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Peptides

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  1. Hi all, I have a question which I'm currently quite confused on. To begin, a saturation binding assay on intact wild type AtnR cells using the tritiated AtnR angatonist [3H]DPPX has been performed. [3H]DPPX is added to cells in increasing concentrations in the presence or absence of cold competitor DPPX to determine the non-specific binding (NS) and total binding (TB), respectively. Each tube contains 15 cells in a final volume of 500µL. DPM (disintegrations per minute) results are obtained for each concentration. From this, I must calculate the specific binding for each concentration. To calculate the specific binding I'll first have to calculate the non-specific binding, and then minus this from the calculated total binding. However, I don't understand how to obtain these from the DPM results? Any help on this would be much appreciated.
  2. Hello all, I have a question regarding a recent practical I performed using a hemocytometer during my Immunology class. During this practical I dissected out a mouse spleen, to which I added PBS. A 10ul sample of this suspension was then mixed with an equal volume of trypan blue and loaded into the haemocytometer chamber. My cell count was as follows: White cells: 203, Blue cells: 42. 100ul of the original spleen suspension was then added to 1ml red blood cell lysis buffer. As this is a hypotonic solution which lyses red blood cells, I expected to see more dead cells. However, when mixed with trypan blue and loaded into the haemocytometer chamber, I saw no cells at all. I tried repeating this section of the protocol but again observed no cells. Why might this have been? I'm guessing that maybe all the cells were red blood cells and therefore lysed, but then wouldn't I have at least seen some blue cells, definitely more than before lysis? If I did happen to obtain a cell count after lysis, but the total count was different to that obtained before lysis, could this just be a result of the different samples of spleen suspension taken? Lastly I'd like to calculate the number of red and white cells in the spleen. To do this, I'm assuming I would take the difference between the blue cell count before lysis and the blue cell count after lysis to be the number of red blood cells in the sample. The white cell count would then be the white cell count after lysis. Does this sound correct? Also, I'm confused on and really have no idea about how I would then use this to calculate the number of red and white cells in the spleen Any help on this would be much appreciated.
  3. Enthalpy of formation is the enthalpy change when one mole of compound is formed from its constituent elements under standard conditions, all reactants and products in their standard states. The delta symbol signifying a change The heats of formation for nitrogen is negative, and wouldn't the formation of oxygen be positive? Just the opposite of what's written if the reaction were to go in the reverse direction?
  4. Hi guys, I need some help working out this question It says, calculate the standard enthalpy of formation of NH3 from the following data H2 + 1/2 O2 = H2O. DeltaH=-286kJmol^-1 4NH3 + 3O2 = 2N2 + 6H2O. DeltaH=-1537kJmol^-1 My first thought was to draw out a thermochemistry cycle, but I'm not sure whether the enthalpy values given are for formation or combustion. Does it matter which of the two they are? Also, how would I go about working this out? The previous two questions asked for the equation of the first law of thermodynamics, which is deltaU=q+w and and equation that relates internal energy, enthalpy, pressure and volume, which would be deltaH=deltaU+PdeltaV Any help would be much appreciated
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