α-RuCl is a major candidate for the realization of the Kitaev quantum spin liquid, but its zigzag antiferromagnetic order at low temperatures indicates deviations from the Kitaev model. We have quantified the spin Hamiltonian of α-RuCl by a resonant inelastic x-ray scattering study at the Ru L absorption edge. In the paramagnetic state, the quasi-elastic intensity of magnetic excitations has a broad maximum around the zone center without any local maxima at the zigzag magnetic Bragg wavevectors.
View Article and Find Full Text PDFBackground: No randomized trial of intracranial aneurysm coiling has compared long-term efficacy of polymer-modified coils to bare metal coils (BMCs). We report 5-year results comparing Matrix coils to BMCs. The primary objective was to compare the rates of target aneurysm recurrence (TAR) at 12 months.
View Article and Find Full Text PDFWe study the exchange interactions and resulting magnetic phases in the honeycomb cobaltates. For a broad range of trigonal crystal fields acting on Co^{2+} ions, the low-energy pseudospin-1/2 Hamiltonian is dominated by bond-dependent Ising couplings that constitute the Kitaev model. The non-Kitaev terms nearly vanish at small values of trigonal field Δ, resulting in spin liquid ground state.
View Article and Find Full Text PDFBackground and Purpose- The WEAVE trial (Wingspan Stent System Post Market Surveillance) is a postmarket surveillance trial mandated by the Food and Drug Administration to assess the periprocedural safety of the Wingspan Stent system in the treatment of symptomatic intracranial atherosclerotic disease. Methods- A total of 152 consecutive patients who met the Food and Drug Administration on-label usage criteria were enrolled at 24 hospitals and underwent angioplasty and stenting with the Wingspan stent. On-label criteria included age 22 to 80 years, symptomatic intracranial atherosclerotic stenosis of 70% to 99%, baseline modified Rankin Scale score ≤3, ≥2 strokes in the vascular territory of the stenotic lesion with at least 1 stroke while on medical therapy, and stenting of the lesion ≥8 days after the last stroke.
View Article and Find Full Text PDFMotivated by similarities between cuprate superconductors and two-leg ladder copper-oxide compounds and in order to obtain a better understanding of optical properties of cuprate superconductors we have studied the c-axis (along the ladder) optical conductivity [Formula: see text] of a doped [Formula: see text] two-leg ladder. Using exact diagonalization, we have calculated the conductivity and related quantities for cyclic ladders of up to 13 rungs. In agreement with results of an early study by Hayward and coworkers (Hayward et al 1996 Phys.
View Article and Find Full Text PDFWe present and analyze Raman spectra of the Mott insulator Ca_{2}RuO_{4}, whose quasi-two-dimensional antiferromagnetic order has been described as a condensate of low-lying spin-orbit excitons with angular momentum J_{eff}=1. In the A_{g} polarization geometry, the amplitude (Higgs) mode of the spin-orbit condensate is directly probed in the scalar channel, thus avoiding infrared-singular magnon contributions. In the B_{1g} geometry, we observe a single-magnon peak as well as two-magnon and two-Higgs excitations.
View Article and Find Full Text PDFJ Eur Acad Dermatol Venereol
June 2017
Background: Work-related skin diseases (WSD) are caused or worsened by a professional activity. Occupational skin diseases (OSD) need to fulfil additional legal criteria which differ from country to country. OSD range amongst the five most frequently notified occupational diseases (musculoskeletal diseases, neurologic diseases, lung diseases, diseases of the sensory organs, skin diseases) in Europe.
View Article and Find Full Text PDFAtoms undergoing strong-field ionization in two-color circularly polarized femtosecond laser fields exhibit unique two-dimensional photoelectron trajectories and can emit bright circularly polarized extreme ultraviolet and soft-x-ray beams. In this Letter, we present the first experimental observation of nonsequential double ionization in these tailored laser fields. Moreover, we can enhance or suppress nonsequential double ionization by changing the intensity ratio and helicity of the two driving laser fields to maximize or minimize high-energy electron-ion rescattering.
View Article and Find Full Text PDFThe double ionization of helium in bichromatic, circularly polarized intense laser fields is analyzed with a classical ensemble approach. It is found that counterrotating fields produce significant nonsequential double-ion yield and drive novel ionization dynamics. It is shown that distinct pathways to ionization can be modified by altering the relative intensities of the two colors, allowing for unique control of strong-field processes.
View Article and Find Full Text PDFWe study the effects of electron doping in Mott insulators containing d(4) ions such as Ru(4+), Os(4+), Rh(5+), and Ir(5+) with J=0 singlet ground state. Depending on the strength of the spin-orbit coupling, the undoped systems are either nonmagnetic or host an unusual, excitonic magnetism arising from a condensation of the excited J=1 triplet states of t(2g)(4). We find that the interaction between J excitons and doped carriers strongly supports ferromagnetism, converting both the nonmagnetic and antiferromagnetic phases of the parent insulator into a ferromagnetic metal, and further to a nonmagnetic metal.
View Article and Find Full Text PDFThe traditional arrangement for visualizing optical phenomena with the schlieren technique is modified to include a Mach-Zehnder geometry. This allows for the implementation of two independent knife edges along two different beam paths, resulting in an enhanced combined image that is uniquely adjustable. Post-processed combined images are also generated by spatially separating the paths from each arm and then colorizing and combining the images into a single composite.
View Article and Find Full Text PDFBackground And Purpose: The ability of polymer-modified coils to promote stable aneurysm occlusion after endovascular treatment is not well-documented. Angiographic aneurysm recurrence is widely used as a surrogate for treatment failure, but studies documenting the correlation of angiographic recurrence with clinical failure are limited. This trial compares the effectiveness of Matrix(2) polyglycolic/polylactic acid biopolymer-modified coils with bare metal coils and correlates the angiographic findings with clinical failure (ie, target aneurysm recurrence), a composite end point that includes any incident of posttreatment aneurysm rupture, retreatment, or unexplained death.
View Article and Find Full Text PDFWe propose a minimal model describing magnetic behavior of Fe-based superconductors. The key ingredient of the model is a dynamical mixing of quasidegenerate spin states of Fe(2+) ion by intersite electron hoppings, resulting in an effective local spin S(eff). The moments S(eff) tend to form singlet pairs and may condense into a spin nematic phase due to the emergent biquadratic exchange couplings.
View Article and Find Full Text PDFWe explore the phase diagram of spin-orbit Mott insulators on a honeycomb lattice, within the Kitaev-Heisenberg model extended to its full parameter space. Zigzag-type magnetic order is found to occupy a large part of the phase diagram of the model, and its physical origin is explained as due to interorbital t(2g)-e(g) hopping. The magnetic susceptibility, spin wave spectra, and zigzag order parameter are calculated and compared to the experimental data, obtaining thereby the spin coupling constants in Na(2)IrO(3) and Li(2)IrO(3).
View Article and Find Full Text PDFBackground: The dual model approach represents a promising solution for achieving semantically interoperable standardized electronic health record (EHR) exchange. Its acceptance, however, will depend on the effort required for integrating archetypes into legacy EHR systems.
Methods: We propose a corresponding approach that: (a) automatically generates entry forms in legacy EHR systems from archetypes; and (b) allows the immediate export of EHR documents that are recorded via the generated forms and stored in the EHR systems' internal format as standardized and archetype-compliant EHR extracts.
Objective: Deployment of a Neuroform microstent (NFM; Boston Scientific/Target, Freemont, California, USA) within acutely angled geometry may result in substantial deformations. This in vitro study was conducted to validate a novel alternative technique, consisting of intentional deployment of a NFM straight on into a terminus aneurysm, by assessing the mechanics, feasibility, and stability of the coils.
Methods: Silicon models of wide-neck terminus aneurysms were constructed.
We present a unique method for experimentally generating multiple vortices by way of a devil's vortex lens combined with a Fresnel lens using a spatial light modulator. These lenses have the multifocal properties of fractal zone plates combined with the orbital angular momentum of a spiral phase plate and can be tailored to fit within a small space on an optical bench. Results are presented alongside numerical simulations, demonstrating the robust nature of both the experimental method and the predictive power of the Huygens-Fresnel wavelet theory.
View Article and Find Full Text PDFWe report a case of atretic parietal cephalocele with a persistent parietal falcine sinus and partial absence of the straight sinus. The direct puncture angiographic study demonstrated that there was a major venous channel through the parietal skull defect. From the embryological point of view, this association may provide us with possible pathoetiologic evidence of congenital sinus pericranii is one of the alternative venous drainage pathways to compensate venous outflow in the cases of intracranial developmental anomalies.
View Article and Find Full Text PDFLiving as a commensal, Candida albicans must adapt and respond to environmental cues generated by the mammalian host and by microbes comprising the natural flora. These signals have opposing effects on C. albicans, with host cues promoting the yeast-to-hyphal transition and bacteria-derived quorum-sensing molecules inhibiting hyphal development.
View Article and Find Full Text PDFWe derive and study a spin one-half Hamiltonian on a honeycomb lattice describing the exchange interactions between Ir4+ ions in a family of layered iridates A2IrO3 (A=Li,Na). Depending on the microscopic parameters, the Hamiltonian interpolates between the Heisenberg and exactly solvable Kitaev models. Exact diagonalization and a complementary spin-wave analysis reveal the presence of an extended spin-liquid phase near the Kitaev limit and a conventional Néel state close to the Heisenberg limit.
View Article and Find Full Text PDFPurpose: To compare the clinical and angiographic outcomes of endovascular treatment of symptomatic intracranial stenosis between octogenarian and younger patients.
Methods: Data for 244 consecutive patients (173 men; mean age 61.6 years) who underwent angioplasty and/or stenting for intracranial atherosclerotic disease at 5 specialized centers were pooled.
Background: Antiplatelet agents are required to prevent thromboembolic complications from recently deployed intracranial stents, yet they carry a risk of bleeding complications that may be serious in patients with recent subarachnoid hemorrhage.
Method: Consecutive patients at a single institution who had ruptured intracranial saccular aneurysms treated with stent assisted coiling were retrospectively reviewed. Our primary outcomes were ischemic stroke related to the stent and bleeding complications possibly related to antithrombotic therapy.
Introduction: The study's purpose is to report the technical and clinical outcomes of a patient cohort that underwent vertebral artery ostium stent placement for atherosclerotic stenosis.
Methods: We retrospectively analyzed a prospectively collected database of neurointerventional procedures performed at a single center from 1999 to 2005. Outcome measures included recurrent transient neurological deficits (TNDs), stroke, and death.
Background: There are limited data on the relationship between patient and site characteristics and clinical outcomes after intracranial stenting.
Methods: We performed a multivariable analysis that correlated patient and site characteristics with the occurrence of the primary endpoint (any stroke or death within 30 days of stenting or stroke in the territory of the stented artery beyond 30 days) in 160 patients enrolled in this stenting registry. All patients presented with an ischemic stroke, TIA, or other cerebral ischemic event (e.