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Growth of High Quality Ge Layer on Silica Nano-Spheres Integrated Ge/Si Template Using UHV-CVD
Shin, Keun Wook,Park, Sung Hyun,Park, Yongjo,Yoon, Euijoon The Electrochemical Society 2015 ECS journal of solid state science and technology Vol.4 No.3
<P>We have investigated the growth of high quality Ge layer on Si substrate using silica nano-spheres (NSs), which behaved as masks to directly block threading dislocations. Two-step growth after the silica NS incorporation into the surface led to a coalesced Ge layer with low threading dislocation density (TDD). TDD in the resultant Ge layer was reduced from 6.4 × 10<SUP>8</SUP> to 6.9 × 10<SUP>7</SUP> cm<SUP>−2</SUP>, and decreased further to 1.4 × 10<SUP>7</SUP> cm<SUP>−2</SUP> by post annealing. In addition to the TDD reduction, we speculated that the suppression of {111} facet during the growth restricted significantly the generation of planar defects.</P>
Kim, Dong Wook,Chung, Weon Kuu,Shin, Jungwook,Lim, Young Kyung,Shin, Dongho,Lee, Se Byeong,Yoon, Myongguen,Park, Sung-Yong,Shin, Dong Oh,Cho, Jung Keun BioMed Central 2013 Radiation oncology Vol.8 No.-
<P><B>Background</B></P><P>We measured and assessed ways to reduce the secondary neutron dose from a system for proton eye treatment.</P><P><B>Methods</B></P><P>Proton beams of 60.30 MeV were delivered through an eye-treatment snout in passive scattering mode. Allyl diglycol carbonate (CR-39) etch detectors were used to measure the neutron dose in the external field at 0.00, 1.64, and 6.00 cm depths in a water phantom. Secondary neutron doses were measured and compared between those with and without a high-hydrogen–boron-containing block. In addition, the neutron energy and vertices distribution were obtained by using a Geant4 Monte Carlo simulation.</P><P><B>Results</B></P><P>The ratio of the maximum neutron dose equivalent to the proton absorbed dose (H(10)/D) at 2.00 cm from the beam field edge was 8.79 ± 1.28 mSv/Gy. The ratio of the neutron dose equivalent to the proton absorbed dose with and without a high hydrogen-boron containing block was 0.63 ± 0.06 to 1.15 ± 0.13 mSv/Gy at 2.00 cm from the edge of the field at depths of 0.00, 1.64, and 6.00 cm.</P><P><B>Conclusions</B></P><P>We found that the out-of-field secondary neutron dose in proton eye treatment with an eye snout is relatively small, and it can be further reduced by installing a borated neutron absorbing material.</P>
신영철,박봉근,정학영,양승욱,박한성 대한슬관절학회 1996 대한슬관절학회지 Vol.8 No.1
Magnetic resonance imaging(MRI) is accepted as an useful tool for the diagnosis of injury of the knee recently. To evaluate the usefulness of MRI in the diagnosis of acute cruciate ligament tears, 28 cases of accute cruciate, ligament injuries(12 cases of anterior cruciate ligament(ACL) tears, 13 cases of posterior cruciate ligament(PCL) tears, and 3 cases of both ligament tears) were retrospectively reviewed with confirmatory tool of arthrotomy and arthroscopy. We applied 3 direct and 4 indirect MR criteria for ACL tears, and 2 direct MR criterial PCL tears. The results were as follows; 1. The accuracy of direct signs for ACL teats was 85.7%(sensitivity, 93.37%, specificity, 76.99% ). 2. The accuracy of direct signs for PCL tears was 89.3%(sensitivity, 93.8; specificity, 83.3% ). 3. The accuracy of indirect signs for ACL tears was 71.4%(sensitivity, 93.3%.; specificity, 46.2%). 4. The speciticity of MRI for the diagnosis of ACL tears was incrcased with direct signs combining with indirect signs (l00% in combination of direct sign with 2 or more indirect signs). 5. The diagnosis of ACL tears was more difficult than that of PCL, tear because of its thin and oblique course compared to PCL. 6. T2-weighted image was more helpful than T1-weighted image in the diagnosis of ligament tears. In conclusion, MRT is an useful tool for thc diagnosis of acute cruciate ligament tears. And the speciticity of MRI for the ctiagnosis of ACL tears was increased with direct signs combining with indireci signs.
Treatment of failing vein grafts in patients who underwent lower extremity arterial bypass
Keun-Myoung Park,Yang Jin Park,Shin-Seok Yang,Dong-Ik Kim,Young-Wook Kim 대한외과학회 2012 Annals of Surgical Treatment and Research(ASRT) Vol.83 No.5
Purpose: We attempted to determine risk factors for the development of failing vein graft and optimal treatment in patients with infrainguinal vein grafts. Methods: We retrospectively reviewed a database of patients who underwent infrainguinal bypass using autogenous vein grafts due to chronic atherosclerotic arterial occlusive disease of lower extremity (LE) at a single institute between September 2003 and December 2011. After reviewing demographic, clinical, and angiographic features of the patients with failing grafts, we analyzed those variables to determine risk factors for the development of failing grafts. To determine an optimal treatment for the failing vein grafts, we compared results of open surgical repair (OSR), endovascular treatment (EVT) and conservative treatment. Results: Two hundred and fifty-eight LE arterial bypasses using autogenous vein grafts in 242 patients were included in this study. During the follow-up period of 39 ± 25 months (range, 1 to 89 months), we found 166 (64%) patent grafts with no restenosis, 41 (15.9%) failing grafts, 39 (15.1%) graft occlusions, and 12 (4.7%) grafts lost in follow-up. In risk factor analysis for the development of a failing graft, no independent risk factors were identified. After 50 treatments of the 41 failing grafts (24 OSR, 18 EVT, 8 conservative management), graft occlusion was significantly more common in conservative treatment group and severe (>75%) restenosis was significantly more common following EVT than OSR (P = 0.001). Reintervention-free graft patency was also superior in the OSR group to that of the EVT group (87% vs. 42%, P = 0.015). Conclusion: OSR of failing grafts has better outcomes than EVT or conservative management in treating failing grafts.
Comparisons between prosthetic vascular graft and saphenous vein graft in femoro-popliteal bypass
Keun-Myoung Park,Young Wook Kim,Shin-Seok Yang,Dong-Ik Kim 대한외과학회 2014 Annals of Surgical Treatment and Research(ASRT) Vol.87 No.1
Purpose: Infrainguinalfemoropopliteal bypass (IFPB) is recommended to peripheral arterial disease (PAD) with a long occlusion of the superficial femoral artery (SFA). The aims of our study were to determine the patency of graft materials, and identify the risk factors of graft failure. Methods: From January 1995 to April 2011, we had performed 380 IFPBs in 351 patients, including 302 femoro-above the knee (AK) bypasses and 78 femoro-below the knee (BK) bypasses. We compare age, sex, severity of ischemia between polytetra-uoroethylene (PTFE) graft and saphenous vein (SV) graft, and evaluate patency rate rates of the two groups. Results: The primary patency rates at 5 years for SV (n = 76 limbs) and PTFE grafts (n = 226 limbs) in AK were 85.2% and 64.5% (log rank = 0.03), and the secondary patency rates at 5 years for SV and PTFE grafts in AK were 88.2% and 79.0% (log rank = 0.13). The primary patency rates at 5 years for SV (n = 50 limbs) and PTFE grafts (n = 28 limbs) in BK were 63.2% and 40.0% (log rank = 0.08), and the secondary patency rates at 5 years for SV and PTFE grafts in BK were 71.6% and 55.5% (log rank = 0.18). Conclusion: There was no statistical significant difference in secondary patency rates between SV and PTFE in IFPB. PTFE grafts as SV grafts can be a good alternative bypass material in IFPB instead of SV grafts.
Shin-Seok Yang,Keun-Myoung Park,Young-Nam Roh,Yang Jin Park,Dong-Ik Kim,Young-Wook Kim 대한외과학회 2012 Annals of Surgical Treatment and Research(ASRT) Vol.83 No.3
Purpose: The aim of this study was to assess renal or abdominal visceral complications after open aortic surgery (OAS) requiring supra-renal aortic cross clamping (SRACC). Methods: We retrospectively reviewed the medical records of 66 patients who underwent SRACC. Among them, 17 followed supra-celiac aortic cross clamping (SCACC) procedure, 42 supra-renal, and 7 inter-renal aorta. Postoperative renal, hepatic or pancreatic complications were investigated by reviewing levels of serum creatinine and hepatic and pancreatic enzymes. Preoperative clinical and operative variables were analyzed to determine risk factors for postoperative renal insufficiency (PORI). Results: Indications for SRACC were 25 juxta-renal aortic occlusion and 41 aortic aneurysms (24 juxta-renal, 12 supra-renal and 5 type IV thoraco-abdominal). The mean duration of renal ischemic time (RIT) was 30.1 ± 22.2 minutes (range, 3 to 120 minutes). PORI developed in 21% of patients, including four patients requiring hemodialysis (HD). However, chronic HD was required for only one patient (1.5%) who had preoperative renal insufficiency. RIT ≥ 25 minutes and SCACC were significant risk factors for PORI development by univariate analysis, but not by multivariate analysis. Serum pancreatic and hepatic enzyme was elevated in 41% and 53% of the 17 patients who underwent SCACC, respectively. Conclusion: Though postoperative renal or abdominal visceral complications developed often after SRACC, we found that most of those complications resolved spontaneously unless there was preexisting renal disease or the aortic clamping time was exceptionally long.
심근 좌상 환자에서 ^(99m)Tc-MIBI-Heart SPECT의 유용성
신중호,양혁준,이근,민순식,염석란,김재광,임용수,진욱,현성열 대한응급의학회 2002 대한응급의학회지 Vol.13 No.1
Purpose: This study analyzed the value of ^(99m)Tc-MIBI SPECT(Single Photon Emission Com-puted Tomography) in the deagnosis of myocardial contusion after blunt chest trauma. Methods: We evaluated 24 patients with cardiac contusions after blunt chest trauma who were diagnosed by clinical symptoms, chest x-ray, electrocardiogram(ECG), and Creatine phospho-kinase(CPK). ^(99m)Tc-MIBI SPECT was performed within 48 hours along with the above tests prospectively. Results: 1. Among the 24 patients, 14 patients were finally diagnosed as having a myocardial contusion by means of ECG, echocardiography, (^99m)Tc-MIBI SPECT, and cardiac enzyme. 2. The sensitivity, specificity and accuracy of ^(99m)Tc-MIBI SPECT were 46.7%, 66.7%, and 54.2%, respectively. The same results for initial ECG were 46.6%, 88.9%, and 62.5%. 3. For those who had positive findings in ^(99m)Tc-MIBI SPECT, average hospital stay was 14.5 days and abnormal electrocardiogram was found in 90.0%. However, for those who had negative findings, average hospital stay was 11.2 days and abnormal electrocardiogram was found in 35.7%. Conclusion: ^(99m)Tc-MIBI SPECT is not a definite modality in diagnosing myocardial contusion, but can be useful in diagnosing and determining the need for hospitalization after cardiac contusion.