Artificial nucleosides possessing metal binding sites at the 3'- and 5'-positions of the deoxyribose moieties

This paper describes a convenient synthetic procedure for nucleoside mimics, 1-6, in which the 3',5'-hydroxy groups of natural 2'-deoxythymidine or 2'-deoxyadenosine are replaced by thiol, amine, or alkylthiol groups. Such nucleosides would be built up into a single DNA strand with cooperative participation of metal coordination, where internucleoside linkages are replaced by metal complexation motifs. The X-ray crystal structure and complexation behaviors of 3',5'-dithiothymidine, 1, with Au(I) are also reported.     

Ten new Lycopodium alkaloids having the lycopodane skeleton isolated from Lycopodium serratum Thunb

Ten new alkaloids, lycoposerramines-F (1), -G (2), -H (3), -I (4), -J (5), -K (6), -L (7), -M (8), -N (9), and -O (10), having lycopodine-related structures, were isolated from the club moss Lycopodium serratum THUNB. and their structures were elucidated on the basis of spectroscopic analysis and/or chemical transformation.     

Reversible switching of high-speed air-liquid two-phase flows using electrowetting-assisted flow-pattern change

This work is the first demonstration of electrical modulation of surface energy to reversibly switch dynamic high-speed gas-liquid two-phase microfluidic flow patterns. Manipulation of dynamic two-phase systems with continuous high-speed flows is complex and interesting due to the multiple types of forces that need to be considered. Here, distinct stable flow patterns are formed through a multipronged approach: both surface tension forces generated by surface chemistry modulation as well as viscous and inertial forces produced by fluid flows are employed. The novel fluidic actuation mechanism provides insights into better understanding microscale two-phase flow dynamics and offers new opportunities for the development of two-phase biochemical microsystems that are mechanically simple and operational at high speeds.     

Aging of the zero-field-cooled magnetization in Ising spin glasses: experiment and numerical simulation

Growth of the zero-field-cooled magnetization (ZFCM) under continuous heating with and without an intermittent stop(s) is studied on Ising spin glasses both experimentally and numerically. Despite the large difference between time scales of the experiment and the simulation, the ZFCM behavior observed in the two systems can be quantitatively interpreted by means of a common set of the scaling expressions based on the droplet picture. The results strongly suggest that the spin-glass coherence length reached by the laboratory time scales is about a hundred lattice spacings or less. Within this length scale no signature of the chaos effect (rejuvenation) has been found in the ZFCM measured.     

Observation of the "self-healing" of an error field island in the large helical device

It was observed that the vacuum magnetic island produced by an external error magnetic field in the large helical device shrank in the presence of plasma. This was evidenced by the disappearance of flat regions in the electron temperature profile obtained by Thomson scattering. This island behavior depended on the magnetic configuration in which the plasmas were produced.     

Extensions between finite-dimensional simple modules over a generalized current Lie algebra

We calculate the first extension groups for finite-dimensional simple modules over an arbitrary generalized current Lie algebra, which includes the case of loop Lie algebras and their multivariable analogs.     

Permeability enhancement of stratified metal dielectric metamaterial in optical regime

Magnetic response of stratified metal dielectric metamaterial (SMDM) is demonstrated numerically and experimentally. One unit cell of SMDM has a sandwich unit cell consisting of alumina (60 nm)/silver (30 nm)/alumina (60 nm). A Mach–Zehnder interferometer is used to obtain phase information of transmittance and reflectance from which effective permeability is determined. The maximum permeability amounts to 20 and 17 for calculation and experiment, respectively. This huge resonance occurs when the magnetic field is concentrated at the metal layer, while the electric field has a node at the center.     

Metallocene bis(perfluoroalkanesulfonate)s as air-stable cationic Lewis acids

Zirconocene and titanocene bis(perfluorooctanesulfonate)s were synthesized. In contrast to the corresponding triflates and perchlorates, these compounds are air- and water-stable. They were proved to be ionic on the basis of conductivity measurements and X-ray analysis, allowing these complexes to be stored for months. The strong Lewis acidity of these cationic metallocene species, which was proved by ESR study, enabled catalytic glycosylation.     

On the radical of a monomial ideal

Algebraic and combinatorial properties of a monomial ideal and its radical are compared. Received: 9 October 2004