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91.
Agnieszka Zapanik Marcin Brya Agnieszka Wakiewicz Edyta Ksieniewicz-Wo
niak Grayna Podolska 《Molecules (Basel, Switzerland)》2022,27(1)
The aim of this study was to estimate the contamination of grain coffee, roasted coffee, instant coffee, and cocoa purchased in local markets with ochratoxin A (OTA) and its isomerization product 2′R-ochratoxin A (2′R-OTA), and to assess risk of dietary exposure to the mycotoxins. OTA and 2′R-OTA content was determined using the HPLC chromatography with immunoaffinity columns dedicated to OTA. OTA levels found in all the tested samples were below the maximum limits specified in the European Commission Regulation EC 1881/2006. Average OTA concentrations calculated for positive samples of grain coffee/roasted coffee/instant coffee/cocoa were 0.94/0.79/3.00/0.95 µg/kg, with the concentration ranges: 0.57–1.97/0.44–2.29/0.40–5.15/0.48–1.97 µg/kg, respectively. Average 2′R-OTA concentrations calculated for positive samples of roasted coffee/instant coffee were 0.90/1.48 µg/kg, with concentration ranges: 0.40–1.26/1.00–2.12 µg/kg, respectively. In turn, diastereomer was not found in any of the tested cocoa samples. Daily intake of both mycotoxins with coffee/cocoa would be below the TDI value even if the consumed coffee/cocoa were contaminated with OTA/2′R-OTA at the highest levels found in this study. Up to now only a few papers on both OTA and 2′R-OTA in roasted food products are available in the literature, and this is the first study in Poland. 相似文献
92.
独立高校数学课程的开设旨在让学生掌握数学知识的基础上,提高数学应用能力.然而现行的考核方式存在重考试结果,轻学习过程等问题.从传统考核方式入手,指出其不足之处,基于模糊综合评判法建立新型评价体系和数学模型,通过试点运行验证了新的考核方式的可行性、客观性、合理性和科学性. 相似文献
93.
课程实施是课程改革的关键环节,而中国的13亿人口,8亿在农村,所以关注农村中学新课程的实施情况,关系到课程改革的成败。本研究主要运用质性研究方法,辅以问卷调查,对影响农村初中化学新课程实施的影响因素进行了分析。 相似文献
94.
燃气透平叶片表面颗粒沉积特性数值研究进展 总被引:1,自引:0,他引:1
污染物颗粒在燃气透平叶片表面及冷却通道内的沉积将影响透平叶片的冷却特性和安全服役寿命。国外许多研究机构对燃气透平叶片表面污染物颗粒沉积特性及其与叶片气膜冷却的相互作用机制进行了持续研究。本文首次系统总结了近年来燃气透平叶片表面污染物颗粒沉积特性数值研究进展,重点介绍了燃气透平叶栅流道内污染物颗粒的沉积机制、颗粒沉积和脱离物理模型以及颗粒沉积与透平叶片冷却特性相互作用的数值模拟方法和研究成果。基于当前研究热点和发展趋势,结合作者的研究经历,指出了国内在研发先进燃气轮机透平冷却结构时应注意的问题和方向,为高效、燃料适应性更广的燃气轮机技术自主开发奠定基础。 相似文献
95.
《Current Applied Physics》2020,20(4):582-588
Energy storage system powered by renewable energies is a viable option to meet energy requirement without addition of carbon footprints to the environment. This study involves development of theoretical and computational models for a solar photovoltaic (PV) system coupled with a lead acid battery. The study commenced with selection of most appropriate lead acid battery and PV system for installation in a representative location in Riyadh, Kingdom of Saudi Arabia. Various technical and economic parameters were assessed and calculated by computational approach. The optimized lead acid battery was integrated with low concentration solar PV panels (CPV) followed by a feasibility study. Theoretical model was developed for the integrated system to calculate various parameters of the CPV and lead acid battery. Technical and economic assessment of this coupled unit was calculated using a theoretical approach. The developed model was then subjected to computational approach for verification and validation analysis of the integrated system. The detailed assessment of batteries and integrated system show the applicability of this system in Riyadh region. The research will be extended to develop energy storage systems for remote areas using lead acid batteries. 相似文献
96.
Thiamethoxam and its metabolite clothianidin residues pose a potential threat to human health. This study aims to investigate the residue behavior and acute dietary risk assessment of thiamethoxam and clothianidin on spinach. Thiamethoxam and clothianidin were extracted using a quick, easy, cheap, effective, rugged, safe (QuEChERS) method and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). At spike levels from 0.01 to 5 mg kg−1, the average recoveries of both analytes were in the range of 94.5–105.5%, with relative standard deviations (RSDs) of 3.8–10.9%. The dissipation behavior of thiamethoxam followed first-order kinetics, with half-lives of ≤1.6 days. Clothianidin appeared readily as a plant metabolite with highest level exhibited during 3 to 5 days after application. Temperature and light may be two main factors for degradation of thiamethoxam. Besides, acute risk assessment of thiamethoxam and clothianidin was evaluated with risk quotients (RQs) <100%, which suggested a low health risk for all consumer groups of Chinese residents. 相似文献
97.
98.
PANG Jie YE Bing-Hong HUANG Yong-Mei LIN Qiong ZENG Cui SUN Yuan-Ming 《结构化学》2007,26(8):924-928
In order to prove up the interaction between konjac glucomannan (KGM) and other amyloses, by using KGM, guaran gum and carrageenan as materials, their blending in different external conditions was modeled by means of molecular dynamics (MD) method. The result showed that 323 K was a significant turning point for the formation of hydrogen bond, and KGM and guaran gum were just juxtaposed together via intermolecular hydrogen bond; but with the addition of carrageenan, KGM, guaran gum and carrageenan were spirally twisted together, and when their blending proportion is 3:2:9 the combination was the most compact. Moreover, the research result has provided the sequent studies afterwards on amyloses with some references. 相似文献
99.
简要分析各种储氢材料和技术的基础上,重点介绍了高比表面积活性炭的制备方法,目前最常用的活化方法是以氢氧化钾为活化剂的化学活化法;并总结了近年来前人在高比表面积活性炭储氢方面的研究结果,同时简要分析了高比表面积活性炭储氢机理方面的研究进展. 相似文献
100.