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1.
张其春  郗永勤 《生态学报》2017,37(11):3607-3618
挖掘城市废弃物中有价值的资源,已经成为世界各国开展废弃物开发与管理的共同选择。产业共生是推动经济绿色发展和提高资源效率的战略工具,已经成为探讨废弃物资源化利用问题的重要视角。将产业共生理论引入城市废弃物资源化利用领域,提出城市废弃物资源化共生网络的概念,并将其典型特征概括为"四个统一",即价值网络与责任网络的统一,集聚共生与虚拟共生的统一,稳健型与脆弱性的统一以及自组织性与主体建构性的统一。借鉴超网络理论构建城市废弃物资源化共生网络体系的结构模型,并从共生单元、共生模式、共生界面和共生环境4个层面对该模型进行详细解析。城市废弃物资源化共生网络可分为核心网络和外围网络,两者之间存在全方位、多层次的合作机制。在城市废弃物资源化共生网络中,共生单元具有多层次性和多样性特征,它们之间存在着不同类型、效率各异的共生关系,推动共生模式向对称互惠一体化共生进化是破解城市废弃物资源化利用难题的关键;共生界面具有物质交换、能量传递、信息共享、知识传播及利益协调等多样化功能,而共生关系的进化以及共生界面功能发挥又依赖于优越的共生环境。此外,城市废弃物资源化共生网络有依托型、平等型、嵌套型和虚拟型等4种运作模式,国内典型案例分析表明这4种运作模式将长期并存。  相似文献   

2.
本试验的目的在于检测广西巴马小型猪骨骼肌中mi R-423-5p基因的表达情况及构建p LV-mi R-423-5p慢病毒载体并在C2C12细胞中进行验证。通过q RT-PCR方法检测背最长肌中mi R-423-5p的表达,设计特异性引物对mi R-423-5p基因的前体序列进行扩增并定向克隆到慢病毒载体p LV-CMV-mcs-3xflag-EF1-GFP(p LV)上,鉴定正确的重组质粒用脂质体转染法转染进C2C12细胞,q RT-PCR检测mi R-423-5p的表达情况。结果表明广西巴马小型猪背最长肌中mi R-423-5p的表达水平随着月龄的增长而不断上升,同时成功构建了p LV-mi R-423-5p慢病毒载体。该项研究为进一步寻找mi R-423-5p基因调控骨骼肌生长发育的机制提供理论基础,对肉质性状分子改良提供有益的线索。  相似文献   

3.
基于生态效率的江西省循环经济发展模式   总被引:3,自引:0,他引:3  
黄和平 《生态学报》2015,35(9):2894-2901
循环经济发展模式的研究是当今可持续发展研究及政府相关决策的核心内容,生态效率则是循环经济的合适测度,它是资源能源效率和环境效率的综合表征指标。基于生态效率度量模型和循环经济发展模式的判别模型,以江西省为例,分析其在2000-2010年间循环经济发展模式的变化轨迹。结果表明:(1) 能源消耗与经济发展表现出同步增长的趋势;(2) 各种资源和环境效率均有所上升,其环境效率总体上大于资源效率,按效率增加快慢的排序为:固体废弃物排放效率 > 建设用地效率 > COD排放效率 > 水资源效率 > SO2排放效率 > 能源效率;(3) 江西省循环经济发展走的是一条由传统线性经济模式到末端治理模式再到循环经济模式的发展道路,符合环境库兹尼茨曲线发展规律,即无害化→减量化→资源化。对研究方法的创新性进行了谨慎的探讨,对区域循环经济发展所应注意的问题提出的建议。  相似文献   

4.
基于能值分析法的矿区循环经济系统生态效率分析   总被引:2,自引:0,他引:2  
孙玉峰  郭全营 《生态学报》2014,34(3):710-717
从系统的角度界定了循环经济和矿区循环经济的内涵,提出了煤炭矿区循环经济系统的基本框架,并以能值分析法为基础构建了矿区循环经济系统生态效率评价指标体系与方法。运用所构建的评价指标体系与方法对山东某矿区进行了研究,得出该矿区循环经济系统2007—2011年5年间的能值效率变化趋势图和生态效率指数趋势图,研究结果与该矿区的实际发展趋势基本一致。表明运用能值分析法所建立的评价指标体系具有较强的有效性,并且对煤炭矿区发展循环经济、提高生态效率具有重要指导意义和参考价值。  相似文献   

5.
基于生态效率的辽宁省循环经济分析   总被引:7,自引:0,他引:7  
韩瑞玲  佟连军  宋亚楠 《生态学报》2011,31(16):4732-4740
生态效率与循环经济相辅相成。基于区域生态效率评价是考量区域循环经济的重要内容,又基于目前对于循环经济与生态效率结合的实证研究相对较少,因此,以生态效率理论为基础,对我国最早开展循环经济的试点省份——辽宁省的循环经济发展作以综合衡量。通过生态效率度量模型与循环经济度量模型,以辽宁省1990~2008年数据为基础,运用基于熵权的TOPSIS方法,分别计算了19a间辽宁省各年的资源效率、环境效率、生态效率,进而综合评价了辽宁省循环经济发展轨迹。研究表明:在19a间,辽宁省生态效率总体呈现波动上升态势,经历了传统经济发展模式——末端治理模式——循环经济模式的转变;19a间,辽宁省循环经济发展状态总体上处于循环性不断增强的状态,即经济发展的同时,环境压力不断减小。研究证明了辽宁省2002年实行循环经济以来取得了明显成效,对全国尤其是东北地区发展循环经济,走新型工业化道路具有重要的示范意义。  相似文献   

6.
目的:探讨Mi R-145在低氧诱导的心肌细胞凋亡模型中的表达及其意义。方法:在正常和低氧条件下,采用RT-qPCR检测乳大鼠原代心肌细胞mi R-145的表达,进一步采用mi R-145抑制剂和拟似物处理心肌细胞,将细胞置于37℃密闭的缺氧盒中(95%N2和5%CO_2)培养,采用Caspase-3活性分析和TUNEL检测心肌细胞凋亡情况。通过结扎SD大鼠冠状动脉左前降支(LAD)建立心肌缺血再灌注(I/R)模型,了解mi R-145在缺血再灌注损伤中的作用。结果:mi R-145过表达可抑制缺氧诱导的心肌细胞凋亡。转染mi R-145抑制剂后,细胞对缺氧更敏感。缺血0.5h、1h和3h的心肌组织中mi R-145的表达明显低于周围非缺血心肌组织。缺氧3h、6h、12h时mi R-145水平明显下调。在缺血再灌注损伤模型中,mimic组Mi R-145表达明显高于对照组,而凋亡细胞(%)和梗死面积危险区(%)明显低于对照组。结论:Mi R-145可以抑制缺氧诱导的心肌细胞凋亡,减小缺血再灌注损伤导致的心肌梗死面积。  相似文献   

7.
中国科学院昆明动物研究所刘次全研究员等 ,在中国科学院化学研究所STM实验室首次观察到变性条件下λ噬菌体DNA三链辫状结构的直观形貌 ;在此基础上 ,参照TAT三碱基体的有关结构参数 ,分别在M - 2 40 0计算机和SGI系统的4D/ 80s、 4D/ 2 0G和SGIIndigoR40 0 0上成功的构建了国内外第一个三链辫状结构模型 ;进而就三碱基体模型和能力学 ,DNA三链结构模型和能力学 ,以及三链DNA碱基配对相互作用三链和三链辫状DNA构象比较方面 ,进行了系统的定量和半定量的理论生物学研究。在取得较大进展的基础上 ,又对…  相似文献   

8.
刘传庚  王发明 《生态学报》2009,29(12):6748-6753
发展循环经济是构建和谐矿区,实现矿区可持续发展的必然选择,建立循环经济评价指标体系是评判循环经济发展质量的主要依据.依据西山公司企业循环经济发展水平评价指标体系构建的4个基本原则,构建了一套西山公司循环经济发展水平的评价指标体系,该指标体系由目标层、准则层、指标层3个等级,管理、环境、经济3个系统共25个具体指标组成,并提出了西山公司循环经济发展水平的评价模型.  相似文献   

9.
零模型是判定网络嵌套性的重要依据, 菌根共生关系网络经常出现高度非对称性, 该文通过探究矩阵非对称变化对基于不同零模型构建方法的网络嵌套性的影响, 试图为非对称网络零模型的选择提供依据。结果表明: 不同零模型保守性不同, 增加限定条件减少零模型构建过程中的自由空间, 高度限定条件易导致第II类错误。高度非对称网络会增加基于完全随机(r00)零模型的矩阵温度(NT)偏离、降低配对重叠度(NODF)偏离, 标准化指数z-score值显示网络非对称增加后有助于NTNODF显著性判定。行或列限定对非对称网络嵌套性判定的影响存在差异, 列限定(c0)的网络嵌套性判定对网络非对称性变化的响应规律与r00零模型的响应趋势基本一致, 具有更低的嵌套性偏离和标准差值。行限定(r0, 包括行列限定(backtrack))零模型NT值和NT偏移随矩阵非对称性的变化保持稳定, 较之c0零模型在高度非对称网络中呈现更低的NODF偏离值。选用完全随机和限定零模型相结合的方法, 有助于更加准确判断非对称网络是否具有嵌套结构。高度非对称网络嵌套性判定中对行属性特征比较敏感, 不同非对称性网络间嵌套性水平相比较时选用r0零模型要优于r00和c0零模型。  相似文献   

10.
为探究mi R-181b-5p靶向调控TIMP3对apo E~(-/-)鼠动脉粥样硬化炎症的影响,本研究基于生物信息学预测筛选,并采用双荧光素酶报告基因系统验证mi R-181b-5p靶基因。同时在ox-LDL刺激THP-1巨噬细胞及apo E~(-/-)动脉粥样硬化模型小鼠中检测mi R-181b-5p靶基因m RNA及蛋白水平的表达情况,并且检测转染mi R-181b-5p后细胞水平和动物体内炎症因子TNF-α、INF-γ、IL-1β、IL-18、CCL2的表达变化。此外,通过病理切片方法检测转染mi R-181b-5p后小鼠主动脉窦处病变情况。研究通过双荧光素酶报告基因系统验证TIMP3为mi R-181b-5p靶基因,并在ox-LDL刺激THP-1巨噬细胞及apo E~(-/-)动脉粥样硬化模型小鼠中证明了mi R-181b-5p可以降低TIMP3转录水平从而降低其蛋白水平表达,同时研究发现mi R-181b-5p在细胞水平和动物体内均会增强炎症因子TNF-α、INF-γ、IL-1β、IL-18、CCL2的表达,并可以增加小鼠主动脉窦处病变面积。研究认为在动脉粥样硬化发生中,mi R-181b-5p可以增加病变面积并且提升相关炎症因子的表达、分泌,其作用机理很可能是通过抑制靶基因TIMP3表达,进而降低TIMP3蛋白水平实现的,为研究动脉粥样硬化机制提供了理论依据。  相似文献   

11.
G.A.M. King 《Bio Systems》1981,13(4):225-234
The hypercycle is a chemical model for reproduction which has been advocated for early stages of biological evolution. Its advantage is thought to lie in the high rate of growth conferred by hyperbolic kinetics. Earlier work has also indicated a saturation phase at large constituent concentrations. The present paper shows that both the saturation phase and the phase of hyperbolic growth have been introduced into the kinetics by making some of the reactions reversible. Reversibility is not essential to the operation of the hypercycle and the system with irreversible reactions grows faster. However, even the fastest hypercycle does not grow as fast as the simple auto-catalyst obtained by removing that reaction which is characteristic of the hypercycle. Also, both because the hypercycle is not a coherent system and because its growth requires reactions among separated constituents in the medium, it is more subject to decay than a simple autocatalytic particle. With greater complexity, slower growth, and more severe decay, the hypercycle is not a satisfactory alternative to conventional models of reproduction.  相似文献   

12.
依据系统论的基本原理,人类疾病动物模型采用整体设计,统筹考虑模型与实验动物生物学特性方面的相似性、模型复制的重复性、可靠性、适用性、可控性、易行性和经济性等,以便模型复制的顺利开展。整体性原则应贯穿整个模型复制过程,使复制的模型具有科学性和实用性。模型复制要落实系统论的相关性原则,一个模型不是孤立的,动物的各系统、各器官、各分子之间是相互联系,人类和动物在生物学、解剖学、组织学、胚胎学、生理学、病理学等方面的相互联系,疾病的发生、发展是相互联系的,相关性原则为动物模型研究人类疾病提供了理论依据。动物模型在时间和空间上处于不断运动变化发展之中,在研究模型的过程中,要用动态的方法而不是静止的方法来研究动物模型,应根据疾病的特点,分成不同的阶段,结合动物的免疫功能、营养状况、疾病的发展、转归等采用不同的对策。模型的复制采用最优化原则,要求模型设计最优化,选用高质量的实验动物,减少动物使用数量,保护动物福利与伦理,最终实现模型评价体系的最优化。  相似文献   

13.
论生态产业链的柔性   总被引:18,自引:0,他引:18  
汪毅  陆雍森 《生态学杂志》2004,23(6):138-142
当前的全球经济模式忽视了基本的生态环境准则。人类社会为谋求进一步生存和发展的需求 ,正在促进全球经济模式由物质单向流动的线性经济向生态型循环经济的重组与转型。循环经济是一种运用生态学规律来指导人类社会的经济活动 ,循环经济在工业上的实施主要集中在生态产业链的组建上 ,是基于对自然生态系统中的物料和能量高效利用的模仿 ,以提高产业链中物料和能量的利用效率。结合对一些初见规模的产业链的实地考察和案例研究 ,着重论证了产业链的构建过程中的柔性问题 ,主要从风险的角度包括经营管理风险、维护风险和或有风险等角度探讨了产业链所承担的风险及其注意事项 ,以说明产业链的柔性对于产业链抵御外界变化的恢复能力是关键因素。  相似文献   

14.
The relation between the graphical structure and two measures of stability of a compartmental model is studied. The two are resilience as measured by deviation from equilibrium throughout the history of the system and mean first passage time from a central compartment back to itself. A number of examples are studied and a theory developed for models whose graphical structure is in the form of an advanced rosette. The resilience, known to increase with complexity, is shown to increase as well with uneveness in length of food chains. The mean first passage time, on the other hand, depends only on the number of food chains and their average length.  相似文献   

15.
The instability of the autogen   总被引:1,自引:1,他引:0  
The autogen theory has sought to provide a mechanism for the rapid origin of a self-replicating chemical system from short, random oligomers. The autogen is considered in terms of hypercycle theory, and its dynamic behavior is subjected to fixed point analysis. It is shown that the components of the autogen are incapable of stable coexistence.  相似文献   

16.
Apolipoprotein A-I (apoA-I) is the major protein associated with high density lipoprotein (HDL), and its plasma levels have been correlated with protection against atherosclerosis. Unfortunately, the structural basis of this phenomenon is not fully understood. Over 25 years of study have produced two general models of apoA-I structure in discoidal HDL complexes. The "belt" model states that the amphipathic helices of apoA-I are aligned perpendicular to the acyl chains of the lipid bilayer, whereas the "picket fence" model argues that the helices are aligned parallel with the acyl chains. To distinguish between the two models, various single tryptophan mutants of apoA-I were analyzed in reconstituted, discoidal HDL particles composed of phospholipids containing nitroxide spin labels at various positions along the acyl chain. We have previously used this technique to show that the orientation of helix 4 of apoA-I is most consistent with the belt model. In this study, we performed additional control experiments on helix 4, and we extended the results by performing the same analysis on the remaining 22-mer helices (helices 1, 2, 5, 6, 7, 8, and 10) of human apoA-I. For each helix, two different mutants were produced that each contained a probe Trp occurring two helical turns apart. In the belt model, the two Trp residues in each helix should exhibit maximal quenching at the same nitroxide group position on the lipid acyl chains. For the picket fence model, maximal quenching should occur at two different levels in the bilayer. The results show that the majority of the helices are in an orientation that is consistent with a belt model, because most Trp residues localized to a position about 5 A from the center of the bilayer. This study corroborates a belt hypothesis for the majority of the helices of apoA-I in phospholipid discs.  相似文献   

17.
The protein and solvent structure of the CTP-liganded form of aspartate carbamoyltransferase from Escherichia coli yields an R-factor of 0.155 for data to a resolution of 2.6 A. The model has 7353 protein atoms, 945 sites for solvent, and two molecules of CTP. A total of 25 of the 912 residues of the model exist in more than one conformation. The root-mean-square deviation of bond lengths and angles from their ideal values is 0.013 A and 2.1 degrees, respectively. The model reported here reflects a correction in the trace of the regulatory chain. One molecule of CTP binds to each of the two regulatory chains of the asymmetric unit of the crystal. The interactions between the pyrimidine of each CTP molecule and the protein are similar. The 4-amino group of CTP binds to the carbonyl groups of residues 89 (tyrosine) and 12 (isoleucine) of the regulatory chain. The nitrogen of position 3 of the pyrimidine binds to the amide group of residue 12; the 2-keto group binds to lysine 60. The 2'-OH group of the ribose forms hydrogen bonds with lysine 60 and the carbonyl group of residue 9 (valine). The binding of the phosphate groups of CTP to the regulatory chain probably reflects an incomplete association of CTP with the enzyme at pH 5.8. A lattice contact influences the interaction between the triphosphate group of one CTP molecule and the protein. For the other CTP molecule, only lysine 94 binds to the phosphate groups of CTP. Of the two regulatory and two catalytic chains of the asymmetric unit of the crystal, there are only two significant violations of non-crystallographic symmetry. The active site in the vicinity of arginine 54 of one catalytic chain is larger than the active site of its non-crystallographic mate. The "expanded" cavity accommodates four solvent molecules in the vicinity of arginine 54 as opposed to two molecules of water for the "contracted" cavity. Furthermore, arginine 54 in the "expanded" pocket adopts two conformations, either hydrogen-bonding to glutamate 86 or to the phenolic oxygen atom of tyrosine 98; residues 86 and 98 are in a catalytic chain related by 3-fold symmetry to the catalytic chain of arginine 54. In the "contracted" pocket, arginine 54 binds only to glutamate 86.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

18.
19.
The formation of intermediary glucans, mature starch, and phytoglycogen was studied using leaves of Arabidopsis thaliana wild type and dbe mutant, which lacks plastidic isoamylase (Zeeman, S. C., Umemoto, T., Lue, W. L., Au-Yeung, P., Martin, C., Smith, A. M., and Chen, J. (1998) Plant Cell 10, 1699-1711). A new approach to the study of starch biosynthesis was developed based on "very short pulse" labeling of leaf starch through photosynthetic fixation of (14)CO(2). This allowed selective analysis of the structure of starch formed within a 30-s period. This time frame is shorter than the period required for the formation of a single crystalline amylopectin lamella and consequently permits a direct analysis of intermediary structures during granule formation. Analysis of chain length distribution showed that the most recently formed outer layer of the granules has a structure different from the mature starch. The outer layer is enriched in short chains that are 6-11 glucose residues long. Side chains with 6 glucose residues are the shortest abundant chains formed, and they are formed exclusively by transfer from donor chains of 12 glucose residues or longer. The labeling pattern shows that chain transfer resulting in branching is a rapid and efficient process, and the preferential labeling of shorter chains in the intermediary granule bound glucan is suggested to be a direct consequence of efficient branching. Although similar, the short chain intermediary structure is not identical to phytoglycogen, which is an even more highly branched molecule with very few longer chains (more than 40 glucose residues). Pulse and chase labeling profiles for the dbe mutant showed that the final structure is more highly branched than the intermediary structures, which implies that branching of phytoglycogen occurs over a longer time period than branching of starch.  相似文献   

20.
M Shimizu 《Origins of life》1984,14(1-4):531-538
The role of "theoretical physics" in the elucidation of the origin of life has been advanced by Eigen's hypercycle theory on ancient protein synthesis system and by Dyson's random drift theory on the autocatalytic formation of enzymes, although these approaches from the informational side involve many problems to be resolved. On the other hand, our C4N model calls for a stronger role of physico-chemistry in the understanding of the origin of life. Plant virus and movable genes could be the fossil vestiges of the ancient protein synthetic system, where tRNA identical to mRNA identical to gene. It is pointed out that functional differentiation of proteins closely correlates with the structure of the primitive tRNAs. Possible initial forms of the primitive tRNAs used by the earliest organisms are explicitly shown, in which the above correlation is carefully taken into account. The system of the primitive genes and the primitive enzymes in the proto-cellular membrane, say the marigranule, might simulate the earliest organism.  相似文献   

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