循环经济的定量化评价方法研究

循环经济的推行需要建立一套衡量物质在经济系统中循环程度的指标体系。本文根据经济系统内部物质流动的基本特征。建立了封闭和开放的经济系统的物质流总量模型。基于这两个模型构建了评价循环经济的指标：循环指数I1和循环指数I2。最后，运用这两个指标分别对日本1987年和2000年的物质流动状况进行了评价。并对评价结果进行了分析。     

大肠杆菌植酸酶在毕赤酵母中的表达与纯化

为探讨植酸酶的结构与功能,研究了来源于大肠杆菌的植酸酶基因在酵母中的表达和纯化条件.将含有大肠杆菌植酸酶基因的毕赤酵母工程菌在不同甲醇浓度和不同诱导时间下培养,检测植酸酶的表达情况.结果表明:诱导培养基中一次性添加2.5%的甲醇,诱导96 h后,蛋白浓度达到1.36 mg mL-1,酶活力达到6 530 U mL-1;将在毕赤酵母中表达的植酸酶粗酶液经过硫酸铵盐析、Resource S柱和Superdex-75三步纯化,得到单峰纯的蛋白,比活力为137 280 Umg-1.用圆二色谱分析纯化后的蛋白在pH 5.0和8.0环境中的结构变化,结果显示pH 8.0环境使大肠杆菌植酸酶发生了变性.图3参16     

Effects of lead and selected pyrethroids/piperonyl butoxide alone and in combination on Na,K‐ATPase

In vitro effects of Pb²⁺, the pyrethroid insecticides cypermethrin, fenvalerate and the syner‐gist piperonyl butoxide on sodium‐potassium‐activated adenosine triphosphatase (Na,K‐ATPase) from dog kidney were determined. Pb²⁺ with an estimated IC50 value of 5.2 μM was found to be a potent inhibitor of Na,K‐ATPase activity, whereas Na,K‐ATPase was less sensitive to the pyrethroids tested and piperonyl butoxide. Investigation with circular dichroism (CD) spec‐troscopy showed that inhibition occurs through conformational changes of the α‐subunit of the enzyme. The kinetic characteristics of inhibition of Na,K‐ATPase with varying substrate (ATP) concentrations as well as with varying Na⁺ concentrations exhibited a competitive type of inhibition with Pb²⁺ in the μM range. With Pb²⁺ alone in the enzyme assay no conformational changes of the protein could be observed which confirmed the assumption that Pb²⁺ can bind to the Na⁺ binding site of the α‐subunit. Uncompetitive type of inhibition occurred with varied K⁺ concentrations demonstrating that this cation binding site is not affected directly by Pb²⁺.

Complete reversal of Pb²⁺ by DTT confirms that a possible target for interaction of this heavy metal ion with Na, K‐ATPase are specific SH groups.

Synergistic effects could only be determined with higher Pb²⁺ concentrations of 3, 5 and 7 μM plus piperonyl butoxide while all other combinations with this heavy metal plus organic substances where of the additive type. With CD spectroscopy also only additive effects were observed. These results demonstrate that higher concentrations of piperonyl butoxide favor the binding of Pb²⁺ to the Na⁺ binding site by conformational changes of the protein.     

The Essence of a Recycling Economy: Circular Utilization of Resources

Abstract

By analyzing the relationship between a recycling economy and sustainable development theory, this article puts forward the basic concept of a recycling economy as a dynamic economic operational model, and explains the four basic characteristics. It is stressed that the essential element of a recycling economy is the use of resources circularly. In the end, this article analyzes the phenomena of utilizing the recycling economy concept incorrectly, and sets forth a number of problems that should be noted during the process of developing a recycling economy in China.     

欧盟资源节约型循环经济发展对我国的启示

近年来,欧盟的循环经济逐步向资源节约型发展转变,而不再仅仅局限于废物的循环利用。通过对欧盟资源节约型循环经济的历史沿革进行梳理,介绍了该运动发起以来欧盟典型成员国中循环经济发展的新动向。在此基础上从资源节约利用的法律规制、环境审计制度及加快技术创新步伐三个角度,为我国循环经济的转型提供发展思路和完善措施。     

发展循环经济建设节约型社会——蓬莱市的实践与思考

发展循环经济、创建节约型社会,是贯彻落实科学发展观的必然要求,体现了以人为本、可持续发展的理念,是我国全面建设小康社会的战略选择,符合当今世界的发展潮流。山东蓬莱市在发展循环经济、建设节约型社会中进行了很好的实践,通过调查和解析蓬莱市发展循环经济的策略和实践经验,将会给我们新的启迪。     

电力工业循环经济发展模式及主要措施探讨

介绍了我国电力工业的发展现状，归纳总结了存在的问题。论述了电力工业发展循环经济的必要性，提出了电力工业发展循环经济的模式和主要措施。     

我国再生资源循环经济的策略研究

在今天全球经济快速发展的同时，环境污染、资源浪费等问题已日益引起人们的关注。提高绿色环保意识，在可持续发展的战略下开发可再生资源，发展循环经济，是促进人与自然和谐的必然选择。我国加入WTO后，再生资源业面临着一系列机遇和挑战，因此，应积极学习和借鉴发达国家的先进理念和先进经验，在推进社会经济发展的同时，通过制度创新和科技进步，积极发展再生资源循环经济。     

旅游区循环经济生态系统的构建

对旅游区循环经济生态系统的概念进行解释,分析了其组成与特征.并运用模型化的研究方法探讨各系统构成规律,旅游区循环经济生态系统由内生子系统、外生子系统、共生子系统组成,具有开放性、循环性、层次性、本土性、自我调节性等基本特征。     

发展有色金属工业循环经济初探

分析了湖南省郴州市有色金属工业发展存在的问题,指出循环经济是有色金属工业实现可持续发展的必然选择,并从完善法律、政策体系,引进先进技术,建立生态工业园等方面探讨有色金属工业如何发展循环经济,从而实现经济、资源、环境的协调发展。