河西走廊山地-绿洲-荒漠复合系统耦合的景观生态学机制

系统耦合的基础为非生物环境的空间异质性,基本条件为具有类型相同并且相互连通的廓道,系统耦合的景观生态学机制为非生物环境的空间分异和各种干扰导致的景观异质化,各种干扰是系统耦合的介质,系统耦合从本质上可以被看作尺度变大过程中景观组分的融合与性质转换的过程,系统耦合根据干扰的性质可以分为自然耦合和人为耦合2类,自然耦合是人为耦合的基础,系统生态生产力的提高取决于人为耦合的优化过程。     

部分国家和地区分级诊疗特点及启示

通过剖析部分国家和地区分级诊疗的特点,即分级诊疗是医疗卫生服务体系健全的自然结果,分级诊疗的实质在于服务整合,合理的支付制度是分级诊疗的重要促进因素;提出以强基层、建机制的原则发展分级诊疗,将医疗机构分工合作、服务功能整合作为分级诊疗的重要路径,增强医保对医疗服务体系的影响力以促进分级诊疗等建议。     

“山地-绿洲-荒漠”复合系统土地利用变化的生态系统服务权衡与协同效应——以张掖市为例

开展复合生态系统土地利用变化的生态服务效应研究可为优化国土空间格局和强化生态系统管理提供重要的基础依据。以干旱区"山地-绿洲-荒漠"复合系统的典型区域张掖市为例,基于1987年、2000年和2018年3期土地利用数据,以乡级行政区为基本单元,引入相对优势度指数划分山地、绿洲、荒漠子系统,研究复合系统的土地利用变化特征及生态系统服务权衡/协同效应。结果表明：（1）张掖市复合系统呈现地域分异特征,由南部山地系统,中部绿洲系统和北部荒漠系统构成;山地系统以林地和草地为主,绿洲系统以耕地和建设用地为主,荒漠系统以未利用地为主。（2）从时间上看,2000-2018年各系统的土地利用变化更强烈,其中,绿洲系统的耕地面积增加量最大,为363.08km²,荒漠系统的建设用地面积增加幅度最大,为78.23%。各系统土地利用转移模式为：山地系统以草地转耕地为主,绿洲系统和荒漠系统以未利用地转耕地为主。（3）张掖市复合系统的生态服务价值呈增加趋势,其中,荒漠系统生态服务价值量的增幅最大,各子系统的价值量之间的关系表现为山地系统 > 绿洲系统 > 荒漠系统,耕地对各系统生态服务价值贡献量最大。（4）张掖市土地利用变化的协同效应大于权衡效应,其中荒漠系统的生态服务之间均为协同关系,山地系统中供给服务与其他服务呈现权衡关系,占比32.73%,绿洲系统中调节服务与其他服务呈现权衡关系,占比18.18%。     

生态产业共生系统仿真研究

通过ABM方法研究生态产业共生系统,利用STARLOGO软件平台,并结合案例分析生态产业共生系统的宏观规律。研究结果表明,(1)对于规模相当的不同的生态产业共生系统,在资源输入一定情况下,直接利用输入资源的企业总规模大于对系统内废弃物再利用的企业总规模是有利于系统稳定的:(2)对于特定的生态产业共生系统,系统稳定性对系统参数改变时的敏感性是不一样的,其中对污染物产出指标最敏感,对污染物产生量与系统产出的比例关系其次,对资源输入指标最不敏感;(3)系统时间序列稳定性的变化主要由节点处企业Ⅱ的不稳定性导致。     

门诊预约服务体系建设中的问题与对策

门诊预约服务在政府的倡导下广泛开展,门诊预约服务体系的建设是现阶段的主要任务。预约体系包括信息系统、服务系统、管理系统和评价系统,各系统相互配合构成统一的整体。目前预约服务还面临着不少难题,对不同系统的主要问题和解决思路作一简要探讨。     

The blood vascular system in the head of the herring gull (Larus argentatus)

The structure and development of the blood vascular system in the head of the herring gull (Larus argentatus) have been studied using injection techniques and histological sections. Three different but interconnected divisions of the arterial system are recognized in the adult: the cerebral carotid artery system, the external ophthalmic artery system, and the external carotid artery system. Embryologically, the arterial system is characterized by changes in the relative development of these three divisions; the cerebral carotid system being the most prominent in the first half of the embryonic period. The venous system is divided into two parts, the rostral cephalic system and the caudal cephalic system, which drain separate regions of the head. The Rete ophthalmicum, which is an arteriovenous network associated with the external ophthalmic artery system, can be identified from the fifth day of incubation, and its development appears to be coupled with changes in the arterial supply to the eye. The possibility of a homology between the Rete ophthalmicum of birds and the Rete caroticum of mammals is briefly discussed.     

Escherichia coli K-12 mutants that allow transport of maltose via the beta-galactoside transport system.

We have isolated mutants of Escherichia coli that have an altered beta-galactoside transport system. This altered transport system is able to transport a sugar, maltose, that the wild-type beta-galactoside transport system is unable to transport. The mutation that alters the specificity of the transport system is in the lacY gene, and we refer to the allele as lacYmal. The lacYmal allele was detected originally in strains in which the lac genes were fused to the malF gene. Thus, as a result of gene fusion and isolation of the lacYmal mutation, a new transport system was evolved with regulatory properties and specificity similar to those of the original maltose transport system. Maltose transport via the lacYmal gene product is independent of all of the normal maltose transport system components. The altered transport system shows a higher affinity than the wild-type transport system for two normal substrates of the beta-galactoside transport system, thiomethyl-beta-D-galactoside and o-nitrophenyl-beta-D-galactoside.     

Difference in transport of leucine in attached and suspended 3T3 cells.

3T3 cells in subconfluent culture take up leucine through a transport system which has a relatively high affinity for leucine (M system). When the culture becomes confluent, the M system is turned off and leucine is transported by another system which has a low affinity for leucine (S system). The M system is reactivated by transferring the cells into subconfluent cultures. In suspension cultures 3T3 cells, initiated from confluent cultures, the M system is not activated and leucine is transported by the S system. In cells suspended from subconfluent culture, the M system continues to operate at a high level for four hours and then is gradually turned off. Tumor virus transformed 3T3 cells (SV3T3 and Py3T3) grow quite well in suspension culture and transport leucine both in monolayer and suspension through a high affinity system, with a high Vmax value. A derivative of 3T3, 3T3/41, which grows in suspension much more slowly than tumor virus transformed 3T3 cells, also takes up leucine through a high affinity transport system both in monolayer and suspension but its Vmax value is lower than that of the transformed cells.     

中国特色现代医院管理制度的基本框架与发展路径

建立现代医院管理制度是提高医院竞争力的紧迫要求,也是我国公立医院改革发展的必然趋势。从内部和外部两个方面对中国特色现代医院管理制度进行了界定,强调现代医院外部管理制度重点是医院管理体制创新,现代医院内部管理制度的核心是建立医院的法人治理结构和机制。阐述了中国特色现代医院管理制度的基本框架,并提出中国现代医院管理制度的发展路径,为构建理想的现代医院管理制度提供了思路。     

Modulation of dynamic parameters of muscle reflex by selective activation of its gamma system

The ability of the gamma system to modify the dynamics of the muscle reflex control system is investigated. The dynamics of the triceps surae muscle in decerebrate cat preparations with intact reflex loops were modulated by contralateral tibial and peroneal nerve stimulation. The parameters of the mathematical models representing the muscle reflex system were estimated by the least squares method. The behaviour of the mathematical models of the system, under various degrees of gamma system stimulation, was then studied in response to disturbance inputs. It is shown that the gamma motor system is an efficient agent for carrying out modifications in the dynamics of the muscle reflex system. The possible functional significance of this phenomenon within the framework of operation of the muscular control system is discussed with reference to optimal adaptive system concepts.     

Improving cell-free protein synthesis for stable-isotope labeling

Cell-free protein synthesis is suitable for stable-isotope labeling of proteins for NMR analysis. The Escherichia coli cell-free system containing potassium acetate for efficient translation (KOAc system) is usually used for stable-isotope labeling, although it is less productive than other systems. A system containing a high concentration of potassium l-glutamate (l-Glu system), instead of potassium acetate, is highly productive, but cannot be used for stable-isotope labeling of Glu residues. In this study, we have developed a new cell-free system that uses potassium d-glutamate (d-Glu system). The productivity of the d-Glu system is approximately twice that of the KOAc system. The cross peak intensities in the ¹H–¹⁵N HSQC spectrum of the uniformly stable-isotope labeled Ras protein, prepared with the d-Glu system, were similar to those obtained with the KOAc system, except that the Asp intensities were much higher for the protein produced with the d-Glu system. These results indicate that the d-Glu system is a highly productive cell-free system that is especially useful for stable-isotope labeling of proteins. Electronic Supplementary Material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

Anaerobic fumarate transport in Escherichia coli by an fnr-dependent dicarboxylate uptake system which is different from the aerobic dicarboxylate uptake system.

Escherichia coli grown anaerobically with fumarate as electron acceptor is able to take up C4-dicarboxylates by a specific transport system. The system differs in all tested parameters from the known aerobic C4-dicarboxylate transporter. The anaerobic transport system shows higher transport rates (95 mumol/g [dry weight] per min versus 30 mumol/g/min) and higher Kms (400 versus 30 microM) for fumarate than for the aerobic system. Mutants lacking the aerobic dicarboxylate uptake system are able to grow anaerobically at the expense of fumarate respiration and transport dicarboxylates with wild-type rates after anaerobic but not after aerobic growth. Transport by the anaerobic system is stimulated by preloading the bacteria with dicarboxylates. The anaerobic transport system catalyzes homologous and heterologous antiport of dicarboxylates, whereas the aerobic system operates only in the unidirectional mode. The anaerobic antiport is measurable only in anaerobically grown bacteria with fnr+ backgrounds. Additionally, the system is inhibited by incubation of resting bacteria with physiological electron acceptors such as O2, nitrate, dimethyl sulfoxide, and fumarate. The inhibition is reversed by the presence of reducing agents. It is suggested that the physiological role of the system is a fumarate/succinate antiport under conditions of fumarate respiration.     

用于体外人工肝支持系统的肝细胞研究

目前,人工肝支持系统正在成为急性肝衰竭患者体外有效的肝支持治疗手段,其中以生物人工肝为主附加血或血浆灌流组成的体外组合型人工肝辅助装置最为人们关注,主要包含肝酶类、肝细胞成分、肝组织片及培养肝细胞系统等,其中又以对肝细胞培养系统的研究最为广泛。本文综述了国内外有关肝细胞的来源、培养方式、所需肝细胞数量等问题的研究进展。     

Characterization of a transport system for anionic amino acids in human fibroblast lysosomes

L-Aspartate and L-glutamate are transported into human fibroblast lysosomes by a single, low Km, Na(+)-independent transport system, which has been provisionally named lysosomal system d. This system resembles the Na(+)-dependent plasma membrane system chi-AG, although these differences have been observed: (1) lysosomal system d recognizes the D- as well as the L-isomers of both aspartate and glutamate, whereas only for aspartate is the D-isomer recognized by system chi-AG; (2) the anion L-homocysteate is not accepted by system chi-AG, but is an effective inhibitor of lysosomal system d; (3) N-methyl, alpha-methyl, and omega-hydroxamate derivatives of both aspartate and glutamate inhibit lysosomal system d, but only the aspartate derivatives are accepted by system chi-AG; (4) lysosomal system d shows a preference for the substrate amino group in the alpha-position, a preference not seen for system chi-AG. These points imply differences at the two recognition sites with respect to substrate length, size, and rotation, with the lysosomal site generally being the less restrictive.     

Development of the nervous system in the acorn worm Balanoglossus simodensis: insights into nervous system evolution

SUMMARY To examine the evolutionary origin of the chordate nervous system, an outgroup comparison with hemichordates is needed. When the nervous systems of chordates and hemichordates are compared, two possibilities have been proposed, one of which is that the chordate nervous system has evolved from the nervous system of hemichordate‐like larva and the other that it is comparable to the adult nervous system of hemichordates. To address this issue, we investigated the entire developmental process of the nervous system in the acorn worm Balanoglossus simodensis. In tornaria larvae, the nervous system developed along the longitudinal ciliary band and the telotroch, but no neurons were observed in the ventral band or the perianal ciliary ring throughout the developmental stages. The adult nervous system began to develop at the dorsal midline at the Krohn stage, considerably earlier than metamorphosis. During metamorphosis, the larval nervous system was not incorporated into the adult nervous system. These observations strongly suggest that the hemichordate larval nervous system contributes little to the newly formed adult nervous system.     

Performance evaluation of ethanol fermentor systems using a vector-valued objective function

It is shown that the performance evaluation using a vector-valued objection function whose components are the product productivity, the product concentration, and the substrate conversion is quite useful in getting deeper insight into the development of new processes and in determining the operating point. Particular attention is focused on the ethanol fermentation using variety of systems such as the conventional chemostat system, multiple fermentor system, cell recycle system, extractive fermentor system, cell recycle system, extractive fermentor system, and immobilized cell system. The contour map and the projection of the noninferior set are used in investigating the performance improvement and the trade-offs among performance indexes.     

Co-expression of a prophage system and a plasmid system in Bacillus subtilis

A dual expression system for overexpressing two proteins by a single cell strain has been developed in Bacillus subtilis. This dual expression system combines the phi105MU331 prophage system and a plasmid system within a single cell. Protein expression by the prophage system is heat inducible, while that of the plasmid system is constitutive. Three candidate genes, BPN, BT, and amyE, all of Bacillus origin, were used as test models. Seven strains (BPN, BT, AMY, BS168K, MU331K, BPNK, and BTK) were constructed to investigate the influences of the prophage system and the plasmid system on each other, and to compare the efficiency of the individual expression systems with that of the dual expression system. Individually, the yield of the plasmid system is higher than that of the prophage system, which could be attributed to the constitutive nature of the expression of the plasmid system. Nonetheless, for the dual expression strains, the expression of two enzymes in a single fermentation run can reduce costs in facilities, manpower, and utilities. Fed-batch fermentation of BPNK strains confirmed the feasibility of applying this dual expression system in industrial-scale production.     

Properties of a catecholaminergic system in some coelenterates. A histochemical and autoradiographic study

Properties of a catecholaminergic nervous system in a coelenterate nervous system are described. The catecholamine present shows similarities to noradrenalin but it is not identical with noradrenalin. Contrary to known vertebrate catecholaminergic systems, neither a reuptake system nor a degrading system is present in the coelenterate catecholaminergic nervous system.     

Functional organization of a photoperiodic brain system

The neurofunctional system, which receives a photoperiod, is a photoperiodic brain system. As a part of chronoperiodic system of organism it is involved in perception and transfer of information about the main external Zeitgeber to the peripheral tissues. Such role of photoperiodic system allows it not only synchronize the chronorhythms of different somatic and visceral functions, but also realize the coordination and the modulation of adaptation mechanisms to the stressors influence. The present review is focused on the ways of conduction of photoperiodic information, role of suprachiasmatic nuclei of hypothalamus in endogenous oscillation of chronorhythms and pineal gland as a neuroendocrinal transducer; and also on characteristics of circadian and circannual parts of photoperiodic system. Special attention is given to vegetative part of photoperiodic system and melatonin--"the hormone of dark". It is supposed that adenosine, one of the humoral elements of photoperiodic system, is involved in transfer of duration of the light part of photoperiod. Due to presented data we have come to the conclusion that septohippocampal system is one of the center for saving photoperiodic information.