Effect of microbial hydrogen consumption on the hydrogen permeation behaviour of AISI 4135 steel under cathodic protection

The feasibility of microbial hydrogen consumption to mitigate the hydrogen embrittlement (HE) under different cathodic potentials was evaluated using the Devanathan-Stachurski electrochemical test and the hydrogen permeation efficiency η. The hydrogen permeation efficiency η in the presence of strain GA-1 was lower than that in sterile medium. The cathodic potential inhibited the adherence of strain GA-1 to AISI 4135 steel surface, thereby reducing the hydrogen consumption of strain GA-1. The adherent GA-1 cells were capable of consuming ‘cathodic hydrogen’ and reducing the proportions of absorbed hydrogen, indicating that it is theoretically possible to control HE by hydrogen-consuming microbes.     

海参铅同位素测定及产地溯源研究

目的 基于铅同位素实现对海参的产地溯源。方法 海参样品经冷冻干燥、粉碎、微波消解后,利用电感耦合等离子体-质谱法(inductively coupled plasma-mass spectrometry,ICP-MS)对海参铅同位素进行测定,对数据进行差异性分析,结合主成分分析和判别分析建立锦州、烟台、霞浦3个产区底播海参的判别模型。结果 调整样品消解液中总铅含量在5～20μg/L,采用10μg/L的标准溶液进行交叉测量,可对质量歧视效应进行准确修正;²⁰⁴Pb/²⁰⁶Pb、²⁰⁷Pb/²⁰⁶Pb和²⁰⁸Pb/²⁰⁶Pb的日内精密度分别为0.02%、0.02%和0.01%,日间精密度分别为0.04%、0.02%和0.01%。用此方法对生物成分分析标准物质大虾和扇贝的铅同位素进行测定,²⁰⁷Pb/²⁰⁶Pb和²⁰⁸Pb/²⁰⁶Pb的相对标准偏差小于0.1%,^20...     

盐渍海蜇脱铝研究及安全食用建议

目的采用不同弱酸浸泡盐渍海蜇脱铝,探讨海蜇产品铝含量超标安全风险,研究降低海蜇产品铝含量的食用方法。方法采用高纯水、盐酸、冰醋酸、柠檬酸以及食用醋5种不同溶液分别浸泡不同铝含量的盐渍海蜇除去盐渍海蜇中的铝,分析实验前后铝含量及观察实验前后样品感官变化。结果水浸泡法对降低海蜇中残留铝的效果有限;盐酸与柠檬酸溶液有较好的脱铝效果,但脱铝后海蜇样品韧性变差,品质下降;冰醋酸与食用醋溶液有较好的脱铝效果,且脱铝后海蜇样品有光泽,柔软饱满、有弹性,冰醋酸浓度为0.1 mol/L浸泡4h时和食用醋浓度为体积比1/9浸泡4 h,是最佳的浸泡浓度及时间,脱铝后海蜇样品铝含量符合SC/T3210-2001《盐渍海蜇皮和盐渍海蜇头》中明矾含量使用规定。结论建议生产者在生产即食海蜇时增加冰醋酸溶液浸泡工序,消费者在食用盐渍海蜇时进行食用醋溶液浸泡,以降低铝残留危害。     

利用稳定同位素进行农产品产地溯源和真伪鉴别研究进展

产地溯源是保护产品原产地信息及以假乱真等农产品安全问题的有效保障, 而稳定同位素溯源技术具有高精准的示踪及溯源能力, 是农产品产地溯源的有效手段, 该技术在国内外已有显著成果。基于这些研究成果, 本综述归纳了近5年(2018—2022年)农产品中轻、重元素稳定同位素在产地溯源和真伪鉴别方面的应用进展, 阐述了稳定同位素与其他技术相结合溯源的研究, 并依据判别结果得出结论: 增加采样数量、扩大采样范围、筛选有效溯源指标、选取适当的化学计量学方法, 同时利用多种分析技术融合鉴别, 从而提高溯源正确率, 完善农产品溯源体系, 为稳定同位素今后的研究提供参考。     

Biohydrogen production: prospects and limitations to practical application

Hydrogen may be produced by a number of processes, including electrolysis of water, thermocatalytic reformation of hydrogen-rich organic compounds, and biological processes. Currently, hydrogen is produced, almost exclusively, by electrolysis of water or by steam reformation of methane. Biological production of hydrogen (Biohydrogen) technologies provide a wide range of approaches to generate hydrogen, including direct biophotolysis, indirect biophotolysis, photo-fermentations, and dark-fermentation. The practical application of these technologies to every day energy problems, however, is unclear. In this paper, hydrogen production rates of various biohydrogen systems are compared by first standardizing the units of hydrogen production and then by calculating the size of biohydrogen systems that would be required to power proton exchange membrane (PEM) fuel cells of various sizes.     

响应面法优化刺参(Apostichopus japonicus)中金刚烷胺检测

目的利用响应面分析法优化刺参中金刚烷胺的检测。方法在单因素基础上,确定采用1%乙酸乙腈作为提取溶剂,以1%乙酸乙腈的添加量、超声时间、PSA吸附剂的添加量、C_(18)吸附剂的添加量为影响因素,以金刚烷胺的回收率为响应值,根据Box-Behnken试验设计原理对刺参中金刚烷胺提取条件进行响应面分析,优化前处理条件。结果1%乙酸乙腈为15 mL,超声提取10 min, PSA吸附剂为250 mg时刺参中金刚烷胺的回收率最大。在此优化条件下进行验证性试验,测得金刚烷胺的回收率为118%,与预测值相对误差为9.62%。实际检测刺参样品20个,2个样品检出,分别为4.3、1.6μg/kg。结论该优化前处理方法具有良好的可行性。     

River run: an interactive GIS and dynamic graphing website for decision support and exploratory data analysis of water quality parameters of the lower Cape Fear river

To visualize the water quality of the Lower Cape Fear River basin a Decision Support System (DSS) web site was developed which incorporates dynamic graphing and Geographic Information System (GIS) software. Together, these two software packages enable users to interact with water quality variables in order to investigate the spatial and temporal complexity of the data. The result of this research is that graphing and GIS technology are capable of being implemented over the Internet and that complex water quality data can be successfully disseminated using this medium. However, there remains a need to seamlessly link the graphing and GIS software which will make the visualization tools much more successful at communicating the complex spatial and temporal data.     

褐藻胶的降解方法及其产物生物活性研究进展

褐藻胶是褐藻中含有的酸性多糖,由β-D-甘露糖醛酸及其C5差向异构体α-L-古罗糖醛酸两种单体组成。经降解后的小分子寡糖具有增强植物抗逆性、促进生长作用、抗菌活性、抗肿瘤活性、抗炎活性以及抗氧化活性等多种生理活性。目前,褐藻胶寡糖制备的方法主要有化学降解法、物理降解法和生物降解法。本文概述了褐藻胶结构、褐藻胶降解方法以及褐藻胶寡糖生理活性研究现状,其中重点介绍了生物降解的方法,并对褐藻胶裂解酶及其降解产物的应用进行了展望。