Comparison of effective phacoemulsification time and corneal endothelial cell loss using three different ultrasound frequencies: A randomized controlled trial

Purpose: Comparison of three ultrasound (US) frequencies for phacoemulsification of hard cataracts to determine a frequency that makes phacoemulsification more efficacious and safer. Methods: A randomized controlled trial was undertaken at a medical college and hospital. In total, 207 patients with grade 5.6� 6.9 (LOCS III) senile cataract were randomized into three groups. Group I underwent phacoemulsification with 28?kHz frequency, group II with 42?kHz frequency, and group III with 53?kHz frequency. The effective phacoemulsification time (EPT) and estimated fluid usage (EFU) were compared intraoperatively. The endothelial cell parameters were analyzed for 6 months. Results: The groups were matched for age (P = 0.467), gender (P = 0.497), nuclear grade (P = 0.321), and anterior chamber depth (P = 0.635). The EPT and EFU were significantly lower in group III, compared to group II and group I, with P < 0.0001 and P < 0.0001, respectively. Postoperatively, the endothelial cell density (ECD) was significantly higher in group III at 1 month (P < 0.0001), 3 months (P < 0.0001), and 6 months (P < 0.0001). The percentages of ECD loss were also significantly lower in group III; the difference was statistically significant (P < 0.0001) up to 6 months postoperatively. Conclusion: Higher frequency ultrasound was associated with a lower EPT and EFU as well as better endothelial preservation than lower frequencies in hard cataracts

Diseño y Evaluación de un micro viscosímetro de bajo costo utilizando un resonador de cristal de cuarzo y Arduino / Designing and evaluating a low-cost micro-viscometer using a quartz crystal resonator (QCR) and an Arduino DUE microcontroller board / Desenho e Avaliação de um micro viscosímetro de baixo custo usando um ressonador de cristal de quartzo e Arduino

Resumen El objetivo principal de este artículo es proponer el diseño de un micro viscosímetro de bajo coste utilizando un resonador de cristal de cuarzo (QCR) y una tarjeta Arduino DUE. En el artículo se explican los pasos del diseño del sensor y también su evaluación con dos líquidos de diferentes características: diluciones de glicerol en agua (comportamiento Newtoniano) y diluciones de albúmina de huevo extraída de huevos frescos en agua (comportamiento No-Newtoniano). Este estudio está relacionado con el interés de desarrollar nuevas herramientas para el diagnóstico de enfermedades cardiovasculares y artríticas.

Abstract This article outlines a design for a low-cost micro-viscometer, using a quartz crystal resonator (QCR) and an Arduino DUE programmable microcontroller board. The article explains the steps involved in designing the sensor and also how it was evaluated regarding two liquids having different characteristics: dilute aqueous glycerol (Newtonian behaviour) and dilutions of egg-white extracted from fresh eggs in water (non-Newtonian behaviour). This study was related to interest in developing new tools for diagnosing cardiovascular and arthritic diseases.

Resumo O principal objetivo deste trabalho é propor o projeto de um micro viscosímetro de baixo custo usando um ressonador de cristal de quartzo (QCR) e um cartão Arduino DUE. O artigo explica as etapas do desenho do sensor e também sua avaliação com dois líquidos de diferentes características: diluições de glicerol em água (comportamento newtoniano) e diluições de albumina de ovo extraídas de ovos frescos em água (comportamento não newtoniano). Este estudo está relacionado ao interesse de desenvolver novas ferramentas para o diagnóstico de doenças cardiovasculares e artríticas.

Mechanical properties of human enamel based on resonant ultrasound spectroscopy / 医用生物力学

Objective To investigate the mechanical properties of human enamel based on resonant ultrasound spectroscopy (RUS). Methods The rectangular parallelepiped specimens of human enamel were processed. The theoretical resonant frequencies of specimens were estimated and paired with the experimental resonant frequencies measured from RUS experiments. An iterative procedure was used to adjust elastic constants of enamel until the theoretical frequencies corresponded to the experimental frequencies based on minimum mean-squared error criterion. In addition, elastic modulus, shear modulus and Poisson’s ratio were calculated respectively. Results The elastic modulus, shear modulus and Poisson’s ratio ranged from 61.52 to 80.46 GPa, 21.51 to 51.86 GPa and 0.18 to 0.43, respectively. Eliminating the effect of large specimen variances, the average of elastic modulus, shear modulus and Poisson’s ratio was 72.84 GPa, 31.94 GPa and 0.27, respectively. Conclusions RUS performs a feasibility of measuring the mechanical properties of human enamel with repeatable and nondestructive advantages. All the elastic constants and mechanical parameters can be estimated through a signal experiment. The results provide references for the development of biomimetic dental restoration materials.

Mechanical properties of human enamel based on resonant ultrasound spectroscopy / 医用生物力学

Objective To investigate the mechanical properties of human enamel based on resonant ultrasound spectroscopy (RUS).Methods The rectangular parallelepiped specimens of human enamel were processed.The theoretical resonant frequencies of specimens were estimated and paired with the experimental resonant fre quencies measured from RUS experiments.An iterative procedure was used to adjust elastic constants of enamel until the theoretical frequencies corresponded to the experimental frequencies based on minimum mean-squared error criterion.In addition,elastic modulus,shear modulus and Poisson's ratio were calculated respectively.Results The elastic modulus,shear modulus and Poisson's ratio ranged from 61.52 to 80.46 GPa,21.51 to 51.86 GPa and 0.18 to 0.43,respectively.Eliminating the effect of large specimen variances,the average of elastic modulus,shear modulus and Poisson's ratio was 72.84 GPa,31.94 GPa and 0.27,respectively.Conclu sions RUS performs a feasibility of measuring the mechanical properties of human enamel with repeatable and nondestructive advantages.All the elastic constants and mechanical parameters can be estimated through a sig nal experiment.The results provide references for the development of biomimetic dental restoration materials.