Uncertainty in multiple penetration depth fringing electric field sensor measurements

Measurement of multilayer material properties with fringing electric field dielectrometry sensors requires the processing of terminal admittance data from multiple electrode pairs. The choice of the algorithmic approach for data analysis is critical because of a high sensitivity to small measurement uncertainties. While individual channel uncertainties are usually within a reasonable instrumentation range, measurement of properties of multiple material layers fails unless special techniques are used to prevent numerical instabilities. This paper demonstrates the mechanism of uncertainty in a successive stair-step property estimation in which the estimates of one layer's properties are used to estimate the subsequent layer's properties. Three-wavelength measurements of dielectric permittivity and conductivity illustrate the problem in two-layer experimental setups. Limitations of the stair-step approach and possible future improvements are discussed.     

Comparison of metoprolol and sotalol in preventing ventricular tachyarrhythmias after the implantation of a cardioverter/defibrillator

The purpose of this prospective study was to evaluate, on an intention-to-treat basis, the efficacy of d,l-sotalol and metoprolol with regards to the recurrence of arrhythmic events after implantable cardioverter defibrillator (ICD) implantation. After ICD implantation, 70 patients were randomly assigned to treatment with either metoprolol (mean dosage 104+/-37 mg/day in 35 patients) or d,l-sotalol (mean dosage 242+/-109 mg/day in 35 patients). During follow up ventricular tachycardia (VT), fast VT, and ventricular fibrillation (VF) episodes were calculated. Metoprolol treatment led to a marked reduction in the recurrence of arrhythmic events. Actuarial rates for absence of VT recurrence at 1 and 2 years were significantly higher in the metoprolol group compared with the d,l-sotalol group (83% and 80% vs 57% and 51%, respectively, p=0.016). The actuarial rates for absence of fast VT or VF were 80% in the metoprolol group compared with 46% in the d,l-sotalol group (p=0.002). During a follow up of 26+/-16 months, there were 3 deaths in the metoprolol group compared with 6 deaths in the d,l-sotalol group. Actuarial rates of overall survival were not significantly different in the 2 groups (91% vs 83%, p=0.287). In this prospective, randomized, controlled study the recurrence rate of ventricular tachyarrhythmias in patients treated with metoprolol was lower than in patients treated by d,l-sotolol.     

Risk of thromboembolic events in patients with atrial flutter

Based on multiple studies, clear, guided anticoagulation therapy is recommended for patients with atrial fibrillation. The value of anticoagulation therapy in patients with atrial flutter, however, is less well established. Little is known about the incidence of thromboembolism in patients with atrial flutter. We evaluated the risk of thromboembolism in 191 consecutive unselected patients referred for treatment of atrial flutter. A history of embolic events was noted in 11 patients. Acute embolism (<48 hours) occurred in 4 patients (3 after direct current cardioversion, 1 after catheter ablation). During follow-up of 26+/-18 months, 9 patients experienced thromboembolic events. During the follow-up, the overall embolic event rate (including acute embolism and thromboembolic events during follow-up) was 7 % in this patient population. Risk indicators for an embolic event in an univariate analysis were organic heart disease (p = 0.037), depressed left ventricular function (p = 0.02), history of systemic hypertension (p = 0.004), and diabetes mellitus (p = 0.0038). Using multivariate analysis, a history of hypertension was the only independent predictor for elevated embolic risk in this patient population (odds ratio = 6.5; 95% confidence intervals 1.5 to 45). Thus, the thromboembolic risk is higher than previously recognized for patients with atrial flutter. Anticoagulation therapy may decrease this risk.     

Prediction of total body lipid from total body water in rats. Part 1. Relations between directly measured major body components

Aimed to the construction of a prediction equation for estimations of lipid content from animal water content body composition was determined by whole body analysis of male rats (1) given access, ad libitum, to a commercial standard diet (n = 144; ranging from 60 to 600 g in weight, and from the 4th to the 34th week of age), and (2) showing striking variations with regard to nutritional state, dietary history, enlarged fat deposition, genetic origin, intestinal microbial status, and advanced age (n = 75). It was shown that a unique coefficient of water content in lipid-free body mass does not exist. The results of statistical analysis for the grouped values of percentage body dry matter (x) and percentage body lipid (y) indicate that the latter can be estimated accurately from body water content directly determined by the use of the quadratic regression equation y = ?0.2864×+0.01615 x² with a standard deviation of the procedure s_y = ±1.40. This prediction equation is valid for a wide developmental span even under highly different experimental states. Differences between the calculated body lipid contents vs. analytically determined values are smaller than by using a linear regression equation or coefficient(s) of hydration of lipid-free body mass.     

Large contingency tables with large cell frequencies: A model search algorithm and alternative measures of fit.

A new search algorithm, the Generalized Guided Method, for locating a model for contingency tables and a measure of fit related to the R–2 of multiple regression are proposed for the analysis of contingency tables with many cells and large cell frequencies. This algorithm is designed to analyze contingency tables that contain dichotomous and/or nondichotomous (polytomous) variables. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DNA damage by PAH and repair in a marine sponge

The sponge Tethya lyncurium from the Northern Adriatic has been used as an experimental species.A method is outlined for preparation of DNA which yields a highly purified DNA with a double-strand (ds) molecular weight of 25 M-dalton between single-strand (ss) breaks, which when properly damaged can be cut opposite to ss-breaks with nuclease s₁. The molecular weights of the resulting ds-DNA pieces and their distribution has been evaluated by electron microscope photographs.Sponges exposed to benzo[a]pyrene (BaP) in the dark only incorporate BaP-derivatives (BaPD) in small amounts, if any. However, in the presence of light, derivatization to BaP derivatives enables effective coupling to occur, as shown previously (R. K. Zahn et al., 1981). Sponges were exposed to radiolabeled BaP in the presence of light. Coupling of BaPD to the DNA as well as the induction of ss-breaks were measured.Light-mediated coupling is concentration dependent from 0.01 – 20 ppb BaP with a correlation coefficient of r = 0.84.Under conditions of possible repair, ss-breaks completely disappear from sponge DNA in the course of three weeks while a substantial fraction of the BaP derivatives persists.Double label experiments show that substantial DNA synthesis occurs during this time. Pollution causes a decrease of the molecular weight of unnicked DNA, re-incubation in clean water an increase. A DNA species of 24 M-dalton seems to play a critical role. If its percentage in the DNA population drops below a critical level, recovery is not longer possible. DNA damage by PAH and repair in sponges seems to differ from that of most eucaryotes.     

Renaissance of beta blocker therapy in myocardial infarct

Beta-adrenergic blocking drugs have been evaluated for the treatment of arrhythmias and for the prevention of sudden cardia death, particularly in post-myocardial infarction patients. Betablockers have been demonstrated to reduce mortality, reinfarction, ventricular fibrillation and cardiac rupture in acute infarction. Therefore, in patients with suspected myocardial infarction and without contraindications, treatment with betablockers should be initiated early and continued for at least 2 years. Side-effects are mild and occur in approximately 10% of patients. Patients who have contraindications for betablockers use early in myocardial infarction should be reevaluated before discharge from the hospital and considered for such therapy. Because betablockers prevent some of the adverse arrhythmogenic mechanisms seen in chronic heart failure, it may be reasonable to expect that these drugs could have a role in preventing sudden cardiac death in these patients. Analysis of some of the betablocker post-infarction trials indicate that betablockers reduced the risk of sudden death in patients with heart failure at baseline. Some studies demonstrated also the symptomatic improvement following therapy with betablockers in patients with heart failure. But the currently available data are too limited to provide conclusive information.     

Grating lobe control in limited scan arrays

The use of multiple higher order modes for grating lobe control in arrays of large aperture elements scanned over restricted spatial sectors is described. Arrays of this type are useful in a number of applications including precision approach radar, weapons locators, and satellite communications systems. An extensive experimental and theoretical study that includes the design and use of dielectric lenses for control ofE-plane null filling for an eight-element array, the investigation of null width effects on sidelobe levels, the experimental study of an element and control circuitry for two-dimensional scan, bandwidth effects, and the use of dielectric spatial filters and row displacement for residual grating lobe suppression is summarized.     

Size estimation of pictures associated with success and failure as a function of manifest anxiety.

"An experiment was performed to test the hypothesis that the size of a picture associated with failure would be overestimated relative to that of a picture associated with success and control pictures primarily by Ss with high scores on the Taylor Manifest Anxiety Scale… . The results showed that, in accordance with the hypothesis, high MAS Ss significantly overestimated the size of the failure picture… but the low MAS group showed an insignificant trend in the opposite direction. In addition, it was shown that the 'psychological' anxiety items of the Taylor scale related significantly to the success-failure difference in size estimation, but the 'somatic' items did not." From Psyc Abstracts 36:02:2HK57Z. (PsycINFO Database Record (c) 2010 APA, all rights reserved)