The purpose of this study was to evaluate biomechanical properties of anterior cruciate ligament (ACL) by the tensile and the relaxation tests. Sixteen pieces of porcine femur-ACL-tibia complex (FATC) were tested. The static tensile and stress relaxation tests were performed with an Instron-type universal testing machine. Differences in stress-strain relation were measured at the slow(100mm/min) and fast (200mm/min) deformation rates. The results are as follows. 1 ) The ACL AM ( anteromedial ) bundle exhibited significant distribution of the deformation at the two deformation rates. 2 ) Significant difference was observed between proximal and midsubstance region at the two (slow and fast) deformation rates. 3 ) Stress relaxation test result was in good agreement with quasi-linear viscoelastic theory.

View full abstract

Total Liquid Ventilation (TLV) is an effective treatment for severe respiratory failure, however, TLV still remains the problem of CO₂ removal. In this study, the membrane oxygenator for TLV (TLV-OX) was developed to introduce into the recirculation TLV system. The in-vitro experiment with the recirculation TLV system were conducted as TLV-OX performance evaluations. The experiment was performed for 1 hrs with 40 mL tidal volume, respiratory rate of 8 breath.min^-1, I:E ratio of 1:1 and Perfluorocarbon(PFC) flow rate of 1.5 L.min^-1. As the result, PpO₂ and PpCO₂ were kept in the normal value (PpO₂ > 400 mmHg, PpCO₂ < 5 mmHg). On receiving the results we conducted ex-vivo evaluation experiments by the use of living lung. The experiment was performed for 3 hrs with 17 mL.kg^-1 tidal volume, I:E ratio of 1:1 and PFC flow rate of 1.5 L.min^-1. As the result, 3 of 4 rabbits were able to achieve TLV for 3 hrs. And it was possible to maintain PaO₂ 100-500 mmHg, PaCO₂ 35-45 mmHg in newly developed TLV system.

View full abstract

Salivary biomarkers provide valuable information about various health conditions. The purpose of this study is to evaluate the possibility of salivary biomarkers which can be collected noninvasively as the indexes of menstrual cycle. Twenty-eight healthy female subjects were enrolled (33.4 ± 4.8 yr, mean ± SD). Menstrual distress questionnaire (MDQ) was used as an index of the menstrual symptoms in order to compare salivary stress biomarker. The salivary α-amylase activity (SAA)was used as an index of the sympathetic nervous activity. The salivary progesterone was used as an index of the female sex hormone. The results showed a significant correlation between the salivary progesterone concentration during the postmenstrual period and the MDQ scores of the premenstrual and menstrual periods. This correlation followed well with the previous study. We also compared the subtract SAA of postmenstrual period from premenstrual and menstrual periods (ΔSAA) with the MDQ scores. It was found that a significant correlation between the ΔSAA for the night during the premenstrual period and the MDQ scores of premenstrual, menstrual and postmenstrual periods. These results suggested a possibility that the salivary amylase can be used as an index of the menstrual symptoms.

View full abstract

In order to improve safety of powered wheelchairs running on cross sloped surfaces, we have developed a downhill turning prevention control (DTPC) system. The effect of DTPC on wheelchair maneuvering has been quantified and evaluated by an evaluation experiment, where six wheelchair users participated. In this study we characterized in detail DTPC-induced changes of the evaluation measures in order to construct a quantitative criterion for screening target users of DTPC. As a result, we found that DTPC-induced improvement in the total scores of the evaluation measures positively correlated with the total scores without DTPC. The multiple regression analysis revealed that the evaluation measures derived from the wheelchair behavior without DTPC are secondary factors on the evaluation score improvement in addition to those from the joystick input. The measures without DTPC are likely to negatively correlate with the controlling skills of the drivers. These results of the statistical analyses, therefore, suggest that the benefit from DTPC will be larger as controlling skill of the users is worse.

View full abstract

Clay play is one of the most favorite activities of toddlers. This research intends to determine the basic characteristics of clay play work pieces created by children in nursery school. Work pieces were created by 18 to 35-months-old nursery school children during four sessions of wheat flour clay play activity. Five boys and four girls participated in the activity. To determine the characteristics, exterior dimensions of 73 clay work pieces were precisely measured using a 3D measurement system. Cluster analysis (Ward method, square Euclid distance) was applied to the data. This enabled us to classify the data into five groups. Groups 1 and 2 account for 77% of the total, and they clarified the characteristics of the clay work pieces created. These groups would indicate characteristics of clay play work pieces of toddlers along to their development. The results suggest that these characteristics must be taken into consideration in the designing of toys or tools for toddlers.

View full abstract