尼日利亚纳萨拉瓦州市售灌木芒果、腰果、秋葵、芝麻和高粱的真菌毒素污染情况研究（网络首发、推荐阅读）

采用LC-MS/MS真菌毒素检测法,对尼日利亚纳萨拉瓦州市场出售的食物作物（灌木芒果（n=12）、烤腰果（n=12）、干秋葵（n=12）、芝麻（n=35）、高粱（n=36））进行了分析研究。结果显示具致肝癌性黄曲霉毒素B1在灌木芒果、干秋葵和高粱样品中检出率分别为42%、25% 和19%,其平均浓度分别为19.2、8.27和4.75 µg/kg,伏马毒素B1污染了9%的芝麻样品（平均浓度为12.5 µg/kg）和47%的高粱样品（平均浓度为461 µg/kg）;同时受到黄曲霉毒素 B1和伏马毒素B1污染的高粱样本至少有19%。灌木芒果、高粱和干秋葵中检测到了具致肾毒性的赭曲霉毒素A,这是首次在干秋葵中报道检测到该毒素。可见,当地市场出售的这些食物作物受到真菌毒素的污染,可能威胁消费者的健康,需要采取积极措施防控污染。     

酶法水解牦牛皮蛋白制备抗氧化肽工艺的优化

以牦牛皮为原料,用碱性蛋白酶水解牦牛皮蛋白制备抗氧化肽。以水解度和牦牛皮蛋白水解物对DPPH自由基清除率的IC₅₀值为评价指标,在单因素实验的基础上,结合响应面（Box-Behnken）试验设计筛选出牦牛皮抗氧化肽的最佳制备工艺。结果表明,最佳制备工艺为:水解温度51 ℃,酶用量10890 U/g,水解时间10.6 h,pH8.5,底物浓度5%,此时水解度为41.39%±0.69%,牦牛皮抗氧化肽清除DPPH·、ABTS+·、·OH的IC₅₀值分别为2.884、2.110、2.523 mg/mL。综上,该制备工艺下的牦牛皮抗氧化肽对自由基有良好的清除能力,且有较强的还原能力,说明牦牛皮抗氧化肽有望作为天然抗氧化剂得到开发利用。     

Polyester-polyether block copolymers. I. Wide-angle X-ray diffraction studies of poly(hexamethylene terephthalate)/poly(oxytetramethylene) and related block polymers

The crystallisation and orientation of the individual structural components of poly(hexamethylene terephthalate)/poly(oxytetramethylene) block copolymers have been studied by wide-angle X-ray diffraction. The crystallisation behaviour in the unstretched state is determined by the proportions and molecular weights of the polyether blocks. For copolymers containing less than 60 wt% of polyether of m. w. ≯ 2000, only the polyester segments crystallise spontaneously, but with polyether m. w > 2000 two crystalline phases are formed. Similar behaviour was found in block polymers from other readily crystallising polyesters, but with non-crystallising polyesters the polyether segments crystallised spontaneously. Moderate tensile deformation of the block copolymers from polyether of m. w. 2000 leads to the stress-reversible highly oriented crystallisation of the polyether whilst the polyester remains undeformed. At higher extensions, irreversible orientation of the polyester segments occurs. The observations suggest that the polyester and polyether segments form discrete regions since otherwise homogeneous crystallisation should occur.     

Recovery of fatty acids by immobilized solvent extraction

The use of silicone rubber tubes swollen with solutions of TOPO (trioctyl phosphine oxide) in kerosene as membranes for the recovery of fatty acids from anaerobic digesters was investigated. The flux of acetic and propionic acids was found to increase with the concentration of TOPO when the concentration was low. At very high TOPO concentrations, the flux decreased indicating the existence of an optimum TOPO concentration. The relationship between the flux and concentration of unionized propionic acid did not agree with that expected for pure diffusion. This was due to the reversible reaction between TOPO and propionic acid in the membrane. The flux of propionic acid was measured as a function of time for new membranes and for membranes removed from storage. Rather long times, 70 to 300 hours, were required to achieve steady acid fluxes. This time was required to fully develop the concentration profiles within the membranes.     

Effect of the Crystallization Process and Solid State Storage on the Physico-Chemical Properties of Scale-Up Lots of CI-936

N-(2,2-diphenylethyl)adenosine, designated as CI-936, is a novel, orally active antipsychotic agent. Depending on the manufacturing process, the drug substance exists in more than one crystalline form. Three lots of the drug were characterized by thermal analysis, scanning electron microscopy, X-ray diffraction, and dissolution. Two of these lots were found to be crystalline while the third was amorphous. The physical properties of the crystalline forms appear to change during storage under ambient conditions. The amorphous form, inspite of being in a high energy state, was not affected by storage. The absolute bioavailability of the amorphous form in dogs is more than 90%. In contrast, the other two crystalline lots demonstrated lower and unpredictable oral absorption profiles.