RESUMEN
The interaction between nitrogen-doped graphene defects (N3V1 and N4V2 pyridinic, and N3V1 and N3V3 pyrrolic) and benzene have been investigated by applying density functional theory (DFT), together with the vdW-DF correction. We discovered that only the N3V3 pyrrolic defect is a reactive site (6π-component), forming a cycloadduct with benzene (4π-component) that has energy barriers below 154.38 kJ mol-1 (1.60 eV). The conduction and valence bands (HOMO and LUMO) for N3V3 form a degenerate pair of orbitals at the gamma point, with the same ionization potential (IP) and electron affinity (EA). Likewise, inspection of the orbital symmetries for both systems confirms that these must undergo concerted reactions based on the Woodward and Hoffmann principles of orbital symmetry, with the appropriate orbital occupancies. This is the first time that substitutionally doped graphene has been demonstrated to participate as a 6π-component for cycloaddition reactions with benzene.
RESUMEN
The ultrasonic diagnosis of salivary gland tumors can give a more accurate information than clinical data alone. For example, it will help differentiate intraglandular from extraglandular tumors and benign from malignant processes. We conducted a prospective study in 39 patients with parotidal or submaxillary tumors. Patients were evaluated with a physical exam and a with ultrasound. Results indicate that only 53.86% of the physical examinations were correct in their diagnosis compared to 87.18% of the those done by ultrasound. Specificity and sensibility for malignancy was 96.43% and 81.81% respectively. These results were similar to those reported by other authors. We conclude that the use of ultrasound techniques in the study of salivary gland pathology is well justified, due to its capacity to provide high resolution, improving clinical diagnosis.
Asunto(s)
Neoplasias de las Glándulas Salivales/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y Especificidad , UltrasonografíaRESUMEN
Se presenta un caso típico de sarcoidosis, desde el punto de vista clínico e histológico, con lesión de piel y ganglios (órganos en que la biopsia fue concluyente) en un hombre de la raza negra de 64 años de edad, cubano, quien además presentó hipergammaglobulinemia, así como incrementos de las fracciones IgG e IgM, en la electroforesis e inmunoelectroforesis respectivamente, además de encontrarse imágenes radiológicas compatibles con los defectos óseos seudoquísticos de Jungling(AU)
Asunto(s)
INFORME DE CASO , Humanos , Masculino , Persona de Mediana Edad , Sarcoidosis , Enfermedades de la PielRESUMEN
An immunoelectrophoretic study of serum from patients with non-treated recently acquired syphilis (RAS) is made for the first time in our country. Increases in IgM and IgG fractions were detected; the increase of the former exceeded to the latter in patients with cutaneous symptomatic recently acquired syphilis (CSRAS) in comparison with those having mucous cutaneous symptomatic recently acquired syphilis (MCSRAS). IgG were increased in 100% of patients with this latter disease, although both fractions were increased in patients with latent recently acquired syphilis (LRAS).