环境水样中痕量铜的浊点萃取-火焰原子吸收光谱测定法

目的建立环境水样中痕量铜的浊点萃取(cloud point extraction,CPE)-火焰原子吸收光谱(flame atomic absorption spectrometry,FAAS)测定法。方法样品在p H 9.5的条件下,加入0.4 ml的1 mmol/L 2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(5-Br-PADAP)溶液,0.1%氯化钙溶液0.1 ml,5%(W/V)Triton X-114溶液0.8 ml,40℃加热15 min后离心,采用火焰原子吸收光谱法进行检测。结果在2~240μg/L的线性范围内,所得回归方程为A=0.002 7c+0.024 6,r=0.995 8。以3倍信噪比计算,方法的检出限为0.62μg/L,富集倍数为36.58倍,平均加标回收率为96.28%~98.08%,RSD为1.67%~3.13%。结论该方法简单、灵敏,具有良好的重现性,适用于环境水样中痕量铜的测定。     

16种植物挥发油对柏子仁黄曲霉菌的抑制作用考察

目的:从16种植物(香茅、香叶、松节、山苍子、薄荷、干姜、丁香、姜黄、红花椒、肉桂、罗勒、迷迭香、青花椒、竹叶花椒、八角茴香、肉豆蔻)挥发油中筛选出对黄曲霉菌生长有较好抑制效果的植物挥发油。方法:采用平板培养法从柏子仁药材表面分离得到黄曲霉菌,利用水蒸气蒸馏法提取16种植物挥发油,采用滤纸片熏蒸后测定黄曲霉菌的菌落直径,对16种植物挥发油抑制黄曲霉菌生长的效果进行研究。结果:采用性状、显微及DNA条形码鉴定的方法从柏子仁药材上成功分离了黄曲霉菌,上述16种植物挥发油对黄曲霉菌的抑菌率分别为2. 93%,0. 05%,0. 37%,76. 07%,0. 34%,0. 15%,50. 05%,8. 51%,1. 43%,58. 20%,0. 07%,2. 60%,8. 73%,100. 00%,52. 62%,0. 07%。结论:16种植物挥发油对黄曲霉菌均有着不同程度的抑菌活性,其中竹叶花椒挥发油、山苍子挥发油、肉桂挥发油的抑菌效果较好,可为柏子仁生长储藏过程中防治黄曲霉菌的污染提供参考,并为植物挥发油作为中药仓储过程中的抑菌剂提供应用依据。     

基于荧光定量PCR技术的当归不同炮制品中大肠埃希菌数量测定方法开发及比较研究

目的对当归不同炮制品中大肠埃希菌变化进行定量分析。方法建立荧光定量PCR方法,对当归不同炮制品、不同产地、不同收集企业、不同储藏时间的大肠埃希菌进行定量分析。结果不同炮制品中大肠埃希菌数量变化为生当归土炒当归酒当归;在不同产地的当归中以甘肃岷县地区所含的大肠埃希菌的数量最少;与零售企业相比,生产销售企业的当归和酒当归中大肠埃希菌的数量较少;不同储藏时间对当归和酒当归中大肠埃希菌数量有一定影响,随储藏时间的增加,大肠埃希菌的数量也在增加。对部分代表性样品进行平板计数法与荧光定量PCR法比较时发现,平板计数法结果多呈阴性,荧光定量PCR结果均呈阳性。结论所建立的荧光定量PCR法特异性、灵敏度、可靠性以及报告周期均优于平板计数法,可为当归不同炮制品中大肠埃希菌的快速、准确定量检测提供有效手段。     

Revisiting the Hydrogen Storage Behavior of the Na-O-H System

Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS) experiments of NaH-NaOH composites reveal two principal features: Firstly, an H₂ desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH) and hydridic hydrogen (in NaH) important in the dehydrogenation mechanism, but that also an intra-phase H^δ+… H^δ– interaction may be a crucial step in the desorption process.     

Heteroepitaxy of Cerium Oxide Thin Films on Cu(111)

An important part of fundamental research in catalysis is based on theoretical and modeling foundations which are closely connected with studies of single-crystalline catalyst surfaces. These so-called model catalysts are often prepared in the form of epitaxial thin films, and characterized using advanced material characterization techniques. This concept provides the fundamental understanding and the knowledge base needed to tailor the design of new heterogeneous catalysts with improved catalytic properties. The present contribution is devoted to development of a model catalyst system of CeO₂ (ceria) on the Cu(111) substrate. We propose ways to experimentally characterize and control important parameters of the model catalyst—the coverage of the ceria layer, the influence of the Cu substrate, and the density of surface defects on ceria, particularly the density of step edges and the density and the ordering of the oxygen vacancies. The large spectrum of controlled parameters makes ceria on Cu(111) an interesting alternative to a more common model system ceria on Ru(0001) that has served numerous catalysis studies, mainly as a support for metal clusters.     

Effect of catalase supplementation in storage media for avulsed teeth

Abstract – The type of liquid medium used to store avulsed teeth prior to replantation has been shown to affect the long‐term prognosis. One possibility is that some storage media contain hydrogen peroxide (H₂O₂) that may be toxic to periodontal ligament cells. Therefore, the aim of this study was to determine if the addition of catalase to storage media improved the prognosis of replanted dog teeth. Forty‐eight mongrel premolar roots were endodontically treated, extracted, randomly divided and placed into one of four storage media: Hank's balanced salt solution (HBSS), containing no antioxidant); Viaspan, containing the antioxidant, glutathione, or the same two media supplemented with catalase(100 U ml^?1) for 1, 5, or 26 h prior to replantation. After 2 months, the dogs were euthanized and the roots histologically examined to evaluate the attachment tissues. Regardless of the storage medium used, overall healing was excellent and only 4% of the roots displayed inflammatory or replacement resorption. When roots from the different storage media were compared, those stored in HBSS were found to display the highest incidence of surface resorption (55.7%). Supplementation of HBSS with catalase resulted in a lower level of surface resorption (48.6%) that was statistically significant (P < 0.05). Roots stored in Viaspan – or + catalase displayed even lower levels of surface resorption (41.3 and 38.2%, respectively). The improvement observed with catalase‐supplemented HBSS was confined to the 45‐min incubation period; only Viaspan – or + catalase reduced surface resorption at the 5‐ and 26‐h incubations. Collectively, these data demonstrate that roots stored in media containing antioxidant activity undergo less surface resorption. These results suggest that low levels of H₂O₂ in storage media for avulsed teeth may adversely affect periodontal ligament cells.     

青菜的保鲜贮藏研究

目的 :延长青菜在冷藏条件下的贮藏期 ,解决海军舰艇冷藏库蔬菜贮藏期短的问题。方法 :使用塑料袋、纸箱、塑料筐为包装材料 ,塑料袋内充O3 负离子对青菜在 2℃和 9℃条件下进行保鲜贮藏。结果 :2℃条件下塑料袋包装青菜贮藏期延长至 2 5d ,腐烂率小于 5 .9%。结论 :使用塑料袋包装青菜 ,适宜的贮藏温度为 2℃。     

溶酶体保护蛋白/组织蛋白酶A基因敲除小鼠听力和耳形态学初步研究

目的研究溶酶体保护蛋白/组织蛋白酶A(protective protein/cathepsin A,PPCA)基因敲除小鼠听功能和耳形态学改变,探讨半乳糖唾液酸沉积症听力损害的病理生理机制。方法应用听性脑干反应(ABR)测试和颞骨连续切片,观察1月和2月龄的PPCA基因敲除纯合子(PPCA-/-)小鼠ABR反应阈和光镜下外耳、中耳及内耳形态改变,并以野生型(PPCA / )小鼠作对照。结果1月龄PPCA-/-小鼠ABR反应阈和耳形态无明显改变;2月龄时,短声和短音8、163、2 kHz反应阈较PPCA / 提高40~45 dB SPL,中耳黏膜增厚、听骨细胞囊泡化、变形和关节腔融合,血管纹增厚、螺旋神经节细胞、螺旋缘纤维细胞、前庭膜、基底膜及沿前庭阶外淋巴隙的间皮细胞囊泡化,但Corti器毛细胞及支持细胞正常。结论溶酶体保护蛋白/组织蛋白酶A缺乏可导致听力损害、中耳及耳蜗形态改变、中耳炎、听骨改变以及耳蜗螺旋神经节、血管纹、螺旋缘、前庭膜和基底膜等细胞的溶酶体储积,可能分别是传导性聋和感觉神经性聋的形成机制。     

原发性肉碱缺乏致脂质沉积性肌病的临床与病理特点

目的 分析原发性肉碱缺乏致脂质沉积性肌病（LSM）的临床与病理特点。方法 回顾性分析4例可能LSM患者的临床资料。结果 本组患者为亚急性或慢性起病，主要表现为近端肌无力，疲劳不能耐受；血清肌酶有不同程度的升高；肌电图示肌源性损害；病理检查示肌纤维内可见大量细小空泡和裂隙形成；MGT染色无破碎红纤维，油红O染色显示空泡为大量脂滴充填；受累纤维以Ⅰ型纤维为主。电镜证实肌纤维内脂滴堆积，可伴有线粒体的轻度增多。改善能量和糖皮质激素治疗有效。结论原发性肉碱缺乏致LSM是一种以易疲劳和肌无力为主要临床表现的脂质代谢障碍性肌病，病理改变以肌纤维内脂滴堆积为主，一般不伴有线粒体结构的明显异常。糖皮质激素治疗可获得良好疗效。