Structural studies on a sulfated polysaccharide from an Arthrobacter sp. by NMR spectroscopy and methylation analysis

Interleukin-4 (IL-4) is a pleiotropic immunomodulatory cytokine secreted by T helper 2 cells. The IL-4 promoter contains multiple sites with DNA sequences homologous to the IL-2 NF-AT binding site. One of these sites--the P2 site--located between -173 and -150 was previously found to be flanked by two octamer-like motifs. NF-ATp/c and octamer proteins were suggested to bind to this region and to cooperatively activate the promoter activity (Chuvpilo et al., 1993). To precisely analyze the P2-binding factors we used antibodies against NF-ATp, NF-ATc, Fos, Jun, Oct-1 and Oct-2 in EMSA. We show here that nuclear extracts from T-cells form two P2-binding complexes--a PMA/ionomycin-inducible and a constitutive one. The PMA/ionomycin-inducible complex contains NF-ATp/c, Fos and Jun. No octamer binding factors could be detected in either of the two complexes. Analysis of the precise DNA contact points of the two complexes showed that both complexes are formed in the center of the NF-AT consensus site. No DNA contact points could be detected in the octamer-like motif site. Furthermore, purified recombinant POU domains of Oct-1 and Oct-2 failed to bind to the P2 site, suggesting that this site is not an independent octamer-binding site. Therefore, the DNA sequence at -173 to -150 of the IL-4 promoter is a binding site for NF-ATp/c and AP-1. Octamer proteins are unlikely to cooperate with NF-ATp/c at this site.     

Tribological properties of Fe7Mo6-based alloy under two ionic liquid lubrications

The tribological properties of Fe₇Mo₆-based alloy, Mo, Fe and ASTM class no. 45 cast iron disk specimens were investigated against ASTM 52100 steel balls under the lubrication of two different kinds of hydrophobic ionic liquid: N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13-TFSI) and N-N-N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (TMPA-TFSI). When lubricated with PP13-TFSI or TMPA-TFSI, the Fe₇Mo₆-based alloy disk specimens exhibited lower friction coefficients and lower wear rates than the Mo, Fe and ASTM class no. 45 cast iron disk specimens. The low friction coefficients and low wear rates of the Fe₇Mo₆-based alloy were considered to be caused by the formation of low friction materials such as MoO₃ and FeSO₄ on the worn surface.     

Geographical origin of polished rice based on multiple element and stable isotope analyses

We determined carbon and nitrogen contents (C and N contents) and stable carbon, nitrogen, and oxygen isotopic compositions (δ¹³C, δ¹⁵N, and δ¹⁸O) of polished rice in order to develop a simple method to discriminate its geographical origin. As a first attempt, we examined a single cultivar, Koshihikari rice, from 14 different cultivation areas including Australia (n = 1), Japan (n = 12), and USA (n = 1). For all rice samples, C and N contents and the isotopic compositions are consistent with those of general plant materials, being 37.2–40.0% (C content), 0.8–1.4% (N content), −27.1 to −25.4% (δ¹³C), +0.4 to +9.0% (δ¹⁵N), and +18.8 to +22.9% (δ¹⁸O). However, its cultivated area is clearly distinguished by a pentagonal radar plot based on the elemental and isotopic compositions. Thus, the comparison of C and N contents and δ¹³C, δ¹⁵N, and δ¹⁸O values would potentially be useful for rapid and routine discrimination of geographical origin of the polished rice.     

Dynamic Chirality Control of (Xyl‐)BIPHEP Ligands Leading to their Diastereomerically Pure Ru Complexes with a Chiral N‐Substituted DPEN

The metal complex of the chirally flexible biphenylphosphine (BIPHEP) exists as an equilibrium between the enantiomeric pairs due to the flexibility of BIPHEP. The dynamic chirality control of the BIPHEP ligands in enantiomerically pure forms to give diastereomerically pure metal complexes with respect to their Ru(II) complexes by their molecular design with the introduction of a substituent in the chiral diamines rather than in the biphenylphosphine is described.     

Structural study on a sulfated polysaccharide-peptidoglycan complex produced by Arthrobacter sp

The structure of a sulfated polysaccharide-peptidoglycan complex (SP-PG) produced by Arthrobacter sp. was analyzed by NMR spectroscopy. In addition, oligosaccharide fragments of the SP-PG-L obtained by HF degradation were analyzed by NMR spectroscopy. These findings indicated that the sulfated polysaccharide (SP) contains a repeating unit composed of two galactofuranosides and a glucopyranoside. The main chain of the trisaccharide is [-->6) beta-D-Galf(1-->6)-beta-D-Galf(1-->ln, with beta-D-Glcp linked to one of the Galfs through a (1-->2) linkage. The sulfated positions of the trisaccharide were identified as C-3 and C-5 of the beta-glucosylated Galf residues, and C-2 or C-3 of the other Galf residue.     

Effect of small openings on strength and stiffness of shear walls in reactor buildings

A total of 26 wall specimens were tested to examine the effect of small openings on the strength and stiffness of shear walls in reactor buildings. The parameters tested were the shape, number and local arrangement of the openings, and the reinforcing method around the openings. Reversed cyclic loads were applied to the specimens, and their strengths and restoring force characteristics were compared with each other to understand the effects of these parameters. Based on the test results, two methods for predicting the shear strength of walls with numerous small openings are examined. One is a method to calculate directly the strength along assumed failure lines, and the other method allows estimation of the strength reduction factors for design, taking account of the effect of openings. Both methods are found to be useful to estimate roughly the strength of such shear walls. It is also shown that the stiffness of such walls could be evaluated using a combined multi-spring model. For the reinforcing methods around openings, a simplified reinforcing method is proposed and the effectiveness of the method is discussed by checking the contribution of the reinforcement to the wall strength.     

Friction and wear properties of Fe–Mo intermetallic compounds under oil lubrication

In this study several disc specimens of three different compositions of the Fe–Mo system were prepared by spark plasma sintering and annealing, and their friction and wear properties were investigated. It was found that, when ASTM 52100 steel balls were used as the paired materials, both the Fe–42 at% Mo and Mo disc specimens exhibited lower friction coefficients and lower wear rates than the Fe and cast iron disc specimens. It was also found that the spark plasma-sintered Fe–42 at% Mo disc specimens without any heat treatments exhibited lower friction coefficients than those annealed at 1323 K for 172.8 ks. According to the XPS analysis, iron oxides and iron sulfides were found on the worn surfaces of the Fe disc specimens that were slid against the ASTM 52100 steel balls, while molybdenum oxides such as MoO₂, but not MoS₂, were observed on the worn surfaces of the annealed Fe–42 at% Mo and Mo disc specimens that were slid against the steel balls.     

Nanoscale to Macroscale Investigation of the Frictional Properties of Physisorbed Layers of Self-Organized Phthalocyanine Derivatives

The frictional properties of molecules physisorbed on a graphite surface were investigated on the macroscale using a pin-on-plate tribometer and on the nanoscale using atomic force microscopy (AFM). Hydrodynamic lubrication was observed even at a contact pressure of about 1 GPa under the AFM tip. Selection of the Stribeck parameter of η _eff V/(W/R), which accounts for the change in effective viscosity, is proved effective for comparing the frictional properties of the physisorbed layers of self-organized molecules on nanoscale with the properties on macroscale.     

Applying Micro-Texture to Cast Iron Surfaces to Reduce the Friction Coefficient Under Lubricated Conditions

The tribological properties of cast iron have been investigated to determine the effects of micro-texturing the surfaces. The micro-textured surfaces were prepared by shot blasting or milling using a shaper. The surfaces with groove patterns and mesh patterns had higher friction coefficients than the flat surfaces. The surfaces with dimpled patterns had lower friction coefficients than the flat surfaces. The results indicated that the dimpled pattern had a beneficial effect by decreasing the friction.