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  • Na Le added an answer in Diffraction:
    Why do we have many small spots on electron diffraction pattern?

    Can anyone explain me why we have many smaller spot on the diffraction pattern despite the spots which are clearly visible. I attatched the images below.
    My suggestion is: the pattern recorded more than one crystalline, so the diffraction patterns of the two overlap.
    Can one make me clear about this.

    + 1 more attachment

    Na Le

    Thanks Janez Zavašnik  and Stefan Gajewski,

    Im now clear about the problem.  I have one more question. initially the crystal structure is diamond cubic Silicon (dc-Si), I took SADPs after the sample is damaged by laser. Then if the SADP have more than one crystals in focus.,how can I REFINE the dc-Si reflections. I mean how can I defined which spot belongs to dc-Si?
     2. And for twinning, any has some explanation how it is formed from diamond cubic structure by using laser?. I guess it because of the shear generted by laser shock wave, but Im not understand deeply it. 
    can anyone help me to explain it. thanks

  • Adam B Shapiro added an answer in Drugs:
    What could be the underlying reason behind antagonistic behaviour of certain herbals when taken along with chemotherapeutic synthetic drugs?

    Certain natural plant products show contraindications when taken along with an ongoing synthetic drug regime. What could be the most probable cause of such antagonistic behaviour shown by herbals?

    Adam B Shapiro

    Natural plant compounds are well-known to interact with drugs by affecting cytochrome P450 activity and multidrug transporters. A classic example is grapefruit juice.


  • Rizki Hanintyo added an answer in Water Sampling:
    Is it possible to measure reflectance of chlorophyll concentration on Ocean?

    dear all.

    i need to know, is it possible to measure reflectance of chlorophyll on ocean using spectrophotometer (using ASD Handheld spectrometer or JAZ Spectrometer)

    for example, 

    i will take some water sample on ocean and in the same time i will measure the reflectance pattern on the same site of water sample. is it possible to understand the reflectance pattern on different ocean chlorophyll concentration?

    thank you

    Rizki Hanintyo

    is there any reference how we can measure reflectance in the ocean? is it also same when we're measuring object reflectance in land?

  • Anberitha Matthews added an answer in Phagocytes:
    For how long do THP1 cells live/phagocyte after differentiation with PMA?

    After differentiation with PMA, for how long do THP1 cells live or can be considered active in RPMI media?

    Anberitha Matthews

    I have kept my THP1 cells for weeks after differentiating with PMA. I did a study that required the cells to incubate for 14 days. I had to change the culture medium about every three days but I added the same concentration of PMA that I used to differentiate the cells.  The only question that will remain is whether the gene expression will be the same after a prolonged incubation after differentiation.

    Generally speaking, always differentiate the cells fresh for each experiment to take out the probability of differentiation error.

  • Luis Pedro Miguel added an answer in Consumer Behavior:
    Is there work on PDO/PGI label consumer recognition in Europe and Portugal? Are there any studies on consumer awareness?

    My work is on PDO/PGI labels on meat fresh products in Portugal. Basically, I wan to to know if consumers recognize these labels when they see it and their idea about it. Is there any study on Portuguese market? 


    Luis Pedro Miguel

    Hi Rodoula, many thanks

  • Bo Xiong asked a question in Transformers:
    Can I amplify the bacmid DNA ?

    Hey guys, does anybody know if bacmid DNA can be transformed into DH10bac again to obtain more?



  • Anil kumar Mutyala added an answer in Polarity:
    Which one is polar? ethynyl-bridged bisphthalocyanine complex or ethynyl-phthalocyanine complex?
    Which one is polar? ethynyl-bridged bisphthalocyanine complex or ethynyl-phthalocyanine complex?​

    see the reference for more details   

    Which one is polar? ethynyl-bridged bisphthalocyanine complex or ethynyl-phthalocyanine complex?

    Anil kumar Mutyala

    Dear Alex,

    I agree with your comment.

  • Adam B Shapiro added an answer in Fluorescence:
    Is HS buffer compatible to use for absorbance read?

    HS buffer from life tech is used for fluorescence read on qubit 2.0 to quantify DNA. We are trying to have one buffer and take both absorbance and fluorescence from the same tube. Can we use HS buffer to absorbance reads?

    Adam B Shapiro

    As far as I can tell, the manufacturer does not state what is in the buffer. You can easily find out if the buffer is compatible with absorbance measurements by measuring its absorbance compared to water. As long as the buffer absorbance is low enough to avoid exceeding the dynamic range of the spectrophotometer, you can use it.

  • Edward Moh added an answer in His-Tag:
    How do I purify my protein?

    Hi guys, I tried using 30mM imidazole of binding buffer to perform affinity purification. After the purification, I found out that the band in red box(impurities) from eluent getting darker as compared to crude. The band in green box is the protein that I want.

    Anyone experience this before? Why is that protein bind to the resin? Is it because it contain his-tag as well? What is that actually? Any methods to remove it?

    P/s: my protein size is 113kDa and that impurities is between 35 to 25kDa. 


    Edward Moh

    Simplest way would be protein Id by mass spec. If you see the same peptides appearing, and some segments of the protein are missing in the smaller bands, then that is a clear sign that there is breakdown products. Alternatively, multiple bands appearing could also be from interacting partners of your protein. If you really want to get rid of it, perhaps purify your protein in denaturing conditions, or add in some detergents/salts to break the interaction. 

    Depending on your expression system, multiple bands might also be post translational modification, splice variants, or protease degradation. Can't say much since I don't know your protein.

  • Matthew Yu added an answer in War:
    Do you believe that Biological war is more dangerous than physical war with weapons?

    Biological war is basically microbe based war. Even your drinking water will be poison.

    Matthew Yu

    Biological war targets a whole population/ethnic group based on their genetic characteristics (may not be the only method, but a very destructive one), this would make it incredibly destructive than the traditional weapons. Yes, if there is a possibility that human beings can annihilate themselves, I guess they themselves would be the most probable perpetrators. 

  • Gerges Youssef asked a question in Replication:
    I have several readings for FEA results, I want to estimate which one is the most accurate one compared to experimental results. Can I use R2?

    The results are discrete values, where two parameters are varied for each reading (load and speed). Each reading is calculated only once (no replications).

    Please advise if I can use R2 as a measure for accuracy of results in comparison to the experimental results and advise how can I do calculations.

    Any suggestions for other measures/ parameters to determine accuracy?

    Best regards!

  • Mustofa Hilmi asked a question in eBook:
    Anyone have ebook"Chicken Nutrition: A Guide for Nutritionists and Poultry Professionals" ?

    anyone have ebook"Chicken Nutrition: A Guide for Nutritionists and Poultry Professionals"?

  • John Clarkson added an answer in UV-Visible Spectroscopy:
    Is there any possibility to calculate UV-Visible spectra of compound in different solvents?

    I installed GABEDIT and tried. i got  absorbance spectra of my compound. is there any possibility to find the absorbance in different solvents by using any software without using Gaussian. 

    John Clarkson

    GABEDITis appears to be only a visual interface for the likes of Gaussian, which indeed does contain solvent models for a lot of their structure / property determination methods.

    I guess you must have used a MO package attached to this to get your absorbance spectra? Which Molecular Orbital software package & method did you use?

    I'm not aware of other software, (free) that that can do solvent models for structure determinations & properties: This is advanced software.

    Why not try getting academic time on a computer that has Gaussian or similar, sayat  the national or State Supercomputer facility. Depending on the size of your molecule, you may need a lot of processing power, as the solvent structure determination & property methods can take much longer than the standard vacuum setting, at the same level of theory.

  • Srinivasan Ramani asked a question in Cellphones:
    What have we done to promote virtual cars as a sustainable form of transportation?

    Is it possible to reduce the private ownership of cars by promoting the use of virtual cars summoned by cellphone apps? What public policy recommendations have been made worldwide and what government incentives have been offered to achieve this?

    Background information: The use of computer apps to request taxi services has created a new industry, with companies like Uber and Ola growing at an impressive rates. However, Societies have not recognized that this new form of public services can contribute a lot to reduction of atmospheric pollution and traffic jams on the streets. It can also contribute to job creation. Visit

  • Lotfi Zeghadnia added an answer in Special Functions:
    How to compute Lambert Function (W)?

    Lambert function has been proposed by Jean-Henri Lambert, some times called Omegat function (W).

    the equation can be written as following:

     xexp(x) = z  this means that x= W0(z)

    So the question is , how can I compute W0?

    Lotfi Zeghadnia

    Dear Demetris Christopoulos:

    Thank you so much for your contribution.

  • Adam B Shapiro added an answer in Protein Aggregation:
    How to characterize protein aggregates by rayleigh scattering?

    How do we use use spectoflurometers to characterize protein aggregates through rayleigh scattering

    Adam B Shapiro

    I would discourage you from doing this. It will be very challenging to make any quantitative statements from the results because of the relative nature of fluorescence intensity measurements.

    Dynamic light scattering (DLS) or, better still, size exclusion chromatography coupled to multiangle laser light scattering (SEC-MALS), are better methods for characterizing protein aggregation.

  • Adham Sabri added an answer in RNA Extraction:
    Anyone familiar with RNA extraction from fish?

    hello i did extraction of RNA from fish using geneall kit and i used the TAE gel for rapid confirmation of RNA integrity.

    as I can see in the picture, i have the two bands of 26S and 18S but there is other bands in upper part.

    what is the possible cause of that? what is the nature of these bands?

    Adham Sabri

    Alisar Kiwan, normally we use homogenizer for homogenize the sample in our lab.thanks for your help

  • Oluwaseyi olubunmi Sodiya added an answer in Academic Writing:
    Does anyone have online academic writing exercises such as quizzes and the like?

    I need to provide some practice academic writing exercises for graduate students doing their final research papers. However, I thought I can save time by using what's available, so I am asking if you have such online resources that students can actually do online and receive automatic feedback (e.g., citing in APA, case study terms, etc.).

    Many thanks,


    Oluwaseyi olubunmi Sodiya

    Hi Debra , 

    Check the link here ,I guess its related to what you want . if you can't open the link, I have also attached the file doc for you . Wish you best of luck .


    + 1 more attachment

  • Adam B Shapiro added an answer in Biochemical Assays:
    Can anyone suggest biochemical assay for lipoxygenase from leaf samples?

    we tried to perform assay using linoleic acid as substrate (prepared freshly using tween-20, NaOH and water),but after adding substrate to the buffer (0.1M sodium phosphate buffer pH6.5) it turned turbid hence instrument could not get any readings

    is there a problem with buffer or substrate preparation?

    Adam B Shapiro

    The solubility of linoleic acid in water is pretty limited:

    In water, 1.59 mg/L at 25 deg C
    Mabrouk AF, Dugan LR Jr; J American Oil Chemists Society 38(1): 9-13 (1961)

    In phosphate buffer, the solubility is probably even lower because of the high ionic strength. Detergent should help, but the concentration of detergent may not have been high enough. The choice of detergent may also influence the solubility. I have used Triton X-100 successfully to make solutions of lipid-like compounds.

  • Jocelyn Amber Jones asked a question in Google Scholar:
    Are there any good sources for the extinction coefficient of streptavidin?

    I have been searching the links that google and google scholar provide, but the answers vary from 16,500 M-1 to 210,000 M-1.

  • Alexander T. Morchenko added an answer in Magnetostriction:
    Is there any instrument to measure magnetostriction curves of sintered ferrite samples?

    I am looking for Magnetostriction measurement of spinel and hexaferrite samples so any body suggest how to measure? which instrument can be use?. Our group is working on cobalt ferrite and strontium copper hexaferrites (M and Y type)

    R B Jotania 

    Alexander T. Morchenko

    Dear Rajshree,

    Here's another useful link for You: “The latest generation instrument is fully computer controlled and capable of displaying and measuring hysteresis (BH) loops, magnetoresistance (MR/GMR), and magnetostriction”

  • John Clarkson added an answer in Aptamers:
    Method for aptamer-gold conjugation

    What is more efficient method of conjugation of an aptamer to 40nm gold nanoparticles: using the thiolated aptamer or polyA one?

    Thank you.

    John Clarkson

    The thiolated aptamer should spontaneously attach to gold: you likely already know that!. Detailed methods....hmm: Examine the book below for more clues on gold antibody conjugates for useful info that you can borrow to design your own methods:

    "Lateral Flow Immunoassay", Wong & Tse, editors, Springer, 2009, ISBN 978-1-58829-908-6


  • Alastair Bain McDonald added an answer in Seabed:
    Can anyone comment on this map made by me presenting increased likelihood of methane in the southern Baltic?

    The map is  calculated on  the basis of  acoustic  observations of  the methane expulsions and  correlated type  of the  seabed - the  chart  of the  most probable  zones of  methane presence was calculated by me for  the  southern Baltic  Sea.  The methane  area is  well correlated with deeper stagnation areas.

    Alastair Bain McDonald

    I suggest you contact the Arctic Emergency Group http://ameg.me/

    or Prof Peter Wadhams of Cambridge University http://www.damtp.cam.ac.uk/user/pw11/

  • Hayk L. Khachatryan asked a question in Energy Materials:
    Does anyone know database where I may find tabled data of materials’ surface properties?

    I am looking for any data related to surface energy of materials. I need this for estimating hydrophobicity of thin films (e.g. SiNHx)

  • Michael J Jowers added an answer in Evolutionary Biology:
    How can I calculate qRST in SPAGEDI v1.5?

    Hi all,

    I am trying to use SPAGEDI v 1.5 to compare RST and FST statistics by pRst. However, the manual is not helpful on how I can compute these calculations. Would anyone know what steps to follow?

    Thanks and best regards

    Michael J. Jowers

    Michael J Jowers


    I am so sorry, I never got to thank you regarding my question on Spagedi!! I just realized! Many thanks and very much apperciated!

    Muchas gracias!


  • David A Johnson added an answer in Heteroptera:
    What are these bristles on the kudzu bug?

    Can anyone tell me what this pair of bristles found associated with every spiracle in the kudzu bug are? A pair is always found near the spiracle and the "crater" around the base of the bristle almost looks like another spiracle.

    David A Johnson

    Thanks so much for you answer and expertise.


  • Adam B Shapiro added an answer in Periplasm:
    Is it no expression or low expression ? If it is low expression how can I find that ?

    I trying to express mammalian membrane protein in ecoli system (with the optimized sequence) with the low copy number plasmid with the malE sequence (Periplasmic region expression).

    After expression(1mM IPTG) i am not able to see the any band at the desired place in the gel.

    What are all  the possible things for this no expression ??? or if there is any low expression how to find that ??????

    Adam B Shapiro

    If the protein is an enzyme, and it has an activity that is not found in the host E. coli, you can test for expression by assaying for activity of the enzyme.

  • Chloé Nobis added an answer in CD44:
    What are the optimal conditions for in vitro activation of CD4+ and CD8+ T cells using co-culture with allogenic bone marrow derived DCs?

    I try to activate the lymph node-derived CD4+ and CD8+ cells (separately) using allo-DC stimulation. I co-culture the DCs with T cells in 1:10 ratio in the presence of 100U/ml of IL2. But I don't see the increase in CD44+ or a significant reduction in CD62L markers. Is there some good protocol for allo-stimulation I can try? Any help is welcome as I'm quite new to the field.

    Chloé Nobis

    If you want to activate your T cells you need to activate and load your DCs with an antigen. In my experiment DCs activated with LPS is a negative control, that why you cannot see any proliferation or activation.

    I do not use any IL2 in this kind of system.

  • Hanan H. Abd-Elhafeez added an answer in ADD:
    Does anybody know how to calculate manually the scale bar in Carl Zeiss microscope ?

    I want to add scale bar to immunohistochemistry images. does anybody know how to calculate manually the scale bar. I used Carl Zeiss microscope for imaging the staining. I would appreciate if anybody know the easier way for calculation of scale bar. 


    Hanan H. Abd-Elhafeez

    Take image of ruler with different magnification of your microscope.
    then transfer measurement to equivalent from micron in each magnification.