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  • Kartinee Kassim added an answer in DPPH:
    Are there any researchers working on antioxidant activity?

    When I dissolve DPPH in acidified methanol(15% 1N HCl) it is showing yellow color. what might be the problem, is it acid or methanol or DPPH?

    Kartinee Kassim · Putra University, Malaysia

    I am agreeable with Dr. Jingbo Li, just dissolve DPPH in methanol. Do not use acidic condition. HCl is strong acid which can donate proton to DPPH radical and thus give yellow color. You may refer to my paper in Food Chemistry. Good luck

  • Does anyone have experience with extracting protein from RNALater stored tissues?

    Can anyone share their experiences with extracting protein (for IP/WB) with tissues stored in RNALater? On the product website, RNALater is supposed to preserve proteins as well as RNA.
    I ask this since we have noticed proteins stored in RNALater seem more degraded than other tissues that were snap-frozen liquid nitrogen and processed.

    The following image is from a stain-free gel on the Bio-Rad Chemidoc. We did this as we tried to understand why one student's blots (RNAlater hearts) were suboptimal compared to snap frozen ones.

    Boris Patrick Budiono · Griffith University

    Thank you very much for your well thought out answers..

    Mark: Yes, I went to that forum first and since it had limited information and was quite dated, I felt that this question warranted a refresh! Thanks for the lane width information, good thing to learn!

    Brian: It is great to hear that RNAlater should not compromise proteins in tissues for WB and to hear that your results have been sound. I am aware of the precautions to take in preparing an RNALater tissue sample for storage but will take better care in ensuring optimal volume of RNAlater and also to rinse it off prior to homogenising in RIPA (of which I did not do).

    Sidenote: I've noticed that there seems to be residual protein stuck on the top of my gel in the wells of muscle and pancreatic samples. The heart tissue was homogenised in a glass dounce while the rest was homogenised with LN2 with mortar and pestle. Speaking to a few colleagues isolating mitochondria for native gels, they noticed that suboptimal lysis of protein can show as "smeared" bands.

  • Suheir Nassar asked a question in QIAGEN:
    In DNA isolation from Stool using zirconia beads, would vortexing the samples be an alternative of using a bead beater?

    I am using the QIAGEN kit for  DNA isolation from stool for  bacteria detection. I am also using Zirconia beads for mechanical destruction of the bacterial cells as a step in DNA isolation. I don't have a bead beater , Omnilyser or similar instruments. Would vortexing the stool sample containing the beads be enough? if yes, then for how long do you suggest?

  • Abby Almarakshi added an answer in E-Learning:
    What are some of the challenges that can be encountered while applying ubiquitous e-learning to corporate training environments?

    I am looking for related literature that has done research about e-learning in corporate training? how they measure actual learning? What challenges they face when they design and deliver e-learning in corporate training program to improve job performance? If some of you could help, I really be appreciated your help. I couldn't find enough research that answers my inquiries? I am interested in e-learning in corporate training, what is their failure and succeed?

    Abby Almarakshi · Syracuse University

    Thanks Hector, I know kirkpatrick's four levels and Philips I'm gonna think about it. Meanwhile if you find journals or anyone can reach to help that would great. 

  • Len Bradshaw asked a question in Research Papers:
    Wanted Articles and Research Papers

    Wanted Articles and Research Papers for possible publication in the AMMJ - Asset Management and Maintenance Journal  www.theammj.com

    Topics Asset Management, Maintenance and Maintenance Management, Maintenance Engineering, Plant Engineering, Condition Monitoring, etc.

  • Raquel Galante added an answer in Surfactants:
    Can anyone assist with the investigation of lipophilic compounds release?

    Can someone explain to me how to measure the release of a lipophilic compound to gastric solution while this lipophilic drug can not be dissolved in aqueous? I used Surfactants and ethanol in release media, but did not observed any release.

    Raquel Galante · University of Lisbon

    It really depends on the nature of your compound, where and how It is releasing. But here are some ideas. I Hope it can be useful.

    -  Make sure that your compound is soluble in the release media first.
    -  Know the limits of solubility of your compound in the release media, and if necessary adapted your release assay protocol so that sink conditions are achieved at all times.
    -  If it is a bulk material (e.g. powders ) you can try decreasing particle size (turning it to nanocrystals). This technique usually helps to increase solubility/dissolution:
    “Development of nanocrystal formulation of meloxicam with improved dissolution and pharmacokinetic behaviors” http://www.sciencedirect.com/science/article/pii/S0378517314005882
     - Another way you can go is using nanocarriers:
    “Lipophilic drug loaded nanospheres prepared by nanoprecipitation: effect of formulation variables on size, drug recovery and release kinetics”
    “Nanostructured lipid carriers constituted from high-density lipoprotein components for delivery of a lipophilic cardiovascular drug”

  • Has anyone had trouble with permanent stains in magenta boxes after cleaning and autoclaving?

    I have had a persistent issue with a white stain being 'burnt' onto the magenta boxes I use for plant tissue culture after they are autoclaved. I have tried washing them and drying them by hand as opposed to using the lab dishwasher. I have drained the autoclave monthly. I have tried autoclaving boxes that were fresh from the factory and had never been used or washed in the lab. I have tried packaging the boxes so that they aren't just sealed with the lid but also placed in an autoclave safe package. I have allowed them to dry faster in the laminar flow hood as opposed to air drying on a bench. It does not seem to matter which method I use to clean and sterilize these boxes, about 25% of them end up with a caked on white residue that cannot be cleaned off. Has anyone has a similar issue when working with magenta boxes for plant tissue culture? I order my magenta vessels from sigma. I appreciate any suggestions.

    Patricia Rueda · Universidad Nacional Autónoma de México

    I have this problem only with the old boxes, maybe the problem is your water or abrasive things or soaps that you use for wash them

  • Can someone advise on choosing either inheritance or composition?
    Suppose you are working as a software developer in a company. You have been given a task to develop a software system design for some real world scenario. One of the basic activities of any software system design is to establish relationships between classes. Suppose at the stage of creating relationships for some classes, you have to choose either inheritance or composition as these are two fundamental ways to relate classes by achieving feature of code re-usability. Being a developer, for what reasons, would you prefer one technique to the other keeping in mind the reusability factor? Support your answer with solid reasons
    Giulio Zambon · University of Canberra

    Thanks Peter,

    I'll have to keep this issue in mind.

    Perhaps, anybody who notices such a question should point it out!

  • Paul Friesen added an answer in Language Teaching:
    How to test English speaking competence of primary students (11-12 years old)?

    Do you have any example test?

    How to evaluate the speaking competence of primary students?

    It would be very grateful if you can share me with some links or your own works.

    Thank you,


    Paul Friesen · Woosong University

    Competence is a big word. This concept needs to be defined before you start. Some can articulate their ideas well, others can speak in a conversation very well while not putting more complex ideas or changes in topics well. 

    As was suggested gve som starters and have students have a conversation. See if they can transition to topics, have extended sentences, and as quality questions. If they can paulthis without extra prompting then add the idea of grammar structure. 

  • What are the reasons of primer dimer formation in Real Time PCR?

    I am working on gene expression. In Real time PCR experiment, a primer dimer is observed.

    Kallidaikurichi V. Venkatachalam · Nova Southeastern University

    I endorse answers of subramaniam and Sabarish. Very good Response.

  • K. E. Basford asked a question in DAVID:
    I just accepted an author to a publication incorrectly. How do I change it?

    The co-author is David Edwards (University of Queensland), not David Edwards (from somewhere else).

    I can't remember the exact title of the paper.

  • Paul Friesen added an answer in Teaching:
    Does your position include teaching responsibilities and does your background include coursework in adult education teaching theories and methods?

    I am working on an audience analysis for a proposed workshop on using Angelo & Cross (1993) Classroom Assessment Techniques (CATs) in post-secondary education and training environments.  A response to the following prompts would be greatly appreciated:

    Does your position includes teaching responsibilities?

    Does your background include coursework in adult education teaching theory and methods?

    Does your institution promote or require the use of classroom assessment techniques (including online modes) as a research-based method for improving teaching and learning?  Do you think they should?

    Does your institution provide or offer any workshops or seminars for full and part-time (including adjunct) faculty on the use of classroom assessments techniques? Do you think they should?

    Would you be interested in attending (face-to-face, online or blended) a workshop or seminar on implementing practical, research-based, effective methods such as CATs to improve teaching and learning?

    Paul Friesen · Woosong University

    Does your position includes teaching responsibilities?

    Does your background include coursework in adult education teaching theory and methods?

    No, my background is in theology and Church Leadership. In a way yes for adults and children, but not in English. Over the past 15 yeas I have been involved with a wide variety of age groups, but not a lot on the theory. 

    Does your institution promote or require the use of classroom assessment techniques (including online modes) as a research-based method for improving teaching and learning? Do you think they should?

    This university does their own assessment of classroom techniques, but it is not related to this topic. 

    Does your institution provide or offer any workshops or seminars for full and part-time (including adjunct) faculty on the use of classroom assessments techniques? Do you think they should?  

    There are CPD presentations but most do not address this.

    Would you be interested in attending (face-to-face, online or blended) a workshop or seminar on implementing practical, research-based, effective methods such as CATs to improve teaching and learning?

    Yes I have an interest in this. 


  • David Hurem added an answer in Bromides:
    How to seperate Benzyl bromide from the reaction mixture.

    Benzyl bromide and the product formed are soluble in organic phase like ethyl acetate, the excess of benzyl bromide present in the product may lead to its deterioration. How to separate excess of benzyl bromide to get rid of this problem.

    David Hurem · Brock University

    Perhaps you could adsorb your product on an acidic or basic solid phase. Or you could extract benzyl bromide on C18-silica, leaving product in the eluent. Is crystallization an option? what mobile phase was used for the column? what is the order of elution?

  • Yuriy Kudriavtsev added an answer in Helium:
    What is the optimal value of the gas pressure in the mass-spectrometer?

    What, in your opinion, is the optimal value of the gas pressure in the mass spectrometric analyzer of helium leak detector in terms of increasing the sensitivity of measurements?

    1. The ion current increases at relatively high gas pressure in the analyzer chamber. The output signal and the sensitivity of the device rise in this case.
    2. On the other hand, the ion mean free path is reduced when the pressure increases. The probability of ions recombination grows.

    Can we analytically derive the optimal value of the gas pressure in the mass spectrometer in order to achieve high sensitivity?

    Yuriy Kudriavtsev · Center for Research and Advanced Studies of the National Polytechnic Institute

    "the optimal value of the gas pressure in the mass spectrometric analyzer of helium leak detector"

    If you say about vacuum, my answer is as high vacuum as possible. ANY residual gases give you a background.

  • Li Zongli added an answer in ANSYS:
    What is the best suitable element type for material non linearity problem for 3D geometry in ANSYS APDL?

    I am trying to carry out structural analysis on 3D geometry in ANSYS APDL 14.0 and the material properties for this analysis is of nonlinear type namely multinlinear elastic. I am unable to find the suitable element type for this analysis. Please guide me in this sense.

    Li Zongli · Northwest A & F University

    Above researcher have a good answers on this problem. In general, the more higher order element , the much accurancy for nonlinear materals.  

  • James Beveridge added an answer in Education:
    When and where should we use technology for education--in the classroom, outside the classroom, or both?

    I think most of us would agree that Technology Assisted Education (TAE), including both general technology and technology specifically for educational purposes, is of immense value for students of any age in any Learning Environment (LE).  However, the attached article points out some serious impediments to learning when allowing free and open access to laptops, tablets, and smart phones in the classroom.  Should these be "banned" from classrooms?  Should technology for education be focused primarily on outside class activities--homework, research, group activities, reading, testing, and the like? 

    James Beveridge · Valdosta State University

    When and where should we use technology for education--in the classroom, outside the classroom, or both?  Both!

    Should these be "banned" from classrooms? NO!  I believe that teachers/instructors/professors should have the academic freedom to choose the teaching tools and methods that they believe will best meet the needs of their students.

    Should technology for education be focused primarily on outside class activities--homework, research, group activities, reading, testing, and the like? No.  See my full answer above.

  • Tonya Ramey asked a question in Academic:
    Responses needed for academic science communication survey

    The goal of this study is to understand how academic scientists communicate with different target audiences, like resource managers, government scientists and the public. It focuses on the media the participant uses to get this information, and how often they use it, as well as what they do with this information.  The hope is to publish a paper that helps identify the best media to use for targeting these different groups

    Please participate in our 10-minute anonymous online survey.  We especially need respondents who are resource managers and other government scientists, as well as those working for NGOs--but all are welcome.  Thank you!


    (Please note the survey works better if taken on a computer compared to a smartphone, due to the survey site software.)

  • Is fiber optics sensors a promising tool for concrete structures monitoring ?
    This question is put just to launch a kind of opinion poll over scientist or engineers. In fact, even people who are non-specialists in the sensing systems or in SHM but who are likely to use monitoring outputs for their usual business (numerical simulations, structural analysis). My point of view is that this technique is promising with a high level potential of use but it needs more industrial experiences to be implemented as an industrial scale, such as "traditional" sensors.
    Leonid A. Skvortsov · Polyus Research & Development Institute

    Fiber optic sensors ( as part of the name optical fiber sensors ) is a fiber optic devices for the detection of certain quantities , usually heat or mechanical stress , but sometimes the same displacement , vibration , pressure, acceleration , rotation (measured by optical gyroscopes based on the Sagnac effect ) , and the concentration of chemical substances. The general principle of such devices is that the light from the laser (usually a single mode fiber laser ) or a superluminescent optical source is transmitted through the optical fiber, testing slight change its parameters in the fiber or in one or more Bragg gratings , and then reaches the detection circuit that evaluates these changes .
             In comparison with other types of sensors , fiber optic sensors have the following advantages :
    · They consist of an electrically nonconductive material (not require electrical cables ), which allows to use them , for example in the field of high voltage .
    · They can be safely used in an explosive atmosphere , because there is no risk of an electric spark , even in case of breakage.
    · They are not subject to electromagnetic interference (EMI), even nearby lightning and by themselves do not electrify other devices .
    · These materials can be chemically inert , that is non-polluting and non-corrosive .
    · They have a very wide range of operating temperatures (much higher than that of electronic devices ) .
    · They can multiplexing ; multiple sensors in a single fiber line can be integrated with one optical source.

  • Yuriy Kudriavtsev added an answer in RF Sputtering:
    Is anyone familiar with RF sputtering of ZrO2?

    I am trying to use RF sputtering to grow ZrO2 films on Silicon substrate. However, I found that the sputtering rate is extremely slow - on the order of about 0.1 nm per minute, which is unacceptable. Does anyone have any suggestions on how I could improve the sputtering rate? The conditions I am using now is as follows:

    Target: ZrO2 dielectric target, 3 inch diameter

    Gas: 20 sccm Ar, 3 sccm O2

    Pressure: 5 mTorr

    RF Power: 80 W

    Substrate temperature: 200 C.

    Substrate to target distance: 10 centimeters (can't change this much due to the design of the instrument)

    Thanks very much!

    Yuriy Kudriavtsev · Center for Research and Advanced Studies of the National Polytechnic Institute

    Low pressure plus low power.

  • Subhash C. Juneja added an answer in Leydig Cells:
    Can anyone tell me how long Leydig cells will be alive if I kept rat testis in -80 degrees freezer?

    I want to perform Leydig cell isolation from testis. How many months I can preserve rat testis for viable Leydig cells and what kind of media can be used for the preservation?

    Subhash C. Juneja · Toronto Western Hospital

    If you freeze the whole testis, I do not think any cell be alive. If you isolate the cells and use proper cryopreservation medium- like 10% DMSO with some serum and than freeze at -80 by using slow freezing (like 1C/min) Or using some freezer devices, your question can be valid. That is just my opinion. You may wait answer from other researchers.

  • Angela Cartland added an answer in Self Confidence:
    Is there difference or a relationship between self efficacy, self soothing and self confidence?

    Over the past year I have been noticing in clinic that people with chronic anxiety and depression, when asked to mentally simulate a situation in which they cope well with something, often tell themselves "It'll be ok" or "You'll be ok" but seldom "I'll be ok". I am currently designing a questionnaire to gather systematic data on this, with a hypothesis that there is an underlying prediction of "self coping" (different to self efficacy, self soothing and self confidence) which is inhibited or lacking in these conditions. I wonder, however, if I'm missing some other obvious connection and would value any thoughts or previous research on this.

    Angela Cartland · University of Canberra

    Have you looked at emotion regulation scales like the CERQ and the DERS?  Some of their sub-scales may be close to what you are looking for.  Same with the Affective Style Questionnaire.  Self-coping as a separate construct is a really interesting idea and I can see how it could be very valuable to measure in these populations.  Good luck!

  • Peter Benjamin added an answer in Fusion:
    Why doesn't d+d reaction give He4?
    We know following reactions:
    D+D = T + p
    D+D = He3 + n

    Why not: D+D=He4 + nothing?
    Peter Benjamin · Harvey Mudd College

    Ah, a new Pulsotron-3 design.  Very good.  And good luck.  I agree neutron generation is quite bad.  D+D is not going to provide long term feasibility, I believe. 

    Creating a preferential direction of neutron emission would allow easier collection of them.  Thus, to remove them from the chamber and neutralize them, like tokamaks are attempting.  Having a very narrow injection beam is my first thought.  Limiting degrees of freedom with polarizing magnetic fields might assist in that.  And encourage a higher fusion probability.  Creating a volume of space where the neutrons can be trapped and 'burned' up, would be an additional feature.  You mentioned that in a different question. 

    Doing all of the above would be a complex solution direction. 

    Does your design have ash collection/removal?

  • Yuriy Kudriavtsev added an answer in Devices:
    How is the work function of heavily doped poly-silicon carbide affected by temperature?

    doped poly-silicon carbide may be needed as gate contact for SiC devices.

    Yuriy Kudriavtsev · Center for Research and Advanced Studies of the National Polytechnic Institute

    This is subject of study, I think, especially for poly-C materials. For metals the dependence is linear:



    For semiconductor WF variation not so evident and depends on doping level.

    You may have alook: Semiconductor Surfaces and Interfaces by Winfried Mönch

    for details.

  • Oliver Olivarez asked a question in Mycobacteria:
    Is mycolic acid unique to mycobacteria?

    Are mycolic acid pathways found elsewhere besides Mycobacteria?

  • Is Knight shift affected by temperature?

    Knight shift is an NMR quantity that consist of two components, K =Kspin+Korb.
    What do these terms mean? Do they have temperature dependence? Can I observe both components of K at low temperatures?

  • Carolyn Hayle added an answer in Growth Economics:
    Does the investment climate determine the transformation of tourism growth into economic development?

    Tourism growth is the increase in the number of tourism product.

    Carolyn Hayle · The University of the West Indies at Mona

    Sure Jacob.  Let us talk.  Carolyn.hayle@uwimona.edu.jm.  Look forward to hearing from you. 

  • Shaima Mohammed Alghamdi asked a question in Designing:
    How to identify the upper, lower limits and the overlap values for a trapezoidal membership function ?

    If I am designing a fuzzy Logic system and one of the input variables is with two levels:

    Low:  having the range ( 0-2)

    High: having the range (3-5)

    If I am designing two membership functions to represent the two levels of the variable using a trapezoidal type, are the bellow values correct to form the trapezoidal:

    Low: [ 0 0 1 2 ]

    High: [ 1 3 5 5 ]

    If not, how can I consider the overlap area from the above mentioned ranges? 


  • Yarong Li added an answer in Ammonium Sulfate:
    Is there any way to detect ammonium sulfate (NH4)2SO4 concentration in a solution?

    It's required to detect the concentration of ammonium sulfate in a solution.

    Yarong Li · Office of Environment and Heritage

    Ammonium can be determined by FIA and sulfate can be measured by IC.

  • Kerrie Clover asked a question in Thermometers:
    Adaptions of the Distress Thermometer Problem List

    I am after articles describing any adaptations or validations of the Problem List that goes with the Distress Thermometer (in adult oncology patients).

    I am aware of Brennan et al in the UK and the NCCN alterations. I've had a reasonable search on Medline and of over 60 articles I've looked at no others appear to report changes to the Problem List, which seems improbable.

    Many thanks for any references suggested.

  • Kristin R. Carpenter added an answer in Welding:
    What is the effect of boron on weldability of S700MC?

    Hi everyone!

    I wonder about the effect of boron to submerged arc welding of S700MC steel grade.

    Why boron is not desired as an alloy element in S700MC ? 

    Thank you.

    Kristin R. Carpenter · BlueScope Steel, Port Kembla, Australia

    I agree with David. Small amounts of B are beneficial to hardenability, but the Boron needs to be 'protected' from forming precipitates as soluble B enhances hardenability. Too much soluble B can increase HAZ hardness, thus lowering toughness. Excessive B will precipitate, leading to brittleness.