Accelerated Life Test Planning With Independent Weibull Competing Risks With Known Shape Parameter

This article presents methodology for accelerated life test (ALT) planning when there are two or more failure modes, or competing risks which are dependent on one accelerating factor. It is assumed that the failure modes have respective latent (unobservable) failure times, and the minimum of these times corresponds to the product lifetime. The latent failure times are assumed to be s-independently distributed Weibull with known, common shape parameter. Expressions for the Fisher information matrix, and test plan criteria are presented. The methodology is applied to the ALT of Class-H insulation for motorettes, where temperature is the accelerating factor. Two-level, and 4:2:1 allocation test plans based on determinants, and on estimating quantiles or hazard functions, are presented. Sensitivity of optimal test plans to the specified Weibull shape parameter is also studied     

The influence of hydrogen and nitrogen on the formation of Si nanoclusters embedded in sub-stoichiometric silicon oxide layers

This work reports the study concerning the influence of the preparation conditions on the structure of silicon rich oxide (SRO) deposited by PECVD method by which the structural properties of the film are strictly related. In particular we investigated the role of reactant gases N₂O and SiH₄ on the total Si concentration, Si excess concentration, Si clustered concentration and size of nanoclusters formed by high annealing temperature. We payed particular attention on the role of the hydrogen and nitrogen during the Si agglomeration.The presence of hydrogen atoms on the as-deposited specimen, confirmed by the Si–H bonds peak on the FTIR analysis, has been directly correlated to the silicon excess concentration in the layer. The silicon, oxygen and nitrogen atomic density has been calculated from RBS analysis. These information were coupled to the ones obtained using methodology based on electron energy loss spectroscopy combined with energy filtered images, which allowed us to quantify the clustered silicon concentration in annealed sub-stoichiometric silicon oxide layers (SiO_x). We have verified that the nitrogen dissolved in the layer inhibits the Si excess clustering so that the efficiency of silicon agglomeration process decreases as the nitrogen content increases.     

On the use of genuine-impostor statistical information for score fusion in multimodal biometrics/sur l’usage de l’information statistioue client-imposteur pour la fusion des scores en biométrie multimodale

Matching score level fusion techniques in multimodal person verification conventionally use global score statistics in the normalization and fusion stages. In this paper, novel normalization and fusion methods are presented to take advantage of the separate statistics of the monomodal scores in order to reduce the genuine and impostor pdf lobe overlapping and improve the verification rate. Joint mean normalization is an affine transformation that normalizes the mean of the monomodal biometrics scores separately for the genuine and impostor individuals. Histogram equalization is used to align the statistical distribution of the monomodal scores and make the whole separate statistics comparable. The presented weighting fusion methods have been designed to minimize the variances of the separate multimodal statistics and reduce the multimodal pdf lobe overlapping. The results obtained in speech and face scores fusion upon polycost and xm2vts databases show that the proposed techniques provide better results than the conventional methods.     

Water and phosphoric acid uptake of poly [2,5-benzimidazole] (ABPBI) membranes prepared by low and high temperature casting

Phosphoric acid-doped membranes based in poly[2,5-benzimidazole] (ABPBI) were obtained by a new low temperature casting procedure and by the classical high temperature casting from methanesulfonic acid. These membranes, which can be suitable for application in direct methanol proton exchange membrane (PEM) fuel cells, were studied in relation with their phosphoric acid doping level by measuring the free and bonded acid. The water isotherms were also determined for the low and high temperature casted ABPBI membranes. Both, acid and water sorption properties, were compared with those determined in poly [2-2′-(m-fenylene)-5-5′ bibenzimidazole] (PBI) membranes. The water sorption of the ABPBI membranes over the range of all water activity is described by the modified BET equation, commonly known as Guggenheim–Anderson–de Boer (GAB) and a two-parameters empirical isotherm. The acid uptake behaviour of the membranes prepared by low and high temperature casting are related with differences in their supramolecular structure.     

Pharmacokinetics and retinal toxicity of intravitreal liposome-encapsulated 5-fluorouridine

Relationships from benefits-costs analyses in radiography are presented. The impact of several factors (equipment, frequency of examinations, ...) on the planning of a department and special financial aspects, e.g., leasing of equipment, are discussed. The cost relationships of conventional versus digital radiography are demonstrated for the example of a 1000-bed hospital.     

An interactive package for the computer-aided design of woven fabrics

In the textile Industry, the design of new fabrics requires interactive facilities for the specification of the weaving parameters, their modification and the simulation of the weaving result. In the present paper, an interactive package for the design of woven fabrics is presented. It allows the hierarchical specification of three kinds of yarns and contains simple tools for the modification of the colors through the definition of color maps. The internal data structure is discussed, together with the user interface. Some weaving examples are presented.     

Infra-red characterization of carbonization of Si surfaces by gas source molecular beam epitaxy

The carbonization and epitaxial growth of cubic SiC films on Si(100) substrates using C₂H₂ and solid Si sources has been investigated by means of infra-red Fourier transform spectroscopy. The carbonization of the Si surface is performed under continuous C₂H₂ flux in two steps: an ordinary process, plus an increase of the substrate temperature to its final value. Subsequent epitaxial films were grown under simultaneous supply of elemental Si and C₂H₂ gas beam. Infra-red reflectivity spectra of samples under different conditions are reported and permit the direct verification for the presence of SiC in carbonized layers, measure the thickness of the films and evaluate their quality.     

Fine structural analysis of the epithelial cells in the hepatopancreas of Palaemonetes argentinus (Crustacea, Decapoda, Caridea) in intermoult.

The aim of this study is to describe the ultrastructure of the hepatopancreas of P. argentinus in intermoult. P. argentinus hepatopancreas was studied using standard TEM techniques. Each tubule consists of four cellular types: E (embryonic), F (fibrillar), R (resorptive) and B (blister like). E-cells have embryonic features and some of them were found in mitosis. F, R and B cells possess an apical brush border. F-cells have a central or basal nucleus, a conspicuous RER, and dilated Golgi cisternae. R cells show a polar organization of organelles in three areas: apical, with numerous mitochondria and sER tubules, a central area with the nucleus and RER, and a basal area containing a sER-like tubule system and mitochondria. B-cells were observed at different stages of their life cycle. In an early differentiation stage they comprise an apical endocytotic complex and Golgi vesicles. The fusion of endocytotic and Golgi vesicles originates subapical vacuoles. During maturation, a big central vacuole is formed by coalescence of subapical vacuoles. The central vacuole is eliminated by holocrine secretion. The ultrastructure suggests that F-cells synthesize proteins, R-cells storage nutrients and B-cells have a secretory or excretory function, and confirms the independent origin of F, B and R cells from the embryonic cells.     

Rationally and empirically derived dimensions of children's symptomatology: Expert ratings and confirmatory factor analyses of the CBCL.

Expert ratings and confirmatory factor analyses were used to develop an alternative system for scoring the Child Behavior Checklist (CBCL; T. M. Achenbach, 1991) to measure specific dimensions corresponding to current conceptualizations of child symptomatology. Data were from a nonclinic and 2 independent clinic samples. Subscales measuring Anxiety, Attention Problems/Hyperactivity, Conduct Problems, Depression, Oppositional Defiant, Social Problems/Immaturity, and Somatization were created. Logistic regressions were conducted to evaluate the diagnostic efficiency and discrimination of the new and original approaches to scoring the CBCL. Some of the new subscales demonstrated better sensitivity, positive predictive power, and discriminant validity than the original CBCL subscales; however, subscales from both approaches demonstrated low sensitivity. Results support the use of the new subscales for specific research purposes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Both Specific Endothelial and Proximal Tubular Adam17 Deletion Protect against Diabetic Nephropathy

ADAM17 is a disintegrin and metalloproteinase capable of cleaving the ectodomains of a diverse variety of molecules including TNF-α, TGF-α, L-selectin, and ACE2. We have previously demonstrated that renal ADAM17 is upregulated in diabetic mice. The role of endothelial (eAdam17) and proximal tubular (tAdam17) Adam17 deletion in renal histology, modulation of the renin angiotensin system (RAS), renal inflammation, and fibrosis was studied in a mouse model of type 1 Diabetes Mellitus. Moreover, the effect of Adam17 deletion in an in vitro 3D cell culture from human proximal tubular cells under high glucose conditions was evaluated. eAdam17 deletion attenuates renal fibrosis and inflammation, whereas tAdam17 deletion decreases podocyte loss, attenuates the RAS, and decreases macrophage infiltration, α-SMA and collagen accumulation. The 3D in vitro cell culture reinforced the findings obtained in tAdam17KO mice with decreased fibrosis in the Adam17 knockout spheroids. In conclusion, Adam17 deletion either in the endothelial or the tubular cells mitigates kidney injury in the diabetic mice by targeting different pathways. The manipulation of Adam17 should be considered as a therapeutic strategy for treating DN.