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Effective Mechanism (effective + mechanism)
Selected AbstractsAttenuation of retinal vascular development and neovascularization in transgenic mice over-expressing thrombospondin-1 in the lensDEVELOPMENTAL DYNAMICS, Issue 7 2006Zhifeng Wu Abstract Thrombospondin-1 (TSP1) is an endogenous inhibitor of angiogenesis and induces endothelial cell (EC) apoptosis. To study the role TSP1 plays during vascular development and neovascularization, we assessed the effects of ectopic TSP1 expression in the lens on retinal vascularization in transgenic mice. The TSP1 over-expressing mice showed abnormalities in the development of retinal vasculature. There was a dramatic decrease in the density of superficial and deep vascular plexuses of the retina in transgenic mice. The retinal vessels in TSP1 transgenic mice also appeared nonuniform and abnormal in maturation. We detected an increase in the number of EC undergoing apoptosis, which was compensated, in part, by an increase in cell proliferation in retinal vasculature of TSP1 transgenic mice. The TSP1 transgenic mice also exhibited increased levels of vessel obliteration and a limited preretinal neovascularization during oxygen-induced ischemic retinopathy (OIR). Our results indicate increased expression of TSP1 attenuates normal retinal vascularization and preretinal neovascularization during OIR. Therefore, modulation of TSP1 expression may provide an effective mechanism for regulation of ocular angiogenesis. Developmental Dynamics 235:1908,1920, 2006. © 2006 Wiley-Liss, Inc. [source] Schooling and migration of large pelagic fishes relative to environmental cuesFISHERIES OCEANOGRAPHY, Issue 2 2000Robert Humston A kinesis model driven by high-resolution sea surface temperature maps is used to simulate Atlantic bluefin tuna movements in the Gulf of Maine during summer months. Simulations showed that individuals concentrated in areas of thermal preference. Results are compared to empirical distribution maps of bluefin tuna schools determined from aerial overflights of the stock during the same time periods. Simulations and empirical observations showed similar bluefin tuna distributions along fronts, although interannual variations in temperature ranges occupied suggest that additional foraging factors are involved. Performance of the model is further tested by simulating the relatively large-scale annual north,south migrations of bluefin tuna that followed a preferred thermal regime. Despite the model's relatively simple structure, results suggest that kinesis is an effective mechanism for describing movements of large pelagic fish in the expansive ocean environment. [source] Systematic review of the effectiveness of integrated care pathways: what works, for whom, in which circumstances?INTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 2 2009Davina Allen RGN BA(Hons) PhD Abstract Aim, Integrated care pathways (ICP) are management technologies which formalise multidisciplinary team-working and enable professionals to examine their roles and responsibilities. ICPs are now being implemented across international healthcare arena, but evidence to support their use is equivocal. The aim of this study was to identify the circumstances in which ICPs are effective, for whom and in what contexts. Methods, A systematic review of high-quality randomised controlled trials published between 1980 and 2008 (March) evaluating ICP use in child and adult populations in the full range of healthcare settings. Results 1For relatively predictable trajectories of care ICPs can be effective in supporting proactive care management and ensuring that patients receive relevant clinical interventions and/or assessments in a timely manner. This can lead to improvements in service quality and service efficiency without adverse consequences for patients. 2ICPs are an effective mechanism for promoting adherence to guidelines or treatment protocols thereby reducing variation in practice. 3ICPs can be effective in improving documentation of treatment goals, documentation of communication with patients, carers and health professionals. 4ICPs can be effective in improving physician agreement about treatment options. 5ICPs can be effective in supporting decision-making when they incorporate a decision-aide. 6The evidence considered in this review indicates that ICPs may be particularly effective in changing professional behaviours in the desired direction, where there is scope for improvement or where roles are new. 7Even in contexts in which health professionals are already experienced with a particular pathway, ICP use brings additional beneficial effects in directing professional practice in the desired direction. 8ICPs may be less effective in bringing about service quality and efficiency gains in variable patient trajectories. 9ICPs may be less effective in bringing about quality improvements in circumstances in which services are already based on best evidence and multidisciplinary working is well established. 10Depending on their purpose, the benefits of ICPs may be greater for certain patient subgroups than others. 11We do not know whether the costs of ICP development and implementation are justified by any of their reported benefits. 12ICPs may need supporting mechanisms to underpin their implementation and ensure their adoption in practice, particularly in circumstances in which ICP use is a significant change in organisational culture. 13ICP documentation can introduce scope for new kinds of error. Conclusions, ICPs are most effective in contexts where patient care trajectories are predictable. Their value in settings in which recovery pathways are more variable is less clear. ICPs are most effective in bringing about behavioural changes where there are identified deficiencies in services; their value in contexts where inter-professional working is well established is less certain. None of the studies reviewed included an economic evaluation and thus it is not known whether their benefits justify the costs of their implementation. [source] Return Migration and the Problem of ReintegrationINTERNATIONAL MIGRATION, Issue 5 2000Oladele O. Arowolo This article proposes a programme approach for achieving the social and economic reintegration of all categories of return migrants. As former exiles who have returned to their country of origin are no longer refugees, some government agencies need to organize the reception of, and provide assistance to, returnees. But without long-term planning, ad hoc committees are unable to be effective facilitators of the reintegration process. The article suggests a list of major elements necessary for an effective reintegration programme, and argues that governments should focus on the institutional mechanism of programme management, including the creation of a responsible agency or agencies. The management structure should be based in the National Planning Ministry of government. Establishment of an effective mechanism would be likely to inspire donor confidence; and ,homecoming' would no longer be a nightmare for potential returnees trying to reintegrate. [source] Constructivist Implications of Material Power: Military Engagement and the Socialization of States, 1972,2000INTERNATIONAL STUDIES QUARTERLY, Issue 3 2006CAROL ATKINSON The research presented in this article examines one aspect of state socialization, the extent to which transnational military-to-military interactions have served as an effective mechanism of the democratic political socialization of states. Military organizations are very interesting when we consider avenues by which state socialization might occur because military organizations are an influential part of governments, and members share common beliefs and values as soldiers and officers that transcend borders. Thus, it would seem that a state's military structure is one likely channel whereby politically relevant individuals might learn new ideas and have the capability to reform existing institutional structures. The socialization process described in this study is three level: (1) individuals acquire new ideas; (2) coercion, incentives, and persuasion aid in institutionalizing these ideas in the underlying political structure of the state; and (3) once institutionalized, these new ideas/identity of the state influence the material and ideational structure of international society. Using Cox Proportional Hazard models and an original data set encompassing over 160 states during the years 1972,2000, the analyses find U.S. military-to-military contacts to be positively and systematically associated with liberalizing trends. This finding provides evidence that constructivist mechanisms do have observable effects, and that ideationally based processes play an important role in U.S. national security. [source] Geology of the Kokchetav UHP-HP metamorphic belt, Northern KazakhstanISLAND ARC, Issue 3 2000Y. Kaneko Abstract Ultrahigh-pressure metamorphic (UHPM) rocks of the Kokchetav Massif of Kazakhstan contain metamorphic microdiamond and coesite inclusions inside rigid capsules such as garnet and zircon. Precambrian protoliths of the UHPM rocks were metamorphosed at around 530 Ma, at pressures of about 7 GPa, which suggests that crustal protoliths were subducted to depths of over 200 km. Primary UHPM minerals are poorly preserved due to partial obliteration by subsequent Barrovian overprint during exhumation and later collision events in Caledonian times. We report the results of detailed mapping of the Kokchetav Massif and use structural data to propose intrusion and exhumation mechanisms for the UHPM rocks. Detailed mapping revealed that many subvertical structures in the ultrahigh-pressure,high-pressure (UHP,HP) units were formed due to later folding. The primary structure appears to be subhorizontal and the total thickness of the UHP rocks is estimated at around 2 km. The first order structure is sandwich-like; that is, the UHP,HP units are separated from underlying low-P metamorphic rocks of the Daulet Series and from feebly metamorphosed to unmetamorphosed sedimentary strata on the top by subhorizontal faults. Kinematic indicators show top-to-the-south sense of shear along the top, and top-to-the-north displacement along the bottom boundaries. These shear senses, together with the observed metamorphic gradients, suggest that the thin UHPM sheet was extruded toward the north. We consider wedge extrusion to have been the most effective mechanism for the exhumation of the UHPM rocks. [source] The persistent-access-caching algorithm,RANDOM STRUCTURES AND ALGORITHMS, Issue 2 2008Predrag R. Jelenkovi Abstract Caching is widely recognized as an effective mechanism for improving the performance of the World Wide Web. One of the key components in engineering the Web caching systems is designing document placement/replacement algorithms for updating the collection of cached documents. The main design objectives of such a policy are the high cache hit ratio, ease of implementation, low complexity and adaptability to the fluctuations in access patterns. These objectives are essentially satisfied by the widely used heuristic called the least-recently-used (LRU) cache replacement rule. However, in the context of the independent reference model, the LRU policy can significantly underperform the optimal least-frequently-used (LFU) algorithm that, on the other hand, has higher implementation complexity and lower adaptability to changes in access frequencies. To alleviate this problem, we introduce a new LRU-based rule, termed the persistent-access-caching (PAC), which essentially preserves all of the desirable attributes of the LRU scheme. For this new heuristic, under the independent reference model and generalized Zipf's law request probabilities, we prove that, for large cache sizes, its performance is arbitrarily close to the optimal LFU algorithm. Furthermore, this near-optimality of the PAC algorithm is achieved at the expense of a negligible additional complexity for large cache sizes when compared to the ordinary LRU policy, since the PAC algorithm makes the replacement decisions based on the references collected during the preceding interval of fixed length. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008 [source] Restoration of Species Richness in Abandoned Mediterranean Grasslands: Seeds in Cattle DungRESTORATION ECOLOGY, Issue 3 2003Juan Traba Abstract Endozoochory has proven to be a highly effective mechanism in the dispersal of viable seeds in Mediterranean grasslands. We studied the effect of cattle dung application on species richness, particularly on the reintroduction of species lost after abandonment. Sown and control plots were monitored for 3 years after dung sowing. We found a significant increase in small-scale richness, which may be attributed to the treatment, with the inclusion of species detected in the dung and in the grazed pasture. The differences in richness and floristic composition diminished over time. This experiment proves the potential utility of this treatment for the restoration of species richness in abandoned pastures, although supplementary steps are necessary, including further sowing and/or shrub cutting in subsequent years. [source] Action Mechanisms of the Secondary Metabolite Euplotin C: Signaling and Functional Role in EuplotesTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 5 2008FRANCESCA TRIELLI ABSTRACT. Among secondary metabolites, the acetylated hemiacetal sesquiterpene euplotin C has been isolated from the marine, ciliated protist Euplotes crassus, and provides an effective mechanism for reducing populations of potential competitors through its cytotoxic properties. However, intracellular signaling mechanisms and their functional correlates mediating the ecological role of euplotin C are largely unknown. We report here that, in E. vannus (an Euplotes morphospecies that does not produce euplotin C and shares with E. crasssus the same interstitial habitat), euplotin C rapidly increases the intracellular concentration of both Ca2+ and Na+, suggesting a generalized effect of this metabolite on cation transport systems. In addition, euplotin C does not induce oxidative stress, but modulates the electrical properties of E. vannus through an increase of the amplitude of graded action potentials. These events parallel the disassembling of the ciliary structures, the inhibition of cell motility, the occurrence of aberrant cytoplasmic vacuoles, and the rapid inhibition of phagocytic activity. Euplotin C also increases lysosomal pH and decreases lysosomal membrane stability of E. vannus. These results suggest that euplotin C exerts a marked disruption of those homeostatic mechanisms whose efficiency represents the essential prerequisite to face the challenges of the interstitial environment. [source] Early cortical lens opacities: a short overviewACTA OPHTHALMOLOGICA, Issue 6 2009Gijs F.J.M. Vrensen Abstract. Cataract is still the dominant cause of blindness worldwide. Cortical cataract is the most prevalent of the age-related changes in the human lenses that require surgical intervention to restore vision. The absence of adequate cataract surgery in most developing countries is the main cause of the high prevalence of cataract blindness worldwide. Lens ageing is accompanied by dramatic increases in stiffness, light scattering and coloration of the lens nucleus. These changes start to become manifest as early as the fourth or fifth decade of life and lead to nuclear cataract in old age. In the same period the equatorial deep lens cortex starts to show small opaque shades, which eventually grow out to segmental and annular opacities. These opaque shades are filled with small vesicles and contain abnormal amounts of cross-linked proteins, cholesterol and phospholipids. They are bordered by membranes that are rich in square arrays, have ,degenerate' gap junctions and have few intramembranous particles. It has been shown that the opaque shades represent cohorts of locally affected fibres segregated from unaffected neighbouring fibres by ,non-leaky' membranes. This segregation is an effective mechanism delaying the outgrowth of these opacities to cuneiform cataracts entering the pupillary space and thus leading to blinding cortical cataracts. Although cataract formation is mostly considered to be a multi-factorial disease, oxidative stress might be one of the leading causes for both nuclear and cortical cataract. In cortical cataracts shear stress between cortex and nucleus during accommodation may also play a significant role. [source] The Essential Ingredients of Successful Sibling Relationships: An Emerging Framework for Advancing Theory and PracticeCHILD DEVELOPMENT PERSPECTIVES, Issue 2 2010Laurie Kramer Abstract, Although conflict is a frequent and dynamic interpersonal process in children's sibling relationships, ambivalence (i.e., combinations of, or shifts between, positive and negative behaviors and affects) may better characterize normative sibling interactions. Nonetheless, there is a general assumption that reducing conflict is the most effective mechanism for improving sibling relationships. This review argues that the focus on conflict as the predominant attribute of sibling relationships is misplaced and has served to overshadow research on other relationship processes; it has also handicapped the development of effective prevention and intervention tools. Strategies are presented for moving theory, research, and practice toward the identification and development of factors and social processes that promote prosocial forms of sibling engagement and manage conflict. Innovative strategies are needed on two fronts: to help young siblings set their relationship on a positive trajectory and to help them avoid or remediate conflictual interactions. [source] Angiotensin I-Converting Enzyme And Metabolism Of The Haematological Peptide N -Acetyl-Seryl-Aspartyl-Lysyl-ProlineCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2001Michel Azizi SUMMARY 1. Angiotensin I-converting enzyme (ACE) has two homologous active N- and C-terminal domains and displays activity towards a broad range of substrates. The tetrapeptide N -acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) has been shown to be hydrolysed in vitro by ACE and to be a preferential substrate for its N-terminal active site. This peptide reversibly prevents the recruitment of pluripotent haematopoietic stem cells and normal early progenitors into the S-phase. 2. Angiotensin I-converting enzyme inhibitors, given as a single dose to normal subjects or during long-term treatment in hypertensive patients, result in plasma AcSDKP levels five- to six-fold higher and urine concentrations 40-fold higher than those of control subjects and/or patients. Thus, AcSDKP is a natural peptide hydrolysed by the N-terminal domain of ACE in vivo. In addition, ACE may be implicated in the process of haematopoietic stem cell regulation by permanently degrading this natural circulating inhibitor of cell entry into the S-phase. 3. Besides hydrolysis by ACE, the second very effective mechanism by which AcSDKP is cleared from plasma is glomerular filtration. Because of its high sensitivity and specificity, the measurement of AcSDKP in plasma and urine provides a valuable tool in screening specific inhibitors of the N-terminal domain of ACE and in monitoring ACE inhibition during chronic treatment. 4. The long-term consequences of AcSDKP accumulation are not known. During chronic ACE inhibition in rats, AcSDKP levels slightly increase in organs with high ACE content (kidneys, lungs). To significantly increase its concentration in target haematopoietic organs (the extracellular fraction of bone marrow), AcSDKP has to be infused on top of a captopril-based treatment. 5. A selective inhibitor of the N-domain of ACE in vitro and in vivo has been identified recently. The phosphinic peptide RXP 407 does not interfere with blood pressure regulation, but does increase, dose dependently, plasma concentrations of AcSDKP in mice, in contrast with lisinopril, which affects the metabolism of both AcSDKP and angiotensin I. N-Terminal-selective ACE inhibitors may be used to selectively control AcSDKP metabolism in target haematopoietic organs. This new therapeutic strategy may be of value for protecting haematopoietic cells from the toxicity of cancer chemotherapy. [source] Object-oriented distributed computing based on remote class referenceCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 1 2003Yan Huang Abstract Java RMI, Jini and CORBA provide effective mechanisms for implementing a distributed computing system. Recently many numeral libraries have been developed that take advantage of Java as an object-oriented and portable language. The widely-used client-server method limits the extent to which the benefits of the object-oriented approach can be exploited because of the difficulties arising when a remote object is the argument or return value of a remote or local method. In this paper this problem is solved by introducing a data object that stores the data structure of the remote object and related access methods. By using this data object, the client can easily instantiate a remote object, and use it as the argument or return value of either a local or remote method. Copyright © 2003 John Wiley & Sons, Ltd. [source] Public and stakeholder participation in European water policy: a critical review of project evaluation processesENVIRONMENTAL POLICY AND GOVERNANCE, Issue 1 2006Nuno Videira Abstract The recent reform of the European water policy recognizes the importance of developing effective mechanisms to support public and stakeholder participation in river basin decision-making processes. This paper critically reviews the evaluation processes of different types of water related project in five European countries (Portugal, Greece, The Netherlands, the United Kingdom and Spain), with respect to participatory criteria. The horizontal comparison of these cases accounted for criteria such as the political and institutional context, the design, the implementation and the evaluation of the outcomes of participation. The results indicated that, in the majority of the case studies, participation was simply adopted to conform to the requisites of the Environmental Impact Assessment Directive. Thus, there was truly no room for the active involvement and collaboration of the interested parties. The development of guidelines, drawing from the analysis of past experiences, is expected to support the implementation of the participatory objectives of the EU water policy. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. [source] Predation by the tropical plant Utricularia foliosaFRESHWATER BIOLOGY, Issue 11 2006LIZANDRO SANABRIA-ARANDA Summary 1. We examined the prey captured by individual plants of the tropical carnivorous plant Utricularia foliosa, located in different areas along a creek in the Colombian Amazon and the zooplankton and macroinvertebrate communities associated with the plants. The aims were: (i) to determine whether bladders of different sizes within each plant catch different numbers of prey or exploit different size ranges and types of prey, (ii) if the quantity and composition of prey captured varies temporally and/or spatially and (iii) if the plant has evolved effective mechanisms of attracting prey. 2. Utricularia foliosa captured the most abundant species of macroinvertebrates associated with the plant. Larger bladders captured more, larger and more diverse prey. However, benefits of the extra prey caught by large bladders were not offset by the greater cost of producing bladders larger than approximately 1650 ,m. 3. The number of prey captured was higher in those plants with more carbohydrates per bladder and with a higher ratio of antenna size/bladder length. The antennae enhance capture success by offering the prey a favourable substratum that exploits their natural locomotor and feeding behaviour. However, although carbohydrates may lure prey, carbohydrate production was not a strategy of the plant to enhance the capture of prey, because the amount of carbohydrates in the bladder was related to the abundance of periphyton. [source] Elder Self-Neglect and the Justice System: An Essay from an Interdisciplinary PerspectiveJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 2008Marie-Therese Connolly JD Elder self-neglect is a complex issue for the legal system,one not always easily distinguished from other types of elder abuse, neglect, and exploitation. The issue inherently implicates several disciplines, and although self-neglect is not prosecuted per se, prosecutions of other types of elder abuse, neglect, and exploitation may affect self-neglect as well. In addition, other types of legal intervention, such as guardianship actions, may serve to protect vulnerable older people, but it is critical to ensure that such interventions do not inappropriately infringe on the older person's civil liberties or result in exploitation or worse. There are daunting challenges to doing work in this field,death; ageism; medical, legal, and ethical complexities; and a chronic paucity of funding. It is nevertheless imperative that researchers expand their efforts to elucidate the nature and scope of elder self-neglect; its interplay with other forms of abuse, neglect, and exploitation; and the most effective mechanisms for intervention and prevention. Such efforts, and in particular interdisciplinary approaches to these common problems, are critical to improving care for the nation's older people and assisting millions of families and practitioners. [source] Stakeholder perspectives on new ways of delivering unscheduled health care: the role of ownership and organizational identityJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 2 2007Gill Haddow MA PhD Abstract Rationale, aims and objectives, To explore stakeholder perspectives of the implementation of a new, national integrated nurse-led telephone advice and consultation service [National Health Service 24 (NHS 24)], comparing the views of stakeholders from different health care organizations. Methods, Semi-structured interviews with 26 stakeholders including partner organizations located in primary and secondary unscheduled care settings [general practitioner (GP) out-of-hours cooperative; accident and emergency department; national ambulance service, members of NHS 24 and national policy makers. Attendance at key meetings, documentary review and email implementation diaries provided a contextual history of events with which interview data could be compared. Results, The contextual history of events highlighted a fast-paced implementation process, with little time for reflection. Key areas of partner concern were increasing workload, the clinical safety of nurse triage and the lack of communication across the organizations. Concerns were most apparent within the GP out-of-hours cooperative, leading to calls for the dissolution of the partnership. Accident and emergency and ambulance service responses were more conciliatory, suggesting that such problems were to be expected within the developmental phase of a new organization. Further exploration of these responses highlighted the sense of ownership within the GP cooperative, with GPs having both financial and philosophical ownership of the cooperative. This was not apparent within the other two partner organizations, in particular the ambulance service, which operated on a regional model very similar to that of NHS 24. Conclusions, As the delivery of unscheduled primary health care crosses professional boundaries and locations, different organizations and professional groups must develop new ways of partnership working, developing trust and confidence in each other. The results of this study highlight, for the first time, the key importance of understanding the professional ownership and identity of individual organizations, in order to facilitate the most effective mechanisms to enable that partnership working. [source] A Regulatory Analysis of International Climate Change RegulationLAW & POLICY, Issue 4 2008DONALD FEAVER The political challenges impeding the negotiation of a comprehensive multilateral agreement on international climate change have received a great deal of attention. A question that has gone somewhat overlooked is what essential components an effective regulatory scheme to reduce greenhouse gas emissions should contain. The objective of this article is to examine the regulatory architecture of current international arrangements relating to global climate change regulation. A systematic analysis of the structure, substantive composition, and administrative characteristics of the UNFCCC and Kyoto Protocol is undertaken. The analytical standard against which the agreements are examined is whether current international regulatory arrangements satisfy the basic requirements of regulatory coherence. The analysis identifies how the present scheme consists of a complex institutional structure that lacks a substantive regulatory core. The implications of the absence of functional and effective mechanisms to govern greenhouse gas emission reductions are considered in relation to the principles of good regulatory design. This, in turn, provides useful insights into how a better regulatory scheme might be designed. [source] Thellungiella halophila, a salt-tolerant relative of Arabidopsis thaliana, possesses effective mechanisms to discriminate between potassium and sodiumPLANT CELL & ENVIRONMENT, Issue 1 2004V. VOLKOV ABSTRACT Thellungiella halophila is a salt-tolerant close relative of Arabidopsis thaliana. Significant mRNA similarity was confirmed by hybridization of T. halophila mRNA with the A. thaliana GeneChip ATH1. To establish a platform for future molecular comparison of the two species several physiological mechanisms, which may confer high salt tolerance to T. halophila, were investigated. Determination of ion content in shoots and roots of A. thaliana and T. halophila indicated different strategies of ion uptake and translocation from root to shoot in the two species. During salt stress T. halophila accumulated less sodium than A. thaliana. Tissue concentrations of sodium and potassium showed negative correlation in A. thaliana but not in T. halophila. Electrophysiological experiments proved high potassium/sodium selectivity of root plasma membrane channels in T. halophila. In particular, voltage-independent currents were more selective for potassium in T. halophila than in A. thaliana. Single cell sampling of T. halophila leaves during salt exposure revealed increased concentrations of sodium and decreased concentrations of potassium in epidermal cells suggesting that this cell type could function to ensure storage of sodium and exchange of potassium with the rest of leaf. Application of salt resulted in a sharp drop of transpiration in A. thaliana. By contrast, transpiration in T. halophila responded more slowly and was only slightly inhibited by salt treatment, thus maintaining high water uptake and ion transport. [source] The tegument surface membranes of the human blood parasite Schistosoma mansoni: A proteomic analysis after differential extractionPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 5 2006Simon Braschi Abstract The blood fluke Schistosoma mansoni can live for years in the hepatic portal system of its human host and so must possess very effective mechanisms of immune evasion. The key to understanding how these operate lies in defining the molecular organisation of the exposed parasite surface. The adult worm is covered by a syncytial tegument, bounded externally by a plasma membrane and overlain by a laminate secretion, the membranocalyx. In order to determine the protein composition of this surface, the membranes were detached using a freeze/thaw technique and enriched by sucrose density gradient centrifugation. The resulting preparation was sequentially extracted with three reagents of increasing solubilising power. The extracts were separated by 2-DE and their protein constituents were identified by MS/MS, yielding predominantly cytosolic, cytoskeletal and membrane-associated proteins, respectively. After extraction, the final pellet containing membrane-spanning proteins was processed by liquid chromatographic techniques before MS. Transporters for sugars, amino acids, ions and other solutes were found together with membrane enzymes and proteins concerned with membrane structure. The proteins identified were categorised by their function and putative location on the basis of their homology with annotated proteins in other organisms. [source] Photosynthetic Eukaryotes of Freshwater Wetland Biofilms: Adaptations and Structural Characteristics of the Extracellular Matrix in the Green Alga, Cosmarium reniforme (Zygnematophyceae, Streptophyta)THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 4 2009DAVID S. DOMOZYCH ABSTRACT. Cosmarium reniforme (Zygnematophyceae, Streptophyta) is a green alga that is commonly found in biofilms of wetlands of the Adirondack region, NY (USA). Two distinctive characteristics that are critical to this alga's survival in a benthic biofilm are its elaborate cell morphology and extracellular matrix (ECM). In this study, ultrastructural, immunocytochemical, and experimental methodologies were employed in order to elucidate the cellular characteristics that are critical for survival in a biofilm. The ECM consists of a thick, outwardly lobed cell wall (CW), which contains a patterned network of structurally complex pores. Each pore consists of a narrow channel, terminating internally at a bulb that invaginates localized regions of the plasma membrane. The outer region of the pore contains arabinogalactan protein-like and extensin epitopes that are likely involved in adhesion mechanisms of the cell. External to the CW is the extracellular polymeric substance that is employed in ensheathment of the cell to the substrate and in gliding motility. The architectural design/biochemical make-up of the CW and a secretory system that encompasses the coordinated activities of the endomembrane and cytomotile/cytoskeletal systems provide the organism with effective mechanisms to support life within the biofilm complex. [source] Cross-constituency Organizing in Canadian UnionsBRITISH JOURNAL OF INDUSTRIAL RELATIONS, Issue 2 2008Linda Briskin This article explores cross-constituency organizing inside three Canadian unions that involves dual, parallel and integrated structures. It assesses these approaches with reference to the conceptual frame of intersectional political practice. In particular, this study highlights the institutionalization of intersectionality through constitutional, organizational and representational intersectionality. The paradigm of autonomy and integration is used to identify effective mechanisms for cross-constituency vehicles. Cross-constituency organizing is a form of coalition-building inside unions It is a vehicle for building solidarities across identities and advancing equity organizing in Canadian unions that supports, at one and the same time, union revitalization and the union equity project. [source] | ||||||||||||||||||||||