RESUMO
Nano-structures of biological systems can produce diverse spectroscopic effects through interactions with broadband light. Although structured coloration at the surface has been extensively studied, natural spectroscopic contrasts in deep tissues are poorly understood, which may carry valuable information for evaluating the anatomy and function of biological systems. Here we investigated the spectroscopic characteristics of an important geometry in deep tissues at the nanometer scale: packed nano-cylinders, in the near-infrared window, numerically predicted and experimentally proved that transversely oriented and regularly arranged nano-cylinders could selectively backscatter light of the long wavelengths. Notably, we found that the spectroscopic contrast of nanoscale fibrous structures was sensitive to the pressure load, possibly owing to the changes in the orientation, the degree of alignment, and the spacing. To explore the underlying physical basis, we further developed an analytical model based on the radial distribution function in terms of their radius, refractive index, and spatial distribution.
RESUMO
Brachial plexus shows several variations in its formation and branching pattern. Variations in the formation of the trunks are very rare. We studied 44 dissected specimens specifically for variations in the formation of the trunks of the brachial plexus. 5 cadavers (11.3 percent) showed variations in the formation of the trunks. All the variations were unilateral. In one cadaver (2.27 percent), the middle trunk was formed by union of C7 and C8 roots and lower trunk was formed by T1 root. Upper and middle trunks were fused with each other in one specimen (2.27 percent). In 3 specimen (6.81 percent), the C5 root pierced scalenus anterior before joining C6 to form the upper trunk. Knowledge of its variations is of importance to orthopedic surgeons, neurologists and anesthesiologists.
EL plexo braquial muestra algunas variaciones en su formación y patrón de ramificación. Las variaciones en la formación de los troncos son muy raras. Se disecaron 44 especímenes para observar las eventuales variaciones en la formación de los troncos del plexo braquial. Cinco cadáveres (11,3 por ciento) mostraron variaciones en la formación de los troncos. Todas las variaciones fueron unilaterales. En un cadáver (2,27 por ciento), el tronco medio se formó por la unión de las raíces C7 y C8 y, parte inferior del tronco, estaba formado por la raíz de T1. En un caso (2,27 por ciento) los troncos superior y medio se fusionaron entre sí. En 3 muestras (6,81 por ciento), la raíz de C5 cruzó el músculo escaleno anterior antes de unirse a C6 para formar la parte superior del tronco. El conocimiento de estas variaciones es importante para los cirujanos ortopédicos, los neurólogos y anestesiólogos.
