911 resultados para Morphological Operations


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thy-1, a cell adhesion molecule abundantly expressed in mammalian neurons, binds to a beta(3)-containing integrin on astrocytes and thereby stimulates the assembly of focal adhesions and stress fibers. Such events lead to morphological changes in astrocytes that resemble those occurring upon injury in the brain. Extracellular matrix proteins, typical integrin ligands, bind to integrins and promote receptor clustering as well as signal transduction events that involve small G proteins and cytoskeletal changes. Here we investigated the possibility that the cell surface protein Thy-1, when interacting with a beta(3)-containing integrin on astrocytes, could trigger signaling events similar to those generated by extracellular matrix proteins. DI-TNC(1) astrocytes were stimulated with Thy-1-Fc immobilized on beads, and increased RhoA activity was confirmed using an affinity precipitation assay. The effect of various inhibitors on the cellular response was also studied. The presence of Y-27632, an inhibitor of Rho kinase (p160ROCK), a key downstream effector of RhoA, significantly reduced focal adhesion and stress fiber formation induced by Thy-1. Similar effects were obtained when astrocytes were treated with C3 transferase, an inhibitor of RhoA. Alternatively, astrocytes were transfected with an expression vector encoding fusion proteins of enhanced green fluorescent protein with either the Rho-binding domain of Rhotekin, which blocks RhoA function, or the dominant-negative N19RhoA mutant. In both cases, Thy-1-induced focal adhesion formation was inhibited. Furthermore, we observed that RhoA activity after stimulation with soluble Thy-1-Fc molecule was augmented upon further cross-linking using protein A-Sepharose beads. The same was shown by cross-linking beta(3)-containing integrin with anti-beta(3) antibodies. Together, these results indicate that Thy-1-mediated astrocyte stimulation depended on beta(3) integrin clustering and the resulting increase in RhoA activity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In evaluation of soil quality for agricultural use, soil structure is one of the most important properties, which is influenced not only by climate, biological activity, and management practices but also by mechanical and physico-chemical forces acting in the soil. The purpose of this study was to evaluate the influence of conventional agricultural management on the structure and microstructure of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox) in an experimental area planted to maize. Soil morphology was described using the crop profile method by identifying the distinct structural volumes called Morphologically Homogeneous Units (MHUs). For comparison, we also described a profile in an adjacent area without agricultural use and under natural regrowth referred to as Memory. We took undisturbed samples from the main MHUs so as to form thin sections and blocks of soil for micromorphological and micromorphometrical analyses. Results from the application of the crop profile method showed the occurrence of the following structural types: loose (L), fragmented (F) and continuous (C) in both profiles analyzed. In the Memory soil profile, the fragmented structures were classified as Fptμ∆+tf and Fmt∆μ, whose micromorphology shows an enaulic-porphyric (porous) relative distribution with a great deal of biological activity as indicated by the presence of vughs and channels. Lower down, from 0.20 to 0.35 m, there was a continuous soil volume (sub-type C∆μ), with a subangular block microstructure and an enaulic-porphyric relative distribution, though in this case more compact and with aggregate coalescence and less biological activity. The micromorphometrical study of the soil of the Memory Plot showed the predominance of complex pores in NAM (15.03 %), Fmt∆μ (11.72 %), and Fptμ∆+tf (7.73 %), and rounded pores in C∆μ (8.21 %). In the soil under conventional agricultural management, we observed fragmented structures similar to the Memory Plot from 0.02 to 0.20 m, followed by a volume with a compact continuous structure (C∆μ), without visible porosity and with few roots. In the MHUs under conventional management, reduction in the packing pores (40 %) was observed, mainly in the continuous units (C). The microstructure had well-defined blocks, with the occurrence of planar pores and less evidence of biological activity. In conclusion, the morphological and micromorphological analyses of the soil profiles studied offered complementary information regarding soil structural quality, especially concerning the changes in pore types as result of mechanical stress undergone by the soil.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this research was to investigate the application of integrated risk modeling to operations and maintenance activities, specifically moving operations, such as pavement testing, pavement marking, painting, snow removal, shoulder work, mowing, and so forth. The ultimate goal is to reduce the frequency and intensity of loss events (property damage, personal injury, and fatality) during operations and maintenance activities. This report includes a literature review that identifies the current and common practices adopted by different state departments of transportation (DOTs) and other transportation agencies for safe and efficient highway operations and maintenance (O/M) activities. The final appendix to the report includes information for eight innovative O/M risk mitigation technologies/equipment and covers the following for these technologies/equipment: Appropriate conditions for deployment Performance/effectiveness, depending on hazard/activity Cost to purchase Cost to operate and maintain Availability (resources and references)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aggregate cultures of mixed glial cells, as well as of enriched astrocytes and oligodendrocytes were prepared, and maintained in serum-free medium for up to 25 days. Biochemical measurements of both neuron-specific and glia-specific enzyme activities showed that these three types of aggregate cultures were virtually devoid of neurons. Astrocyte-enriched cultures were greater than 95% pure, with oligodendrocytes as the only apparent contaminant, whereas oligodendrocyte-enriched cultures still contained a considerable proportion of astrocytes. In all these neuron-free aggregate cultures both astrocytes and oligodendrocytes attained a high degree of maturation. These findings were confirmed by morphological examinations, and by immunofluorescence studies. Furthermore, ultrastructural as well as immunocytochemical investigations using antibodies to myelin basic protein revealed that all three types of glial cell aggregate cultures contained myelin membranes, indicating that the presence of axons is not a prerequisite for the formation of myelin.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Audit report on the Operations Account of Honey Creek Resort, Moravia, Iowa as of and for the year ended June 30, 2012

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Audit report on the Honey Creek Resort Operations Account maintained by Central Group Management, LLC for the year ended June 30, 2012

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dynamic morphological transitions in thin-layer electrodeposits obtained from copper sulphate solutions have been studied. The chemical composition of the electrodeposits indicates that they appear as a consequence of the competition between copper and cuprous oxide formation. In addition, the Ohmic control of the process is verified at initial stages of the deposit growth. At higher deposit developments, gravity-induced convection currents play a role in the control of the whole process and affect the position of these transitions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The effect of hydrodynamic flow upon diffusion-limited deposition on a line is investigated using a Monte Carlo model. The growth process is governed by the convection and diffusion field. The convective diffusion field is simulated by the biased-random walker resulting from a superimposed drift that represents the convective flow. The development of distinct morphologies is found with varying direction and strength of drift. By introducing a horizontal drift parallel to the deposition plate, the diffusion-limited deposit changes into a single needle inclined to the plate. The width of the needle decreases with increasing strength of drift. The angle between the needle and the plate is about 45° at high flow rate. In the presence of an inclined drift to the plate, the convection-diffusion-limited deposit leads to the formation of a characteristic columnar morphology. In the limiting case where the convection dominates, the deposition process is equivalent to ballistic deposition onto an inclined surface.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Studies of hybrid zones can inform our understanding of reproductive isolation and speciation. Two species of brown lemur (Eulemur rufifrons and E. cinereiceps) form an apparently stable hybrid zone in the Andringitra region of south-eastern Madagascar. The aim of this study was to identify factors that contribute to this stability. We sampled animals at 11 sites along a 90-km transect through the hybrid zone and examined variation in 26 microsatellites, the D-loop region of mitochondrial DNA, six pelage and nine morphological traits; we also included samples collected in more distant allopatric sites. Clines in these traits were noncoincident, and there was no increase in either inbreeding coefficients or linkage disequilibrium at the centre of the zone. These results could suggest that the hybrid zone is maintained by weak selection against hybrids, conforming to either the tension zone or geographical selection-gradient model. However, a closer examination of clines in pelage and microsatellites indicates that these clines are not sigmoid or stepped in shape but instead plateau at their centre. Sites within the hybrid zone also occur in a distinct habitat, characterized by greater seasonality in precipitation and lower seasonality in temperature. Together, these findings suggest that the hybrid zone may follow the bounded superiority model, with exogenous selection favouring hybrids within the transitional zone. These findings are noteworthy, as examples supporting the bounded superiority model are rare and may indicate a process of ecologically driven speciation without geographical isolation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Report on a review of the operations of the Poweshiek County Sheriff’s Office for the period January 1, 2010 through March 31, 2013

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Audit report on the Honey Creek Resort Operations Account maintained by Central Group Management, LLC for the year ended June 30, 2013

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Intracardiac organization indices such as atrial fibrillation (AF) cycle length (AFCL) have been used to track the efficiency of stepwise catheter ablation (step-CA) of longstanding persistent AF, however with limited success. The morphology of AF activation waves reflects the underlying activation patterns. Its temporal evolution is a local organization indicator that could be potentially used for tracking the efficiency of step-CA. We report a new method for characterizing the structure of the temporal evolution of activation wave morphology. Using recurrence plots, novel organization indices are proposed. By computing their relative evolution during the first step of ablation vs baseline, we found that these new parameters are superior to AFCL to track the effect of step-CA "en route" to AF termination.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

One of the more severe winter hazards is ice or compacted snow on roadways. While three methods are typically used to combat ice (salting, sanding and scraping), relatively little effort has been applied to improve methods of scraping ice from roads. In this project, a new test facility has been developed, comprising a truck with an underbody blade, which has been instrumented such that the forces to scrape ice from a pavement can be measured. A test site has been used, which is not accessible to the public, and ice covers have been sprayed onto the pavement and subsequently scraped from it, while the scraping loads have been recorded. Three different cutting edges have been tested for their ice scraping efficiency. Two of the blades are standard (one with a carbide insert, the other without) while the third blade was designed under the SHRP H-204A project. Results from the tests allowed two parameters to be identified. The first is the scraping efficiency which is the ratio of vertical to horizontal force. The lower this ratio, the more efficiently ice is being removed. The second parameter is the scraping effectiveness, which is related (in some as yet unspecified manner) to the horizontal load. The higher the horizontal load, the more ice is being scraped. The ideal case is thus to have as high a horizontal load as possible, combined with the lowest possible vertical load. Results indicate that the SHRP blade removed ice more effectively than the other two blades under equivalent conditions, and furthermore, did so with greater efficiency and thus more control. Furthermore, blade angles close to 0 deg provide for the most efficient scraping for all three blades. The study has shown that field testing of plow blades is possible in controlled situations, and that blades can be evaluated using this system. The system is available for further tests as are deemed appropriate.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVE: We sought to study the epidemiologic and medical aspects of alpine helicopter rescue operations involving the winching of an emergency physician to the victim. METHODS: We retrospectively reviewed the medical and operational reports of a single helicopter-based emergency medical service. Data from 1 January 2003 to 31 December 2008 were analysed. RESULTS: A total of 921 patients were identified, with a male:female ratio of 2:1. There were 56 (6%) patients aged 15 or under. The median time from emergency call to helicopter take-off was 7 min (IQR = 5-10 min). 840 (91%) patients suffered from trauma-related injuries, with falls from heights during sports activities the most frequent event. The most common injuries involved the legs (246 or 27%), head (175 or 19%), upper limbs (117 or 13%), spine (108 or 12%), and femur (66 or 7%). Only 81 (9%) victims suffered from a medical emergency, but these cases were, when compared to the trauma victims, significantly more severe according to the NACA index (p<0.001). Overall, 246 (27%) patients had a severe injury or illness, namely, a potential or overt vital threat (NACA score between 4 and 6). A total of 478 (52%) patients required administration of major analgesics: fentanyl (443 patients or 48%), ketamine (42 patients or 5%) or morphine (7 patients or 1%). The mean dose of fentanyl was 188 micrograms (range 25-750, SD 127). Major medical interventions such as administration of vasoactive drugs, intravenous perfusions of more than 1000 ml of fluids, ventilation or intubation were performed on 39 (4%) patients. CONCLUSIONS: The severity of the patients' injuries or illnesses along with the high proportion of medical procedures performed directly on-site validates emergency physician winching for advanced life support procedures and analgesia.