Q&A

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  • Piyush Srivastava added an answer in Yeasts:
    Is there any other way to induce the GAL1 promoter in yeast PJ69-4A without using raffinose?

    I actually inserted my target DNA in pYES2/NT B vector and transformed in yeast PJ69-4A, and want to express my target protein in yeast PJ69-4A. 

    I still haven't received a satisfactory result.

    Piyush Srivastava · Central Drug Research Institute

    Curt ! can u suggest, which yeast strain we can use?

  • How to calculate sample size for survery research?

    what is the simplest formula for calculating the sample size in survey research?

    Professor Muayyad Ahmad · University of Jordan

    Thank you Dr. Arup Barman

  • M Raza Ali added an answer in Tracking:
    Long-term tracking, the best algorithm from your point of view?

    From your experience, which is the best long-term tracking algorithm ?

    M Raza Ali · The University of Manchester

    What kind application are you working on? We have used Bayesian tracking for multiple users (gesture recognition); with tracking session varying from 2 to 7 minutes.

  • Alexander S. Solntsev added an answer in Photonics:
    In which sequence one should start the research in the field of nano photonics/ photonic integrated circuits?

    i'm looking for the right direction to pursue my work, i need to know weather i should first go for simulations using comsol or FDTD ..else study the experimental work , also i need to know from where i can get the FDTD free one and can anybody  guide me and let me know that where in India i can find labs to go for experimental work ?

    thanku all.

    Alexander S. Solntsev · Australian National University

    Depends on whether you are better with programming or hands-on experimental work. Overall I would recommend starting with experiments, since in my experience experimentalists appear more in demand compared to numerical modellers (however keep in mind that it might change in the future). This might be a good place to start: http://nanophotonics.iitd.ac.in

  • What is the optimum time required for rat brain fixation after trans-cardiac perfusion?

    For H&E staining and immunohistochemistry studies of brain tissue, we performed trans-cardiac perfusion with 4 % formaldehyde and then post-fixing in 4% formaldehdye for 24 hours. But I could not get good sectioning, tissue separated from paraffin. Is it related with perfusion time or anything else?

    Muhammad Shoaib Akhtar · University of Health Sciences Lahore

    Just remember penetrartion time of 4% formaldehyde. It is 1mm/1 hour. So co-relate kindly it with the size of rat brain. However, I think 4% formaldehyde is not suitable to fix brain and its efficiency is not appropriate in brain biopsies.

    So look to some brain suitable fixative and fix brain in that.

  • Abdelhalim Zekry asked a question in LTE:
    How can the channel capacity be equalized along the radius of the cell in LTE?

    The channel capacity decreases with distance from the base station as a consequence of the the decreasing of the signal to noise ratio in LTE systems. At the cell boundary, normally Bpsk modulation is used while the order of modulation may increase to 64 QAM or more near the center of the cell. This means a bandwidth efficiency increase of about five times from the cell boundary to the cell center.

    So, the subscribers at the cell boundary are better served than those at the cell boundary. My question is how would the channel capacity could be equalized among the the distance from the cell center? 

  • C. Jellinek added an answer in Methadone:
    Combination of methadone and morphine?

    Methadone maintenance is in the patients perspective a quiet "boring" drug. We think that not only cocaine is often used in high dose maintenance, but also alcohol (carbonic acid + alcohol = "cick"). My question is:

    Does anybody know wheher there are combination maintenance programs with fast acting morphine in daytime and low methadone for the night?

    regards

    c. jellinek

    C. Jellinek · aid berlin

    Devin,

    yes, you are right, we still have no answer to the original question!

    we allready know, that slow releasing morphine is as effektiv, als methadone (1). In individualiced treatment it should be possible to combine the pharmacologig effekts of different opiats including sr-morphine and diacethylmorphine (2).

    In my opinion its not a question of ideology, but of evidence. So I think we should try new ways and combine opiats for patients who do not profit from the treatments we allready established.

    All the best!

    Chaim

    (1) Beck T. et al: Maintenenace Treatment with slow releasing oral morphine: a roandomiced cross-over, non-inveriority study versus methadone. Addiction, 2013, 109, 617-626

    (2) Gschwend P: Heroingestützte Behandlung in der Schweiz, Diss. 2003

  • Jitendra kumar saini added an answer in Cellulase:
    Why does the specific activity of my enzyme decrease at each step of purification?

    Can anyone provide possible reasons why the specific activity of my cellulase (from bacteria) keeps reducing after each step of purification? So far, the crude enzyme has the highest activity after ammonium sulphate precipitation and dialysis.

    Jitendra kumar saini · Indian Oil Corporation Limited

    no the substrate does not influence this loss of activity, rather it is your purification system e.g. the matrix etc that are actually inhibiting.

  • Twyla Ostrowski added an answer in Logic:
    What is the origin of the popular belief that evil deeds are done by evil people?
    The idea that evil acts can only be committed by evil persons seems to me to be illogical, a medieval, primitive, prescientific delusion. Yet it forms the bedrock of our legal system, and is why our prisons are full of the mentally ill. It is also uncritically held by the media. For example, the front page headline in yesterday's London Evening Standard reads "40 cyclists killed -- 4 drivers jailed". Something evil has happened, therefore this must be the lorry drivers' fault. Is anyone willing to defend this popular belief, this inexorable deduction?
    Twyla Ostrowski · Walden University

    I feel that 'evil' is often confused with illness. A person who is not whole with their abilities to understand cognitive function may use their own frustrations to act in a violent manor. I also believe our criminal justice system is far behind ion understanding the difference.  I have myself been a victim of an evil violent crime that I still hold the black and clue marks from this very holiday season. The criminal justice system has however not understood that these individuals are ill and continue to make cyber contact via my stolen phone and contact info. I feel we must educate first responders as well as investigators to the difference as well.   I wish I had a better response perhaps its just my concussion.

  • Stephen Grey asked a question in System Analysis:
    What does risk look like in a complex project?

    This is not a simple question. My initial thoughts on the topic can be found at http://broadleaf.com.au/resource-material/what-does-risk-look-like-in-a-complex-project/

    I'd be interested in any ideas formulated in relation to projects. Most of what I can find at the moment can be characterised as 'it all gets very difficult' or systems analysis responses that descend into the sort of detailed decomposition that is more appropriate to complicated but fundamentally predictable systems.

  • Sumit Dhumal asked a question in Chitosan:
    Can anyone suggest me for preparation of chitosan emulsion formulation ?

    Currently i am using chitosan powder, acetic acid. Chitosan powder of 70% and 90% deacetylation. i am getting problems in 10% solution preparation it is not dissolved properly. Kindly suggest me additives to increase solubility.  

  • How to remove cyclicity or diurnal behavior from a time-series dataset?

    Hi all, 

    I have a long time-series data with a clear diurnal behavior (cyclicity). Any ideas, publications or works on how to do it? I'm thinking of a Fourier Analysis, but I wonder if anyone has dealt with this problem before?

    Regards

    Ashraf Afana Afana · Durham University

    Hi Sergei, the rock face in this figure is between 800m and 1500 m. However, with the instruments that we use, we also have data with 3500-4000m. for this case I have the air pressure records. Do you suggest that air pressure could provide more highlights about cyclicity that temp?

  • Barbara França Dantas added an answer in Drought:
    When and where do we use the term drought and water deficit stress?

    Quite often it is said that if we write studies to understand the drought tolerance of coconut or some other crop it is not correct. Please clarify this.

    Barbara França Dantas · Brazilian Agricultural Research Corporation (EMBRAPA)

    Dear K.B.Hebbar,

    I usually used drought as any  lack of water for seed germination, no matter how. But an important scientist once explained me that if my experiment was  with water restriction due to PEG or other osmoticaI should use the terms "osmotic stress" or "water deficiency", with a preference for the first. Dought stress I should use only in experiments in wich I really dont irrigated the plant, seedlings or even seeds. 

    Hope it helps.

  • Why do my cell not adhere to the culture dish after?

    I tried to obtain bone marrow-derived mesenchymal stem cells of mice. However stem cells don't adhere to the culture dish after the first passage. Maybe anybody faced this problem.

    Daria Kuznetsova · Nizhny Novgorod State Medical Academy

    Thank you for all advises! I'll try to use the proposed methods. 

  • Ivan Kanchev added an answer in Avidin:
    How can I reduce background on liver tissue in immunohistochemistry?

    I am currently optimizing a new biotinylated primary antibody. It works great on brain tissue but I am encountering background with liver tissue. I am using avidin, biotin and hydrogen peroxide as blocking agents. Is there something else I should use to pretreat these liver tissues? Any help would be greatly appreciated. Thank you for your time.

    Ivan Kanchev · Institute of Molecular Genetics AS CR

    Polymer systems and you avoid biotin block.

    I use only them after their invention. Also blast the immunogen for a secondary binfing.

    Be aware that Fab' fragment of an antibody binds to an epitope max. 25 amino acids

  • Bruno Daucé added an answer in Consumer Behavior:
    Is there anybody who can remember the name and the author of the book which developed the concept of Moment of Truth before it was used by P&G?

    In 2006, Procter & Gamble announced that they were focusing on the "First Moment of Truth". If I remember well, before P&G, there was a book which developed this concept of Moment of Truth but I can not remember it. Any idea?

    Bruno Daucé · University of Angers

    Great ! Thank you !

  • Henni Ouerdane added an answer in Condensed Matter:
    Can Anderson Hamiltonian for metals be valid for semi-metals?

    Can be Anderson Hamiltonian for metals valid for semimetals? How can we use slave boson approximation for slave boson methods?

    Henni Ouerdane · French National Centre for Scientific Research

    Dear Igor,

    I cannot agree with the statement "I'd avoid using slave-boson technique anywhere [...]". Using the functional integral formalism to go beyond perturbation theory for strongly correlated systems, the slave-boson formalism (in the radial gauge) is quite a powerful tool. It was shown analytically for a two-site system described by the single impurity Anderson model, and the analysis may be numerically extended and applied to larger systems with no particular difficulty.

    To support my statement, more details may be found in two of my papers: 1/Nuclear Physics B vol. 785, 286 (2007); 2/ Europhysics Letters, vol. 82, 31001 (2008) and references quoted therein. 

    Sincerely,

    Henni

  • Subhojit Sen added an answer in Cancer Cells:
    What would you add or change for a complete list of the hallmarks of cancer?

    The concepts published on the hallmarks of cancer (Hanahan D, Weinberg RA, The hallmarks of cancer Cell. 2000 Jan 7;100(1):57-70) and its update (Hanahan D, Weinberg RA, Hallmarks of cancer: the next generation Cell. 2011 Mar 4;144(5):646-74. doi: 10.1016/j.cell.2011.02.013) have been very influential in forming our ideas about the nature of cancer and reasonable approaches to improved interventions. Do these published hallmarks completely capture current ideas or would you add or change them from your results and understanding?

    Subhojit Sen · Centre for Excellence in Basic Sciences

    I personally work on Cancer Epigenetics of how environmental factors can change the normal/stem cell epigenome towards a more cancer specific epigenome, and have good reason to strongly support the notion that Epigenetics needs to be included. (or Environmental factors other than inflamation as well). Secondly, wound healing and mechanical stress stimuli or general Stress stimuli probably can be more of an inclusive term towards various environmental insults. 

  • Stephen Grey added an answer in Stock Markets:
    How can I formulate a questionnaire on Stock Markets Behaviour?

    I am interested in the kind of questions I can ask stock brokers and investment bankers. Most of the research on stock markets behavior is mainly secondary data form but I also want to have some primary data on this. Contributions will be appreciated.

    Stephen Grey · Broadleaf Capital International Pty Ltd

    I haven't read the article at the ink above in detail but I have dipped into it and read the section on method.

    This seems to illustrate the point about preconditioning the analysis. The statement "For simplicity, four broad dimensions are identified for measuring investor’s behavior." means that the researcher can only discover characteristics associated with these four dimensions.

    I have no way of knowing if there were any really interesting factors at work outside of these four themes but the researcher probably doesn't know either.

  • What is a suitable method for screening for mutations?

    We sequence patients DNA in order to detect the different mutations associated with the disorders; if it is simple gene with few exons and small number of patients then it is feasible to use either capillary or next generation sequencing, but if we have a complicated gene with many exons and many patients, it is more feasible to do mutation screening before sequencing. Because there are many mutation screening methods, the question now is, what is a suitable method for doing mutation screening which is accurate, fast and cheap?

    Muhammad Shoaib Akhtar · University of Health Sciences Lahore

    Restriction Fragment Length Polymorphism is always convenient, efficient and economic way to screen out mutations. Try it please. Hope you will get satisfactory results.

  • The DSM-V offers "suicidal behavior disorder" (p. 801) as a "condition for further study" that seems to medicalize suicide attempts. Thoughts?
    The DSM-IV cited suicide as a symptom of some psychiatric disorders. Until now suicidality has not been characterized as a disorder itself (though it could loosely "fit" the disease model, i.e., signs, symptoms,markers, course or process, etc.). Early in the DSM-V's development there were allusions to having suicidality become a new Axis-VI. Given the pervasiveness of suicidal behavior among individuals with serious mental illness that may have been useful. However, I am not sure what utility "suicide behavior disorder" has in terms of diagnosis, treatment, prevention, or research. Does the APA expect researchers or theorists to give this new disorder "further study" or will clinicians take on that task?
    David Sánchez-Teruel · Universidad de Jaén

    I have read all the previous post, and I think all of you. Bring something to teach me or something with which I agree. However, to date still the international diagnostic manual (DSM-V and ICE-10) too are influenced not only by the policy as Jennifer says but also for the economy. This makes many aspects of suicidal behavior that remain unanswered are invisibilicen. In particular, the urgent need for WHO to invite all countries to gather epidemiological data on suicide attempts, and not just about suicides. However, this seems, to date, impractical because it would set off alarms about the blindness of the public health systems in many countries that are designated as "welfare" for other so-called "underdeveloped". The growing importance of global macroeconomics in the prevention of suicide remains a handicap for researchers and scientists, and international diagnostic manuals are still dotted with these macroeconomic influences, which makes me cautious about the results provided by these operating diagnosis. (I apologize for my low English)
    regards
    David

  • Hossein Hemmati asked a question in DVT:
    What is your anticoagulation strategy to prevent DVT after endovascular treatment of traumatic high flow AV fistula in lower limb?

    I treated a 28 year old woman with high flow distalSFA high flow traumatic AV fistula with covered stent and veins were significantly dilated.

  • Tayebe Roshani added an answer in Fertilizers:
    Can anyone help with the fertilizers amounts that would help making a fast season for carnations?

    I am searching for reviews about the timing and amounts of fertilizers with carnation plants.
    Thanks

    Tayebe Roshani · Tarbiat Modares University

    Hi,

    Please see the link and download a file.

    I hope this file helps you.

    Good luck

  • Calcium chloride dihydrate precipitates after autoclaving. Could this affect bacterial transformation when using the Calcium chloride method?

    I am preparing competent cells using calcium chloride to transform Jm109 Ecoli with pET32a vector. Due to lack of facilities i'm unable to use electroporation or any other techniques. After transformation i did not get any colonies on LB-amp plates. Could any one suggest me where i could have gone wrong. I use 100mM calcium chloride.

    Subhojit Sen · Centre for Excellence in Basic Sciences

    If your Calcium chloride precipitates upon autoclaving (which shouldnt happen), the pH of your solution might be more acidic. Check the pH of the distilled water you are using, preferably neutralize it before or after making your solution and try reautoclaving it .Precipitation of CaCl2 clearly would affect the efficiency of your actual transformation. 

    The other option I would strongly suggest you to do, is to use DEIONISED water if available, if not - make your final transformation buffer with unautoclaved stock and adjust to required pH and then FILTER STERILIZE using a syringe antibacterial filter (at least 0.22 or 0.44 microns). The latter is what i routinely use - and it always works. 

    Lastly to increase your transformation efficiency follow the INNOU PROTOCOL for CaCl2 transformation, you can google it up. If you cant get a hold of it, inbox me. 

    Goodluck

  • Gisela Vaz added an answer in Mitochondria:
    Does anyone know how to solve a mitochondria staining problem?

     i can't get well mitochondria staining pattern when staining my cell line with Mitotracker Red CMRos from Invitrogen. Does anyone have any solutions?

    Gisela Vaz · University College Dublin

    Why not try TMRM? I use this routinely and it has never failed. Otherwise do a dose/stain trial. Start with 100nM and go up in serial dilutions, use a 96 well plate or something small so you are not using too much dye. Also it could be your fixation. Try imaging the stained cells live and then fix. image them again once fix. You should be able to find the problem. Confluency of cells should not affect the stainning.

  • Hanno Krieger added an answer in Sarcoma:
    Why does heart rarely develop cancer?

    Primary and secondary cardiac tumors are very rare.

    Hanno Krieger · retired from Justus-Liebig-Universität Gießen

    Dear Lawrence, you are totally right. Helicobacter pylori, human papillomavirusses...

    Apart from your transport argument, one of the organs with maximal blood supply is the heart. And blood transports too.

  • Davood Shaghaghi asked a question in Type Systems:
    How can I design a back stepping controller ?

    Hi every body,

    How can I design a back stepping controller for this system? h1 and h2 is states of system and q is input.

    Because, in Khalil's book, design is said for specific type of systems.

  • Parth Sarathi Mahapatra added an answer in PM2.5:
    Which are the best long term passive sampler methods for outdoor air pollutants (Gaseous & PM)?

    We need to monitor air quality in term of SOX, NOX, PM2.5, PM10 and total VOCs pollutants for 2 years with seasonal resolution.In your opinion what is the best feasible option for passive monitoring seasonal concentration (3 month continuous measurement) of SOX, NOX, PM2.5, PM10 and total VOCs?

    Parth Sarathi Mahapatra · Institute of Minerals and Materials Technology

    I think you can look for envirotech instruments, polltech instruments. They provide a wide range of particulate and gaseous samplers.

  • Mina Ketan Parida added an answer in Parity:
    Why does the parity need to be violated?

    There is parity violation in the weak interaction especially. But the actual cause is still hidden.

    Mina Ketan Parida · Siksha O Anusandhan University

    The parity violation is an experimental fact  showing excess of left-handed electron emissions in the beta decay of  $CO^{60}$ nucleus compared to right-handed electrons. Also it appears that this parity violation is a monopoly of weak interaction.  Till now two satisfactory theoretical  answers have been provided in favour of such parity violoation. (1) Left-Right Symmetric Gauge Theory , (2) Mirror Symmetric Gauge Theory,  based upon extensions of the standard gauge theory.