Electrochemical study of the corrosion of Ti- Pd and Ti-6Al-4V electrodes in sodium chloride solutions

The electrochemical behavior of Ti-Pd and Ti-6Al-4V alloys in 0.9% NaCl solution were studied by single triangular potential sweep, potentiodynamic polarization curves, and electrochemical impedance spectroscopy techniques (EIS). The complicated corrosion mechanism can be interpreted as at least one electrodissolution process and the posterior formation of a corrosion films. The results from EIS indicate that, on each electrode, the corrosion layer is formed by different mechanisms.Peer Reviewe

Fluctuations in a superconducting quantum critical point of multi-band metals

In multi-band metals quasi-particles arising from different atomic orbitals coexist at a common Fermi surface. Superconductivity in these materials may appear due to interactions within a band (intra-band) or among the distinct metallic bands (inter-band). Here we consider the suppression of superconductivity in the intra-band case due to hybridization. The fluctuations at the superconducting quantum critical point (SQCP) are obtained calculating the response of the system to a fictitious space and time dependent field, which couples to the superconducting order parameter. The appearance of superconductivity is related to the divergence of a generalized susceptibility. For a single band superconductor this coincides with the \textit{Thouless criterion}. For fixed chemical potential and large hybridization, the superconducting state has many features in common with breached pair superconductivity with unpaired electrons at the Fermi surface. The T=0 phase transition from the superconductor to the normal state is in the universality class of the density-driven Bose-Einstein condensation. For fixed number of particles and in the strong coupling limit, the system still has an instability to the normal sate with increasing hybridization.Comment: 10 pages, 8 figure

Quantum criticality in inter-band superconductors

In fermionic systems with different types of quasi-particles, attractive interactions can give rise to exotic superconducting states, as pair density wave (PDW) superconductivity and breached pairing. In the last years the search for these new types of ground states in cold atom and in metallic systems has been intense. In the case of metals the different quasi-particles may be the up and down spin bands in an external magnetic field or bands arising from distinct atomic orbitals that coexist at a common Fermi surface. These systems present a complex phase diagram as a function of the difference between the Fermi wave-vectors of the different bands. This can be controlled by external means, varying the density in the two-component cold atom system or, in a metal, by applying an external magnetic field or pressure. Here we study the zero temperature instability of the normal system as the Fermi wave-vectors mismatch of the quasi-particles (bands) is reduced and find a second order quantum phase transition to a PDW superconducting state. From the nature of the quantum critical fluctuations close to the superconducting quantum critical point (SQCP), we obtain its dynamic critical exponent. It turns out to be $z=2$ and this allows to fully characterize the SQCP for dimensions $d \ge 2$.Comment: 5 pages, 1 figur

Avaliação da umidade de sementes de cevadilha vacariana.

Resumo.Fernando Flores Cardoso, Daniel Portella Montardo, José Carlos Ferrugem Moraes, Marcos Flávio Silva Borba, Sandro da Silva Camargo, editores técnicos

Avaliação fenológica do jucá (Libidibia ferrea) Martius ex Tul. (Fabaceae).

Libidibia ferrea pertence à familia Fabaceae, nativa do Brasil. Suas propriedades medicinais podem ser usadas para doença dos rins, inflamação, cicatrizante, inflamação, diabetes e diarreia. A fenologia é a atividade que estuda as mudanças que acontecem durante a vida da planta. O objetivo deste trabalho foi avaliar o período de frutificação e floração do jucá, e sua interação com a precipitação pluviométrica. Para as observações fenológicas, foram selecionados 7 indivíduos de jucá. As avaliações foram realizadas diariamente, pela manhã, durante o período de janeiro/2016 a dezembro/2018. O maior pico de dias de floração ocorreu no mês de março com 18 dias e precipitação pluviométrica com 501 mm. Enquanto, os menores números de dias da fenofase ocorreram no período de junho a agosto coincidindo com menores valores de precipitação pluviométrica (1 mm), sendo que, no mês de julho não ocorreu floração. No que diz respeito à frutificação, a maior média do número de dias foi registrado no mês de junho com 17 dias e 171 mm de precipitação pluviométrica e a menor em janeiro e julho com 5 dias e precipitação pluviométrica de 383 e 171 mm, respectivamente. Para uso medicinal das folhas, a coleta deve ser realizada nos meses em que ocorrem os menores números de dias das fenofases

Fenologia reprodutiva da erva cidreira (Verbenaceae).

A espécie Lippia alba, popularmente conhecida como erva cidreira apresenta uma tradição como uso medicinal no país, sendo utilizada para tratamentos de enfermidades como, doenças respiratórias e problemas hepáticos. O objetivo do trabalho foi identificar a frequência de floração e frutificação da erva cidreira relacionando com a precipitação pluviométrica visando indicar a época mais adequada para a coleta e uso medicinal do material vegetal da espécie. Os valores de precipitação pluviométrica foram obtidos da estação meteorológica da Embrapa Amazônia Oriental, utilizando-se a média acumulada mensal para o mesmo período estudado. Foram observados 10 indivíduos da espécie pertencente à coleção da Embrapa Amazônia Oriental, foi registrada a não ocorrência de floração nos meses de abril, maio, junho e julho, e a ocorrência de frutificação apenas nos meses de novembro e dezembro. As maiores médias de número de dias das fenofases registradas coincidem com o período de menor índice de precipitação pluviométrica. Esta espécie apresenta as fenofases influenciadas pela precipitação pluviométrica, devendo a coleta do material vegetal levar em consideração o número de dias de ocorrência das fenofases

Chemical weed control in areas of no-till cassava

O objetivo do trabalho foi avaliar a seletividade para a cultura da mandioca e o comportamento de vários herbicidas, aplicados em pré e pós-emergência, no controle das plantas daninhas Avena sativa, Bidens pilosa, Commelina benghalensis, Raphanus sativus e Sida rhombifolia. O experimento foi conduzido em área de plantio direto, em Araruna, noroeste do Paraná. Embora alguns herbicidas avaliados tenham se destacado em relação ao controle de uma ou mais das espécies de plantas daninhas e outros tenham demonstrado seletividade para a mandioca, os melhores resultados foram obtidos, considerando- se tanto a seletividade quanto a eficácia, com as misturas arnetryne+clornazone (1,50+1,00 kg/ha) e arnetryne+diuron (0,62+0,96 kg/ha), ambas aplicadas em pós-emergência das plantas daninhas e quando a mandioca encontrava-se com 5 a 10% de brotações emergidas. The aim of this work was to evaluate the selectivity of some pre and postemergence herbicides on cassava, as well as their efficiency to control the weeds Avena sativa, Bidens pilosa, Commelina benghalensis, Raphanus sativus and Sida rhombifolia. The field trial was carried out in no-till areas, in Araruna, northwestern Paraná State. Although some herbicides provided outstanding results either in relation to weed control or crop selectivity, when both aspects were taken into consideration, the best results were achieved with arnetryne-i-clornazone (1.50+ 1.00 kg/ha) and ametryne--diuron (0.62+0.96 kg/ha), both applied postemergence of weeds, when 5 to 10% of cassava sprouts had already emerged from the soil

Left ventricular free wall impeding rupture in post-myocardial infarction period diagnosed by myocardial contrast echocardiography: Case report

BACKGROUND: Left ventricular free wall rupture occurs in up to 10% of the in-hospital deaths following myocardial infarction. It is mainly associated with posterolateral myocardial infarction and its antemortem diagnosis is rarely made. Contrast echocardiography has been increasingly used for the evaluation of myocardial perfusion in patients with acute myocardial infarction, with important prognostic implications. In this case, we reported its use for the detection of a mechanical complication following myocardial infarction. CASE PRESENTATION: A 50-year-old man with acute myocardial infarction in the lateral wall underwent myocardial contrast echocardiography for the evaluation of myocardial perfusion in the third day post-infarction. A perfusion defect was detected in lateral and inferior walls as well as the presence of contrast extrusion from the left ventricular cavity into the myocardium, forming a serpiginous duct extending from the endocardium to the epicardial region of the lateral wall, without communication with the pericardial space. Magnetic resonance imaging confirmed the diagnosis of impending rupture of the left ventricular free wall. While waiting for cardiac surgery, patient presented with cardiogenic shock and died. Anatomopathological findings were consistent with acute myocardial infarction in the lateral wall and a left ventricular free wall rupture at the infarct site. CONCLUSION: This case illustrates the early diagnosis of left ventricular free wall rupture by contrast echocardiography. Due to its ability to be performed at bedside this modality of imaging has the potential to identify this catastrophic condition in patients with acute myocardial infarction and help to treat these patients with emergent surgery

Pregnancy outcomes in antiphospholipid antibody positive patients: prospective results from the AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) Clinical Database and Repository ('Registry').

Objectives: To describe the outcomes of pregnancies in antiphospholipid antibody (aPL)-positive patients since the inception of the AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking Registry. Methods: We identified persistently aPL-positive patients recorded as 'pregnant' during prospective follow-up, and defined 'aPL-related outcome' as a composite of: (1) Preterm live delivery (PTLD) at or before 37th week due to pre-eclampsia (PEC), eclampsia, small-for-gestational age (SGA) and/or placental insufficiency (PI); or (2) Otherwise unexplained fetal death after the 10th week of gestation. The primary objective was to describe the characteristics of patients with and without aPL-related composite outcomes based on their first observed pregnancies following registry recruitment. Results: Of the 55 first pregnancies observed after registry recruitment among nulliparous and multiparous participants, 15 (27%) resulted in early pregnancy loss <10 weeks gestation. Of the remaining 40 pregnancies: (1) 26 (65%) resulted in term live delivery (TLD), 4 (10%) in PTLD between 34.0 weeks and 36.6 weeks, 5 (12.5%) in PTLD before 34th week, and 5 (12.5%) in fetal death (two associated with genetic anomalies); and (2) The aPL-related composite outcome occurred in 9 (23%). One of 26 (4%) pregnancies with TLD, 3/4 (75%) with PTLD between 34.0 weeks and 36.6 weeks, and 3/5 (60%) with PTLD before 34th week were complicated with PEC, SGA and/or PI. Fifty of 55 (91%) pregnancies were in lupus anticoagulant positive subjects, as well as all pregnancies with aPL-related composite outcome. Conclusion: In our multicentre, international, aPL-positive cohort, of 55 first pregnancies observed prospectively, 15 (27%) were complicated by early pregnancy loss. Of the remaining 40 pregnancies, composite pregnancy morbidity was observed in 9 (23%) pregnancies