Outbreak of serogroup C meningococcal disease associated with campus bar patronage

Between February 1991 and April 1992, eight undergraduates at a US residential university and one at a nearby 2-year college contracted serogroup C meningococcal disease. A case-control investigation with 20 controls per case, oropharyngeal carriage surveys, and multilocus enzyme electrophoresis (MEE) of serogroup C isolates were used to identify factors contributing to the outbreak. All eight sterile-site isolates from cases were closely related by MEE and were similar (though not identical) to the strain associated with the 1991-1992 epidemic of meningococcal disease in eastern Canada. Disease was associated with cigarette smoking (p = 0.012), recent patronage of campus-area bars (p = 0.034), estimated amount of time spent in campus-area bars (p = 0.0003), and, especially, recent patronage of one specific bar, bar A (p = 0.0006; odds ratio = 23.1, 95% confidence interval 3.0-571.5). In carriage surveys, 1,528 throat cultures taken from (primarily student) noncases yielded only five (0.3%) strains that were identical by MEE to those from cases. Two of these were found among 22 cultures obtained from bar A employees in spring 1992. Some cases in this outbreak may have followed transmission of the epidemic strain in bar A. Campus bar environments may facilitate the spread of meningococcal disease among teenagers and young adults.     

Bacillary angiomatosis and bacillary peliosis in patients infected with human immunodeficiency virus: clinical characteristics in a case-control study

Clinical characteristics associated with bacillary angiomatosis and bacillary peliosis (BAP) in patients with human immunodeficiency virus (HIV) infection were evaluated in a case-control study; 42 case-patients and 84 controls were matched by clinical care institution. Case-patients presented with fever (temperature, > 37.8 degrees C; 93%), a median CD4 lymphocyte count of 21/mm3, cutaneous or subcutaneous vascular lesions (55%), lymphadenopathy (21%), and/or abdominal symptoms (24%). Many case-patients experienced long delays between medical evaluation and diagnosis of BAP (median, 4 weeks; range, 1 day to 24 months). Case-patients were more likely than controls to have fever, lymphadenopathy, hepatomegaly, splenomegaly, a low CD4 lymphocyte count, anemia, or an elevated serum level of alkaline phosphatase (AP) (P < .001). In multivariate analysis, a CD4 lymphocyte count of < 200/mm3 (matched odds ratio [OR], 9.9; P < .09), anemia reflected by a hematocrit value of < 0.36 (OR, 19.7; P < .04), and an elevated AP level of > or = 2.6 mukat/L (OR, 23.9; P < .05) remained associated with disease after therapy with zidovudine was controlled for. BAP should be considered an AIDS-defining opportunistic infection and should be included in the differential diagnosis for febrile, HIV-infected patients with cutaneous or osteolytic lesions, lymphadenopathy, abdominal symptoms, anemia, or an elevated serum level of AP.     

Singularity Analysis of Lower Mobility Parallel Manipulators Using Grassmann–Cayley Algebra

This paper introduces a methodology to analyze geometrically the singularities of manipulators, of which legs apply both actuation forces and constraint moments to their moving platform. Lower mobility parallel manipulators and parallel manipulators, of which some legs have no spherical joint, are such manipulators. The geometric conditions associated with the dependency of six PlUumlcker vectors of finite lines or lines at infinity constituting the rows of the inverse Jacobian matrix are formulated using Grassmann-Cayley algebra (GCA). Accordingly, the singularity conditions are obtained in vector form. This study is illustrated with the singularity analysis of four manipulators.     

Genetic Correlational Analyses of Ethanol Reward and Aversion Phenotypes in Short-Term Selected Mouse Lines Bred for Ethanol Drinking or Ethanol-Induced Conditioned Taste Aversion.

Short-term selective breeding created mouse lines divergent for ethanol drinking (high drinking short-term selected line [STDRHI], low drinking [STDRLO]) or ethanol-induced conditioned taste aversion (CTA; high [HTA], low [LTA]). Compared with STDRLO, STDRHI mice consumed more saccharin and less quinine, exhibited greater ethanol-induced conditioned place preference (CPP), and showed reduced ethanol stimulation and sensitization under some conditions; a line difference in ethanol-induced CTA was not consistently found. Compared with LTA, HTA mice consumed less ethanol but were similar in saccharin consumption, sensitivity to ethanol-induced CPP, and ethanol-induced locomotor stimulation and sensitization. These data suggest that ethanol drinking is genetically associated with several reward-and aversion-related traits. The interpretation of ethanol-induced CTA as more genetically distinct must be tempered by the inability to test the CTA lines beyond Selection Generation 2. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using Hazard Functions to Assess Changes in Processing Capacity in an Attentional Cuing Paradigm.

Processing capacity-defined as the relative ability to perform mental work in a unit of time-is a critical construct in cognitive psychology and is central to theories of visual attention. The unambiguous use of the construct, experimentally and theoretically, has been hindered by both conceptual confusions and the use of measures that are at best only coarsely mapped to the construct. However, more than 25 years ago, J. T. Townsend and F. G. Ashby (1978) suggested that the hazard function on the response time (RT) distribution offered a number of conceptual advantages as a measure of capacity. The present study suggests that a set of statistical techniques, well-known outside the cognitive and perceptual literatures, offers the ability to perform hypothesis tests on RT-distribution hazard functions. These techniques are introduced, and their use is illustrated in application to data from the contingent attentional capture paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comments on solid state hydrogen storage systems design for fuel cell vehicles

In recent years, significant research and development efforts were spent on hydrogen storage technologies with the goal of realizing a breakthrough for fuel cell vehicle applications. This article scrutinizes design targets and material screening criteria for solid state hydrogen storage. Adopting an automotive engineering point of view, four important, but often neglected, issues are discussed: 1) volumetric storage capacity, 2) heat transfer for desorption, 3) recharging at low temperatures and 4) cold start of the vehicle. The article shall help to understand the requirements and support the research community when screening new materials.     

Development of a class-specific ELISA for sulfonylurea herbicides (sulfuron screen)

The development of a direct competitive ELISA for the detection of a broad range of sulfonylurea herbicides (SUs) is described. Polyclonal antibodies were generated in rabbits using three different immunizing haptens. Antiserum with the broadest specificity was obtained with a mesosulfuronbenzylamine derivative which was coupled via a succinic acid spacer to keyhole limpet hemocyanine. A heterologous enzyme tracer which did not contain the succinic acid bridge was prepared using activated horseradish peroxidase. The direct competitive ELISA was optimized and applied for spiked tap and surface water samples. From 30 SUs, 8 compounds showed a molar cross-reactivity (CR) higher than 100% (this value was set for the hapten) and 11 compounds CRs between 10% and 100%. The ELISA can detect 16 SUs at a concentration of 0.1 microg/L or lower. Different surface and tap water samples were spiked with chlorimuron ethyl, metsulfuron methyl, or primisulfuron methyl at concentrations of 100, 200, or 500 ng/L and subsequently analyzed by both ELISA and HPLC-UV. Correlation analysis revealed good agreement between both methods (r2 = 0.983/0.948/0.982; n = 21 for each analyte). Using ELISA, no sample pretreatment other than filtration was necessary.     

Interactive volume rendering of thin thread structures within multivalued scientific data sets

We present a threads and halos representation for interactive volume rendering of vector-field structure and describe a number of additional components that combine to create effective visualizations of multivalued 3D scientific data. After filtering linear structures, such as flow lines, into a volume representation, we use a multilayer volume rendering approach to simultaneously display this derived volume along with other data values. We demonstrate the utility of threads and halos in clarifying depth relationships within dense renderings and we present results from two scientific applications: visualization of second-order tensor valued magnetic resonance imaging (MRI) data and simulated 3D fluid flow data. In both application areas, the interactivity of the visualizations proved to be important to the domain scientists. Finally, we describe a PC-based implementation of our framework along with domain specific transfer functions, including an exploratory data culling tool, that enable fast data exploration.     

Correlation entre les courbes courant-tension et la morphologie des dépôts électrolytiques d'étain

Résumé En contrÔlant le transport de matière par diffusion au sein de l'électrolyte au moyen d'une électrode à disque tournant, on étudie le mécanisme de lélectrocristallisation de l'étain en milieu phénolsulfonique. Les courbes courant-tension stationnaires et les diagrammes d'impédance peuvent s'expliquer par la coexistence d'au moins trois espèces adsorbées à l'interface métal-electrolyte. L'apparition des trois variétés morphologiques (spongieuse, compacte, puis dendritique) de dépÔt observées lorsqu'on augmente la densité de courant suggère, d'une manière analogue à l'électrocristallisation du zinc, l'intervention d'un processus autocatalytique dans le mécanisme réactionnel de décharge des ions Sn²⁺ et son couplage avec la diffusion superficielle d'adions du type Sn _ads ⁺ . La compétition entre l'adsorption d'hydrogène, capable d'inhiber la décharge des ions Sn²⁺, et ce processus autocatalytique explique que, dans les conditions stationnaires, la courbe courant-tension soit parallèle à l'axe des courants dans une certaine gamme de densités de courant.L'addition de dihydroxydiphenylsulfone dans l'électrolyte, qui élargit le domaine des densités de courant intermédiaires où le dépÔt reste compact, modifie la cinétique de l'électrocristallisation en ayant pour effet de réduire l'importance relative du processus autocatalytique dans le mécanisme réactionnel.

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The mechanism of the electrocrystallization of tin in a phenolsulphonic bath is studied by using a rotating disc electrode. The current-voltage curves plotted under steady-state conditions and the impedance diagrams can be explained by the coexistence of at least three adsorbed species at the metal-electrolyte interface. The three kinds of deposit morphology (spongy, compact, and dendritic) which are observed with increasing current density suggests, as in the case of zinc electrocrystallization, the coupling of an autocatalytic step occurring at the interface with the surface diffusion of adions such as Sn _ads ⁺ . The competition between this autocatalytic step and the hydrogen adsorption, which is able to inhibit the discharge of Sn²⁺ ions, explains why the steady-state current-voltage curves are parallel to the current axis in a certain range of current density.With small amounts of dihydroxydiphenylsulphone in the electrolyte, the range of current density leading to compact deposits is widened. It is shown that the additive changes the coupling of the processes taking place at the interface and seems to decrease the importance of the autocatalytic step in the reaction mechanism.