RESUMEN
We analyze the properties of strongly coupled excitons and photons in systems made of semiconducting two-dimensional transition-metal dichalcogenides embedded in optical cavities. Through a detailed microscopic analysis of the coupling, we unveil novel, highly tunable features of the spectrum that result in polariton splitting and a breaking of light-matter selection rules. The dynamics of the composite polaritons is influenced by the Berry phase arising both from their constituents and from the confinement-enhanced coupling. We find that light-matter coupling emerges as a mechanism that enhances the Berry phase of polaritons well beyond that of its elementary constituents, paving the way to achieve a polariton anomalous Hall effect.
RESUMEN
Semiclassical quantization rules and numerical calculations are applied to study polariton modes of materials whose permittivity tensor has principal values of opposite sign (so-called hyperbolic materials). The spectra of volume- and surface-confined polaritons are computed for spheroidal nanogranules of hexagonal boron nitride, a natural hyperbolic crystal. The field distribution created by polaritons excited by an external dipole source is predicted to exhibit raylike patterns due to classical periodic orbits. Near-field infrared imaging and Purcell-factor measurements are suggested to test these predictions.
RESUMEN
Fibromyalgia is a painful syndrome of non-articular origin, predominantly involving muscles, and the commonest cause of chronic widespread musculoskeletal pain. The diversity of therapeutic programs for patients with fibromyalgia reflects both the lack of a known pathophysiology for this disorder and the low efficacy of the current therapies. We studied the efficacy of tenoxicam and bromazepan in the treatment of patients with fibromyalgia. One hundred and sixty-four patients from our Rheumatology Outpatient Clinic fulfilling the American College of Rheumatology criteria for the classification of fibromyalgia, with widespread pain at study entry. Each of the 164 patients was randomly assigned to 1 of 4 treatment groups: double placebo (P), tenoxicam (20 mg) + placebo (T), bromazepan (3 mg) + placebo (B)m or tenoxicam (20 mg) + bromazepan 3 mg (TB). Patient global assessment of disease, pain, sleep quality, morning stiffness, and number of tender points were evaluated at baseline and 8 weeks afterwards. At the end of the trial, 17%, 10%, 12%, and 29% of the P, T, B, and TB patients, respectively, had clinical improvement. A statistically significant difference was found only between the T and TB groups. Our data indicate that treatment with tenoxicam + bromazepan can be effective for some patients with fibromyalgia, but the differences with the placebo group were neither clinically nor statistically significant.
Asunto(s)
Ansiolíticos/uso terapéutico , Antiinflamatorios no Esteroideos/uso terapéutico , Bromazepam/uso terapéutico , Fibromialgia/tratamiento farmacológico , Piroxicam/análogos & derivados , Adulto , Ansiolíticos/efectos adversos , Antiinflamatorios no Esteroideos/efectos adversos , Bromazepam/efectos adversos , Método Doble Ciego , Quimioterapia Combinada , Femenino , Humanos , Masculino , Piroxicam/efectos adversos , Piroxicam/uso terapéutico , Placebos , Estudios ProspectivosRESUMEN
BACKGROUND: Silent myocardial ischemia is a growing world health problem. It has been related to factors that promote an increase in myocardial oxygen demand or affect coronary vasomotor tone. Coronary artery disease has shown an increasing trend in Mexico in this century. HYPOTHESIS: The aim of the study was to estimate the strength of the association between some risk factors and the occurrence of silent myocardial ischemia. METHODS: A cross-sectional study was conducted and 249 individuals were screened by 24-h Holter electrocardiogram. Silent myocardial ischemia was diagnosed in patients with painless transient ST-segment depression. All subjects were interviewed for coronary risk factors and total serum cholesterol was measured. RESULTS: Silent ischemia was diagnosed in 115 patients (46%), who were older (59 +/- 9 vs. 57 +/- 11 years; p = 0.01). In a logistic regression analysis, a lower risk for silent ischemia was found in patients with thrombolysis [odds ratio (OR) 0.28; 95% confidence interval (CI 95%) 0.14-0.53], or those who followed their medical treatment (OR 0.16; CI 95% 0.04-0.68). The major risk factors were hypercholesterolemia (OR 1.6; CI 95% 0.9-2.9) and more severe coronary artery disease (OR 2.5; CI 95% 1.1-5.7). CONCLUSIONS: Some coronary risk factors are related to silent ischemia. It is still important to diagnose this entity, but modification of its related risk factors should be kept in mind to diminish its occurrence and its severe consequences.
Asunto(s)
Isquemia Miocárdica/epidemiología , Colesterol/sangre , Angiografía Coronaria , Estudios Transversales , Electrocardiografía Ambulatoria , Femenino , Humanos , Incidencia , Masculino , México/epidemiología , Persona de Mediana Edad , Isquemia Miocárdica/sangre , Isquemia Miocárdica/diagnóstico , Oportunidad Relativa , Factores de Riesgo , Encuestas y CuestionariosRESUMEN
By merging bottom-up and top-down strategies we tailor graphene's electronic properties within nanometer accuracy, which opens up the possibility to design optical and plasmonic circuitries at will. In a first step, graphene electronic properties are macroscopically modified exploiting the periodic potential generated by the self assembly of metal cluster superlattices on a graphene/Ir(111) surface. We then demonstrate that individual metal clusters can be selectively removed by a STM tip with perfect reproducibility and that the structures so created are stable even at room temperature. This enables one to nanopattern circuits down to the 2.5 nm only limited by the periodicity of the Moiré-pattern, i.e., by the distance between neighbouring clusters, and different electronic and optical properties should prevail in the covered and uncovered regions. The method can be carried out on micro-meter-sized regions with clusters of different materials permitting to tune the strength of the periodic potential.