an answer in Data Processing:
    Tools for quality control and filtering data in processing RNAseq data - any thoughts?

    I have the pair-end RNAseq data, and before doing the follow work with tophat, cufflinks, or other softwares, it's necessary to filter the data. Do you have any good recommended tools for quality control and filtering data?

    Yang Wang · Nanjing Agricultural University

    Thanks a lot, Beryl, I will try that

  • Indrikis Krams added an answer in Ethovision:
    Is Noldus EthoVision XT the best method to track body movements in Drosophila flies?

    EthoVision is software by the company Noldus.

    Is anybody aware of anything better?

    Indrikis Krams · University of Tennessee

    Have anybody ever tried to use the behavioral sequences obtained by EthoVision, SwissTrack or other software to see whether these are described by Markov chains or by non-Markovian dynamics?

  • Holger Wille added an answer in Scrapie:
    Is anyone acquainted with axon degeneration in Prion related diseases or any other neurodegenerative diseases in Vitro?

    In my lab we working on Prp scrapie 106-126 amino acid sequence.

    Holger Wille · University of Alberta

    Indeed, not too much work on that particular question.

    Do you know this paper:

    Sublethal concentrations of prion peptide PrP106-126 or the amyloid beta peptide of Alzheimer's disease activates expression of proapoptotic markers in primary cortical neurons.
    White AR, Guirguis R, Brazier MW, Jobling MF, Hill AF, Beyreuther K, Barrow CJ, Masters CL, Collins SJ, Cappai R.
    Neurobiol Dis. 2001 Apr;8(2):299-316.

    It's as close as I could find it.

  • Shaobin Zhu added an answer in Trehalose:
    Measurement of particle size by dinamic light scattering, laser diffractometry and TEM

    I have measured some particles I prepared by different techniques, and I have obtained very different results with each one. They are around 1500 nm when used laser diffractometry, 500 nm when I used DLS, and tiny (aroun 30nm but very very polydisperse) when I visualized them under TEM. They had trehalose for cryopreservation. Can anyone find an explanation for this? What data should I trust?

    Thank you!

    Shaobin Zhu · University of Iowa

    The principle of DLS is Rayleigh scattering,which falls off with the sixth power of particle size. So when the sample is polydisperse or easy aggregated. The large particles in the solution would be more influence to result, even a very small proportion of the sample.

  • Has someone already registered a water electrolysis with a high speed camera?

    One of my project is to register with a hispeed camera the start of the water electrolysis with plates or foams to determine where the electrolysis occurs.

    Maddali V S Murali Krishna · Chaitanya Bharathi Institute of Technology

    An optically transparent polymer electrolyte membrane (PEM) water electrolysis cell was studied using a high-speed camera, thermal imaging and electrochemical impedance spectroscopy to examine the relationship between flow and electrochemical performance. The flow regime spans bubble and slug flow, depending on the rate of gas formation (current density) and water feed rate. Electrochemical impedance spectroscopy (EIS) shows that there is a reduction in mass transport limitation associated with the transition to slug flow.

    Absract from In situ diagnostic techniques for characterisation of polymer electrolyte membrane water electrolysers – Flow visualisation and electrochemical impedance spectroscopy
    I. Dedigamaa, P. Angelia, K. Ayersb, J.B. Robinsona, P.R. Shearinga, D. Tsaoulidisa, D.J.L. Bretta, , International Jounal of Hydrogen Energy, 39(9), 2014, 4468-4482

  • Laith A. Jawad asked a question in Cyprinidae:
    Question on fish otolith

    Hi All

    I have a question and I would like to know the answer from the interested people.

    We are all know that in fish head there are three sets of otolith called, Sagitta, Asteriscus and lapillus. In all teleosts except the members of the families Cyprinidae and Siluridae, Sagitta is the largest and carry an ornamentation on its surface. In Cyprinidae, Sagitta is the very small and Asteriscus is the largest, while in Siluridae, Lapilus is the largest.
    Could anybody explain to me why such differences occur?


    Laith A. Jawad

  • Vasily Shinin added an answer in Serum:
    What do you suggest as a good blocking buffer for immunofluorescence in parafin embedded formalin fixed lung tissues?

    I've seen anywhere from 1% BSA to 10 BSA, calf serum, and horse serum, with or without fish skin gelatin.

    To reduce background all solutions (blocking and subsequent incubation steps) can be done in  TBS instead of PBS. Critical steps are: duration of fixation, quality of fixation. and retrieval method. Serum for blocking should be IHC-grade and the same species as your secondary abs. Blocking is done overnight at 4C  or at least 2h RT (20C). I use 10-20% Donkey serum in TBS

  • Can I test significant difference between Independant categorical variables?

    I have obtained a result, number of Gram+ve  and Gram-ve bacteria isolated from table eggs. My first question is can I conduct a test to measure significant difference between mean of the two variables. The second question is whether it should be a parametric or nonparametric test, and what type of measure should I use? 

    Currently I am using SPSS and I have input my data in one categorical variable in which 1 represent Gram+ve and 2 represent Gram-ve, was inputing the data right? 

    Jeremy Brooks · Griffith University

    Hi Mohammed,

    I have assumed you are treating eggs as groups (this would be the easiest way to do it)

    For two eggs: You first need to assess the normality using skewness and kurtosis in order to choose a parametric or non-parametric statistical test. If your variables (Gram -ve and Gram +ve) are computed within -3 and +3 for these two tests, then you data is normal and you can proceed with a parametric test. The best way to determine if there is a sig difference in the means of the two groups is using an independent samples T-test. You have to ensure your data is normally distributed (as described above), ratio level data, that the two data sets are observed independently (i.e. they are not paired in any way), remove any outliers that you can see (you can do this by examining the range by summarising your groups with descriptive methods), and assess the homogeneity of variance within both groups using Levene's statistic (ensuring the resultant p-value is not less than 0.05). Before conducting your T-test, split the file based on Gram +ve and Gram -ve (just let SPSS know what 1 and 2 mean).

    For >3 eggs: Use an ANOVA (when parametric, assuming the above assumptions are met). Again, split file based on Gram +ve and Gram -ve. 

    Both of these techniques will allow you to compare the number of Gram +ve and Gram -ve bacteria in each of your eggs overall.

    Hope this helps!

  • Kenneth M Towe added an answer in Slope Stability:
    Relationship between calcium carbonate and Slope Stability?

    What is the effect of calcium carbonate in marl instability?In the other word, calcium carbonate increase slope stability  or decrease it?

  • Ji Ryong Cho added an answer in Calibre:
    How to estimate the contribution of the Flow Stability in the Measurement by Gravimetric Method?


    I am a Mechanical Engineer Student in Denmark, I am currently working in the final project in the design of continuous fluid flow generator (fluid:water).

    The working range it is wide from 1mL/hr to 6L/hr,the measurement process it is by a gravimetric method.

    This system it is intended to be used to calibrate the working standard reference of the hospital,this standard it used to calibrate infusions pump.  

    I would like to know if someone know how to demonstrate which it is the maximum allowable fluid flow fluctuation in order to do not affect or at least minimize the contribution of this fluctuation in the uncertainty.


    Javier I. Camacho

    Ji Ryong Cho · Inje University

    Dear Hernandez,

    Can you send me a sketch of your experimental setup for estimation of flow rate fluctuation?  

  • Terry Moore asked a question in Binomial Distribution:
    Earliest references to clusters of events having a negative binomial distribution

    It has been shown that a sum of independent observations from a logarithmic series distribution gives a negative binomial distribution when the number of terms in the sum has a Poisson distribution.

    I want the earliest reference to an equivalent way of looking at this, which I think is more intuitive (I assume I wasn't the first to think of it). Suppose that events involving k individuals have a Poisson distribution with rate proportional to p^k / k. If these events are independent then the total number of individuals involved has a negative binomial distribution.

  • Ma Rahman Bhuiyan asked a question in Dyes:
    How can we reduce the hydrolysis of reactive dye during dyeing with cellulosic fiber?

    During dyeing reactive dye react with water instead of cellulose which is known as hydrolysis. The hydrolysis of reactive dye in exhaust dyeing is about 20-40%.

  • In my msc culture in passage 1 I found a contamination that I don't know what it is. Would you help me identifying it, please?

    The black thing in picture.

    I change all of my materials and change my place but I see them after passage 1.they are float amd my cells are alive in that media.

    James Guest · University of Miami Miller School of Medicine

    Hi, my differential would be non-hyphated fungus, yeast, bacteria, mycoplasma and if the culture was primary just debris. In lieu of broth/agar cultures I would start with a gram stain.

  • Anna Bianchi-Smiraglia added an answer in DMSO:
    What must be the maximum final DMSO % in a cell culture plate (24 well plate) if I have to dissolve my compound in DMSO?


    Anna Bianchi-Smiraglia · Roswell Park Cancer Institute

    As a rule of thumb DMSO shouldn't be more than 0.5% in your cell culture. some cells can tolerate well up to 0.7-0.8% other are sensitive even at <0.5%. to rule out any effects of the DMSO in your system you may want to compare untreated cells and cells treated with various % of DMSO to find out what's the max they can tolerate for viability and any other parameter you're studying

  • Can bacillus subtilis be used as a probiotic after fulfilling all the criteria?

    I have a B subtilis isolated from fermented food showing characteristics of probiotic bacteria. Is there any concern regarding the use of bacillus as probiotics?

    Bipinraj Nirichan Kunchiraman · Bharati Vidyapeeth Deemed University

    Thank you very much Vittorio Capozzi for the information.

  • Why do particle suspensions exhibit shear thickening behaviour?

    Flow curves which I have obtained for 1% (w/v) suspensions of kaolinite clay, montmorillonite clay and silica microspheres all reveal shear thickening behaviour (an increase in viscosity) at higher shear rates. As I understand it, this is to be expected but I would like to know why it happens.

    Damian Kirchmajer · University of Newcastle

    Thanks Aroon, you're book was very helpful. There is a reference in particular from you're book that I would very much like to see but I can't seem to find it myself. It is reference number 141 from chapter 4 - 141. Govier, G.W. and Winning, M.D. (1948) AIChE Meeting, Montreal, Quebec. 

    Is there any chance you could forward me a copy if you have it?

  • How can we distinguish the normal fibroblast and senescent fibroblast in the culture?

    Can we distinguish the normal and senescent fibroblast in culture from their morphology? If during the prcess of trypsinisation if they are not getting trypsinised then can these fibroblast be said to be showing sign of senescence? 

    Goodwin G. Jinesh · University of Texas MD Anderson Cancer Center

    Compare panels A and B in the following link


  • Mohamed A. A. Mahdy added an answer in TUNEL:
    Why can't you use glycerol to seal DAB stained samples?

    as the title suggests, I want to know why glycerol can't be used on DAB stained slices. And there's something that's always been bugging me. I used a Roche TUNEL staining kit earlier and the manual specifically said that glycerol can used to seal the coverslips before looking at the results on a microscope, but the end product was stained by DAB. So was the manual wrong to say that, or is it just not something to be concerned about? I want to thank anybody who looks and answers this question beforehand, this is a great place to get answers.

    Mohamed A. A. Mahdy · Yamaguchi University

    We mount slides using Eukitt 

    You can check this chapter for your question


  • Mohd saleh Abbas added an answer in Demographics:
    What is the most efficient method to measure demographic factors as moderating variables?

    I am planning to investigate the relationship of core employees and organizational performance.

    My intention is to have the demographic factors as moderating variables and, if possible, to rank the importance of the demographic factors as moderating variables between core employees and organizational performance.

    Mohd saleh Abbas · UNISEL | Universiti Selangor

    Thank you Dr Peter Kellett. Will browse through the proposed website.

  • Aishah M Nasarruddin added an answer in HIV:
    Can anybody recommend a valid and reliable HIV risk behaviour assessment?

    To be used at 0, 3 and 6 monthly intervals.

    Aishah M Nasarruddin · University of Malaya

    That's really helpful Thanks! 

  • James F Peters added an answer in Acoustics:
    Can there be an effect of cavitation at an elevated pressure?
    Usually the effect of cavitation appears with a lowered pressure of liquid, for example, in water. However, this effect can be observed and at an elevated pressure. This effect was found by my research supervisor G. Askar'yan 50 years ago. I confirmed it experimentally. Without knowing this effect it is difficult to understand up to the end the cavitation phenomenon. These researches are published.
    James F Peters · University of Manitoba

    Dear Alexander,

    A lot depends on which edition of the Bible we consider in terms of page numbering. 

    For example, the 1611 King James Bible (KJB) had no page numbers.    To see how the pages in 1611 of folio edition of the KJB were labelled, see p. 54 in


    The first English folio edition of the Bible had 1464 pages, so the issue of the 666th page is not considered.