Filamentous phage f1 is exported from its Escherichia coli host without killing the bacterial cell. Phage-encoded protein pIV, which is required for phage assembly and secretion, forms large highly conductive channels in the outer membrane of E. coli. It has been proposed that the phage are extruded across the bacterial outer membrane through pIV channels. To test this prediction, we developed ...

Multi-dimensional and transient flows play a key role in many areas of science, engineering, and health sciences but are often not well understood. The complex nature of these flows may be studied using particle image velocimetry (PIV), a laser-based imaging technique for optically accessible flows. Though many forms of PIV exist that extend the technique beyond the original planar two-componen...

This paper presents PARPIV, the design and prototyping of a highly parameterized digital Particle Image Velocimetry (PIV) system implemented on reconfigurable hardware. Despite many improvements to PIV methods over the last twenty years, PIV postprocessing remains a computationally intensive task. It becomes a serious bottleneck as camera acquisition rates reach 1000 frames per second. Besides,...

PURPOSE We evaluated the efficacy and safety of emergency department technicians' (EDT) use of ultrasound (US) guided peripheral intravenous (PIV) access compared to the traditional approach on a subset of patients with difficult IV access. METHODS We enrolled a convenience sample of 75 ED patients with difficult IV access (at least 2 failed PIV attempts). During phase I, EDTs used the standa...

Here we describe the implementation of a large-scale multicamera particle image velocity (PIV) measurement to resolve the large range of spatial scales prevalent in moderate to high Reynolds number turbulent boundary layers. The objective of these experiments is to capture instantaneous snapshots of recently discovered large coherent structures which are known to inhabit the log and outer regio...

In order to research into the cytology mechanism of anti-virus action of total flavone of Scutellaria barbata (TFSB), the effects of TFSB on host cells membrane potential, Na(+)-K(+)-ATPase activity and membrane fluidity after parainfluenza virus type1 (PIV-1) infection were studied. The changes of membrane potential which was fluorescent labeled with DiBAC4(3) and its changes were measured by ...

MHC class II is expressed in restricted lineages and is modulated in response to pathogens and inflammatory stimuli. This expression is controlled by MHC CIITA, which is transcribed from multiple promoters. Although factors required for induction of CIITA are well characterized, less is known about the mechanisms leading to repression of this gene. During plasma cell differentiation, B lymphocy...

BACKGROUND Studies have identified hemodynamic shear stress as an important determinant of endothelial function and atherosclerosis. In this study, we assess the influences of hemodynamic shear stress on carotid plaques. METHODS Carotid stenosis phantoms with three severity (30, 50, 70%) were made from 10% polyvinyl alcohol (PVA) cryogel. The phantoms were placed in a pulsatile flow loop with...

A technique to enhance the reconstruction quality and consequently the accuracy of the velocity vector field obtained in Tomo-PIV experiments is presented here. The methodology involves detecting and eliminating spurious outliers in the reconstructed intensity field (ghost particles). A simulacrum matching-based reconstruction enhancement (SMRE) technique is proposed, which utilizes the charact...

Community respiratory viruses are significant causes of morbidity and mortality in patients with leukemia and hematopoietic stem cell transplant (HSCT) recipients. Data on characteristics and outcomes of parainfluenza virus (PIV) infections in these patients are limited. We reviewed the records of patients with leukemia and HSCT recipients who developed PIV infections to determine the character...