Urban noise measurements in the City of Buenos Aires during the mandatory quarantine.

During preventive and mandatory social isolation decreed by the Argentine National Government to contain the spread of COVID-19, the city of Buenos Aires has experienced a marked decrease in vehicular traffic. To study this new scenario, the Acoustic Impact Department of the Environmental Protection Agency carried out a series of uninterrupted urban noise measurements for one week in five measurement points. The results were compared with those obtained before quarantine and with the maximum permissible limits according to current legislation. Although considerable decreases in sound energy have been obtained, it was not possible to determine global values of noise level reduction since the results were of different magnitudes in each location and period.

Determining the requirements, section quantity, and dimension of the virtual occlusal record.

STATEMENT OF PROBLEM: Conventional methods associated with many processes in dentistry are being replaced by methods that use digital technology. One of these processes is the making of occlusal records for the positioning of casts in a virtual articulator. Conventional interocclusal records and the articulator are currently being replaced by the intraoral virtual occlusal record and the virtual articulator. PURPOSE: The purpose of this study was to determine the requirements, quantity, and dimensions of the virtual occlusal record procedure in order to locate the mandibular cast's 3-dimensional (3D) spatial position in reference to its corresponding maxillary cast on a virtual articulator. MATERIAL AND METHODS: For the conventional procedure, 6 sets of casts were located in maximal intercuspal position without any interocclusal record. Then, using articulating paper, the occlusal contacts were determined. Afterward, the occlusal relationships and stone cast were digitized with a 3D scanner. To locate the maxillary cast, the occlusal contacts were compared by taking different sections as the virtual occlusal record. Finally, the optimum dimension of the virtual occlusal record was determined. RESULTS: This study determines the requirements, quantity, and dimensions of the virtual occlusal record using current reverse engineering tools. The combinations of the sections were first determined as follows: 3 sections (2 lateral and 1 frontal) and 2 lateral sections proved to be the most accurate. Then, the predictive values (PV) for dimension determination for the left-right lateral combination were calculated. CONCLUSIONS: The main conclusion of this study was that the combination of left and right lateral occlusal records was the most convenient. Additionally, the minimum optimum dimension for a virtual occlusal record was 12×15 mm.

Trastornos hematopoyéticos en trabajadores expuestos a radiaciones ionizantes / Hematopoietic disease in workers exposed to ionizing radiation

Los estándares de protección radiológica, se derivan de estimaciones principalmente de estudios epidemiológicos de los supervivientes japoneses de los bombardeos atómicos de Hiroshima y Nagasaki. El reciente accidente nuclear en Fukushima nos muestra que no estamos seguros y despierta el interés de conocer los efectos biológicos de las radiaciones ionizantes a dosis bajas por exposición laboral, mostrando la evidencia epidemiológica, relacionando las dosis y el tiempo de exposición, edad riesgo y tiempo de aparición de trastornos hematopoyéticos. La búsqueda bibliográfica se realizó mediante la selección de los términos MeSH y DeCS para buscar en las diferentes bases de datos. 82 estudios recuperados, más 14 estudios vía búsqueda manual, tras aplicarles los criterios de inclusión y exclusión se seleccionaron para revisión a texto completo 11 estudios: 4 cohorte y 7 casos y controles. En nuestra revisión hemos encontrado asociación para el desarrollo de Leucemia, P=0.03 con dosis <10 mSv de por vida, Mieloma Múltiple (MM) P=0.037, Leucemia Linfoide Crónica ERR: 4.09 Gy 95% CI:<0-14.41. Encontramos que existe asociación significativa entre exposición laboral a radiaciones ionizantes a bajas dosis y el desarrollo de Leucemia y Mieloma Múltiple. Se encontró evidencia de riesgo aumentado de padecer leucemia (excluyendo LLC) con tiempo de exposición mayor de 10 años y con dosis promedio de exposición <10 mSv. Existe evidencia en relación a la aparición de trastornos hematopoyéticos radioinducidos en el rango de 55-65 años coincidiendo con los últimos diez años de vida laboral. El hallazgo de una sugerente relación entre LLC y la exposición laboral a bajas dosis de radiaciones ionizantes deja la puerta abierta para futuras investigaciones

The actual Radiation protection standards are derived from estimates of epidemiological studies of Japanese survivors of the atomic bombings of Hiroshima and Nagasaki. The recent nuclear accident in Fukushima shows us that we are not safe at all and arouses the interest of knowing the biological effects of low dose of ionizing radiation in occupational exposure, showing the epidemiological evidence, relating the dose and duration of exposure, age and time of onset risk of hematopoietic disorders. The bibliographic research was conducted by selecting MeSH and DeCS terms to search different databases. 82 studies retrieved over 14 studies by manual search, according to the inclusion and exclusion criteria applied were selected for full text review 11 studies. 4 cohort and 7 case and controls. In our review we found association for the development of leukemia, P = 0.03 with doses <10 mSv lifetime, Multiple Myeloma (MM) P = 0.037, ERR Chronic Lymphocytic Leukemia 4.09 Gy 95% CI: <0-14.41. We found a significant association between occupational exposure to low-dose ionizing radiation and the development of leukemia and multiple myeloma. We found evidence of increased risk of leukemia (excluding CLL) with exposure time over 10 years and average exposure doses <10 mSv. There is evidence in relation to the appearance of hematopoietic disorders induced by radiation in the range of 55-65 years to coincide with the last ten years of work life. The finding of a suggestive relationship between LLC and occupational exposure to low doses of ionizing radiation leaves the door open for future research