Production of equol from daidzein by gram-positive rod-shaped bacterium isolated from rat intestine

Isoflavones (mainly daidzein and genistin) belong to the flavonoid group of compounds and are classified as phytoestrogens. In the intestine, daidzin is converted to daidzein by beta-glucosidase, and then daidzein is converted to O-desmethylangolensin (O-DMA) or equol via dihydrodaidzein by enzymes of intestinal bacteria. We isolated, for the first time, an anaerobic gram-positive rod-shaped strain capable of producing equol from daidzein. Its 16S rDNA gene sequence (1428 bp) showed 99% similarity with that of the human intestinal bacterium SNU-Julong 732 (AY310748) and 93% similarity with that of Eggerthella lenta ATCC 25559(T) (AF292375). This strain converted daidzein to equol via dihydrodaidzein in an equol-assay medium anaerobically. The addition of butyric acid and arginine increased the conversion ratio of daidzein to equol 4.7- and 4.5-fold, respectively.     

Use of drinking protective behavioral strategies in association to sex-related alcohol negative consequences: The mediating role of alcohol consumption.

Alcohol use has been implicated as a risk factor for sexual negative consequences, such as unprotected sexual intercourse. The present research was conducted to examine the relationship between drinking protective behavioral strategies and consensual sex-related alcohol negative consequences, and whether this relationship varied by gender. Additionally, typical number of drinks during sexual behavior was evaluated as a potential mediator of this association. Heavy drinking, sexually active college students (N = 297, 50.2% women) completed self-report measures of drinking protective behavioral strategies, alcohol consumption, and sex-related alcohol negative consequences. Findings indicated that women who used drinking protective behavioral strategies more frequently were less likely to experience sex-related alcohol negative consequences whereas this relationship was not significant for men. For women, this relationship was mediated by the typical number of drinks consumed during sexual behavior. The current research demonstrates that use of drinking protective behavioral strategies is related to a reduction in women's sex-related risks when drinking. Findings are discussed in terms of alcohol myopia theory. Implications for interventions aimed to reduce higher risk sexual behavior among college students are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Random thermal fatigue in fast breeder reactor: a narrow-band spectrum

Thermal fatigue crack growth in a fast breeder reactor is theoretically investigated with the aid of probabilistic fracture mechanics (PFM) under the conditions that (i) the temperature variation is a narrow-band stationary process and (ii) the crack grows owing only to the peak stress variation. First, a statistical property of residual life of the component with single crack is derived in an analytical form with the aid of an extended Markov approximation method, which is an efficient mathematical technique in PFM. Next, discussion is carried out on the generalization of the primitive model to the case with plural cracks, where a stress relaxation factor is introduced to express a stress intensity factor of each crack. Finally, a numerical example is shown to examine the quantitative behavior of the component's residual life, and sensitivity analysis is performed with respect to some model parameters.     

Hydrophilic affinity isolation and MALDI multiple-stage tandem mass spectrometry of glycopeptides for glycoproteomics

In glycoproteomics, key structural issues, protein identification, locations of glycosylation sites, and evaluation of the glycosylation site microheterogeneity should be easily evaluated in a large number of glycoproteins, while mass spectrometry (MS) provides substantial information about individual purified glycoproteins. Considering that structural issues are elucidated by studying glycopeptides and that the tandem MS of a tryptic peptide composed of several amino acid residues is enough for protein identification, construction of an MS-based method handling tryptic glycopeptides would be of considerable benefit in research. To this end, a simple and efficient method, utilizing hydrophilic binding of carbohydrate matrixes such as cellulose and Sepharose to oligosaccharides, was successfully applied to the isolation of tryptic glycopeptides. Both peptide and oligosaccharide structures were elucidated by multiple-stage tandem MS (MS(n)) of the ions generated by matrix-assisted laser desorption/ionization (MALDI), as follows. The MALDI ion trap mass spectrum of a tryptic glycopeptide mixture from N-linked glycoproteins was composed of the [M + H]+ ions of component glycopeptides. Collision-induced dissociation (CID) of the glycopeptide [M + H]+ ion generated saccharide-spaced peaks, with an interval of, for example, 146, 162, and 203 Da, and their fragment ions corresponding to the peptide and peptide + N-acetylglucosamine (GlcNAc) species in the MS2 spectrum. The saccharide-spaced ladder served to outline oligosaccharide structures, which were then selected as precursors for subsequent MS(n) analyses. The peptide or peptide + GlcNAc ions in the MS2 spectrum or the corresponding ions abundant in the MS1 spectrum were subjected to CID for determination of peptide sequences, to identify proteins and their glycosylation sites. The strategy, isolation of glycopeptides followed by MS(n) analysis, efficiently characterized the structures of beta2-glycoprotein I with four N-glycosylation sites and was applied to an analysis of total serum glycoproteins.     

Tribological properties of densely packed vertically aligned carbon nanotube film on SiC formed by surface decomposition

Characteristic tribological properties, such as nonlinearity of the friction force-normal load curve, high coefficient of friction, and good wear-resistant performance were observed on densely packed, vertically aligned carbon nanotubes (CNTs) with different diameters and lengths using atomic force microscopy. Shorter and thicker CNTs were found to have higher coefficients of friction. The observed properties were attributed to the nonlinear elastic property of the CNTs caused by buckling.     

Discriminative detection of volatile sulfur compound mixtures with a plasma-polymerized film-based sensor array installed in a humidity-control system

We demonstrated the discrimination of volatile sulfur compound mixtures with different mixing ratios by using an array of the plasma-polymerized film (PPF)-coated quartz crystal resonators. The PPF sensor array, which contains PPFs prepared from amino acids and synthetic polymers, exhibited different response patterns to mono or mixed volatile sulfur compounds (VSCs) (hydrogen sulfide and methanethiol) under a dry environment. The sensor array was installed in a desktop-size relative humidity controller. The relative humidity and temperature conditions of the sample flow to the sensor cell were equalized to those of the inner atmosphere of the sensor cell based on the concept of the two-separate-temperatures method. In this way, the baseline drift of PPF sensor response caused by the introduction of a highly humid sample was successfully suppressed. We compared the sensor array responses under the controlled humidity conditions. Presorption of water molecules by PPFs caused a decrease of sensor sensitivity, but the films still had the ability to discriminate sub-ppmv VSC mixtures having 6:1, 1:1, and 1:6 mixture ratios of hydrogen sulfide and methanethiol.     

Correlated firing in a feedforward network with Mexican-hat-type connectivity

We report on deterministic and stochastic evolutions of firing states through a feedforward neural network with Mexican-hat-type connectivity. The prevalence of columnar structures in a cortex implies spatially localized connectivity between neural pools. Although feedforward neural network models with homogeneous connectivity have been intensively studied within the context of the synfire chain, the effect of local connectivity has not yet been studied so thoroughly. When a neuron fires independently, the dynamics of macroscopic state variables (a firing rate and spatial eccentricity of a firing pattern) is deterministic from the law of large numbers. Possible stable firing states, which are derived from deterministic evolution equations, are uniform, localized, and nonfiring. The multistability of these three states is obtained where the excitatory and inhibitory interactions among neurons are balanced. When the presynapse-dependent variance in connection efficacies is incorporated into the network, the variance generates common noise. Then the evolution of the macroscopic state variables becomes stochastic, and neurons begin to fire in a correlated manner due to the common noise. The correlation structure that is generated by common noise exhibits a nontrivial bimodal distribution. The development of a firing state through neural layers does not converge to a certain fixed point but keeps on fluctuating.     

Bromination of silk fabrics

The bromination of silk fabrics was studied under heterogeneous conditions in N,N-dimethylformamide using three reagent systems, molecular bromine, methanesulfonyl bromide (MsBr), and N-bromosuccinimide (NBS)-triphenylphosphine (PPh₃) in combination with sodium bromide. Molecular bromine brominated tyrosine residues selectively and consecutively to 3-bromotyrosine and 3,5-dibromotyrosine residues. MsBr reacted only with serine residues to give 3-bromoalanine (Br-Ala) residues. The addition of sodium bromide to the NBS-PPh₃ system suppressed the bromination of tyrosine residues and slightly increased the yield of Br-Ala residues. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2031–2036, 1997