• Applied Microscopy
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• v.43 no.1
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• pp.27-33
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• 2013

Inflammatory cells express the inflammatory cytokines and growth factors induced by lipopolysaccharide (LPS). Odontoblasts are located at the pulp-dentin interface and extend their cell processes far into the dentin where they are the first cells to encounter microorganisms or their products. Therefore, this study examined the expression of some growth factors related to the signal pathway, such as growth factor receptor binding protein 2 (Grb2)-Ras in odontoblast-like dental pulp cells, after a treatment with LPS. After 60 minutes, the mRNA and protein expression levels of Grb2 and Ras were higher in the LPS-treated cells than in the control cells. The level of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) mRNA expression was increased significantly to a level similar to that of Grb2 and Ras at 60 minutes. The platelet-derived growth factor-AA (PDGF-AA) mRNA level was expressed strongly in the odontoblast like dental pulp cells without an association with LPS stimulation. Scanning electron microscopy revealed many extensions of the cytoplasmic processes and the number of processes increased gradually at 30, 60 and 90 minutes after LPS stimulation. From these results VEGF and bFGF expression might be induced through the Grb2-Ras signal transduction pathway in LPS treated odontoblasts.

• Journal of Ocean Engineering and Technology
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• v.10 no.1
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• pp.53-64
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• 1996

In this paper, rotating bending fatigue tests have been carried out to investigate the growth behabiors of surface fatigue crack initiated from a small artificial surface defect, that might exist in real structures, on 2024-T3 and 6:4 brass. The test results are analysed in the viewpoints of both strength of materials and fracture mechanics, it can be concluded as follows. The effect of a small artificial surface defect upon the fatigue strength is very large. The sensitivity of 2024-T3 on the defect is higher than that of 6:4 brass. The growth behavior of the surface fatigue crack of 2024-T3 is different from that of 6:4 brass. The growth rate of the surface fatigue crack of 2024-T3 is considerably rapid in the early stage of the fatigue life and apt to decrease in the later stage. It was impossible to establish a unifying approach in the analysis of crack growth begabior of 2024-T3 and 6:4 brass using the maximum stress intensity factor because of their dependence on stress level. But if the elastic strain and cyclic total strain intensity factor range were applied to obtain the growth rate of surface fatigue cracks of the materials, the data were found to be nearly coincided.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1244-1249
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• 2002

Myostatin (growth differentiation factor (GDF)-8), is one member of the transforming growth factor $\beta$ superfamily. Investigations of GDF-8 null mice and double-muscled cattle revealed that GDF-8 has a profound influence upon skeletal muscle growth. Therefore, the GDF-8 effect upon the productive performance of pigs is worth exploring. In the present study, the nucleotide sequences and expression levels of GDF-8 genes in European pigs (Landrace and Duroc) and Asian pigs (Taoyuan and Small-ear) were evaluated. Based upon their genetic background these breeds possess significantly distinct growth rate and muscle productionphenotypes. Our sequence data showed that the nucleotide sequences of European and Asian pigs were 100% similar. Postnatal expression of GDF-8 gene in skeletal muscles, from birth to 12 mo of age, among different breeds was measured. GDF-8 expression levels in the longissimus muscle of neonatal European breed littermates were the highest, however it declined significantly (p<0.05) at 1 and 3 mo, and then increased gradually at 6 to 12 mo. The Asian breeds, however, GDF-8 expression level increased markedly at 3 mo and maintained a constant level thereafter. The results indicate that rather than polymorphism within the GDF-8 functional sequence between European and Asia breeds, it was relative to the gene regulation in postnatal muscle growth.

• Journal of Ocean Engineering and Technology
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• v.1 no.2
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• pp.93-100
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• 1987

Corrosion fatigue cracking of the austenitic stainless steel(bese metal & heat affected zone by TIG weld) was studied experimentally under the environments of various specific resistance and air. The characteristics of corrosion fatigue crack growth rate and the environmental constants of paris' rule were investigated for SUS 304 weldments in the various specific resistance. The influences of stress intensity factor range and corrosion on the crack growth rate were compared. The characteristics of corrosion fatigue cracking for the weldments were inspected from mechanical, electrochemical and microstructural point of view. Main results obtained are as follows: 1) As the specific resistance decreases, the environmental constant C of paris'rule increases(hence the corrosion fatigue crack growth rate is rapid), but the environmental constant m decreases, so the effect of corrosion to the crack growth rate is more susceptible than thet of stress intensity factor range. 2) As the stress intensity factor range decreases, the corrosion fatigue crack growth rate of heat affected zone is more susceptible than that of the base metal. 3) The corrosion fatigue crack growth rate of the heat affected zone is more rapid than that of the base metal, because of the phenomenon of softening and the less noble potential coused by wedlding heat cycle. 4) The corrosion fatigue cracking of SUS 304 weldment appears transgranular fracture.

• International Area Studies Review
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• v.20 no.1
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• pp.147-165
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• 2016

We empirically examine the validity of second generation endogenous growth theory suing 21 OECD countries' panel data(1981~2011). Due to non-stationarity in all variables, we test the cointegrated relationships strongly supporting the semi-endogenous growth model. In the estimation of total factor productivity growth function, the growth of domestic and foreign R&D investment levels statistically significantly affect total factor productivity growth. R&D intensity, however, has significant impacts on the total factor productivity growth only in a few models, and international technology gap also has positive impacts on GDP growth. Thus the semi-endogenous growth model is relatively supported while fully endogenous growth model is weakly and occasionally supported in OECD countries. The policy implication of supporting the semi-endogenous growth model is that the sustaining growth requires increasing R&D expenditures.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.623-634
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• 1995

Periodontitis is characterized by gingival inflammation and results in periodontal pocket formation with loss of the supporting alveolar bone and connective tissue around the teeth. Therapeutic modalities should therefore aim not only at eliminating the gingival inflammatory process and preventing the progression of periodontal disease but also at reestablishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, progenitor cells must migrate to the denuded root surface, attach to it, proliferate and mature into an organized and functional fibrous attachment apparatus. Likewise, progenitor bone cells must also migrate, proliferate, and mature in conjunction with the regenerating periodontal ligament. Significant advances have been made during the last decade in understanding the factors controlling the migration, attachment and proliferation of cells. A group of naturally occuring molecules known as polypeptide growth factors in conjunction with certain matrix proteins are key regulators of these biological events. Of these, the fibroblast growth factor(FGF), platelet-derived growth factor(PDGF) , insulin like growth factor(CIGFs), transforming growth factor(TGFs), epidermal growth factor(EGF) and bone morphogenetic growth factor(BMPs) apper to have an important role in periodontal wound healing. The purpose of this study was to determine the effects of BMP on periodontal ligament cells. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Cultured periodontal ligament cells were treated with BMP. Cellular activities were determined by MTT(3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and ALP(alkaline phosphatase) activity. The results were as follows ; Regardless of cultured time, cellular activities were stimulated by BMP. Also, BMP greatly increased alkaline phosphatase(ALP) in periodontal ligament cells. These results suggest that BMP not only have no cytotoxic effect on periodontal ligament cells, but also have osteogenic stimulatory effect on periodontal ligament cells.

• Journal of Life Science
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• v.22 no.5
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• pp.569-574
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• 2012

This study was conducted to investigate the effect of exercise on oxidative stress, nerve growth, and hepatocyte growth factors in obese children. After 12 weeks of aerobic exercise training, the aforementioned parameters before and after the training were compared. As a result, the nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were shown to be lower in the OT than in the NT before and after the training, respectively ($p$ <0.05). The NGF was shown to have increased in both groups after the training ($p$ <0.05). The hepatocyte growth factor (HGF) was shown to be higher in the OT than in the NT before the training ($p$ <0.05), with no difference found afterwards. The malondialdehyde (MDA), ox-LDL, and 8-OHdG (Oxo-2'-deoxyguanosine) were shown to be higher in the OT than in the NT ($p$ <0.05). For ox-LDL, a difference was found between before and after the training ($p$ <0.05). The results of this study showed that obesity induced oxidative stress and caused the abnormalities of nerve and HGF secretion in obese children, and that the 12 weeks of aerobic exercise increased NGF levels, thereby promoting the development of neurogenesis in children.

• Archives of Plastic Surgery
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• v.40 no.6
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• pp.676-686
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• 2013

Background To overcome the potential drawbacks of a short half-life and dose-related adverse effects of using active transforming growth factor-beta 1 for cartilage engineering, a cell-mediated latent growth factor activation strategy was developed incorporating latent transforming growth factor-${\beta}$1 (LTGF) into an electrospun poly(L-lactide) scaffold. Methods The electrospun scaffold was surface modified with NH3 plasma and biofunctionalised with LTGF to produce both random and orientated biofunctionalised electrospun scaffolds. Scaffold surface chemical analysis and growth factor bioavailability assays were performed. In vitro biocompatibility and human nasal chondrocyte gene expression with these biofunctionalised electrospun scaffold templates were assessed. In vivo chondrogenic activity and chondrocyte gene expression were evaluated in athymic rats. Results Chemical analysis demonstrated that LTGF anchored to the scaffolds was available for enzymatic, chemical and cell activation. The biofunctionalised scaffolds were non-toxic. Gene expression suggested chondrocyte re-differentiation after 14 days in culture. By 6 weeks, the implanted biofunctionalised scaffolds had induced highly passaged chondrocytes to re-express Col2A1 and produce type II collagen. Conclusions We have demonstrated a proof of concept for cell-mediated activation of anchored growth factors using a novel biofunctionalised scaffold in cartilage engineering. This presents a platform for development of protein delivery systems and for tissue engineering.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.1
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• pp.27-34
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• 2009

Angiogenesis is essential for solid tumor growth and progression. Among the pro-angiogenetic factors, vascular endothelial growth factor(VEGF), also known as vascular permeability factor, is the most important as a mitogen for vascular endothelium. The VEGF family of molecules currently consists of six growth factors, VEGF-A, VEGF-B, VEGF-C, VEGF-D, VEGF-E, and placenta growth factor(PlGF). Over-expression of PlGF is associated with angiogenesis under pathological conditions such as ischemia, inflammation, and cancer. Hence, the goal of this study is to identify the correlation of clinicopathlogical factors and the up-regulation of PlGF expression in oral squamous cell carcinoma. We studied the immunohistochemical staining of PlGF, PlGF gene expression and a real time quantitative RT-PCR in 20 specimens of 20 patients with oral squamous cell carcinoma. The results were as follows. 1. In the immunohistochemical study of poorly differentiated and invasive oral squamous cell carcinoma, the high level staining of PlGF was observed. And the correlation between immunohistopathological PlGF expression and histological differentiation of specimens was significant (Pearson correlation analysis, significance [r] >0.6, P < .05). 2. In the PlGF gene RT-PCR analysis, PlGF expression was more in tumor tissue than in adjacent normal tissue. Paired-samples analysis determined the difference of PlGF mRNA expression level between the cancer tissue and the normal tissue (Student's t - test, P < .05) These findings suggest that up-regulation of the PlGF gene may play a role in progression and local metastasis in invasive oral squamous cell carcinoma.

• Childhood Kidney Diseases
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• v.20 no.1
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• pp.23-28
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• 2016

Purpose: We investigated whether serum levels of insulin growth factor-1 (IGF-1) and insulin growth factor binding protein-3 (IGFBP-3) are valuable in predicting clinical outcomes or are correlated with other laboratory findings in children with Henoch-$Sch{\ddot{o}}nlein$ purpura (HSP). Methods: We examined 27 children who were consecutively admitted to our hospital with HSP between January 2011 and February 2012. Blood tests (C-reactive protein, white blood cell count, platelet count, erythrocyte sedimentation rate, albumin, immunoglobulin A, complement C3, antineutrophil cytoplasmic antibody, IGF-1, IGFBP-3) and urine tests were performed upon admission. IGF-1 and IGFBP-3 were resampled in the recovery phase. Controls included 473 children whose IGF-1 and IGFBP-3 were sampled for evaluating their growth, at the outpatient department of pediatric endocrinology in our hospital. IGF-1 and IGFBP-3 were compared between the HSP children and controls, and between the acute and recovery phases in HSP children. The ability of these values to predict clinical outcomes including renal involvement was analyzed using bivariate logistic regression analysis (BLRA). Results: IGF-1 and IGFBP-3 were not different between the HSP children and controls ($148.7{\pm}117.6$ vs. $69.2{\pm}96.9$, P=0.290: $3465.9{\pm}1290.9$ vs. $3597.2{\pm}1,127.6$, P=0.560, respectively). There was no significant difference in IGF-1 or IGFBP-3 between acute and recovery phases. Based on the BLRA, no variable, including IGF-1 and IGFBP-3, could predict clinical outcomes including the presence of nephritis Conclusion: We concluded that IGF-1 and IGFBP-3 do not predict clinical outcomes of HSP, including renal involvement, in this study.