• Journal of Korean Foot and Ankle Society
• /
• v.17 no.3
• /
• pp.189-195
• /
• 2013

Purpose: We investigated a statistical difference of tibial-articular surface (TAS) angles between radiographs of standing ankle anteroposterior (AP) and whole lower extremity view, and evaluated whether the tibial axis obtained from the standing ankle AP view reflects the original mechanical axis of lower extremity. Materials and Methods: Both the standing ankle AP and whole lower extremity view were taken from 60 legs of 30 healthy volunteers without a history of ankle surgery or deformity of lower limb. To determine the tibial axis, Takakura's and Hintermann's method were employed in the standing ankle AP view. To compare these results with the original TAS angle, ANOVA and multiple comparison test were used. Results: The mean TAS angle was 88.3 degrees(from hip joint to ankle), 89.5 degrees (from knee joint to ankle), 88.5 degrees (Takakura's method), and 90.2 degrees(Hintermann's method). Although there was a statistical significance (p=0.000) between these results, Takakura's method had no significant difference, compared to the results of whole extremity view by the multiple comparison test. Conclusion: The tibial axis obtained by Takakura's method reflects the original mechanical axis of lower extremity. When a surgical procedure is planned, however, it is necessary to consider that the ankle radiographs do not provide any information on the proximal deformity without the whole lower extremity view.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.29 no.2
• /
• pp.417-422
• /
• 1999

Purpose : The aim of this study was to assess the validity of standard deviation of gray scale histogram in digital subtraction radiography as a test parameter for superimposition error. Materials and Methods : Twenty periapical radiographs were used as baseline images and they were copied to exclude the influence of exposure geomety and contrast differences. These subsequent images were linearly displaced by 0.1-0.5 mm in the x-. y- and xy-directions, rotated by 0.5-3° and distorted by angular contraction of 1-5° in x- and y-axis before subtraction. The standard deviations of gray levels in the subtraction images were obtained and paired t-tests were performed. Pearson correlation coefficients(r) were calculated between the standard deviations and the superimposition errors. Results : Linear displacement showed high correlation coefficients of 0.997, 0.997 and 0.995 in x-. y- and xy-axis respectively. Statistically significant different standard deviation existed among all linearly displaced groups(p<0.05). Distortion showed relatively low correlation coefficients of 0.982 and 0.959 in x- and y-axis. The standard deviations between the two distortion groups were statistically significant different(p<0.05). Conclusion : Standard deviation of gray level distribution in digital subtraction images is satisfactory but not perfect similarity measure to assess the superimposition errors.

• The KSFM Journal of Fluid Machinery
• /
• v.16 no.3
• /
• pp.5-9
• /
• 2013

In this study, operational vibration experiment and analysis have been conducted for the 4-blade small vertical-axis wind turbine (VAWT) including the effect of tower elastic behavior. Computational structural dynamics analysis method is applied to obtain Campbell diagram for the VAWT with elastic tower. An open type wind-tunnel is used to change and keep the wind velocity during the ground test. Equivalent elastic tower is used to support the VAWT so that the effect of elastic stiffness of the tower can be considered in the present vibration experiment. Various excitation conditions with wind loads are considered and the dominant operating vibration phenomena are physically investigated in detail.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.4
• /
• pp.269-273
• /
• 2001

W fabricated thin film using Na$_{0.5}$K$_{0.5}$NbO$_3$ volatile material by pulsed laser deposition (PLD) and studied characterization from EM, XRD, P-E. The density and scale of droplet, which is the defect of PLD, was investigated by SEM but large droplet was not found. The degree of assemble oriented C-axis measured with X-ray diffraction suggests that this film oriented C-axis achieved by $\theta$-2$\theta$ scan and rocking curves shows good self-assemble phenomenon, finally $\phi$-scan does that all of the four directions of the lattice in film equals to those of substrate. P-E hysteresis loop shows residual remnant polarization or saturation polarization value, but it is applicable to memories.ies.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.2
• /
• pp.291-297
• /
• 2003

While making diagnosis and the treatment plan for the growing children who visited at Chonnam National University Hospital for orthodontic treatment, authors obtained 8 lateral cephalometric measurements in antero-posterior and vertical relationship such as APDI, WITS, ANB, SN-MP, ODI, PFH/AFH, Y-axis, SUM for children aged 7 to 9 with class III malocclusion and compared them with these of 73 children of elementary school aged 7 to 9 with proper profile and normal occlusion in Gwangju. The results were as follows: 1. Between normal occlusion and class III malocclusion, ANB, SN-MP, ODI, SUM, except PFH/AFH and Y-axis showed statistically significant differences(p<0.05). 2. Between mesurements to describe skeletal disorder of antero-posterior relationship such as APDI, WITS, ANB and skeletal disorder of vertical relationship such as SN-MP, ODI, PFH/AFH, Y-axis, SUM, all of them in both normal occlusion and Class III malocclusion showed significant correlation, except Y-axis, SUM correlation(p<0.01). 3. Wald' statistics of WITS, ANB and APDI expressing skeletal disorder of antero-posterior relationship showed 7.118, 5.148, 0.741, respectively and Wald' statistics of ODI, Y-axis, PFH/AFH, SN-MP, SUM were presented 28.348, 2.238, 1.376, 0.090, 0.089, respectively. Therefore, WITS and ODI could be considered as useful diagnotic measurements for class III malocclusion.

• BMB Reports
• /
• v.57 no.5
• /
• pp.238-243
• /
• 2024

Bone marrow-derived mesenchymal stem cells (BM-MSCs) can differentiate into endothelial cells in an inflammatory microenvironment. However, the regulatory mechanisms underlying this process are not entirely understood. Here, we found that TIE2 in BM-MSCs was upregulated at the transcriptional level after stimulation with tumor necrosis factor-alpha (TNFα), a major pro-inflammatory cytokine. Additionally, the STAT-binding sequence within the proximal region of TIE2 was necessary for TNFα-induced TIE2 promoter activation. TIE2 and STAT3 knockdown reduced TNFα-induced endothelial tube formation in BM-MSCs. Among the major TNFα-activated MAP kinases (ERK1/2, JNK1/2, and p38 MAPK) in BM-MSCs, only inhibition of the p38 kinase abrogated TNFα-induced TIE2 upregulation by inhibiting the JAK-STAT signaling pathway. These findings suggest that p38 MAP contributes to the endothelial differentiation of BM-MSCs by activating the JAK-STAT-TIE2 signaling axis in the inflammatory microenvironment.

• The korean journal of orthodontics
• /
• v.34 no.6 s.107
• /
• pp.497-505
• /
• 2004

The purpose of this study was to evaluate the post-retention stability of the lower incisor axis in Class II division 2 malocclusions. The dental casts and lateral cephalograms from before (T1) and after (T2) orthodontic treatment and long-term post-retention (T3) in 62 Class II division 2 malocclusion cases were included in this study. After several linear and angular measurements at each time were taken, the significance in the amount of change of the lower incisor axis for each gender and extraction versus non-extraction was evaluated. The results showed that the lower incisors that inclined labially during treatment were unstable and relapsed to the original lingual position in Class II division 2 malocclusions (p<0.001). There was no significant difference between extraction and non-extraction groups for the amount of lingual relapse of the lower incisors (p>0.05). There was no significant difference between male and female groups for the axial change of the lower incisors (p>0.05). As a result of multiple regression analysis, the cephalometric measurement best predicting the lower incisor position to the A-Pog line post-retention was pre-treatment L1-Apog(mm) and pre-treatment SNGoMe$(^{\circ})$. Because of the instability of labially inclined lower incisors after orthodontic treatment, the treatment goal should be the pre-treatment incisor axial position.

• 한국체육학회지인문사회과학편
• /
• v.55 no.6
• /
• pp.749-757
• /
• 2016

The purpose of this study was to investigate the effect of stability on one leg standing posture in yoga practice. Thirteen women college student who have never done yoga participated in this study. In order to collect data before and after yoga practicing for two years, we were used 3D motion capture system and electromyography. The results were as follows. First, ranges of motions for Y axis of left knee joint and X axis of right ankle joint were significantly different in dancer posture(p<.05), and then X axis of right ankle and Y axis of left ankle joint were significantly different in tree posture of pre and post training. Second, the planar alignment angle of trunk-pelvis was not significant difference in dancer and tree posture. Third, CoM-distances of Y, Z directions were significant difference in the tree posture(p<.05). Fourth, Muscle activities of both rectus abdominis, erector spinae and left quadriceps were significant difference in tree posture(p<.05). These findings suggested that yoga training played important roles in stable postures as results of decreasing rotation ankle joint and movement of CoM and enforcing core muscles. This study provides evidence for effectiveness of the stability on standing posture and can get a great effect on posture correction by means of yoga training. Hereafter, study on alignment angle, which is a measurement of postural stabilization will be needed by future yoga training.

• Journal of Korean Ophthalmic Optics Society
• /
• v.11 no.3
• /
• pp.275-280
• /
• 2006

For this study, we analysed the difference of values between noncycloplegic and cycloplegic autorefraction in primary school children. We classified the elementary school one, two, three grade (8~10age) 79children(158eyes) who did not have strabismus or amblyopia. They were examined by using the Autorefractor in domestic market before and after cycloplegic. Discrepancies beyond 0.50D in spherical and cylindrical power and 20 degree in cylindrical axis were regarded as significant. The percentages of discrepancy were greater in spherical power between noncydoplegic and cycloplegic autorefraction(p<0.05). The percentages of discrepancy were not greater in cylindrical power between noncycloplegic and cycloplegic autorefraction. The percentages of discrepancy were greater in cylindrical axis between noncydoplegic and cycloplegic autorefraction(p<0.05). In conclusion, for the primary school children who did not wear glasses, the prediction table of this study will be helpful to reduce the test error in visual acuity and refractive error tests.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.3
• /
• pp.291-295
• /
• 2013

Purpose: The purpose of this study was to investigate the effect of under and over refractive correction on visual acuity performance and the variation of the visual performance measurement using two different visual acuity charts. Methods: Ten young adults, aged between 19 and 25 years old, were recruited. Inclusion criteria: no history of ocular injury or pathology with a best-corrected visual acuity of 6/6 on dominant eye. The over and under refractive corrections were induced using minus and plus spherical ophthalmic lenses in 0.50 D steps up to 3.00 D; as well as using three axis orientations of cylindrical ophthalmic lenses ($45^{\circ}$, $90^{\circ}$ and $180^{\circ}$) in 0.50 D steps. The variation of visual acuity performance measurements was investigated using Bailey-Lovie LogMAR chart and Landolt C chart. Results: The visual acuity changes with lenses were significantly different between two charts [F = 49.15, p < 0.05 with plus spherical ophthalmic lenses and F = 174.38, p < 0.05 with minus spherical ophthalmic lenses]. The visual acuity changes with three different cylindrical axis showed no significant difference between Bailey-Lovie LogMAR chart [F = 2.35, p > 0.05] and Landolt C chart [F = 3.12, p = 0.05]. Conclusions: The over and under refractive correction affected the visual acuity performance differently. The Landolt C chart and Bailey-Lovie LogMAR chart demonstrated variation in measurements.