土壤中难降解有机污染物锁定机理研究进展

有机污染物进入土壤后,随着与土壤接触时间的延长,被锁定在土壤中,生物可利用性下降.锁定可能导致过高估计难降解有机污染物的暴露风险,影响修复技术的实施.锁定发生的内在机制主要源于粘土矿物、有机质及非水相液体的不可逆吸附和微孔束缚,而影响土壤难降解有机污染物锁定的关键因素包括土壤物理化学性质和环境条件(湿度、温度、pH等).基于此,进一步阐明了目前土壤中难降解有机污染物锁定机理研究需要解决的问题,并对未来的发展趋势进行了展望.

Investigation of Degradation Behavior of Polymer on Surface of Film Due to the Existence of Monochromatic X-ray

Degradation and its temperature dependence of poly(methyl methacrylate) (PMMA) in the blend film of PMMA/SAN were investigated via ire-situ X-ray photoelectron spectroscopy(XPS). The results show that thermal degradation of PMMA takes place at 185, 130, 80 degrees C and even room temperature due to the existence of monochromatic X-ray. Furthermore, the degradation rate depends crucially on the experiment temperature.

PMo12-doped carbon ceramic composite electrode based on sol-gel chemistry and its electrocatalytic reduction of bromate

A conductive carbon ceramic composite electrode (CCE) comprised of cc-type 1:12 phosphomolybdic acid (PMo12) and carbon powder in an organically modified silicate matrix was fabricated using a sol-gel method and characterized by scanning electron microscopy, cyclic voltammetry, and Osteryoung square-wave voltammetry. Osteryoung square-wave voltammograms of the modified electrode immersed in different acidic aqueous solutions present the dependence of current and redox potential on pH. The PMo12-doped CCE shows more reversible reaction kinetics, good stability and reproducibility, especially the renewal repeatability by simple polishing in the event of surface fouling or dopant leaching. Moreover, the modified electrode shows good catalytic activity for the electrochemical reduction of bromate.

INVESTIGATION OF C-PHYCOCYANIN FROM BLUE-GREEN-ALGA SPIRULINA-PLATENSIS WITH SCANNING TUNNELING MICROSCOPE

C-phycocyanin (C-PC) was isolated from blue-green alga spirulina platensis. A scanning tunneling microscope (STM) has been used to investigate its three-dimensional structure. The samples were dialyzed before the STM experiment, and then deposited on highly oriented pyrolytic graphite (HOPG). The measurement was carried out in ambient condition at room temperature. STM images showed that C-phycocyanin was uniformly distributed on solid-state substrate HOPG. The shape of C-phycocyanin is disklike with a channel in the center. It is concluded that STM has great potential to observe the structure of biliproteins and phycobilisomes.

高温高压和不同氧逸度控制下单晶橄榄石电导率的实验研究

在1．0—4．0GPa，1123—1473K和控制氧逸度（Ni＋NiO，Fe＋Fe3O4，Fe＋FeO和Mo＋MoO2等4种氧缓冲剂）的条件下，借助YJ-3000t紧装式六面顶高温高压设备和Sarhron-1260阻抗／增益-相位分析仪，就位测定了橄榄石的电导率．实验结果表明：（1）在测定的频率范围（10^3-10^6Hz），样品的电导率对频率具有很强的依赖性；（2）随着温度（T）升高，电导率（σ）增大，lgσ与1／T之间符合Arrhenius关系；（3）在Fe＋Fe3O4氧缓冲条件下，随着压力升高，电导率降低，而活化焓和指前因子增大，并给出样品的活化能和活化体积分别为（1．25±0．08）eV和（0．105±0．025）cm^3·mol；（4）在给定的压力和温度下，随着氧逸度增加，电导率增大，活化焓降低；（5）小极化子导电机制可为橄榄石在高温高压下的导电行为提供合理的解释.

不同前处理方法对红色风化壳粒度测试结果的影响

对红色风化壳粒度分析的前处理方法，目前存在着很大差异，这在一定程度上影响了分析结果的可靠性。采用不同前处理方法对中国西南岩溶区红色风化壳样品进行了粒度测试，结果表明各方法对粒度数据有明显影响。对于富含三水铝石的样品，用盐酸溶液煮沸处理后，可以使游离铝氧化物的胶结作用解体，从而使颗粒充分分散，即方法B效果较好；而对于蒙脱石含量较高的红色风化壳，由于盐酸溶液处理后会破坏蒙脱石晶格及硅胶体的出溶，从而会对矿物产生胶结作用，用方法A较为适宜；其他粘土矿物对不同前处理方法没有明显的敏感性。当利用粘粒含量作为红色风化壳发育程度及红壤类型划分的指标时，不同前处理方法将影响到对成果的正确解释，因此选择合适的前处理方法是必需的。在碳酸盐岩上覆红色风化壳的成因研究方面，以粒度频率分布曲线作为指标时，前处理方法的不同不影响对物源指示的判读，但利用粘粒含量及粉砂／粘粒比等参数时，可能会对研究结果产生影响。

Identifying vibrations that destabilize crystals and characterize the glassy state

Greaves, George; Meneau, F.; Majerus, O.; Jones, D.G., (2005) 'Identifying vibrations that destabilize crystals and characterize the glassy state', Science 308(5726) pp.1299-1302 RAE2008

Antropoloxía e literatura oral

A proposta realizada neste traballo fai de altovolante dalgunhas reflexións que creo fundamentais para seguir camiño na investigación da literatura oral. A miña perspectiva é a da antropoloxía sociocultural, pero afecta nun sentido máis amplo ao conxunto das disciplinas sociais e humanísticas que abordan o tema da literatura oral e da oralidade en xeral. É evidente que a literatura aporta datos sobre a organización social, o estilo de vida e a Cultura dunha sociedade no pasado e no presente (1). En particular a literatura oral, é dicir, a que se transmite oralmente aínda que ás veces a encontremos escrita, é un vector privilexiado para captar os imaxinarios colectivos do grupo humano que a crea, os seus valores, as súas moralidades e crenzas. The paper presents some lines of thought considered to be fundamental in the study of oral literature. The perspective followed is one marked by socio/cultural anthropology, but one that is also related to all of those Social Sciences and Humanities that analyse oral traditions. Literature gives us data on social organization, on the life style and culture of a social group, both past and present. Oral literature, in particular, is a extremely suitable vehicle for reaching the collective imaginary of the group that creates it. (1) Fribourg, J.(1995): "Literatura oral y antropología", en Lisón Tolosana, C. (comp.): Antropología y Literatura. Zaragoza: Gobierno de Aragón, p. 37.

On the Size Distribution of Autonomous Systems

This paper explores reasons for the high degree of variability in the sizes of ASes that have recently been observed, and the processes by which this variable distribution develops. AS size distribution is important for a number of reasons. First, when modeling network topologies, an AS size distribution assists in labeling routers with an associated AS. Second, AS size has been found to be positively correlated with the degree of the AS (number of peering links), so understanding the distribution of AS sizes has implications for AS connectivity properties. Our model accounts for AS births, growth, and mergers. We analyze two models: one incorporates only the growth of hosts and ASes, and a second extends that model to include mergers of ASes. We show analytically that, given reasonable assumptions about the nature of mergers, the resulting size distribution exhibits a power law tail with the exponent independent of the details of the merging process. We estimate parameters of the models from measurements obtained from Internet registries and from BGP tables. We then compare the models solutions to empirical AS size distribution taken from Mercator and Skitter datasets, and find that the simple growth-based model yields general agreement with empirical data. Our analysis of the model in which mergers occur in a manner independent of the size of the merging ASes suggests that more detailed analysis of merger processes is needed.

The synthesis and biological evaluation of lanostane and cholestane-type natural products

The main objective of this thesis is to outline the synthetic chemistry involved in the preparation of a range of novel lanostane and cholestane derivatives, and subsequent investigation into their biological activity in cancer cells. The biological results obtained throughout the project have driven the strategic synthesis of new compounds, in an effort to optimise the anti cancer potential of lanostane and cholestane derivatives. The first chapter begins with an overview of steroidal compounds and details a literature review of the natural sources of these moieties, as well as their biosynthesis and reported synthetic derivatives. The biological activity of interesting natural and synthetic analogues is also discussed. In addition, an insight into some currently prescribed pharmaceutical compounds, with functional groups relevant to this project, is presented. The second chapter discusses the methods employed for the synthesis of these novel lanostane and cholestane derivatives, and comprises three main sections. Firstly, various oxidation products of lanosterol are synthesised, mainly via epoxidations of the C-8,9 and C- 24,25 alkenes, and also allylic oxidations at these positions. Secondly, amine derivatives of lanosterol are formed by cleaving the lanostane side chain, thereby yielding a new cholestane nucleus, and performing several reductive aminations on the resulting key aldehyde intermediates. Various amines such as piperidine, morpholine, diethylamine and aniline are employed in the reductive amination reactions to yield novel cholestane steroids with amine side chains. Finally, starting from stigmasterol and proceeding with the same methodology of cleaving the steroidal side chain and subsequently performing reductive aminations, novel cholestane derivatives of the biologically active amines are synthesised. The cytotoxicity of these compounds against CaCo-2 and U937 cell lines is presented in terms of percentage viability of cells, IC50 value and apoptosis. The MTT assay is used to determine the percentage viability of cells, and the IC50 data is generated from the MTT results. Apoptosis is measured in terms of fold increase relative to a carrier control. In summary, the compounds formed are discussed in terms of chemical synthesis, spectroscopic interpretation and biological activity. The main reaction pathways involved in the chemistry within this project are various oxidations and reductive amination. The final chapter is a detailed account of the full experimental procedures for the compounds synthesised during this work, including characterisation using spectroscopic and analytical data.

Age-related effects on the neural correlates of autobiographical memory retrieval.

Older adults recall less episodically rich autobiographical memories (AM), however, the neural basis of this effect is not clear. Using functional MRI, we examined the effects of age during search and elaboration phases of AM retrieval. Our results suggest that the age-related attenuation in the episodic richness of AMs is associated with difficulty in the strategic retrieval processes underlying recovery of information during elaboration. First, age effects on AM activity were more pronounced during elaboration than search, with older adults showing less sustained recruitment of the hippocampus and ventrolateral prefrontal cortex (VLPFC) for less episodically rich AMs. Second, there was an age-related reduction in the modulation of top-down coupling of the VLPFC on the hippocampus for episodically rich AMs. In sum, the present study shows that changes in the sustained response and coupling of the hippocampus and prefrontal cortex (PFC) underlie age-related reductions in episodic richness of the personal past.

Nurse-led behavioral management of diabetes and hypertension in community practices: a randomized trial.

BACKGROUND: Several trials have demonstrated the efficacy of nurse telephone case management for diabetes (DM) and hypertension (HTN) in academic or vertically integrated systems. Little is known about the real-world potency of these interventions. OBJECTIVE: To assess the effectiveness of nurse behavioral management of DM and HTN in community practices among patients with both diseases. DESIGN: The study was designed as a patient-level randomized controlled trial. PARTICIPANTS: Participants included adult patients with both type 2 DM and HTN who were receiving care at one of nine community fee-for-service practices. Subjects were required to have inadequately controlled DM (hemoglobin A1c [A1c] ≥ 7.5%) but could have well-controlled HTN. INTERVENTIONS: All patients received a call from a nurse experienced in DM and HTN management once every two months over a period of two years, for a total of 12 calls. Intervention patients received tailored DM- and HTN- focused behavioral content; control patients received non-tailored, non-interactive information regarding health issues unrelated to DM and HTN (e.g., skin cancer prevention). MAIN OUTCOMES AND MEASURES: Systolic blood pressure (SBP) and A1c were co-primary outcomes, measured at 6, 12, and 24 months; 24 months was the primary time point. RESULTS: Three hundred seventy-seven subjects were enrolled; 193 were randomized to intervention, 184 to control. Subjects were 55% female and 50% white; the mean baseline A1c was 9.1% (SD = 1%) and mean SBP was 142 mmHg (SD = 20). Eighty-two percent of scheduled interviews were conducted; 69% of intervention patients and 70% of control patients reached the 24-month time point. Expressing model estimated differences as (intervention--control), at 24 months, intervention patients had similar A1c [diff = 0.1 %, 95 % CI (-0.3, 0.5), p = 0.51] and SBP [diff = -0.9 mmHg, 95% CI (-5.4, 3.5), p = 0.68] values compared to control patients. Likewise, DBP (diff = 0.4 mmHg, p = 0.76), weight (diff = 0.3 kg, p = 0.80), and physical activity levels (diff = 153 MET-min/week, p = 0.41) were similar between control and intervention patients. Results were also similar at the 6- and 12-month time points. CONCLUSIONS: In nine community fee-for-service practices, telephonic nurse case management did not lead to improvement in A1c or SBP. Gains seen in telephonic behavioral self-management interventions in optimal settings may not translate to the wider range of primary care settings.

Manufacturing of uniformly-sized silicon particles for solar cell from molten metal jet by electromagnetic pinch force

Spherical silicon solar cells are expected to serve as a technology to reduce silicon usage of photovoltaic (PV) power systems[1, 2, 3]. In order to establish the spherical silicon solar cell, a manufacturing method of uniformly sized silicon particles of 1mm in diameter is required. However, it is difficult to mass-produce the mono-sized silicon particles at low cost by existent processes now. We proposed a new method to generate liquid metal droplets uniformly by applying electromagnetic pinch force to a liquid metal jet[4]. The electromagnetic force was intermittently applied to the liquid metal jet issued from a nozzle in order to fluctuate the surface of the jet. As the fluctuation grew, the liquid jet was broken up into small droplets according to a frequency of the intermittent electromagnetic force. Firstly, a preliminary experiment was carried out. A single pulse current was applied instantaneously to a single turn coil around a molten gallium jet. It was confirmed that the jet could be split up by pinch force generated by the current. And then, electromagnetic pinch force was applied intermittently to the jet. It was found that the jet was broken up into mono-sized droplets in the case of a force frequency was equal to a critical frequency[5], which corresponds to a natural disturbance wave length of the jet. Numerical simulations of the droplet generation from the liquid jet were then carried out, which consisted of an electromagnetic analysis and a fluid flow calculation with a free surface of the jet. The simulation results were compared with the experiments and the agreement between the two was quite good.