• Journal of Chest Surgery
• /
• 제23권4호
• /
• pp.617-621
• /
• 1990

A heart supplies blood of about 15, 000 liters to each human organ in a day. A normal function of heart valves is necessary to accomplish these enormous work of heart. The disease of heart valve develops to a narrowness of a closure, resulting in an abnormal circulation of blood. In an attempt to eliminate the affliction of heart valves, the operative method to replace with artificial heart valves has developed and saved numerous patients over past 30 years. This replacement operation has been performed since early 1960`s in Korea, but all the artificial heart valves used are imported from abroad with very high costs until recent years. New artificial heart valves have been developed in Korea Advanced Institute of Science and Technology since early 1980`s. The first developed valve was designed with a free-floating pyrolytic carbon disk that is suspended in a titanium cage. The design of the valve was tested in vitro, and in animals in 1987. The results from this study was that the eccentrically placed struts creates a major and minor orifice when the disc opens and stagnation of flow in the area of the minor orifice has led to valve thrombosis. In this work, the design of the valve was changed from a single - leaflet valve to double - leaflet one in order to resolve the problems observed in the first - year tests. Morphological and hemodynamic studies were made for the newly designed valves through the in vitro and in vivo tests. The design and partial materials of the artificial heart valve was improved comparing with first - year`s model. The disc in the valve was modified from single - leaflet to bi - leaflet, and the material of the cage was changed from titanium metal to silicon - alloyed pyrolytic carbon. A test was made for the valve in order to examine its mechanical performance and stability. Morphological and hemodynamic studies were made for the valve that had been implanted in tricuspid position of mongrel dogs. All the test animals were observed just before the deaths. A new artificial heart valve was designed and fabricated in order to resolve the problems observed in the old model. The new valve was verified to have good stability and high resistance to wear through the performance tests. The hemodynamic properties of the valve after implantation were also estimated to be good in animal tests. Therefore, the results suggest that the newly designed valve in this work has a good quality in view of the biocompatibility. However, valve thrombosis on valve leaflets and annulus were found. This morphological findings were in accordance with results of surface polishing status studies, indicating that a technique of fine polishing of the surface is necessary to develop a valve with higher quality and performance.

• 한국지반공학회논문집
• /
• 제30권12호
• /
• pp.51-61
• /
• 2014

연구에서는 사질토 지반에서 개단말뚝의 지지력에 영향을 미치는 폐색효과를 조사하기 위하여 현장재하시험을 수행하였다. 현장재하시험은 직경이 다른 총 3본의 시험말뚝(508.0, 711.2, 914.4mm)을 제작하여 각각 동재하시험과 정재하시험을 실시하였다. 내주면마찰력과 외주면마찰력을 분리 측정하기 위하여 시험말뚝을 이중관으로 제작하였고, 외부말뚝의 안쪽과 내부말뚝의 바깥쪽 표면에 변형률계를 부착하였다. 정재하시험 결과, 내주면마찰력은 선단부로부터 총 관내토 길이의 약 18-34%의 부근에서 집중적으로 발생하였고, 이를 통해 말뚝 선단부근의 관내토가 내주면마찰력 발현에 큰 영향을 미치는 것을 알 수 있었다. 또한, 말뚝직경이 클수록 전체지지력에 대한 내주면마찰력과 순단면적의 선단지지력의 합의 비가 감소하는 것으로 나타났다. 그리고 말뚝의 폐색율을 정량화하기 위해 시험말뚝의 incremental filling ratio(IFR)를 측정하여 분석한 결과, SPT의 N값과 상관관계가 있는 것으로 나타났다.

• Journal of Chest Surgery
• /
• 제12권3호
• /
• pp.281-288
• /
• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• Journal of Chest Surgery
• /
• 제12권3호
• /
• pp.289-296
• /
• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• 수산해양기술연구
• /
• 제53권4호
• /
• pp.363-375
• /
• 2017

The age and growth of pointhead flounder, Hippoglossoides pinetorum caught by gill nets was analyzed in this study from March 2015 to July 2017. New annuli were formed in H. pinetorum otoliths annually, and the boundary was set between the opaque and translucent zones from March and April. The relationships between total length (TL) and body weight (BW) were $BW=0.0025TL^{3.409}$ ($r^2=0.9551$) for females and $BW=0.0057TL^{3.138}$ ($r^2=0.9163$) for males. In this study, the ring of pointhead flounder, H. pinetorum was formed between 3 and 8 for females and between 3 and 6 for males. Total length (TL) and otolith radius (OR) were measured as follows: TL = 7.142 OR + 0.769 ($r^2=0.793$) for females and TL = 6.498 OR + 1.706 ($r^2=0.652$) for males. The mean distances of first ring ($r_1$) were 0.92 mm and 0.91 mm for females and males respectively. The TLs at the time of annulus formation, back-calculated from the otolith-length relationship by reference to the von Bertalanffy growth curves, were $L_t=43.59(1-e^{-0.15(t+0.007)})$ for females and $L_t=28.13(1-e^{-0.26(t+0.006)})$ for males while the growth between female and male was different.

• 대한토목학회논문집
• /
• 제38권1호
• /
• pp.51-61
• /
• 2018

풍력발전기, 송전탑, 굴뚝 등과 같은 타워 구조물의 기초는 기초에서부터 하중 작용점까지의 거리가 멀고 큰 수평하중이 작용하여 매우 큰 전도모멘트에 저항해야 한다. 이러한 구조물을 경제적으로 지지하기 위해서는 암반층이라도 인발력을 받는 말뚝기초를 시공해야 한다. 따라서, 본 연구에서는 암반매입 강관말뚝에 사용되는 주면고정액의 배합비가 주면지지력에 미치는 영향을 평가하기 위하여 물/시멘트비와 잔골재의 배합비를 실험변수로 삼아 모형실험을 수행하였다. 잔골재를 배합하지 않은 시멘트풀의 경우 물/시멘트비의 변화에 관계없이 최대 주면지지력과 잔류 주면지지력은 일정한 범위에 분포하였고, 잔골재가 배합된 경우는 물/시멘트비의 증가에 따라서는 감소하였고 잔골재 배합비의 증가에 따라서는 증가하다 감소하는 경향을 나타내었다. 잔골재가 없는 경우 최대주면지지력은 물/시멘트비에 상관없이 약 540~560kPa을 나타내었고, 잔골재비가 40%인 경우 물/시멘트비에 따라 약 770~870kPa을 보여 잔골재가 없는 경우에 비하여 약 40~55% 증가되었다. 본 실험에서 찾은 최적배합은 잔골재비가 40% 정도, 물/시멘트비가 80~100% 이었다.

• Journal of Chest Surgery
• /
• 제41권2호
• /
• pp.268-272
• /
• 2008

판막주위농양은 판막륜과 주변조직의 감염성 괴사로 인하여 판막을 치환하기 전에 괴사된 조직의 제거와 첩포 재건술이 필요한 경우로 정의되며, 수술사망률과 합병증 및 재발률이 높은 것으로 알려져 있다. 본원에서는 13년전에 기계판막으로 승모판막치환술을 받은 59세 여자 환자에서 외래 추적 관찰중 발견된 판막주위농양에 의한 판막주위누출로 승모판륜재건술과 함께 승모판막치환술을 시행 받았으나, 술후 15병일째 판막주위누출이 재발하여 다시 승모판륜재건술 및 승모판막치환술을 시행 한 경우를 치험하여 보고하며, 환자는 수술후 8개월째 외래 경과관찰중이다.

• 한국어류학회지
• /
• 제8권2호
• /
• pp.16-22
• /
• 1996

한반도 서남 연안에서 채집된 붉바리의 이석을 이용하여 연령을 사정하고, 이석 윤문의 폭으로부터 체장을 역추정하여 체장과 체중의 성장을 추정하였다. 붉바리의 이석은 박편을 제작하여 암시야 현미경으로 관찰하면 연륜이 비교적 용이하게 구분되어 연령을 사정할 수 있었다. 붉바리의 주산란기는 7월이고 겨울에 연륜이 형성되기 때문에 각 연륜이 형성되었을 때의 나이는 연륜의 수에서 0.5를 감하였다. 관찰된 최대 연령은 9세이었으며, 최대 체장은 47.0cm이었다. 체장(L, cm)은 이석의 장반경(R, ${\mu}m$)에 유의하게 일차 비례하였다(L= -2.84+0.0070 R). 붉바리는 유어기에 이석의 성장이 체장에 비하여 상대적으로 빠른 것으로 보이며, 1세 이후는 체장과 이석의 성장이 비례하는 것으로 판단된다. 연륜이 형성되었을 때의 체장을 역추정한 각 나이별 평균 체장은 Von Bertalanffy의 성장식 Lt = 55.6[1-exp{-0.161(t+0.631)}]로 유의하게 나타낼수 있었다. 체장-체중(W, g)의 관계식 W=0.00608$L^{3.21}$을 이용하여 나이에 따른 체중(Wt) 성장식은 Wt=2422[1-exp{-0.161(t+0.631)}]$^{3.21}$로 표시되었다. 붉바리는 2세까지 성장률이 빨랐고, 그 이후 감소하지 만 5세 이후에도 비교적 높은 성장률을 보였다.

• 폴리머
• /
• 제37권6호
• /
• pp.669-676
• /
• 2013

탈미네랄화된 골분(demineralized bone particle, DBP)은 연골 형성의 유도인자로 사용되기 때문에 조직공학에서 널리 사용되는 생체재료이다. 본 연구에서는 in vivo 환경에서 디스크 재생 효과를 연구하기 위해 DBP를 poly(lactic-co-glycolic acid) (PLGA)에 첨가하여 다공성 지지체를 제조하였다. 디스크의 섬유륜 조직을 반으로 절개한 후, 수핵 조직을 제거하여 디스크 결손을 유발시켰다. 빈 공간에 PLGA, DBP/PLGA 지지체를 이식하여 in vivo 환경에서 조직공학적 디스크 재생을 관찰하였다. 1, 2 및 3개월 후 디스크를 적출하여 글리코스아미노글라이칸(glycosaminoglycan, sGAG) 및 콜라겐 합성 정도를 측정하였으며 조직학적 평가로 H&E, Safranin-O, Alcian blue 염색과 면역조직학적 평가로 제 I형 콜라겐, 제 II형 콜라겐 염색을 수행하였다. 그 결과 DBP/PLGA 지지체에서 sGAG 및 콜라겐 함량이 높은 것을 확인하였으며 추간판 디스크 재생의 가능성을 확인하였다.

• Journal of Chest Surgery
• /
• 제32권3호
• /
• pp.262-269
• /
• 1999

배경: 약 11년 동안의 대동맥판막치환술에 대한 중.장기임상성적을 알아보기 위해 대동맥판막 치환술을 시행하였던 환자들을 추적관찰하였다. 대상 및 방법: 1986년 2월부터 1997년 5월까지 134례의 대동맥판막치환술이 시행되었다. 남자가 71명, 여자가 63명이었고 평균 연령은 38.9세였으며 최저 17세에서 최고 70세의 연령범위를 보였다. 결과: 동반된 수술은 승모판치환술(62례), 승모판치환술과 삼첨판성형술(14례), 대동맥륜확대술(16례), Cabrol 술식(10례) 등이었다. 119개의 기계판막과 15개의 조직판막이 치환되었으며 21 mm 이하의 작은 판막이 68례에서 치환되었다. 술후 조기 합병증은 35례에서 발생하였는데 이 중 울혈성심부전 9례, 저심박출증 6례, 술후 출혈 5례, 흉막 삼출액 5례 등의 발생빈도를 보였다. 조기사망은 13례(9.7%)에서 발생하였으며 그 원인은 저심박출증(5례), 울혈성 심부전(2례), 범발성 혈관내 응고장애(2례) 등이었다. 총 추적기간 누계는 452.7 환자-년이었으며 평균 추적기간은 3.4$\pm$3.1 년/환자였다. 판막과 유관한 장기합병증은 9례에서 발생하였는데 항응혈제관련 출혈 4례, 심내막염 2례, 혈색전증 2례, 판막파괴 1례 등이 있었다. 추적기간 중 심장과 유관한 후기 사망은 5례(1.1%/환자-년)에서 발생하였으며 이 중 항응혈제관련 출혈이 2례, 심부전이 2례, 심내막염이 1례였다. 결론: Kaplan-Meier 방법에 의한 11년 보험 통계적 생존률은 91.0$\pm$4.3%였다.