Chemical constituents isolated from stems of Schisandra chinensis and their antifeedant activity against Tribolium castaneum

Abstract

One new sesquiterpene (α-iso-cubebenol acetate, 8), together with 9 known compounds (1-7, 9, 10) were isolated from the stems of Schisandra chinensis (Turcz.) Baill. by repeated silica gel column chromatography. Based on the results of MS, NMR spectra and comparing with literature data, the six dibenzocyclooctadiene lignans were identified as schizandrin A to C (1-3), schizandrin (4), schisantherin A (5) and gomisin J (6), the two sesquiterpenes were identified as α-iso-cubebenol (7) and α-iso-cubebenol acetate (8), while the two triterpenic acids were identified as ganwuweizic acid (9) and kadsuric acid (10). The antifeedant activity of the 10 compounds against Tribolium castaneum adults was tested. Gomisin J (6) exhibited activity at 1500?ppm concentration with 40.3% antifeeding index percentages. As for the dibenzocyclooctene lignans (compounds 1–3, 6), the number of methylenedioxies and the position of hydroxyl groups were the main factors to affect their antifeedant activities.     

SNCR应用于水泥窑氮氧化物控制的氨氧化

为了对水泥窑应用SNCR控制技术时CaO催化NH3氧化问题进行研究,该文采用固定床反应器,研究温度(650～950℃)、NH3体积分数(100×10-6～1500×10-6)和O2体积分数(0～4%)对于CaO催化NH3氧化作用的影响。采用Fourier变换红外光谱仪(FTIR)测量NH3和NO组分的体积分数。实验结果表明:CaO催化NH3氧化反应的转化率和产物NO的选择性随NH3体积分数增加而下降,随温度和O2体积分数增加而增加。基于NH3转化率和产物NO选择性随NH3体积分数的变化规律,提出CaO催化NH3氧化的首要途径是NH3和O2的吸附,吸附态NH3会与O2反应生成NO,而非前人提出的NH3与CaO反应生成CaN。采用该机理可以较好地解释实验规律。     

O2/CO2气氛下燃煤过程中SO2排放特性实验

通过沉降炉对O2/CO2气氛和空气气氛下煤粉燃烧过程中SO2排放特性进行实验,结果表明,随燃料/氧化学当量比的增加,烟气中SO2浓度升高,单位煤生成SO2的量随燃料/氧化学当量比的增加而减少.在实验条件下,不加石灰石时,气氛和温度对SO2的生成无明显影响,SO2的生成量只与煤中含硫量以及煤的种类有关.当煤中加入石灰石后,O2/CO2气氛下SO2的排放量远小于空气气氛下,这主要是因为石灰石在O2/CO2气氛下取得的脱硫效率大大高于空气气氛下的脱硫效率.     

Estrogenic Activity of Mycoestrogen (3β,5α,22E)-Ergost-22-en-3-ol via Estrogen Receptor α-Dependent Signaling Pathways in MCF-7 Cells

Armillariella tabescens (Scop.) Sing., a mushroom of the family Tricholomataceae, has been used in traditional oriental medicine to treat cholecystitis, improve bile secretion, and regulate bile-duct pressure. The present study evaluated the estrogen-like effects of A. tabescens using a cell-proliferation assay in an estrogen-receptor-positive breast cancer cell line (MCF-7). We found that the methanol extract of A. tabescens fruiting bodies promoted cell proliferation in MCF-7 cells. Using bioassay-guided fractionation of the methanol extract and chemical investigation, we isolated and identified four steroids and four fatty acids from the active fraction. All eight compounds were evaluated by E-screen assay for their estrogen-like effects in MCF-7 cells. Among the tested isolates, only (3β,5α,22E)-ergost-22-en-3-ol promoted cell proliferation in MCF-7 cells; this effect was mitigated by the ER antagonist, ICI 182,780. The mechanism underlying the estrogen-like effect of (3β,5α,22E)-ergost-22-en-3-ol was evaluated using Western blot analysis to detect the expression of extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K), Akt, and estrogen receptor α (ERα). We found that (3β,5α,22E)-ergost-22-en-3-ol induced an increase in phosphorylation of ERK, PI3K, Akt, and ERα. Together, these experimental results suggest that (3β,5α,22E)-ergost-22-en-3-ol is responsible for the estrogen-like effects of A. tabescens and may potentially aid control of estrogenic activity in menopause.     

纤维素衍生物手性固定相研究进展

本文从用作手性固定相的纤维素衍生物种类、纤维素衍生物手性固定相制备方法及其在高效液相色谱中的应用三个方面介绍了国内外近年来的研究进展,并展望了该领域今后的研究方向。     

一种高灵敏度测定血红蛋白的化学发光分析方法

研究了在碱性介质和阳离子表面活性剂CTMAB存在下,牛血红蛋白催化鲁米诺-铁氰化钾的化学发光行为和化学发光反应的条件,提出一种流动注射-化学发光法测定牛血红蛋白的新方法.该方法测定牛血红蛋白的线性范围为5.18×10-10~1.29×10-6mol/L,r2=0.998 5;检出限(RSN=3)为1.2×10-10mol/L;回收率为(100±10)%;dRSD≤5%(n=6).     

黄芪中微量元素的形态分析

按照传统煎煮法对中药黄芪中铜、锌、铁、镁、钙和铬6种元素进行提取;用微孔滤膜分离提取液中的可溶态与悬浮态;利用大孔吸附树脂柱对可溶态中的有机态与无机态进行分离;采用火焰原子吸收光谱法对各种形态中的6种元素进行测定。结果显示:黄芪中6种元素的总提取率在44.0%~74.4%,浸留比在79·4%~293.8%,悬浮态颗粒吸附率在10%左右,可溶态中铬的有机态与无机态的比例为114.6%,铜、锌、铁、镁、钙的有机态与无机态的比例在3.7%~43.5%。该法对各元素的加标回收率在96.8%~103.1%;相对标准偏差小于1.5%。     

Highly efficient excitation of LP_(01) mode in ring-core fibers by tapering for optimizing OAM generation

We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fiber orbital angular momentum(OAM)generation.The tapering technique has been investigated theoretically and experimentally.Before tapering,only 50%of light can be coupled from SMFs to RCFs.The modal interference spectrum with an extinction ratio(ER)of～9 dB is observed,showing that higher-order modes are excited in RCF.By tapering the spliced point,90%of light is coupled,and the ER is minimized to be～2 dB,indicating that the higher-order modes are effectively suppressed by tapering.Such tapered spliced points of RCF–SMF are further applied for all-fiber OAM generation.The efficiencies of OAM+1 and OAM?1 generation are found to be enhanced by approximately 11.66%and 12.41%,respectively,showing that the tapered spliced point of the RCF–SMF is a feasible way to optimize OAM generation.     

CaPtAs: A new noncentrosymmetric superconductor

We report the discovery of a new noncentrosymmetric superconductor CaPtAs.It crystallizes in a tetragonal structure(space group I41md,No.109),featuring three dimensional honeycomb networks of Pt-As and a much elongated c-axis(a=b=4.18?,and c=43.70?).The superconductivity of CaPtAs with Tc=1.47 K was characterized by means of electrical resistivity,specific heat,and ac magnetic susceptibility.The electronic specific heat Ce(T)/T shows evidence for a deviation from the behavior of a conventional BCS superconductor,and can be reasonably fitted by a p-wave model.The upper critical fieldμ0Hc2 of CaPtAs exhibits a moderate anisotropy,with an in-plane value of around 204 mT and an out-of-plane value of 148 mT.Density functional theory calculations indicate that the Pt-5 d and As-4 p orbitals mainly contribute to the density of states near the Fermi level,showing that the Pt-As honeycomb networks may significantly influence the superconducting properties.     

压电式微滴按需喷射的过程控制和规律

微滴喷射增材制造技术中沉积微滴的大小与均匀性是影响成型件质量的关键因素.本文设计了一种用于生成均匀微滴的压电驱动式微滴喷射装置,通过压电材料带动柔性膜片振动,将液体从喷嘴中喷出生成微滴,采用数值模拟和实验相结合的方法,研究了不同控制参数下膜片振幅及其对生成微滴尺寸和均匀性的影响.研究结果表明:膜片振幅大小受到驱动电压和压电频率的共同影响,压电频率是导致膜片中心点振幅实验测量值小于理论计算值的主要原因,膜片振动会导致喷嘴内部压力发生变化从而影响微滴生成尺寸.在相同驱动电压条件下,压电频率为10 Hz时存在压电膜片振幅最大值.随着膜片振幅的增大,喷孔处液体速度和液柱长度增大到临界值时可以生成微滴,当喷孔处的液柱长度超过临界值时,会形成卫星液滴. 当膜片振幅区间在30 $\mu$m$\sim $42 $\mu $m可以稳定生成微滴,生成最小微滴尺寸为339.8$\mu$m,直径最大变化率为0.29%,相邻两微滴间距最大变化率为2.67%,生成微滴的尺寸及均匀性较好.研究结果有助于提高压电式微滴喷射装置的液滴生成质量.