• Steel and Composite Structures
• /
• 제13권6호
• /
• pp.587-606
• /
• 2012

Concrete-filled-steel-tubular (CFST) columns have been well proven to improve effectively the strength, stiffness and ductility of concrete members. However, the central part of concrete in CFST columns is not fully utilised under uni-axial compression, bending and torsion. It has small contribution to both flexural and torsion strength, while it can be replaced effectively by steel with smaller area to give similar load-carrying capacity. Also, the confining pressure in CFST columns builds up slowly because the initial elastic dilation of concrete is small before micro-crackings of concrete are developed. From these observations, it is convinced that the central concrete can be effectively replaced by another hollow steel tube with smaller area to form double-skinned concrete-filled-steel-tubular (CFDST) columns. In this study, a series of uni-axial compression tests were carried out on CFDST and CFST columns with and without external steel rings. From the test results, it was observed that on average that the stiffness and elastic strength of CFDST columns are about 25.8% and 33.4% respectively larger than CFST columns with similar equivalent area. The averaged axial load-carrying capacity of CFDST columns is 7.8% higher than CFST columns. Lastly, a theoretical model that takes into account the confining effects of steel tube and external rings for predicting the uni-axial load-carrying capacity of CFDST columns is developed.

• 한국항공우주학회지
• /
• 제48권2호
• /
• pp.127-134
• /
• 2020

고초음속 항공기는 초음속 비행 중 공력 가열에 의하여 높은 온도 환경에 노출되기 때문에 동체 및 날개 구조물은 더블 패널 형태의 열 차폐 구조로 설계하여 기체 내부로 높은 온도의 열이 전달되는 것을 막는다. 얇은 두께의 더블 패널 외피는 초음속 항공기의 고출력 엔진 소음과 제트 유동에 의한 음향 하중에 노출되어 음향 피로 손상이 발생할 수 있다. 따라서 열음향 복합 하중을 받는 초음속 항공기 외피 구조의 거동 확인과 피로수명 예측이 필요하다. 본 논문에서는 열음향 복합 하중을 모사할 수 있는 열음향 시험 장치를 설계/제작하여 열음향 하중이 적용되는 티타늄 시편의 열음향 시험을 수행하였다. 열음향 복합 하중에 의한 구조물의 동적 거동을 확인하였으며, 시편 단위 열음향 시험 결과와 유한요소해석 결과를 비교하여 해석 모델을 검증하였다.

• 공업화학
• /
• 제34권2호
• /
• pp.161-169
• /
• 2023

본 연구는 allbanggae starch (ABS), polyvinyl alcohol (PVA), alginic acid (SA)를 이용하여 naproxen (NP) 각인 starch 기반 다층 바이오소재를 제조하고, 물리화학적 특성과 약물 방출 제어 효과를 조사하였다. 또한, FE-SEM과 FT-IR 분석에 의해 제조한 다층 바이오소재의 특성을 조사하였다. 약물 방출 제어 효과와 경피 약물 전달 시스템의 적용 가능성을 확인하기 위해 NP 각인 다층 바이오소재로부터 NP 방출 특성을 사람의 체온인 36.5 ℃에서 다양한 pH buffer solution과 인공 피부를 이용하여 확인하였다. NP는 낮은 pH보다 높은 pH에서 1.3배 더 빠른 방출을 나타냈고, single-layer 바이오소재에서보다 multi-layer 바이오소재에서 약 4.0배 느린 방출이 일어남을 확인하였다. 인공 피부 방출에서도 동일하게 single-layer 바이오소재보다 multi-layer 바이오소재에서 약 4.0배 더 느린 약물 방출 결과를 나타내었다. 또한, double-layer와 triple-layer 바이오소재 모두 12시간 동안 지속적으로 NP가 방출되었음을 확인 하였다. NP 방출 mechanism을 규명하기 위해 수학적 모델링에 적용하여 비교했을 때, pH buffer solution에서의 방출은 Fickian diffusion mechanism, 인공 피부 방출은 empirical mechanism에 적합한 것을 확인하였다.

• Archives of Reconstructive Microsurgery
• /
• 제11권1호
• /
• pp.11-18
• /
• 2002

Large soft tissue defects around the knee joint are known to significantly diminish joint function. Severe soft tissue defects on the anterior aspect of the knee joint especially bring on significant joint motion limitation. Although simple split skin grafts can cover the skin defect, the progressing scar contracture of the grafted skin causes joint stiffness. One of the best solutions of large soft tissue defects around the knee joint is covering the defect with a good quality skin flap. Separated flaps with one vascular pedicle are good candidates for covering anterior and posterior aspects of the joint for example. Authors performed 12 cases of combined scapular and latissimus dorsi free flaps from 1984 to 2000. Among them, we experienced 5 cases of knee joint defect covering using the double free flap for coverage of the soft tissue defect with preservation of the knee joint function and satisfactory results. The system of flaps based on the subscapular artery and vein provides a variety of composite free flaps. The possible flaps that can be harvested based on this single vascular pedicle include the scapular and parascapular skin flap, the serratus anterior and latissimus dorsi muscular flap, the lateral scapular bone flap, the latissimus dorsi-rib flap, and the serratus anterior-rib flap. This combined flap is available for multiple tissue defects or complex defects because it can be incorporated with skin, muscle and bone flaps. A main advantage is the independent vascular pedicles of each component, which allow freedom in orientation of each components. Consequently it can be freely applied to any form of three dimensional defects on the upper and lower extremities. The combination of scapular cutaneous flap and latissimus dorsi musculocutaneous flap can be resurfaced for massive cutaneous defects on the extremities. We report the use of the combined scapular and latissimus dorsi free flap in five patients to reconstruct massive defects on the extremities with resultant improved joint function. There was no flap failure and minimal complications and disadvantages. The anatomy of this flap is reviewed and the indication and advantages are discussed. All of the five flaps survived and there was no scar contracture affecting the joint motion.

• 대한화장품학회지
• /
• 제25권4호
• /
• pp.1-5
• /
• 1999

The purpose of this study was to determine the effect of IPBC(3-lodo-2-propynylbutylcarbamate) on dandruff caused by the anthropophilic fungus Malassezia furfur. The effects of IPBC on dandruff were examined by evaluating (a) the MIC value of IPBC using broth dilution method; (b) the remnant antimicrobial activity of IPBC containing shampoo on skin disc; (c) the antidandruff efficacy of 1.0 % IPBC containing shampoo in double blind clinical trial. To investigate the remnant antimicrobial activity of IPBC against Malassezia furfur, guinea pig-skin disc was washed with antidandruff shampoo and then the diameter of inhibition zone per disc was measured. For clinical trial, thirty healthy volunteers, aged 25-35, participated in 4 week study. At 0, 2, 4 weeks, examinations of scaling, itching on scalp were carried out. The MIC(Minimun Inhibition Concentration) values of IPBC range from 0.10 to 1.00${\mu}g/ml$ and it seems that IPBC is more effective in the MIC values than zinc pyrithione, selenium disulphide, piroctone olamine and comparable to ketoconazole, climbazole. When the remnant antimicrobial activity of IPBC shampoo on skin disc was determined, 0.5% IPBC shampoo and 2.0% Ketoconazole shampoo resulted in similar antimicrobial effect. In addition, 1.0%, 2.0% IPBC shampoo was more effective than 2.0% ketoconazole shampoo. After two and four-weeks of 1.0% IPBC shampoo treatment, there was significant reduction of scaling, itching in test group compared to control group. On the basis of these results, it can be concluded that 1.0% IPBC is more effective than 2.0% Ketoconazole in reducing dandruff. It seems that strong capacity of drug binding to the stratum corneum plays a role in its antidandruff effect since adsorption of active ingredients on scalp is very important factor in reducing dandruff.

• 한국환경보건학회지
• /
• 제36권4호
• /
• pp.337-341
• /
• 2010

The modified simultaneous differential staining technique, which enables double staining of cartilage and bones, needs to be improved to prevent soft tissues from being damaged during the staining process. Key factors influencing the extent to which soft tissues are damaged include the fixative used, macerating time, potassium hydroxide concentration, incubation temperature and the removal of skin from specimens. Here we describe a protocol that enables the hardening of tissues during bleaching and maceration. We also describe a method for objectively measuring rates of cartilage and bone growth. The use of formalin as a fixative rendered soft tissues more rigid due to the resulting chemical bonds formed between proteins. Blotted specimens were immersed in 1% potassium hydroxide (KOH) and incubated at $37^{\circ}C$ for 1 day (smaller specimens) or 2-3 days (larger specimens). The 1% KOH solution was also used as the diluent solution for the subsequent immersion in a graded series of 30%, 50%, 70%, 90%, 100% glycerol solutions, a procedure that made soft tissues even more transparent and hardened. It was not necessary to remove the skin of specimens shorter than 2 cm, since the macerating solution could easily penetrate their thin skin layer and continuously remove those pigments hindering visibility. Since excessive osmosis is another factor that can damage soft tissues in the macerating process by causing the rupture of those cells not able to withstand the osmotic pressure, here it was minimized by balancing the salt concentration between the interior and exterior of cells with the addition of 0.9% sodium chloride (NaCl) in the macerating solution. Finally, to determine the proportions of cartilage and bone growth, photographs of the stained specimens were taken with a dissecting microscope and sections corresponding to the cartilage and bones were cut out from the printed pictures and weighed. Our results show that this method is suitable for the objective evaluation of bone and cartilage growth.

• 대한화장품학회:학술대회논문집
• /
• 대한화장품학회 1999년도 IFSCC . ASCS 학술대회 발표 논문
• /
• pp.1-5
• /
• 1999

The purpose of this study was to determine the effect of IPBC(3-lodo-2-propynylbutyl carbamate) on dandruff caused by the anthropophilic fungus Maiassezia furfur. The effects of IPBC on dandruff were examined by evaluating (a) the MIC value of IPBC using broth dilution method : (b) the remnant antimicrobial activity of IPBC containing shampoo on skin disc ; (c) the antidandruff efficacy of 1.0 % IPBC containing shampoo in double blind clinical trial. To investigate the remnant antimicrobial activity of IPBC against Maiassezia furfur, guinea pig-skin disc was washed with antidandruff shampoo and then the diameter of inhibition zone per disc was measured. For clinical trial, thirty healthy volunteers, aged 25-35, participated in 4 week study. At 0,2,4 weeks, examinations of scaling, itching on scalp were carried out. The MIC(Minimun Inhibition Concentration) values of IPBC range from 0.10 to 1.00$\mu$ g/ml and it seems that IPBC is more effective in the MIC values than zinc pyrithione, selenium disulphide, piroctone olamine and comparable to ketoconazole, climbazole. When the rimnant antimicrobial activity of IPBC shampoo on skin disc was determined, 0.5% IPBC shampoo and 2.0% Ketoconazole shampoo resulted in similar antimicrobial effect. In addition, 1.0%,2.0% IPBC shampoo was more effective than 2.0% ketoconazole shampoo. After two and four-weeks of 1.0% IPBC shampoo treatment, there was significant reduction of scaling, itching in test group compared to control group. On the basis of these results, it can be concluded that 1.0% IPBC is more effective than 2.0% Ketoconazole in reducing dandruff. It seems that strong capacity of drug binding to the stratum corneum plays a role in its antidandruff effect since adsorption of active ingredients on scalp is very important factor in reducing dandruff.

• 한국식품저장유통학회지
• /
• 제10권4호
• /
• pp.447-453
• /
• 2003

얼룩과는 배 재배중에 사용하는 봉지 종류에 따라 수확시발생률이 다른데 흡습성과 투기성이 불량한 이중 봉지인 신문 봉지를 사용한 경우 수확시 발생률이 75%로 가장 높았으며 저온 저장중에는 습도가 높을수록 많이 발생하여 저장 180일까지 폴리에틸렌 필름 밀봉구에서 54～100% 까지 발생하였다 또한 수확 시기가 늦어질수록 얼룩과 발생이 많아져 관행 수확기보다 일주일 빠른 9월 하순에 수확한 배보다 10월 초순이나 10월 중순에 수확한 배는 저장중에 각각 1.5, 2.4배나 높은 발생률을 보였고 저장중 폴리에틸렌 필름두께에 따라서는 얼룩과 발생률이 차이가 없었다. 얼룩과의 발현 원인이 미생물로 추정되어 과피에서 분리균을 채취, 배양하여 형태적으로 관찰한 결과, 원인균은 Gloeodes pomigena와 유사한 균으로 추정되었다. 저온 저장고 내에서 0.1～0.5ppm의 오존 가스를 처리하면 저장 180일까지 얼룩과가 전혀 발생하지 않았으며 얼룩과 발생 이후에 오존 가스를 처리해도 얼룩과의 진전을 막을 수 있었다.

• Journal of Chest Surgery
• /
• 제32권3호
• /
• pp.307-309
• /
• 1999

판막수술 후 반드시 투여해야 하는 항응고제로 인한 피부괴사증은 매우 드문 합병증으로 기전은 아직 확실히 밝혀지지는 않았지만 항응고제의 초기 투여시 제2, 9, 10 응고인자에 비해 C 단백질이 급격하게 감소하기 때문에 나타나는 일시적인 과응고 현상이다. 저자들은 다중판막 치환술 1개월 후에 양측 유방부위에 발생한 광범위한 피부괴사증을 경험하였다. 진단 즉시 \ulcorner파린 투여를 중단하고 저분자량의 헤파린으로 대치하였으며 피부괴사증은 5일 후 치유가 되었고 그 후 다시 와파린 투여를 저용량부터 시작하여 서서히 증량해가며 저분자량 헤파린 투여를 중단할 수 있었기에 문헌 고찰과 함께 보고하는 바이다.

• Biomolecules & Therapeutics
• /
• 제30권1호
• /
• pp.72-79
• /
• 2022

Licochalcone H (LCH) is a phenolic compound synthetically derived from licochalcone C (LCC) that exerts anticancer activity. In this study, we investigated the anticancer activity of LCH in human skin cancer A375 and A431 cells. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell viability assay was used to evaluate the antiproliferative activity of LCH. Cell cycle distribution and the induction of apoptosis were analyzed by flow cytometry. Western blotting assays were performed to detect the levels of proteins involved in cell cycle progression, apoptosis, and the JAK2/STAT3 signaling pathway. LCH inhibited the growth of cells in dose- and time-dependent manners. The annexin V/propidium iodide double staining assay revealed that LCH induced apoptosis, and the LCH-induced apoptosis was accompanied by cell cycle arrest in the G1 phase. Western blot analysis showed that the phosphorylation of JAK2 and STAT3 was decreased by treatment with LCH. The inhibition of the JAK2/STAT3 signaling pathway by pharmacological inhibitors against JAK2/STAT3 (cryptotanshinone (CTS) and S3I-201) simulated the antiproliferative effect of LCH suggesting that LCH induced apoptosis by modulating JAK2/STAT3 signaling.