Target validation and ligand development for a pathogenic fungal profilin,using a knock‐down strain of pathogenic yeast Candida glabrata and structure‐based ligand design

The emergence of antifungal drug resistance is triggering vigorous searches for novel antifungal targets and lead compounds. In this study, we focused on fungal profilin, which is a small actin control protein sharing limited homology to human profilin. To validate its potentiality as a target, a profilin‐conditional mutant of the pathogenic yeast Candida glabrata was constructed, using a regulatable Tet promoter, and its growth was monitored in vitro. Repression of profilin expression led to severe growth defect, demonstrating the potential of this protein as a novel antifungal target. Next, novel peptides binding to the active interface of profilin were designed by computer simulation. ELISA analysis showed that these peptides did bind to the wild‐type profilin but bound less strongly to a profilin with amino acid substitutions at the active interface. Hence, we show here that profilin is a potential antifungal target and offer novel peptide ligands. Copyright © 2010 John Wiley & Sons, Ltd.     

Crystal structures and electrical properties of titanium films evaporated in high vacuum

Thin titanium films were deposited on glass substrates maintained at various elevated temperatures. X-ray studies showed that higher substrate temperatures caused growth of the $\text{{10}\text{1}\text{1}}$ orientation in preference to the {0002} orientation and also increased the grain size in the films. The dependences of the electrical resistivity and the Hall coefficient on the substrate temperature were investigated: the variation of the resistivity with substrate temperature can be explained qualitatively in terms of the grain sizes of the films, but the main feature of the Hall coefficient was found to be closely related to the differences in preferred orientation of the crystals.     

Specific interaction of starch and polyvinyl alcohols having long alkyl groups

Properties of aqueous solutions of blends of starch and polyvinyl alcohols (PVAs), having alkyl groups as side chains, or at one polymer chain end, were studied in terms of viscosity stability, and transparency. In the case of corn starch, PVAs having butyl, octyl, and dodecyl end groups, as well as PVA copolymers containing small amounts of vinyl versatate, together with itaconic acid, increased the stability of the blended solution. The aqueous solutions of PVA, having dodecyl end groups and oxidized starch blend, also showed good stability in viscosities and considerable increase in transparency, whereas conventional PVA and oxidized starch blend gave turbid aqueous solutions, followed by phase separation. The phenomena were assumed to arise from the interaction of the alkyl group in PVA with starch, forming a helical structure with the alkyl group in the hydrophobic internal part.     

Electrical conductivity of a sintered pellet of octalithium zirconate

The conductivity of a sintered pellet of Li₈ZrO₆ was measured in dry or wet argon atmosphere by the two-terminal technique with an AC Wheatstone bridge in the temperature range 350–1050 K. The temperature dependence of conductivity multiplied by temperature $\text{(σT)}$ of Li₈ZrO₆ in a dry environment had two transition points at 426 and 833 K. The activation energies of conductivity in high, middle and low temperature regions were 103.2, 52.1 and 37.4 kJ/mol, respectively. The activation energies of conductivity agreed well with those obtained by temperature dependence of spin-lattice relaxation time $\text{T}{}_1$ of ⁷Li with pulsed nuclear magnetic resonance.     

Formation and structure of organized molecular films for organo‐modified montmorillonite and mixed monolayer behavior with poly(L‐lactide)

We investigated the molecular orientation and surface morphology of organized molecular films with regard to solid‐state structures for organo‐modified montmorillonites by surface pressure‐area (π ? A) isotherm, in‐plane and out‐of plane X‐ray diffraction (XRD), and atomic force microscopy (AFM). From the results of out‐of plane XRD, formation of highly ordered layer structure was confirmed in these clay Langmuir‐Blodgett (LB) film. Further, two‐dimensional lattice of long alkyl chain of organo‐modified parts packed hexagonally or orthorhombically in the films. Surface morphology of Z‐type monolayers on solid of organo‐modified montmorillonites indicates heterogeneous modification ratio in montmorillonite surface by AFM observation. In addition, monolayer behavior on the water surface and mesoscopic morphological formation on solid of mixed films of organo‐modified montmorillonite and poly‐(L ‐lactide) (PLLA) were investigated by π ? A isotherm and AFM. Collapsed surface pressures are independent on the mixed ratio, and indicate almost constant value in their isotherms. This tendency is a peculiarity of immiscible system. From the result of AFM observation, phase separated structure was confirmed in mesoscopic scales. This phase separated morphology remarkably varied with mixed ratio. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Joint properties and its improvement of high-tensile strength steel joint by autocompleting friction welding method

This paper describes the improvement of properties of a high-tensile strength steel joint by an autocompleting friction welding method that was developed by the authors. The base metal was high-tensile strength steel of 800 MPa class. The weld faying surface of the fixed specimen had a 10 mm diameter, and the effect of the thickness and that at the bottom of the grooves (groove bottom thickness) for the insert piece on the joining phenomena and joint properties were investigated. The value of a circumferential shear fracture (CSF value) was defined and calculated by the ratio between the theoretical and the actual generated friction torques. When the CSF value was lower than 1, the insert piece had the CSF before the friction torque reached the initial peak. Also, when the CSF value was larger than 1, the insert piece had the CSF after the friction torque reached the initial peak. When the joint was made at the insert thickness of 5 mm with the CSF value of nearly 1, it had 100% joint efficiency although it had the softened region near the weld interfaces. The joint had cracks at the weld interface when it was made with friction pressures of 36 and 120 MPa. However, the joint had no crack at the weld interface when it was made with a friction pressure of 90 MPa. When the joint was made at the insert thickness of 4 mm with the CSF value of nearly 1, it had also 100% joint efficiency although it had the softened region near the weld interfaces. However, the softened region at the weld interface of the joint with the insert thickness of 4 mm was lower than that with 5 mm. Also, this joint had 90° bend ductility with no crack at the weld interface. In conclusion, it was possible to make a joint with no cracks for high-tensile strength steel by an autocompleting friction welding method.     

中碳调质钢焊接区氢致裂纹行为的直接观察

本研究对铬镍系中碳调质钢(SNC631)的高温充氢试件及焊接试件中,氢致裂纹的宏观与微观行为,用光学显微镜及电镜进行了直接观察与记录。并对氢致裂纹萌生及扩展的某些机理,诸如微裂纹与塑性变形的关系,热影响区微裂纹的萌生与硫化物夹杂的关系,以及断裂形式与显微组织的关系等问题,有了进一步的认识。