• Biomolecules & Therapeutics
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• 제22권4호
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• pp.301-307
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• 2014

Fucodiphlorethol G (6'-[2,4-dihydroxy-6-(2,4,6-trihydroxyphenoxy)phenoxy]biphenyl-2,2',4,4',6-pentol) is a compound purified from Ecklonia cava, a brown alga that is widely distributed offshore of Jeju Island. This study investigated the protective effects of fucodiphlorethol G against oxidative damage-mediated apoptosis induced by ultraviolet B (UVB) irradiation. Fucodiphlorethol G attenuated the generation of 2, 2-diphenyl-1-picrylhydrazyl radicals and intracellular reactive oxygen species in response to UVB irradiation. Fucodiphlorethol G suppressed the inhibition of human keratinocyte growth by UVB irradiation. Additionally, the wavelength of light absorbed by fucodiphlorethol G was close to the UVB spectrum. Fucodiphlorethol G reduced UVB radiation-induced 8-isoprostane generation and DNA fragmentation in human keratinocytes. Moreover, fucodiphlorethol G reduced UVB radiation-induced loss of mitochondrial membrane potential, generation of apoptotic cells, and active caspase-9 expression. Taken together, fucodiphlorethol G protected human keratinocytes against UVB radiation-induced cell damage and apoptosis by absorbing UVB radiation and scavenging reactive oxygen species.

• 생명과학회지
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• 제21권8호
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• pp.1100-1108
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• 2011

흰쥐에서 내독소로 유도된 급성 폐손상에서 moxifloxacin의 효과를 형태학적으로 호중구의 폐장 내 침윤 및 세포질형 포스포리파아제(cytosolic phospholipase A2) 발현과 관련하여 알아보았다. 내독소는 잘 알려진대로 흰쥐에서 급성 폐손상을 유발하였고 이때 폐장 내의 호중구의 침윤 및 폐장 및 호중구에서의 세포질형 포스포리파아제의 발현이 증가하였고, 또한 염증성 사이토카인의 일종인 종양괴사성인자(tumor necrosis factor)의 발현도 증가하였다. 전자현미경을 이용한 산소기 생성의 검사에서도 내독소에 의하여 산소기의 생성이 폐장 내에 증가한 사실을 확인하였고, 산화성 스트레스에 유발되는 제2형 폐포세포에서의 층상체의 변화도 관찰하였다. 면역변환효과가 있다고 알려진 moxifloxacin은 이러한 변화들을 억제하고 형태학적으로 내독소에 의한 급성 폐손상을 현저히 감소시켰다.

• 한국작물학회지
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• 제49권1호
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• pp.12-18
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• 2004

Activity of senescence-induced antioxidant enzymes in the detached rice seedlings (Oryza sativa L. cv. Dongjin) was examined. The levels of $\textrm{H}_2\textrm{O}_2$ content and peroxidase (POD) activity were gradually increased during leaf senescence, whereas catalase activity was decreased. The activity of superoxide dismutase (SOD) was increased, and ascorbate peroxidase (APX) and glutathione reductase (GR) were slightly increased until 3d and 4d of dark induced-senescence, and thereafter were decreased. The activation of all SOD isoforms showed a significant decrease after 6d and 7d. After 4d to 7d of dark senescence, there was a significant effect in enhancing the activity of APX-12 and -13 isoforms as compared with light, despite similar levels in total APX activity. GR-8 and -10 isoforms were more effective in leaf senescence at 4d to 7d, particularly with respect to dark-induced senescence. These results suggest that the metabolism of active oxygen species such as $\textrm{H}_2\textrm{O}_2$ is dependent on various functionally interrelated antioxidant enzymes such as catalase, peroxidase, SOD, APX and GR.

• 한국환경농학회지
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• 제23권3호
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• pp.128-132
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• 2004

공시된 세 품종의 고추에 대한 단기간의 오존 처리로 잎에서 나타나는 전형적인 증상은 갈색의 괴사 반응이었으며, 괴사가 심했던 오존 감수성인 다보탑과 같은 농도에서 괴사가 전혀 없었던 부촌 품종을 오존 저항성 품종으로 판단되었다. 고추의 두 품종에서 오존 처리에 의해 광합성 및 기공 전도도 등의 생리생태적 저해가 뚜렷이 나타났다. 그러나 잎에서 가시피해의 정도와 생리생태적 저해 정도와의 상호 연관성으로 고추에서의 오존 저항성 기작을 설명하고자 하였으나 생리생태적 반응으로 잎에서 발생하는 오존 저항성의 기작을 설명할 수 없었다. 다만, 고추에서 오존 처리에 의한 광합성 감소는 뚜렷한 기공전도도 감소와 명반응에서 광합성 기구들의 손상에 기인한다고 여겨진다. 그러나, 암반응에서 생화학적 반응을 설명할 수 있는 A-Ci curve 상에서는 오존 처리에 따른 효과를 찾을 수 없었다.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
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• pp.27-39
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• 2005

a-Ketol linolenic acid [KODA, 9,10-ketol-octadecadienoic acid, or 9-hydroxy-10 -oxo-12(Z), 15(Z)-octadecadienoic acid] was found as a stress-induced factor in Lemna paucicostata. KODA reacts with catecholamines to generate many products that strongly induce flowering in L. paucicostata, although KODA itself was inactive. KODA contains an asymmetric carbon at the 9-position in the molecule; the 9-hydroxyl group is predominantly 9R, with an enantiomeric excess of 40% (70% 9R and 30% 9S). We analyzed two major products of the reaction between KODA and norepinephrine, named FN1 and FN2. FN1 was identified as a tricyclic a-ketol fatty acid, 9(R)-11-{(2'R,8’R,10'S,11'S)-2',8'-dihydroxy-7'-oxo-11'-[(Z)-2-pentenyl]-9'-oxa-4'-azatricyclo[6.3.1.01.5]dodec-5'en-10'-yl}-9-hydroxy-10-oxoundecanoic acid. FN2 was the C-9 epimer of FN1. FN1 was derived from 9R-type KODA and FN2 from 9S-type. FN1 showed strong flower-inducing activity, but FN2 was inactive. Pharbitis nil (violet) is a typical short-day plant; flowering can be induced by exposing a seedling cultivated under continuous light to a single 16-h dark period. We analyzed endogenous KODA levels and showed that they were closely related to flower induction: KODA sharply increased in the later part of a 16-h dark period, on the other hand, it failed to increase in the night-break experiment. In addition to it, KODA increased transiently in immature flower buds in all the plants we examined, including P. nil. No such increase of KODA was seen in foliar buds of P. nil. When KODA was sprayed on seedlings of Pharbitis, flower induction was promoted only by the (R)-form of KODA. We also found that KODA enhances flowering in garden plants such as carnations and impatienses. These phenomena indicate that KODA may be involved in flowering formationg of plants and it is potentially useful for a regulating agent for commercial plant flowering.

• 한국정밀공학회지
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• 제22권11호
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• pp.45-50
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• 2005

In this study, the casting/forging process was applied in manufacturing a low control arm, in order to prove that application of casting/forging process to Al6061 is likely to get the effect of light weight compared with existing steel products and to reduce the cost of materials. Firstly, In order to set up the optimum casting condition of the forging material, Al6061, casting experiments were carried out by controlling pouring temperature of the aluminum for casting, mold temperature, and pouring time. $700^{\circ}C$ pouring temperature, $300^{\circ}C$ mold temperature and 10-second pouring time were taken into account as the optimum casting conditions. With respect to a hot forging test, it is practiced on the basis of a temperature of materials, strain rate, and reduction rate so as to observe each microstructure and examine strain-stress curve simultaneously; examine tensile test and hardness test; eventually set up the optimum hot forging condition. A hot forging test, tensile test, hardness experiment, and microstructure observation were carried out on condition of $70\%$ reduction rate, $500^{\circ}C$ temperature of materials, and 1 strain rate. As a result of those experiments, 330MPa tensile strength, $16.4\%$ elongation, and 122.8Hv hardness were recorded. In oder to get a sound preform which has no unfitting cavity and less flash, two preforms were proposed on the basis of volume rate of the final product; the optimum volume rate of preform for the low control arm was $115\%$. In conclusion, it is confirmed that using the forging material rather than casting materials in casting/forging process is likely to get more superior mechanical properties. Compared with Al6061, performed by means of general forging, moreover, cast/forged Al6061 can not only stimulate productivity by reducing production processes, but cut down the cost of materials by reusing forging scraps.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 제5회 압출 및 인발가공 심포지엄
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• pp.43-49
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• 2002

A7003 alloy has characteristics of their excellent weldability, high corrosion resistance and superior plastic working however the broadening of application for the alloy has been hampered by the lower extrudability associated by Mg content. For improvement of extrudability and enhanced recovery efficiency during Al scrap recyeling, it has been generally practiced to reduce Mg content in A7003 alloy. Therefore, it is necessary to investigate the influence of Mg content on mechanical strength and extrudability of A7003 alloy. For efficient material processing which has small amounts, life cycle assessment in material processing(MLCA) is evaluated. The quantitative analysis of energy requirements and $CO_2$ emission for production of A7003 extruded bar are estimated with different Mg content and billet pre-heating process (heating source by light oil or LPG). In particular, the estimation of energy requirements was performed within shipping and gating range (except the mining and extraction stages)to investigate the influence of the variables on energy requirements and $CO_2$ emission in detail. As Mg content increased, the flow stress and the extrusion pressure for A7003 alloy increased. It has been thought that an increment in extrusion pressure with increasing Mg content is caused by the solid solution hardening of Mg atoms in the matrix and increment in volume fraction of intermetallic compound, $Mg_2Si$. The extrudability and the tensile strength are equal to, or above that of conventional A 7003 alloy even the content of Mg varied from $1.1wt.\%\;to\;0.5wt.\%$ alloy. This means that minimizing the content of Mg in A7003 alloy can enhance recovery efficiency during Al scrap recycling. It can be quoted that rather than Mg content energy source for billet heating is a prime factor to determine the atmospheric $CO_2$ emission.

• 한국강구조학회 논문집
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• 제23권1호
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• pp.125-135
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• 2011

최근 타워형 아파트구조에 많이 사용되고 있는 무량판 구조시스템을 대신해 층고절감 및 장스팬 구현 그리고 내화성능향상을 목적으로 GFRP를 이용한 경량합성바닥을 개발하였다. GFRP를 이용한 경량합성바닥은 웨브에 개구부를 가지는 비대칭 강재보 하부에 GFRP를 부착하고 슬래브에 경량체를 삽입한 중공합성바닥이다. 이에 개발된 합성바닥의 휨성능을 평가하기 위해 GFRP, 중공률, 웨브의 개구부 등을 변수로 실대 실험을 수행하였다. 그 결과 GFRP를 이용한 합성보 실험체는 기준 실험체에 비해 휨내력 및 강성 측면에서 10% 높은 성능을 나타냈으며, 구조물이 항복할 때까지 완전합성거동하였다. 항복 이후 웨브개구부 주변의 응력집중현상에 의해 연성이 감소하는 현상이 나타났으며, 최대내력점까지 미끄러짐의 발생은 미소하였다. 내력설계 측면에서는 안전율을 고려해 해석값의 85%를 설계내력으로 평가하는 것이 타당한 것으로 나타났다.

• 한국환경과학회지
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• 제14권3호
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• pp.345-350
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• 2005

Three-week old Commelina communis was transferred and grown in Hoagland solution containing $100{\mu}M\;Cd^{2+},\;100{\mu}M\;Cd^{2+}+100{\mu}M\;kinetin,\;100{\mu}M\;Cd^{2+}+100{\mu}M\;zeatin\;and\;100{\mu}M\;Cd^{2+},\;200{\mu}M$ zeatin for 7 days, and then a number of physiological activities were investigated. In control, the length of the stem of plants was increased to 4.7cm, but in $Cd^{2+},\;Cd^{2+}+kinetin,\; Cd^{2+}+100{\mu}M\;zeatin\;and\;Cd^{2+}+200{\mu}M$ zeatin treatments, the growth of plants were increased to 1.5cm, 2.1cm, 3.9cm and 4.3 em, respectively. In the treatments of $Cd^{2+},\;Cd^{2+}+kinetin,\;Cd^{2+}+100{\mu}M\;zeatin\;and\; Cd^{2+}+200{\mu}M$ zeatin, total chlorophyll contents were reduced to $26\%,\;24\%,\;15\%\;and\;3\%$, respectively, on the contrast to the control. In chlorophyll fluorescence experiments, Fv/Fm ratios were also reduced to $44\%,\;21\%,\;17\%\;and\;5\%$ in the light intensity of $2100{\mu}Mmole\;E\;m^{-2}s^{-1}\;by\;Cd^{2+},\;Cd^{2+}+kinetin,\;Cd^{2+}+$100{\mu}M\;zeatin\;and\;Cd^{2+}+200{\mu}M$ zeatin treatments on the contrast to the control. Water stresses were increased to 2.6, 1.7 and 1.2 times by $Cd^{2+},\; Cd^{2+}+kinetin\;and\;Cd^{2+}+{\mu}M$ zeatin. On the other hand, combination of $Cd^{2+}+200{\mu}M$ zeatin reduced water stress to $0.12\%$. In $Cd^{2+}$ accumulation experiments $Cd^{2+}$transports were inhibited to $33\%\; 48\%\;and\;70\%\;by\;Cd^{2+}+kinetin,\;Cd^{2+}+100{\mu}M\;zeatin\;and\;Cd^{2+}+200{\mu}M$ zeatin. Therefore, it could be concluded that zeatin clearly reduced the toxicities of $Cd^{2+}$ by reducing the absorption of $Cd^{2+}$.

• Asian Pacific Journal of Cancer Prevention
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• 제17권4호
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• pp.1967-1971
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• 2016

Background: In tumor cells, aberrant differentiation programs have been described. Several neuronal proteins have been found associated with morphological neuronal-glial changes in breast cancer (BCa). These neuronal proteins have been related to mechanisms that are involved in carcinogenesis; however, this regulation is not well understood. Microtubule-associated protein-tau (MAP-Tau) has been describing in BCa but not its variants. This finding could partly explain the neuronal-glial morphology of BCa cells. Our aim was to determine mRNA expression of MAP-tau variants 2, 4 and 6 in breast cancer cell lines. Materials and Methods: Cultured cell lines MCF-10A, MDA-MB-231, SKBR3 and T47D were observed under phase-contrast microscopy for neural morphology and analyzed for gene expression of MAP-Tau transcript variants 2, 4 and 6 by real-time PCR. Results: Regarding morphology like neural/glial cells, T47D line shown more cells with these features than MDA-MB-231 and SKBR. In another hand, we found much greater mRNA expression of MAP-Tau transcript variants 2, and to a lesser extent 4 and 6, in T47D cells than the other lines. In conclusion, regulation of MAP-Tau could bring about changes in cytoskeleton, cell morphology and motility; these findings cast further light on neuronal transdifferentiation in BCa.