2,3,7,8-TCDD对稀有鮈鲫幼体超微结构影响的观察

国家自然科学基金29607004

Effects of 2,3,7,8-TCDD and benzo[a]pyrene on modulating vitellogenin expression in primary culture of crucian carp (Carassius auratus) hepatocytes

Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestrogen screening model was established by measuring Vtg induction in cultured primary hepatocytes from crucian carp. Vtg production was detected by biotin-avidin sandwich ELISA method while Vtg and cytochrome P4501A1 (CYP1A1) mRNA induction were measured by semi- quantitative PCR-primer dropping technique. Vtg and Vtg mRNA were dose-dependently induced by diethylstilbestrol (DES, 0.2-200 ng/mL) in hepatocytes of crucian carp. Co-treatment of the DES-induced hepatocytes with either 2,3,7,8-TCDD (TCDD, 0.1-4 pg/mL) or benzo[a]pyrene (B[a]P, 5-1000 ng/mL) resulted in a reduction of Vtg production and an increment of CYP1A1 mRNA expression both in a dose dependent manner, indicating the anti-estrogenic effects of the compounds. However, at lower tested concentrations, TCDD (0.1, 0.2 pg/mL), B[a]P (5 ng/mL) seemed to have a potentiating effect on Vtg expression and secretion, although by their own these compounds had no observable estrogenic effect on Vtg induction. Tamoxifen (a selective estrogen receptor modulators, 1 nmol/L-1 mumol/L), and P-naphtho-flavone (beta-NF, an aryl hydrocarbon receptor inducing compounds, 2.5-1000 ng/mL) also were employed to study the possible interactions in DES-induced Vtg expression. In co-treatment of the DES-induced hepatocytes with beta-NF or tamoxifen, the decrease in Vtg production did parallel induction of CYP1A1 for beta-NF, but tamoxifen inhibited Vtg induction did not parallel induced CYP1A1 expression in all test concentrations. On the contrary, it was found that in co-treatment of the TCDD-induced hepatocytes with DES, TCDD induced CYP1A1 mRNA production was inhibited by DES also. These results implicated a possible cross talk between estrogen receptor- and aryl hydrocarbon receptor-mediated pathways in the hepatocytes.

Long-term toxic impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the reproduction, sexual differentiation, and development of different life stages of Gobiocypris rarus and Daphnia magna

The sexual ratio of Gobiocypris rarus exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 17 beta -estradiol from embryo to sexually mature revealed feminization and overdevelopment of connective tissue in male fish gonad in 2-30 pg/L TCDD concentration range. Daphnia magna was not sensitive to the high dose of TCDD (0.1-1000 ng/ml), but the reproduction of D. magna treated with TCDD decreased after the 8th day. 7-Ethoxyresorufin-O-deethylase (EROD) activities in newly fertilized eggs of G. rarus exposed to TCDD dosage groups (1000-100,000 pg/L) were significantly induced and increased with TCDD concentrations at the early life stage, while no difference was found between low TCDD dosage groups (<100 pg/L), but a good relationship between the EROD activity and the TCDD concentration was observed during a long-term developmental stage. There was a pericardial edema formed in a 2-week yolk-sac at the concentration of 1000 pg/L TCDD. But in the exposure group (2 pg/L TCDD for 120 days), the cell nuclei of hepatocytes was far from the center and packed toward the cell membrane; the cristae of most mitochondria in the cell dropped and collapsed; the rough endoplasmic reticulum broke into fragments; and numerous lipid droplets formed in the cell. (C) 2001 Academic Press.

ф2”和 ф3”非掺Si-GaAs单晶（片）研究

于G批量导入至Hzhangdi

2,3'-联吡啶还原合成毒藜碱、安那他品和异毒藜碱

本论文从2，3'-联吡啶出发，利用两个吡啶环上氮的反应活性差异，选择性合成了单烷基盐1-甲基-2，3，-联吡啶盐、1-甲基-1，一氧-2，3，-联吡啶盐和1'-甲基／节基2，3气联吡啶盐，还原单烷基盐合成了天然生物碱毒黎碱、安那他品和异毒黎碱及其衍生物：对异毒黎碱的合成由还原N，-节基盐后脱节基简化为一步实现还原和脱节基直接得到异毒黎碱。通过用（R）-BINOL和（S）-BINOL对N，-节基异毒黎碱拆分得到了旋光纯的N，-节基异毒黎碱和异毒黎碱，-N，-节基异毒黎碱的旋光度［a］D20：-61．50（c＝2．0，乙醇），卜异毒黎碱的旋光度fa］D20：-14．4"（c-1．0，乙醇）；将C关异毒黎碱用（RMTPA和（s）MT队衍生为Mosher酞胺，应用Mosllel方法确定了C）异毒黎碱手性中心的绝对构型为R型，即（R）-C）异毒黎碱，同时发现，由（R）一MTPA合成的Mosller酞胺中顺式旋转异构体占优。而通常在环胺的Mosller酞胺中，是反式旋转异构体占优。这一例外被MollteCarlo模型模拟计算结果解释：稀溶液中C卜异毒黎碱的Moshel－酞胺，顺式构型能量上比反式更有利。不对称合成天然生物碱更具有挑战性。对异毒黎碱还原合成中的呱l淀烯类中间体，用BINAP-灿催化体系进行了催化不对称还原的合成研究，氢化N'-节基-1，，4，，5，，6，-四氢一2，3，一联吡陡时得到了最高为21．5％的对映体选择性，而对N'-节基一1，，2'，5'，6，-四氢-2，3'一联吡陡的氢化则只得到了不超过10．0％的对映体选择性。

巨磁电阻材料La_(2/3)Ca_(1/3)Mn(O_(1-x),F_x)_3的研究

主要采用了X射线衍射、Mossbauer谱、磁测量等方法系统研究了块体巨磁电阻材料La_(2/3)Ca_(1/3)Mn_(1-x)Fe_xO_3在不同铁含量(0≤x≤0.84)时结构、性能、磁性的变化，并给予合理的解释。在0

陕西黄龙树轮年表的建立及其2-3月降水记录

IEECAS SKLLQG

L-shell ionization accompanied by one-electron capture in Cq+, Oq+ (q=2,3)-Ne collisions

The L-shell ionization processes of a Ne gas target associated with single-electron capture by bombardment of Cq+ and Oq+ (q=2,3) are investigated using the projectile-recoil-ion coincidence method in the energy range from 80 to 400 keV/u (v(p)=1.8-4 a.u.). The cross-section ratios (R-k1) of k-fold ionization to single capture are compared with the results for He2+-Ne collisions by Dubois [Phys. Rev. A 36, 2585 (1987)]. All the velocity dependences are quite similar. The ratios increase as the projectile energy increases in the lower-energy region, reach the maxima for projectile energies around E-max=160q(1/2) keV/u, and then decrease at higher energies. These results qualitatively agree with our calculations in terms of the Bohr-Lindhard model within the independent-electron approximation.

Defect production in silicon carbide irradiated with Ne and Xe ions with energy of 2.3 MeV/amu

In the present work specimens of mono-crystalline silicon carbide (4H polytype) were irradiated to three successively increasing ion fluences ranging from 7.2 x 10(14) to 6.0 x 10(16) ions/cm(2) (corresponding to the peak displacement damage of 1, 4 and 13 dpa) with Ne and Xe ions respectively with the energy of 2.3 MeV/amu. The irradiated specimens were subsequently annealed at temperatures of 1173 and 1273 K. Defect structure was investigated with transmission electron microscopy (TEM) using a cross-sectional specimen preparation technique. The typical microstructures of the annealed specimens irradiated with Ne or Xe ions to high fluences are characterized by small gas bubbles in high concentration in the peak damage region and black dots and dislocation loops (located in the basal plane) in a shallower and broader depth region. Larger dislocation loops were observed in the Xe-ion irradiated specimen than in the Ne-ion irradiated specimen at the same peak damage level. The enhanced formation of dislocation loops in the case of Xe-ion irradiation is understandable by assuming stronger inclination of heavier inert-gas atoms to occupy substitute site in the peak damage region.

钯/铁双金属对土壤中2,2′,3,4,4′,5,5′-七氯联苯的催化脱氯研究

采用Fe0还原、钯催化法对土壤中2,2′,3,4,4′,5,5′-七氯联苯的的还原特性进行了实验研究.结果表明,Pd/Fe双金属能有效地进行2,2′,3,4,4′,5,5′-七氯联苯的催化脱氯.在钯化率为0.05%、钯/铁加入量1 g、初始pH为5.6、反应时间5 d的条件下,钯/铁双金属对土壤中2,2′,3,4,4′,5,5′-七氯联苯去除率达54%.实验还考察了钯化率、初始pH、反应时间、钯/铁投加量、2,2′,3,4,4′,5,5′-七氯联苯初始浓度等参数对2,2′,3,4,4′,5,5′-七氯联苯脱氯效果的影响.研究表明,较高的钯化率、钯/铁加入量,较低的2,2′,3,4,4′,5,5′-七氯联苯初始浓度及弱酸性等条件更有利于Pd/Fe对2,2′,3,4,4′,5,5′-七氯联苯的还原脱氯.在Pd/Fe双金属表面,2,2′,3,4,4′,5,5′-七氯联苯的脱氯符合一级动力学反应,反应速率常数为0.014 2/h,其半衰期为49 h.利用实验数据,对钯/铁双金属作用下的2,2′,3,4,4′,5,5′-七氯联苯还原脱氯的反应机制也进行了分析.