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  • How much increasing CO2 into the atmosphere affects the global temperature?

    As we all hear recently that CO2 concentration into the atmosphere has increase (as far as I remember) 390 ppm. Keep in mind that the report mentioned that the critical concentration of CO2 must not exceed (as far as I remember) 350 ppm. The question is: how much will this deference (i.e. 350 to 390 ppm) affect the global temperature?

    Martin B. Stolpe · ETH Zurich

    Regarding the "borehole-temperature" papers:


    On a small spatial scale, the time when a warming signal emerges from internal climate variability (that is the time when you are confident that the warming is signicantly stronger than the natural variability) occurs later than on a larger scale. That is because internal variability tends to cancel out on a larger scale. The studies you cited only try to reconstruct temperatures in North America, but not global temperatures.

    Later, Pollack et al. (1998) took all the availabe borehole temperature reconstructions (also the two you cite Mohamad) and thereby have a more global view of the changes. Their results are clear:

    Analyses of underground temperature measurements from 358 boreholes in eastern North America, central Europe, southern Africa, and Australia indicate that, in the 20th century, the average surface temperature of Earth has increased by about 0.5°C and that the 20th century has been the warmest of the past five centuries.

    Pollack et al., (1998), Climate Change Record in Subsurface Temperatures: A Global Perspective, Science

  • Thomas Murray asked a question in Cats:
    Has temperature been shown to influence domestic cat behaviour patterns?

    Has there been much research investigating whether cats behave differently under a natural range of temperatures.

  • Tennie Videler added an answer in HSQC:
    How does NMR sample impurity impact HSQC quality?

    Hello , everyone! I have one question. I have one NMR protein with 10KDa with a degradation about 5% . Can I acquire such sample NMR spectra for structure calculation?
    Besides this, I want to know,how many percent NMR sample impurity can be tolerate in NMR HSQC. I saw one paper said that if a impurity is a very larger protein when target protein only 10KDa, it can be ignore? Is it reasonable?
    For such impurity, I think that it will affect our assign signal. Maybe sometimes, very low percent impurity can give some peak strong intensity. Thanks a lot!

    Tennie Videler · University of Cambridge

    I agree completely with Ute and Matthew on all points made, especially the need to optimise the protein purification. One aspect to consider is that the larger protein you are co-purifying may well be co-purifying because it binds to your protein, which would really interfere with your spectra quality and ability to analyse it.

    To asses the amount of degradation compare HSQCs in between the 3D experiments you run but it would of course be ideal if there was as little as possible.

    Good luck and have fun.

  • Why does the pH rise during fermentation with Pichia pastoris MutS?

    Hi guys,

    I have a P. pastoris MutS phenotype which express very well in shaking flasks. I was trying to scale up the culture in a fermentor.

    The culture was behaving normally for most of the fermentation process, but as soon as I started the methanol feeding (after a DO spike to make sure all the glycerol was consumed) the pH started to rise and the acid pump worked for the whole methanol feeding process.

    I took samples at different time intervals and check them for protein expression. What I noticed is that the protein started to express as soon as 3 hours after the induction, then the expression increased in the next hours to a peak expression at 9 hours of induction. After that the cells were expressing less and less until the end of the fermentation. 

    Comparing the expression level of the peak in the fermentor (9 hours) and the expression in flasks for 48h, in the fermentor I anyway got 5x less protein than flasks.

    Do you have any idea how to improve the expression?

    Why the pH of  the culture was increasing during methanol feeding?

    Decrease in protein expression, could possibly due to no more nitrogen source in the medium?

    The medium I used was the "Basal salt medium" as described by the invitrogen guidelines and the only nitrogen source was the ammonium hydroxide also used to keep the pH at 5.0

    Thank you very much for your help,


    Fergal O'Meara · University College Dublin

    HI Marco,

    Just to clarify - you say you use NH4OH to control pH and that the "acid pump worked for the whole methanol feeding process". I assume you mean that the pump was still functioning and NOT that it was pumping NH4OH in culture continuously, which would of course explain rising pH?

    Assuming no mistake with addition of NH4OH then rising pH in Pichia culture indicates that the cells are stressed/dying. A good idea is to take samples and monitor OD readings - they should be increasing all the time, though Muts strains will grow only slowly on MeOH because they are missing the more efficient of the 2 AOX genes as Frank Hoger said.

    Also as Abiola pointed out the first thing to look at is MeOH conc in your culture. MeOH build up to toxic levels (~5% v/v) is more likely with Muts strain because they obviously metabolise it more slowly. If you don't have a way to measure it directly then a good indirect way is to periodically switch off MeOH pump and see what happens to dO. Ideally MeOH input should just match demand and when you switch it off you should see a dO spike within 1 min or less. If you don't see a spike turn off MeOH until you do and then reduce the rate of addition.

    Assuming you include some N in initial batch recipe then I think it is unlikely that you are running out of it in first ~9 hours

    hope that helps

  • Can the phosphorus fertilization alleviate the effects of Cu toxicity in plants?

    Can the increase of P content in plant provide the formation of a Cu-phosphate complex within the roots? Then, could this increase of P content reduce Cu translocation to the shoots and alleviate the symptoms of Cu toxicity?

    Vítor Gabriel Ambrosini · Federal University of Santa Catarina

    Dear Shah and Nguyen, thank you for the answers.

    In my master's degree, I'm studying the effect of liming on alleviation Cu toxicity in young vines and black oat. Liming is a good alternative because precipitate Cu and also increase Ca and Mg content in soil, which can also assist in the alleviation of toxicity. Furthermore, liming is relatively cheap.

    The articles of this study are not published yet. But our results show that liming to raise soil pH to 6.1 alleviated the Cu toxicity in young vines and partially to black oat. So, to black oat could be necessary a higher dose to raising pH a higher level. However, this could result in another problem, such as nutritional imbalance.

    So, in cases like this should be found another alternative to alleviate the toxicity. It could be a compost or a biochar. Could it be also a P fertilization?

    Well, why P? Because in our region (Southern Brazil), farmers usually perform phosphorus fertilization in vineyards. Could this assist in the alleviation of Cu toxicity?

    There are reports of alleviation of metal toxicity (including Cu toxicity) in plants by P. But, where is the primary effect of P on alleviation of toxicity: in the soil or within the plant? Can the increase of P content within the roots reduce Cu translocation to the shoots?

  • Iara Dasilva added an answer in Renal Fibrosis:
    How can I quantify fibrosis in a stained slide under polarized light using Metamorph?

    I am using picrosirius red staining for quantify renal fibrosis under polarized light through Metamorph software. I am having difficulty about steps to do a journal.

    Does anyone know to use this software?

    Iara Dasilva · Fundació Puigvert

    The journals are as MACROS, but I already know how to do it. thanks.

  • Nikola Ilankovic added an answer in Stress:
    Do you believe all active substances increase in stress conditions?

    we have some examples which indicate active substances( percentage and yield/m2) increase in normal condition

    Nikola Ilankovic · University of Belgrade

    Stress is o normal, physiological reaction in adaptation on exogen and endogen influences.

  • Guenter Grundmann added an answer in Geology:
    What are the benefits of teaching geology in the field?

    I believe we are trying to improve skills, knowledge and attitudes.

    Guenter Grundmann · Technische Universität München

    Dear Jacqueline,

    Sorry, let me add one more of the most important benefits of teaching geology in the field.

    The student learns to collect from a certain area of the field representative samples that are not too big but not too small for the subsequent tests in the laboratory.

    Each sample must be very carefully selected and documented because it is a unique piece of nature.
    Anyone can learn to treat Nature Objects with particular care and to give them special attention.

    Best regards,


  • Pradeep Kumar asked a question in FOREX:
    Why we are getting linear predicted values when ever we use garch predict function in matlab? Please suggest some relevant stuff?

    I am working with FOREX volatility forecasting using GARCH using MATLAB. I am getting linear predicted values rather than correct innovations. please help me in this context and suggest me some relevant stuff.

  • How can I learn modeling with IC engine module in Ansys Fluent?

    hi all, I want to learn modeling with IC engine module in Ansys Fluent software.for practicing its own tutorial i should have these two files:

    (injection_mass.prof , tut_comb_sect.x_t)

    how can I find them?

    Is there anyone who can help me?

    thanks for ur attention.

  • Harshavardhan Khare added an answer in GaussView:
    Stacking energy calculation using gaussview and gaussian?

    Can anyone give me a detailed description of how to do a stacking energy calculation in gaussian using gaussview???I will be really thankful if the description contains details starting from the drawing of molecule...I am new to this area...

    Thank You

    Harshavardhan Khare · Indian Institute of Science

    If I understand correctly, by the term 'stacking' you refer to so called 'pi stacking' interactions. Then this paper might be useful-


    The authors have calculated binding energies of dimers of pyrene and naphthalene diimide.

  • Anil Gaikwad asked a question in Brown Adipocytes:
    Please suggest protocol for differentiation of Mesenchymal stem cells in to brown adipocytes?

    I have surfed internet there are many protocol with different chemicals used for differentiation induction. please provide components of differentiation induction media?

  • Marcin R Przewloka added an answer in Antibodies:
    Could anyone recommend a good anti-RFP antibody that is suitable for IF and raised in either mouse or rabbit?

    It would be great if you could also suggest a protocol for IF. Thank you very much.

    Maria Grazia

    Marcin R Przewloka · University of Cambridge

    I used Rb anti-RFP from Abcam (#ab62341-100) in the past and was satisfied with the outcome. Good luck!,  MP

  • What is the problem with an internal thoracic artery pre-contracted with NE and ANG II?

    What is the problem of the internal thoracic artery that feeds the mammary, when precontracted with NE and ANG II that leads to wobbling of the curve as you see in the attachment images.

    Can anyone tell me what the problem is?

    Jeremy P T Ward · King's College London

    As Ismail says, preconditioning before the experiment by challenging with 80 mM [K] (isotonic substitution for Na+) for 5 mins a couple of times often helps stabilising vascular preparations. However, I am not sure that the oscillations you are seeing really count as a "problem" - except to the experimenter - as they are very common in isolated arteries depending on type. Mesenteric arteries often exhibit the same sort of response to agonists. People often just don't show it in publications!

    Apart from the high[K+] challenge, you may be able to minimise this by 1) being very careful not to over-stretch the artery whilst tying up, 2) by carefully removing as much adventitia as possible, and 3) by leaving the preparation to equilibrate after tying up for 30- 60 min before starting the experiment. Some artery types just seem to be more twitchy than others (it is not a problem generally in pulmonary artery, but is in mesenteric).  

  • What are your experiences in stimulating interest and curiosity in science phenomenon among your students to increase motivation to learn science?

    Have you tried to increase awareness and interest in science phenomena. Does stimulating interest and curiosity in science phenomenon increase student motivation to learn science? I must admit that I become a scientist partly due to a great curiosity about science phenomena. What are your experiences in stimulating interest and curiosity in science phenomenon among your students to increase motivation to learn science?  What are the results?

    Ajay Singh · IIT Kharagpur

    I have also made an answer to @Eraldo's thread.

  • Payman Davoodi-nasab added an answer in Emulsions:
    How can one create o/w emulsion of a powder?

    I need to create o/w emulsion of a powder which is soluble only in polar organic solvents. I used TX100 and I was highly succesful. Unfortunatly, now I have to replace the TX100.

    I tried a mixture of tween and span (20) and every time I add the emulsifier-oil phase to the water the powder precipitates.

    What should I do? change the method? Change/add emulsifiers/surfactants? Any suggestions would be gratefully appreciated.

    Payman Davoodi-nasab · University of Tehran

    Dear Sivan
    In order to have a emulsion or dispersion or suspension of polar organic solvent, you have to focus on HLB parameter of the surfactants. I mean as the HLB decreases the solubility in organic phase raises. So, using Span85 is really recommended. The HLB is near 1.5 and completely soluble in oils.
    Best regards,

  • Fang Xia added an answer in Hydrothermal Synthesis:
    Where exactly do I get TiO2 crystals in the autoclave after solvothermal synthesis?

    Solvothermal synthesis is based is a method that utilizes phase reactions in non- aqueous or aqueous (hydrothermal synthesis) media at high temperature and pressure to crystallize materials directly from solution.

    I am confused by the information in the net. They distinguish solvothermal and hydrothermal methods that are basically differ from one another just by type of solvent. However, there are a million set ups of this methods found:

    1. At the beginning I thought that this method is based on the dependence of solubility on temperature- with decreasing the temperature, the solution became saturated and crystals appeared. So, that is just like one grows CuSO4 crystals in water.

    2. Then I found that hydrothermal synthesis is implemented in autoclaves and that there are 2 temperature zones, so, it is just like in the first method, but crystals will slowly crystallize in one part of the autoclave. (I found this description in WIKI)

    3. After that, I found a book in which the autoclave contained a seed crystal and it seemed like crystals were obtained from saturated vapour.

    4. However, no seed crystals or zoned autoclaves are used in papers. A typical procedure is to load precursors and solvent into an autoclave, then it is closed up and heated for tens of hours, after which it is naturally cooled to room temperature. The next step is commonly skipped in papers, scientists just analyse TiO2 crystals, but where exactly in autoclave do I get TiO2 crystals in solvothermal synthesis? Where are the crystals formed? In addition- at what step do they form?  Whether when we cool the autoclave or when it is kept at high temperature? Why does it take so long to prepare crystals?

    Fang Xia · The Commonwealth Scientific and Industrial Research Organisation

    Well, we can do in situ XRD in our lab-based diffractometer, but synchrotron-based in situ XRD provides better quality dataset, especially for hydrothermal which involves a broad sovent peak.

  • Bala Murugan s added an answer in ModelSim:
    How to use library ieee_proposed file?

    Good noon to all. I am a newer in VHDL I don't know how I can use ieee_proposed library files. I got some errors while compiling my project in modelsim altera se6.5e. In my project I have used these files: library ieee_proposed; use ieee_proposed. Fixed_pkg. All; while using this library file I got below errors. ** Error: C: /altera/10.0/fixed pt. VHD (1) : library ieee_proposed not found. ** Error: C: /altera/10.0/fixed pt. VHD (2) : (vcom-1136) unknown identifier "ieee_proposed". ** Error: C: /altera/10.0/fixed pt. VHD (4) : VHDL compiler exiting I searched to clear this error in many way. Anyone told to create library as ieee_proposed. I did it. But I got same error. Please give me clear steps for clear this error. Thank you.

    Bala Murugan s · VIT University


  • Will recent warming hiatus with respect to mean temperature continue or not?

    2014 became the warmest year on record, without a strong El Niño. The so-called global warming hiatus (1998-2012) are widely concerned. In the following decade, global mean temperature warming will continue to slow down, or will rise much more rapidly than in the "slowdown" period? What are main physical causes responsible for inter-decadal changes of mean temperature?


    You say "we have increased the atmospheric level of CO2 by 10% since 1998...and the number of people causing it by 20%. Should be no surprise that the environment has changed with seven billion of us on our way to 10 billion. What did we expect? The climate to stay still?" But the climate has stayed still. We call it a hiatus.

    But the question is not about the cause of global warming or of the hiatus. It is what will happen next?

    There is the possibility that this could be similar to another branch of Earth Science - earthquakes.  The pressure in a fault builds up until there is a sudden relase of energy and an earthquake happens. The same could be happening with the climate, with the hiatus corresponding to the period between earhquakes. The increase in CO2 is building up a stress in the climate system that will be relased when a tipping point is passed and an abrupt warming ensues.

    In a non-linear system such as that we have with the climate, that seems a more likelt outcome to me, than 1) entry into a new ice age, 2) a continuation of the hiatus, 3) a gentle rise in tempeature similar to that which happened during the 20th Century.

  • Eugeniusz Sajewicz added an answer in Cermets:
    How are the wear rate and friction coefficient affected by increasing sliding velocity?

    How is the wear rate and friction coefficient of WC based cermets affected by increasing the sliding velocity in dry sliding pin-on-disc wear test (velocity is of the order of 0.5 to 2 m/s)?

    Eugeniusz Sajewicz · Bialystok University of Technology

    For many material connections wear rate and coefficient of friction show some inversion in relation to sliding speed, i.e. for low speed we observe high friction and wear, then increasing speed leads to deacreasing of tribological characteristics (some optimal state of tribological system), and finally rapid increase tribological charakteristics are seen when the speed icreases.

  • Per A Albertsson added an answer in Radiolabeling:
    Why won't my HiTrap desalting column perform as well as its NAP-5/10 counterparts in purifying radiolabeled antibodies?

    Same media in both columns (GE Sephadex 25). Pre-treated with BSA in the same way. Flowrates within limits stated for he HiTrap. Still bad perfomance. The outcome is a pure product but a lot of activity stick to the column, even when starting with an already purified material...

    Per A Albertsson · University of Gothenburg


    Good question, 

    And  on behalf of the TATgroup Many Thanks to all of you engaging and giving valuable input to the problem.

  • What is the most appropriate method for overcoming seed dormancy whose tegument shows mechanical resitance to the embryo growth?

    I am studying the dormancy process in seeds that have mechanical resistance to embryo growth or the crossing by water or oxygen. Considering also that it is recalcitrant seeds, which methods can be used to overcome dormancy?

    Tashinga Donemore Mudzengi · Tobacco Research Board

    What  dormancy is inherent in that species?,  that will help us to answer the question correctly. Maria seems to suggest there is physiological dormancy then if it so the after-ripening or moist chilling are the pragmatic approaches which can be used to enhance germination as well GA-3. Attached, is the document by baskin and baskin that might help in understanding the dormancy in seeds and the classification as well as methods to alleviate dormancy. 

  • Jane Rogan added an answer in Dialysis:
    I am look for strengths approach research that has been done regarding compliance in health care, specifically dialysis treatment/medication?

    I'm not looking to find out why patients are non-compliant - there's plenty of that, but who has asked the "compliant" patients how they manage to do that.

    Jane Rogan · University of Central Lancashire

    You may find these interesting if you haven't already seen them.

  • Nidhi Verma asked a question in Calculations:
    How we can calculate catalyt loading into mol % ?

    calculation of mol %

  • Carla Even asked a question in Coating:
    Does anyone know a better way to coat plates for MDA-MB-231 cells?

    I'm coating with Poly-L-Lysine and after fixation with PFA most of the cells are gone.

  • Patricia Ryser-Welch added an answer in ACO:
    What kind of information can be regarded as the heuristic information in ACO algorithm? 

    See above

    Patricia Ryser-Welch · The University of York

    It would be interesting to see the different ACO that hyper-heuristics or genetic improvement would produce in terms of specialisation against each optimisation problems.

  • Omar Elkadi added an answer in Intercalating Agents:
    How DNA alkylating and intercalating agents are selectively antineoplastic agents and don't have antifungal or antibacterial activity?

    During anticancer chemotherapy, which usually involves DNA alkylating or intercalating agents, the patients become at higher risk of infection due to reduction of the WBC count, and damage to physical barrier. So, it is likely for the patient to easily get infected, specially in leukemia. Why the DNA acting antineoplastic drugs don't protect him from bacterial and fungal infection, why they don't act on the DNA of these microbes as they act on human cells.

    Omar Elkadi · Cairo University

    Dr. Juskevicius, I am exactly talking about the example u have mentioned. In my hospital, we don't have the enough facility to sufficiently isolate the leukemia patient; thus, infections is normally expected at the nadir point. However, I found it difficult to understand how the microbes survives the long exposure to chemotherapy, which seems to me more aggressive than convential antibiotics, if they are actually effective against microbes. I have to exclude the dimensioned immunity, as antibiotics are still effective.

  • Stefan Berendts added an answer in XRD Analysis:
    Why is it necessary to convert ADS data to FDS data in an XRD pattern?

    Why is it necessary to convert automatic divergence slit data to fixed divergence slit data for phase quantification in XRD?

    Stefan Berendts · Technische Universität Berlin

    Hi Anjali,

    the best thing is to measure your sample directly with fixed slits (FDS-measurement). Then you will avoid any inaccuracy by the (mathematical) transformation of your ADS-data into FDS-Data (takes normally just twice the measuring time to get good data). Additionally, Dominique provided you a nice overview in the link how the XRD powder pattern is effected by the diffraction angle.

    One question: What kind of XRD machine do you use?