Bio-Medical Materials and Engineering - Volume 4, issue 2

Authors: Yokobori, Takeo

Article Type: Other

DOI: 10.3233/BME-1994-4201

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 67-67, 1994

Authors: Yokobori, Takeo

Article Type: Research Article

Abstract: So-called bioengineering is, indeed, of an interdiscriplinary nature. It covers very huge fields and concerns many various concepts and ideas. Bioengineering, in this sense, appears to include the fields, in terms of terminology, of bioscience, biotechnology, biomaterials, biomechanical behaviour, biomechanics, and so forth. On the other hand, it seems to be difficult to draw distinctions among these fields, as is often the case in such interdisciplinary science and technology. Then the question may arise what are bioengineering, biotechnology, biomaterials, biomechanical behaviour, biomechanics, etc.? Herein, from this point of view, an attempt will be made to consider the interaction among …the concepts and the prevalent approaches in each separate field called biomaterials, biomechanical behaviour, and biomechanics. Also, some approaches and methodologies that remain unknown have been pointed out for future new development of the research in the mechanical behaviour of bio- and biomedical materials and in bioengineering. Show more

Keywords: Zeiryokyodogaku, fractology, nonlinear

DOI: 10.3233/BME-1994-4202

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 69-76, 1994

Authors: Yoshinari, Hiromi | Yokobori, Jr., A. Toshimitsu | Ohkuma, Tsuneo

Article Type: Research Article

Abstract: The method used in this paper is developed to estimate the degree of viscoelasticity of the blood vessel wall in a noninvasive mechanical method. In this proposed method, we can obtain an output waveform connected with mechanical behavior of blood vessels by using Ultrasonic Doppler Effect Sensory (UDES). Characterizing parameters on this waveform are established to estimate the mechanical properties of blood vessels. By analyzing the characteristics of these parameters, we attempt to estimate the viscoelastic property of blood vessels. Previously, it was found that these parameters are related to viscoelastic mechanical properties of materials. In this paper, we carried …out computer analysis on the mechanical viscoelastic model and compared the theoretical behavior of blood vessels with the experimental output waveform by UDES. From these results, it was proved that values of these parameters connect with the change of the viscoelastic mechanical property of blood vessels. Therefore, the characterizing parameters of experimental output waveforms can be used to estimate the viscoelastic property of blood vessels in a noninvasive method. Show more

Keywords: noninvasive estimation, mechanical characteristics of blood vessels, viscoelasticity, theoretical analysis, viscoelastic model, ultrasonic Doppler effect

DOI: 10.3233/BME-1994-4203

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 77-86, 1994

Authors: Yokobori, Jr., A. Toshimitsu | Ohkuma, Tsuneo | Sasaki, Shigeru | Yoshinari, Hiromi | Yokobori, Takeo | Ohuchi, Hiroshi | Mori, Shozo

Article Type: Research Article

Abstract: Previously we proposed Acoustical Imaging and Processing Method to measure the viscoelastic property of the blood vessels of a canine and the related materials using Ultrasonic Doppler Effect Measurement. Furthermore, its theoretical foundation was presented. In this paper, this method is applied to measure the viscoelastic mechanical property, that is, the mechanical degradation of human blood vessels by a percutaneous noninvasive method. Based on these results, we proposed the algorithm of the noninvasive estimation method on the viscoelastic mechanical property of the blood vessel by using Doppler Effect Sensor. This method makes it possible to discriminate the blood …vessel with arteriosclerosis from a normal blood vessel. Clinical applications were successfully performed using our developed computer software based on our proposed algorithm. Show more

Keywords: atherosclerosis, aneurysm, viscoelasticity, noninvasive diagnosis method, ultrasonic doppler effect

DOI: 10.3233/BME-1994-4204

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 87-96, 1994

Authors: Sasaki, Shigeru | Yokobori, Jr., A. Toshimitsu | Ohkuma, Tsuneo

Article Type: Research Article

Abstract: Previously, we developed the noninvasive estimation method on the viscoelastic deterioration of the blood vessel and related materials by using a Ultrasonic Doppler Effect Sensor and we presented its theoretical foundation. Furthermore, we applied this method to discriminate the human blood vessels with atherosclerosis from normal blood vessels, as the viscoelastic deterioration under in vitro condition and proposed the algorithm for its diagnosis. In the present paper, we propose the software for personal computer (AORTA) for clinical diagnosis on the atherosclerosis within a few minutes by using Ultrasonic Doppler Effect Sensor based on this algorithm. Using this software, …we clinically applied this method to patients with atherosclerosis and normal people. It enables us to discriminate the atherosclerotic blood vessels from those of the normal blood vessel within several minutes. By using this system, it is found that the normal human blood vessel has elastic property. When the blood vessel becomes atherosclerotic, it deteriorates in elasticity and shows the viscoelastic property. This system evaluates noninvasively the viscoelastic property of the blood vessel and the degree of the atherosclerosis. Show more

Keywords: noninvasive diagnosis method, CAE software, ultrasonic doppler effect, atherosclerosis

DOI: 10.3233/BME-1994-4205

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 97-103, 1994

Authors: Nakayama, M. | Tanishita, K.

Article Type: Research Article

Abstract: This study propose a new simple method of measuring the thermal diffusivity of living tissue by thermal pulse decay teclmique with focused ultrasonic beam, which does not require the accurate kuowledge of Gaussian variance within the focal region. The measurement of temperatures at two different locations outside the focal region replaces the elaborate measurement of the size of the focal region and gives a thermal diffusivity with reasonable accuracy and automatically avoids the artifact due to beam-thermocouple interaction. The focused ultrasound was generated by the bowl-shaped ceramic piezoelectric transducer with the diameter of 30 mm. The focal lengths of transducer …were 40 mm and 60 mm and the frequencies 1.7 and 3.6 MHz. The values of thermal diffusivity of biological tissues obtained in this method are fairly close to the previously published values and are also compared to the values obtained by heated thermistor method. Show more

Keywords: thermophysical property, thermal diffusivity, focused ultrasonic beams, thermal pulse decay, biomaterial

DOI: 10.3233/BME-1994-4206

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 105-114, 1994

Authors: Ujihira, Masanobu | Aizawa, Naoki | Tanishita, Kazuo

Article Type: Research Article

Abstract: The purpose of this study is to find the feasibility of preservation of large cell and tissue by maintaining the undercooled state in a freezing process, leading to avoiding the growth of ice crystals in the intracellular space, which causes destruction of cell and tissue. The fertilized killifish egg was employed to test biological tissue. The cooling system was equipped with Peltier devices and able to decrease the temperature of the test section to −50°C. The cooling rate could be regulated by the electric current supplied to the Peltier devices. In the temperature range 0 to −40°C, the morphology …of fertilized killifish egg was observed under a microscope with a cooling rate from 0.1 to 10°C/min. The damage rate to the egg in the intracellular undercooled state was evaluated by hatching rate. As a result, intracellular undercooled states were observed in the freezing process with the extracellular undercooling and the extracellular freezing. Extracellular undercooling proves to preserve the egg, and extracellular freezing frequently damages the egg. Thus the cryopreservation of biological material is achieved by maintaining the undercooled state until the temperature of −40°C, then is instantly frozen by the liquid nitrogen to avoid the growth of ice crystals. The maintaining of the stable undercooled state of biological material is requisite for the initial phase in the freezing process. Therefore, dehydration or maintaining the extracellular stable undercooled state should be desirable to maintain the intracellular undercooled state for cryopreservation of biological material. Show more

Keywords: cryopreservation, undercooled state, dehydration, killifish egg, damage

DOI: 10.3233/BME-1994-4207

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 115-125, 1994

Authors: Azuma, Tadanori | Niiro, Masaya | Motobu, Hirotetsu

Article Type: Research Article

Abstract: Many studies have been done on the removal of pollutants from wastewater using aquatic plants. Water hyacinth has been the most widely-used plant, and systems using water hyacinth are well-established. These systems, however, have a few problems in their practical use. In a previous paper, we proposed a new system that could be used as a substitute for a conventional system or, as a secondary system to assist the conventional one. Mung beans will be used to remove pollutants in this system. In the previous experiment, the removal haracteristics of nutrient salts such as NO− 2 , NO− 3 , …NH+ 4 and phosphorus salts from wastewater in residential areas were examined. Mung beans exhibited good characteristics for removing these nutrient salts. At present, pesticides used at golf courses have become a severe environmental problem polluting water supplies. The purpose of this study was, therefore, to verify whether our new system using mung beans was also effective in removing pesticides from wastewater at golf courses. An experiment was conducted on seven different pesticides. They were three insecticides; Diazinon, Fenitrothion and Chlorpyrifos, three fungicides; Captan, Isoprothiolane and Chlorothalonil, and a herbicide; Simazine. The experimental results showed that, under experimental conditions, the pesticides were rapidly removed and that they exhibited no harmful effects on the growth of the mung beans. Mung beans may be used, therefore, to remove pesticides from wastewater at golf courses although further research is needed. Show more

Keywords: environment, wastewater, mung beans, pesticides, golf courses

DOI: 10.3233/BME-1994-4208

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 2, pp. 127-137, 1994