Intestinal passage of microencapsulated fish oil in rats following oral administration

Fish oil labelled with [(14)C-linolenin] tracer was orally administered by gavage as an oil-water mixture (free oil) or as an oil-in-water emulsion formulation (microencapsulated oil) to fasted rats. Groups of rats were then given food after gavage or alternatively not fed to examine the effect of food on intestinal passage. Feeding after gavage drives lumenal free oil faster through the gastrointestinal (GI) tract. Microencapsulation slows down the lumenal progression in the GI tract with feeding. Non-feeding also slows down the lumenal progress of free oil in the GI tract but this is not influenced by microencapsulation. Analysis of the relative distribution of the label along the GI tract tissue wall showed that the upper small intestine was the main site of label accumulation in the GI tract. Of the oil that remained in the lumen, there was slight protection against early uptake and metabolism in the stomach and upper GI tract in rats that were either fed or not fed after dosing when microencapsulated oil was administered. Microencapsulation increased the levels of radiolabel in the liver and blood. The primary organ for accumulation of radiolabel for both free and microencapsulated oils in rats that were fed or fasted after dosing was the liver.     

The effects of sediment size fraction and associated algal biofilms on the kinetics of phosphorus release

Experiments using flumes containing sediment of three different size fractions, from two sites on the River Tame, investigated the influences of sediment particle size, and an associated biofilm, on sediment-water exchanges in heterogeneous sediment deposits. This is the first study undertaken to understand the kinetics of the release of soluble reactive phosphorus from sediments of natural systems to identify which of the size compartments affected those fluxes most. Samples of fine material (<2 mm), gravel (2-20 mm), and stones (>20 mm) were collected over a period of several weeks and brought to a fluvarium where they were placed in artificial, controlled flow, and flume channels. Synthetic solutions of similar ionic strength to the river were prepared using calcium chloride. Temperature, pH, and dissolved oxygen of the solution overlying the sediment were monitored automatically whilst filtered samples were obtained at 2 h intervals over 48 h. The biomass, expressed as mg m(-2) chlorophyll a, of the algal component of the biofilm from the surface of the sediment was estimated using methanol extraction. Differences in the responses were observed between the sediment size fractions and the two sites, where contaminant concentrations varied. The equilibrium phosphate concentration and a phosphorus transfer index were used to establish that there was a net uptake of phosphorus by all three sediment size fractions, from both sites, at the time of sampling. The kinetic results showed very fast initial reactions of phosphorus release from the larger size fractions with a well-developed filamentous algal growth present implying a different mechanism than diffusion being involved. The stones and associated biofilms also released more phosphorus than the fine fraction, e.g. final release concentrations for the most contaminated site were: fines approximately 2.5 microM, gravel approximately 6.5 microM, and stones approximately 65.0 microM (expressed as soluble reactive phosphorus). Phosphorus fluxes, calculated assuming the concentration of phosphorus in the sediment was less than the equilibrium concentration, were a maximum at the most contaminated site, e.g. fines 6.4 nmol m(-2) s(-1), gravel 27 nmol m(-2) s(-1), and stones 109 nmol m(-2) s(-1) (normalised with respect to the river bed area). These results confirm that sediment having a biofilm and associated particulate material results in a greater flux than fine sediment, which does not support a filamentous biomass. Removal of the fine particulates trapped in the algal growth reduced soluble phosphorus release. These factors demonstrate that both gravel and stone substrates have an important control over the release of soluble reactive phosphorus.     

Effects of intravenous magnesium sulfate on arrhythmias in patients with congestive heart failure

Intravenous magnesium is an effective treatment for ventricular tachycardia of some etiologies, and in patients with congestive heart failure low serum magnesium concentrations are associated with frequent arrhythmias and high mortality. This suggests that magnesium administration may decrease the frequency of ventricular arrhythmias in patients with heart failure. We therefore assessed the impact of an intravenous magnesium infusion upon the frequency of ventricular premature depolarizations in 40 patients with New York Heart Association (NYHA) class II to IV heart failure and serum magnesium < or = 2.0 mg/dl. Within 1 week of a baseline 6-hour ambulatory electrocardiographic recording, an infusion of 0.2 mEq/kg of MgSO4 was given over 1 hour and a repeat 6-hour recording was obtained. There was an inverse relationship between the change in magnesium concentration and the change in frequency of premature ventricular depolarizations; premature ventricular depolarizations declined by 134 +/- 207 hr-1 in patients in whom serum magnesium concentration increased > or = 0.75 mg/dl, but increased by 72 +/- 393 hr-1 in patients with a change < 0.75 mg/dl (p < 0.05). For all patients, the frequency of premature ventricular depolarizations was 283 +/- 340 hr-1 pretreatment and 220 +/- 269 hr-1 following magnesium infusion (p = 0.21). Patients with > or = 300 premature ventricular depolarizations hr-1 demonstrated a decrease from 794 +/- 309 to 369 +/- 223 hr-1 (p < 0.001). Intravenous magnesium administration decreased the frequency of couplets from 233 +/- 505 to 84 +/- 140 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Prospective evaluation of three smoking interventions in 205 recovering alcoholics: One-year results of Project SCRAP-Tobacco.

205 (113 male, 92 female) nonhospitalized recovering alcoholics with >3 mo of continuous abstinence from alcohol and drugs and relatively heavy tobacco dependence (Fagerstrom Tolerance Questionnaire score?=? 7.7; mean number of cigarettes per day, 26.8; mean number of years smoked, 24.4) were randomized to standard treatment (ST) American Lung Association quit program plus nicotine anonymous meetings (n?=?70), behavioral counseling plus physical exercise (BEX; n?=?72), or behavioral counseling plus nicotine gum (BNIC; n?=?63). A 3?×?4 repeated measures design was used to evaluate the effectiveness of the interventions on smoking outcome at baseline, posttreatment, and 6- and 12-mo follow-ups. Self-reported smoking status was verified with biochemical and informant report. Verified self-report indicated that significantly more smokers in BEX quit by posttreatment (60%) than in either BNIC (52%) or ST (31%), χ–2(2, N?=?205)?=?17.85, p?     

Mechanical behavior of segmented oxide protective coatings

Mechanically and thermally induced fractures were examined in sputtered coatings consisting of an NiCrAlY underlayer, either a thin or a thick transition layer grading from NiCrAlY to ZrO₂, and an outer ZrO₂ layer. A pronounced columnar (fibrous) microstructure was obtained, although the columnar boundaries in the ZrO₂ layers and in the thick transition layers were much more open than in the NiCrAlY, effectively producing a more segmented structure. Some coatings also included a continuous fine-grained outer NiCrAlY sealing or close-out layer.For this complex metal and ceramic coating, a stress applied parallel to the layer plane always resulted in fracture perpendicular to the layer plane along open columnar boundaries. If the transition layer was thick, no fractures other than those at columnar boundaries were observed. If the transition layer was thin, fracture parallel to the layer plane occured in the ZrO₂-rich portion of this layer. When stress was perpendicular to the layer plane, fracture parallel to the layer plane occurred first at the outer ZrO₂(NiCrAlY) interface if an outer NiCrAlY sealing layer was present. Otherwise the ZrO₂-rich portion of the transition layer failed first, followed by fracture in the ZrO₂ layer.     

A minimum time seek controller for a disk drive

A time optimal controller design is proposed for the purpose of steering the read/write head of a magnetic disk drive during a seek manuever. The design includes the development of a switch-on-time (SOT) open loop slew control using a third order model of the voice coil motor. The SOT algorithm employs a look up table of switch times versus angle. A perturbation correction stage is included to tailor the switch times to adjust for variations in the operating characteristic of the disk drive (due, for example to heat buildup, wear, etc.). The design also includes a terminal stage servo control that employs an optimal feedback/feedforward controller which is used to provide precise positioning at the end of the seek maneuver     

LWIR HgCdTe Detectors Grown on Ge Substrates

Long-wavelength infrared (LWIR) HgCdTe p-on-n double-layer heterojunctions (DLHJs) for infrared detector applications have been grown on 100 mm Ge (112) substrates by molecular beam epitaxy (MBE). The objective of this current work was to grow our baseline p-on-n DLHJ detector structure (used earlier on Si substrates) on 100 mm Ge substrates in the 10 μm to 11 μm LWIR spectral region, evaluate the material properties, and obtain some preliminary detector performance data. Material characterization techniques included are X-ray rocking curves, etch pit density (EPD) measurements, compositional uniformity determined from Fourier-transform infrared (FTIR) transmission, and doping concentrations determined from secondary-ion mass spectroscopy (SIMS). Detector properties include resistance-area product (RoA), spectral response, and quantum efficiency. Results of LWIR HgCdTe detectors and test structure arrays (TSA) fabricated on both Ge and silicon (Si) substrates are presented and compared. Material properties demonstrated include X-ray full-width of half-maximum (FWHM) as low as 77 arcsec, typical etch pit densities in mid 10⁶ cm⁻² and wavelength cutoff maximum/minimum variation <2% across the full wafer. Detector characteristics were found to be nearly identical for HgCdTe grown on either Ge or Si substrates.