Stereoisomers of selenilimines: isolation and reactions of 9-phenylselenoxanthene-N-arylsulfonylselenilimines

The isolates cis- and trans-9phenylselenoxanthene-N-arylsulfonylselenilimines were not interconverted thermally. cis-Isomers were converted to trans-isomers by chloramine-T or -B in a fashion of S_N2 type substitution. cis-Isomers did not rearrange but trans-isomers rearranged thermally to 9-arylsulfonamido-9-phenylselenoxanthenes, whereas both isomers underwent the base-catalyzed intermolecular rearrangement.     

1-vinylbenzene 1,2- and 3,4-oxides

Synthesis of highly unstable vinyl-substituted benzene oxides has been established.     

Catalyzed cycloaddition reactions of α-silyloxy-α,β-unsaturated ketone and aldehyde

The reactions of α-silyloxy-ga,β-unsaturated ketone and aldehyde with diene afforded [4+2] and [4+3] cycloadducts respectively in the presence of a catalyst.     

Cyclic dithio-carbenium ion salts and their conversion to ketene dithioacetals

1,2-Ethanedithiol and 1,3-propanedithiol were treated with perchloric acid in acetic anhydride to give 2-methyl-1,3-dithiolan-2-yl and 2-methyl-1,3-dithian-2-yl perchlorates, respectively, which were converted to ketene dithioacetals by deprotonation with tertiary amines.     

Surface-enhanced Raman scattering from crystal violet adsorbed on a silver electrode

SERS from crystal violet (CV) on a Ag electrode was investigated under preresonance and resonance conditions. The excitation profile of the chemisorbed species is like that of dissolved molecules but intensities are ≈ 1000 times larger. The Raman enhancement is ≈ 10⁸ and exhibits a specific potential dependence even in the absence of adsorption-desorption process. At potentials where reduction of CV occurs leuco crystal violet was detected.     

BLUE and NEAR ULTRAVIOLET REVERSIBLE PHOTOREACTION IN THE INDUCTION OF FUNGAL CONIDIATION

Abstract— The effects of blue light and near UV light on the induction of conidiation in the fungus, Aliernuriu tomato, were investigated. Induction of conidiation was repeatedly controlled by alternating doses of near UV light and blue light. When the final light was near UV, conidiation was induced and conidia developed in the following darkness; when it was blue, the induction of conidiation was suppressed. When conidiation was induced by irradiation with a light mixed with near UV and blue, not only the time lag for inducing conidiation but also the amount of conidia formed were regulated by the fluence rates of both those lights.
Thus, 'mycochrome' is considered to function as a photoreceptor system in the induction of conidiation of this fungus.     

A counterexample to the bold conjecture

A pair of vertices (x,y) of a graph G is an o-critical pair if o(G + xy) > o(G), where G + xy denotes the graph obtained by adding the edge xy to G and o(H) is the clique number of H. The o-critical pairs are never edges in G. A maximal stable set S of G is called a forced color class of G if S meets every o-clique of G, and o-critical pairs within S form a connected graph. In 1993, G. Bacsó raised the following conjecture which implies the famous Strong Perfect Graph Conjecture: If G is a uniquely o-colorable perfect graph, then G has at least one forced color class. This conjecture is called the Bold Conjecture. Here we show a simple counterexample to it. © 1997 John Wiley & Sons, Inc. J Graph Theory 25: 165–168, 1997     

An ore-type condition for the existence ofk-factors in graphs

Letk be a positive integer, and letG be a graph of ordern withn 4k – 5,kn even and minimum degree at leastk. We prove that if the degree sum of each pair of nonadjacent vertices is at leastn, thenG has ak-factor.     

Upper and Lower Bounds on Maximum Nonlinearity of n-input m-output Boolean Function

The paper presents lower and upper bounds on the maximumnonlinearity for an n-input m-output Booleanfunction. We show a systematic construction method for a highlynonlinear Boolean function based on binary linear codes whichcontain the first order Reed-Muller code as a subcode. We alsopresent a method to prove the nonexistence of some nonlinearBoolean functions by using nonexistence results on binary linearcodes. Such construction and nonexistence results can be regardedas lower and upper bounds on the maximum nonlinearity. For somen and m, these bounds are tighter than theconventional bounds. The techniques employed here indicate astrong connection between binary linear codes and nonlinear n-input m-output Boolean functions.     

Influence of Zn Diffusion on Bandwidth and Extinction in MQW Electroabsorption Modulators Buried with Semi-Insulating InP

A comprehensive analysis of multi-quantum-well electroabsorption modulators buried with semi-insulating (SI)-InP is presented. We quantitatively demonstrate that suppression of Zn diffusion into the burying and optical core layers plays a key role in high-speed and high-extinction operation.