Highly enhanced luminescence from single-crystalline C-60 center dot 1m-xylene nanorods

Single-crystalline C-60 center dot 1m-xylene nanorods with a hexagonal structure were successfully synthesized by evaporating a C-60 solution in m-xylene at room temperature. The ratio of the length to the diameter of the nanorods can be controlled in the range of approximate to 10 to over 1000 for different applications. The photoluminescence (PL) intensity of the nanorods is about 2 orders of magnitude higher than that for pristine C-60 crystals in air. Both UV and Raman results indicate that there is no charge transfer between C-60 and m-xylene. It was found that the interaction between C-60 and m-xylene molecules is of the van der Waals type. This interaction reduces the icosahedral symmetry of C-60 molecule and induces strong PL from the solvate nanorods.

VISCOSITY AND FLOW PROPERTIES OF CONCENTRATED-SOLUTIONS OF CHITOSAN WITH DIFFERENT DEGREES OF DEACETYLATION

The effects of the degree of deacetylation (DD) on the viscosity and flow behaviour of concentrated solutions of chitosan were investigated using 0.2 M CH3COOH and 0.2 M CH3COOH/0.1 M CH3COONa aqueous solutions as solvents. The results indicated that the

DETERMINATION OF THE MARK-HOUWINK EQUATION FOR CHITOSANS WITH DIFFERENT DEGREES OF DEACETYLATION

The values of k and alpha in the Mark-Houwink equation have been determined for chitosans with different degrees of deacetylation (DD) (69, 84, 91 and 100% respectively), in 0.2 M CH3COOH/0.1 M CH3COONa aqueous solution at 30-degrees-C by the light scattering method. It was shown that the values of alpha-decreased from 1.12 to 0.81 and the values of k increased from 0.104 x 10(-3) to 16.80 x 10(-3) ml/g, when the DD varied from 69 to 100%. This is due to a reduction of rigidity of the molecular chain and an increase of the electrostatic repulsion force of the ionic groups along the polyelectrolyte chain in chitosan solution, when the DD of chitosan increases gradually.

Identification and characterization of a myeloid differentiation factor 88 (MyD88) cDNA from Zhikong scallop Chlamys farreri

Myeloid differentiation factor 88 (MyD88) is a universal and essential adapter for the TLR/IL-1R family. In this report, the first mollusk Myd88 ortholog (named as CfMyd88) was cloned from Zhikong scallop (Chlamys farreri). The full-length cDNA of CfMyd88 was of 1554 bp, including a 5 '-terminal untranslated region (UTR) of 427 bp, a polyA tail, and an open reading frame (ORF) of 1104 bp encoding a polypeptide of 367 amino acids containing the typical TLR and IL-1R-related (TIR) domain and death domain (DD). Homology analysis revealed that the predicted amino acid sequence of CfMyd88 was homologous to a variety of previously identified Myd88s with more than 30% identity. The temporal expressions of CfMyd88 mRNA in the mixed primary cultured haemocytes stimulated by lipopolysaccharide (LPS) and peptidoglycans (PGN) were measured by real-time RT-PCR system. The mRNA expression of CfMyd88 decreased after stimulation with both LPS and PGN, and the lowest level was about 1/3 times (at 6 h) and 1/10 times (at 9 h) to that in the control group, respectively. The expression then recovered and was upregulated to two-fold at 9 h after LPS stimulation or to the original level at 12 It after PGN stimulation. The results suggest that the MyD88-dependent signaling pathway exists in scallop and was involved in the defense system. (c) 2007 Elsevier Ltd. All rights reserved.

栉孔扇贝抗鳗弧菌感染性状候选基因的多态性研究

栉孔扇贝（Chlamys farreri）是我国北方地区主要的养殖贝类之一，曾为沿海各省带来巨大的经济效益。但自1997年以来，陆续爆发的病害问题给扇贝养殖业造成了巨大的经济损失，严重影响了该产业的健康发展。目前认为培育抗病性强的扇贝优良品种是解决病害问题的根本途径。由于传统的育种方法费时费力，无法满足对良种的迫切需求，因此有必要通过分子手段加快抗病品种的培育步伐。标记辅助育种（marker assisted selection，MAS）是成功应用于动物育种中的分子手段之一，但由于缺乏与抗病性状相关的标记，MAS目前还无法在软体动物中得到应用。因此，寻找与抗病性状相关的分子标记是在软体动物中发展MAS的关键。 本研究利用鳗弧菌（Listonella anguillarum）对栉孔扇贝进行攻毒感染实验，初步得到敏感群体和抗病群体后采用PCR、PCR-RFLP、Bi-PASA PCR等方法研究了CfLysG、CfC1qDC和CfLITAF基因多态性及其与栉孔扇贝对鳗弧菌抗性的关系。 研究发现，栉孔扇贝CfLysG的基因序列中共有104个单核苷酸多态性（SNP）位点和29个插入/缺失（I/D）多态性位点。有17个多态性位点位于启动子区域，选择其中的-753 I/D、-391A/G和-284I/D多态性进行检测，发现这三个位点的基因型在敏感群体和抗病群体中的分布均符合Hardy-Weinberg平衡（P>0.05）。其中-753 ID基因型和-284 ID基因在抗病群体中的频率高于在敏感群体中的频率，但两者之间无显著性差异（P>0.05）。-391 AG基因型在抗病群体中的频率显著高于敏感群体（P=0.007），表明-391 AG基因型与栉孔扇贝对鳗弧菌的抗性显著相关。为验证这一相关性，对-391位点不同基因型的扇贝进行攻毒感染实验。统计发现，具有-391 AA基因型的扇贝累计死亡率显著高于具有-391 AG基因型的扇贝（P=0.001），进一步证实了CfLysG基因-391 AG基因型与栉孔扇贝对鳗弧菌的抗性显著相关。CfLysG基因的外显子共有3处SNP，其中仅第三外显子上的+3473 A/C为非同义突变。统计分析表明，+3473位点不同基因型在敏感群体中的分布频率符合Hardy-Weinberg平衡（P>0.05），而在抗病群体中则偏离Hardy-Weinberg平衡（P<0.01）。+3473 AA基因型在抗病群体中的频率显著高于在敏感群体中的频率（P=0.022），表明+3473 AA基因型与栉孔扇贝对鳗弧菌的抗性显著相关。CfLysG基因第1内含子存在+96 I/D和+487 I/D两处大片段的I/D多态性。统计发现，这两个位点的基因型在敏感群体和抗病群体中的分布频率均符合Hardy-Weinberg 平衡（P>0.05）。其中+96 DD基因型和+487 ID基因型在抗病群体中的频率均略高于在敏感群体中的频率，但两者之间无显著性差异（P>0.05）。表明这两个位点的多态性与栉孔扇贝对鳗弧菌的抗性无显著相关性。对CfLysG基因各多态性位点的统计分析表明，各位点之间存在不同程度的连锁不平衡，提示有单体型的存在。对19种频率>1%的单体型在敏感群体及抗病群体中的频率进行分析，发现-753 I/-391 G/-284 I/+96 I/+487 D/+3473 A单体型在抗病群体中的频率显著高于敏感群体（P=0.044），表明该单体型与栉孔扇贝对鳗弧菌的抗性显著相关。 在栉孔扇贝CfC1qDC基因cDNA序列上共发现14处SNP。对+423 T/C多态性与栉孔扇贝对鳗弧菌抗性的关系进行了分析。统计发现，+423位点各基因型在敏感群体和抗病群体中的分布均符合Hardy-Weinberg平衡（P>0.05）。+423 TT基因型在抗病群体中的频率显著高于在敏感群体中的频率（P=0.005），表明+423 TT基因型与栉孔扇贝对鳗弧菌的抗性显著相关。 在栉孔扇贝CfLITAF基因cDNA序列中共发现3处SNP及1处I/D多态性。对+145 I/D多态性进行研究，发现所有敏感个体及抗病个体中均同时存在+145 位点所有等位基因，表明+145位点多态性与栉孔扇贝对鳗弧菌的抗性不相关。 以上研究表明，栉孔扇贝CfLysG基因-391 AG基因型、+3473 AA基因型、-753 I/-391 G/-284 I/+96 I/+487 D/+3473 A单体型以及CfC1qDC基因+423 TT基因型与栉孔扇贝对鳗弧菌的抗性显著相关，提示它们可作为与栉孔扇贝抗病相关的候选分子标记应用于贝类抗病育种中，为贝类的标记辅助育种提供参考。此外，抗病相关分子标记的发现还有利于加深对扇贝发病机理的理解，并有助于发掘预防及治疗贝类疾病的新方法。

Morphological and genetic study of Prorocentrum donghaiense Lu from the East China Sea, and comparison with some related Prorocentrum species

In this paper, the detailed morphology of Prorocentrum donghaiense Lu from both field samples and cultures was examined, and a taxonomic comparison was made between P donghaiense and some related Prorocentrum spp. using morphological and molecular data and other published information. There were distinct differences among these species in morphological characteristics that historically have been presented as conservative features. The discrepancies extended beyond that of individual variations within the same species due to environmental factors. Therefore, these morphological features may not be conservative but, rather, polymorphic depending on environmental conditions. Based on this analysis, we suggest that the high-biomass bloom-forming species in the East China Sea, previously reported as Prorocentrum dentatum Stein, is P donghaiense Lu. The species reported from the East China Sea and Japanese and Korean waters appear to be the same species. Molecular data also suggest that P. dentatum (CCMP1517) and P. donghaiense are genetically identical. Therefore, the geographic distribution of P. donghaiense may be much wider than expected. (C) 2004 Elsevier B.V. All rights reserved.

Experimental evaluation of heterobeltiosis and heterosis between two populations of Pacific abalone Haliotis discus hannai Ino

A2 x 2 factorial cross between two populations of Pacific abalone Haliotis discus hannai Ino, collected separately from Dalian (D) in China and Miyagi (M) in Japan, was conducted to compare performances in fertilization rate, hatching rate, metamorphosis rate and growth at days 20, 43, 160 and 330 between purebreds (DD and MM) and crossbreds (DM and MD) and investigate the magnitude of heterobeltiosis (better parent) and heterosis (mid-parent). Heterobeltiosis and heterosis for all the traits analyzed were evidently different between crossbreds DM and MD. Heterobeltiosis in the crossbred DM varied among traits, with values of 2.5% for the fertilization rate, 2.2% for the hatching rate, -1.9% for the metamorphosis rate and 7.4% for the growth at the (lay 330. The crossbred DM displayed positive heterotic values for fertilization rate (5.4%), hatching rate (7.4%), metamorphosis rate (7.6%) and growth (12.0%) at the day 330. However, both heterobeltiosis and heterosis for all the traits in the crossbred MD were negative except those for the growth at days 20 and 43. The results indicate the importance of selecting superior hybrid varieties if the exploitation of hybrid vigor is considered in the Pacific abalone breeding program.

直接驱动机器人关节加速度反馈解耦控制

以利用线加速度传感器实际测量转动关节的加速度为基础 ,分析了机器人关节加速度反馈控制的开环模型 ,以及影响其闭环稳定性的主要因素 ;提出了闭环控制策略的设计准则 .在一台三自由度直接驱动机器人上的实验结果证明了该文分析的正确性 ,与不具备加速度反馈控制时的实验结果相比较 ,显示出这种方法的有效性