Few layers graphene as thermally activated optical modulator in the visible-near IR spectral range.

We report the temperature modulation of the optical transmittance of a few layers of graphene (FLG). The FLG was heated either by the Joule effect of the current flowing between coplanar electrodes or by the absorption of a continuous-wave 532 nm laser. The optical signals used to evaluate the modulation of the FLG were at 633, 975, and 1550 nm; the last wavelengths are commonly used in optical communications. We also evaluated the effect of the substrate on the modulation effect by comparing the performance of a freely suspended FLG sample with one mounted on a glass substrate. Our results show that the modulation of the optical transmittance of FLG can be from millihertz to kilohertz.

[Cryptococcosis of the central nervous system. A report of five cases]. / Criptococosis del sistema nervioso central. A propósito de cinco casos.

INTRODUCTION: Since the 1980s, in relation to the spread of AIDS, there has been an enormous increase in cryptococcosis, a mycotic disorder which usually affects the central nervous system (CNS). This disease is caused by Cryptococcus neoformans, a microorganism acquired by inhalation of bird excrement. This germ produces a capsule which protects it from phagocytosis, can synthesize melanin which acts as an antioxidant of the cytotoxic lymphocytes and can reproduce at body temperature. Clinically it may show as chronic or subacute meningitis and/or encephalitis, as endocranial hypertension or as an intracranial space occupying lesion (crytococcoma). To establish the diagnosis, Chinese ink, culture and the latex agglutination test are useful. Treatment is with amphotericin B associated or not with fluocytokine and fluconazole, the protocol used depending on the clinical form. OBJECTIVE: To review the most up-to-date literature on cryptococcosis of the CNS to study the condition in relation to five cases. CLINICAL CASES: We report five patients with cryptococcosis of the CNS diagnosed and treated in the Instituto Nacional de Neurología y Neurocirugia de la Habana, Cuba, showing an increase in the frequency of the occurrence of cases not related to HIV infection, great variety of clinico-humoral presentation and the characteristics of the treatment given. CONCLUSION: Cryptococcosis can be cured completely when the condition is diagnosed early; without treatment it is invariably fatal.

Electrodo capacitivo de alta sensibilidad para la detección de biopotenciales eléctricos / Capacitive Electrode with High Sensitivity for Detection of Electrical Biopotentials

En este trabajo se presenta el diseño e implementación de un electrodo capacitivo de no contacto para la detección de biopotenciales en el cuerpo humano. Se presentan los circuitos eléctricos, el criterio de selección del amplificador operacional en base al análisis de la resistencia óptima de ruido, se describe el montaje físico, se presentan las señales obtenidas con este y la evaluación de su desempeño en base a la relación señal a ruido S/N. Se muestra el desempeño de diversos amplificadores operacionales y se demuestra la versatilidad del electrodo para detectar diversos biopotenciales realizando ajustes en los valores de dos componentes eléctricos del electrodo.

In this work the design and implementation of a capacitive non-contact electrode for detecting biopotentials in the human body is presented. Electrical circuits, the selection criteria of the operational amplifier based on the analysis of the optimal noise resistance are presented, the physical assembly is described and the signals obtained and evaluation of its performance are presented based on the signal-to-noise ratio S/N. We show the performance of several operational amplifiers and it is shown the versatility of the electrode to detect several biopotentials making adjustments to the values of two electrical components of the electrode.

[Prevalence of Parkinson disease in an urban area of the Ciudad de La Habana province, Cuba. Door-to-door population study]. / Prevalencia de la enfermedad de Parkinson en un área urbana de la provincia Ciudad de La Habana, Cuba. Estudio poblacional "puerta a puerta".

OBJECTIVE: To determine the prevalence of Parkinson's disease in an urban area of Havana City province, Cuba. BACKGROUND: Parkinson's disease is one of the most frequent chronic neurodegenerative diseases in the elderly. Prevalence varies widely between different geographic areas and type of studies. To the author's knowledge, there are not epidemiological data on Parkinson's disease in Cuban population that allows a real estimation of the true magnitude of the disease. PATIENTS AND METHODS: A "door-to-door" population study was carried out between November and December 1997. The area total population aged 15 years and over (n = 17.784) was interviewed and examined during the first phase of the study. This phase was performed by the 33 family doctors practicing in that area. An experienced neurologist previously trained the family doctors on making Parkinson's disease diagnosis. Diagnosis was based on the Brain Bank Society criteria. In order to make a definitive diagnosis of Parkinson's disease every subject that received such a diagnosis during the first phase was re-evaluated by two experienced neurologists. Those subjects with final diagnosis of Parkinson's disease were asked about family history of the disease. Prevalence rates were calculated according to sex, age group, color of the skin and smoking status. RESULTS: A total of 24 subjects received the final diagnosis of Parkinson's disease, yielding a population prevalence rate of 135 x 100,000 inhabitants. Eight subjects (33.3%) received a diagnosis of Parkinson's disease for the first time (de novo cases). Subjects with white color of the skin and non-smoking subjects showed a statistically significant higher prevalence of Parkinson's disease than subjects with non-white color of the skin and non-smokers respectively. Only 3 (12.5%) subjects reported a family history of Parkinson's disease. CONCLUSION: The population of this area has a low prevalence rate of Parkinson's disease compared to that reported in other populations. The observed low frequency of family history of the disease suggests that the main determinants of Parkinson's disease are environmental factors yet to be identified.

The mother-child interaction and clinical judgment during acute pediatric illnesses.

OBJECTIVES: For acutely ill children living in less than optimal environments, mothers and pediatricians may have a heightened perception of illness severity, a lower specificity of clinical judgments, and a tendency to over-utilize resources. We examined the mother-child interaction in order to understand the relation of less optimal environments to clinical judgment and resource use. STUDY DESIGN: At the 2-week and 6-, 15-, and 24-month well child visits of 316 children, the mother-well child interaction was assessed by using the Biringen's Emotional Availability Scales (EAS). Data were gathered regarding maternal depression and sense of competence, infant temperament, maternal social support, life events, the home environment, and demographics. At ill visits, the mother-ill child interaction was assessed by using the EAS, and mothers and pediatricians independently assessed illness severity using the Acute Illness Observation Scales. Resource use during the illness was evaluated. RESULTS: One thousand nine hundred eight-three acute illnesses were assessed. A less optimal mother-child interaction was significantly (P <.05 for all comparisons) associated with poorer reliability of mothers' judgments, lower specificity of mothers' judgments (71% vs 85%) and pediatricians' judgments (92% vs 97%), and greater use of resources (eg, for hospitalizations, 2.6% of visits vs 0.7%). Adverse maternal, infant, and demographic characteristics were associated with a less optimal mother-well child (r = 0.68) and mother-ill child (r = 0.80) interaction, a heightened perception of illness severity, and greater resource use. CONCLUSION: Less optimal environments adversely affect the mother-child interaction; a poor mother-child interaction is correlated with low specificity of clinical judgment and over-utilization of resources.

Nifedipino: Cuantificación en tabletas / Nifedipine: Cuantification in pills

El nifedipino es un medicamento empleado con éxito en el control de la hipertensión arterial que se produce en cantidades apreciables en los Laboratorios MedSol. Como parte de los esfuerzos que se realizan para disminuir los costos de calidad de los fármacos, el presente trabajo desarrolla un procedimiento analítico que emplea como solvente de extracción el etano de producción nacional, basándose en a propiedad de este producto de presentar un máximo de absorción alrededos de 342 nm con sensibilidad apropiada.Se sustitituye de esta manera el dioxido, reactivo de importancia y toxicidad comprobada para el organismo humano. La técnica ha sido introducida en la práctica durante 18 meses con resultados satisfactorios en cuanto a eficiencia. Se ha cumplido así con los procedimientos establecidos al efecto en los Laboratorios MedSol que se apoya en lo relacionado con este aspecto de la USP 23