An SOS-regulated operon involved in damage-inducible mutagenesis in Caulobacter crescentus

DNA polymerases of the Y-family, such as Escherichia coli UmuC and DinB, are specialized enzymes induced by the SOS response, which bypass lesions allowing the continuation of DNA replication. umuDC orthologs are absent in Caulobacter crescentus and other bacteria, raising the question about the existence of SOS mutagenesis in these organisms. Here, we report that the C.crescentus dinB ortholog is not involved in damage-induced mutagenesis. However, an operon composed of two hypothetical genes and dnaE2, encoding a second copy of the catalytic subunit of Pol III, is damage inducible in a recA-dependent manner, and is responsible for most ultraviolet (UV) and mitomycin C-induced mutations in C.crescentus. The results demonstrate that the three genes are required for the error-prone processing of DNA lesions. The two hypothetical genes were named imuA and imuB, after inducible mutagenesis. ImuB is similar to proteins of the Y-family of polymerases, and possibly cooperates with DnaE2 in lesion bypass. The mutations arising as a consequence of the activity of the imuAB dnaE2 operon are rather unusual for UV irradiation, including G:C to C:G transversions

Aligned carbon nanotube based sensors for strain sensing applications

This paper presents an aligned carbon nanotube (CNT)-based strain sensor. Vertical aligned carbon nanotubes (VA-CNT), synthesized by chemical vapour deposition (CVD), were knocked down onto polymeric films, in order to obtain a thin 10 × 10 × 0.05 mm CNT patch. Different polymeric substrates, ADEXepoxy, polyethylene terephthalate (PET) and polyimide (PI) were used. The samples’ morphology before and after the knock down process, specifically their alignment, was observed by scanning electron microscopy (SEM). The good quality of the synthesized VA-CNT was assessed by Raman spectroscopy. Furthermore, transmission electron microscopy (TEM) analysis was carried out to determine the average wall number and diameters (inner and outer) of the VA-CNT. A MATLAB software with an adapted Van der Pauw method for anisotropic conductors was developed to determine the electric properties of the obtained samples, which were strained in the transverse (X) and parallel (Y) directions with respect to the CNT alignment. The electric anisotropy, defined as electric resistance ratio between obtained measurements along the X (Rxx) and Y (Ryy) -axes, decreases with deformation increment when the sample was strained in the Y-direction, while it increases when strained in the X-direction. Moreover, the obtained Gauge factor values showed a much sensitive response to deformation, i.e., approximately 47% increase in GF values, when the samples are strained transversely to CNT alignment. These results showed that the piezoresistive CNT/polymeric based sensor produced is suitable for strain sensing applications.This work was funded under the project "IAMAT -Introduction of advanced materials technologies into new product development for the mobility industries", with reference MITP-TB/PFM/0005/2013, under the MIT-Portugal program exclusively financed by FCT - Fundacao para a Ciencia e Tecnologia. This work was carried out in part using the Advanced Electron Microscopy, Imaging and Spectroscopy Facility (TEM) of INL - Iberian Nanotechonology Laboratory

CFRP bioinspirados para melhoria da resistência ao impacto e autossensorização

Os compósitos reforçados com fibras de carbono (CFRP) são cada vez mais usados em aplicações de elevado desempenho devido às excelentes propriedades mecânicas e baixo peso que apresentam. A resistência interlaminar continua, no entanto, a ser uma das maiores limitações do seu desempenho mecânico [1-3]. Recentemente, tem-se vindo a tentar superar o problema aplicando nos CFRP mecanismos semelhantes aos que garantem um elevado desempenho ao impacto em organismos vivos, p.e., o exosqueleto dos artrópodes que apresenta uma estrutura fibrosa laminada helicoidal (Bouligand) à escala micrométrica [4-6]. Sistemas sensoriais estudados em seres vivos também têm inspirado o desenvolvimento de compósitos multifuncionais [7], sendo ainda um desafio a criação de tecnologias de fabrico capazes de replicar estas estruturas/sistemas. Neste trabalho fabricaram-se CFRPs com desempenho mecânico melhorado, usando laminados bioinspirados com fibras orientadas helicoidalmente (tipo Bouligand) e nanotubos de carbono (CNT) como sensores capazes de lhes conferiram multifuncionalidade (monitorização de dano). Produziram-se por infusão por vácuo, usando uma resina epóxída reforçada com fibras contínuas de carbono, placas CFRP (550x180x4 mm) com empilhamentos helicoidal e standard que, para comparação de propriedades, foram sujeitas a ensaios de impacto e de compressão após-impacto. Para garantir a multifuncionalidade, transferiram-se florestas de CNT verticalmente alinhados (VA-CNT) obtidas por deposição química a vapor (CVD) para o laminado. Usaram-se ainda técnicas não-destrutivas (NDT) de ultrassons (C-Scan) na análise da microestrutura e avaliação dos danos produzidos após impacto. Os resultados evidenciam as dificuldades encontradas em fabricar as placas e as melhorias que a integração de estruturas bioinspiradas conferem às características e multifuncionalidade dos compósitosProjeto IAMATinfo:eu-repo/semantics/publishedVersio

Strain sensors based on knocked down carbon nanotubes and bucky papers thin films

Recently, carbon nanotubes (CNTs) thin films have been widely applied in sensing applications due to their piezoresistive response. Furthermore, CNT anisotropic electric properties, due to its alignment, can provide useful information regarding strain direction. We present a comparative study between knocked down vertically aligned CNT based sensor, reported in our previous work [1], and CNT bucky papers (BP) based sensors. For this purpose, commercial multi-wall carbon nanotubes (MWCNTs) were dispersed in two different solvents, dimethylformamide (DMF) and ethanol, vacuum filtrated and dried. From these freestanding BP thin films, 10x10 mm squares were cut off and transferred to polyimide (PI) films. The relative electric resistance response and sensitivity of the strained samples was measured and compared with the knocked down CNT/PI based sensor. Moreover, the morphology of the samples was characterized by scanning electron microscopy (SEM). The results showed a high sensitivity to strain, however knocked down CNT/PI based sensor presented better mechanical performance and an anisotropic behaviour that can be used to infer strain direction.FCT, Programa MIT Portugal, projeto "IAMAT (Introduction of Advanced Materials Technologies into New Product Development for the Mobility Industries

BabA-mediated adherence of pediatric ulcerogenic H. pylori strains to gastric mucins at neutral and acidic pH

Funding This work was supported by the Familjen Erling-Perssons Stiftelse;Fundação para a Ciência e a Tecnologia [FCTPTDC/BIM-MEC/1051/2012];Swedish research council [521-2011-2370];Swedish research council [621-2014-4361]; Swedish cancer society;Åke Wibergs ;Ragnar Söderbergs stiftelse;Stiftelserna Wilhelm och Martina Lundgrens;Svenska Forskningsrådet Formas [221-2013-590];Svenska Forskningsrådet Formas [221-2011-1036].Helicobacter pylori infection can result in non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), adenocarcinoma, and gastric lymphoma. H. pylori reside within the gastric mucus layer, mainly composed of mucins carrying an array of glycan structures that can serve as bacterial adhesion epitopes. The aim of the present study was to characterize the binding ability, adhesion modes, and growth of H. pylori strains from pediatric patients with NUD and PUD to gastric mucins. Our results showed an increased adhesion capacity of pediatric PUD H. pylori strains to human and rhesus monkey gastric mucins compared to the NUD strains both at neutral and acidic pH, regardless if the mucins were positive for Lewis b (Leb), Sialyl-Lewis x (SLex) or LacdiNAc. In addition to babA positive strains being more common among PUD associated strains, H. pylori babA positive strains bound more avidly to gastric mucins than NUD babA positive strains at acidic pH. Binding to Leb was higher among babA positive PUD H. pylori strains compared to NUD strains at neutral, but not acidic, pH. PUD derived babA-knockout mutants had attenuated binding to mucins and Leb at acidic and neutral pH, and to SLex and DNA at acidic pH. The results highlight the role of BabA-mediated adherence of pediatric ulcerogenic H. pylori strains, and points to a role for BabA in adhesion to charged structures at acidic pH, separate from its specific blood group binding activity.publishersversionpublishe

Validação brasileira do Instrumento de Qualidade de Vida/espiritualidade, religião e crenças pessoais

OBJETIVO: Analisar propriedades psicométricas do Instrumento de Qualidade de Vida da Organização Mundial da Saúde - Módulo Espiritualidade, Religiosidade e Crenças Pessoais (WHOQOL-SRPB). MÉTODOS: O WHOQOL-SRPB, a Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), o WHOQOL-Breve e o BDI foram consecutivamente aplicados em amostra de conveniência de 404 pacientes e funcionários de hospital universitário e funcionários de universidade, em Porto Alegre, RS, entre 2006 e 2009. A amostra foi estratificada por sexo, idade, estado de saúde e religião/crença. O reteste dos dois primeiros instrumentos foi realizado com 54 participantes. Análises fatoriais exploratórias do WHOQOL-SRPB pelo método dos componentes principais foram realizadas sem delimitar o número de fatores, solicitando oito fatores e em conjunto com os itens do WHOQOL-Breve. RESULTADOS: O WHOQOL-SRPB em português brasileiro (Domínio SRPB-Geral) apresentou validade de construto, com validade discriminativa entre crentes de não-crentes (t = 7,40; p = 0,0001); validade relacionada ao critério concorrente, discriminando deprimidos de não-deprimidos (t = 5,03; p = 0,0001); validade convergente com o WHOQOL-Breve (com físico r = 0,18; psicológico r = 0,46; social r = 0,35; ambiental r = 0,29; global r = 0,23; p = 0,0001) e com o Domínio SRPB do WHOQOL-100 (r = 0,78; p = 0,0001); e validade convergente/discriminante com a Escala CRE-Breve (com CREpositivo r = 0,64; p = 0,0001/CREnegativo r = -0,03; p = 0,554). Observou-se excelente fidedignidade teste-reteste (t = 0,74; p = 0,463) e consistência interna (α = 0,96; correlação intrafatorial 0,87 >; r >; 0,60, p = 0,0001). As análises fatoriais exploratórias realizadas corroboraram a estrutura de oito fatores do estudo multicêntrico do WHOQOL-SRPB. CONCLUSÕES: O WHOQOL-SRPB em português brasileiro apresentou boas qualidades psicométricas e uso válido e fidedigno para uso no Brasil. Sugerem-se novos estudos com populações específicas, como diferentes religiões, grupos culturais e/ou doenças.OBJECTIVE: To analyze the psychometric properties of the World Health Organization's Quality of Life Instrument - Spirituality, Religion and Personal Beliefs module (WHOQOL-SRPB). METHODS: The WHOQOL-SRPB, the Brief Spiritual/Religious Coping Scale (Brief-SRCOPE Scale), the WHOQOL-BREF and the Beck Depression Inventory (BDI) were consecutively applied in a convenience sample of 404 patients and workers of a university hospital and workers of a university, in the city of Porto Alegre, Southern Brazil, between 2006 and 2009. The sample was stratified by sex, age, health status and religion/belief. The retest of the two first instruments was conducted with 54 participants. Exploratory factorial analyses of the WHOQOL-SRPB with the method of main components were performed, without limiting the number of factors, and requiring eight factors concomitantly with the WHOQOL-BREF items. RESULTS: The Brazilian Portuguese version of the WHOQOL-SRPB (General SRPB-Domain) showed construct validity, with a discriminatory validity between believers and non-believers (t = 7.40; p = 0.0001); concurrent criterion-related validity, distinguishing depressed individuals from non-depressed ones (t = 5.03; p = 0.0001); convergent validity with the WHOQOL-BREF (physical r = 0.18; psychological r = 0.46; social r = 0.35; environmental r = 0.29; global r = 0.23; p = 0.0001) and with the SRPB-Domain of the WHOQOL-100 (r = 0.78; p = 0.0001); and convergent/discriminatory validity with the brief SRCOPE Scale (with positive SRCOPE r = 0.64; p = 0.0001/negative SRCOPE r = -0.03; p = 0.554). Excellent test-retest reliability (t = 0.74; p = 0.463) and internal consistency (α = 0.96; intrafactorial correlation 0.87 >; r >; 0.60; p = 0.0001) were observed. The exploratory factorial analyses performed corroborated the eight-factor structure of the WHOQOL-SRPB multicenter study. CONCLUSIONS: The Brazilian Portuguese version of the WHOQOL-SRPB showed good psychometric qualities and use valid and reliable in Brazil. It is suggested that new studies be conducted with specific populations, such as different religions, cultural groups and/or diseases.OBJETIVO: Analizar propiedades psicométricas del Instrumento de Calidad de Vida de la OMS - Módulo Espiritualidad, Religiosidad y Creencias Personales (WHOQOL-SRPB). MÉTODOS: El WHOQOL-SRPB, la Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), el WHOQOL-Breve y el BDI fueron consecutivamente aplicados en muestra de conveniencia de 404 pacientes y funcionarios de hospital universitario y funcionarios de universidad, en Porto Alegre, Sur de Brasil, entre 2006 y 2009. La muestra fue estratificada por sexo, edad, estado de salud y religión/creencia. La reevaluación de los dos primeros instrumentos fue realizada por 54 participantes. Análisis factoriales exploratorias del WHOQOL-SRPB por el método de los componentes principales fueron realizadas, sin delimitar el número de factores, solicitando ocho factores y en conjunto con los itens del WHOQOL-Breve. RESULTADOS: El WHOQOL-SRPB en portugués-brasileño (Dominio SRPB-General) presentó validez de constructo, con validez discriminativa entre creyentes de no creyentes (t=7,40; p=0,0001); validez relacionada con el criterio concurrente, discriminando deprimidos de no deprimidos (t=5,03; p=0,0001); validez convergente con el WHOQOL-Breve (con físico r=0,18; psicológico r=0,46; social r=0,35; ambiental r=0,29; global r=0,23; p=0,0001) y con el Dominio-SRPB del WHOQOL-100 (r=0,78; p=0,0001); y validez convergente/discriminante con la Escala CRE-Breve (con CRE positivo r=0,64; p=0,0001/CRE negativo r=-0,03; p=0,554). Se observó excelente fidedignidad test-retest (t=0,74; p=0,463) y consistencia interna (α=0,96; correlación intrafactorial 0,87>;r>;0,60, p=0,0001). Los análisis factoriales exploratorios realizados corroboran la estructura de ocho factores de estudio multicéntrico del WHOQOL-SRPB. CONCLUSIONES: El WHOQOL-SRPB en portugués-brasileño presentó buenas cualidades psicométricas, siendo válido y fidedigno para uso en Brasil. Se sugieren nuevos estudios con poblaciones específicas, como diferentes religiones, grupos culturales y/o enfermedades

Engineering single-atom Fe-N active sites on hollow carbon spheres for oxygen reduction reaction

Seeking alternatives to noble metals-based electrocatalysts for oxygen reduction reaction (ORR), hollow carbon spheres (CSs) were finely tuned with stable single-atom Fe-N species through a synthesis methodology requiring only earth-abundant metal precursors. CSs with different sizes were synthesized by sol-gel polycondensation of resorcinol with formaldehyde over silica nanoparticles, followed by thermal annealing and silica etching. A catalyst screening revealed the positive impact of both the hollow core and structural defects of the CSs for ORR. Single-atom Fe-N active sites were introduced on the best performing CSs through simultaneous incorporation of iron and nitrogen precursors, and glucose. A significant enhancement in ORR activity was observed despite the small iron load introduced (0.12 wt%). ORR performance indicators, advanced characterization, and molecular simulation studies revealed nitrogen's crucial role in anchoring individual iron atoms and modulating the charge density nearby the active sites (increase of 80 mV in the half-wave potential). Adding glucose as a chelating agent enhances the metal-heteroatom coordination and subsequent dispersion of iron, accounting for an increase of 20 mV in the half-wave potential, an average of electrons transferred as high as 3.9 (at 0.4 V vs. RHE), and higher stability (99%) than that of a platinum-based (20 wt%) electrocatalyst (92%).11 página

Influence of body composition on gait Kinetics throughout pregnancy and postpartum period

Pregnancy leads to several changes in body composition and morphology of women. It is not clear whether the biomechanical changes occurring in this period are due exclusively to body composition and size or to other physiological factors. The purpose was to quantify the morphology and body composition of women throughout pregnancy and in the postpartum period and identify the contribution of these parameters on the lower limb joints kinetic during gait. Eleven women were assessed longitudinally, regarding anthropometric, body composition, and kinetic parameters of gait. Body composition and body dimensions showed a significant increase during pregnancy and a decrease in the postpartum period. In the postpartum period, body composition was similar to the 1st trimester, except for triceps skinfold, total calf area, and body mass index, with higher results than at the beginning of pregnancy. Regression models were developed to predict women’s internal loading through anthropometric variables. Four models include variables associated with the amount of fat; four models include variables related to overall body weight; three models include fat-free mass; one model includes the shape of the trunk as a predictor variable. Changes in maternal body composition and morphology largely determine kinetic dynamics of the joints in pregnant women

O157:H7 Shiga Toxin-Producing Escherichia coli Strains Associated with Sporadic Cases of Diarrhea in São Paulo, Brazil

Inst Adolfo Lutz Registro, Sao Paulo, BrazilLab Anal Clin Dr Joao Antonio Vozza, Campinas, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Sao Paulo, BrazilWeb of Scienc