可视化LAMP法快速检测转基因苜蓿草J101品系

目的建立我国农业部未颁发农业转基因生物安全证书的转基因苜蓿草J101品系特异性环介导等温扩增(loop–mediated isothermal amplification,LAMP)检测方法。方法根据转基因苜蓿草品系J101 3’端外源插入片段与苜蓿草基因组DNA之间的邻接区序列设计6条引物,建立转基因苜蓿草J101品系特异性LAMP检测方法,并对本方法的特异性、灵敏度进行了测定。结果建立的检测方法特异于转基因苜蓿草J101成分检测,检测最低DNA浓度为(1imit of detection,LOD)为16 pg,相当于10拷贝转基因苜蓿草J101基因组DNA。结论本研究建立的转基因苜蓿草J101品系特异性LAMP检测方法特异性好,灵敏度高,能够快速、准确、稳定地对转基因苜蓿草J101成分进行检测分析。     

自动顶空气相色谱法测定芒果浆中 乙烯利的残留量

目的建立芒果浆中乙烯利残留量的自动顶空气相色谱法检测方法。方法将芒果浆样品加入顶空样品瓶中,加入适量饱和氢氧化钾溶液,在80℃的条件下恒温加热,氢火焰检测器检测产生的乙烯含量,外标法定量。结果乙烯利在0.5~100.0μg/m L浓度范围内线性关系良好,相关系数均大于0.9999。添加水平为0.02、0.05、0.10 mg/kg时,乙烯利的平均回收率分别为79.9%、85.4%和86.8%,相对标准偏差为3.97%~5.26%。结论该方法简便、快速、经济实用,适用性强,结果准确可靠,可用于样品批量快速检测。     

防紫外线纺织品的现状及发展趋势

叙述了防紫外线屏蔽剂、防紫外线纺织品生产方法、纺织品防紫外线性能影响因素及防紫外线性能测试的研究现状,预测了防紫外线织物的三种发展趋势。     

近红外光谱测定不同鲜肉肉糜中蛋白质含量

采集4 000~10 000cm~(-1)波数范围内210份鲜肉(牛、羊、猪肉各70份)为校正集样品光谱数据,在不同的光谱预处理基础上,用偏最小二乘法(partial least squares,PLS)建立了单独的不同种类肉品,及其混合鲜肉肉糜红外光谱与蛋白质测量值之间的定量分析模型。90份鲜肉(牛、羊、猪肉各30份)为预测集样品,采集光谱数据后用于模型的验证。结果表明:鲜肉建模集及预测集相关系数分别为0.954,0.929;RMSEC及RMSEP分别为0.495,0.669。该模型能够很好地实现鲜肉蛋白质含量的快速测定,提高了模型预测的广适性。     

氯化浸取钢渣中钒的动力学研究

为了提高湿法浸出低钒钢渣中钒的浸出率,并为湿法浸出低钒钢渣中钒提供理论依据,从动力学角度分析整个浸出过程,并考察温度、液/固比、浸出时间和搅拌速度对浸出过程的影响。结果表明,在90℃,液/固比为10:1以及4.0mol/L盐酸,过氧化氢8.0mL,浸取90min条件下,低钒钢渣中钒的浸出率可达到98.8%。通过正交实验和动力学推导,得到描述浸出过程的经验方程。低钒钢渣湿法浸出钒的动力学模型为未反应收缩核模型,浸出过程的表观活化能为7.21kJ/mol。该模型表明浸出过程中的控制步骤取决于边界层的扩散速度。提高温度、液/固比和浸出时间,均可增加钒的浸出速度,提高钒的浸出率。     

Modelling mould spoilage in cold-filled ready-to-drink beverages by Aspergillus niger and Penicillium spinulosum

Mathematical models have been developed to predict the probability of growth of spoilage moulds in response to various preservative systems in ready to drink beverages. A Box-Behnken experimental design included five variables, each at three levels: pH (2·8, 3·3, 3·8), titratable acidity (0·20%, 0·40%, 0·60%), sugar content (8·0, 12·0, 16·0 °Brix), and preservative concentrations (sodium benzoate and potassium sorbate, each 100, 225, 350 ppm). Duplicate samples were inoculated with a mould cocktail consisting of equal proportions of Aspergillus niger and Penicillium spinulosum spores (5·0×10⁴spores/ml). The inoculated samples were plated on malt extract agar after 0, 1, 2, 4, 6, and 8 weeks. Logistic regression was used to create predictive models. The pH, titratable acidity, sugar content, sodium benzoate, and potassium sorbate levels were all found to be significant factors in predicting the probability of mould growth over time. Interactions between pH and sodium benzoate, pH and potassium sorbate, and pH and sugar content were also statistically significant. This logistic model was validated against 14 new conditions and predicted the growth of mould after 8 weeks with over 96% accuracy. Product developers can use these models to predict mould growth in ready to drink beverages.     

推荐一个高职精细有机合成项目化教学实验——对硝基苯甲酸的制备

推荐一个高职精细有机合成项目化教学实验-对硝基苯甲酸的制备,以重铬酸钠-硫酸为氧化剂,以对硝基甲苯为原料加热回流60 min,然后通过碱洗除去反应体系里的铬盐,粗产物用乙醇—水重结晶可得较好收率的对硝基苯甲酸浅黄色片状结晶。通过实验可以让学生掌握重铬酸盐-硫酸氧化的基本原理和回流、抽滤、重结晶等基本操作以及固体酸性物质的纯化方法。     

Syntheses,structures and photocatalytic properties of two coordination polymers based on bis(1,2,4-triazol-4-ylmethyl)benzene and multicarboxylates

Two coordination polymers {[Cu₄(OH)₂(btrb)₂(btc)₂]·4H₂O}_n (1) and {[Cd₂(btrb)(adc)₂(H₂O)]·H₂O}_n (2) were synthesized with hydrothermal method and characterized (btrb = 1,4-bis(1,2,4-triazol-4-ylmethyl)benzene, btc = 1,3,5-benzenetricarboxylate, adc = 1,3-adamantanedicarboxylate). 1 shows an unusual (3,10)-connected two-dimensional metal–organic framework based on the tetranuclear copper(II) cluster [Cu₄(μ₃-OH)₂]. 2 is an interesting three-dimensional network based on the one-dimensional metal–organic nanotube. 1 shows good photocatalytic activity for the degradation of methyl blue (MB). The luminescence of 2 was investigated.     

织物尺寸变化率测试方法的分析与研究

分析了现有织物尺寸变化率的测试方法,提出了采用图像处理技术对手工测量织物尺寸变化率的测试方法进行改进。对图像法测试织物尺寸变化时织物的标记提出了快速标记方法和精密标记方法,并对这两种标记方法的测试指标进行了确定,提出了精确测量织物尺寸变化时的3个新指标,即收缩均匀性、收缩幅度和收缩形态。     

固相微萃取- 气相色谱法测定浓缩苹果汁中的8 种有机磷农药残留

采用固相微萃取技术测定浓缩苹果汁中有机磷农药残留量,对固相微萃取条件进行了选择。结果表明,本法的回收率在69.2%～103.2% 之间,相对标准偏差在0.98%～4.8% 之间,8 种有机磷最低检出浓度为0.4～4.1ng/L。