Cementite dispersed in carbons from ferrocene,vinylferrocene, divinylbenzene systems

Cementite-dispersed carbon was synthesized by pressure pyrolysis of divinylbenzene-vinylferrocene and divinylbenzene-ferrocene below 600° C. The magnetization of divinylbenzeneferrocene polymer was higher than that of divinylbenzene-vinylferrocene copolymer at temperatures from 300 to 400° C. The saturation magnetization of cementite-dispersed carbon formed above 500° C was dependent only on the iron concentration in the carbon matrix. The coercive force of cementite-dispersed carbon synthesized from divinylbenzene -vinylferrocene copolymer was about 900 Oe as a maximum value, whereas divinylbenzene-ferrocene polymer gave cementite-dispersed carbon with lower coercive force of 200 Oe. The size of cementite particles dispersed in the carbon from divinylbenzene-vinylferrocene copolymer was less than 50 nm diameter, while divinylbenzene-ferrocene (DVB-Fc) polymer gave a carbon containing larger particles up to 130 nm. The feasible initial aggregation of paramagnetic species in DVB-Fc polymer gave large particles of cementite with multiple magnetic domain. Fixation of ferrocene by the carbon-carbon bond to the parent polymer matrix was found to be effective for fine dispersion of cementite particles in the resultant carbon.     

On the Interpretation of some Visual Illusions by a Geometrical Model of Riemannian Spaces

Behaviormetrika - The visual spaces with some visual illusions are discussed from the point of Riemannian geometry. On the assumption that each local visual space is furnished with parallel lines...     

Heat treatment of mesocarbon microbeads under high pressure

Mesophase spherules separated from pitches and asphalt by quinoline (mesocarbon microbeads) were heat-treated under a pressure of 5 kbar at 1300–2000°C for 1 hr. The as-separated microbeads gave a bulk density of 1.8–1.9 g/cm³ after heat treatments at high temperatures. The pre-heated microbeads gave high bulk density above 2.0 g/cm³ after high temperature heat treatment. The mesocarbon microbeads were found to have low graphitizability under pressure. The as-separated microbeads showed a heterogeneous process of graphitization, but the maximum amount of the graphitic component was only 60% even after 2000°C-treatment under 5 kbar. On the pre-heated microbeads, almost no graphitization was observed. The spherical shape of the as-separated microbeads was lost even after the heat treatments at low temperatures under 5 kbar. However, the pre-heated microbeads showed the tendency to keep the original spherical shape even after heat treatment at 1900°C.     

Synthesis of iron-dispersed carbons by pressure pyrolysis of divinylbenzene-vinylferrocene copolymer

Versatile carbons with finely dispersed iron were synthesized by pressure pyrolysis of a copolymer prepared from divinylbenzene and vinylferrocene at temperatures below 680? C and pressures of 125 MPa. The pyrolysis conditions of the copolymer were found to influence the final morphology of carbons to give fibrils, spheres and polyhedra. The resulting carbons contained uniformly fine particles of cementite (Fe₃C) which were less than 30 nm in size, whereas the magnetite was dispersed in the carbon matrix by pressure pyrolysis in the presence of water. Highly dispersed cementite in carbon was found to decompose into metallic iron by further heat treatment above 850? C. Porous spherulitic carbons were also synthesized by heat treatment of magnetite containing carbon spherulites.     

Pharmacological properties of lopramine

Pharmacological properties of LOP were compared with those of imipramine(IMP). LOP had little or no effect on electroconvulsive shock and chemoconvulsions in mice, conditioned avoidance response in rats, pain threshold in mice and rats and body temperature in rabbits. LOP, unlike IMP, showed relatively weak effects on general behavior in mice, spontaneous EEG in cats and spontaneous motor activity in mice. LOP prevented oxotremorine-induced hypothermia but not tremor, while IMP antagonized both the responses in mice. In anesthetized dogs, LOP caused a respiratory stimulation and a fall in blood pressure, left ventribular pressure and left ventricular dp/dt without a noticeable effect on heart rate. LOP was less potent than IMP in the depressor and cardiodepressing effects, antispasmogenic activity and in antagonizing the depressor response to acetylcholine. LOP, like IMP, potentiated pressor response to norepinephrine and reduced that to tyramine in anesthetized dogs, but neither antidepressant produced norepinephrine potentiation in isolated guinea-pig vas deferens. Both drugs inhibited spontaneous motility of the jejunum without reducing the gastric motility in anesthetized dogs. These results indicate that, compared with IMP, LOP is characterized by weak general pharmacological activities.     

Synthesis and properties of magnetite-dispersed carbon by pressure pyrolysis of divinylbenzene-vinylferrocene with water

Magnetite-dispersed carbon was synthesized by pressure pyrolysis of the divinylbenzene-vinylferrocene system in the presence of water at 125 MPa below 700°C. Supercritical water influenced the phase separation of oligomers formed during the pyrolysis to give carbons with various morphologies, such as spherulitic, coalescing spherulitic and polyhedral carbon, depending upon the concentration of water. Carbon spherulites from 5 to 10 μm diameter dispersed with magnetite particles (<100 nm) were synthesized by pyrolysis of divinylbenzene-5.1 mol% vinylferrocene and 20.0 wt% water at 550°C and 125 MPa. The specific area of magnetite-dispersed carbon synthesized at 600°C and 125 MPa was 92 m²g⁻¹ after heat treatment at 800°C for 1 h. The specific area of the carbon specimen increased with decreasing pyrolysis temperature of the parent copolymers from 700 to 550°C. The Curie temperature of magnetite-dispersed carbon was 585°C. Magnetite dispersed in the carbon matrix was reduced to wüstite during the further heat treatment in vacuum. The saturation magnetization of magnetite-dispersed carbon was 79% of the theoretical value, and changed in proportion to the concentration of iron in the carbon matrix.     

Alterations of fatty acid metabolism and membrane fluidity in peroxisome-defective mutant ZP102 cells

We investigated lipid composition and FA metabolism in Chinese hamster ovary (CHO-K1) cells and Pex5-mutated CHO-K1 (ZP102) cells to clarify the biochemical bases of peroxisome biogenesis disorders (PBD). ZP102 cells have defective peroxisomes and exhibit impairments of peroxisomal β-oxidation of FA and plasmalogen biosynthesis. In addition, we identified FA metabolic alterations in the synthesis of several classes of lipids in ZP102 cells. The concentration of FFA in ZP102 cells was twice that in CHO-K1 cells, but methyl esters and TAG were decreased in ZP102 cells in comparison with control cells. Also, ceramide monohexoside (CMH) concentration with ZP102 cells was significantly increased compared with the control cells. The FA molecular species, particularly the saturated to unsaturated ratios, of individual lipids also differed between the two cell types. The rate of incorporation of [¹⁴C]-labeled saturated acids into sphingomyelin (SM) and CMH in ZP102 cells was lugher than that in CHO-K1 cells. Lignoceric acid incorporated into cells was predominantly utilized for the synthesis of SM at 24 h after removal of [¹⁴C] lignoceric acid from the culture medium. ZP102 cells showed higher fluorescence anisotropy of 1,3,5-diphenylhexatriene, corresponding to lower membrane mobility than in CHO-K1 cells. In particular, alteration of lipid metabolism by a Pex5 mutation enhanced metabolism of saturated FA and sphingolipids. This may be related to the reduced membrane fluidity of ZP102 cells, which has been implicated in the dysfunction of membrane-linked processes in PBD.     

Physical properties of a new cuprate superconductor Pr2Ba4Cu7O15−δ

We present studies of the thermal, magnetic, and electrical transport properties of reduced polycrystalline Pr₂Ba₄Cu₇O_15−δ (Pr247) showing a superconducting transition at T_c=10-16 K, and compare them with those of as-sintered non-superconducting Pr247. The electrical resistivity in the normal state exhibited T² dependence up to approximately 150 K. A clear specific heat anomaly was observed at T_c for Pr247 reduced in a vacuum for 24 h, proving the bulk nature of the superconducting state. By the reduction treatment, the magnetic ordering temperature T_N of Pr moments decreased from 16 to 11 K, and the entropy associated with the ordering increased, while the effective paramagnetic moments obtained from the DC magnetic susceptibility varied from 2.72 to 3.13μ_B. The sign of Hall coefficient changed from positive to negative with decreasing temperature in the normal state of a superconducting Pr247, while that of the as-sintered one was positive down to 5 K. The electrical resistivity under high magnetic fields was found to exhibit T^α dependence (α=0.08-0.4) at low temperatures. A possibility of superconductivity in the so-called CuO double chains is discussed.     

Synthesis and Characterization of 2,13- and 3,13-Octadecadienals for the Identification of the Sex Pheromone Secreted by a Clearwing Moth

In addition to 2,13- and 3,13-octadecadien-1-ols and their acetates, aldehyde analogs have been identified from lepidopteran species in the family Sesiidae. To establish a reliable analytical method for determining the positions and configurations of the two double bonds in natural pheromone components, all geometric isomers of the 2,13- and 3,13-octadecadienals were synthesized by Dess-Martin oxidation of the corresponding alcohols with limited isomerization of the double bond at the 2- or 3-position. GC-MS analysis of these aldehydes showed isomerization of (Z)-2-, (Z)-3-, and (E)-3-double bonds to an (E)-2-double bond, even with a cool on-column injection. In contrast, HPLC analysis with an ODS column was accomplished without isomerization. The geometric isomers of each dienal eluted in the order ZZ → EZ → ZE → EE. The conjugated 2,13-dienals were detectable in nanogram amounts with a UV detector at 235 nm. Whereas the detection of 3,13-dienals was difficult because of the lack of a chromophore, a highly sensitive analysis was achieved after derivatization with 2,4-dinitrophenylhydrazine. LC-MS with atmospheric pressure chemical ionization showed a strong [M-1]^- at m/z 443 for the derivatives. Based on these analytical data, a pheromone extract of a sesiid moth, Macroscelesia japona, was examined by HPLC and LC-MS, and it was confirmed that the octadecadienal tentatively identified by a previous GC-MS analysis did indeed have the 2E,13Z configuration. Furthermore, field evaluation of four synthetic geometric isomers of the 2,13-dienal revealed specific attraction to a lure with the (2E,13Z)-isomer as a main component.     

Identification of Novel C20 and C22 Trienoic Acids from Arctiid and Geometrid Female Moths that Produce Polyenyl Type II Sex Pheromone Components

Gas chromatography-mass spectrometry (GC-MS) and GC-electroantennographic detection (EAD) analyses of the sex pheromone extract from a wasp moth, Syntomoides imaon (Lepidoptera: Arctiidae: Syntominae), showed that virgin females produced (Z,Z,Z)-3,6,9-henicosatriene and (Z,Z,Z)-1,3,6,9-henicosatetraene with a trace amount of their C(20) analogs. Identification of the chemical structures was facilitated by comparison with authentic standards and the double-bond positions were confirmed by dimethyl disulfide derivatization of monoenes produced by a diimide reduction. In a field test in the Yonaguni-jima Islands, males of the diurnal species were captured in traps baited with a 1:2 mixture of the above-described synthetic C(21) polyenes. Lipids were extracted from the abdominal integument and its associated oenocytes and peripheral fat bodies. Following derivatization, fatty acid methyl esters (FAMEs) were fractionated by HPLC equipped with an ODS column, and methyl (Z,Z,Z)-11,14,17-icosatrienoate and (Z,Z,Z)-13,16,19-docosatrienoate were identified by GC-MS. These novel C(20) and C(22) acid moieties are longer-chain analogs of linolenic acid, (Z,Z,Z)-9,12,15-octadecatrienoic acid. They are presumed to be biosynthetic precursors of the S. imaon pheromone because the C(21) trienyl component might be formed by decarboxylation of the C(22) acid. On the other hand, the C(20) acid, but not the C(22) acid, was found in FAMEs of Ascotis selenaria cretacea (Lepidoptera: Geometridae), which secretes C(19) pheromone components, (Z,Z,Z)-3,6,9-nonadecatriene and the monoepoxy derivative, indicating that different systems of the chain elongation might play an important role in developing species-specific communication systems mediated with polyunsaturated hydrocarbons and/or epoxy derivatives, components of Type II lepidopteran sex pheromones.