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The periodical striped contrast is observed in the single crystals of isotactic polystyrene and poly(oxymethylene) by transmission electron microscopy. The contrast is attributed to a periodical tilting of the chain stem around the axis normal to the crystal growth plane; the tilting accompanies the surface undulation, which is observed by atomic force microscopy. The wavelength of the undulation increases with the lamellar thickness. In situ observation of the growing crystal by transmission electron microscopy shows that this undulation is introduced during the growth and not through the cooling process of the crystal. It is proposed that the stress of fold surfaces makes a flat lamellar crystal elastically unstable to cause the buckling deformation during the crystal growth.

A new strategy for the asymmetric synthesis of chiral primary α-ferrocenylalkylamines has been utilized to generate homochiral redox-active receptors that bind chiral carboxylate anions with moderate enantioselectivity and undergo a redox response to complexation

Abstract:  In this paper, we have applied genetic programming to generate an optimal architecture of neuro force controllers for robot manipulators in any environment. In order to perform precise force control in unknown environments, the optimal structured neuro force controller is generated using genetic programming with fuzzy fitness evaluation. After the architecture of the neuro controller has been optimized for any kinds of environments, it can be applied for a robot contact task with an unknown environment in on-line manner using its own adaptation ability. An effective crossover operation is proposed for the efficient evolution of the controllers. The simulation has been carried out to evaluate the effectiveness of the proposed robot force controller.

The synthesis and chemical properties of a variety of chemically modified calix[4]pyrroles are described. The effects of structural changes, specifically the presence and absence of substituents on the meso-like and β-pyrrolic carbons, on anion affinities are detailed as is their effect on macrocycle conformation. Also described are unsymmetrical systems, bearing an aliphatic and aromatic substituent on each of the four meso-like carbon atoms. In this case, the properties of the resulting configuration isomers are discussed in terms, again, of the resulting effects on macrocycle conformation and substrate binding affinity. Finally, the use of appropriately functionalized calix[4]pyrrole systems as rudimentary fluorescence-based anion sensors is presented.

Isothermal crystallization process of isotactic polystyrene at 167°C has been studied by smallangle x-ray scattering. The observed SAXS intensities consist of the twophase lamellar structure component, the density fluctuation, and the foreign particle components. The profile of lamellar structure component remains unchanged during crystallization while its intensity increases with crystallization. The lamellar structure of isotactic polystyrene is investigated on the basis of the interface distribution function. An interface distribution function is obtained from the lamellar structure component after correcting the effect of the finite thickness of boundary regions between crystalline and amorphous phases. In order to obtain the structure parameters, the “Gaussian correlation model” is used, in which the correlation between the distributions of neighboring crystal and amorphous thicknesses is taken into account. Agreement is satisfactory between the experimental results and the calculations. The structure parameters of isotactic polystyrene are determined for isothermal crystallization at 167°C as follows: the average and the standard deviation of crystal thickness are 40 A and 10 A, respectively, those of amorphous thickness are 70 A and 23 A, and the standard deviation of long period is 31 A.

Primary and acquired resistance to antibiotics is an important factor in determining the reason for treatment failure in Helicobacter pylori infection. We examined the relationship between the susceptibility of H. pylori isolates and the efficacy of chemotherapy.

Electron microscope studies of as-ultraquenched and subsequently crystallized isotactic polybutylene (PB) are described in this paper. Cold shadowing of the as-quenched samples reveals no distinct structure larger than 30 Å in the amorphous PB. When rapidly warmed to room temperature PB crystallizes as microcrystals of size ranging from 100 to 250 Å. The size of the microcrystals can be changed only by annealing at temperatures higher than Tα; in PB this resulted in the growth of short lamellae. However, by warming the quenched samples slowly to room temperature, large morphological units were obtained. The effect of several quenchants on the crystallization process of PB is also discussed.

A number of years ago the morphology of amorphous polyethylene terephthalate (PET) quenched from the melt at 280°C into ice water and cast from solution was reported [1]. A nodular structure ca. 75 Å in diameter was described, the electron diffraction pattern consisting of a single diffuse ring. Based on brightfield and dark-field diffraction contrast micrographs, which showed the presence of ordered domains of similar size, it was proposed that the molecules in amorphous PET both above and below Tg are locally aligned and have a nematic liquid-crystal-like arrangment, in domains of the size of the nodules. The proposal of order in the amorphous material above Tg was based on the assumption that the quenching was sufficiently rapid that the morphology observed in the glass reflected that present above Tg at the instant of quenching; in the melt itself the ordered domains were presumed to undergo continuous fluctuation.

The high pressure phase of several kinds of dicarboxylic acid (DCA) has been studied by X-ray diffraction up to 700 MPa and compared with the hexagonal phase of polyethylene (PE) under high pressure. Eicosanedioic acid (DCA-20) is the shortest DCA investigated that has the high pressure phase. The phase diagram of DCA-20 is determined. Water plays an essential role for the transition from the monoclinic to the hexagonal form; in the absence of water, the monoclinic form directly melts without passing through the hexagonal form. Low molecular weight PE treated by fuming nitric acid is a DCA with a long methylene chain and also has the hexagonal form only in the water as a pressure transmitting fluid. The mechanism of the transition is discussed in the light of hydration of the carboxyl groups on the crystal surface and flexibility of the molecule depending on the length of methylene chain.

A martensitic transformation is found in single crystals of 1, 20-eicosanedioic acid. It has been studied by optical microscopy and X-ray diffraction, using diamond anvil cells and a cold stage. The new phase has a triclinic crystal structure. The transformation from the monoclinic (ordinary form) to the triclinic phase occurs mostly between 5 and 10kbar on applying hydrostatic pressure at room temperature, and between - 50 and-70°C on cooling at 1 atm (the transformation pressures and temperatures varied from crystal to crystal). The reverse transformation occurs at about room temperature and 1 atm in both cases. The lattice constants of the triclinic phase at room temperature are a =27·9, b = 5·56, c = 814 Å, α = 79·3°, β=113·9°, γ= 116·4° at 1 atm and a = 27·8, fc = 5·37, c = 7-7Å, a = 79°, β=115°, γ=117° at 7.7kbar. From the lattice constants and from optical microscopy, the transformation is shown to proceed by simple shear. The shear plane and shear direction are (01 l)m, [100]m or (0l1)m, [100]m for the transformation and (0l1), [100], for the reverse transformation. The magnitude of shear is 0-61; each {011 }m or (011), plane slips relative to the others by 2-4-2.6 Å along the chain axis.

The lateral crystal habits of n-alkanes (n-CnH2n+2) have been observed just below the melting points by optical microscopy for n=18, 19, 20, 22, 24, 34, 44, 50 and 65. The shape of the crystals depends on the crystal phase: circular in the rotator phase, lenticular in phase C, and diamond in the low-temperature phase. The rounding of the lateral shape can be explained in terms of thermal roughening of the lateral faces in the disordered phases at high temperature.

We compared the antitumour effects of glycosylated LT (gLT), nonglycosylated LT and TNF against a solid tumour in mice. We found that: (a) The systemic administration of gLT showed significant antitumour activity. These effects were, however, quite small in nude mice. Nonglycosylated LT and TNF attained the same degree of effectiveness as gLT, but at a 5-times higher dose. The serum half-life of gLT was 3-fold longer than that of nonglycosylated LT and 22-fold longer than that of TNF. (b) The effect of gLT was significantly blocked by pretreatment with anti-asialo GM1 antibody. Treatment with gLT produced a significant reduction in numbers of tumour-regional mononuclear cells, which in turn, produced increases intensive necrosis. (c) Mononuclear cells in the tumour tissues before gLT-injection were predominantly IL-2 receptor +/CD3- cells and CD3+ cells. Pretreatment with the anti-asialo GM1 antibody produced a drastic reduction of IL-2 receptor +/CD3- cells. These findings suggest that the efficient antitumour effect of gLT is due to a longer serum half-life than that of nonglycosylated LT or TNF in vivo, and its function is largely mediated by IL-2 receptor +/CD3- cells.

The decomposition of urea adducts with hydrocarbons is treated as a first-order phase transition and the pressure dependence is studied up to 0.7 GPa for several kinds of adducts. The thermodynamic quantities at the decomposition of the adduct can be analysed as a sum of those quantities of the component materials. The transition from the orthorhombic to the hexagonal form of the adduct with polyethylene is also investigated by X-ray diffraction and the pressure dependence of the lattice parameters is measured for the adducts. The results are compared with the phase transition in the pure paraffin.

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.

The lateral crystal habits ofn-alkanes (n-CnH2n+2) have been observed just below the melting points by optical microscopy forn=18, 19, 20, 22, 24, 34, 44, 50 and 65. The shape of the crystals depends on the crystal phase: circular in the rotator phase, lenticular in phase C, and diamond in the low-temperature phase. The rounding of the lateral shape can be explained in terms of thermal roughening of the lateral faces in the disordered phases at high temperature.