608 research outputs found

    Binary vapour—liquid equilibria of methanol with sulfolane. Tetraethylene glycol dimethyl ether and 18-crown-6 = Phasengleichgewichte in binären systemen von Methanol mit Sulfolan, Tetraethylenglycoldimethylether und 18-krone-6 Kronenether

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    The activity coefficients of methanol in sulfolane, tetraethylene glycol dimethyl ether (TEGDME) and 18-crown-6 under conditions of equilibrium have been determined in the temperature range 423–503 K and in the pressure range 0.28–3.5 MPa. A minimum in the activity coefficient was found for the methanol—TEGDME and methanol—18-crown-6 solutions

    Management of the phosphorus-cladophora dynamic at a site on lake Ontario using a multi-module bioavailable P model

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    The filamentous green alga Cladophora grows to nuisance proportions in Lake Ontario. Stimulated by high phosphorus concentrations, nuisance growth results in the degradation of beaches and clogging of industrial water intakes with attendant loss of beneficial uses. We develop a multi-module bioavailable phosphorus model to examine the efficacy of phosphorus management strategies in mitigating nuisance algal growth. The model platform includes modules simulating hydrodynamics (FVCOM), phosphorus-phytoplankton dynamics (GEM) and Cladophora growth (GLCMv3). The model is applied along a 25 km stretch of the Lake Ontario nearshore, extending east from Toronto, ON and receiving effluent from three wastewater treatment plants. Simulation results identify the Duffin Creek wastewater treatment plant effluent as a driving force for nuisance conditions of Cladophora growth, as reflected in effluent bioavailable phosphorus concentrations and the dimensions of the plant’s phosphorus footprint. Simulation results demonstrate that phosphorus removal by chemically enhanced secondary treatment is insufficient to provide relief from nuisance conditions. Tertiary treatment (chemically enhanced secondary treatment with ballasted flocculation) is shown to eliminate phosphorus-saturated conditions associated with the Duffin Creek wastewater treatment plant effluent, providing local relief from nuisance conditions. Management guidance presented here has wider application at sites along the highly urbanized Canadian nearshore of Lake Ontario

    Management transition to the Great Lakes nearshore: Insights from hydrodynamic modeling

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    The emerging shift in Great Lakes management from offshore to nearshore waters will require attention to complexities of coastal hydrodynamics and biogeochemical transformations. Emphasizing hydrodynamics, this work resolves transport processes in quantifying discharge plume and pollutant of concern (POC) footprint dimensions, the latter being the portion of the plume where water quality standards are not met. A generic approach, isolated from pollutant-specific biokinetics, provides first-approximation estimates of the footprint area. A high-resolution, linked hydrodynamic-tracer model is applied at a site in the Greater Toronto Area on Lake Ontario. Model results agree with observed meteorological and hydrodynamic conditions and satisfactorily simulate plume dimensions. Footprints are examined in the context of guidelines for regulatory mixing zone size and attendant loss of beneficial use. We demonstrate that the ratio of the water quality standard to the POC concentration at discharge is a key determinant of footprint dimensions. Footprint size for traditional pollutants (ammonia, total phosphorus) meets regulatory guidelines; however, that for soluble reactive phosphorus, a presently unattended pollutant, is ~1–2 orders of magnitude larger. This suggests that it may be necessary to upgrade treatment technologies to maintain consistency with regulatory guidelines and mitigate manifestations of the eutrophication-related soluble reactive phosphorus POC

    Induced Anticlinic Ordering and Nanophase Segregation of Bow-Shaped Molecules in a Smectic Solvent

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    Recent experiments indicate that doping low concentrations of bent-core molecules into calamitic smectic solvents can induce anticlinic and biaxial smectic phases. We have carried out Monte Carlo (MC) simulations of mixtures of rodlike molecules (hard spherocylinders with length/breadth ratio Lrod/D=5L_{\rm rod}/D = 5) and bow- or banana-shaped molecules (hard spherocylinder dimers with length/breadth ratio Lban/D=5L_{ban}/D = 5 or 2.5 and opening angle ψ\psi) to probe the molecular-scale organization and phase behavior of rod/banana mixtures. We find that a low concentration (3%) of Lban/D=5L_{ban}/D = 5 dimers induces anticlinic (SmCA_A) ordering in an untilted smectic (SmA) phase for 100∘≤ψ<150∘100^\circ \le \psi < 150^\circ. For smaller ψ\psi, half of each bow-shaped molecule is nanophase segregated between smectic layers, and the smectic layers are untilted. For Lban/D=2.5L_{ban}/D = 2.5, no tilted phases are induced. However, with decreasing ψ\psi we observe a sharp transition from {\sl intralamellar} nanophase segregation (bow-shaped molecules segregated within smectic layers) to {\sl interlamellar} nanophase segregation (bow-shaped molecules concentrated between smectic layers) near ψ=130∘\psi = 130^\circ. These results demonstrate that purely entropic effects can lead to surprisingly complex behavior in rod/banana mixtures.Comment: 5 pages Revtex, 7 postscript figure

    Investigations of the structure of a cholesteric phase with a temperature induced helix inversion and of the succeeding S*C phase in thin liquid crystal cells

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    Investigations of 4-[(S, S)-2, 3 epoxyhexyloxy]-phenyl-4-(decyloxy)-benzoate by polarizing microscopy, the Cano-Grandjean method, optical rotation dispersion and UV-VIS spectroscopy reveal a cholesteric phase with temperature induced reversal of the helical twist. Switching time experiments in the S*C phase show that the intrinsic helix can be unwound reversibly and irreveribly by application of electric fields of different strengths

    What Research Ethics Should Learn from Genomics and Society Research: Lessons from the ELSI Congress of 2011

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    Research on the ethical, legal, and social implications (ELSI) of human genomics has devoted significant attention to the research ethics issues that arise from genomic science as it moves through the translational process. Given the prominence of these issues in today's debates over the state of research ethics overall, these studies are well positioned to contribute important data, contextual considerations, and policy arguments to the wider research ethics community's deliberations, and ultimately to develop a research ethics that can help guide biomedicine's future. In this essay, we illustrate this thesis through an analytic summary of the research presented at the 2011 ELSI Congress, an international meeting of genomics and society researchers. We identify three pivotal factors currently shaping genomic research, its clinical translation, and its societal implications: (1) the increasingly blurred boundary between research and treatment; (2) uncertainty — that is, the indefinite, indeterminate, and incomplete nature of much genomic information and the challenges that arise from making meaning and use of it; and (3) the role of negotiations between multiple scientific and non-scientific stakeholders in setting the priorities for and direction of biomedical research, as it is increasingly conducted “in the public square.

    ORMIR_XCT: A Python package for high resolution peripheral quantitative computed tomography image processing

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    High resolution peripheral quantitative computed tomography (HR-pQCT) is an imaging technique capable of imaging trabecular bone in-vivo. HR-pQCT has a wide range of applications, primarily focused on bone to improve our understanding of musculoskeletal diseases, assess epidemiological associations, and evaluate the effects of pharmaceutical interventions. Processing HR-pQCT images has largely been supported using the scanner manufacturer scripting language (Image Processing Language, IPL, Scanco Medical). However, by expanding image processing workflows outside of the scanner manufacturer software environment, users have the flexibility to apply more advanced mathematical techniques and leverage modern software packages to improve image processing. The ORMIR_XCT Python package was developed to reimplement some existing IPL workflows and provide an open and reproducible package allowing for the development of advanced HR-pQCT data processing workflows

    Exposição à teratógenos e anormalidades oculares congênitas em pacientes brasileiros portadores da sequência de Möbius

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    Purpose: To assess the sociodemographic profiles, teratogen exposures, and ocular congenital abnormalities in Brazilian patients with Möbius sequence. Method: Forty-four patients were recruited from the Brazilian Möbius Sequence Society. This cross-section comprised 41 patients (age, mean ± standard deviation, 9.0 ± 5.5 years) who fulfilled the inclusion criteria. The parent or caregiver answered a questionnaire regarding sociodemographic data and pregnancy history. Patients underwent ophthalmological assessments. They were subdivided into groups according to misoprostol exposure during pregnancy, and the two groups were compared. Results: Mothers/caregivers reported unplanned pregnancies in 36 (88%) cases. Of these, 19 (53%) used misoprostol during their first trimesters. A stable marital status tended to be more frequent in the unexposed group (P=0.051). Incomplete elementary school education was reported by two (11%) mothers in the exposed group and by three (14%) mothers in the unexposed group (P=0.538). The mothers' gestational exposures to cocaine, marijuana, alcohol, and cigarettes were similar in both groups (P=0.297, P=0.297, P=0.428, and P=0.444, respectively). One (5%) case of Rubella infection during pregnancy was found in the unexposed group. The main malformations in the exposed and unexposed groups were the following: strabismus (72% and 77%, respectively), lack of emotional tearing (47% and 36%, respectively), and lagophthalmos (32% and 41%, respectively). Conclusion: Stable marital statuses tended to be more frequent among mothers that did not take misoprostol during pregnancy. Exposures to other teratogens and the main ocular abnormalities were similar in both groups.Objetivo: Descrever o perfil sóciodemográfico, exposição à teratógenos e anormalidades oculares congênitas em pacientes brasileiros portadores da sequência de Möbiu Método: Quarenta e quatro pacientes recrutados da Sociedade Brasileira de Sequência de Möbius foram examinados. Este estudo transversal incluiu 41 pacientes que preencheram os critérios de inclusão do estudo (média das idades: 9,0 ± 5,5 anos). Mãe/responsável dos pacientes responderam a um questionário sobre perfil sóciodemográfico e história gestacional. Foi realizado exame oftalmológico de todos os pacientes. Eles foram agrupados em dois grupos de acordo com a exposição ao misoprostol durante a gestação e seus dados foram comparados. Resultados: Mães/responsáveis referiram gravidez indesejada em 36 (88%) dos casos. Destas, 19 (53%) fizeram uso de misoprostol no primeiro trimestre de gestação. Houve uma tendência do grupo de mães não expostas ao misoprostol de terem um estado civil estável (P=0,051). Duas (11%) mães do grupo de expostas ao misoprostol relataram primeiro grau incompleto e três (14%) do grupo de não expostas (P=0,538). A exposição das mães à cocaína, maconha, álcool e cigarro foi similar em ambos os grupos (P=0,297, P=0,297, P=0,428, P=0,444, respectivamente). Houve um caso (5%) de Rubéola no grupo de mães não expostas. As principais malformações associadas nos pacientes expostos e não expostos foram, respectivamente: estrabismo (72% e 77%), e diminuição da lágrima emocional (47% e 36%) e lagoftalmia (32% and 41%). Conclusão: Estado civil estável foi mais frequente em mães que não fizeram uso de misoprostol durante a gestação. Exposição à outros teratógenos e malformações oculares tiveram distribuição semelhante em ambos os grupos.Fundação Altino Ventura Department of OphthalmologyHospital de Olhos de Pernambuco Department of OphthalmologyUniversity of Illinois Department of Ophthalmology &amp; Visual ScienceUniversidade Federal de São Paulo (UNIFESP) Department of OphthalmologyAssociação de Assistência à Criança DeficienteSanta Casa de Misericórdia de São Paulo Department of OphthalmologyUniversidade de São Paulo Faculdade de Medicina Departments of Neurology and PediatricsUniversidade de São Paulo Instituto de Biociências Department of BiologyUniversidade de São Paulo Department of OphthalmologyUniversidade Federal de Pernambuco Department of Pediatric SurgeryUniversidade de São Paulo Department of PsychiatryServices Group in Epileptic Child PsychiatryInstituto Cema Department of OphthalmologyUNIFESP, Department of OphthalmologySciEL

    Social interaction, noise and antibiotic-mediated switches in the intestinal microbiota

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    The intestinal microbiota plays important roles in digestion and resistance against entero-pathogens. As with other ecosystems, its species composition is resilient against small disturbances but strong perturbations such as antibiotics can affect the consortium dramatically. Antibiotic cessation does not necessarily restore pre-treatment conditions and disturbed microbiota are often susceptible to pathogen invasion. Here we propose a mathematical model to explain how antibiotic-mediated switches in the microbiota composition can result from simple social interactions between antibiotic-tolerant and antibiotic-sensitive bacterial groups. We build a two-species (e.g. two functional-groups) model and identify regions of domination by antibiotic-sensitive or antibiotic-tolerant bacteria, as well as a region of multistability where domination by either group is possible. Using a new framework that we derived from statistical physics, we calculate the duration of each microbiota composition state. This is shown to depend on the balance between random fluctuations in the bacterial densities and the strength of microbial interactions. The singular value decomposition of recent metagenomic data confirms our assumption of grouping microbes as antibiotic-tolerant or antibiotic-sensitive in response to a single antibiotic. Our methodology can be extended to multiple bacterial groups and thus it provides an ecological formalism to help interpret the present surge in microbiome data.Comment: 20 pages, 5 figures accepted for publication in Plos Comp Bio. Supplementary video and information availabl
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