Phase relations in NaxCrxTi8−xO16 at 1350 °C and crystal structure of hollandite-like Na2Cr2Ti6O16

Phase relations of rutile, freudenbergite, and hollandite structures were examined in the pseudobinary system NaCrO₂-TiO₂ (i.e., Na_xCr_xTi_8−xO₁₆) at 1350 °C. The hollandite structure was obtained in the composition range 1.7?x?2.0. The symmetry of the samples at room temperature was tetragonal for x=1.7 and 1.75, and monoclinic for x=1.8 and above. Single crystals of monoclinic hollandite Na₂Cr₂Ti₆O₁₆ were grown and the structure refinement has been carried out using an X-ray diffraction technique. The space group was I2/m and cell parameters were a=10.2385(11), b=2.9559(9), c=9.9097(11)Å, and β=90.545(9)° with Z=1. The Na ion distribution in the tunnel was markedly deformed from that in the tetragonal form. It was suggested that Cr/Ti ratios were different between the two framework metal sites.     

Direct capillary gas chromatographic analysis and thermal stability of bile acid esters of glucose

Summary This paper deals for the first time with a direct method for analysis of the α and β anomers of bile acid esters of glucose by capillary gas chromatography (CGC) without the need for a hydrolytic step. The bile acid esters were derivatized to their trimethylsilyl (TMS) ethers, which in turn were chromatographed on a short (7m) metal capillary column chemically coated with a thin (0.15 μm) film of thermostable, non-polar polydimethylsiloxane. Satisfactory CGC separation of the isomeric bile acid esters was achieved on the column; the β anomers eluted before the corresponding α isomers. Particularly noteworthy is that the α anomers are partially isomerized to the corresponding β anomers, and that both anomers are partially decomposed during CGC analysis, demonstrating the chemical specificity and thermal instability of the bile acid esters.     

Preparation and biological activity of 2-[4-(thiazol-2-yl)phenyl]propionic acid derivatives inhibiting cyclooxygenase.

A series of 2-[4-(thiazol-2-yl)phenyl]propionic acids substituted at various positions were prepared by the reaction of diethyl 2-methyl-2-(4-thiocarbamoylphenyl)malonates with alpha-bromoaldehyde diethyl acetals or alpha-haloketones followed by hydrolysis of esters. The inhibition of prostaglandin H synthetase (cyclooxygenase) was assayed by use of an enzyme preparation from guinea pig polymorphonuclear leukocytes. Examination of the structure-activity relationship of these compounds indicated that the substitution pattern with halogens at position 3 (R1) of the benzene ring and a methyl group in position 4 (R2) and/or 5 (R3) of the thiazole ring were favorable for inhibitory activity. The compounds bearing bulky alkyl or polar functional groups at the R2 position were weak inhibitors. The potent inhibitors of cyclooxygenase were tested for their ability to reduce carrageenin-induced inflammation of rat paws. These derivatives had strong anti-inflammatory activity based on their strong inhibition of cyclooxygenase, with some exceptions, including those with a thiomethyl group at R1.     

Epitaxial Growth of Sr x Ba1 − x Nb2O6 Thin Films Prepared from Sol-Gel Process

In this study, we prepared Sr _x Ba_{1 – x} Nb₂O₆ (x = 0.3, 0.5 and 0.7) thin film on 0.75 wt% La doped SrTiO₃ (100) and (110) single crystal substrates. A homogeneous coating solution was prepared with Sr and Ba acetates and Nb(OEt)₅ as raw materials, and acetic acid and diethlene glycol monomethyl ether as solvents. The substrates were coated with the solution by spin coating method. As-coated thin films were heated from 973 to 1273 K in air. The grains of the thin film on La doped SrTiO₃ (100) were pillar shaped and arranged in right angle to each other. On the other hand, the grains of these thin films on La doped SrTiO₃ were pillar shape and arranged in one direction. The crystallographic relationship of the thin film between Sr _x Ba_{1 – x} Nb₂O₆ and substrate that the 130 and 310 direction of the thin film on the substrate were oriented with c-axis in parallel to the substrate surface. On the other hand, (hk0) phase diffractions of Sr _x Ba_{1 – x} Nb₂O₆ thin film on the substrate (110) were investigated in the XRD theta-2theta measurement. It is expected that the Sr _x Ba_{1 – x} Nb₂O₆ (x = 0.3, 0.5 and 0.7) were highly oriented or epitaxial growing on La doped SrTiO₃ (110) single crystal substrate.     

Installation of carbon chain onto 2-cyclohexene-1,4-diol monoacetate

Alkylation of cyclohexenyl monoacetate 1 with R₂Cu(CN)(MgCl)₂ or RMgBr/CuCN (cat.) in Et₂O produced trans 1,2-isomers 4, while arylation and alkenylation of 1 was accomplished with lithium borates 5 and a nickel cat. to afford trans 1,4-isomers 3 selectively. Furthermore, several transformations of the products were carried out to demonstrate synthetic advantages of the present reactions.     

Thalidomide as a nitric oxide synthase inhibitor and its structural development

Thalidomide has been found to exhibit weak nitric oxide synthase (NOS)-inhibitory activity. Structural development studies of thalidomide showed that some N-2,6-dimethylphenylhomophthalimide analogs possess NOS-inhibiting activity.     

Motor protein nano-biomachine powered by self-supplying ATP

A new nano-biomachine has been created from microtubules (MTs) and hetero-bifunctional polymer particles bearing pyruvate kinase, which is propelled on glass surfaces coated with kinesin by use of self-supplying ATP.     

PEGylated polyplex micelles from triblock catiomers with spatially ordered layering of condensed pDNA and buffering units for enhanced intracellular gene delivery

An A-B-C type triblock copolymer, tandemly aligning two types of polycations with different pKa values in a single polymer strand, was developed for the construction of novel polyplex micelles, satisfying a high DNA condensing ability as well as a proton buffering activity directed to elevating gene transfection. The micelle might feature the distinctive three-layered structure, where an inner polyplex layer of condensed pDNA with poly(l-lysine) (pKa approximately 9.4) as the C segment is successively wrapped with an intermediate layer of poly[(3-morpholinopropyl)aspartamide] (B segment) with a comparatively low pKa of approximately 6.2, to provide a buffering effect, and an outer PEG layer (A segment) as a biocompatible palisade.     

Studies on steroids. CCXXXXV. Determination of 5 beta-cholestanoic acids in human urine by gas chromatography-mass spectrometry with negative ion chemical ionization detection

A method for the determination of 3 alpha,7 alpha-dihydroxy-5 beta-cholestanoic acid (DHCA) and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid (THCA) in human urine by gas chromatography (GC) in combination with negative ion chemical ionization (NICI) mass spectrometry is described. Unconjugated, glycine- and taurine-conjugated DHCA and THCA labelled with 18O and 2H were used as internal standards. 5 beta-Cholestanoic acids in urine were extracted with a Sep-Pak C18 cartridge, separated into the unconjugated, glycine- and taurine-conjugated fractions by ion-exchange chromatography on piperidinohydroxypropyl Sephadex LH-20 and, following alkaline hydrolysis of conjugated forms, derivatization into the pentafluorobenzyl ester-dimethylethylsilyl ethers. Subsequent resolution of each fraction into DHCA and THCA was attained by GC on a cross-linked 5% phenylmethylsilicone fused-silica capillary column where 5 beta-cholestanoic acids were monitored with a characteristic carboxylate anion [M-181]- in the NICI mode using isobutane as a reagent gas. The method was applied to separation and determination of 5 beta-cholestanoic acids in urine from a patient with Zellweger syndrome and from healthy volunteers.     

The antiapoptotic effect of low-dose UVB irradiation in NIH3T3 cells involves caspase inhibitions

UVB irradiation is a well-known apoptosis induction factor. However, we have previously found that low doses of UVB irradiation inhibited apoptosis induced by both serum starvation and lack of extracellular matrix, involving a significant inhibition of caspase-3/7 activation. In this study, we report on the relationship between the UVB-induced anti-apoptotic effect and caspase-3/7 inhibition by reactive oxygen species (ROS). The UVB-induced antiapoptotic effect was partially prevented by an antioxidant agent, N-acetylcysteine. A ROS-generating agent, menadione and a pro-oxidant agent, H2O2 also showed an effect that was similar to the UVB-induced antiapoptotic effect, indicating that ROS contributed to the antiapoptotic effect. UVB irradiation significantly suppressed caspase-3/7 activation, which was caused by the inhibition of proteolysis and not by the inhibition of enzymatic activity itself. The prevention of proteolysis was also confirmed by both the following results: one is the inhibition of in vitro caspase-3/7 and -9 activation in cell lysates exposed to UVB in the presence of cytochrome c and dATP, which was caused by the production of ROS, and the other is the inhibition of in vitro caspase-3/7 activation in the presence of active caspase-9. These results showed that the inhibition of the caspase cascade downstream mitochondria by ROS production, leading to a significant inhibition of caspase-3/7 activation, was one of the causes of the antiapoptotic effect by small doses of UVB irradiation.