1,671 research outputs found

    Quantum work for sudden quenches in Gaussian random Hamiltonians

    Get PDF
    In the context of nonequilibrium quantum thermodynamics, variables like work behave stochastically. A particular definition of the work probability density function (pdf) for coherent quantum processes allows the verification of the quantum version of the celebrated fluctuation theorems, due to Jarzynski and Crooks, that apply when the system is driven away from an initial equilibrium thermal state. Such a particular pdf depends basically on the details of the initial and final Hamiltonians, on the temperature of the initial thermal state, and on how some external parameter is changed during the coherent process. Using random matrix theory we derive a simple analytic expression that describes the general behavior of the work characteristic function G(u), associated with this particular work pdf for sudden quenches, valid for all the traditional Gaussian ensembles of Hamiltonians matrices. This formula well describes the general behavior of G(u) calculated from single draws of the initial and final Hamiltonians in all ranges of temperatures.Fil: Arrais, Eric G.. Universidade Federal do Rio de Janeiro; BrasilFil: Wisniacki, Diego Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Céleri, Lucas C.. Universidade Federal de Goiás; BrasilFil: De Almeida, Norton G.. Universidade Federal de Goiás; BrasilFil: Roncaglia, Augusto Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Toscano, Fabricio. Universidade Federal do Rio de Janeiro; Brasi

    Kinetic Monte Carlo simulation of molecular processes on supported metal particles

    Get PDF
    A general model is proposed to describe the kinetics of molecular reactions taking place on supported metal particles, which are deformed by the effect of temperature, through kinetic Monte Carlo simulations. The model is applied to the study of the CO oxidation reaction. The effects of adsorbate-adsorbate and adsorbate-metal interactions and of CO and metal atoms diffusion on the reaction window and the overall reaction rate are determined.Fil: Sales, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Gargiulo Almeida, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Zgrablich, G.. Universidad Nacional de San Luis; Argentin

    Computational approaches in antibody-drug conjugate optimization for targeted cancer therapy

    Get PDF
    WOS: 000444683500007PubMed ID: 30068276Cancer has become one of the main leading causes of morbidity and mortality worldwide. One of the critical drawbacks of current cancer therapeutics has been the lack of the target-selectivity, as these drugs should have an effect exclusively on cancer cells while not perturbing healthy ones. In addition, their mechanism of action should be sufficiently fast to avoid the invasion of neighbouring healthy tissues by cancer cells. The use of conventional chemotherapeutic agents and other traditional therapies, such as surgery and radiotherapy, leads to off-target interactions with serious side effects. In this respect, recently developed target-selective Antibody-Drug Conjugates (ADCs) are more effective than traditional therapies, presumably due to their modular structures that combine many chemical properties simultaneously. In particular, ADCs are made up of three different units: a highly selective Monoclonal antibody (Mab) which is developed against a tumour-associated antigen, the payload (cytotoxic agent), and the linker. The latter should be stable in circulation while allowing the release of the cytotoxic agent in target cells. The modular nature of these drugs provides a platform to manipulate and improve selectivity and the toxicity of these molecules independently from each other. This in turn leads to generation of second-and third-generation ADCs, which have been more effective than the previous ones in terms of either selectivity or toxicity or both. Development of ADCs with improved efficacy requires knowledge at the atomic level regarding the structure and dynamics of the molecule. As such, we reviewed all the most recent computational methods used to attain all-atom description of the structure, energetics and dynamics of these systems. In particular, this includes homology modelling, molecular docking and refinement, atomistic and coarse-grained molecular dynamics simulations, principal component and cross-correlation analysis. The full characterization of the structure-activity relationship devoted to ADCs is critical for antibody-drug conjugate research and development.Fundacao para a Ciencia e a Tecnologia (FCT) Investigator programme [IF/00578/2014]; European Social Fund; Programa Operacional Potencial Humano; Marie Sklodowska-Curie Individual Fellowship MSCA-IF-2015 [MEMBRANEPROT 659826]; European Regional Development Fund (ERDF), through the Centro 2020 Regional Operational Programme [CENTRO-01-0145-FEDER-000008]; European Regional Development Fund (ERDF), COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation; Portuguese national funds via FCT [POCI-01-0145-FEDER-007440]; FCT [FCT-SFRH/BPD/97650/2013]; Fundacao para a Ciencia e Tecnologia (FCT), Portugal [UID/Multi/04349/2013]Irina S. Moreira acknowledges support by the Fundacao para a Ciencia e a Tecnologia (FCT) Investigator programme - IF/00578/2014 (co-financed by European Social Fund and Programa Operacional Potencial Humano), and a Marie Sklodowska-Curie Individual Fellowship MSCA-IF-2015 [MEMBRANEPROT 659826]. This work was also financed by the European Regional Development Fund (ERDF), through the Centro 2020 Regional Operational Programme under project CENTRO-01-0145-FEDER-000008: Brain-Health 2020, and through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT, under project POCI-01-0145-FEDER-007440. Rita Melo acknowledges support from the FCT (FCT-SFRH/BPD/97650/2013). This work has been partially supported by the Fundacao para a Ciencia e Tecnologia (FCT), Portugal, through the UID/Multi/04349/2013 project in Centre for Nuclear Sciences and Technologies (C2TN)

    Neonatal near miss: the need for a standard definition and appropriate criteria and the rationale for a prospective surveillance system

    Get PDF
    In Latin American, there is currently a regional action with the main purposes of putting the concept of severe neonatal morbidity in practice and formulating proposals for interventions. A general overview of neonatal health conditions, including morbidity and mortality, is provided to update regional knowledge on the topic. An example of the development and implementation of the concept of maternal near miss is also provided, followed by results from a systematic review covering all previously published studies on Neonatal Near Miss. Finally, some proposals for building a common concept on the topic and for launching a prospective surveillance study are presented. A Neonatal Near Miss is a neonate who had a severe morbidity (organ dysfunction or failure) but who survived this condition within the first 27 days of life. The pragmatic criteria recommended to be used are as follows: birth weight below 1700 g, Apgar score below 7 at 5 minutes of life and gestational age below 33 weeks. As a proxy for organ dysfunction, the following management criteria are also confirmed: parenteral therapeutic antibiotics; nasal continuous positive airway pressure; any intubation during the first 27 days of life; phototherapy within the first 24 h of life; cardiopulmonary resuscitation; the use of vasoactive drugs, anticonvulsants, surfactants, blood products and steroids for refractory hypoglycemia and any surgical procedure. Although this study starts from a regional perspective, this topic is clearly globally relevant. All nations, especially low and middle-income countries, could benefit from the proposed standardization701282082

    3D City Models and urban information: Current issues and perspectives

    Get PDF
    Considering sustainable development of cities implies investigating cities in a holistic way taking into account many interrelations between various urban or environmental issues. 3D city models are increasingly used in different cities and countries for an intended wide range of applications beyond mere visualization. Could these 3D City models be used to integrate urban and environmental knowledge? How could they be improved to fulfill such role? We believe that enriching the semantics of current 3D city models, would extend their functionality and usability; therefore, they could serve as integration platforms of the knowledge related to urban and environmental issues allowing a huge and significant improvement of city sustainable management and development. But which elements need to be added to 3D city models? What are the most efficient ways to realize such improvement / enrichment? How to evaluate the usability of these improved 3D city models? These were the questions tackled by the COST Action TU0801 “Semantic enrichment of 3D city models for sustainable urban development”. This book gathers various materials developed all along the four year of the Action and the significant breakthroughs

    Uroflowmetry in a Large Population of Brazilian Men Submitted to a health check up program and its correlation with ipss and prostate size

    Get PDF
    Purpose: the aim of this study was to assess the uroflowmetry data in a large population of asymptomatic Brazilian men submitted to a health check up program and their correlation to IPSS and prostate size.Materials and Methods: Asymptomatic men underwent a health check-up program between January and December 2012. the inclusion criteria were men between 40 and 70 years, IPSS <= 7, without bladder, prostate, urethral surgery, neurological diseases, urinary tract infection, PSA < 4.0 ng/dL and urinary volume higher than 150 mL. Urological assessment consisted of clinical history, IPSS, digital rectal examination (DRE), prostate specific antigen (PSA), urinalysis, ultrasonography and uroflowmetry.Results: A total of 1041 asymptomatic men were included in this study. the average age was 49 years and average maximum flow rate was 17.4 mL/s. in spite of IPSS and prostate size increase with aging, they had a weak correlation with Q(max) cutoffs (10 mL/s and 15 mL/s). A total of 85 men (8.3%) had more than 60 years, and even in this group, Q(max) was higher than 15 mL/s. Out of 1041 men, 117 had IPSS less than 8 and Q(max) less than 10 mL/s.Conclusions: in asymptomatic men there is a weak correlation between IPSS, prostate size and uroflowmetric data. the establishment of different normal cutoffs seems to be complicated and uroflowmetry data should be interpreted with caution in order to avoid misdiagnosis.Hosp Israelita Albert Einstein, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilWake Forest Univ, Winston Salem, NC 27109 USAUniversidade Federal de São Paulo, São Paulo, BrazilWeb of Scienc

    Measured and modelled cloud condensation nuclei (CCN) concentration in São Paulo, Brazil: the importance of aerosol size-resolved chemical composition on CCN concentration prediction

    Get PDF
    Measurements of cloud condensation nuclei\ud (CCN), aerosol size distribution and non-refractory chemical\ud composition were performed from 16 to 31 October 2012\ud in the São Paulo Metropolitan Area (SPMA), Brazil. CCN\ud measurements were performed at 0.23, 0.45, 0.68, 0.90 and\ud 1.13% water supersaturation and were subsequently compared\ud with the Köhler theory, considering the chemical composition.\ud Real-time chemical composition has been obtained\ud by deploying, for the first time in the SPMA, an aerosol\ud chemical ionization monitor (ACSM). CCN closure analyses\ud were performed considering internal mixtures.\ud Average aerosol composition during the studied period\ud yielded (arithmetic mean ±standard deviation) 4.81±3.05,\ud 3.26±2.10, 0.30±0.27, 0.52±0.32, 0.37±0.21 and\ud 0.04±0.04 μgm−3 for organics, BC, NH4, SO4, NO3\ud and Cl, respectively. Particle number concentration was\ud 12 813±5350 cm−3, with a dominant nucleation mode.\ud CCN concentrations were on average 1090±328 and\ud 3570±1695 cm−3 at SS = 0.23% and SS = 1.13 %, respectively.\ud Results show an increase in aerosol hygroscopicity in the\ud afternoon as a result of aerosol photochemical processing,\ud leading to an enhancement of both organic and inorganic secondary\ud aerosols in the atmosphere, as well as an increase in\ud aerosol average diameter.\ud Considering the bulk composition alone, observed CCN\ud concentrations were substantially overpredicted when compared\ud with the Köhler theory (44.1±47.9% at 0.23% supersaturation and 91.4±40.3% at 1.13% supersaturation).\ud Overall, the impact of composition on the calculated CCN\ud concentration (NCCN) decreases with decreasing supersaturation,\ud partially because using bulk composition introduces\ud less bias for large diameters and lower critical supersaturations,\ud defined as the supersaturation at which the cloud\ud droplet activation will take place. Results suggest that the\ud consideration of only inorganic fraction improves the calculated\ud NCCN.\ud Introducing a size-dependent chemical composition based\ud on filter measurements from previous campaigns has considerably\ud improved simulated values for NCCN (average overprediction\ud error 14.8±38.6% at 0.23% supersaturation and\ud 3.6±21.6% at 1.13% supersaturation). This study provides\ud the first insight on aerosol real-time composition and hygroscopicity\ud at a site strongly impacted by emissions of a unique\ud vehicular fleet due to the extensive biofuel usageFAPES
    corecore