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Homogenous
Terms modified by Homogenous Selected AbstractsInteractive soft-touch dynamic deformationsCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3 2007Hui Chen Abstract It is crucial for the users to touch, grasp and manipulate the interested objects through our sense of touch in many interactive applications, such as on-line computer games, interactive cartoon design, and virtual prototyping. In this paper, we propose an interactive haptic deformation approach which incorporates the dynamic simulation of mass,spring systems and flexible control of free-form deformation in the touch-enabled soft-object deformation. Through distributing mass, spring and damping coefficients of the object to the bounded Bezier volume lattice, the deformation of the object related to the haptic avatar follows the physical laws and has high working rate. Both homogenous and inhomogenous materials are simulated. The anchor nodes of haptic input are specified to create amazing special effects during the interactive haptic deformation. Interactive haptic deformations of three-type tropic fishes, Angel, Demekin, and GuppyBlueGrass, have been experimented to simulate vivid fish swimming processes in the virtual ocean scene. Our proposed approach provides touch-enabled input and efficient performance in the flexible deforming controls, letting the objects move in a dynamic, cartoon-style deforming manner. Copyright © 2007 John Wiley & Sons, Ltd. [source] Thermally Conducting Partially Ionized Plasma in a Variable Magnetic FieldCONTRIBUTIONS TO PLASMA PHYSICS, Issue 3 2007S. Shaikh Abstract An infinitely extending homogenous partially ionized plasma endowed with several physical mechanisms and permeated by a variable magnetic field is considered. The combined effect of these parameters, namely, Hall currents, finite conductivity, ion viscosity, collision with neutrals and thermal conductivity on the gravitational instability of the plasma is studied. It is found that the several mechanisms play different physical roles in the perturbed problem. Jeans' Criterion is analyzed in the framework of Tsallis' statistics for possible modifications due to the presence of nonextensive effects. A simple generalization of the Jeans' criterion is obtained and the standard values are obtained in the limiting case q = 1, q being the nonextensive parameter. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A CASE OF DUODENAL LIPOMA REMOVED BY ENDOSCOPIC POLYPECTOMYDIGESTIVE ENDOSCOPY, Issue 4 2004Tuyoshi Shoji A rare case of duodenal lipoma removed by endoscopic polypectomy is presented herein. A 64-year-old female was found to have a polypoid lesion in the duodenum on gastrointestinal endoscopic examination. Endoscopy revealed a submucosal tumor located on the second portion. Endoscopic ultrasonography (EUS) demonstrated a homogenous, hyperechoic mass continuous with the submucosal layer, suggesting a lipoma. Because of the likelihood of the tumor ultimately causing obstruction or bleeding, endoscopic polypectomy was performed. There were no complications after treatment. [source] Myocardial Viability Detected by Myocardial Contrast Echocardiography,Prognostic Value in Patients after Myocardial InfarctionECHOCARDIOGRAPHY, Issue 4 2010Maria Olszowska M.D., Ph.D. Objective: This study aimed to assess the role of myocardial contrast echocardiography (MCE) as a predictor of cardiac events and death in patients with acute myocardial infarction (AMI). Methods: Eighty-six patients underwent primary percutaneous coronary angioplasty for AMI. Segmental perfusion was estimated by MCE in real time at mean 5 days after PCI using low MI (0.3) after 0.3,0.5 ml bolus injection of intravenous Optison. MCE was scored semiquantitatively as: (1) normal perfusion (homogenous contrast effect), (2) partial perfusion (patchy myocardial contrast enhancement), (3) lack of perfusion (no visible contrast effect). A contrast score index (CSI) was calculated as the sum of MCE scores in each segment divided by the total number of segments. The patients were followed up for cardiac events and death. Results: A CSI of >1.68 was taken to be a predictor of cardiac events and death. Death occurred only in patients with CSI >1.68. Patients with CSI >1.68 had a significantly (P = 0.03) higher incidence of cardiac death or cardiac events (75%) compared to those with CSI <1.68 (27%). The absence of residual perfusion within the infarct zone was an independent predictor of death and cardiac events (P = 0.02). Conclusions: The absence of residual myocardial viability in the infarct zone supplied by an infarct-related artery is a powerful predictor of cardiac events in patients after AMI. (Echocardiography 2010;27:430-434) [source] Effects of Acer platanoides invasion on understory plant communities and tree regeneration in the northern Rocky MountainsECOGRAPHY, Issue 5 2005Kurt O. Reinhart Quantitative studies are necessary to determine whether invasive plant species displace natives and reduce local biodiversity, or if they increase local biodiversity. Here we describe the effects of invasion by Norway maple Acer platanoides on riparian plant communities and tree regeneration at two different scales (individual tree vs stand scales) in western Montana, USA, using both descriptive and experimental approaches. The three stands differed in community composition with the stand most dominated by A. platanoides invasion being more compositionally homogenous, and less species rich (,67%), species even (,40%), and diverse (,75%) than the two other stands. This sharp decrease in community richness and diversity of the highly invaded stand, relative to the other stands, corresponded with a 28-fold increase in A. platanoides seedlings and saplings. The dramatic difference between stand 1 vs 2 and 3 suggests that A. platanoides invasion is associated with a dramatic change in community composition and local loss of species diversity; however, other unaccounted for differences between stands may be the cause. These whole-stand correlations were corroborated by community patterns under individual A. platanoides trees in a stand with intermediate levels of patchy invasion. At the scale of individual A. platanoides canopies within a matrix of native trees, diversity and richness of species beneath solitary A. platanoides trees declined as the size of the trees increased. These decreases in native community properties corresponded with an increase in the density of A. platanoides seedlings. The effect of A. platanoides at the stand scale was more dramatic than at the individual canopy scale; however, at this smaller scale we only collected data from the stand with intermediate levels of invasion and not from the stand with high levels of invasion. Transplant experiments with tree seedlings demonstrated that A. platanoides seedlings performed better when grown beneath conspecific canopies than under natives, but Populus and Pinus seedlings performed better when grown beneath Populus canopies, the dominant native. Our results indicate that A. platanoides trees suppress most native species, including the regeneration of the natural canopy dominants, but facilitate conspecifics in their understories. [source] Recent Updates of Chemically Modified Electrodes in Analytical ChemistryELECTROANALYSIS, Issue 13 2003Jyh-Myng Zen Abstract This review article updates recent developments in chemically modified electrodes (CMEs) towards analytical applications for the year of 2000,2002 with 179 references. The broad topics are subdivided into four main categories: i) physisorption/chemisorption, ii) covalently linked, iii) homogenous (uniform) multilayer and iv) heterogeneous (non-uniform) multilayer CMEs. The criteria for the preparation of CMEs in elecrocatalytic systems are clearly described in Section 1. Some of the encouraging results related to Au-nanoparticles for DNA detection and new ceramic carbon, carbon nanotubes, copper-plated screen-printed and Nafion/lead ruthenate pyrochlore CMEs for catalytic application were especially discussed in this review. [source] In vitro study of mean loads and modes of failure of all-ceramic crowns cemented with light-cured or dual-cured luting cement, after 1 and 30 d of storageEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2008Melissa-L. This study compared the mean loads and modes of failure of teeth restored with all-ceramic crowns (ACCs) cemented with dual-cured (RelyX ARC; 3M ESPE) or light-cured (RelyX Veneer; 3M ESPE) luting cements. Clinically, there are advantages of light-cured cements over the recommended dual-cured cements, namely increased working time, improved handling, colour stability, and a homogenous mix. Forty, sound, extracted, human, premolar teeth underwent a standardized preparation for ACCs. IPS Empress (Ivoclar-Vivadent) crowns of standard dimensions were fabricated and 20 were cemented with each cement. The crowns were stored for 1 or 30 d in water and subjected to a compressive load to failure at 0.017 mm s,1. There were no significant differences in loads at failure, between each cement group, at each storage period, and there were no significant differences in loads at failure, for each cement, at 1 and 30 d of storage. There were also no significant differences in modes of failure between each cement group. Before recommending light-cured cement as an alternative to dual-cured cement for the cementation of all-ceramic crowns, further research is required to establish the depth of ceramic at which light-cured lutes fail to polymerize completely. [source] Predicting creep crack initiation in austenitic and ferritic steels using the creep toughness parameter and time-dependent failure assessment diagramFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 10 2009C. M. DAVIES ABSTRACT Methods for evaluating the creep toughness parameter, Kmatc, are reviewed and Kmatc data are determined for a ferritic P22 steel from creep crack growth tests on compact tension, C(T), specimens of homogenous parent material (PM) and heterogeneous specimen weldments at 565 °C and compared to similar tests on austenitic type 316H stainless steel at 550 °C. Appropriate relations describing the time dependency of Kmatc are determined accounting for data scatter. Considerable differences are observed in the form of the Kmatc data and the time-dependent failure assessment diagrams (TDFADs) for both the 316H and P22 steel. The TDFAD for P22 shows a strong time dependency, but is insensitive to time for 316H. Creep crack initiation (CCI) time predictions are obtained using the TDFAD approach and compared to experimental results from C(T) specimens and feature components. The TDFAD based on parent material properties can be used to obtain conservative predictions of CCI on weldments. Conservative predictions are almost always obtained when lower bound Kmatc values are employed. Long-term test are generally more relevant to industrial component lifetimes. The different trends between long- and short-term CCI time and growth data indicate that additional long-term test are required to further validate the procedure to predict the lifetimes of high temperature components. [source] Common genetic influences underlie comorbidity of migraine and endometriosisGENETIC EPIDEMIOLOGY, Issue 2 2009Dale R. Nyholt Abstract We examined the co-occurrence of migraine and endometriosis within the largest known collection of families containing multiple women with surgically confirmed endometriosis and in an independent sample of 815 monozygotic and 457 dizygotic female twin pairs. Within the endometriosis families, a significantly increased risk of migrainous headache was observed in women with endometriosis compared to women without endometriosis (odds ratio [OR] 1.57, 95% confidence interval [CI]: 1.12,2.21, P=0.009). Bivariate heritability analyses indicated no evidence for common environmental factors influencing either migraine or endometriosis but significant genetic components for both traits, with heritability estimates of 69 and 49%, respectively. Importantly, a significant additive genetic correlation (rG = 0.27, 95% CI: 0.06,0.47) and bivariate heritability (h2=0.17, 95% CI: 0.08,0.27) was observed between migraine and endometriosis. Controlling for the personality trait neuroticism made little impact on this association. These results confirm the previously reported comorbidity between migraine and endometriosis and indicate common genetic influences completely explain their co-occurrence within individuals. Given pharmacological treatments for endometriosis typically target hormonal pathways and a number of findings provide support for a relationship between hormonal variations and migraine, hormone-related genes and pathways are highly plausible candidates for both migraine and endometriosis. Therefore, taking into account the status of both migraine and endometriosis may provide a novel opportunity to identify the genes underlying them. Finally, we propose that the analysis of such genetically correlated comorbid traits can increase power to detect genetic risk loci through the use of more specific, homogenous and heritable phenotypes. Genet. Epidemiol. 2008. © 2008 Wiley-Liss, Inc. [source] A Modular Injection System, Multilevel Sampler, and Manifold for Tracer TestsGROUND WATER, Issue 6 2003Brian J. Mailloux Ground water injection and sampling systems were developed for bacterial transport experiments in both homogenous and heterogeneous unconsolidated, surficial aquifers. Two types of injection systems, a large single tank and a dynamic mixing tank, were designed to deliver more than 800 L of amended ground water to the aquifer over 12 hours, without altering the ground water temperature, pH, Eh, or dissolved gas composition. Two types of multilevel samplers (MLSs) were designed and installed. Permanent MLSs performed well for the homogenous surficial aquifer, but their installation procedure promoted vertical mixing, which could obfuscate experimental data obtained from vertically stratified, heterogeneous aquifers. A novel, removable MLS was designed to fit in 2- and 4-inch wells. Expandable O-rings between each sampling port hydraulically isolated each port for sample collection when a nut was tightened at the land surface. A low-cost vacuum manifold system designed to work with both MLS designs used 50 mL centrifuge tubes to efficiently sample 12 MLS ports with one peristaltic pump head. The integrated system was developed and used during four field campaigns over a period of three years. During each campaign, more than 3000 ground water samples were collected in less than one week. This system should prove particularly useful for ground water tracer, injection, and push-pull experiments that require high-frequency and/or high-density sampling. [source] Preparation, Bioactivity, and Drug Release of Hierarchical Nanoporous Bioactive Glass Ultrathin FibersADVANCED MATERIALS, Issue 6 2010Youliang Hong Hierarchical nanoporous bioactive glass ultrathin fibers with different pore diameters from 1.5-nm micropores up to 65-nm macropores are synthesized using P123,PEO co-templates and an electrospinning technique (see image). Experiments demonstrate that the prepared bioactive glass fibers are highly homogenous and bioactive and their nanopores can control drug release well. [source] A Question of Rites?HISTORY COMPASS (ELECTRONIC), Issue 5 2006Perspectives on the Colonial Encounter with Sati Although a rare occurrence, sati has become a highly controversial issue in modern India. In the wake of the now notorious burning of Roop Kanwar in 1987, sati and its glorification became a terrain on which wider issues about religion, identity, modernity and tradition were contested. In this debate both supporters and opponents of sati invoked the rhetoric of ,rights'. It is generally agreed that such terms in the contemporary debate have their roots in the colonial period; some supporters of sati go as far as to argue that those who condemn sati as a violation of women's rights are adopting a ,Western' perspective without appreciating sati's ,true' social, religious and cultural significance. In doing so, however, they assume a homogenous and consistent colonial condemnation of sati. New perspectives suggest, however, that the British response to sati was more multifaceted than this allows and the link between colonial discourses and modern protagonists more complex. [source] The selection and evolution of viral quasispecies in HIV-1 infected childrenHIV MEDICINE, Issue 1 2002P Nowak Objectives To analyse the diversity and divergence of the viral populations in three mother,child pairs in longitudinally obtained samples for up to 7 years. Methods Peripheral blood mononuclear cells were obtained from three mothers at delivery and three to four samples were obtained from each of their children from 1.5 months up to 78 months of age. The V3 region of HIV-1 was amplified by polymerase chain reaction, cloned and sequenced. HIV-1 DNA sequence comparisons were performed by phylogenetic analysis. Results The viral population was initially homogenous in two children but highly heterogeneous in one child. Three patterns of vertical transmission seemed to have occurred: transmission of the most prevalent maternal strain, of a minor maternal strain and of multiple maternal strains. In one child, a possible reappearance of a maternal sequence was observed at 34 months of age. Conclusions Children may become infected with the most prevalent maternal strain, a minor maternal variant or multiple maternal quasispecies. Maternal viral variants may reappear in children after several years of infection and could possibly be derived from a reservoir of founder quasispecies established during the children's primary HIV-1 infection. [source] Functional connectivity of default mode network components: Correlation, anticorrelation, and causalityHUMAN BRAIN MAPPING, Issue 2 2009Lucina Q. Uddin Abstract The default mode network (DMN), based in ventromedial prefrontal cortex (vmPFC) and posterior cingulate cortex (PCC), exhibits higher metabolic activity at rest than during performance of externally oriented cognitive tasks. Recent studies have suggested that competitive relationships between the DMN and various task-positive networks involved in task performance are intrinsically represented in the brain in the form of strong negative correlations (anticorrelations) between spontaneous fluctuations in these networks. Most neuroimaging studies characterize the DMN as a homogenous network, thus few have examined the differential contributions of DMN components to such competitive relationships. Here, we examined functional differentiation within the DMN, with an emphasis on understanding competitive relationships between this and other networks. We used a seed correlation approach on resting-state data to assess differences in functional connectivity between these two regions and their anticorrelated networks. While the positively correlated networks for the vmPFC and PCC seeds largely overlapped, the anticorrelated networks for each showed striking differences. Activity in vmPFC negatively predicted activity in parietal visual spatial and temporal attention networks, whereas activity in PCC negatively predicted activity in prefrontal-based motor control circuits. Granger causality analyses suggest that vmPFC and PCC exert greater influence on their anticorrelated networks than the other way around, suggesting that these two default mode nodes may directly modulate activity in task-positive networks. Thus, the two major nodes comprising the DMN are differentiated with respect to the specific brain systems with which they interact, suggesting greater heterogeneity within this network than is commonly appreciated. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source] Adaptive ICT procedure for non-linear seepage flows with free surface in porous mediaINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 3 2002N. H. Sharif Abstract This paper focuses on adaptive finite element (FE)-methods for computation of the motion of viscous fluid interfaces fundamentally encountered in multiphase flow problems in porous media. An interface capturing technique (ICT)-procedure is formulated with a stabilized finite element scheme in a Eulerian framework to solve the two-dimensional (2D) and three-dimensional (3D) Navier,Stokes equation in porous media. Global mesh refinements of the discretized domain and local mesh refinements in the vicinity of the interface are used for the spatial discretization. The ICT is embedded into the finite element scheme by adding an extra advection equation and an additional unbounded degree of freedom to the number of the unknowns. Problems of non-linear free surface seepage flow in earth-fill dams are simulated in order to validate the performance of the FE-ICT. Computations for steady non-linear seepage flows in 2D and 3D are obtained for homogenous, isotropic and isothermal porous media. Copyright © 2002 John Wiley & Sons, Ltd. [source] Hybrid-stress solid elements for shell structures based upon a modified variational functionalINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2002K. Y. Sze Abstract In this paper, we start with a modified generalized laminate stiffness matrix that serves as a remedy to resolve the thickness locking and some abnormalities encountered by solid-shell elements in laminate analyses. A modified Hellinger,Reissner functional having displacement and a set of generalized stresses as independent fields is devised. Based upon the functional, eight-node and 18-node hybrid-stress solid-shell elements are proposed. A number of benchmark tests on homogenous and laminated plates/shells are conducted. The accuracy of the elements is promising. Copyright © 2002 John Wiley & Sons, Ltd. [source] The computation of deterministic bounds to multiplexed MPEG video traffic using z -characterizationINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2004Wai-Chung Poon Abstract In this paper, we propose a method called z -characterization for computing the deterministic bounds of an aggregated MPEG stream at frame level. Traditional deterministic characterization methods like empirical envelope generally suffer from the drawback of high computation complexity. In our approach, the I, P and B sub-traces of an MPEG trace will be characterized independently such that they possess their own empirical envelopes. By exploiting the periodic group-of-pictures (GOP) structure of MPEG video, the I, P and B sub-envelopes can act as building blocks for computing the characterization of the aggregate stream in real-time. Experimental results show that our proposed characterization closely bounds the empirical envelope in both homogenous and heterogeneous multiplexing scenarios. Copyright © 2004 John Wiley & Sons, Ltd. [source] Assessment of sun reactive skin type with multiple correspondence analysis, hierarchical and tree-structured classification methodsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2002C. Guinot Synopsis The sun reactive skin type classification is based on sunburn susceptibility, tanning ability and phenotypic information. As subjects rarely match all features of a given skin type, the attribution to a class is partially subjective. The aims of the study, were to analyse the contribution of each characteristic to the classification made by the expert, and to establish a classification based on a statistical approach conducted on 212 women living in the Ile-de-France area. Multiple regression was used to construct a formula for each phototype. The coefficients obtained demonstrated that the importance of each characteristic was extremely variable from one phototype to another, suggesting that the phototype determination could be facilitated by adding a weight for every characteristic in the decision. Then, multiple correspondence analysis and clustering analysis methods showed that one phototype could be divided into two more homogenous classes. Résumé La classification du phototype, reflet de la protection naturelle de la peau au soleil, repose sur la susceptibilitéà prendre des coups de soleil, la capacitéà bronzer et trois informations phénotypiques. En pratique, les individus présentant rarement l'ensemble des caractéristiques prévues pour un phototype donné, la décision de l'expert d'attribuer un sujet particulier à une classe repose sur une part de subjectivité. Le but de cette étude, conduite sur 212 femmes volontaires d'Ile-de-France, était d'analyser la contribution de chacune des caractéristiques dans le processus de classification effectué par l'expert pour déterminer le phototype, et de proposer une classification reposant sur une approche statistique. Une équation de régression multiple a été construite pour chacun des phototypes représentés dans l'échantillon. Les coefficients obtenus ont démontré que l'importance accordée en pratique à chaque caractéristique était très variable d'un phototype à l'autre, suggérant que la détermination du phototype pourrait être facilitée par la mise en place d'une pondération des caractéristiques dans la règle de décision. Les méthodes d'analyse factorielle des correspondances multiples et de classification ascendante hiérarchique ont ensuite montré que les sujets de l'un des phototypes pourraient être répartis en deux classes plus homogènes, les autres classes demeurant globalement inchangées par rapport à leur définition originelle. [source] Variability in TRBV haplotype frequency and composition in Caucasian, African American, Western African and Chinese populationsINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 6 2005J. L. Brzezinski Summary The polymorphic T-cell receptor V, (TRBV) genes encode much of the variable region of the T-cell receptor , chain. Analysis of allele frequencies of three closely linked polymorphic TRBV genes, TRBV7-3, TRBV9 and TRBV6-4, was undertaken in several populations. The frequencies of these alleles are not significantly different in populations of Caucasians, African Americans and Western Africans. However, Chinese population is extremely homogenous at all three loci. The current study identifies the existence of haplotypic relationships between alleles of these genes in the Caucasian population. The ORF allele TRBV7-3*A3 is found exclusively on chromosomes bearing TRBV9*A2 and TRBV6-4*A2 in this cohort. In contrast, TRBV7-3*A1 and the null allele TRBV7-3*A2 are associated only with TRBV9*A1 and TRBV6-4*A1. This pattern of linkage disequilibrium (LD) is altered in the African American and Western African populations. In these cohorts, there is a marked reduction in LD between alleles of TRBV7-3 and TRBV9. This study is consistent with previous population genetic studies wherein African-derived samples have a greater level of genetic diversity compared to Caucasians. These data also demonstrate that patterns of LD are not consistent across the entire TRBV locus. [source] Patterns of pseudo-reticulocytosis in malaria: fluorescent analysis with the Cell-Dyn® CD4000INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1 2002C. S. SCOTT This study of Plasmodium falciparum malaria evaluated patterns of fluorescent reticulocyte measurements as determined with the Abbott Cell-Dyn® CD4000. The parasitaemia of positive samples (n=180) ranged from 0.04% to 25.5%, with those (19/180) showing gametocytes having lower parasitaemia levels (mean 0.31%, median 0.2%) compared to those that did not (mean 2.59%, median 0.8%). There was a reasonable association (R2=0.60) between parasitaemia level and CD4000 reticulocyte percentages, although there was overall a small statistical bias towards higher parasitaemia estimates determined microscopically. Consistently high immature reticulocyte fraction (IRF) values of >0.5 were observed in cases with a parasitaemia exceeding 5%, while samples with lower parasitaemia levels showed more variable IRF values. Visual examination of CD4000 reticulocyte histograms revealed that 81/100 malaria-positive samples with an IRF above 0.5 showed the presence of a fluorescent population `spike' consistent with the staining of intracellular malaria parasites. Only three of the 80 malaria-positive samples with an IRF below 0.5, and none of the 237 malaria-negative samples, showed this histogram pattern. These observations indicate that samples with malaria parasites give erroneously high CD4000 reticulocyte estimates that essentially comprise the sum total of true reticulocytes and parasite-infected red cells (pseudo-reticulocytes). This limitation is common to all automated reticulocyte procedures but recognizing the differences between homogenous staining parasitized red cells and heterogeneous staining reticulocytes has potential applications in monitoring parasitaemia levels both at patient presentation and during subsequent treatment. [source] Cardiovascular Disease Is Associated with Greater Incident Dehydroepiandrosterone Sulfate Decline in the Oldest Old: The Cardiovascular Health Study All Stars StudyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 3 2010Jason L. Sanders BA OBJECTIVES: To describe cross-sectional and longitudinal associations with dehydroepiandrosterone sulfate (DHEAS) and change in DHEAS with age. DESIGN: Longitudinal cohort study. SETTING: Pittsburgh, Pennsylvania. PARTICIPANTS: Cardiovascular Health Study All Stars study participants assessed in 2005/06 (N=989, mean age 85.2, 63.5% women, 16.5% African American). MEASUREMENTS: Health characteristics were assessed in 2005/06 according to DHEAS level, mean DHEAS and DHEAS change across age categories were tested, and linear and logistic regression was used to identify factors present in 1996/97 associated with continuous and categorical DHEAS change. RESULTS: Mean ± standard deviation DHEAS was 0.555 ± 0.414 ,g/mL in 1996/97 and 0.482 ± 0.449 ,g/mL in 2005/06 for women and 0.845 ± 0.520 ,g/mL in 1996/97 and 0.658 ± 0.516 ,g/mL in 2005/06 for men. In 2005/06, DHEAS was lower in women and subjects with cardiovascular disease (CVD) and chronic pulmonary disease and higher for African Americans and subjects with hypertension and high cholesterol. Mean DHEAS change was greater in men (,0.200 ,g/mL) than in women (,0.078 ,g/mL) (P<.001). Each 1-year increase in age attenuated the effect of male sex by 0.01 ,g/mL (P=.009), abolishing the sex difference in DHEAS change by age 79. Presence of CVD before the study period was associated with greater absolute DHEAS change (,=,0.04 ,g/mL, P=.04) and with the fourth quartile of DHEAS change versus the first to third quartiles (odds ratio=1.46, 95% confidence interval=1.03,2.05). CONCLUSION: DHEAS change continues into very old age, is not homogenous, is affected by sex, and is associated with prevalent CVD. Future studies should investigate factors that might accelerate DHEAS decline. [source] Structure of the human tibialis anterior tendonJOURNAL OF ANATOMY, Issue 4 2000WOLF PETERSEN The structure and vascular pattern of the human tibialis anterior tendon was investigated using injection techniques, light and transmission electron microscopy and immunohistochemistry. From the well vascularised peritenon, blood vessels penetrate the tendon tissue and anastomose with a longitudinally oriented intratendinous network. The distribution of blood vessels within the tibialis anterior tendon was not homogenous. The posterior part of the tendon had a complete vascular network that extends from the musculotendinous junction to the insertion at the first metatarsal and medial cuneiform bones. In the anterior half, the tissue was avascular in a zone with a length of 45,67 mm. This zone was covered by a single layer (,30 ,m) of oval shaped cells. Transmission electron microscopy showed that these cells have the characteristics of chondroid cells. This region was stained by Alcian blue at pH 1 which indicates a high concentration of acid glycosaminoglycans and immunohistochemical staining for chondroitin-4-sulphate, chondroitin-6-sulphate and aggrecan was positive. However, immunostaining for the typical cartilage specific type II collagen within this zone was negative. The location of the avascular zone corresponds to the region where the tibialis anterior tendon wraps around the superior and inferior retinacula which serve as fibrous pulleys. This is the region where most spontaneous ruptures of the tibialis anterior tendon occur. The presence of fibrocartilage within gliding tendons is a functional adaptation to compressive and shearing forces. In contrast to reports from the literature about the structure of gliding tendons wrapping around a bony pulley, the gliding zone of the tibialis anterior tendon has only a narrow layer of chondroid cells and proof of type II collagen is lacking. [source] Modelling the trend and seasonals within an AIDS model of the demand for alcoholic beverages in the United KingdomJOURNAL OF APPLIED ECONOMETRICS, Issue 2 2002I. A. Moosa The argument that is put forward in this paper is that failure to represent stochastic trend and stochastic seasonality in an AIDS model leads to a misspecified and possibly structurally unstable model. This proposition is verified by estimating an AIDS model of the demand for alcoholic beverages in the United Kingdom. Three versions of the model are estimated, and it is demonstrated that the version allowing for stochastic trend and stochastic seasonality performs better than the other two versions of the model in terms of the diagnostics tests and goodness of fit measures. The best estimated model turns out to possess the properties of having common components and being homogenous. Further empirical testing reveals the presence of stochastic trends and cointegration between the budget shares of beer and wine. The results clearly indicate that there has been a shift away from the consumption of beer towards wine. Copyright © 2002 John Wiley & Sons, Ltd. [source] Kinetics of methyl methacrylate grafting polymerization onto flaky aluminum powderJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Hui Liu Abstract With ammonium persulfate (APS) as the initiator, the kinetics of methyl methacrylate (MMA) grafting polymerization onto flaky aluminum powder (Al) was studied. It was found that the experimental apparent grafting polymerization rate, Rg = KC × C × C, was basically consistent with the theoretical result based on the theory of stable polymerization and equivalent activity, Rg = KC × C × CMMA. The activation energy of grafting, homogenous, and total polymerization rate was calculated as 65.1, 35.4, and 37.5 kJ mol,1, respectively. It could be validated that the relationship among these activation energies accorded with the theoretical result of parallel reactions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Genotypic and phenotypic characteristics of antibiotic-producing soil Streptomyces investigated by RAPD-PCRJOURNAL OF BASIC MICROBIOLOGY, Issue 1 2003Raad Gharaibeh Random amplified polymorphic DNA (RAPD) analysis has been used to determine the relatedness of 73 antibiotic-producing soil Streptomyces isolates that were recovered from different soil habitats in Jordan based on their RAPD-PCR fingerprints. Genetic polymorphisms between these isolates showed three common bands of 2777, 800 and 250 bp shared by approximately (95%) of them. Some specific bands were also observed. Further analysis of RAPD patterns with the UPGMA resulted in clustering the tested isolates into two main super clusters. Super cluster I was more homogenous than super cluster II and contained all the reference strains. However, super cluster II consists of unrelated isolates within five small groups. As RAPD fingerprints of the tested isolates linked to their phenotypes, differentiation between isolates with different cultural properties was observed. [source] Clinical Application of PET/CT Fusion Imaging for Three-Dimensional Myocardial Scar and Left Ventricular Anatomy during Ventricular Tachycardia AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2009JING TIAN M.D., Ph.D. Background: Image integration has the potential to display three-dimensional (3D) scar anatomy and facilitate substrate characterization for ventricular tachycardia (VT) ablation. However, the current generation of clinical mapping systems cannot display 3D left ventricle (LV) anatomy with embedded 3D scar reconstructions or allow display of border zone and high-resolution anatomic scar features. Objective: This study reports the first clinical experience with a mapping system allowing an integrated display of 3D LV anatomy with detailed 2D/3D scar and border zone reconstruction. Methods: Ten patients scheduled for VT ablation underwent contrast-enhanced computed tomography (CT) and Rubidium-82 perfusion/F-18 Fluorodeoxyglucose metabolic Positron Emission Tomography (PET) imaging to reconstruct 3D LV and scar anatomy. LV and scar models were co-registered using a 3D mapping system and analyzed with a 17-segment model. Metabolic thresholding was used to reconstruct the 3D border zone. Real-time display of CT images was performed during ablation. Results: Co-registration (error 4.3 ± 0.7 mm) allowed simultaneous visualization of 3D LV anatomy and embedded scar and guided additional voltage mapping. Segments containing homogenous or partial scar correlated in 94.4% and 85.7% between voltage maps and 3D PET scar reconstructions, respectively. Voltage-defined scar and normal myocardium had relative FDG uptakes of 40 ± 13% and 89 ± 30% (P < 0.05). The 3D border zone correlated best with a 46% metabolic threshold. Real-time display of registered high-resolution CT images allowed the simultaneous characterization of scar-related anatomic changes. Conclusion: Integration of PET/CT reconstruction allows simultaneous 3D display of myocardial scar and border zone embedded into the LV anatomy as well as the display of detailed scar anatomy. Multimodality imaging may enable a new image-guided approach to substrate-guided VT ablation. [source] Cellular organization and appearance of differentiated structures in developing stages of the parasitic platyhelminth Echinococcus granulosusJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2005Claudio Martínez Abstract Echinococcus granulosus is the causative agent of hydatidosis, a major zoonoses that affects humans and herbivorous domestic animals. The disease is caused by the pressure exerted on viscera by hydatid cysts that are formed upon ingestion of E. granulosus eggs excreted by canine. Protoscoleces, larval forms infective to canine, develop asynchronously and clonally from the germinal layer (GL) of hydatid cysts. In this report, we describe the cellular organization and the appearance of differentiated structures both in nascent buds and developed protoscoleces attached to the GL. Early protoscolex morphogenesis is a highly complex and dynamic process starting from the constitution of a foramen in the early bud, around which nuclei are distributed mainly at the lateral and apical regions. Similarly, distribution of nuclei in mature protoscoleces is not homogenous but underlies three cellular territories: the suckers, the rostellar pad, and the body, that surrounds the foramen. Several nuclei are associated to calcareous corpuscles (Cc), differentiated structures that are absent in the earlier bud stages. The number of nuclei is similar from the grown, elongated bud stage to the mature protoscolex attached to the GL, strongly suggesting that there is no significant cellular proliferation during final protoscolex development. The amount of DNA per nucleus is in the same range to the one described for most other platyhelminthes. Our results point to a sequential series of events involving cell proliferation, spatial cell organization, and differentiation, starting in early buds at the GL of fertile hydatid cysts leading to mature protoscoleces infective to canine. © 2004 Wiley-Liss, Inc. [source] Determination of cut-off titers and agreement between immunofluorescence and immunoblotting methods for detecting antinuclear antibodies in childrenJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2010G. Aksu Abstract Detection of antinuclear antibodies (ANA) is a diagnostic adjunct in patients with suspected autoimmune connective tissue diseases, and various detection methods are in use. The aim of this study was to analyze the agreement between the ANA immunoflourescence (IF) and immunoblotting (IB) methods and determine cut-off for children subjects in a laboratory setting. We evaluated 729 serum samples that were analyzed by both ANA IF and IB. The results were evaluated by ,2 test and, for agreement, , index was used. Frequencies determined for both 1:40,1:100 cut-off titers of ANA IF in relation to IB testing supported the idea that 1:100 starting dilution should be recommended in children subjects for ANA IF method and antigen specific immunoblot testing was needed, especially for some of the ANA IF negative samples. Agreement between the two methods, especially with homogenous, granular, and nucleolar ANA IF patterns, was statistically significant. J. Clin. Lab. Anal. 24:230,236, 2010. © 2010 Wiley-Liss, Inc. [source] Beyond natives and immigrants: exploring types of net generation studentsJOURNAL OF COMPUTER ASSISTED LEARNING, Issue 5 2010G. Kennedy Abstract Previously assumed to be a homogenous and highly skilled group with respect to information and communications technology, the so-called Net Generation has instead been shown to possess a diverse range of technology skills and preferences. To better understand this diversity, we subjected data from 2096 students aged between 17 and 26 from three Australian universities to a cluster analysis. Through this analysis, we identified four distinct types of technology users: power users (14% of sample), ordinary users (27%), irregular users (14%) and basic users (45%). A series of exploratory chi-square analyses revealed significant associations between the different types of technology users and the university that students attended, their gender and age and whether the student was local or international. No associations were found for analyses related discipline area, socio-economic status or rurality of residence. The findings are discussed in light of the rhetoric associated with commentaries about the Net Generation, and suggestions about their implications for teaching and learning in universities are offered. [source] Kin recognition and cannibalism in a subsocial spiderJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2001T. Bilde Evolution of cooperation and group living in spiders from subsocial family groups may be constrained by their cannibalistic nature. A tendency to avoid cannibalizing kin may facilitate tolerance among spiders and implies the ability to identify relatives. We investigated whether the subsocial spider Stegodyphus lineatus discriminates kin by recording cannibalism among juveniles in experiments during which amount of food and size difference among spiders in groups were varied. We hypothesized that family groups should be less cannibalistic than groups of mixed-parental origin. Further, we tested whether food-stress would influence cannibalism rates differently in kin and nonkin groups and the effect of relatedness on cannibalism within groups of spiders of variable size compared with those of homogenous size. In groups of six spiders, more spiders were cannibalized in nonsib groups than in sib groups under low food conditions. A tendency for nonkin biased cannibalism in starved spider pairs supported that kin recognition in S. lineatus is expressed when food is limited. Size variance of individuals within well-fed groups of siblings and unrelated spiders had no influence on cannibalism rates. Apparently, both hunger and high density are important promoters of cannibalism. In addition to inclusive fitness benefits, we suggest that an ability to avoid cannibalizing kin will favour the evolution of cooperation and group living in phylogenetically pre-adapted solitary species. [source] | ||||||||||||||||||||||||||||||||||||||||||||||