11,193 research outputs found
The Knowledge Filter and Economic Growth: The Role of Scientist Entrepreneurship
Assesses the prevalence of and trends in the commercialization of research by university scientists funded by the National Cancer Institute. Analyzes levels of entrepreneurship in patenting choices and the role of university technology transfer offices
The Knowledge Filter and Economic Growth: The Role of Scientist Entrepreneurship
Assesses the prevalence of and trends in the commercialization of research by university scientists funded by the National Cancer Institute. Analyzes levels of entrepreneurship in patenting choices and the role of university technology transfer offices
Linear relaxation to planar Travelling Waves in Inertial Confinement Fusion
We study linear stability of planar travelling waves for a scalar
reaction-diffusion equation with non-linear anisotropic diffusion. The
mathematical model is derived from the full thermo-hydrodynamical model
describing the process of Inertial Confinement Fusion. We show that solutions
of the Cauchy problem with physically relevant initial data become planar
exponentially fast with rate s(\eps',k)>0, where
\eps'=\frac{T_{min}}{T_{max}}\ll 1 is a small temperature ratio and
the transversal wrinkling wavenumber of perturbations. We rigorously recover in
some particular limit (\eps',k)\rightarrow (0,+\infty) a dispersion relation
s(\eps',k)\sim \gamma_0 k^{\alpha} previously computed heuristically and
numerically in some physical models of Inertial Confinement Fusion
Sequence-Specific Recognition and Cooperative Dimerization of N-Terminal Aromatic Peptides in Aqueous Solution by a Synthetic Host
This article describes the selective recognition and noncovalent dimerization of N-terminal aromatic peptides in aqueous solution by the synthetic host compound, cucurbit[8]uril (Q8). Q8 is known to bind two aromatic guests simultaneously and, in the presence of methyl viologen, to recognize N-terminal tryptophan over internal and C-terminal sequence isomers. Here, the binding of Q8 to aromatic peptides in the absence of methyl viologen was studied by isothermal titration calorimetry (ITC), 1H NMR spectroscopy, and X-ray crystallography. The peptides studied were of sequence X-Gly-Gly, Gly-X-Gly, and Gly-Gly-X (X = Trp, Phe, Tyr, and His). Q8 selectively binds and dimerizes Trp-Gly-Gly (1) and Phe-Gly-Gly (4) with high affinity (ternary K = 109−1011 M-2); binding constants for the other 10 peptides were too small to be measured by ITC. Both peptides bound in a stepwise manner, and peptide 4 bound with positive cooperativity. Crystal structures of Q8·1 and Q8·42 reveal the basis for selective recognition as simultaneous inclusion of the hydrophobic aromatic side chain into the cavity of Q8 and chelation of the proximal N-terminal ammonium group by carbonyl groups of Q8. The peptide sequence selectivity and positively cooperative dimerization reported here are, to the best of our knowledge, unprecedented for synthetic hosts in aqueous solution. Specific peptide recognition and dimerization by synthetic hosts such as Q8 should be important in the study of dimer-mediated biochemical processes and for the separation of peptides and proteins
Solitary vortex couples in viscoelastic Couette flow
We report experimental observation of a localized structure, which is of a
new type for dissipative systems. It appears as a solitary vortex couple
("diwhirl") in Couette flow with highly elastic polymer solutions. A unique
property of the diwhirls is that they are stationary, in contrast to the usual
localized wave structures in both Hamiltonian and dissipative systems which are
stabilized by wave dispersion. It is also a new object in fluid dynamics - a
couple of vortices that build a single entity somewhat similar to a magnetic
dipole. The diwhirls arise as a result of a purely elastic instability through
a hysteretic transition at negligible Reynolds numbers. It is suggested that
the vortex flow is driven by the same forces that cause the Weissenberg effect.
The diwhirls have a striking asymmetry between the inflow and outflow, which is
also an essential feature of the suggested elastic instability mechanism.Comment: 9 pages (LaTeX), 5 Postscript figures, submitte
Crystallization and preliminary X-ray crystallographic analysis of yeast NAD+-specific isocitrate dehydrogenase. Corrigendum
A corrigendum to the article by Hu et al. (2005), Acta Cryst. F61, 486–488
Comparison of two capacities in â„‚ n
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46271/1/209_2005_Article_BF01174894.pd
The formation of helium lines in the spectrum of COM J1740-5340
The He I 5876A absorption line recently discovered in the spectrum of the
companion to the millisecond pulsar PSR J1740-5340 is tentatively attributed to
electron impact excitations due to the irradiation of its atmosphere by
gamma-rays emitted by the pulsar's magnetosphere. Numerical calculations,
similar to those carried out previously for Type Ib SNe, indicate that a pulsar
beam with photon energies ~ 1 MeV gives rise to a 5876A line of the observed
strength if the beam's spin-down conversion efficiency approaches 1%. However,
a significant difficulty for the proposed mechanism is the strength of the
singlet line at 6678A. Compared to the corresponding triplets, singlet lines
are weak because of the loss of excitation when photons emitted in decays to
the ground state ionize hydrogen atoms, an effect absent in the hydrogen-free
atmospheres of Type Ib SNe.Comment: Accepted for publication in A&
New Combinations: Changing Technologies and Infrastructures and the Business Organizations That Will Deal with Them.
This tale is somewhat unique. It is probably one of the few panels, or the only panel in which there is a certain level of agreement. In fact, every one in this room probably has the basic agreement with this panel, that changes in regulation and changes in policy that we are struggling with are driven by changes in technology. This panel has been put together to look at changes in technology. It has three overall goals. The first is, as you heard one of the panels this morning talk about, to talk about technology itself to try to gain some type of understanding. As regulators or practitioners of law in the area, it is hard to be effective without some type of understanding of just what the technology is that we are supposed to be regulating or trying to give people advice concerning. The second area that this panel will hopefully inform us on is how technology continues to change. Many times we look back and see how technological changes have occurred, and how they have forced us to change. However, there is little consideration for the fact that these technologies continue to change and there will be other challenges or maybe even solutions to current problems that will result from that change in technology. And the final area we hope to provide information on is, as technology changes and as it causes regulators to address new issues, how the utilities, are themselves very different, and have been changed and shaped by this changing technology. This group, I think, can demonstrate very well how the conversion of the different technologies have shaped most of the companies and people who are on the panel
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