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  • Jack Silver added an answer in Toluene:
    What are the compatible solutes for HPLC c18 reversed phase columns other than toluene?

    What are the most common among them? Also what are their operation conditions?

    Jack Silver · Teledyne ISCO, Inc

    Ok- I understand now!

    Injecting toluene won't harm the column. It may harm your sample resolution.Toluene is a "strong" solvent for reverse phase, stronger than methanol. This means the sample could be carried, at least partially, through the column without interacting with the column surface. This reduces separation of your analyte from impurities. Depending on the amount of toluene, you may be able to get away with it though.

    See the link below, page 4, for an example of loading in a strong solvent. Although this is flash C18, it holds for HPLC as well.


  • Roy Youdale added an answer in Translation Studies:
    Can anyone provide some reliable online sources and document about translation quality assessment?

    I would like to write a literature review on this topic and I need more sources.

    Roy Youdale · University of Bristol


    In addition to Julianne House, you might like to look at this:

    "Towards a Dynamic Quality Evaluation Model for Translation" Sharon O‟Brien, Dublin City University, 2012. It's available as a  free pdf from here: http://www.jostrans.org/issue17/art_obrien.pdf

    All the best.

  • Can anyone help me in resolving the matrix to calculate the energy levels with Huckel methods ?

    Anyone can help to calculate with Huckel methods the matrix that gives the energies of the pro penal c=c-c=o

    Mohamed El Amine Benmalti · Université Abdelhamid Ibn Badis Mostaganem

    thanks,  your answers are quiet clear 

  • Is anybody working in CUDA language?
    CUDA C/ C++ for Windows 7 PC.
    Ahmed Hassan Yousef · Ain Shams University

    Yes, Any help??

  • Jack Silver added an answer in Toluene:
    Is anyone familiar with waters 501 HPLC solvent compatibility?

    I have an old "Waters 501 HPLC Pump" - I wanted to know what solvents this system is compatible with? I don't want to use it for LC, I want to use it as a pump for some organic chemistry flow reactions. Any ideas or a good website/reference?

    I assume it can be used for normal phase, so organic solvents should be ok, but I really wanted to know about toluene.


    Jack Silver · Teledyne ISCO, Inc

    Check that all fittings are tight. A loose fitting could cause air to be sucked into the system.

  • Raid Amin added an answer in Multicollinearity:
    How can I calculate VIF (Variance Inflation Factor) in Cox regression using R software?

    Hi, I am currently investigating the impact of D-dimer level on prognosis in patients with metastatic gastric cancer.

    Because the variable of interest was significantly associated with several covariates in Chi-square test, I think that the multicollinearity among these variables should be taken into consideration before Cox regression analysis.

    Is it possible to calculate VIF in Cox regression (R or SPSS software)?

    Raid Amin · University of West Florida

    Yes, only the predictor variables (x1-x5, above). 

  • Issue thawing embyronic stem cells?

    I am wondering if anyone has problems thawing embryonic or induced pluripotent stem cells.  In particular, I am finding that after two or three days post-thaw that the feeder layer becomes so dense that it chokes out the colonies that would have developed.  At the moment, I freeze down with feeders as these cell lines are not yet adapted to a feeder-free system.  If I get such high survival of feeders from my thawed vial, do I need to thaw on feeders?  Any advice?


  • Musa Peker added an answer in Self-Organizing Maps:
    How can I label the features in a U-matrix of self organising map?

    I am using kdd data set. And want to label all the features using a umatrix or is there any other option to do that.  Is there any function in matlab to do that?

    Musa Peker · Samandira Technical High School

    The following code can give ideas.


  • How can I compute connectivity numbers for skeletonization / thinning of 3D grayscale images?

    For binary (black/white) images, many thinning algorithms exist. However, few methods are available grayscale images, in 3D. I implemented the grayscale thinning algorithm for 2D[1], but now need to extend it to 3D. The key problem in this extension is to guarantee connectivity of the skeleton by computation of a connectivity number. Does anybody know an algorithm to compute a connectivity number for 3D grayscale image?

    [1] Kim et al., LNCS, 2006.

    Graham W Pulford · Thales Group

    Good question. I don't know the answer, but maybe it's related to clustering? You could  look at connectivity using a clustering measure in any dimensional space. I'm not sure how the grayscale affects things - but why not just bundle it into the clustering metric?

  • Noreen Gleeson added an answer in Gynecology:
    Is female sterilization using Pomeroy's Technique justified in all cases?

    As per rule/law, at least in India, we have to perform female sterilization with Pomeroys technique. But over the years, I came across several cases, where I feel this technique should not be used in some cases. For example
    Previous 3/4 cesarean section
    Previous rupture uterus and scar dehiscence this time
    Scar dehiscence without labour in previous one scar
    If we perform pomeroy's technque in these cases, there is a little chance of spontaneous recanalization, and surgical recanalization is never intended or advised in such cases.

    Noreen Gleeson · Trinity College Dublin

    Consider excising fallopian tubes or at least the fimbrial end to prevent serous cancers of ovary and peritoneum

  • Sherin Mohan added an answer in Cyber Security:
    Medical Device Manufactures VS Hospitals?

    From cyber security perspective; security experts should with whom for the safety of the medical devices? And why?

    Medical Device Manufactures



    Sherin Mohan · Bournemouth University

    I totally agreed to what you said above. however, Some studies recommends that hospitals should still hire security experts (within the hospital, not third party) just to deal with medical devices security. Do you think that is necessary if medical device manufactures work along with security experts?

  • Peter Li asked a question in Dendritic Cells:
    Can dendritic cells present multiple antigens in an inflammatory manner simultaneously?

    Say a DC becomes activated and presents some antigen - can it simultaneously present another antigen, whether foreign or self? If it can simultaneously present a self antigen, how does it prevent the body from forming an inflammatory reaction against the self antigen since it's an activated DC? 

  • David L Morgan added an answer in Grounded Theory:
    Can grounded theory techniques be used in research that does not intend to generate theory?

    There appears to a blurring of the lines regarding grounded theory as a methodology for analysing data and as a framework for generating theory. Can grounded theory be used as a research technique or methodology to analyse data only without generating theory?

    David L Morgan · Portland State University

    Charmaz, in Constructing GT, definitely argues that you need to be pursuing theory before you can call the method you use GT. Alternatively, if you are not generating theory, then one likely alternative is generate a Results section that is built around themes. In that, case Thematic Analysis is a very popular alternative for pursuing the same kind of essentially inductive analysis strategy (which also means that phenomenology is only one alternative to GT).

    Braun, V. & Clarke, V. 2006. Using thematic analysis in psychology. Qualitative Research in Psychology, 3, 77-101.

  • Tony Flowers added an answer in Visual Literacy:
    Does any one know of articles that discuss measuring visual literacy in visual narrative text?

    The majority of the articles that I am reader relate to test based on single images or photographs. The images selected don’t often contain any clear narrative structure. I am interest in visual literacy when applied to images read in sequence or as a part of a narrative structure. Not just as a supporting mechanism.

    As an illustrator, I am also interested in any research in this field conducted by other illustrators or image makers.

    Tony Flowers · University of Canberra

    Thank you Daniel, I will have a look. I unfortunately can't read Spanish, but I can find someone who can.

  • Good books on culture of tissues to recommend?

    I have to give a class to Master students on culture of tissues (not tissue culture know as culture of cell lines or isolated primary cells, but animal and plant tissues). I know only the basics and have experience only with culture of cells not whole tissues. Do you have a good book to recommend me that I could use to create my class? Thanks sincerely.

  • Nasser Belboukhari asked a question in Chirality:
    Is it possible to use three chiral columns in series for HPLC separation ?

    three column with diferent kind

  • Peter T Breuer added an answer in Bitcoin:
    How does BitCoin work?

    I'm afraid I haven't really been able to figure out the grand scheme of things, nor the technical detail, from the journalistic accounts I've read in the back pages of PC Weekly. All I can gather is that there is some sort of public visibility of transactions, and at the same time one can sneakily build up ones own "chain" (what is that?) of transactions and then usurp the public record with it if it gets big enough.

    Can anyone provide or point to an explanation of this alternative currency that says what precisely is public, what encryption mechanisms are used, if any, what is private, if anything, and so on? Enough detail that one could begin to think about the security or otherwise of what goes on, but enough abstraction that the overall picture is clear! What happens when A pays B an amount X?

    Peter T Breuer · Birmingham City University

    It doesn't matter what the times are estimated to be - and those estimates in stackexchange are  not justified as far as I can see - it's the principle that's the thing. There is no effective difference between running out at 2140 and not running out but expecting to take 100 years to find the next coin when that year comes round (and 200 years at year 2240, etc).

    And that's all quite irrelevant to the security, or otherwise.

    Come to that we already understand enough of how BitCoin works to know that they can simply say that bitcoins past year 2100 will use a new hash XYZ with a new mining requirement (starts with 49 repeated, for example), and everything is reset.

    Perhaps that's what "forking" the money supply will mean! Well, it's like Zimbabwe redenominating all its notes. All anyone has to do is declare their own currency and take bitcoins as input at a certain exchange rate, and go on from there.

  • Luis Fernando García added an answer in Statistics:
    Should I use the standard deviation or the standard error of the mean?
    Is the choice between these down to personal preference or is one favoured in the scientific field over another?
    Luis Fernando García · University of the Republic, Uruguay

    Sorry, just saw the discussion forum! What about the Confindence Intervals, is there any convention about when they should be used?

  • Kenneth M Towe added an answer in Climate Change:
    What is the climate change induced increase (per decade) in surface water temperatures and salinity in the worlds oceans and seas?

    Climate change induced an increase in the surface water temperatures and salinity in various oceans and seas in the world. I need the amounts of their increase per decade in past several years. Please attach the article as references with your valuable reply.

  • Lizzy Okoyeh asked a question in Oil:
    Can somebody suggest a laboratory where PAH and other parameters associated with crude oil impacted water and sediments can be analysed?

    The water quality assessment of  part of oil producing Niger Delta of Nigeria is in progress.What parameters in water and sediment samples are associated with oil exploitation.  

  • Brahmi Badr-Eddine Nabil asked a question in Wien2K:
    How to calculat the elastic proprities?

    I need to calculate the elastics properties by using  Wien2K codes

  • Is anyone using Methylene blue for SLNB in breast cancer patients?

    If yes, what percentage and quantity of the dye do you inject into the patient? Did you have high level of injection site skin necrosis and low identification rate as written in the literature?

    Mario Campli · Nuova Itor, Private Hospital, Rome, Italy

    Many years ago I used methylene blue in parathyroid identification 


    But technique was very different, I performed a preoperative systemic infusion (1 hour before surgery) of 500 cc of 5% glucose with methylene blue, 5 mg per kilogram of body weight. This resulted in the selective staining of the parathyroid glands

  • Any good source of banking sector-level data ?

    I identified IMF database and central banks reports. Do you know any free or payable data base with banking sector data for 1995-2013(4)?

  • Nigel Calder added an answer in Pedagogic Theory:
    What are the core features of mathematical reasoning among children aged 5-11years?

    What are the core features of mathematical reasoning among children aged 5-11 years old?

    Nigel Calder · The University of Waikato

    As well as the comment above, keys aspects of mathematical reasoning should include developing recognition and understandings of relationships and patterns, leading to generalisation. This might be enhanced by facilitating the posing of informal conjectures and prediction, and include creativity and logic. Mathematical knowledge and skills also need to be learnt simultaneously and co-relationally in different mathematical contexts e.g., in number, a focus on relationships could lead to enhanced number sense and understanding of place value.

  • Bernard Maroy added an answer in Depression:
    Why are antidepressants used for conditions other than depression?
    SSRIs are prescribed for conditions such as OCD, GAD, and even medical conditions like lower back pain? How do we explain the therapeutic use of antidepressants for diagnoses other than depression? How does the biochemical mechanism of SSRIs make them an effective treatment choice for other conditions?

    I am gastroenterologist-internist. Therefore, I have the advantage  to avoid blurring by current psychologic-psychiatric taboos.

    It's of paramount importance to criticize everything you have been taught.

    Open the eyes and you shall see!

    My method works since 35 y. on approximately 90% of my patients. This should interest every doctor concerned  by his patient's cure, even if it violates present taboos.

  • Are you familiar with research articles on whether using educational techonologies will enhance the learning expreience in medical field?

    Educational technologies including but not limited to the following:

    Using audience response system, distance learning- video conferencing & online learning etc. self learning modules using videos.

    Appreciate your time & help

    Silvia Schumacher · Barry University

    This article might be of interest to you.

    KEYNOTE LECTURE Preparing Healthcare Faculty for the Millennial Generation James B. McGee. University of Pittsburgh Pittsburg, Pennsylvania 15213 USA ...