Conjugate Addition of Phosphine-Complexed Organocopper Reagents to α,β-Unsaturated Ketones

Organocopper reagents formed from equimolar amounts of copper(I) iodide and organolithiums and 2 to 3 equiv of tri-n-butylphosphine undergo smooth reaction with α,β-unsaturated ketones, and after aqueous quenching afford β-substituted ketones in high yields. This method is economical (enone/organolithium=1:1.05 to 1:1.25) and applicable to a wide variety of entering groups and enone substrates, and compares well with the existing procedures.     

Synthesis of triacylglycerol by lipase in phosphatidylcholine reverse micellar system

Triacylglycerols were synthesized from 1,2-diacylglycerol and fatty acids by lipase entrapped in phosphatidylcholine reverse micelles in n-hexane. In the reaction system without reverse micelles, however, 1,2-diacylglycerol was hydrolyzed into 2-monoacylglycerol and fatty acid, and triacylglycerol was not synthesized. The maximum activity of synthetic reaction was obtained at Wo=10 (Wo=mol water/mol surfactant), which was the water content of this reverse micellar system. Though the optimal pH of theR. delemar lipase reaction is about pH 5.6 in a bulk water system, the enzyme was active for triacylglycerol synthesis at pH’s from 5 to 9 in the reverse micellar system. For the synthesis of triacylglycerols, lauric, myristic, palmitic, stearic, oleic and arachidic acids were effectively used as the fatty acid substrate. 2-Monoacylglycerol was also effective as a substrate of triacylglycerol synthesis. Furthermore, 1,2-diacylglycerol could be replaced by several kinds of aliphatic alcohols as fatty acid acceptors in the reverse micellar system. In this case, those alcohols with chain length more than 4 carbons were effectively used for ester formation.     

Token reinforcements in the shaping of children's mealtime behaviour.

Shaping and subsequent extinction of acceptable mealtime behavior through selective token reinforcement was attempted with institutionalized, emotionally disturbed children. Results suggested the feasibility of utilizing individual judgements by staff personnel in behavior shaping and dispensing of reinforcements. In addition, control of mealtime behavior in some children was seen to vary as a function of the presentation or withholding of tokens. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Presence of Apolipoprotein C-III Attenuates Apolipoprotein E-Mediated Cellular Uptake of Cholesterol-Containing Lipid Particles by HepG2 Cells

Apolipoprotein C-III (apoC-III) decreases the apolipoprotein E (apoE)-mediated uptake of lipoprotein remnants by the liver, and a high plasma concentration of apoC-III in VLDL is associated with hypertriglyceridemia and the risk of coronary heart disease. In this study, we prepared lipid emulsions containing triolein, phosphatidylcholine and cholesterol as model particles of lipoproteins, and examined the roles of apoC-III in apoE-mediated uptake of emulsions by HepG2 cells. Cholesterol in emulsion particles enhanced the apoE-mediated uptake via heparan sulfate proteoglycan and LDL receptor-related protein pathways. The amount of apoE bound to emulsion particles was increased by the presence of cholesterol at the particle surface, whereas cholesterol had no effect on the binding amount of apoC-III. Surface cholesterol alleviated the inhibitory effect of apoC-III on apoE incorporation into the emulsion surface. However, ApoC-III almost completely inhibited the apoE-mediated uptake of cholesterol-containing emulsions despite sufficient binding of apoE to emulsions. These findings suggest that apoC-III attenuates the binding of apoE to the lipoprotein surface and apoE-mediated cellular uptake of lipoprotein remnants. Furthermore, cholesterol may affect these functions of apoC-III and apoE involved in the clearance of lipoprotein remnants.     

Effect of DC and AC electric fields on crack healing behavior in 8 mol% yttria-stabilized cubic zirconia polycrystal

The effect of the flash event (FE) on microcrack healing behavior in 8 mol% yttria-stabilized zirconia was examined at healing temperatures of 1040 and 1230°C under the direct and alternating (DC and AC) electric fields. The crack healing behavior changed depending on the factors of the electric field, healing temperature, and crack length. Although the crack healing proceeded with the temperature, the healing rate increased with the crack length, suggesting that the external energy stored as crack surface energy would provide a driving force for the crack healing. Although the crack healing occurs even under the static annealing without the electric field, the healing rate was accelerated by FE significantly more under the AC field than under the DC field. The microcracks with a length of ≈20 μm were fully healed at 1230°C only for 10 min by the FE treatment under the AC field, and the flash healing behavior was four times faster than that of the static annealing. These results suggest that the enhanced healing behavior cannot be explained only by thermal effects, and the accelerated diffusivity caused additionally by nonthermal effect under FE might contribute to the enhanced healing behavior, especially in the AC electric field.     

Flash self-joining of Y-TZP ceramics assisted with an AC electric field

In this study, flash joining experiments were conducted using an AC field on 3 mol% Y₂O₃-stabilized tetragonal ZrO₂ polycrystal (Y-TZP) bodies. Furthermore, the necessary conditions to obtain an almost complete self-joining of Y-TZP bodies were clarified. The specimens were successfully joined by applying an AC field at 60 mA mm⁻² for 80 s at a furnace temperature of 1000°C, thus resulting in a successfully joined specimen with 92% of the flexural strength of the as-sintered Y-TZP body. Almost complete self-joining of Y-TZP was achieved at current densities above 30 mA mm⁻², and input energy densities of >24 J mm⁻³. Both the input energy density and electric current were critical factors for producing the reliable joining of ceramics.     

Thermal decomposition of carbon-rich polymer-derived silicon carbonitrides leading to ceramics with high specific surface area and tunable micro- and mesoporosity

Herein we report on the thermal decomposition of SiCN polymer-derived ceramics leading to materials with high specific surface area and defined pore sizes. The ceramics were obtained by means of pyrolysis of a carbon-rich poly(diphenylsilylcarbodiimide) precursor and by varying the thermolysis parameters, namely temperature, annealing time and using additional annealing steps. The thermal decomposition of SiCN ceramics is correlated with the carbothermal reaction of amorphous silicon nitride phase with excess carbon and this detrimental event leads to high specific surface area up to 568 m² g⁻¹ and micro- and mesopores formation in these materials. High-resolution TEM investigations have confirmed that the pores are embedded only in the carbon phase. Moreover, the relationship between the pore sizes and the organization of free carbon phase is discussed.     

Influence of surface finish processing on contact voltage drop in Cu/C electrical sliding contacts

A sliding contact is normally used to supply current to a rotating or moving object. The surface film formed on the sliding surface is important for ensuring reliability and long life. In the present study, the effects of preoperation conditions and initial surface condition are investigated. We examined the relation between sliding speed and chemical treatment for electrical sliding contact action. The initial surface condition and preoperation conditions greatly influence the contact voltage drop that occurs during operation. It is shown that stability of sliding contact can be achieved by appropriate surface treatment and preoperation conditions. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.