60 research outputs found
Turbulent shear layers in confining channels
We present a simple model for the development of shear layers between
parallel flows in confining channels. Such flows are important across a wide
range of topics from diffusers, nozzles and ducts to urban air flow and
geophysical fluid dynamics. The model approximates the flow in the shear layer
as a linear profile separating uniform-velocity streams. Both the channel
geometry and wall drag affect the development of the flow. The model shows good
agreement with both particle-image-velocimetry experiments and computational
turbulence modelling. The low computational cost of the model allows it to be
used for design purposes, which we demonstrate by investigating optimal
pressure recovery in diffusers with non-uniform inflow
Incidence and Tracking of Escherichia coli O157:H7 in a Major Produce Production Region in California
Fresh vegetables have become associated with outbreaks caused by Escherichia coli O157:H7 (EcO157). Between 1995–2006, 22 produce outbreaks were documented in the United States, with nearly half traced to lettuce or spinach grown in California. Outbreaks between 2002 and 2006 induced investigations of possible sources of pre-harvest contamination on implicated farms in the Salinas and San Juan valleys of California, and a survey of the Salinas watershed. EcO157 was isolated at least once from 15 of 22 different watershed sites over a 19 month period. The incidence of EcO157 increased significantly when heavy rain caused an increased flow rate in the rivers. Approximately 1000 EcO157 isolates obtained from cultures of>100 individual samples were typed using Multi-Locus Variable-number-tandem-repeat Analysis (MLVA) to assist in identifying potential fate and transport of EcO157 in this region. A subset of these environmental isolates were typed by Pulse Field Gel Electrophoresis (PFGE) in order to make comparisons with human clinical isolates associated with outbreak and sporadic illness. Recurrence of identical and closely related EcO157 strains from specific locations in the Salinas and San Juan valleys suggests that transport of the pathogen is usually restricted. In a preliminary study, EcO157 was detected in water at multiple locations in a low-flow creek only within 135 meters of a point source. However, possible transport up to 32 km was detected during periods of higher water flow associated with flooding. During the 2006 baby spinach outbreak investigation, transport was also detected where water was unlikely to be involved. These results indicate that contamination of the environment is a dynamic process involving multiple sources and methods of transport. Intensive studies of the sources, incidence, fate and transport of EcO157 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for human illness
Rheumatoid arthritis: pathological mechanisms and modern pharmacologic therapies.
Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that primarily affects the lining of the synovial joints and is associated with progressive disability, premature death, and socioeconomic burdens. A better understanding of how the pathological mechanisms drive the deterioration of RA progress in individuals is urgently required in order to develop therapies that will effectively treat patients at each stage of the disease progress. Here we dissect the etiology and pathology at specific stages: (i) triggering, (ii) maturation, (iii) targeting, and (iv) fulminant stage, concomitant with hyperplastic synovium, cartilage damage, bone erosion, and systemic consequences. Modern pharmacologic therapies (including conventional, biological, and novel potential small molecule disease-modifying anti-rheumatic drugs) remain the mainstay of RA treatment and there has been significant progress toward achieving disease remission without joint deformity. Despite this, a significant proportion of RA patients do not effectively respond to the current therapies and thus new drugs are urgently required. This review discusses recent advances of our understanding of RA pathogenesis, disease modifying drugs, and provides perspectives on next generation therapeutics for RA
Заинтересованный разговор о будущем философии и социальной ответственности философов
Copyright Springer. [Full text of this article is not available in the UHRA]Peer reviewe
Identification of Malassezia species from Tunisian patients with pityriasis versicolor and normal subjects
Effects of extracellular K+ and Ca2+ on membrane potential, contraction and86Rb+ efflux in guinea-pig mesotubarium
Thigh-length compression stockings and DVT after stroke
Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease
Two high-voltage-activated, dihydropyridine-sensitive Ca2+ channel currents with distinct electrophysiological and pharmacological properties in cultured rat aortic myocytes
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