液相色谱-串联质谱法测定牛奶中5种多肤类抗生素

建立了牛奶中杆菌肽、粘杆菌素A、粘杆菌素B、维吉尼霉素和万占霉素5种多肽类抗生素的反相液相色谱-串联质谱(HPLC-MS/MS)检测方法.牛奶样品经甲醇-0.1%甲酸水提取后,用4%三氯乙酸乙睛除蛋白,液-液萃取后,采用0.1%甲酸(A)和0.1%甲酸乙腈(B)作为流动相进行梯度洗脱.质谱(ESI+)采用多离子检测模式...     

Transformations of iodine species inside elliptical channels of AlPO4‐11 crystals at low temperature: a Raman study

Raman spectra of iodine species confined in one‐dimensional elliptical channels of AlPO₄‐11 (AEL) crystals have been studied from room temperature down to −196 °C. As temperature decreases, thermal fluctuations of individual iodine molecules confined in AEL channels are slowed down and they prefer to rotate to channel axis direction, which increases the population of iodine molecules along channel axis (i.e., lying molecules and chains). Such temperature‐driven orientation transformation of iodine molecules is found to be reversible upon heating up to room temperature. The experimental observations are in good agreement with our theoretical simulations by molecular dynamics on low density iodine‐filled AEL crystals. We thus provide a new way to modulate the orientation of iodine molecules in nanochannels, which may have implications in low‐temperature‐sensitive nanoscale devices. Copyright © 2015 John Wiley & Sons, Ltd.     

Simultaneous voltammetric determination of ascorbic acid and uric acid using a Nafion/multi-wall carbon nanotubes composite film-modified electrode

A Nafion/multi-wall carbon nanotubes (MWNT) composite film-modified electrode was fabricated. The modified electrode showed excellent electrocatalytic activity toward ascorbic acid (AA) and uric acid (UA) in 0.1-mol L⁻¹ NaCl medium (pH 6.5). Compared to the bare electrode that only displayed a broad and overlapped oxidation peak, the Nafion/MWNT film-modified electrode not only remarkably enhanced the anodic peak currents of AA and UA but also avoided the overlapping of the anodic peaks of AA and UA with a 320-mV separation of both peaks. Under the optimized conditions, the peak currents of AA and UA were proportional to their concentration at the ranges of 8.0 × 10⁻⁵ to 6.0 × 10⁻³ mol L⁻¹ and 6.0 × 10⁻⁷ to 8.0 × 10⁻⁵ mol L⁻¹, respectively. The proposed method was used for the detection of AA and UA in real samples with satisfactory results.     

地黄提取物改善贫血大鼠记忆及其机制

地黄滋阴补血填髓,广泛用于贫血和脑疾病患者,但其功效机制尚未阐明.本文探讨地黄水提物(Rehmannia glutinosa’s water extracts,RGWE)改善血虚大鼠记忆及其滋阴补血填髓的可能机制.采用断尾放血结合注射环磷酰胺制备贫血大鼠模型,随机分溶媒组和地黄水提物3,6,10g/kg治疗组,灌服等体积自来水或不同剂量地黄水提物10天,采用Morris水迷宫观测大鼠空间记忆能力,采用酶联免疫吸附测定方法(Enzyme linked immunosorbent assay,ELISA)检测血浆红细胞生成素(EPO)水平,免疫组化和免疫蛋白印迹技术(Western blotting)检测分析脑EPO及其受体表达水平.成功制备血虚模型,表现为大鼠红细胞数和血红蛋白显著下降,与造模前比较差异显著(P<0.05),溶媒组空间记忆能力显著下降,地黄治疗组空间记忆能力明显提高,逃避潜伏期明显缩短(P<0.05),一定时间内穿越平台次数显著增多(P<0.05);免疫组化和Western blotting结果显示脑组织EPO及其受体表达、血浆EPO水平均较溶媒组明显升高(P<0.05).地黄水提物显著提高贫血...     

Synthesis of copolymers of poly(ether sulfone ether ketone ketone) and poly(ether ketone diphenyl ketone ether ketone ketone) by electrophilic Friedel–Crafts solution polycondensation

A new monomer, 4,4′‐bis(4‐phenoxybenzoyl)diphenyl(BPOBDP), was synthesized via a two‐step synthetic procedure. A series of novel poly(ether sulfone ether ketone ketone)/poly(ether ketone diphenyl ketone ether ketone ketone) copolymers were prepared by electrophilic Friedel–Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of 4,4′‐diphenoxydiphenylsulfone (DPODPS) and 4,4′‐bis(4‐phenoxybenzoyl)diphenyl (BPOBDP), in the presence of anhydrous aluminum chloride and N‐methylpyrrolidone (NMP) in 1,2‐dichloroethane (DCE). The copolymers with 10–50 mol% DPODPS are semicrystalline and have remarkably increased T_gs over commercially available PEEK and PEKK. The copolymers with 40–50 mol% DPODPS had not only high T_gs of 170–172°C, but also moderate T_ms of 326–333°C, which are extremely suitable for melt processing. These copolymers have tensile strengths of 96.5–108.1 MPa, Young's moduli of 1.98–3.05 GPa, and elongations at break of 13–26% and exhibit excellent thermal stability and good resistance to acidity, alkali, and common organic solvents. Copyright © 2009 John Wiley & Sons, Ltd.     

锂离子电池负极CaSnO3制备及性能

应用水热法合成前驱物CaSn（OH）6,经高温煅烧而得CaSnO3.XRD、SEM、DSC-TGA表征其物相、表面形貌和相变过程,调节溶剂水和乙醇比例,可有效地控制前驱物的形态,从立方块到内凹立方块乃至枝状结构变化,高温煅烧前驱体可得到CaSnO3样品.CaSnO3电极比容量为334.4 mAh/g,呈现出优良的循环寿...     

Etherification of Ferrocenyl Alcohol by Highly‐efficient Ytterbium Triflate

Nucleophilic substitution of ferrocenyl alcohols with various aliphatic alcohols in the presence of a catalytic amount of ytterbium triflate [Yb(OTf)₃] was studied. It was found the unsymmetrical ferrocenyl ethers could be easily obtained in excellent yields when the reactions were performed in primary and secondary alcohols. However, in other organic non‐alcoholic solvents such as acetonitrile, the formation of symmetrical ferrocenyl ethers rather than unsymmetrical ones was observed.     

Bisabocurcumin, a new skeleton curcuminoid from the rhizomes of Curcuma longa L.

A new skeleton bisabolane-type sesquiterpene curcuminoid,bisabocurcumin(1),along with 5 known compounds,curcumin(2), demethoxycurcumin(3),bidemethoxycurcumin(4),(1E,4E)-1,5-bis(4-hydroxy-3-methoxyphenyl)-penta-1,4-dien-3-one(5),and (1E,4E)-1-(4-hydroxy-3-methoxyphenyl)-5-(4-hydroxy phenyl-)-penta-1,4-dien-3-one(6)were isolated from the rhizomes of Curcuma longa L.Their structures were determined on the basis of spectroscopic analysis.Bisabocurcumin(1) is firstly obtained from nature with a new skeleton combined by a bisabolane-type sesquiterpene and a 1,7-diphenylheptanoid through a C-C bond.     

Coral reef-like polyanaline nanotubes prepared by a reactive template of manganese oxide for supercapacitor electrode

Coral reef-like PANI nanotubes composed of nanopaticles were successfully synthesized by a reactive template of manganese oxide.The structure was characterized by using SEM,TEM,and FT-IR,and the supercapacitive behaviors of these nanotubes were investigated with cyclic voltammetry（CV）,and charge-discharge tests,respectively.A maximum specific capacitance of 533 F/g could be achieved in 1mol/L aqueous H₂SO₄ with the potential range of -0.2 to 0.8 V（vs.the saturated calomel electrode） in a half-cell setup configuration for PANI electrode,suggesting its potential application in the electrode material for electrochemical capacitors.     

高效液相色谱法同时测定复方草珊瑚含片中四种活性成分

提出了高效液相色谱法同时测定复方草珊瑚含片中原儿荼酸、3-羟基-4-甲氧基苯甲酸、异嗪皮啶和迷迭香酸的含量。样品经甲醇超声提取,用Waters Sun Fire ODS色谱柱(4.6 mm×150mm,5μm)分离,以不同比例混合的乙腈和磷酸-水(0.1+99.9)溶液为流动相进行梯度洗脱,流量0.8mL·min~(-1),在294 nm波长处用紫外检测器检测。在优化的色谱条件下,4种活性成分可完全分离。原儿茶酸、3-羟基-4-甲氧基苯甲酸、异嗪皮啶和迷迭香酸的线性范围分别为2.508～50.16,18.40～368.0,6.375～127.5,41.04～820.8ng;平均回收率分别为92.8%,93.1%,91.9%,99.6%;相对标准偏差(n=6)均不大于5.0%。