RESUMEN
An experimental method for quantitatively evaluating the elemental processes governing the indoor behaviour of naturally occurring radioactive aerosols was proposed. This method utilises transient response of aerosol concentrations to an artificial change in aerosol removal rate by turning on and off an air purifier. It was shown that the indoor-outdoor exchange rate and the indoor deposition rate could be estimated by a continuous measurement of outdoor and indoor aerosol number concentration measurements and by the method proposed in this study. Although the scatter of the estimated parameters is relatively large, both the methods gave consistent results. It was also found that the size distribution of radioactive aerosol particles and hence activity median aerodynamic diameter remained not largely affected by the operation of the air purifier, implying the predominance of the exchange and deposition processes over other processes causing change in the size distribution such as the size growth by coagulation and the size dependence of deposition.
Asunto(s)
Aerosoles/análisis , Aerosoles/química , Filtros de Aire , Contaminantes Radiactivos del Aire/análisis , Contaminantes Radiactivos del Aire/química , Contaminación del Aire Interior/análisis , Algoritmos , Simulación por Computador , Modelos Químicos , Tamaño de la Partícula , Sensibilidad y EspecificidadRESUMEN
The surface radioactivity concentrations of the radon progenies, (214)Pb and (214)Bi, were estimated from NaI(Tl) pulse height distributions during rain. The improvement in estimation errors caused by considering geometric structures around measuring points and infiltration of radionuclides was discussed. The surface radioactivity concentrations were determined by comparing the count rates at the full-energy peak ranges between observation and calculation with the electron-photon transport code EGS5. It was shown that the concentrations can be underestimated by about 30 % unless the obstacles around the detector or infiltration of radionuclides are considered in gamma ray transfer calculations at measuring points, where there are many tall obstacles, or the ground is covered with unpaved areas.
Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Hijas del Radón/análisis , Lluvia/química , Conteo por Cintilación/instrumentación , Conteo por Cintilación/métodos , Contaminantes Radiactivos del Agua/análisis , Algoritmos , Dosis de Radiación , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
In this study, the (222)Rn flux density distribution at surface was estimated in East Asia with the Bayesian synthesis inversion using measurement data and a long-range atmospheric (222)Rn transport model. Surface atmospheric (222)Rn concentrations measured at Hateruma Island in January 2008 were used. The estimated (222)Rn flux densities were generally higher than the prior ones. The area-weighted mean (222)Rn flux density for East Asia in January 2008 was estimated to be 44.0 mBq m(-2) s(-1). The use of the estimated (222)Rn flux density improved the discrepancy of the model-calculated concentrations with the measurements at Hateruma Island.
Asunto(s)
Movimientos del Aire , Contaminación Radiactiva del Aire/estadística & datos numéricos , Algoritmos , Atmósfera/química , Modelos Estadísticos , Radón/análisis , Teorema de Bayes , Simulación por Computador , Asia Oriental , Islas , Japón , Reconocimiento de Normas Patrones Automatizadas/métodos , Dosis de Radiación , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Experiments were carried out in a small enclosed booth for the purpose of understanding and modelling (218)Po behaviour. The experiment was conducted under two kinds of conditions without and with injection of incense smoke. A working model of (218)Po behaviour was applied to analyse the measured data. Under the condition without incense smoke, temporal changes in aerosol-attached and unattached (218)Po concentrations were successfully reproduced by the model. The deposition rate of unattached fraction and the rate of attachment were determined by the working model. Under the condition with incense smoke, temporal changes in (218)Po concentration were poorly simulated by the model. This can be attributed to the significantly increased aerosol concentration in small size ranges which is not properly considered in the attachment rate calculation in the model.
Asunto(s)
Aerosoles/análisis , Aerosoles/química , Contaminantes Radiactivos del Aire/análisis , Aire/análisis , Polonio/análisis , Radón/análisis , Movimientos del Aire , Contaminantes Radiactivos del Aire/química , Ambiente Controlado , Tamaño de la Partícula , Polonio/química , Monitoreo de Radiación/métodosRESUMEN
A method of estimating surface radioactivity concentrations of key anthropogenic radionuclides from NaI(Tl) pulse-height distribution observed at a monitoring station (MS) was discussed. In the estimation, a realistic assumption on geometric distribution of source and obstacles around the detector of the MS including the infiltration of radionuclides into the ground was used and the results were compared with ones with a commonly used assumption of a uniformly distributed plane source. The surface radioactivity concentration was determined by comparing the count rates at the full-energy peak ranges between observation and calculation with an electron-photon transport code EGS5. It was shown that the estimated absolute values of concentration differed by a factor of â¼1.5 depending on the assumption of infiltration depth. The estimated surface concentrations of (131)I, (134)Cs and (137)Cs were in good agreement with ones determined by the in situ measurements with an HPGe detector and the cumulative values of daily surface depositions.
Asunto(s)
Radioisótopos de Cesio/análisis , Rayos gamma , Yoduros/análisis , Fotones , Sodio/análisis , Espectrometría gamma/métodos , Talio/análisis , Humanos , Análisis de RegresiónRESUMEN
This study was performed to measure the activity size distribution of aerosol particles associated with short-lived radon decay products in indoor air at Nagoya University, Nagoya, Japan. The measurements were performed using a low pressure Andersen cascade impactor under variable meteorological conditions. The results showed that the greatest activity fraction was associated with aerosol particles in the accumulation size range (100-1000 nm) with a small fraction of nucleation mode (10-100 nm). Regarding the influence of the weather conditions, the decrease in the number of accumulation particles was observed clearly after rainfall without significant change in nucleation particles, which may be due to a washout process for the large particles.
Asunto(s)
Aerosoles , Contaminantes Radiactivos del Aire/análisis , Contaminación del Aire Interior , Hijas del Radón/análisis , Radón/análisis , Japón , Tamaño de la Partícula , Tiempo (Meteorología)RESUMEN
BACKGROUND: Several modifications to the original Fontan procedure have been proposed in order to decrease postoperative morbidity. Lateral tunnel and extracardiac total cavo-pulmonary connection are 2 such modifications. PATIENTS: Between August 2005 and December 2005, the extracardiac lateral tunnel procedure was performed in 5 patients. The age at operation ranged from 19 to 59 months (median 24 months) and the weight ranged from 9.2 to 16.1 kg (median 11.4 kg). RESULTS: There was no mortality. The mean operation time was 466 +/-118 minutes. The mean cardiopulmonary bypass time was 198 +/- 61 minutes. The mean durations of intubation, intensive care unit stay, drainage tube use, and hospital stay were 1 +/- 1, 7 +/- 3, 12 +/- 5 and 30 +/- 2 days, respectively. Postoperative catheterization findings demonstrated that the mean superior venous caval pressure, inferior venous caval pressure, ventricular volume and ventricular ejection fraction were 10.0 +/- 1.4 mmHg, 11.0 +/- 2.4 mmHg, 140 +/- 47% of normal and 58.0 +/- 6.8% , respectively. CONCLUSIONS: The short-term results of the extracardiac lateral tunnel compared favorably with the results of different types of Fontan operation. In addition this procedure has the potential for growth and anticoagulation therapy is unnecessary.
Asunto(s)
Procedimiento de Fontan/métodos , Anticoagulantes/administración & dosificación , Preescolar , Femenino , Humanos , Lactante , Masculino , Resultado del TratamientoRESUMEN
A 5-year-old boy was referred to our institute for cardiac evaluation having been previously seen at another center. He had been diagnosed a pulmonary atresia with intact ventricular septum just after birth, and undergone Blalock-Taussig shunts. Although his central pulmonary artery pressure was high (mean pressure 26 mmHg) after bilateral Blalock-Taussig shunts, multiple peripheral pulmonary artery stenosis protected his pulmonary vascular bed from pressure load. We released the multiple pulmonary artery stenosis partly by catheter intervention and partly by surgical operation, and staged Fontan operation was completed. The surgery in combination with catheter therapies would expand the indication of Fontan-type operation, and it would contribute to the patients' postoperative prognosis.
Asunto(s)
Angioplastia de Balón , Cateterismo Cardíaco , Cateterismo , Procedimiento de Fontan/métodos , Defectos del Tabique Interventricular/complicaciones , Defectos del Tabique Interventricular/terapia , Atresia Pulmonar/terapia , Enfermedad Veno-Oclusiva Pulmonar/terapia , Preescolar , Humanos , Masculino , Pronóstico , Atresia Pulmonar/complicaciones , Enfermedad Veno-Oclusiva Pulmonar/complicacionesRESUMEN
This paper describes a research-oriented modelling exercise that addresses the problem of assessing the movement of tritium from a contaminated perched aquifer to the land surface. Participants were provided with information on water table depth, soil characteristics, hourly meteorological and evapotranspiration data. They were asked to predict the upward migration of tritium through the unsaturated soil into the atmosphere. Eight different numerical models were used to calculate the movement of tritium. The modelling results agree within a factor of two, if very small time and space increments are used. The agreement is not so good when the near-surface soil becomes dry. The modelling of the alternate upward and downward transport of tritium close to the ground surface generally requires rather complex models and detailed input because tritium concentration varies sharply over short distances and is very sensitive to many interactive factors including rainfall amount, evapotranspiration rate, rooting depth and water table position.
Asunto(s)
Contaminantes Radiactivos del Suelo , Tritio/química , Contaminantes Radiactivos del Agua , Modelos TeóricosRESUMEN
The (222)Rn concentration profiles in soil have been measured at an anomaly spot in Tateishi, Japan. In winter, the concentrations were low and showed a negative gradient with depth, but in other seasons, the concentration had both positive and negative gradients with depth, and dramatically changed by time. On the assumption that there was ventilation in deep layers and with driving forces of wind and temperatures, these phenomena were successfully explained. This finding would contribute to a numerical model for (222)Rn transport in soil.
Asunto(s)
Modelos Químicos , Radioisótopos/química , Radón/química , Contaminantes Radiactivos del Suelo/análisis , Simulación por Computador , Humanos , Japón , Radioisótopos/análisis , Radón/análisis , Conteo por Cintilación , Estaciones del AñoRESUMEN
All stereoisomers of three diepoxyalkenes derived from (3Z,6Z,9Z)-trienes with a C21, C19, or C18 straight chain, lymantriid sex pheromones and their candidates, were synthesized by MCPBA oxidation of optically active epoxyalkadienes. Their chromatographic behaviors were examined with GC and LC equipped with achiral and chiral columns. Detailed inspection of the mass spectra of these epoxides indicated the following diagnostic ions for determining the chemical structures: m/z 128, 167, M-87 and M-85 for (Z)-cis-3,4-cis-6,7-diepoxy-9-enes; m/z 111, M-125 and M-69 for (Z)-cis-6,7-cis-9,10-diepoxy-3-enes; and m/z M-125 and M-139 for (Z)-cis-3,4-cis-9,10-diepoxy-6-enes. Mass chromatographic analysis that monitored these fragment ions revealed the existence of a new pheromonal compound with a C21 chain in an extract from virgin females of a lymantriid species, Perina nuda F. The three diepoxyalkenes were converted into the corresponding DMDS adducts, which showed characteristic ions from fragmentation between the two thiomethyl groups, reflecting the position of an original double bond.
Asunto(s)
Alquenos/síntesis química , Compuestos Epoxi/síntesis química , Mariposas Nocturnas/química , Atractivos Sexuales/química , Alquenos/química , Animales , Cromatografía de Gases , Cromatografía Liquida , Compuestos Epoxi/química , Hidrocarburos/química , Conformación MolecularRESUMEN
The resolution of insect pheromonal cis-monoepoxy racemates derived from (Z,Z)-6,9-dienes was examined employing chiral HPLC columns, and the results showed that a normal-phase column (Chiralpak AD) was suitable for both 6,7- and 9,10-epoxides with a C(17)-C(23) straight chain, as was a reversed-phase column (Chiralcel OJ-R) for the 6, 7-epoxides. To determine the absolute configuration of each separated enantiomer applying a modified Mosher's method, the epoxy ring was opened by methanolysis, and the (1)H-NMR data of (S)- and (R)-MTPA esters of the methoxyalcohols produced were analyzed. Further, the hydrogenated product of each enantiomer was chromatographed on the OJ-R column referring to the corresponding authentic chiral compounds with a saturated chain, which were prepared by a Sharpless epoxidation reaction. These analyses showed that the levorotatory 6,7- and 9,10-epoxides with shorter t(R)s possess 6S,7R and 9R,10S configuration, respectively, and the dextrorotatory enantiomers with longer t(R)s possess the opposite configuration. Utilizing this chiral HPLC, it was revealed that an abdominal tip extract of the fruit-piercing moth, Oraesia excavata Butler (Lepidoptera: Noctuidae), included (9S,10R)-(Z)-9, 10-epoxy-6-henicosene as a main sex pheromone component. The synthetic 9,10-epoxide with this configuration, which was separated from the racemate, exhibited stronger activity in electrophysiological and field tests against male moths than the enantiomer.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Compuestos Epoxi/análisis , Lepidópteros/química , Feromonas/análisis , Animales , Compuestos Epoxi/síntesis química , Compuestos Epoxi/química , Femenino , Lepidópteros/efectos de los fármacos , Masculino , Feromonas/química , Feromonas/farmacología , EstereoisomerismoRESUMEN
A one-dimensional numerical model for 222Rn transport in an atmospheric boundary layer was developed. The model consists of two parts: a prognostic hydrodynamic model including a turbulence closure model and an atmospheric diffusion model for 222Rn. The first part predicts meteorological conditions to provide the second part with vertical turbulence conditions which affects the vertical motion of 222Rn near the Earth's surface. Calculations with the model are compared with 222Rn concentrations measured during a variety of meteorological conditions, from clear days with high radiation and low winds to cloudy days of low radiation with high winds. The model's results represent well the typical diurnal variations of the 222Rn concentrations.
Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Radón/análisis , Conceptos Meteorológicos , Modelos BiológicosRESUMEN
This paper describes a new type of three-dimensional numerical model for 222Rn transport in an atmospheric boundary layer. The model is a combination of a prognostic hydrodynamic meteorological model including a turbulence closure model and an atmospheric diffusion model for 222Rn. The first part provides the second part with the meteorological conditions needed for calculations of the 222Rn transport and diffusion. The model is capable of giving consideration to horizontal source distribution, complex terrain, and non-uniform and non-steady atmosphere. The model's results were compared with 222Rn field measurements in a mountain-valley area and represented qualitatively a typical diurnal variation of the 222Rn concentration in nocturnal drainage flows. The model was also applied to the transport of 222Rn in a seacoast area. These results indicated that the model could be effective as a research tool for numerical analysis of 222Rn behavior under various atmospheric conditions.
Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Radón/análisis , Conceptos Meteorológicos , Modelos BiológicosRESUMEN
The purpose of this research was to obtain information on the speaking fundamental frequency (SFF) mean levels, variability and patterns of Japanese females and contrast them with those of Caucasian speakers of American English. To this end, 56 young women--32 Japanese and 24 Americans--read standard passages in either or both the Japanese and English languages. It was found that the Japanese exhibited higher fundamental frequencies than did the Americans for all speaking conditions, and this contrast was statistically significant. Additionally--and unlike the American speakers--most Japanese women exhibited bimodal SFF distribution patterns. It is judged that the observed differences in level and distribution result primarily from differences in the structure of the two languages.