Background: Coffee is widely consumed around the world. In Japan, it is a type of "Shikohin" (consumed for flavor, not nutrition). Several medical studies have reported the beneficial effects of coffee consumption, whereas others suggest that these beneficial effects on psychological aspects are marginal.
View Article and Find Full Text PDFBackground: This study aimed to determine whether individual differences in resilience interacted with those in alcohol consumption habits in situations involving exposure to psychosocial stressors (Trier Social Stress Test-Online; TSST-OL). Additionally, we investigated whether individuals exhibiting resilience in their psychological scale scores showed biological responses that could be interpreted as resilience in stressful situations, such as the TSST-OL. We hypothesized that there would be no association between drinking habits and stress responses in the high-resilience group.
View Article and Find Full Text PDFOne-pot reactions reduce reagent amounts and circumvent process treatments, such as work-up and purifications in multi-step reactions. In this study, we achieved the formal total synthesis of riccardin C through a one-pot reaction by simultaneously linking four units through two Sonogashira coupling reactions and one Suzuki coupling reaction, followed by reduction and deprotection. Thus, this one-pot method comprised five steps and did not require the purification of intermediate reaction mixtures, which saves resources, such as reagents and solvents, and expedites the work process.
View Article and Find Full Text PDFThe obligate intracellular bacterium is the major causative agent of bacterial sexually transmitted diseases worldwide. In infected cells, the ceramide transport protein (CERT) is recruited to inclusions, where replicates using host-synthesized ceramide. The ceramide is converted to sphingomyelin (SM) by a chlamydial infection-dependent SM synthesis (cidSM-synthesis) pathway, which occurs even in the absence of the SM synthases (SMS)-1 and -2 of host cells.
View Article and Find Full Text PDFWe have found that the etherification of silyl-protected secondary alcohols proceeds smoothly in the presence of strontium metal using silyl chloride instead of the expensive, yet more reactive, and commonly used silyl triflate. The reaction occurred almost completely with various alcohols.
View Article and Find Full Text PDFHydrogenation of nitriles to primary amines with heterogeneous catalysts under liquid-phase continuous-flow conditions is described. Newly developed polysilane/SiO-supported Pd was found to be an effective catalyst and various nitriles were converted into primary amine salts in almost quantitative yields under mild reaction conditions. Interestingly, a complex mixture was obtained under batch conditions.
View Article and Find Full Text PDFSome individuals recover quickly from stressful events, while others do not; this suggests that there are individual differences in stress resilience. Previous studies in rats have shown that an animal's ability to extinguish conditioned fear can predict their stress resilience. In the present study, we investigated whether rats who are resilient or vulnerable to fear conditioning would consistently show resilient or vulnerable behaviors in other behavioral tests.
View Article and Find Full Text PDF"Retrieval-induced forgetting" in rats was evaluated using a modified spontaneous object recognition test. The test consisted of a sample phase, retrieval or interference phase, and a test phase with 60-min delay period inserted between the phases. Rats were randomly assigned to one of three groups (control, retrieval and interference) and allowed to explore the field in which two different objects (A, B) were placed in the sample phase.
View Article and Find Full Text PDFZn(OH)2-catalyzed allylation reactions of aldehydes with allylboronates in aqueous media have been developed. In contrast to conventional allylboration reactions of aldehydes in organic solvents, the α-addition products were obtained exclusively. A catalytic cycle in which the allylzinc species was generated through a B-to-Zn exchange process is proposed and kinetic studies were performed.
View Article and Find Full Text PDFIn response to Berkeš's report revising the stereochemistry of HPA-12, an important ceramide-trafficking inhibitor that was discovered and synthesized and its stereochemistry determined in 2001, the synthesis and the stereochemistry were reinvestigated. A large-scale synthetic method for HPA-12 based on a Zn-catalyzed asymmetric Mannich-type reaction in water was developed. Single crystals of HPA-12 for X-ray crystallographic analysis were obtained from ethyl propionate/n-hexane, and the stereochemistry was definitely determined to be 1R,3S, consistent with Berkeš's revised structure.
View Article and Find Full Text PDFAsymmetric Michael reactions and enantioselective protonations between enones and thiols were catalyzed by a Sc(OTf)(3)-chiral 2,2'-bipyridine complex in water. The remarkable governing of the enantioselectivity for simple introduction of protons despite their abnormally high mobility in water may provide us with new synthetic opportunities as well as significant chemical advances.
View Article and Find Full Text PDFThe world constructed by self-organization of some amphiphils was discussed on the basis of micelle formation, vesicle formation, and oriented-nano-wire formation. First, the micelle formation of a both water- and oil- soluble surfactant, Aerosol OT, was discussed. Solution states of micelles and monomer were discussed on the basis of thermodinamic and NMR spectroscopic analyses of micelle formation.
View Article and Find Full Text PDFSeveral bismuth-catalyzed synthetic reactions, which proceed well in aqueous media, are discussed. Due to increasing demand of water as a solvent in organic synthesis, catalysts that can be used in aqueous media are becoming more and more important. Although bismuth Lewis acids are not very stable in water, it has been revealed that they can be stabilized by basic ligands.
View Article and Find Full Text PDFAsymmetric Michael reactions of thiols with enones were catalyzed by a Sc(OTf)(3)-chiral bipyridine complex at room temperature in water without using any organic solvents, to afford the desired sulfides in high yields with high enantioselectivities.
View Article and Find Full Text PDFChem Commun (Camb)
February 2010
Zn(OH)(2)-catalyzed allylation reactions of allylboronates with aldehydes proceeded smoothly in aqueous media; when alpha-substituted allylboronates were employed, the alpha-addition products were obtained exclusively, and syn-adducts were formed selectively in most cases; the use of Zn(OH)(2) with dmp (ligand) in aqueous media is the key to these reactions.
View Article and Find Full Text PDFGolden capillaries: A gold-immobilized capillary column reactor allows oxidation of alcohols to carbonyl compounds using molecular oxygen. These capillary columns (see picture) can be used for at least four days without loss of activity.
View Article and Find Full Text PDFWe have discovered the unprecedented catalytic use of In(0) for catalytic C-C bond transformations. Remarkably, these general catalytic allylations of ketones proceeded smoothly in water as a sole solvent under mild conditions, and water proved to be essential for these reactions. Both the displayed substrate scope and the functional group tolerance were excellent.
View Article and Find Full Text PDFThe molecular mechanism by which nascent HDL forms via the interaction of apolipoprotein A-I (apoA-I) and transmembrane ABCA1 is poorly understood. Here, because ABCA1 has been reported to localize to acidic intracellular compartments, including the Golgi and endosome, we studied the interaction of apoA-I with model membranes under acidic conditions. Pure phosphatidylcholine liposomes were persistent against apoA-I at pH levels above 5.
View Article and Find Full Text PDFThe mechanism of vesicle-to-micelle or micelle-to-vesicle transition was studied in order to control sizes and fluidities of vesicles during periods of preparation. Dependence of particle sizes measured by quasi-elastic light scattering, turbidities, fluidity parameters monitored by ESR spectroscopy, and morphological changes of mixed aggregates of egg yolk phosphatidylcholine (EPC) and a detergent (octylglucoside (OG) or sodium cholate (Na-chol)) on detergent concentration provided a model of vesicle destruction. It possessed three phase transition points, and proceeded in a stepwise fashion: vesicles, small particles containing large amounts of detergents (SUV(*)), intermediate structures, and mixed micelles.
View Article and Find Full Text PDFA new method of immobilizing Pd catalysts on the channel wall of a capillary by using polysilane with metal oxide has been developed, and applied to hydrogenation reactions.
View Article and Find Full Text PDFOne of the most significant organic transformations in catalyst technology is the selective oxidation of alcohols. The acceleration of catalyst discovery in this field contributes to the economic and environmental impact in the production of useful materials. Heterogeneous catalysts combined with environmentally benign oxidants, such as molecular oxygen and hydrogen peroxide, are major challenges of exploratory research in the oxidation of alcohols.
View Article and Find Full Text PDFA novel organic-inorganic hybrid ruthenium (HB Ru) catalyst for the oxidation of alcohols with molecular oxygen has been developed. The catalyst was prepared from a polystyrene-based copolymer, which includes a trimethoxysilyl functionality, and dichlorotris(triphenylphosphine)ruthenium, [RuCl2(PPh3)3], as the metal source. A sol-gel process was employed for heterogenization of the catalyst.
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