A Constant Torque Micro-Viscometer

We present a technique to measure the viscosity of microscopic volumes of liquid using rotating optical tweezers. The technique can be used when only microlitre (or less) sample volumes are available, for example biological or medical samples, or to make local measurements in complicated micro-structures such as cells. The rotation of the optical tweezers is achieved using the polarisation of the trapping light to rotate a trapped birefringent spherical crystal, called vaterite. Transfer of angular momentum from a circularly polarised beam to the particle causes the rotation. The transmitted light can then be analysed to determine the applied torque to the particle and its rotation rate. The applied torque is determined from the change in the circular polarisation of the beam caused by the vaterite and the rotation rate is used to find the viscous drag on the rotating spherical particle. The viscosity of the surrounding liquid can then be determined. Using this technique we measured the viscosity of liquids at room temperature, which agree well with tabulated values. We also study the local heating effects due to absorption of the trapping laser beam. We report heating of 50-70 K/W in the region of liquid surrounding the particle.

AS ESCALAS WECHSLER NO DIAGNÓSTICO NEUROPSICOLÓGICO DE CRIANÇAS COM DISTROFIA MUSCULAR DE DUCHENNE

Esta pesquisa teve por objetivo fazer uma avaliação neuropsicológica das funções cognitivas de crianças com Distrofia Muscular de Duchenne. Avaliou dez meninos, com idade entre seis e quinze anos. Utilizou-se da Escala de Inteligência Wechsler para crianças, WISC III, fazendo uma análise quantitativa e qualitativa dos dados. Os resultados quantitativos indicaram QIV muito diversificado entre os sujeitos, variando entre 53 e 97, sendo o QIVM = 77.4. A mesma variação foi observada no QIE, com resultados variando entre 57 e 88, com QIEM=71.2. O QITM foi de 71.4. . Esses resultados localizam-se na faixa limítrofe, dentro das variações normais da inteligência. A análise qualitativa fatorial segundo Figueiredo, registrou maior rebaixamento no fator III, Resistência à Distração, seguido do fator IV, Velocidade de Processamento. Na Escala Verbal, os subtestes que implicavam em utilização da Memória foram os mais comprometidos, comprovando pesquisas anteriores. Na Escala de Execução, o maior prejuízo observado foi devido à dificuldade em códigos e símbolos, sob pressão de tempo. Não foi observada nas crianças com resultados mais baixos, diferença significativa entre o QIV e o QIE. A transposição dos dados para a leitura neuropsicológica utilizou-se do diagrama de McFie. A grande diversidade dos resultados individuais recomenda estudos posteriores.

Upper and Lower Body Anaerobic Muscular Power is Adversely Affected by Active Dehydration

A gap exists in the knowledge of acute dehydration and its effect on anaerobic muscular power. Therefore the purpose of this study was to examine the effects of active dehydration by exercise in a hot humid environment on anaerobic muscular power.

The Acute Effects of Whole Body Vibration on Muscular Power and Agility

Context: While research suggests whole body vibration (WBV) positively affects measures of neuromuscular performance in athletes, researchers have yet to address appropriate and effective vibration protocols. Objective: To identify the acute effects of continuous and intermittent WBV on muscular power and agility in recreationally active females. Design: We used a randomized 3-period cross-over design to observe the effects of 3 vibration protocols on muscular power and agility. Setting: Sports Science and Medicine Research Laboratory at Florida International University. Patients or Other Participants: Eleven recreationally active female volunteers (age=24.4±5.7y; ht=166.0±10.3cm; mass=59.7±14.3kg). Interventions: Each session, subjects stood on the Galileo WBV platform (Orthometrix, White Plains, NY) and received one of three randomly assigned vibration protocols. Our independent variable was vibration length (continuous, intermittent, or no vibration). Main Outcome Measures: An investigator blinded to the vibration protocol measured muscular power and agility. We measured muscular power with heights of squat and countermovement jumps. We measured agility with the Illinois Agility Test. Results: Continuous WBV significantly increased SJ height from 97.9±7.6cm to 98.5±7.5cm (P=0.019, β=0.71, η2 =0.07) but not CMJ height [99.1±7.4cm pretest and 99.4±7.4cm posttest (P=0.167, β=0.27)] or agility [19.2±2.1s pretest and 19.0±2.1s posttest (P=0.232, β=0.21)]. Intermittent WBV significantly enhanced SJ height from 97.6±7.7cm to 98.5±7.7cm (P=0.017, β=0.71, η2 =0.11) and agility 19.4±2.2s to 19.0±2.1s (P=0.001, β=0.98, η2=0.16), but did not effect CMJ height [98.7±7.7cm pretest and 99.3±7.3cm posttest (P=0.058, β=0.49)]. Conclusion: Continuous WBV increased squat jump height, while intermittent vibration enhanced agility and squat jump height. Future research should continue investigating the effect of various vibration protocols on athletic performance.

Efeito do kinesio taping® no desempenho neuromuscular do quadríceps e no equilíbrio em sujeitos submetidos à reconstrução do ligamento cruzado anterior: ensaio clínico e randomizado

Objetivo: Investigar os efeitos imediatos do Kinesio Taping® no desempenho neuromuscular do Quadríceps Femoral (QF) de indivíduos submetidos à reconstrução do Ligamento Cruzado Anterior (LCA). Metodologia: trata-se de um ensaio clínico e randomizado composto por 45 indivíduos do sexo masculino que se encontravam entre 12ª e 17ª semanas após reconstrução do LCA. Todos foram submetidos a uma avaliação inicial composta pela análise do equilíbrio postural, através da baropodometria; determinação do Senso de Posição Articular (SPA), seguidas das avaliações isocinéticas excêntricas e concêntricas a 600/s, concomitante com a captação do sinal eletromiográfico do músculo Vasto Lateral (VL). Posteriormente foram alocados de forma aleatória em Grupo Controle (GC), Grupo Placebo (GP) e Grupo Experimental (GE). Os indivíduos do GE foram submetidos ao protocolo sugerido (aplicação do Kinesio Taping® no QF do membro acometido), enquanto os do GP utilizaram a aplicação do Kinesio Taping® sem as recomendações propostas pelo método. Já os indivíduos do GC permaneceram em repouso por dez minutos, sendo todos os indivíduos submetidos a uma reavaliação de forma idêntica à primeira. Foram analisadas as seguintes variáveis: pico de torque médio, pico de torque/peso corporal, potência muscular e erro absoluto do SPA para a dinamometria; amplitude ântero-posterior e médio-lateral para a baropodometria; e a amplitude de ativação muscular (Root Means Square - RMS) por meio da eletromiografia de superfície. Resultados: Nenhuma das variáveis analisadas apresentou diferenças intergrupo ou intragrupo. Conclusão: O Kinesio Taping® não altera o desempenho neuromuscular do quadríceps femoral de indivíduos submetidos à reconstrução do LCA para nenhuma das variáveis analisadas.

Efeito do ácido ascórbico sobre a espermatogênese de camundongos com distrofia muscular de Duchenne

The objective was to evaluate spermatogenesis alterations caused by DMD and the effect of the treatment using ascorbic acid in preventing those injuries. Twenty four mice were used, 12 from the C57BL/10 lineage (non-dystrophic) and 12 from the C57BL/10Mdx (dystrophic). The sample was divided in six groups containing 4 animals each, as: C30 = 30 days control; D30 = Dystrophic with 30 days; C60 = 60 days control; D60 = Distrophic with 60 days; CS60 = 60 days control supplemented with ascorbic acid and DS60 = Dystrophic with 60 days supplemented with ascorbic acid. The ascorbic acid supplementation was given in the water, 0,005 mg/day. After euthanasia, the testicles (right and left) were collected, weighted and cross sectioned. The material was fixed in the Karnovsky solution for 24 hours, included in resin for histological studies (morphological and morphometric analyzes) submitted to ultrastructural analysis and immunohistochemistry for caspase-3. There was a significant increase in the tunica propria percentage in D30 compared to C30 and D60. The ultrastructural analysis showed mitochondrial apoptosis evidence of Sertoli cells that can reduce sperm efficiency in CS60 and DS60. A higher volume density of apoptotic cells postivas to Caspase-3 in C30 and D30 versus DS60 compared to CS60. There was severe hypertrophy of the Leydig cells between D30 and D60. However, with supplementation was observed reversal of this change in DS60. The ultrastructure of Leydig cells to early presence of lipid vesicles was observed in the group pre-pubertal dystrophic (D30). Thus, the DMD affect the organization of the seminiferous tubules and intertubule, however, the ascorbic acid supplementation used for the treatment of DMD has been just enough to reduce the hypertrophy of the Leydig cells.