520 research outputs found

    Corrosion resistance in artificial perspiration of Cr-based decorative coatings

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    We aim at developing hexavalent chromium-free coatings for frequently touched decorative parts. Cr(N,O) and multilayered CrN/CrO coatings were deposited by means of reactive magnetron sputtering. All samples presented good adhesion to the substrates enhanced by an epoxy layer designed to enhance PVD coating adhesion. Similar substrates are found in the automotive industry and can be used in appliances where a metallic finish is desired by the consumer. Corrosion behavior was induced, using artificial sweat to simulate long exposure to human touch for 96 h. In potentiodynamic polarization tests, the coatings were revealed to be nobler than the substrate alone. Cr displayed a non-existent passivation region, while gCrN exhibited a quick passivation of the surface and its respective breakdown and several current fluctuations, indicating the occurrence of pitting, which was confirmed by SEM micrography after the corrosion. Regarding EIS results, all films depicted a diminution of impedance modulus (|Z|) after 96 h, which indicates a diminution of corrosion resistance against artificial sweat. Nitride films exhibited the worst anticorrosive features. On the other hand, Cr and CrO exhibited the highest |Z| values. These results are corroborated by low the corrosion rates of both coatings. The equivalent electrical circuit allows us to confirm oxide formation in the outermost layer of the films due to electrolyte/surface interaction, indicating a self-protecting mechanism. Nitride films showed the lowest values and less corrosion resistance, confirming the results obtained in polarization potentiodynamic tests. The coatings developed in this work, namely Cr and CrO, showed a promising corrosion resistance behavior that could endure a lifetime of frequent human touch in various decorative applications either automotive or general appliances.This work was supported by COMPETE 2020 a Portuguese and European Union initiative through the Project POCI-01-0247-FEDER-072607, R&D and production of logos for the automotive industry. This research was sponsored by Norte2020, through European Social Fund (FSE), under the National Doctoral Program in “Surfaces Engineering and Protection”, NORTE-08-5369-FSE-000047. This research is sponsored by national funds through FCT—Fundação para a Ciência e a Tecnologia, under the Ph.D. Research Scholarship with Reference No. 2020.09436.BD. Author Maria José Lima acknowledges FCT for the research contract 2021.00675.CEECIND. This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of Strategic Funding (co-financed via UIDB/00285/2020 and UIDB/04650/2020) and LA/P/0112/2020

    Innovative capacity dynamics: KIBS dimensions

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    The objective of this paper is to explain how the elements of a conceptual model based on KIBS (Knowledge Intensive Business Services) can be applied in an integrated way to assess the innovative capacity of firms in the service sector. The building of the model is based on a bibliometric analysis of the central theme KIBS, in the databases Scopus and ISI Web of Knowledge (Web of Science). We propose a conceptual model, which brings together several dimensions that have not yet been tested in economic sectors. These dimensions are: KIBS, knowledge creation, knowledge transfer, innovation and innovative capacity. The research presents interesting features from the scientific papers analyzed, highlighting gaps that gave origin to the proposed model

    Congenital muscular dystrophy: a clinical report on 17 patients

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    We concur with the idea that congenital muscular dystrophy (CMD) is a distinct clinical entity, and report 17 patients (2 negroes and 15 whites; 12M and 5 F; median age 6 years, range 1 to 24 years) with genetic, clinical, laboratorial, electrophysiological and histochemical studies. All our cases have an inheritance compatible with an autosomal recessive pattern. A decrease in fetal movements was reported by 57% of the mothers, generalized hypotonia at birth was present in 82%, limb girdle and neck weakness, absent or decreased deep tendon reflexes, and limb contractures were present in all. Severe muscular wasting was found in 41%. Calf pseudo-hypertrophy was observed in one patient. A patient was severely mentally retarded and another was borderline. During a 30-month follow-up, the muscle weakness of the majority remained essentially unchanged but the degree of motor activity deteriorated and was proportional to the worsening of the limb contractures. Serum CK levels were normal or increased to a maximum of 8 times. The electromyogram was myopathic in 74%, neurogenic in 13% and normal in 13%. CT scans showed a symmetrical white matter hipodensity in the hemispheres in 8 cases. All but 5 patients were operated upon to release the limb contractures and all were submitted to physical therapy. The contractures recurred in 4 patients submitted to surgery and were probably related to the cessation of physical therapy.Descrevemos 17 pacientes (12m, 5f) com idades que variaram de 1 a 24 anos (mediana 6 anos) com distrofia muscular congênita (DMC), que foram estudados do ponto de vista genético, clínico, laboratorial, eletrofisiológico e anátomo-patológico. A apresentação segundo a herança foi da forma esporádica (76,5%) ou possivelmente autossômica recessiva (23,5%). A diminuição da movimentação fetal intra-uterina foi referida em 57% dos casos, hipotonia neonatal em 82% e retardo no desenvolvimento motor em 88,2%. Fraqueza muscular, diminuição dos reflexos profundos e contraturas articulares estavam presentes em todos os casos. A piora na função motora estava muito relacionada ao aumento ou aparecimento de novas retrações articulares. A CK nunca ultrapassou valores acima de 8 vezes o normal. O ENMG foi de padrão miopático em 73,3%, neuropático em 13,3% e normal em 13,3% dos casos. Aspectos tomográficos com hipodensidade da substância branca subcortical foram vistos em 8 casos. Ao tratamento impôs-se fisioterapia adequada e cirurgia corretiva das deformidades articulares. Novas contraturas desenvolveram-se mais tarde e estavam relacionadas freqüentemente a fisioterapia insuficiente.Escola Paulista de MedicinaUNIFESP, EPMSciEL

    Avaliação fenológica preliminar de cultivares e híbridos de mangueira no semi-árido brasileiro.

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    Este trabalho objetivou avaliar preliminarmente a fenologia de três cultivares comerciais (Ubá, Van Dyke e Tommy Atkins) e quatro novas cultivares híbridas (Alfa, Beta, Lita e Roxa), com potencial para competir com a ‘Tommy Atkins’, no Semi-Árido Brasileiro

    A Discussion on Supersymmetric Cosmic Strings with Gauge-Field Mixing

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    In this paper, following a stream of investigation on supersymmetric gauge theories with cosmic string solutions, we contemplate the possibility of building up a D-and-F term cosmic string by means of a gauge-field mixing in connection with a U(1) x U(1)'-symmetry. The spontaneous break of both gauge symmetry and supersymmetry are thoroughly analysed and the fermion zero-modes are worked out. The role of the gauge-field mixing parameter is elucidated in connection with the string configuration that comes out. As an application of the model presented here, we propose the possibility that the supersimetric cosmic string yield production of fermionic charge carriers that may eject, at their late stages, particles that subsequently decay to produce cosmic rays of ultra-high energy. In our work, it turns out that massive supersymmetric fermionic partners may be produced for a susy breaking scale in the range 10^{11} to 10^{13} GeV, which is compatible with the phenomenology of a gravitino mass at the TeV scale. We also determine the range of the gauge-field mixing parameter, \alpha, in connection with the mass scales of the present model.Comment: 7 pages, no figures, ReVTex format, to appear in New Journal of Physic

    Anharmonic transitions in nearly dry L-cysteine I

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    Two special dynamical transitions of universal character have been recently observed in macromolecules at TD180220T_{D}\sim 180 - 220 K and T100T^{*}\sim 100 K. Despite their relevance, a complete understanding of the nature of these transitions and their consequences for the bio-activity of the macromolecule is still lacking. Our results and analysis concerning the temperature dependence of structural, vibrational and thermodynamical properties of the orthorhombic polymorph of the amino acid L-cysteine (at a hydration level of 3.5%) indicated that the two referred temperatures define the triggering of very simple and specific events that govern all the biochemical interactions of the biomolecule: activation of rigid rotors (T<TT<T^{*}), phonon-phonon interactions with phonons of water dimer (T<T<TDT^{*}<T<T_{D}), and water rotational barriers surpassing (T>TDT>T_{D}).Comment: 4 pages, 4 figures, submitted to Physical Review Letter

    Extração de DNA de folhas adultas de mangífera indica L.

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    O objetivo deste trabalho foi avaliar a concentração e a pureza do DNA extraído de folhas adultas

    Epidemiological situation of bovine brucellosis in the State of São Paulo, Brazil

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    Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Estado de São Paulo. O Estado foi estratificado em sete circuitos produtores de bovinos, e 150 rebanhos com atividade reprodutiva foram aleatoriamente selecionados em cada um deles. No total, foram amostrados 1.073 rebanhos. Foram aletoriamente coletadas amostras de soro de 10 ou 15 fêmeas bovinas com idade ³24 meses, totalizando 8.761 animais. Os soros foram submetidos a um protocolo de testes em série, tendo o teste do antígeno acidificado tamponado como método de triagem e o da fixação de complemento como confirmatório. A prevalência estimada de rebanhos com pelo menos um animal soropositivo foi de 9,7% [7,8-11,6%], enquanto a prevalência estimada de animais soropositivos foi de 3,8% [0,7-6,9%], no Estado. Em cada rebanho foi aplicado um questionário epidemiológico para avaliar o grau de associação de possíveis fatores de risco (odds ratio, OR) com a doença. Propriedades com 87 ou mais bovinos (OR= 2,25) e compra de reprodutores (OR= 1,56) foram as variáveis mais associadas à condição de foco de brucelose. ____________________________________________________________________________________________________________ ARQUIVOA study to characterize the epidemiological situation of bovine brucellosis in the State of São Paulo was carried out. The state was stratified in seven cattle production regions and 150 herds with reproductive activity were randomly selected within each one. A total of 1,073 herds were sampled. In a second stage, 10 or 15 cows older than 24 month age (in herds with <100 cows and herds ≥100 cows, respectively) were bled at random. A total of 8,761 animals were bled. Sera were tested using a serial testing procedure with the Rose Bengal test as the screening method and the Complement Fixation as the confirmatory method. The estimated prevalence of herds with at least one positive animal was 9.7% [7.8-11.6%], whereas the estimated prevalence of positive cattle was 3.8% [0.7-6.9%] in São Paulo State. An epidemiological questionnaire was applied in each farm, allowing the evaluation of the association of selected risk factors with the disease. The characteristics associated with the brucellosis infected herds were farms with more than 87 bovines (OR= 2.25) and introduction of breeding cattle (OR= 1.56)
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