RESUMO
Arterial stiffening is associated with a number of known cardiovascular risk factors, including advancing age, increased systolic blood pressure (SBP), diabetes, hypertension, heart failure, myocardial infarction, and obesity. Many methodologies, both invasive and noninvasive, have been applied to the assessment of the stiffening of large elastic arteries in vivo, but there is no economically and/or universally accepted means of screening patients for atherosclerosis. From preliminary studies, a novel parameter, arterial relaxation time, has been identified as a potential indicator for inferring the elasticity of arteries. Preliminary measurements of arterial relaxation time of six normotensive subjects are significantly less than measurements of four hypertensive subjects.
Assuntos
Artérias/patologia , Aterosclerose/fisiopatologia , Artéria Braquial/patologia , Artérias Carótidas/fisiologia , Hipertensão/diagnóstico , Hipertensão/fisiopatologia , Adulto , Aterosclerose/diagnóstico , Aterosclerose/patologia , Pressão Sanguínea , Artéria Braquial/metabolismo , Artérias Carótidas/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Obesidade/diagnóstico , Obesidade/fisiopatologia , Fatores de TempoRESUMO
More marginal results and complications occur as a result of knee ligament surgery than of other common surgical procedure. Long-term success rates of anterior cruciate ligament reconstruction range between 75 and 90%. The goal of knee surgery is to restore the normal kinematics of the knee. If the tension is too high, the range of motion of the joint is restricted, resulting in abnormal stresses on the articular cartilage and the meniscuses, and interfering with the revascularization of the graft. The use of Raman spectroscopy for the measurement of tension in ligaments and tendons is described. Measurements of the Raman spectrum demonstrate that the Raman frequencies shift with applied tension.
Assuntos
Ligamento Cruzado Anterior/fisiopatologia , Ligamento Cruzado Anterior/cirurgia , Articulação do Joelho/fisiopatologia , Articulação do Joelho/cirurgia , Ligamentos/patologia , Análise Espectral Raman/métodos , Animais , Fenômenos Biomecânicos , Colágeno/química , Instabilidade Articular/fisiopatologia , Instabilidade Articular/cirurgia , Vison , Ligamento Patelar/transplante , Coelhos , Amplitude de Movimento Articular , Estresse MecânicoRESUMO
Blood velocity measurements in the skin of pigs are reported. Measurements were obtained using laser speckle contrast analysis with a multiple scattering correction. Laser speckle contrast analysis is a rapid technique for obtaining a velocity mapping of perfused tissue. Measurements of blood velocity in pig skin were obtained using a laser and a monochrome digital camera. Blood velocities were measured in tissue prior to and after elevation of flaps. The effect of Iloprost and nitroglycerine on local blood velocity was also examined in nonexcised tissue.
RESUMO
A simple and effective fringe reduction technique for FM 200 250 laser spectroscopy is discussed. A factor of 20 fringe reduction was observed in two-tone FM spectroscopy of water vapor. Theoretical simulations are compared to the exere perimental results.
RESUMO
A generalized theory for optical heterodyne spectroscopy with phase modulated laser radiation is used which allows the calculation of signal line shapes for frequency modulation spectroscopy of Lorentzian gas absorption lines. In particular, synthetic spectral line shapes for both single-tone and two-tone modulation of leadsalt diode lasers are presented in which the contributions from both amplitude and frequency modulations are included.