Internal modulation of a random fiber laser.

A characterization of a modulated random mirror laser has been experimentally carried out. Unlike conventional internally modulated fiber lasers, no distortion of the modulating frequency or self-mode-locking effects were measured. The behavior of the laser using pulsed and analog modulation up to 12 GHz is shown.

Suspended-core fiber Sagnac combined dual-random mirror Raman fiber laser.

In the present work, a multiwavelength fiber laser based in the combination of a double-random mirror and a suspended-core Sagnac interferometer is presented. The double-random mirror acts by itself as a random laser, presenting a 30dB SNR, as result of multiple Rayleigh scattering events produced in the dispersion compensating fibers by the Raman amplification. The suspended-core fiber Sagnac interferometer provides the multi peak channeled spectrum, which can be tuned by changing the length of the fiber. The result of this combination is a stable multiwavelength peak laser with a minimum of ~25dB SNR, which is highly sensitive to polarization induced variations.

Evolución del desarrollo neurosensorial de los recién nacidos de muy bajo peso (≤ 1.500 g) en nuestro medio / Neurosensorial developmental follow-up of very low weight newborns (<1.500g) in our center

Objetivos: Estudiar la situación y evolución neurológica de los recién nacidos de muy bajo peso (≤ 1.500 gramos) en nuestro medio. Material y métodos: Estudio retrospectivo sobre la evolución neurológica de 268 recién nacidos de muy bajo peso (RNNB) durante un período de seguimiento de 5 años, a través de visitas periódicas a cargo de neonatólogos, neuropediatra y psicólogo y colaboración de otro servicios, realizándose exploraciones oftalmológicas, EEG y potenciales evocados. Período de estudio: 1993-1999. Se realizó estudio estadístico de un amplio número de variables con el programa SPSS para Windows. Las secuelas se clasificaron según la gravedad en leves, moderadas, graves, y en relación al tipo de deficiencia, en motoras, cognitivas, sensoriales, mixtas y plurideficiencias (cuando se asociaban una o más secuelas). Se analizaron también a frecuencia y mortalidad de los RN;BP a lo largo de los años de estudio y siguientes. Resultados: Resaltaba una media de peso baja para la edad gestacional (EG), edad materna superior a 30 años, elevado porcentaje de recién nacidos de bajos peso, cesáreas, patología obstétrica, complicaciones neurológicas y extraneurológicas, tratamientos médicos y ventilación mecánica (VM), porcentaje bajo de gestantes tratadas con corticoides y/o tocolíticos y de prematuros con surfactante. Reproducción asistida: 17,68%. Número de fetos > 1 el 37%. La tasa de mortalidad neonatal de los TNMBP ha ido disminuyendo en los últimos años, siendo de 17,50% en el 2005, 14,45% en el 2006 y 11,18% en el 2007. Asimismo, su incidencia ha ido incrementándose, siendo el 19% en el 2005, 18,2% en el 2006 y 21,8% en el 2007. Presentaron secuelas el 30% con tendencia ascendente, leves 46,5%, moderadas, 22,1% graves, 31,4%, predominando las motoras puras (43%), seguidas por las mixtas (27,9%), y plurideficiencias (17,4%). Hipoacusia neurosensorial, 4,8%. Retinopatía del prematuro (ROP), 17,2%. Parálisis cerebral (PC), 17,16%. El 40% tenían algún tipo de alteración en la ecografía transfontanelar (ECO), hemorragia intra/periventricular (HPIV), 22,7%, leucomalacia periventricular (LPV), 15,3%, trastornos del aprendizaje, 33% de los escolarizados. Tuvieron alta correlación estadística con la aparición de secuelas la enfermedad de la membrana hialina (EMH) displasia broncopulmonar (DBP), sepsis tardía, necesidad de oxígeno (O2) y ventilación mecánica (VM) y muy especialmente, la edad gestacional (EG) y alteraciones de la ecografía craneal. Conclusiones: Se observa incremento en la frecuencia y supervivencia de los RNMBP y una incidencia de secuelas similar a otras series con un alto porcentaje de graves. Las secuelas neurológicas se relacionan principalmente con la EG y la patología especialmente del sistema nervioso central (SNC), más la influencia de factores sobreañadidos (O2 y VM, entre otros).Las variables más predictivas fueron la ecografía craneal y la edad gestacional (AU)

Objective: To study the neurological evolution of very low birth weight newborns (VLBWN) (< 1.500 g) in our area. Patients and methods: Retrospective study of the neurological evolution of 268 VLBWN during a period of 5 years in a multidisciplinary approach with the participation of neonatology, pediatric neurology and psychology units. We have done periodical ophthalmologic explorations, electroencephalograms, and auditory evoked potentials. Period of the study: 1993-1999. The statistical study was done with SPSS and Windows. The damage were classified as mild, moderate and severe and according to the type of deficiency in motor, cognitive, sensorial, combined and plurideficiencies (when one or more lesions were present). The prevalence and mortality of VLBWN were also analyzed. Results: It is remarkable a mean weight low for gestational age, maternal age higher than 30 years of age, high percentage of low weight, cesarean sections, obstetric diseases, neurological and extraneurological complications, medical treatments and mechanical ventilation; low percentage of maternal treatment with corticoids and /or uterus relaxant medications and of premature newborns with suphactant. Assisted reproduction: 17,68%. Number of fetus > 1:37%. Te neonatal mortality rate of VLBWN has decreased along the years being 17,05% in 2005, 14,45% in 2006, and 11,18% in 2007. The incidence has increased being 18/1.000 in 2005, 18,3/1.000 in 2006, and 21/1.000 in 2007. Physcial damage was observed in 30%; mild in 46,5%, moderate in 22,1%, severe in 31,4%. The lesions were predominantly of motor type (43%), followed by combined in 27,9% and plurideficiencies in 17,4%. Neurosensorial deafness in 4,8%. Premature retinopathy in 17,2%. Neurosensorial deafness in 4,8%. Premature retinopathy in 17,2%. Cerebral palsy in 17,6%. 40% had some kind of alterations in the transfontanelle echography, 22,7% had intra/periventricular hemorrhage, 15.3% periventricular leukomalcia and 33% of the school age children had learning disabilities. The sequelae had high statistical correlation with membrane hyaline disease, bronchopulmonary dysplasia, late sepsis, oxygen dependency and mechanical ventilation, and specially with gestational age and transfontanelle echography alterations. Conclusions: We have observed an increment in the frequency and survival of the VLBWN. The incidence of damage is similar to other studies with a high percentage of severe deficiencies. The neurologic damage is mainly associated with gestational age and with central nervous system injuries; the influence of other factors such as oxygen and mechanical ventilation are also important. The most predictive variables are gestational age and transfontanelle echography (AU)

[Neurological newborn in our center and follow-up]. / El recién nacido neurológico en nuestro medio y su seguimiento.

INTRODUCTION: The progress made in perinatal health care in recent years has changed the epidemiology of neurological diseases during the neonatal period. The reduction in neonatal mortality has been accompanied by an increasingly large number of patients suffering from disabling diseases or with a risk of suffering from them; a prolonged follow-up and the joint efforts of neonatologists and neuropaediatricians are therefore essential. DEVELOPMENT: We review the welfare work and demand for health care for newborn infants with neurological disorders in our service, as well as perinatal neurological morbidity, the functioning of the follow-up outpatients department, and we also report some of the findings from our experience in following up high-risk newborn infants. CONCLUSIONS: The demand for neonatal health care is increasing, and it is important to take this into account so as to be able to plan better strategies for the use of health care resources and for caring for patients. In our population, preterm delivery and asphyxia are the chief perinatal factors leaving neurological sequelae, with an overall incidence that is similar to that reported in other research and a high proportion of severe sequelae. The follow-up programmes must be made cost-effective by better selection of the high risk population to be monitored and coordination with primary care paediatricians. Early detection of the deficits is essential to be able to implement early intervention, and this can be aided by a series of recommendations aimed at professionals and relatives, as well as by improved coordination between the different multidisciplinary groups involved in prevention and care programmes.

El recién nacido neurológico en nuestro medio y su seguimiento / Neurological newborn in our center and follow-up

Introducción. Los avances producidos en la asistencia perinatal han cambiado la epidemiología de las enfermedades neurológicas durante el período neonatal. Con la disminución de la mortalidad neonatal nos venimos enfrentando a un elevado y creciente número de pacientes afectos de enfermedades discapacitantes o con riesgo de padecerlas, y, por ello, es imprescindible un seguimiento prolongado y la labor conjunta de neonatólogos y neuropediatras. Desarrollo. Revisamos la labor asistencial y demanda de la asistencia del recién nacido neurológico en nuestro servicio, morbilidad neurológica perinatal,funcionamiento de la policlínica de seguimiento, y comunicamos algunos resultados de nuestra experiencia en el seguimiento de neonatos de riesgo. Conclusiones. La demanda de asistencia neurológica neonatal va aumentando, lo que es importanteconocer para una mejor planificación de los recursos sanitarios y la atención de los pacientes. En nuestro medio, la prematuridad y la asfixia son los principales factores perinatales de secuelas neurológicas, cuya incidencia global es similar a la de otros trabajos, con una alta proporción de secuelas graves. Los programas de seguimiento deben ser rentables, a través de una mejor selección de la población de riesgo que se debe controlar y de la coordinación con los pediatras de atención primaria. La detección precoz de las deficiencias es esencial para una intervención temprana, a lo que contribuye una serie de recomendaciones dirigidas a los profesionales y familias, así como una mejor coordinación de los diferentes grupos pluridisciplinarios en los programas de prevención y atención necesaria

Introduction. The progress made in perinatal health care in recent years has changed the epidemiology of neurological diseases during the neonatal period. The reduction in neonatal mortality has been accompanied by an increasingly large number of patients suffering from disabling diseases or with a risk of suffering from them; a prolonged follow-up and the jointefforts of neonatologists and neuropaediatricians are therefore essential. Development. We review the welfare work anddemand for health care for newborn infants with neurological disorders in our service, as well as perinatal neurological morbidity, the functioning of the follow-up outpatients department, and we also report some of the findings from our experience in following up high-risk newborn infants. Conclusions. The demand for neonatal health care is increasing, and it is important to take this into account so as to be able to plan better strategies for the use of health care resources and forcaring for patients. In our population, preterm delivery and asphyxia are the chief perinatal factors leaving neurological sequelae, with an overall incidence that is similar to that reported in other research and a high proportion of severe sequelae. The follow-up programmes must be made cost-effective by better selection of the high risk population to be monitored and coordination with primary care paediatricians. Early detection of the deficits is essential to be able to implement earlyintervention, and this can be aided by a series of recommendations aimed at professionals and relatives, as well as by improved coordination between the different multidisciplinary groups involved in prevention and care programmes