冈村凹顶藻中的倍半萜和C15-多聚乙酰类成分研究

凹顶藻属(Laurencia)海藻在分类学上属于红藻门(Rhodophyta)、红藻纲(Rhodophyceae)、仙菜目(Ceramiales)、松节藻科(Rhodomalaceae)，主要分布于热带、亚热带和温带海域的低潮线附近及深海部分，约135种，中国有20种以上。凹顶藻次级代谢产物的结构类型主要包括倍半萜、二萜、三萜/聚醚和C15-多聚乙酰等，冈村凹顶藻中，倍半萜和C15-多聚乙酰最为常见，且以卤代著称。本文对凹顶藻卤代机制的研究进行了总结，并对最近10年来从凹顶藻中分离到的倍半萜、C15-多聚乙酰类成分及其合成研究进行了综述，同时对采自山东和广东的两种冈村凹顶藻(Laurencia okamurai Yamada)的化学成分进行了比较研究，发现生长在不同地理位置的同种凹顶藻化学成分有很大差异。 干燥并粉碎的冈村凹顶藻(L. okamurai)分别进行有机溶剂提取，粗提物通过硅胶柱层析、凝胶Sephadex LH-20柱层析、反相硅胶柱层析、制备薄层层析等方法分离纯化得单体化合物，利用超导核磁共振、质谱和红外光谱等现代波谱技术鉴定化合物的结构。从上述采自不同地点的冈村凹顶藻中分离鉴定的化合物共计30个，包括新化合物8个，依次是laurenokamurenes A-E (LA1-LA5)，laurenokamurin (LA6)，laurenokaldehyde (LA7)和isochlorolaurenol (LB1)，新天然产物1个 (LA12)和已知化合物21个。其中，采自山东的冈村凹顶藻次级代谢产物结构类型相对复杂多样，从中分离到的化合物包括bisabolane型倍半萜4个，chamigrane型倍半萜5个，laurane型倍半萜6个，C15-多聚乙酰类化合物5个，其他类型化合物1个（见第III页）；从采自广东的冈村凹顶藻中分离鉴定的化合物主要为7个laurane型倍半萜和2个其他类型的化合物（见第IV页）。 对分离鉴定的部分单体化合物进行了抗细菌（金黄色葡萄球菌）活性筛选，结果表明所有的测试样品都不具有抗金黄色葡萄球菌活性。

青海湟水流域植物区系研究

湟水流域位于青海省的东部，约处于北纬35°56′－37°38′，东径100°35′－103°05′。属于青藏高原和黄土高原的过滤地带，海拔1650－4394m，全区面积约16600km^2，属于大陆性气候和高原大陆性气候类型。本区共有野生种子植物83科、400属、1234种。分别占本区所属的青藏高原植物亚区唐古特地区总科数的92．22％、总属数的78．74％、总种数的54．00％。研究表明，湟水流域植物区系特征为：（1）在唐古特地区中种类相对较丰富；（2）温带成分占2．80％，以绝对优势确定了本区系为明显的温带性质（属于以北温带成分，特别是欧亚大陆温、寒地带典型成分为优势的，兼具温性，寒温和高寒类型的温带区系性南，或可称为在温带区第中的过渡区系所具有的“复合型”区系特征）；（3）木本类型少，大多数种类为多年生草本植物，缺乏古老和原始类群，一些中国特有种衍生于其广布的亲缘种中，表明本区系具有年轻和衍生的性质；（4）我国西南高山区系和华北区系对该区系具有双重影响；（5）为青藏高原植物亚区唐古特植物地区同华北植物地区相互过渡的代表区系之一；（6）特有属和特有种少。在中国种子植物区系分区中，本区属于青藏高原植物亚区中的唐古特地区。

多机器人系统研究

本文综述了多机器人系统研究的现状,介绍了我们开展的研究工作,提出了下一步的工作设想.

基于三维物体姿态测定的全方位观察

根据遥控作业环境中物体的三维模型,可利用机器人单幅图象中物体的三条边与模型中的三条对应边,求出三维物体姿态,但解不唯一,通过将这些可能姿态所产生的图象与实际图象匹配,可求出唯一正确姿态。利用姿态测定结果,可以描绘出从任意视点观测的同时包括被操作物体与机器人在内的三维图形(虚拟图象),从而辅助遥控操作手进行作业。文中给出了在基于PC机的图象处理系统及SGI图形工作站上进行的实验结果。

测距定位技术；移动式机器人自动定位的一种新方法

建模、定位和道路规划是移动式机器人导航系统的基本问题，本论文给出了关于这三个问题，特别是定位问题的综述和参考文献，并且提出了测距定位这一新想法，即选取环境中某一点为原点，建立笛卡尔坐标参考系，把机器人移动载体视为一个质点，质点在参考系中的坐标即机器人的绝对位置，环境中物体的位置由物体边缘在参考系中的点集来描述，通过在参考系中做简单的几何计算，得知机器人对于环境内任一物体或空间点的相对位置。这一想法已初步在实验室中得以实现。定位的过程，是计算机控制激光－像机测距装置，进行对环境墙壁平面的启发式搜索和搜索成功后的测距过程，其中墙壁平面的特征和启发式规则人为地抽取，并编写在软件过程之中。实验表明，测距定位不但想法上突破了匹配定位，打算记定位等故有的定位模式，而且比较来看，其性能也是令人满意的，是一个值得注意的定位技术。

贵阳市小型燃煤锅炉烟气中汞的形态及释放

选择贵阳市某厂的1 台安装有湿法脱硫除尘的燃煤锅炉,研究湿法脱硫除尘前后燃煤烟气中颗粒态汞(Hgp ) 、氧化态汞(Hg2 + ) 、原子态汞(Hg0) 以及总汞(Hgt) 的含量和形态分布。结果显示,湿法脱硫除尘后的颗粒态汞、氧化态汞、原子态汞分别约占总汞的1014 % ,610 % ,8316 %。湿法脱硫除尘器对氧化态汞与颗粒态汞有很好的去除效率(分别为8719 % ,7611 %) ,而对原子态汞的去除效率较差(为3014 %) 。由于对该锅炉的年燃煤量统计有一定的误差以及烟气采样分析方法本身存在的误差,该锅炉输出的总汞略大于输入的总汞,质量平衡结果为: 输出P输入= 10316 %～10714 %。煤经过燃烧后,总汞的释放因子为:4117 %残留在底灰中,6517 %进入烟气中,其中经过湿法脱硫除尘器的净化,2617 %的汞随除尘废水排放到水环境中,718 %存在于经过除尘后的渣中,25105 %随清洁烟气释放到大气中。

Boundary triplets and M-functions for non-selfadjoint operators, with applications to elliptic PDEs and block operator matrices

B.M. Brown, M. Marletta, S. Naboko, I. Wood: Boundary triplets and M-functions for non-selfadjoint operators, with applications to elliptic PDEs and block operator matrices, J. London Math. Soc., June 2008; 77: 700-718. The full text of this article will be made available in this repository in June 2009 Sponsorship: EPSRC,INTAS

Intention and Causation in Medical Non-Killing: The impact of criminal law concepts on euthanasia and assisted suicide

null RAE2008

Missions : their rise and development / by Louise Creighton.

http://www.archive.org/details/missionstheirris003069mbp

The effect of variability in the powder/liquid ratio on the strength of zinc phosphate cement

Aim: To investigate (a) variability in powder/liquid proportioning (b) effect of the extremes of any such variability on diametral tensile strength (DTS), in a commercial zinc phosphate cement. Statistical analyses (a = 0.05) were by Student's t-test in the case of powder/liquid ratio and one-way ANOVA and Tukey HSD for for pair-wise comparisons of mean DTS. The Null hypotheses were that (a) the powder-liquid mixing ratios observed would not differ from the manufacturer's recommended ratio (b) DTS of the set cement samples using the extreme powder/liquid ratios observed would not differ from those made using the manufacturer's recommended ratio. Methodology: Thirty-four undergraduate dental students dispensed the components according to the manufacturer's instructions. The maximum and minimum powder/liquid ratios (m/m), together with the manufacturer's recommended ratio (m/m), were used to prepare cylindrical samples (n = 3 x 34) for DTS testing. Results: Powder/liquid ratios ranged from 2.386 to 1.018.The mean ratio (1.644 (341) m/m) was not significantly different from the manufacturer's recommended value of 1.718 (p=0.189). DTS values for the maximum and minimum ratios (m/m), respectively, were both significantly different from each other (p<0.001) and from the mean value obtained from the manufacturer's recommended ratio (m/m) (p<0.001). Conclusions: Variability exists in powder/liquid ratio (m/m) for hand dispensed zinc phosphate cement. This variability can affect the DTS of the set material.

Prospective surveillance for invasive fungal infections in hematopoietic stem cell transplant recipients, 2001-2006: overview of the Transplant-Associated Infection Surveillance Network (TRANSNET) Database.

BACKGROUND: The incidence and epidemiology of invasive fungal infections (IFIs), a leading cause of death among hematopoeitic stem cell transplant (HSCT) recipients, are derived mainly from single-institution retrospective studies. METHODS: The Transplant Associated Infections Surveillance Network, a network of 23 US transplant centers, prospectively enrolled HSCT recipients with proven and probable IFIs occurring between March 2001 and March 2006. We collected denominator data on all HSCTs preformed at each site and clinical, diagnostic, and outcome information for each IFI case. To estimate trends in IFI, we calculated the 12-month cumulative incidence among 9 sequential subcohorts. RESULTS: We identified 983 IFIs among 875 HSCT recipients. The median age of the patients was 49 years; 60% were male. Invasive aspergillosis (43%), invasive candidiasis (28%), and zygomycosis (8%) were the most common IFIs. Fifty-nine percent and 61% of IFIs were recognized within 60 days of neutropenia and graft-versus-host disease, respectively. Median onset of candidiasis and aspergillosis after HSCT was 61 days and 99 days, respectively. Within a cohort of 16,200 HSCT recipients who received their first transplants between March 2001 and September 2005 and were followed up through March 2006, we identified 718 IFIs in 639 persons. Twelve-month cumulative incidences, based on the first IFI, were 7.7 cases per 100 transplants for matched unrelated allogeneic, 8.1 cases per 100 transplants for mismatched-related allogeneic, 5.8 cases per 100 transplants for matched-related allogeneic, and 1.2 cases per 100 transplants for autologous HSCT. CONCLUSIONS: In this national prospective surveillance study of IFIs in HSCT recipients, the cumulative incidence was highest for aspergillosis, followed by candidiasis. Understanding the epidemiologic trends and burden of IFIs may lead to improved management strategies and study design.

Safer by design: simulating fire and escape at sea

When designing a new passenger ship or modifying an existing design, how do we ensure that the proposed design and crew emergency procedures are safe from an evacuation resulting from fire or other incident? In the wake of major maritime disasters such as the Scandinavian Star, Herald of Free Enterprise, Estonia and in light of the growth in the numbers of high density, high-speed ferries and large capacity cruise ships, issues concerning the evacuation of passengers and crew at sea are receiving renewed interest. Fire and evacuation models with features such as the ability to realistically simulate the spread of fire and fire suppression systems and the human response to fire as well as the capability to model human performance in heeled orientations linked to a virtual reality environment that produces realistic visualisations of the modelled scenarios are now available and can be used to aid the engineer in assessing ship design and procedures. This paper describes the maritimeEXODUS ship evacuation and the SMARTFIRE fire simulation model and provides an example application demonstrating the use of the models in performing fire and evacuation analysis for a large passenger ship partially based on the requirements of MSC circular 1033. The fire simulations include the action of a water mist system.

Multiscale modelling of dendrite growth during vacuum arc remelting

Vacuum Arc Remelting (VAR) is the accepted method for producing homogeneous, fine microstructures that are free of inclusions required for rotating grade applications. However, as ingot sizes are increasing INCONEL 718 becomes increasingly susceptible to defects such as freckles, tree rings, and white spots increases for large diameter billets. Therefore, predictive models of these defects are required to allow optimization of process parameters. In this paper, a multiscale and multi-physics model is presented to predict the development of microstructures in the VAR ingot during solidification. At the microscale, a combined stochastic nucleation approach and finite difference solution of the solute diffusion is applied in the semi-solid zone of the VAR ingot. The micromodel is coupled with a solution of the macroscale heat transfer, fluid flow and electromagnetism in the VAR process through the temperature, pressure and fluid flow fields. The main objective of this study is to achieve a better understanding of the formation of the defects in VAR by quantifying the influence of VAR processing parameters on grain nucleation and dendrite growth. In particular, the effect of different ingot growth velocities on the microstructure formation was investigated. It was found that reducing the velocity produces significantly more coarse grains.