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A high-strength low-alloy (HSLA) steel plate of 10 mm thickness underwent submerged arc welding with enhanced fluxes containing additional titanium oxide (TiO2) or vanadium oxide (V2O5). The addition of TiO2 led to the development of a finer acicular ferrite structure but coarsening the carbide and martensite/austenite (M/A) constituents, which marginally improved the hardness, tensile strength, and ductility of weld metal. Conversely, incorporating V2O5 facilitated a substantial vanadium absorption (0.7 wt. %) in the weld metal, giving rise to a distinctive acicular microstructure less reliant on ferrite nucleation at non-metallic inclusions than conventional acicular ferrite. The distinctive microstructure, unique to vanadium steels, combined lath bainite with irregularly shaped granular bainite. The resultant dual-mode bainitic structure, coupled with a more uniform distribution of refined microphase constituents, outperformed the conventional acicular ferrite, delivering more than 20% and 13% improvements in yield and tensile strengths respectively, as evidenced by transverse tensile tests on the weld metals.

This study presents processing and properties of dual-phase (DP) steels, which contain islands of martensite among ferrite grains effectively reinforced by abundant carbide particles. To this end, a medium-carbon, low-alloyed steel plate with an initial ferrite-pearlite microstructure underwent cold rolling for 80% thickness reduction. Specimens obtained from the cold rolled strip were then heated in a neutralized salt bath at various temperatures ranging from 600 to 730 °C for 10 ks, followed by water quenching. The resulting microstructures and mechanical properties were analyzed. Preceding the formation of austenite during intercritical annealing, recrystallization led to the formation of a spheroidized ferrite microstructure with a high number of carbide particles dispersed mainly within the recrystallized ferrite grains. Initially, austenite grains formed on the carbides located at the boundaries between ferrite grains, followed by the formation of austenite on the carbides still present within the ferrite grains. Quenching from 715 °C resulted in a DP microstructure with intergranular martensite while increasing the annealing temperature to 725 °C led to the creation of intragranular martensite additionally. The study also focused on the distribution of alloying elements in the DP microstructure, revealing an enrichment of carbides with Mn, Cr, and Mo. Furthermore, an enrichment of martensite islands with manganese atoms was identified, but no comparable enrichment with carbon atoms was observed. The specimens annealed at 715–725 °C, which consisted of a martensite volume fraction ranging from 0.15 to 0.45, exhibited a superior balance of strength and ductility, as well as an outstanding work hardening exponent.

Friction stir processing (FSP) effectively improves the fatigue strength of arc-welded joints; however, wear of tools is inevitable in case of high-strength materials. Notably, a new benefit has been discovered: compressive residual stress is applied on the FSPed steel surface, alloyed with the WC tool constituent elements, contrasting with the tensile residual stress typically applied via conventional FSP. To elucidate the mechanism of compressive residual stress application, FSP was performed on a low-carbon steel plate at various rotational speeds. The alloyed topmost layers in the stir zone comprised martensite structures with a small amount of retained austenite grains, resulting in a hardness increase owing to the tool constituent elements. The residual stresses on the stir zone surface were influenced by the alloying contents and the corresponding martensite start temperature (Ms). Compressive residual stresses were maximized at an Ms of approximately 150 °C owing to martensitic transformation expansion near room temperature. Lowering the Ms below approximately 150 °C led to tensile residual stresses and an increased volume fraction of the retained austenite, suggesting that martensitic transformation expansion is insufficient to apply compressive residual stress. Conversely, the retained austenite can resist plastic deformation and crack propagation through deformation-induced martensitic transformation, thereby enhancing fatigue properties.

Asthma exacerbation is a significant clinical problem that causes resistance to corticosteroid therapy and elevated hospitalization risk. Src family kinases (SFKs) contribute to various steps of the immune response, such as airway inflammation in viral or bacterial infections and allergic asthma. Therefore, we determined the effects of dasatinib (DAS), a typical Src inhibitor, on a murine asthma exacerbation model induced by house dust mites (HDM) and synthetic analog of double-stranded RNA, poly(I:C). A/J mice were sensitized to intrapreneurial HDM twice every seven days and challenged with intranasal HDM once every second day for a total of six exposures, and/or exposed to poly(I:C) twice daily for three consecutive days. Drug treatments were performed twice daily for three days, starting one day after the last HDM challenge or 2 h before each poly(I:C) exposure. DAS improved poly(I:C)-induced acute inflammation dose-dependently. Both DAS and fluticasone propionate (FP) attenuated HDM-induced allergic airway inflammation. However, in HDM and poly(I:C) induced-asthma exacerbated mice, DAS significantly improved inflammatory cells in bronchoalveolar lavage fluid and histological changes in the lungs, whereas FP did not. Therefore, SFKs are important targets for controlling severe asthma refractory to conventional therapies.

Fatigue strength of fusion-welded joints is lower than that of the base metal due to stress concentration, tensile residual stress, and microstructural degradation at the weld toe. To improve these issues, friction stir processing (FSP) using a spherical tip tool was directly applied to the weld toe of high-strength low-alloy steel joints. The toe geometry was successfully modified without defect formation, resulting in 25% reduction in fatigue notch factor in comparison to the as-welded joints. Significant grain refinement due to FSP increased hardness beneath the toe surface. In addition, compressive residual stress related to tool wear was produced on the FSP surface. Bending fatigue strength was improved by these benefits, with dependence on the tool travel speed. Fatigue crack initiation occurred at the toe surface for all the joints. Although high travel speed FSP produced serrated surface resulting in degradation of FSP improvement in fatigue strength, low travel speed FSP contributed to reduction of surface roughness leading to maximum FSP improvement of 50% in fatigue strength. The results obtained in this study suggest the encouraging prospect of direct application of FSP to weld toes as new post-weld treatment for steel joints. Keywords: Friction stir processing, Post-weld treatment, High-strength low-alloy steel, Fatigue strength, Weld geometry, Residual stress

This study aimed to obtain a W/Cu clad with high bending strength using explosive welding (EW), since its thermo-physical property combination is attractive for industrial applications. Cladding both metal plates using EW results cracks in W plates from the surface toward interface. Eliminating the cracks in W plate of clads was a major challenge in this study. The formation of cracks is fundamentally due to generation of high-intensity reflected tensile waves as a consequence of the undissipated imparted kinetic energy (KE) at the collision interface. A crack-free W plate as well as higher bending strength have been obtained in the W/Cu clads produced at the highest collision velocity with lower collision angles among three samples produced at different horizontal collision velocities. The EW clad interface exhibited an intermediate layer (IL), which was associated with higher consumption of KE at the interface, leading to reduction of the intensity of reflected tensile waves. The IL consisted of nanometer- and submicrometer-sized W fragments distributed in a Cu matrix, leading to higher hardness than a Cu plate. This could have contributed to the increase in the bending strength of the clads. (187 words).

A systematic, comparative study was carried out to quantitatively characterize the bending strength of wavy interfaces with and without an intermediate layer (IL) in Nb/Cu and Ta/Cu explosive clads. The clads having wavy interfaces with and without an IL were obtained at horizontal high and low collision velocities (HCV and LCV) in the explosive welding, respectively. The stress-strain curves of all the clads were similar in three-point bending tests, but the clads with an IL exhibited higher bending stress than those without an IL. Moreover, cracks were observed in the Nb plate of Nb/Cu clads without an IL, but no cracks in that with an IL. TEM observation confirmed coexistence of ultrafine refractory metal and Cu phases in the ILs. In addition, the Ta-Cu-based intermetallic compound or dodecagonal quasicrystal, which is a non-equilibrium phase, were also observed along with coexistence of Ta and Cu phases in the ILs of Ta/Cu interface. Cladding at HCV and a lower collision angle assisted in resultant less strain in refractory metal plates near the joint interfaces than those at LCV, due to IL formation. The ILs assisted in obtainment of interfaces of higher hardness, leading to higher bending-stress clads without losing large elongation. Keywords: Explosive welding, Wavy interface, Intermediate layer, Ultra-fine scale coexistence, Non-equilibrium intermetallic compound, Quasicrystal

Resumo: A DPOC constitui um problema de saúde global de importância crescente, com enorme impacto nos custos directos e indirectos em recursos de saúde. Apesar do seu impacto, pouco se sabe ainda sobre os mecanismos celulares, moleculares e genéticos desta doença, e as te-rapêuticas farmacológicas actualmente disponíveis não influenciam a progressão da doença ou a mortalidade. A limitação do débito aéreo avaliada pela redução do volume expiratório máximo no 1.º segundo (FEV1) progride muito lentamente ao longo de várias décadas, condicionando o aparecimento de sintomas em adultos acima dos 40 anos ou já na terceira idade. Desta forma, a prevalência da DPOC é dependente da idade, sugerindo uma relação íntima entre a pato-génese da DPOC e a do envelhecimento.A senescência ou processo de envelhecimento definese como o declínio progressivo da homeostasia que ocorre após estar completa a fase reprodutiva da vida e conduz a um risco aumentado de doença e de morte. Segundo Kirkwood1, o envelhecimento resulta da interacção entre a lesão e a reparação, como resultado da energia produzida pelo indivíduo para manter a integridade orgânica e proteger o ADN da agressão oxidativa. A falência orgânica ou celular na manutenção ou reparação resulta de uma acção integrada entre genes, ambiente e defeitos intrínsecos do organismo. Subjacente ao processo de envelhecimento, existe uma acumulação progressiva de danos a nível molecular.As alterações a nível celular causam reacções inflamatórias, e estas, por sua vez, exacerbam as lesões celulares existentes. Desta forma, os factores inflamatórios e anti-inflamatórios modulam a evolução do envelhe-cimento. As alterações inflamatórias e estruturais associadas ao envelhecimento resultam da falência em eliminar os radicais de oxigénio (ROS), da falência em reparar o ADN lesado e do encurtamento do teló-mero. Os telómeros protegem as extremidades dos cromossomas, mas, quando se encontram expostos a elevados níveis de stress oxidativo, vão-se encurtando progressivamente à medida que as células se dividem. Com o envelhecimento, a perda e encurtamento dos telómeros condicionam o declínio da capacidade para as células se dividirem â senescência replicativa.O stress oxidativo causa lesão do ADN, o que acelera o processo de envelhecimento e aumenta o risco de cancro (exemplo, a senescência da glândula mamária e o risco elevado de cancro da mama).Os gases ambientais, como o fumo do cigarro ou outros poluentes, podem acelerar o envelhecimento do pulmão ou agravar os eventos relacionados com o en-velhecimento pulmonar através de uma resolução defeituosa da inflamação. A redução das moléculas anti-envelhecimento como as histona desacetilases e as sirtuínas, pode igualmente induzir a progressão acelerada para a DPOC.Ainda não é claro como é que o processo de envelhe-cimento está envolvido no declínio da função pulmonar e na inflamação da DPOC. Contudo, o pulmão do idoso e o pulmão do doente com DPOC apresen-tam muitas semelhanças. A lesão provocada pelo fumo do cigarro e outros pneumopoluentes conduz a um declínio mais acelerado da função pulmonar, com falência dos mecanismos de reparação e de manuten-ção. A presença de inflamação nos dois processos (en-velhecimento e DPOC) traduz-se em acumulação de neutrófilos, na activação da NF-kB e na elevação dos níveis plasmáticos de interleucinas IL-6, IL-8 e TNF-α. Também os telómeros das células alveolares tipo II, das células endoteliais e das células mononu-cleares em doentes com enfisema são significativamente mais curtos do que em indivíduos não fumadores da mesma idade.Neste artigo, os autores descrevem ainda estudos recentes sobre os mecanismos de transdução de sinal, como as vias da acetilação das proteínas envolvidas no processo de envelhecimento, identificando assim novas moléculas anti-envelhecimento que poderão constituir abordagens inovadoras na terapêutica da DPOC. Os antioxidantes actualmente disponíveis, como a N-acetilcisteína, não são suficientemente potentes para reduzir o stress oxidativo nos pulmões. Existem vários fármacos em desenvolvimento, como os novos análogos da glutationa e da superoxido dismutase (exemplo, o sulforafano) e novas moléculas antienvelhecimento com maior controlo sobre a resis-tência ao stress oxidativo, a reparação do ADN e a inflamação, como os activadores das sirtuínas (exem-plo, o resveratrol, o activador específico da SIRT1 ou o activador da SIRT6).

Oligella urethralis and Trueperella bernardiae are rare causes of bacteremia. A 96-year-old female nursing home resident with diabetes presented with polymicrobial bloodstream infection comprising these organisms and obstructive urinary tract infection. O. urethralis identified from blood cultures was resistant to fluoroquinolones and non-fourth-generation cephalosporins. Cases must be accumulated to define the clinical features of these organisms for infection control.