Sheathed cold-formed steel wall systems

Cold-formed steel members are widely used in the construction industry due to their versatility, high strength-to-weight ratio and ease of assembly. Stud columns set in tracks, form the main members in cold-formed steel wall systems, which are typically sheathed with plasterboard or oriented strand board (OSB). The interaction between the cold-formed steel members and the sheathing, which can have a significant effect on the ultimate strength and flexural stiffness due to composite action and bracing, is currently not systematically taken into consideration in design. More than 100 material and connection component tests have been performed to study the behaviour of plasterboard and OSB and their interconnection with cold-formed steel through screws acting in shear and tension. The obtained test results, along with a collected dataset totalling more than 400 physical tests, were used to develop analytical models to describe their load-deformation behaviour; these are suitable for use in numerical simulations and advanced design methods. A total of 17 full-scale sheathed wall stud tests were also performed, with varying connector spacing between either plasterboard or OSB sheathing panels and the steel members. Tests were performed under pure compression, pure bending and combined loading. Reducing the spacing of the connectors from 600 mm to 75 mm resulted in up to 30% increase in capacity while also preventing pull-through connector failure for specimens sheathed with plasterboard. Sophisticated finite element models of wall studs were also developed, which, following successful validation against test results, allowed parametric studies to be undertaken, where the influence of the sheathing, connector spacing and section depth was investigated. Finally, a preliminary design guidance has been developed, where the beneficial effects of bracing, composite action and enhanced boundary conditions at the member ends are recognised, thus enabling more efficient design of sheathed cold-formed steel wall systems.Open Acces

A New Method for Diaphragmatic Maximum Relaxation Rate Ultrasonographic Measurement in the Assessment of Patients With Diaphragmatic Dysfunction

Measurements of ultrasound diaphragmatic motion, amplitude, force, and velocity of contraction may provide important and essential information about diaphragmatic fatigue, weakness, or paralysis. In this paper, we propose and evaluate a semi-automated analysis system for measuring the diaphragmatic motion and estimating the maximum relaxation rate (MRR_SAUS) from ultrasound M-mode images of the diaphragmatic muscle. The system was evaluated on 27 M-mode ultrasound images of the diaphragmatic muscle [20 with no resistance (NRES) and 7 with resistance (RES)]. We computed semi-automated ultrasound MRR measurements on all NRES/RES images, using the proposed system (MRR_SAUS = 3.94 ± 0.91/4.98 ± 1.98 [1/s]), and compared them with the manual measurements made by a clinical expert (MRR_MUS = 2.36 ± 1.19/5.8 ± 2.1 [1/s],) and those made by a reference manual method (MRR_MB = 3.93 ± 0.89/3.73 ± 0.52 [1/sec], performed manually with the Biopac system. MRR_SAUS and MRR_MB measurements were not statistically significantly different for NRES and RES subjects but were significantly different with the MRR-MUS measurements made by the clinical expert. It is anticipated that the proposed system might be used in the future in the clinical practice in the assessment and follow up of patients with diaphragmatic weakness or paralysis. It may thus potentially help to understand post-operative pulmonary dysfunction or weaning failure from mechanical ventilation. Further validation and additional experimentation in a larger sample of images and different patient groups is required for further validating the proposed system

Extensive testing and public health interventions for the control of covid-19 in the republic of cyprus between march and may 2020

Coronavirus disease 2019 (COVID-19) has significantly affected the well-being of individuals worldwide. We herein describe the epidemiology of COVID-19 in the Republic of Cyprus during the first epidemic wave (9 March–3 May 2020). We analyzed surveillance data from laboratory-confirmed cases, including targeted testing and population screening. Statistical analyses included logistic regression. During the surveillance period, 64,136 tests (7322.3 per 100,000) were performed, 873 COVID-19 cases were diagnosed, and 20 deaths were reported (2.3%). Health-care workers (HCWs) represented 21.4% of cases. Overall, 19.1% of cases received hospital care and 3.7% required admission to Intensive Care Units. Male sex (adjusted Odds Ratio (aOR): 3.04; 95% Confidence Interval (CI): 1.97–4.69), increasing age (aOR: 1.56; 95%CI: 1.36–1.79), symptoms at diagnosis (aOR: 6.05; 95%CI: 3.18–11.50), and underlying health conditions (aOR: 2.08; 95%CI: 1.31–3.31) were associated with hospitalization. For recovered cases, the median time from first to last second negative test was 21 days. Overall, 119 primary cases reported 616 close contacts, yielding a pooled secondary attack rate of 12% (95%CI: 9.6–14.8%). Three population-based screening projects, and two projects targeting employees and HCWs, involving 25,496 people, revealed 60 positive individuals (0.2%). Early implementation of interventions with targeted and expanded testing facilitated prompt outbreak control on the island