Aging Time Effects on the Mechanical Properties of Al 6061-T6 Alloy

This work investigates the influence of artificial aging and solution heat treatment on the hardness and tensile strength (mechanical properties) of Al 6061-T6 alloy. For this investigation, several aluminum 6061-T6 alloy specimens were prepared following the ASTM 176000 recommendations. The prepared specimens were heated for 1 hour at 500ºC before being water-quenched. The procedure for artificial aging was performed for 1, 2, 3, and 4 hours at 190ºC before being slowly cooled in air. Several mechanical and characterization studies were performed on the treated specimens, including an investigation on their microstructure, tensile strength, hardness, and X-ray diffraction pattern. From the results, the strength and hardness properties of the specimens were found to be generally improved, even as the best features were obtained after 2 hours of artificial aging

Chromobacterium violaceum in Siblings, Brazil

Chromobacterium violaceum, a saprophyte bacterium found commonly in soil and water in tropical and subtropical climates, is a rare cause of severe, often fatal, human disease. We report 1 confirmed and 2 suspected cases of C. violaceum septicemia, with 2 fatalities, in siblings after recreational exposure in northeastern Brazil

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Arthroscopic treatment of septic arthritis of the hip

Arthrotomy is considered standard treatment for septic arthritis of the hip; the procedure may be complicated by avascular necrosis or postoperative hip instability. Arthroscopic treatment of patients with this condition is still not an established technique, despite its minimally invasive nature and the fact that it is associated with low morbidity. A 3-portal arthroscopic technique by Byrd with the patient in the supine position was used for drainage, debridement, and irrigation in 6 patients with septic coxarthrosis. Continuous postoperative intra-articular irrigation was not provided, nor were postoperative decompression drains used. All patients were treated with intravenous antibiotics for 3 weeks, followed by oral antibiotics for an additional minimum of 3 weeks. Patients were followed for 6 to 42 months. Staphylococcus aureus was identified in 4 of the 6 patients. All patients had a rapid postoperative recovery. Mean Harris Hip Score at the last review was 97.5 points. All patients showed full range of motion of the affected hip. No complications occurred with this group of patients. Thus, 3-directional arthroscopic surgery combined with large-volume irrigation is an effective treatment modality in cases of septic arthritis of the hip. It is less invasive than arthrotomy and offers low rates of postsurgical morbidity. © 2006 Arthroscopy Association of North America

In Vitro Analysis of Antifungal Impregnated Polymethylmethacrylate Bone Cement

Fungal infection of total joint arthroplasty is a rare but devastating complication. This study examines the change in mechanical properties of cement with the inclusion of variable concentrations of Amphotericin B antifungal and the elution rate from the polymerised cement