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Selective laser melting (SLM) is one of the most widely used additive manufacturing technologies. Fabricating nickel-based superalloys with SLM has garnered significant interest from the industry and the research community alike due to the excellent high temperature properties and thermal stability exhibited by the alloys. Haynes-282 alloy, a γ′-phase strengthened Ni-based superalloy, has shown good high temperature mechanical properties comparable to alloys like R-41, Waspaloy, and 263 alloy but with better fabricability. A study and comparison of the effect of different heat-treatment routes on microstructure and mechanical property evolution of Haynes-282 fabricated with SLM is lacking in the literature. Hence, in this manuscript, a thorough investigation of microstructure and mechanical properties after a three-step heat treatment and hot isostatic pressing (HIP) has been conducted. In-situ heat-treatment experiments were conducted in a transmission electron microscopy (TEM) to study γ′ precipitate evolution. γ′ precipitation was found to start at 950 °C during in-situ heat-treatment. Insights from the in-situ heat-treatment were used to decide the aging heat-treatment for the alloy. The three-step heat-treatment was found to increase yield strength (YS) and ultimate tensile strength (UTS). HIP process enabled γ′ precipitation and recrystallization of grains of the as-printed samples in one single step.

Background: Irritable bowel syndrome (IBS) was found in 11% of the general population worldwide. The current pharmacologic management of IBS was unsatisfactory, and it was accompanied by a number of adverse events. Melatonin was found to play an important role in gastrointestinal smooth muscle motility. Dysregulation of endogenous melatonin secretion has been found in IBS patients. Exogenous melatonin supplement has become one alternative treatment for IBS, but the evidence is inconclusive. The current meta-analysis sought to determine the efficacy of exogenous melatonin supplement in improving IBS severity in IBS patients. Methods: We included randomized controlled trials (RCTs) that investigated the efficacy of exogenous melatonin supplement in ameliorating IBS severity in IBS patients. This meta-analysis was conducted using a random effects model. The primary target outcomes were changes in IBS severity associated with melatonin or placebo. Results: This meta-analysis of 4 RCTs and 115 participants revealed that exogenous melatonin supplement was associated with significantly better improvement in overall IBS severity than placebo (k = 4, Hedges’ g = 0.746, 95% confidence intervals = 0.401–1.091, p

Irritable bowel syndrome (IBS) was found in 11% of the general population worldwide. The current pharmacologic management of IBS was unsatisfactory, and it was accompanied by a number of adverse events. Melatonin was found to play an important role in gastrointestinal smooth muscle motility. Dysregulation of endogenous melatonin secretion has been found in IBS patients. Exogenous melatonin supplement has become one alternative treatment for IBS, but the evidence is inconclusive. The current meta-analysis sought to determine the efficacy of exogenous melatonin supplement in improving IBS severity in IBS patients. We included randomized controlled trials (RCTs) that investigated the efficacy of exogenous melatonin supplement in ameliorating IBS severity in IBS patients. This meta-analysis was conducted using a random effects model. The primary target outcomes were changes in IBS severity associated with melatonin or placebo. This meta-analysis of 4 RCTs and 115 participants revealed that exogenous melatonin supplement was associated with significantly better improvement in overall IBS severity than placebo (k = 4, Hedges' g = 0.746, 95% confidence intervals = 0.401–1.091, p < 0.001). The subgroup without concurrent medication had the same result (p < 0.001). In addition, exogenous melatonin supplement was also associated with significantly better improvement in IBS pain severity (p < 0.001) and quality of life (p = 0.007) than placebo, but not in abdominal distension (p = 0.111) or sleep quality (p = 0.142). Finally, melatonin was associated with similar safety profiles with placebo. This meta-analysis provides evidence for the use of exogenous melatonin in IBS patients to ameliorate overall IBS severity, IBS pain severity, and quality of life. PROSPERO CRD42021269451. [ABSTRACT FROM AUTHOR]

A silver microwire was formed on a silver sulfide surface in a directional and reversible manner. This wire formed upon applying an electric field between a tip-less atomic force microscopy probe placed on the Ag2S surface and a grounded silver electrode embedded in the surface. The process was studied in real-time with optical microscope and a discussion was provided on how the morphological instability was violated. A numerical model based on the mixed ionic-electronic transport was developed to study the observation and a good match of growth rates was found. The fast metal wire growth phenomenon observed here has potential in applications for electronics as well as plasmonic sensors and waveguides [ABSTRACT FROM AUTHOR]