• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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• pp.7-13
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• 2009

Purpose: The purpose of this study was to evaluate the effect of Sodium hyaluronate-Sodium carboxymethyl cellulose (HA-CMC) on tissue adhesion after tenorrhapy in tenotomized Achilles tendon of the Sprague-Dawley rat. Materials and Methods: Twenty-eight legs of 14 Sprague-Dawley rat were used in study. After tenotomy of the Achilles tendons, tenorrhaphies were performed. Simple tenorrhaphy without any other procedures were performed on the left Achilles tendons (control group), and additional HA-CMC injections were done prior to the tenorrhaphy on the right Achilles tendons (HA-CMC group). Gross and histological examinations were made to identify differences between the two groups, 1, 2, 6, 8, 10, 12 and 14 weeks respectively. Results: Distinct decrease in granulation tissues and adhesions were seen in the HA-CMC group during gross inspection at 6 and 8 week after the operation. On histological analysis of the HA-CMC group, although increased infiltrations of inflammation cells were observed during 1 week, less adhesion were seen at 6, 8 and 10 weeks after the operation. In HA-CMC group, superior healing processes were seen at 6, 8 and 10 weeks and less fibrotic changes, compared to control group, were seen at 2 and 6 weeks. Conclusion: Prevention of adjacent tissue adhesion was made possible through decrease in collagen deposition and fibrosis by injecting HA-CMC before tenorrhaphy of Achilles tendon. Also, histologically faster healing process of the collagen fibers within the Achilles tendon was observed.

• Progress in Superconductivity
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• v.8 no.1
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• pp.98-103
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• 2006

[$Bi_2Sr_2Ca_1Cu_2O_x$](BSCCO 2212) tubes were fabricated by centrifugal melting process(CMP). BSCCO 2212 powder was melted in a Pt crucible and solidified in a rotating steel mold. The BSCCO 2212 tube samples separated from steel mold were heat-treated at $800^{\circ}C\;and\;810^{\circ}C$ in oxygen flow. The critical current($I_c$) of the samples was measured by transport measurement at 77K, and the microstructure was investigated by scanning electron microscope. The $J_c$ at 77K of the tubes heated treated at $800^{\circ}C\;and\;810^{\circ}C$ were 197 and 240 $A/cm^2$, respectively. It was observed that the plate like grains in BSCCO 2212 tube was more developed in the sample heat treated at $810^{\circ}C\;and\;800^{\circ}C$ heated tube. It is found that the critical current($I_c$) of the BSCCO 2212 sample was dependent on the heating schedule regarding the growth of the BSCCO 2212 grains.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.1
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• pp.30-40
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• 2004

Purpose : The purpose of this study was aimed to compare the shear bond strength on dentin of three dentin bonding agents and two resin cements used in conjunction with self-cured composite resin core material. Material and method : Control group and six experimental groups were divided for this study. Control group was designated as specimens bonded with Tenure$ A&B^{(R)}$. Experimental groups were as follows : PB-BL group : specimens bonded with Prime&Bond $NT^{(R)}$, $BondLink^{(R)}$ SB-BL group : specimens bonded with $^{(R)}$, BondLink$SingleBond^{(R)}$ PB group : specimens bonded with Prime&Bond $NT^{(R)}$ SB group : specimens bonded with $SingleBond^{(R)}$ PF group : specimens bonded with $Panavia-F^{(R)}$ BI group specimens bonded with Bistite $II^{(R)}$ All specimens were stored in $37^{\circ}C$ distilled water for 24 hours, followed by the shear bond strength was tested by universal testing machine. The data was analysed statistically by Mann-Whitney test. Results : 1. For Prime&Bond $NT^{(R)}$ and $SingleBonde^{(R)}$, the shear bond strength was 0.24 MPa and 7.19 MPa each by each, while Tenure $A&B^{(R)}$ group control was measured at 13.93 MPa (p<0.05). Especially for Prime&Bond $NT^{(R)}$ it did not get conjunction with dentin. 2. For Prime&Bond $NT^{(R)}$ and $SingleBond^{(R)}$ using $BondLink^{(R)}$, there was no significant difference as a result of 11.73 MPa and 14.00 MPa each by each (p<0.05). 3. For $Panavia-F^{(R)}$ and Bistite $II^{(R)}$, they showed the highest shear bond strength as measured by 18.24 MPa and 16.09 MPa each (p<0.05).

• Journal of the Korean Solar Energy Society
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• v.28 no.1
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• pp.9-17
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• 2008

An experimental investigation has been carried out to study the effects of different working fluids on the behavior and thermal performance of a hi-directional thermodiode. The thermodiode was made up of two rectangular loops mounted between a collector plate and a radiator plate. Rotatable joints between the horizontal and inclined segments of the loops enable easy alteration of the direction of heat transfer. The loops and the tank were filled with a working fluid for effective heat transfer when the thermodiode was forwarded biased. Six different working fluids were tested with thermal conductivity values ranging from 0.1 to $0.56W/m-^{\circ}C$, thermal expansion coefficient values ranging from $1.8\;{\times}10^{-4}$ to $1.3\;{\times}\;10^{-3}\;K^{-1}$, and kinematic viscosity values ranging from $0.65\;{\times}\;10^{-6}$ to $100\;{\times}\;10^{-6}\;m^2/s$. Especially, mixtures of $Al_2O_3$ (30nm Particle) in deionized water have been tested for the volumetric ratios of 0.01, 0.02, 0.03, 0.1, 0.2%. Each experiment was carried out after the loop was filled with a working fluid for effective heat transfer and the thermodiode was forwarded biased. The solar thermodiode was heated by a radiant heater consisting of 20 halogen lamps that generated a heat flux of about $1000\;W/m^2$ on the collector surface. Results are given in terms of temperature development in different parts of the loop as heat is delivered from its hot end to the surrounding atmosphere by the radiator made of copper plates.

• Korean Journal of Materials Research
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• v.18 no.5
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• pp.283-288
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• 2008

The effect of sintering aids and glass-frit on the densification and resistivity of silver paste was investigated in an effort to enhance the sintered density and electrical conductivity of the silver electrode. To prepare Pb-free silver paste for use at low sintering temperatures, two commercial silver powders ($0.8\;{\mu}m$ and $1.6\;{\mu}m$ in size) and 5wt.% lab-synthesized nanoparticles (30-50 nm in size) as a sintering aids were mixed with 3 wt.% or 6 wt.% of glass frit ($Bi_2O_3$-based) using a solvent and three roll mills. Thick films from the silver paste were prepared by means of screen printing on an alumina substrate followed by sintering at $450^{\circ}C$ to $550^{\circ}C$ for 15 min. Silver thick films from the paste with bimodal particles showed a high packing density, high densification during sintering and low resistivity compared to films created using monomodal particles. Silver nanoparticles as a sintering aid enhanced the densification of commercial silver powder at a low sintering temperature and induced low resistivity in the silver thick film. The glass frit also enhanced the densification of the films through liquid phase sintering; however, the optimum content of glass frit is necessary to ensure that a dense microstructure and low resistivity are obtained, as excessive glass-frit can provoke low conductivity due to the interconnection of the glass phase with the high resistivity between the silver particles.

• Journal of Korean Foot and Ankle Society
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• v.16 no.4
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• pp.223-228
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• 2012

Purpose: To treat hallux valgus in old age patients with chevron metatarsal osteotomy and to see the subsequent clinical and radiological outcomes. Materials and Methods: 23 cases of 18 hallux valgus patients of age 60 years or older who received proximal or distal corrective osteotomy from April 2007 to August 2009 and were followed up for at least 1 year were included in the study. The mean age at operation was 65 years (range, 60~81 years), and the mean follow-up period was 2 years and 6 months (range, 1 year~3 years 6 months). Clinical outcome was assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) score, complications, satisfaction rate, as well as measurements and comparison of pre- and postoperative hallux valgus angles, the 1st~2nd intermetatarsal angle, and the position of hallucal medial sesamoid bone. Results: The AOFAS score was improved from preoperative average of 35.1 (range, 13-47) to average 85.1 at last follow-up (range, 75-100). Patients were satisfied about the operation in 21 cases (91.3%). Preoperative hallux valgus angle was $31.7^{\circ}$ on average (range, $19.1^{\circ}-48.9^{\circ}$), and $4.9^{\circ}$ on average at last follow-up (range, $0.3^{\circ}-21.2^{\circ}$). The 1st~2nd intermetatarsal angle was $14.4^{\circ}$on average (range, $8.7^{\circ}-25.7^{\circ}$) and $3.1^{\circ}$ on average at last follow-up (range, $0.6^{\circ}-7.5^{\circ}$). The hallucal medial sesamoid bone position was improved from preoperative average 3.5 (range, 3-4) to postoperative average 1.0 (range, 0-2). Conclusion: Proximal and distal metatarsal osteotomy treatment yielded good clinical and radiological outcomes in old age hallux valgus patients.

• Carbon letters
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• v.21
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• pp.33-50
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• 2017

In this study, Fe-Ni bimetallic catalyst supported on kaolin is prepared by a wet impregnation method. The effects of mass of kaolin support, pre-calcination time, pre-calcination temperature and stirring speed on catalyst yields are examined. Then, the optimal supported Fe-Ni catalyst is utilised to produce multi-walled carbon nanotubes (MWCNTs) using catalytic chemical vapour deposition (CCVD) method. The catalysts and MWCNTs prepared using the optimal conditions are characterized using high resolution transmission electron microscope (HRTEM), high-resolution scanning electron microscope (HRSEM), electron diffraction spectrometer (EDS), selected area electron diffraction (SAED), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and X-ray diffraction (XRD). The XRD/EDS patterns of the prepared catalyst confirm the formation of a purely crystalline ternary oxide ($NiFe_2O_4$). The statistical analysis of the variance demonstrates that the combined effects of the reaction temperature and acetylene flow rate predominantly influenced the MWCNT yield. The $N_2$ adsorption (BET) and TGA analyses reveal high surface areas and thermally stable MWCNTs. The HRTEM/HRSEM micrographs confirm the formation of tangled MWCNTs with a particle size of less than 62 nm. The XRD patterns of the MWCNTs reveal the formation of a typical graphitized carbon. This study establishes the production of MWCNTs from a bi-metallic catalyst supported on kaolin.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.47-53
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• 1996

We examined the expression of the heat shock proteins (HSPs) and glucose-regulated proteins (GRPs) during phorbol 1 2-myristate 1 3-acetate (PMA)-induced megakaryocytic differentiation of human er"'throleukemia K562 cells. PMA-treated K562 cells showed a cell growth arrest and alteration in morphology and patterns of gpllIa and c-myc expression, characteristic of megakaryocytic differentiation. During the megakaryocytic differentiation, HSP9OA, HSP9OB, and HSP28 mRNA and protein levels markedly decreased, while GRP78/B and GRP94 mRNA levels were enhanced. On the other hand, HSP7OA and HSP7OB mRNA levels were reduced, but HSP7O protein levels were not changed by PMA treatment. These results suggest specific roles for the HSPs and GRPs in K562 cell proliferation and megakaryocic differentiation.tion.

• Journal of Magnetics
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• v.20 no.2
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• pp.103-109
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• 2015

In this study, the authors attempted to produce a medical radiation shielding fiber that can be produced at a nanosize scale and that is, unlike lead, harmless to the human body. The performance of the proposed medical radiation shielding fiber was then evaluated. First, diamagnetic bismuth oxide, an element which, among elements that have a high atomic number and density, is harmless to the human body, was selected as the shielding material. Next, 10-100 nm sized nanoparticles in powder form were prepared by ball milling the bismuth oxide ($Bi_2O_3$), the average particle size of which is $1-500{\mu}m$, for approximately 10 minutes. The manufactured bismuth oxide was formed into a colloidal solution, and the radiation shielding fabric was fabricated by curing after coating the solution on one side or both sides of the fabric. The thicknesses of the shielding sheets prepared with bismuth oxide were 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 1.0 mm. An experimental method was used to measure the absorbed dose and irradiation dose by using the lead equivalent test method of X-ray protection goods presented by Korean Industrial Standards; the resultant shielding rate was then calculated. From the results of this study, the X-ray shielding effect of the shielding sheet with 0.1 mm thickness was about 55.37% against 50 keV X-ray, and the X-ray shielding effect in the case of 1.0 mm thickness showed shielding characteristics of about 99.36% against 50 keV X-ray. In conclusion, it is considered that nanosized-bismuth radiation shielding fiber developed in this research will contribute to reducing the effects of primary X-ray and secondary X-ray such as when using a scattering beam at a low level exposure.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.299-310
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• 2007

It will be necessary to make proper management plans to preserve the air quality in good level for the public. In order to make these plans, source information and detail emission inventories of the city and near industrial areas should be given. However, lack of the source measurements data makes us more difficult to complete the source inventory. VOC source Inventory could be utilized for the feasibility study to estimate the contribution of VOC sources presenting to the receptor such as residential area. It may give policy maker an idea how to control the air quality, and improve their social environment in the area. This study shows data that measured VOCs concentrations from the local industrial areas in Jeonju during from May 2005 to January 2006. The samples were collected from the near sources in 7 major factories in the industrial park as well as 5 general sources in near city Jeonju area to elucidate the abundances of speciated VOCs and their spacial and temporal distributions depending on source bases. Industrial sources are as follows; chemical, food, paper, wood, metal, non-metal (glass), and painting (coating) industries. The 5 general sources are sampled from tunnel, gasoline gas station, dry cleaning shop, printing (copy) shop, and road pavement working place in urban area. To understand the near source effect at receptor, samples from the 2 receptor sites (one is at center of the industrial complex and the other site is at distance residential area downwind from the center) were collected and analyzed for the comparison to source concentration. The mass contributions of the speciated VOC to total mass of VOCs measured from the different sources and ambient (2 receptors) were presented and discussed.