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  • Bachir Achour added an answer in Water Analysis:
    Can ground water have dissolved oxygen? if yes what is its potable limit?

    Drinking water quality, water analysis

    Bachir Achour · Biskra University, Algeria

    Dear Singh,

    Logically, there is no oxygen in the groundwater because there is no interface with the atmosphere. There may be the CO2 which comes from the cabone cycle. The oxygen could come from the photosynthesis if the water contains algae. But this is unlikely.

    With my best regards

    Prof. Bachir ACHOUR

  • Divaker Choubey added an answer in Cell Adhesion:
    How can I detach generated BMDC from petri dish?

    I use the lutz 1999 protocol with minor differences, but when I have to detach the cells on day 8-9, I have serious issues. The cells are strongly adhered to the petri dish. I have used cold PBS 2mM EDTA with poor results, so I tried increasing to 5mM EDTA. I waited for over 20 minutes at RT and after a lot of pippeting recover over 90% cells with 80-90% viability. I noticed everybody says they just recover by pippeting with cold PBS, so please If someone can help me cause then I have to activate them for another 16hrs and I have the same problem trying to recover them. :)

    Divaker Choubey · University of Cincinnati

    We use TrypLE from Invitrogen at 37 degree C. This solution gently releases cells and cells recover fast after release from plates. However, some optimization may be needed for cell culture plates that you are using.

  • Seshank Mutya asked a question in GPU:
    Is there a way to decrease gpu/cpu ratio of performance in GROMACS?

    when ever i run a simulation in gromacs i end having a note saying GPU is 20% more in use than cpu which could decrease the performance and GPU/CPU ratio is 7.5 which should be ideally. Suggest me a way out to improve my performance.

  • Nazreen Chowdhury asked a question in Pursuing PHD:
    Can anyone suggest what is the new topic on behavioral finance to pursue phd ?

    I am planning to write a phd proposal on behavioral finance . After going through almost 20 articles I found that most of the researchers were focusing on factors affecting investors decisions. I also wanted to write a proposal similar to that but now I need some suggestions to write something new on that topic. Any suggestions please ?

  • Huong Ha added an answer in Primary Cell Culture:
    Does anyone know an inhibitor for non-neuronal cells in cell culture? (apart from araC)
    I want to culture primary cortical neurons from mice, but after 12DIV, they start to die (PLL coating and media are optimized). I've read that after 5d, non-neuronal cells like glial cells start to proliferate and by inhibiting their proliferation it is possible to yield a "neuron-only" culture. I was reading through the literature but found only araC as efficient inhibitor. Are there any alternatives? If yes, at which concentration would you use it?
    Huong Ha · Stanford University

    Hi all,

    I am also having a similar problem with our rat embryonic hippocampal culture. We are using Neurobasal/B27 which by itself does not promote a whole lot of glia growth. However, we have an astrocyte feeder layer to keep the neurons healthy and develop reliably (banker style). And these astrocytes seem to promote the proliferation of oligodendrocyte progenitor cells since DIV 7 and on ward. I am thinking of using either AraC or FUDR to fix this problem. Do you have a suggestion for which concentration, when to apply and how long to apply either of these drugs? Do you prefer one above the other? I am using these neurons for electrophysiology, so they need to be active and happy for at least 2 - 3 weeks. If you have other thoughts or tips, please also let me know!!!  Thanks a lot! 

  • Louis Brassard added an answer in Spinoza:
    Descartes admits a real plurality of single substance which have in 'thought' their essential attributes. From what this plurality comes from?

    Descartes intends for ‘attribute’ the fundamental characteristics of the infinite substances. The only ones that we can actually get to know are: thinking and extension (res cogitans and res extensa). Material things derive from the attribute of extension and all non material things by the attribute of thought, or rather - as Spinoza says - things and ideas are respectively the ways of being of the attribute: extension and the ways of being of the attribute: thought.

    In the text of the philosopher Vladimir Solov’ëv 'The Crisis of Western Philosophy' as a deepening of the thought of Descartes we have his admission of a real plurality of things or individual substances that have in ‘thought’ and in ‘extension’ their essential attributes; Descartes recognizes the authentic existence of a plurality of bodies and a plurality of spirits. But from what does this plurality come from? What is the difference of the various substances between them?

    As for Descartes, all the content of an extended substance condenses in the extension, an extended substance can be distinguished from another only because of particular forms or modes. In fact, a material object stands out and is separated from another by a) its position in space, b) its size, c) its configuration, and d) for the coordination of its parts. Now, all this is nothing more than a series of particular ways of extension and has absolutely nothing to do with the substance itself as such.

    The same must be said about the relationships that are established between two thinking substances, because the thought and its particular forms are to the thinking substance as the extension and its particular forms are to the extended substance. But, in this way, if all that determines the difference and the separation is condensed in the attributes and in their ways and has nothing to do with the substances themselves, and if the substances themselves, as substances, do not differ at all from each other but are absolutely identical, it is evident that several substances do not exist, and there is, instead, only one that has as its attributes and at the same title, both thought and extension.

    But to what are reduced in this case the things and the single individual beings? In their uniqueness they can not be substances because the substance is only one; they may not even be its attributes because the attribute, by definition, is the common content of all things of the same nature. It only remains to consider individual things as particular ways of the attributes: a single material object will be a way of extension, a thinking individual, a spirit, will be a way of thought.

    The Encyclopedia Sapere.it shows that in its broadest logical- grammarian meaning, attribute is each determination of a subject that is affirmed or denied. In this sense the term attribute coincides with the term ‘predicate’, the significance of which is now used almost exclusively. Strictly, attribute is opposed to accident and to the way, as a quality inherent and constitutive of substance.

    In this sense the term is used by Descartes who intends for attributes the permanent qualities of the substance, finite. Is then used by Spinoza for whom - since there are no finite substances - the attributes are of God alone, the only infinite substance, and, infinite in the number, they shall express the eternal essence. However, of these infinite attributes of substance we can know only two: thought and extension. The term is involved in the discussions of English empiricism, which, through the analyses of Locke, Berkeley and Hume, leads to the denial of the reality of substance.

    The English empiricism, first with John Locke and then more decisively with David Hume, reacts to the conception of the subject as substance, criticizing both his notion (Locke), then the same "subject" (Hume). But thus empiricism comes to skepticism, to the inability to place the correlation between subject and predicate on solid foundations having an impact on the possibility of scientific knowledge. Like Descartes, although starting from an opposite perspective, the empiricists come to a dualism, to a split between the subjective dimension of experience, and the objective one of external reality. This gap between reality and its subjective representations coming from experience will be radicalized by Kant as an opposition between phenomenon and ‘thing’ in itself.

    In contrast to the old one, now it is the subject to prevail on the external object, until becoming a metaphysical independent entity (Descartes), generating as a reaction the denial of the substance (empiricism).

    Louis Brassard ·

    Dear Gianrocco,

    Beautifull story.  Here a old persian story about truth

    A Persian Fable
    There is an old fable which tells that Truth and Falsehood went for
    A swim together, leaving their clothes on shore. Falsehood
    Coming out of the water first, puts on Truth’s clothes.
    Truth, being what it is, absolutely refused to wear
    Falsehood’s clothes, thus remained naked.
    Ever since then, Falsehood appearing
    As Truth, has been accepted as
    Truth, while Truth still
    Awaits to be seen.

  • Enping Hong added an answer in HEPES:
    Does anyone have any recommendations for growing 3T3s to confluence?

    I have just started using NIH-3T3 fibroblasts for my experiments, but I am having some issues with growing these cells. I am currently seeding them in 12-well plates at 50K cells per well, but I am noticing a couple of issues. (1) I see lots of cells floating in the media and not adhering. (2) A group of cells settle in the middle of the well and reach confluence, but do not seem to spread out much beyond the center of the well. I estimate that this bunch of cells only covers about 10-20% of the total well volume.

    Does anyone have any recommendations or best practices for growing 3T3s to confluence? I am keen on harvesting conditioned media from these cells, so the more cells the better. The media I am currently using is DMEM supplemented with 10% FBS, penicillin/streptomycin, HEPES buffer, and beta-mercaptoethanol.

    Thank you!

    Enping Hong · Yale University

    Thanks Daniel, I'll try that right away! Much appreciated. It's a little confusing when a number of papers I've seen cite their media supplement as FBS or FCS!

  • Taha Akram asked a question in Tunneling:
    Is there any other software except Oasys XDisp by which I can do tunnel analysis based on semi-empirical methods?

    I am currently working on my research on tunnel analysis based on semi-empirical models. So far I have only come across Oasys XDisp but I am looking to an option of any other package which works on the same principles.

  • Graeme Smith added an answer in Cognitive Systems:
    Is Chalmers' so-called "hard problem" in consciousness real?

    In his 2014 book "Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts" Stanislas Dehaene wrote "Chalmers, a philosopher of the University of Arizona, is famous for introducing a distinction between the easy and the hard problems. The easy problem of consciousness, he argues, consists in explaining the many functions of the brain: how do we recognize a face, a word, or a landscape? How do we extract information form the senses and use it to guide our behavior? How do we generate sentences to describe what we feel?

    “Although all these questions are associated with consciousness,” Chalmers argues, “they all concern the objective mechanisms of the cognitive system, and consequently, we have every reason to expect that continued work in cognitive psychology and neuroscience will answer them. By contrast the hard problem is the “question of how physical processes in the brain give rise to subjective experience … the way things feel for the subject. When we see for example, we experience visual sensations, such as that of vivid blue. Or think of the ineffable sound of a distant oboe, the agony of an intense pain, the sparkle of happiness or the meditative quality of a moment lost in thought … It is these phenomena that poses the real mystery of the mind”."

    Stanislas Dehaene's opinion is "that Chalmers swapped the labels: it is the “easy” problem that is hard, while the “hard” problem just seems hard because it engages ill-defined intuitions. Once our intuition is educated by cognitive neuroscience and computer simulations, Chalmers’ “hard problem” will evaporate".

    Personally, I agree with Stanislas Dehaene's opinion.

    Graeme Smith ·

    Ravinder, I can't agree with you on the best way to understand the workings of the brain, I believe there are too many illusions to be found in meditation. Better to build up from neurons and learn what the system does, than fall for an illusion caused by some automatic assumption that the brain makes.

  • Qasim Mohammed Hussein asked a question in Children:
    How does the parents of children act toward their children that are refused to go to school?

    With the beginning of the school year, parents are suffering from rejection of their youngsters to go to school.
    What is the ideal act that followed by parents to get their children to go to school?

  • Huong Ha added an answer in Primary Neuronal Cultures:
    Any suggestions on Ara-C addition in primary neuronal cultures?

    Hi all

    I am culturing hippocampal neurons and on the 7th day after seeding, I add Ara-C at 10 microliters/ml of media. Of late, the ara-C is just not working. There is extensive proliferation of the glia. It's also difficult to prepare ara-c very accurately as the amount by weight required for that is extremely less. Also, I think instead of helping to limit glial proliferation, the ara-C has killed my neurons too.

    Any kind of help in this regard would be deeply appreciated.

    Huong Ha · Stanford University

     Hi Michael,

    I am also having a similar problem with our rat embryonic hippocampal culture. We are using Neurobasal/B27 which by itself does not promote glia growth. However, we have an astrocyte feeder layer to keep the neurons healthy and develop reliably. And these astrocytes seem to promote the proliferation of oligodendrocyte progenitor cells since DIV 7 and on ward. I am thinking of using FUDR to fix this problem. Do you have a suggestion for which concentration and how long to apply the FUDR? 

    Thanks a lot!

  • Christian Baumgarten added an answer in De-Broglie Bohm Theory:
    How do you see the non-locality of the wave-function and why it can't be used for the faster than light signaling?

    The wave-function describes a form of quantum energy called the quantum potential which propagates throughout space. Disturbing the quantum potential in one location instantly modifies it throughout the whole space. How you see this aspect related to the velocity of light?

    Christian Baumgarten · Paul Scherrer Institut


    science is about objectivity, religion about subjectivity. I don't think that it is a good idea to include subjectivity in science and claiming objectivity makes religion intolerant and dangerous. But I admit that science should become aware of its (objective) limitations.

    Synchronicity is an interesting topic. However (if I understand the concept right), it is not compatible with reproducibility. Science is restricted to objective and reproducible events.

    There is other knowledge than scientific knowledge - the type of knowledge that is expressed in fine arts, music and literature. But I dislike the idea to make these things accessible to science - if at all possible.

  • Marxia Oli. Sigo added an answer in Corporate Governance:
    Can any one suggest a variable that moderates the relationship between corporate governance and dividend payout?

    in the light of  a country that is characterized with weak corporate governance, what moderating variable would you suggest to be used in order to moderate the relationship between corporate governance and dividend payout (corporate governance is the IV and dividend payout as the DV).

    Marxia Oli. Sigo · Bharathidasan University

    Hi Adamu Idris Adamu,

    You can refer my article, if you are interested.

    Corporate Governance and the Determinants of Dividend Policies of Information Technology Companies in India

    SSRN Electronic Journal 01/2013; DOI:10.2139/ssrn.2339030

  • Anthony Tam asked a question in ANOVA:
    What test to use when testing effect of drug on mice and compare between male and female?

    I want to test the effect of a drug on male and female C57Bl6 mice, and want to test whether the male or female mice have different responses from the drug.

    Is it more appropriate to use 2-way ANOVA rather than 1-way ANOVA?


  • V. G. Rousseau asked a question in Galileo:
    Is correct to talk about "Newtons' Laws of Motions"?

    First of all, Newton's first law is not from Newton but from Galileo who fully understood what the Law of Inertia was. Newton may have reformulated it in a more mathematical way, but Galileo's statement was correct.

    Newton's second law is really from Newton... However, it is not a LAW but a DEFINITION of a force. In other words, the validity of the so-called "second law" relies only on the validity of the first one (and only one).

    Finally, Newton's third law is not a law either, as it can be derived from the so-called "second law".

  • Harleen Kaur Dhaliwal added an answer in Agar:
    Can you grow Staphylococcus aureus on mannitol salt agar?

    Do all species grow/show phenol red degradation?

    Harleen Kaur Dhaliwal · Institute of Chemical Technology, Mumbai

    Sir, what are the characteristics for specifically identifying these colonies?

  • Piotr Nyczka added an answer in Nepotism:
    Does anyone know how to measure supervisor's preferential treatment over subordinates in workplace?

    I am looking for an instrument that can measure supervisor's preferential treatment in workplace, which can be assessed by the responses obtained from the subordinates. There are several forms of preferential treatment and my focus is mostly on favouritism, nepotism and cronyism. It would be of great help if I could some help. 

    Piotr Nyczka · University of Wroclaw

    I think there is none, or even if there is, it will be misleading for sure. It is highly complex interaction, and im not sure if it could be asessed and collapsed to one number easily.

  • Paul Sevigny added an answer in Applied Linguistics:
    What is the best conference format for a roundtable discussion in applied linguistics or cultural studies? How does it differ from a panel discussion?

    I want to create a roundtable discussion format for a cultural studies conference. I currently have a 150 minute 5-6 person panel discussion standard where there is a general abstract and then individual expert abstracts for their 20 minute presentations with moderated discussion from the audience at the end. I want to create a roundtable alternative to this. What standard roles/rules work best for this?

    Paul Sevigny · Ritsumeikan Asia Pacific University

    Dear Hetta,

    I woke this morning realizing that I need a way to draw participants into the discussion and then just read your response! Creating topic groups and allowing audience members to join any of these groups will be very well-received, depending on the turnout that we get. I think the x factor for roundtable discussion is the number of attendees and how to involve them. Since ours is a small conference, we may be able to just have one large circle and invite guests to join one whole group... With these two alternatives, I think I am armed to finish the planning.... 

  • Damir Zubac added an answer in Protein Analysis:
    Turbidimetric method in the analysis of total protein content ?

    Is someone familiar with the applicability of turbidimetric method in urinary proteins analysis , sampled for a first morning void of the bladder ?

    Damir Zubac · University of Split

     According to ( REF) ?

  • Harleen Kaur Dhaliwal added an answer in Staphylococcus:
    Reliable protocol to isolate efficiently Staphylococcus aureus and S. epidermis from complex samples?
    I'm planning to sample several environments looking for Staphylococci species specifically. Is there any protocol permitting to select them efficiently? For example, which medium is the most selective? What are the biochemical tests which are reliable and discriminatory, easy to perform? Even if the selection is not perfect, I am looking for reducing the number of strains to sequence (for identity confirmation).
    Harleen Kaur Dhaliwal · Institute of Chemical Technology, Mumbai

    Sir, what could be the reason for not getting halo formation even after 48 hours, although the biochemical tests shows 2+ for coagulase and positive for thermonuclease.

  • Seshank Mutya added an answer in Command:
    Can some one help me with VMD commandline?

    When ever i type any command specified in vmd tutorial i end up having having a error saying for example..invalid command name "within". I specifically wish to use WITHIN command and need help with it in selecting atoms at specified distance and finding contact residues.

    Seshank Mutya · Birla Institute of Technology and Science Pilani

    was a great help...thank you Navneet. It worked perfectly. If i could also get naming of the residues which i couldnt find the option any where.

  • Rachid Rouabhi added an answer in Peroxisomes:
    In case of peroxysomes separation is there any simple procedure or protocol?

    in case of peroxysomes separation is there any simple procedure or protocol?

    Rachid Rouabhi · Université de Tébessa

    thank you very much dear Parimal

  • Murat Tiryakioglu added an answer in Weibull Distribution:
    Can any body help me to learn how to fit drug release data into Weibull Function in Excel?

    Hi all. I need to fit my drug release data into Weibull function to know about the mechanism of drug release.

    The formula for weibull function is F = 1 − exp(−atb). where F is the drug fraction released at time t, and a and b are constants. b, as a shape parameter, is characterized as exponential (b = 1), sigmoidal (b >1), or parabolic (b < 1).

    Can some one help me HOW to fit or put my drug release data into this formula using microsoft excel sheet?

    Murat Tiryakioglu · University of North Florida

    I am a materials engineer so please take my answer with a grain of salt.  But here is what I would do:

    1. Rearrange the equation so that


    2. Take double natural logarithms so that


    3. Conduct regression analysis between as "ln(-ln(1-F))" as your Y variable and "ln(t)" as your x variable.  Slope will be b and intercept will be "-ln(a)".

    Good luck!

  • Neil J Calkin added an answer in Set Theory:
    How many subgroups of $S_n$, the symmetric group on a set of $n$ elements?

    $S_n$ is the set of all bijective maps from a set of $n$ elements onto its self. It is well known that $S_n$ is a group under composition of maps. How many subgroups of $S_n$, the symmetric group on a set of $n$ elements?

    Neil J Calkin · Clemson University

    Sloane's online encyclopedia of integer sequences has a some information on the number of permutation groups on n elements.  See the link


  • Spyros Tsiftsis asked a question in Variational Analysis:
    Do I need to standardize my data prior to a canonical variates analysis?

    Hi all,

    I am about to perform a canonical variates analysis in order to study the multivariate patterns of size variation of several Himantoglossum individuals belonging to different and a priori determined populations. So, I would like to ask if I need to standardize my data as in a PCA analysis.

  • Hanno Krieger added an answer in Organ Specificity:
    What organ specific normal tissue effects most limit current therapy?

    What non-economical aspects of radiotherapy are currently limiting the advance of more effective radiotherapy?

    What problems and limitations are limiting the efficacy of modern radiotherapy?

    Hanno Krieger · retired from Justus-Liebig-Universität Gießen

    just to give a short hint. The cancer tissue related facts are the oxygene effect and the diferent sensibility in cell phases. The limiting factors for the surrounding tissue are the needed repopulation, the repair and the redistribution in the different phases and the revascularisation of damaged tissues. If you are interested in short compact presentations have a look at some textbooks eg Sauer or Krieger.

  • Enping Hong added an answer in Dendritic Cells:
    How can I improve the purity or positive rate of dendritic cells?

    When we isolate the dendritic cells from mouse bone marrow, how to improve the purity or positive rate of dendritic cells?

    Enping Hong · Yale University

    Are you culturing bone marrow derived DCs from the bone marrow extract (adding GM-CSF and/or IL-4 for 7 days)? If so, you should get a lot of CD11c+ cells at the end of your culture. You could purify those cells by using a CD11c+ positive selection kit (StemCell Technologies).

  • Chithan C Kandaswami added an answer in Cancer Metastasis:
    What is the exact role of fibroblasts of tumor tissues in promoting cancer metastasis?

    What is the exact role of fibroblasts of tumor tissues in promoting cancer metastasis? 

    Chithan C Kandaswami · University at Buffalo, The State University of New York

    PI3K-Akt signaling is crucial for progression and metastasis of malignant tumors, and it has been documented that the Akt substrate, Girdin, an actin-binding protein, which regulates cell migration, is expressed and activated by Akt phosphorylation in cancer-associated fibroblasts (CAFs). The cross communication between tumor cells and CAFs (also denoted as activated fibroblasts) plays a vital role in the regulation of tumor promotion and progression, angiogenesis, invasion and metastasis.  Fibroblast activation protein α (FAPα) is a transmembrane serine protease that is strikingly expressed in CAFs in more than 90% of human epithelial neoplasms. 

  • Mina Soudi added an answer in Hydrological Modeling:
    Is it possible to construct a physical base model for shallow and wide lakes and hydraulic environments?

    Is it possible to construct a physical base model for shallow and wide lakes and hydraulic environments?
    For computational modelling of wide and shallow , which conceptual hydrologic or physical base hydrologic models do you propose?

    Mina Soudi · Urmia University


    Yes, that is. There are a15 km causeway in the middle of the lake  construction of a  long Causeway is to be an additional cause which eliminates the natural circulation of the water and redistributes sediment deposition around the lake.

  • Gwynn Alcorn added an answer in Plagiarism:
    What percentage (maximum) of plagiarism is generally allowed in a review paper?

    I want know about what percentage of plagiarism is allowed to make a review paper acceptable in journals.

    Gwynn Alcorn · Dalhousie University

    As a writer, journalist and editor for more than 40 years, I assure you that plagiarism - unless it is in quotations to make it clear you are quoting some other writer - is never acceptable.  The answer is zero, unless you attribute stealing someone else's words to them, and make that clear - this is not your work.