Differential responses in anterior pituitary luteinizing hormone (LH) content and LH beta- and alpha-subunit mRNA, and plasma concentrations of LH and testosterone, in bulls treated with the LH-releasing hormone agonist deslorelin

Tooth loss diminishes oral function and quality of life, and national health targets aim to reduce population levels of tooth loss. OBJECTIVES: The purpose of this study was to determine tooth loss incidence and predictors of tooth loss among older adults in South Australia. METHODS: Data were obtained from a cohort study of a stratified random sample of community-dwelling dentate people aged 60+ years. Interviews and oral examinations were conducted among 911 individuals at baseline and among 693 of them (76.1%) 2 years later. Incidence rates and relative risks were calculated for population subgroups and multivariate logistic regression was used to construct risk prediction models. A method was developed to calculate 95% confidence intervals (95% CI) for relative risks (RR) from logistic regression models using a Taylor series approximation. RESULTS: Some 19.5% (95% CI = 15.4-23.6%) of people lost one or more teeth during the 2 years. Men, people with a recent extraction, people who brushed their teeth infrequently, smokers and people born outside Australia had significantly (P < 0.05) greater risk of tooth loss. Baseline clinical predictors of tooth loss included more missing teeth, retained roots, decayed root surfaces, periodontal pockets and periodontal recession. In a multivariate model that controlled for baseline clinical predictors, former smokers (RR = 2.55, 95% CI = 1.48-4.40) and current smokers (RR = 2.06, 95% CI = 0.92-4.62) had similarly elevated risks of tooth loss compared with non-smokers. CONCLUSIONS: The findings from this population suggest that a history of smoking contributes to tooth loss through mechanisms in addition to clinical disease processes alone.     

Parallelisation of storage cell flood models using OpenMP

This paper describes the implementation and benchmarking of a parallel version of the LISFLOOD-FP hydraulic model based on the OpenMP Application Programming Interface. The motivation behind the study was that reducing model run time through parallelisation would increase the utility of such models by expanding the domains over which they can be practically implemented, allowing previously inaccessible scientific questions to be addressed. Parallel speedup was calculated for 13 models distributed over seven study sites and implemented on one, two, four and in selected cases eight processor cores. The models represent a range of previous applications from large area, coarse resolution models of the Amazon, to fine resolution models of urban areas, to orders of magnitude smaller models of rural floodplains. Parallel speedups were greater for larger model domains, especially for models with over 0.2–0.4 million cells where parallel efficiencies of up to 0.75 on four and eight cores were achieved. A key advantage of using OpenMP and an explicit rather than implicit model was the ease of implementation and minimal code changes required to run simulations in parallel.     

Work Function Tunability of Refractory Metal Nitrides by Lanthanum or Aluminum Doping for Advanced CMOS Devices

A lanthanum (La)-doped HfN is investigated as an n-type metal gate electrode on SiO₂ with tunable work function. The variation of La concentration in (HfinfinLa_1-x)N_y modulates the gate work function from 4.6 to 3.9 eV and remains stable after high-temperature annealing (900degC to 1000degC), which makes it suitable for n-channel MOSFET application. An ultrathin high-fc dielectric layer was formed at the metal/SiO₂ interface due to the (HfinfinLa_1-x)N_y and SiO₂ interaction during annealing. This causes a slight reduction in the effective oxide thickness and improves the tunneling current of the gate dielectric by two to three orders. We also report the tunability of TaN with Al doping, which is suitable for a p-type metal gate work function. Based on our results, several dual-gate integration processes by incorporating lanthanum or aluminum into a refractory metal nitride for CMOS technology are proposed.     

Characterizing the spectral-temporal response of burned savannah using in situ spectroradiometry and infrared thermometry

The spectral evolution of a savannah site in north-east Namibia was recorded in situ     

Pressure equalization in diffusion cells

Design of a pressure equalization device is described that imposes a fixed pressure to minimize the relative importance of pressure fluctuations in steady state, counterdiffusion measurements employing a Wicke–Kallenbach diffusion cell. The success of this design is shown in observing gas diffusion in a liquid-filled, porous, sintered–steel plate.     

Indications for the surgical repair of unilateral aural atresia in children

OBJECTIVE: This study aimed to clarify the indications for elective surgical repair of unilateral aural atresia in children and to review the rates of successful repair in the literature. DATA SOURCES: A search of the published English language literature, 1966-1997, was conducted using the key words aural atresia. STUDY SELECTION: Articles were selected on the basis of their inclusion of the authors' indications for surgical repair of aural atresia or the inclusion of surgical series that showed outcomes. DATA EXTRACTION: Articles reviewed in the review had to either provide specific guidelines for surgical repair of unilateral aural atresia or provide postoperative pure-tone averages, air-bone gaps, or speech reception thresholds. DATA SYNTHESIS: The authors compiled the relevant data into summary tables and extracted conclusions from these data. CONCLUSIONS: Elective surgical repair of unilateral aural atresia should only be attempted in children who meet specific anatomic criteria that predict that they are the most likely to benefit from the results of surgery. Otherwise, repair should be delayed until the age at which the patient can make an informed decision, knowing the risks, benefits, and consequences of this difficult surgery. Parents and surgeons must have a realistic expectation of the surgical results and the practiced benefit to be expected with a normal, contralateral ear.     

Survival after relapse in childhood acute lymphoblastic leukemia: impact of site and time to first relapse--the Children''s Cancer Group Experience

After cardioversion from atrial fibrillation (AF) many patients develop early recurrence of the arrhythmia. While these patients may be appropriate for immediate prophylaxis against AF recurrence their identification at the time of cardioversion is not possible. Since the signal-averaged P wave (SAPW) is abnormal in individuals with atrial arrhythmia, we assessed its utility for predicting early AF recurrence after cardioversion. Seventy-five cardioversions in 31 patients were evaluated. The mean age was 59 (range 28-79) years; 26 were male. Fifty-eight cardioversions were internal using low energy biphasic DC shocks delivered via electrodes placed in the right atrial appendage and coronary sinus. P wave specific signal averaging was performed at 3 and 24 hours after each cardioversion to estimate filtered P wave duration and energy from 20, 40, and 60 to 150 Hz. Follow-up was by regular clinic visits and transtelephonic ECG monitoring. Early recurrence of AF (prospectively defined as sinus rhythm duration < 1 week) occurred after 30 cardioversions. No differences were found in any P wave variable measured at 3 hours between these cardioversions and those that resulted in a longer duration of sinus rhythm. Paired 3- and 24-hour signal-averaged data were available in 47 cardioversions. There were significant falls in P wave energy from 3 to 24 hours after 31 cardioversions that resulted in sinus rhythm for > 1 week, (P40: 3 hours 11.2 [+/- 1.5] micro V2.s, 24 hours 8.6 [+/- 1.2] micro V2.s, P < 0.001), but not following the 16 after which AF returned within 1 week (P40: 3 hours 9.0 [+/- 1.2] micro V2.s, 24 hours 8.5 [+/- 1.2 micro V2.s, P = NS). A fall in P40 of > 25% had a positive predictive accuracy for maintenance of sinus rhythm of 87%; negative predictive accuracy was only 37%. Similar falls in P wave energy occurred after cardioversions that resulted in longer term (> 4 weeks) sinus rhythm, but not in those that did not. However, the predictive accuracy of a fall in P40 was less (positive predictive accuracy 38%, negative predictive accuracy 62%). Patients with relapsing permanent AF who remain in sinus rhythm for at least 1 week after cardioversion show a fall in P wave energy within the first 24 hours. However, in these patients the technique does not predict recurrent AF within 1 week nor sinus rhythm > 4 weeks. These observations suggest persistent disordered atrial activation as a mechanism for early recurrence of AF after cardioversion.     

The fabrication of O′-sialon ceramics by pressureless sintering

Low-porosity ceramics with O′-sialon as the major crystalline phase have been successfully fabricated by pressureless sintering. Densification at 1400 to 1800° C is interpreted using Kingery's liquid-phase sintering model. Particle rearrangement accounts for a significant proportion of the overall densification and is closely related to the amount and viscosity of the liquid present. The oxidation resistance of fabricated samples is good but, at temperatures above 1300° C, decreases with increasing alumina content in the starting mix. Modulus of rupture values of about 420 MPa at room temperature are high enough to encourage further work.     

An examination of the reactive sputtering of silicon nitride on to gallium arsenide

The deposition of silicon nitride thin films by the reactive sputtering of elemental silicon in a nitrogen/argon plasma has been investigated. The composition of the thin films has been examined using infra-red reflectance, X-ray photoelectron and Auger electron spectroscopies and spark source mass spectrometry. Oxygen has been found to be a major contaminant in these sputter deposited films, the oxygen concentration depending on the ambient gas pressure. The use of the silicon oxy-nitride films as annealing encapsulants for the activation of silicon ion implanted semi-insulating gallium arsenide has also been investigated.