Mycotoxin contamination in corn smut (Ustilago maydis) galls in the field and in the commercial food products

Corn infected with Ustilago maydis, causal agent of common smut disease, produces galls that are used as food in certain cultures, but may be contaminated with mycotoxins. The objective of this study was to determine mycotoxin levels in common smut galls (CSGs) collected from the field at corn ear reproductive stages R1 through R5 and in commercial CSGs products. The study was conducted in 2012 and 2013. A simple extraction method for five mycotoxins was devised and the results showed the presence of these compounds in CSGs in corn during ear development at various physiological stages. Fumonisin was the major mycotoxin in CSG samples in both 2012 (63%, ≤150.7 μg g⁻¹) and 2013 (46.9%, ≤20.9 μg g⁻¹); followed by aflatoxin (2012: 2%, ≤14.7 ng g⁻¹; 2013: 30.6%, ≤10.8 ng g⁻¹) and zearalenone (2012: ≤41.70 ng g⁻¹; 2013: ≤12.40 ng g⁻¹). Deoxynivalenol (DON) was only detected in 2012 (≤1.6 μg g⁻¹), and cyclopiazonic acid was only detected in 2013 (≤3.18 μg g⁻¹). Commercial canned and fresh CSG samples also contained detectable amounts of mycotoxins including aflatoxin, fumonisin, CPA, and DON. Aspergillus flavus was isolated from selected 2013 CSG field samples at R2 or older (0–1.6 × 10⁶ cfu/g), whereas Fusarium spp were isolated at R1 or older (0–7.5 × 10⁷ cfu/g). These results indicate that CSGs can be infected with mycotoxigenic fungi and contaminated with mycotoxins. The incidence of mycotoxins in commercially available CSG products was highly variable and warrants further study.     

建构主义视野下的地方本科院校化工类专业实习策略探析

针对地方本科院校化工类专业实习存在的问题,在分析了建构主义学习理论及学习模式的优势基础上,按建构主义学习理论分析学生特征及化工实习内容特征,设计实习情境、资源、策略、管理与帮助、评价等内容,确定化工类专业实习目标,并且以有利于学生对知识和能力的主动建构为原则,提出了地方本科院校化工类专业实习的具体实施方案。     

Real-time and visual loop-mediated isothermal amplification: Efficient GMO screening targeting pat and pmi marker genes

Rapid and efficient screening assays based on loop-mediated isothermal amplification (LAMP) were developed, targeting two marker genes, namely, phosphinothricin-N-acetyltransferase (pat) and phosphomannose isomerase (pmi). These marker genes are being employed in more than 35% of GM events approved globally. Specificity of developed visual and real-time LAMP assays was confirmed using seven GM events of two crops, viz., maize (3272, 59122, Bt11, Bt176, MIR604, TC1507), and cotton (Widestrike™). In visual LAMP, positive amplification can be directly analyzed by the colorimetric change from orange to green, whereas real-time LAMP is based on the monitoring of fluorescence signals as amplification and annealing curves. Visual LAMP was found sensitive enough to detect up to 0.05% GM content for pat and 0.1% for pmi within 40 min. Real-time LAMP efficiently detected up to 0.01% GM content within 30 min. Practical applicability of developed assays was confirmed using proficiency test samples of maize. LAMP assays for pmi gene have been reported for the first time. Due to portability of systems, the developed LAMP assays when combined with a fast DNA extraction method could facilitate on-site GMO screening.     

ICP-AES法同时测定水牛奶中钙、镁、磷、铁和锌

目的 建立用微波消解、电感耦合等离子体发射光谱法同时测定水牛奶中的钙、镁、磷、铁和锌的方法。方法 采用硝酸、过氧化氢作溶剂, 用微波方法消解水牛奶样品, 样液定容后, 采用电感耦合等离子体发射光谱法测定水牛奶试液中钙、镁、磷、铁和锌。测定时选择波长为317.993{106}、202.582{466}、178.284{489}、238.204{141}和213.856{457}光谱线分别作为Ca、Mg、P、Fe、Zn分析线。结果 钙、镁、磷、铁、锌检出限分别为0.091、0.063、0.037、0.019、0.012 mg/L, 加标回收率为94.7%~108.2%, 相对标准偏差 (RSD, n=11) 均小于2.5%。结论 本方法分析结果与国标方法测定值相符, 具有重复性好、消解用试剂量少、操作简单、检测速度快、多元素同时测定、减少环境污染等优点。     

淀粉物态性质分析中DSC的应用

文章主要讨论利用DSC研究变性淀粉微晶熔融性质和淀粉变性程度，淀粉糊化与老化过程的热力学性质。结果显示，DSC在淀粉物态性质分析中具有广泛的适用性。     

Synthesis and characterization of NTS material and its oxidation desulfurization properties

The development of desulfurization technology involving the onsite direct generation of hydrogen peroxide (H₂O₂) from H₂ + O₂, followed by H₂O₂ oxidation to organic oxides without conventional refining is regarded as one promising approach for reducing capital and operating costs. The objective of our research is to provide bi-functional catalytic materials based on a combined process for the oxidative desulfurization (ODS) using H₂O₂ in situ generated. We have prepared a series of new bi-functional titanosilicate (NTS, titanium silicalite combined with noble-metal loading), which have been synthesized by combining noble-metal sources with modified titanium silicalite under basic conditions. Here, the synthesis and characterization of NTS samples, and their ODS properties are presented. The samples were characterized by various analytical techniques, and their direct ODS performances were investigated. The results indicate that NTS shows well ordered MFI topology and with hollow structure; NTS combined with noble-metal shows potential for application in direct ODS with H₂ + O₂ in one-step process.     

β-B-BiW_9O_(33)夹心型铋(Ⅲ)钨酸盐的合成、结构及量子化学计算

在常规条件下合成了2个具有一维链状结构的夹心型多金属铋钨酸盐Na10{[(M(H2O)3)2(WO2)2(BiW9O33)2]}·21·5H2O(M=NiⅡ,ZnⅡ),并通过X射线单晶结构分析、元素分析、红外光谱对晶体进行表征.文章还对化合物进行了量子化学计算,用于说明结构特征.     

Snapback breakdown ESD device based on zener diodes on silicon-on-insulator technology

An Electrostatic Discharge (ESD) device with snapback breakdown property based on two abreast PN junctions with different reverse breakdown voltages is proposed. The proposed device can be implemented with conventional epitaxial silicon substrate with traditional VDMOS process, such that it can be applied to protect the dielectric layer under the gate of the transistor. The ESD protection characteristics of the proposed device can be easily adjusted by controlling the junction formation condition. The performance of the proposed device is validated by experimental measurements, which have shown to be able to withstand >2 kV ESD protection voltage consistently. The layout dependence of the proposed structure is also investigated.