Biomedical subjects

Qing-Hua Qin

Publications and source records attributed to Qing-Hua Qin.

4 recordsLinked to original sources

PubMed2006

Regional identification, partition, and integral phase unwrapping method for processing moiré interferometry images.

We present a new method of regional identification, partition, and integral (RIPI) phase unwrapping for processing images, especially those with low quality, obtained from moiré interferometry experiments. By introducing the principle of preorder traversal of a general tree in data structures and then by applying the idea of a regional integral, the proposed method makes regional partition and phase evaluation much easier and more accurate, and it also overcomes the common faults that can occur when conventional approaches, such as line defects, are used. Examples are given to demonstrate the advantage and applicability of the proposed RIPI method when processing experimental images. It is shown that the proposed method works well for global phase distribution, and, at the same time, local mutational information is preserved and limited to its vicinity without affecting other parts.

Journal Article↗

PubMed2006

A hypothetical mechanism of bone remodeling and modeling under electromagnetic loads.

A hypothetical regulation mechanism for bone modeling and remodeling under electromagnetic field is proposed. In this hypothesis, the bone modeling and remodeling mechanism is described as follows: the circular loads that we bear during ordinary daily activities generate micro-damage in cortical bone and these micro-cracks are removed by osteoclasts. Then growth factors, which are in latent forms in osteocytes, are activated by osteoclasts and released into bone fluid. These growth factors stimulate osteoblasts to refill the cavities. An electromagnetic field can stimulate the multiplication of growth factors and accelerate the bone remodeling process indirectly. It can be seen that many features reported in adaptive bone modeling and remodeling are explained by the proposed hypothesis. Further, a computational model is established based on the hypothesis, which can simulate the bone modeling and remodeling process under multi-field loads.

Bone Remodeling↗

PubMed2005

Thermoelectroelastic solutions for surface bone remodeling under axial and transverse loads.

Theoretical prediction of surface bone remodeling in the diaphysis of the long bone under various external loads are made within the framework of adaptive elastic theory. These loads include external lateral pressure, electric and thermal loads. Two solutions are presented for analyzing thermoelectroelastic problems of surface bone remodeling. The analytical solution that gives explicit formulation is capable of modeling homogeneous bone materials, while the semi-analytical solution is suitable for analyzing inhomogeneous cases. Numerical results are presented to verify the proposed formulation and to show the effects of mechanical, thermal and electric loads on surface bone remodeling process.

Animals↗

PubMed2004

A micro-mechanics model of dentin mechanical properties.

Application of a micro-mechanics cell model to dentin composites for determination of their effective mechanical properties is discussed in this paper. The dilute micro-mechanics model for fibre-reinforced composites is utilized and the corresponding cell model is chosen to consist of a circular hollow cylinder filled with liquid or gas phase, which is surrounded by two circular cylindrical shells, a thin shell and a matrix phase. Each layer of cylindrical shell is here considered as a composite consisting of collagen fibrils, with mineralized hydroxyapatite, loosely connected to their neighbours, and water (or gas in the case of dry dentin composite). Determination of the effective material properties of such a three phase composite is discussed. Using the cell model the effect of porosity, thickness of each cylindrical shell, and mineral content on material properties is analysed. Results obtained from nano-indentation observations are compared with numerical predictions of the analytical model.

Algorithms↗