• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.1-15
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• 1997

Titanium oxide films were prepared by ion beam enhanced deposition where the films were synthesized by deposition titianium atoms and simultaneously bombarding with xenon ion beam at an energy of 40 keV in an $O_2$ environ,ent. Structure and composition of titanium oxide films were investigated by X-ray Doffractopm (XRD) Ritjerfprd Backscattering Spectroscopy (RBS) and X-ray Diffraction(XRD) Rutherford Backscattering Spectroscopy (RBS) and X-ray photoelectron spectroscopy (XPS) The results show that thestructure of the prepared films exhibit a rutile phase structure wit high(200) orientation and the O/Ti ratio of the titanium oxide films was about 2:1 XPS anlysis shows that $Ti^{2+},Ti^{3+}\;and\;Ti^{4+}$ chemical states exist on the titanium oxide films. the blood compatibility of the titanium oxide films was studied by measurements of blood clotting time and platelet adhesion. The results show that the anticoagulation property of titanium oxide films improved significantly and better than that of LTI-carbon which was widely used to fabricate artificial heart valve.

• Journal of Veterinary Clinics
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• v.14 no.2
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• pp.201-207
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• 1997

This study was carried out to investigate the changes of blood chemical values in 61 crossbred calves at 1 day, 1 week, 2 weeks, 4 weeks and 9 weeks of age, respectively. The blood chemical values of calves with diarrhea were compared with those of normal calves, and blood chemical values were compared for groups of calves with weight gain divided into four ranges; up to 0.9 kg/wk and over 7.0 kg/wk. The results obtained in this study show that the mean values and standard deviation of red blood cell (RBC) and packed cell volume (PCV) of normal calves at 1 day of age (806.7$\pm $56.5 10$^{4}$/$\mu$l and 33.8$\pm $5.2 %) decreased at 1 week of age and increased at 2 and 4 weeks of age. The PCV of normal calves at 9 weeks of age (32.6$\pm $2.3 %) was significantly lower than that at 2 and 4 weeks of age (p<0.05). Total protein of normal calves at 1 day of age (6.8$\pm $0.5 g/100 ml) decreased to 6.4$\pm $0.6 g/100ml at 1 week and increased to 7.0$\pm $ 0.7 g/100 ml at 2 weeks. After 2 weeks of age, total protein tended to decrease gradually to 9 weeks of age. Glucose of normal calves at 9 weeks of age (78$\pm $4 mg/100 ml) was significantly lower than that at 1 week (110$\pm $8 mg/100 ml) (p<0.01). At all ages, RBC, white blood cell (WBC), PCV and fibrinogen of calves with diarrhea were higher than those of normal calves. RBC and PCV of calves with diarrhea at 1 week of age (929.7$\pm $39.7 10$^{4}$/$\mu$ and 42.3$\pm $0.4 % were significantly higher than those of normal calves at 1 week (786.4$\pm $80.9 10$^{4}$/$\mu$l and 32.2$\pm $3.8 %) (p< 0.05), which suggest that diarrhea at this age can be dangerous. The weekly weight gain was an average of 4.2 kg/wk from birth to 9weeks. RBC, PCV, fibrinogen, total protein and vitamin E of calves with weight gain more than 4.0kg/wk. From the above results we obtained eledata support the importance of providing high quality feed from 4 weeks to 9 weeks of age for satisfactory weight gain of calves.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.418-426
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• 2006

In the artificial heart application, productivity and hemodynamic properties of artificial heart valves are crucial in successiful application to long term in vivo trials. This paper is about manufacture and assessment of trileaflet polymer heart valves using vacuum forming process(VFP). The VFP has many advantages such as reduced fabrication time, reproducibility due to relatively easy and simple process for manufacturing. Prior to VFP of trileaflet polymer heart valves, polyurethane(Pellethane 2363 80AE, Dow Chemical) sheet was prepared by extrusion. The sheets were heated and formed to mold shape by vacuum pressure. The vacuum formed trileaflet polymer heart valves fabrication is composed of two step method, first, leaflet forming and second, conduit forming. This two-step forming process made the leaflet-conduit bonding stable with any organic solvents. Hydrodynamic properties and hemocompatibility of the vacuum formed trileaflet polymer heart valves was compared with sorin bicarbon bileaflet heart valve. The percent effective orifice area of vacuum formed trileaflet polymer heart valves was inferior to bileaflet heart valve, but the increase of plasma free hemoglobin level which reflect blood damage was superior in vacuum formed trileaflet polymer heart valves Vacuum formed trileaflet polymer heart valves has high productivity, and superior hemodynamic property than bileaflet heart valves. Low manufacturing cost and blood compatible trileaflet polymer heart valves shows the advantages of vacuum forming process, and these results give feasibility in in vivo animal trials in near future, and the clinical artificial heart development program.