Duplex Stainless Steels (DSSs) are biphasic austenite-ferrite stainless steels, with higher mechanical properties and corrosion resistance than the other stainless steels grades. Impact toughness is ...a very important mechanical property and even though DSSs have a lower impact toughness as compared to the austenitic grades, the transition to ductile to brittle behavior is more gradual and it occurs at lower temperature than ferritic grades. On the other hand, DSSs suffer from embrittlement due to secondary phase precipitation, which affects all mechanical and corrosion properties, in particular impact toughness, even in low amount.
In this research paper, the influence of a small amount (< 2%) and different morphologies of secondary phases (coarse and finely dispersed) on the ductile to brittle transition of standard Duplex Stainless Steel UNS S32205 was studied. Two isothermal heat treatments were conducted on the solubilized DSS in order to precipitate the same amount but different morphologies of secondary phases. Charpy tests were conducted on a temperature range between 20 °C and − 196 °C.
The wrought material retained a very good impact toughness even at − 90 °C (100 J), but a small volume fraction of secondary phases affected the impact toughness even at room temperature. Coarser secondary phases affect the impact toughness largely as compared to small and finely dispersed particles.
The Nuss procedure for pectus excavatum requires that the sternal elevation be maintained by indwelling metal bars that are traditionally removed approximately 3 y after the repair.
A retrospective ...cohort study was conducted of all patients who underwent primary Nuss repair from 2007 to 2018 in two institutions and had a follow-up of at least 24 mo. Pectus bars had been left in place beyond 3 y in patients concerned over possible recurrence after bar removal. Structured interviews were held to assess pain, chest tightness, or other discomfort, and any adverse events related to pectus bars. Results were compared between patients in whom pectus bars were removed after 3 y (standard group) and those in whom bars were left in place longer (extended bar duration group).
Two hundred and thirty-one patients (91% males, mean age 23.9 ± 8.3, mean Haller index 4.9 ± 2.3) were included. Bar duration was 30.6 ± 6.6 mo in the standard group (51 patients) versus 69.1 ± 26.3 mo in the extended group (180 patients). Some discomfort was reported by 81.6% in the standard group versus 62.9% in the extended group (P = 0.033), and discomfort occurring at least monthly or more often was only reported by 30% in the standard versus 30.3% in the extended group (P = 1.000). Quality of life improved in 92.6% of the standard group versus 94.7% of the extended group (P = 1.000). No significant adverse events were reported in either group.
Our data suggest that an extended bar duration after the Nuss repair may not cause any adverse event nor negatively affect quality of life.
Duplex Stainless steels (DSS) are biphasic austeno-ferritic steels in which the best combination of mechanical and corrosion resistance properties is achieved for almost equal volume fraction of the ...phases. These steels are classified according to their pitting corrosion resistance, assessed by the PREN index (Pitting Resistance Equivalent Number) which, although qualitatively, is widely employed as comparison. The present work is aimed to study the pitting resistance of four DSS grades (SAF 2101, 2304, 2205 and 2507) in the as-received condition and after isothermal aging in the critical range 750°C-900°C, to highlight the effect of secondary phases precipitation on the corrosion behavior. The materials were potentiodynamically tested in artificial seawater (pH7) at room temperature and the corresponding Critical Pitting Temperatures (CPT) were determined according to ASTM G150. Secondary phase precipitation mainly affected the lean duplex grades whereas the high-alloyed DSS were more stable even if large precipitation occurred.
A 71-day study was conducted to explore the effect of increasing dietary levels (0, 250, 500, 1000 mg kg feed
; D0, D250, D500 and D1000, respectively) of a blend of microencapsulated organic acids ...(OA, specifically citric and sorbic acid) and nature identical compounds (NIC, specifically thymol and vanillin), on growth, intestinal immune parameters and gut microbiota (GM) of European sea bass juveniles reared under normal and subsequently suboptimal environmental conditions (high temperature, 30.0 ± 0.4 °C and low oxygen, 4.6 ± 0.6 mg L
). OA and NIC did not promote growth, feed utilisation and feed intake at the inclusion tested but induced a significantly upregulation of IL-8, IL-10 and TGFβ. GM analyzed by next-generation sequencing showed that OA and NIC were able to exert prebiotic properties stimulating the development of beneficial bacteria taxa such as Lactobacillus, Leuconostoc, and Bacillus sp. Picrust analyses displayed a significant potential functional reconfiguration of GM promoting a decrease in inflammation-promoting and homeostatic functions at increasing OA and NIC administration. For the first time on this species the exposure to suboptimal rearing conditions was able to modify GM structure reducing LAB and increasing Proteobacteria, findings which were consistent with the inflammatory process observed at mRNA level.
A systematic characterization of the genetic alterations driving ALCLs has not been performed. By integrating massive sequencing strategies, we provide a comprehensive characterization of driver ...genetic alterations (somatic point mutations, copy number alterations, and gene fusions) in ALK− ALCLs. We identified activating mutations of JAK1 and/or STAT3 genes in ∼20% of 88 ALK− ALCLs and demonstrated that 38% of systemic ALK− ALCLs displayed double lesions. Recurrent chimeras combining a transcription factor (NFkB2 or NCOR2) with a tyrosine kinase (ROS1 or TYK2) were also discovered in WT JAK1/STAT3 ALK− ALCL. All these aberrations lead to the constitutive activation of the JAK/STAT3 pathway, which was proved oncogenic. Consistently, JAK/STAT3 pathway inhibition impaired cell growth in vitro and in vivo.
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•Co-occurring somatic mutations of JAK1 and STAT3 promote oncogenesis•Novel chimera fuse transcription/repressor domains to tyrosine kinases (TKs)•Dual functional TK fusions are oncogenic and mediate STAT3 transformation•JAK/STAT3 inhibitors have therapeutic efficacy in pre-clinical ALCL models
Crescenzo et al. provide a comprehensive characterization of driver genetic alterations in ALK− anaplastic large cell lymphomas (ALCLs) and uncover mechanisms leading to the constitutive activation of STAT3 in ALK− ALCL. JAK/STAT3 inhibitors have therapeutic efficacy in pre-clinical ALCL models.
IMPORTANCE: Many patients with coronavirus disease 2019 (COVID-19) are critically ill and require care in the intensive care unit (ICU). OBJECTIVE: To evaluate the independent risk factors associated ...with mortality of patients with COVID-19 requiring treatment in ICUs in the Lombardy region of Italy. DESIGN, SETTING, AND PARTICIPANTS: This retrospective, observational cohort study included 3988 consecutive critically ill patients with laboratory-confirmed COVID-19 referred for ICU admission to the coordinating center (Fondazione IRCCS Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy) of the COVID-19 Lombardy ICU Network from February 20 to April 22, 2020. Infection with severe acute respiratory syndrome coronavirus 2 was confirmed by real-time reverse transcriptase–polymerase chain reaction assay of nasopharyngeal swabs. Follow-up was completed on May 30, 2020. EXPOSURES: Baseline characteristics, comorbidities, long-term medications, and ventilatory support at ICU admission. MAIN OUTCOMES AND MEASURES: Time to death in days from ICU admission to hospital discharge. The independent risk factors associated with mortality were evaluated with a multivariable Cox proportional hazards regression. RESULTS: Of the 3988 patients included in this cohort study, the median age was 63 (interquartile range IQR 56-69) years; 3188 (79.9%; 95% CI, 78.7%-81.1%) were men, and 1998 of 3300 (60.5%; 95% CI, 58.9%-62.2%) had at least 1 comorbidity. At ICU admission, 2929 patients (87.3%; 95% CI, 86.1%-88.4%) required invasive mechanical ventilation (IMV). The median follow-up was 44 (95% CI, 40-47; IQR, 11-69; range, 0-100) days; median time from symptoms onset to ICU admission was 10 (95% CI, 9-10; IQR, 6-14) days; median length of ICU stay was 12 (95% CI, 12-13; IQR, 6-21) days; and median length of IMV was 10 (95% CI, 10-11; IQR, 6-17) days. Cumulative observation time was 164 305 patient-days. Hospital and ICU mortality rates were 12 (95% CI, 11-12) and 27 (95% CI, 26-29) per 1000 patients-days, respectively. In the subgroup of the first 1715 patients, as of May 30, 2020, 865 (50.4%) had been discharged from the ICU, 836 (48.7%) had died in the ICU, and 14 (0.8%) were still in the ICU; overall, 915 patients (53.4%) died in the hospital. Independent risk factors associated with mortality included older age (hazard ratio HR, 1.75; 95% CI, 1.60-1.92), male sex (HR, 1.57; 95% CI, 1.31-1.88), high fraction of inspired oxygen (Fio2) (HR, 1.14; 95% CI, 1.10-1.19), high positive end-expiratory pressure (HR, 1.04; 95% CI, 1.01-1.06) or low Pao2:Fio2 ratio (HR, 0.80; 95% CI, 0.74-0.87) on ICU admission, and history of chronic obstructive pulmonary disease (HR, 1.68; 95% CI, 1.28-2.19), hypercholesterolemia (HR, 1.25; 95% CI, 1.02-1.52), and type 2 diabetes (HR, 1.18; 95% CI, 1.01-1.39). No medication was independently associated with mortality (angiotensin-converting enzyme inhibitors HR, 1.17; 95% CI, 0.97-1.42; angiotensin receptor blockers HR, 1.05; 95% CI, 0.85-1.29). CONCLUSIONS AND RELEVANCE: In this retrospective cohort study of critically ill patients admitted to ICUs in Lombardy, Italy, with laboratory-confirmed COVID-19, most patients required IMV. The mortality rate and absolute mortality were high.
In the last years, the research on ultraviolet-C (UV-C) light emitting diodes (LEDs) focused its efforts on the solution of major problems that limited the emitted optical power (OP) and that caused ...the sudden failure of the devices. This led to the availability in the market of some devices with interesting electro-optical characteristics and promising lifetimes. In this article, we decided to study the reliability of four commercial UV-C LEDs with a nominal wavelength of 265 nm, in order to study their lifetime and their possible implementation in disinfection systems. We submitted the devices to an accelerated lifetime test of 20000 min, at the absolute maximum current indicated in their respective datasheets. During the tests, we carried out electrical and optical measurements, and we evaluated their spectral characteristics before and after aging. Once identified the best sample, we compared it with the best sample at 275 nm studied in our previous work, in order to show all the problems to consider if these LEDs have to be used in machinery that will be placed on the market.
The aim of this paper is to investigate the degradation mechanisms of UV-B AlGaN-based light-emitting diodes (LEDs) submitted to constant current stress beyond the typical application conditions. We ...demonstrate the existence of two main degradation mechanisms that significantly impact the relative amplitude of the main quantum well (QW) peak at 310 nm and of a parasitic peak at ~340 nm related to the electron overflow toward the last quantum barrier before the p-side. These mechanisms are thoroughly investigated by means of electrical and optical measurements, and by photocurrent (PC) spectroscopy. We demonstrate that in the first 50 h of stress, degradation is caused by an increased defect density in the last quantum barrier and/or carrier escape from the QWs, which results in a decrease in the QW emission and in an increase in the parasitic peak at 340 nm. For longer stress times, degradation is dominated by a diffusion process, causing an increase in defect density and nonradiative recombination in the LED. This has a direct impact on both the QW peak and the parasitic peak, which show a significant decrease for long stress times. PC spectroscopy demonstrates that the defects responsible for degradation are most likely located next to mid-gap, thus acting as efficient nonradiative recombination centers.
Herein, the main factors and mechanisms that limit the reliability of gallium nitride (GaN)‐based light‐emitting diodes (LEDs) are reviewed. An overview of the defects characterization techniques ...most relevant for wide‐bandgap diodes is provided first. Then, by introducing a catalogue of traps and deep levels in GaN and computer‐aided simulations, it is shown which types of defects are more detrimental for the radiative efficiency of the devices. Gradual degradation mechanisms are analyzed in terms of their specific driving force: a separate analysis of recombination‐enhanced processes, driven by nonradiative recombination and/or temperature‐assisted processes, such as defects or impurity diffusion, is presented. The most common lifetime estimation methods and standards adopted for solid‐state luminaires are also reported on. Finally, the paper concludes by examining which are the typical degradation and failure mechanisms exhibited by LEDs submitted to electrical overstress.
This article provides an overview of the main factors and mechanisms that limit the short‐ and long‐term reliability of modern GaN‐based light‐emitting diodes. Relevant defects, and related characterization techniques, for III‐N materials are analyzed, and their impact on device performance is evaluated.
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