• Archives of Plastic Surgery
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• 제40권1호
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• pp.11-18
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• 2013

Background To minimize the inflammatory reaction and improve healing, a new modified dermal substitute composed of an atelocollagen, chondroitin-6-sulfate, and amniotic membrane (AM) was applied to full-thickness skin defects in a pig. Atelocollagen was extracted from bovine skin, and two modified dermal substitutes were generated according to the cross-linking type. Methods The AM-collagen dermal substitutes were characterized and compared with currently used dermal substitutes in a pig skin defect model. There were five experimental groups: dehydrothermal (DHT) cross-linking atelocollagen with the AM on the top (AM-DHT), DHT and chemical cross-linking atelocollagen with the AM on the top (AM-DHT/chemical), Terudermis, Integra, and AlloDerm. After $3{\times}3cm$ full-thickness skin defects on the back of a pig were created, each dermal substitutes dermal substitutes was randomly grafted on the defects. Two weeks after grafting, autologous partial-thickness skin was over-grafted on the neodermis. The take rate of the dermal substitutes, skin, and histological sections were all assessed at 1, 2, and 4 weeks postoperatively. Results More rapid healing and a higher take rate were evident in the AM-DHT and Terudermis groups. Histological examination revealed fewer inflammatory cells and more fibroblast hyperplasia in these two groups. Four weeks after surgery, the amount of newly formed collagen was significantly more appropriate in the AM-DHT group. Conclusions These observations provide supporting evidence that a newly developed amniotic-collagen dermal substitute may inhibit inflammatory reactions and promote wound healing.

• 한국양식학회지
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• 제11권4호
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• pp.421-428
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• 1998

쥐노래미 사료의 어분 대체 단백질원으로서 대두박 및 우모분의 이용성을 검토하기 위해 어분을 주단백질원으로 한 대조사료와 대두박을 5%, 10%, 15% 및 20% 첨가한 실험구, 대두박 20% 첨가구에 제한적인 필수아미노산 보충구, 우모분을 5%, 10%, 15% 및 20% 첨가한 실험구, 그리고 대두박, 콘글루텐 밀, 육분, 혈분 및 우모분을 혼합하여 첨가한 실험구를 설정하여 11종의 실험사료를 설계하여 제조하였다. 21g 전후의 쥐노래미 치어를 2개월간 2반복으로 사육 실험한 결과, 증체율, 사료효율 및 단백질효율은 대두박을 20%까지 첨가한 실험구들에서 대두박 첨가비에 따라 다소 그 값이 낮아지기는 하였으나 대조구와 유의한 차이는 없었다(P>0.05). 또한 대두박 20% 첨가구에 필수아미노산 보충구도 대조구와 차이는 없었다(P>0.05). 그러나 우모분 첨가구들은 그 첨가비가 10%까지는 대조구와 차이가 없는 (P>0.05) 반면에 그 이상 첨가구들은 대조구보다 유의하게 낮은 값(P<0.05)을 보였다. 식물성 및 동물성 단백질원 혼합구는 대조구와 유의한 차이를 보이지 않았다(P>0.05). 이상의 결과로부터 대두박을 20% 첨가할 때 대조구 어분총량의 22%까지, 동물성 및 식물성 단백질 혼합 첨가시에는 대조구의 어분을 44%까지 대체할 수 있을 것으로 나타났다.

• 대한치과보철학회지
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• 제55권1호
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• pp.94-99
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• 2017

CAD/CAM (computer-aided design/computer-aided manufacturing) 기술을 이용한 인레이 및 여러 고정성 보철물의 제작이 보편화되고 구강내 스캐너가 널리 보급되면서 디지털 치의학의 개념이 치과 보철학 분야 전반에 적용되고 있다. 그러나 가철성 보철 부분에서는 디지털 개념의 적용이 쉽지 않으며 기존의 주조 방식에 많이 의존하고 있다. 따라서 가철성 보철물의 제작 과정에 이런 개념을 적용해보려는 시도는 중요한 의미가 있다. 본 증례에서는 하악 Kennedy class III 무치악 환자에서 보철적, 심미적 요구에 의한 교합고경의 증가와 함께 CAD 및 쾌속조형술(RP, rapid prototyping)을 이용한 가철성 국소의치를 제작하였다. CAD를 이용하여 서베잉 및 국소의치 금속 구조물을 설계하였으며, 쾌속조형술은 금속 구조물을 주조하기 위한 레진 패턴 제작에 이용하였다. 9개월 간의 임상적 관찰 기간 동안 만족스러운 심미적, 기능적 결과를 얻어 이를 보고하고자 한다.

• Advances in concrete construction
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• 제11권1호
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• pp.59-71
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• 2021

This research aims to study the utilization of olive waste ash (OWA) in the production of concrete as a partial substitute for cement. Effects of using OWA on the physical and mechanical properties of concrete mixtures have been investigated. This is done by carrying out tests involving the addition of various percentages of OWA to cement (0%, 5%, 10% and 15%). For each percentage, tests were performed on both fresh and hardened concrete; these included slump test, unit weight test and compressive strength test after 7, 28 and 90 days. Durability tests were investigated in solutions containing 5% NaOH and MgSO4 by weight of water. In addition, resistance to high temperatures was tested by subjecting the cubes to high temperatures of up to 170℃. The results of this research indicate that a higher percentage of OWA gives a lower compressive strength and lower workability but higher performance in terms of durability against both different weather conditions and high temperatures.

• 한국수정란이식학회지
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• 제23권1호
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• pp.19-24
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• 2008

The purpose of this study was to compare the efficiency of slow freezing with that of vitrification method for the cryopreservation of human embryos. Human embryos were derived from in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and the mixed solution of propanedial (1.5, 1.0, 0.5M PROH) and sucrose (0.1M), ethylene glycol (7.5, 15%), dimethyl sulfoxide (7.5, 15% DMSO), sucrose (0.5, 1.0M) and SPS (Serum Protein Substitute) was used for a cryoprotectant for slow freezing and vitrification solution, respectively. Rates of recovery after thawing, morphological normality, post-thaw viability, arrest, morphological abnormality and preimplantation development were compared between two protocols. After freezing-thawing, recovery and survial rate of slow freezing was (88.6% and 73.4%), whereas vitrification was (99.2% and 96.2%) (p<0.05). The arrest rate of slow freezing was significantly lower compared with those of vitrification(8.7% vs 29.9%) (p<0.05). Preimplantation development to the 2-cell (83.8% vs 67.7%), 4-cell (69.0% vs 47.2%) and 8-cell (62.4% vs 37.8%) stages 24, 48 and 72 h after thawing, respectively, were higher in the slow freezing than the vitrification. After slow freezing and vitrification of human embryo at 2-8cell stage, the rate of recovery rate, survival rate and partial damage rate were 92.0% vs 100%, 80.4% vs 96.2% and 52.2% vs 19.0%, respectively. And partial damage rate was significantly lower than those of slow freezing method (p<0.05). These results demonstrate that a slow freezing using PROH is more efficient than a vitrification for cryopreserving the human zygotes, although the vitrification yielded better recovery, survival and partial damage of frozen-thawed 2-8 cell stage embryos than slow freezing method.

• Structural Engineering and Mechanics
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• 제55권3호
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• pp.675-686
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• 2015

The use of ground granulated blast furnace slag (GGBFS) from steel industries waste is showing perspective application in civil engineering as partial substitute to cement. Use of such waste conserves natural resources and minimizes the space required for landfill. The GGBFS used in the present work is of ultra fine size and hence serves as micro filler. In this paper strength and durability characteristics of ultra fine slag based high strength concrete (HSC) (with a characteristic compressive strength of 50 MPa) were studied. Cement was replaced with ultra fine slag in different percentages of 5, 10, and 15% to study the compressive strength, porosity, resistances against sulfate attack, sorptivity and chloride ion penetration. The experiments to study compressive strength were conducted for different ages of concrete such as 7, 28, 56, and 90 days. From the detailed investigations with 16 mix combinations, 10% ultra fine slag give better results in terms of strength and durability characteristics.

• Structural Engineering and Mechanics
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• 제61권2호
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• pp.171-181
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• 2017

This paper summarizes the study on effect of ceramic waste powder as partial substitute to cement in binary blend and along with silica fume in ternary blend high strength concrete in normal and aggressive environments. Strength parameters such as compression & tension and durability indices such as corrosion measurement, deterioration, water absorption and porosity were studied. Ceramic waste powder was used in three different percentages namely 5, 10 and 15 with constant percentage of silica fume (1%) as substitutes to cement in ternary blend high strength concrete was investigated. After a detailed investigation, it was understood that concrete with 15% ceramic waste powder registered maximum performance. Increase of ceramic waste powder offered better resistance to deterioration of concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.327-328
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• 2009

본 연구는 시멘트 제조공정 중 입도분급을 통하여 채취한 미세입자의 시멘트를 치환한 모르터의 품질향상을 위해 고로슬래그 미분말 및 석고 자극제를 치환한 경우의 실험으로써, 유동성 및 조기강도는 저 하하였으나 28일 일부 압축강도는 증가하는 것으로 나타났다.

• 한국안전학회지
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• 제12권4호
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• pp.180-190
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• 1997

A new method in the fault tree analysis (FTA) for the reliability calculation is suggested. Two steps are necessary in traditional method in evaluation of the occurrence probability of top event in fault tree (FT). The first step is to find the minimal outsets, and the second one is to substitute the result into the poincare equation. In order to reduce the enormous computing time of this method, lots of rapid algorithms have been developed. Almost of all achievements were, however, based on the partial structural properties of FT. In this paper, the FT is transformed to a non-linear graph G which has the same minimal outsets of original n, and then the reliability is calculated using the domination theory. In this new method, the required number of equation terms are at most $2^n$ (n is node number of graph G), while $2^m$-1 (m is the number of minimal cutsets) calculation terms are required in the poincare equation in traditional method. Since m>>n in general. our new method reduces the calculation time significantly.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 지반환경 및 준설매립에관한 학술세미나
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• pp.72-84
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• 2001

In order to utilize mass of oyster shells for a partial substitute material for reclamation, we investigate the shear characteristics of dredged sluge mixed with oyster shells. the apparent modulus of elasticity of the this mixture are obtained from the triaxial compression tests and is utilized to characterize the apparent modulus of elastic of the oyster shells by carrying out some numerical analysis based upon the homogenization theory. We got the conclusion by a series of experiment, 1) It is verified that modulus of elasticity of dredged clay is improved by mixing with oyster shells. 2) The homogenization method for deducing apparent modulus of elasticity of oyster shells, which can consider micro-structure of mixed soil, is introduced. The elastic modulus is affected from the skeleton structure of oyster shell. The effect of 49kPa is bigger than that of 98kPa.