Fabrication of alizarin red S/multi-walled carbon nanotube nanocomposites and their application in hydrogen peroxide detection

In this work, an easy and effective method to synthesize alizarin red S/multi-walled carbon nanotube (ARS/MWCNT) nanocomposites based on the π–π stacking non-covalent interactions between ARS and MWCNTs was introduced. The characters of ARS/MWCNT nanocomposites were investigated by Fourier transformation infrared spectroscopy, UV–Vis spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscope, and electrochemical techniques. ARS tightly coating on MWCNTs surface makes the nanocomposites good dispersibility in water and excellent electrochemical activity. Because of the combination of the excellent electroactivity of ARS and the unique properties of MWCNTs, ARS/MWCNT nanocomposites-modified glassy carbon electrode exhibits a good response to the reduction of hydrogen peroxide and takes on a promising prospect of the practical application in electrochemical sensors field.     

规模化制备藻蓝蛋白工艺技术研究进展

藻蓝蛋白作为蓝色天然色素蛋白,具有抗氧化、清除体内自由基、增强机体免疫力、抗炎、保肝护肝等生理功能及高效的荧光特性,被广泛应用于食品、化妆品、医药、分子探针等领域。现今制约藻蓝蛋白大规模商业化生产的主要原因是没有稳定、高效、经济的制备工艺。文中综述了近几年藻蓝蛋白制备工艺中发展较快、实用性较强的工艺技术,并在此基础上提出了一种工艺方案。     

单环刺螠废弃内脏中粗多糖的提取工艺优化

利用热水浸提的方法进行单环刺螠（海肠）废弃内脏中多糖的提取。采用单因素试验和L₉（3⁴）正交试验设计,研究不同pH值、料液比、提取时间和提取温度对单环刺螠内脏多糖提取率的影响。并采用Fenton体系测定单环刺螠内脏多糖对羟自由基（·OH）的清除作用。单环刺螠内脏多糖提取的最佳工艺条件为pH10、料液比1:40（g/mL）、时间3h、温度60℃。单环刺螠内脏多糖在质量浓度为50μg/mL时,对羟自由基清除能力可达60%,且具有剂量效应。     

Methoxy poly(ethylene glycol)-grafted-chitosan based microcapsules: Synthesis, characterization and properties as a potential hydrophilic wall material for stabilization and controlled release of algal oil

Methoxy poly(ethylene glycol)-grafted-chitosan (mPEG-g-CS) was synthesized in an attempt to increase the water solubility of CS, and it was applied as wall material to microcapsulate algal oil (AO). Both Fourier transformed-infrared (FT-IR) spectra and solubility test confirmed that mPEG had been successfully grafted onto CS. The larger particles showed smooth surfaces, whereas smaller ones presented surface folds. The amount of free and total oil were 2.73 and 47.87 g/100 g, respectively, with high encapsulation efficiency of 94.30%. Fourteen fatty acids were detected in free algal oil (FAO) and microcapsulated algal oil (MAO), and the important fatty acids were preserved after microcapsulation. AO contained within microcapsules was protected from UV-light and heat compared with FAO. Release rate of AO was initially rapid and then followed by controlled release with the erosion mechanism playing a dominant role. The mPEG-g-CS proved to be a promising wall material with excellent solubility and film forming ability, and therefore supplied great potential applications in food industry.     

Determination of critical aggregation concentration and aggregation number of acid-soluble collagen from walleye pollock (Theragra chalcogramma) skin using the fluorescence probe pyrene

The aim of this paper was to investigate the critical aggregation concentration and aggregation number of acid-soluble collagen from walleye pollock (Theragra chalcogramma) skin using the fluorescence probe pyrene. Results showed that pyrene was fit for studying the aggregation behaviour of collagen in sodium phosphate buffer at pH 7.2. The plots of the pyrene I₁/I₃ ratio, as a function of the logarithm of total collagen concentration, revealed a typical sigmoidal decrease, the critical aggregation concentration (CAC) from which was determined to be at 0.48 mg/ml. The subsequent transient fluorescence decay study indicated that the aggregation number of collagen was not constant, but varied with different concentrations of collagen. The structure of the aggregates tended to be stable, when the collagen concentration exceeded 1.2 mg/ml.     

Cd~(2+)与2,4,6-TCP联合胁迫下日本青鳉的逐级行为响应

采用水质安全在线生物预警系统(BEWs)记录行为强度数据,探讨了2种环境污染物Cd2+和2,4,6-TCP联合胁迫下,不同暴露浓度、不同暴露时间日本青鳉的行为响应。在不同浓度比例的农药暴露中,10,5,1和0.1TU的暴露浓度下的平均行为反应时间分别为3.9,7.2,28.2和43.6h。结果表明,在2种污染物的暴露下,日本青鳉的逐级行为响应既受化合物浓度高低的影响,又受暴露时间的影响,但每个浓度的不同配比之间的行为响应时间差异不明显,而且每个浓度2种污染物不同配比暴露下日本青鳉的逐级行为响应基本一致。日本青鳉对Cd2+污染的行为反应具有明显的滞后性,即由于毒性累积作用,Cd2+对日本青鳉产生的环境胁迫小于相同浓度的2,4,6-TCP。     

Influences of free-air CO2 enrichment (FACE), nitrogen fertilizer and crop residue incorporation on CH4 emissions from irrigated rice fields

To investigate the response of methane (CH₄) emissions to an elevated atmospheric carbon dioxide (CO₂) concentration (200?±?40???mol?mol^?1 higher than the ambient atmosphere), we performed a 4-year multi-factorial experiment at a subtropical rice paddy that contained sandy loam soil in the Yangtze River Delta from 2004 to 2007 using free-air CO₂ enrichment (FACE) technology. Our results revealed that the elevated atmospheric CO₂ increased the seasonal cumulative CH₄ emissions by 15?% on average during the 4-year period. The increase was insignificant and much weaker than the previous studies, which might be primarily attributed to the absence of a significant difference in the rice biomass between the two CO₂ levels in half of the field treatments. Crop residue incorporation hindered the stimulatory effects induced by the elevated CO₂, which were 37, 14 and 6?% for the fields that were incorporated with none, half or all of the wheat straws that were harvested in the preceding winter wheat season, respectively. Nitrogen fertilizers application also hindered the stimulatory effects of the elevated CO₂ on the CH₄ emissions. The CO₂ stimulatory effect was 39?% for the field without nitrogen fertilizers, and reduced to 17, 7 and 5?% for the field with nitrogen fertilization of 125, 250 and 350?kg?N?ha^?1, respectively. The regulation of nitrogen fertilizers on the CO₂ effects in this experiment does not well agree with the previous studies, which might because the soil type was different from those of the previous studies. Thus, further studies are necessary to evaluate the role of soil properties in regulating the effects of elevated atmospheric CO₂ on CH₄ emissions from managed and natural wetlands. There were no significant interactions between the atmospheric CO₂ and the incorporations of nitrogen fertilizer and crop residue. Appropriate experiments are necessary for better understanding of the interact influences of the elevated CO₂ and farm managements.     

全光谱法COD测量仪在水质监测中的应用

传统的COD测量方法需要消耗大量的化学试剂,容易对环境产生二次污染,测试成本高,而且难以实现在线自动检测。是能公司研制的全光谱法COD在线水质监测仪可在无人干预的情况下完成自动清洗、测试和数据处理等操作,本文将从用户的角度对其各方面性能进行考察,实际测量了烟台市内的部分湖水和河水样品,并与实验室的测试结果进行对比。实验结果证明,该仪器无需任何化学试剂,线性范围宽(0～160 mg/L),检出限低(0.36 mg/L),测定速度快(30 s/样),精密度好,满足国内在线检测仪器的各项指标,可以实现在线实时监测。     

紫外吸收全光谱法测定海水硝酸盐研究

紫外吸收全光谱法用于探测海水中硝酸盐浓度,具有测试结果准确可靠,简单快速,实用性强等特点。文中实验采用紫外吸收全光谱法在200~370 nm波段测试了硝酸盐和溴离子、氯离子、亚硝酸盐、浊度,以及他们与硝酸盐的混合溶液。分析了这些对测定海水硝酸盐有干扰影响的物质的紫外吸收光谱,并与硝酸盐做了对比分析,获得了硝酸盐和干扰物质的紫外吸收光谱特性,以及吸光度随波长变化的规律。通过硝酸盐浓度与吸光度的线性拟合曲线,显示二者有良好的线性关系,验证了实验的准确性。结果表明,使用紫外吸收全光谱法可用于测定海水中的硝酸盐。