Effect of Post-Processing on the Microstructure and Mechanical Properties of Ultra-Low Carbon Steel Fabricated by Selective Laser Melting

In this study, the effects of heat treatments and hot-isotactic pressing (HIP) on the microstructure and mechanical properties of ultra-low carbon steel produced using selective laser melting (SLM) were investigated. Powder and prototypes characterizations including XRD phase analysis, microstructural observations, and hardness were performed. It was found that heat treatments at 1000 ºC and HIP process improved inter-particle bonding very slightly. Significant increases in the grain size were observed for the annealed specimens at 600ºC and above as well as after HIP due to recrystallization and further grain growth, which coincide with the drop in hardness.Mechanical Engineerin

Effect of Scanning Methods in the Selective Laser Melting of 316L/TiC Nanocomposites

Selective laser melting (SLM) is a promising additive manufacturing process that allows for the fabrication of complex functional components by the selective layer-by-layer melting of particles on a powder bed using a high-energy laser beam. In this study, the SLM process was used to fabricate components of TiC/ 316L stainless steel nanocomposite using various laser scanning methods. The results showed that the laser-scanning method used for the SLM process affects the degree of densification, microstructure, and the hardness of the components produced. We believe that the alternative fabrication route presented in this study should significantly increase the use of nanocomposites.Mechanical Engineerin

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Stainless Steel 316L Coatings Produced by Cold Spray for Biomedical Applications

Abstract In this study, the effects of heat treatment on the microstructure and mechanical properties of cold sprayed stainless steel 316L coatings using N2 and He as propellant gases were investigated. Powder and coating characterizations, including coating microhardness, coating porosity, and XRD phase analysis were performed. It was found that heat treatment reduced porosity, improved inter-particle bonding, and increased ductility. XRD results confirmed that no phase transformation occurred during deposition. Significant increase in UTS and ductility was observed for the annealed specimens obtained with nitrogen propellant, whereas little changes were observed for the helium propellant produced specimen

Recurrence of heterotopic ossification after removal in patients with traumatic brain injury: A systematic review

AbstractObjectiveA systematic review of the literature to determine whether in patients with neurological heterotopic ossification (NHO) after traumatic brain injury, the extent of the neurological sequelae, the timing of surgery and the extent of the initial NHO affect the risk of NHO recurrence.Data sourcesWe searched MEDLINE via PubMed and Cochrane library for articles published up to June 2015. Results were compared with epidemiological studies using data from the BANKHO database of 357 patients with central nervous system (CNS) lesions who underwent 539 interventions for troublesome HO.ResultsA large number of studies were published in the 1980s and 1990s, most showing poor quality despite being performed by experienced surgical teams. Accordingly, results were contradictory and practices heterogeneous. Results with the BANKHO data showed troublesome NHO recurrence not associated with aetiology, sex, age at time of CNS lesion, multisite HO, or “early” surgery (before 6months). Equally, recurrence was not associated with neurological sequelae or disease extent around the joint.ConclusionsThe recurrence of NHO is not affected by delayed surgery, neurological sequelae or disease extent around the joint. Surgical excision of NHO should be performed as soon as comorbid factors are under control and the NHO is sufficiently constituted for excision

Development and Validation of a Decision-Making Stratification Algorithm to Optimize the Use of Rapid Diagnostic Testing for Patients with Staphylococcus

Purpose. To evaluate whether introducing rapid diagnostic testing in conjunction with implementing a stratification algorithm for testing eligibility would be an appropriate clinical and cost saving approach. Method. An internal concurrent 4-month observational study was performed. Positive blood cultures continued to be worked up in accordance with standard of care. An additional call to the infectious disease (ID) pharmacy service occurred for all positive blood cultures with Gram-positive cocci in clusters (GPCC). The ID pharmacy service investigated each case using a prespecified stratification algorithm to minimize unnecessary use of rapid identification testing. Results. 43 patients with GPCC were screened. Only nine patients met inclusion criteria for QuickFISH™ testing. The average expected time avoided to optimize antibiotic therapy is 35±16 hours. If the QuickFISH test had been indiscriminately implemented for all cases, the cost for performing this test would have been $5,590. However, using the prespecified algorithm, only 9 patients were tested for a projected cost of$1,170. Conclusion. Introducing rapid diagnostic testing in conjunction with implementing patient stratification algorithm for rapid identification of GPCC from blood cultures in addition to the ID pharmacy intervention will provide a positive impact on the clinical and economic outcomes in our health care setting

Comparing the efficacy and safety of faecal microbiota transplantation with bezlotoxumab in reducing the risk of recurrent Clostridium difficile infections:a systematic review and Bayesian network meta-analysis of randomised controlled trials

The risk of recurrent Clostridium difficile infections (RCDIs) is high when treated with standard antibiotics therapy (SAT) alone. It is suggested that the addition of faecal microbiota transplantation (FMT) or bezlotoxumab after SAT reduces the risk of RCDI. In the absence of head-to-head randomised controlled trials (RCTs), this review attempts to compare the efficacy and safety of bezlotoxumab with FMT in reducing the risk of RCDI in hospitalised patients.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Effects of TiC content on microstructure and mechanical properties of nickel-based hastelloy X nanocomposites manufactured by selective laser melting

The nickel-based Hastelloy X (HX) superalloy is widely applied in the aerospace industry because of its exceptional oxidation resistance and various beneficial properties at high temperatures. HX-based nanocomposites manufactured by additive-manufacturing processes based on powder-bed fusion, such as selective laser melting (SLM), are expected to further enhance the material's mechanical and thermophysical performance. This paper systematically studies the effects of TiC nanoparticle content on the microstructure and tensile performance of SLM-fabricated HX nanocomposites. The results reveal that the microcracking that formed in pure HX was successfully eliminated in the fabricated nanocomposites when 1 wt% and 3 wt% TiC nanoparticles were introduced. The fabricated HX-3 wt.% (HX-3) TiC nanocomposite showed several TiC clusters and a much higher pore-volume percentage (0.15%) compared to the HX-1 wt.% (HX-1) TiC nanocomposite, in which this percentage was determined to be 0.026%. Compared to SLM-fabricated pure HX alloy, the HX-1 nanocomposite exhibited over 19% and 10% improvements in ultimate tensile strength and elongation to failure, respectively. A further increase in TiC content to 3 wt% was not found to further enhance the tensile strength but did result in a 10% loss in elongation to failure in HX-3 nanocomposite. These findings offer a promising pathway to employ SLM to manufacture both high-strength and high-ductility materials through the careful selection of nanoparticle materials and their content

Pharmacy students’ interprofessional experience and performance in advanced pharmacy practice experience rotations amid COVID-19 pandemic

IntroductionInterprofessional education (IPE) is essential in pharmacy training, providing students with vital collaborative skills for real-world healthcare. Advanced Pharmacy Practice Experience (APPE) is integral to IPE, allowing students to apply their knowledge in diverse healthcare settings. The COVID-19 pandemic has disrupted healthcare education and raised concerns about its impact on IPE during APPE rotations. Our study investigates the pandemic’s influence on pharmacy students’ interprofessional interactions and APPE performance.ObjectiveTo assess the interprofessional experiences of fourth-year pharmacy students before and during the COVID-19 pandemic in the context of APPE.MethodsThis retrospective observational study examined the experiences of P4 pharmacy students in the United States during APPEs before and during the pandemic. We employed electronic surveys with 21 questions to gauge interactions and interprofessional team effectiveness, employing Likert scale response options. We compared responses between the 2019–2020 and 2020–2021 APPE rotations using statistical tests.ResultsOur study encompassed 83 and 86 students for the 2019–2020 and 2020–2021 APPE rotations, respectively, achieving a 100% response rate. Amid the pandemic, written communications between pharmacy students and healthcare providers in general medicine rotations increased, while in-person engagement decreased. Pre-COVID, students reported higher colleague referrals and greater interprofessional utilization during ambulatory care rotations.ConclusionCOVID-19 shifted interactions from in-person to written communication between pharmacy students and healthcare providers. Students reported decreased satisfaction with their interprofessional experiences. This research offers insights into the changing landscape of pharmacy education, helping students prepare for evolving challenges in healthcare delivery and education

Investigation on shape deviation of horizontal interior circular channels fabricated by laser powder bed fusion

The fabrication of horizontal interior circular channels poses some unique challenges to the laser powder bed fusion (L-PBF) process. The engineering challenge is to be able to print horizontal interior channels using L-PBF without using support structures, while the scientific challenge is to predict the shape deviation in the horizontal channel. This paper studies the geometric fidelity (roundness and shape deviation) of L-PBF printed horizontal interior circular channels (diameters 1−3 mm) by developing experiment-based regression models and a preliminary computational fluid dynamics (CFD) simulation model. The roundness error is found to be affected by the shape/size of the melt pool, thermal stresses, beam offset, and the slicing algorithm. It is recommended that to decrease the roundness error, in addition to choosing a proper beam offset, the width/depth of the melt pool should be minimized by minimizing the volumetric energy density (smaller laser power or higher scanning speed). Shape deviation in overhanging structures is determined by the thermo-mechanical driven molten flow in the melt pool. Hanging structures with irregular profiles (dross) are formed due to the sinking of the melt pool on an unconsolidated powder bed under the effect of gravity, surface tension, and poor thermal conductivity. (Partially) unmelted powder randomly adheres to the edges of the melt pool enlarging the hanging structure and roughening the profile. Small laser power or large scanning speed benefits reducing the roundness error and hang-diameter ratio. 0° or 45° rotational linear scanning strategy can be selected for minimizing the roundness error or the hang-diameter ratio, respectively

Real-world evidence of the effects of sodium-glucose co-transporter 2 inhibitors on the dosing of diuretics in patients with heart failure: a retrospective cohort study

Background: Heart failure (HF) was estimated to impact approximately 64 million individuals worldwide in 2017 and is predicted to rise in the coming years. Therefore, the aim of our study was to evaluate the effects of sodium-glucose transport protein 2 (SGLT2) inhibitors on the dosing of diuretics among individuals diagnosed with HF.Methods: A retrospective cohort study was conducted at Security Forces Hospital in Riyadh, Saudi Arabia, between January 2018 and August 2022. The study included adult patients who were diagnosed with heart failure and received dapagliflozin and/or diuretic. A descriptive analysis was conducted to identify significant differences between both groups by using the chi-square test for categorical variables and the Student’s t-test for continuous variables. A logistic regression model was also run to identify the odds of each event. Statistical significance was indicated by p values less than .05.Results: Overall reduction in diuretics was reported in 68 patients in the SGLT2 inhibitors plus diuretic therapy group, while in the diuretic therapy group 25 patients reported overall reduction in diuretics (OR = 4.81, 95% [2.74–8.45]). The reduction of the loop dose level was reported by 58 patients in the SGLT2 inhibitors plus diuretic group and by 25 patients in the diuretic group (OR = 3.48, 95% [1.98–6.11]). The discontinuation of thiazide was reported by 16 patients in the SGLT2 inhibitors plus diuretic therapy group, but by only two patients in the diuretic group (OR = 9.04, 95% [2.03–40.19]). After 6 months, ejection fraction was increased by 2.74 in the SGLT2 inhibitors plus diuretic group (p = .0019) and decreased by 2.56 in the diuretic group (p = .0485), both of which were statistically significant. The mean dose changes were decreased by 14.52 in the SGLT2 inhibitors plus diuretic group (p < .0001), which was statistically significant.Conclusion: Treatment with SGLT2 inhibitors plus diuretic significantly reduced the patients’ diuretic requirements. Therefore, our finding supports the theoretical concept of minimizing the level of diuretic upon the initiation of SGLT2 inhibitors