Circulation induced by diffused aeration in a shallow lake

Field surveys were carried out to investigate the surface jet flows and the resulting circulation patterns generated by diffused aeration in a shallow lake. In conrast to previous studies, the experimental conditions included point-source bubble plumes with very high air flow rates (100–400 L/min) relative to the shallow water depth (1.5 m). The results indicate that the surface jet velocity can be described by linear profiles. The decay of this velocity with distance displayed a similar behaviour to that reported in the literature, but the surface jet spread much faster under the present conditions. Combining our results with published data allowed for the generation of dimensionless correlations for the velocity and depth of the surface jet. A good agreement between the total circulation flow rates predicted by using the proposed correlations and integral modelling was also obtained. Lastly, a simple returning flow model was proposed to describe the circulation flow patterns induced by the bubble plumes. The results were also applied to assess the impact of circulation on vertical algae migration, which is important for water quality management.Keywords: aeration, algae migration, bubbles, jets, plume

FIJACIÓN TRANSPEDICULAR EN VÉRTEBRA C7 SIN GUÍA RADIOLÓGICA

Objetivo: Evaluar la eficacia de la fijación transpedicular con tornillos en la séptima vértebra cervical, sin guía radiológica. Material y métodos: Se realizó en cadáveres de la Universidad Andina Néstor Cáceres Velásquez, realizando una incisión quirúrgica, se localizó la vértebra C7, se determinó el punto de entrada del pedículo 3-4mm lateral y 5-6mm superior al centro de la masa lateral y se insertaron tornillos de 3,5 mm en ambos pedículos. Después se removió la vértebra C7 y se hizo estudio radiográfico para determinar si los tornillos estaban bien posicionados. Resultados: Se localizó adecuadamente el punto de entrada en 12 de los 18 pedículos (eficacia del 66,6%), encontrándose gran variabilidad lateralmente (2-5 mm) y cranealmente (3-10 mm). La angulación coronal fue correcta en 13 de 18 pedículos (72,3%). Los ángulos coronales fueron entre 38 y 62 grados. La angulación sagital fue correcta en 16 pedículos (88,8%). El diámetro transverso de los 18 pedículos fue entre 4 y 7 mm. Conclusiones: la eficacia promedio de este método es del 76%, debido a la gran variabilidad anatómica en la ubicación y dirección de los pedículos de la vértebra C7. Se recomienda uso lamino-foraminotomía para ver los pedículos durante la cirugía

Quantitative Distribution of DNA, RNA, Histone and Proteins Other than Histone in Mammalian Cells, Nuclei and a Chromosome at High Resolution Observed by Scanning Transmission Soft X-Ray Microscopy (STXM)

Soft X-ray microscopy was applied to study the quantitative distribution of DNA, RNA, histone, and proteins other than histone (represented by BSA) in mammalian cells, apoptotic nuclei, and a chromosome at spatial resolutions of 100 to 400 nm. The relative distribution of closely related molecules, such as DNA and RNA, was discriminated by the singular value decomposition (SVD) method using aXis2000 software. Quantities of nucleic acids and proteins were evaluated using characteristic absorption properties due to the 1s⁻π * transition of N=C in nucleic acids and amide in proteins, respectively, in the absorption spectra at the nitrogen K absorption edge. The results showed that DNA and histone were located in the nucleus. By contrast, RNA was clearly discriminated and found mainly in the cytoplasm. Interestingly, in a chromosome image, DNA and histone were found in the center, surrounded by RNA and proteins other than histone. The amount of DNA in the chromosome was estimated to be 0.73 pg, and the content of RNA, histone, and proteins other than histone, relative to DNA, was 0.48, 0.28, and 4.04, respectively. The method we present in this study could be a powerful approach for the quantitative molecular mapping of biological samples at high resolution