RESUMEN
Resumen: La señal de la amplitud en análisis de Potenciales Evocados Visuales (PEVs) es una variable que depende del tipo y posición de los electrodos, de la fuente, del estímulo y por consecuente, de la intensidad luminosa por lo que es fundamental reportarla para cada diseño experimental y así, garantizar su reproducibilidad. El objetivo de este trabajo es caracterizar una lámpara con 96 LEDs para la adquisición de PEVs en ratas. Se midió la iluminancia y la intensidad luminosa promedio en un sistema espacial XYZ de 8 cm3 aplicable a un sistema estereotáxico para la fijación de ratas. Se realizaron desplazamientos cada 2 cm en cada plano. Se observó que debido a la distribución geométrica de los LEDs la distribución de la iluminancia no sigue la ley del inverso cuadrado, ya que aumenta conforme la lámpara se aleja. Finalmente, se seleccionó una coordenada para la colocación del ojo de la rata empleando una intensidad luminosa promedio para la adquisición del PEV de 1.043 cd e iluminancia de 128.77 luxes a una distancia ojo-lámpara de 9 cm. Una vez caracterizada la intensidad luminosa y de acuerdo con los PEVs obtenidos, esta lámpara puede utilizarse para estudios PEV en ratas en investigaciones posteriores.
Abstract: Signal amplitude for recordings of Visual Evoked Potentials (VEPs) is a variable dependent on the type and position of the electrodes, the source, the stimulus and consequently the luminous intensity; therefore, it is relevant to report it to assure experimental reproducibility. The objective of this work is to characterize flash lamp with 96 LEDs in order to perform the acquisition of VEPs in rats. We measure the illuminance and mean light intensity on space system XYZ of 8 cm3 corresponding to a stereotaxic frame for rodents. Displacements were performed every 2 cm in each plane. Because of the geometric distribution of the LEDs in the EBNeuro lamp the spatial distribution of illuminance does not follow the law of the inverse square, because the illuminance increases as the lamp goes away. Finally a spatial coordinate was selected for the rat eye positioning were the mean luminous intensity was 1.043 cd and 128.77 luxes of illuminance at an eye-lamp distance of 9 cm. According to the obtained VEPs and spatial characterization this lamp can be used for acquire of recordings PEV in rats for further investigations.
RESUMEN
Purpose: This study was designed to investigate the present conditions of illumination techniques in dental clinics in order to contribute improvement of operating environment. This study also aimed exploring qualitative and quantitative luminous intensity required for color temperature in dental clinic illumination, which was a critical part of esthetic dentistry. Materials and methods: A total of forty-eight local dental clinics were selected for sampling a) luminous intensity, and b) color temperature. The author measured the luminous intensity and the color temperature with lux meter and color meter respectively between 12pm and 2pm. The dental unit chair placed in the general operation positions were kept the distance 60 cm, then all dental units were measured three times and averaged. The author measured the luminous intensity and color temperature with both common dental operating light and then without operating light in different office environments. The study was conducted under three conditions: 1. artificial illumination in clear day light 2. artificial illumination in cloudy day light, and 3. artificial illumination alone. Results: The results obtained were as follows. 1. The average luminous intensity in dental clinic lighting was 425 lux which was not sufficient to produce the optimal shade of the patient's teeth. Furthermore, the average luminous intensity even in full operating lighting was 9532 lux which fell short of the required level of 10,000 lux. 2. The average color temperature of all dental clinics surveyed was 5169 K which met the optimal range. However, only 33.3% fell in the correct region between 5,000-5,500 K as 25% were over 5,500 K and 41.6% were below 5,000 K. As a result, 66.7% were under insufficient color temperature conditions. 3. The dental unit chair placed next to a window, hence exposure to natural lighting, had significantly higher luminous intensity and color temperature compared to the dental unit chair which didn't have a window or natural lighting. 4. The data analysis revealed that only 6.3% of the dental clinic were met the standard of the average luminous intensity and color temperature.