Computer simulation methods of cardiac electrophysiology / 生物医学工程学杂志

Computer simulation is one of the powerful protocols to study electrophysiology theoretically. In this paper,the algorithm of Rush and Larsen was used to solve the ordinary differential equations (ODE's) in the Luo-Rudy models of mammalian ventricular cell. The operator splitting and adaptive time step methods were used to solve the partial differential equations (PDE's) in cardiac tissue conduction models. Using these methods we accomplished the simulation programs of single ventricular cell model and two-dimensional (2-D) tissue model. The methods of initiating spiral waves were studied with this software. The data obtained from 2-D simulation can be used for further study on isopotential contour lines, spiral wave tip trajectories, and pseudo-ECG.

Digital fluoroscopy imaging system with dual energy X-ray image decomposition / 生物医学工程学杂志

Dual-kilovolt technique was realized in dual energy X-ray imaging system with computer controlled KV adjustment, filter switching and image acquirement. The dual energy images can be obtained in 2-3 seconds to avoid moving artifact. Low energy photons in high energy X-ray beam can be attenuated effectively by a 2 mm Cu filter to separate the spectra of the high and low energy X-rays. A simplified dual energy decomposition method was used to obtain the soft tissue image. An example of chest dual energy radiographs is presented to illustrate the performance of the system.

Synthesis and characteristics of porous hydroxyapatite bioceramics / 生物医学工程学杂志

The macroporous structure of human bone allows the ingrowth of the soft tissues and organic cells into the bone matrix, profits the development and metabolism of bone tissue, and adapts the bone to the change of load. There is great requirement for artificial biomimic porous bioactive ceramics with the similar structure of bone tissue that can be used clinically for repairing lost bone. Fine hydroxyapatite (HAp) powder produced by wet chemical reaction was mixed with hydrogen peroxide (H2O2), polyvinyl alcohol, methyl cellulose or other pores-making materials to form green cake. After drying at low temperature (below 100 degrees C) and decarbonizing at about 300 degrees C-400 degrees C, the spongy ceramic block was sintered at high temperature, thus, macroporous HAp bioceramic with interconnected pores and reasonable porosity and pore-diameter was manufactured. This kind of porous HAp bioceramics were intrinsically osteoinductive to a certain degree, but its outstanding property was that they can absorb human bone morphogenetic proteins and other bone growth factors to form composites, so that the macroporous HAp bioactive ceramic has appropriate feasibility for clinical application. From the point of biomedical application, the recent developments in synthesis and characteristics investigation of macroporous HAp are reviewed in this paper.

5-Aminolevulinic acid esters based photodynamic therapy / 生物医学工程学杂志

As exogenous ALA (5-aminolevulinic acid) esters can induce the production and accumulation of endogenous photosensitizer PpIX (protoporphyrin IX) in tumor tissues more effectively, they have been the most active photosensitizer prodrug in PDT(photodynamic therapy) field. In this article, along with the procedure of ALA esters based PDT, some primary mechanism and experimental results were considered, which include: first, cellular uptake of ALA esters and its conversion into ALA; second, the production and accumulation of endogenous photosensitizer PpIX induced by eNdogenous ALA esters; last, the photosensitization of PpIX.

The application and development of artificial intelligence in medical diagnosis systems / 生物医学工程学杂志

This paper has reviewed the development of artificial intelligence in medical practice and medical diagnostic expert systems, and has summarized the application of artificial neural network. It explains that a source of difficulty in medical diagnostic system is the co-existence of multiple diseases--the potentially inter-related diseases. However, the difficulty of image expert systems is inherent in high-level vision. And it increases the complexity of expert system in medical image. At last, the prospect for the development of artificial intelligence in medical image expert systems is made.

Study of functional magnetic stimulation / 生物医学工程学杂志

Functional magnetic stimulation (FMS) is a new technique for stimulation on excitable neuromuscular cell and provides extensive applications with many advantages, such as deep stimulation, less pain, non-invasive approach and easy to operate technique. In this paper, the new reports of FMS are introduced including the principle, stimulator, coils, results of experiments and our research on analgesic effect of FMS.

无创性磁刺激技术及在康复中的应用 / 中国康复理论与实践

@#无创性磁刺激技术在中枢神经功能检测和神经肌肉功能恢复的应用是康复医学工程研究的一个新热点。文章对磁刺激的发生发展 ,物理原理 ,特性 ,磁刺激与标准电刺激的差别 ,外周磁刺激技术的多信道磁刺激对电刺激模拟等最新发展 ,以及临床上磁刺激在神经肌肉功能恢复的作用作了全面介绍。

The electrophysiologic character of epileptic seizure / 中国病理生理杂志

Epilepsy is a family of neurological disorders that are common and harmful to human's health. The etiologies of epilepsy and the clinical manifestations of seizures are complex and various. To elucidate the mechanisms underlying seizure generation, lots of researches in the anatomy, physiology, biochemistry, genetic and molecular biology of epilepsy have been done over many years. However, no single hypothesis provides a unifying framework within which all kinds of epilepsy can be included so far. In fact, the electrophysiologic essence of epileptic seizure is abnormal excess discharges of neurons. On the standpoint of electrophysiology, the reasons of abnormal discharges of neurons are of common character: depolarizing currents with long durations and high amplitudes on cell levels, which is closely related to slow waves with high amplitudes on EEG levels. This can make us understand the mechanism of epileptic seizures better, and is helpful for well control and therapy of seizures.