• Archives of Reconstructive Microsurgery
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• v.9 no.2
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• pp.139-146
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• 2000

The aim of this study was to assess whether the functional regeneration of a lyophilized autografted cartilage could be improved by implanting a vascularized muscle flap into the medullary canal of autografted proximal humerus. A hemijoint reconstruction using a lyophilized osteochondral autograft in proximal humerus was done in 4 rabbits for control, and combined with an vascularized intramedullary muscle flap in another 4 rabbits for the experimental group. Graft healing and the repair process of osteochondral graft were followed by serial radiographs and histologic changes for 9 weeks after experiments. Each two rabbits in control and in experimental group on 5th and 9th week after implantation of hemijoint were sacrified. The results were as follows: 1. All of control and experimental froups on 5th week united solidly on osteotomized site radiologically, but their articular cartilages were destroyed more seriously in the control than that in experimental group with muscle flap on 5th and 9th week after experiment... 2. Histochemically, the cartilage surface are completely destroyed and revealed with severe osteoarthritic changes on all cartilage layers in control, but cartilaginous erosions are mild to moderate and their arthritic changes are also mild with somewhat regeneration of chondrocytes on deep layers more prominetly on 9th week of the experimental group. 3. The amount of collagen and protenized matrix which was determined by Masson-Trichrome stain was markedly decreased that means the weakness of bony strength and low osteogenic potential in lyophilized cartilage. These results suggest that an intramedullary vascularized muscle flap can improve the functional results of lyophilized osteochondral autograft by providing both increased vascularity and populations of mesenchymal cells to initiate new bone formation on osteotomized site as well as the regeneration of deep layers in articular cartilage. In clinical relevances, this lyophilized hemijoint autograft combined with an intramedullary vascularized muscle pedicle graft might be used very effectively for the treatment of malignant long bone tumors to preserve the joint functions, all or partly, and so to replace it with the artificial joint after tumor excision and hemijoint autograft.

• Polymer(Korea)
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• v.30 no.1
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• pp.14-21
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• 2006

Tissue engineering techniques require the use of a porous biodegradable/bioresorbable scaffold, which server as a three-dimensional template for initial cell attachment and subsequent tissue formation in both in vitro and in vivo. Small intestinal submucosa (SIS) has been investigated as a source of collagenous tissue with the potential to be used as biomaterials because of its inherent strength and biocompatibility. SIS-loaded poly(L-lactide-co-glicolide)(PLGA) scaffolds were prepared by solvent casting/particle leaching. Characterizations of SIS/PLGA scaffold were carried out by SEM, mercury porosimeter, and so on. Muscle-derived stem cells can be differentiated in culture into osteoblasts, chondrocytes, and even myoblasts by the controlling the culture environment. Cellular viability and proliferation were assayed by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide(MTT) test. Osteogenic differential cells were analyzed by alkaline phosphatase(ALP) activity. SIS/PLGA scaffolds were implanted into the back of athymic nude mouse to observe the effect of SIS on the osteoinduction compared with controlled PLGA scaffolds. Thin sections were cut from paraffin embedded tissues and histological sections were conducted hematoxylin and eosin (H&E), Trichrome, and von Kossa. We observed that bone formatioin of SIS/PLGA hybrid scaffold as natural/synthetic scaffold was better thean that of only PLGA scaffold. It canb be explained that SIS contains various kinds of bioactive molecules for osteoinduction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.371-377
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• 2014

In tissue engineering, a scaffold is a three-dimensional(3D) structure that serves as a template for regeneration the functions of damaged tissues or organs. Among materials for scaffolds, polycaprolactone(PCL) and ${\beta}$-tricalcium phosphate(${\beta}$-TCP) are biodegradable and biocompatible. In this study, we fabricated 3D PCL, blended PCL (60 wt %)/${\beta}$-TCP (40 wt %), and pure ${\beta}$-TCP scaffolds by a multi-head scaffold fabrication system. Scaffolds with a pore size of $600{\pm}20{\mu}m$ was observed by scanning electron microscopy. The effects of 3D PCL, blended PCL (60 wt %)/${\beta}$-TCP (40 wt %) and pure ${\beta}$-TCP scaffolds were analyzed by evaluating their mechanical characteristics. In addition, in an in-vitro study using osteoblast-like saos-2 cells, we confirmed the effects of 3D scaffolds on cellular behaviors such as cell adhesion and proliferation. In summary, the 3D blended PCL (60 wt %)/${\beta}$-TCP (40 wt %) scaffold was found to be suitable for human cancellous bone in terms of its the compressive strength, biocompatibility, and osteoconductivity. Thus, blending PCL and ${\beta}$-TCP could be a promising approach for fabricating 3D scaffolds for effective bone regeneration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1195-1201
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• 2005

This study has investigated the bioavailability of calcium in eggshell powder (ESP) fortified ramen. Wean-ling SD rats were maintained for 2 weeks on 0.05$\%$ low calcium diet then assigned randomly to one of 5 groups. Animals were provided for 4 weeks one of 3 different experimental diets containing 0.15$\%$ calcium as $CaCo_{3}$, NFDM, or ESP fortified ramen. Two control groups were fed either 0.05$\%$ calcium or general ramen containing 0.08$\%$ calcium. The body weight, diet intake, food efficiency ratio (FER), bone growth, calcium contents of bones, and apparent absorption were measured. Experimental results show that regardless of calcium sources 0.15$\%$ calcium groups increased body weight, weight and length, calcium content, and the strength of two bones (tibia and femur) significantly compared to 0.05$\%$ calcium group. The apparent absorption rate of calcium also showed similar results supporting the bioavailability of ESP fortified ramen is not inferior to either NFDM or $CaCO_{3}cdot$ The results indicate that ESP fortified ramen is a proper mediate for calcium fortification in Korea.

• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.339-346
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• 2011

The effects of mineral admixtures on the bonding properties of cement mortar to polyolefin based synthetic fiber were evaluated. The mineral admixtures consisted of 0%, 5%, 10%, and 15% fly ash, blast furnace slag, and metakaolin in cement. Bond interactions between the cement mortar and the polyolefin based synthetic fiber were determined by Dog-bone bond tests. Bond tests of the polyolefin based synthetic fiber showed an increase in pullout load with the strength of the cement mortar. Also, the interface toughness of polyolefin based synthetic fiber in cement mortar increased as the fly ash, blast furnace slag, and metakaolin contents increased. The microstructure of polyolefin based synthetic fiber surface was examined after the pullout test to analyze the frictional resistant force according to the replacement ratio of fly ash, blast furnace slag, and metakaolin during the pullout process of polyolefin based synthetic fiber in cement mortar. The scratched of polyolefin based synthetic fibers increased with the replacement ratio of fly ash, blast furnace slag, and metakaolin. Also, the interface toughness was enhanced by adhesion forces induced by the fly ash, blast furnace slag, and metakaolin.

• Tissue Engineering and Regenerative Medicine
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• v.15 no.6
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• pp.735-750
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• 2018

BACKGROUND: The major challenge of tissue engineering is to develop constructions with suitable properties which would mimic the natural extracellular matrix to induce the proliferation and differentiation of cells. Poly(${\varepsilon}$-caprolactone)-poly(ethylene glycol)-poly(${\varepsilon}$-caprolactone) (PCL-PEG-PCL, PCEC), chitosan (CS), nano-silica ($n-SiO_2$) and nano-hydroxyapatite (n-HA) are biomaterials successfully applied for the preparation of 3D structures appropriate for tissue engineering. METHODS: We evaluated the effect of n-HA and $n-SiO_2$ incorporated PCEC-CS nanofibers on physical properties and osteogenic differentiation of human dental pulp stem cells (hDPSCs). Fourier transform infrared spectroscopy, field emission scanning electron microscope, transmission electron microscope, thermogravimetric analysis, contact angle and mechanical test were applied to evaluate the physicochemical properties of nanofibers. Cell adhesion and proliferation of hDPSCs and their osteoblastic differentiation on nanofibers were assessed using MTT assay, DAPI staining, alizarin red S staining, and QRT-PCR assay. RESULTS: All the samples demonstrated bead-less morphologies with an average diameter in the range of 190-260 nm. The mechanical test studies showed that scaffolds incorporated with n-HA had a higher tensile strength than ones incorporated with $n-SiO_2$. While the hydrophilicity of $n-SiO_2$ incorporated PCEC-CS nanofibers was higher than that of samples enriched with n-HA. Cell adhesion and proliferation studies showed that n-HA incorporated nanofibers were slightly superior to $n-SiO_2$ incorporated ones. Alizarin red S staining and QRT-PCR analysis confirmed the osteogenic differentiation of hDPSCs on PCEC-CS nanofibers incorporated with n-HA and $n-SiO_2$. CONCLUSION: Compared to other groups, PCEC-CS nanofibers incorporated with 15 wt% n-HA were able to support more cell adhesion and differentiation, thus are better candidates for bone tissue engineering applications.

• Journal of Biomedical Engineering Research
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• v.43 no.5
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• pp.308-318
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• 2022

The purpose of this study is to evaluate the biomechanical properties of fractured adjacent soft tissue during closed reduction after forearm fracture using the finite element method. To accomplish this, a finite element (FE) model of the forearm including soft tissue was constructed, and the material properties reported in previous studies were implemented. Based on this, nine finite element models with different fracture types and fracture positions, which are the main parameters, were subjected to finite element analysis under the same load and boundary conditions. The load condition simulated the traction of increasing the fracture site spacing from 0.4 mm to 1.6 mm at intervals of 0.4 mm at the distal end of the radioulnar bone. Through the finite element analysis, the fracture type, fracture location, and displacement were compared and analyzed for the fracture site spacing of the fractured portion and the maximum equivalent stress of the soft tissues adjacent to the fracture(interosseous membrane, muscle, fat, and skin). The results of this study are as follows. The effect of the major parameters on the fracture site spacing of the fractured part is negligible. Also, from the displacement of 1.2 mm, the maximum equivalent stress of the interosseous membrane and muscle adjacent to the fractured bone exceeds the ultimate tensile strength of the material. In addition, it was confirmed that the maximum equivalent stresses of soft tissues(fat, skin) were different in size but similar in trend. As a result, this study was able to numerically confirm the damage to the adjacent soft tissue due to the fracture site spacing during closed reduction of forearm fracture.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.1
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• pp.28-36
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• 2003

Purpose: To determine and to compare the effects of cyclic loading on the fixation strength of different femoral fixation methods in ACL reconstruction. Materials and Methods: Biomechanical test using an Instron(R) machine (Model No.5569. Mass, U.S.A) were carried out to compare the pull out strength of six different femoral fixation techniques after a cyclic loading in 72 Yorkshire pig knees. The graft-bone complex was cyclically loaded between 30N and 150N at 50 mm/min rate for 1000 cycles and maximal tensile testing was performed. A preload of 30N was applied to the graft along the axis of the tunnel 15 minutes. ANOVA and the Duncan multiple comparison test was used for the statistical analysis. Results: The mean maximum tensile strength of femoral fixation before and after the cyclic loading test were 1003.4$\pm$145N and 601.1$\pm$154N in hamstring-LA screw(R) group, 595.5$\pm$104N and 360.7$\pm$56N in hamstring-Bioscrew(R) group, 1431.7$\pm$135N and 710.7$\pm$114N in hamstring-Semifix(R) group, 603.6$\pm$54N and 459.1$\pm$46N in hamstring-Endobutton(R) fixation group, 1067.4$\pm$145 and 601.8$\pm$134N in the BPTB-Titanium interference screw group, and 987.1$\pm$168N and 588.7$\pm$124N in the BPTB-Bioscrew(R) group. And these data illustrated that cyclic loading reduces the maximum tensile strength by 40 $\%$, 39 $\%$, 50 $\%$, 24 $\%$, 44 $\%$, 40 $\%$ respectively. Conclusions: With the results of these experiments it should be emphasized that rehabilitation exercises after anterior cruciate ligament reconstruction should be executed with precaution as the repetitive flexion and extension of the knee would compromise the maximum tensile strength of the graft tendon.

• Journal of the Korean Applied Science and Technology
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• v.39 no.1
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• pp.63-73
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• 2022

The aim of this study was to cluster according to the bone age of elementary school students in order to analyze the physique, physical fitness, and skeletal maturation of each cluter group and to provide basic data for the balanced development of elementary school students through data analysis. The subjects of this study were 2243 students aged 8 to 13 years, and the skeletal maturation were calculated by applying them to the TW3 method score conversion table after the X-ray films were taken. A total of 2 components in physique were measured using a stadiometer(Hanebio, Korea, 2021) and the Inbody 270(Biospace, Korea, 2019), and a total of 7 components in physical fitness, which included muscular strength(Hand Grip Strength), balance(Bass Stick Test), agility(Plate Tapping), power(Standing Long Jump), flexibility(Sit&Reach), muscular endurance(Sit-Up), and cardiovascular endurance(Shuttle Run) were measured as well. K-Means clustering method, cross-tabulation analysis, and one-way variable analysis(ANOVA) were conducted for data processing using the SPSS PC/Program(Version 26.0) and Bristics Studio Tool, and it was considered significant at the level of p< .05. The results of this study may be summarized as follow. First, as a result of clustering using three components of skeletal maturation: retarded, normal, and advanced, cluster 1(Retarded) showed excellence in muscular strength, balance, and agility. cluster 2(Normal) showed poor flexibility, whereas cluster 3(Advanced) showed excellence in muscular strength. Second, as a result of analyzing the differences in physique according to the clustering of elementary school students by their individual characteristics, cluster 3(Advanced) showed excellence in height, weight, and body fat percentage. Third, as a result of analyzing the differences in physical fitness according to the clustering of elementary school students by their individual characteristics, cluster 3(Advanced) showed excellence in Hand Grip Strength(Left, Right), whereas cluster 1(Retarded) showed excellence in Bass Stick Test, and cluster 3(Advanced) showed excellence in Standing Long Jump.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1299-1304
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• 2005

An experiment was conducted to study the production performance of broiler breeder females (25 to 40 weeks of age) fed either reference diet or low non-phytate phosphorus (NPP) diet with or without microbial phytase (500 FYT/kg) supplementation. A weighed (160 g/b/d) quantity of feed from each diet was offered daily to 40 replicates of one bird each housed in California type cage having individual feeders. Each cage was considered as a replicate. A continuous 16-h light per day was provided using incandescent bulbs. Body weight, egg production, egg weight, feed per egg mass, egg specific gravity, egg breaking strength, shell thickness, tibia ash and serum Ca and protein concentrations were not affected by reducing the NPP level from 0.30 to 0.18% in the broiler breeder diet. Supplementation of phytase (500 FYT/kg) enzyme to the diet containing 0.18% NPP had no added advantage on any of the above production parameters. The serum inorganic P was increased significantly (p<0.05) by either enhancing the NPP content from 0.18 to 0.30% or supplementing phytase @500 FYT/kg to the diet containing low P which were found comparable. Retention of Ca and P was positive on all the diets. P retention decreased significantly (p<0.05) with either increase in NPP content or phytase supplementation in the diet. Neither NPP nor phytase supplementation influenced bone mineralization in terms of tibia ash and strength. The hatchability was not influenced by either increasing the NPP content or supplementing the enzyme phytase. Similarly, the P concentration in the egg yolk and day old chick, day old and 14th day body weight and leg score was not altered by increasing the level of NPP or supplementing phytase enzyme. The mortality was within the normal limits in all the three dietary groups. Thus, it can be concluded that 0.18% NPP (288 mg NPP intake/b/d) in the broiler breeder' diet is adequate in sustaining the optimum performance from 25 to 40 wks of age. Enhancing the NPP content or supplementation of phytase (500 FYT/kg diet) to diet containing 0.18% NPP had no added advantage on performance.