• 한국산업보건학회지
• /
• 제23권3호
• /
• pp.273-286
• /
• 2013

Objectives: The present study was conducted in order to investigate the reproductive toxicity in rats exposed to 1,4-dichlorobutane. Methods: The test chemical was administered orally at 0, 8.3, 50 and 300 mg/kg/day. Males were administered daily for 10 weeks prior to the mating period. Females were administered from between two weeks before mating to the 21stday of lactation. Results: In both sexes, a decrease in body weight and an increase in the weights of the liver and kidneys were observed. In males, discoloration of the liver, hepatocyte hypertrophy and mineralization in the kidneys were observed. In females, animal deaths, dystocia and pup deaths due to maternal dysfunction were observed. In F1 animals of both sexes, a decrease in body weight was observed at 300 mg/kg/day. An increase in the weights of the liver in both sexes, mineralization in the kidneys of males, animal deaths, hepatocyte hypertrophy and pup deaths due to maternal dysfunction were observed at 50 mg/kg/day. Mineralization in the kidneys of males was observed at 8.3 mg/kg/day. Therefore, the no-observed-adverse-effect levels (NOAELs) of 1,4- dichlorobutane were considered to be under 8.3 mg/kg/day for males, 8.3 mg/kg/day for females, more than 300 mg/kg/day for fertility in both sexes, 8.3 mg/kg/day for maternal functions and 50 mg/kg/day for F1 offspring. The absolute toxic dose was believed to be 8.3 mg/kg/day for males, 50 mg/kg/day for females, 50 mg/kg/day for maternal functions and 300 mg/kg/day for F1 offspring. However NOAEL for fertility could not be determined since there were no treatment-related changes. Conclusions: Under the present experimental conditions, 1,4-dichlorobutane is a Category 1B Reproductive Toxicant (presumed human reproductive or developmental toxicant).

• 공업화학
• /
• 제27권4호
• /
• pp.380-385
• /
• 2016

최근 셀룰로오스 나노피브릴과 셀룰로오스나노크리스탈과 같은 나노셀룰로오스는 관심의 초점이 되고 있다. 나노셀룰로오스의 표면에 있는 수산기는 고분자복합체의 보강재로 사용함에 있어서 적합한 기능을 소유하고 있기 때문이다. 본 연구에서 나노셀룰로오스를 시멘트복합체 제조에 있어서 보강재로서 사용하였다. 나노셀룰로오스는 TEMPO 산화에 의한 전처리과정을 거친 후, 균질화 및 초음파처리에 의해서 제조되었고, 투과전자현미경으로 나노셀룰로오스를 분석한 결과 직경이 10에서 15 nm 범위로 나타났다. 0.5% 나노셀룰로오스가 함유된 시멘트복합체의 압축강도를 기존 시멘트복합체와 비교하였으며 특히, 인장강도와 휨강도가 기존 시멘트복합체에 비해서 각각 49.7%와 38.8% 개선되었다. 그리고 나노셀룰로오스가 혼합된 시멘트복합체의 자기수축률은 타설 후 1일 경과 시 18.9%, 28일 경과 시 5.9%의 저감효과가 나타났다.

• 한국환경성돌연변이발암원학회:학술대회논문집
• /
• 한국환경성돌연변이발암원학회 2003년도 추계학술대회
• /
• pp.184-184
• /
• 2003

• Toxicological Research
• /
• 제21권1호
• /
• pp.1-14
• /
• 2005

Transgenic mouse models have been introduced and accepted by regulatory bodies as an alternative to carcinogenicity assay models to predict and evaluate chemical carcinogens. The recent research outcomes in transgenic mouse models have made progressive advances in the understanding of chemical carcinogenesis and the evaluation of potential human carcinogens. However, these models still remain to be insufficient assay systems although the insufficiencies have been recognised and are being resolved. Based on up to date information from literature, this review article intends to understand currently accepted transgenic mouse models, issues arising from study design, interpretation of the study, results of validation project and their cancer prediction rate, and further perspectives of cancer assay models from the regulatory view point.

• 한국재료학회지
• /
• 제24권12호
• /
• pp.677-681
• /
• 2014

To increase the mechanical property of zirconia, we have investigated the phase change and the resulting hardness of zirconia ceramics by hydroxyapatite (HA) powder bed sintering. It was observed using X-ray diffraction that the cubic zirconia phase, which has a higher hardness value than that of the tetragonal phase, was obtained at the surface of 3 mol% $Y_2O_3$ doped tetragonal zirconia polycrystal (3Y-TZP) ceramics during the sintering process; in our experimental conditions, the phase change at the surface increased as the sintering time increased. We believe that the observed crystalline phase change originated from the decomposition of HA and the diffusion of CaO, as follows. CaO, which was derived from the decomposition of HA at high temperature ($1400^{\circ}C$), diffused into the surface of 3Y-TZP and acted as a stabilizer. As a result, the Vickers hardness value of the treated specimens was higher than that of the non-treated specimen due to the formation of the cubic phase on the surface of 3Y-TZP.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1996년도 춘계학술대회
• /
• pp.235-235
• /
• 1996

1. 초산 writhing법에서 DA-5018, morphine, capsaicin 및 acetaminophen의 E $D_{50}$ 은 각각 0.1, 0.3, 1.4 및 45.4 mg/kg이었으며, formalin법에서 DA-5018과 morphine의 E $D_{50}$은 0.17과 4.3 mg/kg이었다. Randall-Selitto법에서 DA-5018, morphine, capsaicin 및 acetaminophen의 E $D_{50}$은 0.66, 3.9, 4.2 및 643 mg/kg이었다. Tail flick법에서 DA-5018, morphine 및 capsaicin의 E $D_{50}$ 은 2.0, 2.6 및 14.2 mg/kg이었고 hot plate법에서 DA-5018과 capsaicin의 E $D_{50}$은 1.7 및 26.5mg/kg이었다. 그러나 열자극에 의한 동통모델에서 acetaminophen은 진통효과가 없었다. 2. Streptozotocin유발 당뇨랫드에 DA-5018 0.2, 0.5 및 1.0mg/kg 또는 capsaicin 10 mg/kg 투여시 1, 3, 7 일째에서 각각 유의성있는 동통역치의 증가를 나타내었으나 ketoprofen(10 mg/kg) 및 desipramin(10 mg/kg) 투여시는 동통역치의 유의성있는 증가가 나타내지 않았다. 관절염 동통모델에서 DA-5018, ketoprofen 및 capsaicin을 투여한 후 7일째에 동통역치를 2배 증가시키는 용량은 각각 0.66, 3.76 및 17.38 mg/kg이었다. 3. 이상의 결과로부터 DA-5018은 morphine 및 capsaicin에 비해 동등 이상의 효력을 갖고 있으며, 비스테로이드성 진통제보다 효능이 우수함을 확인하였다.

• Toxicological Research
• /
• 제22권2호
• /
• pp.127-133
• /
• 2006

Recently, we have reported that the environmental pollutant 2-bromopropane (2-BP) induces a significant embryo-fetal developmental toxicity in rats. However, the cause of developmental toxicity and the relationship between maternal and developmental toxicities could not be elucidated because the developmental toxicity of 2-BP was observed only in the presence of maternal toxicity The in vitro teratogenicity study using whole embryo culture was carried out to understand the teratogenic properties and the possible mechanism of teratogenicity induced by 2-BP in rats. Rat embryos aged 9.5 days were cultured in vitro for 48 hrs at medium concentrations of 0, 1, 3, or 10 mg/ml of 2-BP. Embryos were evaluated for growth, differentiation, and morphological alterations at the end of the culture period. At 10 mg/ml, 2-BP caused a delay in the growth and differentiation of embryos and an increase in the incidence of morphological alterations, including altered yolk sac circulation, abnormal axial rotation, craniofacial hypoplasia, open neuropore, absent optic vesicle and kinked somites. At 3 mg/ml, only a delay in the growth and differentiation of embryos was observed. There were no adverse effects on embryonic growth and development at the concentration of 1 mg/ml. The results showed that the exposure of 2-BP to rat embryos results in a developmental delay and morphological alterations at dose levels of 3 mg/ml culture media or higher and that 2-BP can induce a direct developmental toxicity in rat embryos.

• 펄프종이기술
• /
• 제32권2호
• /
• pp.8-15
• /
• 2000

This study is a continuation of the previous experimental analysis and is mostly focused on handsheet strength properties. Four completely different fibers, which were Hw-BKP, SW-BKP, White ledger, and OCC, were selected to investigate the effect of mechanical pre-treatment by Hobart mixer on handsheet strehgth properties. After equal time mechanical pre-treatment, the fibers were refined with laboratory valley beater for 10, 20 and 30 minutes, and handsheets were prepared from the fibers for physical strength comparison. Handsheets from SW-BKP and OCC showed 5-30% increase of breaking length, burst index, tear index, and compression index while handsheets from HW-BKP and White ledger no increase except tear index. In Hobart mixer pre-treatment, HW-BKP and White ledger fibers were easily attached to the wall of the mixer bowl and mechanical action was not effectively applied. The fiber length of Hw-BKP and White ledger were 0.837 mm and 1.591 mm, respectively, while SW-BKP and OCC were 2.744 mm and 2.033 mm, respectively, in weight weighted length. The effective mechanical pre-treatment seems to be related to the fiber length. Tear indexes of the pre-treated furnish were much higher than no pre-treatment at the same breaking length level.

• Journal of Microbiology and Biotechnology
• /
• 제28권3호
• /
• pp.367-374
• /
• 2018

RNA interference provides an effective tool for developing antitumor therapies. Cell-penetrating peptides (CPPs) are delivery vectors widely used to efficiently transport small-interfering RNA (siRNA) to intracellular targets. In this study, we investigated the efficacy of the cancer-specific CPP carrier BR2 to specifically transport siRNA to cancer-target cells. Our results showed that BR2 formed a complex with anti-vascular endothelial growth factor siRNA (siVEGF) that exhibited the appropriate size and surface charge for in vivo treatment. Additionally, the BR2-VEGF siRNA complex exhibited significant serum stability and high levels of gene-silencing effects in vitro. Moreover, the transfection efficiency of the complex into a cancer cell line was higher than that observed in non-cancer cell lines, resulting in downregulated intracellular VEGF levels in HeLa cells and comprehensively improved antitumor efficacy in the absence of significant toxicity. These results indicated that BR2 has significant potential for the safe, efficient, and specific delivery of siRNA for diverse applications.

• 한국기술혁신학회:학술대회논문집
• /
• 한국기술혁신학회 2003년도 춘계학술대회
• /
• pp.413-425
• /
• 2003

Information Technology is the kernel technology deciding the industrial standard of one nation, and biotechnology will be the main technology of next generation. Based on this fact, a lot of efforts were made to industrialize them. Nano Technology is beginning to position itself as the kernel fusion technology, and its usage and popularity is expanding. Environmental and Energy Technology is a must-have strategic technology considering the increase demand of new energy development, the international environment correspondence, the environment-friendly production, and so forth. Space Technology is the field, which will contribute to raise the domestic component and system technology to the next level. In 2001, new technology research development costs total of 1 trillion 32 billion won in the following fields; 437.82 billion won in IT, 88.457 billion won in BT, 46.799 billion won in NT, 315.682 billion won in ET, and 112 billion won in ST. from component ratio, IT forms 42% which is the most, 31% for ET and in order of BT, ST and NT. ETRI and KISTI are concentrating on IT, KIBB is on BT, KAERI, KIER, KERI and KBSI are focusing on ET, and KIMM, KRISS, KRICT and KORDI is participating together in 4∼5 new technology such as IT, BT, NT and ET. Funds for research development costs in 5 new technology fields of 13 contribution (year) are consisted as follows; The Office for Government Policy Coordination has contributed 131 billion won (13%), 387 billion won (37%) by MOST, 256 billion won (25%) by Ministry of Information and Communication, 67 billion won (6%) by Ministry of Commerce, Industry and Energy, 19% by others and the industrial world. < Strategy for Technology Advancing > o Promotion of comprehensive contributing (year) new technology development research plan project o Increase research efficiency by promoting new technology development project connected with peculiar projects of organization by contribution (year) o Formation of superior research group by technology and introduction of operation system for research accumulation are needed. o Technology demand-oriented assignment deduction and promotion of research development project connected with intermediate long term objective o National will and investment extension of research development costs, training and popularization of professionals, commercialization promotion with efficient control for research plan and result.