Search results for query: *

  1. Y

    Peritoneum, abdominal walls (anterior/posterior )

    Keep in mind that all abdominal organs are covered with visceral peritoneum which is continuous with parietal peritoneum and is just given a different name because anatomists like to give new names to the same structure in different places. So if you were to use your suitcase analogy and...
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    Chemical Safety - Storing Ammonium Nitrate

    Your first stop should be to look at the MSDS for storage of any chemicals.
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    Actin Treadmilling

    Going from memory here. Actin monomers and polymers are polar structures, meaning their structure shows unique characteristics at each 'end.' This polarity gives rise to the difference in polymerization and depolymerization kinetics at either end. Also, don't forget that actin monomers have a...
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    News RIP Drakkith's PC

    That's because your PC wasn't all the way dead, it was only mostly dead.
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    Today I learned

    This was yesterday, but it will have to do. Yesterday I learned that Fourier Transform Infrared (FTIR) spectroscopy was born from the Michelson interferometer used in the famous Michelson-Morley experiment.
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    Gnuplot: reflexion of a graph in a quadrant to the other

    Just a guess as I haven't used gnuplot in a while, and haven't ever really used the splot stuff. Can you do something like, splot "data.dat" using 1:2:4 notitle, "data.dat" using ($1*-1):2:4, "data.dat" using 1:($2*-1):4, "data.dat" using ($1*-1):($2*-1):4
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    Dangerous bacteria

    The idea in Ygggdrasil's post, although not explicit in the matter, covers the respiratory tract as well. As we are constantly breathing, all tissues and organs involved with respiration are interacting with the outside world constantly. It only makes sense that some bugs would find themselves a...
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    Multi-centre trial = better than single-centre?

    I think Choppy is spot on here. I would be a bit surprised if you needed to cite research about designing a multi center study. It is more or less the statistics which favor such designs in order to recruit an appropriate amount of participants to increase statistical power...
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    Laws of Thermodynamics

    In an idealized case where the walls of the container are rigid (so no work can be done) and perfect insulators, then the first law of thermodynamics tells us that the temperature would not change. Unfortunately, perfectly adiabatic systems do not exist as far as I know and are useful as...
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    Biochemistry of Relaxing effect of Chamomile?

    I suggest you check out PubMed and/or PubMed Central and look for some reviews or relevant papers. The latter link will provide papers and reviews which are available to the public free of charge while the former will show papers which may or may not be behind pay walls. If you have access to...
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    Voltaic (Daniell )cell

    Not trying to insult you, but your posts will be much easier to read if you refrain from posting one long sentence. I have two questions for you assuming I understood your post. 1. In your hypothetical metallic zinc bar + ZnCl2 setup, where would the electrons go? 2. If you are correct in...
  12. Y

    D and L Convention

    It is a rotation around the axis defined by the C4-C5 bond by 60°. Bonds are allowed to rotate, and do so very quickly without changing stereochemistry. Imagine the three substituents on C5 as the legs of a tripod, with the camera or whatnot as the rest of the molecule, and you may be able to...
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    Alternate CPR technique

    I believe the OP meant the muscle pump. Although the wikipedia article seems to refer to some effects on arterial blood flow, it is more commonly thought that the muscle pump only aids in venous return via the little "check valves" that are found in our veins. Thus, it is unlikely that you can...
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    Carbocations vs carbanions

    You are mixing up quite a few things here and it is very difficult to give you an answer. Let's clear up some terminology and ideas here. Carbonyl carbons do not form carbanions. In fact, carbonyl carbons have quite a bit of carbocation character, thus they are attacked by nucleophiles (think...
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    Aldol Condensation

    That looks better. As far as your question goes, refer to the second part of my first post. Good and bad may be used as though they describe a binary phenomenon, but in reality things are not simply yes/no or good/bad. They all fall on a spectrum, so perhaps better terms would be better/worse...
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    Beer's Law and Graph

    Hint: A = εbc ⇔ y = mx + b Hint 2: Because the b term (y-intercept) throws many off. What would the absorbance be if C = 0?
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    Aldol Condensation

    The mechanism you drew is not correct in that the lone pair on the carbanion will not "kick off" the hydroxyl group as there is a methylene group between the two. Re-draw the mechanism from scratch to get a better idea of this reaction. As far as the hydroxyl leaving group, think about what is...
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    Organic Addition Reactions

    I agree with your answer but I would advise you to learn the mechanism and work through it. Most importantly to learn what the key intermediate is and why a certain product may be formed instead of another. Your answer, I believe, is correct but the question is relatively straightforward...
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    Can the heat of combustion only be found experimentally?

    Yes, heat of combustion is usually determined experimentally. It is a pretty trivial measurement by today's standards and very accessible. I think you may have it a little backwards. To determine the heat of formation of butane, you need to have graphite and hydrogen gas in their standard...
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    Conversion of tertiary haloalkane

    A majority of introductory O-Chem is explained by charge/electron density as influenced by the Inductive Effect and Resonance Effects. Although I'm not exactly sure why radicals become more stable when they are "spread out," I have just come to accept this fact...
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    Statistics Linearity Question

    R2 may be one way to do it but remember that is just a measure of how "far" away your linear fit is from the data (in the R2 it is squared to get rid of negative numbers and somehow normalized such that a perfect fit gets you a value of 1). You can have a lower R2 from noisy data which are still...
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    Conversion of tertiary haloalkane

    Why would you assume that the rate of addition of bromine to the terminal carbons will be so high as to make free radical bromination not useful for this conversion? Think about the mechanism and selectivity of free radical bromination. What type of carbons are favored to form radicals in these...
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    Organic Addition Reactions

    You need to show a bit more effort than just randomly guessing one of the choices. For the first one, can you talk about what type of reaction it is? What is the "key" intermediate which will determine the products? What factors affect the formation of the products from the "key" intermediate...
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    Why Tetrasubstituted Alkenes More Stable Than Tri/Bi/Mono

    You are correct about about the cis- and trans-alkene case being readily explained by the increased steric strain for the cis-alkene case. When it comes to alkene stability in regard to substitution, the theory is meant to explain the trend that a more substituted alkene will have a smaller...
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    Dumb Question: What Happens to Alcohol When it Evaporates?

    As was mentioned already, the alcohol doesn't disappear. It will diffuse away as a gas. Also, you will not evaporate ONLY the alcohol but a mixture of the alcohol and water which is enriched in alcohol due to the lower BP of the alcohol. At a certain point you will come to a mixture known as...
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    Electron affinities

    I think you will find this website ( discussed exactly the issue you are asking about.
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    The Inductive Effect and Electronegativity

    Carboxylic acid acidity is better explained by resonance structures of the anion produced by deprotonation. The negative charge can resonate between both oxygens thus lowering the charge density and stabilizing the anion. I'm not sure if that is what the book explanation is trying to get at but...
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    What is needed to read the DNA?

    Hunt around at Tons of databases there. There is a learning curve involved when trying to find and then analyze the data contained, but it isn't too difficult.
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    Mixing Solutions: Understanding Volume & Enthalpy

    What is the definition of an ideal solution?
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    Wisdom Teeth Removal - Sedation Type

    Most miserable experience of my life. I had two impacted lower wisdom teeth done 1 week apart. About an hour after the surgery, when the local wore off and my pharmacy screwed up by NOT filling out my pain meds, I experienced the worst pain ever. I actually sobbed. Then a week of pain, swollen...
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    Chirality of naproxen

    Your chiral carbon is attached to: 1) A hydrogen. 2) A carbon which is attached to 3 or so oxygen atoms (because m.ultiple bonds are counted as equivalent number of single bonds, from memory) 3) a carbon which is attached to 3 carbon atoms (same as above). Can you do it now?
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    Units being used in the graphs for ψ and radius (in nm) and ψ^2 and ra

    My limited understanding of wavefunctions is that you cannot physically interpret a wavefunction in and of itself. The square of a wavefunction is interpreted in a probabilistic manner such that the square of the absolute value of psi can be interpreted as the probability of finding the particle...
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    Rotation of double and triple bonds

    It is not that rotations around pi bond can't happen, it is just that there exists an energy barrier which is difficult to overcome under typical pressure/temperature conditions. You can take a look at the UC Davis ChemWiki for some discussion on the MO Theory take on this. My simplified...
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    What are the origins of humor and laughter?

    I was just taking a guess and trying to guide further research/discussion. Here is something interesting I found in a 5min Google Scholar search using "laughter evolution" as search terms. It is only an abstract but may shed a bit of light to aid in further discussion/research...
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    How does this structure exist?

    Well, you could technically draw many more resonance structure than simply three. It doesn't mean that all of them will be contributors to the true nature of the actual molecule though. I guess for the typical O-chem question where there it is implied that the most stable resonance structures...
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    Chemistry Resonance Structures for a Certain Molecule

    I don't see any atoms changing in the first picture you uploaded, but I could be tired (or stupid). Are you perhaps referring to the pi electrons shifting within the ring? Technically they have shown ALL possible resonance structures with the dashed lines and partial charges in the first...
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    Chemistry Resonance Structures for a Certain Molecule

    Your structure in red is the first structure they drew. Are you referring to some other resonance structure?
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    How does this structure exist?

    See: Allylic Carbocation. In your case it is "doubly allylic" so you should have several resonance structures available. Can you draw them now?
  39. Y

    Choosing filter paper to extract an organic compound from HCl using gr

    I'd imagine it depends on the concentration of HCl. Erring on the side if caution, you're best bet is likely to check with the manufacturer.
  40. Y

    Choosing filter paper to extract an organic compound from HCl using gr

    Sounds fine to me. If it were me, and I were working on an tested protocol, I'd check (qualitatively or quantitatively) the filtrate to get an idea of how well it worked.
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    Choosing filter paper to extract an organic compound from HCl using gr

    I don't know that plain old filter paper would work on a soluble component of a mixture. Typically if you want to filter something in solution, you need to use ultrafiltration techniques (which have limits to how small the pores can get AFAIK) or find a way to separate the unwanted component...
  42. Y

    MPN method for CFU

    I agree with both of the statements you made and would proceed accordingly if I were doing this.
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    Most Exothermic Combustion of Hydrocarbon

    So did you settle on a final answer? Has your instructor mentioned anything? I'd dig around for actual experimental measurements if I were you, otherwise I'd go with a simplified analysis of axial interactions and call it about even. EDIT: Found...
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    Most Exothermic Combustion of Hydrocarbon

    Look at your picture again, flipping the ring changes the equatorial to axial and axial to equatorial but it does NOT change the numbering of the ring carbons nor does it change the "up" or "down" assignment. Notice how the hydroxyl is always on carbon #1 and is always "down" although the flip...
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    MPN method for CFU

    We can't just offer you an answer, we are here to help you work through your problem and actually learn something. So I will reiterate my questions above. Do you have any thoughts or reasoning for averaging or not averaging the two measurements? In an ideal world, do you think there should be...
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    RIP arildno: Gone, but never forgotten

    This is a very sad day. My deepest condolences for the loss of such a special person. I hope that he found the peace he sought. RIP arildno, you are immortalized in the memories of those you touched and the knowledge which you shared with the world.
  47. Y

    Preservation of protein structure in electroblotting

    Proteins aren't rigid structures and protein dynamics are now thought to play a large part in the function of enzymes and such. You can try to google terms like 'induced fit' to see that enzymes do indeed wobble around and change conformation quite a bit to perform catalysis. Without writing a...
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    What are the origins of humor and laughter?

    I think you may be oversimplifying the situation. Laughter is a part of socialization, which is self evidently a trait that has been selected for in human and animal evolution. Socialization allows for humans (and other animals) to protect themselves as well as share resources, skills etc...
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    MPN method for CFU

    What do you think you should do? Do you have any reason to suspect doing it one way or the other? Also, when you say averaging the counts do you mean the raw data from each tube? Just to be clear, are you saying you will calculate, for example, (42+4)/2?
  50. Y

    Protein electrophoresis algorithm

    Have you eliminated the possibility of differential dye binding? Also if you aren't using a light box type of instrument, then you have all sorts of things to worry about. For example the lighting varying from place to place on the gel, as well as the inherent differences in the pixel...