941 resultados para cellular transport system
Resumo:
In the Jakarta Metropolitan Region (JMR), the lack of co-ordination and appropriate governance has resulted in paralyzing traffic jams at the metropolitan scale that cannot be resolved by a single government entity. The issue of metropolitan governance is especially crucial here as the JMR lacks an established and formally pre-designed system of governance (e.g., in a constitution or other legal regulations). Instead, it relies on the interaction, coordination and cooperation of a multitude of different stakeholders, ranging from local and regional authorities to private entities and citizens. This chapter offers a discussion on the various governance approaches relating to an appropriate institutional design required for transportation issues at the metropolitan scale. The case used is a regional Bus Rapid Transit (BRT) system as an extension to the metropolitan transport system. Institutional design analysis is applied to the case and three possible improvements - i) a ‘Megapolitan’ concept, ii) a regional spatial plan and iii) inter-local government cooperation; were identified that correspond to current debates on metropolitan governance approaches of regionalism, localism and new regionalism. The findings, which are relevant to similar metropolitan regions, suggest that i) improvements at the meso-level of institutional design are more readily accepted and effective than improvements at the macro-level and ii) that the appropriate institutional design for governing metropolitan transportation in the JMR requires enhanced coordination and cooperation amongst four important actors - local governments, the regional agency, the central government, and private companies.
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In industrial plants, oil and oil compounds are usually transported by closed pipelines with circular cross-section. The use of radiotracers in oil transport and processing industrial facilities allows calibrating flowmeters, measuring mean residence time in cracking columns, locate points of obstruction or leak in underground ducts, as well as investigating flow behavior or industrial processes such as in distillation towers. Inspection techniques using radiotracers are non-destructive, simple, economic and highly accurate. Among them, Total Count, which uses a small amount of radiotracer with known activity, is acknowledged as an absolute technique for flow rate measurement. A viscous fluid transport system, composed by four PVC pipelines with 13m length (12m horizontal and 1m vertical) and ½, ¾, 1 and 2-inch gauges, respectively, interconnected by maneuvering valves was designed and assembled in order to conduct the research. This system was used to simulate different flow conditions of petroleum compounds and for experimental studies of flow profile in the horizontal and upward directions. As 198Au presents a single photopeak (411,8 keV), it was the radioisotope chosen for oil labeling, in small amounts (6 ml) or around 200 kBq activity, and it was injected in the oil transport lines. A NaI scintillation detector 2”x 2”, with well-defined geometry, was used to measure total activity, determine the calibration factor F and, positioned after a homogenization distance and interconnected to a standardized electronic set of nuclear instrumentation modules (NIM), to detect the radioactive cloud.
Resumo:
Poultry colibacillosis due to Avian Pathogenic Escherichia coli (APEC) is responsible for several extra-intestinal pathological conditions, leading to serious economic damage in poultry production. The most commonly associated pathologies are airsacculitis, colisepticemia, and cellulitis in broiler chickens, and salpingitis and peritonitis in broiler breeders. In this work a total of 66 strains isolated from dead broiler breeders affected with colibacillosis and 61 strains from healthy broilers were studied. Strains from broiler breeders were typified with serogroups O2, O18, and O78, which are mainly associated with disease. The serogroup O78 was the most prevalent (58%). All the strains were checked for the presence of 11 virulence genes: 1) arginine succinyltransferase A (astA); ii) E. coli hemeutilization protein A (chuA); iii) colicin V A/B (cvaA/B); iv) fimbriae mannose-binding type 1 (fimC); v) ferric yersiniabactin uptake A (fyuA); vi) iron-repressible high-molecular-weight proteins 2 (irp2); vii) increased serum survival (iss); viii) iron-uptake systems of E. coli D (iucD); ix) pielonefritis associated to pili C (papC); x) temperature sensitive haemaglutinin (tsh), and xi) vacuolating autotransporter toxin (vat), by Multiplex-PCR. The results showed that all genes are present in both commensal and pathogenic E. coli strains. The iron uptake-related genes and the serum survival gene were more prevalent among APEC. The adhesin genes, except tsh, and the toxin genes, except astA, were also more prevalent among APEC isolates. Except for astA and tsh, APEC strains harbored the majority of the virulence-associated genes studied and fimC was the most prevalent gene, detected in 96.97 and 88.52% of APEC and AFEC strains, respectively. Possession of more than one iron transport system seems to play an important role on APEC survival.
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El porvenir social y económico de una ciudad depende, en gran medida, de la eficiencia de su sistema de transporte; esto se ve reflejado en la capacidad de transportar personas y bienes de una forma sostenible, con los recursos disponibles. En la actualidad se encuentran en desarrollo sistemas de transporte masivo tipo Bus Rapid Transit [BRT] en siete ciudades colombianas, situación que genera la necesidad de dar seguimiento a su progreso y al crecimiento de su participación en la demanda de viajes unipersonales. El siguiente trabajo busca, a través de una simulación en dinámica de sistemas, describir el desarrollo de un sistema de transporte masivo, con el fin de otorgar una visión acerca del impacto de los parámetros operativos y la reinversión en el sistema y en el desarrollo e incremento de su demanda. Se plantean tres escenarios para evaluar diferentes políticas operativas y de reinversión en el sistema, analizando el comportamiento en su desarrollo.
Resumo:
Purpose: To determine the progress in Umeå concerning the furtherance of bicycle traffic in the city and to investigate the possibility of a similar progress in Jönköping. Method: Semi structured interviews with officials, politicians and enthusiasts in Umeå and Jönköping, document analysis of documents provided by the municipalities and observations of Umeå city center. Findings: Umeå’s mindset around a sustainable society have been identified and the vast difference between the two cities is the time that they’ve actively worked with the bike issue and how public officials prioritize while planning. Umeå’s large advantage in their decision making is that officials and politicians are working towards the same goal and are united in the bike issue. This makes decisions regarding bicycle promotion easier to make. Due to the difference in conditions between the cities, the writers states that Umeå’s way of planning their traffic not necessarily is the right way for Jönköping to plan theirs. Implications: In order to develop it’s bicycle network, Jönköping must dare to let go of their old way of thinking. Instead of thinking that car traffic is necessary in a city, they should have the courage to take difficult decisions that benefit bicycle promotion and thus develop a sustainable transport system. Limitations: The study does not address the economic aspects that are involved in the development of an attractive bicycle network. Also the environmental issues are only dealt with in a thorough level, as it’s necessary to fulfill the study’s objectives. The study’s purpose is considered to be achieved but the result could have been even more developed if more parties were interviewed. Keywords: Bicycle path, bicycle, sustainable transport planning, sustainable society, sustainability, Umeå, Jönköping
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This essay is an ecocritical literary analysis of the novel Solar. The aim is to investigate the effect on the reader of the main characters, place, symbols and satire with focus on climate change and sustainability. The protagonist Michael Beard, a despicable, selfish antihero, consumes everything and everybody whereas Tom Aldous, the heroic character, is devoted to a life of sustainability. Beard represents the greedy capitalistic Western consumer society and its male leaders who close their eyes to the warnings of a changing climate, and Aldous represents the sustainable and alternative lifestyle. Humor and ridicule exhibits the weaknesses and greed of mankind in a satirical way. Symbols like cancer and the Co2 emitting transport system symbolize overconsumption and a stressed globe. The effect on the reader is a reflection about the ongoing struggle between climate change and sustainability and the demand for a change towards a sustainable lifestyle.
Resumo:
The brain is well protected against microbial invasion by cellular barriers, such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). In addition, cells within the central nervous system (CNS) are capable of producing an immune response against invading pathogens. Nonetheless, a range of pathogenic microbes make their way to the CNS, and the resulting infections can cause significant morbidity and mortality. Bacteria, amoebae, fungi, and viruses are capable of CNS invasion, with the latter using axonal transport as a common route of infection. In this review, we compare the mechanisms by which bacterial pathogens reach the CNS and infect the brain. In particular, we focus on recent data regarding mechanisms of bacterial translocation from the nasal mucosa to the brain, which represents a little explored pathway of bacterial invasion but has been proposed as being particularly important in explaining how infection with Burkholderia pseudomallei can result in melioidosis encephalomyelitis.
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The exchange of proteins and lipids between the trans-Golgi network (TGN) and the endosomal system requires multiple cellular machines, whose activities are coordinated in space and time to generate pleomorphic, tubulo-vesicular carriers that deliver their content to their target compartments. These machines and their associated protein networks are recruited and/or activated on specific membrane domains where they select proteins and lipids into carriers, contribute to deform/elongate and partition membrane domains using the mechanical forces generated by actin polymerization or movement along microtubules. The coordinated action of these protein networks contributes to regulate the dynamic state of multiple receptors recycling between the cell surface, endosomes and the TGN, to maintain cell homeostasis as exemplified by the biogenesis of lysosomes and related organelles, and to establish/maintain cell polarity. The dynamic assembly and disassembly of these protein networks mediating the exchange of membrane domains between the TGN and endosomes regulates cell-cell signalling and thus the development of multi-cellular organisms. Somatic mutations in single network components lead to changes in transport dynamics that may contribute to pathological modifications underlying several human diseases such as mental retardation.
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Engineered tissue grafts, which mimic the spatial variations of cell density and extracellular matrix present in native tissues, could facilitate more efficient tissue regeneration and integration. We previously demonstrated that cells could be uniformly seeded throughout a 3D scaffold having a random pore architecture using a perfusion bioreactor2. In this work, we aimed to generate 3D constructs with defined cell distributions based on rapid prototyped scaffolds manufactured with a controlled gradient in porosity. Computational models were developed to assess the influence of fluid flow, associated with pore architecture and perfusion regime, on the resulting cell distribution.
Resumo:
The functional properties of cartilaginous tissues are determined predominantly by the content, distribution, and organization of proteoglycan and collagen in the extracellular matrix. Extracellular matrix accumulates in tissue-engineered cartilage constructs by metabolism and transport of matrix molecules, processes that are modulated by physical and chemical factors. Constructs incubated under free-swelling conditions with freely permeable or highly permeable membranes exhibit symmetric surface regions of soft tissue. The variation in tissue properties with depth from the surfaces suggests the hypothesis that the transport processes mediated by the boundary conditions govern the distribution of proteoglycan in such constructs. A continuum model (DiMicco and Sah in Transport Porus Med 50:57-73, 2003) was extended to test the effects of membrane permeability and perfusion on proteoglycan accumulation in tissue-engineered cartilage. The concentrations of soluble, bound, and degraded proteoglycan were analyzed as functions of time, space, and non-dimensional parameters for several experimental configurations. The results of the model suggest that the boundary condition at the membrane surface and the rate of perfusion, described by non-dimensional parameters, are important determinants of the pattern of proteoglycan accumulation. With perfusion, the proteoglycan profile is skewed, and decreases or increases in magnitude depending on the level of flow-based stimulation. Utilization of a semi-permeable membrane with or without unidirectional flow may lead to tissues with depth-increasing proteoglycan content, resembling native articular cartilage.