• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.176-177
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• 2013

Surface plasmon polaritons (SPPs) have attracted the attention of scientists and engineers involved in a wide area of research, microscopy, diagnostics and sensing. SPPs are waves that propagate along the surface of a conductor, usually metals. These are essentially light waves that are trapped on the surface because of their interaction with the free electrons of conductor. In this interaction, the free electrons respond collectively by oscillating in resonance with the light wave. The resonant interaction between the surface charge oscillation and the electromagnetic field of the light constitutes the SPPs and gives rise to its unique properties. In this papers, we studied theoretical and experimental extraordinary transmittance (T) and reflectance (R) of 2 dimensional metal hole array (2D-MHA) on GaAs in consideration of the diffraction orders. The 2d-MHAs was fabricated using ultra-violet photolithography, electron-beam evaporation and standard lift-off process with pitches ranging from 1.8 to $3.2{\mu}m$ and diameter of half of pitch, and was deposited 5-nm thick layer of titanium (Ti) as an adhesion layer and 50-nm thick layer of gold (Au) on the semiinsulating GaAs substrate. We employed both the commercial software (CST Microwave Studio: Computer Simulation Technology GmbH, Darmstadt, Germany) based on a finite integration technique (FIT) and a rigorous coupled wave analysis (RCWA) to calculate transmittance and reflectance. The transmittance was measured at a normal incident, and the reflectance was measured at variable incident angle of range between $30^{\circ}{\sim}80^{\circ}$ with a Nicolet Fourier transmission infrared (FTIR) spectrometer with a KBr beam splitter and a MCT detector. For MHAs of pitch (P), the peaks ${\lambda}$ max in the normal incidence transmittance spectra can be indentified approximately from SP dispersion relation, that is frequency-dependent SP wave vector (ksp). Shown in Fig. 1 is the transmission of P=2.2 um sample at normal incidence. We attribute the observation to be a result of FTIR system may be able to collect the transmitted light with higher diffraction order than 0th order. This is confirmed by calculations: for the MHAs, diffraction efficiency in (0, 0) diffracted orders is lower than in the (${\pm}x$, ${\pm}y$) diffracted orders. To further investigate the result, we calculated the angular dependent transmission of P=2.2 um sample (Fig. 2). The incident angle varies from 30o to 70o with a 10o increment. We also found the splitting character on reflectance measurement. The splitting effect is considered a results of SPPs assisted diffraction process by oblique incidence.

• Journal of Chest Surgery
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• 제41권6호
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• pp.729-735
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• 2008

배경: 이 연구는 일차성 자연 기흉 환자의 흉강경 수술 시, 부가적으로 시행한 경구용 tetracycline 흉막 유착술의 안전성과 효용을 평가하기 위해 시행되었다. 대상 및 방법: 2004년 3월부터 2007년 12월까지 본원 심장 센터에서 일차성 자연 기흉으로 비디오 흉강경 수술을 시행한 91예를 대상으로 하였다. 모든 환자에서 흉강경을 통해 폐 기포를 제거하고 벽측 흉막을 문질러 기계적 흉막 유착술을 시행하였다. 27예에서는 절개를 봉합하기 전에 트로카를 통하여 20 mg/kg의 경구용 tetracycline을 흉강 내로 주입하였다(Tetracycline군, 1군). 같은 기간 동안 tetracycline을 주입하지 않고 흉강경 수술만 시행한 나머지 64예를 대조군(2군)으로 하였다. 결과: 인구통계학적 데이터, 수술 소견, 수술 시간 등에서 두 군 사이에 유의한 차이는 없었다. 정주용 진통제가 필요했던 환자의 수와 기간은 두 군 사이에 비슷했으며, 공기 누출 기간과 합병증 발생률에서도 유의한 차이가 없었다. 술 후 평균 16개월($1{\sim}47$개월)의 추적 관찰 기간 동안 총 91예 중 7예(7.7%)에서 동측에 재발이 있었다. 재발은 모두 2군에서 발생하여 재발 예가 없는 1군에 비해 재발율이 높았으나 통계적 유의성은 없었다(0% vs 10.9%, p=0.099). 같은 기간 동안 재발 회피율 역시 1군에서 높은 경향을 보였으나 통계적 유의성에는 미치지 못하였다(p=0.077). 반면 2군에 비해 1군에서 술 후 흉관 거치 기간(4.2일 vs 3.5일, p=0.03)과 재원 일수(5.0일 vs 4.0일, p=0.006)가 유의하게 길었다. 결론: 이 연구에서 일차성 자연 기흉 환자의 흉강경 수술 시 부가적으로 시행한 경구용 tetracycline 흉막 유착술은 흉관 거치 기간과 재원 일수의 연장을 초래하였으나, 특별한 합병증 없이 안전하게 시행될 수 있음을 확인하였다. 또한 통계적 유의성에는 미치지 못하였지만, 술 후 재발율을 감소시키는 뚜렷한 경향을 보여 추가 연구의 필요성이 있다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권6호
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• pp.69-75
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• 2006

지하 저장 탱크로부터의 유류 유출로 인하여 전세계적으로 넓은 지역의 토양 및 지하수가 오염되고 있다. Methyl tert-butyl ether(MTBE)는 대기 오염 감소를 위하여 널리 사용되고 있는 유류 첨가제이지만 토양 및 지하수로 유입되어 섭취 되었을 때 발암 가능성이 있는 유독 물질이다. 본 연구는 고도 산화 처리 기법 중 유기 오염물의 분해에 높은 효율을 나타내는 고전적 Fenton reaction의 최대 단점인 강한 산성(pH 2.5-3) 의존성을 극복한 새로운 산화 처리 기법을 개발하여 고농도의 MTBE를 효과적으로 분해 하는 것을 그 목적으로 하여 자연 친화적인 chelating agents를 사용하여 중성 영역에서 Fenton reaction을 가능하게 하는 기법인 Modified Fenton reaction과 Ultra Violet light(UV)를 이용하여 분해효율을 극대화 하는 Photo-assisted Fenton reaction을 응용한 Modified Photo-Fenton reaction system을 개발하여 최적 반응 조건 및 반응 차수, 반응 메커니즘을 밝혀내었다. 낮은 독성과 높은 생분해성을 나타낸 Citrate ion을 chelating agents로 선정하였으며 최적 반응 조건은 [$Fe^{3+}$] : [Citrate] = 1 mM : 4 mM, 3% $H_2O_2$, 17.4 kWh/L UV dose, 초기 pH 6.0이며 이 조건에서 1000 ppm MTBE를 분해한 결과 6시간 후 86.75%, 16시간 후 99.99%의 높은 분해율을 나타냈으며 최종 pH는 6.02로 안정적이었다. 또한 Modified Photo-Fenton reaction을 이용한 MTBE 분해 반응은 유사 1차 반응을 나타내었으며 methoxy group이 ${\cdot}OH$ radical과 주로 반응하여 tert-butyl formate(TBF)가 주요 분해 산물이 되는 분해 경로를 따른 다는 것이 밝혀졌다. 본 연구로 개발된 Modified Photo-Fenton reaction에서 발생되는 산화제인 ${\cdot}OH$ radical의 비선택적 반응성을 고려할 때 본 system은 다른 종류의 유기 오염물 분해에도 효과적일 것으로 판단된다.

• 한국수정란이식학회지
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• 제16권3호
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• pp.193-201
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• 2001

본 연구에서는 DNA marker가 검정된 한우로부터 생산한 체외수정란을 이식하여 육질 및 육량의 유전적 능력이 우수한 한우를 대량생산하여 고품질 한우 쇠고기 생산 시스템을 구축하기 위한 전단계로서 DNA marker 검정 한우로부터 초음파유도 난포란을 채란하여 체외수성 및 수정란의 체외 발달에 미치는 각종 요인들과 배반포기 수정란의 부화율 개선을 위하여 투명대를 laser로 drilling을 실시하여 부화율을 조사하였다. 초음파유래 체외수정란의 분할률은 swim-up과 percoll 방법이 각각 75.0%(48/64) 및 71.4% (45/63)로써 이들간에 유의적인 차이는 없었고, 도축장유래 체외수정란의 분할율도 각각 69.9% (121/173) 및 62.2%(l12/180)로써 유의적인 차이가 없었다. 배반포기로의 발달율을 초음파유래 체외수정란이 25.0%(swim-up; 12/48) 및 22.2%(percoll; 10/45)로써 정자의 처리방법간에 유의적인 차이가 없었다. 초음파유래 체외수정란도 각각 29.8%와 28.6%로써 차이가 없었다. 초음파유래 난포란을 등급별로 분류하여 체외수정을 실시하였을 때 1(G I), 2(G II) 및 3(G III)등급 난포란의 분할율은 각각 60.0%(3/5), 69.2%(18/26) 및 62.1%(59/95)로써 이들간에 유의적인 차이는 없었으나, 4등급 난포란의 36.2%(25/69) 보다는 유의적(P<0.05)으로 높았다. 배반포기로의 발달율은 1 및 2등급이 33.3% (1/3) 및 38.7%(7/18)로써 3 및 4등급의 16.9% (10/59) 및 4.0%(1/25)보다는 유의적(P<0.05)으로 높았다 초음파유래 난포란을 체외수정 후 TFB, HT 및 HTB 배양액으로 체외배양을 실시하였을 때 분할율은 68.7%(55/80), 65.0%(13/20) 및 68.2% (15/22) 로써 유의적인 차이가 없었으며, 초음파유래 체외수정란의 배반포기로의 발달율은 TFB (25.5%), HT(23.1%) 및 HTB(20.0%)간에 유의적인 차이가 없었다. Laser system 으로 zona drilling을 실시한 EB, ExB 및 ExBO 수정란의 부화율은 각각 65.8%(25/38), 82.9%(29/35) 및 80%(16/20)로써 초음파유래 ExB 수정란이 가장 높게 나타났으며 (P<0.05), zona drilling 을 하지 않은 배반포기 수정란은 각각 25.0%(EB; 12/48) 및 35.7%(ExB; 15/42)로서 이들간에 유의적인 차이가 없었다. 그러나 zona drilling한 배반포기 수정란은 bona drilling을 하지 않은 배반포기 수정란에 비하여 부화율이 유의적(P<0.05)으로 높게 나타났다.

• 한국수정란이식학회지
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• 제33권3호
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• pp.185-194
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• 2018

The aim of this study was performed to evaluate the effects of ice-binding protein from the arctic yeast Leucosporidium (LeIBP) supplementation on cryopreservation of boar sperm. The collected semen was diluted ($1.5{\times}10^8/ml$) in lactose egg yolk (LEY) and cooled at $5^{\circ}C$ for 3 h. The cooled semen was then diluted ($1{\times}10^8/ml$) in LeIBP containing LEY with 9% glycerol and maintained at $5^{\circ}C$ for 30 min. The semen was divided into six experimental groups (control, 0.001, 0.005, 0.01, 0.05 and 0.1 mg/ml of LeIBP). The straws were kept on above the liquid nitrogen ($LN_2$) vapors for 20 minutes and then plunged into $LN_2$. After thawing, computer-assisted sperm analysis was used for sperm motility and flow cytometry was performed to assess the viability, acrosome integrity (FITC-PSA/PI), ROS (DCF/PI), lipid peroxidation (BODIPY C11/PI) and apoptosis (Annexin V/PI), respectively. No significant responses were observed for sperm motility. However, sperm viability was significantly increased on 0.05 and 0.1 mg/ml of LeIBP groups compared to control (P < 0.05). In addition, acrosome integrity was significantly increases LeIBP groups (P < 0.05) and both ROS and lipid peroxidation level were lower in all LeIBP groups than those of control (P < 0.05). On the other hand, a significant higher apoptosis rate was observed in 0.05 and 0.1 mg/ml of LeIBP groups compared to control (P < 0.05). It can be assumed that a supplementation of LeIBP in boar sperm freezing extender is an effective method to increase the sperm qualities after cryopreservation.

• 대한치과보철학회지
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• 제39권1호
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• pp.84-95
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• 2001

Titanium is widely used in dentistry for its low density, high strength, fatigue resistance, corrosion resistance, and biocompatibility. But it has a tendency of surface damage under circumstance of friction and impact for its low hardness of the surface. Coating is one of methods fir increasing surface hardness. Its effect is to improve surface physical characteristics without change of titanium. Diamond-like carbon and titanium nitride are known for its high hardness of the surface. So that this study was aimed at the wear test and the cytotoxicity test of the commercially pure titanium and Ti-6Al-4V alloy which were deposited by diamond-like carbon film or titanium nitride film to acertain improvement of the surface hardness and the biocompatibility. A disk (25mm diameter, 2mm thickness) was made of commercially pure titanium and Ti-6Al-4V alloy and these substrates were deposited by diamond-like carbon film or titanium nitride film. Diamond-like carbon film was deposited by the method of radiofrequency plasma assisted chemical vapor deposition and titanium nitride film was deposited by the method of reactive arc ion plating. Then these substrates were tested about wear characteristics by the pin-on-disk type wear tester in which ruby ball was used as a wear causer under the load of 32N, The fracture cycles were measured by rotating the substrates until their films were fractured. The wear volume was measured after 150 cycles and 3,000 cycles using surface profiler. The cytotoxicity test was peformed by the method of the MTT assay. The results were as follows : 1. In the results of the wear volume test, commercially pure titanium and titanium alloy which were coated by diamond-like carbon film or titanium nitride aim had higher resistance against wear than the substrates which were not coated by any films (P<0.05). 2. In the results of the fracture cycle test and the wear volume test, diamond-like carbon film had higher resistance against wear than titanium nitride film (P<0.05). 3. In both coatings of diamond-like carbon aim and titanium nitride film, Ti-6Al-4V alloy had higher resistance against wear than commercially pure titanium (P<0.05) 4. In the results of the cytotoxicity test, diamond-like carbon film and titanium nitride film had little cytotoxicity as like commercially pure titanium or Ti-6Al-4V alloy (P>0.05).

• Nutrition Research and Practice
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• 제15권3호
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• pp.367-381
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• 2021

BACKGROUND/OBJECTIVES: This study aimed to establish a mother and child cohort in the Chinese population, and investigate human breastmilk (HBM) composition and its relationship with maternal body mass index (BMI) and infant growth during the first 3 mon of life. SUBJECTS/METHODS: A total of 101 Chinese mother and infant pairs were included in this prospective cohort. Alterations in the milk macronutrients of Chinese mothers at 1 mon (T1), 2 mon (T2), and 3 mon (T3) lactation were analyzed. HBM fatty acid (FA) profiles were measured by gas chromatography (GC), and HBM proteomic profiling was achieved by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). RESULTS: During the first 3 mon of lactation (P < 0.05), significant decreases were determined in the levels of total energy, fat, protein, and osteopontin (OPN), as well as ratios of long-chain saturated FA (including C16:0, C22:0 and C24:0), monounsaturated FA (including C16:1), and n-6 poly unsaturated FA (PUFA) (including C20:3n-6 and C20:4n-6, and n-6/n-3). Conversely, butyrate, C6:0 and n-3 PUFA C18:3n-3 (α-linolenic acid, ALA) were significantly increased during the first 3 mon (P < 0.05). HBM proteomic analyses distinguished compositional protein differences over time (P = 0.001). Personalized motherinfant analyses demonstrated that HBM from high BMI mothers presented increased total energy, fat, protein and OPN, and increased content of n-6 PUFA (including C18:3n-6, C20:3n-6 and n-6/n-3 ratio) as compared with low BMI mothers (P < 0.05). Furthermore, BMI of the mothers positively correlated with the head circumference (HC) of infants as well as the specific n-6 PUFA C20:3n-6 over the 3 time points examined. Infant HC was negatively associated with C18:0. CONCLUSION: This study provides additional evidence to the Chinese HBM database, and further knowledge of FA function. It also helps to establish future maternal strategies that support the healthy growth and development of Chinese infants.

• Reproductive and Developmental Biology
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• 제37권1호
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• pp.17-22
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• 2013

Although assisted reproductive technology is very useful to develop novel and therapeutic biomaterials for reproduction, research on molecular mechanism of folliculogenesis in pig is not clear. Therefore, the alteration of gene expression during follicular development in pigs was examined in this study. The expression of folliculogenesis-related genes was quantified in preantral ($250{\sim}300{\mu}m$) and antral (> $300{\mu}m$ in diameter) follicles, and overall gene expression was evaluated by a genome-wide microarray. The microarray results showed that 219 genes were differentially expressed, and of those, 10 and 22 known genes showed higher and less expression at the preantral stage than at antral stages, respectively. Among them, the expression of NR0B1, PPARG, GATA4, and ANXA2 genes related to folliculogenesis was validated by quantitative real-time PCR analysis. The expression of PPARG and GATA4 genes were increased at antral stages, but a significantly stage-specific increase (p<0.05) was only detected in annexin A2 (ANXA2) in antral-stage follicles. The expression of NR0B1 genes was increased at preantral stage and these patterns of gene expression were comparable to the results obtained by microarray analysis. We propose that the systematical regulation of genes supporting specific follicle stage should be employed for improved in-vitro folliculognesis.

• Journal of Chest Surgery
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• 제43권6호
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• pp.687-693
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• 2010

배경: 자연 기흉으로 수술한 환자의 고해상도 CT에 보이는 반대편 기포 유무가 반대편 기흉 발생에 어떤 영향이 있는지 아직도 논란이 되고 있다. 저자들은 고해상도 CT에 보이는 반대편 기포 유무가 기흉 발생에 어떤 영향이 있는지와 기흉 발생의 위험 인자가 무엇인지에 대하여 연구하였다. 대상 및 방법: 2004년 l월부터 2009년 12월까지 본원에서 흉강경을 이용하여 수술 받은 자연 기흉 환자 394명을 대상으로 하였다. 이들 환자의 임상상과 고해상도 CT, 그리고 치료법에 대하여 후향적으로 조사하였다. 결과: 394명 중 28명 (7.10%)에서 반대편에 기흉이 발생했다. 발생까지의 기간은 13.06 (${\pm}9.79$) 개월이었다. 반대편에 기포의 유무가 반대편 자연 기흉 발생에 통계적으로 유의한 차이는 없으나(p=0.059) 반대편에 자연 기흉이 발생한 군에서 더 많은 기포수를 갖는 것으로 나타났다(p=0.011). 성별, 흡연 여부는 통계적으로 유의하지 않았다. 10대의 젊은 연령과 $18.5kg/m^2$ 이하의 체질량 지표가 통계적으로 유의하였으며 독립적 인 위험 인자로 나타났다(표본오차비율=0.04, 0.038, 0.00 각각). 결론: 자연 기흉으로 비디오 흉강경 수술 시행 받은 환자에서 고해상도CT에 보이는 기포와 크기는 반대편 자연 기흉의 발생에 영향이 없었다. 하지만 반대편 기흉이 발생한 군에서 기포수가 증가하는 경향이었고 10대인 젊은 연령과 체질량 지표가 $18.5kg/m^2$ 이하라는 위험 요인을 갖고 있었다. 따라서 이러한 환자들에 대하여는 외래 경과 추적 관찰을 자주하여 세심한 주의와 대중적인 치료가 필요할 것으로 판단된다.

• Journal of Gastric Cancer
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• 제15권3호
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• pp.191-200
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• 2015

Purpose: This study evaluated the functional and oncological outcomes of proximal gastrectomy (PG) in comparison with total gastrectomy (TG) for upper-third early gastric cancer (EGC). Materials and Methods: The medical records of upper-third EGC patients who had undergone PG (n=192) or TG (n=157) were reviewed. The PG group was further subdivided into patients who had undergone conventional open PG (cPG; n=157) or modified laparoscopy-assisted PG (mLAPG; n=35). Patients who had undergone mLAPG had a longer portion of their intra-abdominal esophagus preserved than patients who had undergone cPG. Surgical morbidity, recurrence, long-term nutritional status, and the incidence of reflux esophagitis were compared between the groups. Results: The rate of postoperative complications was significantly lower for PG than TG (16.7% vs. 31.2%), but the five-year overall survival rate was comparable between the two groups (99.3% vs. 96.3%). Postoperative levels of hemoglobin and albumin were significantly higher for patients who had undergone PG. However, the incidence of reflux esophagitis was higher for PG than for TG (37.4% vs. 3.7%; P<0.001). mLAPG was related to a lower incidence of reflux esophagitis after PG (P<0.001). Conclusions: Compared to TG, PG showed an advantage in terms of postoperative morbidity and nutrition, and there was a comparable prognosis between the two procedures. Preserving the intra-abdominal esophagus may lower the incidence of reflux esophagitis associated with PG.