1,383 research outputs found

    The influence of chemical reaction conditions upon poly(styrene‐methyl methacrylate‐acrylic acid) synthesis: Variations in nanoparticle size, colour and deposition methods

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    Monodisperse latex nanospheres of poly(styrene‐methyl methacrylate‐acrylic acid) with different sizes were synthetised by soap‐free emulsion copolymerisation and applied onto polyamide 6,6 fabrics by two methods, ie, gravitational sedimentation and dip‐drawing. Different‐sized nanospheres were synthetised by varying temperature and stirring velocity as reaction parameters. Scanning electron microscopy and scanning transmission electron microscopy were used to evaluate nanosphere sizes and deposition structures. The results showed two different nanosphere structural arrangements on the fabric surface, a hexagonal packed centre structure in the even surfaces and a square arrangement in the out‐of‐plane surfaces. Different colours were observed according to particle size, namely, violet (ca. 170 nm), blue (ca. 190 nm), green (ca. 210 nm), yellow (ca. 230 nm) and red (ca. 250 nm). An iridescence effect was also observed, displaying different colours at different observation angles. By controlling the size of the nanospheres it was possible to obtain different, brilliant and iridescent colours. Using different nanosphere sizes it was possible to obtain different interplanar distances and to control the light scattering in the crystalline lattice planes, obtaining Bragg diffraction patterns.Fundação para a Ciência e a Tecnologia, Grant/Award Number: IF/00071/2015, PTDC/CTM-TEX/28295/2017 , SFRH/BD/145269/2019 and UID/CTM/00264/2019; European Regional Development funds (FEDER); Competitiveness and Internationalization Operational Program (POCI)—COMPETE, Grant/Award Number: POCI-01-0145-FEDER-0071

    Boosting search by rare events

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    Randomized search algorithms for hard combinatorial problems exhibit a large variability of performances. We study the different types of rare events which occur in such out-of-equilibrium stochastic processes and we show how they cooperate in determining the final distribution of running times. As a byproduct of our analysis we show how search algorithms are optimized by random restarts.Comment: 4 pages, 3 eps figures. References update

    Isolamento de Helicobacter pullorum de carne de frango: características de um patogénio emergente de origem alimentar

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    Objetivo: Este estudo apresenta a primeira descrição do isolamento de H. pullorum em amostras de carne de frango crua, revelando o importante papel da metodologia de Sequenciação Total do Genoma para a correta identificação e caracterização das estirpes isolada

    Identificação molecular de Bartonella henselae em paciente com SIDA soronegativo para doença da arranhadura do gato no Rio de Janeiro, Brasil

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    Bartonella henselae is associated with a wide spectrum of clinical manifestations, including cat scratch disease, endocarditis and meningoencephalitis, in immunocompetent and immunocompromised patients. We report the first molecularly confirmed case of B. henselae infection in an AIDS patient in state of Rio de Janeiro, Brazil. Although DNA sequence of B. henselae has been detected by polymerase chain reaction in a lymph node biopsy, acute and convalescent sera were nonreactive.Bartonella henselae está associada a um amplo espectro de manifestações clínicas, incluindo a doença da arranhadura de gato, endocardite, e meningoencefalite, em pacientes imunocompetentes e imunocomprometidos. Relatamos o primeiro caso confirmado por método molecular de B. henselae em um paciente com SIDA no estado do Rio de Janeiro, Brasil. Apesar da sequência de DNA de B. henselae ser detectada pela reação em cadeia da polimerase em uma biópsia do linfonodo, soros das fases aguda e convalescente foram não reativos

    Being open, feeling safe and getting creative: The role of team mean openness to experience in the emergence of team psychological safety and team creativity

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    Although the effects of openness to experience (OTE) on individual creativity are well-established, research on how such effects unfold in a team context is scarce. Drawing on theories of group norms and uncertainty reduction, we argue that team mean OTE leads to a climate of team psychological safety which, in turn, facilitates team creativity. We test our hypothesis over three independent studies, the first comprising 35 business student project teams, the second based on 28 professional teams from the automotive industry, both conducted in the United Kingdom, and the third comprising 24 healthcare teams in Portugal. As predicted, across all three studies, team mean OTE was positively associated with team creativity via the affective emergent state of team psychological safety. Furthermore, the mediating role of team psychological safety remained significant even when accounting for team OTE variance, alternative motivational and cognitive emergent states, namely team promotion focus (studies 1 and 2) and team exploration climate (study 3), as well as empowering leadership (study 3). Finally, in study 3, we examined the differential impact of the two major facets of OTE, intellect, and openness, and found that intellect, but not openness, was responsible for driving the indirect effects. Further analysis did not support alternative perspectives concerning team OTE variance or the interaction between mean and variance. Our findings not only contribute to theoretical understanding regarding the relationship between team personality composition, specifically OTE, and team creativity but also provide much-needed insight into how such effects unfold. We delineate several practical implications for team design and development

    Saúde perinatal: metodologia e características da população estudada

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    OBJECTIVE: To describe the methodological procedures and some sociodemographic and medical care characteristics of the population studied in a research project on perinatal health developed in the Ribeirão Preto county, SP, in 1994, in order to make historical comparisons with the indicators of mother-child health of a similar study conducted 15 years before in the same municipality. MATERIAL AND METHOD: All the hospital births that occurred in Ribeirão Preto from June 1978 to May 1979 were studied by interviewing the mothers and obtaining data about maternal and paternal habits, social situation of the family, medical care during pregnancy and delivery, duration of pregnancy, and anthropometric and mortality data about the newborn children. A new study was conducted in 1994 using the same methodology to collect data about a sample of 1/3 of the births that had occurred in the municipality in that year (all the hospital births observed during a period of 4 months), and also about the mortality of this group up to one year after the termination of birth data collection. The interviews were held after delivery and infant weight and length were measured immediately after birth. Infant mortality was evaluated by surveying the data referring to all deaths of infants born during the year of the study and up to 1 year after its termination. The data were obtained from the Municipal Health Secretariat to which copies of all death certificates emitted in the registry offices of the county are sent obligatorily. RESULTS: An investigation was made into 3,663 births, 3,579 of which were singletons; of these, 2,846 were from the municipality. Comparison with the data obtained in the previous study showed an increase in the frequency of some indicators such as adolescent mothers, prematurity, low birth weight and cesarian section; on the other hand, there was a 50% decrease in the mortality rate and its components.OBJETIVO: Descrever os procedimentos metodológicos e algumas características demógrafo-sociais e da atenção médica da população estudada em um projeto de pesquisa em saúde perinatal realizado no Município de Ribeirão Preto, SP, Brasil, em 1994, visando a realizar comparações históricas com indicadores de saúde materno-infantil. MATERIAL E MÉTODO: Entre junho de 1978 e maio de 1979 foram estudados todos os nascimentos hospitalares de Ribeirão Preto através de entrevistas com as mães, onde eram obtidos dados sobre hábitos maternos e paternos, situação social da família, atenção médica à gestação e parto, duração da gestação e dados antropométricos e de mortalidade dos recém-nascidos. Em 1994 foi realizado novo estudo com metodologia semelhante, sendo coletados dados de uma amostra de 1/3 dos nascimentos ocorridos no município naquele ano (todos os nascimentos hospitalares observados num período de 4 meses), e também a mortalidade desse grupo até um ano após o encerramento da coleta de dados do nascimento. As entrevistas eram realizadas após o parto, e o peso e comprimento da criança eram aferidos logo após o nascimento. A mortalidade infantil foi avaliada através do levantamento de todos os óbitos de crianças nascidas durante o período do projeto até um ano após seu encerramento. RESULTADOS: Foram analisados 3.663 nascimentos, dos quais 3.579 eram nascimentos únicos; destes, 2.846 eram procedentes do município estudado. Quando comparados com os dados do estudo anterior, verifica-se que houve aumento da freqüência de alguns indicadores como mães adolescentes, prematuridade, baixo peso ao nascer e parto cesáreo; por outro lado, houve diminuição da metade da mortalidade infantil e seus componentes

    Mechanisms of vesicular stomatitis virus inactivation by protoporphyrin ix, zinc- protoporphyrin ix, and mesoporphyrin ix

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    © 2017 American Society for Microbiology. All Rights Reserved.Virus resistance to antiviral therapies is an increasing concern that makes the development of broad-spectrum antiviral drugs urgent. Targeting of the viral envelope, a component shared by a large number of viruses, emerges as a promising strategy to overcome this problem. Natural and synthetic porphyrins are good candidates for antiviral development due to their relative hydrophobicity and pro-oxidant character. In the present work, we characterized the antiviral activities of protoprophyrin IX (PPIX), Zn-protoporphyrin IX (ZnPPIX), and mesoporphyrin IX (MPIX) against vesicular stomatitis virus (VSV) and evaluated the mechanisms involved in this activity. Treatment of VSV with PPIX, ZnPPIX, and MPIX promoted dose-dependent virus inactivation, which was potentiated by porphyrin photoactivation. All three porphyrins inserted into lipid vesicles and disturbed the viral membrane organization. In addition, the porphyrins also affected viral proteins, inducing VSV glycoprotein cross-linking, which was enhanced by porphyrin photoactivation. Virus incubation with sodium azide and α-tocopherol partially protected VSV from inactivation by porphyrins, suggesting that singlet oxygen (1O2) was the main reactive oxygen species produced by photoactivation of these molecules. Furthermore, 1O2 was detected by 9,10-dimethylanthracene oxidation in photoactivated porphyrin samples, reinforcing this hypothesis. These results reveal the potential therapeutic application of PPIX, ZnPPIX, and MPIX as good models for broad antiviral drug design.Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ; Brazil; grant number E-26/201.167/2014), the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq; Brazil; grant number 306669/2013-7), the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES; Brazil; grant number CsF 171/2012), the Fundacao para a Ciencia e Tecnologia-Ministério da Educação e Ciência (FCT-MEC; Portugal; project HIVERA/0002/2013), and Marie Skłodowska-Curie Actions (MSCA; European Commission project INPACT 644167). C.C.-O. acknowledges a Science without Borders postdoctoral fellowship from CAPES (171/2012), and J.M.F. acknowledges an FCT-MEC Ph.D. fellowship (SFRH/BD/70423/2010)info:eu-repo/semantics/publishedVersio
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