The He(I) photoelectron spectroscopy of heavy group IV—VI diatomics

The He(I) photoelectron spectra of the Group IV—VI diatomics GeO, GeS, GeSe, GeTe, SnS, SnSe, and SnTe are presented. The outermost valence structure of these molecules is similar to that observed in the lighter series CO, CS, etc. of this valence isoelectronic group; in each case a relatively sharp peak is assigned to ionization from the nominally non-bonding 3σ orbital and a broader band to ionization from the bonding 1π orbital. At higher binding energies the spectra exhibit several peaks where only a single peak is expected, from the (2σ)^?1 hole state. This structure is assigned to correlation peaks resulting from configuration interaction among hole states of ²Σ⁺ (Ω = $\text{1}\text{2}$) symmetry. Semi-empirical CNDO—MO calculations have been performed for these molecules, and the results are used to interpret the observed trends. In addition, a simple molecular orbital model is employed to estimate the importance of spin—orbit coupling in the valence electronic structure of the heavy IV—VI ions.     

Positive scalar curvature for manifolds with elementary abelian fundamental group

The statement often called the Gromov-Lawson-Rosenberg Conjecture asserts that a manifold with finite fundamental group should admit a metric of positive scalar curvature except when the -valued index of some Dirac operator with coefficients in a flat bundle is non-zero. We prove spin and oriented non-spin versions of this statement for manifolds (of dimension ) with elementary abelian fundamental groups , except for ``toral' classes, and thus our results are automatically applicable once the dimension of the manifold exceeds the rank of . The proofs involve the detailed structure of , as computed by Johnson and Wilson.

     

SEMICONDUCTION AND PHOTOCONDUCTION ACTIVATION ENERGIES OF THE RETINALS

Abstract -The semiconduction and photoconduction currents through 1-ml thick sandwich cells of all-trans-, 13- cis- , 11- cis -retinal-, and 13- cis -retinal-m-nitroaniline-hydrogen chloride were measured as a function of the temperature in both the crystalline and melted states. From the slopes of graphs of the log of the current against 1000/TGK, the activation energies for semiconduction and photoconduction were calculated using the conductivity equations for the band model. The results of the average semiconduction activation energy measurements fell into two categories: The first group has activation energies between 1.9 and 2.4 eV and includes crystalline all- trans- , 13- cis -,9 cis -retinal, and both crystalline and melted 13- cis -retinal- m -nitroanaline hydrogen chloride; the second group has activation energies between 3.1 and 3.6 eV and includes crystalline 11- cis -retinal samples shorted. The average photoconduction activation energy for crysalline 13- cis - and 11- cis -retinal, being 0.25 and 0.24 eV respectively, were essentially identical within experimental error, whereas the same parameter for 13- cis -retinal- m -nitroaniline hydrogen chloride was considerably lower at 0.15 eV. All- trans -retinal was not measurably photoconductive and 9- cis -retinal was only slightly photoconductive.     

Application of pseudo-Boolean programming to the theory of graphs

The method of pseudo-Boolean programming (given in [5], [7] and briefly described in § 2 of this paper) is used for the systematic determination of the chromatic number, of the number of internal stability, of the number of external stability and of the kernels of a finite graph.     

Precision controlled trigonometric algorithms

This paper presents a new method to implement Taylor series in floating point arithmetic to generate trigonometric functions. With this method the number of terms that need to be computed is determined a priori from the exponent in the floating point representation of the argument, thereby minimizing execution time while maintaining a specified level of significance.     

Polynomial indexing of integer lattice-points I. General concepts and quadratic polynomials

Denoting the nonnegative integers by N and the signed integers by Z, we let S be a subset of Z^m for m = 1, 2,… and f be a mapping from S into N. We call f a storing function on S if it is injective into N, and a packing function on S if it is bijective onto N. Motivation for these concepts includes extendible storage schemes for multidimensional arrays, pairing functions from recursive function theory, and, historically earliest, diagonal enumeration of Cartesian products. Indeed, Cantor's 1878 denumerability proof for the product N² exhibits the equivalent packing functions $\text{f}{}_{\mathrm{<mtext>Cantor</mtext>}}\text{(x, y) = {}\text{either}\text{x}\text{or}\text{y} +}\text{(x + y)(x + y + 1)}\text{2}$ on the domain N², and a 1923 Fueter-Pólya result, in our terminology, shows f_Cantor the only quadratic packing function on N². This paper extends the preceding result. For any real-valued function f on S we define a density $\text{S ÷ f =}\text{lim}{}_{\mathrm{n\to \infty }}\text{(}\text{1}\text{n}\text{)\#{S ? f}{}^{\mathrm{?1}}\text{([?n, +n])}}$, and for any packing function f on S we observe the fact S ÷ f = 1. Using properties of this density, and invoking Davenport's lemma from geometric number theory, we find all polynomial storing functions with unit density on N, and exclude any polynomials with these properties on Z, then find all quadratic storing functions with unit density on N², and exclude any quadratics with these properties on Z × N, Z². The admissible quadratics on N² are all nonnegative translates of f_Cantor. An immediate sequel to this paper excludes some higher-degree polynomials on subsets of Z².     

Affinity capillary electrophoresis applied to the studies of interactions of a member of heat shock protein family with an immunosuppressant

The bioaffinity of receptor-ligand interactions is investigated by determining the binding constant (association constant or dissociation constant) of the resulting complex utilizing affinity capillary electrophoresis (ACE). The ACE binding assay was established with a potent immunosuppressant, deoxyspergualin (DSG), that binds specifically to Hsc70, a constitutive or cognate member of heat shock protein 70 (Hsp70) family. Quantitative determination of binding constants under different running buffer systems provide comparative results. The association constants for the interaction between Hsc70 protein and DSG were found to be 5.7·10⁴ M⁻¹ in a buffer with pH 6.95 and 6.3·10⁴ M⁻¹ in a buffer with pH 5.30 (or corresponding dissociation constants, 18 and 16 μM, respectively) based on Scatchard analyses. Binding of DSG to a synthetic peptide, SINPDEAVAYGAAV-QAAILSGDK, one of the DSG-binding fragments found from tryptic digest of Hsc70 protein, provides further detailed information for the understanding of Hsc70 binding domain. The applicability of using coated capillaries was also evaluated for probing Hsc70-DSG interaction.