• Journal of Chest Surgery
• /
• v.38 no.2 s.247
• /
• pp.164-167
• /
• 2005

Quadricuspid aortic valve is a rare congenital abnormality but it is well recognized as the cause of significant aortic regurgitation. We describe 5 patients who underwent surgery for severe aortic regurgitation associated with quadricuspid valve. In all patients, this abnormality had been incidentally detected during surgery. Two of the patients had infective endocarditis. In accordance with the Hurwitz and Roberts classification, two valves were type d, two were type a, and one was type c.

• Journal of Chest Surgery
• /
• v.14 no.4
• /
• pp.369-380
• /
• 1981

In this department 504 cases of valve replacement were done since 1968 to the end of October 1981. Since October 31, 1978 to the end of October 1981 ,333 Ionescu-Shiley bovine pericardial xenograft bioprosthetic cardiac valves were replaced in 265 patients. There were 149 males and 116 female. Ages ranged from 2 to 63 years with 25 cases under 15 years of age. Among 265 cases of Ionescu valve replacement there were 157 MVR, 36 VAR, 6 TVR, 45 MVR+ AVR, 16 MVR+TVR and 5 MVR+AVR+TVR cases with mortality of 5.7%, 8.3%, 16.7%, 8.9%, 18.8% and 20% for each group respectively. Over all mortality rate in 265 Ionescu valve replacement cases was 7.9% with 21 total deaths. Main causes of operative deaths were due to LCOS in 7, bleeding in 5, arrhythmia in 3, air embolism in 2,and heart block in 2 cases. There were 12 late complications with 6 deaths. Over all long-term survival rate was 89.8%. MVR showed the highest long-term survival rate with 92.4%, and MVR+AVR+TVR the lower with 80% lower with 80%.Average follow-up period was 14 month duration. Twenty five congenital anomaly cases were operated with Ionescu-valve replacement that consisted of 7 VSD+AI, and 5 Ebstein anomaly cases with over all operative mortality of 16% and late mortality of 14.3% among 21 operative survivors. There were 25 Ionescu valve replacement cases in pediatric patients under the age of 15 years, with 4 operative deaths. Fourteen MVR, 7 AVR, and 3 TVR cases were found. Even though long-term follow-up study was short in postoperative period with total of 33~.0 months among 244 operative survivors ranging one to 36 months, the late survivors showed beneficial long-term results two thromboembolic episodes in 244 patients were found. More cases and longer term follow-up study are warranted for valve replacement in pediatric and TVR cases with Ionescu-valves which have advantageous hemodynamic structures compared with other bio-prosthetic heart valves.

• Journal of the Korean Vacuum Society
• /
• v.14 no.4
• /
• pp.201-206
• /
• 2005

In this work, we tried to improve the fabrication process in HVPE (Hydride Vapor Phase Epitaxy) system by using Si(111) substrate with pre-deposited Al layer. PL measurements was done for samples with and without pre-deposited Al on Si and it was also examined the dependence of the optical characteristic properties on AlN buffer thickness for GaN/AIN/Al/Si. A sample with thin Al nucleation layer on Si substrate reveals a better optical property than the other. And it suggests that the thickness for AlN buffer layer with thin Al nucleation layer on Si(111) substrate is most proper about $260{\AA}$ to grow GaN in HVPE system. The surface morphology of GaN clearly shows the hexagonal crystallization. The XRD pattern showed strong peak at GaN{0001} direction.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.795-799
• /
• 2012

기후변화의 영향으로 인해 전 지구적으로 강우의 시 공간적 패턴이 변화하고 있으며, 우리나라의 경우 강우일수는 줄어들고 강우량은 증가하는 양상을 보일 것으로 전망하고 있다. 이는 강우현상이 발생할 경우 그 강도가 과거와 비교하여 강해지며, 가뭄 역시 그 심도가 보다 심각해질 수 있음을 의미한다. 이와 같이 기후변화에 의한 강우의 양상이 과거와 이질적으로 변화하고 있으므로 이를 고려한 물관리분야의 적응대책의 수립이 필요하다. 이를 위해서는 기후변화 영향에 따른 각 지역별 취약성 평가가 선결되어야 하며, 그 결과에 근거한 적응대책의 수립이 필요하다. 따라서 본 연구에서는 환경부 국립환경과학원에서 개발한 CCGIS를 이용하여 전라남도 22개 시 군의 물관리분야에 대한 취약성 평가를 수행하였다. CCGIS는 다양한 기후변화 시나리오 중 A1B 시나리오를 바탕으로 하고 있다. 치수의 취약성, 이수의 취약성, 수질 및 수생태에 대한 취약성을 대용변수(기후노출, 민감도 및 적응능력)를 이용하여 현재와 미래시점에 대하여 평가하였다. 먼저, 현재시점에서 전라남도 22개 시 군의 치수에 대한 취약성 평가 결과를 보면, 보성군이 가장 취약한 것으로 나타났으며, 나주시가 가장 양호한 것으로 분석되었다. 또한, 현재시점의 이수에 대한 취약성 평가에서는 목포시의 취약성이 타지역에 비해 현저히 높은 것으로 나타났으며, 고흥군이 가장 양호한 것으로 분석되었다. 수질 및 수생태에 대한 취약성 평가에는 구례군이 가장 취약하며, 목포시가 가장 양호한 것으로 나타났다. 미래시점(2050년대)의 치수에 대하여 상대적으로 취약한 지역은 순천시, 광양시, 구례군으로 조사되었으며, 따라서 이에 대한 방안 마련이 필요한 것으로 판단된다. 이수에 대해 상대적으로 취약한 지역은 목포시로 나타났으며, 전라남도 전역에 걸쳐 이수에 대한 취약성이 미래로 갈수록 낮아지는 경향을 보이고 있다. 수질 및 수생태에 대한 취약성 평가의 결과는 시 공간적으로 큰 변동이 없는 것으로 평가되었다.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.9 no.2
• /
• pp.167-171
• /
• 2004

We constructed an oligo-d(T) primed directional cDNA library from the Bombyx mandarina whole larvae. In an effort to isolate genes expressed in the B. mandarina, 227 expressed sequence tags (ESTs) were generated by single-pass sequencing from the cDNA library. Sequence analysis showed that 107 clones (47.1%) were classified into known genes and 120 clones (52.9%) were novel transcripts, which are unknown for their function. Of the 107 known genes, the most abundant gene was found to be actin and followed by serine protease in the expression profile. Among these clones, a serine protease homolog (BmSP) which is a class of proteolytic enzymes isolated. Full-length sequence of the BmSP cDNA clone was 922 bp in length and has an open reading frame of 276 amino acids. The conserved histidine, aspatic acid and serine residues forming the catalytic center as well as cysteine residues contributing to three disulphide bonds also were found in Bmsp gene. mRNA expression analysis revealed a high and specific expression of the gene only in midgut tissue, suggesting that BmSP gene is closely associated with the expression of digestive enzyme.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.20 no.2
• /
• pp.93-98
• /
• 2010

Bumblebees are widely used to pollinate various crops, especially tomato, in greenhouses and fields. An artificial hibernation is essential for year-round rearing of the bumblebee, which passes through one generation per year. Here, we investigated whether a chilling temperature and humidity affect artificial hibernation of the bumblebee queen Bombus terrestris. In chilling temperature regimes of $0^{\circ}C$, $2.5^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ or $12.5^{\circ}C$ under constant humidity >70%, the queens stored at $2.5^{\circ}C$ exhibited the highest rate of survival, which was 74.0% at one month, 67.0% at two months, 60.0% at three months, 46.0% at 4 months, 33.0% at 5 months, and 24.0% at 6 months. Rates of survival decreased at the following temperatures: $0^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ and $12.5^{\circ}C$. Colony developmental characteristics after diapause were 1.2- to 1.5-fold higher than those of queens stored at $5^{\circ}C$. In terms of chilling humidity, the queens hibernated at 70% under $2.5^{\circ}C$ exhibited the highest rate of survival, which was $93.3{\pm}3.4%$ at one month, $83.3{\pm}0.0%$ at two months, $76.7{\pm}0.0%$ at 3 months and $36.7{\pm}12.1%$ at 5 months. The rates of oviposition, colony foundation and progeny-queen production of queens hibernated at 70% were 80.8%, 30.8% and 30.8%, respectively. These values correspond to 1.7- to 3.3-fold increases in comparison to queens stored at 50% humidity. Therefore, $2.5^{\circ}C$ and 70% R.H. were the favorable chilling temperature and humidity conditions for diapause break of B. terrestris queens.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.14 no.2
• /
• pp.107-112
• /
• 2007

The mole crickets, Gryllotalpa, are insect pest distributed in the world. In Korea, G. orientalis was reported to occur, but previous ecological studies suggested the presence of two ecological types. To test this hypothesis, we sequenced a portion of mitochondrial (mt) genome from 48 G. orientali individuals collected over five Korean localities: Busan, Suwon, Okchon, Wonju, and Gangneung. From the sequence analysis, only two haplotypes were obtained, but the sequence divergence between the two haplotypes was 11 %, suggesting the presence of two distinct genetic groups in Korea. Although the population of Busan, Okchon, Wonju, and Gangneung was identified as a single haplotype, but that of Suwon was occupied by both hapotypes. Considering sequence divergence of other insect species occurring in Korea, the divergence estimate found between the two haplotypes seems to be too large to be considered as identical species. This result may suggest that the two differentiated haplotypes found in this study may reflect the previously reported two ecological types found in Suwon, Korea. To further understand the genetic divergence of the two phylogenetic groups, analysis of more variable regions of G. orientalis genome is required.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.158-158
• /
• 2010

본 연구에서는 분자선 박막성장 장비를 (MBE) 이용하여 droplet epitaxy 방법으로 성장시킨 GaAs/AlGaAs 양자점구조의 표면전기장변화에 관하여 photoreflectance spectroscopy (PR)를 이용하였다. 본 실험에 사용된 GaAs/AlGaAs 양자점 구조는 undoped-GaAs (001) 기판을 위에 성장온도 $580^{\circ}C$에서 GaAs buffer layer를 100 nm 성장 후 장벽층으로 AlGaAs을 100 nm 성장하였다. AlGaAs 장벽층을 성장한 후 기판온도를 $300^{\circ}C$로 설정하여 Ga을 3.75 원자층를 (ML) 조사하여 Ga drop을 형성하였다. Ga drop을 GaAs 나노구조로 결정화시키기 위하여 $As_4$를 beam equivalent pressure (BEP) 기준으로 $1{\times}10^{-4}$ Torr로 기판온도 $150^{\circ}C$에서 조사하였다. 결정화 직후 RHEED로 육각구조의 회절 페턴을 관측하여 결정화를 확인하였다. GaAs 나노 구조를 성장한 후 AlGaAs 장벽층을 성장하기위해 10 nm AlGaAs layer는 MEE 방법을 이용하여 $150^{\circ}C$에서 저온 성장 하였으며, 저온성장 후 기판온도를 $580^{\circ}C$로 설정하여 80 nm의 AlGaAs 층을 성장하고 최종적으로 GaAs 10 nm를 capping layer로 성장하였다. 저온성장 과정에서의 결정성의 저하를 보상하기위하여 MBE 챔버내에서 $650^{\circ}C$에서 열처리를 수행하였다. GaAs/AlGaAs 양자점의 광학적 특성은 photoluminescence를 이용하여 평가 하였으며 780 nm 근처에서 발광을 보여 주었다. 특히 PR 실험으로부터 시료의 전기장에 의한 Franz-Keldysh oscillation (FKO)의 변화를 관측하여 GaAs/AlGaAs 양자점의 존재에 의한 시료의 표면에 형성되는 표면전기장을 측정하였다. 또한 시료에 형성된 전기장의 세기를 계산하기위해 PR 신호로부터 fast Fourier transformation (FFT)을 이용하였다. 특히 온도의 존성실험을 통하여 표면전기장의 변화를 관측 하였으며 양자구속효과와 관련성에 대하여 고찰 하였다.

• Journal of Korea Water Resources Association
• /
• v.35 no.6
• /
• pp.753-762
• /
• 2002

In-stream vegetation is an essential element of a stream channel. Vegetation plays an important role in flood control and the natural environment in stream channels. This research investigates the relationship between in-stream vegetation and stream changes. This study investigates the distribution characteristic of vegetation in some rivers of Korea. Although there are many physical factors that cause changes to streams, this research verified that in-stream vegetation caused sediment deposition. A hydraulic model experiment was conducted. Tests were conducted in a simulated gravel bed stream (bed slope 1/200) with Phragmites japonica. The average diameter of the bed load used was 0.3 mm and 27 kg were uniformly supplied for 1 hour under same hydraulic conditions. The deposition and scouring as well as the change of flow differed according to the density and arrangement of the Phragmites japonica. In-stream vegetation and stream channel change are closely related because deposition and scouring affects the distribution of vegetation.

• Journal of Korea Water Resources Association
• /
• v.39 no.4 s.165
• /
• pp.289-298
• /
• 2006

Turbidity had been measured during five months In Han River estuary at three sites. In this process, missing data occurred due to gauge imitation of the turbidity sensor. A filling method for the missing turbidity data was newly developed in this study. Under the assumption of the time series data with unique period and different amplitudes, the new method can fill the missing data based on the area ratio of each cycle. And the new method was verified through the data set having no missing data. There were little differences between gross area of the original data and that of the revised data by the new method though values of peak were underestimated. As a result, missing turbidity data observed at Han River estuary could be appropriately filled using the new filling method.