1,327 research outputs found

    Unidirectional Lasing Emerging from Frozen Light in Non-Reciprocal Cavities

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    We introduce a class of unidirectional lasing modes associated with the frozen mode regime of non-reciprocal slow-wave structures. Such asymmetric modes can only exist in cavities with broken time-reversal and space inversion symmetries. Their lasing frequency coincides with a spectral stationary inflection point of the underlying passive structure and is virtually independent of its size. These unidirectional lasers can be indispensable components of photonic integrated circuitry.Comment: 5 pages, 3 figure

    The preparation of zirconium powder

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    The preparation of zirconium powder by several different methods is fully described and evaluated. Most of the methods described are of a rather classical nature and these methods are discussed as taken from their original sources with suggestions for possible streamlining. Flow sheets are provided. The first series of steps to produce zirconium powder is almost invariably the production of pure zirconium tetrachloride or pure zirconium oxide from the tetrachloride. The processes described include the sodium reduction of zirconium tetrachloride, sodium reduction of the double alkali fluorides, the calcium reduction of zirconium oxide, hydrogen embrittlement and comminution of reduction products. The hydride method as utilized for zirconium sponge is a good process to make zirconium powder. This method which is described in detail can be nicely used to produce zirconium hydride or zirconium powder from any pure reduction product. While arc-melted or massive zirconium can be hydrided, material with larger surface area, e.g. sponge, is more favorable. The calcium reduction of zirconium oxide also has potential method to produce a good zirconium powder. It is concluded that suitable zirconium powder will be available as an increased demand arises. Methods tor safe handling of zirconium powder are briefly described --Abstract, page 2

    Twelve tips for teaching brief motivational interviewing to medical students

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    Background: Shifting from paternalistic to patient-centred doctor-patient relationships has seen a growing number of medical programs incorporate brief motivational interviewing training in their curriculum. Some medical educators, however, are unsure of precisely what, when, and how to incorporate such training. Aims: This article provides educators with 12 tips for teaching brief motivational interviewing to medical students, premised on evidence-based pedagogy. Methods: Tips were drawn from the literature and authors’ own experiences. Results: The 12 tips are: (1) Set clear learning objectives, (2) Select experienced educators, (3) Provide theoretical perspectives, (4) Share the evidence base, (5) Outline the “spirit”, principles, and sequence, (6) Show students what it looks like, (7) Give students a scaffold to follow, (8) Provide opportunities for skill practice, (9) Involve clinical students in teaching, (10) Use varied formative and summative assessments, (11) Integrate and maintain, and (12) Reflect and evaluate. Conclusions: We describe what to include and why, and outline when and how to teach the essential components of brief motivational interviewing knowledge and skills in a medical curriculum

    Ion-beam modification of fullerene

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    The response of thin films of fullerene (C60) to energetic ion impact is investigated. The diagnostics employed include Fourier-transform infrared and Raman spectroscopies, cross-sectional transmission electron microscopy, and atomic force microscopy. By combining the information obtained from these diagnostics with that from the dependence of the conductivity on ion dose, it is concluded that each C60 molecule completely disintegrates when hit by an energetic ion. The cross section for the destruction is about 6Ă—10-13 cm2 for irradiation with 620-keV Xe ions. The disintegration occurs when C atoms are knocked out of the molecule either directly by the impinging ion or by an energetic knock-on C atom within the damage cascade. This process is quite different from the Coulomb-explosion mechanism previously proposed in the literature. For very low ion doses

    Do Veterinarians recognize a Role for Physical Therapist in: Small Animal Physical Therapy and Rehabilitation?

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    The role of physical therapy and rehabilitation of an injured or aging small animal offers great potential. The increase in the use of domestic small animals, particularly canines, as companion animals, service animals and for athletic competition, advances in medical and surgical techniques in veterinary medicine and personal experiences participating in physical therapy appears to have created a desire from owners regarding the animal’s quality of life and quantity of years. There is little literature addressing small animal physical therapy rehabilitation and how such services might be accessed. We present an interview-based study to assess opinions of veterinarians to gauge whether they perceive a need for small animal physical therapy and rehabilitation. We further examine which health care professionals these veterinarians perceive are most qualified to render these rehabilitative services. Eight veterinarians from a rural, northeastern region of Georgia were interviewed. The results demonstrate that many veterinarians may not have received curriculum instruction in small animal physical therapy through veterinary school. Still, results reveal that veterinarians in this study support physical therapists playing a role in the rehabilitative treatment of small animals. This study further supports the need for interprofessional education and collaboration in the treatment of small animals and their physical therapy needs. &nbsp

    Heme Oxygenase-1 Expression Affects Murine Abdominal Aortic Aneurysm Progression.

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    Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme degradation, is a cytoprotective enzyme upregulated in the vasculature by increased flow and inflammatory stimuli. Human genetic data suggest that a diminished HO-1 expression may predispose one to abdominal aortic aneurysm (AAA) development. In addition, heme is known to strongly induce HO-1 expression. Utilizing the porcine pancreatic elastase (PPE) model of AAA induction in HO-1 heterozygous (HO-1+/-, HO-1 Het) mice, we found that a deficiency in HO-1 leads to augmented AAA development. Peritoneal macrophages from HO-1+/- mice showed increased gene expression of pro-inflammatory cytokines, including MCP-1, TNF-alpha, IL-1-beta, and IL-6, but decreased expression of anti-inflammatory cytokines IL-10 and TGF-beta. Furthermore, treatment with heme returned AAA progression in HO-1 Het mice to a wild-type profile. Using a second murine AAA model (Ang II-ApoE-/-), we showed that low doses of the HMG-CoA reductase inhibitor rosuvastatin can induce HO-1 expression in aortic tissue and suppress AAA progression in the absence of lipid lowering. Our results support those studies that suggest that pleiotropic statin effects might be beneficial in AAA, possibly through the upregulation of HO-1. Specific targeted therapies designed to induce HO-1 could become an adjunctive therapeutic strategy for the prevention of AAA disease

    Development of an equivalent force method and an application in simulating the radiated noise from an operating diesel engine

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    In this paper a new methodology is presented for applying measured accelerations and forces as excitation on a structural finite element model in order to perform a forced frequency response analysis. The computed vibration constitutes the excitation for an acoustic boundary element analysis. The new developments presented in this paper are associated with: the equivalent force method that can prescribe the acceleration at certain parts of the structure; the integration within a single process of test data that define the excitation, with the vibration analysis, and the acoustic prediction; the utilization of the new technology in simulating the noise radiated from a running engine and determining the effects of design changes. Numerical results for noise radiated from a running engine are compared to test data for a baseline design. The effect of two structural design modifications on the radiated noise is computed, and conclusions are deduced

    Identity in modal logic theorem proving

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    Fano Effect in a Few-Electron Quantum Dot

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    We have studied the Fano effect in a few-electron quantum dot side-coupled to a quantum wire. The conductance of the wire, which shows an ordinal staircase-like quantization without the dot, is modified through the interference (the Fano effect) and the charging effects. These effects are utilized to verify the exhaustion of electrons in the dot. The "addition energy spectrum" of the dot shows a shell structure, indicating that the electron confinement potential is fairly circular. A rapid sign inversion of the Fano parameter on the first conductance plateau with the change of the wire gate voltage has been observed, and explained by introducing a finite width of dot-wire coupling.Comment: 11 pages, 7 figure

    Personalized management of hypertensive patients: focus on prognostic biomarkers

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    Aim. To analyze level of circulating biomarkers of plasma vascular endothelial growth factor (VEGF) and tumor necrosis factor-α (TNF-α) during 3-month therapy with a fixed-dose combination of ramipril/indapamide (Konsilar-D24, AO Vertex, Russia), as well as to evaluate the antihypertensive efficacy of a fixed-dose combination of ramipril/indapamide (Konsilar-D24, JSC “Vertex”, Russia) in hypertensive (HTN) patients with type 2 diabetes (T2D).Material and methods. This prospective open-label study included 44 patients (aged 35 to 60 years) of both sexes with essential grade 1-2 HTN and concomitant compensated T2D, who did not reach the target blood pressure (BP) level using single or dual antihypertensive therapy, as well as patients who did not take antihypertensives. All patients included in the study initially underwent a set of standard clinical, laboratory and functional examinations in accordance with the clinical guidelines for the management of patients with HTN and T2D, as well as an assessment of the level of C-reactive protein, VEGF and TNF-α. Patients were monitored and treated with Konsilar-D24 for 3 months.Results. In 93,2% of patients, individual target BP values were achieved during the first 2-4 weeks of therapy with a fixed combination of ramipril/indapamide (Konsilar-D24). In the subsequent 3-month follow-up, the average daily BP level in all patients ranged from 129/79 mm Hg to 110/70 mm Hg. Three-month Konsilar-D24 therapy showed a decrease in microalbuminuria: the median values of microalbuminuria decreased by 2 times, and the decrease in the maximum recorded values reached 40% of the baseline. Decrease in mean TNF-α values after 3-month therapy with Konsilar-D24 was 33% of the baseline values, while the maximum recorded values during the specified period decreased by 17%. Decrease in median VEGF values after 3-month Konsilar-D24 therapy was 28%, while the maximum value decreased by 7%, the minimum — by 8%.Conclusion. Konsilar-D24 improves the prognosis in hypertensive patients not only by reducing BP to target values, but also by reducing the level of VEGF and TNF-α biomarkers that determine the progression of endothelial dysfunction, diabetic retinopathy, and microalbuminuria
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