996 research outputs found
Diamond Integrated Optomechanical Circuits
Diamond offers unique material advantages for the realization of micro- and
nanomechanical resonators due to its high Young's modulus, compatibility with
harsh environments and superior thermal properties. At the same time, the wide
electronic bandgap of 5.45eV makes diamond a suitable material for integrated
optics because of broadband transparency and the absence of free-carrier
absorption commonly encountered in silicon photonics. Here we take advantage of
both to engineer full-scale optomechanical circuits in diamond thin films. We
show that polycrystalline diamond films fabricated by chemical vapour
deposition provide a convenient waferscale substrate for the realization of
high quality nanophotonic devices. Using free-standing nanomechanical
resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate
efficient optomechanical transduction via gradient optical forces. Fabricated
diamond resonators reproducibly show high mechanical quality factors up to
11,200. Our low cost, wideband, carrier-free photonic circuits hold promise for
all-optical sensing and optomechanical signal processing at ultra-high
frequencies
Expression of the DNA mismatch repair proteins hMLH1 and hPMS2 in normal human tissues.
hMLH1 and hPMS2 are part of the DNA mismatch repair complex. Mutations in these genes have been linked to hereditary non-polyposis colon cancer; they also occur in a variety of sporadic cancers. Western blot analysis and immunohistochemistry demonstrated that hMLH1 and hPMS2 are widely expressed nuclear proteins with a distribution pattern very similar to that previously described for hMSH2. These observations showing similar localization of hMLH1 and hPMS2 with hMSH2 are consistent with the biochemical function of these proteins in DNA mismatch repair
Serodiagnosis of infectious mononucleosis by using recombinant Epstein-Barr virus antigens and enzyme-linked immunosorbent assay technology
Four recombinant, diagnostically useful Epstein-Barr virus (EBV) proteins representative of the viral capsid antigen (p150), diffuse early antigen (p54), the major DNA-binding protein (p138), and the EBV nuclear antigen (p72) (W. Hinderer, H. Nebel-Schickel, H.H. Sonneborn, M. Motz, R. KĂĽhbeck, and H. Wolf, J. Exp. Clin. Cancer Res. 7[Suppl.]:132, 1988) were used to set up individual enzyme-linked immunosorbent assays (ELISAs) for the qualitative and quantitative detection of immunoglobulin M (IgM) and IgG antibodies. In direct comparison with results obtained by standard immunofluorescence or immunoperoxidase assays, it was then shown that the recombinant EBV ELISAs provide the means for specific and sensitive serodiagnosis of infectious mononucleosis (IM) caused by EBV. The most useful markers in sera from such patients proved to be IgM antibodies against p54, p138, and p150. Additional positive markers for recent or ongoing IM apparently were IgG antibodies against p54 and p138. In contrast, anti-p72 IgG had a high preference for sera from healthy blood donors and, therefore, can be considered indicative of past exposure to the virus. Altogether, the individual ELISAs proved to be as specific and at least as sensitive for the diagnosis of IM as the currently available standard techniques are. Moreover, our findings suggest that, by combining individual test antigens, a workable ELISA system consisting of three assays (IgM against p54, p138, and p150; IgG against p54 and p138; and IgG against p72) can be established for the standardized rapid diagnosis of acute EBV infections
A Generative-Discriminative Basis Learning Framework to Predict Clinical Severity from Resting State Functional MRI Data
We propose a matrix factorization technique that decomposes the resting state
fMRI (rs-fMRI) correlation matrices for a patient population into a sparse set
of representative subnetworks, as modeled by rank one outer products. The
subnetworks are combined using patient specific non-negative coefficients;
these coefficients are also used to model, and subsequently predict the
clinical severity of a given patient via a linear regression. Our
generative-discriminative framework is able to exploit the structure of rs-fMRI
correlation matrices to capture group level effects, while simultaneously
accounting for patient variability. We employ ten fold cross validation to
demonstrate the predictive power of our model on a cohort of fifty eight
patients diagnosed with Autism Spectrum Disorder. Our method outperforms
classical semi-supervised frameworks, which perform dimensionality reduction on
the correlation features followed by non-linear regression to predict the
clinical scores
Diamond electro-optomechanical resonators integrated in nanophotonic circuits
Diamond integrated photonic devices are promising candidates for emerging
applications in nanophotonics and quantum optics. Here we demonstrate active
modulation of diamond nanophotonic circuits by exploiting mechanical degrees of
freedom in free-standing diamond electro-optomechanical resonators. We obtain
high quality factors up to 9600, allowing us to read out the driven
nanomechanical response with integrated optical interferometers with high
sensitivity. We are able to excite higher order mechanical modes up to 115 MHz
and observe the nanomechanical response also under ambient conditions.Comment: 15 pages, 4 figure
Existence of Monetary Steady States in a Matching Model: Indivisible Money
Existence of a monetary steady state is established for a random matching model with divisible goods, indivisible money, and take-it-or-leave-it offers by consumers. There is no restriction on individual money holdings. The background environment is that in papers by Shi and by Trejos and Wright. The monetary steady state shown to exist has nice properties: the value function, defined on money holdings, is increasing and strictly concave, and the measure over money holdings has full support.
Inertial electrostatic confinement as a power source for electric propulsion
The potential use of an INERTIAL ELECTROSTATIC CONFINEMENT (IEC) power source for space propulsion has previously been suggested by the authors and others. In the past, these discussions have generally followed the charged-particle electric-discharge engine (QED) concept proposed by Bussard, in which the IEC is used to generate an electron beam which vaporizes liquid hydrogen for use as a propellant. However, an alternate approach is considered, using the IEC to drive a 'conventional' electric thruster unit. This has the advantage of building on the rapidly developing technology for such thrusters, which operate at higher specific impulse. Key issues related to this approach include the continued successful development of the physics and engineering of the IEC unit, as well as the development of efficient step-down dc voltage transformers. The IEC operates by radial injection of energetic ions into a spherical vessel. A very high ion density is created in a small core region at the center of the vessel, resulting in extremely high fusion power density in the core. Experiments at the U. of Illinois in small IEC devices (is less than 60 cm. dia.) demonstrated much of the basic physics underlying this concept, e.g. producing 10(exp 6) D-D neutrons/sec steady-state with deuterium gas flow injection. The ultimate goal is to increase the power densities by several orders of magnitude and to convert to D-He-3 injection. If successful, such an experiment would represent a milestone proof-of-principle device for eventual space power use. Further discussion of IEC physics and status are presented with a description of the overall propulsion system and estimated performance
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