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  • Ana Maria Oliveira Battastini added an answer in ATP:
    Energy in breaking bonds [ATP and ADP]?

    ADP + Pi + Energy => ATP

    is the formula we know about forming ATP and vice versa in forming ADP.

    While reading a text book on cell and molecular biology, I encountered a section about forming and breaking covalent bonds. The textbook explained that forming covalent bonds releases energy. On the other hand, breaking covalents requires the released energy to be absorbed.

    But in the case of forming ATP, energy is required to form the bond between an extra phosphate with ADP to form ATP. Furthermore, the breakdown of ATP to ADP releases energy.

    It seems like the mechanism explained in the textbooks is controversial in the case of forming and breaking down ATP. What am I missing on?

    Ana Maria Oliveira Battastini · Universidade Federal do Rio Grande do Sul

    I don´t know if I understood your question, but I think that the hydrolysis of high energy nucleotides is quite diferente from the concept that "about forming and breaking covalent bonds". You can find a complete explanaton in the Biochemistry text books, such as Lehninger - Principles of Biochemistry (Nelson and Cox, Third Edition, at page 500 you can find a very good explanation  about the free energy changes of ATP hydrolysis.

  • Azzam K Almosallami added an answer in Elementary Particles:
    Do photons interact with gravitons?

    The graviton is a hypothetical elementary particle that mediates the force of gravitation in the framework of quantum field theory. If it exists, the graviton is expected to be massless and must be a spin-2 boson. The spin follows from the fact that the source of gravitation is the stress–energy tensor, a second-rank tensor. But by no means is it universally accepted.

    http://www.fnal.gov/pub/today/archive/archive_2012/today12-10-19_NutshellReadMore.html

    But there are many articles about the interaction between Photon and graviton or graviton-photon scattering.

    http://journals.aps.org/pr/abstract/10.1103/PhysRev.128.2414

    http://journals.aps.org/prd/abstract/10.1103/PhysRevD.91.064008

    How can graviton's mystery be solved?  Should graviton be detectable or like photon (same as photoelectric effect) be able to explain the physical phenomena?

    Azzam K Almosallami

    Dear Hussien,

    Now everything becomes clear, in case of Pound and Rebka experiment, the measurement was happening in two fixed  points at constant radius from the center of mass in gravitation field, and there is no change on the radius. In this case each point is considered as an inertial frame of reference, because there is no change in the radius from the centre of mass. These two point are localized and fixed. In this case the group velocity and the phase velocity are equal, and time dilation are given according to t=t'(1-GM/c^2r) which is depending on the gravitational potential according to my equivalence principle. 

    For a free, non-relativistic quantum mechanical particle of mass m, we have
    E(k) = h(bar)ω(k) = h(bar)2k2/2m

    Now for Light bending by gravity and the precession, the dispersion is not linear because of motion under gravitational and changing the radius from the center of mass during the motion. So even if we start with a fairly localized “particle”, it will soon loose this localization. In this case the group velocity is not equal to the phase velocity. 

    We can calculate the group velocity for this dispersion as
    vg =∂ω(k)/∂k =h(bar)k/m
    and this is perfectly consistent with the movement of a semiclassical particle for
    which the momentum is p = h(bar)k and the group velocity thus p/m = vg. In this case the classical velocity is not the phase velocity, it is the group velocity which accounts now exactly the precession, the light bending by gravity, Shapiro delay, the Pioneer anomaly. Now everything becomes clear and very simple.

    It was really very complicated and confusing problemmmmm!!!!

    Now when physicists proposed the graviton of spin 2 they were confused by the phase velocity and the group velocity. In fact in case of Pound and Rebka experiment t'=(1-GM/c^2r)t that is right because of the phase velocity equals to group velocity and equals to classical velocity, That is because the experiment done in fixed localized points in space on gravitational field where equivalent to inertial frame of reference. In case of light bending by gravity, Shapiro delay, and precession, there is a motion in gravitational field which is depending on the radius from the center of mass, and the radius is changing by the motion. In this case the group velocity is not equal to the phase velocity, and the classical velocity is equal to the group velocity not to the phase velocity.  In this case the group velocity gives the movement of a semiclassical particle for which the momentum is p = h(bar)k and the group velocity thus p/m = vg. In this case the factor GM/c^2r must be multiplied by factor of 2 depending on the group velocity which equal to the classical velocity. Because of that Shapiro delay, precession, and light bending by gravity can be solved according to t'=(1-2GM/c^2r)t depending on the group velocity. Now we understand how physicists proposed graviton of spin 2 mediates gravitation. They were confused by the same problem, and now it is solved completely. Thus there is no graviton, it is photon!!!!!

  • Lau Xz added an answer in Green Fluorescent Protein:
    Can someone share me how I can improve transfection efficiency of GFP?

    I want to transfect the GFP into the mouse adipose MSC cell, but I tried that serval times by Monster Green® Fluorescent Protein phMGFP Vector,promega. After sorting by FACS, transfection efficiency is less then 15%.. someone can share your experience should I change to another method such like retrovirus or lentivirus? and how about the transfection efficiency?

    Thanks!

    Lau Xz · Hirosaki University


  • Şakir Bor added an answer in Porosity:
    Do aging time and temperature affect the porosity of Aluminum composites?

    ''Heat treatment uniforms the grain structure thereby reduces the porosities'' was written in an article. But I couldn't find any supportive information anywhere else in the literature.

    Şakir Bor · Middle East Technical University

    This rule of thumb is applicable at the early stages of sintering where the geometricaly present pores are more than few, usually even more than 10, percent because of reasons that you can find in the first few 10 pages of any sintering book. See wikipedia. At smaller pore fractions the process becomes too, too slow. Such enormous slowing down is observe also in grain growth.

    Since these are simple constant composition diffusional process, its (pore fraction) time and  temperature dependence must be something like:

    squareroot(time) * exp(-1/T)    and its rate mıst be proportional to:

    squareroot (1/time) * exp(-1/T)

    The temperature need not to be as high as 2/3Tm(K), only 1/3 Tm(K) may be sufficient with correct pore fraction.

    Regards

  • Azzam K Almosallami added an answer in Riemannian Geometry:
    Why didn't QM and gravitation merge yet?

    I've read in a very interesting paper of Prof. Norbert Straumann

    "Einstein’s impact on the physics of the twentieth century"

     reporting:

    ___________________________________________________________

    In the work of Yang and Mills (1954) GR played no role. In an interview

    in 1991 Yang recalled:

    “It happened that one semester [around 1970] I was teaching GR, and I

    noticed that the formula in gauge theory for the field strength and the formula

    in Riemannian geometry for the Riemann tensor are not just similar

    – they are, in fact, the same if one makes the right identification of symbols!

    It is hard to describe the thrill I felt at understanding this point.”

    (Zhang, 1993, p. 17)

    ___________________

    According to this affirmation the structure of the Macro and MIcro are similar and both follow Geometrodynamics. Why didn't they merge in a unique equation then?

    They definitely individuated a background which allows everything to happen (the ACTION)Higgs field, space-time, but according to the results they didn't manage to describe it well enough yet...  it might be due also to the fact that both of them describe time reversible laws, GRT is a classical deterministic theory... Where is the Arrow of time???

    Azzam K Almosallami

    Dear Robert Shuler,

    I hope to reply to me and I would like to hear your opinion. You tried really to confused me, But I really was completely right in my paper. When physicists proposed the graviton of spin 2 they were confused by the phase velocity and the group velocity. In fact in case of Pound and Rebka experiment t'=(1-GM/c^2r)t that is right because of the phase velocity equals to group velocity and equals to classical velocity, That is because the experiment done in fixed localized points in space on gravitational field where equivalent to inertial frame of reference. In case of light bending by gravity, Shapiro delay, and precession, there is a motion in gravitational field which is depending on the radius from the center of mass, and the radius is changing by the motion. In this case the group velocity is not equal to the phase velocity, and the classical velocity is equal to the group velocity not to the phase velocity.  In this case the group velocity gives the movement of a semiclassical particle for which the momentum is p = h(bar)k and the group velocity thus p/m = vg. In this case the factor GM/c^2r must be multiplied by factor of 2 depending on the group velocity which equal to the classical velocity. Because of that Shapiro delay, precession, and light bending by gravity can be solved according to t'=(1-2GM/c^2r)t depending on the group velocity. Now we understand how physicists proposed graviton of spin 2 mediates gravitation. They were confused by the same problem, and now it is solved completely. Thus there is no graviton, it photon!!!!!

  • Lily Goldstein asked a question in Aseptic Techniques:
    Can anyone tell me what this stuff is in my primary neuronal cell cultures? I have pictures! Contamination? Weird cell growth?

    I culture primary neurons, with conditions that support neuron growth over glia or astrocytes. This problem began completely out of the blue, with no changes to protocol, aseptic technique, media or cell source. We've noticed a problem in the inducibility of activity using Bicucullin A, we’re only getting about 10% of the induction that we used to, at both the protein and mRNA level (sometimes no induction at all). Contamination seems unlikely at this point, as we've tried culturing on plates that support bacterial growth and a wide variety of antibiotics. This is a recurring problem, not just an isolated incident, it occurs each week with a new animal source. The contamination/whatever-it-is does not show up in plates that have been prepared and stored identically but have no primary cells.

    I've attached a picture at 20x of the culture after 12 days of growth. The weird orange-yellow stuff is what I suspect is contamination (or maybe a really unhealthy neuron?) Has anyone run into anything like this before? Any suggestions at all?

  • Louise Wallace asked a question in Peptides:
    A very basic question but how do mimotopes work? I know what they are but what information do you get from the binding of a peptide to a protein?

    I have REPLi-K or REPLi-K/R peptides and we are using them to look at binding to a specific protein? I get data but don't know the exact information it is telling me except that it is a mimotope assay.

  • Waleed M. Sh. Alabdraba added an answer in Wastewater Analysis:
    Does anyone know about the ratio between BOD and COD in wastewater?

    in a wastewater analysis i find the BOD/COD ratio in raw wastewater is 0.76

    but in treated wastewater the BOD/COD ratio was 0.43 , why it different from that of raw wastewater? and which is better in treated wastewater the hight or low ratio?

    Waleed M. Sh. Alabdraba · University of Tikrit

    Dear Iswar

    thanks for your replay

    the wastewater was domestic wastewater

  • Joshua Lee asked a question in Gene Editing:
    How can I distinguish gene-corrected transplanted cells from non-transplanted cells?

    I'm taking cells from mice and correcting the present genetic defect using gene-editing tools, then transplanting the cells back into the original organism. Following transplantation, what are some methods I can use to distinguish gene-corrected cells from non-corrected cells?

  • Miranda Nicolette Smit added an answer in Binomial Distribution:
    How to analyze fatty acid data expressed as percent of total fat?

    I am wondering what the best way is to analyze fatty acid profile data, expressed as percent of total fat. I use SAS.

    When I analyze the proportion of animals sent for slaughter per pen, I use a generalized linear model (proc genmod) with binomial distribution and logit link function. I was thinking of using this for the fatty acid data too. However, these parameters are different, in the sense that the proportion of animals shipped is count data and it is binary (either the animal is shipped or it is not). The fatty acid data is not count data and it is not binary. Could I still use proc genmod, and if so, which distribution and link function should I use?

    Or would it be better to just use proc mixed, either on arcsin transformed data or the untransformed data?

    I would appreciate your insights and thoughts.

    Miranda Nicolette Smit · Government of Alberta, Ministry of Agriculture and Forestry, Edmonton, Canada

    Thank you Ariel!

  • Harith Karunarathna asked a question in KNN:
    How to use bilinear interpolation on 2d axis ?

    In my application i find 4 nearest points on the grid (x1,y1), (x2,y2), (x3,y3), (x4,y4) for a signal that detected with unknown location using knn. Each of these points have a specific RSSI reading.(rss1, rss2, rss3). How do i apply Bi-linear interpolation to find the x y coordinates of the grid ?

  • Sohel S Shaikh added an answer in Bioplastics:
    Can anyone help me in getting simple extraction method for Bioplastic (PHB/PHA) produced from the Bacteria?

    I have started working  on Bioplastic production in economical way, bioplastics produced usually are intracellular nature, it is time consuming that everytime need to centrifuge, so are there any alternate and simple methods to extract the bioplastic in economical way 

    Sohel S Shaikh · P S G V P Mandals ASC College, shahada

    Is this helpful for you?

  • John P. Garrett added an answer in TESOL:
    ESL / TESOL (SLA) ~ "Reflective Teaching:" Suggested Texts?

    Dear Teachers of English as a Second Language:

         I am compiling an annotated bibliography of 25 texts in the above subject area (ideally for Adult ELL's @ Advanced Intermediate level).

    Any suggested textbooks / resources / references in the above subject area?

    Thank you,

        - JP Garrett  

    TESOL Certificate Practicum

    CLC - Illinois 

    garrettjohn100@gmail.com (Pref. Email)

    jpgarrett@stu.clcillinois.edu (Alt. Email)

    John P. Garrett · College of Lake County

    Thank you Dr. Laura, very impressive & muy simpatico !

    Per my syllabus, the annotated bibliographies must be on "textbooks." [only]

    Any further suggestions on texts? & thanks for your response.

    VTY,

      - JPG 

  • David Cheng added an answer in Dopamine Receptor:
    What is the most efficient method for isolating cytosolic and membrane protein from mouse brain?

    I am planing to measure dopamine receptors in specific brain regions, to study the effect of different form of stress on internalization and postendocyctic fate of dopamine receptors. In this regard what subcellular fraction you would preferred?Eg : cystosolic and membrane fraction or presynaptic and postsynaptic density.

    David Cheng · University of California, Irvine

    Hi Heidi,

    Question regarding the LN2 method.  What is the benefit of doing it this way as opposed to using a homogenizer (if any)?

    Thanks!

  • Sohel S Shaikh added an answer in PHA:
    What is the % sulphuric acid to use for methanolysis of PHA?

    After production of PHA when the monomer content is not known , how to analyse the purity or compound structure by doing GC-MS or HPLC; During methanolysis as shown in the paper should different concentrations of sulphuric acid be used or is it fine to use a fixed concentration of sulphuric acid and it has been discussed that alkaline methanolysis yields a high purity MHB for GC analysis. Looking ahead for a solution in this regard.

    Sohel S Shaikh · P S G V P Mandals ASC College, shahada

    one thing i want to mention here is samplr preparation is very important for PHB GC analysis, if sample not prepared well all PHB Will be evaporated during heating stage. So keep in mind that use every time new tubes with its cork/lead.

  • Habib Gholipour added an answer in Nano Metal Oxides:
    How do I handle nano metal oxides in catalytic oxidation of benzyl alcohol?

    I want methods or papers concerning nano metal oxides in catalytic oxidation of benzyl alcohol

    Habib Gholipour · University of Tehran

    In the photocatalytic oxidation of organic compounds several factors can have considerable effect. Specially inhibitors can hinder photocatalytic degradation of organic  compounds.You can find valuable information in the atached paper. 

  • Jonas Mellin added an answer in Computer Science:
    Which are good books on research methodology for computer science students?

    Most of the researchers following the book written by Prof. Kothari, in India, we need  the book related to research in computer science...

    Jonas Mellin · University of Skövde

    One of my personal favorites: http://www.springer.com/us/book/9783642290435. Note that it is emphasizing software engineering and its strong point is quantitative methods, in particular, experimentation. 

    Concerning performance experiments, the following article is a good example:

    Georges, A, Buytaert, D & Eeckhout, L 2007, ‘Statistically rigorous java performance evaluation’, ACM SIGPLAN Notices, vol. 42, no. 10, p. 57.

  • Vladimir Dananic added an answer in Heat:
    How can I make my nonconvex optimization problem converge to a unique global solution?

    I am trying to update a thermal finite element model with experimental thermography data. I use a gradient based nonlinear least square optimization algorithm using the trust-region reflective algorithm.

    The objective function of my results is simplified explained the difference between the experimental measured temperature and the numerical calculated temperature. The optimized parameters are the experimental parameters as the heat pulse length and the orientation of the heat sources.

    Out of my results I found out that if I optimize more than 4 different parameters, the results converge to non-unique solutions which are dependent of the initial parameter values.

    I already checked the independancy of the parameters and received covariance values of less than 0.4 between the parameters.

    I also checked the routine using a CMA evolution strategy based on the methodology of Hansen which delivers the same problem.

    The tolerance of the optimization routine is set on 10-12.

    Does anybody has an idea what the problem could be?

    Thank you very much for your input.

    Vladimir Dananic · University of Zagreb

    As far as I know this problem is not solved, i.e. there is no algorithm which guarantees to find unique global solution (provided that the global solution is unique indeed).  You may try non-gradient based algorithm, such as so called "amoeba algorithm". By controling the "stretching parameter" there is a hope that the barycentric coordinates would be always large enough to avoid all local minima and settle down on the global minimum. Once found, the global minimum can be refined by gradient based algorithm.

  • Nagarjun Kasaraneni asked a question in Imidazoles:
    Any suggestions for carrying out dialysis and concentration of sorted virions?

    I am working with engineered pseudotyped virions, we have sorted them through Ni-NTA column with 500mM imidazole, I want to concentrate and dialysis them at the same time, any suggestions about the best methods that can be used to carry out both operations at same time and less time period to reduce imidazole concentration. I am not interested in buffer exchange using column as it will reduce the virion titre.    

  • Caitlin Mader asked a question in Trees:
    Can anyone advise on rearing European elm scale (Eriococcus spurius) or similar scale insects, particularly though the winter?

    I am trying to establish a colony of European elm scale, on which I hope to then rear parasitoids of the genus Coccophagus. I am looking at using saplings of American elms, but the winter dormancy required by elms will halt my research through the winter. Does anyone have tips, either to successfully establish these kinds of scales on greenhouse elm trees, or to substitute the trees with another plant species or media that might allow the scales to continue growth and reproduction though the winter months?

  • Sudev Naduvath added an answer in Questionnaire:
    Can you help with as a research participant please?

    Please I need participants to help facilitate my project. The link below would take you to a questionnaire study, please spare few minutes to answer the questions the best you could. Thank you.

    Sudev Naduvath · Vidya Academy of Science & Technology

    Definitely. I will do it today when I get free time.

  • Şakir Bor added an answer in Iron:
    How can I nitride an iron foil?

    I want to form iron nitride phases in a iron foil of 300-450 um(micrometer). It's almost impossible to get the nitriding profile so deep by gas nitridng or by plasma nitriding. However, we don't have access to ammonia gas due to safetyor plasma nitriding process. Now, can anyone here, suggest me any process to nitride my iron foil?

    Şakir Bor · Middle East Technical University

    If you have any nitrided iron part around, on it there may be some White layer, Fe3N4, which is very brittle and can be easily powderized. You may try to couple your foil with the powder and heat around 550C for couple of hours. If the White layer on the part has been removed previously, you can use the nitrided case as well to couple with your foil (form a diffusion couple). Iron cannot be nitrided in nitrogen N2 gas below few thousand atm pressure.

    Please,  under no circustances,,intend to use highly poisonous liguid cynide (CN for nitriding). It may be deadly.

    Hope it helps.

  • Habib Gholipour added an answer in Activated Carbon:
    What is a good electrolyte for KOH activated carbons in 3 electrode system?

    Which electrolyte functions well when we use KOH activated carbons in a 3 electrode system?Using Ag-Agcl as refernce and Pt wire as counter ?Working electrode will be Activated carbon coated over Ni foam?

    Habib Gholipour · University of Tehran

    KOH is better if you don`t use Ni foam. Because Ni foam forms Ni(OH)2 in KOH and you will have substantial error because of red-ox reeactions of Ni(OH)2. I suggest you coat activated carbone on stain less steel grid which is cheap, flexible, and does not contribute in red-ox reactions. If using stain less steel is not possible for you try  KCl or K2SO4 3M aqueous solution.

  • Karuppusamy Arunachalam asked a question in Med:
    Anybody have this article?

    Planta Med. 1981 Dec;43(4):396-403.Pharmacological investigations on vitexin. Prabhakar MC, Bano H, Kumar I, Shamsi MA, Khan MS.

  • Stam Nicolis added an answer in Electrostatics:
    Could the fundamental dimension of Electric Charge be Mass only?

        After solving dimensions of electrical equations, I found out that the fundamental dimension of Electric charge is mass only. This also leads to the derivation of dimensions of other Electrical units like Electric Current, Magnetic flux density etc in terms of Mass, Length and Time only. These are not cgs units.
         This discovery can help unify the force of gravitation that uses mass and the electrostatic force(Force between charges).This will help contribute to the theory of everything, also in better understanding of the electrical units and equations. e.g Work done=Charge times Voltage. Substituting the right handside with their dimensions of Charge=Mass and Voltage=L^2T^-2 proves that the equation is dimensionally consistent. Also other theories can be uncovered and better understood with this finding.
         I wish to be challenged if possible and I will show the steps of the derivation.

    Stam Nicolis · University of Tours

    Instead of using words, that are ambiguous, it's useful to do calculations, where trivial  mistakes are clearly seen. By drawing the appropriate spacetime diagrams and/or using the Lorentz transformations, it's possible to see which statements make sense and which don't. However a discussion forum isn't the appropriate place for correcting undergraduate homework. All these questions, that have been repeatedly asked, are treated with the tools provided  in undergraduate texts on special relativity. These are all misconceptions that stem from the fact that people preferred writing long texts of meaningless words, rather than learning to use the mathematical tools. Once the latter were understood, these issues were resolved. There's no point in repeating mistakes. Incidentally these issues are totally irrelevant to the subject of the discussion, that only makes sense for people that have mastered the background, not for those that try avoiding doing so. The background material can be studied, for instance, in Feynman's lectures, whose link has been provided and exercises are available in many on-line courses, e.g. http://isites.harvard.edu/icb/icb.do?keyword=k97310

  • Kamuran Turksoy asked a question in Blood Volume:
    What is the volume amount used in plasma insulin concentration units in patients with type 1 diabetes?

    Can anyone tell me what volume is used in the units of plasma insulin concentration? The units are usually are mU/L or pmol/L. Is the blood volume used? If so, the blood volume is considered to be approximately 5L which makes the amount of whole plasma insulin 5X mU or 5X pmol. According to clinical plasma insulin measurements the X is not a value larger than 300-500. Is the whole plasma insulin amount really this much low?

  • Tanmay Dichwalkar asked a question in DNA Fragmentation:
    How to quantify DNA fragmentation with imageJ?

    How to quantify DNA fragments in agarose gel electrophoresis with imageJ or any other software?

  • Asier Lacasta added an answer in GPU:
    Is there any tool like PAPI to collect GPU's performance counters?

    Hello all,

    I intend to collect a few events from OpenCL programs like cache-misses, instructions and cycles. As you know, there are tools such as PAPI providing some facilities to read performance counters where and when you want. I wonder if any tool has ever been introduced to do this for OpenCL kernels?

    Regards,

    Asier Lacasta · University of Zaragoza

    I have never used it before so i can't help you with it. Maybe people around here can provide us more information. 

    Regards

  • Xiangmin Sun added an answer in Evaporation Rate:
    What methods are available to model the stable isotope composition of water vapors evaporating from soil under NON-STEADY STATE?

    Bare soil evaporation. How do I model the isotope composition of the resulting vapor or the residual liquid water in the soil, and under non-steady state conditions (i.e. not a constant evaporation rate as modeled by the early works of Barnes and Allison in the 1980s).

    Xiangmin Sun · Texas A&M University

    I guess one is direct measurement via a soil chamber, and another one is Craig-Gordon model.