The application of press hardening steels is spreading from automobiles, where crashworthiness demands are critical, to other segments, such as the agricultural and road transport industries. ...However, the operational conditions to which such equipment is exposed requires the application of heavier sheet gages and adapted joining processes. In this context, fatigue is recognized as the critical failure mode. The present article describes the procedures and results of fatigue testing performed on GMAW-CSC and PAW butt-welded specimens of 1500 MPa press hardening steel. Both methods are suitable alternatives to laser welding when joining relatively heavy-gaged components. The obtained fatigue results are also related to heat-affected zone characteristics and weld bead surfaces. Additionally, some ground-flush GMAW-CSC specimens were tested. The test results indicate that both welding procedures provide suitable fatigue performance. As-welded GMAW-CSC joints on this ultra-high strength steel accomplished a fatigue performance similar to welds of conventional steel. However, a remarkable performance increase was observed after flush grinding the weld beads. The plasma welding process presented less good results due to the more extensive manufacturing and geometric variability. The results indicate that adopting a suitable arc welding process, in association with post-weld geometry improvement, provides a fatigue performance that is competitive with laser-welded press hardening steels.
The classificatory method is considered a straightforward and robust procedure for the assessment of welded joints in metallic structures. The methodology adopts a set of S–N diagrams with a ...conservative survival rate, which expresses the fatigue performance of the most employed joint configurations. In the design phase, the adoption of a structural detail correlated with a higher curve in the set conducts to high structural integrity. Nevertheless, fatigue phenomenon is essentially multifactorial and, consequently, several optimizing alternatives may be applied for life increasing. Studies focused on continuous (weldless) parts correlate fatigue performance with the material ultimate strength. Transferring this approach to welded parts, adoption of a high-strength filler metal, or any procedure intended to mitigate metallurgical inhomogeneity in the weld-affected region may propitiate fatigue life improvement. In other sense, issues related to bead geometry, notably the notch effect associated with weld toe, are also reported to have an essential influence on fatigue life of structural details. This work aims to counterbalance material and bead geometry aspects related to fatigue performance of butt joints subjected to repeated transverse loading. Two welding processes, FCAW and GMAW, as well as different filler metals and parameters, were adopted for specimens manufacturing. The ASTM-A572-Gr.50 steel was employed as a parent metal. After welding, FCAW joints presented better mechanical and metallurgical characteristics. Additionally, in order to characterize the relevance of the notch effect, half of the specimens had the original bead geometry maintained, while the others underwent a manual removal of the reinforcement. The obtained results indicate that FCAW joints present better fatigue performance in the as-welded state. However, after removing the reinforcements, both welding processes attained similar results, suggesting that the notch effect has more relevance for fatigue life than mechanical and metallurgical characteristics of the joint. Consequently, the superior performance presented by the FCAW joints in the as-welded state is assigned to the final shape of the reinforcements, which is smoother than in the GMAW case. The higher capacity of penetration and better filler metal wettability propitiated by the FCAW process is responsible for the lower notch effect.
Heart failure (HF) is one of the leading causes of hospitalization in adults in Brazil. However, most of the available data is limited to unicenter registries. The BREATHE registry is the first to ...include a large sample of hospitalized patients with decompensated HF from different regions in Brazil.
Describe the clinical characteristics, treatment and prognosis of hospitalized patients admitted with acute HF.
Observational registry study with longitudinal follow-up. The eligibility criteria included patients older than 18 years with a definitive diagnosis of HF, admitted to public or private hospitals. Assessed outcomes included the causes of decompensation, use of medications, care quality indicators, hemodynamic profile and intrahospital events.
A total of 1,263 patients (64±16 years, 60% women) were included from 51 centers from different regions in Brazil. The most common comorbidities were hypertension (70.8%), dyslipidemia (36.7%) and diabetes (34%). Around 40% of the patients had normal left ventricular systolic function and most were admitted with a wet-warm clinical-hemodynamic profile. Vasodilators and intravenous inotropes were used in less than 15% of the studied cohort. Care quality indicators based on hospital discharge recommendations were reached in less than 65% of the patients. Intrahospital mortality affected 12.6% of all patients included.
The BREATHE study demonstrated the high intrahospital mortality of patients admitted with acute HF in Brazil, in addition to the low rate of prescription of drugs based on evidence.
Introdução: A paralisia cerebral é uma desordem crônica de déficit não progressivo do desenvolvimento motor causada por diferentes fatores etiológicos. Objetivo: Analisar o uso de toxina botulínica ...como uma abordagem terapêutica para o tratamento de paralisia cerebral em pacientes pediátricos. Metodologia: Trata-se de um estudo epidemiológico transversal que utilizou dados do SIA-PA do DATASUS, analisando crianças até 14 anos com diagnóstico de paralisia cerebral em 2022. Foram considerados variáveis do estudo o mês, região, faixa etária, raça/cor, sexo e tipo de atendimento. Foi utilizado o Software R para a análise dos dados. Resultados: Ao longo do ano, 12.695 crianças foram atendidas, evidenciando uma prevalência na faixa etária de 5 a 9 anos, de raça/cor branca e do sexo masculino. Análises temporais indicaram variações sazonais nos atendimentos, com maior prevalência entre agosto e setembro para crianças de 0 a 4 anos e, em abril e julho para o grupo de 5 a 9 anos, com maior concentração nas categorias quadriplégica espástica, diplégica espástica e hemiplégica espástica. Quanto ao uso da toxina botulínica, este foi mais proeminente na faixa etária de 5 a 9 anos. Conclusão: Os resultados deste estudo oferecem uma compreensão sobre o perfil de atendimento a pacientes pediátricos com paralisia cerebral no Brasil que fazem uso de toxina botulínica. A análise das unidades de toxina botulínica utilizadas em diferentes subcategorias ressaltou a importância de adaptações personalizadas no tratamento, considerando as necessidades específicas de cada perfil de paciente, especialmente na faixa etária de 5 a 9 anos.
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