2,405 research outputs found
Computer program conducts facilities utilization and occupancy survey
Computer program identifies the uses of all facilities and provides information on the net area in each room as well as the number and classification of people occupying them. The system also provides a means to indicate unsatisfactory work areas and may be able to be updated each month
The Human Cytomegalovirus Fc Receptor gp68 Binds the Fc CH2-CH3 Interface of Immunoglobulin G
Recognition of immunoglobulin G (IgG) by surface receptors for the Fc domain of immunoglobulin G (Fc{gamma}), Fc{gamma}Rs, can trigger both humoral and cellular immune responses. Two human cytomegalovirus (HCMV)-encoded type I transmembrane receptors with Fc{gamma}-binding properties (vFc{gamma}Rs), gp34 and gp68, have been identified on the surface of HCMV-infected cells and are assumed to confer protection against IgG-mediated immunity. Here we show that Fc{gamma} recognition by both vFc{gamma}Rs occurs independently of N-linked glycosylation of Fc{gamma}, in contrast with the properties of host Fc{gamma}Rs. To gain further insight into the interaction with Fc{gamma}, truncation mutants of the vFc{gamma}R gp68 ectodomain were probed for Fc{gamma} binding, resulting in localization of the Fc{gamma} binding site on gp68 to residues 71 to 289, a region including an immunoglobulin-like domain. Gel filtration and biosensor binding experiments revealed that, unlike host Fc{gamma}Rs but similar to the herpes simplex virus type 1 (HSV-1) Fc receptor gE-gI, gp68 binds to the CH2-CH3 interdomain interface of the Fc{gamma} dimer with a nanomolar affinity and a 2:1 stoichiometry. Unlike gE-gI, which binds Fc{gamma} at the slightly basic pH of the extracellular milieu but not at the acidic pH of endosomes, the gp68/Fc{gamma} complex is stable at pH values from 5.6 to pH 8.1. These data indicate that the mechanistic details of Fc binding by HCMV gp68 differ from those of host Fc{gamma}Rs and from that of HSV-1 gE-gI, suggesting distinct functional and recognition properties
Spin susceptibility of the superfluid He-B in aerogel
The temperature dependence of paramagnetic susceptibility of the superfluid
^{3}He-B in aerogel is found. Calculations have been performed for an arbitrary
phase shift of s-wave scattering in the framework of BCS weak coupling theory
and the simplest model of aerogel as an aggregate of homogeneously distributed
ordinary impurities. Both limiting cases of the Born and unitary scattering can
be easily obtained from the general result. The existence of gapless
superfluidity starting at the critical impurity concentration depending on the
value of the scattering phase has been demonstrated. While larger than in the
bulk liquid the calculated susceptibility of the B-phase in aerogel proves to
be conspicuously smaller than that determined experimentally in the high
pressure region.Comment: 10 pages, 4 figures, REVTe
Universal Behaviour of the Superfluid Fraction and Tc of He-3 in 99.5% Open Aerogel
We have investigated the superfluid transition of He-3 in a 99.5% porosity
silica aerogel. This very dilute sample shows behaviour intermediary between
bulk He-3 and He-3 confined to the denser aerogels previously studied. We
present data on both the superfluid transition temperature and the superfluid
density and compare our results with previous measurements. Finally, we show
that the suppression of the superfluid transition temperature and suppression
of the superfluid density of He-3 in aerogel follow a universal relation for a
range of aerogel samples.Comment: 4 pages, 5 figures; 1 new figure, minor change
Model of Inhomogeneous Impurity Distribution in Fermi Superfluids
The standard treatment of impurities in metals assumes a homogeneous
distribution of impurities. In this paper we study distributions that are
inhomogeneous. We discuss in detail the "isotropic inhomogeneous scattering
model" which takes into account the spatially varying scattering on the scale
of the superfluid coherence length. On a large scale the model reduces to a
homogeneous medium with renormalized parameter values. We apply the model to
superfluid 3He, where porous aerogel acts as the impurity. We calculate the
transition temperature Tc, the order parameter, and the superfluid density.
Both A- and B-like phases are considered. Two different types of behavior are
identified for the temperature dependence of the order parameter. We compare
the calculations with experiments on 3He in aerogel. We find that most of the
differences between experiments and the homogeneous theory can be explained by
the inhomogeneous model. All our calculations are based on the quasiclassical
theory of Fermi liquids. The parameters of this theory for superfluid 3He in
aerogel are discussed.Comment: 14 pages, 9 figures, minor change
Mid-IR Spectroscopy of the Jovian Stratosphere perturbed by comet P/Shoemaker-Levy 9 Impact
The objective was to obtain spectra from 5 to 14 micron before, during, and after the impacts. We were awarded 2 flights of the KAO which was based in Melbourne, Australia for the events. Impacts R and W were covered, and the observations were completely successful. A paper reporting the observation of water vapor is in press, and other work is in progress as limited funding permits. The text of this report is adapted from that of the Icarus paper
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