358 research outputs found

    Cathodoluminescence Image Processing of High TC Superconductors

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    Cathodoluminescence (CL) in the Scanning Electron Microscope (SEM) was performed for both ceramic pellets and thin films of YBaCuO high TC superconductors. Image processing provided additional quantitative information. For single phase films, we demonstrated the possibility to create thickness maps in real time from the CL pictures. The gradual thickness variation within the sample was revealed by the histogram of the thickness image. The continuity of the film was observed at a few threshold thicknesses values, defined by the fraction of the occupied area. At the conduction threshold value, the location and width of the conducting paths could be estimated. The analysis was of a lateral resolution better than 1 μm and of a submicron thickness resolution. Insulating impurity grains embedded in the YBaCuO ceramic pellet, which could not be recognized by secondary electrons, were revealed by the CL mode in the SEM. Their long luminescence lifetime was recorded at different time scales and provided an estimation of the lifetime and density of generated carriers. This analysis can be applied to any other high TC superconductors

    Osmolality of liquid oral medicines

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    Osmolalidad, como pH y viscosidad son parámetros a considerar para la administración de fármacos por sonda pospilórica. Si bien la literatura no es exactamente coincidente, la osmolalidad no debería ser mayor a 500-600 mOsm/kg ya que valores superiores podrían causar distensión abdominal e irritación de la mucosa intestinal. Este dato no se encuentra disponible en la información provista por el laboratorio para las formas farmacéuticas líquidas orales. Objetivos: Determinación de la osmolalidad de 16 presentaciones líquidas de uso oral: jarabes, soluciones y suspensiones, comercializadas en la República Argentina. Materiales y métodos: Se realizó un estudio observacional con 16 medicamentos elegidos al azar en formas farmacéuticas líquidas, entre las cuales se incluyeron diferentes marcas de un mismo principio activo. Se determinó su osmolalidad (en mOsm/kg de H2O) con un osmómetro μOSMETTE Model 5004 de PRECISION SYSTEMS. Resultados y discusión: De las presentaciones medidas, 12 tienen una osmolalidad superior a 600 mOsm/kg, por lo que requerirán ser diluidas para su administración pospilórica. Dis- tintas especialidades con un mismo principio activo dan valores muy diferentes, depen- diendo de sus excipientes. Conclusiones: Debe tenerse en cuenta los diferentes valores de osmolalidad que presentan distintas especialidades conteniendo un mismo principio activo. Ante la dificultad que im- plica su determinación y el probable error que se cometería al utilizar información prove- niente de otros países, sería útil que la osmolalidad fuera incluida como parte de la información del medicamento, especificando si es conveniente diluirlo para esta forma de administración.Osmolality as well as pH and viscosity are parameters to take into account when me- dicines must be administered via long enteral feeding tubes. Literature is not coincident about osmolality limits, but it shouldn ́t be over 500- 600 mOsm/Kg because it could produce abdominal pain and irritation of the intestinal mucose. This fact is not included by the manufacturers in the product information in our country. Objective: To determine osmolality of 16 different oral liquid medicines chosen ran- domly, syrups, solutions and suspensions, marketed in the Argentine Republic. Material and methods: An observational study was performed selecting randomly 16 liquid oral medicines, including different brands of the same active ingredient. Osmo- lality was determined, in mOsm/kg, by using an osmometer μOsmette Model 5004 from Precison Systems Results: 12 out of 16 had an osmolality over 600 mOsm/kg and should be diluted be- fore postpyloric administration. Different brands with the same active ingredient show very different values depending on their excipients. Conclusions: Different osmolalities of medicines containing the same active ingredient must be taken into account. Osmolality measurements are sometimes difficult to per- form and errors could be made if values from foreign medicines ́ brands are conside- red. It would be of great benefit if manufacturers included information about postpyloric administration of liquid medicines, especially if they must be diluted.Fil: Grunbaum, Julia E.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Lopez Holtmann, G. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Elesgaray, Rosana. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Ciencias Biológicas. Cátedra de Fisiología Humana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentin

    Decreased progenitor TCF1 + T-cells correlate with COVID-19 disease severity

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    COVID-19, caused by SARS-CoV-2, can lead to a severe inflammatory disease characterized by significant lymphopenia. However, the underlying cause for the depletion of T-cells in COVID-19 patients remains incompletely understood. In this study, we assessed the presence of different T-cell subsets in the progression of COVID-19 from mild to severe disease, with a focus on TCF1 expressing progenitor T-cells that are needed to replenish peripheral T-cells during infection. Our results showed a preferential decline in TCF1+ progenitor CD4 and CD8+ T-cells with disease severity. This decline was seen in various TCF1+ subsets including naive, memory and effector-memory cells, and surprisingly, was accompanied by a loss in cell division as seen by a marked decline in Ki67 expression. In addition, TCF1+ T-cells showed a reduction in pro-survival regulator, BcL2, and the appearance of a new population of TCF1 negative caspase-3 expressing cells in peripheral blood from patients with severe disease. The decline in TCF1+ T-cells was also seen in a subgroup of severe patients with vitamin D deficiency. Lastly, we found that sera from severe patients inhibited TCF1 transcription ex vivo which was attenuated by a blocking antibody against the cytokine, interleukin-12 (IL12). Collectively, our findings underscore the potential significance of TCF1+ progenitor T-cells in accounting for the loss of immunity in severe COVID-19 and outline an array of markers that could be used to identify disease progression

    Tetrachloroethylene (PCE, Perc) Levels in Residential Dry Cleaner Buildings in Diverse Communities in New York City

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    Fugitive tetrachloroethylene (PCE, perc) emissions from dry cleaners operating in apartment buildings can contaminate residential indoor air. In 1997, New York State and New York City adopted regulations to reduce and contain perc emissions from dry cleaners located in residential and other buildings. As part of a New York State Department of Health (NYSDOH) study, indoor air perc levels were determined in 65 apartments located in 24 buildings in New York City where dry cleaners used perc on site. Sampling occurred during 2001–2003, and sampled buildings were dispersed across minority and nonminority as well as low-income and higher income neighborhoods. For the entire study area, the mean apartment perc level was 34 μg/m(3), 10-fold lower than mean apartment levels of 340–360 μg/m(3) documented before 1997. The maximum detected perc level was 5,000 μg/m(3), 5-fold lower than the maximum of 25,000 μg/m(3) documented before 1997. Despite these accomplishments, perc levels in 17 sampled apartments still exceeded the NYSDOH residential air guideline of 100 μg/m(3), and perc levels in 4 sampled apartments exceeded 1,000 μg/m(3). Moreover, mean indoor air perc levels in minority neighborhoods (75 μg/m(3)) were four times higher than in nonminority households (19 μg/m(3)) and were > 10 times higher in low-income neighborhoods (256 μg/m(3)) than in higher income neighborhoods (23 μg/m(3)). Logistic regression suitable for clustered data (apartments within buildings) indicated that perc levels on floors 1–4 were significantly more likely to exceed 100 μg/m(3) in buildings located in minority neighborhoods (odds ratio = 6.7; 95% confidence interval, 1.5–30.5) than in nonminority neighborhoods. Factors that may be contributing to the elevated perc levels detected, especially in minority and low-income neighborhoods, are being explored

    Substance use and dietary practices among students attending alternative high schools: results from a pilot study

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    <p>Abstract</p> <p>Background</p> <p>Substance use and poor dietary practices are prevalent among adolescents. The purpose of this study was to examine frequency of substance use and associations between cigarette, alcohol and marijuana use and selected dietary practices, such as sugar-sweetened beverages, high-fat foods, fruits and vegetables, and frequency of fast food restaurant use among alternative high school students. Associations between multi-substance use and the same dietary practices were also examined.</p> <p>Methods</p> <p>A convenience sample of adolescents (n = 145; 61% minority, 52% male) attending six alternative high schools in the St Paul/Minneapolis metropolitan area completed baseline surveys. Students were participants in the Team COOL (Controlling Overweight and Obesity for Life) pilot study, a group randomized obesity prevention pilot trial. Mixed model multivariate analyses procedures were used to assess associations of interest.</p> <p>Results</p> <p>Daily cigarette smoking was reported by 36% of students. Cigarette smoking was positively associated with consumption of regular soda (p = 0.019), high-fat foods (p = 0.037), and fast food restaurant use (p = 0.002). Alcohol (p = 0.005) and marijuana use (p = 0.035) were positively associated with high-fat food intake. With increasing numbers of substances, a positive trend was observed in high-fat food intake (p = 0.0003). There were no significant associations between substance use and fruit and vegetable intake.</p> <p>Conclusions</p> <p>Alternative high school students who use individual substances as well as multiple substances may be at high risk of unhealthful dietary practices. Comprehensive health interventions in alternative high schools have the potential of reducing health-compromising behaviors that are prevalent among this group of students. This study adds to the limited research examining substance use and diet among at-risk youth.</p> <p>Trial registration number</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01315743">NCT01315743</a></p

    Smart Swarms of Bacteria-Inspired Agents with Performance Adaptable Interactions

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    Collective navigation and swarming have been studied in animal groups, such as fish schools, bird flocks, bacteria, and slime molds. Computer modeling has shown that collective behavior of simple agents can result from simple interactions between the agents, which include short range repulsion, intermediate range alignment, and long range attraction. Here we study collective navigation of bacteria-inspired smart agents in complex terrains, with adaptive interactions that depend on performance. More specifically, each agent adjusts its interactions with the other agents according to its local environment – by decreasing the peers' influence while navigating in a beneficial direction, and increasing it otherwise. We show that inclusion of such performance dependent adaptable interactions significantly improves the collective swarming performance, leading to highly efficient navigation, especially in complex terrains. Notably, to afford such adaptable interactions, each modeled agent requires only simple computational capabilities with short-term memory, which can easily be implemented in simple swarming robots

    Quantifying the interplay between environmental and social effects on aggregated-fish dynamics

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    Demonstrating and quantifying the respective roles of social interactions and external stimuli governing fish dynamics is key to understanding fish spatial distribution. If seminal studies have contributed to our understanding of fish spatial organization in schools, little experimental information is available on fish in their natural environment, where aggregations often occur in the presence of spatial heterogeneities. Here, we applied novel modeling approaches coupled to accurate acoustic tracking for studying the dynamics of a group of gregarious fish in a heterogeneous environment. To this purpose, we acoustically tracked with submeter resolution the positions of twelve small pelagic fish (Selar crumenophthalmus) in the presence of an anchored floating object, constituting a point of attraction for several fish species. We constructed a field-based model for aggregated-fish dynamics, deriving effective interactions for both social and external stimuli from experiments. We tuned the model parameters that best fit the experimental data and quantified the importance of social interactions in the aggregation, providing an explanation for the spatial structure of fish aggregations found around floating objects. Our results can be generalized to other gregarious species and contexts as long as it is possible to observe the fine-scale movements of a subset of individuals.Comment: 10 pages, 5 figures and 4 supplementary figure

    Measured body mass index, body weight perception, dissatisfaction and control practices in urban, low-income African American adolescents

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    <p>Abstract</p> <p>Background</p> <p>Current understanding of the associations between actual body weight status, weight perception, body dissatisfaction, and weight control practices among low-income urban African American adolescents is limited. The knowledge can help direct future intervention efforts.</p> <p>Methods</p> <p>Cross-sectional data including measured weight and height and self-reported weight status collected from 448 adolescents in four Chicago Public Schools were used.</p> <p>Results</p> <p>The prevalence of overweight and obesity (BMI ≥ 85<sup>th </sup>percentile) was 39.8%, but only 27.2% considered themselves as obese, although 43.4% reported trying to lose weight. Girls were more likely to express weight dissatisfaction than boys, especially those with BMI ≥ 95<sup>th </sup>percentile (62.9% vs. 25.9%). BMI ≥ 85<sup>th </sup>percentile girls were more likely to try to lose weight than boys (84.6% vs. 66.7%). Among all adolescents, 27.2% underestimated and 67.2% correctly judged their own weight status. Multinomial logistic models show that those with BMI ≥ 85<sup>th </sup>percentile, self-perceived as obese, or expressed body dissatisfaction were more likely to try to lose weight; adjusted odds ratios and 95% confidence intervals were 4.52 (2.53–8.08), 18.04 (7.19–45.30), 4.12 (1.64–10.37), respectively. No significant differences were found in diet and physical activity between those trying to lose weight and those not trying, but boys who reported trying to lose weight still spent more television time (P < 0.05).</p> <p>Conclusion</p> <p>Gender differences in weight perception, body dissatisfaction, and weight control practices exist among African American adolescents. One-third did not appropriately classify their weight status. Weight perception and body dissatisfaction are correlates of weight control practices. Adolescents attempting to lose weight need be empowered to make adequate desirable behavioral changes.</p

    Multi-scale Inference of Interaction Rules in Animal Groups Using Bayesian Model Selection

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    Inference of interaction rules of animals moving in groups usually relies on an analysis of large scale system behaviour. Models are tuned through repeated simulation until they match the observed behaviour. More recent work has used the fine scale motions of animals to validate and fit the rules of interaction of animals in groups. Here, we use a Bayesian methodology to compare a variety of models to the collective motion of glass prawns (Paratya australiensis). We show that these exhibit a stereotypical ‘phase transition’, whereby an increase in density leads to the onset of collective motion in one direction. We fit models to this data, which range from: a mean-field model where all prawns interact globally; to a spatial Markovian model where prawns are self-propelled particles influenced only by the current positions and directions of their neighbours; up to non-Markovian models where prawns have ‘memory’ of previous interactions, integrating their experiences over time when deciding to change behaviour. We show that the mean-field model fits the large scale behaviour of the system, but does not capture fine scale rules of interaction, which are primarily mediated by physical contact. Conversely, the Markovian self-propelled particle model captures the fine scale rules of interaction but fails to reproduce global dynamics. The most sophisticated model, the non-Markovian model, provides a good match to the data at both the fine scale and in terms of reproducing global dynamics. We conclude that prawns' movements are influenced by not just the current direction of nearby conspecifics, but also those encountered in the recent past. Given the simplicity of prawns as a study system our research suggests that self-propelled particle models of collective motion should, if they are to be realistic at multiple biological scales, include memory of previous interactions and other non-Markovian effects
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