Total cobalt determination in human blood and synovial fluid using inductively coupled plasma-mass spectrometry: method validation and evaluation of performance variables affecting metal hip implant patient samples

Inductively coupled plasma with mass spectrometric detection (ICP-MS) has been used for clinical analysis of cobalt (Co) due to its sensitivity and specificity; however, media-specific validation studies are lacking. This study provides data on performance variables affecting differences between selected analytical platforms (Perkin Elmer and Agilent), tissue sample preparation, storage, and interferences affecting measurements in whole blood, serum, and synovial fluid. The limits of detection (LOD) range from 0.2–0.5 µg/L in serum and synovial fluid, and 0.6–1.7 µg Co/L in whole blood. The Agilent platform with collision reaction cell is more sensitive, while the Perkin Elmer platform with dynamic reaction cell demonstrates more polyatomic interferences near the LOD for serum and whole blood. Split sample analysis showed good accuracy, precision, and reproducibility between serum Co measurements using acid digestion or detergent dilution preparations for persons with metal hip implants or following supplement intake. The results demonstrated reliability of the ICP-MS methodology across the two analytical platforms and between two commercial laboratories for Co concentrations above 5 µg Co/L, but digestion procedures and polyatomic interferences may affect measurements in some media at lower concentrations. These studies validate the described ICP-MS methodology for clinical purposes with precautions at low cobalt concentrations (<5 µg Co/L).     

Identification and assay of microbial fatty acids during co-composting of active sewage sludge with palm waste by TMAH-thermochemolysis coupled with GC-MS

The fatty acids of two composts of active sludge with palm tree waste were investigated by thermochemolysis coupled to gas chromatography-mass spectrometry. This method (tetramethylammonium hydroxide-pyrolysis-gas chromatography-mass spectrometry) allowed the direct determination of total fatty acids (analysed as fatty acid methyl esters: FAMEs) present in the organic matter of the samples without any separation procedures. Mixture A was 1/3 sludge+2/3 palm waste and mixture B was 1/2 sludge+1/2 palm waste. The level of FAMEs rose by 8.4–33.3% and 10.8–13.4% in mixtures A and B, respectively, after 6 months of co-composting. Branched FAMEs of bacterial origin (iC15:0) rose during the thermophilic phase, in mixture A the aC17:0/aC15:0 ratio increased during the co-composting process, also in mixture B the aC16:0/C16:0 ratio rose but only during the thermophilic phase. All the FAMEs identified showed a drop at the end of co-composting except for C18:0 and C16:0. The stabilisation phase was characterised by a significant rise in the length of the aliphatic chains; the carbon preference index thus increased at the end of the composting process, indicating that the final product was proportionally richer in fatty acids of plant origin.     

循环经济学:学科特征与趋势展望

在比较分析有关循环经济学研究内容相关论述的基础上．从“自然-人类社会-空间”三维系统的角度，提出循环经济学的内涵．认为循环经济学是以缓解资源、环境、生态问题为目标，运用经济学方法研究物质流、能源流的运行机理、方式、技术、效率、机制的一门应用经济学科．并且从人地关系系统分解角度．分别界定了生态经济学、资源经济学、环境经济学与循环经济学的研究范畴．认为循环经济学是以人类系统与自然系统的相互关系及其所引起的人与人之间的相互关系为研究对象的．而生态经济学、资源经济学、环境经济学所涉及的只是人地关系中的子系统。据此，还进一步分析了当前我国循环经济学研究的主要方向、发展趋势。研究视角主要包括技术流程分析、深层生态分析和模式分析；今后的研究趋势则主要在于寻求理论创新、加强对循环经济模式的经济学分析，加强对于区域循环经济发展的长期分析、加强对于循环经济运行的多角度分析和加强循环经济学与相关学科的对比与借鉴研究。在此基础上构建包括理论体系、内容体系和方法体系在内的循环经济学研究的内容体系：     

人口结构、社会保障与机构投资者的发展——以发达国家为例

近年来我国的经济发展中出现了居民的存款储蓄不断增长与企业资金短缺、股票市场低迷并存的现象。发达国家的经验表明,社会保障制度与金融发展具有明显的相关性：社会保障制度的改革与发展。改变了居民以存款为主体的金融资产结构。使居民金融资产的选择从直接持有转向通过养老金、保险金和共同基金等机构投资者的间接持有，促进了机构投资者的迅猛发展；而机构投资者的资产越来越多的投向了证券资产。进而促进了资本市场的进一步发展。     

USING A CHOICE MODELLING APPROACH FOR CUSTOMER SERVICE STANDARDS IN URBAN WATER1

ABSTRACT: A series of reforms in the water industry in Australia has created a demand from the industry and regulators for objective methodologies to evaluate incremental changes in the customer service standards. In this paper, the use of choice modeling for estimating implicit prices associated with urban water supply attributes is explored. Results from multinomial logit (MNL) and random parameters logit (RPL) models show that increases in annual water bills and the frequency of future interruptions were the most important attributes. Implicit price confidence intervals based on the best models suggest that people are willing to pay positive amounts to achieve a water supply that is less frequently interrupted. The provision of alternative water supplies during an interruption and notification of the interruption were found to be unimportant to respondents. Choice modeling proved to be a useful technique and provided the industry and regulators with additional information for standard setting.     

Economic aspects of global change impacts and response strategies in the coastal zone of The Netherlands

Economic aspects of possible land use strategies and protection measures in coastal zones as a response to global environmental change are examined. First, some key elements are mentioned that are of critical importance for water and land management in coastal zones. Next, various socio-economic repercussions are discussed. In this context, research needs will be addressed. Subsequently, these issues are considered for the case of The Netherlands. It is concluded that integrated modelling and analysis is just starting and needs to receive more attention in order to study long run economic costs, benefits and changes in coastal zones.     

稀缺资源的转换与经济学边界的拓展

自然资源、人力资源和人造资源是支撑经济系统的三大资源．随着世界人口的增加和人类经济活动范围的不断扩大。三类资源的相对稀缺程度逐渐发生了变化。从自然资源丰富、人造资源稀缺转变为人造资源相对丰富而自然资源相对甚至绝对稀缺的状态。这种转变对经济学研究的影响就是曾经作为经济系统外生变量的人口、自然资源逐步纳入经济分析框架成为经济系统的内生变量。经济学的边界随之拓展。     

New Institutional Mechanism in China Facilitating the Global Sustainability——Environment to Be Counted in Officials'''' Performance Rating

Having argued the importance of China's sustainable development in global sustainability, the authors review the achievements of China in sustainable development, especially its institutional construction. Environment to be counted in official's political performance rating system is thought of as a new institutional mechanism in China facilitating its sustainable development and then global sustainability. Then its significance is narrated and visions in future are envisioned. In the end, certain concrete suggestions for the rating system are given in a practical way.     

重读稳态经济:循环经济热的冷思考

稳态经济观从物质与能量平衡的角度出发，主张在自然和社会经济两系统中均保持低流通率以实现可持续发展；由于稳态经济观潜在的反消费主义与反技术万能倾向。它一直没有成为主流理论．在发展循环经济的过程中，有必要反思并从稳态经济理论中汲取营养。对于自然资源和环境资源并不富裕的中国．在发展循环经济的过程中，不仅要算物质的回收利用账。更要算能量账和低熵物质的成本账。     

人口,资源与环境协调发展的综合模式研究（Ⅱ）：资源配置新论

本文在文献[3]的基础上,提出了广义资源配置的目标就是兼顾经济增长与持续发展。为了使经济理论内核中包括持续发展问题,认为系统经济学应以资源空间、商品空间和价格空间作为出发点,进而提出了系统经济学的理论框架,在此基础上运用非线性理讨论了资源配置的模式问题。