Potential bile acid metabolites. 24. An efficient synthesis of carboxyl-linked glucosides and their chemical properties

A facile and efficient synthesis of the carboxyl-linked glucosides of bile acids is described. Direct esterification of unprotected bile acids with 2,3,4,6-tetra-O-benzyl-d-glucopyranose in pyridine in the presence of 2-chloro-1,3,5-trinitrobenzene as a coupling agent afforded a mixture of the α- and β-anomers (ca. 1∶3) of the 1-O-acyl-d-glucoside benzyl ethers of bile acids, which was separated effectively on a C₁₈ reversedphase chromatography column (isolated yields of α- and β-anomers are 4–9% and 12–19%, respectively). Subsequent hydrogenolysis of the α- and β-acyl glucoside benzyl ethers on a 10% Pd−C catalyst in acetic acid/methanol/EtOAc (1∶2∶2, by vol) at 35°C under atmospheric pressure gave the corresponding free esters in good yields (79–89%). Chemical specificities such as facile hydrolysis and transesterification of the acyl glucosides in various solvents were also discussed.     

日本第一台商用多种固体流化床（MSFB）锅炉的设计和运行经验

0 引言近年来,在日本营造燃用低质固体燃料的锅炉日益增多,其中主要集中在循环流化床(CFB)锅炉上,这是因为它具有:1)广泛的燃料适应性;2)低的 NO_x 和 SO_2 污染排放。1986年三井公司建造了日本第一台商用 MSFB 锅炉,它被用作 Kuraray 化纤公司的自备动力装置。在此锅炉的设计与运行之前,作者利用试验装置研究了 MSFB 密相床的特性,以保证其性能和运行稳定性。此外,作者还研究了 MSFB 中所采用的固体循环系统在增加燃烧稳定     

Formation of novel polymeric nanoparticles

We have found that not only block copolymers but also ionomers can self-assemble in a selective solvent to form surfactant-free nanoparticles. The self-assembly can be induced by chemical reaction, polymer-polymer complexation, and microphase inversion in addition to the temperature. A recently developed microwave method for the preparation of uniform surfactant-free polymeric nanoparticles is also reviewed. Our results have revealed that for a given dispersion, the particle surface area occupied per stabilizer (surfactant, polymer chains, and ionic groups) is close to a constant.     

Interaction between dietary protein and fat in triglyceride metabolism in the rat: Effects of soy protein and menhaden oil

The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids in the regulation of triglyceridemia in rats. Male Sprague-Dawley rats (n=56) were subjected to 28-d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14% w/w): (i) casein-menhaden oil, (ii) casein-beef tallow, (iii) soy protein-menhaden oil, and (iv) soy protein-beef tallow. Significant protein-lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect on post-heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil.     

Design of small-area multi-bit antifuse-type 1 kbit OTP memory

A multi-bit antifuse-type one-time programmable (OTP) memory is designed, which has a smaller area and a shorter programming time compared with the conventional single-bit antifuse-type OTP memory. While the conventional antifuse-type OTP memory can store a bit per cell, a proposed OTP memory can store two consecutive bits per cell through a data compression technique. The 1 kbit OTP memory designed with Magnachip 0.18 μm CMOS (complementary metal-oxide semiconductor) process is 34% smaller than the conventional single-bit antifuse-type OTP memory since the sizes of cell array and row decoder are reduced. And the programming time of the proposed OTP memory is nearly 50% smaller than that of the conventional counterpart since two consecutive bytes can be compressed and programmed into eight OTP cells at once. The layout area is 214 μm × 327 μm, and the read current is simulated to be 30.4 μA. Foundation item: Project supported by the 2nd Stage of Brain Korea; Project supported by the Korea Research Foundation     

Associations between apolipoprotein E genotype and circulating F<Subscript>2</Subscript>-isoprostane levels in humans

Apolipoprotein E (apoE), an important determinant of plasma lipoprotein metabolism, has three common alleles (ε2, ε3, and ε4). Population studies have shown that the risk of diseases characterized by oxidative damage, such as coronary heart disease and Alzheimer’s disease, is significantly higher in ɛ4 carriers. We evaluated the association between apoE genotypes and plasma F₂-isoprostane levels, an index of lipid peroxidation, in humans. Two hundred seventy-four healthy subjects (104 males, 170 females; 46.9±13.0 yr; 200 whites, 74 blacks; 81 nonsmokers, 64 passive smokers, and 129 active smokers) recruited for a randomized clinical antioxidant intervention trial were included in this analysis. ApoE genotype was determined by PCR and restriction enzyme digestion. Free plasma F₂-isoprostane was measured by GC-MS. Genotype groups were compared using multiple regression analysis with adjustment for sex, age, race, smoking status, body mass index, plasma ascorbic acid, and β-carotene. Subjects with ε3/ε4 and ε4/ε4 genotype (ε4-carriers) and with ε2/ε3 and ε3/ε3 (non-ε4-carriers) were pooled for analysis. In subjects with high cholesterol levels (total cholesterol above 200 mg/dl), plasma F₂-isoprostane levels were 29% higher in ε4 carriers than in non-ε4-carriers (P=0.0056). High-cholesterol subjects that are ε4 carriers have significantly higher levels of lipid peroxidation as assessed by circulating F₂-isoprostane levels.     

HEAT TREATMENT STRENGTHENING EFFECTS OF RARE EARTHS ON Mg—9Al ALLOY

Mg-9Al-xRE magnesium alloys were studied, where, x is 0, 0.4. 0.8. 1.2 and 1.6% (in weight percent, wt%), respectively. Influence of rare earths (RE) on microstructure and strength in both T4 (solute heat treatment) and T6 (solute heat treatment and artificial ageing treatment) were investigated. Strength of specimen was tested at ambient temperature. The micro structure was analyzed by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction analysis. RE additions improved T4 tensile strength of the treated alloys. Small addition (0.4wt%) of RE greatly improved the strength of ageing treated (T6) Mg-9Al alloy, but further additions caused decreasing.     

INFLUENCE OF ALLOYING ELEMENTS ON HYDROGEN DIFFUSION USING SCM-DV-Xα

The influence of alloy composition (Ti,Mn,TiN) on hydrogen diffusion in Fe was studied in detail using SCM-DV-Xα method.The voltage barriers were obtained via calculation on Fe clusters containing the alloy elements such as Ti,Mn as well as the chemical compound TiN respectively.The results showed that Ti element produced deep trap in Fe,decreasing the diffusion coefficient of hydrogen elements，Mn element did not produce deep trap in Fe,decreasing the diffusion coefficient slightly and TiN in Fe produced very deep “trap” decreasing the diffusion coefficient obviously.The calculation results were in agreement with experiment results.     

MICROSTRUCTURAL EVOLUTION OF HIGHLY UNDERCOOLED EUTECTIC Ni78.6Si21.4 ALLOY

A large undercooling level up to 550K （0.386Te） was achieved in eutectic Ni78.6Si21.4melt by the combination of molten-glass and cyclic superheating. A microcrystaUine structure is obtained at large undercooling. Surprisingly, the morphology of ct（Ni） phase transits from the non-faceted phaseto faceted phase at large undercooling of 390K. Based on the classical nucleation theory and transient nucleation theory, the process of microstructure evolution and competitive nucleation was analyzed, and the refinement of crystal structure is determined by the high nucleation rate under large undercooling.     

THE EFFECTS OF SPUTTERING POWER ON STRUCTURE AND ELECTRICAL PROPERTIES OF Cu FILMS

1. IntroductionCu filnls are very pron1isillg for electronic devices because of both high electromigrationresista11ce alld high electrical conductivity['--']. For a sputter-deposited film, base pressure,deposition rate, substrate temperature and energetic…