• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.2
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• pp.77-127
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• 1999

활성 산소종은 노화, 특히 피부노화의 원인 물질로 작용하고 있다. 피부는 자외선에 노출되어 있어 활성 산소종을 만드는 광화학적 반응들이 계속해서 일어나고 있다. 이들 활성 산소종들은 피부 세포 및 조직 손상을 주도한다. 이들은 항산화 효소와 비효소적 항산화제들로 구성된 항산화 방어망을 파괴함으로써 산화제/항산화제 균형을 산화 상태 쪽으로 기울게 한다. 결과적으로 계속된 산화적 스트레스는 지질 과산화, 단백질 산화, 간질 성분을 파괴시키는 단백질분해효소의 활성화, 탄력 섬유인 콜라겐과 엘라스틴의 사슬절단 및 비정상적인 교차결합, 히아루론산 사슬의 절단, 멜라닌 생성반웅 촉진, DNA 산화와 같은 생체 구성 성분들의 손상을 야기시킨다. 결국에는 탄력감수 주름살 및 기미.주근깨 둥으로 특징 지워지는 피부노화가 가속화된다. 따라서 피부노화 방지를 위해서는, 과잉의 활성 산소종 생성을 억제하고 또한 생성된 활성산소를 효율적으로 제거할 수 있는 시스템이 화장품의 처방에 반드시 포함될 필요가 있다. 즉, 산화제/항산화제 밸런스가 유지되는 피부의 항산화 방어 시스템 구축이 필요하다. 피부노화 방지에 있어서 천연물의 역할로 (1) 자외선 흡수제로서의 역할, (2) 항산화제로서의 역할, (3) 주름 개선제로서의 역할, (4) 미백제로서의 역할, (5) 항균\ulcorner항염작용 및면역 조절제로서의 역할에 대하여 살펴 보았다. 21세기는 본격적으로 기능성 화장품 시대가 개막될 것으로 예측하고 있다. 이에 맞춰 천연물들은 피부노화를 방지하는데 주도적인 역할을 할 것으로 기대된다.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.1
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• pp.61-86
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• 2022

This paper analyzes the technology transfer mechanism of companies clustered in a specific economic space from the perspective of absorptive capacity, taking the Daegu automotive parts industry as an example. According to the analysis results, The absorptive capacity of a company was found to be positively related to the supplier, channel, method, and institutional interaction of technology transfer. Low absorptive capacity limits technology transfer by reducing companies' technology search capabilities, while high absorptive capacity gives companies access to technology search and various technology transfer opportunities through formal and informal channels. These results suggest that, in the short term, it is necessary to supplement the search capabilities of companies through preemptive visiting services of local intermediaries for the vitalization of regional technology transfer, while in the long term, a policy approach focusing on enhancing the absorptive capacity of local companies is required. For effective implementation of these policies, a multi-layered governance approach corresponding to each level of companies' absorptive capacities is required in establishing an interface structure that promotes linkage between institutional actors.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.133-139
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• 1974

The objective of this study is to compare the effects of raw materials as method of speeding up mounting of matured silkworm, for reducing concentrated labor during mounting periods. The results obtained from this study are summarized as fellows： (1) Quercus acutissima Carrs showed the most remarkable effect of repellent. Persicaria blumei Gross and Artemisia asiatica Nakai were followed in order. The rest repellents were also expected to be applicable. considering known material (silk-up) with lower mounting percentage. (2) The effective methods of preparation of repellent were to make distillate. Decocted solution type was considered to be the easiest way of preparation. (3) It seemed to be that there was little effect of repellent on the qualities of cocoon and silk. (4) When a repellent was applied to a silkworm bed, immatured silkworms were observed to mount. Thus it suggests that the repellent will give remarkable effects only when the degree of matured of silkworms is uniform.

• Clean Technology
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• v.20 no.4
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• pp.383-389
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• 2014

$CO_2$ absorption processes have a good potential for large scale capture of $CO_2$ but a large amount of absorbing solution has to be regenerated, undesirably increasing the consumption of energy such as sensible heat and latent heat of vaporization. In this study, a cooling crystallization process which would separate the $CO_2$-rich potassium bicarbonate crystals from $CO_2$-lean water was developed to reduce the energy penalty. Sterically hindered alkanolamine additives were used to enhance the $CO_2$ removal efficiency and their antisolvent effect on the crystallization was found in a continuous cooling crystallizer. The production yields of crystals were increased in the sequence of 2-amino-2-methyl-1-propanol (AMP) < 2-amino-2-methyl-1,3-propanediol (AMPD) < 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), which are related to the number of hydroxyl groups in the additive molecules. Using $^{13}carbon$ nuclear magnetic resonance, the additives favored the formation of bicarbonate ions by steric hindrance effect and increased the supersaturation of $KHCO_3$. It is shown that the additives increase the mean size of crystals and crystal growth rate by increasing supersaturation. The additives are promising for enhancing the $CO_2$ removal efficiency and reducing the regeneration energy cost of $CO_2$ absorbing solution by promoting $KHCO_3$ crystallization.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.129-134
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• 2003

A wide variety of unsaturated vinyl derivatives can be induced to undergo free-radical chain polymerization. The capability to carry out a thermodynamically feasible polymerization relies on its kinetic feasibility on whether the proceeds at a reasonable rate under a given set of reaction conditions. Initiator or promoter is often required to achieve the kinetic feasibility. Only a few unsaturated monomers including methyl methacrylate(MMA) are known to absorb light between 250 and 500 nm which is the most convenient wavelength range. Also, the polysilanes with unusual optical and electronic properties have been used as ceramic precursors, deep UV photoresists, photoconductors. The hydrosilation has been used to make many interesting types of silicon containing polymers such as copolymer, dendrimers. Bulk polymerization of monomers with different molar radio of hydrosilanes(9:1 through 1:9) were performed. A quartz test tube charged with monomer and hydrosilane was degassed and irradiated with 250 nm UV for 6 hours. The polymer was taken in toluene, precipitated in hexane, filtered off, and dried. It was found that the initiators appeared to competitively and concurrently function as both chain initiation and transfer agents in the polymerization of vinyl monomers.

• Membrane Journal
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• v.10 no.1
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• pp.39-46
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• 2000

To predict the absorption behavior of carbon dioxide on membrane contactor, an aqueous potassium carbonate solution as an absorbent. The reversible reactions of carbon dioxide with chemicals were considered, and the physicochemical properties of reaction rate constants, equilibrium constants, solubilities and diffusion coefficients were used as a function of concentration of carbon dioxide and the temperature. A non-wetted mode was also used as an operating condition of the membrane contactor. In these operation conditions, the effect of the following system parameters were studied : the concentration of potassium carbonate, the velocity of the absorbent and the pressure of the mixture gas. The absorption behavior of carbon dioxide caused by a facilitated transport was observed as the increment of the concentration of the absorbent. The absorption rate of carbon dioxide was increased as the absorbent velocity was increased. Furthermore, it was found that the pressure if the mixture gas and the reuse number of absorbent affect severely the absorption rate of carbon dioxide. The absorption behavior was successfully predicted by the computer simulation using the system parameters which are important for design and operation of the membrane contactor.

• YAKHAK HOEJI
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• v.38 no.4
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• pp.440-450
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• 1994

Due to the limited bioavailability of $[D-Ala^6]$LHRH from nonparenteral transmucosal sites of administration, enhancement of mucosal permeability by coadministration of several protease inhibitors and/or penetration enhancers were studied in rabbit mucosa. As a reliable bioassay method for $[D-Ala^6]$LHRH, ovulation-inducing effect were measured after vaginal administration in the rat. The permeation of $[D-Ala^6]$LHRH through the mucosal membrane of rabbit mounted on George-Grass diffusion cells were examined in the presence of polyoxyethylene 9-lauryl ether (POE), ${\beta}$-cyclodextrin$({\beta}-CyD)$ or ethylene diamine tetra acetate disodium salt(EDTA). The vaginal membrane showed higher permeability of $[D-Ala^6]$LHRH than the rectal and nasal membrane. POE and ${\beta}-CyD$ showed a small promoting effect on the membrane permeation of $[D-Ala^6]$LHRH, but EDTA showed significant enhancement. Ovaluation was enhanced by the coadministration of sodium laurate(0.5%), a protease inhibitor but was not enhanced by EDTA, a penetration enhancer. On the other hands, coadministration of sodium tauro 24,25 dihydrofusidate(1%) and EDTA(2%) enhanced the ovulation inducing-effect 2.8 times. These results suggest that the vaginal administration of $[D-Ala^6]$LHRH with STDHF or sodium laurate as a protease inhibitor, and EDTA as a penetration enhancer, may become an elective method for transmucosal delivery of $[D-Ala^6]$ LHRH.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.5
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• pp.604-611
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• 2003

This study was concerned with the enhancement of mass transfer by surfactant added to the aqueous solution of LiBr. Different vertical inner tubes were tested with and without an additive of normal octyl alcohol. The test tubes were a bare tube, groove tube, corrugate tube and inserted spring tubes. The additive concentration of normal octyl alcohol as a surfactant is about 0.08mass%. The Sherwood number was measured as a function of film Reynolds number 20~200. The experimental results were compared with those which use no surfactant. The enhancement of mass transfer by Marangoni convection effect which was generated by addition of the surfactant is proved for each testing tube Especially, it is clarified that the tube with the spring has the highest enhancement effect. A correlation of the experimental mass transfer data for the bare, groove, corrugate and insert spring tubes results expressed as the form of Sh=cㆍ Re$_{f}$ $^{n}$ .

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.92-95
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• 2001

고분자 복합체 절연재료는 porcelain 이나 glass 같은 세라믹 소재의 재료와 비교하여 옥외사용 시간의 관점에서 더 뛰어난 특정을 발휘한다. 그러나 노화되었을 때, 이들 옥외용 절연재료의 성질은 발수성이나 흡수성등과 같은 절연재료의 표면특성에 의해 변화한다. 이러한 표면특성의 변화는 누설전류에 의한 트래킹 (tracking), 침식 (erosion) 및 섬락현상(flashover) 등의 유전체 파괴에 이르게 한다. 본 연구에서는 고분자 복합체 절연재료로 널리 이용되고 있는 EPDM의 발수특성을 향상시키기 위해 기존에 이용되던 무기물 첨가제인 alumina hydrate(ATH)이외에 발수성이 뛰어난 실리콘 고무를 상용화제를 이용하여 블렌드하고, 각종 유기 첨가제 및 무기물 보강제를 이용하여 EPDM/Silicone 복합체를 제조하였다. EPDM/Silicone 복합체의 인장강도 및 유전강도는 실리콘의 함량이 증가할수록 낮아졌으며, 촉진 노화시험을 실시한 결과 $120^{\circ}C$까지 인장강도 및 신율을 유지하였다. 유전강도의 측정결과 복합체의 접촉각과 표면에너지 측정결과 Silicone 고무의 함량이 증가할수록 접촉각은 증가하고, 표면에너지는 낮아졌다. 경사평판법에의한 내트래킹성 측정결과 실리콘 함량이 증가할수록 내트래킹성은 우수하였으며, 실리콘 함량이 30%인 복합체에서는 트래킹 및 침식이 진행되지 않았다.

• Journal of Life Science
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• v.31 no.8
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• pp.729-735
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• 2021

Type 2 diabetes occurs when there is an abnormality in the tissue's ability to absorb glucose. Glucose uptake and metabolism by insulin are the basic mechanisms that maintain blood sugar. Glucose uptake goes through various signaling steps initiated by the binding of insulin to receptors on the cell surface. In line with the foregoing, the purpose of this study was to investigate the effect of 2,7-phloroglucinol-6,6-bieckol (PHB), an active compound isolated from Ecklonia cava, on glucose uptake in 3T3-L1 adipocytes. Notably, PHB increased glucose uptake in a dose-dependent manner owing to the enhanced glucose transporter type 4 (GLUT4) expression in the plasma membrane of 3T3-L1 adipocytes. These effects of PHB were attributed to the phosphorylation of insulin receptor substrate-1 and protein kinase B (PKB or AKT), as well as to the phosphoinositide 3-kinase (PI3K) activation in the insulin signaling pathway. PHB also stimulated 5' AMP-activated protein kinase (AMPK) phosphorylation and activation. The phosphorylation and activation of the PI3K/AKT and AMPK pathways by PHB were identified using wortmannin (a PI3K inhibitor) and compound C (an AMPK inhibitor). In this study, we showed that PHB can increase glucose uptake in 3T3-L1 adipocytes by promoting GLUT4 translocation to the plasma membrane via the PI3K and AMPK pathways. The results indicate that PHB may help improve insulin sensitivity.