Quasiclassical trajectory study of the postquenching dynamics of OH A 2Σ+ by H2/D2 on a global potential energy surface

We report full-dimensional, electronically adiabatic potential energy surfaces (PESs) for the ground state (1A(')) and excited state (2A(')) of OH(3). The PESs are permutationally invariant fits to roughly 23,000 electronic energies (MRCI + Q/aVTZ). Classical trajectory calculations of the postquenching dynamics of OH A (2)Σ(+) are carried out on the 1A(') PES for H(2) and D(2), at previously identified conical intersections (CoIs) [B. C. Hoffman and D. R. Yarkony, J. Chem. Phys. 113, 10091 (2000)]. The initial momenta are sampled fully and partially microcanonically, corresponding to "adiabatic" and "diabatic" models of the dynamics, respectively. Branching ratios of reactive to nonreactive channels from separate C(2v), C(∞v), and C(s) symmetries of CoIs are calculated, as are final rovibrational state distributions of OH and H(2) products. The rovibrational distributions of the OH and D(2) products, the D/H-atom translational energy distribution are calculated and compared to experimental ones. Agreement for these observable quantities is good. The branching between reactive and nonreactive quenching is sensitive to the momenta sampling; very good agreement with experiment is obtained using the diabatic sampling but not with the adiabatic sampling. The vibrational state distributions of H(2)O and HOD (although not measured by experiment) are also presented.     

Mild and Efficient Solvent‐Free Friedel–Crafts Acylation of Reserpine

The first mild, efficient, solvent‐free Friedel–Crafts acylation of reserpine has been developed, which resulted in the synthesis of 10‐ and 12‐acylated homologues in high overall yields.     

Synthesis,Crystal Structure and Cytotoxicity Evaluation of 2-Phenoxy-4H-spiro{naphtho[2,3-e][1,4,2] oxazaphosphinane-5,10-dione,1'-cyclohexane} 2-Oxide

1 INTRODUCTION The quinone structure is common in numerous natural products that are associated with antitumor, antibacterial, antimalarial, and antifungal activities[1]. A variety of heterocyclic quinones containing dif- ferent heteroatom substituents could exhibit such activities through different actions and sometimes even improve the activities[2～5]. On the other hand, organophosphorus compounds continue to receive widespread attention due to their ubiquity in biological systems[6, 7]…     

Bioassay-guided isolation of antibacterial constituents from Diospyros lotus roots

The aim of this study was to explore the extract/fractions and compounds of Diospyros lotus against various Gram-positive and Gram-negative bacteria strain. The results showed marked susceptibility of extract and its fractions against test pathogens. Among them, chloroform fraction was most dominant and effective against all tested bacteria. The chloroform fraction was subjected to column chromatography which led to the isolation of lupeol (1), 7-methyljuglone (2), β-sitosterol (3), stigmasterol (4), betulinic acid (5), diospyrin (6) and 8-hydroxyisodiospyrin (7). Among the isolated compounds, betulinic acid (5) showed significant activity against most of the tested pathogen. In conclusion, our study validated the traditional uses of the plant in the treatment of infectious diseases which was also strongly supported by the isolated compound, betulinic acid (5).     

Formulation and evaluation of gel containing nanostructured lipid carriers of tretinoin–Epi-β-CD binary complex for topical delivery

The objective of present research work was to formulate and evaluate topical gel containing tretinoin–cyclodextrin (CD) binary complex loaded into nanostructured lipid carriers (NLCs). Use of cyclodextrin and nanolipid carrier together in a system produced a synergistic effect by increasing the drug release and skin permeation, thus improving the overall therapeutic effect. Two different cyclodextrins i.e. β-CD and its water soluble polymeric derivative epichlorohydrin-β-cyclodextrin (EPI-β-CD) were used to obtain binary inclusion complex of drug-cyclodextrin (D-CD) systems by two different techniques (kneading and co-evaporation). The prepared solid complexes were characterized by FTIR, DSC, XRD etc. and the best system was selected for loading into nanolipid carriers. NLC comprising glyceryl mono stearate (GMS) and oleic acid were obtained by slightly modified emulsification evaporation method. Four different formulations of NLCs were suitability characterized for particle size, zeta potential, entrapment efficiency, drug loading and drug release. EPI-β-CD was found to be more effective than β-CD in enhancing solubility and dissolution properties of tretinoin. The most effective NLC formulation was incorporated into carbopol hydrogel which showed better permeation properties than that of the reference gel (0.1%).     

Pistagremic acid,a novel β-secretase enzyme (BACE1) inhibitor from Pistacia integerrima Stewart

A new triterpenic compound named pistagremic acid (PA) was once again isolated from Pistaciaintegerrima. The β-secretase inhibition study was carried out. Compound PA was found significantly active against β-secretase enzyme (BACE1) with IC₅₀ value of 350 ± 2 nM in comparison to the standard inhibitors [Asn670, Sta671, Val672]-amyloid-β/A4 precursor protein 770 fragment 662–675 (IC₅₀ = 290.71 ± 1 nM). The selectivity of this compound was also evaluated against the acetylcholinesterase and butyrylcholinesterase enzymes. Interestingly compound PA was found to be inactive against them and showed selectivity towards β-secretase enzyme (BACE1).     

液相色谱法分离制备环烯醚萜化合物

液相制备色谱;分离;液相色谱法分离制备环烯醚萜化合物     

Liquid-liquid extraction and recovery of indium using Cyanex 923

The extraction of In(III) from HCl, H₂SO₄, and HNO₃ media using a 0.20 mol l⁻¹ Cyanex 923 solution in toluene is investigated. In(III) is quantitatively extracted over a fairly wide range of HCl molarity while from H₂SO₄ and HNO₃ media the extraction is quantitative at low acid concentration. The extracted metal ion has been recovered by stripping with 1.0 mol l⁻¹ H₂SO₄. The stoichiometry of the In(III): Cyanex 923 complex is observed to be 1:2. The extraction of In(III) is insignificantly changed in diluents namely toluene, n-hexane, kerosene (160-200 °C), cyclohexane, and xylene having more or less the same dielectric constants, whereas, it decreases with increasing polarity of diluents such as cyclohexanone and chloroform. The extractant is stable towards prolonged acid contact and there is a negligible loss in its extraction efficiency even after recycling for 20 times. The extraction behavior of some commonly associated metal ions namely V(IV), Ti(IV), Al(III), Cr(III), Fe(III), Ga(III), Sb(III), Tl(III), Mn(II), Fe(II), Cu(II), Zn(II), Cd(II), Pb(II), and Tl(I) has also been investigated. Based on the partition data the conditions have been identified for attaining some binary separations of In(III). These conditions are extended for the recovery of pure indium from zinc blend, zinc plating mud, and galena. The recovery of the metal ions is around 95% with purity approximately 99%.     

Noncommutativity, Generalized Uncertainty Principle and FRW Cosmology

We consider the effects of noncommutativity and the generalized uncertainty principle on the FRW cosmology with a scalar field. We show that, the cosmological constant problem and removability of initial curvature singularity find natural solutions in this scenarios.     

多原子反应体系的高精度拟合势能面

本文介绍了近几年来我们组构建多原子反应体系的高精度拟合势能面的进展。我们基于神经网络(NN)方法,成功构建了多原子气相分子体系和气相分子在金属表面解离的一系列势能面。这些势能面的拟合精度相当高,并且经过了严格的量子动力学测试,能广泛应用到动力学研究中。我们还提出了一种新的置换不变势能面的拟合方法,即基本不变量神经网络方法(FI-NN)。基本不变量的使用极大地减少了神经网络输入层多项式的个数,有效提高了势能面的计算速度。