Developers of metamaterial-based devices in our dais face a serious problem-they can guess the properties of metamaterial itself only by analyzing the overall parameters of the complete device. As such constructions are periodical metal-dielectric structures, the standard methods of their permittivity and permeability measurement cannot be implemented. In this paper a methodology of metamaterial effective permittivity and permeability determination, based on their complex reflecting and transmitting coefficient measurement, is suggested. The base of the presented algorithm is evaluations, shown here, which determine the dependence of dielectric parameters of the sample under test on its measured S-parameters. For practical measurement some constructions of measuring tools, which allow metamaterial parameter determination in case of using longitudinal electromagnetic wave with vertical and horizontal polarization of electric field and normally incident wave, are suggested. A form of realization and a band, in which measurements can be provided, are presented for each type of measuring tools. An advantage of all constructions is that they are closed structures and do not feel the influence of surroundings. The schema of connecting the measuring tools to a vector network analyzer is detail reviewed. A question of measuring schema element influence on the accuracy of parameter determination is discussed separately. As the constructions of measuring tools do not allow direct measuring device calibration, a method of compensation of their influence on the measured parameters accuracy, based on the mathematical processing of the obtained data, is suggested. Practical results of metamaterial sample effective permittivity and permeability determination, made using the described algorithm and two different measuring tools, are shown. The made experiment has shown a good correlation of the obtained data between each other and with the computed parameters of the sample. So the paper presents the detailed description of the methodology of metamaterial effective permittivity and permeability determination, with the help of measuring their complex reflecting and transmitting coefficient, some measuring tool constructions are suggested, which allow practical measurements, measuring circuit calibration methods are described. The presented experimental data confirm that the suggested algorithm can be used.

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Background: Central line-associated bloodstream infections (CLABSI) in the intensive care unit (ICU) are a serious preventable hospital acquired infection which can result in increasing mortality, morbidity and health care costs. In this study, we aim to determine the effect of implementing a multimodal strategy on reducing the incidence rates of CLABSIs in the ICU of a tertiary teaching hospital.Methods and materials: All patients who had a central venous catheter (CVC) inserted in in the University Malaya Medical Centre (UMMC) ICU from January 2018 to June 2019 were prospectively followed up by the infection control nurse until removal of CVC. The study periods were divided into pre-intervention (January 2018-August 2018) and the post intervention (September 2018-August 2019) periods. CLABSI was diagnosed based on the definition by Centers for Disease Control and Prevention (CDC). Data was collected using a standardized CLABSI surveillance form and analyzed using Statistical Package for the Social Sciences (SPSS) version 20. In September 2018, a multidisciplinary quality improvement team was formed consisting of interventionists, the infection control team, an infectious diseases physician, ICU nurses and medical assistants. A baseline assessment of current practice was done and gaps in practice were identified. Following that, the team carried out several interventions including education, training, regular audits on line care, immediate feedback and conducting mini root cause analysis for every CLABSI identified. Additionally all staff in ICU were required to complete the online Hand Hygiene Australia module.Results: In the pre intervention period, the rate of CLABSI in ICU was high at 8.89/1000 catheter days. Following the multimodal interventions in September 2018, the rates of CLABSI in ICU reduced to 3.02/1000 catheter days in the post intervention period. Conclusion:Implementing multimodal strategies with a multidisciplinary team in the ICU with hands on training, and regular audits is effective in reducing the incidence rates of CLABSI.

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