3—THE FINITE-DEFORMATION THEORY OF PLAIN-WEAVE FABRICS PART I: THE BIAXIAL-DEFORMATION THEORY

Theories of the biaxial tensile properties, the uniaxial tensile properties, and the shear-deformation properties of plain-weave fabrics are presented in a general form, a simplified stereo-model of the structure of plain-weave fabrics being used throughout these theories.

In the first part of this series, the biaxial tensile-deformation theory is presented with the aid of the model, and the forces required to stretch the fabric along the warp and weft directions at the same time are theoretically calculated from the properties of yarns and from the structure of the fabrics. In this biaxial theory, both warp and weft yarns are assumed to be perfectly flexible, and the forces caused by yarn-bending are ignored. The compressibility of the yarn under the action of a lateral compressive force is also introduced into the theory, and it is shown that the compressive properties of yarns have a great influence on the tensile properties of the fabrics.     

Dependence of ion selectivity on ordered orientation of neutral carriers in ion-sensing membranes based on thermotropic liquid crystals

Thermotropic liquid-crystalline compounds were applied as membrane materials (membrane solvent and neutral carrier) for neutral carrier-type ion sensors to investigate how the ordered arrangement of neutral carriers affects the property of the resulting ion sensors. Nematic, smectic, and cholesteric liquid-crystalline compounds were used as the membrane solvents and crown ether derivatives with a molecular structure similar to the liquid-crystalline solvent as the K+ neutral carriers. Polarized IR spectroscopy and X-ray diffraction experiments confirmed that the highly ordered arrangement of membrane components was retained in the liquid-crystal-based ion-sensing membranes containing a neutral carrier and a lipophilic salt. The ordered arrangement of neutral carriers in the liquid-crystalline membranes enhanced the ion selectivity significantly, probably due to the efficient cooperation of two adjacent crown ether moieties in the highly ordered and aggregated state.     

Deletion and insertion of a 192-residue peptide in the active-site domain of glycosyl hydrolase family-2 beta-galactosidases

The monomeric multimetal-binding beta-galactosidase of Saccharopolyspora rectivirgula (srbg), a glycosyl hydrolase family-2 enzyme, has a unique sequence consisting of 192 amino acid residues with no similarity to known proteins. This 192-residue sequence (termed the "iota [iota] sequence") appears to be inserted into a sequence homologous to the active-site domain of the Escherichia coli lacZ enzyme (lacZbg). To assess the effects of the t sequence at specific sites of beta-galactosidase on the catalytic functioning and molecular properties of beta-galactosidase, deletion or insertion mutants of beta-galactosidases were constructed, expressed in LacZ- E. coli strains, and characterized: srbgdelta in which the iota sequence was deleted from srbg, and lacZbgI, in which the 192-residue iota sequence was inserted into the corresponding position (between Asp591 and Phe592) in the active-site domain of lacZbg. srbgdelta was a catalytically inactive, dimeric protein which retained multimetal-binding characteristics, suggesting that the iota sequence is very important for maintaining the structure necessary for the catalytic functioning and the monomeric structure of srbg but is not responsible for the unique metal ion requirements of srbg. On the other hand, lacZbgI existed as a mixture of a monomer, a tetramer, and higher multimers. The monomeric species was inactive, whereas the tetramer and other multimers were catalytically active (V(max )K(m) value, 25% of that of lacZbg) and highly specific for beta-D-galactoside. The tetrameric lacZbgI was activated by Mg2+ and Mn2+ with lowered metal affinities, and the stoichiometry of metal binding was unchanged from that of lacZbg. These results, along with the published stereo structure of lacZbg, suggest that, in lacZbgI, the inserted 192-residue iota peptide could fold independently of the lacZbg domains into a "sub-domain," lying distant from the active site and subunit interfaces.     

Novel sugar phosphotransferase system applicable to the efficient labeling of the compounds synthesized via the non-mevalonate pathway in Escherichia coli

It is known that 1-deoxy-D-xylulose taken up by Escherichia coli is used as the precursor of the compounds synthesized via the non-mevalonate pathway, such as isoprenoids, probably after conversion into 1-deoxy-D-xylulose 5-phosphate. In this report, we show that a novel phospho(enol) pyruvate-dependent phosphotransferase system catalyzes the uptake and phosphorylation of 1-deoxy-D-xylulose.     

Parallel implementation of the projector augmented plane wave method for charged systems

A parallel implementation of the projector augmented plane wave (PAW) method with the applications to several transition metal complexes is presented. A unique aspect of our PAW code is that it can treat both charged and neutral cluster systems. We discuss how this is achieved via accurate numerical treatment of the Coulomb Green's function with free space boundary conditions. The strategy for parallelizing the PAW code is based on distributing the plane wave basis across processors. This is a versatile approach and is implemented using a parallel three-dimensional Fast Fourier Transformation (FFT). We report parallel performance analysis of our program and of the three-dimensional FFT's and discuss large-scale parallelization issues of the PAW code. Using a series of transition metal monoxides and dioxides, as well as two iron aqueous complexes, it is shown that a free space PAW code can give structural parameters and energies in good accord with Gaussian based methods.     

Adaptive control of surviving symbol replica candidates in QRM-MLD for OFDM MIMO multiplexing

This paper proposes adaptive control of the number of surviving symbol replica candidates, S/sub m/ (m denotes the stage index), based on the minimum accumulated branch metric of each stage in maximum-likelihood detection employing QR decomposition and the M-algorithm (QRM-MLD) in orthogonal frequency-division multiplexing with multiple-input-multiple-output (MIMO) multiplexing. In the proposed algorithm, S/sub m/ at the mth stage (1/spl les/m/spl les/N/sub t/, N/sub t/ is the number of transmission antenna branches) is independently controlled using the threshold value calculated from the minimum accumulated branch metric at that stage and the estimated noise power. We compared the computational complexity of QRM-MLD employing the proposed algorithm with that of conventional methods at the same average packet error rate assuming the information bit rate of 1.048 Gb/s in a 100-MHz channel bandwidth (i.e., frequency efficiency of approximately 10 bit/s/Hz) using 16QAM modulation and turbo coding with the coding rate of 8/9 in 4-by-4 MIMO multiplexing. Computer simulation results show that the average computational complexity of the branch metrics, i.e., squared Euclidian distances, of the proposed adaptive independent S/sub m/ control method is decreased to approximately 38% that of the conventional adaptive common S/sub m/ control and to approximately 30% that of the fixed S/sub m/ method (S/sub m/=M=16), assuming fair conditions such that the maximum number of surviving symbol replicas at each stage is set to M/spl circ/=16.     

Expression, structure and chromosomal localization of the human cGMP-binding cGMP-specific phosphodiesterase PDE5A gene

1. Nicotinylalanine, an inhibitor of kynurenine metabolism, has been shown to elevate brain levels of endogenous kynurenic acid, an excitatory amino acid receptor antagonist. This study examined the potential of nicotinylalanine to influence excitotoxic damage to striatal NADPH diaphorase (NADPH-d) and gamma-aminobutyric acid (GABA)ergic neurones that are selectively lost in Huntington's disease. 2. A unilateral injection of the N-methyl-D-aspartate (NMDA) receptor agonist, quinolinic acid, into the rat striatum produced an 88% depletion of NADPH-d neurones. Intrastriatal infusion of quinolinic acid also produced a dose-dependent reduction in striatal GABA content. 3. Nicotinylalanine (2.3, 3.2, 4.6, 6.4 nmol 5 microl(-1), i.c.v.) administered with L-kynurenine (450 mg kg(-1)), a precursor of kynurenic acid, and probenecid (200 mg kg(-1)), an inhibitor of organic acid transport, 3 h before the injection of quinolinic acid (15 nmol) produced a dose-related attenuation of the quinolinic acid-induced loss of NADPH-d neurones. Nicotinylalanine (5.6 nmol 5 microl(-1)) in combination with L-kynurenine and probenecid also attenuated quinolinic acid-induced reductions in striatal GABA content. 4. Nicotinylalanine (4.6 nmol, i.c.v.), L-kynurenine alone or L-kynurenine administered with probenecid did not attenuate quinolinic acid-induced depletion of striatal NADPH-d neurones. However, combined administration of kynurenine and probenecid did prevent quinolinic acid-induced reductions in ipsilateral striatal GABA content. 5. Injection of nicotinylalanine, at doses (4.6 nmol and 5.6 nmol i.c.v.) which attenuated quinolinic acid-induced striatal neurotoxicity, when combined with L-kynurenine and probenecid produced increases in both whole brain and striatal kynurenic acid levels. Administration of L-kynurenine and probenecid without nicotinylalanine also elevated kynurenic acid, but to a lesser extent. 6. The results of this study demonstrate that nicotinylalanine has the potential to attenuate quinolinic acid-induced striatal neurotoxicity. It is suggested that nicotinylalanine exerts its effect by increasing levels of endogenous kynurenic acid in the brain. The results of this study suggest that agents which influence levels of endogenous excitatory amino acid antagonists such as kynurenic acid may be useful in preventing excitotoxic damage to neurones in the CNS.