• Journal of Chest Surgery
• /
• 제18권2호
• /
• pp.182-192
• /
• 1985

[here are so many reports that pulsatile blood flow provides physiologic organ perfusions during cardiopulmonary bypass. So, we compared the recent 30 cases undergoing cardiac surgery by Cobe-Stckert pulsatile roller pump with another 30 cases by Polystan nonpulsatile roller pump. Pulsatile flow was applied during aortic-cross clamping period when synchronized to internal EKG simulator, and perfusion mode was changed to continuous nonpulsatile flow after declamping of aorta. Age, sex, weight, and disease entities were comparable and operative techniques were similar between two groups. 1. There were no differences in average ACC time, ECC time, and Operation time. 2. Postoperative artificial respiration time was 6hrs 30mins in nonpulsatile group and 4hrs 48mins in pulsatile group, and detubation time after ventilator weaning was 2hrs 44mins in nonpulsatile group and 1hrs 43mins in pulsatile group. 3. Average pulse pressure was 8mmHg in nonpulsatile group and 55mmHg in pulsatile group, and a mean arterial pressure was 66.0mmHg in nonpulsatile group and 60.7mmHg in pulsatile group. 4. Mean urine-output during ACC;ECC period was 9.717.3;9.913.2ml/kg/hr in nonpulsatile group and 14.215.0;15.817.5 in pulsatile group [p<0, 05], and thereafter progressive decrease of differences in urine output between two groups until POD 2, and lesser amounts of diuretics was needed in pulsatile group during same postoperative period. Serum BUN/Cr level showed no specific difference and urine concentration power was well preserved in both groups. 5. Plasma proteins and other Enzymes showed no differences between two groups, but serum GOT/GPT level was higher in nonpulsatile group till POD 2. 6. Serum Electrolytes showed no differences between two groups. 7. WBC, RBC, Platelet counts, Hgb and Hct were not different and Coagulogram was well preserved in both groups. 8. Plasma free Hgb level was 7.09mg% in pulsatile group compared with 3.48mg% in pulsatile group on POD 1 but was normalized on POD 2. Gross hemoglobinuria after ECC was noted in 6 cases [20%] of pulsatile group and 4 cases [13%] of nonpulsatile group. 9. In both groups, most patients were included in NYHA class III to IV [28 cases;93% in nonpulsatile group, 22 cases;73% in pulsatile group] preoperatively, and well improved to class I to 11[22 cases; 73% in nonpulsatile group, 30 cases; 100% in pulsatile group] postoperatively. There were 7 operative mortalities in nonpulsatile group only, which were 5 cases of TOF with hepatic failure, 1 case of multiple VSDs with low out-put syndrome, and 1 case of mitral valvular heart disease with cardiomyopathy. We concluded that the new, commercially available Cobe-Stckert pulsatile roller pump device was safe, simple, and reliable.

• 대한수의학회지
• /
• 제39권2호
• /
• pp.247-256
• /
• 1999

A disease of young Holstein calves characterized by recurrent pneumonia, ulcerative and granulomatous stomatitis, enteritis with bacterial overgrowth, periodontitis, delayed wound healing, persistent neutrophilia and death at an early age had been originally described in 1983 and again in 1987. Most of these calves had stunted growth and a persistent, progressive neutrophilia (often exceeding 100,000/ml). By investigation of pedigrees, all of the affected calves have now been traced to a common sire and confirmed by polymerase chain reaction (PCR) diagnostic DNA testing to be homozygous carriers of a defective allele for bovine CD18. Neutrophils from these calves have several functional deficits and, most importantly, fail to adhere in a ${\beta}_2$-integrin dependent manner. The ${\beta}_2$-integrins represent a family of glycoproteins which participate in various leukocyte adhesion reactions during host defense. The presence or absence of ${\beta}_2$-integrin molecules can be demonstrated on the surface of neutrophils, monocytes and lymphocytes from normal or affected calves using specific monoclonal antibodies and flow cytometry, or by colloidal gold immunolabeling and scanning electron microscopy in backscatter mode. Deficiency of the ${\beta}_2$-integrins on all leukocyte types in Holstein calves is analogous to leukocyte adhesion deficiency (LAD) seen in humans. Neutrophils in bovine (BLAD) and human LAD patients are unable to adhere to the endothelial lining of the cardiovascular system thus interrupting egression of neutrophils into infected tissues. Other leukocytes, while still deficient in expression of the ${\beta}_2$-integrins, are still able to efficiently egress from the blood stream due to interactions of other adhesion molecules that are not as highly expressed on neutrophils. Both BLAD cattle and LAD children (who do not receive bone marrow transplants) often die at an early age as a result of the failure of neutrophils to extravasate into infected tissues. In 1991, Shuster, et $al^{27}$, identified two point mutations within the alleles encoding bovine CD18 in a Holstein calf afflicted with leukocyte adhesion deficiency. One mutation causes an aspartic acid to glycine substitution at amino acid 128 (D128G) in an extracellular region of this adhesion glycoprotein that is highly conserved (> 95% identity) between humans, cattle and mice. The other mutation is silent. Numerous calves with clinical symptoms of leukocyte adhesion deficiency have since been tested and all have been found homozygous for the D128G allele. In addition, calves homozygous far the D128G allele have been identified during widespread DNA testing in the United States. All cattle with the mutant allele are related to one bull, who through artificial insemination (A.I.), sired many calves in the 1950's and 1960's. The carrier frequency of the D128G CD18 allele among U.S. Holstein cattle had reached approximately 15% among active A.I. bulls and 8% among cows. By 1993, the organization of the dairy industry and the diagnostic test developed to genotype cattle, enabled virtually complete eradication of bovine leukocyte adhesion deficiency among current and future A.I. bulls.

• 대한치과보철학회지
• /
• 제43권5호
• /
• pp.599-610
• /
• 2005

Purpose: The success of the bonding between electroformed gold and ceramic is dependent on the surface treatment of the pure gold coping. The purpose of this study was to evaluate the bonding strength between the electroformed gold and ceramic with varying surface treatment. Materials and methods: A total of 32 disks,8 were using conventional ceramometal alloy, 24 were using electroforming technique as recommended by manufacturer, were prepared. 24 electroformed disks were divided 3 groups according to surface treatment, i.e. 50 microns aluminium oxide sandblasting(GES-Sand), gold bonder treatment(GES-Bond) and $Rocatec^{TM}$ system(GES-Rocatec). For control group of conventional alloy 50 microns aluminium oxide treatment was done(V-Supragold). Energy dispersive x-ray analysis and scanning electron microscope image were observed. Using universal testing machine, shear bond strength and bonding failure mode at metal-porcelain interface were measured. Results and Conclusion: The following conclusions were drawn: 1. In the energy dispersive x-ray analysis, the Au was main component in electroformed gold(99.9wt%). After surface treatment, a little amount of $Al_2O_3(2.4wt%)$ were found in GES-Sand, and $SiO_2(4wt%)$ in GES-Bond. In GES-Rocatec, however, a large amount of $SiO_2(17.4wt%)$ were found. 2. In the scanning electron microscopy, similar pattern of surface irregu larities were observed in V-Supragold and GES-Sand. In GES-Bond, surface irregularities were increased and globular ceramic particles were observed. In GES-Rocatec, a large amount of silica particles attached to metal surface with increased surface irregularities were observed. 3. The mean shear bond strength values(MPa) in order were $22.9{\pm}3.7(V-Supragold),\;22.1{\pm}3.8(GES-Bond),\;20.1{\pm}2.8(GES-Rocatec)\;and\;13.0{\pm}1.4(GES-Sand)$. There was no significant difference between V-Supragold, GES-Bond, and GES-Rocatec. (P>0.05) 4. Most bonding failures modes were adhesive type in GES-Sand. However, in V-Supragold, GES-Bond and GES-Rocatec, cohesive and combination failures were commonly observed. From the result, with proper surface treatment method electroformed gold may have enough strength compare to conventional ceramometal alloy.

• Journal of the Korean Wood Science and Technology
• /
• 제37권4호
• /
• pp.364-371
• /
• 2009

본 연구에서는 체적비 0.7%, 2.1%의 탄소섬유강화플라스틱 강화 낙엽송 집성재 보를 제작하여 휨강도 성능을 평가하였다. 휨강도 시험 결과 복합집성재의 파괴형상은 인장응력부 최하층에서 1차 파괴가 일어났지만 탄소 섬유 보강층 상층부는 파괴되지 않았다. 인장응력부위에서 1차 파괴가 일어난 후에도 보강층 상층부는 강도를 유지하고 있어 계속 하중이 증가하면 보강층 상층부에서 2차 파괴가 일어났다. 탄소섬유강화플라스틱 복합집성재의 휨강도는 체적비 0.7%를 보강한 집성재의 경우 대조군 집성재(control 재)에 비해 1차 파괴시 휨강도는 28% 향상되었다. 보강층 상층까지 완전한 파괴가 일어났을 때의 휨강도는 55% 향상되었다. 탄소섬유강화플라스틱을 체적비의 2.1% 보강한 경우 대조군 집성재에 비해 휨강도가 77% 증가하였다. Romani가 제안한 파괴모드를 이용하여 산출된 탄소섬유강화플라스틱 복합집성재의 예측 중립축과 스트레인 게이지로 측정된 실측 중립축의 높이가 1.03으로 잘 일치하는 것을 확인할 수 있었다.

• 대한조선학회논문집
• /
• 제54권2호
• /
• pp.151-160
• /
• 2017

Growing demand and rapid development of the synthetic fiber rope in mooring system have taken place since it has been used in deep water platform lately. Unlike a chain mooring, synthetic fiber rope composed of lightweight materials such as Polyester(polyethylene terephthalate), HMPE(high modulus polyethylene) and Aramid(aromatic polyamide). Non-linear stiffness and another failure mode are distinct characteristics of synthetic fiber rope when compared to mooring chain. When these ropes are exposed to environmental load for a long time, the length of rope will be increased permanently. This is called 'the creep phenomenon'. Due to the phenomenon, The initial characteristics of mooring systems would be changed because the length and stiffness of the rope have been changed as time goes on. The changed characteristics of fiber rope cause different mooring tension and vessel offset compared to the initial design condition. Commercial mooring analysis software that widely used in industries is unable to take into account this phenomenon automatically. Even though the American Petroleum Institute (API) or other classification rules present some standard or criteria with respect to length and stiffness of a mooring line, simulation guide considers the mechanical properties that is not mentioned in such rules. In this paper, the effect of creep phenomenon in the fiber rope mooring system under specific environment condition is investigated. Desiged mooring system for a Mobile Offshore Drilling Unit(MODU) with HMPE rope which has the highest creep is analyzed in a time domain in order to investigate the effects creep phenomenon to vessel offset and mooring tension. We have developed a new procedure to an analysis of mooring system reflecting the creep phenomenon and it is validated through a time domain simulation using non-linear mooring analysis software, OrcaFlex. The result shows that the creep phenomenon should be considered in analysis procedure because it affects the length and stiffness of synthetic fiber rope in case of high water temperature and permanent mooring system.

• 멤브레인
• /
• 제15권3호
• /
• pp.224-232
• /
• 2005

생체 폐를 대신해서 임시적으로 제공하는 폐 보조 장치(LAD)의 사용은 기계 환기술의 단순화와 체외순환 막형 인공폐의 기능을 결합하여 급성호흡부전 환자에 적합하다. 본 연구에서의 주 관심은 폐 보조 장치에서의 막 진동 효율에 있었으며 정량적인 실험 측정은 혈액 용혈에 대한 막 진동 의존을 확인하기 위하여 실행하였다. 또, 혈액 용혈은 막 진동이 이루어질 때 한계 용혈의 가진 주파수 대에서 결정하였다. 최대 기체 전달율을 보이는 675의 중공사 막으로 이루어져 있는 유형 5의 가진 주파수에서 최대 진폭의 발생 및 중공사에 진동의 전달에 의해 최대 산소 전달율이 일어났다. 이 주파수가 혈류량에 가동 가능했던 제 2 형태의 공진 주파수가 되어 높은 각 혈류량 비에서 $25{\pm}5$ 헤르쯔까지 가진이 되었으며, 혈액 용혈은 $25{\pm}5$ 헤르쯔의 가진 주파수에서 상대적으로 낮았다. 따라서 우리는 이 폐 보조 장치의 한계 용혈 주파수가 $25{\pm}5$ 헤르쯔인 것으로 결정했다.

• 접착 및 계면
• /
• 제8권2호
• /
• pp.15-21
• /
• 2007

광기능성시트 보호용 점착제를 제조하기 위하여 천연고무와 DCPD계 점착부여수지, 세 종류의 지방족 점착부여수지를 이용하여 천연고무계 점착제를 제조하였다. 또한, 천연고무의 낮은 응집력을 대체하기 위하여 점착부여수지의 함량이 고정된 상태에서 SIS 블록공중합체를 함량비에 따라 첨가하여 점착제를 제조하였다. 제조한 점착제의 점착물성을 초기점착력과 박리강도로써 평가하였다. 천연고무/점착부여수지의 초기점착력은 점착부여수지의 함량이 증가함에 따라 증가하다 최대값을 보이고 감소하였다. 또한, 지방족계 점착부여수지의 연화점이 증가함에 따라 초기점착력이 다소 증가하였다. 점착부여수지의 함량이 50 wt%까지는 박리강도가 증가하였으나 그 이상의 함량에서는 혼합파괴 현상을 보였다. SIS가 블랜드된 점착제의 초기점착력은 지방족계 점착부여수지의 함량이 20~40 wt%에서 최대값을 보였으나 20 wt%에서 fibrillation 현상을 나타내었고 박리강도는 40 wt%에서 최대값을 나타내었다.

• 콘크리트학회논문집
• /
• 제27권4호
• /
• pp.411-418
• /
• 2015

본 연구는 섬유혼입률 및 패널 두께가 구형비상체 충격에 의한 강섬유보강 콘크리트(SFRC) 패널의 손상특성에 미치는 영향을 알아보기 위하여 실시되었다. 실험체는 $200{\times}200mm$의 각형 패널로 계획하였으며, 두께는 30 및 50 mm로 설정하였다. 비상체는 직경 20 mm의 강재이며, 속도는 350 m/s로 실험을 실시하였다. 또한 본 연구에서는 SFRC의 역학적 특성과 내충격 성능의 상호관계를 평가하였다. SFRC의 역학적특성은 압축강도, 파괴계수 및 재료의 인성을 평가하였다. 비상체 충격에 의한 패널의 전면손실률은 압축인성이 증가함에 따라 감소하였고, 파괴계수 및 휨인성이 향상됨에 따라 배면손실률이 감소하는 것으로 나타났다. 강섬유보강 콘크리트의 동적특성 평가를 위하여, 상용 프로그램인 ABAQUS/Explicit를 사용하여 유한요소해석을 실시하였다. 해석결과 파괴양상이 유사한 경우 전면 및 배면손실률을 잘 예측하는 것으로 나타났다.

• The Journal of Advanced Prosthodontics
• /
• 제5권4호
• /
• pp.479-484
• /
• 2013

PURPOSE. The aim of this study was to evaluate the effects of additional acid etching and curing mechanism (light-curing or self-curing) of a composite resin on the dentin bond strength and compatibility of one-step self-etching adhesives. MATERIALS AND METHODS. Sixteen human permanent molars were randomly divided into eight groups according to the adhesives used (All-Bond Universal: ABU, Clearfil S3 Bond: CS3), additional acid etching (additional acid etching performed: EO, no additional acid etching performed: EX), and composite resins (Filtek Z-250: Z250, Clearfil FII New Bond: CFNB). Group 1: ABU-EO-Z250, Group 2: ABU-EO-CFNB, Group 3: ABU-EX-Z250, Group 4: ABU-EX-CFNB, Group 5: CS3-EO-Z250, Group 6: CS3-EO-CFNB, Group 7: CS3-EX-Z250, Group 8: CS3-EX-CFNB. After bonding procedures, composite resins were built up on dentin surfaces. After 24-hour water storage, the teeth were sectioned to make 10 specimens for each group. The microtensile bond strength test was performed using a microtensile testing machine. The failure mode of the fractured specimens was examined by means of an optical microscope at ${\times}20$ magnification. The data was analyzed using a one-way ANOVA and Scheffe's post-hoc test (${\alpha}$=.05). RESULTS. Additional etching groups showed significantly higher values than the no additional etching group when using All-Bond Universal. The light-cured composite resin groups showed significantly higher values than the self-cured composite resin groups in the Clearfil S3 Bond. CONCLUSION. The additional acid etching is beneficial for the dentin bond strength when using low acidic one-step self-etch adhesives, and low acidic one-step self-etch adhesives are compatible with self-cured composite resin. The acidity of the one-step self-etch adhesives is an influencing factor in terms of the dentin bonding strength and incompatibility with a self-cured composite resin.

• 한국안전학회지
• /
• 제25권6호
• /
• pp.34-39
• /
• 2010

본 연구는 건설현장에서 사용하고 있는 타워크레인에 대한 검사기관의 검사결과를 토대로 위험성과 중요도를 미리 검토하고 분석하여, 상호간의 검사 기준에 대한 판정기준을 정립하고 검사능력을 UP-Grade 시킬 수 있는 기회로 활용하기 위한 방안으로, 적절한 평가방법을 도입하여 객관적인 평가 모텔을 제시하는데 목적이 있다. 타워크레인은 건축물 또는 구조물 등, 건설현장에 설치되어 짧게는 2~3개월부터 2년 남짓 동안 지상에서 20~150M 이상 높은 곳으로 건설자재와 중량물 등을 실어 나르는 기계장치로, 건설 현장에서는 없어서는 안될 중요한 설비이다. 그러나 설치해서 사용하는 기간이 짧고, 건설 현장의 기술자들이 타워크레인에 대한 전문 기술력이 부족하여 체계적이고 정량적인 안전관리가 이루어지지 않고 있다. 이러한 문제점을 해결하기 위해서 전문가들의 지식과 경험을 바탕을 한 지식기반기법과 타워크레인에 적용 가능한 RBI절차 연구의 일환으로 정량적 위험우선순위를 FMEA기법을 활용하여 RPN을 적용시켜 보았다. 일반적인 RBI 80/20 Rule을 적용시켜 보았을 때, 위험도가 높은 부분은 와이어로프, 권과방지장치 및 브레이크와 권상감속기 등으로 나타났다. 하지만, 아직 타워크레인에 대한 위험분석이 제대로 이루어지지 않아 미흡한 부분이 많지만, 본 연구를 시작으로 좀 더 경험과 지식이 풍부한 전문가들이 나서서 중요 정보를 공유하고 data base화 하여, 타워크레인에 대한 활발한 RBI 기법의 보완과 지속적인 연구개발이 필요하다.