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  • Why internal dosimetry in nuclear medicine is not taken as seriously by doctors as in radiotherapy?
    Prof. Dr. Ljungber, Dr. Stabin, Dr. Flux, Dr. Celler, Dr. Simpkin, Dr. Zazonico, Dr. Sgouros, Dr. Cremonesi, and many others Authors published a lot of papers, softwares, etc. Even so, very few centers apply internal dosimetry for nuclear medicine therapy. Why?
    Carl A Wesolowski · University of Saskatchewan

    Situations in which radiation exposures are calculated are relatively rare as this has very different rules than external beam radiotherapy. For example, a typical hyperthyroid I-131 therapy dose will deliver a huge radiation dose to the thyroid. We actually do not calculate this when we treat; there is no need to do so as this is unlike external beam radiotherapy and are no side effects as the other body organs do not take up radioiodine at anywhere near the thyroid dose exposure as the thyroid exposure is from the 2000 times higher iodine uptake than plasma concentration (iodine pump).

    There are limited situations for therapy in which dose calculations are needed. These are principally for therapy situations, many when I-131 is given, in which renal failure is an issue, or pulmonary exposure from iodine avid pulmonary metastatic disease is an issue. In the latter case, one wishes to avoid pulmonary fibrosis, and limit the dose to less than 80 rads, which works out to about 30 mCi with normal renal function. For normal renal function, the exposures tend to be multiples of that listed on the suppliers package insert of the type, one mCi equals such and such exposure in the various listed body organs. The critical organ is typically listed (e.g., colon or bladder for I-131 given by mouth), and marrow exposure would be an issue for I-131 therapy in renal failure patients. There are situations in which the spleen is the critical organ, e.g., for In-111 chloride or labeled neutrophils. That would be an issue under the rare circumstance that the patient has splenomegaly from extramedullary hematopoiesis in the course of CML. In that case, even a diagnostic dose of In-111 could cause the spleen to shrink considerably, and substantially reduce hematopoiesis.

    Finally, the vast majority of things done in nuclear medicine are diagnostic, not therapeutic, and the radiation exposure is typically worth the risk of 2 miles driven on a highway. Since some of our patients make 200 mile round trips to see us for their tests, we usually don't talk about the radiation exposure.

  • Marc Verhaegen added an answer in Fossils:
    Why Australopithecine type hominids are missing in South Asian fossil record?

    Because environment was becoming colder and ecology turning to grasslands unfavorable for the later hominoids and hominids

    Marc Verhaegen · Study Center Anthropology

    Anek-  Why gorillas evolved rel.thin enamel is uncertain. Enamel thickness appears & disappears frequently in evolution. Gorilla's thin enamel (sharper ridges, e.g. to slice herbs) seems to be an adaptation to more terrestrial herbaceous vegetation (THV), whereas their ancestors ate more aquatic herbaceous vegetation (AHV). Chimps (less herbivorous) have intermediate enamel. Humans & orangs kept the thick enamel (more omni- or (hard?)frugivory). Wetland hominoids seem to have had (super)thick enamel (e.g. poor quality of sedges etc.? small snails on AHV?), but the Pleistocene coolings & dryings apparently favored a more terrestrial life cf parallel evolution of knuckle-walking in Pan // Gorilla. Most monkeys (herbivorous) have rel.thin enamel, but e.g. the omnivorous capuchins have rel.thick enamel (hard-object-feeding? nuts? hard-shelled invertebrates? mangrove oysters?). In many instances (e.g. enamel thickness), Pan & Gorilla are apparently more derived (e.g. drier forests? ground-dwelling?) than Pongo or Homo.

  • Philip C Adams added an answer in Cardiology:
    What is your first choice of anti-platelet drugs in patients using warfarin and submitted to stent implantation?

    I use always clopidogrel in these patients.

    Philip C Adams · The Newcastle upon Tyne Hospitals NHS Foundation Trust

    How those new data impact on the decisions I must admit I am challenged to understand. Such a different approach to WOEST. Interesting they kept the aspirin - which I suspect is unnecessary if you are on a thienopyridine. Thanks very much for bringing this to our attention.

  • Yuezhong Wen added an answer in Graphene:
    How to quantify graphene in vivo with a simple, facile method?
    Since the discovery of graphene, graphene has been extensively explored in application in vivo. But its quantitative analysis is not easy, it is difficult to know where it goes and how to change? Maybe isotopic labelling is a good method, but it is not simple and facile. Can you give me some suggestions about this problem? Thank you.
    Yuezhong Wen · Zhejiang University

    Maybe isotopic labelling is a good method, but it is not simple and facile

  • Xiang-Bin Wang added an answer in Electroporation:
    Why am I getting low MAb expression in DG44 CHO cells?


    I am attempting to express a mAb in DG44 cells. I am using pcdna3.1 with the ovalbumin signal peptide and using the amaxa electroporator for transfection (5 ml cells with 1ug/ml dna). I am seeing very low expression (20 ng/ml) via ELISA. I have tested for efficiency with eGFP plasmid and it seems fine.

    What is the most obvious thing I am doing wrong or is this low expression simply normal in dg44? Would it be possible it if is abnormal to compare this to a control vector for mAb expression in DG44?

    Xiang-Bin Wang · HIAT: Hongye Innovative antibody technology Co., Ltd., Beijing, China

    I you want to express mAb by transient expression, you can use pCDNA3.1 together with 293T or 293FT cells. CHO-DG44 is not a optimal host for this plasmid.

    Also, you antibody sequence or the leader should be optimized to improve the expression level.

    my email is CTO@innovabtech.com. I have a lot of easy to use system in hand and related experience. you can contact me by email if you want.

  • What would be definition of environmental history?
    I know there are many definitions, but I'm interested in different opinions.
    Miguel Aguilar Robledo · Universidad Autónoma de San Luis Potosí

    Thanks David!



  • Therapeutic effects of bee venom

    therapeutic effects of bee venom

  • Problem when Hausman test compares Fix effect ( with lag dependent variable as regressor or Dynamic fix effect model) with Random effect model.
    I have a question and problem in this situation . when I want to compare fixed effect model with lag dependent variable as regressor( or dynamic fix effect) with random effect , then Hausman test uses only fix model not (lag dependent regrssor model) .
    I face difficulty in this situation.
    Furthermore if i want to Plot graph of Fixed effect model then in this situation EViews not provide any help or may i not know that.
    Tarique Hossain · California State Polytechnic University, Pomona

    It appears this topic has been discussed in STATA newsgroups. You might find STATA offering better capability. Here is the link to STATA discussion:


  • Who are the top researchers in Behavioral finance?
    Who are they, what are they researching and what are the universities leading the topics?
    Theodore C. Moorman · Baylor University

    The following two papers are highly cited behavioral finance papers.  In this regard, their authors may be considered top researchers.

    Barberis, N., A. Shleifer, and R. W. Vishny, 1998, “A Model of Investor Sentiments,” Journal of Financial Economics 49, 307-343

    Daniel, Kent, David Hirshleifer, and Avanidhar Subrahmanyam, 1998, “Investor Psychology and Security Market Under- and Overreactions,” Journal of Finance 53, 1839-1885.

  • Peter T Breuer added an answer in Reductionism:
    I am looking for an open source CSP theory code, preferably written in C or C++, does anyone has anything that could help me?

    I am currently performing detailed analysis of some pyrolysis mechanisms. In order to perform model reduction I would like to "be introduced" to CSP. Thanks in advance.

    Peter T Breuer · Birmingham City University

    Then perhaps you might like to say so! Your question needs explaining, at least as far as identifying the intended field of knowledge.

    You might also like to pay attention to the topics keywords. I'm pretty sure you don't mean "reductionism"! Carnap would turn in his grave ...

  • Loopinder Sood added an answer in Genetic Algorithm:
    What is the appropriate behavior of population standard deviation in a genetic algorithm?

    A genetic algorithm for a minimization problem, has number of generations as the termination criteria. I understand that the best solution will be the one with the lowest objective function value. I also see that the objective function values of the solutions will tend to reduce with each successive generation as it approaches the best solution.

    My question is:

    if the raw objective function values are transformed with this fitness function

    Y - x(i) / sum x(i)


    x(i) = individual raw objective function values 

    sum x(i) = sum of all the raw objective function values of the population

    Y = large positive integer

    How will the standard deviation of the fitness functions behave?

    For the problem I am solving, the standard deviation tends to have an inverse relationship with the fitness values ie where the fitness value is an maxima, the standard deviation is a minima. and vice versa is this correct, please is there a source article where I can find details for this.

    Loopinder Sood · Coventry and Warwickshire Partnership NHS Trust

    The SD is related to the genetic diversity of the population, which starts of high initially and reduces as the chromosomes get fitter and fitter and converge to a solution. So as the fitness increases, the genetic diversity decreases, as does the SD.

  • Arun Gandrathi added an answer in Mouse Models:
    How to perform local injections in the CA1 stratum radiatum before in vivo electrophysiological recordings?
    I am doing in vivo electrophysiology in the CA3/CA1 schaffer collateral in C57Bl6. I would like to inject some drugs locally in the CA1 stratum radiatum before proceeding with the recording. I would like to find a method that allows the injection of a drug in the same place where I’m supposed to record. Does anyone know a technique accurate enough for this purpose? I heard about an injection needle glued to a recording electrode but it’s very difficult to make. Any help is much appreciated. If you need more information, I’m available to provide it. Thanks in advance!
    Arun Gandrathi · University of Melbourne

    Hi Jose,

    I have done such experiments before successfully. As Mer-Shahram Safari mentioned in his fourth point, i have used multi barrel pipettes for such experiments. Gluing two electrodes is hard and it form two different tips, using multi barrel glass pipettes with separate filaments is of great advantage. When you pull them it forms a common tip so that you can infuse your drug around the recording site. The method of infusion of drug is also very important. I used micro-iontophoresis technique, it is a bit complicated and also may alter the quality of the recordings. I have published a paper describing such techniques. Please find "An in vivo technique for investigating electrophysiological effects of centrally administered drugs on single neurons and network behaviour". Hope it helps.

  • Robin Spivey added an answer in Theoretical Physics:
    Could time dilation prevent the formation of black holes?
    As we get close in time to the formation of an event horizon, then in the vicinity of the location where that event horizon will form in the future, time dilation becomes very large. The formation of the event horizon must depend on continued entry of material from beyond the radius where the event horizon will form, otherwise it would have already formed. A tiny differential instant before it forms time dilation approaches infinity.

    Of course in the proper time of an observer at that location, there is no time dilation and the black hole forms. But has anyone considered that in the reference frame of a more distant observer in the normal universe there may be no event horizon ever really existing in that observer's reference frame?
    Robin Spivey · Bangor University

    Matts, I have dug out our posts from the other thread to remind you of our exchanges some two weeks ago.

    (I had mentioned that In a 1939 paper Einstein wrote "it is easy to show that both light rays and material particles take an infinitely long coordinate time in order to reach the point r=2m when originating from a point r>2m").

    15 days ago, I wrote:
    Einstein was right about the infinite time dilation and also that the proof is straightforward. What is not so easy to show (not least because it contradicts this) is that a test particle can "easily cross the event horizon". I previously asked if anyone knew of a mathematical example in which this occurs *while the external universe still exists*.

    15 days ago, you replied:
    Robin, You seem to ask for a disproof that a test particle cannot "easily cross the event horizon". Your logic is confusing to me. It occurs in various black hole geometries (Schwarzschild, Kerr, Kerr-Newman etc.), why should anyone have to disprove that it does not occur?

    (after further clarification from me, pointing out the importance of the clause *while the external universe still exists*)

    14 days ago, you wrote
    Robin, you are right that the infalling photon grinds to a halt at the horizon from the perspective of any realistic onlooker (i.e. the external universe). But your conclusion has to be rephrased: Evidently, Schwarzschild black holes cannot be seen by outside observers to capture particles. They still do, but the horizon hinders us from seeing it.

    Here on this thread, some three hours ago, you wrote "Robin I cannot have said that stationary black holes can absorb matter in finite external time". Excuse me, but if you are not being shadowed by some impersonator, I think you effectively did.

  • Eric Uslaner added an answer in Social Capital:
    Is there a used scale for measuring family social capital?

    I want to measure family social capital in firms. 

    Eric Uslaner · University of Maryland, College Park

    Add a little bit of this and a little bit of that and you get a mixture that doesn't mix:


    Social capital is all stuff that is good (so it must include ratings of IPAs)  Most of these things are uncorrelated with each other.You can try to create an index of anything you wish, but take heed of the advice of Warren Torgerson in a 1965 Presidential address to the Psychometric Society (he was one of the inventors of multidimensional scaling): It is often better to know whether something is an animal, a mineral, or a vegetable rather than having a high loading on the animalness factor and a low loading on the bipolar mineralness-vegetableness dimension."  

  • Krzysztof Herman added an answer in Bioacoustics:
    Decibelimeter model for bioacoustic research?

    I am looking for a decibelimeter for bioacoustic research that is not as expensive as a Brüel & Kjær and that has an enough quality. Any tips?

    Krzysztof Herman · Wroclaw University of Technology

    What kind of research would You like do I mean signal bandwidth and dynamics ?

    Maybe I can recomend You something but give please more details.

  • Golam Kibria added an answer in Activated Carbon:
    What is the best way to modified activated carbon


    what is the best way to modified activated carbon. I want to have high surface area and to support metal ? 

    Golam Kibria · RMIT University

    The following review paper may be helpful as it provide a comprehensive list of literatures on chemical, physical and biological modification techniques of activated carbon (AC) pertaining to enhancement of contaminant removal from aqueous solutions was compiled and reviewed.  Types of microorganism adsorbed on AC and chemical species removed include copper, zinc, nickel, lead, cadmium


    Chun Yang Yin, Mohd Kheireddine Aroua, Wan Mohd Ashri Wan Daud. 2007.Review of modifications of activated carbon for enhancing contaminant uptakes from aqueous solutions. Separation and Purification Technology 52: 403–415. http://www.sciencedirect.com/science/article/pii/S1383586606002024

  • Zahra Wg added an answer in Cyclic Voltammetry:
    How can I determine the Peak Current in Cyclic Voltammetry?

    Dear all,

    I have done CV tests on my samples. It seems that the voltammogram is featureless. It doesn't look like voltammograms which is described in text books. So I don't know how to determine peak current and what kind of information is possible for me to extract. 

    How can I determine cathodic peak current and also anodic one if there is? How can I determine baseline of this voltammogram? 


    Zahra Wg · Materials and Energy Research Center

    Dear Mr Ahmed Bahloul , 

    Thank you for your great comment, but about first one or anodic peak, I don't need to mention baseline?! It doesn't seem to be correct. I really have problem with this matter!

  • Tarique Hossain added an answer in Dairy:
    Does anyone know how much the price of per unit milk production? how can calcutet this by simple equation?

    i working at the cuttle farm and use same initial  requirement for prudence.I want to calculate ultimate price of production.I need to best an simple formula of pric product.   

    Tarique Hossain · California State Polytechnic University, Pomona

    Dear Khayyam,

    There may be some rule of thumbs out there, but the cattle farming structure can vary so much from one farm to another that one "catch all" model (or equation, as you put it) would be difficult to build if you want reasonable accuracy. For example, the fixed costs can vary if the farm/land is owned versus rented. Besides, there will be many assumptions to be made, such as the average age of the cattle and the life cycle of their milk production, their breed, growth hormones, if any, and so on. You can try building a simple model in a spreadsheet, trying to include all the variables of interest.

    Another option is econometrically estimating an equation, say, using a regression model using secondary data on milk price and other explanatory factors such as feed price, cost of maintaining dairy cattle, and anything of that nature (as much as data availability permits). Then use the coefficients to predict milk price if one of the predictor variables (e.g. feed price) changes.

    I have a feeling you are trying to do the latter, i.e., the econometric method. Then get busy collecting data and try to fit models using any easily available software. Excel can handle OLS regressions if you have the analysis pack installed.

    Hope this helps. Good luck.


  • Denis Pinha asked a question in Health Care Systems:
    What are the main constraints for managing multiple projects in health care systems?

    In order to develop a model to deal with project scheduling in health care system, I would like to know what have been used as common resource constraints in the literature?

  • Jun-Long Kou added an answer in Comsol Multiphysics:
    How can I export graphics from COMSOL 4.3 with good resolution?
    I am exporting or saving the graphics but the getting a faded image. What can I do now? I need the images (streamlines and isotherms) with good resolution.
    Jun-Long Kou · California Institute of Technology

    I recommend exporting the data and plot using matlab. That would gives you more freedom.

  • Mohamed Abd El-Aal added an answer in Rumex:
    Can anyone help in identifying of this plant?

    This plant was collected from orchards, about 180 cm in height, i think it is one type of Rumex

    Mohamed Abd El-Aal · Mansoura University

    thanks too much

  • Has anyone ever noticed hippocampal neuron death after the addition of Ara-C?

    I added Ara-C on Saturday (3 DIV), and while I thought it was the right choice at the time, I also have my cells plated in serum free medium and not in co-culture with astrocytes. I am afraid the addition of too much Ara-C (5uM) may have been toxic to the neurons? At this stage, should I partially replace or dilute the medium to prevent the healthy ones from succumbing to death? I also plated the cells at low density (40,000/18mm coverslip). They are supplemented with B-27, but could this be an issue?

    Trisha Stankiewicz · Stanford University

    Thank you everyone for your suggestions!

  • How could I apply a uniform magnetic field perpendicular to photonic crystal fiber by using COMSL?

    I need To apply a uniform magnetic field in perpendicular direction on photonic crystal fiber by using COMSOL multiphysics or any other software, I am already design a PCF with COMSOL.


    Jun-Long Kou · California Institute of Technology

    Use magnetic field boundary condition. Surface current maybe helps too.

  • Michael Lubwama added an answer in Reductionism:
    How can I avoid the deposition of silver on the walls of reaction vessel?

    Can anybody help me to solve the issue of depositing silver nanoparticles on the walls of the reaction vessel instead of the target templates during reduction of silver nitrate? How can i avoid this and ensure that the silver nanoparticles are getting attached only on the substrate particles?

    Michael Lubwama · Makerere University

    The exact experimental set up is necessary for a correct answer to be given. It could be an issue with the bias voltage or even the way you are using mechanical shutters if it's a magnetron sputtering system. Or it could be a number of issues really

  • Daniel Lerda added an answer in Mycotoxins:
    When we optimize the detection conditions of an instrument for mycotoxins, should we use the analytical standards of mycotoxins or spiked sample?

    I am working on a optimization study of LC-MS/MS detection conditions (flow rate, mobile phase composition...) for simultaneous determination of some mycotoxins. I found that some researchers used analytical standards of mycotoxins optimize the condition wile the others used spiked samples. which one is adviseable? for my understanding the advantage and disadvantages of the two are,

    1.Standard: the chromatographic response (eg, peak area) is just resulted from  the instrument condition. But some people said it will be not so efficient without a sample matrix.

    Spiked sample: in this case the chromatographic response (eg, peak area) is resulted from not only the instrument condition but also the sample extraction efficiency right?then the there will be more error, cause some difficulty on determining the exact optimum instrument condition.

    Daniel Lerda · Catholic University of Córdoba

     I agree with Anca-Maria Tugulea. Both are necessary to develop and validate a protocol.

  • Does anyone know any remedial measures to take for repeat breeding (unable to conceive even after 3 successive services) dairy cattle in farms?
    Other than frequent culling. something like any treatments proven by research.
    Rafael Maria Roman · University of Zulia

    The esasy one!!! ... sent those cows to the slaughterhouse

  • Is there any software to calculate the enantiomeric or diastereomeric excess in organic molecules?
    As we have been involved in docking, SAR, QSAR and DFT calculation using Schrödinger software, I started thinking about possibility of using any software for theoretical calculation of stereoselectivity in organic molecules. It can be helpful to organic chemists to check the probabilities/optimization of conditions for the formation "ee" and "de" in product before doing experiments. If you have any idea, please comment on this.
    Jacek Martynow · Melinta Therapeutics

    Imre - exactly! Reaction kinetics is everything in majority of asymmetric syntheses. It is a function not only of the reactant structures, but multiple other factors come into play, like the effects of concentration, pH, temperature, pressure, complex catalytic interactions with trace components, etc. A practicing chemist might just not feel that such calculations have practical value... until proven convincingly, of course :)

  • Adam B Shapiro added an answer in Disulfides:
    How to use Ellman's reagent (DTNB) for determination of Tm of disulfide?

    I have a beta barrel protein with a single interior disulfide.  I would like to use Ellman's reagent (DTNB) to determine at what temperature the disulfide breaks via the absorbance of TNB at 412 nm.  Since I know the protein doesn't start unfolding until close to 50° C, I would expect relatively little change in absorbance at 412 nm until that temperature, then a significant increase when the disulfide breaks followed by little change in absorbance following complete denaturation of the disulfide, resulting in a sigmoidal curve of absorbance at 412 nm versus temperature.  However, I get something that looks more like an exponential curve.  What could be causing this?

    Adam B Shapiro · AstraZeneca

    Firstly, I don't think the disulfide bond will break as a result of protein unfolding in the absence of a reductant. Secondly, since Ellman's reagent is not a very sensitive method, you must have a pretty high protein concentration in your experiment, probably several micromolar at least. If this much protein is aggregating/precipitating as it is heated, this will cause the absorbance to increase due to light scattering. To test for this, just leave out the Ellman's reagent and see if you get the same effect.

  • How can I calculate exhaust gas flow in an IC engine?
    I need to calculate the exhaust gas flow theoretically.
    Hasan Kayhan Kayadelen · Yildiz Technical University

    You may simulate the engine combustion by using a chemical equilibrium code which will give the mole fractions and also mole numbers of the species i.e exhaust gas composition. 

  • Christa Walther added an answer in FACS:
    Is it possible to regulate FACS FL1 signal distances?
    I'm doing a FACS experiment to see the ROS changes with DCF-DA.

    Usually control signal is got by DCF-DA untreated cells and the signal which I am interested in is got by DCF-DA treated cells.

    In my case, I'm interested in WT cell type and KO cell.
    Therefore I can't control the cell dependent DCF-DA signal intensities.
    DCF-DA untreated cell signal comes from FL1 power about 750.
    However DCF-DA treated cell signal comes from FL1 power about 250.

    What I want to is represent two signals at the same graph.
    Briefly, the distance between DCF-DA untreated and treated signal can be
    controlled by FACS parameters?

    DCF-DA Untreated signal (U) : represent as 10 at 750 FL1 power.
    DCF-DA Treated signal (T) : represent as 100 at 250 FL1 power.

    Our FACS machine has a detection range from 10 to 10,000.
    Even if I controlled FL1 power up and down,
    I can't place both U and T signals at the same graph range.

    Is there any solution for this problem except using a more advanced machine
    which has a detection range up to 100,000?
    Christa Walther · The University of Sheffield

    If your FL1 signal is to bright you might be able to detect in FL2 and use this channel to show both results in one histogram. Make sure you place your controls/ untreated samples in FL2 properly as well as described above. You should keep the 'power' constant while comparing treated and untreated cells and if possible between different cell types you want to compare. If the FL2 channel does not work for both samples or you need to change the amplification between samples due to a large difference in autofluorescence in the untreated sample you could try calculating the delta between treated and untreated samples (the shift in fluorescence intensity) and compare those.