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1.
Sci Rep ; 7(1): 16688, 2017 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-29192148

RESUMO

The lens provides refractive power to the eye and is capable of altering ocular focus in response to visual demand. This capacity diminishes with age. Current biomedical technologies, which seek to design an implant lens capable of replicating the function of the biological lens, are unable as yet to provide such an implant with the requisite optical quality or ability to change the focussing power of the eye. This is because the mechanism of altering focus, termed accommodation, is not fully understood and seemingly conflicting theories require experimental support which is difficult to obtain from the living eye. This investigation presents finite element models of the eye lens based on data from human lenses aged 16 and 35 years that consider the influence of various modelling parameters, including material properties, a wide range of angles of force application and capsular thickness. Results from axisymmetric models show that the anterior and posterior zonules may have a greater impact on shape change than the equatorial zonule and that choice of capsular thickness values can influence the results from modelled simulations.


Assuntos
Acomodação Ocular/fisiologia , Tecnologia Biomédica/métodos , Cristalino/fisiologia , Modelos Biológicos , Adolescente , Adulto , Simulação por Computador , Análise de Elementos Finitos , Humanos , Lentes Intraoculares , Desenho de Prótese
3.
J Comput Chem ; 29(12): 1876-88, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18381632

RESUMO

A novel algorithmic scheme for numerical solution of the 3D Poisson-Nernst-Planck model is proposed. The algorithmic improvements are universal and independent of the detailed physical model. They include three major steps: an adjustable gradient-based step value, an adjustable relaxation coefficient, and an optimized segmentation of the modeled space. The enhanced algorithm significantly accelerates the speed of computation and reduces the computational demands. The theoretical model was tested on a regular artificial channel and validated on a real protein channel-alpha-hemolysin, proving its efficiency.


Assuntos
Canais Iônicos/metabolismo , Íons/metabolismo , Modelos Biológicos , Algoritmos , Biologia Computacional/métodos , Biologia Computacional/normas , Proteínas Hemolisinas/metabolismo , Tempo
4.
J Chem Inf Comput Sci ; 43(2): 587-94, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12653525

RESUMO

Using a new optical engineering technique for the "fingerprinting" of beverages and other liquids, we study and evaluate a range of features. The features are based on resolution scale, invariant frequency information, entropy, and energy. They allow mixtures of beverages to be very precisely placed in principal component plots used for the data analysis. To show this we make use of data sets resulting from optical/near-infrared and ultrasound sensors. Our liquid "fingerprinting" is a relatively open analysis framework in order to cater for different practical applications, in particular, on one hand, discrimination and best fit between fingerprints, and, on the other hand, more exploratory and open-ended data mining.

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