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  • Mirza Arshad Ali Beg added an answer in Quinones:
    Does anyone have any ideas on quenching quinone-related reactions?

    Quinones are normally used to quench reactions.

    But I am working on reactions of quinone itself, and I would like to quench them. Do you have any suggestions on this? Just a situation in my case, the quinone compound is not stable under acidic conditions at low temperature (-20 oC).

    Mirza Arshad Ali Beg · Research & Development Consultants, Karachi, Pakistan

    Herewith are abstracts of a few papers that we published way back in 1969:

    Spectroscopic studies of organophosphorus compounds—III : The constitution of the phosphine-quinone adducts, M. Arshad A. Beg, & M.S. Siddiqui Tetrahedron

    Volume 22, Issue 7, 1966, Pages 2203–2211

    Pakistan J. Sci. Ind. Res., 12, 334-336 (1970) SPECTROSCOPIC STUDIES OF ORGANOPHOSPHORUS COMPOUNDS Part V.-Ultraviolet Spectra of Phosphine-j-Benzquinone Adducts M. ARSHAD A. BEG and M.S. SIDDIQUI P.C.S.I.H. Laboratories, Karachi 32 (Received February 17, 1969)

    The UV spectra of phosphine-p-benzoquinone adducts have been studied under acid and basic conditions. The position of the bands is susceptible to changes in pH. In the acid medium there is a decrease in intensity of the n+x transition, as in ionized carboxyls while in the basic medium, there is a red shift with an enhancement in intensity, which is characteristic of phenols. In the phosphonium dithioformates also similar variations are noted. These observations suggest that the betairie structure is favoured in the acid medium while the phosphinemethylene structure is dominant in the basic medium.

    Pakistan J. Sci. Ind. Res., 12, 337-338 (1970) THIOPHOSPHORYL ADDUCTS OF NITROGEN BASES M. ARSHAD A. BEG and M.S. SIDDIQUI P.C.S.I.R. Laboratories, Karachi 32 (Received March 10, 1969) Thiophosphoryl and phenylthiophosphoryl chloride have been shown to form adducts with ethylenediamine and dipyridyl in variable ratios. Similar adducts of pyridine could not be purified. The stoichiometry seems to depend on the number of chlorines attached to phosphorus. In the case of dipyridyl complexes, thiophosphoryl chloride forms the adducts in the ratio 2:5 while phenylthiophosphoryl chloride forms a 1 :I adduct. With ethylenediamine, on the other hand, the ratio with thiophosphoryl chloride is 4:15 and with phenylthiophosphoryl chloride it is 2:5 The adducts have been formulated as ionic substances.

    Pakisran J. Sci. Ind. Res., 12, 19-12 (1969) PHOSPHINE ADDUCTS OF POLYNITROARYLS M. ARSHAD A. BEG and M.S. SIDDIQUI P. C. S. I. R. Laboratories, Karachi 32 (Received July 9, 1968) Phosphines form addition compounds with polynitro aromatic compounds like picric acid, 1,3,5-trinitrobenzene and 2,4-dinitrophenol. Picrates of the alkyl phosphines are obtained in good yield from stoichiometric amounts of picric acid and phosphines, viz. trimethylphosphine, tributylphosphine, phenyldimethylphosphine, triphenylphosphine and tri-p-tolylphospine. The alkylphosphines react instantaneously at room temperature with the deposition of the intensely coloured compounds. Yellow solids which gradually transform into the deep coloured compounds are also obtained when the reaction is carried out at lower temperatures. With the arylphosphines an intermediate yellow solid is not obtained, the reaction is very slow and it is only on long refluxing that dark solid is obtained. Only the alkylphosphines react with the other nitroaryls. From the intensity of the colour and their reactions with acid and alkali the compounds are suggested to be zwitterionic in nature.

    There is also the Thesis on the subject on the HEC Website.

    You may suceed in partial quenching or selective quenching with alkyl - aryl substituted phosphines.

    Dr. Mirza Arshad Ali beg

    Former Director General PCSIR, Karachi

  • Weiwei Wu added an answer in Nanorods:
    I had some doubt regarding Dieletrophoresis method, can we use Ti/Al as an electrode for alignment of single nanorod on it?

    I had some doubt regarding Dieletrophoresis method, can we use Ti/Al as electrode for alignment of ZnO single nanorod on it.Please suggest some another material which can be used as electrode except than gold, which form's ohmic contact . Here we need this because we want to fabricate ohmic contact between this electrode and ZnO.

    Weiwei Wu · Technion - Israel Institute of Technology

    I use Ag before and get good ohmic contact. See the reference:"http://onlinelibrary.wiley.com/doi/10.1002/adfm.201101319/full"

  • Naveed Ahmad asked a question in Band Gap:
    How many ways to calculate the Band gap of a material by using UV spectroscopy data.?

    Please mention the way of calculation also, or provide the link of related article.

    Thank You.

  • Is energy minimization really needed for a typical MD simulation?

    Does energy minimization really needed for a typical MD simulation? I think the energy become minimum during for example NPT run. Am I ok?

    Sayyed Jalil Mahdizadeh · Ferdowsi University Of Mashhad

    Dear Vaibhav, thank you so much for your precious reply. I'll consider what you mentioned good.

  • Everett J Perkins added an answer in FDA:
    Could anybody help me with the guidelines or recommendations of FDA/EMA for the administration of ODT in bioequivalence & bioavailability studies?

    Could anybody help me with the guidances or recommendations of FDA/EMA for the administration of ODT in bioequivalence & bioavailability studies? Thanks in advance

    Everett J Perkins · Eli Lilly

    It should be covered under the immediate-release section of the FDA guidance: http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM389370.pdf

  • Is Chalmers' so-called "hard problem" in consciousness real?

    In his 2014 book "Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts" Stanislas Dehaene wrote "Chalmers, a philosopher of the University of Arizona, is famous for introducing a distinction between the easy and the hard problems. The easy problem of consciousness, he argues, consists in explaining the many functions of the brain: how do we recognize a face, a word, or a landscape? How do we extract information form the senses and use it to guide our behavior? How do we generate sentences to describe what we feel?

    “Although all these questions are associated with consciousness,” Chalmers argues, “they all concern the objective mechanisms of the cognitive system, and consequently, we have every reason to expect that continued work in cognitive psychology and neuroscience will answer them. By contrast the hard problem is the “question of how physical processes in the brain give rise to subjective experience … the way things feel for the subject. When we see for example, we experience visual sensations, such as that of vivid blue. Or think of the ineffable sound of a distant oboe, the agony of an intense pain, the sparkle of happiness or the meditative quality of a moment lost in thought … It is these phenomena that poses the real mystery of the mind”."

    Stanislas Dehaene's opinion is "that Chalmers swapped the labels: it is the “easy” problem that is hard, while the “hard” problem just seems hard because it engages ill-defined intuitions. Once our intuition is educated by cognitive neuroscience and computer simulations, Chalmers’ “hard problem” will evaporate".

    Personally, I agree with Stanislas Dehaene's opinion.

    Bernd Schmeikal · University of Vienna

    So you separate those layers, and how would you integrate them?

  • Jochen Wilhelm added an answer in ANOVA:
    How error is adjusted to avoid Type I Error in ANOVA?

    If ANOVA is applied in Static Group Comparison design, how error is adjusted to avoid Type One Error, in Bonferoni Post Hoc Test?

    Jochen Wilhelm · Justus-Liebig-Universität Gießen

    Bonferroni controls the family-wise error-rate, this is the expected rate of "at least one false rejection among a family of k tests".

    The probability of...

    ... a false rejection in a single test is alpha.
    ... not making a false rejection in a single test is 1-alpha.
    ... not making (even) a (single) false rejection in k (independent) tests is (1-alpha)^k.

    Thus, the probability of...

    ... making at least one false rejection in k tests is 1 - (1-alpha)^k.

    Bonferroni showed that 1 - (1-alpha*)^k < alpha when alpha* = alpha/k.


    Example for alpha = 0.05 and k = 12: alpha* = 0.05/12 = 0.00417

       1-(1-0.00417)^12 =0.0489

    so the expected family-wise error rate is close to the desired 0.05 if an individual null hypothesis from a family of 12 hypotheses is rejected only if p < 0.00417.

    Alternatively, instead of dividing the alpha by k and the comparing it to p, one can likewise multiply the p-value by k and compare it to alpha.

  • Are there recommendations that include choosing building materials that are more resistant by risk of flood events?

    Neighborhood patterns play an important role in alleviating flood risk. What is your opinion about that?

    Rolando Arturo Cubillos González · Catholic University of Colombia

    Dear Abdulatheem:

    Thank you for you answer. I take note for that and then I would like to discuss to you this topic.

    Best wishes,


  • Diana Luan added an answer in Sentiment Analysis:
    How can I research sentiment analysis on patients with shared texts?

    - which Data set is available that contains Patients profiles,disease features, medicine  and results , then the patient opinion  on medicine or on doctor 
    - What will be my contribution point if i applied sentiment analysis on this data set.

    Diana Luan · National Defense University

    I ran into this resource at the Robert Wood Johnson Foundation.  Take a look and see if this is a better answer to your question.


  • What is the minimum base-pairs required for DNA hybridization?

    I am doing a DNA hybridization test and wondering how many base pairs i need at least for the hybridization reaction to occur. Could you please share your expertise on this. Thank you very much ~

    Christian Q. Scheckhuber · Senckenberg Research Institute

    Yes, this is what I meant, H.H. Nguyen.

    Cheers, Christian

  • Thiago Wendt Viola added an answer in Acquisitions:
    Is it possible to carry out monochrome multiplex qPCR in an StepOne?

    I am trying to perform a monochrome multiplex qPCR for assessing telomere lenght based in Cawthon et al 2009. They used a master mix with Sybr green and telomere c/g and albumin as primers. The method relies in designing such primers that the products have different melting temp. The first signal acquisition detects the telomere product at early cycles and the second acquisition reads only the product of the albumin target,

    My question is: is it possible to carry out monochrome multiplex qPCR in an Applied StepOne?

    Thiago Wendt Viola · Pontifícia Universidade Católica do Rio Grande do Sul

    Cool! Thank you!

  • Antonio Curcio added an answer in Biomarkers:
    New explored biomarkers in cardiovascular medicine or cancer epidemiology

    Dear colleagues

    From your idea, what are new explored biomarkers for cardiovascular disease risk prediction? Which biomarkers are under research on the recent strong longitudinal studies in cardiology or cancer epidemiology field?

    Thank you very much

    Antonio Curcio · University Magna Græcia, Catanzaro, ITALY

    Hi Milad, in some circumstances you need to evaluate several new biomarkers and afterwards make your considerations based on those ones that are increased in the field you are investigating versus those that are reduced.

    You might find interesting the approach that we recently followed from genomics to proteomics at http://www.ncbi.nlm.nih.gov/pubmed/23276942

  • Can anyone provide some good examples of describing the Unit of Analysis in case studies?

    Identifying and describing the Unit of Analysis in case studies is a key requirement in such research, but what are good examples of such descriptions?

    Juan nicolas Montoya · National University of Colombia

    I recommend consulting Yin, although for many does not apply this type of estdudio, this author supports very well the advantages thereof. And while it does not define the conditions of a sample for analysis, I think you should at least contain the minimum elements that need to be evaluated in the study.

    Greetings to this beautiful land.

  • What are response surface methodology (RSM) with multi-responses?

    I usually see RSM-based papers with only one response. However, there are few reports on using RSM with multi-responses. I want to know if there are any difficulties or drawbacks relating to this procedure.

    Laxmana Naik · National Dairy Research Institute

    Hi Sara Asgari...

    Response Surface Methodology is ideally suited for  multi-parameters, and the  number of Responses may depends !

    I have tried  with 5 parameters for two responses (Antioxidant and Anti-Hypertensive activities)  in my research work, for optimization of Whey Protein Concentrate Hydrolysis. Initially I tried with One response and then in subsequently optimized for 2nd response from the first response data, as it was inter linked with first response. As In my case these two responses were linked with Molecular weight ( a specific peptides sequences), and both were interlinked. 

      If the Responses are independent then effect of each parameters will affect your result, and the interactive effect of each parameters (please see Table 4 of my publication) would again give different coefficient estimates, and at this stage it will become complicated, so when developing the regression equation (Y) of responses refining is needed.

    I have not given the clear answer, but hope it will give some insight and may help you a bit.

  • Vivek Anand added an answer in Nucleotides:
    Is there any function in R to convert nucleotide matrix to its frequency?




    Suppose if these are the nucleotides,

    The frequency matrix looks something like this,

    2 1 0 1

    0 1 1 1

    0 1 2 1

    1 0 0 0

    This is what I get from doing manually in R

    A <- c(2,1,0,1)

    C <- c(0,1,1,1)

    T <- c(0,1,2,1)

    G <- c(1,0,0,0)

    Any suggesion of functions in R?


    Vivek Anand · Rajiv Gandhi Centre for Biotechnology

    Thank you, Caner for the script.

  • Marzouk Lajili added an answer in Lignocellulosics:
    Does anyone know what the gases generated during the activation of lignocellulosic materials are?

    For environmental purposes, I would like to know which are the main gas compounds generated during the activation process of lignocellulosic materials in general, specially when you use Nitrogen as activating agent. 

    Marzouk Lajili · University of Monastir

    Hi cindy,

    Pyro-gasification can be realized using ligno-cellulosic materials in different atmospheres (first stape nitrogen N2 and then a mixture of steam and or CO2 in different molar compositions in order to converse the obtained char by pyrolysis). Obtained gaseous emissions are a mixture of volatiles CxHy (mainly methane) and the cyngas (CO+H2). The type of process concerning the heating rate (x°C/s) (fast, moderate or slow) is crucial for obtained comosition repartition between tar, char and gas.

  • Lalita Sharma asked a question in Methylation:
    Purification of Methylation product after methylation by M.sss1 transferase from NEB?

    I have methylated my DNA of interest  using M. Sss1 methyl transferase from NEB in 20 ul reaction set up as mentioned in their protocol.After this, I tried to purify that DNA by phenol extraction followed by ethanol precipitation. But I did not get any pellet of DNA after this. I started with 4 ug of DNA . What could be the reason? and secondly they have given the protocol for 500 ul reaction set up also and the purification step is mentioned in that protocol  only. so, does the small scale methylation (20ul) not require the purification step?  

    I am attaching the protocol here.


  • Ian Proffitt added an answer in Essential Oils:
    What are the alternate names for essential oils isolated from aromatic plants?

    Essential oils are also known as aromatic oils or fragrant oils or ethereal oils. What are the other names and in different languages? 

    IN UK English the older term is simply 'essences' or 'juices'. It was only in the late 19th century that the terminology became 'essential oils' .and juices came to mean something else. This older terminology persists in the Eastern US as well as in common, spoken English in more rural areas in England.

  • Respected friends and teachers please tell me which is the top journal of analytical chemistry ?

    please tell me which is the hot topic in analytical chemistry now , and what will be the hot topic in next 10- 15 years ?

    Hemn A. Qader · Hawler Medical University

    The hot topics at last 10 years ago, using of statistics in analytical chemistry especially chemometric techniques such as ANN, PLS, Design of Experiments, ....etc.

    Using of carbon nano tube techniques (CNT) for solid phase extraction

    Lab-on-Chip it is a techniques for miniaturizing of analytical instruments

  • How can I solve a non-linear Schroedinger equation (NLSE) to obtain the supercontinuum generation in PCF?

    I am trying to model a supercontinuum generation in photonic crystal fiber. In that case I need to solve NLSE to get supercontinuum generation. Can anyone suggest how would I do the same?

    Alan Robinson · 4D Optics

    G. P. Agrawal "Nonlinear Fiber Optics", 2nd editions, chapter 2, (1995) gives a useful overview of the nonlinear Schrodinger equation, and how it is solved.

    The split step Fourier method is commonly used to solve the NLSE.  The most appropriate form will depend on the power, dispersion and pulse width regime in which you are operating.  For short pulses (< 1 ps) you may need to include contributions due to Raman interactions and the frequency-dependence of the non-linear polarisation.  For very short pulses, a finite difference solution may be appropriate.

  • Where can I buy flat magnet wire?

    We need to wind a pair of anti-Helmholtz coils and we would like to use wire that has a rectangular cross section to maximize the filling ratio.

    Can anyone recommend a company that sells something usable (not to thick) and reasonably priced?

    Erkan Ilik · Eskisehir Osmangazi University


  • Andrew Herrmann added an answer in Feminism:
    If anyone has some good papers with the key words "Judith Butler, media and feminism"would you please share them with me?

    I need them for my Ph.D assignment.

    Andrew Herrmann · East Tennessee State University

    Though not addressing all of these keywords, I wrote this about CMC and gender a while ago. 

  • David L Hoffman added an answer in Mitochondria:
    I want to lyse mitochondria for measuring compex 1 activity.Is there any suitable protocol which can release the enzyme without damaging its activity?

    mitochondria lysis protocol

    David L Hoffman · Cayman Chemical Company

    If you've already isolated mitochondria from tissue/cells of choice a simple freeze thaw of the mito' will permeabilize the inner membrane so that excess NADH can cross.   You can measure the rotenone sensitive  oxidation of NADH at 340 nm in a spec or plate reader. Make sure you have an excess of  Q (Q2 C8081 from sigma) present, and inhibit Complex IV with an excess of KCN. Alternatively, you can run a high resolution clear native gel on samples where mito protein is lacking (link attached). It won't provide you with a linear rate, but rather an endpoint where higher activity results in a more robust band, as measured by densitometry. 

  • Balan Joseph added an answer in MATLAB:
    How to simulate a BELBiC controller in matlab for transformer protection?
    How to simulate BELBiC controller in matlab for transformer protection?
    Balan Joseph · Anna University of Technology, Coimbatore

    thank you sir 

  • How to develop a Linear Programming model for one crop?

    I want to develop a Linear Programming model for optimal resource allocation of one crop, for wheat. Is it possible to develop a LP model for one crop? If yes then please give me relevant literature or some useful links.

    Pradeep Dogra · Indian Institute of Soil and Water Conservation (Formerly Central Soil and Water Conservation Research and Training Institute)

    Given the constraints that you have against which you are optimizing an objective, which in your case is (maximum) total net returns (gross net profit), the different wheat varieties (say 4) cultivated under 2 different water availability conditions (rainfed and irrigated) can be taken to be distinct production activities (they will be 4 x 2 = 8). The LP objective function will be formulated with these 8 production activities and their coefficients will be the respective net return that can be generated per unit area. The land constraint can be separate for rainfed and irrigated, or can be one, depending upon ground situation. If irrigation water is limited (another constraint), then it can be one land constraint so as to allow utilization of maximum amount of available irrigation water (assuming that irrigated varieties have higher net profit than rainfed). Otherwise, there can be separate land constraints.

  • Anthony Castaldo added an answer in Matrix Theory:
    How do I calculate the maximum 'n*n' array size for a two-dimensional matrix multiplication program?

    I have a RAM capacity of 48GB. I wanted to run a matrix multiplication code which consists of five 2 dimensional arrays allocated dynamically with equal number of rows and columns. I wanted to know the maximum array size i can allocate? In other words what will be the values of rows and columns if my datatype is double?

    Anthony Castaldo · University of Texas at San Antonio

    An NxN matrix requires (sizeof(TYPE))*N*N) bytes.

    Five of them would require 5 times as much.

    Suppose your available memory is X bytes.

    The sizeof(double) is 8 bytes.

    So you are trying to solve for N in the equation:

    X = 5 * 8 * N*N ==> N = sqrt(X/(5*8)).

    Of course N must be an integer, and frequently your program will need to use some of the X bytes for program code, and most programs or linear algebra libraries need some workspace as well. So this equation will provide an upper limit on N.

    With 48GB of ram, X=48*(1024^3). By the formula above, N <= 35,895. More likely <= 35,000, to account for the overhead being used by the OS, stack, and rest of the program.

    How you search for a value that will work is up to you; I would try starting with N=35,000 and then reduce it by 1,000 at a time until you find a value that works.

    Typically, the memory allocation will fail (in C, malloc() returns a NULL pointer) so it is pretty quick to find both the last failure and first success. If you want, you can then do a binary search on that range to find the absolute maximum N your machine can support (and complete, because just allocating the arrays is not enough, if they take up TOO much room then later routines may try to allocate work space and fail, causing your full program to fail).

  • L. R. K. Perera added an answer in Slope Stability:
    What is the latest state of the art in weathering properties or indicators detection?

    Can you recommend a good paper that shows the sequence of events or related work done in rock weathering

    rock weathering, importance of rock weathering, effects on slope stability, indicators of weathering process, remote sensing, uav, lidar, field methods.

    L. R. K. Perera · University of Peradeniya

    Dear Atinuke,

    Go to the profile of Dr. Tilak Hewawasam at


    He makes use cosmogenic nuclides to determine rates of weathering.

    Best Wishes!


  • Zsofia Juhasz added an answer in Semigroup Theory:
    Does anyone know what the following type of languages are called (A language is a subset of the free monod A* over a finite alphabet A)?

    A language L over a finite alphabet A is any subset of A*, where A* is the free monoid generated by A. (A* can be identified by the set of all words over A, including the empty word.) Imre Simon defined piecewise testable languages using the congruence relation ~as follows. A language L  over a finite alphabet A is piecewise testable iff for any words v and w in A*, v ~m w implies that v is contained by L if and only if w is contained by L. (The definition of the congruence ~m I don't include here.)

    I am just wondering if anyone knows about whether there exists any terminology to describe those languages, which have a modified version of the above property. Namely, is there any name for those languages L over a finite alphabet A, which are such that for any words v and w in A*, if v ~m w and the first letters of v and w, respectively are identical then v is contained by L if and only if w is contained by L.

    Sorry if the definition looked like gobbledegook to you. :) I just took it from a paper as it was. However, your "decoding" is correct, too.

  • Luis Carlos Ramos added an answer in Plant Stress:
    What is the relationship between ABA and ethylene on osmotic plant stress?

    There are indications that ABA is a sign for stomatal  closure on osmotic stress. For ethylene, an antagonist of ABA action. So if we block ethylene action, we would eventually favor ABA action. That was not what I found by using an ethylene inhibitor (silver), looking by the plant response: they became more susceptible to the osmotic stress.

    Luis Carlos Ramos · Instituto Agronômico de Campinas

    Sasan, how would you measure stomatal aperture from over 60 seedlings every 2 hours for 48 hours, say? This is the time frame where my results happens... So, I rely on visual clues, that are highly evident.