• Journal of Radiation Protection and Research
• /
• 제36권3호
• /
• pp.119-126
• /
• 2011

Mitochondrial DNA (mtDNA) deletion is a well-known marker for oxidative stress and aging, and contributes to harmful effects in cultured cells and animal tissues. mtDNA biogenesis genes (NRF-1, TFAM) are essential for the maintenance of mtDNA, as well as the transcription and replication of mitochondrial genomes. Considering that oxidative stress is known to affect mitochondrial biogenesis, we hypothesized that ionizing radiation (IR)-induced reactive oxygen species (ROS) causes mtDNA deletion by modulating the mitochondrial biogenesis, thereby leading to cellular senescence. Therefore, we examined the effects of IR on ROS levels, cellular senescence, mitochondrial biogenesis, and mtDNA deletion in IMR-90 human lung fibroblast cells. Young IMR-90 cells at population doubling (PD) 39 were irradiated at 4 or 8 Gy. Old cells at PD55, and H2O2-treated young cells at PD 39, were compared as a positive control. The IR increased the intracellular ROS level, senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal) activity, and mtDNA common deletion (4977 bp), and it decreased the mRNA expression of NRF-1 and TFAM in IMR-90 cells. Similar results were also observed in old cells (PD 55) and $H_2O_2$-treated young cells. To confirm that a increase in ROS level is essential for mtDNA deletion and changes of mitochondrial biogenesis in irradiated cells, the effects of N-acetylcysteine (NAC) were examined. In irradiated and $H_2O_2$-treated cells, 5 mM NAC significantly attenuated the increases of ROS, mtDNA deletion, and SA-${\beta}$-gal activity, and recovered from decreased expressions of NRF-1 and TFAM mRNA. These results suggest that ROS is a key cause of IR-induced mtDNA deletion, and the suppression of the mitochondrial biogenesis gene may mediate this process.

• 한국미생물·생명공학회지
• /
• 제17권2호
• /
• pp.126-130
• /
• 1989

인삼 saponin 중에서 조성 비율이 가장 큰 ginsenoside R $b_1$을 약효면에서 훨씬 우수한 ginsenoside-Rd로 선택적 전환할 수 있는 전환효소를 Rhizopus japonicus 배양물로부터 순수하게 정제한 후 그 효소학적 특성을 조사하였다. 본 효소는 pH 4.8~5.0, 45$^{\circ}C$에서 그 활성도가 가장 높았으며 pH4~9의 범위에서 안정하였고, pH5.0에서 6$0^{\circ}C$ 열처리할 경우 50% 실활하는데 2시간이 소요되었다. M $n^{++}$, F $e^{++}$에 의해 효소활성이 촉진되었으며 C $u^{++}$, A $g^+$에 의해서는 저해되었다. 효소 저해제중에는 EDTA, o-phenanthroline 등에 의해 저해되기도 했다. 본 효소는 당류중에는 gentiobiose, cellulose만을, glycoside 중에서는 amygdalin, purnasin, salicin 등을 분해할 수 있었으며 ginsenoside R $b_1$, 이외의 다른 ginsenoside는 전혀 분해할 수 없었다. 본 효소의 Km치는 total saponin 기질 및 ginsenoside Rb group saponin 기질은 ginsenoside R $b_1$으로서 5.0mM 이었으며, gentiobiose는 4.8mM, amygdalin은 3.7mM 이었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제36권5호
• /
• pp.366-374
• /
• 2010

Introduction: This study evaluated the capability of silk fibroin (SF) and recombinant human bone morphogenetic protein-2 loaded SF (SF-BMP) as a bone defect replacement matrix when grafted in a calvarial bone defect of rats in vivo. Materials and Methods: A total 70 calvarial critical size defects (5.0 mm in diameter) made on 35 adult female Sprague-Dawley rats were used in this study. The defects were transplanted with (1) rhBMP-2 loaded silk fibroin graft (SF-BMP: 0.8+$10\;{\mu}g$), (2) Silk fibroin (SF: $10\;{\mu}g$), and (3) no graft material (Raw). The samples were evaluated with soft x-rays, alkaline phosphatase activity, calcium/phosphate quantification, histological and histomorphometric analysis at postoperative 4 and 8 weeks. Results: The SF-BMP group ($48.86{\pm}14.92%$) had a significantly higher mean percentage bone area than the SF group ($24.96{\pm}11.01%$) at postoperative 4 weeks.(P<0.05) In addition, the SF-BMP group ($40.01{\pm}12.43%$) had a higher % bone area at postoperative 8 weeks than the SF group ($33.26{\pm}5.15%$). The mean ratio of gray scale levels to the host bone showed that the SF-BMP group ($0.67{\pm}0.08$) had a higher mean ratio level than the SF group ($0.61{\pm}0.09$) at postoperative 8 weeks. These differences were not statistically significant.(P=0.168 and P=0.243, respectively) The ratio of the calcium and phosphate contents of the SF-BMP ($0.93{\pm}0.22$) group was lower than that of the SF ($1.90{\pm}1.42$) group at postoperative 4 weeks. However, the SF-BMP group ($0.75{\pm}0.31$) had a higher Ca/$PO_4$ ratio than the SF ($0.68{\pm}0.04$) at postoperative 8 weeks. These differences were not statistically significant.(P=0.126 and P=0.627, respectively) For the bone-specific alkaline phosphatase (ALP) activity, which is recognized as a reliable indicator of the osteoblast function, the SF-BMP ($23.71{\pm}8.60\;U/L$) groups had a significantly higher value than the SF group ($12.65{\pm}6.47\;U/L$) at postoperative 4 weeks.(P<0.05) At postoperative 8 weeks, the SF-BMP ($21.65{\pm}10.02\;U/L$) group had a lower bone-specific ALP activity than the SF group ($16.72{\pm}7.35\;U/L$). This difference was not statistically significant.(P=0.263) For the histological evaluation, the SF-BMP group revealed less inflammation, lower foreign body reactions and higher bone healing than the SF group at postoperative 4 and 8 weeks. The SF group revealed more foreign body reactions at postoperative 4 weeks. However, this immunogenic reaction decreased and the remnant of grafted material was observed at postoperative 8 weeks. For histomorphometric analysis, the SF-BMP group had a significantly longer bone length to total length ratio than those of the SF group at postoperative 4 and 8 weeks.(P<0.05) Conclusion: The rhBMP-2 loaded silk fibroin graft revealed fewer immunoreactions and inflammation as well as more new bone formation than the pure silk fibroin graft. Therefore, silk fibroin may be a candidate scaffold for tissue engineered bone regeneration.

• 한국환경농학회지
• /
• 제18권3호
• /
• pp.292-297
• /
• 1999

수중에서 유기합성화합물의 oxidative coupling을 통한 제거에 촉매제로서 식물체의 직접적인 이용 가능성을 검토하기 위하여 제지, 염료 및 전자회사 등에서 배출되고 있는 phenol성 화합물인 2,4-DCP를 이용하였다. 이 제거반응은 식물체에 포함된 산화환원효소에 의해 매개되어지는 oxidative coupling반응에 의해 유기독성화합물들간의 중합 반응으로 생성된 polymer가 침전됨으로서 야기되었다. 여러식물체들을 선별하여 이들 식물체가 가지고 있는 peroxidase의 활성을 측정한 결과 냉이에서 가장 높은 peroxidase의 활성이 관찰되었고 순무, 고구마, 배추 그리고 무 뿌리의 순이었다. Peroxidase의 활성이 비교적 높은 것으로 나타난 순무와 냉이를 이용해 다양한 실험조건하에서 2,4-DCP의 제거정도를 조사한 결과 2,4-DCP의 최대제거는 냉이의 경우 3분 이내, 순무의 경우 15분 이내로 아주 신속하게 이루어졌으며, 실험을 수행한 pH 전 범위(pH 3.0-8.0)에서 높은 제거율(90% 이상)을 유지하였다. 전자수용체로 작용하는 hydrogen peroxide를 9mM 첨가하였을 때 최대 제거율을 보였으며, 그 농도를 증가시키더라도 제거율은 더 이상 증가되지 않았다. 초기농도를 달리하여 냉이와 순무에 의한 2,4-DCP의 제거율을 조사한 결과 냉이로 매개된 2,4-DCP의 제거율은 초기농도 1,600ppm까지 90% 이상의 제거율을 나타내었으나, 순무로 매개된 2,4-DCP의 경우 초기농도 1,200ppm까지 90%이상의 제거율을 나타내다가 초기농도가 1,600ppm로 증가되었을 때 78.8%로 제거율이 감소되어 유기독성물질의 초기농도는 식물체를 이용한 유기독성물질의 제거에 약간의 영향을 미치는 것으로 나타났다.

• 한국환경과학회지
• /
• 제13권3호
• /
• pp.205-214
• /
• 2004

This study focuses on the measurement of airborne Volatile Organic Compounds (VOCs) in the Kumi electronic industrial complex during the time periods of August and September, 2002 and January and February, 2003. This study was based on the US-EPA method TO-14 while the VOCs were analyzed with GC/MSD. The toluene level revealed high concentration at all measurement sites. The areal rank of average concentrations of VOCs is as follows: industry1 > industry2 > urban > middle > residential. Concentrations of VOCs in Kumi electronic industrial ones were generally higher than at Yeochon and Ulsan industrial complexes. Dichloromethane and trichloroethylene, which are used as a cleaner in the process of electronic industries, were observed 4 to 8 times higher than those of other areas. Among the aromatic compounds, toluene showed the highest level, while the concentrations of dichloromethane and trichloroethylene were higher than those of other halogen compounds. In Kumi, toluene, trichloroethylene, and dichloromethane were confirmed as the major compounds of VOCs by this research.

• 대한한의학방제학회지
• /
• 제8권1호
• /
• pp.319-328
• /
• 2000

To evaluate the effect of Baepungtang(BPT) water extract on cultured mouse spinal sensory neuron which was inhibited by xanthine oxidase(XO) and hypoxanthine(HX)-induced oxigen radicals, MTT assay, NR assay, Neurofilament enzymeimmuno assay and LDH activity assay were carried out after the cultured mouse spinal sensory neuron were preincubated with various concentrations of BPT water extract for 3 hours prior to exposure of XO/HX. The results obtained were as follows: 1. XO/HX, a oxigen radical, decreased the survival rate of the cultured mouse spinal sensory neuron cell on NR assay and MTT assay. 2. $MTT_{50}$ value and $NR_{50}$ value of XO/HX were 30 mU/ml XO/O.2 mM HX. 3. BPT water extract have efficacy of increasing neurofilament. 4. BPT water extract have efficacy of increasing LDH activity. From above the results, It is concluded that BPT has marked efficacy as a treatment for the damages caused in the XO/HX-mediated oxidative process.

• 자원리싸이클링
• /
• 제8권3호
• /
• pp.37-42
• /
• 1999

오래전에 가행되었던 일부 금 광산에서 폐기된 광미엔는 미회수돈 금 및 시리카 등의 유가광물을 함유하고 있는 것으로 알려져 있으므로, 이들의 유가자원을 회수하기 위한 분리특성을 검토하였다. 처리공정은 가능한 경제성 확보를 위하여, 분급, 자력선별 및 비중선별 등 단순한 분리 공정을 적용하였으며, 본 공정에 으히ㅏ여 부리 회수된 유가지원으로는 금 농축 정광 0.87wt%[금 함유량 307.7 g/ton(0.6.wt%), 97.7 g/ton(0.27wt%)와 Sio$_2$ 품위가 96.40wt% 인 고품위 실리카를 60.65 Wt% 회수 할 수 있었다. 본 연구의 경과는 광산 폐기물 중에서 유가자원을 회수하거나 광산폐기물의 무해화 및 감량화를 목적으로 하는 공정수립에 참고자료가 될 수 있을 것이다.

• Journal of Biosystems Engineering
• /
• 제30권4호
• /
• pp.242-248
• /
• 2005

There was no useful milling standard to produce high quality milled rice efficiently and adequately in Rice Processing Complex. Therefore, the whiteness of milled rice produced Rice Processing Complexes were different according to Rice Processing Complexes and milling periods at the same Rice Processing Complex. This research was carried out to contribute the production and distribution of high quality milled rice through determination of whiteness condition of milled rice as a milling stndard based on degree of bran removal using New $May-Gr\ddot{u}wald$ reagent dyeing method and taste of cooked rice. The optimum whiteness value of milled rice for efficient milling in Rice Processing Complex was found to be from 40 to 41, while the degree of milling was from $8.9\%\;to\;9.2\%.$ At this whiteness condition, the first derivative of whiteness value according to degree of milling was higher than the average value from brown rice to well milled rice, and the broken kernel ratio was from $3.0\%\;to\;3.4\%.$ This whiteness condition ($40\~41$) could be considered as a milling condition in Rice Processing Complex.

• 한국대기환경학회지
• /
• 제8권3호
• /
• pp.155-161
• /
• 1992

A simple, fast yet sensitive method is described for the determination of fifty elements in coal by inductively coupled plasma mass spectrometry. The method involves complete dissolution of coal with mixed acid $(HNO_3, HF, HClO_4)$ in hish pressure Teflon bomb and subsequent inductively coupled plasma mass spectrometric(ICP-MS) measurement. The accuracy of the method, being evaluated by the analysis of NIST SRMs (1632a, 1632b) is better than 20% RSD for most elements. The limits of detection defined by two times $\sigma$ (standard deviation of operational blank) are in order of sub-ppm to ppm, which are low enough to quantitate most elements. However, the determiantions for few elements such as V, As, Se are severely interfered by molecular ions such that their accurate determiantions are not possible. Analytical results for twentyon coals from eight countries including six ones world major coal producing, Korea, Japan, China, I.C.S., U.S.A., Canada, Australia, and South Africa are presented. While the results for major elements agree well with the existing ones, those for a few trace elements disagree considerably. The existing values are considerably higher. It is not possible to judge which are more accurate. However, the exisisting values are more likely to be errorous inasmuch as they are obtained without using high purity reagents and clean laboratory techniques.

• 천문학회보
• /
• 제36권1호
• /
• pp.30.1-30.1
• /
• 2011

2010년 11월 05일부터 11월 29일 중 총 12일간 진천 소재 충북대학교 천문대의 60cm 반사망원경과 ST-8 CCD 카메라를 이용하여 BD And의 BVR CCD 측광 관측을 수행하여 처음으로 BVR 광도 곡선을 완성하였다. 또한, 극심시각 결정을 위한 측광관측이 레몬산 천문대 1m 반사 망원경과 충북대학교 천문대의 35cm 망원경으로 수행되었다. 우리의 관측을 통하여 모두 19개의 극심시각을 새로이 결정하였다. 새로운 관측은 이 별의 공전주기가 이전까지 알려진 0.4629일이 아니라 그 두 배인 0.9258일이며, 기산점도 반주기 바뀌어야 함을 보여준다. BD And의 광도요소를 $MinI=HJD2434962.8602+0.^d9258054E$으로 새롭게 개정하였다. 이 광도요소로 작성한 우리의 BVR 광도곡선은 제1식과 제2식의 깊이가 거의 비슷하며, 식바깥 부분에 잘 발달된 파형 모양을 보인다. 이는 BD And가 짧은 주기의 RS CVn형 식쌍성임을 나타내는 것이다. 우리의 극심시각을 포함한 총 130개의 극심시각에 대한 (O-C)도를 작성한 결과, BD And의 공전주기가 규칙적으로 변화하는 것을 발견하였다. 이 변화를 보이지 않는 제3천체에 의한 광시간 효과로 가정하여, 궤도이심율이 0.78이며, 9.19년의 주기를 가진 광시간 궤도를 결정하였다. 우리의 광도곡선을 2003년 Wilson-Devinney 쌍성 모형으로 분석하여 광도곡선 해를 질량비 q=0.094, 궤도경사각 $i=85.^{\circ}4$, $T_1=6365(K)$, $T_2=6250(K)$, $R_1=1.132(Rsun)$, $R_2=1.304(Rsun)$와 같이 산출하였다. 식바깥에서 나타나는 파형 모양의 변화는 주성의 표면에 매우 큰 흑점으로 잘 설명되며, BVR 광도곡선에서 각전체 광도의 각 8.3%, 10.0%, 11.7%에 해당되는 제3 광도가 검출되었다. 이는 주기연구에서 제안된 제3천체의 존재 가능성을 더 공고히 한다.