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  • What are the possible reasons for peak splitting at higher injection volumes in HPLC?

    While I was calibrating my HPLC injector linearity parameter, I was facing the problem of peak splitting at 60, 80 and 100 uL inj vol. The column I used was C18 150 mm x 4.6mm x 5u. I tried washing the column with 100% organic followed by 50% organic..but the result was same..column pressure was stable.

    Kaliyan Ayyavoo · Reliance Industries Limited

    Use 250 mm column, otherwise set up less concentration for analysis. Your 150mm column would not be enough theoretical plates for separating the analyte of your column performance might have reduced (blocked active site)

  • Vivek Hamse added an answer in pH
    How do you run a Native gel on proteins with pIs ranging from 6-9?

    I would like to do a native gel on a small (9 kDa) basic (pI-9.5) protein, and we will be looking to resolve different isoforms that have different PTM's.  These PTM's will alter the pI significantly (by 1-2 pH units), so we would need an electrophoresis system that covers a range of pH's, like 6-9. I read that acetic-acid urea gels are good for basic proteins, but could that be used in this case?  Any ideas would be appreciated!

    Vivek Hamse · Sri Jayachamarajendra College of Engineering

    I think that Acetic acid - Urea might denature your protein of interest. So its better run a Acidic Native gel. U can find the protocol on net. If not i give sent u the protocol. Plz give me your Email ID

  • Morteza Shabanzadeh added an answer in MATLAB
    How can I obtain the lowest value of levelized cost of electricity of power plant using an artificial neural network using Matlab?

    Good morning everyone,
    I work on the optimization of solar thermal power plant using ANN with Matlab software, to obtain the minimum value of the levelized cost of electricity (LCOE), I already simulate some cases (100 case) for using the inputs and output (target) in this ANN.
    My question is which are the next steps to obtain the min value of LCOE ?
    Thanks in advance.

    Best regards.

    Morteza Shabanzadeh · Tarbiat Modares University

    Dear Taqiy,

    There are so many optimization methods and tools to solve your problem. GA and PSO are popular among university students but they are meta-heuristic and thus you cannot be sure the result is the absolute optimum.

    As an engineer, I recommend you using GAMS software which has so many solvers able to optimize your problem based on mathematical rules and not meta-heuristically.

    See  http://www.gams.com/


    Morteza Shabanzadeh


  • Arezoo Eftekhary asked a question in Alumina
    Can anyone explain me how I can prepare the sol or suspension from amorphous alumina?

    I am working on amorphous alumina

  • What is the best modality of delivery for hydrocephalus with Spina bifida + meningomyelocele?

    G2P1L1 36 wks gestation (first FTND), admitted with leaking since 5 hrs. 3 cm dilation. Antenatally diagnosed with Hydrocephalus with Spina bifida + meningomyelocele. BPD is 11.2 cm. What should be the best modality of delivery?

    Giuseppina Comitini · Azienda Ospedaliera Santa Maria Nuova di Reggio Emilia

    Counseling with parents. Prognosis. Vd or cs.

  • What does it mean if there is no hysterious loop in a magnetic nanoparticle (Iron oxide)?

    I have synthesized Iron oxide capped with a polymer having size ranging from 10-15 nm and measured magnetic character via VSM at room temperature. What are the possible application of such material,except biomedical field.?

    Greig A. Paterson · Chinese Academy of Sciences

    Dear Santosh,

    As many people have pointed out what you are most likely measure is superparamagnetic (SP) behaviour. At room temperature, the hysteresis should have an "S" shape where both the descending and ascending loops coincide and yield zero coercivity. 

    This behaviour arises when magnetic particles are above their blocking temperature and thermal fluctuations are large enough to over come the coercivity of particles. At room temperature iron oxides < ~20-30 nm are in the SP state, but this varies a little depending on a number of factors (e.g., the composition and degree of magnetic interactions between particles).

    If you have access to a machine capable of measuring at low temperatures (10-300K), you can measure the hysteresis behaviour as a function of temperature. What you will find, is that a low temperatures your hysteresis loop will broaden and behave more like a single domain (SD) loop. This is because you have cooled you sample below its blocking temperature and thermal fluctuations are no longer capable of overcoming the coercivity of the particle at laboratory measurement timescales. For your particle size, I would estimate that you need to below ~100-150 K for your particles to begin blocking, but this depends of the grain size distribution.

    As others have pointed out, magnetic nano-particles can have many applications, with biomedical applications currently being one of the most prominent. They are also very useful for exploring magnetic behaviour and properties. Because these particles can be blocked and unblocked below or at room temperature they are particularly useful for exploring time-temperature dependence of magnetic behaviour, which with particles that are SD at room temperature requires heating to high temperature and runs the risk of thermal alteration.

  • Bharath B.R added an answer in Virtual Screening
    Structure based virtual screening?

    Can anyone clarify, in structure based virtual screening among inhibitor molecules, does minimum binding energy indicates that the docked molecule has shown better binding or better inhibition? If yes then, what does it means if its binding energy decreases when it is combined with substrate molecule?

    An inhibitor molecule prevents the substrate from binding to an active pocket and thus inhibits the product formation. Where as in the absence of inhibitor substrate will get converted into product.

    Bharath B.R · NMAM Institute of Technology

    More the BE lesser the interaction, Lesser the BE more interaction

    Binding Energy = [(1) + (2) + (3) - (4)]


    (1) Final Intermolecular Energy,
    (2) Final Total Internal Energy,
    (3) Torsional Free Energy,
    (4) Unbound System's Energy

    As Unbound System's Energy is more the binding energy will be less so as the ligand binds the Unbound System's Energy will increase so you can expect minimum BE

    Hope helps

  • Ebrahim Sotoudeh added an answer in Fish
    How does limonene influence fish performance?

    How does limonene influence fish performance?

    Ebrahim Sotoudeh · Tarbiat Modares University

    So far, I have not seen study on effect of limonene on fish. But most of studies on mice and rats indicated that these supplement have antioxidant and anti-inflammatory Properties. Also, in humans used as a supplement for lowering blood triglycerides and weight reducing.

  • Marco Marano added an answer in Metformin
    What do you think about metformin treatment in case of renal insufficiency?

    There may be a debate in using metformin treatment in diabetes type 2 if associated with renal insufficiency. What about using metformin in renal failure if no diabetes?

    What do you think about that?

    Marco Marano · Maria Rosaria Clinic Pompeii Italy

    I fully agree with Amritlal Mandal, I would like to add another piece for discussion. Metformin cannot be used if GFR below 30, but in hemodialysis patient lactic acidosis is not a issue because blood gas analysis is often performed for acid base and electrolyte monitoring, hence lactic acidosis may be prompty and early recognized. 

  • What is the best percentage protein gel for a 16 KDa protein sample using Western blot?

    I am working with a 16-KDa protein on 4-20% gradient gel in my Western. I tried both monoclonal and polyclonal antibodies. Every time I am getting sharp band with a molecular weight matching ~20 KDa, particularly with polyclonal. Is this anything to do with change of low molecular weight marker or switch different percentage of gel? Or any other suggestions would be highly appreciable.   

    Santosh Karnewar · Indian Institute of Chemical Technology

    histones -17 kda ,  i am rergularly doing 12% gel bands are good if u want u can do 12-13%.

  • Eun Jung Sohn added an answer in Autophagy
    What are the functions of NH4CL in autophagy?

    what I know is that NH4cl is the blocker  of fusion of autophagysome and lysosome, and increases LC3B. However, when the cells were treated with drug and NH4CL, LC3B was decreased or no change., Can I explain that the coumpounds funciton in blocking the fusion of autolysome? but, p62 was not increased..  

    Eun Jung Sohn · Kyung Hee University

    Thanks!  I might try it with  bafilomycin ! 

  • Mobile cloud computing open issues

    What are the open issues in mobile cloud computing, android and provider api?

  • Nicholas Sontag added an answer in Climate Change
    Is it time we forget climate change & focus on the 'Human Dimension'? Is it not obvious that nature can heal itself, if only left alone?
    A lot of hue and cry is made about climate change and the environment in general. Public and private money is poured into research to study its effects on the environment, sustainability etc. Should we study nature or ourselves? Human activities have been found to have a direct correlation to climate change and its impact on the environment(I=P x A x T, the Ehrlich and Holdren equation), in spite of what some complacent sections say to protect their own self interests. It is pretty obvious that it is human beings who need to be studied. We hardly know about Human nature. We can scarcely predict human behavior. We need to find out why we think like we do and why we do what we do and why, in spite of all knowledge and wisdom, consume more than what we need, in the form of addictions to consumption and imbalance not only ourselves but also the family, society and environment around us.. Humanity is directly responsible for all the imbalances occurring on the planet. Yet we refuse to take responsibility and instead focus on climate change, or fool the public exchequer with a 'breakthrough in renewable energy just around the corner'. We scarcely know what drives human beings. If we had known, all the imbalances around us would have had solutions. Are we blindly groping in the dark of climate change because we don't know the answers to our own nature? Is it not high time we focus on what makes us human, correct our consumptive behavior and leave nature to take care of climate change? Why focus effort on 'externals' when the problem is 'internal'- 'me'? Aren't we addicts denying our addiction and blaming everything else but ourselves? The reactions we have right now can be grouped into: 1. I worked hard to earn my money. I can use it and consume as I please. Climate change is for the birds. Material consumption and more gives me happiness. 2. Life is competitive. Only those who struggle will survive. Its a 'winner takes all' situation. Otherwise we are all dead as a dodo. I would like to safeguard my future by saving as much as I can for the future. 3. Life is all about cooperation with your fellow beings. 4. Invest in more technology that will ease the current logjam in resource availability. More technology can mean more for everyone and we can continue to consume. 5. Invest more in climate change study. 6. Invest in legislation to prevent ourselves destroying the environment. 7. Invest in studying Human Nature and use that to educate and bring about legislation aimed at understanding addictive consumption and prevention. 8. More perspectives are welcome! IMHO, We don't need to save the World. It is enough if we save ourselves from ourselves. The need of the hour is not vain glorious interventions, but self-restraint and self-correction!
    Nicholas Sontag · Earlham College


    I believe what drives human nature is the innate want for happiness. I don't think many people would argue with this. What does vary, however, is the path or plan towards happiness. The idea of happiness takes on so many different shades and flavors. Consumerism paints a sanitized, itemized, narcissistic picture of happiness. Growth is necessary and therefore more is good. Consumerism also disconnects; 'big box' stores sit in cement wastelands forcing the fact that someone labored to grow or produce these bananas and those flip-flops onto a sticker or tag that is just as soon trashed and heaped in some unknown, unimportant place. And what more can be expected? How else can we act? Where are the options and outlets? 

    I see a people sick with themselves. Thoughts upon millions of thoughts tangled inside each individual skull. But these thoughts have no ill-intention; in fact, I believe they are of the best intention- those seeking happiness. How can these knots be untied and strung from mind to mind, city to city, and country to country to weave a web that tells of true happiness: community, connection, conversation, a collection of energy with the sole intention of loving and caring and learning?

  • Can we mix digestion buffers from different manufacturers in double digestion reaction?

    I need to digest my plasmid using BamHI and SacI. Unfortunately, the enzymes came from different manufacturer, Fermentas and Wako Nippongene respectively. I checked the buffer ingredients and they are quite different. I want to do double digestion by first digesting my plasmid using SacI then BamHI since the latter needs higher salt concentration. Any thoughts regarding this matter?

    Shridhar Kinkar · Gennova Biopharmaceuticals Ltd


    I agree with Juan... You can try these enzymes' compatibility in various digestion buffers and select the most suitable buffer. However... If you are preparing vector backbone for cloning then I'd suggest you to perform sequential digestion.

    Good luck :)

  • Does anyone know where we can purchase a CPD machine?

    We are planning to buy a CPD machine to extract tiny flies from alcohol without shrinkage of the specimens. Should you have any ideas about a heavy-duty CPD at reasonable price please send me the related information.

    Ebrahim Gilasian · Iranian Research Institute of Plant Protection

    Dear Yves

    Many thanks for your message included nice information on CPD.



  • Soumya Mishra added an answer in Pediatrics
    Can you please suggest a PUBMED indexed pediatrics journal?

    I want a pubmed indexed good pediatrics journal. the publication charges also should be less than 5000rs INR or better if free. I have tried Indian journal of pediatrics already. few other good journals are acceptable. not necessarily indian journal.

    Soumya Mishra · Jawaharlal Institute of Postgraduate Medical Education & Research

    thanks a lot Dr. Khaled

  • Ghanshyam G Tejani added an answer in Trusses
    How to find the natural frequencies of truss?

    I want to initiate dynamic analysis of truss structure to optimize its weight. Initial reading explore that it need natural frequencies. But I could not found how to get it. Could you please suggest or if possible share related materials?

    Ghanshyam G Tejani · RK University

    Dear Nils Wagner,

    Thank you very much,

    Would you please define f = np.sqrt(w)/(2*np.pi) # eigenfrequencies [Hz]

    What is np.sqrt and np.pi ?

    I think w,vr = eigh(K,M) should be [w,vr]=eig(K,M).

    And M = L L^T, Here what is L and T?

    You are requested to solve my difficulties 

    Thank you 

  • Shouxian Ma added an answer in Precambrian
    Does anyone have knowledge on the Hailstone Impression - looking for new examples?

    I want to ask if anyone knows any structures from the fossil record that could be considered as hailstone impression. We have already published some from the Neoproterozoic/Cambrian transition and simply looking for other examples. They could tell a lot about the early atmosphere it dynamics and climate zone distribution.
    Thanks for any respond.


    Shouxian Ma · Chinese Academy of Geological Sciences

    Dear Zbyszek,

    This is an interesting topic, which reminds me of the phenomenon I found in Precambrian strata of the North China a few years ago. There are lots of pits in a dolomite bed, these pits are filled with dark mudstone(just like the pictures show). I asked a couple of colleagues and was told of "hailstone impression". And then a new problem arises up, what is the climate like if the hail happened with carbonate which seems to represent a warm climate. Additionally, what kind of structure is it if there were not hailstone impression?

    + 1 more attachment

  • Can polyunsaturated fatty acids improve fertility?

    Can polyunsaturated fatty acids improve fertility?

    Ebrahim Sotoudeh · Tarbiat Modares University

    One of the main effects of these fatty acids on fertility is changing membrane fluidity . Long Chian PUFA resisting membrane packing and contributing to its fluidity. As membrane fluidity is thought to facilitate membrane - dependent functions such as receptor – ligand interaction, membrane transport, and membrane - bound adenylate cyclase activity.

  • Jeremia Perdana asked a question in Probiotics
    Pseudomonas as a probiotic

    Dear all,

    Some reseacher recommended me to use Pseudomonas Aeruginosa and Pseudomonas fluorecens to my probiotic for aquaculture (fish and shrimp), but i am still doubting about that, because those bacteria are pathogen for human. Anyone can suggest?



  • Amaresh Raichur added an answer in Nanorods
    How to estimate the amounts of two phases (co-existed!) of a material using XRD data?

    I was characterizing the e-beam deposited CuxO films/nanorods; and I found that Cu2O and CuO (or Cu and Cu2O) are co-existed during annealing at different temperatures, i.e. before turning into a single stable phase (of polycrystalline of the mentioned phase(s)). So, I was wondering if there is/are any method(s) to estimate or compare their amount in the mixed phases (for e.g. Cu2O and CuO).

    I have attached the XRD patterns of CuxO. Hope this will help to suggest whether we can use their peaks for estimation or not.  Your help will be much appreciated.

    Thank you.

    Amaresh Raichur · Indian Institute of Technology Bombay

    I can try in my spare time and i normally use MAUD and FULLPROF for analysis, i will let you know results of analysis (after my attempt for analysis).

    thank you, 

  • Sourav Biswas asked a question in Alkynes
    Can mesoporoes activate alkyne to deprotonation?

    i am currently doing coupling of terminal alkyne with mesoporous Cu doped manganese oxide. The coupling of alkyne is processing without presence of base. Where commercial CuO , Cu2O or manganese oxide cannot promote the reaction without presence of base. According to literature, the activation can be happened in absence of base in some cases like  Cu(I) in the system or some other activating group. So can it be the reason for presence of mesopores?

  • How can I perform an image classification?

    Hello. I can extract  SURF  features from images using matalb  but I can't perform classification on group of images using SURF.

    Could anyone tell me how I can use matlab to classify images depend on extracted SURF features?

    Thank you!

    Dear Dr Parul,

    i am still in beginning so any database will be welcome. 

    I try to apply LDA OR SVM classification 

    i  worked on birds database in the following link



  • Madhu Manish Raj added an answer in Motor
    What happens if the number of poles of a "BLDC Motor" is increased during the design of the motor?

    If the number of poles are increased for the "BLDC Motor" during its design, the torque density of the motor is going to be increased and also the iron losses are going to be increased eventually. Transistor losses also increases with the increase in poles of a BLDC Motor. Also higher PWM frequencies are required with more poles.

    If the number of poles are increased for the "BLDC Motor" during its design, the torque density of the motor is going to be increased and also the iron losses are going to be increased eventually. Transistor losses also increases with the increase in poles of a BLDC Motor. Also higher PWM frequencies are required with more poles.

  • Daxing Gao asked a question in CD8
    What percentages of CD4+ or CD8+ T cells are Tbet positive in spleen?

    I am trying to stain mouse spleen cells for Tbet. I wonder what percentages of CD4+ T cells or CD8+ T cells are Tbet positive in spleen of wild type B6 mice?

    Thanks in advance!

  • William Leibzon added an answer in GPU
    Can anyone help with installation of two GPU in my Ubuntu system?
    I am finding it very difficult to install both of these GPU in my system. 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 630M] (rev a1) Thanks in advance.
    William Leibzon · University of California, Irvine

    Here is my documentation on how to do it if you or anyone else still needs it:

  • Giulio srubek tomassy added an answer in Neuron
    Can anyone help with a large pyramidal neurons marker?

    I would like to quantify pyramidal neurons from the cerebral cortex. SMI-32 antibody IF let me select only a subpopulation of  them (PN-type I, theorically). Could anyone recommend me an antibody for pyramidal neurons? 

    Giulio srubek tomassy · Harvard University

    Try CTIP2, Abcam, 1:500. It will label the nuclei of all layer V subcerebral projection neurons, and at lower levels also those of layer VI PN.

  • Jedol Dayou added an answer in Piezoelectricity
    Can we replace ZnO in Cellulose-ZnO Hybrid Nanocomposite for better piezoelectricity?

    I came across a paper on piezoelectric material made from Cellulose-ZnO Hybrid Nanocomposite. This is very interesting work which can be found at http://www.ingentaconnect.com/content/asp/jbmb/2014/00000008/00000002/art00004. I have no background in chemistry so I'm hoping that a chemist out there might help. My question is, theoretically, can we replace ZnO with other metal oxide to increase the piezoelectricity of the composite?

    Jedol Dayou · Universiti Malaysia Sabah (UMS)

    Thank you Prof. John for the clarification. This is a good option to explore. Could you suggest a reference paper on how to growth titanate particles? By the way, I'm sending the mentioned paper for your reference.

  • If audio fingerprinting is a solved problem, what other areas related to content based search on audio are still open?

    I have read that audio fingerprinting is now a solved problem [1][2]. If so, what other areas related to content based search on audio are still open?

    [1] Van Balen, Jan. Automatic Recognition of Samples in Musical Audio. Master's thesis. Universitat Pompeu Fabra, Barcelona, Spain, 2011.

    [2] F. Kurth and M. Muller. Efficient Index-Based Audio Matching. IEEE Transactions on Audio, Speech, and Language Processing, vol 16, pp. 382-295, Feb. 2008