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Venous access is needed for implantation of cardiac implantable electronic devices (CIEDs) with endocardial leads. Extrathoracic venous access in the prepectoral region has become the standard of care for CIED implantation because of lower risks for pneumothorax and likely less lead malfunction due to subclavian crush syndrome. The most common extrathoracic venous access sites in the pectoral region are extrathoracic subclavian vein access, axillary vein access, and cephalic vein access. This review provides a detailed description of the anatomy, technical considerations, and relative advantages and disadvantages of each of these extrathoracic venous access sites.

A current trend in the design of modern aero engines is the transition towards leaner combustion as a solution to satisfy increasingly stringent emission regulations. Lean combustion systems are often more susceptible to thermoacoustic instability and the fuel injector can play a critical role. This paper presents an analytical study on the unsteady air flow through a generic injector passage in response to incident acoustic waves. The injector passage is represented by a simplified geometry which comprises the main geometrical passage features. The unsteady flow through the passage is obtained by combining the elemental solutions for different parts of the passage. This enables the transfer impedance of the injector passage to be determined and the effects of different design parameters on the sensitivity of the air flow to acoustic perturbations to be examined. The convective wave associated with the unsteady swirl vane wakes is also visited and compared with the results from the numerical simulations obtained in previous works. In addition to helping derive design practices for injector passages from the perspective of thermoacoustic instability, the current analysis can also be applied as a preliminary design tool to assess the acoustic characteristics for an injector passage of the axial swirler type.

The acoustic characteristics of bluff-body burners play a critical role in the combustion stability for combustors using this type of burners. The acoustic modelling of an axisymmetric bluff-body burner entails properly capturing the sound-vortex interaction for the flow through the annular aperture of the burner. Such a problem pertaining to annular apertures can also be of relevance to other engineering applications, such as acoustic dampers or turbofan duct systems. The methodology of combining suitable acoustic Green’s functions with a vortex sheet model has been applied extensively in previous theoretical studies of the acoustic response of a short circular orifice with a mean flow passing through it. In this work, the Green’s function and vortex sheet model theory is generalised in order to efficiently predict the acoustic characteristics of thin annular apertures sustaining a mean flow, which effectively emulate the typical axisymmetric bluff-body burner configurations in realistic combustors. This requires the incorporation of multiple Kutta conditions for modelling the vortex shedding and multiple vortex sheets for modelling the interaction of the shed vorticity and the acoustics. A high-resolution compressible Large Eddy Simulation (LES) of a simplified representative geometry is performed for validation; the analytical prediction and numerical findings show very good agreement, and the LES further provides key insights into the speed with which vortical disturbances convect downstream.

The cantilever failure is one of the typical bank failures, in which the lateral caving erosion at the bottom of the bank plays an important role. When the caving erosion width is larger than a certain value, the cantilever failures such as shear, toppling and stress failures may occur. In order to understand the condition of the cantilever failure, the collapse mechanisms of the cantilever failures are studied based on the bank stability theory and flume experiment. According to the bank stability equation with the lateral erosion, the critical caving erosion width (CCEW) formulas for the shear and toppling failures of simple slope bank were derived in this paper. The formulas show that the CCEW increases as the overhanging soil thickness and soil cohesion increase, and decreases as the crack depth on the bank surface and the slope angle of the bank increase. And these formulas were tested with experimental data, which shows the predicted values are good agreement with experimental data. The paper reveals a quantitative expression on the process of the river cantilever failure.

Cocaine HCl is well known for its toxic effects on the cardiovascular system, but little is known about its effects on different regional blood vessels. We designed experiments to determine if cocaine HCl could influence the tension of isolated aortic rings, i.e., induce contraction or relaxation. Surprisingly, cocaine HCl (1 x 10(-5) to 6 x 10(-3) M) relaxed isolated aortic rings precontracted by phenylephrine in a concentration-dependent manner. No significant differences were found between intact or denuded isolated aortic rings (P0.05). The maximal % relaxations of intact vs. denuded isolated aortic rings were 108.9+/-24.3% vs. 99.5+/-8.3% (P0.05). Cocaine HCl, 2 x 10(-3) M, was found to inhibit contractions by phenylephrine; EC50s were increased (P0.01) and Emax's were decreased (51.3+/-16.4% vs. 89.8+/-10.6%, P0.01). A variety of amine antagonists could not inhibit the relaxant effects of cocaine HCl (P0.05). The cyclooxygenase-1 inhibitor, indomethacin, also failed to inhibit relaxations induced by cocaine HCl (P0.05). Neither L-arginine, NG-monomethyl-L-arginine (L-NMMA), nor methylene blue could inhibit the relaxations induced by cocaine HCl (P0.05), suggesting cocaine HCl does not relax isolated aortic rings by inducing the synthesis or release of nitric oxide (NO) or prostanoids from either endothelial or vascular muscle cells. Inhibitors of cAMP, cGMP and protein kinase G (PKG) also failed to inhibit cocaine-induced relaxations. Cocaine HCl (1 x 10(-5) to 6 x 10(-3) M) could also relax isolated aortic rings precontracted by phenylephrine in high K+ depolarizing buffer. Surprisingly, calyculin A, an inhibitor of myosin light chain (MLC) phosphatase, inhibited cocaine-induced relaxations in a concentration-dependent manner, suggesting the probable importance of cocaine-induced MLC phosphatase activation in rat aortic smooth muscle cells. It was also found that cocaine HCl could dose-dependently inhibit Ca2+-induced contractions of isolated aortic rings in high K+-Ca2+-free buffer, suggesting that cocaine HCl may inhibit Ca2+ influx and/or intracellular release.

Recently, reactive oxygen species (ROS) have been suggested as important mediators of brain damage in a number of disease states, including traumatic brain injury, neurodegenerative diseases and strokes. Apoptosis has been suggested to play an important role in neurodegenerative diseases, traumatic brain injury and strokes. The aim of this study was to determine whether or not cerebral vascular smooth muscle cells (CVSMCs) undergo apoptosis following treatment with hydrogen peroxide (H2O2). Herein, we demonstrate, for the first time, that H2O2 can induce apoptosis in a concentration-dependent manner in primary cultured CVSMCs, as measured by several morphological and biochemical criteria. H2O2-induced apoptosis may be initiated by stimulating Ca2+-dependent endonuclease activity. The present new data suggest that apoptosis in cerebral VSMCs, induced by ROS, such as H2O2, could play important roles in neruodegenerative processes, traumatic brain injury and strokes.