Bio-Medical Materials and Engineering - Volume 1, issue 2

Authors: Williams, D. F. | Zhong, S. P. | Doherty, P. J.

Article Type: Research Article

Abstract: The mechanical properties of a microporous, electrostatically spun poly (ether urethane-urea), used in the construction of arterial prostheses, have been examined, with particular reference to anisotropic, crack initiation processes and preconditioning. The results demonstrate considerable anisotropy in relation to samples derived from circumferential and longitudinal directions of the tube wall structure related to the spinning process. There is also a considerable difference in crack initiation on inner and outer surface of the arterial wall, again related to the processing conditions. The results provide an important contribution to an understanding of structure-property relationships in microporous arterial prosthesis.

Keywords: microporous arterial prosthesis, anisotropy, crack initiation processes

DOI: 10.3233/BME-1991-1201

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 2, pp. 75-90, 1991

Authors: Lam, F. K. | Chan, F. H. Y. | Poon, P. W. F. | Du, M. H. | Xu, B. Z.

Article Type: Research Article

Abstract: The maximum length sequence (MLS) technique is applied to improve data collection of a clinically important long latency visual potential. Given a limited time for measuring the response and with low number of stimulus presentation, the MLS teclmique exceeded the conventional method of ensemble averaging in attaining a higher signal-to-noise ratio (SNR). The theoretical consideration of such improvement is developed along with the system implementation. Typical examples of the results obtained in a human subject are presented.

Keywords: evoked potential (EP), visual evoked potential (VEP), maximum length sequence or M-sequence (MLS)

DOI: 10.3233/BME-1991-1202

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 2, pp. 91-103, 1991

Authors: Jian, Chunyun | Wang, Gongrui

Article Type: Research Article

Abstract: Diseases of the bile duct system in the digestive system after surgery are common. In order to clarify the cause of these diseases, research on the diseases from a biomechanical perspective is increasing; however, the same cannot be said of biochemical research. In this paper, by using a new, well-devised testing apparatus, specimens extracted from the bile duct system of canine body are tested. The test data are analyzed using the finite deformation theory, and mechanical properties of the bile duct system outside the liver are investigated. The conclusions show that the viscoelasticity of the bile duct system is very …small. In its normal physiological condition, the bile duct wall has an almost uniform distribution of circumferential and longitudinal stress. However, when the diseases of the bile duct system cause high pressure at the bile duct, the circumferential stress and longitudinal stress at the bile inside wall suddenly increase and are much larger than those stresses at the outside wall. The elastic modulus gradually becomes small from the common bile duct and the common hepatic duct to hepatic duct, and the value of elastic modulus for the cystic duct is almost equal to that of the hepatic duct. Show more

Keywords: bile duct system outside the liver, common bile duct, cystic duct, common hepatic duct, hepatic duct, stress distribution, finite deformation theory, incremental elasticity

DOI: 10.3233/BME-1991-1203

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 2, pp. 105-113, 1991

Authors: Sugata, Kiyoshi | Ohnishi, Takashi | Matsumoto, Kazunori

Article Type: Research Article

Abstract: The 5(and 6)-carboxyfluorescein diacetate (C-FDA) is used for a rapid and continuous counting of living cells. Nonfluorescent C-FDA is converted into fluorescent 5(and 6)-carboxyfluorescein (C-F) by the reaction with esterase, which is an enzyme of living cells. The conversion makes it possible to count the number of living cells by detecting fluorescence. Experimental results show that the living cells of beer's yeast, E. coli, and Lactobacillus bulgaricus can be detected by fluorescence. The flow cell system was used to experiment a continuous detection of living cells, so that the number of living cells of beer's yeast can be detected continuously. …The proposed method can be applied to the on-line counting in the food plants. Show more

Keywords: living cell, rapid counting, C-FDA, continuous counting, flow cell system

DOI: 10.3233/BME-1991-1204

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 2, pp. 115-125, 1991

Authors: Yokobori, Jr., A. Toshimitsu | Ohkuma, T. | Yoshinari, H. | Yokobori, T. | Ohuchi, H. | Mori, S.

Article Type: Research Article

Abstract: In the present paper a method is proposed to measure the degree of the degradation of the elasticity in natural blood vessel and the related materials by using ultrasound Doppler effect. It was found that the deformation rate and its acceleration in the radial direction of the blood vessel can be detected by acoustical imaging and processing using this method. These results were proven to correspond to the degree of the degradation of the elasticity, that is, the degree of viscoelasticity in the blood vessel from the wave versus time pattern detected and its simple analysis. This method was applied …to predicting the arteriosclerosis of blood vessels of humans by acoustical imaging and processing uninvadedly, as the characteristics of viscoelasticity in blood vessels. Show more

Keywords: mechanical degradation of the artery, viscoelasticity, aneurism, arteriosclerosis, diagnosing method, ultrasound Doppler effect, imaging and processing

DOI: 10.3233/BME-1991-1205

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 2, pp. 127-136, 1991

Authors: Yokobori, Jr., A. Toshimitsu | Yoshinari, Hiromi | Kowata, Isao

Article Type: Research Article

Abstract: Biomedical membranes, such as artificial tympanic membranes, are subject to noncontact internal air pressure. To estimate mechanical characteristics of such membranes, it is necessary to carry out the noncontact pressure test and membranous contact test, in addition to the usual monotonic tensile test, by using a rectangular specimen cut from the membranes. In this paper, these mechanical test methods and results on such biomedical membranes were studied. Some of the authors have already presented the mechanical test methods of cellophane membrane for hemodialysis under applied water pressure. Herein, we are concerned with the mechanical test methods of biomedical membranes such …as tympanic membrane, in which gaseous pressure was applied. Show more

Keywords: biomedical membranes, otolaryngology, mechanical properties of soft tissue, test method

DOI: 10.3233/BME-1991-1206

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 2, pp. 137-142, 1991