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  • Jeffrey R Brender added an answer in Proteins:
    Hi, I got only one-broad peak around 220 for the Far-UV spectra of my protein. Does any body have similar experience?

    I noticed only one broad peak around 222 for the Far-UV spectra of my protein. It containes mostly alpha-helics but the 208 peak is missing. I have tested CD for both MBP-fusion protein and the 80%-purified protein. But still the same pattern. When I tested MBP alone I got a normal alpha-helics spectra though!

    Jeffrey R Brender

    Without looking at the spectrum I cant be sure, but I agree with Javed and Brigette that the program is likely aggregated and a mixture of random coil/beta sheet. A conformational change is not that uncommon during aggregation. Is there any visible sediment if you spin the protein down? Do you have access to a size exclusion column or or dynamic light scattering instrument? Is there an enzymatic activity for the protein? A DOSY NMR experiment can also tell you the exact size. 

  • Norbert Holstein added an answer in Plant Taxonomy:
    What plant is this?

    The plant is a small tree with imparipinnate compound, glabrous leaves. The bark is grey. Fruits are 4-loculed or by abortion of 2 ovules/seeds they produce 2 seeds. The plant is growing in Australia. 

    + 3 more attachments

    Norbert Holstein

    This looks like a Meliaceae (mahogany family) but as Arvind Singh mentioned, flowers would be very helpful.

  • Rick Rupinski added an answer in Philosophy of Religion:
    Why does religion become first port of call during social and economic strife?

    Why does religion become first port of call during social and economic strife?

    Within religion, why does a large chunk of the population not go deeper into orthodox religion but head instead towards these new age guys with their superficial cosmologies and simplistic solutions?

    Rick Rupinski

    To answer the former question: I think it is because when life becomes ripe with strife, then worry and anxiety begin to creep into the mind. At this point, the overwhelming questions of life become very important to people. Religion provides answers to these questions.

    To answer the latter: that seems to have become very, very prevalent in the later half of the twentieth century (though not to say that this is when it started). People have an urge to follow spirituality, but they are looking for some specific things. These things can be as simple as eating pork to making free love and having orgies (there was actually a case of this in I believe the 60's where a man was actually bought a home and flown in from India to preach these ideals). Many people have begun to distrust the old religions as well. I think the greatest marvel and example of this phenomenon that you identity in the last sentence of your question is: Scientology. People pay to be re-programmed and purchase salvation-- or Operating Theta levels-- by trading their lives and money to the church.

  • Pamela Kaithuru added an answer in GHG emissions:
    How can Africa Benefit from the Cop21 Agreement?

    The International Community has adopted a commendable Agreement on tackling climate change in Paris last December. While the deal has a number of ambiguous provisions and non-binding provisions, the document is very progressive and has galvanized the consensus of all the UN member states, perhaps for the first time ever when such concurrence is achieved at this scale. 

    The question is how can Africa, with virtually no contribution to global warming in terms of GHG emission and given its very limited capacity to implement the Intended Nationally Determined Commitments (INDCs) benefit from the Agreement and take active role in its realization of the Paris Agreement in the coming 15 years.

    Kebede Kassa Tsegaye, PhD

    Team Leader for the Formulation of the IGAD Regional 

    Climate Change Strategy (IRCCS)

    Pamela Kaithuru

    Thanks Prof for this thought provoking and great way to seeking solutions facing mankind globally and more so Africa. To add my voice to this, the COP21 Agreement has Intended Nationally Determined Contributions (INDC) which were 'it is presumed' arrived at after lots of consultation  of all stakeholders. Today I was privileged to  participate in a forum in Kenya that was looking at the sectors priority adaptation actions and it was eye opener to me. In the light of the above, if each African country could map out all stakeholders, engage all the relevant stakeholders at all level, such that virtually every player conceptualizes the impacts of climate change, their role in mitigation and even adaptation and therefore commits to within their jurisdictions to do the bare minimum then these collective targeted and coordinated efforts will be impact-full.

    Regardless of Africa's  contribution to global warming in terms of GHG emission,  we are not spared  the impacts; besides often times we are adversely affected. It is for this reason that I perceive we need to be clear with the INDC's, map out available resources and ensure proper and optimal utilization of the 'meager' resources to get bigger impacts. I liken this with an 'individual' that will have to cut their dress according to the size of material/cloth they have at times not according to their size, literally. We can redesign our strategies to ensure that the 'cloth read resources' available are able to fit our size of challenges. Besides, employing 'traditional' methods, culturally appropriate since there is no 'one size fits all' for Africa. This of course includes reaching out to partners to mobilize resources available for climate finance globally. 

  • Luis Felipe Llanos Reynoso added an answer in Philosophy Of Science:
    Under which conditions does new scientific knowledge enter the social sphere and become common sense?

    Can someone recommend me an article or book concerning this question? In different words: What are social acceptability conditions for scientific knowledge? I already scanned through Kuhns Structure of Scientific Revolutions but I somehow feel like he stays in the scientific ivory tower and does not discuss the question of how scientific revolutions influence the civil society, create social movements or change the behavior of people.


    Luis Felipe Llanos Reynoso

    Perhaps one of the most fundamental characteristics to insert one new scientific knowledge enter the social sphere and became common sense is the formation of knowledge-based networks.

    I recomend you the next old paper


  • Harveen Natarajan added an answer in Neurobiology:
    Has anyone used GFP tagged AAV in vivo?

    I'm interested being able to visualize AAV particles in the brains of mice following systemic injection of AAV. GFP-VP2-AAV has been used in culture to visualize GFP particles in cell nuclei, but is tagged AAV to large to transverse the BBB? Has anyone tried using a tagged AAV in vivo?

    Harveen Natarajan

    AAV-GFP is not too big, it can cross the BBB. Depending on the serotype, it will get into the brain. I think AAV8 and AAV9 given via tail vein do get into the CNS. For your purposes an icv injection is probably best. You can buy cannulated animals from JAX or taconic. 


  • Deemah Dabbagh added an answer in Adeno-associated Virus:
    Virus particle purification?

    I am transfecting T293 cells with pAAV (adeno-associated virus vector). How can I purify the recombinant virus after transfection?

    Deemah Dabbagh


  • Anne Ebenau asked a question in Value of Life:
    How to relate 1) life values and 2) hope and spirituality?

    Dear everybody,

    Currently I am working on a review about life values of elderly people suffering from incurable cancer. From the literature, values like honesty, continuity, dignity and the like came up. Obviously to me, they are life values. Besides these concepts, two other concepts arose: hope and spirituality. Both important of course, but I don’t know how to integrate them and link them to life values. Are they in some way a source of which life values derive, sources of nurturing life values or life values in themselves? I can't get my head around it.

    Does somebody have any ideas on how: to relate life values on the one hand and hope and spirituality on the other? Or does anybody have suggestions for literature about this?


  • Jeremy Pronchik added an answer in ELISA:
    Glass based ELISA assay?

    I would like to compare the polystyrene plates we use for ELISA assays to glass. Does anyone have experience either passively coating or covalently linking a capture antibody to a glass surface? I have found methods for covalent linkages, but would like something simpler.


    Jeremy Pronchik

    great, thank you!

  • Thomas Andl added an answer in Luciferase Assay:
    Is cloning a 9kb 3'UTR for luciferase assay necessary or cloning the regions of 3'UTR-miRNA interaction is sufficient?

    Hi, the gene of my interest has a 3'UTR of nearly 9.8kb. I am planing to perform luciferase assay for studying the miRNA-target interactions. So is it okay if i could clone  those regions where miRNA is binding to 3'UTR (acc. to the insilico tools) or should I use any other stratergy for the same. Please suggest if I could study the miRNA-3'UTR interaction through any other assay.

    Thomas Andl

    That is a good question. Although the 3'UTR luciferase assay is regarded as one of the gold standards to show that a gene is regulated by a specific microRNA, the test may involve some un-physiological parameters that can make the assay a little bit artificial. Therefore, I would say, since the assay tends to be artificial, it is probably okay to just clone a fragment of the 3'UTR that contains the putative binding sites for the microRNA.

    Alternatively, you could use site blockers (for example, http://www.exiqon.com/mirna-target-site-blocker). I have not used this approach but it seems a viable alternative approach, that combined with a 3'UTR luciferase assay of wild-type and mutant 3'UTRs, should convince most readers that the putative target can indeed be a target of your microRNA. Whether it is a relevant target is another question.

    Hope this helps.

  • Aldo Costa Valarezo added an answer in Diabetes:
    Has any one articles on complications of hypertension and diabetes from follow up (cohort studies)?

    what factors speed or delay complications?

    Aldo Costa Valarezo

    There are many cohort studies that analyze diabetes and hypertension complications (INTERSTROKE, INTERHEART, PURE, ATAHUALPA project, NOMAS, ROTTERDAM, and more..). It is well known that in diabetes appropriate glucose control delays the complication and disease progression. In hypertension one can simply think that normalizing blood preassure levels migth be the solution. But, the recent guidelines approach is to give a number, a level below which we can reduce the complications and progression of the hypertension. Unfortunately, this topic is on debate now. With the pubblication of SPRINT trial 140 mmHg appears to be a better option for a BP target on patients without diabetes and stroke-free patients. There is a lot of controversy behind this trial. This year the NOMAS study mentioned above, published a paper of 1700 patients aprox. followed up for 13 years. This study demostrate that less than 140 mmHg is a better target for stroke prevention in hypertension patients. I reccomend to read this study which I adjunct to this answer plus the SPRINT trial. Observational study have a major problem: RESIDUAL CONFOUNDING. But I still believe that observational studies give us a population perspective of health problems and we must thake them in consideration when we write guidelines. I also invite you to read about the ATAHUALPA project which is a cohort study with a native rural coast population in Ecuador (the country where I come from). Publications of macrovascular complication of diabetes and Hypertension are now available on Medline. You can search on Pubme for papers. Microvascular complications publications are coming soon.

    Best Regards,


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  • Harveen Natarajan asked a question in Hepatocyte Isolation:
    How do you calculate how many animals are needed for hepatocyte isolation?

    I need to estimate (with power calculations) how many animals would be needed for my experiments with primary mouse hepatocytes. Assuming good yeilds. 

  • Vahid Javaheri added an answer in Electron Backscatter Diffraction :
    What is the best EBSD system available on market right now?

    What is the best EBSD system available on market right now? In terms of post processing software capabilities, stability, performance, user interface etc.

    Vahid Javaheri

    I agree with Soud, I also believe that Oxford is the best and its sof. is very user friendly.

  • A. J. Escribano added an answer in Animal Physiology:
    What is the current status of research on CLA in ruminants?
    In the field of CLA supplementation in ruminants, it is believed that we have passed all the borders of research in the field of CLA feeding to dairy cows. Actually what we know is limited to the fact that CLA is causing milk fat depression in dairy cattle.

    What do you think about the points which are not addressed or less investigated in this area?
    A. J. Escribano

    Dear Behnam,

    It is needed to assess the efficiency of incorporation CLA in animal products so that it is sustainable. Sometimes, great efforts are made on this, obtaining poor results.

    When I say 'sustainable' I mean: feed efficiency, real need for human health (taking into account current intake of CLA and recommended dose), farms' profitability (cost-effectiveness for the farmer).

    In this regard, I would like to connect this question with one I recently made (attached).

    Interesting question, Behman.



  • Lutz von Wangenheim added an answer in Circuits:
    Who knows the properties and the working principle of this circuit?

    Recently I came across with the shown circuit.

    It has some interesting properties. Is there anybody who has used such a circuit already? Both opamps are assumed to be ideal.

    Lutz von Wangenheim

    Dobri - I have some problems with your calculation.

    At first, in your calculation what is V1 and V2? Opamp output voltages or the voltages at the top and bottom of Vdiff?

    Secondly: You assume a gain of two for the second opamp which has POSITIVE feedback. I don`t think thisd is allowed. This is a typical case of an unstable gain stage which is stabilized through an additional negative feedback path. And, therefore, we must perform another calculation (Note: The result is correct).

    My approaches (Vo1 and Vo2: Opamp output voltages):

    A) Simply using the superposition principle (for three voltage sources Vdiff, Vo1 and Vo2) ) we arrive after some manipulstions at the correct result (for all R being equal):


    B) We can apply Blacks feedback formula for the closed-loop gain Acl,2 (opamp2).

    For this we (temporarily) define a new input Vin at the grounded resistor R2

    Acl,2=Vo2/Vin==Hf*Aol/(1-Aol*Hr) with open-loop gain Aol.

    Note that this general formula is not tailored specifically to negative feedback . The feedback function is (Hr=Hr+Hr-). We have two feedback branches with different sign: Hr+ = +R2/(R1+R2) (R1and R2=Pos. feedback resistors) and Hr- = -(1+Vdiff/Vo2).

    After inserting these expressions into the closed-loop gain formula for Acl,2 assuming Aol infinite and setting Vin=0 we arrive at

    Vo2=-Vdiff(1+R2/R1)  and  Vo1=Vdiff+Vo2=-Vdiff*(R2/R1).

    C) Loop gain (Stability):

    It is possible to show that the second opamp (with a pos. feedback path) always has unity negative feedback (ideal opamps without additional phase shift). Hence the net feedback always is negative for any ratio R1/R2. However, as soon as the opamps are real with finite gain and additional phase shifts the amount of positive feedback R2/(R1+R2 )must be reduced to ensure stability.

  • U. S. Rao added an answer in Correlation:
    Which methodology is best to determine the hedge and safe haven effects of gold on stock?

    Hedge is an asset negatively correlated with stock on average and if this negative correlation preexists in a crisis period, will it maintain the status of safe haven?

    U. S. Rao

    Traditionally gold has been considered as a safe haven asset. In long term gold works as an inflation hedge. This can be checked by taking 50 or more years of data. When volatility increases in markets $ price increases as investors reduce their risk by shifting to $. If $ falls or is weak they shift to gold. Those who do not have access traditionally shift to gold when economic uncertainty increases or markets crash or currency depreciates. The relationships can be built by identifying the major reasons, and studying the parameters over a long period of time.

  • Christopher Alcantara added an answer in Indigenous People:
    What are the effects of colonialism, capitalism on indigenous people?


    People relations 


    Please give ideas and post journal articles

    Christopher Alcantara

    Check out my co-authored book, "Beyond the Indian Act: Restoring Aboriginal Property Rights" which examines the intersection of capitalism and Indigenous peoples with respect to individual property rights:


  • Sergio Torloni added an answer in Hematology:
    What's the pathophysiology behind iron overload among non-transfusion dependent sickle cell patients?

    Cardiac & Hepatic Iron overload are prevalent and understandable in transfusion-dependent SCD patients. however, it has been observed and reported by many recent cases about iron overload among non-transfusion dependent SCD patients; is there any studies or hypotheses about the justification of this overload?

    Sergio Torloni

    RBC's have a standard life of 120 days.  Stored blood will have a life of 50 days. Sickle cell crisis will cause cells to deform and block capillaries. HbS cells will have a tendency to lyse.and release Fe, and K.  Also, of interest, LDH increases in these patients. One would think that this would be due to LDH 1 and 2 isomers. Interestingly enough, LDH 5 is elevated indicating an ischemic event more prominent than hemolytic event.  Also, SCD patients will require transfusions. Transfused cells have a 50 day lifespan and therefore will release more iron.  Washing the cells helps to some extent but not much. Attempts have been made to use "neocytes", namely younger cells with heavier specific gravity. This is a time consuming and expensive process. It takes about 5 units of whole blood to come up with one unit of neocytes. This practice has been abandoned many years ago.  The iron released by the RBC's will deposit in the liver, heart and pancreas causing serious deterioration of function in these organs. Chelation therapy with  Desferoxamine, and more recently Ex-Jade, are the treatment o fchoice. This is not something without its own risks... I hope this helps.

  • Alessandra Bastone added an answer in Exercise Science:
    What should be the ideal method for measuring intensity and total calorie of physical activity?

    There is an endless list of studies on effect on physical exercise on metabolic disorders like NAFLD. Most have used self reported questionnaires especially in retrospective studies which have an inherent recall bias. What should be used for a prospective study in this field? Pedometers or accelerometers or any other instrument? 

    Alessandra Bastone

    Dear Preetam Nath,

    I've had a very good experience using Actigraph GT3X to measure habitual physical activity in older adults, and the measurements showed a good relaionship with VO2 peak measured directly during an incremental shuttle exercise testing. Also, I have had no problems with compliance using the GT3X device, and it's very simple to manage.

    Best Regards,


  • Noor Ul Hadi added an answer in Performance Management:
    I would like help in invesigating problems related to performance appraisal systems and survey questions to assess such in an organisation?

    hi I would like to find out the topical issues related to performance management systems (effectiveness) in organisations and carry out a case study on my organisation. I would greatly appreciate any tips for the kind of questions I can include in my survey.

    Noor Ul Hadi

    You might be interested in...

  • Ranae Dietzel added an answer in Abiotic Stress:
    Dear researchers colleagues, is there any review of water use efficiency (ET based/consumptive/conjunctive) of crops/cropping systems?

    Water use efficiency is not conservative, as it varies under differential inputs as well biotic/abiotic stresses, but normally we describe WUE under potentially grown condition, in a way to assess the total water needs of crops/cropping systems. 

    our interest always lies in knowing WUE for crops/important cultivars/cropping system in terms of evapo-transpiration, ET + drainage (in case of rice), conjunctive water use (in terms of use of poor quality waters) or applied water.

    Within our RG group, there are eminent water management experts, and the question is of collation of these imp efficiency factors in order to management our resource inputs.


    Ranae Dietzel

    Naveen,  although it is written for corn and soybean systems, we have a recent publication on systems WUE here: http://onlinelibrary.wiley.com/doi/10.1111/gcb.13101/full and available on my profile page.  Our definition takes into account ET, drainage, and runoff.  Hope it helps!

  • A. J. Escribano added an answer in Ruminant:
    Effects of CLA on ruminant reproduction?

    does anyone knows or worked about effects of CLA on ruminant reproduction?

    A. J. Escribano

    Dear Roghayeh,

    Here you have two papers that directly answer your question.



    + 1 more attachment

  • Fabrizio Guzzetta added an answer in Phosphors:
    What does mean quantum efficiency of phosphors ?

    In luminescence analyses, what does mean the quantum efficiency of the phosphor ? and how we can calculate it ?


  • Suhas Dinesh added an answer in HFSS:
    Related to RF simulations in EM solver tool HFSS?

     How we define ground signal in HFSS? Suppose we have two cylindrical conductors. I want to give signal to one of conductor and ground to the other conductor. what will be different port configurations used for four ports of two conductors?

    Suhas Dinesh

    Draw a Waveport on the entire cylindrical surface touching both the surfaces. Now draw an integration line from one surface to the other. The integration lines are used for finding voltage by integrating the Electric Field lines (Flux).


    For multiple modes like TE20 or TE30 you may draw more than a single integration line in the specific direction from the surface of one conductor to the second one.

  • John Mcclimon added an answer in NEXAFS:
    What sp2 carbon hybridization reference samples for EELS in TEM?


    I've been planning to do some sp3-fraction determination for doped a-C:H samples in the TEM.  I'm pretty familiar with this measurement using NEXAFS, but have never attempted it in a TEM. Looking through the literature, it seems there is not a consensus choice for what sp2 carbon standard sample to use for the reference measurement.  The angle-sensitivity of HOPG makes that a poor choice for EELS.  I've seen suggestions to use fullerenes, which I'd use it there was an easy way to procure TEM coated grids with it; I won't be able to thermally evaporate it onto a grid myself.  I've also seen that microcrystalline graphite and some forms of carbon black might work as well.  Does anyone know of a supplier that sells an isotropic fully-sp2  carbon sample suitable for TEM imaging, or how to prepare one yourself without any specialized equipment you wouldn't find in a university sample preparation facility?  By any chance, is the lacey carbon that comes on many TEM grids ~100% sp2?  I can't find any information about the structure of support grid carbon.



    John Mcclimon

    I would (and will, actually), but the TEM spatial resolution is crucial to what I am doing.

  • Michael Delannoy added an answer in Hybridoma:
    My hybridomes have been dying, How to grow hybridomes which have been stored for 10 years?

    Hello guys, I'm trying to grow some hybridomes which were frozen 10 years ago, I have been trying to grow them in RPMI + 10 % of FBS, but after one week they start to die, do you have some recommendations or a nice protocol which has worked for you with difficult hybridomes to grow.

    Michael Delannoy


    When I was at Cold Spring Harbor Labs we used to grow the hybridoma cell lines in 96-well plates. Here are some strategies:


    Good Luck

  • Guy Roemer added an answer in Groundwater:
    I am having some difficulties in importing boreholes data into Groundwater Vistas. My boreholes are in UTM format. how do I add them to GW vistas?

    The boreholes are in UTM and I dont know how to import them. Also when I import a shapefile to GW vistas, it does not come to same position as my grid. Kindly help.

    Guy Roemer

    I took a quick glance at your Excel file.  You need to delete all columns that are not needed in Vistas.  Only import name, x, y, water level, top of screen, etc.  Some of the fields have a "/" or spaces.  Save the modified Excel file as a CSV file and then import that file.  Then, tell Vistas which column is x, which column is y, etc.

  • Giulia Morsica added an answer in Pharmacy Practice:
    What should be the expiry date of medicines (specially Tablets) when its removed from the original containers?

    The repacking of medications is largely growing, due to the concept of unit dose system of distribution of medicines.

    Giulia Morsica

    This is a very curious but interesting question. IThe expiration date is the good time if the tablets are not crushed and well conserved (ie not in contact with liquids or meal )