321 research outputs found

    Switchable lasing in coupled multimode microcavities

    Get PDF
    We propose the new concept of a switchable multimode microlaser. As a generic, realistic model of a multimode microresonator a system of two coupled defects in a two-dimensional photonic crystal is considered. We demonstrate theoretically that lasing of the cavity into one selected resonator mode can be caused by injecting an appropriate optical pulse at the onset of laser action (injection seeding). Temporal mode-to-mode switching by re-seeding the cavity after a short cool-down period is demonstrated by direct numerical solution. A qualitative analytical explanation of the mode switching in terms of the laser bistability is presented.Comment: Accepted for publication in Physical Review Letters. Published, somewhat shortened versio

    A distributed control for a grasping function of a hyperredundant arm

    Get PDF
    The paper focuses on the control problem of a tentacle robot that performs the coil function of grasping. First, the dynamic model of a hyperredundant arm with continuum elements produced by flexible composite materials in conjunction with active-controllable electro-rheological fluids is analyzed. Secondly, both problems, i.e. the position control and the force control are approached. The difficulties determined by the complexity of the non-linear integraldifferential equations are avoided by using a basic energy relationship of this system. Energy-based control laws are introduced for the position control problem. A force control method is proposed, namely the DSMC method in which the evolution of the system on the switching line by the ER fluid viscosity is controlled. Numerical simulations are also presente

    Stability control of a hyperredundant arm for a grasping operation

    Get PDF
    In this paper a problem of a class of hyperredundant arms with continuum elements that perform the grasping function by coiling is discussed. This function is often met in the animal world as in the case of elephant trunk or octopus tentacle. First, the dynamic model in 3D-space is developed. The equations that describe the motion of the arm that carries a load by coiling are inferred. The stability of the motion is discussed. Numerical simulations of the motion towards an imposed target are presente

    A Randomized Parallel Controlled Study of the Efficacy and Safety of Lornoxicam Versus Etoricoxib after Total Knee Arthroplasty

    Get PDF
    Objectives: The aim of the study was to compare the postoperative analgesic efficacy and safety of lornoxicam versus etoricoxib for the first 48 hours after surgery. Methods: We conducted a prospective randomized controlled study on 110 patients ASAI-II scheduled for TKA under spinal anesthesia, who received either lornoxicam 8 mg PO at the end of surgery and a further 8 mg after 12 hours (Lornoxicam Group) or etoricoxib 120 mg at the end of surgery and one placebo pill after 12 hours (Etoricoxib Group). The primary outcome measure was the cumulative dose of morphine administered during the first postoperative 24 and 48 hours. Secondary outcomes were duration of analgesia and the side effects of the treatment. Results: The groups were similar in terms of demographic data. There are no significant differences between groups regarding the morphine consumption at 24 hours (36.2 ± 12 in Lornoxicam group and 34.5 ± 14.1 in Etoricoxib group) and 48 hours postoperatively (15.6 ± 12.8 in Lornoxicam group and 18 ± 12.3 in Etoricoxib group) or between the duration of analgesia (314.5 ± 70.4 in Lornoxicam group and 320.4 ± 89.2 in Etoricoxib group). Conclusion: Postoperative use of lornoxicam for 48 hours in the dose of 8 mg PO twice a day in patients undergoing TKA has an analgetic effect comparable to etoricoxib 120 mg, fewer patients experienced adverse symptoms in the etoricoxib group, but the difference was not statistically significant

    Stability control of a hyperredundant arm for a grasping operation

    Get PDF
    In this paper a problem of a class of hyperredundant arms with continuum elements that perform the grasping function by coiling is discussed. This function is often met in the animal world as in the case of elephant trunk or octopus tentacle. First, the dynamic model in 3D-space is developed. The equations that describe the motion of the arm that carries a load by coiling are inferred. The stability of the motion is discussed. Numerical simulations of the motion towards an imposed target are presente

    Primary vs. Secondary Antibody Deficiency: Clinical Features and Infection Outcomes of Immunoglobulin Replacement

    Get PDF
    <div><p>Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.</p></div

    Mechanochromic and thermochromic sensors based on graphene infused polymer opals

    Get PDF
    High quality opal‐like photonic crystals containing graphene are fabricated using evaporation‐driven self‐assembly of soft polymer colloids. A miniscule amount of pristine graphene within a colloidal crystal lattice results in the formation of colloidal crystals with a strong angle‐dependent structural color and a stop band that can be reversibly shifted across the visible spectrum. The crystals can be mechanically deformed or can reversibly change color as a function of their temperature, hence their sensitive mechanochromic and thermochromic response make them attractive candidates for a wide range of visual sensing applications. In particular, it is shown that the crystals are excellent candidates for visual strain sensors or integrated time‐temperature indicators which act over large temperature windows. Given the versatility of these crystals, this method represents a simple, inexpensive, and scalable approach to produce multifunctional graphene infused synthetic opals and opens up exciting applications for novel solution‐processable nanomaterial based photonics
    corecore