Q&A

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  • Tillmann Krauss added an answer in Ultraviolet Rays:
    Please anyone suggest me what is minimum thickness of aluminium that will protective from Ultraviolet rays?

     For working in Optical lithography lab(exposure to ultraviolet rays) i need UV rays protection suit .i did not found. now i m thinking to sew aluminium foil on ordinary clothes.. so  please anyone suggest me what will be minimum thickness of aluminium  that will protective from Ultraviolet rays? and will it be good choice?

    Tillmann Krauss · Technical University Darmstadt

    Are you talking about standard UV lithography systems for wafer processing (193i line)?
    Do you have broad band UV measurment system to calibrate your processes? If yes, you can start to measure a bit around your litho system.

    Something like this for example: http://www.amazon.de/UV-Licht-Messger%C3%A4t-3-1-2-stellig/dp/B006L6S45U

    Normally, a clean room suite will protect you from UV-light and the exposure level is below direct summer sunlight. But you should wear UV-protecting googles if you can directly see into the source somehow.

    Best,
    Till

  • Sruthi Sam added an answer in Primates:
    How can you image the ciliary muscle (not just ciliary body) in vivo?

    I want to see a well-delineated ciliary muscle by imaging in live primates, just like how muscles look in a musculoskeletal MRI. Any suggestions will be appreciated, thanks.

    Sruthi Sam · Case Western Reserve University School of Medicine

    Thanks for idea Fokko Pieter Wieringa. OCT uses IR rays which usually donot cross the iris making it a challenge to image the ciliary body. I am looking for something that would show the ciliary muscles inside the ciliary body. Appreciate your response.

  • Vincent Ogunlela added an answer in Proline:
    Is it possible a constitutive proline synthesis in perennials crops as a strategy to avoid damage?

    Hi all,

    We know that proline is related to stress and there are many possible roles to proline on plants. However, I am wondering if high levels of proline in plants with no significant stress could naturally occurr. Perennial plants experience stressful conditions many times during their lives, many times in repeated cycles, then would it be possible produce proline prior another stress time to avoid damage? What do you think?

    Vincent Ogunlela · Ahmadu Bello University

    Proline synthesis naturally occurs in perennials in response to stress occurrence. The common type of stress inducing proline synthesis is that of low moisture stress i.e. drought. During conditions of no-stress, it is not likely that proline synthesis will normally occur. It therefore implies that the higher the proline synthesis, the higher is the plant's resistance to stress.

  • Peter T Breuer added an answer in Linear Algebra:
    Why the direction of eigenvectors turn towards outliers?

    I need a simple explanation based on linear algebra

    Peter T Breuer · Birmingham City University

    You won't get one. Try using common sense ... ask yourself what running a mix of eigenvectors through the transform does to them, by definition. That's right: the coefficient of the eigenvector with the biggest eigenvalue is multiplied by the biggest value, so grows relative to the others.

    Repeat, ad nauseum :-)

    Was that hard?

  • How do you successfully isolate prostate primary epithelial cells without using the cell sorting method?
    see above
    Henry Withers · Roswell Park Cancer Institute

    Hi Zeinab,

    I'm happy to hear the protocol worked for you.  I have not personally looked at genomic stability or colony forming potential with mouse prostate cells grown with the feeder/ROCK system; however, I know the authors of the referenced paper above karyotyped both late passage prostate and breast cells and found that they maintained normal chromosome structures.  I would guess that the mouse model you harvested your prostate cells from would play a large role in determining the colony forming potential of the cells (e.g. wild type prostate cells vs. mouse prostates with tumor suppressor deletions or oncogene overexpression).  Good luck!

    Best,

    Henry

  • Sarmed Salih asked a question in Abaqus:
    Is any can help on UMAT subroutine cohesive zone model in ABAQUS?

    Hello all

    I'm working on cohesive zone model and I want to us ABAQUS the finite element solver, but I need Implement a Umat for the cohesive model I want to use.

    The problem is I'm new for ABAQUS and finite element simulation. I have checked the user subroutine manual and seen some Umat, but non of them is for cohesive model. I now that in the Umat I have to give the material Jacobean matrix and update the stress. the question is do ABAQUS need the Jacobean matrix or it just to update the stress, so if I have simple linear relation between the stress and the strain, can I just update the stress according to the relation that I have and not derive the Jacobean.

    If any one have an example of Umat for cohesive model that will be really helpful, or if any one can give any advice I will really be grateful.

    Kind Regards,

    Sarmed

  • Tim White added an answer in Silver Nitrate:
    How can we measure the amount of chlorine in brine?

    One way to measure chlorine in brine except for the precipitation of silver chloride by silver nitrate.

    The first thing I would try would try would be a DPD method published by the Standing Committee of Analysts.  You will need to verify the performance in a standard brine solution but I would be surprised if you could not get it to work to distinguish free chlorine.

  • Michał Błażej Ponczek added an answer in Buffer:
    Does anyone knows how pH can affect in Western Blot assays?

    I usually perform sample lisys with a lisys buffer pH 8.0, but i forgot to adjust the pH when I prepared a new buffer, and that was pH 11.0. When i performed Western Blot, this protein wich has to be bettwen 55 kDa and 70 kDa, was shown in 100 kDa. The same happened with another protein wich had to appear around 130 kDa and was shown in 190 kDa. Does anyone knows something about it? Thank you guys.  

  • Darren Naish added an answer in Predatory Behavior:
    What use, if any, did hands play in manraptoran predatory behavior?

    I know that in years past, it has often been suggested that predatory maniraptoran dinosaurs (mainly troodontids and dromaeosaurids) used their forelimbs to catch food. Indeed, Ostrom originally suggested that flapping behavior began as an extrapolation of the prey catching stroke. However, now that we know more about the anatomy of these predatory dinosaurs, specifically that many forms had large secondary and primary feathers on their arms and were incapable of pronating their hands, I am having a hard time seeing how the forelimbs could have been of any use in predatory behavior. There doesn't seem to be any way that they could have been rotated to grab prey, nor slash at conspecifics or larger prey items. Yet there has to have been some function for having flexible clawed digits in maniraptorans, as nearly all maniraptorans have well-developed hands, and indeed many early birds still had well-developed digits.

    Darren Naish · University of Southampton

    Hi - have you seen Phil Senter's papers on this very topic? Even with a fully feathered, pronated hand, it seems that dromaeosaurids and others could bring the hands together to clutch prey. 

  • Murat Sertkol added an answer in Nanospheres:
    Why is a kink appearing at around 160 K in the M-T curve of Fe3O4 nanospheres?

    I have prepared Fe3O4 nanospheres using  hydrothermal process. The nanospheres have a layer of PVP coating on the surface.The size of the nanospheres were found to be around 200-300 nm while the individual nanoparticles assembled in the nanospheres have a diameter of 5-7 nm. The M-H curves shows the signature of ferromagnetism. But in the M-T curves I found a kink around 160 K. And the kink deepens if I increase the magnetic field. Initially I thought that the kink might be due to Verwey transition but then Verwey transition occurs at around 120 K. Can anyone give a possible explanation to this?

    Murat Sertkol · Istanbul Technical University

    In addition with Dr. Irene; TEM should reveal the distribution of particles and they can be in different sizes. Such magnetic behaviors may result from two sublattices. It it important that your sample has single phase and does not have impurity. If some structural analysis like XRD shows you a second phase, this may trigger the formation of magnetic moments at a different temperature.

  • Dirk Werling added an answer in Tuberculin:
    What are the immunological actions of Tuberculin PPD?

    Does anyone have experience in using them as Ag in DC-T-cell culture?

    Dirk Werling · Royal Veterinary College

    Thanu, if you use PPD in a DC-Tc (CD4) assay, you can stimulate them to proliferate and secrete IFNg. The response you get is dependent on timing (as in pulsing of APC with PPD), the dose, cell numbers (on both sides) etc. 

  • Giulia Amico added an answer in Primer:
    Can you confirm the results of my MPLA experiment by Long PCR?

    Hi everybody! I am carrying out an MLPA experiment and I have to confirm my data.

    I have chosen Long-PCR approach to confirm the presence of deletions and to define their limits, but I have some doubts: can I achieve my aim if the PCR primers are designed upstream and downstream of the first probe and of the last probe related to the deleted region, respectively?

    For example, the deletion encompass the exon 2, 3 and 4: the primer 2f is designed upstream of the probe number 2 and the primer 4r downstream of the probe number 4. So, using this conditions am I able to amplify and sequence the correct region to analyse the deleted region or I have to use the primer 1f and 5r?

    I hope it's clear...I am looking forward hearing from you!

    Giulia Amico · IRCCS Istituto G. Gaslini

    Thank you Daniela, you're so kind!

  • Ivan Kanchev added an answer in Horses:
    How do you proceed with a horse retina for pathohistology investigation?

    Does anybody have any experience with histology of horse retina?

    How do you fix this tiny structure before cutting it?

    Thanks!

    Ivan Kanchev · Institute of Molecular Genetics AS CR

    I will stick to Davidson's fixative or modified Davidson's for IHC.
    See this article:
    http://tpx.sagepub.com/content/30/4/524.long
    Надявам се да съм помогнал, макар и малко :) Поздрави на всички от вет. патология в Стара Загора

  • Extra protein bands after recombinant protein purification-any thoughts?

    When I overexpressed my recombinant protein in E.coli, i found multiple proteins overexpressed, and became more clear after protein purification using talon metal affinity resin column (Purified- P1-III lane)

    I don't know if the extra bands due to proteolysis of my protein or not.

    I tried different sonication protocols (on ice) to disrupt E.coli cell wall (5 sec x 10 cycles and 15 sec x 10 cycles-80%power-1 mint pause after each cycle).


    Please check the attached picture.

    Rossana Garcia · University of Havana

    in case of being proteolysis of your protein, you can try adding a coctel of protease inhibitors to avoit such degradation and compare the profiles of both samples in SDS-PAGE. This is maybe easier than trying to have an antibody to check if the bands are due to degradation.
    Anyway, it is very rare  that all bands are very strong which is not usual if they are due to degradation.

  • Martha Berdugo added an answer in Language Learning:
    Do you feel that you know CALL/MALL best practices?

    Computer Assisted Language Learning and Mobile Assisted Language Learning is popular and many studies have been published about them, but I am not convinced that faculty have the resources to know the instructional design best practices.  

    I am NOT asking what you think the best practices are, but whether you think that the academic literature has sufficiently defined best practices for instructional design.  Why or why not?

    Martha Berdugo · Universidad del Valle (Colombia)

    Hi. This issue is particularly relevant in several countries like Colombia where there has been important government investment to provide schools with tablets. There are also several programs intended to train Math, Science and Language teachers to effectively integrate ICT in the classroom and the school. There is much need to work on curricular integration and apps dessign for mobile devices.

    Suggested work and litterature on this particular issue will be welcome.

  • K. Sudhakar added an answer in Spirulina:
    Can we use the biomass ( fresh spirulina) in production of industrial foods enriched with spirulina? What foods or drinks ?

    I woud like to use food products enriched with spirulina platensis for patients with diabetes, metabolic syndrom and etc so that each patient intake 5 to 6 gr or more  spirulina daily .I think vegetable puree is suitable

    K. Sudhakar · Maulana Azad National Institute of Technology, Bhopal

    Yes.It can be mixed with fruit drinks in an proper amount

  • Can anyone help with SEM image detail interpretation?

    Can anyone help with  SEM image detail interpretation, for example:

    what is the meaning of WD ?

    what is the meaning of Det:Sec ?

    what is the meaning of Det:in Beam?

    what is the meaning of HV:13.0 kv?

    Ehsan Soheyli · Arak University

    Thank you Mr. David Barbier for such a useful link

  • K. Sudhakar added an answer in Solar Cells:
    How do you define the "Active Area" of sensitized solar cells?

    I would like to know what the active area of DSSCs is? Is it the total area of the working electrode or do the researchers use a "photomask" with a specified area to define the active area during characterization? 

    K. Sudhakar · Maulana Azad National Institute of Technology, Bhopal

    Normally ,Total area of the working electrode has to be used while using the active area.

  • Md. Lutful Amin added an answer in Amines:
    How might one conjugate two materials to amine functionalized nanoparticles?

    I have to conjugate two materials to amine functionalized nanoparticles. Both materials have amine and carboxyl groups. I thought about conjugating the first material by amine-NHS reaction (the first material has NHS group) and the second material by COOH-amine using EDC. However, after conjugating the first material, how will I ensure that the second material will not attach to the amine group of the first material?

    Md. Lutful Amin · Stamford University Bangladesh

    Thanks all for your valuable comments. )

  • How can we control Isopoda fish parasites in open lakes?

    Some culturists collect feral fingerling marine fishes to be cultured. The isopods have been transferred from feral fish to the farmed fish or to fishes in open lakes.

    I need to know how to control this mistake in transport in new situations.

    Nahla Ramzy El-Khatib · Animal Health Research Institute

    Thank you for your interest, but the parasite transport to a large natural closed lake more than 55 000 acres , you mentioned treatment is difficult to apply.

  • In the role of Human Resource manager, whether management graduate or psychology graduate is more effective?

    In managing human resources, who is more effective: those trained in management or those trained in psychology? Is there any such research work conducted so far?

    I think knowledge in psychology gives you ability to know what your employees are but not how to maintain and train them in terms of your business development. That is where MBAs score. So knowledge of Management is also important indeed in order to achieve any organisations goal.

  • Gregory J. Mccabe added an answer in Snow:
    How would you identify the snowmelt period in a streamflow regime/signal, if you only have daily streamflow values available?

    On catchment scale the seasonality of a streamflow regime is controlled by and composed of different water contributions to the stream (such as glacier melt, snow melt, rainfall / event water, groundwater etc). The streamflow regime is also influenced by evapotranspiration etc. What would be your first idea if you only have streamflow data/signal available to identify the snowmelt period (during the year) and/or to estimate the snowmelt contribution according to yearly discharge sums? My focus is on humid catchments on a meso- or regional-scale (lets say 10 to 1000 km^2 with 50yr streamflow data). All suggestions/ideas/methods are welcome (perhaps also what kind of additional data would be helpful to justify your approach, e.g. stream temperature, groundwater level, isotope data....)!

    Gregory J. Mccabe · United States Geological Survey

    I think that Mike Dettinger (USGS, mddettin@usgs.gov) has done this type of an analysis. He is who you should contact.

  • Alexander Streng added an answer in Turtle:
    Does anyone have an idea what a highly expressed, 30.000 da protein in turtle (T.scripta) skeletal muscle could be?

    See above

    Alexander Streng · Maastricht Universitair Medisch Centrum

    I am guessing you are looking at Troponin T.

    That protein is highly expressed in muscle tissue and is about 30-35 kDa.

    But it is impossible to be sure without any identification experiments. Try blotting it with a skeletal troponin T antibody. Troponin T is very well preserved in its centre, so you may get lucky. Your best bet at identifying the protein is to cut it out and do a digest+mass spectrometry, if you have access to those techniques.

  • Sirwan Rashid added an answer in Essential Oils:
    What is the best way to measure the solubility of essential oils in water?

    I want t o know how much of essential oil will dissolve in water, it is not easy because very small amount will dissolve but my concern is to measure that amount. Thank you for your help

    Sirwan Rashid · University of Leeds

    Thank you for your answer Mr Ravi, but in some articles it is mentioned that some of EOs dissolved but the amount is not reliable 1gm/L water. It is obvious that there some degree of solubilization because of hydroxyl groups presented on the most of essential oil components such as thymol and carvacrol, I ran some experiment which indicating that there is some of the oil fractionated in water but I don not know how much? Thank you again.

  • Julie Mcgrath asked a question in Lipofectamine:
    What are the best methods to stably transfect multiple plasmids into MDA-MB 231 cells?

    Hello all,

    I am trying to stably transfect 5 plasmids into MDA-MB 231 cells using lipofectamine.  I have tried using increasing amounts of lipofectamine ( 6ul-15ul) and 5ug of total plasmid DNA with no success. I am able to transfect 293T cells with this method but not 231 cells. Any tips would help me greatly.

  • Dummy variables creation for a regression model?

    It does not make sense to create dummy var for a var like month, where value of dec (12) can give wrong implication and distorted distribution; but for var like risk ( low, med, high, very high), shall we create dummy var or numeric var with values 0,1,2,3?I want to use these vars for a logistic model.

    Timothy A Ebert · University of Florida

    @Paul

    So I want to hierarchically classify all types of data.

    The first decision is ordinal versus categorical. In this case the categorical data are things where mathematical operations do not apply. For example color. Red+blue = ??? Numerically I can convert red to 700 nm, and blue is 450 nm, so the sum is 1150 nm, which is infrared. Purple may be what we see, and it is possible to model the result mathematically, but adding and subtracting colors doesn't seem to work with any of the standard mathematical principles (inequalities, distributive laws of addition, and so forth). One could convert the colors to their wavelength equivalent, but in our perception of red there is nothing that constrains a relationship Red>Blue.

    If you have ordinal data then there are subtypes of ordinal data. The most common are integers and real numbers. There is also a type of categorical variable where a specific ordering is clearly present. The Likert scale variables go here. Dummy variables would also go here: e.g. nitrogen fertilizer at low, medium, and high levels. Your example of surrogate variables would also go here. That example was enlightening as I would usually use gender as an example for the preceding paragraph.

    Did I get this right?

  • K. Sudhakar added an answer in Drying:
    Methods for measuring root biomass?

    I can't find good methods for doing this. I'm assuming the roots need to be weighed both wet and dry the same as with aboveground plant material but I have no idea the drying temperature and for how long? Also, methods of substrate removal from the roots? 

    I'm not looking for the weights to represent insect feeding or nutrients, etc. I just need this information to confirm that root masses between plants are the same. 

    Thanks in advance! 

    K. Sudhakar · Maulana Azad National Institute of Technology, Bhopal

    Thank you Susantha Jayasundara for sharing the pdf file.

  • Robin Effing added an answer in Social Media:
    Can anyone suggest me a scale that measures the effect of Facebook on political elections?
    How do political candidates use Facebook?
    Robin Effing · Saxion University of Applied Sciences

    See related work on http://www.socialpower.nl/cms/publications/

  • Are there any survey articles regarding state-of-the-art applications where WSNs and IoT are applied?

    I am looking for an article or any possible material that can guide me to the current state-of-the-art applications/projects proposed and applied for WSNs and IoT. 

    It's not that difficult to find solutions and protocols/frameworks for these technologies. However, new applications and ideas where these technologies are utilized are not that easy to find. 

    Arpan Pal · Tata Consultancy Services Limited

    PL. look at this publication for a state-of-art requirement for IoT platforms.

  • Murat Sertkol added an answer in Ultra-High Vacuum:
    Why is Bismuth considered bad for ultra high vacuum?

    What about other materials with high vapour pressure in room temperature (eg. In,Sb,Sn,Pb)?

    Murat Sertkol · Istanbul Technical University

    Dear Dr. Carlos, is that the unique reason for usage of indium?

    Thanks in advance.