Preparation of ethyl 2-aryl 2,3-alkadienoates via palladium-catalyzed selective cross-coupling reactions

Pd-catalyzed cross-coupling reactions of aryl iodides containing not only an electron-donating group but also an electron-withdrawing group on the aryl ring with organoindium reagents generated in situ from indium and ethyl 4-bromo-2-alkynoates produced selectively ethyl 2-aryl-2,3-alkadienoates in good yield.     

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??In this paper, we prove the existence and uniqueness of solutions for reflected backward stochastic differential equations driven by a Levy process, in which the reflecting barriers are just right continuous with left limits whose jumps are arbitrary. To derive the above results, the monotonic limit theorem of Backward SDE associated with Levy process is established.     

Understanding the Structural Differences between Spherical and Rod‐Shaped Human Insulin Nanoparticles Produced by Supercritical Fluids Precipitation

In this study, the thermal denaturation mechanism and secondary structures of two types of human insulin nanoparticles produced by a process of solution‐enhanced dispersion by supercritical fluids using dimethyl sulfoxide (DMSO) and ethanol (EtOH) solutions of insulin are investigated using spectroscopic approaches and molecular dynamics calculations. First, the temperature‐dependent IR spectra of spherical and rod‐shaped insulin nanoparticles prepared from DMSO and EtOH solution, respectively, are analyzed using principal component analysis (PCA) and 2D correlation spectroscopy to obtain a deeper understanding of the molecular structures and thermal behavior of the two insulin particle shapes. All‐atom molecular dynamics (AAMD) calculations are performed to investigate the influence of the solvent molecules on the production of the insulin nanoparticles and to elucidate the geometric differences between the two types of nanoparticles. The results of the PCA, the 2D correlation spectroscopic analysis, and the AAMD calculations clearly reveal that the thermal denaturation mechanisms and the degrees of hydrogen bonding in the spherical and rod‐shaped insulin nanoparticles are different. The polarity of the solvent might not alter the structure or function of the insulin produced, but the solvent polarity does influence the synthesis of different shapes of insulin nanoparticles.     

Interphotoreceptor Retinoid‐Binding Protein Protects Retinoids from Photodegradation

Retinol degrades rapidly in light into a variety of photoproducts. It is remarkable that visual cycle retinoids can evade photodegradation as they are exchanged between the photoreceptors, retinal pigment epithelium and Müller glia. Within the interphotoreceptor matrix, all‐trans retinol, 11‐cis retinol and retinal are bound by interphotoreceptor retinoid‐binding protein (IRBP). Apart from its role in retinoid trafficking and targeting, could IRBP have a photoprotective function? HPLC was used to evaluate the ability of IRBP to protect all‐trans and 11‐cis retinols from photodegradation when exposed to incandescent light (0 to 8842 μW cm^?2); time periods of 0–60 min, and bIRBP: retinol molar ratios of 1:1 to 1:5. bIRBP afforded a significant prevention of both all‐trans and 11‐cis retinol to rapid photodegradation. The effect was significant over the entire light intensity range tested, and extended to the bIRBP: retinol ratio 1:5. In view of the continual exposure of the retina to light, and the high oxidative stress in the outer retina, our results suggest IRBP may have an important protective role in the visual cycle by reducing photodegradation of all‐trans and 11‐cis retinols. This role of IRBP is particularly relevant in the high flux conditions of the cone visual cycle.     

A note on the doubly reflected backward stochastic differential equations driven by a Lévy process

In this note, we study the doubly reflected backward stochastic differential equations driven by Teugels martingales associated with a Lévy process (DRBSDELs for short). In our framework, the reflecting barriers are allowed to have general jumps. Under the Mokobodski condition, by means of the Snell envelope theory as well as the fixed point theory, we show the existence and uniqueness of the solution of the DRBSDELs. Some known results are generalized.     

铀-4,5-二溴苯基萤光酮-吐温-60显色体系的分光光度法研究

铀的高灵敏高选择性的光度法尚少见。最近有人合成过二溴苯基萤光酮(下简称Br-PF),但未见用于测定铀的报导。为此,本文研究了在吐温-60存在下用Br-PF测定铀的条件,结果表明,本法的灵敏度较高(ε=1.79×10⁵),是迄今为止铀最灵敏的显色反应(见表1)。采用三辛胺(TOA)萃取分离铀,并用于岩矿中铀的测定。     

Supercritical Fluid Chromatographic Separations of PAHs Using Methanol Modified Carbon Dioxide Mobile Phase.

An analytical method is described for separating polyaromatic hydrocarbons using modified supercritical carbon dioxide and pure carbon dioxide. The effects of adding methanol in supercritical carbon dioxide mobile phase were studied. The modifier, methanol affected especially in the retentions of polyaromatic hydrocarbons.     

Weak convergence to Rosenblatt sheet

We study the problem of the approximation in law of the Rosenblatt sheet. We prove the convergence in law of two families of process to the Rosenblatt sheet: the first one is constructed from a Poisson process in the plane and the second one is based on random walks.     

Complete Convergence of Weighted Sums for Arrays of Rowwise $m$-Negatively Associated Random Variables

In this paper, we discuss the complete convergence of weighted sums for arrays of rowwise $m$-negatively associated random variables. By applying moment inequality and truncation methods, the sufficient conditions of complete convergence of weighted sums for arrays of rowwise $m$-negatively associated random variables are established. These results generalize and complement some known conclusions.     

Synthesis of 2-alkyl- and aryl-3-ethoxycarbonyl-2,5-dihydrofurans through gold-catalyzed intramolecular hydroalkoxylation

Treatment of a wide range of functionalized hydroxyallenic esters with 5 mol % Ph(3)PAuCl and 5 mol % AgOTf in CH(2)Cl(2) at 25 °C for 1 h produced selectively 2-alkyl- and aryl-3-ethoxycarbonyl-2,5-dihydrofurans in good to excellent yield through intramolecular hydroalkoxylation by a 5-endo mode.