Eigenvalues of a potential dynamical system with damping forces that are described by an indefinite real symmetric matrix can behave as those of a Hamiltonian system when gain and loss are in a perfect balance. This happens when the indefinitely damped system obeys parity-time ( ) symmetry. How do pure imaginary eigenvalues of a stable -symmetric indefinitely damped system behave when variation...

We examine the PT-symmetry-breaking transition for a magnetic metamaterial of a finite extent, modeled as an array of coupled split-ring resonators in the equivalent circuit model approximation. Small-size arrays are solved completely in closed form, while for arrays larger than N=5 results were computed numerically for several gain and loss spatial distributions. In all cases, it is found that...

The quantum mechanical brachistochrone system with a PT-symmetric Hamiltonian is Naimark-dilated and reinterpreted as a subsystem of a Hermitian system in a higher-dimensional Hilbert space. This opens a way to a direct experimental implementation of the recently hypothesized PT-symmetric ultrafast brachistochrone regime of Bender et al. [Phys. Rev. Lett. 98, 040403 (2007)] in an entangled two-...

OBJECTIVE To assess the safety and efficacy of combined cataract extraction, posterior chamber intraocular lens placement, pars plana vitrectomy, fluocinolone acetonide intravitreal implant (Retisert), and Ahmed valves with pars plana tube (CPR-PT) in eyes with chronic, posterior, noninfectious uveitis. METHODS Retrospective study of patients who underwent CPR-PT. Outcome measures included vi...

The determination of Pt by ICP-MS in environmental and biological samples is well documented and generally performed after dissolution in dilute 3. On the other hand, I is poorly ionised in the plasma and, at low pH, memory effects and instability arise from the formation of potentially volatile species, such as I2 and HI, depending on the oxidation state of I. In order to investigate the role ...

A new fluorous PCP pincer ligand has been coordinated to Ni(II), Pd(II) and Pt(II). The air stable palladium complex, which promotes Heck reactions between methyl acrylate and either aryl bromides or iodides, can be recovered intact by fluorous solid-phase extraction and was reused four times in the Heck reaction between methyl acrylate and 4-bromoacetophenone without loss in catalytic activity.

BACKGROUND Osteoarthritis is a leading cause of disability. Nonsurgical treatment is a key first step. PURPOSE Systematic literature review of physical therapy (PT) interventions for community-dwelling adults with knee osteoarthritis. DATA SOURCES MEDLINE, the Cochrane Library, the Physiotherapy Evidence Database, Scirus, Allied and Complementary Medicine, and the Health and Psychosocial In...

This work explores chelating capabilities of 1-butyl-2-diphenylphosphino-3-methylimidazolium hexafluorophosphate (BDPPIMPF6) as a task-specific ionic liquid (TSIL) for metal extraction/preconcentration procedures. To this end, extraction by BDPPIMPF6 21 elements (Ag, Al, As, Au, Co, Cr, Cu, Fe, Ir, Mn, Ni, Pb, Pd, Pt, Re, Rh, Ru, Sc, Ti, V, and Zn) were evaluated. TSIL specifically forms comple...

INTRODUCTION Stroke frequently results in balance disorders, leading to lower levels of activity and a diminution in autonomy. Current physical therapies (PT) aiming to reduce postural imbalance have shown a large variety of effects with low levels of evidence. The objectives are to determine the efficiency of PT in recovering from postural imbalance in patients after a stroke and to assess whi...