Study of pitting corrosion resistance of austenitic stainless steels: influence of the manganese addition in solid solution

Este documento apresenta os resultados de uma pesquisa sobre a influencia do Mn em solução sólida sobre a resistência à corrosão por pite de aços inoxidáveis austeníticos, um denominado 17Cr6Mn5Ni e um aço comercial UNS S304L utilizado como material de referencia. Foram usadas soluções electrolíticas de 0,6M NaCl em três diferentes condições de concentração de oxigênio (solução desaerada, naturalmente aerada e aerada artificialmente). O desempenho de cada condição foi medido a través de testes de polarização potenciodinâmica e mediante exames metalográficos. Determinaram-se os potencias de corrosão (Ecorr) e de pite (Ep). A concentração de oxigênio na solução eletrolítica influenciou o parâmetro Ecorr, mas não o Ep.O manganês em solução sólida beneficia a absorção de íons Cl- em aços inoxidáveis austeníticos, exercendo, portanto um efeito negativo quanto à resistência à corrosão por pite. Através de dados experimentais de energia livre de Gibbs de formação de compostos (∆G°) e da teoria de absorção competitiva, foi proposto um mecanismo para explicar este fenômeno.In this research are shown the results about the study of the influence of manganese in solid solution on the pitting corrosión resistance of austenitic stainless steels, a steel is referred to as 17Cr6Mn5Ni and the UNS S304L steel as benchmarking material. Electrolytic solution containing 0.6M NaCl in three different oxygen concentration were used (aerated, non aerated and naturally aerated). The behavior of each condition was measured through potentiodynamic polarization tests and metallographic examinations. The values of corrosion potential (Ecorr) and pitting potential (Ep) were determined. The oxygen concentration of the electrolytic solution influenced the Ecorr but not the Ep parameter.Manganese in solid solution benefits the Cl- ions absorption in austenitic stainless steels. Therefore, causes negative effect on pitting corrosion resistance. A mechanism was proposed through the standard Gibbs free energy of formation of compounds (∆G°) data, and through the competitive absorption theory.Este documento presenta los resultados de una investigación sobre la influencia del Mn en solución sólida sobre la resistencia a la corrosión por picadura de dos aceros inoxidables austeníticos, uno denominado 17 Cr 6Mn 5Ni y un acero comercial UNS S304L utilizado como material de referencia. Fueron usadas soluciones electrolíticas de 0,6M NaCl en tres diferentes condiciones de concentración de oxígeno (solución desaireada, naturalmente aireada y aireada artificialmente). El desempeño de cada condición fue medido a través de ensayos de polarización potenciodinámica y mediante exámenes metalográficos. Se determinaron los potenciales de corrosión (Ecorr) y de picadura (Ep). La concentración de oxígeno en la solución electrolítica influenció el parámetro Ecorr, pero no el Ep.El manganeso en solución sólida beneficia la absorción de iones Cl- en aceros inoxidables austeníticos, ejerciendo por tanto un efecto negativo en cuanto a resistencia a corrosión por picadura. A través de datos experimentales de energía libre de Gibbs de formación de compuestos (∆G°) y de la teoría de absorción competitiva, fue propuesto un mecanismo para explicar este fenómeno

Study of pitting corrosion resistance of austenitic stainless steels: influence of the manganese addition in solid solution

Este documento apresenta os resultados de uma pesquisa sobre a influencia do Mn em solução sólida sobre a resistência à corrosão por pite de aços inoxidáveis austeníticos, um denominado 17Cr6Mn5Ni e um aço comercial UNS S304L utilizado como material de referencia. Foram usadas soluções electrolíticas de 0,6M NaCl em três diferentes condições de concentração de oxigênio (solução desaerada, naturalmente aerada e aerada artificialmente). O desempenho de cada condição foi medido a través de testes de polarização potenciodinâmica e mediante exames metalográficos. Determinaram-se os potencias de corrosão (Ecorr) e de pite (Ep). A concentração de oxigênio na solução eletrolítica influenciou o parâmetro Ecorr, mas não o Ep.O manganês em solução sólida beneficia a absorção de íons Cl- em aços inoxidáveis austeníticos, exercendo, portanto um efeito negativo quanto à resistência à corrosão por pite. Através de dados experimentais de energia livre de Gibbs de formação de compostos (∆G°) e da teoria de absorção competitiva, foi proposto um mecanismo para explicar este fenômeno.In this research are shown the results about the study of the influence of manganese in solid solution on the pitting corrosión resistance of austenitic stainless steels, a steel is referred to as 17Cr6Mn5Ni and the UNS S304L steel as benchmarking material. Electrolytic solution containing 0.6M NaCl in three different oxygen concentration were used (aerated, non aerated and naturally aerated). The behavior of each condition was measured through potentiodynamic polarization tests and metallographic examinations. The values of corrosion potential (Ecorr) and pitting potential (Ep) were determined. The oxygen concentration of the electrolytic solution influenced the Ecorr but not the Ep parameter.Manganese in solid solution benefits the Cl- ions absorption in austenitic stainless steels. Therefore, causes negative effect on pitting corrosion resistance. A mechanism was proposed through the standard Gibbs free energy of formation of compounds (∆G°) data, and through the competitive absorption theory.Este documento presenta los resultados de una investigación sobre la influencia del Mn en solución sólida sobre la resistencia a la corrosión por picadura de dos aceros inoxidables austeníticos, uno denominado 17 Cr 6Mn 5Ni y un acero comercial UNS S304L utilizado como material de referencia. Fueron usadas soluciones electrolíticas de 0,6M NaCl en tres diferentes condiciones de concentración de oxígeno (solución desaireada, naturalmente aireada y aireada artificialmente). El desempeño de cada condición fue medido a través de ensayos de polarización potenciodinámica y mediante exámenes metalográficos. Se determinaron los potenciales de corrosión (Ecorr) y de picadura (Ep). La concentración de oxígeno en la solución electrolítica influenció el parámetro Ecorr, pero no el Ep.El manganeso en solución sólida beneficia la absorción de iones Cl- en aceros inoxidables austeníticos, ejerciendo por tanto un efecto negativo en cuanto a resistencia a corrosión por picadura. A través de datos experimentales de energía libre de Gibbs de formación de compuestos (∆G°) y de la teoría de absorción competitiva, fue propuesto un mecanismo para explicar este fenómeno

Estimulação cerebral profunda na Doença de Parkinson: evidências de estudos de longa duração

A Doença de Parkinson (DP) é uma condição neurodegenerativa crônica que afeta principalmente idosos, mas pode ocorrer em adultos jovens. É a segunda doença neurodegenerativa mais comum, após o Alzheimer. A DP afeta 1% dos indivíduos acima de 60 anos em países industrializados. Sua causa envolve fatores genéticos e ambientais, como exposição a pesticidas e envelhecimento. A Estimulação Cerebral Profunda (DBS) é um tratamento que simula lesões cerebrais, melhorando sintomas motores e não motores. O presente estudo tem como objetivo analisar evidências de estudos sobre a eficácia da DBS no tratamento da DP. Trata-se de uma revisão sistemática de estudos quantitativos que utiliza as bases de dados PubMed (Medline), Cochrane Library e Scientific Electronic Library Online (SciELO) para selecionar artigos científicos. Os estudos incluídos abrangem o período de 2013 a 2023 e estão em inglês, abordando a DBS no tratamento da DP. A DBS melhora diversos sintomas motores e não motores, resultando em uma melhor qualidade de vida para os pacientes. Tais benefícios são sustentados mesmo em estágios avançados da Doença de Parkinson, a qual consiste em fornecer pulsos de corrente elétrica a áreas cerebrais profundas através de eletrodos implantados cirurgicamente, geralmente quando a terapia medicamentosa já não é eficaz. Em um estudo com 82 pacientes, a terapia com DBS resultou em uma redução de ± 52% nos sintomas motores do UPDRS sob medicação antes da cirurgia. A melhora nos sintomas motores com a estimulação, em comparação com a ausência de estimulação e medicação, foi de ± 61% no primeiro ano e ± 39% de 8 a 15 anos após a cirurgia (antes da reprogramação). A medicação foi reduzida em ± 55% após 1 ano e ± 44% após 8 a 15 anos, com a maioria dos pacientes mostrando melhorias após a reprogramação. De acordo com as literaturas analisadas, a DBS é uma terapia eficaz para a DP. Enfatiza-se a importância da inovação contínua e dos novos estudos para explorar as facetas não investigadas desse campo. Com a abordagem dos aspectos clínicos, cirúrgicos, tecnológicos e científicos, destacam-se os benefícios, limitações e desafios a serem superados. Ademais, inovações tecnológicas na DBS, como a estimulação direcional, adaptativa e a telemedicina estão sendo exploradas. Em suma, este artigo fornece evidências sobre os benefícios da DBS na DP, ressaltando a necessidade de pesquisas adicionais para otimizar tal intervenção terapêutica e melhorar a qualidade de vida dos pacientes

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Estudio de la resistencia a la corrosión por picadura de aceros inoxidables austeníticos: influencia de la adición de manganeso en solución sólida

Este documento presenta los resultados de una investigación sobre la influencia del Mn en solución sólida sobre la resistencia a la corrosión por picadura de dos aceros inoxidables austeníticos, uno denominado 17Cr6Mn5Ni y un acero comercial UNS S304L utilizado como material de referencia. Fueron usadas soluciones electrolíticas de 0,6M NaCl en tres diferentes condiciones de concentración de oxígeno (solución desaireada, naturalmente aireada y aireada artificialmente). El desempeño de cada condición fue medido a través de ensayos de polarización potenciodinámica y mediante exámenes metalográficos. Se determinaron los potenciales de corrosión (Ecorr) y de picadura (Ep). La concentración de oxígeno en la solución electrolítica influenció el parámetro Ecorr, pero no el Ep.El manganeso en solución sólida beneficia la absorción de iones Cl- en aceros inoxidables austeníticos, ejerciendo por tanto un efecto negativo en cuanto a resistencia a corrosión por picadura. A través de datos experimentales de energía libre de Gibbs de formación de compuestos (∆G°) y de la teoría de absorción competitiva, fue propuesto un mecanismo para explicar este fenómeno

Screening for decreased glomerular filtration rate and associated risk factors in a cohort of HIV-infected patients in a middle-income country

Submitted by Rodrigo Senorans ([email protected]) on 2015-05-08T17:14:14Z No. of bitstreams: 1 Screening for decreased glomerular filtration rate and associated risk factors in a cohort of HIV-infected patients in a middle-income country.pdf: 183300 bytes, checksum: c4e1fabfd912ba83a08f4407a34c0900 (MD5)Approved for entry into archive by Anderson Silva ([email protected]) on 2015-05-11T12:42:53Z (GMT) No. of bitstreams: 1 Screening for decreased glomerular filtration rate and associated risk factors in a cohort of HIV-infected patients in a middle-income country.pdf: 183300 bytes, checksum: c4e1fabfd912ba83a08f4407a34c0900 (MD5)Approved for entry into archive by Anderson Silva ([email protected]) on 2015-05-11T12:44:28Z (GMT) No. of bitstreams: 1 Screening for decreased glomerular filtration rate and associated risk factors in a cohort of HIV-infected patients in a middle-income country.pdf: 183300 bytes, checksum: c4e1fabfd912ba83a08f4407a34c0900 (MD5)Made available in DSpace on 2015-05-11T18:07:25Z (GMT). No. of bitstreams: 1 Screening for decreased glomerular filtration rate and associated risk factors in a cohort of HIV-infected patients in a middle-income country.pdf: 183300 bytes, checksum: c4e1fabfd912ba83a08f4407a34c0900 (MD5) Previous issue date: 2014Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil / Universidade do Estado do Rio de Janeiro. Faculdade de Ciências Médicas. Hospital Universitário Pedro Ernesto. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil.Universidade do Estado do Rio de Janeiro. Faculdade de Ciências Médicas. Departamento de Patologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, BrasiFundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST e AIDS. Rio de Janeiro, RJ, Brasil.Universidade do Estado do Rio de Janeiro. Faculdade de Ciências Médicas. Hospital Universitário Pedro Ernesto. Rio de Janeiro, RJ, Brasil.With the introduction of combined active antiretroviral therapy and the improved survival of HIV-infected patients, degenerative diseases and drug toxicity have emerged as long-term concerns. We studied the prevalence of decreased glomerular filtration rate (GFR) and associated risk factors in a cohort of HIV-infected patients from a middle-income country. Our cross-sectional study included all adult patients who attended an urban outpatient clinic in 2008. GFR was estimated using the CKD-EPI equation. The prevalence ratio (PR) of decreased GFR (defined as ,60 mL/min/1.73 m2) was estimated using generalizing linear models assuming a Poisson distribution. We analyzed data from 1,970 patients, of which 82.9% had been exposed to ART. A total of 249 patients (12.6%) had a GFR between 60 and 89 mL/min/1.73 m2, 3.1% had a GFR between 30 and 59, 0.3% had a GFR between 15 and 29, and 0.4% had a GFR ,15. Decreased GFR was found in only 74 patients (3.8%). In the multivariate regression model, the factors that were independently associated with a GFR below 60 mL/min/1.73 m2 were as follows: age $50 years (PR = 3.4; 95% CI: 1.7–6.8), diabetes (PR = 2.0; 95% CI: 1.2–3.4), hypertension (PR = 2.0; 95% CI: 1.3–3.2), current CD4+ cell count ,350 cells/mm3 (PR = 2.1; 95% CI: 1.3–3.3), past exposure to tenofovir (PR = 4.7; 95% CI: 2.3–9.4) and past exposure to indinavir (PR = 1.7; 95% CI: 1.0–2.8). As in high-income countries, CKD was the predominant form of kidney involvement among HIV-infected individuals in our setting. The risk factors associated with decreased glomerular filtration were broad and included virus-related factors as well as degenerative and nephrotoxic factors. Despite the potential for nephrotoxicity associated with some antiretroviral drugs, in the short-term, advanced chronic renal disease remains very rare

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

Evolution over Time of Ventilatory Management and Outcome of Patients with Neurologic Disease∗

OBJECTIVES: To describe the changes in ventilator management over time in patients with neurologic disease at ICU admission and to estimate factors associated with 28-day hospital mortality. DESIGN: Secondary analysis of three prospective, observational, multicenter studies. SETTING: Cohort studies conducted in 2004, 2010, and 2016. PATIENTS: Adult patients who received mechanical ventilation for more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 20,929 patients enrolled, we included 4,152 (20%) mechanically ventilated patients due to different neurologic diseases. Hemorrhagic stroke and brain trauma were the most common pathologies associated with the need for mechanical ventilation. Although volume-cycled ventilation remained the preferred ventilation mode, there was a significant (p < 0.001) increment in the use of pressure support ventilation. The proportion of patients receiving a protective lung ventilation strategy was increased over time: 47% in 2004, 63% in 2010, and 65% in 2016 (p < 0.001), as well as the duration of protective ventilation strategies: 406 days per 1,000 mechanical ventilation days in 2004, 523 days per 1,000 mechanical ventilation days in 2010, and 585 days per 1,000 mechanical ventilation days in 2016 (p < 0.001). There were no differences in the length of stay in the ICU, mortality in the ICU, and mortality in hospital from 2004 to 2016. Independent risk factors for 28-day mortality were age greater than 75 years, Simplified Acute Physiology Score II greater than 50, the occurrence of organ dysfunction within first 48 hours after brain injury, and specific neurologic diseases such as hemorrhagic stroke, ischemic stroke, and brain trauma. CONCLUSIONS: More lung-protective ventilatory strategies have been implemented over years in neurologic patients with no effect on pulmonary complications or on survival. We found several prognostic factors on mortality such as advanced age, the severity of the disease, organ dysfunctions, and the etiology of neurologic disease

Cardiac myosin activation with omecamtiv mecarbil in systolic heart failure

BACKGROUND The selective cardiac myosin activator omecamtiv mecarbil has been shown to improve cardiac function in patients with heart failure with a reduced ejection fraction. Its effect on cardiovascular outcomes is unknown. METHODS We randomly assigned 8256 patients (inpatients and outpatients) with symptomatic chronic heart failure and an ejection fraction of 35% or less to receive omecamtiv mecarbil (using pharmacokinetic-guided doses of 25 mg, 37.5 mg, or 50 mg twice daily) or placebo, in addition to standard heart-failure therapy. The primary outcome was a composite of a first heart-failure event (hospitalization or urgent visit for heart failure) or death from cardiovascular causes. RESULTS During a median of 21.8 months, a primary-outcome event occurred in 1523 of 4120 patients (37.0%) in the omecamtiv mecarbil group and in 1607 of 4112 patients (39.1%) in the placebo group (hazard ratio, 0.92; 95% confidence interval [CI], 0.86 to 0.99; P = 0.03). A total of 808 patients (19.6%) and 798 patients (19.4%), respectively, died from cardiovascular causes (hazard ratio, 1.01; 95% CI, 0.92 to 1.11). There was no significant difference between groups in the change from baseline on the Kansas City Cardiomyopathy Questionnaire total symptom score. At week 24, the change from baseline for the median N-terminal pro-B-type natriuretic peptide level was 10% lower in the omecamtiv mecarbil group than in the placebo group; the median cardiac troponin I level was 4 ng per liter higher. The frequency of cardiac ischemic and ventricular arrhythmia events was similar in the two groups. CONCLUSIONS Among patients with heart failure and a reduced ejection, those who received omecamtiv mecarbil had a lower incidence of a composite of a heart-failure event or death from cardiovascular causes than those who received placebo. (Funded by Amgen and others; GALACTIC-HF ClinicalTrials.gov number, NCT02929329; EudraCT number, 2016 -002299-28.)