Induction of oxidative stress and apoptosis by PFOS and PFOA in primary cultured hepatocytes of freshwater tilapia (Oreochromis niloticus)

Perfluorinated organic compounds (PFOCs) are emerging persistent organic pollutants (POPs) widely present in the environment, wildlife and human. We studied the cellular toxicology of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) on oxidative stress and induction of apoptosis in primary cultured hepatocytes of freshwater tilapia (Oreochromis niloticus). Cultured hepatocytes were exposed to PFOS or PFOA (0, 1, 5, 15 and 30 mg L-1) for 24 h, and a dose-dependent decrease in cell viability was determined using trypan blue exclusion method. Significant induction of reactive oxygen species (ROS) accompanied by increases in activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) were found, while activities of glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were decreased. Glutathione (GSH) content was reduced following treatment of PFOA and PFOS. A dose-dependent increase in the lipid peroxidation (LPO) level (measured as maleic dialdehyde, MDA) was observed only in the PFOA exposure groups, whereas LPO remained unchanged in the PFOS exposure groups. Furthermore, a significant activation of caspase-3, -8, -9 activities was evident in both PFOS and PFOA exposure groups. Typical DNA fragmentation (DNA laddering) was further characterized by agarose gel electrophoresis. The overall results demonstrated that PFOS and PFOA are able to produce oxidative stress and induce apoptosis with involvement of caspases in primary cultured tilapia hepatocytes. (c) 2007 Elsevier B.V. All rights reserved.

Hydrodynamics in an expanded bed of large size ion-exchange resin, and natural product adsorption

Successful applications of expanded bed adsorption (EBA) technology have been widely reported in the literature for protein purification. Little has been reported on the recovery of natural products and active components of Chinese herbal preparations using EBA technology. In this study, the hydrodynamic behavior in an expanded bed of cation resin, 001 x 7 Styrene-DVB, was investigated. Ephedrine hydrochloride (EH) was used as a model natural product to test the dynamic binding capacity (DBC) in the expanded bed. EBA of EH directly from a feedstock containing powdered herbs has also been investigated. These particles are different from commercially available expanded bed adsorbents by virtue of their large size (20S to 1030 gm). When the adsorbent bed is expanded to approximately 1.3 to 1.5 times its settled bed height, the axial liquid-phase dispersion coefficient was found to be of the order 10(-5) m(2) s(-1), which falls into the range 1.0 x 10(-6) to 1.0 X 10(-5) m(2) s(-1) observed previously in protein purification. Because of the favorable column efficiency (low axial dispersion coefficient), the recovery yield and purification factor values of EH directly from a feedstock reached 86.5% and 18, respectively. The results suggest that EBA technology holds promise for the recovery of natural products and active components of Chinese herbal preparations.

A small signal equivalent circuit model for resonant tunnelling diode

We report a resonant tunneling diode (RTD) small signal equivalent circuit model consisting of quantum capacitance and quantum inductance. The model is verified through the actual InAs/In0.53Ga0.47As/AlAs RTD fabricated on an InP substrate. Model parameters are extracted by fitting the equivalent circuit model with ac measurement data in three different regions of RTD current-voltage (I-V) characteristics. The electron lifetime, representing the average time that the carriers remain in the quasibound states during the tunneling process, is also calculated to be 2.09 ps.

Optimization of cubic GaN growth by metalorganic chemical vapor deposition based on residual strain relaxation

The reduction of residual strain in cubic GaN growth by inserting a thermoannealing process is investigated. It is found that the epilayer with smaller tensile strain is subject to a wider optimal "growth window." Based on this process, we obtain the high-quality GaN film of pure cubic phase with the thickness of 4 mum by metalorganic chemical vapor deposition. The photoluminescence spectrum at room temperature shows the thick GaN layer has a near-band emission peak with a full width at half maximum of 42 meV which confirms its high crystal quality, further supported by the x-ray (002) diffraction measurement. A simplified model is demonstrated to interpret this strain effect on the growth process. (C) 2003 American Institute of Physics.

印刷线路板废弃物的热解与动力学实验研究

分别应用管式炉反应器和热重分析手段对印刷线路板废弃物的热解行为和热解动力学进行了实验研究。在管式炉中，研究不同的热解温度：700～950℃，对产物分布和气体成分分布的影响。实验结果表明：PCB热解气体的主要成分是H2和CO2，气体的热值较低，仅为2.09～5.41MJ/m^3，PCB不适合以气体产物为目标的能源利用方式。应用Friedman方法对PCB的热解动力学进行了研究，求得PCB的热解动力学参数分别是：表观活化能190.92kJ/mol，反应级数5.97，指前因子lnA47.14min^-1。

菜花烙铁头蛇毒去整合素的纯化、克隆及活性研究

蛇毒去整合素蛋白（disintegrin）家族一般具有分子量低、富含半胧氨酸和含有RGD三肽等结构特点，因其能与配基竞争结合细胞表面的整合素受体，干扰整合素的正常功能而呈现出多方面的生物学活性，如抑制血小板聚集、抑制肿瘤转移和诱导细胞凋亡等。本论文用凝胶过滤、反向高压液相等层析技术从我国云南产菜花烙铁头（Trimeresurusjerdonii）蛇毒中分离纯化到两个新的去整合素蛋白，分别命名为jerdonin和Jerdonatin。MALDI-TOF-MS测定jerdonin分子量为7483Da，jerdonatin分子量为80llDa，二者均属第二类去整合素。分别测定了其N末端25个氨基酸序列，发现与其它蛇毒来源的去整合素具有很高的相似性。提取菜花烙铁头毒腺总mRNA，通过反转录PCR（RT-PCR）扩增到两个去整合素cDNA序列，分别命名为TJDIS-1和TJDIS-2。TJDIS-1全长1528bp，TJDIS-2全长16O3bp，二者均包含编码信号肚区、前肤区、金属蛋白酶区、间隔肤区和去整合素区一属于P一H型金属蛋白酶家族。经推导的氨基酸序列和MALDI一TOF一MS分析，可确定TJDIS-1去整合素区编码jerdonin，TJDIS-2去整合素区编码jerdonotin。jerdonin全长71个氨基酸，jerdonatin全长72个氨基酸，二者均含12个半眺氨酸，且在C末端附近均含有去整合素家族的典型特征三肤序列一RGD。氨基酸序列比较分析显示，jerdon加与来源于侏响尾蛇（Sistrurusm.tergeminus）的去整合素tergeminin序列相似性最高，为82.2％。而jertionatin与来源于黄绿烙铁头（Trimeresurusflavoviridis）的去整合素CTF-I序列相似性最高，为97.2％，仅在RGD附近有两个氨基酸不同。jerdonin与jerdonatin序列相似性为67.6％。本论文还研究了jedonin和jerdonatin的生物学活性。二者均能强烈抑制ADP、胶原、凝血酶诱导的人血小板的聚集，IC50为100-300nM。jerdonin和jerdonatin还能够抑制B16肿瘤细胞增生，研究表明，jerdonin不仅能显著抑制肿块的生长，还能延长荷瘤小鼠的寿命。平均肿块体积由对照的5260．33枷，降低至2086.65mm3，小鼠平均寿命由对照的24.8天延长至30.5天，提高了22.98％。本论文也研究了jerdonin和jedonatin对小鼠精卵受精过程的影响，结果表明jordonotin能够呈剂量关系抑制精卵结合，但对精卵融合无影响。当jerdonatin用量为10.0μg／毗时，单个卵子的精子结合数由对照的95.31降为21.83。菜花烙铁头蛇毒去整合素蛋白的结构和活性鉴定，为去整合素家族的生物多样性研究提供了丰富的素材，同时也为血栓、肿瘤、生殖等生理或病理过程的研究提供了一个有力的工具。

ENERGY-LEVEL CALCULATIONS OF THE RECONSTRUCTED 90-DEGREES PARTIAL DISLOCATION IN SILICON

An LCAO scheme taking into account 10 atomic orbitals (s-, p-, and d-type) applied to a supercell containing 256 atoms is used to calculate the bound states of the reconstructed 90-degrees partial dislocation in Si. The results differ significantly from our earlier calculations on the unreconstructed 90-degrees partial using the same method. We find two bands separate from each other in the entire Brillouin zone and the upper band penetrates deep into the indirect band gap which is in contradiction with the general opinion that core reconstruction clears the band gap of dislocation states.

富硅氮化硅薄膜的制备及其发光特性

采用射频磁控反应溅射法制备了氮化硅薄膜。利用X射线衍射谱（XRD）、红外光谱（IR）、能谱（EDS）和光致发光谱（PL）,通过与氮气中和空气中退火薄膜比较,对原沉积薄膜进行了成分与结构和发光特性研究。研究发现原沉积薄膜是部分晶化的富硅氮化硅薄膜,薄膜中晶态氮化硅颗粒的平均粒径为33nm;在氮气中退火后,纳米颗粒增大;在空气中退火后,薄膜被氧化,晶态颗粒消失。在4.67eV的光激发下,原沉积薄膜中观测到7个强的PL峰,其峰位分别为3.39,3.24,3.05,2.82,2.61,2.37和2.11eV。在氮气和空气中退火后,PL峰位和强度有变化。对其光致发光机制进行了探讨,认为硅悬挂键≡Si,氮悬挂键=N,硅错键≡Si-Si≡以及与氧有关的缺陷在富硅氮化硅薄膜高强度荧光发射中起主导作用。

黑土侵蚀区景观生态建设的水土保持效应

黑龙江省拜泉县是我国黑土侵蚀与综合治理的典型代表。经历了上世纪垦荒初期环境优美、土地肥沃，70年代后期水土流失严重、生态恶化，80年代以来大规模生态治理、环境明显改观的典型发展过程。是人类征服自然——自然报复人类——人类与自然和谐共处等人与环境关系演进的一个小小缩影。本论文以该典型区为研究案例，以景观格局——景观功能——景观生产力关系分析为研究思路，从遥感、统计资料、调查访问和取样实测等获得原始数据，运用景观指数和地理信息系统（GIS）等空间分析方法，结合通用土壤流失方程、地统计学和能值分析，综合评价了黑土侵蚀区景观尺度水土流失治理的区域土壤侵蚀控制效应、区域土壤性质恢复效应及大规模生态建设的农业效应。旨在为区域水土流失治理综合评价探索研究思路，也为该县或同类地区生态建设、环境保护及景观规划决策提供科学参考。本论文取得如下研究成果： (1). 经过多年来的大规模生态建设，拜泉县的生态环境有了明显的改观。区域景观类型数量和空间配置的变化对发挥其水土保持功能起到了很好的调控作用。从1989年到2002年，县域耕地面积减少24731hm2，林草地面积、水体面积分别增加了13568 hm2和1191 hm2，水库和塘坝增加1402座。全县55%的水土流失面积得到治理，82.2%的农田得到林网的防护，43.7%的景观地表超渗径流得到集蓄，土壤侵蚀模数由9.14 下降到6.50 。进一步的景观结构调整要注意增加林草地等类型斑块的聚集度；调节林网连接度、环度及网眼大小；增加水库塘坝的泻洪与灌溉配套设施等。 (2). 通过拜泉县双阳河流域30个子流域景观指数与土壤侵蚀模数的相关性分析，定量研究了景观结构和土壤侵蚀程度的关系。结果表明：农田面积百分比、景观聚集度与土壤侵蚀模数显著正相关，灌木林地和草地面积百分比、香农多样性指数与土壤侵蚀模数显著负相关。梯田、等高垄农田、顺坡垄农田、乔木林地、灌木林地、草地面积百分比，景观分维数、景观聚集度、景观香农多样性9个结构因子与土壤侵蚀模数的复相关系数（R=0.931）大于任一单因子相关系数，景观结构对土壤侵蚀的影响是多因子综合作用的复杂过程，且达到高度相关，9个结构因子与侵蚀模数之间存在线性回归关系。研究区平均土壤侵蚀模数为6.58 ，侵蚀强度较轻，但大于东北黑土区土壤容许流失量标准（2 ）。该流域是典型的农业景观，农田面积占景观总面积的71.8%，而且分布比较集中，它是未来土壤水蚀的主要景观要素，同时也是水土保持的主战场。增加灌草地斑块、实施农田保护性耕作等将是该流域继续控制土壤侵蚀的有效办法之一。 (3). 通过对拜泉县通双小流域土壤性状的空间变异性和空间相关性研究，得到下列结论：全碳、全氮、砂粒、粉粒、粘粒含量和容重具有中度的变异性，而砾石含量变异强烈，它能够表征该流域黑土的侵蚀强度。除砾石外，所有土壤性状之间具有显著的相关性 (P<0.05)。土壤性状主要与坡位、海拔高程和土地类型有关。全碳、全氮、粉粒和粘粒含量具有强度的空间自相关性，而容重和砂粒含量在空间上是中度自相关的。无论在农田，还是在整个流域，均有2/3左右的土地存在氮缺乏，容重和砂粒偏高的现象。地形、土地利用、侵蚀和侵蚀治理综合地影响了土壤性状的空间分异。但过去的土壤侵蚀是最突出的因子。侵蚀治理和土地类型调整在20-30年的尺度上，并没有显著地改善土壤的性质。目前的侵蚀治理对于土壤的移位和流失起到了很好的控制作用，但短期土壤质量恢复并不令人满意。如何提高土壤质量，将是又一迫在眉睫的任务。为了提高土壤质量，保护林地和草地不被破坏，改变农田的耕作方式等是该流域改善土壤性质的有效管理措施。 (4). 在拜泉县农业系统经济特征和生态建设动态分析的基础上，运用能值理论，研究了县域农业生态经济系统在大规模生态建设前后时间序列上的系统生产效率和可持续发展动态。主要结论如下：拜泉县经济发展与生态建设都取得了较大的成绩，但在县域生产生活大环境明显改善的情况下，农业系统自身的环境压力依然存在；农业系统的生产效率不高；农民生活水平较低；但大规模生态治理的农业效应已初步显现；系统的能值可持续发展有良好的趋向。

辽东次生林土壤呼吸及主要组分分离与量化

土壤呼吸是森林生态系统碳循环的重要组成部分，对土壤呼吸的主要组分根系呼吸和土壤微生物呼吸进行分离并量化，对于了解土壤碳释放规律、估算生态系统土壤碳的年际通量以及预测气候变化条件下根系或土壤微生物对土壤碳释放格局的影响具有重要意义。本文采用挖壕法测定辽东山区蒙古栎林、杂木林和胡桃楸林的土壤表面CO2通量，并同步分析土壤水热因子及土壤有机质、N含量、根系生物量、土壤酶活性、土壤微生物生物量等。研究结果表明：（1）辽东山区次生林0-10cm土壤有机质含量为9.29-18.15%，全氮含量为0.43-0.90%，pH值为5.67-6.19；次生林生长季细根生物量平均为152.61- 447.79 g/m2，粗根生物量平均为255.42-507.42 g/m2，根系总量平均为540.93-955.22 g/m2；土壤酶活性季节变化明显，且具垂直分布特征，蒙古栎林的土壤转化酶、淀粉酶和脱氢酶活性最高，胡桃楸林最低，胡桃楸林过氧化氢酶活性相对最大；土壤微生物量碳、氮的季节变化呈明显的单峰曲线并与土壤温度相关，土壤微生物量碳氮之间具显著相关性（P<0.05）。（2）次生林土壤总呼吸、根呼吸和土壤微生物呼吸具明显的日、季变化规律，生长季根呼吸贡献相对较低，胡桃楸林根呼吸贡献率为34.0-34.8%，蒙古栎林为17.9-28.4%，杂木林为14.7-35.3%；土壤微生物呼吸贡献率为66.0-85.3%，高于根呼吸贡献率，说明辽东山区次生林土壤微生物呼吸决定土壤总呼吸的变化趋势。（3）土壤呼吸与地下5cm土壤温度呈指数函数关系，土壤总呼吸的Q10值为1.29-2.30，微生物呼吸的Q10值为1.28-2.09，根呼吸的Q10值为1.29-3.72；土壤总呼吸、微生物呼吸、根呼吸与土壤含水量均无明显相关关系；蒙古栎林根呼吸与细根生物量显著相关，杂木林根呼吸与粗根生物量及根系总生物量显著相关，胡桃楸林根呼吸与根系生物量总量显著相关（P<0.05）；微生物呼吸与淀粉酶、转化酶、脱氢酶、过氧化氢酶均无显著相关性（除胡桃楸林与过氧化氢酶显著相关）；微生物呼吸与土壤微生物量碳、氮均呈显著线性相关关系（P<0.05）。（4）蒙古栎林土壤总呼吸、根呼吸、土壤微生物呼吸年际碳释放量分别为572.78、147.78和425.59 g C m-2a-1，杂木林分别为403.12、108.92、297.51 g C m-2a-1，胡桃楸林分别为519.47、173.75、345.72 g C m-2a-1；生长季和非生长季通过根呼吸释放的碳量均小于分解土壤有机质的微生物呼吸释放的碳量，非生长季次生林土壤碳释放量为39.21-152.04 g C m-2a-1，占全年呼吸总量的10-29%，说明冬季土壤碳释放量不能忽略。

西藏产雪莲花的化学成分研究

本学位论文报道了作为传统藏药材广泛使用的西藏产雪莲花化学成分的研究。论文由五章组成，第一章是三种西藏产雪莲花的化学成分的系统分离纯化和结构鉴定；第二章为西藏产雪莲花化学成分的液-质及串联质谱联用分析；第三章提出了以HPLC和TLC为检测方法的雪莲花药材质量标准草案；第四章给出了对西藏产雪莲花挥发油化学成分的气-质联用分析结果；第五章概述了雪莲花的化学成分及药理研究进展。 第一章包括三个部分。第一部分报道了绵头雪莲花(Saussurea laniceps Hand.-Mazz.)全草乙醇提取物化学成分的分离鉴定。采用正相硅胶柱层析及凝胶柱层析等分离方法，从西藏产绵头雪莲花的乙醇提取物中共分离鉴定出15个化合物。其中11个化合物为首次从该植物中分离得到，当中2个化合物系在凤毛菊属植物中首次发现。第二部分报道了水母雪莲花(Saussurea medusa Maxim.)全草乙醇提取物的化学成分。采用正、反相硅胶柱层析及凝胶柱层析等分离方法，共分离鉴定出15个化合物，其中1个为新化合物，另有4个化合物为首次从该植物中分离得到。新化合物结构通过质谱和一维及二维核磁共振等波谱解析方法及碱水解反应确定为巴豆酰基-高车前苷(M-7)。第三部分报道了三指雪莲花 (Saussurea tridactyla Sch.-Bip. ex Hook. f.)全草乙醇提取物的化学成分。采用正相硅胶柱层析及凝胶柱层析等分离方法，共分离鉴定出7个化合物，其中1个化合物为首次从该植物中分离得到。 第二章也包括三个部分。首先是采用液-质联用(HPLC-DAD-ESI-MSn)分析方法，对7个西藏不同产地的三指雪莲花化学成分进行了分析，通过与标准品的 UV和MS数据比较，共鉴定出14个峰，并对其中8个共有成分进行了定量测定。其次是关于八种西藏产雪莲花化学成分的液-质联用(HPLC-DAD-ESI-MSn)分析，通过与标准品的UV和MS数据比较，共鉴定出15个峰，并对其中8个共有成分进行了定量检测。最后通过对八种西藏产雪莲花主要化学成分的多级串联质谱(ESI-MSn)分析，快速、灵敏地鉴定出10个黄酮和3个香豆素化学成分。 第三章同样包括三个部分。首先是以绵头雪莲花中主要香豆素成分东莨菪素和伞形花内酯为对照品，通过TLC定性检测和HPLC含量测定，草拟出较严谨的药材质量标准。其次是将绵头雪莲花、三指雪莲花和雪兔子作为一个药材看待，草拟了以东莨菪素和伞形花内酯的TLC检测为指标的药材质量标准。最后是针对水母雪莲花，以主要黄酮成分芹菜素-7-O-b-D-葡萄糖苷为对照品作TLC检测，并草拟出该药材的质量标准草案。 第四章报道了西藏产雪莲花挥发油的化学成分分析。采用传统水蒸气蒸馏法分别从八种雪莲花全草中提取挥发油，利用气相色谱-质谱联用技术分别从水母雪莲花、绵头雪莲花、槲叶雪莲花、云状雪兔子、拉萨雪兔子、小果雪兔子、雪兔子和三指雪莲花中分别鉴定出83、83、56、34、21、20、24和20个化学成分，分别占其挥发油总量的70.7%、76.0%、82.2%、55.4%、49.7%、70.4 %、76.2%和 76.7%。 第五章为综述，总结和概括了雪莲花的化学和药理研究进展。 The dissertation reports the investigation of the chemical constituents of the genus Saussurea. Quite a lot of species in this genus are traditional Tibetan medicinal plants, and hence have been widely used in traditional Tibetan medicine. This dissertation consisted of five chapters. The first chapter is on the chemical constituents of three Saussurea plants. The second section is about the analysis of chemical constituents of Saussurea plants using HPLC-MS and ESI-MS/MS. In the third chapter, we proposed quality-control standards for the Genus Saussurea based on TLC (thin layer chromatography) and HPLC. The fourth chapter is about chemical compositions of the essential oil from the whole plant of Saussurea plants. The last chapter reviews the research progress of the Genus Saussurea. The first chapter consists of three parts. The first part is about chemical constituents of ethanol extracts from whole plant of Saussurea laniceps Hand.-Mazz. Fifteen compounds were isolated by column chromatography on normal phase silica gel and Sephadex LH-20. Among them, eleven compounds were isolated from this plant for the first time, and two compounds were isolated from Genus Saussurea for the first time. The second part is about chemical constituents of ethanol extracts from whole plant of Saussurea medusa Maxim. Fifteen compounds were isolated by column chromatography on normal phase, reversed phase silica gel and Sephadex LH-20. Five of them were isolated from this plant for the first time, and there is one new flavonoid glucoside which was identified as 6″-O-crotonoyl-homoplantaginin (M-7) based on the evidence of one- and two-dimensional nuclear magnetic resonance, mass spectrometry analysis, and alkaline hydrolysis reaction. The last part is about chemical constituents of ethanol extracts from whole plant of Saussurea tridactyla Sch.-Bip. ex Hook. f.. Seven compounds were isolated by column chromatography on normal phase silica gel and Sephadex LH-20. There is one compound which was isolated from this plant for the first time. The second chapter consists of three parts. In the first part, we analyzed the chemical constituents of S. tridactyla collected from seven different places in Tibet using HPLC-DAD-ESI-MSn. Fourteen peaks in the HPLC were identified by comparison of UV and MS spectra with those of authentic compounds, among which eight common peaks were quantified. In the second part, we analyzed the chemical constituents of eight Saussurea species using HPLC-DAD-ESI-MSn method. Fifteen peaks in the HPLC were identified by comparison of UV and MS spectra with those of authentic compounds and eight main peaks of them were quantified. In the last part, we analyzed the chemical compounds of the above eight Saussurea plants directly by ESI-MS/MS. Thirteen major compounds, including 10 flavonoids and 3 coumarins were easily rapidly identified. The third chapter consists of three parts. In the first part, we proposed a comparative high quality-control standard for S. laniceps, based on quality detection by TLC and quantity analysis by HPLC using two major compounds (umbelliferone and scopoletin) as standard compounds. In the second part, in viewing S. laniceps, S. tridactyla and S. gossypiphora as the members of one family of medicinal herbs, we suggested a quality-control standard based on the TLC detection of the two major compounds (umbelliferone and scopoletin). In the last part, we proposed a quality-control standard for S. medusa based on the TLC detection of its major component (apigenin 7-O-glucoside). The four chapter analyzed the chemical constituents of essential oil of eight Saussurea species. The essential oils were extracted from the whole plants of these samples with water stream distillation. By GC-MS analysis, we identified eighty-three compounds from S. medusa, eighty-three from S. laniceps, fifty-six from S. quercifolia, thirty-four from S. aster, twenty-one from S. kingii, twenty from S. simpsoniana, twenty-four from S. gossypiphora, and twenty from S. tridactyla respetively, which accounted for 70.7%, 76.0%, 82.2%, 55.4%, 49.7%, 70.4 %, 76.2% and 76.7% of the total essential oil, respectively. The last chapter reviews the research progress of the Genus Saussurea.