• Polymer(Korea)
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• v.27 no.3
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• pp.242-248
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• 2003

PP-g-(AN/Sty) was synthesized by grafting with acrylonitrile (AN) and styrene (Sty) onto PP staple fiber using an electron beam accelerator and followed by amidoximination and phosphorylation. Mole fraction of AN in the graft chain increased with the increase of the AN content in the monomer mixture. The highest AN grafting yield of 45% was obtained at a monomer ratio of 40 vol% AN/60 vol% Sty. Mole fraction of AN in the graft chain decreased with the increase of methanol amount used its solvent. As reaction temperature increased, the grafting yield of copolymer increased and reached equilibrium at 50$^{\circ}C$. Amount of amidoxime group in fibrous ion exchanger was increased as increasing amount of hydroxylamine, and the maximum content of amidoxime group was observed at 5.8 mmol/g with the 9 wt% hydroxylamine concentration. Content of phosphorous group in fibrous ion exchanger increased up to 0.5 N phosphoric acid concentration, and then leveled off. The adsorption ability of the copolymer for uranyl ion by the chelating adsorbents was in the following order : bifunctional PP-g-(AN/sty) > amidoximated PP-g-(AN/Sty) > phosphorylated PP-g-(AN/Sty).

• Journal of Korean Neurosurgical Society
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• v.30 no.12
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• pp.1388-1393
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• 2001

Objective : In the retrospective analyzing 19 consecutive patients with subaxial cervical spine(C3~T1) injury treated by posterior cervical fixation and fusion, clinical manifestation, radiologic finding, operative technique, and postoperative results following 6 months were analyzed. Materials and Methods : Most common fracture level was C4-5, mean age 41, and male to female ratio 13 : 6. The most common cause of injury was motor vehicle accident(17 cases). In 19 cervical procedures, interspinous triple wiring was done in 14 cases, lateral mass plating in 5 cases, and additional anterior fusion in 2 cases. Results : Twelve weeks after operation, all cases were reviewed by plain cervical radiogram. In 17 cases that treated by posterior fusion only, 14 cases(81%) had kyphotic angle change less than $5^{\circ}$, 2 cases(12%) $5-20^{\circ}$, and 1 case(6%) more than $20^{\circ}$. Overall fusion rate was 88%, and there was no significant difference of bone fusion rate between autogenous bone graft and allogenous bone graft. Conclusion : In the case of severe posterior column injury or displacement, posterior approach seems superior to anterior approach, but in the case of combined anterior column injury, anterior approach is considered necessary. In this study, posterior fixation and fusion might be acceptable procedure for subaxial cervical fracture and dislocation, owing to its high fusion rate, low kyphotic angulation and low operation related complication rate.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.135-135
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• 2001

Purpose： To know the differences of the proton MR spectroscopic features of the liver between th patients with graft-versus-host disease (GVHD) and without GVHD (non-GVHD) after to marrow transplantation (BMT), and to evaluate the possibility to discriminate GVHD fro non-GVHD by analysis of the in vivo proton MR spectra. Method： We evaluated the in vivo proton MR spectra from the livers of 37 patients wh underwent BMT. Our series included 14 cases with GVHD and 23 without GVHD in the liver. Nineteen men and 18 women were included in our series. All cases of GVHD and 2 o non-GVHD were confirmed by liver biopsy and remaining of non-GVHD by evaluation clinical follow up. Proton MR spectroscopy (1H-MRS) was performed at 1.5T GE Sign Horizon (GE Medical System, Milwaukee, USA) system using localized proton STEAM sequence and body coil in all cases with subjects were located in supine position. N respiratory interruption was required during the spectroscopic signal acquisition. Paramete using in MRS were： TR = over 3000ms, TE = 30ms, number of scans = 128, voxel size = ($2{\times}2{\times}2$)$cm^3$, and one NEX. We evaluated the spectra with an attention to the differences o patterns of the peaks between GVHD and non-GVHD groups. The ratio of peak area of peaks at 1.6-4.1ppm to lipid (0.9-1.6ppm) [P(1.6-4.1ppm)/P(0.9-1.6ppm)] was calculated in GVHD and non-GVHD group, and compared the results between these groups. We als evaluated the sensitivity and specificity for discriminating GVHD from non-GVHD by anal of 1H-MRS.

• Journal of Chest Surgery
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• v.24 no.12
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• pp.1173-1184
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• 1991

This report is a review of 55 cases of peripheral arterial disease, who were treated at the department of thoracic and cardiovascular surgery, Masan Koryo General Hospital from January, 1986 to December, 1990. The result are summerized as follows ; 1. The incidence of peripheral arterial disease were as follows that : Arterial injury was in 21 cases(38.2%), arteriosclerosis oblitrans 18cases(32.7%), thromboembolism 9cases(16.4%), Buerger's disease was in 7cases(12.7%). 2. Overall male to female ratio was 6.8 : 1, the prevalent age was 3rd and 4th decade in arterial injury, 7th and 8th decade in atherosclerosis and thromboembolism and 5th and 6th decade in Buerger's disease. 3. The farmer was the first ranked occupation of these patients with chronic occlusive arterial disease, which was composed of 17 cases (68%). 4. 23 cases of patients with chronic occlusive disease has been smoking and most of them have been smoking over 10 years. 5. The clinical symptoms in acute and chronic arterial obstruction were pain, claudication, gangrene and coldness in order. 6. The duration of symptom of chronic arterial occlusive disease was less 1 years in 15 cases(60%). 7. The lower extremity were more affected than upper extremity in peripheral arterial disease. 8. The cause of arterial injury was traffic accident 9 cases(42.9%) stab wound 8 cases (38.1%), postangiography 2 cases(9.5%) and belt injury 1 case. 9. The etiologic factors of acute arterial occlusion was arterial fibrillation myocardial ischemia and postangiography in order. 10. Lumber sympathectomy in Buerger's disease, artificial bypass graft in atherosclerosis and thromboembolctomy in thromboembolism, end to end with vein graft in arterial injury were performed frequently. 11. Conclusively overall result was satis factory but 3 cases was below knee amputated after operation of chronic arterial occlusive disease.

• Elastomers and Composites
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• v.53 no.3
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• pp.175-180
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• 2018

Solution-styrene-butadiene rubber (SSBR) composites were manufactured using four kinds of fillers: silica-silane coated carbon black (SC-CB) hybrid, starch-SC-CB hybrid, pure silica, and pure starch. The influence of filler type on the mechanical properties of the rubber matrix was studied in this work. SC-CB was prepared by silane-graft-coating using vinyl triethoxy silane and carbon black, which enhanced the dispersion effect between the rubber matrix and the filler, and improved the mechanical properties of the compounds. The morphology of the composites was observed by field-emission scanning electron microscopy (FE-SEM). The thermal decomposition behavior of the composites was determined by thermogravimetric analysis (TGA), and the crosslinking behavior of the composites was tested using a rubber process analyzer (RPA). The hardness, tensile strength, swelling ratio, and gas transmittance rate of the composites were evaluated according to ASTM. The test results revealed that with the addition of SC-CB, the hybrid fillers, especially those blended with silica, showed a better reinforcement effect, the highest hardness and tensile strength, and stable thermal decomposition behavior. This implies that the silica-SC-CB hybrid filler has a notable mechanical reinforcement effect on the SSBR matrix. Because of self-crosslinking during its synthesis, the starch-SC-CB hybrid filler produced the most dense matrix, which improved the anti-gas transmittance property. The composites with the hybrid fillers had better anti-swelling properties as compared to the neat SSBR composite, which was due to the hydrophilicity of silica and starch.

• Polymer(Korea)
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• v.37 no.4
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• pp.539-546
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• 2013

Amino group-terminated poly(N-isopropylacrylamide) (PNIPAAm-$NH_2$) was synthesized via a radical polymerization of N-isopropylacrylamide (NIPAAm) using 2-aminoethanethiol hydrochloride (AESH) as a chain transfer agent. The molecular weight of the PNIPAAm-$NH_2$ was controlled by changing the concentration of AESH. The LCST of the aqueous solution of PNIPAAm-$NH_2$ increased slightly with increasing the AESH concentration. Alginate-g-PNIPAAm copolymer was synthesized by grafting PNIPAAm-$NH_2$ onto sodium alginate using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide and N-hydroxysuccinimide. The formation of the grafted copolymers was confirmed by FTIR spectroscopy, solubility in water, and SEM-EDS. Alginate-g-PNIPAAm also exhibited swelling-deswelling behavior. However, it showed a LCST at a slightly increased temperature compared to PNIPAAm. The swelling ratio of the alginate-g-PNIPAAm hydrogel increased with the increase of the grafted PNIPAAm content.

• Journal of Adhesion and Interface
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• v.12 no.2
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• pp.62-66
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• 2011

In this study, we synthesized a excellent adhesive chlorinated polyolefin (CPO)-g-$\beta$-carboxy ethyl acid ($\beta$-CEA) by radical polymerization. Also, we prepared low-level toxic primer for polypropylene (PP) using CPO-g-$\beta$-CEA and studied toxic and adhesion property. We identified the graft structure and properties of the prepared chlorinated polyolefin-g-$\beta$ CEA using FT-IR, DSC, UTM. Graft ratio were optimum value at 5 wt% $\beta$-CEA contents in CPO-g-$\beta$ CEA. And the primer for PP was prepared with CPO-g-$\beta$ CEA and adhesive builder PX-95 content. Finally, optimum peel strength obtained when PX-95 contents was 3 wt%.

• Journal of Korean Neurosurgical Society
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• v.41 no.5
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• pp.301-305
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• 2007

Objective : The postoperative subsidence of anterior cervical interbody fusion for cervical degenerative diseases gives rise to segmental kyphotic collapse, screw loosening, and chronic neck pain. So, intraoperative custom-made polymethylmethacrylate [PMMA] C-cage has been developed to prevent subsidence following anterior cervical fusion. Methods : A total of patients who underwent anterior cervical interbody fusion with a intraoperative custom - made cervical cage filled with local bone and demineralized bone matrix [group A] were analyzed prospectively from June 2004 to June 2005. These were compared with 40 patients who were treated with iliac bone graft [group B]. We evaluated subsidence ratio, change of segmental angle, distraction length and segmental angle. Statistical analysis was performed using independent sample t-test and Pearson correlation coefficient. Results : Group A had a statistically significant decrease in subsidence ratio [$0.64{\pm}0.43%$, p=0.00]. distraction length [$2.42{\pm}1.25\;mm$, p=0.02], and follow angle change [$1.78{\pm}1.69^{\circ}$, p=0.01] as compared with Group B. However, there was no statistically significant difference in postoperative segmental angle change [p=0.66]. On the analysis of the correlation coefficient, the parameters showed no interrelationships in the group A. On the other hand, subsidence ratio was affected by distraction length in the group B [Pearson correlation=0.448]. Conclusion : This operative technique would be contributed for the reduction of a postoperative subsidence after the anterior cervical interbody fusion procedure for cervical disc disease with moderate to severe osteoporotic condition and segmental loss of lordosis.

• Journal of Chest Surgery
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• v.28 no.11
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• pp.983-988
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• 1995

From January 1983 to December 1994, 48 cyanotic patients were underwent a subclavian artery-pulmonary artery shunt using polytetrafluoroethylene[PTFE for the purpose of improvement of reduced pulmonary blood flow. The diameters of the PTFE used were 4mm[4 cases , 5mm[36 cases , and 6mm[8 cases sizes. The effectiveness of modified Blalock-Taussig shunts was evaluated clinically and angiographically. There were 5 early deaths and 2 late deaths. There were 3 early shunt failures and 5 late shunt failures. The overall graft patency rate was 83.3%. Postoperative hemoglobin was reduced significantly[p = 0.0011 in comparison of the preoperative and postoperative hemoglobin, SaO2, PaO2, and cardiothoracic ratio.

• Interaction and multiscale mechanics
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• v.4 no.2
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• pp.107-122
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• 2011

Mechanical behavior in nano-sized structures differs from those in macro sized structures due to surface effect. As the ratio of surface to volume increases, surface effect is not negligible and causes size-dependent mechanical behavior. In order to identify this size effect, atomistic simulations are required; however, it has many limitations because too much computational resource and time are needed. To overcome the restrictions of the atomistic simulations and graft the well-established continuum theories, the continuum model considering surface effect, which is based on the bridging technique between atomistic and continuum simulations, is introduced. Because it reflects the size effect, it is possible to carry out a variety of analysis which is intractable in the atomistic simulations. As a part of the application examples, the homogenization method is applied to micro/nano thin films with porosity and the homogenized elastic coefficients of the nano scale thickness porous films are computed in this paper.