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  • How do I synthesize positive charge metal nanoparticles using a green synthesis route?

    Is it possible to functionalize the metal nanoparticles through green routes in such a way that the surface charge will become positive?

    Shakti Ranjan Satapathy · KIIT University

    Sometime the charge of the reducing agent influence the charge of NPs especially in case of Green-synthesized metallic NPs. 

  • Maria Kolatsi-Joannou added an answer in Embryos:
    Can I store mouse embryos fixed with Den´s fixative (20%DMSO:80% methanol)?

    E8.5-9.5 mouse embryos 

    I want to do IHC in the whole embryo

    Maria Kolatsi-Joannou · University College London

    Hello Pachy, its best that you don't store the embryos in Dent's, just fix for 2hrs -overnight at room temperature depending on what you want to look for. Then transfer embryos to 100% methanol and store at -20 degrees for several weeks. I hope this helps.  Maria

  • Elena Yu. Ladilina added an answer in PDMS:
    What are the effects of UV on the PDMS backbone?

    Hey there folks, will try to be brief.

    I grow neurons on micro-fluidic devices made from PDMS, however due to experimental conditions, I can not use anti-biotics. In order to create a sterile environment, I have been using UV radiation. I have observed however, exposure for 50 minutes results in complete cell death, whilst 25 minutes of exposure results in neuron aggregation. 15/20 minutes seems to minimise this problem.

    I was wondering if there is a physical reason behind this observation, having already ruled out other possibilities (cell density, age of pups etc). I don't suppose free radicals, or silica layers are formed due to cross linking? Please share your thoughts, and thanks in advance.

    Elena Yu. Ladilina · Russian Academy of Sciences

    Use EtOH 1 minute, remove EtOH in vacuo,  and then fill up inert gas

  • Wa Go added an answer in Derivatization:
    Pre-column amino acid derivatization with OPA in HPLC. Quenching?


    Regarding the analysis of amino acids with HPLC the OPA reagent (ortho-Phthaldialdehyde) is suitable to make a pre-column derivatization of those in order to make them detectable with a fluorescence detector.

    In many papers it is written that acids (mostly acetic acid) is used to quench the reaction.

    1) Why is it necessary to quench the reaction?

    2) What happens mechanistically if acetic acid is added?

    Thanks in advance

    Wa Go · Leibniz Universität Hannover

    @Ravi Kant Upadhyay:

    You are describing the general procedure but your answer has nothing to do with my question.

    Further ideas concerning my question? Anyone?

  • Roland Schwald asked a question in Retail:
    What's the future for e-grocers or online grocery stores in your country?

    What's does the future hold for e-grocers  / online grocery stores  / Internet grocery retailing ?

  • Abrão Rapoport added an answer in CBCT:
    Is CBCT or CT more accurate for assessing the buccolingual dimension of ridge before implant replacement?

    as CT better resolution and accurate image of an object true scale 1:1 than CBCT.

    Abrão Rapoport · University of São Paulo

    I aggree partially  with Rubens:the choice depends on the professional skills and for each case

  • How do I determine and justify the sample size for a study involving couples?

    Is a couple considered 1 or 2 respondents?

    Timo Lorenz · Freie Universität Berlin

    Hello Aishah,

    die needed sample size depends on the tests you want to do and the effect you expect - N produces power - the lense to see your effect.
    There are some programs out there like G-Power to make statistical power analyses easy - have a look:


    I hope this is of some help.
    All the best

  • Guenter Grundmann added an answer in Tourism:
    Could you recommend papers or reports on mining tourism?

    I am looking for papers about mining sites converted into a tourist destination.

    Guenter Grundmann · Technische Universität München

    Dear Stefano,

    I have found another book in German: "Schau & Besucherbergwerke in Europa" ("Directory of visitors mines in Europe") by Heinz Walter Wild (1998), published by Bode Verlag, ISBN 3-925094-38-5 (see front cover of the book below).
    This is an excellent overview of the main visitors mines in Europe.

    Best regards,


  • Which topics in the field of mechanical engineering will be more on demand both in academic and industry in next five years?

    I am leading a research group including several graduate and undergraduate students in the field of multidisciplinary design optimization of mechanical structures and therefore always looking for new ideas and collaborations. Play always win-win game.

    Mostafa Ranjbar · Eastern Mediterranean University


  • Can Famacha chart be applied in Indian conditions?

    Anaemia Chart standardized by Faffa Malan be used as such in any country. If not then how can we go for standardizing a chart for our local use.

    Rajesh Katoch · SKUAST-Jammu

    It can be used, however CSWRI avikanagar has standardized card for indian conditions

  • Pavel Pazdera added an answer in Alumina:
    Can anyone provide me with papers about Heteropoly acids supported on Alumina?

    Any papers showing preparation, catalytic or photocatalytic activities of this catalyst would be appreciated.

    Pavel Pazdera · Masaryk University

    See +references herein:

    Polyoxometalates: Building Blocks for Functional

    Nanoscale Systems

    De-Liang Long, Ryo Tsunashima, and Leroy Cronin*

    Angew. Chem. Int. Ed. 2010, 49, 1736 – 1758

    DOI: 10.1002/anie.200902483

  • Detection of Genital Tuberculosis..PCR vs PAMP?


    I want to know the relation of Molecular PCR testing and Pathogen Associated Molecular Pattern detection by reproductive immunology for MTB detection in Genital Tuberculosis.

    There have been many conflicting view about the test. Recently I have noticed that PCR negative sample often is PAMP positive and clinicaly there is no MTB symtoms.

    Is this largely possible that due to tenhnical constraints a PCR negative sample my come PAMP positive without any cilinically relevant symtpoms...?

    Werner Solbach · Universität zu Lübeck

    If you suspect tuberculosis, you should aim to find the AFBs, either by microscohem, you py, culture or by PCR. If you don´t find them, you have either not got the right material or there is no tuberculosis. Fals positive PAMP tests to be expected.

  • Is there any role for hydrotubation following tubal reanastomosis and if so, when should it be done? What constituents are recommended to be used?
    During tubal reanastomosis one cannot achieve exact apposition between mucosal layers of both sides of fallopian tube. Methylene blue is introduced to assess the success of the tubal anastomosis. In case there is no spillage through the fimbrial end, does it always mean that the surgery has not been successful? Is there is any role for repeat surgery in the same sitting in such cases? Are guide wire/ probes encouraged during tubal recanalisation? What postoperative management can be carried out in order to retain tubal patency? Some surgeons advocate hydrotubation to increase the success of the surgery. I would like to see if there are references with regard to this or any other method that helps during and after such kind of surgery.
    Cristian Miranda · Hospital Clínico Universidad de Chile

    Today we do few tubal reanastomosis because our IVF Programm. But in those cases we use DR. Dubuisson JB "one stitch technique by laparoscopy" Hum Reprod. 1995 Aug;10(8):2044-6; without methilene blue test after surgery because high pressure into the tube with fine sutures is not good; without hydrotubations and if we need to look at an HSG three months after reanastomosis by laparoscopy

  • Can vaccines be targeted towards non-structural proteins and how effective it would be in comparison to structural proteins?

    whether structural proteins are good for vaccine development or non-structural proteins?

    Jarad Schiffer · Centers for Disease Control and Prevention

    Depends on what the vaccine is against.

    For viral vaccines, the target is typically a conserved surface protein, usually one required for binding to the target cell, as noted by Brian above.

    For bacteria, there are a wide variety of targets. Some vaccines can use anything on the cell surface (even some of the polysaccharide components of the cell wall) to trigger T-cell clearance of the bacteria and/or antibody-mediated serum bactericidal activity. Some bacteria secrete toxins (anthrax, tetanus, diphtheria, etc.), and the vaccine target is actually the toxin to generate neutralizing antibodies. Once the toxin is neutralized, these bacteria are easily cleared by the normal immune response. Some bacteria have specific virulence factors that must be targeted.

    The criteria isn't really that the target should be structural, but that it should be well conserved (to prevent escape mutations), it should be exposed to the immune system (so not something that remains internal to the virus or bacterium), and that the immune response to that target should effectively stop the infection. How that works varies depending on the organism you are targeting. The last one is what makes it so hard - antibodies to some targets don't do anything to stop the infection, and pathogens have evolved lots of ways to trick the immune system into attacking the wrong target.

  • Abbas Rahdar asked a question in Anisotropy:
    Why is The shape anisotropy called magnetic dipolar anisotropy?

    why is The shape anisotropy called magnetic dipolar anisotropy?

  • Tarun Kumar added an answer in Ubuntu Linux:
    I need a package to analyze behavior of code(time, power, space consumed) when we apply different optimizations on it. e.g: peephole optimization etc?

    I heard that Multicube Explorer can be used for this purpose. But I am unable to get it installed on my UBUNTU 14.xx machine.

    "collect2 ld returned 1 exit status" and a list of errors which says there is undefined referral to methods(which are in source code of Multicube). 

    1) Is there any other better option that Multicube Explorer

    2) If not, how this error can be removed?

    3) Is it possible that there can be issue with UBUNTU version (I am using 14.xx). Because documentation of Multicube, nowhere specifies any particular one.

    Tarun Kumar · Shiv Nadar University

    @Peter T Breuer: Thanks for replying. I have already searched on Google about error. This is the first thing that is expected from anyone getting any project error. I have already sent emails to related people. But couldn't get any solution.
    And my question here is to know whether there is any other option? Which don't need anything to be explained from package's documentation.
    Anyways, thanks for your answer and I really appreciate your work done.

  • Siji Narendran added an answer in Band Gap:
    How can the absorption coefficient be calculated using Tauc Plot?

    in calculation of Band Gap for semiconductors

    Siji Narendran · National Institute of Technology Calicut

    Dear Alexandre Henrique Pinto, please go through this..

    We have,

    Absorbance (abs) = log (I0/I)
    We can write I= I0e-αL
    So I0 /I = e+αL => αl=2.303 log (I0/I)
    => α = [2.303 log (I0/I)] / L
    Substituting abs for log (I0/I) => α = [2.303 (abs)]/ L
    L= path length, Io=> Input intensity, I=>Transmitted intensity.

    (answer is bit delayed.. just now only i noticed this question. this may be useful )

  • Samir Haddouchi added an answer in Microparticles:
    How can I determine the cumulative drug release from microparticles?


    I study on a drug delivery microparticle which contain antibiotic for joint infections. To determining the in-vitro release  profile, I suspended microparticles in PBS at 37C and at each time points I withdraw 0.5ml of PBS and replacing with 0.5ml of fresh PBS. Then I calculate the concentration of released drug with UV-Vis,  My question is how can I determine the cumulative drug release? Any help will be appreciated. Thank you.

    Samir Haddouchi · SPS Pharma Services

    In response to Claudio Nastruzzi: All the reasons you indicated are valid to not use UV. I just wanted to point out that very often, people think that HPLC is the only way to obtain precise and valid results...

    Cheers. Samir

  • Murat Sertkol added an answer in Monolayer:
    What is difference between monolayer and thin film?

    what is difference between monolayer and thin film?

    Murat Sertkol · Istanbul Technical University

    Langmuir is used for time that needed to cover one single monolayer of a surface under sticking conditions (assume sticking coefficient is 1.00) in UHV systems. 

  • Andrew Foy added an answer in CVA:
    What about acute MI with CVA at the same time?

    Today, I`ve seen a patient who has both MI and CVA at the same time! What are the possible pathophysiologic mechanisms?

    what will we investigate?

    Andrew Foy · Penn State Hershey Medical Center and Penn State College of Medicine

    On several occasions, I have seen this. In each case the patient had a large anterior STEMI that went undetected - either the patient was relatively asymptomatic and didn't seek medical attention or ignored the symptoms. The CVA occurred 2-5 days later and we speculated was caused by dislodgment of LV thrombus that formed after the MI and resulting apical akinesis. The troponin trend can be helpful to make this diagnosis. For example, if the troponin is already high and/or downtrending without significant upward slope then this is probably the case. 

  • Sherlito Sable asked a question in Secularism:
    Do you agree on what the author said that corporatism is a form of secular fundamentalism adopted in the global economy?

    corporatism as a form of secular fundamentalism in the global economy increasingly influenced and re-invented democracies to be more docile to the market forces.

  • Maintaining 'food security' of the world, is it possible to substantiate a significant amount of chemical fertilizers with organic inputs ?

    Organic farming definitely having some positive effect on food safety. But we can not ignore the aspect of food security in this context. So, maintaining food security  of the world is it possible to substantiate a significant amount of dreadful chemical fertilizers with organic inputs to combat environment pollution, maintain soil fertility status and provide relatively safe food to people? 

  • Maria Kozlova added an answer in Landsat:
    How can I get GVI values for Landsat 8 images?

    I study plant ecosystem dynamics using Landsat images in my work. One of the useful indices is GVI. I know it can be counted for Landsat 8 images but don't know how. Can anyone help me?

    Maria Kozlova · State Oceanographic Institute

    Thank you for your answers!

    It seems to me its time to go on with Grass 7.0. Grass 6.4 do not support  L8. Although I now count GVI values by handle entering of formula referred by Onur. Version 7.0 seemes to be much better of course.

  • Katia Ribeiro added an answer in Shimadzu:
    How to build the calibration curve for TOC SSM?

    I want to build the calibration curve for IC at Shimadzu TOC-L SSM using sodium carbonate (11.3 % of C) as a standard. Can you please advise me what amount should I take? Recently I tool 20, 40, 60 and 80 mg, but the device did not detect any peak.

    Thank you in advance!

    Katia Ribeiro · University of São Paulo

    You can use HNaCO3 for calibration for IC (14.28% C) as well. Important to remember that for TC the maximum limit is 30% C and 20% C for IC. In your case 80mg (Na2CO3) is equivalent to 9% C, an even lower value should be more detection. Be careful not to forget to inject into each sample the phosphoric acid (0.5ml). If the problem continues to call a technician, because should probably be Oxygen flow problem.

  • Can anyone give suggestions on how to obtain a calibration curve with correlation coefficient of 0.999?

    I have prepared calibration standards by diluting the zinc standard solution (procured from Merck) with deionized water to the desired concentrations. I am using volumetric flasks to prepare the calibration standards before transferring the solutions to the plastic centrifuge tubes. The plastic centrifuge tubes have been soaked in 1% nitric acid bath for more than a week and rinsed with deionized water before use. After three runs using the ICP-OES, I still cannot manage to obtain the correlation coefficient of 0.999. Thank you.

    Kathryn M. Conko · United States Geological Survey

    You need to have some acid in this solution, try 1% trace metal quality HNO3 at least.  Also, as mentioned before it is much better to make these up gravimetrically (record both the mass of the standard and dilution) and then calculate the exact concentration of your standard. For example you may think you are making a 1 mg/L with a pipette/volumetric but if you are very accurate you are really making 0.98 mg/L.  Another hint, on ICP-ES it's easy to use multiple wavelengths to compare- check another Zn line too.  Again, as mentioned, Zn is easily contaminated- keep your eye on this, but depending on the concentration ranges (would be helpful to know here) this may not be the first thing.  And last- does your ICP have dual plasma view?  are you using axial or radial view?  Zn is much better in the axial mode.

  • Does anyone know how I can fix this strange pattern of staining?

    I'm having this problem with some slides, where I'm not getting any uniform DAB staining in both true positive and false positive. It looks "wavy", and I'm not sure if this is happening because of the paraffin, concentration, etc.

    Does anyone recognize this problem and know how to fix it?


    P.S.: The antibody in the attached picture is ALK, the most problematic in the lab lately.

    Eduardo Rodrigo Fernandes Ribeiro · Federal University of Santa Catarina

    Apparently the problem was the distilled water. We have recently changed our water distiller, but I haven't thought about it until this week. So I brought water from another lab and it worked fine. I'm going to do some more tests just to be sure before changing the distiller again.

  • Armando Vieira added an answer in Machine Learning:
    Can Machine Learning Techniques Be Used To Predict Stock Prices?
    A large number of machine-learning models have been built to predict stock prices in literature. What are the main reasons why no one has achieved success so far?
    Armando Vieira · Closer

    They can as long as we are clever with filter of data and the methods. Deep Learning neural network approaches are particularly effective and long as we keep overfitting at bay.

  • Is anybody familiar with multi electrodes array and synaptic plasticity ?


    I'am using a planar multielectrode array system to record field potentials in acute hippocampal slices. In particular I am trying to study synaptic plasticity, but I encountered several problems.     

    After having setted my baseline (30-50% of max), I start a protocol, usally 1 train of HFS ( 100hz in 1 second, duration 200 micr-second). After I , unfortunately, find out that LTP goes in rundown. Very often. It is very disappointing.

    3 point more in the story:

    1) without induction protocol my baseline seems stable for about 2 h.

    2) I obtain some LTP with plateau or slow( acceptable) deacay. I mean, it seems that in some conditions ( but I don't konw why ) the induction protocol works.

    3) My conditions : about 30 °C; 3,5-4 mil/min ( but often a little bit less beacuse lower flows seem to prolong slices viability); titanium electrodes (64 channels, interdistance 200 micromt. , diameter 30 micromt.) with standard chamber ( electrodes are placed on the bottom of chamber and the slice is over them, submerged, so could be some problems of oxigenations) ; amplifier 1060 series. (Multy channel system ); I use a light mesh to hold the slices and my solution is the same that has  working for years for synaptic plasticity . 

    I hope that somebody could help me. In particular I refer to those people  used my planar MEA system.

    Thanks in advance

    Chang-Ning Liu · Pfizer Inc.

    We used MED64 system and MED-P210A MEA probes for LTP experiment. Other conditions:  31 °C, rat BW: 180-200g, [Ca]: 2 mM, [Mg]: 2mM. You may refer to the slice protocol at this link.

    Good luck!

  • Any recommendations for peptide desalting in mL range?

    I am searching for a good way to desalt peptides prior to mass spectrometry. Until now, I used zip tips for volumes smaller than 100 µL and that worked fine. However, now I am dealing with larger volumes (which is due to my specific protocol). I found several companies that sell C18 cartridges but honestly I am not sure how to use them (do I need special equipment?). Can anybody recommend something to me?

    Thanks a lot.

    Bernd Gesslbauer · Karl-Franzens-Universität Graz


    Cartridges work fine. You can use them like a syringe. You don`t need special equipment except a concentrator since you have also larger elution volumes.