NASA Scientific and Technical Aerospace Reports

20040046872 Sichuan Univ., Chengdu, China
Study on Increasing Bioactivity of Hydroxy-poly-calcium Sodium Phosphate Appatite Modified by Cold Plasma
Technique
Su, Bao-hui; Ran, Jun-guo; Chen, Zhi-qing; Space Medicine and Medical Engineering, Volume 16, No. 1; February 2003,
pp. 68-71; In Chinese; See also 20040046857; Copyright; Avail: Other Sources
The objective of this research is to improve the bioactivity of hydroxyl-poly-calcium sodium phosphate appatite (HPPA)
by surface modification using cold plasma technique. Surface modification of HPPA was done with cold plasma technology,
structure change and the best technological parameters of HPPA were analysed and its bioactivity was determined by protein
absorption and osteoblast culture in vitro. The best technological parameters of HPPA are: power 370 W; flow capacity
NH3:200 ml/min N2: 100 ml/min; time 60 min. The - NH2,-OH were led into materials. The method of protein absorption
and osteoblast culture in vitro shows: modified HPPA can promote osteoblast growing and increase the activity of AKP. After
modification, the -NH2,-OH were led into HPPA. Bioactivity of the material was increased.
Derived from text
Cold Plasmas; Sodium Compounds; Calcium Phosphates; Activity (Biology); Polymers; Hydroxyl Compounds
20040046875 Institute of Space Medico-Engineering, Beijing, China
A Simulation Study on Cardiac Assist Device: Hemopump
Li, xiong; Bai, Jing; He, Ping; Space Medicine and Medical Engineering, Vol. 16, No. 1; February 2003, pp. 55-59; In
Chinese; See also 20040046857; Copyright; Avail: Other Sources
The objective of this research is to study the interaction between HP31 Hemopump system and the cardiovascular system.
A dynamic model for a HP31 Hemopump system was developed basing on theoretical analysis and experimental data. By
incorporating the Hemopump model in a previously established model for the canine circulatory system, the effects of the
pump on various hemodynamic variables of the circulatory system were investigated and the benefit of the pump to a failing
heart was demonstrated. In addition, different mechanisms of the Hemopump and IABP that relieve the workload of left
ventricle were compared. Our results verified that the Hemopump assists a failing heart by increasing the oxygen supply to
the heart while reducing its oxygen consumption through a reduction in the preload of left ventricle. These beneficial effects
are generally enhanced when the pump’s rotation speed is increased. However, when the pump rotation speed is too high, the
inflow to the pump may be impaired and the pump performance will be negatively affected. Predications from the model are
in good agreement with the results previously obtained in animal experiment and in vitro measurements. The model described
in this paper should provide a useful tool to investigate and test various strategies for optimal control of the Hemopump.
Author
Cardiovascular System; Circulatory System; Hemodynamic Responses; Simulation; Mathematical Models; Blood Pumps
20040046876 Institute of Space Medico-Engineering, Beijing, China
Measurement and Analysis of Operation Performance of the ‘Endocare’ Cryoprobe System
Yu, Tian-hua; Wang, Hong-wu; Zhou, Yi-xin; Liu, Jing; Feng, Hua-song; Lu, Hai-ying; Space Medicine and Medical
Engineering, Vol. 16, No. 1; February 2003, pp. 60-63; In Chinese; See also 20040046857; Copyright; Avail: Other Sources
The objective of this research is to test the working performance of the Endocare Cryoprobe System and to evaluate its
advantages and shortcomings for clinical application in targeted tumor treatment. The cryoprobe was placed into air, distilled
water, and rabbit tissues to observe its freezing and rewarming behaviors. The transient temperatures at the exterior wall and
interior of the cryoprobe were monitored. The output performance of the cryoprobe and the consumption rate of the working
gases were evaluated basing on the measurements. The temperature at the cryoprobe tip inserted into tissues decreased quickly
to its lowest value and kept relatively stable during freezing. The iceball grew quickly at the initial period of freezing and then
slowed down. The temperature at the cryoprobe tip increased quickly when the working gas was shifted to He. In several
minutes, the iceball became thawed. The consumption rate of Ar and He gases decreased with the operation of the cryoprobe.
The Endocare Cryoprobe System had excellent performances in quick freezing and rewarming. However, it also has certain
disadvantages, which were briefly discussed in this paper.
Derived from text
Cryogenics; Probes; Tissues (Biology); Tumors; In Vivo Methods and Tests
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