Tunable optical nanocavity of iron-garnet with a buried metal layer

We report on the fabrication and characterization of a novel magnetophotonic structure designed as iron garnet based magneto-optical nanoresonator cavity constrained by two noble metal mirrors. Since the iron garnet layer requires annealing at high temperatures, the fabrication process can be rather challenging. Special approaches for the protection of metal layers against oxidation and morphological changes along with a special plasma-assisted polishing of the iron garnet layer surface were used to achieve a 10-fold enhancement of the Faraday rotation angle (up to 10.8°=μm) within a special resonance peak of 12 nm (FWHM) linewidth at a wavelength of 772 nm, in the case of a resonator with two silver mirrors. These structures are promising for tunable nanophotonics applications, in particular, they can be used as magneto-optical (MO) metal-insulator-metal waveguides and modulators

Evolution of Mechanical Twinning during Cyclic deformation of Mg-Zn-Ca Alloys

The present study clarifies the complex interplay between mechanical twinning and dislocation slip during low-cycle fatigue testing of Mg-Zn-Ca alloys. Temporal details of these mechanisms are studied non-destructively by in situ monitoring of the acoustic emission (AE) response powered by a robust signal categorization. Through the analysis of AE time series, the kinetics of deformation twinning per cycle and the overall accumulation of twinning during cyclic loading is described and its effect on fatigue life is highlighted

Fatigue Performance of Mg-Zn-Zr Alloy Processed by Hot Severe Plastic Deformation

Fatigue properties under axisymmetric push-pull loading of a magnesium alloy Mg-6Zn-0.5Zr (ZK60) after processing by multiaxial isothermal forging (MIF) to a total strain of 4.2 at 400 °C were investigated. The strong influence of the microstructure on the mechanical behavior is demonstrated. Hot severe plastic deformation was shown effective in improving the fatigue life in both the high- and low-cyclic regimes

Economic evaluation and analysis of the budget effect of the measuring of fractional flow reserve in Bulgaria

Въведение: Частичният (фракциониран) резерв на кръвотока (FFR) представлява съотношението на максималния миокарден кръвоток в случай на патологично променена артерия и максималния миокарден кръвоток, ако същата артерия е нормална. Цел: Целта на настоящата статия е да се направи икономическа оценка и анализ на бюджетното въздействие на медицинската дейност по измерване на фракционирания резерв на кръвотока при приложението ѝ в локална среда в България. Материал и методи: За целите на анализа са разработени два модела с помощта на Microsoft Excel и TreeAge Pro, оценяващи разходната ефективност на FFR-базирана перкутанна коронарна интервенция (PCI) спрямо PCI с класическата ангиографскибазирана стратегия при пациенти с исхемична болест на сърцето (ИБС) с една функционално-сигнификантна стеноза и при пациенти с многоклонова ИБС. Анализът използва здравна перспектива и гледна точка на платеца – НЗОК. Резултати: Mедикодиагностичната дейност FFR при пациенти с многоклонова коронарна болест се определя като разходно ефективен терапевтичен подход спрямо ангиографски-базираната PCI (ICER = 50 455,71 лв./QALY) при праг от 51 510 лв./QALY. FFR-базираната стратегия за PCI при пациенти с една функционално-сигнификантна стеноза e разход-спестяващ подход (-853 лв. на пациент) спрямо ангиографски-базираната стратегия за PCI (съответно 3297 лв. спрямо 4150 лв.). Заключение: Анализът на бюджетното въздействие показва, че FFR-базираната стратегия за PCI е разход-спестяваща алтернатива на ангиографскибазираната стратегия. Спестяванията за НЗОК през първата година от реимбурсирането на FFR са -1,1 млн. лв. и достигат до -1,6 млн. лв. през третата година. Introduction: Fractional fl ow reserve (FFR) implies the ratio of the maximal hyperemic myocardial blood fl ow in the case of a pathologically changed coronary artery to the maximal hyperemic myocardial blood fl ow in the case of a healthy coronary artery. Aims: The aim of the current study is to perform an economic evaluation and budget impact analysis of measuring FFR as a medical activity in Bulgaria. Material and Methods: For the purpose of the current analysis, two models using Microsoft Excel and TreeAge Pro were developed to evaluate the cost-effectiveness of the FFR-guided percutaneous coronary intervention (PCI) compared to the classic angiography-guided PCI in patients with ischemic heart disease (IHD) with one-vessel coronary artery disease (CAD) or multivessel CAD. The analysis will focus on the health perspective and the payer perspective - National Health Insurance Fund (NHIF). Results: The medico-diagnostic activity related to measuring FFR in patients with multi-vessel coronary artery disease is shown to be a cost-effective therapeutic approach in Bulgaria compared to the angiography-guided PCI (ICER = 50 456 BGN/QALY) with a cost-effectiveness threshold of 51 510 BGN/QALY. FFR- guided PCI strategy in one-vessel coronary artery disease patients is a cost-saving approach (-853 BGN) when compared to the angiography-guided PCI (4 150 BGN). Conclusion: Budget impact analysis revealed that the FFR-guided PCI strategy is a cost-saving alternative approach to the angiographyguided PCI. The savings of the NHIF during the fi rst year of reimbursement of FFR would be -1,1 million BGN and could reach -1,6 million BGN in the third year

High Performance Fine-Grained Biodegradable Mg-Zn-Ca Alloys Processed by Severe Plastic Deformation

The tensile strength, fatigue, and corrosion fatigue performance of the magnesium alloy ZX40 benefit strongly from hybrid deformation processing involving warm equal-channel angular pressing (ECAP) at the first step and room temperature rotary swaging at the second. The general corrosion resistance improved as well, though to a lesser extent. The observed strengthening is associated with a combined effect of substantial microstructure refinement down to the nanoscale, reducing deformation twinning activity, dislocation accumulation, and texture transformation. The ultimate tensile strength and the endurance limit in the ultrafine-grained material reached or exceeded 380 and 120 MPa, respectively, which are remarkable values for this nominally low strength alloy

High Performance Fine-Grained Biodegradable Mg-Zn-Ca Alloys Processed by Severe Plastic Deformation

The tensile strength, fatigue, and corrosion fatigue performance of the magnesium alloy ZX40 benefit strongly from hybrid deformation processing involving warm equal-channel angular pressing (ECAP) at the first step and room temperature rotary swaging at the second. The general corrosion resistance improved as well, though to a lesser extent. The observed strengthening is associated with a combined effect of substantial microstructure refinement down to the nanoscale, reducing deformation twinning activity, dislocation accumulation, and texture transformation. The ultimate tensile strength and the endurance limit in the ultrafine-grained material reached or exceeded 380 and 120 MPa, respectively, which are remarkable values for this nominally low strength alloy

High strength and fatigue properties of Mg-Zn-Ca alloys after severe plastic deformation

Magnesium alloys are the lightest metallic structural materials with an outstanding specific strength. This makes them appealing for a wide range of applications in “green” transportation where weight saving is of major concern. Another emerging application area for modern Mg-based alloys is in the biomedical domain where they are considered as bioabsorbable temporary implants, and where the worldwide market is expanding particularly rapidly in parallel with the surging research. Requirements for mechanical properties - strength, ductility and fatigue resistance - of implants in orthopaedics are stringent. Therefore, a broad variety of processing routes have been proposed in the past decade to tailor the microstructure in order to optimize the properties. In the present brief communication, we demonstrate that using a hybrid deformation processing schedule involving warm equal-channel angular pressing (ECAP) on the first stage and cold rotary swaging on the second dramatically improves the tensile and fatigue properties of the magnesium alloy ZX40. Due to a combined effect of significant grain refinement and dislocation storage after rotary swaging, the ultimate tensile strength and the conventional fatigue limit achieved very high values (for this class of alloys) of 380 MPa and 115 MPa, respectively. Preliminary results of the microstructural investigations are discussed briefly