11,109 research outputs found

    Impact of Driving Cycles on Greenhouse Gas (GHG) Emissions, Global Warming Potential (GWP) and Fuel Economy for SI Car Real World Driving

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    The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport: CO2, N2O and CH4 emissions as a function of engine warm up and driving cycles. Five different urban driving cycles were developed and used including free flow driving and congested driving. An in-vehicle FTIR (Fourier Transform Inferred) emission measurement system was installed on a EURO2 emission compliant SI (Spark Ignition) car for emissions measurement at a rate of 0.5 HZ under real world urban driving conditions. This emission measurement system was calibrated on a standard CVS (Constant Volume Sampling) measurement system and showed excellent agreement on CO2 measurement with CVS results. The N2O and CH4 measurement was calibrated using calibration gas in lab. A MAX710 real time in-vehicle fuel consumption measurement system was installed in the test vehicle and real time fuel consumption was then obtained. The temperatures across the TWC (Three Way Catalyst) and engine out exhaust gas lambda were measured. The GHG (greenhouse gas) mass emissions and consequent GWP (Global Warming Potential) for different urban diving conditions were analyzed and presented. The results provided a better understanding of traffic related greenhouse gas emission profile in urban area and will contribute to the control of climate change

    Endocytosis and intracellular processing of platelet microparticles by brain endothelial cells

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    Platelet-derived microparticles (PMP) bind and modify the phenotype of many cell types including endothelial cells. Recently, we showed that PMP were internalized by human brain endothelial cells (HBEC). Here we intend to better characterize the internalization mechanisms of PMP and their intracellular fate. Confocal microscopy analysis of PKH67-labelled PMP distribution in HBEC showed PMP in early endosome antigen 1 positive endosomes and in LysoTracker-labelled lysosomes, confirming a role for endocytosis in PMP internalization. No fusion of calcein-loaded PMP with HBEC membranes was observed. Quantification of PMP endocytosis using flow cytometry revealed that it was partially inhibited by trypsin digestion of PMP surface proteins and by extracellular Ca2+ chelation by EDTA, suggesting a partial role for receptor-mediated endocytosis in PMP uptake. This endocytosis was independent of endothelial receptors such as intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 and was not increased by tumour necrosis factor stimulation of HBEC. Platelet-derived microparticle internalization was dramatically increased in the presence of decomplemented serum, suggesting a role for PMP opsonin-dependent phagocytosis. Platelet-derived microparticle uptake was greatly diminished by treatment of HBEC with cytochalasin D, an inhibitor of microfilament formation required for both phagocytosis and macropinocytosis, with methyl-β-cyclodextrin that depletes membrane cholesterol needed for macropinocytosis and with amiloride that inhibits the Na+/H+ exchanger involved in macropinocytosis. In conclusion, PMP are taken up by active endocytosis in HBEC, involving mechanisms consistent with both phagocytosis and macropinocytosis. These findings identify new processes by which PMP could modify endothelial cell phenotype and functions. © 2011 The Authors. Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd

    Recent Progress in Neutron Star Theory

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    This review contains chapters discussing: Energy density fluctionals of nuclear matter, Many-body theory of nucleon matter, Hadronic and quark matter, Mixtures of phases in dense matter, Neutron star observations and predictions.Comment: 33 pages +13 figs., Ann. Rev. Nucl. & Part. Science, 200

    Effect of time and day of admission on hospital care quality for patients with chronic obstructive pulmonary disease exacerbation in England and Wales: single cohort study

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    OBJECTIVE: To evaluate if observed increased weekend mortality was associated with poorer quality of care for patients admitted to hospital with chronic obstructive pulmonary disease (COPD) exacerbation. DESIGN: Prospective case ascertainment cohort study. SETTING: 199 acute hospitals in England and Wales, UK. PARTICIPANTS: Consecutive COPD admissions, excluding subsequent readmissions, from 1 February to 30 April 2014 of whom 13 414 cases were entered into the study. MAIN OUTCOMES: Process of care mapped to the National Institute for Health and Care Excellence clinical quality standards, access to specialist respiratory teams and facilities, mortality and length of stay, related to time and day of the week of admission. RESULTS: Mortality was higher for weekend admissions (unadjusted OR 1.20, 95% CI 1.00 to 1.43), and for case-mix adjusted weekend mortality when calculated for admissions Friday morning through to Monday night (adjusted OR 1.19, 95% CI 1.00 to 1.43). Median time to death was 6 days. Some clinical processes were poorer on Mondays and during normal working hours but not weekends or out of hours. Specialist respiratory care was less available and less prompt for Friday and Saturday admissions. Admission to a specialist ward or high dependency unit was less likely on a Saturday or Sunday. CONCLUSIONS: Increased mortality observed in weekend admissions is not easily explained by deficiencies in early clinical guideline care. Further study of out-of-hospital factors, specialty care and deaths later in the admission are required if effective interventions are to be made to reduce variation by day of the week of admission

    Design principles of hair-like structures as biological machines

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    Hair-like structures are prevalent throughout biology and frequently act to sense or alter interactions with an organism's environment. The overall shape of a hair is simple: a long, filamentous object that protrudes from the surface of an organism. This basic design, however, can confer a wide range of functions, owing largely to the flexibility and large surface area that it usually possesses. From this simple structural basis, small changes in geometry, such as diameter, curvature and inter-hair spacing, can have considerable effects on mechanical properties, allowing functions such as mechanosensing, attachment, movement and protection. Here, we explore how passive features of hair-like structures, both individually and within arrays, enable diverse functions across biology. Understanding the relationships between form and function can provide biologists with an appreciation for the constraints and possibilities on hair-like structures. Additionally, such structures have already been used in biomimetic engineering with applications in sensing, water capture and adhesion. By examining hairs as a functional mechanical unit, geometry and arrangement can be rationally designed to generate new engineering devices and ideas

    Observing Brownian motion in vibration-fluidized granular matter

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    At the beginning of last century, Gerlach and Lehrer observed the rotational Brownian motion of a very fine wire immersed in an equilibrium environment, a gas. This simple experiment eventually permitted the full development of one of the most important ideas of equilibrium statistical mechanics: the very complicated many-particle problem of a large number of molecules colliding with the wire, can be represented by two macroscopic parameters only, namely viscosity and the temperature. Can this idea, mathematically developed in the so-called Langevin model and the fluctuation-dissipation theorem be used to describe systems that are far from equilibrium? Here we address the question and reproduce the Gerlach and Lehrer experiment in an archetype non-equilibrium system, by immersing a sensitive torsion oscillator in a granular system of millimetre-size grains, fluidized by strong external vibrations. The vibro-fluidized granular medium is a driven environment, with continuous injection and dissipation of energy, and the immersed oscillator can be seen as analogous to an elastically bound Brownian particle. We show, by measuring the noise and the susceptibility, that the experiment can be treated, in first approximation, with the same formalism as in the equilibrium case, giving experimental access to a ''granular viscosity'' and an ''effective temperature'', however anisotropic and inhomogeneous, and yielding the surprising result that the vibro-fluidized granular matter behaves as a ''thermal'' bath satisfying a fluctuation-dissipation relation

    Gauss-Bonnet Black Holes and Heavy Fermion Metals

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    We consider charged black holes in Einstein-Gauss-Bonnet Gravity with Lifshitz boundary conditions. We find that this class of models can reproduce the anomalous specific heat of condensed matter systems exhibiting non-Fermi-liquid behaviour at low temperatures. We find that the temperature dependence of the Sommerfeld ratio is sensitive to the choice of Gauss-Bonnet coupling parameter for a given value of the Lifshitz scaling parameter. We propose that this class of models is dual to a class of models of non-Fermi-liquid systems proposed by Castro-Neto et.al.Comment: 17 pages, 6 figures, pdfLatex; small corrections to figure 10 in this versio

    Identification of Giardia lamblia DHHC Proteins and the Role of Protein S-palmitoylation in the Encystation Process

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    Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.Fil: Merino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Zamponi, Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Vranych, Cecilia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Touz, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Ropolo, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentin

    Polimiosite : investigação clínica em duas irmãs

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    We present an investigation of a case of polymyositis affecting two sisters of one same parenthood. Their cases have been documented for almost two decades, being investigated by means of a diagnostic protocol which combined clinical findings as well as laboratorial, histopathological and image tests. In both cases, clinical manifestations started in childhood, without signs of involvement of the central and peripheral nervous system. Both patients proved to respond to a therapeutics based on corticosteroids. The degree of relatedness between their parents corroborate the notion that genetic factors may contribute to the development of the disease. ___________________________________________________________________________________________________ RESUMOApresentamos a investigação de dois casos de polimiosite, ocorridos entre irmãs de uma mesma filiação. Seus casos foram documentados ao longo de quase duas décadas, tendo sido diagnosticados utilizando- se de protocolo diagnóstico que combinou achados clínicos, exames laboratoriais, histopatológicos e por imagem. Em ambos os casos, as manifestações clínicas se iniciaram ainda na infância, sendo constatada ausência de acometimento do sistema nervoso central ou periférico. Ambas as pacientes responderam satisfatoriamente a terapia baseada em corticosteróide. O grau de parentesco entre os genitores das pacientes sugere que fatores genéticos podem predispor ao desenvolvimento da doença

    Homozygosity for a missense mutation in the 67 kDa isoform of glutamate decarboxylase in a family with autosomal recessive spastic cerebral palsy: parallels with Stiff-Person Syndrome and other movement disorders

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    Background Cerebral palsy (CP) is an heterogeneous group of neurological disorders of movement and/or posture, with an estimated incidence of 1 in 1000 live births. Non-progressive forms of symmetrical, spastic CP have been identified, which show a Mendelian autosomal recessive pattern of inheritance. We recently described the mapping of a recessive spastic CP locus to a 5 cM chromosomal region located at 2q24-31.1, in rare consanguineous families. Methods Here we present data that refine this locus to a 0.5 cM region, flanked by the microsatellite markers D2S2345 and D2S326. The minimal region contains the candidate gene GAD1, which encodes a glutamate decarboxylase isoform (GAD67), involved in conversion of the amino acid and excitatory neurotransmitter glutamate to the inhibitory neurotransmitter γ-aminobutyric acid (GABA). Results A novel amino acid mis-sense mutation in GAD67 was detected, which segregated with CP in affected individuals. Conclusions This result is interesting because auto-antibodies to GAD67 and the more widely studied GAD65 homologue encoded by the GAD2 gene, are described in patients with Stiff-Person Syndrome (SPS), epilepsy, cerebellar ataxia and Batten disease. Further investigation seems merited of the possibility that variation in the GAD1 sequence, potentially affecting glutamate/GABA ratios, may underlie this form of spastic CP, given the presence of anti-GAD antibodies in SPS and the recognised excitotoxicity of glutamate in various contexts
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