Anti-acetylcholinesterase and antioxidant activity of essential oils from Hedychium gardnerianum Sheppard ex Ker-Gawl

Acetylcholinesterase inhibition, antioxidant and cytotoxic activities of Hedychium gardnerianum leaf essential oils from S. Miguel Island were determined. All the oils inhibited acetylcholinesterase, with IC(50) values of approximately 1 mg/mL, showing no statistical differences between collection sites. Three oils presented mixed inhibition, whilst one was almost truly competitive. This activity can be attributed to the presence of sesquiterpenes, which constituted more than 60% of the composition of the oils. Regarding the antioxidant activity as measured by the DPPH method, all the oils presented activities similar to reference compounds, although with statistical differences between collection sites. Cytotoxicity measured using Artemia salina classified these oils as moderately toxic, with LC(50) values ranging from 300 to 500 μg/mL. These results indicate a possible application of these oils in aromatherapy as coadjuvants in the treatment of cognitive diseases such as Alzheimer, since they may contribute to increase acetylcholine in cholinergic neurons and simultaneously fight deleterious oxidations responsible by neurological degeneration.     

Development of a bar adsorptive micro-extraction–large-volume injection–gas chromatography–mass spectrometric method for pharmaceuticals and personal care products in environmental water matrices

The combination of bar adsorptive micro-extraction using activated carbon (AC) and polystyrene–divinylbenzene copolymer (PS-DVB) sorbent phases, followed by liquid desorption and large-volume injection gas chromatography coupled to mass spectrometry, under selected ion monitoring mode acquisition, was developed for the first time to monitor pharmaceutical and personal care products (PPCPs) in environmental water matrices. Assays performed on 25 mL water samples spiked (100 ng L⁻¹) with caffeine, gemfibrozil, triclosan, propranolol, carbamazepine and diazepam, selected as model compounds, yielded recoveries ranging from 74% to 99% under optimised experimental conditions (equilibrium time, 16 h (1,000 rpm); matrix characteristics: pH 5, 5% NaCl for AC phase; LD: methanol/acetonitrile (1:1), 45 min). The analytical performance showed good precision (RSD < 18%), convenient detection limits (5–20 ng L⁻¹) and excellent linear dynamic range (20–800 ng L⁻¹) with remarkable determination coefficients (r ² > 0.99), where the PS-DVB sorbent phase showed a much better efficiency. By using the standard addition methodology, the application of the present analytical approach on tap, ground, sea, estuary and wastewater samples allowed very good performance at the trace level. The proposed method proved to be a suitable sorption-based micro-extraction alternative for the analysis of priority pollutants with medium-polar to polar characteristics, showing to be easy to implement, reliable, sensitive and requiring a low sample volume to monitor PPCPs in water matrices.     

一种镍的二胺和β-二酮混合配体配合物在不同醇中热致-溶致变色行为的可见光谱研究

用可见光谱法对一种Ni(II)的二胺和β-二酮类混合配体配合物([Ni(II)(Me4en)(acac)]ClO4)在四种醇类溶剂中所形成的正方平面体和变形八面体物种的平衡过程进行了研究. 通过对配合物在醇中的热致-溶致变色光谱曲线的分峰拟合处理, 计算出了这一过程的平衡常数, 焓变△H和熵变△S等热力学函数, 同时, 得到了正方平面体和变形八面体物种各自的光谱吸收曲线. △H数据表明, 在醇中形成变形八面体物种是一个放热过程, 放热量的大小反映了醇分子与配合物中心离子Ni(II)配位能力的强弱. △S的绝对值与中心离子Ni(II)配位的或释放的醇分子数相关. 计算结果对深化认识Ni(II)的二胺和β-二酮类混合配体配合物热致变色的本质有所帮助.     

Outlier detection of air temperature series data using probabilistic finite state automata‐based algorithm

This article proposes a probability finite state automata‐based algorithm (PFSAA) for detecting outliers of air temperature series data caused by sensor errors. This algorithm first divides the training samples of air temperature series data into subclusters that will be further used to build finite state automata by splitting and combining techniques. Then, it creates a dynamic transition matrix of PFSA based on probability theories. Finally, the outliers of the remaining test samples are detected by PFSAA. The proposed algorithm is quantitatively validated by the reference data and a traditional backpropagation neural net model. © 2012 Wiley Periodicals, Inc. Complexity, 2012     

ABO_2型复合氧化物上CO-NO的反应性能

以柠檬酸络合法制备了 CuCrO_2、 CuAlO_2和 CuFeO2等具有铜铁矿结构的 ABO2型复合氧化物,并考察了它们在氧化和还原气氛中对 CO- NO反应的影响 . CuAlO_2和 CuCrO_2具有好的催化活性, CuCrO_2更具有相当的稳定性,经过氧化和还原条件下的 CO- NO反应后,体相组成仍然保持不变 . CuAlO_2在还原条件下,部分被还原生成了零价铜 . CuFeO_2的催化活性和稳定性较差,在还原气氛中催化 CO- NO反应过程中,样品被还原,完全转化成了 Cu0和 CuFe2O4.     

Structural Transformation of the Peptide Fragments from the Reactive Center Loops of Serpins: Circular Dichroic Studies

Two peptides, derived from the reactive center of ovalbumin (OVARC) and plasminogen activator inhibitor‐1 (PAIRC) respectively were chemically synthesized and investigated by circular dichroic spectroscopy. The secondary structural transformation in solution and in solid state was studied. OVARC shows a nascent helical structure in aqueous solution, and its helical content increases under acidic conditions. There is no obvious structural conversion from solution to solid state. PAIRC, however, undergoes a structural transformation from random coil in aqueous solution to a typical β‐sheet structure in the solid state. Hexafluoroisopropanol (HFIP) prompts helical structures of the two peptides in solution, but it seems to trigger the structural formation of β‐sheets in solid state. The novel structural transformation from random coil or nascent helical structure in aqueous solution to the α‐helix in HFIP and to the β‐sheet structure in solid state may reflect the conformational polymorphism of the serpin reactive centers and is implicated in the structural features of the amyloid aggregates.     

Fe1-xO基氨合成催化剂的制备化学

采用高温熔融法制备了各类铁氧化物,用XRD分析了熔融过程中的物相变化,EOS考察了熔融体凝固-冷却速率对助催化剂分布的影响.结果表明,采用大气气氛中的高温熔融法不能制取Fe₂O₃和化学计量比的FeO,前者会发生分解反应,后者会发生歧化反应;在1.333≤n(O)/n(Fe)<1.38范围时,可以制取Fe₃O₄或非化学计量比的Fe₃-yO₄;在1.113O₄和FeO的混合氧化物;在1.0451-xO,即维氏体.Fe_1-xO基催化剂的制备必须采用物理熔融与化学反应相结合的工艺.凝固冷却速度对抑制氧化亚铁的氧化反应和歧化反应,保证助催化剂的均匀分布和晶粒度均有很大影响     

活体生物膜控制合成纳米半导体硫化镉

目前 ,用于合成和制备纳米材料的方法除化学和物理方法[1～ 4] 外 ,还有仿生法[5～ 7] ,但尚未见到利用活体生物膜来合成无机纳米材料的报道 .本文利用绿豆芽通过生物膜控制合成了纳米ＣｄＳ .1　实验部分将市售新鲜绿豆芽用去离子水洗净后放入盛有 0 .1ｍｏｌ·Ｌ- 1 Ｎａ2 Ｓ水溶液的试管中 ,浸没茎部 ,露出叶片 .2 4ｈ后取出 ,用去离子水冲洗掉豆芽外部的Ｎａ2 Ｓ溶液 ,转放到盛有ＣｄＣｌ2 水溶液的试管中 ,用同法浸泡 2 4ｈ .取出豆芽 ,小心用玻璃棒将豆芽茎外的黄色ＣｄＳ转入无水乙醇中 .取少量ＣｄＳ乙醇溶液 ,经超声振荡后上铜网 ,…     

关于亚纯多叶函数的子类

本文引进单位圆盘内以原点为p级极点的亚纯多叶函数的新子类M_p(n,λ,A,B) (p是正整数,n是非负整数,-1≤B＜A≤1,-π/2＜λ＜π/2,证明M_p(n+1,λ,A,B)?M_p(n,λ,A,B),研究类中函数的积分变换,得到准确的系数估计和一个卷积性质.     

Characteristics of the Raman spectra of archaeological Malachites

Archaeological malachites, represented by the malachites found on the ancient Chinese and Vietnamese copper/bronze coins, may also incorporate those on other archaeological objects. The Raman spectra with Ar laser of these malachites differ slightly from those of the natural malachites found in mines. In this study, 120 measurements of the malachites on 40 coins identified 26 bands, while only around 18 of them are frequently observed. The wavenumbers (cm⁻¹), shifts (±)and relative intensities (in parentheses) of the 18 common bands read, respectively: 153±4 (0‐vs), 179±7 (m‐vs), 217±8 (m‐vs), 274±7 (0‐vs), 355±5 (0‐m), 431±4 (0‐vs), 514±3 (0‐m), 533±5 (0‐s), 566±3 (0‐m), 599±2 (0‐m), 718±6 (0‐m), 754±2 (0‐m), 1061±7 (0‐m), 1093±10 (0‐m), 1365±9 (0‐m), 1491±7 (0‐vs), 3321±11 (0‐vs) and 3380±7 (0‐vs). In comparison with those of the 105 measurements on the natural malachites in five mines, the Raman spectra of the archaeological malachites tend to show less bands, higher backgrounds and greater shifts in the wavenumber position. The weakening or loss of bands is in the order of the OH stretch (3300 cm⁻¹) (most severe), CO₃ (600–1500 cm⁻¹) and CuO (<600 cm⁻¹) (less severe) groups, indicating successive stages of corrosion. The malachites on the coins from three climate zones show their own characteristics. Several coins may have experienced two or more climatic or geologic episodes and show complex Raman spectra different from those of the natural malachites. Copyright © 2012 John Wiley & Sons, Ltd.