On estimating the interface normal and curvature in piecewise linear interface calculation-volume of fluid approach for three-dimensional arbitrary meshes

Volume of fluid (VOF) method with its Piecewise Linear Interface Calculation (PLIC) reconstruction algorithm is one of the most popular approaches in numerical simulation of interfacial flows with a wide range of applications in different areas. In an effort to evaluate the similarity of the PLIC-generated planes in comparison with the exact interface, a point-cloud, based on the polygon centers of PLIC planes is extracted, which later is used to form a triangular grid that represents the estimated interface. The main objective of this article is to evaluate the interface geometrical properties based on the extracted triangular grid of the interface. The methods presented in this article, characterized by a higher spatially convergence ratio, are compared with the commonly used methods. The proposed methods are tested for two 3-dimensional general test cases, where an evident improvement is seen in calculation accuracy and spatial convergence of the errors of interface normal vector and curvature.     

Bayesian prior probability distributions for internal dosimetry

The problem of choosing a prior distribution for the Bayesian interpretation of measurements (specifically internal dosimetry measurements) is considered using a theoretical analysis and by examining historical tritium and plutonium urine bioassay data from Los Alamos. Two models for the prior probability distribution are proposed: (1) the log-normal distribution, when there is some additional information to determine the scale of the true result, and (2) the 'alpha' distribution (a simplified variant of the gamma distribution) when there is not. These models have been incorporated into version 3 of the Bayesian internal dosimetry code in use at Los Alamos (downloadable from our web site). Plutonium internal dosimetry at Los Alamos is now being done using prior probability distribution parameters determined self-consistently from population averages of Los Alamos data.     

Synthesis and pharmacological evaluation of 1-methyl-5-[substituted-4 (3H)-oxo-1,2,3-benzotriazin-3-yl]-1H-pyrazole-4-acetic acid derivatives

Several new 1-methyl-5-[substituted-4-oxo-1,2,3-benzotriazin-3-yl] -1H-pyrazole-4-acetic acids and their ethyl ester derivatives were prepared. The compounds were tested for analgesic and antiinflammatory activities, acute toxicity, ulcerogenic effect, and as in vitro inhibitors of 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD), since it is claimed that the inhibition of such an enzyme predicts in vivo antiinflammatory activity. Some compounds were more active than phenylbutazone in the phenylbenzoquinone and acetic acid peritonitis tests, and equiactive to the same drug in the carrageenin paw edema test. All the compounds inhibited the 3 alpha-HSD, but no correlation was observed with the paw edema inhibition values. The compounds proved to possess marginal or no ulcerogenic effect, as well as low systemic toxicity.     

Adverse prognostic value of a blunted circadian rhythm of heart rate in essential hypertension

BACKGROUND: Previous studies revealed a direct association between resting heart rate and risk of mortality in essential hypertension. However, resting heart rate is a highly variable measure since it is affected by the alerting reaction to the visit. OBJECTIVE: To investigate whether the heart rate values recorded during the 24 h of ambulatory blood pressure monitoring are independent predictors of survival of uncomplicated subjects with essential hypertension. METHODS: We followed up 1942 initially untreated and uncomplicated subjects with essential hypertension (mean age 51.7 years, 52% men) for an average of 3.6 years (range 0-10 years). All subjects underwent baseline procedures including 24 h non-invasive blood pressure monitoring with simultaneous assessment of heart rate, one reading every 15 min for 24 h. MAIN OUTCOME MEASURES: All-cause mortality and cardiovascular morbidity. RESULTS: During follow-up there were 74 deaths from all causes (1.06 per 100 person-years) and 182 total (fatal plus non-fatal) cardiovascular morbid events (2.66 per 100 person-years). Clinic, average 24 h, daytime and night-time heart rates exhibited no association with total mortality. However, the subjects who subsequently died had had a blunted reduction of heart rate on going from day to night during the baseline examination. After adjustment for age (P < 0.001), diabetes (P < 0.001) and average 24 h systolic blood pressure (SBP, P= 0.002) in a Cox model, for each 10% less reduction in the heart rate from day to night the relative risk of mortality was 1.30 (95% confidence interval 1.02-1.65, P = 0.04). Rates of death were 0.38, 0.71, 0.94 and 2.0 per 100 person-years among subjects in the four quartiles of the distribution of the percentage reduction in heart rate from day to night The baseline day-night changes in the heart rate exhibited an inverse correlation to age and to clinic and ambulatory SBP and a direct association with the day-night changes in blood pressure. The degree of reduction of heart rate from day to night also had an independent inverse association with total cardiovascular morbidity after adjustment for age, diabetes and left ventricular hypertrophy, but this association did not remain significant when average 24 h SBP and the degree of day-night reduction in SBP were entered into the equation. CONCLUSIONS: A flattened diurnal rhythm of heart rate in uncomplicated subjects with essential hypertension is a marker of risk for subsequent all-cause mortality and this association persists after adjustment for several risk factors. For assessing these subjects, a limited and uniformly distributed period of ambulatory heart rate recording during the 24 h is clinically valuable.     

Ambulatory pulse pressure: a potent predictor of total cardiovascular risk in hypertension

A wide pulse pressure (PP) is a marker of increased artery stiffness and high cardiovascular (CV) risk. To investigate the prognostic value of ambulatory PP, which is currently unknown, we studied 2010 initially untreated subjects with uncomplicated essential hypertension (mean age, 51.7 years; 52% men). All subjects underwent baseline procedures including 24-hour noninvasive ambulatory blood pressure (BP) monitoring. The mean duration of follow-up was 3.8 years (range, 0 to 11 years), and CV morbidity and mortality were the outcome measures. There were 200 major CV events (2.61 per 100 person-years), 36 of which were fatal (0.47 per 100 person-years). In the 3 tertiles of the distribution of office PP, the rate of total CV events (per 100 persons per year) was 1.38, 2. 12, and 4.34, respectively, and that of fatal events was 0.12, 0.30, and 1.07 (log-rank test, both P<0.01). In the 3 tertiles of the distribution of average 24-hour PP, the rate of total CV events was 1.19, 1.81, and 4.92, and that of fatal events was 0.11, 0.17, and 1. 23 (log-rank test, both P<0.01). After controlling for several independent risk markers including white coat hypertension and nondipper status, we found that ambulatory PP was associated with the biggest reduction in the -2 log likelihood statistics for CV morbidity (P<0.05 versus office PP). In each of the 3 tertiles of office PP, CV morbidity and mortality increased from the first to the third tertile of average 24-hour ambulatory PP (log-rank test, all P<0.01). Age, left ventricular hypertrophy, and nondipper status were independent predictors of CV mortality, and the further predictive effect of ambulatory PP (P<0.001) was marginally but not significantly superior to that of office PP and average 24-hour systolic BP. We conclude that ambulatory PP is a potent risk marker in essential hypertension. CV morbidity is more closely predicted by ambulatory than by office PP even after control for multiple risk factors.     

Clinical and laboratory findings concerning at first dietary and afterwards cimetidine treatment of acute intermittent porphyria

Clinical symptoms and laboratory findings were assessed in three women with acute intermittent porphyria. After 15 days of pharmacologic washout and free diet (time 0), the patients were give a well balanced normocaloric diet for 7 days (time 1), followed by 7 days of high carbohydrate normocaloric diet (time 2); on days 15 to 21 (time 3) well balanced normocaloric diet was given, and finally on days 22 to 28 (time 4) to the well balanced normocaloric diet cimetidine (0.4 g twice daily) was added. On days 3, 5, and 7 of times 1-4 the following porphyrin precursors were determined: ALA, PBG, total uroporphyrin, total coproporphyrin, and total porphyrin. At times 1 and 3, high values were found while levels dropped to normal during times 2 and 4. During times 1 and 3, patients complained of headache, insomnia and anxiety; during time 2, all patients complained of anxiety and only one suffered from insomnia. Finally, during time 4, all patients had only slight anxiety. Untoward effects of cimetidine were not observed in any of the patients.     

A 3-V 5.4-mW BiCMOS track & hold circuit with samplingfrequency up to 150 MHz

A track & hold circuit to be used in front of a high-speed analog-to-digital converter (ADC) is proposed. In order to achieve the required resolution with a single 3-V supply, a fully differential closed-loop architecture is used. The track & hold circuit processes a differential 1-Vpp output signal swing and achieves more than 8-b linearity with sampling frequency up to 150 MHz. In these conditions, the total power consumption is 5.4 mW from a single 3-V supply. The circuit has been realized in a 0.7 μm BiCMOS technology, and its active area is about 0.15 mm²