Diphenylphosphinothioyl compounds were ortho-lithiated and alkyldiphenyl phosphine sulfides were α-lithiated and the resulting lithio compounds reacted to give the corresponding - and α-substituted products. 相似文献
On DDQ oxidation under anhydrous conditions, hydroxy groups located at α or β position to methoxybenzyl ether groups were readily protected by the intramolecular oxidative formation of acid-sensitive methoxybenzylidene acetals, which were further oxidized to alkali-sensitive hydroxy esters in the presence of H2O. 相似文献
The usual no-cloning theorem implies that two quantum states are identical or orthogonal if we allow a cloning to be on the two quantum states. Here, we investigate a relation between the no-cloning theorem and the projective measurement theory that the results of measurements are either + 1 or − 1. We introduce the Kochen-Specker (KS) theorem with the projective measurement theory. We result in the fact that the two quantum states under consideration cannot be orthogonal if we avoid the KS contradiction. Thus the no-cloning theorem implies that the two quantum states under
consideration are identical in that case. It turns out that the KS theorem with the projective measurement theory says a new version of the no-cloning theorem. Next, we investigate a relation between the no-cloning theorem and the measurement theory based on the truth values that the results of measurements are either + 1 or 0. We return to the usual no-cloning theorem that the two quantum states are identical or orthogonal in the case.
Pancreatic β-cells play a central role in the maintenance glucose homeostasis by secreting insulin, a key hormone that regulates blood glucose levels. Dysfunction of the β-cells and/or a decrease in the β-cell mass are associated closely with the pathogenesis and pathophysiology of diabetes mellitus, a major metabolic disease that is rapidly increasing worldwide. Clarification of the mechanisms of insulin secretion and β-cell fate provides a basis for the understanding of diabetes and its better treatment. In this review, we discuss cell signaling critical for the insulin secretory function based on our recent studies. 相似文献
Isothiocyanates were treated with amino acetal and conc. HCl (0.5 eq.) successively in one-pot to afford 1-substituted imidazole-2-thiones in good yields. 相似文献
A novel organic-inorganic hybrid thermotropic liquid crystal (LC) is developed by the hybridization of an organic amine with a mesogenic core and an acicular anisotropic TiO2 particle through the adsorption of the amino group to the surfaces of the TiO2. The hybrid LC shows nematic phases in wide ranges of temperatures. Variable-temperature small-angle X-ray measurements reveal that the formation of the one-dimensional nematic order of the acicular particles on a submicrometer scale induces thermotropic liquid crystallinity. This technique would lead to induction of dynamic functions in inorganic particles. 相似文献
The mole fractions of hydroxo complexes of titanium(IV) ion in an aqueous solution with 0.10 mol dm(-3) NaClO4 at 25 degrees C have been determined as a function of pH by a newly developed analytical procedure based on UV spectrophotometry, using a metastable homogeneous solution of 1.25 x 10(-4) mol dm(-30 in total concentration of Ti(IV). Also, the total concentration of the hydroxo complexes in equilibrium with Ti(OH)4 solid, or the solubility of Ti(OH)4 solid in an inhomogeneous system, has been obtained by ICP measurement for the solution phase. A combination of these data yielded the absolute concentration of each complex species in equilibrium with Ti(OH)4 solid. Finally, Ti(OH)+3 complex has been assigned to the precursor for the formation of anatase TiO2 nanoparticles transformed from Ti(OH)4 gel from a comparison between the above equilibrium data and a kinetic study on the formation rate of the anatase TiO2 particles in the gel-sol system. 相似文献
Polytetrafluoroethylene samples having different morphology were prepared by radiation induced cross-linking and degradation, and positron annihilation lifetimes were measured to extract information about the vacancy structure from the orth-positronium (o-Ps) component. The o-Ps intensity I3 was inversely correlated with the crystallinity confirming that this component is associated with the amorphous part. The o-Ps lifetime τ3 was distinctly different depending on the phase of the polymer. Below the γ relaxation temperature, the vacancies produced by degradation could be seen from an increase in the τ3 value, but at temperatures between the γ and β relaxations such vacancies became invisible due to the activated segment motion. And above the β relaxation temperature vacancies in the interface between crystalline and amorphous parts appear to affect τ3. The o-Ps intensity did not show stable reproducible results. Accumulation of positive charge can be responsible for it. The results, not only unveiling the not yet well understood behavior of the o-Ps component, demonstrate the uniqueness of the vacancy spectroscopy using o-Ps as a probe. 相似文献
The effects of antioxidants and of an antirad agent mixed in polyethylene and ethylene-propylene copolymer were investigated by means of oxygen consumption and gas evolution. The antioxidants were NBC, Irganox 1010, and DPPD, and the antirad agent was propyl fluoranthene (PFR). A small amount of the antioxidant (0.5 phr) in polymer decreased oxygen consumption by one-half or one-third compared with pure polymer, but the activity was lost with increasing irradiation. The antirad agent also decreased oxygen consumption and it was assumed to act as the energy transfer agent in the polymer matrix. 相似文献
Condensation of a new glycosyl donor, methyl 5-acetamido-4, 7,8,9-tetra-
-acetyl-2,3-dibromo-2,3,5-trideoxy-β-
-2-nonulopyranosonate with various acceptors such as methyl 2,3,4-tri-
-benzyl-α-
-glucopyranoside, cholesterol, methyl 2,4,6-tri-
-bonzyl-α-
-galactopyranoside, and nethyl 5-acetamido-4,7,9-tri-
-acetyl-2,6-anhydro-3,5-dideoxy-
-non-2-enopyranosonate gave only the corresponding β-glycosides. The 3α-bromo group of the glycoaides obtained above was reduced with tributylstannane to the corresponding glycosids, which were deprotected to give the free glycoaides in high yields. 相似文献