• Journal of Life Science
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• v.19 no.10
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• pp.1346-1351
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• 2009

Recent evidence has shown that many pluripotetic neural crest cells are fate-restricted and that different fate-restricted crest cells emigrate from the neural tube at different times. Jin et al. (2001) identified the expression patterns of Wnts and its antagonists at the time that neural crest cells were being specified and suggested that Wnt signaling was involved in the segregation/differentiation of neural crest cells in the trunk in vitro. In this study, we evaluated the effects of Wnt signaling in avian neural crest lineage segregation. To accomplish this, Wnt signaling was disturbed at the time of neural crest segregation and differentiation by grafting Wnt-3a expressing cells and conducting dominant negative glycogen synthase kinase (dnGSK) electroporation. Stimulation of Wnt signaling induced neural crest lineage segregation and melanoblast specification, and increased the expression levels of genes known to be involved in neural crest development such as cadherin 7 and Slug, which suggests that they are involved in Wnt-induced neural crest lineage differentiation into melanoblasts.

• Physical Therapy Korea
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• v.19 no.4
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• pp.55-60
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• 2012

The trochanteric prominence angle test (TPAT) has been used to measure the femoral anteversion angle between the tibial crest and the vertical line. However, the exact anatomical reference of the tibial crest has not yet been identified in the literature. Thus, the purposes of this research were twofold: first, to compare the femoral anteversion angle measured at three different anatomical references of the tibial crest (the proximal tibial crest, the proximal third of tibial crest, and the proximal half of tibial crest) and, second, to determine inter-and intra-rater reliabilities of the femoral anteversion angle measured at these three different anatomical references of the tibial crest during the TPAT. We recruited 14 healthy subjects, and a total of 28 legs were examined. The TPAT was measured using a digital inclinometer. A 1-way repeated-measure analysis of variance was used to compare the femoral anteversion angle measured at three different anatomical references of the tibial crest, and intraclass correlation coefficients (ICCs) were calculated to determine reliability. The femoral anteversion angle measured at the proximal tibial crest was significantly higher than that at the proximal third of the tibial crest and the proximal half of the tibial crest. The inter-and intra-rater reliabilities of femoral anteversion angle were measured at three anatomic references of the tibial crest were all found to be high during the TPAT (ICC=.9 0~.98). In conclusion, clinicians should recognize that the different degrees of the femoral anteversion angle could be measured when different anatomical references of the tibial crest were used, and that reliabilities were high when an exact anatomical reference of the tibial crest was used during the TPAT.

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.17-17
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• 2006

• Animal cells and systems
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• v.6 no.1
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• pp.69-74
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• 2002

Recent evidence has suggested that trunk neural crest cell generally assumed to have equivalent differentiation potentials, demonstrate differentiation bias along the anterior/posterior axis. In amphibian and fish, neural crest cells give rise to three chromatophore types, melanophores, xantho-phores, and iridophores. Each pigment cell type has distinct characteristics but there is speculation about the cellular plasticity that exists among them. Neural crest cells migrate along specific routes, ventromedially and dorsolaterally. Neural crest cells that travel dorsolaterally are the first cells to begin migration in the axolotl and are the major contributors to the visible pigment pattern. Many factors and mechanisms that are responsible for guiding migratory neural crest cells along potential pathways or determining their fate remain unknown. A single lineage of the crest, which becomes restricted to one of the three pigment cell types, gives us the opportunity to examine the existence of neural crest stem cell populations and cellular plasticity. Study presented here showed results from recent in vitro studies designed to identify parameters influencing differentiation events of individual neural crest-derived pigment cell lineages. Melanophore production from neural crest explants originating from different levels along the anterior/posterior axis of wild type-axolotl embryos were compared and demonstrate that the differentiation of melanophores is enhanced in subpopulation of neural crest treated with forskolin. Forskolin (an adenylate cyclase activator) increases intracellular CAMP concentration and eventually activates the protein kinase-A signaling pathway. Melanophore number, melanin content, and tyrosinase activity in explants taken from the anterior-most region of the crest increased significantly in response to forskolin treatment. This study suggests implications of region specific influences and developmental regulation in the development of pigment pattern.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9C
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• pp.889-896
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• 2006

The crest factor distribution of orthogonal frequency division multiplexing (OFDM) symbol sequences is evaluated and it is shown that OFDM symbol sequences with a short period are expected to have a high crest factor. The crest factor relationship between two input symbol sequences, Hamming distance D apart is also derived. Using these two results, we propose two criteria for a phase sequence set of the selected mapping (SLM) scheme and suggest the rows of the cyclic Hadamard matrix constructed from an m-sequence as the near optimal phase sequence set of the SLM scheme.

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.211-211
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• 2005

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1219-1226
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• 2005

In this study, crest settlement characteristics of CFRD (Concrete Faced Rockfill Dam) and ECRD (Earth Cored Rockfill Dam) were analysed through the instrumentation data from representative 7 large dams in Korea. Also, We have studied the effect of valley shape and uniaxial compressive strength of intact rock to better understand the impact of the parent rock strength and the valley shape on the long term crest settlement of CFRDs. From the results, we found that the valley shape and strength of intact rock on crest settlement of dams are an important parameters. As a result, we obtained that the maximum crest settlement of CFRD is larger than that of ECRD and long term crest settlement rate per dam height of rockfill dams is less than 0.60% during service period.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.351-357
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• 2006

In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) subjected to earthquake loading was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam during earthquake loading with this input parameter. From the sensitivity analysis, it was found that the crest displacement of CFR type dam subjected to dynamic loading was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the extent of effect of shear modulus on the displacement at the crest of CFRD due to dynamic loading decreased as maximum amplitude of input acceleration increased.

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.15-18
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• 2011

Purpose: The anterior iliac crest is a common source for autologous cancellous bone graft. For patients who have previously received cancellous bone grafts from bilateral anterior iliac crests, there may be concerns of whether a sufficient quantity of autologous cancellous bone remains for additional grafts without harvesting it from other sites, such as the posterior iliac crest. Methods: We experienced 3 cases of reharvesting in 2 patients. The diagnosis of the first patient was bilateral facial cleft number 3. This patient received bilateral side cleft alveoloplasty with corticocancellous bone graft from the both anterior iliac crest respectively by a previous surgeon. This patient then needed reharvesting of the anterior iliac crest cancellous bone to correct an ongoing skeletal problem for the bilateral cleft. The other patient had bilateral incomplete cleft of the primary palate. This patient received left side cleft alveoloplasty with cancellous bone graft from the right anterior iliac crest. Before the patient could receive the alveoloplasty on the other side, a radial head osteotomy and cancellous bone graft was performed by orthopedic surgeons who then used the remaining left iliac crest in order to treat a pulled elbow. For the completion of the right side cleft alveoplasty, the anterior iliac crest cancellous bone needed to be reharvested. Prior to the reharvesting, a preoperative computed tomography scan of the pelvis was obtained to assess the maturity of the donor site regeneration. The grafts were then taken from site where a greater amount of regeneration was evident. Results: Long term follow ups showed that the grafts were successfully taken. This sufficient volume was obtainable 14 months after the first harvest. Conclusion: Satisfactory results were achieved after the reharvesting of iliac cancellous bone. Thus, it appears that the reharvesting of the iliac bone is a possible alternative to multiple site grafting, use of allograft or bone substitute materials.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.2
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• pp.160-176
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• 2017

The interaction of focused wave groups with a vertical wall is investigated based on the second order potential theory. The NewWave theory, which represents the most probable surface elevation under a large crest, is adopted. The analytical solutions of the surface elevation, velocity potential and wave force exerted on the vertical wall are derived, up to the second order. Then, a parametric study is made on the interaction between nonlinear focused wave groups and a vertical wall by considering the effects of angles of incidence, wave steepness, focal positions, water depth, frequency bandwidth and the peak lifting factor. Results show that the wave force on the vertical wall for obliquely-incident wave groups is larger than that for normally-incident waves. The normalized peak crest of wave forces reduces with the increase of wave steepness. With the increase of the distance of focal positions from the vertical wall, the peak crest of surface elevation, although fluctuates, decreases gradually. Both the normalized peak crest and adjacent crest and trough of wave forces become larger for shallower water depth. For focused wave groups reflected by a vertical wall, the frequency bandwidth has little effects on the peak crest of wave elevation or forces, but the adjacent crest and trough become smaller for larger frequency bandwidth. There is no significant change of the peak crest and adjacent trough of surface elevation and wave forces for variation of the peak lifting factor. However, the adjacent crest increases with the increase of the peak lifting factor.