• 대한화장품학회지
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• 제44권3호
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• pp.285-293
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• 2018

코아세르베이트의 구조는 모발의 오일 및 폴리머 같은 기능성 성분 흡착에 매우 큰 영향을 준다. 본 연구의 목적은 알킬 셀룰로오스와 구아검 간 복합 코아세르베이트의 혼합물에서 그 구조적인 결합의 특성을 밝히는데 있다. 모발에 흡착되면 모발에 뻣뻣함을 부여하는 구아검 컨디셔닝 폴리머가 오일과 함께 알킬 셀룰로오스와 혼합될 경우 동일 함량 및 알킬 셀룰로오스와의 비가 3 : 1일 경우에 모발을 매우 부드럽게 함을 발견하였다. 이는 글루코스링을 백본으로 하는 양이온 알킬기 셀룰로오스 폴리머와 구아검 폴리머를 혼합하여 오일을 결합시키면, 알킬 셀룰로오스의 친수성 부위와 음이온 계면활성제가 정전기적으로 결합하고, 알킬 셀룰로오스의 4급 알킬 암모늄기에 포함되는 알킬기가 계면활성제의 소수성 부위와 함께 결합함과 동시에, 구아검 코아세르베이트가 전체적으로 안정적인 구조를 이루게 하여 많은 양의 코아세르베이트를 생성하게 하는 것을 코아세르베이트 생성양 측정 및 모발 유연성 증대를 통해 확인하였다.

• 에너지공학
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• 제18권2호
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• pp.75-86
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• 2009

본고는 한국 에너지 기업의 기술수준을 세계 최고수준과 대비하고, 이러한 기술수준을 결정하는 요인들을 기술경제이론과 경영자원의존이론을 통해 살펴보았다. 한국 에너지기업의 세계최고수준 대비 기술수준은 기술경제적 요인인 규모의 경제효과와 전방기업과 후방기업간 협력적 관계 등에 의해 긍정적 영향을 받고 있는 것으로 분석되었다. 반면, 국내시장의 경쟁정도, 연구개발투자 비중, 연구개발인력 비중 등은 국내 에너지기업의 세계 최고수준 대비 제품기술수준에 영향을 미치치 못하고 있는 것으로 분석되고 있다. 이 분석에서 얻을 수 있는 정책적 시사점은 한국 에너지기업의 기술수준을 제고하기 위해서는 국내시장을 더욱 경쟁적으로 전환해야 하며, 연구개발투자와 연구개발인력 등을 확충하고 부가가치사슬 상에서 전방기업과 후방기업 간 공동발전을 촉진하는 정책을 추진할 필요가 있다는 것이다.

• 한국컴퓨터그래픽스학회논문지
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• 제20권2호
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• pp.25-32
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• 2014

본 논문은 물리 시뮬레이션 환경에서 일련의 강체요소가 인과사슬에 따라 연쇄적으로 구동되는 가상의 루브 골드버그 기계를 합성하기 위한 예제 기반 접근방법을 제안한다. 일련의 요소 집합이 주어졌을 때, 본 논문의 목표는 사용자가 명시한 이동의 시작 및 종료위치, 그리고 경계 영역 조건을 만족하는 범위에서 이들 요소로만 구성된 루브 골드버그 기계를 자동으로 구축하는 것이다. 이를 위하여, 먼저 적은 개수의 요소로 구성된 소규모 컴포넌트들을 무작위로 추출한 후 모든 컴포넌트 쌍에 대한 결합 가능성을 하나의 그래프 구조로 표현한다. 이 그래프 위에서의 경로 탐색을 통하여 공간 상에 펼쳤을 때 사용자가 지정한 요구 조건을 만족시키는 경로를 찾고, 해당 경로에 따라 순차적으로 컴포넌트를 조립함으로써 기계를 구축한다. 완성된 기계가 물리 시뮬레이션 환경에서 정확히 동작함을 보장하기 위하여, 끝으로 간단한 그리디 알고리즘을 적용하여 조립된 컴포넌트들의 위치를 정교하게 조절한다. 다섯 종류의 요소만을 이용하여 만든 다양한 구조의 루브 골드버그 기계를 보임으로써 본 논문에서 제안한 방법의 유용성을 보인다.

• 전자공학회논문지S
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• 제36S권2호
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• pp.19-27
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• 1999

본 논문에서 입력 버퍼에 설정된 점유 임계치를 동적으로 가변 시켜 최대의 점유도를 갖는 포트를 우선적으로 서비스 하는 입력 버퍼형 ATM 스위치의 경합 제어 방식을 제안 하고 이것의 하드웨어적 실현 방안을 기술 한다. 하드웨어적 실현 방법은 고속화를 위해 단순 구조를 지향 하여 신호 경로단의 경감과 발열량의 절감을 추구 한다. 입력 버퍼에 설정되는 점유 임계치는 매 타임 슬롯 마다 셀의 입려과 경합 제어에 의한 셀의 서비스 결과를 기반으로 가장 점유도가 높은 버퍼가 경합 제어에서 가장 높은 우선권을 갖도록 동적으로 가변 된다. 제안한 경합 제어 방식의 특성을 분석 하기 위해 마코흐(Markov) 체인을 이용한 성능해석을 실시하고 다양한 트래픽 조건에서의 모사 시험을 통하여 제안된 방식과 기존의 방식간에 트래픽에 대한 적응성을 비교, 분석한다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권10호
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• pp.1386-1398
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• 2010

Soybean contains a high concentration of carbohydrates that consist mainly of non-starch polysaccharides (NSP) and oligosaccharides. The NSP can be divided into insoluble NSP (mainly cellulose) and soluble NSP (composed mainly of pectic polymers, which are partially soluble in water). Monogastric animals do not have the enzymes to hydrolyze these carbohydrates, and thus their digestion occurs by means of bacterial fermentation. The fermentation of soybean carbohydrates produces short chain fatty acids that can be used as an energy source by animals. The utilization efficiency of the carbohydrates is related to the chemical structure, the level of inclusion in the diet, species and age of the animal. In poultry, soluble NSP can increase digesta viscosity, reduce the digestibility of nutrients and depress growth performance. In growing pigs, these effects, in particular the effect on gut viscosity, are often not so obvious. However, in weaning piglets, it is reported that soy oligosaccharides and soluble NSP can cause detrimental effects on intestinal health. In monogastrics, consideration must be given to the anti-nutritive effect of the NSP on nutrient digestion and absorption on one hand, as well as the potential benefits or detriments of intestinal fermentation products to the host. This mirrors the needs for i) increasing efficiency of utilization of fibrous materials in monogastrics, and ii) the maintenance and improvement of animal health in antibiotic-free production systems, on the other hand. For example, ethanol/water extraction removes the low molecular weight carbohydrate fractions, such as the oligosaccharides and part of the soluble pectins, leaving behind the insoluble fraction of the NSP, which is devoid of anti-nutritive activities. The resultant product is a high quality soy protein concentrate. This paper presents the composition and chemical structures of carbohydrates present in soybeans and discusses their nutritive and anti-nutritive effects on digestion and absorption of nutrients in pigs and poultry.

• Asian Pacific Journal of Cancer Prevention
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• 제16권13호
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• pp.5371-5376
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• 2015

Berberine (B1), isolated from stems of Coscinium fenestratum (Goetgh.) Colebr, was used as a principle structure to synthesize three phenolic derivatives: berberrubine (B2) with a single phenolic group, berberrubine chloride (B3) as a chloride counter ion derivative, and 2,3,9,10-tetra-hydroxyberberine chloride (B4) with four phenolic groups, to investigate their direct and indirect antioxidant activities. For DPPH assay, compounds B4, B3, and B2 showed good direct antioxidant activity ($IC_{50}$ values=$10.7{\pm}1.76$, $55.2{\pm}2.24$, and $87.4{\pm}6.65{\mu}M$, respectively) whereas the $IC_{50}$ value of berberine was higher than $500{\mu}M$. Moreover, compound B4 exhibited a better DPPH scavenging activity than BHT as a standard antioxidant ($IC_{50}=72.7{\pm}7.22{\mu}M$) due to the ortho position of hydroxyl groups and its capacity to undergo intramolecular hydrogen bonding. For cytotoxicity assay against human fibrosarcoma cells (HT1080) using MTT reagent, the sequence of $IC_{50}$ value at 7-day treatment stated that B1 < B4 < B2 ($0.44{\pm}0.03$, $2.88{\pm}0.23$, and $6.05{\pm}0.64{\mu}M$, respectively). Berberine derivatives, B2 and B4, showed approximately the same level of CAT expression and significant up-regulation of SOD expression in a dose-dependent manner compared to berberine treatment for 7-day exposure using reverse transcription-polymerase chain reaction (RT-PCR) assays. Our findings show a better direct-antioxidant activity of the derivatives containing phenolic groups than berberine in a cell-free system. For cell-based system, berberine was able to exert better cytotoxic activity than its derivatives. Berberine derivatives containing a single and four phenolic groups showed improved up-regulation of SOD gene expression. Cytotoxic action might not be the main effect of berberine derivatives. Other pharmacological targets of these derivatives should be further investigated to confirm the medical benefit of phenolic groups introduced into the berberine molecule.

• Asian-Australasian Journal of Animal Sciences
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• 제28권5호
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• pp.686-690
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• 2015

The adrenergic receptor beta 2 (ADRB2) plays a role in various physiological responses of the muscle to exercise, such as contraction and relaxation. Given its important role in muscle function, we investigated the structure of the horse ADRB2 gene and its expression pattern after exercise to determine if it can serve as a putative biomarker for recovery. Evolutionary analyses using synonymous and non-synonymous mutation ratios, were compared with other species (human, chimpanzee, mouse, rat, cow, pig, chicken, dog, and cat), and revealed the occurrence of positive selection in the horse ADRB2 gene. In addition, expression analyses by quantitative polymerase chain reaction exhibited ubiquitous distribution of horse ADRB2 in various tissues including lung, skeletal muscle, kidney, thyroid, appendix, colon, spinal cord and heart, with the highest expression observed in the lung. The expression of ADRB2 in skeletal muscle was significantly up-regulated about four folds 30 minutes post-exercise compared to pre-exercise. The expression level of ADRB2 in leukocytes, which could be collected with convenience compared with other tissues in horse, increased until 60 min after exercise but decreased afterward until 120 min, suggesting the ADRB2 expression levels in leukocytes could be a useful biomarker to check the early recovery status of horse after exercise. In conclusion, we identified horse ADRB2 gene and analyzed expression profiles in various tissues. Additionally, analysis of ADBR2 gene expression in leukocytes could be a useful biomarker useful for evaluation of early recovery status after exercise in racing horses.

• 한국미생물·생명공학회지
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• 제24권1호
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• pp.19-26
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• 1996

A phospholipase C (PLC) inhibitor (MT267-2B) was isolated from the culture broth of actinomycetes isolate MT2617-2 by the extraction with n-butanol and column chromatographic techniques. The molecular weight of the inhibitor was 1057, by the spectroscopic analyses of IR, $^{13}C$-and $^{1}H$-NMR and ESI-MS. The chemical structure of MT2617-2B was found to be a macrolide compound consisted of a hemiketal ring, polyhydroxyl and polymethyl groups, which had a malonate and guanidine group as its side chain. MT2617-2B produced its two isomers having the same molecular weight by standing in methanol solution at room temperature. Therefore, MT2617-2B was identified as copiamycin and niphithricin A, macrolide antibiotics. The values of $IC_{50}$ against PLC-${\gamma}$1 and PLC-${\beta}$1 were 25 and 50${\mu}$g/ml, respectively. MT2617-2B had antimicrobial activities against Staphylococcus aureus and Candida albicans, but not against Escherichia coli.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.425.1-425.1
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• 2014

Thermal transport in nanomaterials is not only scientifically interesting but also technological important for various future electronic, bio, and energy device applications. Among the various computation approaches to investigate lattice thermal transport phenomena in nanoscale, the atomistic nonequilibrium Green's function approach based on first-principles density functional theory calculations appeared as a promising method given the continued miniaturization of devices and the difficulty of developing classical force constants for novel nanoscale interfaces. Among the nanometerials, carbon atomic chains, namely the cumulene (all-doulble bonds, ${\cdots}C=C=C=C{\cdots}$) and polyyne (alternation of single and triple bonds, ${\cdots}C{\equiv}C-C{\equiv}C{\cdots}$) can be considered as the extream cases of interconnction materials for nanodevices. After the discovery and realization of carbon atomic chains, their electronic transport properties have been widely studied. For the thermal transport properties, however, there have been few literatures for this simple linear chain system. In this work, we first report on the development of a non-equilibrium Green's function theory-based computational tool for atomistic thermal transport calculations of nanojunctions. Using the developed tool, we investigated phonon dispersion and transmission properties of polyethylene (${\cdots}CH2-CH2-CH2-CH2{\cdots}$) and polyene (${\cdots}CH-CH-CH-CH{\cdots}$) structures as well as the cumulene and polyyne. The resulting phonon dispersion from polyethylene and polyene showed agreement with previous results. Compared to the cumulene, the gap was found near the ${\Gamma}$ point of the phonon dispersion of polyyne as the prediction of Peierls distortion, and this feature was reflected in the phonon transmission of polyyne. We also investigated the range of interatomic force interactions with increase in the size of the simulation system to check the convergence criteria. Compared to polyethylene and polyene, polyyne and cumulene showed spatially long-ranged force interactions. This is reflected on the differences in phonon transport caused by the delicate differences in electronic structure.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.126-126
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• 2014

Label-free biomolecular assay based localized surface plasmon resonance (LSPR) of noble metal nanoparticles enables simple and rapid detection with the use of simple equipment. Nanosized metal nanoparticles exhibit a strong absorption band when the incident light frequency is resonant with the collective oscillation of the electrons, which is known as the LSPR. Here we demonstrate localized surface plasmon resonance (LSPR) substrates such as plasmonic Au nanodisks fabricated by a nanoimprinting process and gold nanorod-immobilized surfaces and their applications to highly sensitive and/or label-free biosensing. To increase detection sensitivity various bioreceptors weree designed. A single chain variable fragment (scFv) was used as a receptor to bind C-reactive protein (CRP). The results of this effort showed that CRP in human serum could be quantitatively detected lower than 1 ng/ml. Aptamers, which were immobilized on gold nanorods, were used to detect mycotoxins. The specific binding of ochratoxin A (OTA) to the aptamer was monitored by the longitudinal wavelength shift of LSPR peak in the UV-Vis spectra resulting from the changes of local refractive index near the GNR surface induced by accumulation of OTA and G-quadruplex structure formation of the aptamer. According to our results, OTA could be quantitatively detected lower than 1 nM level. Additionally, aptamer-functionalized GNR substrate was quite robust and can be regenerated many times by rinsing at 70 OC to remove bound target. During seven times of washing steps, the developed OTA sensing system could be reusable. Moreover, the proposed biosensor exhibited selectivity over other mycotoxins with an excellent recovery for detection in grinded corn samples, suggesting that the proposed LSPR based aptasensor plays an important role in label-free detection of mycotoxins.