The Capelli identity,the double commutant theorem,and multiplicity-free actions

Partially supported by NSF grant #DMS-8807336     

(GLn,GLm)-duality and symmetric plethysm

In [7] the author has given an exposition of the theory of invariants of binary forms in terms of a particular version of Classical Invariant Theory. Reflection shows that many aspects of the development apply also ton-ary forms. The purpose of this paper is to make explicit this more general application. The plethysms S’(S^p(ℂⁿ)) are computed quite explicitly forl = 2, 3 and 4. Partially supported by NSF Grant No. DMS 8506130.     

Preparation and stereochemistry of 3-phenacylidenephthalimidines

Yields of 3-phenacylidenephthalimidines are maximized and yields of phthalimide byproducts are minimized by use of acetic acid as the solvent in reactions of amines with 3-phenacylidenephthalides. The 3-phenacylidenephthalimidines are formed as E, Z mixtures, in which the E isomers predominate. A homonuclear NOE nmr experiment was employed to determined product stereochemistry.     

Implementation and evaluation of data compression of MR images

A full-frame bit-allocation technique of data compression has been implemented using the existing computer facilities of an MR imager. Images reconstructed from compressed data files have been compared with the original image and changes in noise and pixel value measured to evaluate any image degradation introduced by the compression process. A 256 x 256 x 8 bit brain image can be compressed in 20 seconds with a compression ratio of greater than 4:1 without significant loss of information.     

Diffraction of bending waves

This paper is a discussion of the theory of diffraction and scattering of bending waves by mass-impedance loadings of an infinite plane plate. Emphasis is placed on the case of heavy loadings, at which deflexions of the plate are precluded and the scattering is the strongest possible. Examples treated in detail include the diffraction grating, diffraction by a semi-infinite rib, and diffraction by a comb of semi-inifinite ribs.     

Gamma-ray spectra and level structure of Cr from thermal neutron capture in Cr

Gamma-ray measurements have been made of the ⁵⁴Cr(n, γ)⁵⁵ Cr reaction at the Livermore reactor. Spectra were taken with Ge(Li) Compton-suppression and pair-coincidence spectrometers. A total of 83 observed γ-rays are attributed to capture in ⁵⁴Cr, of which 26 are assigned to specific transitions among 10 inferred levels in ⁵⁵Cr. The neutron binding energy is determined to be 6246.3 ± 0.4 keV.     

Plastic Versus Glass Support for an Immunoassay on Metal-Coated Surfaces in Optically Dense Samples Utilizing Directional Surface Plasmon-Coupled Emission

We compared plastic (polycarbonate) and high-quality glass support materials for gold-coated slides, when performing a model immunoassay against rabbit IgG using fluorescently labeled (AlexaFluor-647) anti-rabbit IgG, and detecting surface plasmon-coupled emission (SPCE) signals. Both, glass and plastic slides were simultaneously coated with a 48-nm layer of gold and protected with a 10-nm layer of silica. The maximum SPCE signal of AlexaFluor-647 was only two- to three-fold smaller on plastic slides than on glass slides. A small difference in the SPCE angles on glass (θ _F = 55°) and plastic (θ _F = 52.5°) slides was observed and can be explained with a slightly smaller refractive index of the plastic. We have not found any difference in the angle distribution (sharpness of the fluorescence signal at optimal SPCE angle) for the plastic slide compared to the glass slide. The kinetics of binding was monitored on the plastic slide as well as on the glass slide. Optically dense samples, a 4% red blood cell suspension and a 15% hemoglobin solution, are causing a reduction in the immunoassay SPCE signal by approximately 15% and three times, respectively, and the percentage of the reduction is the same for plastic and for glass slides. We believe that plastic substrates can be readily used in any SPCE assay, with only marginally lower total signal compared to high-quality glass slides.     

Thermophile-specific proteins: the gene product of <Emphasis Type="Italic">aq_1292</Emphasis> from <Emphasis Type="Italic">Aquifex aeolicus</Emphasis> is an NTPase

Background  

To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618) which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs) and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed biochemically thus far, we characterized the gene product of aq_1292 which is THEP1 from the hyperthermophilic bacterium Aquifex aeolicus (aaTHEP1).