Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
1.
Phys Rev Lett ; 121(13): 137402, 2018 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-30312058

RESUMO

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.

2.
Nano Lett ; 15(7): 4455-60, 2015 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-26083960

RESUMO

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.

3.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-633661

RESUMO

INTRODUCTION: Tuberculosis (TB) is a chronic infectious disease, with a growing incidence seen worldwide. Among the tuberculous infections, pulmonary TB remains to be the most common, with extrapulmonary TB seen in only less than 2.0% of this population. Although the latter remains to be rare, it is commonly found in the lymph nodes, gastrointestinal (GI) and genitourinary (GU) tracts, weight- bearing joints, and the meninges. But, however rare extra- pulmonary tuberculosis may be, some patients have reported the occurrence of such in less common sites.In patients with autoimmune diseases, the diagnosis and management of microbial infections remain complicated because of their immunocompromised nature, and because of the medications they receive. As tuberculosis is a curable disease, early identification and proper treatment should be applied to avoid further patient compromise.OBJECTIVE: The objective of this paper is to present three cases of patients diagnosed with extrapulmonary tuberculosis at atypical sites namely tuberculous cellulitis, endometrial tuberculosis, and tuberculous dactylitis, accompanying a primary rheumatologic disease.CASES: Case 1 is a patient with Dermatomyositis who presented with pain and non- traumatic ecchymosis on his right gluteus, later diagnosed as TB cellulitis through a positive AFB smear of the aspirate. Case 2 is a patient with SLE whose amenorrhea was initially attributed to Cyclophosphamide. However, further work up revealed tuberculous bacteria through AFB smear of the curetting, hence was diagnosed with Endometrial TB. Case 3 reports another patient with SLE, who was diagnosed with recurrent TB dactylitis through a positive AFB smear of the biopsy.CONCLUSION: Despite the high endemicity of the Philippines for tuberculosis, extra- pulmonary TB continues to be underrecognized. Patients with autoimmune conditions are most likely to suffer from such infections due to their immunocompromised state. High suspicion and management remain to be the cornerstone to avoid diagnostic delays, and improve outcome.


Assuntos
Humanos , Masculino , Feminino , Adulto , Dermatomiosite , Celulite (Flegmão) , Equimose , Amenorreia , Suporte de Carga , Tuberculose Pulmonar , Meninges , Doenças do Colágeno , Doenças Autoimunes , Linfonodos , Bactérias , Artrite Reumatoide
4.
Sci Rep ; 4: 7314, 2014 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-25472802

RESUMO

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.

5.
MAPFRE med ; 12(3): 204-213, jul. 2001. tab
Artigo em Es | IBECS | ID: ibc-8753

RESUMO

Uno de los más serios y persistentes problemas en salud pública es la lumbalgia de origen ocupacional, que constituye un problema sanitario y socioeconómico de primer orden en los diversos colectivos de la población trabajadora. El estudio tiene como objetivo conocer la prevalencia debida a patalogía lumbar en los trabajadores de una empresa química, además de identificar algunos de los factores de riesgo de índole laboral que con mayor frecuencia se presentan en esta patalogía. Se realizó un estudio transversal, considerándose como población objeto de estudio a los trabajadores presentes en esa empresa de Huelva durante el año 1996. Para la cumplimentación de los datos del estudio se utilizó un cuestionario validado previamente. Las variables del estudio fueron definidas con antelación, una vez establecidos los criterios diagnósticos del problema que se iba a estudiar y fueron posteriormente incluidas en los apartados del cuestionario y determinadas en los registros que se analizaron. Entre los resultados hemos de destacar los siguientes: alta prevalencia de patalogía lumbar (35 por ciento), elevada recurrencia (80 por ciento), necesidad de baja laboral (20 por ciento) y alta frecuencia de antecedentes lumbares (39 por ciento). Se identificaron como factores agravantes de patalogía lumbar con significación estadística: posición de trabajo de rodillas, manejo de cargas pesadas, levantamiento y empuje de cargas y frecuencia de levantamientos (de 26 a 50 vecesldía); asimismo, la antigüedad en la empresa y el lugar de trabajo están correlacionados con el deseo de cambio de puesto. Como factores agravantes pero sin significación estadística se detectaron: posición en cuclillas, inclinado, posturas forzadas, manejo de cargas ligeras, vibraciones y sedentarismo (entendido como la no práctica de actividades extralaborales) (AU)


Assuntos
Adulto , Feminino , Masculino , Pessoa de Meia-Idade , Humanos , Dor Lombar/epidemiologia , Doenças Profissionais/epidemiologia , Indústria Química/estatística & dados numéricos , Estudos Transversais , Fatores de Risco , Prevalência , Carga de Trabalho/estatística & dados numéricos , 16360
6.
Clin Cardiol ; 23(4): 248-52, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10763071

RESUMO

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.


Assuntos
Isquemia Miocárdica/epidemiologia , Colesterol/sangue , Angiografia Coronária , Estudos Transversais , Eletrocardiografia Ambulatorial , Feminino , Humanos , Incidência , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Isquemia Miocárdica/sangue , Isquemia Miocárdica/diagnóstico , Razão de Chances , Fatores de Risco , Inquéritos e Questionários
7.
Pain ; 65(2-3): 221-5, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8826510

RESUMO

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.


Assuntos
Ansiolíticos/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Bromazepam/uso terapêutico , Fibromialgia/tratamento farmacológico , Piroxicam/análogos & derivados , Adulto , Ansiolíticos/efeitos adversos , Anti-Inflamatórios não Esteroides/efeitos adversos , Bromazepam/efeitos adversos , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Masculino , Piroxicam/efeitos adversos , Piroxicam/uso terapêutico , Placebos , Estudos Prospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...