The crystal structure of a polymorph of copper phthalocyanine (CuPc) grown on a KCl substrate is redetermined by transmission electron diffraction. It has a triclinic unit cell containing one molecule; the crystal does not have a herringbone-type molecular arrangement, which is a common packing mode of planar phthalocyanines. The molecular packing is determined by the diffraction intensity with the aid of the calculation of molecular packing energy. One of the striking features of this polymorph is its stacking mode within a molecular column: the molecular stacking direction projected on a molecular plane is different by an angle of about 45 degrees from that of the alpha-modifications of platinum phthalocyanine (PtPc) and metal-free phthalocyanine (H(2)Pc). A powder X-ray diffraction profile calculated for the polymorph agrees well with that of so-called alpha-CuPc and Rietveld analysis for alpha-CuPc indicates that the CuPc crystals grown on KCl are actually alpha-CuPc; hence, alpha-CuPc is not isostructural with either alpha-PtPc or alpha-H(2)Pc. On the basis of the present results and the reported crystal structures of the planar phthalocyanines that form molecular columns, the polymorphs of the phthalocyanines can be classified into four types distinguished by the molecular stacking mode within the column: alpha(x)-, alpha(+)-, beta(x)- and beta(+)-types.

The crystal growth of isotactic polystyrene (it-PS) is investigated in very thin, 11 nm thick films. The it-PS crystals grown in the thin films show quite different morphology from that in the bulk. With decreasing crystallization temperature, the branching morphology in a diffusion field appears: dendrite and compact seaweed. The branching morphology is formed through a morphological instability caused by the gradient of film thickness around a crystal; the thicker the film thickness, the larger the lateral growth rate of crystals. Regardless of the morphological change, the growth rate as well as the lamellar thickness depends on crystallization temperature as predicted by the surface kinetics.

Approximately 50% of Helicobacter pylori strains produce a cytotoxin that is encoded by vacA and that induces vacuolation of eukaryotic cells. Mosaicism in vacA alleles was reported, and there are three different families of vacA signal sequences (s1a, s1b, and s2) and two different families of middle-region alleles (m1 and m2). In addition, the vacA genotype of a strain is associated with its cytotoxin phenotype and its capacity to induce peptic ulceration. To clarify the strain diversity of H. pylori in Japan, 87 Japanese clinical isolates of H. pylori (40 from patients with chronic atrophic gastritis, 25 from patients with duodenal ulcer, 16 from patients with gastric ulcer, 3 from patients with both duodenal and gastric ulcers, and 3 from patients with intestinal type gastric cancer) were characterized by vacA typing by PCR and DNA sequencing. Eighty-four of the 87 isolates were s1a/m1, one was s1b/m1, and two could not be typed. Moreover, all isolates in this study were cagA positive. There were no distinct differences between the cytotoxin-producing strains and cytotoxin-nonproducing strains within the 0.73-kb middle region. Japanese strains were highly homologous, with more than 96% identity in this region, in which maximum divergence has been reported. In addition, there were no associations between the specific vacA types and the level of in vitro cytotoxin activity or the clinical consequences. These results indicate that the cagA-positive, s1a/m1-type strains are common in Japan, regardless of the vacA phenotype or clinical outcome.

SynopsisGlassy isotactic propylene (PP) films of thickness up to 0.3 mm were obtained by an ultraquenching technique. The structure and properties of the as-quenched and subsequently crystallized samples were characterized*by various techniques. Electron microscopy indicates the glass has no structure larger than 25 A. X-ray diffraction shows PP crystallizes from the glass into a smectic structure at ca. -20°$ and then transforms to monoclinic microcrystals at ca. 40OC; a nodular structure (80 to 100 A in diameter) was observed on the surface. The transformation temperature increases with the f i l m thickness. Annealing above the a-relaxation temperature results in an increase in the nodule size. A correspondence was found between the diameter of the nodules observed on the surface and long spacings obtained by small-angle X-ray scattering from the bulk. Dynamic mechanical spectra show the presence of two relaxation-like peaks at ca. -10°C and 10°C for the as-ultraquenched samples. X-ray scattering, differential scanning calorimetry (DSC), and torsion pendulum measurements show PP crystallizes from the glass at a temperature, depending on the rate of heating, that corresponds to the lower relaxation peak temperature.

Dynamics of thin films of poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) have been investigated by dielectric relaxation spectroscopy in the frequency range from 0.1Hz to 1MHz at temperatures from 263K to 423K. The α-process, the key process of glass transition, is observed for thin films of PVAc and PMMA as a dielectric loss peak at a temperature Tα in temperature domain with a fixed frequency. For PMMA the β-process is also observed at a temperature T β . For PVAc, Tα decreases gradually with decreasing thickness, and the thickness dependence of Tα is almost independent of the molecular weight (Mw ≤2.4×10 5 ). For PMMA, Tα remains almost constant as thickness decreases down to a critical thickness dc, at which point it begins to decrease with decreasing thickness. Contrastingly, T β decreases gradually as thickness decreases to dc, and below dc it decreases drastically. For both PVAc and PMMA, the broadening of the distribution of the relaxation times in thinner films is observed and this broadening is more pronounced for the α-process than for the β-process. It is also observed that the relaxation strength is depressed as the thickness decreases for both the polymers.

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RESULTS. Of 70 -90% of patients with gastric adenocarcinoma. The epidemiologic features of gastric adenocarcinoma and H. pylori infection are similar,

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