长周期光纤光栅气敏薄膜传感器结构优化

基于三包层长周期光纤光栅模型，研究了包层表面涂覆-层溶胶-凝胶气敏薄膜的长周期光纤光栅化学传感器的灵敏度Sn与薄膜光学参量（折射��n3和厚度h3）和光纤光栅结构参量（光栅周期、折变量和光栅长度）之间的关系。采用最优化数值方法，找到了获得高灵敏度所需的最佳膜层光学参量和光栅结构参量。理论计算表明，该类型传感器对膜层折射率的测量分辨率高达10^-8。实验上制作了对乙醇气体敏感的传感器，并证实了传感器结构优化的必要性。

Tobramycin与16S rRNA A位点复合物的分子动力学模拟

采用分子动力学方法(Molecular dynamics,MD)对托普霉素(Tobramycin)与16S rRNA的A位点复合物的特异性识别机制进行了理论模拟研究,模拟时间为3.6 ns. 结果表明,A位点中波动最大的部位是两个环外碱基A1492和A1493;tobramycin的环Ⅰ和环Ⅱ是其最保守的结构单元,可能参与了Tobramycin与16S rRNA的A位点之间的特异性识别. 另外,发现一个残存时间为3.6 ns的"结构化"水分子,它桥接了Tobramycin环Ⅱ��N3与环Ⅰ的N6′之间的氢键,稳定了Tobramycin的结构;Tobramycin周围水合密度较高的位点出现在环Ⅰ和环Ⅱ附近,这也正是晶体结构中形成较多水媒介氢键及动力学模拟中结构化水分子出现的位置. 动力学模拟证实Tobramycin与16S rRNA间的结合是大量氢键及水分子相互作用的结果,这有助于设计和开发以Tobramycin为基础,具有高亲和力及特异性的16S rRNA抑制剂.

Cloning, expression and subcellular distribution of a Rana grylio virus late gene encoding ERV1 homologue

An essential for respiration and viability (ERV1) homologue, 88R, was cloned and characterized from Rana grylio virus (RGV). Database searches found its homologues in all sequenced iridoviruses, and sequence alignment revealed a highly conserved motif shared by all ERV1 family proteins: Cys-X-X-Cys. RT-PCR and western blot analysis revealed that 88R begins to transcribe and translate at 6 h postinfection (p.i.) and remains detectable at 48 h p.i. during RGV infection course. Furthermore, using drug inhibition analysis by a de novo protein synthesis inhibitor and a viral DNA replication inhibitor, RGV 88R was classified as a late (L) viral gene during the in vitro infection. 88R-EGFP fusion protein was observed in both the cytoplasm and nucleus of pEGFP-N3-88R transfected EPC cells. Although result of immunofluorescence is similar, 88R protein was not detected in viromatrix. Moreover, function of RGV 88R on virus replication were evaluated by RNAi assay. Nevertheless, effect of knockdown of RGV 88R expression on virus replication was not detected in cultured fish cell lines. Collectively, current data indicate that RGV 88R was a late gene of iridovirus encoding protein that distributed both the cytoplasm and nucleus.

Identification and characterization of a novel envelope protein in Rana grylio virus

Viral envelope proteins have been proposed to play significant roles in virus infection and assembly. In this study, an envelope protein gene, 53R, was cloned and characterized from Rana grylio virus (RGV), a member of the family Iridoviridae. Database searches found its homologues in all sequenced iricloviruses, and sequence alignment revealed several conserved structural features shared by virus capsid or envelope proteins: a myristoylation site, two predicted transmembrane domains and two invariant cysteine residues. Subsequently, RT-PCR and Western blot detection revealed that the transcripts encoding RGV 53R and the protein itself appeared late during infection of fathead minnow cells and that their appearance was blocked by viral DNA replication inhibitor, indicating that RGV 53R is a late expression gene. Moreover, immunofluorescence localization found an association of 53R with virus factories in RGV-infected cells, and this association was further confirmed by expressing a 53R-GFP fusion protein in pEGFP-N3/53R-transfected cells. Furthermore, detergent extraction and Western blot detection confirmed that RGV 53R was associated with virion membrane. Therefore, the current data suggest that RGV 53R is a novel viral envelope protein and that it may play an important role in virus assembly. This is thought to be the first report on a viral envelope protein that is conserved in all sequenced iridoviruses.

Characterization of an early gene encoding for dUTPase in Rana grylio virus

dUTPase (DUT) is a ubiquitous and important enzyme responsible for regulating levels of dUTP. Here, an iridovirus DUT was identified and characterized from Rana grylio virus (RGV) which is a pathogen agent in pig frog. The DUT encodes a protein of 164aa with a predicted molecular mass of 17.4 kDa, and its transcriptional initiation site was determined by 5'RACE to start from the nucleotide A at 15 nt upstream of the initiation codon ATG. Sequence comparisons and multiple alignments suggested that RGV DUT was quite similar to other identified DUTs that function as homotrimers. Phylogenetic analysis implied that DUT horizontal transfers might have occurred between the vertebrate hosts and iridoviruses. Furthermore, its temporal expression pattern during RGV infection course was characterized by RT-PCR and Western blot analysis. It begins to transcribe and translate as early as 4 h postinfection (p.i.), and remains detectable at 48 h p.i. DUT-EGFP fusion protein was observed in the cytoplasm of pEGFP-N3-Dut transfected EPC cells. Immunofluorescence also confirmed DUT cytoplasm localization in RGV-infected cells. Using drug inhibition analysis by a de novo protein synthesis inhibitor (cycloheximide) and a viral DNA replication inhibitor (cytosine arabinofuranoside), RGV DUT was classified as an early (E) viral gene during the in vitro infection. Moreover, RGV DUT overexpression was shown that there was no effect on RGV replication by viral replication kinetics assay. (c) 2006 Published by Elsevier B.V.

Metal catalysis-free, direction-controlled planar growth of single-crystalline alpha-Si3N4 nanowires on Si(100) substrate

Single-crystalline alpha-Si3N4 nanowires are controlled to grow perpendicular to the wet-etched trenches in the SiO0.94 film on the plane of the Si substrate without metal catalysis. A detailed characterization is carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photoluminescence at 600 nm from alpha-Si3N4 nanowires is attributed to the recombination at the defect state formed by the Si dangling bond N3 equivalent to Si-center dot. The growth mechanism is considered to be related to the catalysis and nitridation of SiO nanoclusters preferably re-deposited around the inner corner of the trenches, as well as faster Si diffusion along the slanting side walls of the trenches. This simple direction-controlled growth method is compatible with the CMOS process, and could facilitate the fabrication of alpha-Si3N4 nanoelectronic or nanophotonic devices on the Si platform.

The radio counter-jet of the QSO 3C 48

We present multi- frequency radio observational results of the quasar 3C 48. The observations were carried out with the Very Large Array ( VLA) at five frequencies, 0.33, 1.5, 4.8, 8.4, and 22.5 GHz, and with the Multi- Element Radio Linked Interferometer Network ( MERLIN) at the two frequencies of 1.6 and 5 GHz. The source shows a one- sided jet to the north within 1", which then extends to the northeast and becomes diffuse. Two bright components ( N2 and N3), containing most of the flux density, are present in the northern jet. The spectral index of the two components is alpha(N2) similar to -0.99 +/- 0.12 and alpha(N3) similar to - 0.84 +/- 0.23 ( S proportional to nu(alpha)). Our images show the presence of an extended structure surrounding component N2, suggestive of strong interaction between the jet and the interstellar medium ( ISM) of the host galaxy. A steep- spectrum component, labelled S, located 0.25 " southwest to the flat- spectrum component which could be the core of 3C 48, is detected at a significance of > 15 sigma. Both the location and the steepness of the spectrum of component S suggest the presence of a counter- jet in 3C 48.

微悬臂传感器研究生物相关分子与金属离子相互作用

利用微悬臂传感器研究了生物相关分子与金属离子的相互作用过程及检测。本论文取得的主要成果如下： （1）利用微悬臂传感器在流动体系中研究了多巴胺在金表面的吸附过程及其与铁离子的相互作用与检测。结果表明，多巴胺在金表面多层吸附，通过分子间氢键和表面电荷转移效应诱导悬臂向镀金面偏转。多巴胺与铁离子的作用过程可以分为两个阶段：第一阶段，铁离子与外层多巴胺络合，并脱离悬臂表面；第二阶段，铁离子与靠近金表面层多巴胺形成化合物，并且可能先以不稳定的单齿络合，而后生成稳定的双齿螯合。利用电化学和XPS手段对上述过程进行了表征，并设计实验对推理进行了验证。多巴胺修饰的悬臂还是一个很好的铁离子传感器，具有较高的灵敏度和选择性，检测限能达到510-10 mol/L。 （2）利用微悬臂传感器在流动体系中研究了组氨酸在金表面的吸附过程及其与铁离子的相互作用与检测。考察了不同pH值和Cl-浓度对组氨酸吸附及其与铁离子作用的影响。结果表明，随着pH值的增加，组氨酸的吸附构象会发生变化，并且导致组氨酸的吸附稳定性、吸附量和分子间静电斥力增大。在碱性溶液中咪唑环较羧基基团优先在金表面发生吸附。组氨酸修饰悬臂与铁离子作用的结果表明，在中性和碱性溶液中组氨酸能与铁离子在悬臂表面形成稳定的化合物。两者的作用过程分为两个阶段：第一阶段组氨酸中咪唑环上远离金表面��N3原子与铁离子形成单齿配合物，此时化合物之间通过静电斥力使得悬臂向下偏转；第二阶段，组氨酸上靠近金表面的N1原子开始与铁离子作用，通过分子构象的改变最终与邻近的单齿配合物形成双齿配合物，并开始逐渐覆盖悬臂表面，形成网络结构使得悬臂表面形成一种收缩的应力，而使悬臂向镀金面偏转。第二阶段不但与作用时间有关，而且同氯离子的浓度紧密关联。只有当氯离子浓度大于或等于50mmol/L时，才会出现悬臂向镀金面偏转的现象。组氨酸修饰的悬臂还是一个很好的铁离子传感器，检测限能达到510-9 mol/L级。 （3）将肽（Gly-Gly-His）共价键合到MPA修饰的悬臂表面，首先研究肽与Cu2+ 的相互作用过程。研究发现作用过程与Cu2+ 的浓度有关，高浓度时Cu2+ 与肽快速吸附，并通过与不同肽链上的羧基和咪唑环配位诱导悬臂向镀金面偏转；而后肽链上的氮原子与Cu2+配位，同时构象发生变化，由直链转变成折叠状，进而增加链间的作用力使悬臂向反向偏转；而铜离子浓度低时不能实现悬臂表面快速的形成向内的拉力，所以不会产生向镀金面偏转，而直接在构象变化推动悬臂反向偏转。考察了检测过程中溶液pH、离子强度和干扰离子对检测的影响。结果表明该传感器对铜离子有较宽响应范围，最低响应浓度为210-10 mol/L。

沙地樟子松幼苗对水肥添加的生理生态响应

水分和N(氮)素是树木赖以生长和生存的必需要素，它们的有效性直接影响着树木的生长和发育，进而影响生态系统的生产力。本文研究了水分和N素添加对沙地樟子松幼苗的生理生态影响，以期确定沙地樟子松苗木生长发育的限制性因子，加深对樟子松在沙地环境中适应能力的进一步认识，为樟子松的引种栽培、苗圃水肥管理提供一定的科学依据。 本研究以樟子松幼苗为研究材料，在水泥池子（大小为1.0 m × 1.0 m）中进行。设置两组实验：（1）水、N肥（NH4NO3）添加实验，由CK（既不加水也不加N肥）、W（每10 d加水1次，水量为10.0 L•m-2）、N（10.0 g•m-2）、W+N (包含W和N 2个处理)4个处理组成，每处理3个重复，以3年生苗木为材料；（2）5个不同N肥（NH4NO3）水平（CK-0.0、N1-5.0、N2-10.0��N3-20.0和N4-25.0 g•m-2）实验，各水平3个重复，以2年生苗木为对象。通过季节性取样，测定了形态指标（株高、地径、生物量等）、生理指标（叶片相对含水量、叶片叶绿素含量、叶片脯氨酸含量等）和养分指标（植株与土壤的全N、全P浓度等）。结果如下： （1）樟子松幼苗生长与N素添加水平关系密切，3年生苗木株高、地径、单株总生物量在W、N、W+N处理下明显增加，且在W+N处理下达到最大值；在CK~N3范围内，2年生苗木的株高随N肥水平的增加明显加大，株高、地径、单株总生物量等的最大值出现��N3水平��N3水平最有利于促进樟子松幼苗的生长。 （2）相对生长速率（RGR）是衡量苗木总生物量累积状况的重要指标。RGR对水、N肥处理和N肥水平的响应不明显，随着时间的推移而下降。 （3）叶片相对含水量（RWC）在W处理、不同N肥水平处理下的变化均不明显，W+N处理使得叶片RWC明显增加；叶绿素含量在水和N肥处理下、不同N肥水平处理均未发生明显的变化，最大值分别出现在W+N处理��N3水平下。脯氨酸的含量与植物所处环境中的水分、N养分条件有一定联系，在W处理下其含量有下降趋势；在N4水平下达到最大值，起到明显的积累作用。 （4）W、N和W+N处理促使3年生苗单株全N含量明显增加，在W+N处理下达到最大值；W+N处理对单株全P含量具有明显的影响；水、N肥添加处理对3年生苗木根、茎、叶的全N浓度和全P浓度作用不明显。在N2��N3水平下，单株全N含量明显增加��N3水平促使2年生樟子松幼苗根、茎、叶中的全N含量明显升高；添加N肥对幼苗全N浓度没有产生明显的影响；��N3水平下的单株全P含量明显增加，全P浓度对N肥施加反应不明显。 （5）W+N处理明显加快了3年生苗木的净N利用效率（NNUR）和净P（磷）利用效率（NPUR），W处理和N处理对NNUR和NPUR影响不大，这说明水与N肥联合后对NNUR和NPUR产生作用，其大小关系一致，即：CK < W < N < W+N。在不同N肥水平下，2年生樟子松幼苗的NNUR和NPUR差异均不显著。NNUR和NPUR随着时间的推移而降低。 （6）根据的N∶P比值和叶片养分含量临界值以及苗木的株高、单株总生物量在不同N肥水平和水、N肥添加处理下的变化情况，可以初步判定本研究中樟子松苗木受到N养分的限制，另外，水分和N养分之间具有联合作用。因此，在苗圃育苗和造林初期，要合理地进行水肥管理。

电子与类铍N~(3+)和O~(4+)离子碰撞激发截面的相对论扭曲波计算

采用全相对论扭曲波方法,系统地计算了类��N3+和O4+离子从基态到2s2p和2p2的各激发态以及从亚稳态到2p2各激发态的电子碰撞激发截面,详细地讨论了靶态的关联效应对激发截面的影响.结果表明:对于2s-2p的单电子激发,在低能碰撞时,靶态的电子关联效应起非常重要的作用,且使得激发截面降低;而高能碰撞时,靶态波函数的描述对连续态波函数的影响比较小,对激发截面影响也比较小.对于2s2-2p2的双电子激发,其中基态2s21S0到J=0的2p23P0,1S0的激发截面较大,其主要原因是末离子态波函数与基组态波函数的混合,但是其他几个激发的激发截面较小.

污染地表水修复用微球菌的化学包埋法固定化工艺

针对污染地表水的特点,从辽河油田受石油污染的缓流河床底泥中筛选出一株能有效去除CODCr的微球菌(Micrococcussp.N3-9P),并对其进行了化学包埋法固定化.通过实验,确定了改进的聚乙烯醇-海藻酸钠共固定工艺配方(质量分数)聚乙烯醇10.5%,海藻酸钠0.5%,活性碳3%及微量生长素,优化了过程控制参数.地表水修复实验表明,96h后固定化颗粒对污染地表水中CODCr的去除率为70.9%,明显高于游离菌的33.6%.

Alternating copolymerization of carbon dioxide and propylene oxide by single-component cobalt salen complexes with various axial group

A series of single-component cobalt salen complexes, N,N'-bis(salicylidene)-1,2phenylenediamino cobaltIII X(X = Cl (1a), Br (1b), NO3 (1c), CF3COO (1d), BF4 (le), and N3 (If)) (SalphCoX), were prepared for alternating copolymerization of carbon dioxide and propylene oxide(PO) under mild condition. The axial anion X group of the SalenphCoX played important role in tailoring the catalytic activity, polymeric/cyclic carbonate selectivity, as well as stereochemistry of carbonate unit sequence in the polymer chain. SalenphCoX with an electron-withdrawing axial X group (complex 1c) was an ideal catalyst for the copolymerization of CO2 and PO to selectively produce polycarbonate with similar to 99% carbonate linkage and over 81% head-to-tail structure.

一种素食者食用的调和油及制备方法

一种素食者食用的调和油是由富含饱和脂肪酸的油脂、富含单不饱和脂肪酸的油脂、富含N6系列多不饱和脂肪酸的油脂、富��N3系列多不饱和脂肪酸的油脂在10～60℃条件下调和而成，调和油中脂肪酸的重量百分含量为饱和脂肪酸25～30wt％，单不饱和脂肪酸33～39wt％，多不饱和脂肪酸33～39wt％，其中N6系列多不饱和脂肪酸29～33wt％��N3系列多不饱和脂肪酸wt5～8％，并��N3、N6系列不饱和脂肪酸重量比例为1:4～6。本发明具有价格低廉，营养均衡，脂肪酸比例协调，适合素食者食用的优点。

Interaction of echinomycin with guanine: electrochemistry and spectroscopy studies

The interaction of antitumor antibiotic, echinomycin (Echi) with guanine (Gua) was thoroughly investigated by adsorptive transfer stripping cyclic voltammetry, ultraviolet and visible adsorption spectra (UV/Vis) and Fourier-transform infrared spectroscopy (FTIR). Electrochemistry provided a simple tool for verifying the occurrence of interaction between Echi and Gua. Echi could be accumulated from the solution and give well-defined electrochemical signals in 0.1 M phosphate buffer solution (pH 7.0) only when Gua was present on the surface of the electrochemically pretreated glass carbon electrode (GCE), suggesting a strong binding of Echi to Gua. All the acquired spectral data showed that a new adduct between Echi and Gua was formed, and two pairs of adjacent intermolecular hydrogen bonds between the Ala backbone atoms in Echi and Gua (Ala-NH to Gua-N3 and Gua-NH2 to Ala-CO) played a dominating role in the interaction. Electrochemistry coupled with spectroscopy techniques could provide a relatively easy way to obtain useful insights into the molecular mechanism of drug-DNA interactions, which should be important in the development of new anticancer drugs with specific base recognition.