• Corrosion Science and Technology
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• v.17 no.3
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• pp.91-100
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• 2018

Development of biodegradable implants for treatment of complex bone fractures has recently become one of the priority areas in biomedical materials research. Multifunctional corrosion resistant and bioactive coatings containing hydroxyapatite $Ca_{10}(PO_4)_6(OH)_2$ and magnesium oxide MgO were obtained on Mg-Mn-Ce magnesium alloy by plasma electrolytic oxidation. The phase and elemental composition, morphology, and anticorrosion properties of the coatings were investigated by scanning electron microscopy, energy dispersive spectroscopy, potentiodynamic polarization, and electrochemical impedance spectroscopy. The PEO-layers were post-treated using superdispersed polytetrafluoroethylene powder. The duplex treatment considerably reduced the corrosion rate (>4 orders of magnitude) of the magnesium alloy. The use of composite coatings in inducing bioactivity and controlling the corrosion degradation of resorbable Mg implants are considered promising. We also applied the plasma electrolytic oxidation method for the formation of the composite bioinert coatings on the titanium nickelide surface in order to improve its electrochemical properties and to change the morphological structure. It was shown that formed coatings significantly reduced the quantity of nickel ions released into the organism.

• Archives of Reconstructive Microsurgery
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• v.9 no.1
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• pp.49-55
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• 2000

Nonunion and avascular necrosis are well-recognized complications of severe ankle injury especially aftrer talar neck fracture. The treatment of avascular necrosis is controversial and methods of treatment are limited. Many modalities have been introduced for the treatment of avascular necrosis of talus. The prolonged non-weight bearing for 2~3 years is not practical but also is occasionally complicated by late segmental collapse. Operative treatment includes tibiotalar arthrodesis and talectomy with tibiocalcaneal arthrodesis, but arthrodesis in patients with talar avascular necrosis is technically demanding and cause stiff, immobile foot and relatively high failure rate was reported. It is desirable to preserve their original joint if possible. Vascularized fibular grafting has been reported as a joint preserving treatment option for osteonecrosis of the hip but has not been described for the ankle. The authors applied free vascularized fibular grafts for 3 cases of avascular necrosis of talus. We observed evidences of revascularization of necrotic talar body and progression of fracture healing and obtained satisfactory results at mean 8 months of follow-up. Vascularized fibular grafting is one of the better alternatives for treating avascular necrosis of talus. It is expected that vascularized fibular grafting can prevent the necrotic talar dome from progressing to collapse and promote directly restored vascularization and new bone formation.

• Archives of Reconstructive Microsurgery
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• v.23 no.1
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• pp.1-7
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• 2014

Purpose: Recent studies have reported on application of fibrin glue composed of fibrinogen and thrombin to nerve anastomosis, which can be another candidate for vessel anastomosis. However, no research regarding the risk and effectiveness of thrombin in microvascular free tissue transfer has been reported. Therefore, the aim of study is to determine the risk and effectiveness of thrombin on microvascular free tissue transfer through clinical cases. Materials and Methods: Twenty-five patients underwent free flap reconstruction for soft tissue defect or bone exposure in our institute from March 2011 to February 2014. In the group using thrombin, dissolved powder thrombin (5,000 IU/amp) was mixed with 10 mL normal saline. Saline mixed with thrombin was applied on the flap, recipient, and around vessel anastomosis. In the control group, free flap was performed using the same method, except using thrombin. We analyzed the results between the two groups. Results: All flaps survived. The group using thrombin included 14 patients and the control group included 11 patients. Hematoma was found in two cases, respectively, in each group. The group using thrombin showed lower incidence of hematoma than the control group. No difference in survival rate of the flap was observed between the thrombin group and the control group. Conclusion: Results of this study showed that use of saline mixed with thrombin in free tissue transfer may be safe and effective for prevention of hematoma formation in the recipient site.

• The Journal of Korean Physical Therapy
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• v.21 no.4
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• pp.97-102
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• 2009

Purpose: The purpose of this study was to investigate the effects of low intensity pulsed ultrasound on TGF-$\beta$1 expression and healing of rat femur penetrating fractures. Methods: Rats were anesthetized with ketamine and xylazine. Using aseptic technique, we exposed the lateral right femoral diaphysis with removal of the periosteum. We made one hole along its long axis with an electrically-driven 1.8 mm diameter drill bit. Postoperatively, rats were divided into two groups (a control group, n=15; an experimental group, n=15). The experimental group was treated with low intensity pulsed ultrasound (pulse rate: 1:4, 0.5 W/$cm^2$, 10 minutes, 1 time per day) for 3 weeks. The control group was treated with sham ultrasound (with the US unit turned off). Results: The experimental group achieved more callus formation and TGF-$\beta$1 expression than the control group at the $7^{th}$, $14^{th}$ and $21^{st}$ days after low intensity pulsed ultrasound treatment. Conclusion: This study suggests that low intensity pulsed ultrasound facilitates bone fracture repair, possibly via increased TGF-$\beta$1 expression.

• Biomolecules & Therapeutics
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• v.24 no.1
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• pp.1-8
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• 2016

Alpha-ketoglutarate (AKG) is a key molecule in the Krebs cycle determining the overall rate of the citric acid cycle of the organism. It is a nitrogen scavenger and a source of glutamate and glutamine that stimulates protein synthesis and inhibits protein degradation in muscles. AKG as a precursor of glutamate and glutamine is a central metabolic fuel for cells of the gastrointestinal tract as well. AKG can decrease protein catabolism and increase protein synthesis to enhance bone tissue formation in the skeletal muscles and can be used in clinical applications. In addition to these health benefits, a recent study has shown that AKG can extend the lifespan of adult Caenorhabditis elegans by inhibiting ATP synthase and TOR. AKG not only extends lifespan, but also delays age-related disease. In this review, we will summarize the advances in AKG research field, in the content of its physiological functions and applications.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.851-861
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• 2005

The nature of the implant surface can directly influence cellular response, ultimately affecting the rate and quality of new bone tissue formation. The aim of this in vitro study was to investigate if human osteoblast-like cells, Saos-2, would respond differently when plated on disks of magnesium titanate and machined titanium. Magnesium titanate disks were prepared using Micro Arc Oxidation(MAO) methods. Control samples were machined commercially pure titanium disks. The cell adhesion, proliferation and differentiation were evaluated by measuring cell number, and alkaline phosphatase(ALPase) activity at 1 day and 6 day after plating on the titanium disks. Measurement of cell number and ALPase activity in Saos-2 cells at 1 day did not demonstrate any difference between machined titanium and magnesium titanate. When compared to machined titanium disks, the number of cells was reduced on the magnesium titanate disks at 6 day, while ALPase activity was more pronounced on the magnesium titanate. Enhanced differentiation of cells grown on magnesium titanate samples was indicated by decreased cell proliferation and increased ALPase activity.

• The Journal of the Korean dental association
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• v.54 no.3
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• pp.198-205
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• 2016

The purpose of this paper was to investigate the significance of splinted and non-splinted implant-supported restorations with an internal connection for multiple consecutively missing teeth. Upon examination of the effects of fixture-abutment connection, the distribution of occlusal load was favorable in splinted implant-prosthesis with an external connection, but effect of strain distribution was not significant in splinted implant-prosthesis with an internal connection. In splinted implant-prostheses for short implants, strain distribution was not affected by the method of retention. For cement-retained prostheses, the effect of strain distribution due to splinting was not significant. In clinical studies, non-splinted prostheses with an internal connection for multiple consecutively missing teeth showed high survival rate, mild marginal bone loss, and stable periodontal condition. However, failure to achieve optimal proximal contact between single-unit prostheses may lead to food impaction, and veneer fracture may be inevitable when the framework provides inadequate support in the proximal region. In conclusion, splinted implant-prosthesis is not an indication in all cases, and clinical consideration of its use should be based on the patient's oral condition, such as location and number of implants, formation of proximal contact, canine guidance, existence of parafunctional habit, and oral hygiene, when multiple consecutively missing teeth are replaced by internal connection type implant.

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.2
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• pp.34-43
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• 2018

Silicon has become of increasing importance as the basic element of many high-technology products. Its synthesis is very difficult requiring high temperature solid-state reactions (> $1000^{\circ}C$) or lower temperature methods ($100-200^{\circ}C$) involving hydrothermal and solvothermal reactions under extreme pH conditions. In nature, on the other hand, a wide range of living organisms have collectively evolved the means of biosilicification at the astounding rate of gigatons/year. This is impressive because biosilicification in these organisms occurs under mild physiological conditions. Marine sponges possess the ability to sequester soluble silicon sources from their environments and assemble them into intricate 3D architecture. The advent of molecular biology has recently made it possible to glean molecular information about biosilicification from these systems and it turned out that enzyme silicatein is the core of biosilicification. In this review, biosilicification regulated by silicatein and its mechanism are described. Also, production of silicatein through recombinant technology and several applications of recombinant silicatein are described including immobilization of silicatein, formation of Au or Ag nanoparticles on nanowires, nanolithography approaches, core-shell materials, encapsulation, bone replacement materials, and microstructured optical fibers.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.3
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• pp.33-43
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• 2013

Objectives: Osteoporosis is characterized by bone loss and morbidity with osteoporotic fracture. In this study, the author aimed to evaluate the effect of dried roots of Rehmannia glutinosa extract (RGE) on osteoblast proliferation in murine calvarial cells. Methods: The osteoblast separated from murine calvariae was cultivated for 6 days and evaluated the cell function. After the addition of RGE on the culture medium, we determined the effect of RGE on the cell viability, cell proliferation, protein synthesis, alkaline phosphatase activity, collagen synthesis and calcified nodule formation of the cultivated osteoblast. Results: The results were summarized as follows. 1. RGE did not change the survival rate of rat calvarial osteoblast. 2. RGE increased the proliferation of rat calvarial osteoblast. 3. RGE increased ALP activity of rat calvarial osteoblast., 4. RGE slightly affected protein synthesis of rat calvarial osteoblast. 5. RGE increased collagen synthesis of rat calvarial osteoblast. 6. RGE slightly affected calcified nodule formation of rat calvarial osteoblast. Conclusions: From these results, it is concluded that RG might improve the osteoporosis resulted from augmentation of osteoblast proliferation.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.222-228
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• 2010

The purpose of this study was to compare mineral trioxide aggregate (MTA; Dentsply, Tulsa Dental, Tulsa, OK, USA), which is widely used as root-end filling material, with DiaRoot BioAggregate (DB; Innovative BioCaramix Inc, Vancouver, BC, Canada), newly developed product, by using MG63 osteoblast-like cells. MTA, DB, and Intermediate Restorative Material (IRM; Dentsply Caulk, Milford, DE, USA) were used for root-end filling material while tissue culture plastic was used for control group. Each material was mixed and, the mixtures were left to set for 24 hours. MG63 cells were seeded to each group and then they were cultured for attachment for 4 hours. Following the attachment of cells to the root-end filling material, early cellular response was observed. After another 12 hours'culture, the level of attachment between cells and material was observed and in order to identify the effect of each material to bone formation, transforming growth factor beta1 ($TGF{\beta}1$) and osteocalin (OC) were estimated by using enzyme-linked immunosorbent assay (ELISA), and the amount of alkaline phosphatase (ALP) was also measured. The data were analyzed using one-way ANOVA. As a result, only at OC and the number of cells which were attached to materials, there was no statistical difference between MTA and DB. At other items, there was statistically significant difference in all groups. Although DB has not shown exactly the same cellular response like that of MTA, the number of attached cells shows that biocompatibility of the material and OC indicates bone formation rate. Therefore, if DB is used for root end filling material, it is expected to lead to similar results to MTA.