Memorial University of Newfoundland

About: Memorial University of Newfoundland is a education organization based out in St. John's, Newfoundland and Labrador, Canada. It is known for research contribution in the topics: Population & Gadus. The organization has 13818 authors who have published 27785 publications receiving 743594 citations. The organization is also known as: Memorial University & Memorial University of Newfoundland and Labrador.

Theory and simulation of the generation of whistler-mode chorus

Abstract: [1] The generation process of whistler-mode chorus emissions is analyzed by both theory and simulation. Driven by an assumed strong temperature anisotropy of energetic electrons, the initial wave growth of chorus is linear. After the linear growth phase, the wave amplitude grows nonlinearly. It is found that the seeds of chorus emissions with rising frequency are generated near the magnetic equator as a result of a nonlinear growth mechanism that depends on the wave amplitude. We derive the relativistic second-order resonance condition for a whistler-mode wave with a varying frequency. Wave trapping of resonant electrons near the equator results in the formation of an electromagnetic electron hole in the wave phase space. For a specific wave phase variation, corresponding to a rising frequency, the electron hole can form a resonant current that causes growth of a wave with a rising frequency. Seeds of chorus elements grow from the saturation level of the whistler-mode instability at the equator and then propagate away from the equator. In the frame of reference moving with the group velocity, the wave frequency is constant. The wave amplitude is amplified by the nonlinear resonant current, which is sustained by the increasing inhomogeneity of the dipole magnetic field over some distance from the equator. Chorus elements are generated successively at the equator so long as a sufficient flux of energetic electrons with a strong temperature anisotropy is present.

The prognostic importance of left ventricular geometry in uremic cardiomyopathy.

Abstract: The objective of this study was to determine the effect of left ventricular (LV) mass, volume, and mass-to-volume ratio on mortality in chronic dialysis patients. The Design was a multicenter, prospective inception cohort study with a median follow-up of 41 months. The Setting was three university-affiliated nephrology units. A total of 433 patients who (1) survived > 6 months from the start of ESRD therapy and (2) had a technically satisfactory baseline echocardiogram were studied. Measurements included a baseline clinical, laboratory and echocardiographic assessment. LV hypertrophy was present in 74% and LV dilation was present in 36% of patients. In patients with normal cavity volume ( 120 g/m2) and mass-to-volume ratios (> 2.2 g/mL) were independently associated with late mortality (> 2 yr after starting dialysis therapy). After adjusting for baseline age, diabetes, and ischemic heart disease, the relative risk for the former was 3.29 and for the latter was 2.24. Cavity volume was of no prognostic significance in this group. In patients with LV dilation and normal systolic function, high cavity volume (> 120 mL/m2) and low mass-to-volume ratio (< 1.8 mL/m2) were independently associated with late mortality, the relative risk in the former being 17.14 and the latter being 4.27. LV mass index was of no prognostic significance in this group. The baseline echocardiographic classification, based on LV mass and cavity volume, was the strongest predictor of late mortality, after adjusting for age, gender, diabetes mellitus, coronary artery disease, angina pectoris, chronic hypertension, and hemoglobin and serum albumin levels.(ABSTRACT TRUNCATED AT 250 WORDS)

VLDL, apolipoproteins B, CIII, and E, and risk of recurrent coronary events in the cholesterol and recurrent events (CARE) trial

Abstract: Background—Plasma triglyceride concentration has been an inconsistent independent risk factor for coronary heart disease, perhaps because of the metabolic heterogeneity among VLDL particles, the main carriers of triglycerides in plasma. Methods and Results—We conducted a prospective, nested case-control study in the Cholesterol and Recurrent Events (CARE) trial, a randomized placebo-controlled trial of pravastatin in 4159 patients with myocardial infarction and average LDL concentrations at baseline (115 to 174 mg/dL, mean 139 mg/dL). Baseline concentrations of VLDL–apolipoprotein (apo) B (the VLDL particle concentration), VLDL lipids, and apoCIII and apoE in VLDL+LDL and in HDL were compared in patients who had either a myocardial infarction or coronary death (cases, n=418) with those in patients who did not have a cardiovascular event (control subjects, n=370) in 5 years of follow-up. VLDL-cholesterol, VLDL-triglyceride, VLDL-apoB, apoCIII and apoE in VLDL+LDL and apoE in HDL were all interrelated, and ...

Antifreeze proteins of teleost fishes.

Abstract: ▪ Abstract Marine teleosts at high latitudes can encounter ice-laden seawater that is approximately 1°C colder than the colligative freezing point of their body fluids. They avoid freezing by produ...

Isolation and characterization of antioxidative peptides from gelatin hydrolysate of Alaska pollack skin.

Abstract: Gelatin extracted from Alaska pollack skin was hydrolyzed with serial digestions in the order of Alcalase, Pronase E, and collagenase using a three-step recycling membrane reactor. The fraction from the second step, which was hydrolyzed with Pronase E, was composed of peptides ranging from 1.5 to 4.5 kDa and showed high antioxidative activity. Two different peptides showing strong antioxidative activity were isolated from the hydrolysate using consecutive chromatographic methods including gel filtration on a Sephadex G-25 column, ion-exchange chromatography on a SP-Sephadex C-25 column, and high-performance liquid chromatography on an ODS column. The isolated peptides, P1 and P2, were composed of 13 and 16 amino acid residues, respectively; and both peptides contained a Gly residue at the C-terminus and the repeating motif Gly-Pro-Hyp. The antioxidative activities of the purified peptides were measured using the thiobarbituric acid method, and the cell viability was measured with MTT assay. The results showed that P2 had potent antioxidative activity on peroxidation of linoleic acid. Moreover, the cell viability of cultured liver cells was significantly enhanced by addition of the peptide. These results indicate that the purified peptide, P2, from gelatin hydrolysate of Alaska pollack skin is a natural antioxidant which has potent antioxidative activity.