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  • What is preparative chromatography? How it is done please explain step wise practically?

    The technique is needed for lutein extraction from marigold....which is my current research topic......

  • Dariush Azizi added an answer in Flotation:
    It is possible to use ultrasonic for separation of agglomerated particles which are treated by collector?

    In fact, I need to use agglomerated particles for flotation test. But, already collectors have been attached on the surface of particles. I don't if I use ultrasonic for separation of agglomerated particles, it may detach collector from their surface?  

    Dariush Azizi · Laval University

    Hi dear Mohsen,

    Thanks a lot, But using collector or agglomeration is out of matter for me. I already utilized collector in order to prepare particles for flotation, agglomeration occurs due to compacting of particle. I just have 5 g sample which has been compacted influencing previously done-preparation. My problem is to separate these agglomerated particles without detachment of collectors. I suppose ultrasonic may be effective, but I am concerned about its side-effect on the collector-particle attachment.       

  • Debi S. Saini added an answer in DAD:
    How to maintain or improve the teenagers’ relations with their fathers?

    Dear Professors/RG members/friends,

    In India most of the teen agers, when they join the colleges they stop talking to their fathers freely. They mostly approach the father through their mothers. This leads to the psychological depression of the fathers and since they don’t know how to correct this problem, behaves very strictly with their sons/daughters worsening the situation still more.
    Fathering a little son/daughter who wants nothing so much as to be "just like my dad" is much easier than fathering an adolescent son/daughter who wants to follow his/she own agenda and be his/her own man/woman.

    Dr. Shanmugasudnaram P

    Debi S. Saini · Management Development Institute Gurgaon

    I feel that especially in teens children go through a lot of physical and psychological changes. They need to be understood carefully.  There is a need to communicate with them regularly. Often, they do not like to do that with parents, as they have new fascinations which they like to explore. Interestingly, as they grow up, they become much more understanding and affectionate. 

  • Nadia A. Salman added an answer in Virus:
    What is the best PCR kits for HPV detection?

    I would like to detect human papiloma virus (all types) using PCR. I would like to know if there is anyone who has experience and knows what is the best method for detection of hpv in blood. 

    Nadia A. Salman · Kingston University London

    Dear Davod & Mona,

    You can detect HPV DNA in blood samples as the HPV DNA have been already detected in peripheral blood samples by others. Please take a look at the attached articles !

    Do the DNA extraction first and then the PCR.


  • Surendra Nath added an answer in Floriculture:
    What is the fullform of YCD-1 in Gerbera (Floriculture)?

    Dear All,
        Myself Dr. Kiran Ranadive, Asst Prof of Botany in Waghire College Saswad. I am teaching FYBSC Paper II , in which Floriculture is one of the topic. Today i have taught the Gerbera cultivation, there are so many varieties of the same but i have't got any clue that why the variety YCD -1 , 2. What is the fullform of YCD?
         If anybody could send me the answer then it will be very much informative to my students during learning the same. If anybody could send me the floricultural PPTs then it will be great help for my student to start business in floriculture.
         I hope that you will send me the same at your earliest.Eagerly waiting for early reply.
    Thanking you

    yours sincerely

    Dr. Kiran Ramchandra Ranadive

    Surendra Nath · Tamil Nadu Agricultural University

    yes it is for Yercaud,,,a hill station in Salem, TN.....Horticultural Research station, Yercaud (YCD) developed the variety for Gerbera....

  • Abdul Hameed added an answer in Seeds:
    How much seeds sample is it required to measure the MDA content in the seeds?

    Does anyone know how much seeds sample is it required to measure the MDA content in the seeds?
    Thank you!

    Abdul Hameed · University of Karachi

    I use 0.5g seeds for this purpose

  • Surendra Nath added an answer in Chrysanthemum:
    Does anyone have an idea on double haploid production in Marigold/Chrysanthemum?

    I want to develop DH in Marigold through another culture. Can anybody suggest the protocols available on Genotype selection, Media composition, Hormonal concentrations, stage of flower bud development, pre-treatment etc.

    Surendra Nath · Tamil Nadu Agricultural University

    A lot of such work is available in china......but most of them being published in chinese....i have come accross from some of the abstracts......

  • Lena Vider added an answer in SDS-PAGE:
    Does anyone know why streaky bands appear on SDS-PAGE for Western Blot?

    I am doing western blot with brain protein samples. I loaded replicates of 5 samples in 4-12% Bis Tris gel and cut it in half.

    I found that sample 2 and 3 are streaky at replicate #1, but sample 2 was still streaky but sample 3 was not streaky anymore in replicate #2.

    I loaded them all at the same time with the same pipette. While gel was running, all the other samples were migrating with flat line shape but the streaky samples were migrating with thin triangle shape, so that we already knew those samples will be streaky like something is pulling them down the gel.  

    Does anyone know what could cause streaky bands on SDS-PAGE?

    Lena Vider · Griffith University

    Hi Ky Lee,

    I would re-spin samples. Most probably there are some impurities in the sample as suggested by Christian.



  • Nayem Zobayer asked a question in Protein Sequencing:
    Protein sequence of Minnelide or Triptolide?

    I have searched in ExPASy about the sequence of  Minnelide or Triptolide. Can any one suggest where I can find the protein sequence of those two. And please let me know, if genome sequence of Tripterygium wilfordii is available.



  • How to identify 'parasitism' in practice?

    The definition of parasitism implies that some living beings named 'parasites' take energy for individual survival at costs of living beings named 'hosts'.

    Terminology 'host' might give the impression to 'non-specialists', like tourists, that parasites are always mentally invited to take energy. In addition, humans often give 'energy' (e.g. blood) without knowing the true identity of receivers, thus without having access to perceived costs or benefits involved.

    How to make practically a distinction between 'taking', 'giving' and 'sharing' in Parasitology or Sociology when mental states of actors are ignored?

    Marcel M. Lambrechts · Centre d'Ecologie Fonctionnelle et Evolutive, Montpellier, France

    Should by definition parasites always be physically attached to hosts, or not? Based on the examples provided, the key is apparently draining energy from others in an unbalanced way, what then what about the definition of predation versus the definition of parasitism versus the definition of exploitation versus the definition of .....?

  • Surendra Nath asked a question in Lutein:
    I m doing my research on lutein marigold extraction and further its encapsulation. can any body help me in techniques of extracn esp soxhlet?

    I have many articles regarding different methods especially,,soxhlet, enzymatic extraction, methanol based extraction...but I cant get a practical point of doing it.....especially after extraction I have to find the concentration of lutein obtained.....paper and HPLC will be used. But for higher quantity,,,paper or TLC will be used......please help me in understanding the practicallty of the work......urgent

  • How do you currently manage asymptomatic thoracic aortic free floating thrombus lesions? TEVAR, open surgery or anticoagulation?

    There is very few data on how to manage these lesions, but the thromboembolic potential seems to be high, namely visceral and renal artery ischemia. Do you think we should preemptive treat these patients?

    Paulo Eduardo Ocke Reis · Universidade Federal Fluminense

    Dear Hugo Rodrigues,

    That`s a very good question!

    I agree with Julian Strobel 100%.

    First of all good surveillance and therapeutic anticoagulation if such thrombi need to be treated.

  • Recently, I have isolated a novel compound with slight impurity. Shall I purify it or proceed to NMR to disclose its structure prior to purification?

    I have isolated a novel compound from fraction library and there is a slight impurity which is detected using LC/MS analysis, where a small ion peak is detected besides the molecular ion peak. Thus, I am hoping to get some opinion from RG members for whether purification work should be done now or shall I proceed to NMR analysis for structural disclosure before any further purification? As such minor impurity in the main compound might not have a significant effect on NMR spectra measurement. FYI, the amount of the compound I obtained is less than 2 mg.

    I would greatly appreciate for any advice, suggestions or comments. Thanks in advance. 

    M. Ángeles Ramírez-Cisneros · Universidad Autónoma del Estado de Morelos

    I agree with idea of obtain 1H-NMR spectra and proceed to purify, but, I run also 13C-NMR; although do you have already  any NMR spectroscopy? because you affirm to had obtained a novel compound...

  • Manuel Sanguinetti added an answer in Plasmids:
    Dear sir I want to amplify a cDNA using pfu polymerase. pfu amplifies the target cDNA but it doesnot amplifies the positive control plasmid DNA ?

    I am using Fermentas pfu polymerase. it is provided with single buffer vial which has MgSo4 also.

    Manuel Sanguinetti · University of the Republic, Uruguay

    What is the amount of plasmid you are using for your PCR reaction? Maybe the difference is the amount of target DNA you are using. Remember that when using plasmid you should use a low amount of it (10 ng tops)

  • What is the reason of spikes in the radiation pulses in Free electron laser ?

    I know, use of  non-uniform current and the  slippage effects are the reasons of spikes in the radiation pulses in Free electron laser.

    Now, I am looking for other reasons.


  • Lena Vider added an answer in Mycoplasma:
    Mycoplasma in lentiviral packaging cell line?

    our packaging cell line was infected with mycoplasma, and virus-containing media also contains mycoplasma. It is recommended to discard it, but is there any other way?
    we ve thought to centrifuge media and to remove supernatant, and to add mq-water to lyse mycoplasma. They should "explode", but after that how to check mycoplasma by pcr if dna will remain there?

    Lena Vider · Griffith University

    Hi Daniel,

    If you can not replace virus producer cell line, you may try to treat cells with Plasmocin or Plasmocure (Invivogen).

    Invivogen have pretty good kit to test mycoplasma contamination as well.

    Good luck!


  • MouLeong Tan added an answer in ArcSWAT:
    Error while delineating watershed in SWAT?

    I am getting an error: "no features found. possibly an empty feature class." while delineating watershed in SWAT from DEM. I am using ARCGIS 10.1 and ARCSWAT version 2012 .

    sometimes the error occur as :

    " the watershed with grid code does not have an outlet within it . This is  likely because the outlet falls on a edge of the watershed boundary."  for the same process...

    MouLeong Tan · Universiti Teknologi Malaysia

    I think you can check your DEM data or try different DEM products.. All the best..

  • Alvin Vista added an answer in Survey Analysis:
    Is it correct to map the "means" into "equal intervals" to facilitate the interpretation of the survey results?

    I saw some researchers who used this formula: (n-1) / n, where n is the maximum number in the used scale. For example in five-point Likert scale, n is equal 5. So, the interval size can be calculated as 0.80. I just need a confirmation or precise evidence 

    Alvin Vista · University of Melbourne

    I think it might be better to convert a set of Likert-type questions into a (larger) set of dichotomous questions that are forced-choice types -- then the item/question set can be properly quantified by scaling them via IRT or other scaling methods.

  • Majid Saeedi asked a question in Switches:
    Bypass disconnect switch (by-pass) is? What is the purpose?

    Bypass disconnect switch (by-pass) is? What is the purpose?

  • Arunas Ramanavicius added an answer in Thin Films:
    Regarding nanocrystalline diamond vs diamond-like carbon, can someone help me about their deposition and properties?
    To my knowledge, both materials can be deposited by plasma assisted CVD from generally the same precursors. Only the deposition conditions (like the way of plasma excitation and frequency and gas composition) differ. Are these completely different materials or can they be substituted? How about conductivity/doping? Can anyone direct me to valuable reading about the topic?
    Arunas Ramanavicius · Vilnius University

    Hi (sveikas!) Dariau, Some related publications are attached, If YOU need some more INFO or some nanodiamonds contact me directly. Sincerely, (Iki!) Arunas

  • How do you predict drug-drug interactions?

    Is there a computer program for predicting drug-drug interactions? Who can supply this?

    Ahmed Farghali · Qatar University

    Simply to predict DDI without checking any databases:

    1- some are CYP-450 liver enzyme inducer which will decrease the effect of other drugs so the dose may need to be increased.

    2- on the other hand , some are liver enzyme inhibitors which will increase the blood conc. and or risk of toxicity so requiring dose adjustment or discontinuation .

    3- some drugs like PPI and H2-receptor blocker decrease the gastric acidity so decrease absorption of other drugs.

    I am sorry I didn't see the full question , I saw only 1st part of DDI but if you need computer program there are many available for example : we  use in our hospital Hamad General Hospital : lexi-comp & micromedix .

  • In your country what energy source (residential use) is most used:NG or electric energy?Gas network has 100%coverage? What factors determine this?

    In São Paulo, the most important city in Brazil, there is a difference of nearly 100 years between the expansion of the electricity network and natural gas (NG) distribution pipelines.

    The gas only gained momentum since 2000, while the electricity followed the development of neighborhoods.

    The use of electricity Is still the predominant, based on the following factors:
    -The energy matrix based on the use of hydropower and on the electricity that they generated;
    -Electric energy tariff is still lower than gas;
    - Many houses and buildings have no facilities adapted to use gas.

    There are reports / papers on this subject?

    Thank you for helping!

    Vanessa Meloni Massara · University of São Paulo

    Dear Dr. Roland,

    In general terms in Romania, is similar to the Brazilian situation.

    Thank you for your attention. Your response will be very useful.
    Best Regards,

  • Alvin Vista added an answer in Multiple Regression:
    Has anyone used a Venn diagram to illustrate shared amount of variability in DV among multiple IVs?

    I have seven IVs that can predict a DV. All IVs are correlated (no multicollinearity issues). I find R2 and Cohen f2 values difficult to interpret because each IV shares some similar and different variances accounted for in the DV.

    Has anyone had experiences in creating a Venn diagram to illustrate the shared amount of variability in multiple regression context that can direct me to existing resources or know a software that can generate the diagram?

    With thanks, Joe

    Alvin Vista · University of Melbourne

    yes, I use Venn diagrams to explain the concept of variance explained.

    they are also useful in explaining the concept of partial correlations.

  • Mir Faeq Ali Quadri added an answer in Obesity:
    What is your opinion on relation between obesity and caries?

    Apart from having common risk factor 

    Mir Faeq Ali Quadri · Jazan University

    Dear Dr. Vaccaro and Dr. Venkata,

    Found some articles during my lit search 

  • Ioannis Delimaris added an answer in Saliva:
    What is the best method to determine total antioxidant status/capacity in whole human saliva?

    Human saliva can be collected noninvasivelly and includes numerous molecules that could have a role as potential biomarkers for research studies. In your opinion what is the best method to determine total antioxidant status/capacity in whole human saliva? Has anyone tried a (suitable for saliva) assay kit ?

    Ioannis Delimaris · Harokopion University of Athens

    Thank you for the references.

  • Igor L Shabalin asked a question in Diffusion:
    How do we need to modify the Darcy's law equation for gases in nanoporous media (Knudsen diffusion) in the case of gaseous counter diffusion?

    In particular, for nanoporous media with parameters variable in time, temperature and pressure (for details, please, see my publications on ridge-effect phenomenon).

  • Is there any standarised nomenclature for molecular vibrations?

    I've seen several publications and in many publications the abbreviations for the molecular vibration modes using greek letters don't match with others even if they refer to the same. The only exception seems to be the use of nu for stretching (both sym and asym). I've seen using delta with different subindexes for all deformation modes but in other they use gammaw for wagging mode for example.
    So, I was wondering if anybody know if there is any standarised or regulated nomenclature on this (IUPAC?) or if it just depends on the author.
    Thank you.

    Vito Librando · University of Catania

    There is not a IUPAC standard nomenclature  for molecular vibrations  but there are several books that can help to interpretate IR and Raman spectra: if you need I can suggest someone.

  • Rodney J. Ouellette added an answer in Ion Torrent:
    Is anyone using the Ion Torrent sequencing platform for clinical diagnosis outside of a research protocol?

    We have recently begun using the technology in the clinical setting and I would like to know if any issues relating to mutation calling have been encountered by others in this context.

    Rodney J. Ouellette · Atlantic Cancer Research Institute

    Thank you Nandagopal. We feel that the calling has improved greatly with enhancement to the system software.  Also more coverage improves read accuracy.