On-chip spatiotemporal optical vortex generation using an integrated metal-dielectric resonator

We theoretically demonstrate the possibility of generating a spatiotemporal optical vortex (STOV) beam in a dielectric slab waveguide. The STOV is generated upon reflection of a spatiotemporal optical pulse from an integrated metal-dielectric structure consisting of metal strips "buried" in the waveguide. For describing the interaction of the incident pulse with the integrated structure, we derive its "vectorial" spatiotemporal transfer function (TF) describing the transformation of the electromagnetic field components of the incident pulse. We show that if the TF of the structure corresponds to the TF of a spatiotemporal differentiator with a $\pi/2$ phase difference between the terms describing temporal and spatial differentiation, then the envelope of the reflected pulse will contain an STOV in all nonzero components of the electromagnetic field. The obtained theoretical results are in good agreement with the results of rigorous numerical simulation of the STOV generation using a three-strip metal-dielectric integrated structure. We believe that the presented results pave the way for the research and application of STOV beams in the on-chip geometry.Comment: 14 pages, 5 figure

Coupled FEM-DBEM method to assess crack growth in magnet system of Wendelstein 7-X

The fivefold symmetric modular stellarator Wendelstein 7-X (W7-X) is currently under construction in Greifswald, Germany. The superconducting coils of the magnet system are bolted onto a central support ring and interconnected with five so-called lateral support elements (LSEs) per half module. After welding of the LSE hollow boxes to the coil cases, cracks were found in the vicinity of the welds that could potentially limit the allowed number N of electromagnetic (EM) load cycles of the machine. In response to the appearance of first cracks during assembly, the Stress Intensity Factors (SIFs) were calculated and corresponding crack growth rates of theoretical semi-circular cracks of measured sizes in potentially critical position and orientation were predicted using Paris’ law, whose parameters were calibrated in fatigue tests at cryogenic temperature. In this paper the Dual Boundary Element Method (DBEM) is applied in a coupled FEM-DBEM approach to analyze the propagation of multiple cracks with different shapes. For this purpose, the crack path is assessed with the Minimum Strain Energy density criterion and SIFs are calculated by the Jintegral approach. The Finite Element Method (FEM) is adopted to model, using the commercial codes Ansys or Abaqus;, the overall component whereas the submodel analysis, in the volume surrounding the cracked area, is performed by FEM (“FEM-FEM approach”) or alternatively by DBEM (“FEM-DBEM approach”). The “FEM-FEM approach” considers a FEM submodel, that is extracted from the FEM global model; the latter provide the boundary conditions for the submodel. Such approach is affected by some restrictions in the crack propagation phase, whereas, with the “FEM-DBEM approach”, the crack propagation simulation is straightforward. In this case the submodel is created in a DBEM environment with boundary conditions provided by the global FEM analysis; then the crack is introduced and a crack propagation analysis has been performed to evaluate the effects of the crack shape and of the presence of nearby cracks on the allowed number of EM load cycles

СОВРЕМЕННАЯ ГЕОДИНАМИКА И СЕЙСМИЧНОСТЬ ДАЛЬНЕГО ВОСТОКА И ВОСТОЧНОЙ СИБИРИ

The information on the «Problems of seismicity and recent geodynamics of the Far East and Eastern Siberia» Symposium is presented. It was held on June 1–4, 2010 at the Yu.A. Kosygin Institute of tectonics and teophysics, Far Eastern branch, Russian academy of sciences, Khabarovsk. The scope of plenary meetings, sessions and round-table discussions conducted during the Symposium is presented with a brief review of the most interesting scientific reports.Представлена информация о симпозиуме «Проблемы сейсмичности и современной геодинамики Дальнего Востока и Восточной Сибири», проведенном 1–4 июня 2010 г. в Институте тектоники и геофизики им. Ю.А. Косыгина ДВО РАН (г. Хабаровск). Освещена тематика пленарных и секционных заседаний симпозиума, «круглых столов», дано краткое содержание отдельных наиболее интересных докладов

Physical-Mechanical Properties of γ-Irradiated SiC Ceramics for Radioactive Wastes Immobilization

The interest in silicon carbide (SiC-based) ceramics and composites as matrix material for nuclear waste immobilization is grown up. Long-term chemical durability and radiation resistance of SiC are important factors for radionuclides immobilization. Advantages of SiC-based ceramics as structural materials in nuclear applications are the high-temperature properties, high density and reduced neutron activation. The use of radiation resistant materials is a strong requirement for safe and environmentally beneficial energy system. The SiC ceramics stability under irradiation for temperatures up to 1273 K is also very important for nuclear power applications. The SiC matrices doped by additives of Cr, Si were fabricated using High Speed Hot Pressing Method. Additives content was in the range from 0.5 to 3 wt %. Microstructural characteristics of silicon carbide ceramics were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and infra-red spectroscopy (IR) methods. The results of microcracking under indentation conditions were revealed the lack of cracks in the SiC ceramics with Cr additives before and after irradiation process. In addition, it was demonstrated that samples of SiC with alloying additives Cr and Si possess high mechanical parameters under γ-irradiation process. The strength of ceramics increases with the uniform and fine-grained structure formation. The modification of phase composition and mechanical properties of the SiC ceramics with Cr and Si additives under γ-irradiation were analyzed for further development of radiation resistant and matrix materials for radioactive wastes immobilization

Multimodal optical measurement for study of lower limb tissue viability in patients with diabetes mellitus

According to the International Diabetes Federation, the challenge of early stage diagnosis and treatment effectiveness monitoring in diabetes is currently one of the highest priorities in modern healthcare. The potential of combined measurements of skin fluorescence and blood perfusion by the laser Doppler flowmetry method in diagnostics of low limb diabetes complications was evaluated. Using Monte Carlo probabilistic modeling, the diagnostic volume and depth of the diagnosis were evaluated. The experimental study involved 76 patients with type 2 diabetes mellitus. These patients were divided into two groups depending on the degree of complications. The control group consisted of 48 healthy volunteers. The local thermal stimulation was selected as a stimulus on the blood microcirculation system. The experimental studies have shown that diabetic patients have elevated values of normalized fluorescence amplitudes, as well as a lower perfusion response to local heating. In the group of people with diabetes with trophic ulcers, these parameters also significantly differ from the control and diabetes only groups. Thus, the intensity of skin fluorescence and level of tissue blood perfusion can act as markers for various degrees of complications from the beginning of diabetes to the formation of trophic ulcers

Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry

Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Single Vibroacoustic Impact Effect of Singing Bowls over the Psycho-Emotional State and Cardiovascular System Work

This article presents a two-stage study result of the author's method of vibroacoustic massage using singing bowls application. At the first stage, the effect of vibroacoustic massage single application over psycho-emotional characteristics was studied. 19 studied volunteers took part in our study. The testing results before and after exposures were compared according to the WAM (Weighted average mark), Zung, and Spielberg-Khanin tests. The study of the psycho-emotional sphere showed that after the vibroacoustic massage procedure, the indicators of "well-being" and "activity" of the WAM test significantly improved (p = 0.002). In addition, the depression level determined by the Zung test, personal anxiety indicators (p = 0.004), and situational anxiety ones (p = 0.028) decreased. At the second stage, 62 volunteers were divided into two groups. The first group underwent a vibroacoustic massage session according to the patented author's method. The second group received only acoustic exposure using only singing bowls. Differences in the Kerdo index were revealed in the dynamics, and in the first group, the changes were less significant than in the second one. Changes in heart rate variability characteristics for both groups were similar: there was an increase in parasympathetic influences at rest and during the orthostatic test (increased levels of RMSSD (Root Mean Square of Successive Differences), NN50, pNN50) and a decrease in sympathetic effects at rest and their slight increase with orthostatic loading (TINN, RR triangular index). The dynamics were more significant in the first group that received a vibroacoustic massage session. When assessing changes in the neurovegetative regulation levels activity of the heart rhythm, the main difference was associated with very low-frequency waves power dynamics during the orthostatic test. Thus, vibroacoustic massage using singing bowls improves the psycho-emotional state, reduces depression and anxiety, and increases Parasympaticus (autonomic nervous system) activity