• Journal of Chest Surgery
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• 제44권1호
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• pp.32-38
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• 2011

Background: Surgical treatment of stage I non-small cell lung cancer (NSCLC) can be performed either by thoracotomy or by employing video-assisted thoracic surgery (VATS). The aim of this study was to evaluate the feasibility of VATS lobectomy for pathologic stage I NSCLC. Material and Methods: Between December 2003 and December 2007, 529 patients with pathologic stage I NSCLC underwent lobectomies (373 thoracotomy, 156 VATS). Patients in both groups were selected after being matched by age, gender and pathologic stage using propensity score method, to create two comparable groups: thoracotomy and VATS groups, and the overall survival, recurrence-free survival, complication and length of hospitalization were compared between these two groups. Results: After the patients were matched by age, gender and pathologic stage, 272 patients remained eligible for analysis, 136 in each group (mean age of 59.5 years; 70 men, 66 women; 80 stage IA, 56 stage IB). There was no statistical difference in other preoperative clinical characteristics between the two groups. No hospital mortality was observed in both groups. Overall 3-year survival rate was 97.4% in thoracotomy group and 96.6% in VATS groups (p=0.76). During the follow-up, 20 patients (14.7%) developed recurrence in thoracotomy group, including loco-regional recurrence in 7, distant metastasis in 13. In VATS group, 13 patients (9.6%) developed recurrence, including loco-regional recurrence in 4, distant metastasis in 9. Three-year recurrence-free survival rate was 81.8% in thoracotomy group and 85.3% in VATS groups (p=0.43). There was no significant difference in postoperative complications between thoracotomy and VATS groups (30 cases in 22 patients vs. 19 cases in 17 patients, p=0.65, odds ratio=1.19). The mean hospital stay of VATS group was 2 days shorter than that of thoracotomy group ($8.8{\pm}6.5$ days vs. $6.3{\pm}3.3$ days, p<0.05). Conclusion: VATS lobectomy for pathologic stage I lung cancer is a feasible operation with shorter hospitalization, while surgical outcome is comparable to thoracotomy lobectomy.

• 한국전기전자재료학회논문지
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• 제26권10호
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• pp.754-759
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• 2013

Aluminum oxide($Al_2O_3$) film deposited by atomic layer deposition (ALD) is known to supply excellent surface passivation properties on crystalline Si surfaces. Since $Al_2O_3$ has fixed negative charge, it forms effective surface passivation by field effect passivation on the rear side in p-type silicon solar cell. However, $Al_2O_3$ layer formed by ALD process needs very long process time, which is not applicable in mass production of silicon solar cells. In this paper, plasma-assisted ALD(PA-ALD) was applied to form $Al_2O_3$ to reduce the process time. $Al_2O_3$ synthesized by ALD on c-Si (100) wafers contains a very thin interfacial $SiO_2$ layer, which was confirmed by FTIR and TEM. To improve passivation quality of $Al_2O_3$ layer, the deposition temperature was changed in range of $150{\sim}350^{\circ}C$, then the annealing temperature and time were varied. As a result, the silicon wafer with aluminum oxide film formed in $250^{\circ}C$, $400^{\circ}C$ and 10 min for the deposition temperature, the annealing temperature and time, respectively, showed the best lifetime of 1.6ms. We also observed blistering with nanometer size during firing of $Al_2O_3$ deposited on p-type silicon.

• Journal of Chest Surgery
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• 제42권3호
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• pp.337-343
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• 2009

배경: 일차성 기흉 치료에서 비디오 흉강경수술 후 재발이 큰 문제이다. 이 연구는 기포 절제술 시에 재발 방지를 위해 자동봉합기의 봉합면에 흡수성 보강재(GORE $SEAMGUARD^{(R)}$)를 사용 후 안정성과 효과에 대해 조사하였다. 대상 및 방법: 2000년 1월부터 2004년 12월까지 성균관의대 마산삼성병원 흥부외과에서 일차성 기흉 치료에 흉강경 수술로 300명을 시행하였다. 143명(Group A)은 자동 봉합기 봉합선 보강재를 사용하였고, 142명(Group B)은 자동 봉합기만 사용하였다. 모든 환자에서 기계적인 흉막유착술을 시행하였다. 수술시간, 흉관 거치기간, 입원기간과 수술 후 재발된 환자 수를 비교하였다. 결과: 수술 후의 사망은 없었으며, 비디오 흉강경 수술에서 개흉술로 전환된 환자는 5% (15/300)였다. 두 군간의(Croup A versos Group B) 비교에서는 수술시간($49.6{\pm}25.6$ vs $51.8{\pm}30.4$ minutes, p=0.514), 흉관 거치기간($5.8{\pm}2.5$ vs $7.2{\pm}3.3$ days, p<0.005), 입원기간($10.9{\pm}4.3$ vs $12.5{\pm}4.3$ days, p<0.005), 그리고 재발률(14 (9.8%) vs 10 (7.0%), 전체 8.4%, p=0.523), 추적 관찰 기간($48.1{\pm}36.6$ vs $36.5{\pm}24.4$ months)의 차이를 보였다. 결론: 통상적인 방법의 수술보다 자동봉합기 봉합선 보강재를 사용한 군에서 흉관 거치기간과 입원기간에는 장점이 있었으나 재발률에는 영향이 없었다.

• 한국식품저장유통학회지
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• 제12권4호
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• pp.344-349
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• 2005

섬백리향의 항산화 기능성 성분에 대한 마이크로웨이브 추출특성을 확인하고자 microwave power($0{\sim}160\;W$)와 추출시간($1{\sim}5$분)을 독립변수($X_i$)로 하여 중심합성계획에 의해 10개구간의 추출조건을 설계하였다. 또한 추출물의 기능성분인 총 추출수율, 총 페놀 함량, 총 플라보노이드 함량 및 전자공여능을 종속변수($Y_n$)로 하여 반응표면분석을 실시하여 최적 추출조건을 예측하였다. 도출된 회귀식의 $R^2$는 총 페놀성분을 제외하고는 모두 0.93 이상을 나타내었으며, microwave power는 추출시간보다 영향이 큰 것으로 나타났다(p<0.05). 종속변수들의 최적 추출시간은 $3.36{\sim}4.97$분이었으나 microwave power는 넓은 분포를 보였으며, 기능성 성분들 모두를 추출하기 위한 추출조건 범위는microwave power $64{\sim}100\;W$, 추출시간 $2.9{\sim}4.0$분으로 나타났다.

• Clinical and Experimental Reproductive Medicine
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• 제48권1호
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• pp.69-79
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• 2021

Objective: Poor ovarian response (POR) refers to a subnormal follicular response that leads to a decrease in the quality and quantity of the eggs retrieved after ovarian stimulation during assisted reproductive treatment (ART). The present study investigated the associations of multiple variants of the estrogen receptor 2 (ESR2) and follicle-stimulating hormone receptor (FSHR) genes with POR in infertile Jordanian women undergoing ART. Methods: Four polymorphisms, namely ESR2 rs1256049, ESR2 rs4986938, FSHR rs6165, and FSHR rs6166, were investigated in 60 infertile Jordanian women undergoing ART (the case group) and 60 age-matched fertile women (the control group), with a mean age of 33.60±6.34 years. Single-nucleotide polymorphisms (SNPs) were detected by restriction fragment length polymorphism and then validated using Sanger sequencing. Results: The p-value of the difference between the case and control groups regarding FSHR rs6166 was very close to 0.05 (p=0.054). However, no significant differences were observed between the two groups in terms of the other three SNPs, namely ESR2 rs1256049, ESR2 rs4986938, and FSHR rs6165 (p=0.561, p=0.433, and p=0.696, respectively). Conclusion: The association between FSHR rs6166 and POR was not statistically meaningful in the present study, but the near-significant result of this experiment suggests that statistical significance might be found in a future study with a larger number of patients.

• 센서학회지
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• 제31권5호
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• pp.337-342
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• 2022

Hydrogen (H₂) gas is widely preferred for use as a renewable energy source owing to its characteristics such as environmental friendliness and a high energy density. However, H₂ can easily reverse or explode due to minor external factors. Therefore, H₂ gas monitoring is crucial, especially when the H₂ concentration is close to the lower explosive limit. In this study, metal oxide materials and their p-n heterojunctions were synthesized by a hydrothermal-assisted dip-coating method. The synthesized thin films were used as sensing materials for H₂ gas. When the H₂ concentration was varied, all metal oxide materials exhibited different gas sensitivities. The performance of the metal oxide gas sensor was analyzed to identify parameters that could improve the performance, such as the choice of the metal oxide material, effect of the p-n heterojunctions, and operating temperature conditions of the gas sensor. The experimental results demonstrated that a CuO/ZnO gas sensor with a p-n heterojunction exhibited a high sensitivity and fast response time (134.9% and 8 s, respectively) to 5% H₂ gas at an operating temperature of 300℃.

• Journal of Korean Neurosurgical Society
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• 제42권4호
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• pp.293-299
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• 2007

Objective : Thoracoscopic spinal surgery provides minimally invasive approaches for effective vertebral decompression and reconstruction of the thoracic and thoracolumbar spine, while surgery related morbidity can be significantly lowered. This study analyzes clinical results of thoracoscopic spinal surgery performed at our institute. Methods : Twenty consecutive patients underwent video-assisted thoracosopic surgery (VATS) to treat various thoracic and thoracolumbar pathologies from April 2000 to July 2006. The lesions consisted of spinal trauma (13 cases), thoracic disc herniation (4 cases), tuberculous spondylitis (1 case), post-operative thoracolumbar kyphosis (1 case) and thoracic tumor (1 case). The level of operation included upper thoracic lesions (3 cases), midthoracic lesions (6 cases) and thoracolumbar lesions (11 cases). We classified the procedure into three groups: stand-alone thoracoscopic discectomy (3 cases), thoracoscopic fusion (11 cases) and video assisted mini-thoracotomy (6 cases). Results : Analysis on the Frankel performance scale in spinal trauma patients (13 cases), showed a total of 7 patients who had neurological impairment preoperatively : Grade D (2 cases), Grade C (2 cases), Grade B (1 case), and Grade A (2 cases). Four patients were neurologically improved postoperatively, two patients were improved from C to E, one improved from grade D to E and one improved from grade B to grade D. The preoperative Cobb's and kyphotic angle were measured in spinal trauma patients and were $18.9{\pm}4.4^{\circ}$ and $18.8{\pm}4.6^{\circ}$, respectively. Postoperatively, the angles showed statistically significant improvement, $15.1{\pm}3.7^{\circ}$ and $11.3{\pm}2.4^{\circ}$, respectively(P<0.001). Conclusion : Although VATS requires a steep learning curve, it is an effective and minimally invasive procedure which provides biomechanical stability in terms of anterior column decompression and reconstruction for anterior load bearing, and preservation of intercostal muscles and diaphragm.

• Corrosion Science and Technology
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• 제2권2호
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• pp.93-97
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• 2003

Fatigue crack growth test or low alloy steel was performed in high temperature water. Test parameters were dissolved oxygen content. loading frequency and R-ratio ($P_{min}/P_{max}$). Since the sulfur content or the steel was low, there were no environmentally assisted cracks (EAC) in low dissolved oxygen(DO) water. At high DO, the crack growth rate at R = 0.5 tests was much increased due to environmental effects and the crack growth rate depended on loading frequency and maximized at a critical frequency. On the other hand, R = 0.7 test results showed an anomalous decrease of the crack growth rate as much different behavior from the R = 0.5. The main reason of the decrease may be related to the crack tip closure effect. All the data could be qualitatively understood by effects of oxide rupture and anion activity at crack tip.

• Bulletin of the Korean Chemical Society
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• 제13권6호
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• pp.599-605
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• 1992

Rate constants of methanolyses of para-Z-substituted benzenesulfonyl chlorides have been determined in various isodielectric solvent mixtures. A third-order kinetic behavior has been observed in the methanolysis of p-nitrobenzenesulfonyl chloride in methanol-nitromethane mixture from the correlation figure of logarithms of rate constants were plotted against Y-values based on solvolyses of 1-adamantyl tosylate. $S_N1$-$S_N2$ mixing mechanisms are favored by neutral or weak electron-donating and weak electron-withdrawing substituents of p-Z-substituted benzenesulfonyl chlorides in methanol-nitrobenzene mixture. While the methanolyses of para-Z-substituted benzenesulfonyl chlorides in methanol-ethylene glycol solvent mixture are appropriate for $S_N2$ mechanism from the mechanistic criterion by means of m-values.

• Clinical and Experimental Reproductive Medicine
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• 제48권2호
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• pp.163-173
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• 2021

Objective: This study aimed to characterize a validated model for predicting oocyte retrieval in controlled ovarian stimulation (COS) and to construct model-based nomograms for assistance in clinical decision-making regarding the gonadotropin protocol and dose. Methods: This observational, retrospective, cohort study included 636 women with primary unexplained infertility and a normal menstrual cycle who were attempting assisted reproductive therapy for the first time. The enrolled women were split into an index group (n=497) for model building and a validation group (n=139). The primary outcome was absolute oocyte count. The dose-response relationship was tested using modified Poisson, negative binomial, hybrid Poisson-E_max, and linear models. The validation group was similarly analyzed, and its results were compared to that of the index group. Results: The Poisson model with the log-link function demonstrated superior predictive performance and precision (Akaike information criterion, 2,704; λ=8.27; relative standard error (λ)=2.02%). The covariate analysis included women's age (p<0.001), antral follicle count (p<0.001), basal follicle-stimulating hormone level (p<0.001), gonadotropin dose (p=0.042), and protocol type (p=0.002 and p<0.001 for short and antagonist protocols, respectively). The estimates from 500 bootstrap samples were close to those of the original model. The validation group showed model assessment metrics comparable to the index model. Based on the fitted model, a static nomogram was built to improve visualization. In addition, a dynamic electronic tool was created for convenience of use. Conclusion: Based on our validated model, nomograms were constructed to help clinicians individualize the stimulation protocol and gonadotropin doses in COS cycles.