Origin of Gymnocypris przewalskii and phylogenetic history of Gymnocypris eckloni (Teleostei : Cyprinidae)

The origins and phylogenetic patterns were assessed for G. przewalskii and G. eckloni by analyzing the complete mtDNA cytochrome b gene sequence (1140bp). Phylogenetic analyses further supported that there were three mtDNA lineages (A-C) identified in G. przewalskii and G. eckloni, demonstrating that outer rakers of the first gill have little significance in the phylogeny of the Gymnocypris fishes. The network established showed that G. eckloni of the Yellow River specific haplotype A1 was a founder and it radiated all haplotypes of G. przewalskii which suggested G. przewalskii might only originate from one of two maternals of G. eckloni from the Yellow River. Fs test and mismatch analysis showed at least two expansion events in the population of G. przewalskii about 0.2734 Ma and 0.0658 Ma, while G. eckloni from Qaidam Basin could have experienced severe bottleneck effect about 0.0693 Ma. The population expansion was detected in subclades A1 and A21 with the most recent common ancestor (TMRCA) about 0.2308 +/- 0.01 Ma and 0.1319 +/- 0.015 Ma, respectively, which were within the geological age range of "Gonghe Movement" event that caused the separation of Lake Qinghai from the upper Yellow River. These results suggested the effect of the fish diversification by rapid uplift of the Qinghai-Tibetan Plateau in the Late Pleistocene.

一种单模高功率垂直腔面发射激光器及其制作方法

本发明是一种单模高功率垂直腔面发射激光器，属半导体光电子领域。其特征在于，包括P型电极(1)，P型Si衬底(2)，金属键合层(3)，P型分布布拉格反射镜(DBR)(4)，氧化限制层(5)，有源区(6)，N型DBR(7)，SiO2掩膜(8)，聚酰亚胺或苯并环丁烯(BCB)(9)，N电极(10)，光子晶体(11)，出光窗口(12)。在该结构的垂直腔面发射激光器中引入光子晶体，可增大氧化孔径，提高单模输出功率，同时采用键合技术将传统VCSEL外延片转移到Si衬底上和采用底部出光的设计，便于拉近VCSEL外延片有源区与Si衬底的距离，改善器件热学特性，进一步提高单模输出功率。

稀土氟化物固体电解质的制备、结构及电学、传感性能的研究

我们利用湿法制备了单一稀土氟化物LnF_3(Ln = La 、Ce、Nd、Gd、Tb、Dy、Er、Yb、Y), 并采用高温固相反应制备了稀土掺杂氟化物Ln_(1-x)MxF_(3-δ)(Ln = La、Ce、Gd、Yb、Y M = Ca、Sr、Ba)。用X射张衍射方法研究了它们的晶体结构。对单一稀土氟化物，LaF_3、CeF_3、NdF_3为六方晶系，GdF_3、TbF_3、DyF_3、DrF_3、YbF_3、YF_3为正交晶系。对掺杂氟化物，La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Yb_(0.70)Sr_(0.30)F_(3-δ)为固溶体，Ce_(0.95)Ca_(0.05)F_(3-δ)的晶胞参数比CeF_3的略为变小；Gd_(0.85)Ca_(0.15)F_(3-δ)、Y_(0.71)Ca_(0.29)F_(3-δ)为新化合物，Gd_(0.85)Ca_(0.15)F_(3-δ)的晶体结构由GdF_3的正交晶系变为六方晶系，其晶胞参数为：a=3.973A, C=7.124A, γ=120°, Y_(0.71)Ca_(0.29)F_(3-δ)化合物的晶体结构与YF_3相同为正交晶系，晶胞参数却较小：a=3.683A、b=6.978A, c=3.396A。 我们对氟化物的烧结陶瓷片进行了直流电导率测量。对单一稀土氟化物，结果表明六方结构的化合物的电导率高于正交结构的，对于相同结构的氟化物，一般地，稀土离子半径越大，电导率越高；对于掺杂氟化物，由于二价碱土金属离子掺杂可以提高氟离子空位浓度，因此掺杂物的电异率均高于对应的单一稀土氟化物，其中Gd_(0.85)Ca_(0.15)F_(3-δ)掺杂后变成更利于离子导电的六方结构。采用压片工艺，以La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Gd_(0.85)Ca_(0.15)F_(3-δ)和Y_(0.71)Ca_(0.29)F_(3-δ)为固体电解质材料制备电位输出式氧传感器件，并利用调节N_2、O_2流量比控制氧分压的方法，对器件的敏感性能进行测试。结果表明该类器件可在150 ℃的低温下对氧气敏感，器件的输出电位差与氧分压的对数值有较好的线性关系。器件的响应时间在2分与9分之间。该类器件的敏感机理是：氧气先吸附敏感电极上，发生还原反应后生成的氧负离子在敏感电极与固体电解质界面上发生晶格置换反应，使得氧分压的改变通过快离子即氟离子在两个界面上（另一界面为参比电极与固体电解质界面）的电化学势差的变化与输出电位差值的改变联系起来，从而实现利用输出电位差测定氧分压的目的。根据使用的敏感电极材料，可以有单电子反应和双电子反应两种敏感机理。器件是由参比电极、固体电解质、敏感电极三个部分构成。我们采用固定其中二个部分的材料，改变第三个部分的用料的方法，对器件的敏感性进行了对比研究：A、我们首先固定固体电解质为Ce_(0.95)Ca_(0.05)F_(3-δ)、敏感电极材料为Pt黑，采用不同的参比电极材料Bi+BiF_3、Sb+SbF_3、Mg+MgF_2、Zn+ZnF_2制备了器件。性能测试结果表明使用Bi+BiF_3参比电极材料的器件稳定性和敏感性都比其它器件好。器件的输出电位差取决于参比电极氟化物的标准生成自由能的大小。B、固定Bi+BiF_3为参比电极材料，Ce_(0.95)Ca_(0.05)F_(3-δ)为固体电解质，使用不同的敏感电极材料Pt黑、Pd粉、Ag粉和RuO_2制备器件。性能测试结果表明：Pt材料器件的精确度较高，Pd材料器件的响应最快（2分），RuO_2材料器件的敏感性较好。使用Ag、RuO_2敏感电极材料的器件采用的是单电子反应敏感机理：O_2 + e <-> O_2~-, O_2~- + V_F + F_(F-bar)~- <-> O_(F-bar) + O_F + F_(F-bar)。而使用Pt、Pd敏感电极材料的器件采用双电子反应敏感机理：O_2 + 2e <-> 2O~-, 2O~- + F_(F-bar) <->O_(F-bar) + F~-。C、我们固定Bi+BiF_3为参比电极材料，Pt和RuO_2为敏感电极材料，使用La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Gd_(0.85)(Ca_(0.015)F_(3-δ)、Yb_(0.70)Ca_(0.29)F_(3-δ)制备了两个系列的器件。结果表明，无论是使用Pt还是使用RuO_2为敏感电极材料，都有下列的结论：用Ce_(0.95)Ca_(0.05)F_(3-δ)的器件的精确度较高，La_(0.95)Ba_(0.05)F_(3-δ)材料器件的敏感性最好，而Gd_(0.85)(Ca_(0.015)F_(3-δ的响应最快（Pt器件2分，RuO_2器件5分）。并未发现同时具备各种较好性能的器件，与敏感电极材料对器件性能的影响相比，固体电解质材料的影响要小。对于材料完全相同的器件，我们还对工艺条件影响作了初步研究。制备器件的工艺条件由于各种难以控制的因素不会每次、每批完全相同，工艺条件的差别也会影响器件的各方面性能。研究结果表明，工艺差别对器件的输出电位差值和响应时间的影响较大，对敏感性能的影响则较小。

基于Vif-APOBEC3G相互作用的抗HIV-1药物研究

载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(apolipoprotein B mRNA-editing enzyme catalyticpolypeptidelike3G,APOBEC3G或A3G)是人体天然抗病毒分子,可以使病毒逆转录形成的cDNA的胞嘧啶(C)脱氨为尿嘧啶(U),产生鸟嘌呤(G)→腺嘌呤(A)超突变,导致病毒转录产物突变,从而达到抑制病毒复制的作用。HIV-1的辅助蛋白Vif,可与APOBEC3G相互作用并导致其被降解,使得这一天然抗病毒机制失效,进而增强了HIV的感染力。Vif与APOBEC3G这种相互作用为抗HIV药物提供了新靶点。针对Vif-APOBEC3G相互作用的抗HIV抑制剂已经成为研究热点。本文综述了Vif和APOBEC3G的结构、二者的相互作用,以及基于这一相互作用的抗HIV-1抑制剂研究进展。

CO2和O3浓度升高对农作物次生代谢和残茬分解的影响

近几年来,近地面CO2、O3浓度快速升高已经对农作物生长发育造成了很大的影响，引起国内外学者的广泛关注。本文以C3作物春小麦辽春17为试材，利用农田开顶式气室（OTCs)研究CO2和O3浓度增加及其交互作用对春小麦不同发育时期生物量、总酚量、黄酮含量及成熟期产量性状的影响，以及对土壤酶活性及土壤中酚酸类物质含量的影响，同时监测了残茬分解过程中C、N的变化，还比较了小麦（C3）和玉米（C4）次生代谢的响应差异，为研究农作物对全球变化的响应与反馈提供了科学依据。结果表明： 1. CO2浓度升高条件下，春小麦生物量和产量性状都显著高于对照； O3浓度升高条件下，显著低于对照；CO2和O3交互作用下各项指标处于二者之间。 2. CO2、O3浓度升高及其交互作用显著增加了春小麦叶片中的总酚含量；其中CO2浓度升高对C3作物的影响比对C4作物大。 在小麦生长前期，各处理总黄酮含量均低于对照；而到成熟期，各处理下黄酮含量都显著高于对照。其中小麦体内PAL酶活性和C/N与酚类化合物含量变化趋势一致。 3. CO2、O3浓度升高对小麦生长初期土壤过氧化氢酶、蔗糖酶和多酚氧化酶活性影响不明显，到成熟期O3浓度增加，3种酶活性均显著地高于对照；其中土壤中多酚氧化酶活性升高，和土壤中酚类化合物的积累有关，经相关分析（r=0.625，n=23，p=0.015)，二者存在显著相关关系。 4. 在CO2、O3作用下两种残茬混合物（土和根、土和秸秆) C/N在分解初期急剧下降，随后呈现平缓的下降趋势，但各处理间无显著性差异，说明短期的CO2、O3浓度升高，虽然影响了植物的化学成分组成，但对分解速率影响较小。

V-F变换在激光物理实验中的新型应用

介绍了一套十分适合应用于准连续激光物理实验的变换装置。该套装置不但可以将热电偶激光功率计输出的直流型模拟电压量变换成计数脉冲输出,还可以对光离子引起的、探测器给出的脉冲型模拟电压量进行累计变换。经过详细的模拟测试得知它变换激光功率的积分线性≤±0.015%,变换光离子脉冲信号的积分线性≤±0.23%。以上测试结果表明该套变换装置已经满足了一般激光物理实验的精度要求。

Study of urinary 8-hydroxydeoxyguanosine as a biomarker of oxidative DNA damage in diabetic nephropathy patients

Increased oxidative stress induced by hyperglycemia may contribute to the pathogenesis of diabetic complications. Urinary 8-hydroxydeoxyguanosine (8-OHdG) has been reported to serve as a sensitive biomarker of oxidative DNA damage and also of oxidative stress. This article studied oxidative DNA damage in patients with diabetic nephropathy and in healthy control subjects by urinary 8-OHdG evaluations. Contents of 8-OHdG in urine were analyzed by capillary electrophoresis with end-column amperometric detection (CE-AD) after a single-step solid-phase extraction (SPE). Levels of urinary 8-OHdG in diabetic nephropathy patients with macroalbuminuria was significant higher than in control subjects (5.72 +/- 6.89 mumol/mol creatinine versus 2.33 +/- 2.83 mumol/mol creatinine, P = 0.018). A significant difference of 24 h urinary 8-OHdG excretions exists between the patients with macroalbuminuria and the patients with nonnoalbuminuria (19.2 +/- 16.8 mug/24 h versus 8.1 +/- 1.7 mug/24 h, P = 0.015). There was a positive correlation between urinary excretion of 8-OHdG and glycosylated hemoglobin (HbA(1)c) (r = 0.287, P = 0.022). A weak correlation exists between the levels of 8-OHdG and triglyceride (r = 0.230, P = 0.074). However, the urinary 8-OHdG contents are not correlated with blood pressure and total cholesterol. The increased excretion of urinary 8-OHdG is seen as indicating an increased systemic level of oxidative DNA damage in diabetic nephropathy patients. (C) 2004 Elsevier B.V. All rights reserved.

潮棕壤不同利用方式下植物线虫垂直分布研究(英文)

2003 年11 月,在中国科学院沈阳生态实验站潮棕壤经过不同利用方式后对水稻田、玉米地、撂荒地和林地开展了植物线虫垂直分布(0–15 cm 各土层)特征研究。研究结果表明:不同土地利用方式下的某些优势属线虫随着土壤深度增加而呈下降趋势。螺旋属(Helicotylenchus)线虫是4 种土地利用方式中最优势的属。水田丝尾属(Filenchus)、平滑属(Psilenchus)和垫刃属(Tylenchus)线虫主要分布在上层(0–20 cm),而撂荒地、林地中的针属(Paratylenchus)线虫及玉米地中的短体属(Pratylenchus)线虫能够分布在更深的土层(0–80 cm)。本研究揭示,植物线虫优势属数量与土壤化学特性指标存在显著相关关系。不同利用方式螺旋属线虫数量与土壤C/N 比、全碳、全氮、全磷、碱解氮及Olsen-P含量呈显著正相关;水田丝尾属和平滑属线虫、玉米地短体属线虫、撂荒地针属线虫与土壤pH 程显著负相关,与土壤全碳、全氮及碱解氮呈显著正相关。为了更正确地评价植物线虫种群数量,有必要根据植物线虫优势属的垂直分布特征来确定取样深度。图1 表1 参21。

土壤有机质对土霉素在土壤中吸附-解吸的影响

采用批量平衡方法,研究了土霉素在原土及去除有机质土壤中的吸附和解吸.结果表明,土霉素在原土和去除有机质土壤中的吸附和解吸等温线均不同程度地偏离线性模型,其中Freundlich模型可以对吸附和解吸数据进行良好的非线性拟合,在不同土壤以及不同土壤处理中的拟合相关系数(r)均达到极显著水平.去除有机质能够降低土霉素在土壤中的吸附容量(lgKf),但增加了吸附强度(1/n).土霉素在土壤上的解吸过程存在明显的滞后现象,在所设土霉素浓度范围内,土霉素在褐土和红壤中的平均滞后系数(HIa)分别为0.039和0.015;去除有机质后的褐土和红壤对土霉素的解吸滞后现象显著增强(P<0.01),其HIa分别增加到0.068和0.028.

Synthesis, photophysical properties, and theoretical studies on pyrrole-containing bromo Re(I) complex

Two bromo rhenium(I) carbonyl complexes with the formula of [Re(CO)(3)(L)Br], where L = 1,10-phenanthroline (Phen-Re) and 5-(1H-pyrrol-1-yl)-1,10-phenanthroline (Pyph-Re), were successfully synthesized with the aim to analyze the effect of the pyrrole (Py) moiety on the photophysical properties of Pyph-Re. It was found that the triplet metal-to-ligand charge-transfer d pi (Re) --> pi*(N-N) emission of Phen-Re and Pyph-Re centered at ca. 527 nm with the luminescence quantum yield (LQY) of 0.015 and ca. 578 nm with the LQY of 0.011, respectively. At the same time, the geometrical structures of the ground state and the absorption spectral properties of Phen-Re and Pyph-Re were also calculated with the 6-31G* basis set employed on C, H, N, O, and Br atoms, and LANL2DZ adopted on Re atom.

Chiral separation of promethazine by capillary electrophoresis with end-column amperometric detection

Sensitive end-column amperometric detection has been successfully coupled to capillary electrophoresis for chiral separation of promethazine, with a carbon fiber microdisk electrode as working electrode. Baseline separation and sensitive detection were achieved under optimum conditions: 0.030 M Na2HPO4 and 0.015 M citric acid at pH = 2.50, 1.0 mM beta -CD, 10 kV separation voltage, and detection potential 1.10 V (vs Ag/AgCl). The numbers of theoretical plates were higher than 700000, and the detection limit was 5 x 10(-8) M. On-line treatment of the electrode has also been studied and discussed.

Separation of promethazine and thioridazine using capillary electrophoresis with end-column amperometric detection

Promethazine and thioridazine were separated and detected by capillary electrophoresis with end-column amperometric detection. The influence of pH Value on oxidation potential, the peak current and the resolution were studied and the following conditions was selected: 0.03 M Na2HPO4 and 0.015 M citric acid at pH 3.0, detection potential at 1.10 V. The detection limits of these two substances were in the range of 10(-8) mol/l. The linear range spanned two to three orders of magnitude. This method was applied to the detection of promethazine and thioridazine spiked in urine. (C) 1999 Elsevier Science B.V. All rights reserved.

Laser light-scattering study of novel thermoplastics .1. Phenolphthalein poly(aryl ether ketone)

Five different molecular weight phenolphthalein poly(aryl ether ketone) (PEK-C) fractions in CHCl3 were studied by static and dynamic laser light scattering(LLS). The dynamic LLS revealed that the PEK-C samples contain some large polymer clusters. These large clusters can be removed by filtering the solution with a 0.1-mu m filter. We found that the persistence length of PEK-C in CHCl3 at 25 degrees C is similar to 2 nm and the Flory characteristic ratio, C-infinity is similar to 25. Our results showed that [R(g)(2)](1/2)(z) = (3.50+/-0.20) x 10(-2)M(w)(0.54+/-0.01) and [D] = (2.37+/-0.05) x 10(-4)M(w)(-0.55+/-0.01), with [R(g)(2)](1/2)(z), M(w), and [D] being the z-average radius of gyration, the weight-average molecular weight, and the z-average translational diffusion coefficient, respectively. A combination of static and dynamic LLS results enabled us to determine D = (2.20+/-0.10) x 10(-4)M(-0.555+/-0.015), where D and M correspond to monodisperse species. Using this calibration between D and M,we have determined molecular weight distributions of five PEK-C fractions from their corresponding translational diffusion coefficient distribution.

A DYNAMIC LASER LIGHT-SCATTERING STUDY OF CHITOSAN IN AQUEOUS-SOLUTION

The solution behavior of four chitosans (91% deacetylated chitin) with different molecular weights in 0.2M CH3COOH/0.1M CH3COONa aqueous solution was investigated at 25 degrees C by dynamic laser light scattering (LLS). The Laplace inversion of the precisely measured intensity-intensity time correlation function leads us to an estimate of the line-width distribution G(Gamma), which could be further reduced to a translational diffusion coefficient distribution G(D). By using a combination of static and dynamic LLS results, i.e. Mw and G(D), we were able to establish a calibration of D = k(D)M(-alpha D) with k(D) = (3.14 +/- 0.20) X 10(-4) and alpha(D) = 0.655 +/- 0.015. By using this calibration, we successfully converted G(D) into a molecular weight distribution f(w)(M). The larger alpha(D) value confirms that the chitosan chain is slightly extended in aqueous solution even in the presence of salts. This is mainly due to its backbone and polyelectrolytes nature. As a very sensitive technique, our dynamic LLS results also revealed that even in dilute solution chitosan still forms a small amount of larger sized aggregates that have ben overlooked in previous studies. The calibration obtained in this study will provide another way to characterize the molecular weight distribution of chitosan in aqueous solution at room temperature. (C) 1995 John Wiley & Sons, Inc.