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    Understanding the logistics of oncolytic virotherapy

    I have questions about a particular paper: Oncolytic Poxvirus Armed with Fas Ligand Leads to Induction of Cellular Fas Receptor and Selective Viral Replication in FasR Negative Cancer The authors explain that they're using an oncolytic virus to deliver membrane-bound Fas ligand to cells in a...
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    Henderson-Hasselbalch & phosphate buffers

    This is an example calculation about the phosphate buffer system from my Biochemistry textbook. Homework Statement If the total cellular concentration of phosphate is 20 mM (millimolar) and the pH is 7.4, the distribution of the major phosphate species is given by pH = pKa + log10...
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    Approximate uncertainty in area of circle

    Homework Statement What is the approximate uncertainty in the area of a circle of radius 5.3 * 104 cm? Express your answer using one significant figure. Homework Equations A = pi*r2 The Attempt at a Solution Using the given radius, I found the area to be 8.8 * 109 cm2. And since...
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    H NMR of unknown sample (organic chem)

    Homework Statement Last week in organic chem lab, we were provided with an H NMR spectrum of an unknown compound with the formula C7H5NO3. I'm not terribly good at analyzing these spectra, but I've managed to figure out that I'm looking at 4-nitrobenzaldehyde. The only thing that's bothering...
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    Syn versus anti elimination

    Can someone please help me understand the difference between syn and anti elimination in terms of what they favor? My [extremely] limited understanding leads me to believe that syn elimination favors E2 since it mimics frontside attack, which will not work for Sn2 since there is no net-bonding...
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    Reasons for unusual infrared spectrum?

    In my organic lab we recently isolated and crystallized the natural product usnic acid from dried lichen. An IR spectrum of the crystals dissolved in mineral oil was obtained, but it came out looking a bit strange. The thing that's really confusing me is that there is no band that would be...
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    Estimating area with finite sums

    Homework Statement Use the midpoint rule to estimate the area under the graph of f(x) = 7/x and above the graph of f(x) = 0 from [1,25] using two rectangles of equal width. Homework Equations N/A The Attempt at a Solution So first I found \Deltax by using (b-a) / n and got (25 - 1)...
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    Calc - Derivatives and Differentiation of Logs

    Homework Statement I have a few problems that are giving me some trouble: 1. Take the derivative of xe-4x 2. Find dy/dx and evaluate the slope for the curve ey^3 - 2x4 + y2 = 3 at (8,0) 3. Find dy/dx and evaluate the slope for the curve e-y - 4 = x2 + 1 at (-2,2) Homework Equations N/A...
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    Chemistry Molecular Geometry: NH3

    Homework Statement I'm trying to figure out the electron pair geometry of NH3. I know that its molecular geometry is a trigonal plane, and it has 4 electron pairs total, including one lone pair. Homework Equations N/A The Attempt at a Solution Should the e- pair geometry be a...
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    Energy liberation in ionic bonding

    Homework Statement If removing electrons from atoms requires energy, and adding electrons to atoms usually liberates energy, then why is energy liberated when the ionic compound NaCl forms from the elements sodium and chlorine? Homework Equations None The Attempt at a Solution My solutions...
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    Sizes of atoms

    Homework Statement I have a few questions here that say to identify which atom from each pair is larger. One pair is Be and B, and the other is P and Cl. Homework Equations N/A The Attempt at a Solution I know that Be is larger than B, and that P is larger than Cl. I'm just...
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    Average rate of change

    Homework Statement I have just started my first ever calculus course, and I'm having a little trouble with a simple rate of change problem. It says: Find the average rate of change of the given function between the following pairs of x-values. The given function is f(x) = x2+ x The given...
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    Chemical Amount?

    Chemical Amount?? Hey guys, I'm looking for a little help with the whole concept of chemical amount. This question was posed during my intro chem lecture (assume a hydrogen atom's mass is 1 amu, and an oxygen atom's mass is 16 amu): How much oxygen does one need, to have the same number of...
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    One more trig identity

    Homework Statement I'm finally starting to understand proving trig identities, but I have just one more that I can't seem to figure out. secx - tanxsinx = cosx Homework Equations N/A The Attempt at a Solution Well first, I multiplied the tanx and sinx and came up with sin2x /...
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    Proving Trig Identities

    Homework Statement I'm not looking for anyone's pity, but I can't even begin to tell you how confused I am with this concept. My teacher spent all of five minutes teaching it to us and then leaves us to fend for ourselves with this ridiculously hard worksheet. Please help. 1. 2cscx =...
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    Conceptual questions on sound/waves

    Homework Statement 1. A child is swinging in simple harmonic motion. Where in his swing is the velocity the greatest? (Top, bottom, mid-way on the way up, or mid-way on the way down.) 2. A buoy in the ocean is bobbing up and down repeatedly. Explain why this is or isn't an example of simple...
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    A few easy conceptual questions

    Homework Statement Here are a couple of conceptual questions from my cumulative review. 1. Is energy released or absorbed when a gas changes to a liquid? 2. If a yo-yo is being whirled around by its string in a vertical circle, does the string apply an outward force or an inward force...
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    Excess Electron Question

    Homework Statement A typical lightning bolt has about 10.0 C of charge. How many excess electrons are in a typical lightning bolt? Homework Equations There's something in my notes that is confusing me, but I think it could be relevant. It says e = 1.6 x 10-19c The Attempt at a...
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    Conceptual Question About Heat

    Homework Statement Explain why a tile floor feels cold on your feet, but a carpeted floor in a room with the same temperature feels warm. Homework Equations N/A The Attempt at a Solution I think it's because the carpet is a better insulator and loses its energy much more slowly...
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    Specific Heat Capacity Question

    Homework Statement How much milk at 11 degrees Celcius was added to 0.16 kg of coffee at 91 degrees Celcius if the final temperature is 76.8 degrees Celcius? Homework Equations Well my teacher explained how to rearrange cm∆T = cm∆T to somehow come up with an equation to solve for the...
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    Specific Heat Capacity Problem

    Homework Statement How much ice was added to a 0.75 kg jug of lemonade at 15 degrees celcius if the final temperature of the jug is 8 degrees celcius? (Assume the lemonade has the specific heat capacity of water.) Homework Equations Q = cm∆T The Attempt at a Solution Well I think I...
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    Conservation of energy problem

    Homework Statement A 2.5 kg block of ice at a temperature of zero degrees celcius and an initial speed of 5.7 m/s slides across a level floor. If 3.3 x 105 J are required to melt 1 kg of ice, how much ice melts, assuming that the initial kinetic energy of the ice block is entirely converted to...
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    Circular Motion of an automobile

    Homework Statement This is just a conceptual question: Give an example of a situation in which an automobile driver can have a centripetal acceleration but no tangential acceleration. Homework Equations N/A The Attempt at a Solution I understand that centripetal acceleration...
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    Momentum and Collisions

    Homework Statement Ok, I have a couple problems that I'm having trouble with. Bear with me, my physics teacher can be a little creative...lol. 1. I am an expert swan diver. If I am jumping off a 3m diving board, what is the velocity with which I strike the water? If the water brings me to...
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    Impulse-Momentum Theorem and diving board

    Homework Statement An 82 kg man drops from rest on a diving board 3m above the surface of the water and comes to rest 0.55 s after reaching the water. What force does the water exert on him? Homework Equations F = mVf - mVi / t The Attempt at a Solution I have no idea where to...
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    Energy conservation used to predict speed?

    Homework Statement I don't know if anyone can help me with this without having done the lab, but I thought I'd give it a shot. Ok, so I did a lab in my physics class where we used little rollercoasters to find the PE and KE of a marble at various heights and speeds. Here is the question in my...
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    Log equation question

    Homework Statement Solve for x: 2log3x + log3(x-1) = log32 + log36x Homework Equations N/A The Attempt at a Solution Ok, so I tried to solve it and I came up with this and got stuck. log3(x3-x2) = log312x Even if I cancelled out the logs it would be x3-x2 = 12x and then how...
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    Elastic Potential Energy Physics Problem

    Homework Statement The staples inside a stapler are kept in place by a spring with a relaxed length of 0.115 m. If the spring constant is 51 N/m, how much elastic potential energy is stored in the spring when its length is 0.150 m? Ok, so: Relaxed length= 0.115 m k= 51 N/m x= .150-.115=...
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