• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.9-15
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• 2017

Recently, flexible cages have been introduced in an attempt to absorb and reduce the abnormal load transfer along the anterior parts of the spine. They are designed to be used with the pedicle screw systems to allow some mobility at the index level while containing ROM at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the flexible cage when combined with pedicle screws with flexible rods. The post-operated models were constructed by modifying the L4-5 of a previously-validated 3-D FE model of the intact lumbar spine (L2-S1): (1) Type 1, flexible cage only; (2) Type 2, pedicle screws with flexible rods; (3) Type 3, interbody fusion cage plus pedicle screws with rigid rods; (4) Type 4, interbody fusion cage plus Type 2; (5) Type 5, Type 1 plus Type 2. Flexion/extension of 10 Nm with a compressive follower load of 400N was applied. As compared to the Type 3 (62~65%) and Type 4 (59~62%), Type 5 (53~55%) was able to limit the motion at the operated level effectively, despite moderate reduction at the adjacent level. It was also able to shift the load back to the anterior portions of the spine thus relieving excessively high posterior load transfer and to reduce stress on the endplate by absorbing the load with its flexible shape design features. The likelihood of component failure of flexble cage remained less than 30% regardless of loading conditions when combined with pedicle screws with flexible rods. Our study demonstrated that flexible cages when combined with posterior dynamic system may help reduce subsidence of cage and degeneration process at the adjacent levels while effectively providing stability at the operated level.

• YAKHAK HOEJI
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• v.51 no.6
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• pp.415-423
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• 2007

This study was to evaluate the genotoxic effects of airborne particulate matters using single cell gell elec trophoresis (comet assay) in A549 human lung carcinoma cells. The total suspended particulate (TSP) was collected on back-up filter in Chuncheon, Kangwon Do, South Korea from April, 2003 to February, 2005. The concentrations of TSP, B(a)p and most of heavy metals seemed to be higher in spring and winter, and lower in summer. And they showed higher concentration in the commercial areas and the residential area having more traffics than in the rural area. It was found that A549 cells interacting with the organic extract of TSP showed more DNA single-strand breaks compare to untreated cells. The genotoxicity of the organic extract of TSP was increased with the pre-treatment of S-9 mixture during the culture or with the treatment of endonuclease after cell lysis. The DNA damage by the organic extract of TSP was higher in winter and the commercial area than in summer and the rural area. This study suggests that TSP, heavy metals and B(a)P analyzed showed significant variation depend on the seasons and the areas which are correlated with the DNA damage evaluated by Comet assay, indicating that genotoxic biomarker is useful for toxicological evaluation of air quality.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.662-667
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• 2021

Vibrotactile feedback is a major function of the latest touch displays, which greatly improves the user's operability and immersion when interacting with the interface on the screen. In this study, we propose a vibrotactile actuator suitable for mounting on the back side of a mid- to large-sized display because it can generate a strong vibration output by applying an electrostatic force-based mechanism and can be manufactured in a thin flat panel type. The proposed actuator was developed in a structure capable of amplifying the vibration force by alternating up and down with electrostatic force by the upper and lower electrodes that are spaced apart from the electrically grounded mass suspended from a radial leaf spring. As a result of the performance evaluation, the developed bar-type module with two built-in actuators showed excellent vibration output of up to 3.3 g at 170 Hz, confirming the possibility of providing haptic feedback in medium and large touch displays.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.1
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• pp.101-106
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• 2004

The process of removal of gummy proteinous material sericin from silk is commonly called as degumming loss or boil-off loss ratio. In the present study, the boil-off loss ratio in the cocoon shells of twelve multivoltine${\times}$bivoltine hybrids and their parents were analysed. Inheritance pattern of boil-off loss ratio was analysed in crosses involving high and low boil-off loss parents, F$_1$s, F$_2$s and back-crosses by parent off spring regression analysis. Heterosis and heterobeltiosis was also analysed for this character, Highly significant (P＞0.01) variations were observed in eight out of ten multivoltine and two out of five bivoltine parents indicating the presence of genetic variation in the expression of boil-off loss ratio. Among F$_1$ hybrids, ten hybrids expressed significant (P＞0.01) variations when compared with control hybrid PM${\times}$NB$_4$D$_2$. Significant negative heterosis was expressed in three multi ${\times}$ bi hybrids viz., BL67${\times}$CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{19}$, which is desirable for this character, whereas expression of heterobeltiosis was significant only with one hybrid, 96C${\times}$CSR$_{18}$ in desired direction. Studies on inheritance pattern showed that the character is heritable and contribution percentage of female and male in the ratio of 50.9: 49.1 and it appears that both the parents are influencing in the expression of boil-on loss ratio in silkworm. Based on the overall performance and evaluation by multiple trait evaluation index and also considering the expression of the boil-off loss ratio three hybrids vix., BL67 ${\times}$ CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{18}$ were found superior and recommended for commercial exploitation.n.ion.n.