A new highly hydroxylated triterpene from Salvia atropatana Bunge

One new triterpenoid olean-18-ene-1β, 2α, 3β-triol (1) along with four known compounds were isolated from the chloroform extract of the aerial part of Salvia atropatana Bunge. The known compounds were two flavonoids, 5-hydroxy-7,4'-dimethoxyflavone (2) and 5-hydroxy-6,7,4'-trimethoxyflavone (3), an abietane-type diterpene namely taxodione (4) and a phytosterol namely γ -sitosterol (5). The structure of (1) was elucidated by comprehensive spectroscopic analysis including electron ionization-mass spectra (EI-MS), (1)H NMR, (13)C NMR, distortionless enhancement by polarization transfer (DEPT), H,H correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond correlation (HMBC). The structure of known compounds 2-5 were identified by comparison of their spectral data with those reported in the literature.     

An efficient method for purification of nonspecific lipid transfer protein‐1 from rice seeds using kiwifruit actinidin proteolysis and ion exchange chromatography

Plant nonspecific lipid transfer proteins are small basic proteins that transport phospholipids between membranes and are subdivided into two subfamilies, nsLTP₁ (9 kDa) and nsLTP₂ (7 kDa). LTPs have potential application in the defense reactions against pathogens and the drug delivery systems. Many efforts have been made for purification of different nsLTPs from various plants; however, most of them used successive purification procedures. We have developed a relatively simple and efficient method for the purification of rice nsLTP₁, based on the proteolytic activity of kiwifruit actinidin on the rice seed extract and one‐step chromatographic procedure on a CM‐Sepharose column. The purity of protein was determined by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). The isolated LTP₁ migrated as a homogenous polypeptide with molecular mass of 9 kDa that confirms the efficiency of actinidin on the digestion of major contaminations present in the rice seed extract without any harmful effect on the LTP₁. The advantages of using proteolytic activity of actinidin in purifying rice LTP₁ includes the reduced separation time allowing the purification of LTP₁ in one‐step chromatographic procedure, low costing, high efficiency, and the relative simplicity of the method.     

Boron nitride nanotubes with quadrangular cross sections: Density functional studies

Density functional theory (DFT) calculations have been performed to investigate the availabilities and properties of boron nitride nanotubes (BNNTs) with quadrangular cross sections. To achieve the purposes, the original structure of a representative BNNT was individually decorated by the carbon and silicon atoms to make the C-BNNT and Si-BNNT models. The sp³ hybridizations were set for the C and Si atoms to make possible the formation of the quadrangular cross sections for the BNNTs. The optimized results indicated that the investigated models could be stabilized; however, they showed different properties. The atomic scale properties based on computations of quadrupole coupling constants (C_Q) also approved different properties for the C-BNNT and Si-BNNT models. Moreover, the C_Q parameters indicated that the properties of C-BNNT could be considered similar to the original BNNT; however, more discrepancies were observed for the Si-BNNT.     

The Anticancer Activity and HSA Binding Properties of the Structurally Related Platinum (II) Complexes

The development of resistance and unwanted harmful interaction with other biomolecules instead of DNA are the major drawbacks for application of platinum (Pt) complexes in cancer chemotherapy. To conquer these problems, much works have been done so far to discover innovative Pt complexes. The objective of the current study was to evaluate the anti cancer activities of a series of four and five-coordinated Pt(II) complexes, having deprotonated 2-phenyl pyridine (abbreviated as C^N), biphosphine moieties, i.e., dppm?=?bis(diphenylphosphino) methane (Ph₂PCH₂PPh₂) and dppa?=?bis(diphenylphosphino)amine (Ph₂PNHPPh₂), as the non-leaving carrier groups. The growth inhibitory effect of the Pt complexes [Pt(C^N)(dppm)]PF₆: C ₁ , [Pt(C^N)(dppa)]PF₆: C ₂ , and [Pt(C^N)I(dppa)]: C ₃ , toward the cancer cell lines was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. In addition, the florescence quenching experiments of the interaction between human serum albumin (HSA) and the Pt complexes were performed in order to obtain the binding parameters and to evaluate the denaturing properties of these complexes upon binding to the general carrier protein of blood stream. The structure?Cactivity relationship studies reveal that four-coordinated Pt complexes C ₁ and C ₂ with both significant hydrophobic and charge characteristics, not only exhibit strong antiproliferation activity toward the cancer cell lines, but also they display lower denaturing effect against carrier protein HSA. On the other hand, five-coordinated C ₃ complex with the unusual intermolecular NH??Pt hydrogen binding and the intrinsic ability for oligomerization, exhibits poor anticancer activity and strong denaturing property. The current study reveals that the balance between charge and hydrophobicity of the Pt complexes, also their hydrogen binding abilities and coordination mode are important for their anticancer activities. Moreover, this study may suggest C ₁ and C ₂ as the potential template structures for synthesis of new generation of four-coordinated Pt complexes with strong anticancer activities and weak denaturing effects against proteins.     

甘肃岷县不同生长年限当归药材的红外光谱分析

采用傅里叶变换红外光谱(FTIR)及其二阶导数谱对不同生长年限当归药材进行分析研究.结果表明,不同生长年限当归药材的红外图谱较为相似,仅从一维谱图上无法反映出不同生长年限当归药材的红外特征谱明显的异同,但通过二阶导数图谱中1771、1747、1712、1559、1514、1466、766、711cm-1和668cm-1处的峰型差异可发现不同生长年限当归药材之间的一些成分存在较明显的差异.由于生长时间不同,导致它们的化学成分存在差异,所以体现了各自的红外特征谱,其中第三年当归药材与第一年和第二年当归药材间差异较大.     

Numerical range of operators acting on Banach spaces

The aim of the paper is to propose a definition of numerical range of an operator on reflexive Banach spaces. Under this definition the numerical range will possess the basic properties of a canonical numerical range. We will determine necessary and sufficient conditions under which the numerical range of a composition operator on a weighted Hardy space is closed. We will also give some necessary conditions to show that when the closure of the numerical range of a composition operator on a small weighted Hardy space has zero.     

J/ψ核吸收新截面难以改变吸收机制的局面

将新发表的J/ψ核吸收截面输入强子和弦级联模型JPCIAE,计算了200AGeV/c的P-A,O-U,S-U和Pb-Pb最小偏畸碰撞中J/ψ压低因子并与实验作比较.结果表明:增大的新截面难以改变核吸收机制不易解释Pb-Pb碰撞J/ψ反常压低局面.     

General Formulations of Finite-field Method Classified by Symmetry for Molecular Linear and Nonlinear Polarizabilities

1 INTRODUCTIONWith the invention of lasers[1] and the observation of second-harmonic generation in quartz[2], nonlinear optics(NLO), as a cornerstone of photonics, has been booming since 1960's. And intense interest has been aroused to search materials exhibiting appropriate nonlinear optical properties suitable for the construction of practical optical devices for the important techniques such as frequency converting, signal processing and optical computing[3～6]. In order to determine …     

Net Charge Fluctuation and String Fragmentation

We present the simulation results of the net charge fluctuation in Au Au collisions at √Snn=130 GeV from a dynamic model, JPCIAE, and its revisions. The simulations are done for the quark-gluon matter, the directly produced pions, the pion matter, and the hadron matter. The simulated net charge fluctuation of the quark-gluon matter is close to the thermal model prediction for the quark-gluon gas. However, the discrepancy exists comparing the simulated net charge fluctuation for directly produced pions and the pion matter with the thermal model prediction for pion gas and the resonance pion gas, respectively. The net charge fluctuation of hadron matter from default JPCIAE simulations is nearly 3.5 times larger than quark-gluon matter. A discussion is given for the net charge fluctuation as an evidence of QGP phase transition.     

Highly selective thiocyanate poly(vinyl chloride) membrane electrode based on a cadmium–Schiff’s base complex

A PVC membrane electrode based on a cadmium–salen (N,N′-bis-salicylidene-1,2ethylenediamine) complex as an anion carrier is described. The electrode has an anti-Hofmeister selectivity sequence with a preference for thiocyanate at pH 1.5–11.0. It has a linear response to thiocyanate from 1.0 × 10^–6 to 1.0 × 10^–1 mol L^–1 with a slope of 59.1 ± 0.2 mV per decade, and a detection limit of 7 × 10^–7 mol L^–1. This electrode has high selectivity for thiocyanate relative to many common organic and inorganic anions. The proposed sensor has a fast response time of approximately 15 s. It was applied to the determination of thiocyanate in a milk sample. Received: 1 December 2000 / Revised: 19 April 2001 / Accepted: 30 April 2001