Mechanical And Electrical Properties Of Short Carbon Fibre Reinforced Polycarbonate Composites

A series of composites was prepared using polycarbonate (PC) as the matrix, reinforced with short carbon fibre (SCF) at different weight fractions. The composites were compounded by single screw extruder and specimens were prepared by injection moulding machine. The effect of fibre weight fractions on the mechanical and electrical properties of SCF reinforced polycarbonate composite was studied. The test specimens were fabricated in accordance to the ASTM specifications. The mechanical properties of the composites were characterized by tensile, flexural and fracture toughness tests, while the morphological properties were characterized by scanning electron microscope (SEM). In addition, electrical properties were evaluated by surface resistivity test. Cox-Krenchel and rule of mixtures (RoM) were used to predict theoretical tensile moduli of the composites. Experiment results revealed that density of the composites increased with the addition of SCF. Fibre length was found to be greatly reduced during processing the of composites. Higher mean fibre length tends to provide better reinforcement effect, thus enhanced mechanical properties. Incorporation of SCF improved the strength of the composite, and the effect was more prominent at higher weight fraction of SCF. With increasing SCF content, the surface resistivity reduced drastically with the percolation threshold lie in between 10% - 14% of SCF weight fraction. Cox-Krenchel model showed to be a good approximation to predict the composites’ tensile modulus. 14% SCF reinforced PC composite which was obtained from commercial compound proved the effective extrusion compounding of these self-compounded composites (5%, 10% and 15% SCF), by possessing intermediate properties in between 10% and 15% SCF reinforced PC composites as expected

Epidemiology and outcomes of hospital-acquired bloodstream infections in intensive care unit patients: the EUROBACT-2 international cohort study

Purpose In the critically ill, hospital-acquired bloodstream infections (HA-BSI) are associated with significant mortality. Granular data are required for optimizing management, and developing guidelines and clinical trials. Methods We carried out a prospective international cohort study of adult patients (≥ 18 years of age) with HA-BSI treated in intensive care units (ICUs) between June 2019 and February 2021. Results 2600 patients from 333 ICUs in 52 countries were included. 78% HA-BSI were ICU-acquired. Median Sequential Organ Failure Assessment (SOFA) score was 8 [IQR 5; 11] at HA-BSI diagnosis. Most frequent sources of infection included pneumonia (26.7%) and intravascular catheters (26.4%). Most frequent pathogens were Gram-negative bacteria (59.0%), predominantly Klebsiella spp. (27.9%), Acinetobacter spp. (20.3%), Escherichia coli (15.8%), and Pseudomonas spp. (14.3%). Carbapenem resistance was present in 37.8%, 84.6%, 7.4%, and 33.2%, respectively. Difficult-to-treat resistance (DTR) was present in 23.5% and pan-drug resistance in 1.5%. Antimicrobial therapy was deemed adequate within 24 h for 51.5%. Antimicrobial resistance was associated with longer delays to adequate antimicrobial therapy. Source control was needed in 52.5% but not achieved in 18.2%. Mortality was 37.1%, and only 16.1% had been discharged alive from hospital by day-28. Conclusions HA-BSI was frequently caused by Gram-negative, carbapenem-resistant and DTR pathogens. Antimicrobial resistance led to delays in adequate antimicrobial therapy. Mortality was high, and at day-28 only a minority of the patients were discharged alive from the hospital. Prevention of antimicrobial resistance and focusing on adequate antimicrobial therapy and source control are important to optimize patient management and outcomes