Effect of process parameters on the microstructure and mechanical properties of AA2024 fabricated using selective laser melting

Selective laser melting (SLM) offers significant benefits, including geometric freedom and rapid production, when compared with traditional manufacturing techniques. However, the materials available for SLM production remain limited, restricting the industrial adoption of the technology. The mechanical properties and microstructure of many aluminium alloys have not been fully explored, as their manufacturability using SLM is extremely challenging. This study investigates the effect of laser power, hatch spacing and scanning speed on the mechanical and microstructural properties of as-fabricated aluminium 2024 alloy (AA2024) manufactured using SLM. The results reveal that almost crack-free structures with high relative density (99.9%) and Archimedes density (99.7%) have been achieved. It is shown that when using low energy density (ED) levels, large cracks and porosities are a major problem, owing to incomplete fusion; however, small gas pores are prevalent at high-energy densities due to the dissolved gas particles in the melt pool. An inversely proportional relationship between ED and microhardness has also been observed. Lower ED decreases the melt pool size and temperature gradients but increases the cooling rate, creating a fine-grained microstructure, which restricts dislocation movement, therefore increasing the microhardness. The highest microhardness (116 HV0.2), which was obtained from one of the lowest EDs used (100 J/mm3), is 45% higher than as-cast AA2024-0, but 17% lower than wrought AA2024-T6 alloy

International multicentre study of candida auris infections

Background: Candida auris has emerged globally as a multi-drug resistant yeast and is commonly associated with nosocomial outbreaks in ICUs. Methods: We conducted a retrospective observational multicentre study to determine the epidemiology of C. auris infections, its management strategies, patient outcomes, and infection prevention and control practices across 10 centres from five countries. Results: Significant risk factors for C. auris infection include the age group of 61–70 years (39%), recent history of ICU admission (63%), diabetes (63%), renal failure (52%), presence of CVC (91%) and previous history of antibiotic treatment (96%). C. auris was commonly isolated from blood (76%). Echinocandins were the most sensitive drugs. Most common antifungals used for treatment were caspofungin (40%), anidulafungin (28%) and micafungin (15%). The median duration of treatment was 20 days. Source removal was conductedin 74% patients. All-cause crude mortality rate after 30 days was 37%. Antifungal therapy was associated with a reduction in mortality (OR:0.27) and so was source removal (OR:0.74). Contact isolation precautions were followed in 87% patients. Conclusions: C. auris infection carries a high risk for associated mortality. The organism is mainly resistant to most azoles and even amphotericin-B. Targeted antifungal therapy, mainly an echinocandin, and source control are the prominent therapeutic approaches

Liver involvement in patients with brucellosis: results of the Marmara study

Brucellosis is a zoonotic disease that primarily affects the reticuloendothelial system. But, the extent of liver damage in due course of the disease is unclear. This study included 325 brucellosis patients with significant hepatobiliary involvement identified with microbiological analyses from 30 centers between 2000 and 2013. The patients with a parts per thousand yen5 times of the upper limit of normal for aminotransferases, total bilirubin level a parts per thousand yen2 mg/dl or local liver lesions were enrolled. Clinical hepatitis was detected in 284 patients (87.3 %) and cholestasis was detected in 215 (66.1 %) patients. Fatigue (91 %), fever (86 %), sweating (83 %), arthralgia (79 %), and lack of appetite (79 %) were the major symptoms. Laboratory tests showed anemia in 169 (52 %), thrombocytopenia in 117 (36 %), leukopenia in 81 (25 %), pancytopenia in 42 (13 %), and leukocytosis in 20 (6 %) patients. The most commonly used antibiotic combinations were doxycycline plus an aminoglycoside (n = 73), doxycycline plus rifampicin (n = 71), doxycycline plus rifampicin and an aminoglycoside (n = 27). The duration of ALT normalization differed significantly in three treatment groups (p 0.05). During the follow-up, treatment failure occurred in four patients (1 %) and relapse was seen in three patients (0.9 %). Mortality was not observed. Hepatobiliary involvement in brucellosis has a benign course with suitable antibiotics and the use of doxycycline and an aminoglycoside regimen seems a better strategy in select patients.https://doi.org/10.1007/s10096-014-2064-

Factors leading to dissemination of cutaneous anthrax: an international ID-IRI study

Background: Although anthrax is a rare zoonotic infection, it still causes significant mortality and morbidity. In this multicenter study, which is the largest anthrax case series ever reported, we aimed to describe the factors leading to dissemination of cutaneous anthrax.Methods: Adult patients with cutaneous anthrax from 16 referral centers were pooled. The study had a retrospective design, and included patients treated between January 1, 1990 and December 1, 2019. Probable, and confirmed cases based upon CDC anthrax 2018 case definition were included in the study. A descriptive statistical analysis was performed for all variables.Results: A total of 141 cutaneous anthrax patients were included. Of these, 105 (74%) patients had probable and 36 (26%) had confirmed diagnosis. Anthrax meningitis and bacteremia occurred in three and six patients, respectively. Sequelae were observed in three patients: cicatricial ectropion followed by ocular anthrax (n = 2) and movement restriction on the left hand after surgical intervention (n = 1). One patient had gastrointestinal anthrax. The parameters related to poor outcome (p < 0.05) were fever, anorexia, hypoxia, malaise/fatigue, cellulitis, fasciitis, lymphadenopathy, leukocytosis, high CRP and creatinine levels, longer duration of antimicrobial therapy, and combined therapy. The last two were seemingly the consequences of dissemination rather than being the reasons. The fatality rate was 1.4%.Conclusions: Rapid identification of anthrax is crucial for prompt and effective treatment. Systemic symptoms, disseminated local infection, and high inflammatory markers should alert the treating physicians for the dissemination of the disease. (c) 2022 The Authors. Published by Elsevier Ltd

Managing atypical and typical herpetic central nervous system infections: results of a multinational study

There have been many studies pertaining to the management of herpetic meningoencephalitis (HME), but the majority of them have focussed on virologically unconfirmed cases or included only small sample sizes. We have conducted a multicentre study aimed at providing management strategies for HME. Overall, 501 adult patients with PCR-proven HME were included retrospectively from 35 referral centres in 10 countries; 496 patients were found to be eligible for the analysis. Cerebrospinal fluid (CSF) analysis using a PCR assay yielded herpes simplex virus (HSV)-1 DNA in 351 patients (70.8%), HSV-2 DNA in 83 patients (16.7%) and undefined HSV DNA type in 62 patients (12.5%). A total of 379 patients (76.4%) had at least one of the specified characteristics of encephalitis, and we placed these patients into the encephalitis presentation group. The remaining 117 patients (23.6%) had none of these findings, and these patients were placed in the nonencephalitis presentation group. Abnormalities suggestive of encephalitis were detected in magnetic resonance imaging (MRI) in 83.9% of the patients and in electroencephalography (EEG) in 91.0% of patients in the encephalitis presentation group. In the nonencephalitis presentation group, MRI and EEG data were suggestive of encephalitis in 33.3 and 61.9% of patients, respectively. However, the concomitant use of MRI and EEG indicated encephalitis in 96.3 and 87.5% of the cases with and without encephalitic clinical presentation, respectively. Considering the subtle nature of HME, CSF HSV PCR, EEG and MRI data should be collected for all patients with a central nervous system infection. (C) 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved

Liver involvement in patients with brucellosis: results of the Marmara study

WOS: 000336986700024PubMed ID: 24557334Brucellosis is a zoonotic disease that primarily affects the reticuloendothelial system. But, the extent of liver damage in due course of the disease is unclear. This study included 325 brucellosis patients with significant hepatobiliary involvement identified with microbiological analyses from 30 centers between 2000 and 2013. The patients with a parts per thousand yen5 times of the upper limit of normal for aminotransferases, total bilirubin level a parts per thousand yen2 mg/dl or local liver lesions were enrolled. Clinical hepatitis was detected in 284 patients (87.3 %) and cholestasis was detected in 215 (66.1 %) patients. Fatigue (91 %), fever (86 %), sweating (83 %), arthralgia (79 %), and lack of appetite (79 %) were the major symptoms. Laboratory tests showed anemia in 169 (52 %), thrombocytopenia in 117 (36 %), leukopenia in 81 (25 %), pancytopenia in 42 (13 %), and leukocytosis in 20 (6 %) patients. The most commonly used antibiotic combinations were doxycycline plus an aminoglycoside (n = 73), doxycycline plus rifampicin (n = 71), doxycycline plus rifampicin and an aminoglycoside (n = 27). The duration of ALT normalization differed significantly in three treatment groups (p 0.05). During the follow-up, treatment failure occurred in four patients (1 %) and relapse was seen in three patients (0.9 %). Mortality was not observed. Hepatobiliary involvement in brucellosis has a benign course with suitable antibiotics and the use of doxycycline and an aminoglycoside regimen seems a better strategy in select patients

Cranial imaging findings in neurobrucellosis: results of Istanbul-3 study.

OBJECTIVE: Neuroimaging abnormalities in central nervous system (CNS) brucellosis are not well documented. The purpose of this study was to evaluate the prevalence of imaging abnormalities in neurobrucellosis and to identify factors associated with leptomeningeal and basal enhancement, which frequently results in unfavorable outcomes. METHODS: Istanbul-3 study evaluated 263 adult patients with CNS brucellosis from 26 referral centers and reviewed their 242 magnetic resonance imaging (MRI) and 226 computerized tomography (CT) scans of the brain. RESULTS: A normal CT or MRI scan was seen in 143 of 263 patients (54.3 %). Abnormal imaging findings were grouped into the following four categories: (a) inflammatory findings: leptomeningeal involvements (44), basal meningeal enhancements (30), cranial nerve involvements (14), spinal nerve roots enhancement (8), brain abscesses (7), granulomas (6), and arachnoiditis (4). (b) White-matter involvement: white-matter involvement (32) with or without demyelinating lesions (7). (c) Vascular involvement: vascular involvement (42) mostly with chronic cerebral ischemic changes (37). (d) Hydrocephalus/cerebral edema: hydrocephalus (20) and brain edema (40). On multivariate logistic regression analysis duration of symptoms since the onset (OR 1.007; 95 % CI 1-28, p = 0.01), polyneuropathy and radiculopathy (OR 5.4; 95 % CI 1.002-1.013, p = 0.044), cerebrospinal fluid (CSF)/serum glucose rate (OR 0.001; 95 % CI 000-0.067, p = 0.001), and CSF protein (OR 2.5; 95 % CI 2.3-2.7, p = 0.0001) were associated with diffuse inflammation. CONCLUSIONS: In this study, 45 % of neurobrucellosis patients had abnormal neuroimaging findings. The duration of symptoms, polyneuropathy and radiculopathy, high CSF protein level, and low CSF/serum glucose rate were associated with inflammatory findings on imaging analyses

Cranial imaging findings in neurobrucellosis: results of Istanbul-3 study

Objective: Neuroimaging abnormalities in central nervous system (CNS) brucellosis are not well documented. The purpose of this study was to evaluate the prevalence of imaging abnormalities in neurobrucellosis and to identify factors associated with leptomeningeal and basal enhancement, which frequently results in unfavorable outcomes. Methods: Istanbul-3 study evaluated 263 adult patients with CNS brucellosis from 26 referral centers and reviewed their 242 magnetic resonance imaging (MRI) and 226 computerized tomography (CT) scans of the brain. Results: A normal CT or MRI scan was seen in 143 of 263 patients (54.3 %). Abnormal imaging findings were grouped into the following four categories: (a) inflammatory findings: leptomeningeal involvements (44), basal meningeal enhancements (30), cranial nerve involvements (14), spinal nerve roots enhancement (8), brain abscesses (7), granulomas (6), and arachnoiditis (4). (b) White-matter involvement: white-matter involvement (32) with or without demyelinating lesions (7). (c) Vascular involvement: vascular involvement (42) mostly with chronic cerebral ischemic changes (37). (d) Hydrocephalus/cerebral edema: hydrocephalus (20) and brain edema (40). On multivariate logistic regression analysis duration of symptoms since the onset (OR 1.007; 95 % CI 1–28, p = 0.01), polyneuropathy and radiculopathy (OR 5.4; 95 % CI 1.002–1.013, p = 0.044), cerebrospinal fluid (CSF)/serum glucose rate (OR 0.001; 95 % CI 000–0.067, p = 0.001), and CSF protein (OR 2.5; 95 % CI 2.3–2.7, p = 0.0001) were associated with diffuse inflammation. Conclusions: In this study, 45 % of neurobrucellosis patients had abnormal neuroimaging findings. The duration of symptoms, polyneuropathy and radiculopathy, high CSF protein level, and low CSF/serum glucose rate were associated with inflammatory findings on imaging analyses. © 2016, Springer-Verlag Berlin Heidelberg

Portraying infective endocarditis: results of multinational ID-IRI study

Infective endocarditis is a growing problem with many shifts due to ever-increasing comorbid illnesses, invasive procedures, and increase in the elderly. We performed this multinational study to depict definite infective endocarditis. Adult patients with definite endocarditis hospitalized between January 1, 2015, and October 1, 2018, were included from 41 hospitals in 13 countries. We included microbiological features, types and severity of the disease, complications, but excluded therapeutic parameters. A total of 867 patients were included. A total of 631 (72.8%) patients had native valve endocarditis (NVE), 214 (24.7%) patients had prosthetic valve endocarditis (PVE), 21 (2.4%) patients had pacemaker lead endocarditis, and 1 patient had catheter port endocarditis. Eighteen percent of NVE patients were hospital-acquired. PVE patients were classified as early-onset in 24.9%. A total of 385 (44.4%) patients had major embolic events, most frequently to the brain (n = 227, 26.3%). Blood cultures yielded pathogens in 766 (88.4%). In 101 (11.6%) patients, blood cultures were negative. Molecular testing of vegetations disclosed pathogens in 65 cases. Overall, 795 (91.7%) endocarditis patients had any identified pathogen. Leading pathogens (Staphylococcus aureus (n = 267, 33.6%), Streptococcus viridans (n = 149, 18.7%), enterococci (n = 128, 16.1%), coagulase-negative staphylococci (n = 92, 11.6%)) displayed substantial resistance profiles. A total of 132 (15.2%) patients had cardiac abscesses; 693 (79.9%) patients had left-sided endocarditis. Aortic (n = 394, 45.4%) and mitral valves (n = 369, 42.5%) were most frequently involved. Mortality was more common in PVE than NVE (NVE (n = 101, 16%), PVE (n = 49, 22.9%), p = 0.042)