Effect of spinal sympathetic blockade upon postural changes of blood flow in human peripheral tissues

The effect of head-up tilt upon subcutaneous and skeletal muscle blood flow in the crus was studied before and during epidural blockade in 10 subjects. Relative changes in blood flow were estimated by the local 133Xe washout technique. In subcutaneous tissue head-up tilt induced a decrease in blood flow of about 40% and there was no difference in the vascular response to head-up tilt before and during epidural blockade. In skeletal muscle tissue essentially the same was found as head-up tilt decreased blood flow by about 26% the response being uninfluenced by epidural blockade. In 3 patients local nervous blockade was induced by Lidocaine in 133Xe labelled subcutaneous tissue on one side. During epidural blockade and tilt blood flow increased by 12% whereas blood flow decreased by 30% on the control side. Thus epidural blockade had no influence on the vasoconstrictor response in subcutaneous tissue and skeletal muscle to head-up tilt whereas local blockade was able to prevent the response. Local mechanisms including the local veno-arteriolar reflex appear to play an important role for the observed maintenance of arterial blood pressure in the tilted position during central sympathetic blockade.     

Spectral analysis of internally leaking shut-down valves

We herein describe the results obtained from a set of experiments conducted on a shut-down valve, the objective of which was to identify the degree of internal leakage through the valve in its closed state. Leakage in a valve is not only a concern in terms of safety, but can also contribute to high maintenance costs and the loss of supply. Any improvements to the methods available for monitoring the condition to the valve may yield substantial cost savings and safer working conditions. All the experiments were conducted after causing damage to a valve and by subsequent monitoring of the vibrations caused by the resulting leak, using different types of instrumentation, including acoustic emission and dynamic pressure sensors. We carried out an analysis of the data obtained, in which our primary focus was the spectrum of frequencies obtained from each of the signals emitted. The methods we used deemed to be effective for the detection of leaks. The quantification of the leaks is a rather more complex matter that warrants further investigation, however. Further research is also suggested on the effect of external disturbances, the influence of the experimental parameters, and the applicability of analytical models.     

Inactivation of pathogens on pork by steam-ultrasound treatment

The objective of the study was to evaluate a new pathogen inactivation concept that combines application of pressurized steam simultaneously with high-power ultrasound through a series of nozzles. On skin and meat surfaces of pork jowl samples, counts of total viable bacteria were reduced by 1.1 log CFU/cm(2) after treatment for 1 s and by 3.3 log CFU/cm(2) after treatment for 4 s. The mean reduction of 1.7 to 3.3 log CFU/cm(2) on the skin surface was significantly higher than the reduction of 1.1 to 2.5 log CFU/cm(2) on the meat surface. The inactivation of Salmonella Typhimurium, Salmonella Derby, Salmonella Infantis, Yersinia enterocolitica, and a nonpathogenic Escherichia coli was studied on inoculated samples that were treated for 0.5 to 2.0 s. With one exception, no significant differences in reduction were observed among the bacterial types. After treatment for 0.5 s, the 0.9-to 1.5-log reductions of E. coli were significantly higher than the 0.4- to 1.1-log reductions for Salmonella and Y. enterocolitica. Overall, reductions increased by increasing treatment time; reductions were 0.4 to 1.5 log CFU/cm(2) after treatment for 0.5 s and 2.0 to 3.6 log CFU/cm(2) after treatment for 2 s. Reductions on the skin (1 to 3.6 log CFU/cm(2)) were significantly higher than reductions on the meat surface (1 to 2.5 log CFU/cm(2)). The reduced effect on the meat surface may be explained by greater protection of bacteria in deep structures at the muscle surface. No significant difference in reduction was observed between samples inoculated with 10(4) CFU/cm(2) and those inoculated with 10(7) CFU/cm(2), and cold storage of samples for 24 h at 5°C after steam-ultrasound treatment did not lead to changes in recovery of bacteria.     

Modeling thermal management of lithium-ion PNGV batteries

Batteries were designed with the aid of a computer modeling program to study the requirements of the thermal control system for meeting the goals set by the Partnership for a New Generation of Vehicles (PNGV). The battery designs were based upon the lithium-ion cell composition designated Gen-2 in the US Department of Energy Advanced Technology Development Program. The worst-case cooling requirement that would occur during prolonged aggressive driving was estimated to be 250 W or about 5 W per cell for a 48-cell battery. Rapid heating of the battery from a very low startup temperature is more difficult than cooling during driving. A dielectric transformer fluid is superior to air for both heating and cooling the battery. A dedicated refrigeration system for cooling the battery coolant would be helpful in maintaining low temperature during driving. The use of ample insulation would effectively slow the battery temperature rise when parking the vehicle in warm weather. Operating the battery at 10 °C during the first several years when the battery has excess power would extend the battery life.     

Fish Oil Supplementation During Late Pregnancy Does Not Influence Plasma Lipids or Lipoprotein Levels in Young Adult Offspring

Nutritional influences on cardiovascular disease operate throughout life. Studies in both experimental animals and humans have suggested that changes in the peri- and early post-natal nutrition can affect the development of the various components of the metabolic syndrome in adult life. This has lead to the hypothesis that n-3 fatty acid supplementation in pregnancy may have a beneficial effect on lipid profile in the offspring. The aim of the present study was to investigate the effect of supplementation with n-3 fatty acids during the third trimester of pregnancy on lipids and lipoproteins in the 19-year-old offspring. The study was based on the follow-up of a randomized controlled trial from 1990 where 533 pregnant women were randomized to fish oil (n = 266), olive oil (n = 136) or no oil (n = 131). In 2009, the offspring were invited to a physical examination including blood sampling. A total of 243 of the offspring participated. Lipid values did not differ between the fish oil and olive oil groups. The relative adjusted difference (95% confidence intervals) in lipid concentrations was −3% (−11; 7) for LDL cholesterol, 3% (−3; 10) for HDL cholesterol, −1% (−6; 5) for total cholesterol,−4% (−16; 10) for TAG concentrations, 2%(−2; 7) for apolipoprotein A1, −1% (−9; 7) for apolipoprotein B and 3% (−7; 15) in relative abundance of small dense LDL. In conclusion, there was no effect of fish oil supplementation during the third trimester of pregnancy on offspring plasma lipids and lipoproteins in adolescence.     

Digital hardware implementation of a current controller for IMvariable-speed drives

This paper presents the design of an induction machine current controller that is entirely implemented in digital hardware. A hardware current controller allows high switching frequencies with only modest processing power, as well as simplified controller hardware and software. The paper briefly presents the concepts of the algorithm implemented, and then outlines the changes that are made to make the digital implementation even more efficient. It then discusses the architecture used for the hardware design. Experimental results are presented to demonstrate the algorithm's performance     

Structural interactions between horseradish peroxidase C and the substrate benzhydroxamic acid determined by X-ray crystallography

The three-dimensional structure of recombinant horseradish peroxidase in complex with BHA (benzhydroxamic acid) is the first structure of a peroxidase-substrate complex demonstrating the existence of an aromatic binding pocket. The crystal structure of the peroxidase-substrate complex has been determined to 2.0 A resolution with a crystallographic R-factor of 0.176 (R-free = 0. 192). A well-defined electron density for BHA is observed in the peroxidase active site, with a hydrophobic pocket surrounding the aromatic ring of the substrate. The hydrophobic pocket is provided by residues H42, F68, G69, A140, P141, and F179 and heme C18, C18-methyl, and C20, with the shortest distance (3.7 A) found between heme C18-methyl and BHA C63. Very little structural rearrangement is seen in the heme crevice in response to substrate binding. F68 moves to form a lid on the hydrophobic pocket, and the distal water molecule moves 0.6 A toward the heme iron. The bound BHA molecule forms an extensive hydrogen bonding network with H42, R38, P139, and the distal water molecule 2.6 A above the heme iron. This remarkably good match in hydrogen bond requirements between the catalytic residues of HRPC and BHA makes the extended interaction between BHA and the distal heme crevice of HRPC possible. Indeed, the ability of BHA to bind to peroxidases, which lack a peripheral hydrophobic pocket, suggests that BHA is a general counterpart for the conserved hydrogen bond donors and acceptors of the distal catalytic site. The closest aromatic residue to BHA is F179, which we predict provides an important hydrophobic interaction with more typical peroxidase substrates.     

Ground effects on induced voltages from nearby lightning

The lightning induced voltage on overhead lines from return strokes and it's dependency of a lossy ground is analyzed using a new, analytical vector potential formulation. Norton's (1937) approximation and the surface impedance approach are used to take loss effects into account. The surface impedance method predicts in general induced voltages in good agreement with Norton's approximation, but the accuracy of the method is dependent on the variation of the current along the lightning channel. Norton's method is compared with the exact Sommerfeld solution, showing a deviation <10% even for low conducting grounds and distances from 100-1000 m. The effect of stroke location and line termination is also analyzed, showing that a line terminated by it's characteristic impedance and excited by a return stroke at the prolongation of the line is especially sensitive to lossy ground effects. Strokes near the mid-point of an overhead line gives less loss effect than strokes at the end of the line. The surface impedance approximation is derived from Norton's method and the necessary assumptions are outlined