Three-dimensional structure of protein C inhibitor predicted from structure of {alpha}1-antitrypsin with computer graphics

The three-dimensional structure of a proteolytically modifiedprotein C inhibitor, a member of the serine protease inhibitorsuperfamily, was constructed with computer graphics based onits amino acid sequence homology with that of the modified 1-antitrypsinwhose structure had been elucidated by X-ray crystallography.The intact form of protein C inhibitor was predicted with an-carbon model based on its hydrophilicity and hydrogen bondpattern. Furthermore, a model of its interaction with activatedprotein C was constructed based on the structure of the complexbetween trypsin and its inhibitor, which had been determinedby X-ray crystallography.     

Diffusion measurements on a liquid monotectic alloy PbGa using the shear cell technique under µg in the foton-M2 mission and under 1G

Diffusion experiments of a liquid monotectic alloy PbGa were performed under 1g-conditions at 623, 773 and 903K, and under µg-conditions at 903K. As a measurement tool the shear cell specially designed for Russian satellite Foton missions within the AGAT-furnace was used to have a homogenization time before the diffusion and to avoid the influence of decomposition into two liquid phases during cooling-down. The experiment type was diffusion from a thick layer of PbGa5at% into pure Pb. The liquid sample in the capillary was pressurized using a reservoir system in order to minimize Marangoni convection. In 1g-experiments the diffusion axis was arranged vertically and the sample was set such that the density increases monotonously parallel to the gravity vector in order to suppress buoyancy convection. Four experiments were performed simultaneously for each set-up. The µg-experiment was performed in the AGAT facility during the Foton-M2 mission (June 2005) where one capillary was assigned for the PbGa-Pb experiment (PbGa was containing an enriched Pb-isotope tracer). The concentration profiles were obtained by AAS (1g) and by ICP-MS (µg). The diffusion coefficients were evaluated by fitting with the thick layer solution. For the evaluation a correction method was used for the shear convection and the averaging effect inside each cell. As a result, the obtained concentration curves agreed well with the fitting function. The reproducibility of the diffusion coefficients among four parallel 1g-experiments was good with a standard deviation among four capillaries smaller than 5.5% including the standard temperature deviation. The diffusion coefficients agreed well between 1g- and µg-experiments. The temperature dependence of the diffusion coefficients could be fitted well to a power law with an exponent about 2.4. From these results we conclude that the 1g-experimental method in this study for diffusion measurement is effective also for monotectic systems.     

Analysis of the 300 MHz pmr spectrum of poly(2-vinyl thiophene)

Summary The 300 MHz pmr spectrum of poly(2-vinyl thiophene), poly-2-VT, is presented and analyzed. The aliphatic proton resonance of this polymer is very similar to that of polystyrene, but the aromatic proton resonance is rather well defined, especially that of protons in the 3-position of the thiophene ring. The resonance of such protons occurs as a three peak pattern that has been interpreted in terms of pentad stereosequences. Based on the assignments made in this paper, poly-2-VT prepared by free radical initiated polymerization seems to be atactic.     

Application of finite-element method to H-plane waveguide discontinuities

The finite-element method has been applied to the scattering by an inhomogeneous H-plane discontinuity of arbitrary shape in a rectangular waveguide. As an example of the method, a right-angle corner bend and a waveguide-type dielectric filter are considered. Our results agree well with earlier theoretical and experimental results.     

Z-type jump in electrical conductivity of samarium manganite

The electrical conductivities of non-stoichiometric samarium manganites were measured as a function of temperature and the existence of a Z-type jump in the conductivity curve was found near 1300 K, and a heat anomaly was also observed by differential thermal analysis, which should reflect the same phase transition as in LaMnO₃.     

Characterization of monolayer and bilayer (polymer/monolayer) structures for their use as a lubricant

To help to understand lubrication in order to design a good lubricant, a glass surface is modified by various monomolecular layers or bilayers (polymer on monolayer) and their effects on the coefficient of friction are examined. In a bilayer structure the monolayer is used as a binder between the polymer and the substrate. Monolayers are deposited by vapour phase deposition or the Langmuir-Blodgett technique. Polymers are spin coated after monolayer deposition. The coefficient of friction is lowered to a minimum of about 0.1 by these modifications. There is a parallelism between surface energy and coefficient of friction. However, it is found that the surface energy is not the only factor that effects the lubrication, i.e. although the surface energy is similar the coefficient of friction is smaller when (1) the surface is modified by a bilayer rather than by a monolayer, (2) the polymer viscosity is higher, (3) the polymer is liquid rather than solid at room temperature and (4) the reactivity between polymer and monolayer is higher. It has been deduced that a high molecular weight fluorinated polymer, which can be effectively bound to a surface, will be a good lubricant.