First synthesis of 10 alpha-(trifluoromethyl)deoxoartemisinin

[reaction: see text] A novel, nonacetal (trifluoromethyl)deoxoartemisinin was prepared with good stereoselectivity. This compound was obtained by debromination of the 10 alpha-CF3-10-bromodeoxoartemisinin in the presence of tributyltin hydride at reflux in toluene without alteration of the endoperoxide bridge. It presented a reasonable antimalarial activity.     

Paley–Wiener and Boas theorems for singular Sturm–Liouville integral transforms

This paper deals with a class of integral transforms arising from a singular Sturm–Liouville problem y″−q(x)y=−λy, x(a,b), in the limit-point case at one end or both ends of the interval (a,b). The paper completely solves the problem of characterization of the image of a function that has compact support (Paley–Wiener theorem) and also of a function that vanishes on some interval (Boas problem) under this class of transforms. The characterizations are obtained with no restriction on q(x) other than being locally integrable.     

Magnetic and transport properties of Cu2MnAl Heusler alloy prepared by rapidly quenched method

The Cu₂MnAl alloy was prepared by rapidly quenched (suction-casting and melt-spinning) methods with various thicknesses of 20, 40 and 1000 μm. The X-ray diffraction (XRD) patterns of the fabricated samples show a single phase of Cu₂MnAl. All the samples reveal soft magnetic behavior with coercivity below 1.6 kA/m and Curie temperature of about 600 K. Resistance of the alloy behaves as a linear function of applied magnetic field. Magnetoresistance (MR) ratio depends on the thickness of the samples and achieves ∼0.8% at the field of 240 kA/m for the sample with thickness of 20 μm. The variation of the properties of the alloy can be interpreted by the difference of energy band structure caused by defects in the alloy.     

A near-optimal manhattan channel router for a class of nets with the shift-right-one pattern

The Manhattan channel routing problem of providing a one-to-one rectilinear wire connection (horizontal segments on one layer, while vertical segments are on the other) between two sets of terminals which lie on two horizontal lines, with the smallest width, is NP-hard. In this paper, it is studied for m consecutive shift-right-one nets, and a near-optimal router which produces a layout with width at most 2 more than the theoretical lower bound given in [1] is presented.     

Some aspects of the quark parton model

A modified Kuti-Weisskopf model which satisfies the Feynman threshold constraints is considered further. Detailed predictions for the sum of neutrino and anti-neutrino differential cross sections on nucleon (which can be readily compared with forthcoming NAL data), the shapes of the structure functions $\text{?}{}_2{}^{\mathrm{\nu p,\nu n}}$ and the ratio $\text{?}{}_2{}^{\mathrm{\nu p}}\text{/?}{}_2{}^{\mathrm{\nu n}}$, and spin-dependence of inelastic electron-nucleon scattering versus scaling variable x are delineated. We also compare in some detail the general features of our model with the “model independent” approach of Feynman for quark parton theory.     

Factorizing dual amplitude with mandelstam analycity

We present a N-point function with following properties: a) it factorizes, b) it has Regge asymptotic behaviour with non-linear trajectories, c) it has Mandelstam analyticity, d) it reduces to the Veneziano N-point function in the narrow resonance limit.     

A Liouville Theorem for Matrix-Valued Harmonic Functions on Nilpotent Groups

Let be a non-degenerate positive M_n-valued measure on a locallycompact group G with |||| = 1. An M_n-valued Borel function fon G is called -harmonic if for all x G. Given such a function f which is bounded and leftuniformly continuous on G, it is shown that every central elementin G is a period of f. Further, it is shown that f is constantif G is nilpotent or central. 2000 Mathematics Subject Classification31C05, 43A05, 45E10, 46G10.     

On local cohomology and Hilbert function of powers of ideals

Let I be a homogeneous ideal in a polynomial ring R=K[x₁,,x_m], where K is an infinite field. In this article we investigate the asymptotic behaviour of the a_i-invariants and the regularity index of the ring R/Iⁿ when n»0.Both authors were supported by the Academy of Finland, Project 48556. The first named author was also supported in part by the National Basic Research Program (Vietnam)Mathematics Subject Classification (2000):13D40, 13D45     

A novel ent-kaurane diterpenoid from the Croton tonkinensis GAGNEP

A novel ent-kaurane diterpenoid, ent-1alpha-acetoxy-7beta,14alpha-dihydroxy-kaur-16-en-15-on has been isolated from leaves of Croton tonkinensis GAGNEP. Its structure was determined by a combination of spectroscopy, X-ray crystallographic analysis and the chemical reaction acetylation.     

New colorimetric and fluorometric chemosensor based on a cationic polythiophene derivative for iodide-specific detection

Electrostatic interactions between anions and a new water-soluble, cationic, affinitychromic poly(3-alkoxy-4-methylthiophene) derivative provide a new tool for a selective optical detection method (colorimetric or fluorometric) for iodide ions.