• 제목/요약/키워드: $MgB_6$

검색결과 2,907건 처리시간 0.04초

Progress in $MgB_2$ Superconductor Wires and Tapes

  • Kim, Jung-Ho;Kumakura, Hiroaki;Rindflesich, Matthew;Dou, Shi Xue;Hwang, Soo-Min;Joo, Jin-Ho
    • Progress in Superconductivity
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    • 제12권2호
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    • pp.75-81
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    • 2011
  • We report on the progress that has been made in developing $MgB_2$ superconducting wires and tapes for commercialization and research efforts. A number of techniques have been developed to overcome the obstacle posed by the poor critical current density ($J_c$) of pristine $MgB_2$. Chemical doping has proved to be the effective way to modify and enhance the superconducting properties, such as the $J_c$ and the irreversibility field ($B_{irr}$). More than 100 different types of dopants have been investigated over the past 8 years. Among these, the most effective dopants have been identified to be SiC and malic acid ($C_4H_6O_5$). The best results, viz. a $B_{irr}$ of 22 T and $J_c$ of $30,000\;A{\cdot}cm^{-2}$ at 4.2 K and 10 T, were reported for malic acid doped $MgB_2$ wires, which matched the benchmark performance of commercial low temperature superconductor wires. In this work, we discuss the progress made in $MgB_2$ conductors over the past few years at the University of Wollongong, Hyper Tech Research, Inc., and Ohio State University.

Bleomycin 과 Cyclophosphamide 의 병용투여가 흰쥐의 폐독성에 미치는 영향 (Experimental Studies on the Pulmonary Toxicity of Combined Bleomycin and Cyclophosphamide Administration in Rats)

  • 나석주;곽문섭
    • Journal of Chest Surgery
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    • 제22권6호
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    • pp.914-920
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    • 1989
  • Bleomycin and cyclophosphamide are widely used and effective anti-cancer agents for treatment of various forms of cancer. Bleomycin has no myelotoxicity, but because of potential risk of pulmonary complications including interstitial pneumonitis and idiopathic interstitial pulmonary fibrosis, it has been limited in use. Some investigator has also suggested that cyclophosphamide can induce pulmonary toxicity like bleomycin. Recently, The combination chemotherapy including bleomycin and cyclophosphamide has been adopted effectively in some types of cancer. But there are no available literatures for synergistic effect of pulmonary toxicity in combination chemotherapy including these two drugs. We tried this study to observe synergism of pulmonary toxicity using these two drugs in rats. The animals were divided into five groups: group 1 received intra-peritoneal injection of saline, group 2-a received only bleomycin 0.1 mg [0.4 mg/kg] by intra-peritoneal injection twice a week, group 2-b received only bleomycin 0.5 mg [2 mg/kg] by intra-peritoneal injection twice a week, group 3-a received bleomycin 0.1 mg [0.4 mg/kg] twice a week +cyclophosphamide 5 mg [20 mg/kg] two weeks interval by intra-peritoneal injection, group 3-b received bleomycin 0.5 mg [2 mg/kg] twice a week + cyclophosphamide 5 mg[20 mg/kg] two weeks interval by intra-peritoneal injection. The animals were sacrificed at 2 and 4 weeks later. Lung tissues were obtained and observed by light microscope. The results are as follows: 1. The pathologic findings of group 1 were normal without change. 2. There was no difference between group 2-a and group 3-a at 2 weeks later, group 3-a, however, revealed more severe change in lung tissue at 4 weeks later compared with group 2-a. 3. In group 3-b there was more severe pulmonary injury compared with group 2-b at 2 and 4 weeks later. We conclude that the combined administration of bleomycin and cyclophosphamide induce more severe pulmonary toxic effect than bleomycin administration alone and the combination chemotherapy including these two drugs will be require special attention to selection of the dose of each drug.

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Aspergillus oryzae 또는 Bacillus natto 발효콩의 Isoflavone 함량과 생리활성 (Isoflavones Contents and Physiological Activities of Soybeans Fermented with Aspergillus oryzae or Bacillus natto)

  • 정우열;김성기;손종연
    • 한국식품영양과학회지
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    • 제37권2호
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    • pp.141-147
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    • 2008
  • 본 연구에서는 Asp. oryzae 및 B. natto로 각각 발효시킨 콩의 이소플라본의 함량변화, 생리활성에 대하여 비교, 조사하였다. 총 이소플라본 함량은 비발효콩이 81.80 mg/100 g, Asp. oryzae 발효콩이 130.70 mg/100 g, B. natto 발효콩이 139.50 mg/100 g이었다. 비발효콩, Asp. oryzae 발효콩 및 B. natto 발효콩의 총 페놀 함량은 각각 2.1, 4.3 및 7.6%이었고, 아질산염소거능은 각각 34.2, 55.2 및 92.5%로 측정되었다. 항균효과의 경우, B. natto 발효콩은 Staphylococcus aureus, Bacillus cereus와 Escherichia coli에서 가장 강한 항균효과가 나타났다. Asp. oryzae 발효콩은 Staphylococcus aureus와 Salmonella Enteritidis에서 항균효과를 보였다. 전체적으로 B. natto 발효콩의 항균성이 강하였다. SOD 유사활성은 Asp. oryzae 발효콩에서 가장 강했던 반면, 전자공여능에서는 B. natto 발효콩에서 가장 강한 radical 소거능이 측정되었다. 리놀레산 기질에 대한 Asp. oryzae 발효콩의 항산화 효과는 비발효콩이나 B. natto보다 큰 것으로 나타났으나, 유의적인 차이는 없었다.

메밀화분의 성분 특성 및 항산화 활성 (Chemical Composition and Antioxidant Activity of Korean Buckwheat (Fagopyrum esculentum) Pollen Grain Collected by Honey Bee, Apis mellifera)

  • 홍인표;우순옥;한상미;이미경
    • 한국양봉학회지
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    • 제32권3호
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    • pp.261-268
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    • 2017
  • 벌화분은 생리활성 물질이 풍부한 완전식품으로 알려져 수요가 급증하고 있으나 봄철에 도토리화분과 다래화분 등 몇 종의 화분만 수집되어 생산량이 부족한 실정이다. 본 연구에서는 건강 및 기호식품으로 재배면적이 계속 증가하는 메밀 화분을 가을 화분원으로 개발하고자 영양성분, 비타민, 미량원소, 항산화활성, 유리 아미노산 등을 평가하였다. 메밀화분의 일반성분은 수분 9.75%, 회분 5.18%, 조단백질 14.43%, 조지방 5.67%였다. 메밀화분에는 glutamic acid, aspartic acid, lysine 등의 아미노산의 함량이 주로 분포하였으며, tryptophan, cystine, tyrosine 등은 소량 존재하였다. 비타민 함량은 C 13.74mg/100g, $B_3$ 6.62mg/100g, $B_1$ 1.26mg/100g, $B_2$ 0.53mg/100g 순으로 존재하였다. 미량원소 함량은 칼륨(K) 119.95mg/100g과 인(P) 962.77mg/100g으로 많이 함유되어 있으며, 구리(Cu)와 아연(Zn)은 각각 0.46mg/100g, 1.59mg/100g으로 소량 존재하였다. 메밀화분의 DPPH에 대한 항산화활성은 $500{\mu}g/ml$ 에서 8.1%이었으며, 총페놀함량은 mg당 $2.25{\mu}g$이었다. 메밀화분은 조단백질, 조지방 등 영양성분이 모두 존재하였으며, 아미노산도 필수아미노산 8종을 포함하여 18종의 아미노산이 풍부하게 존재하였다. 또한 비타민도 C, $B_3$, $B_1$, $B_2$ 분포하였으며, 항산화 활성도 우수하여 가을 화분원으로 활용이 가능할 것으로 기대된다.

경남지역 중${\cdot}$장년층의 혈청지질, 아포지단백질의 농도 및 상호관련성에 관한 연구 (A Study on the Serum Lipid, Apolipoprotein Levels and Their Correlations in Healthy Adults of Gyeongnam Area)

  • 이효선;박미영;김경업;정효숙;김성희
    • Journal of Nutrition and Health
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    • 제40권6호
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    • pp.526-530
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    • 2007
  • The purpose of this study was investigating serum lipid, apolipoprotein levels and their correlations in healthy adults of Gyeongnam area. The BMI (body mass index) was significantly higher (p < 0.001) in male (25.2 ${\pm}$ 2.7 $kg/m^2$) than female (23.8 ${\pm}$ 1.5 $kg/m^2$), however PBF (percent body fat) was significantly higher (p < 0.001) in female (29.6 ${\pm}$ 4.3%) than male (22.7 ${\pm}$ 5.0%). The WHR (waist to hip ratio) and blood pressure in the groups showed there was no significant differences. The levels of serum total cholesterol, LDL-cholesterol and apolipoprotein B were significantly higher (p < 0.01) in male (208.7 ${\pm}$ 27.7 mg/dl, 129.0 ${\pm}$ 26.9 mg/dl, 1.0 ${\pm}$ 0.2 g/L) than female (193.6 ${\pm}$ 29.1 mg/dl, 112.5 ${\pm}$ 29.5 mg/dl, 0.9 ${\pm}$ 0.2 g/L, but HDL-cholesterol level was significantly higher (p < 0.01) in female (54.9 ${\pm}$ 6.6 mg/dl) than male (49.9 ${\pm}$ 7.3 mg/dl). The LDL-C/HDL-C, Apo B/Apo A-I and AI (atherogenic index) were significantly higher (p < 0.001) in male (2.6 ${\pm}$ 0.6, 0.8 ${\pm}$ 0.2, 3.3 ${\pm}$ 0.7) than female (2.1 ${\pm}$ 0.5, 0.6 ${\pm}$ 0.2, 2.6 ${\pm}$ 0.5). The triglyceride level was positively correlated with apolipoprotein B concentration (p < 0.05) and negatively correlated with HDL-cholesterol concentration (p < 0.05), however no significant correlation was found with apolipoprotein A-I. According to these results, we conclude that male adults are expecting higher incidence of cardiovascular disease than female adults and we suggest the serum triglyceride should be kept normal level for the prevention of these diseases.

시설재배 수박 엽 적정양분함량 설정 (Establishment of Critical Ranges of Inorganic Nutrition Contents in Leaves of Watermelon(Cucurbita citrullus L.) in Protected Cultivation)

  • 이주영;박재홍;장병춘;이기상;현병근;황선웅;윤영상;송범헌
    • 한국토양비료학회지
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    • 제41권3호
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    • pp.158-163
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    • 2008
  • 시설재배 수박에 대한 적정 양분함량 기준을 설정하기 위하여 2004년부터 2006년까지 고창에서 시설수박의 엽 중 무기양분함량과 수량을 조사하였다. 그 결과 3년간 조사한 수박 재배 농가 포장을 대상으로 생육단계별 적정 양분함량 범위를 설정하였다. 수박 수량과 생육단계별 엽 중 무기양분함량은 정식후 20일이 가장 유의성 있는 상관을 보였으며 이 때 엽 중 다량원소 적정 함량 범위는 N 5.0~6.3%, P 0.30~0.57%, K 3.5~4.2%, Ca 1.7~3.8%, Mg 0.20~0.42% 이었다. Fe, Mn, Zn, Cu 및 B 등의 미량원소 적정함량 범위는 Fe $96\sim128mg\;kg^{-1}$, Mn $67\sim201mg\;kg^{-1}$, Zn $40\sim60mg\;kg^{-1}$, Cu $6\sim9mg\;kg^{-1}$ 및 B $41{\sim}82mg\;kg^{-1}$ 이었고, 적정 양분함량 범위로 설정한 값의 하한치를 양분 결핍, 상한치를 양분 과잉으로 판단했다. 본 시험연구결과 제시한 수박의 생육단계별 적정 양분함량 범위 기준은 농업현장에서 빈번히 발생하는 수박의 영양장애를 해결하기 위한 양분지표로 사용할 수 있을 것이라 생각된다.

$B_2O_3$의 첨가가 $(Zn_{0.8}Mg_{0.2})TiO_3$ 마이크로파 세라믹스에 미치는 영향 (Effect of $B_2O_3$ Addition on $(Zn_{0.8}Mg_{0.2})TiO_3$ Microwave Ceramics)

  • 심우성;방재철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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    • pp.677-680
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    • 2003
  • The effect of $B_2O_3$ addition on the sintering behavior and microwave dielectric properties of $(Zn_{0.8}Mg_{0.2})TiO_3$ ceramic system were investigated. Highly dense samples were obtained at the sintering temperatures below $900^{\circ}C$. Temperature coefficient of resonance frequency(${\tau}_f$) changes to a positive value with increasing the amount of $B_2O_3$ because of the increased amount of rutile phase. The $Q{\times}f_o$ values were determined by the microstructures and sintering shrinkages which are affected by the rutile or second phase. When 6.19 mol.% of $B_2O_3$ added and sintered at $900^{\circ}C$ for 5h, it exhibits ${\epsilon}_r$ =23.5, $Q{\times}f_o$= 67,500 GHz, and ${\tau}f=-1.42ppm/^{\circ}C$.

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Magnesium diboride(MgB2) wires for applications

  • Patel, Dipak;Kim, Jung Ho
    • 한국초전도ㆍ저온공학회논문지
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    • 제18권1호
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    • pp.1-5
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    • 2016
  • Field and temperature dependence of the critical current density, Jc, were measured for both un-doped and carbon doped $MgB_2/Nb/Monel$ wires manufactured by Hyper Tech Research, Inc. In particular, carbon incorporation into the $MgB_2$ structure using malic acid additive and a chemical solution method can be advantageous because of the highly uniform mixing between the carbon and boron powders. At 4.2 K and 10 T, Jc was estimated to be $25,000-25,300Acm^{-2}$ for the wire sintered at $600^{\circ}C$ for 4 hours. The irreversibility field, $B_{irr}$, of the malic acid doped wire was approximately 21.0 - 21.8 T, as obtained from a linear extrapolation of the J-B characteristic. Interestingly enough, the Jc of the malic acid doped sample exceeds $10^5Acm^{-2}$ at 6 T and 4.2 K, which is comparable to that of commercial Nb-Ti wires.

밀리타리스 동충하초($Cordyceps$ $Militalis$)열수 추출물이 스트렙토 조토신으로 유발된 당뇨 흰쥐의 항 당뇨 대사에 미치는 영향 (Antidiabetic Metabolism Effect on the water Extract of $Cordyceps$ $Militalis$ in Streptozotocin-Induced Diabetic Rats)

  • 김옥경
    • 한국응용과학기술학회지
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    • 제28권3호
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    • pp.267-272
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    • 2011
  • This study was carried to investigate the antidiabetic metabolism effect of water extract $Cordyceps$ $Militalis$(C.M.) in Streptozotocin(STZ) induced diabetic rats. Diabetes were induced by intravenous injection of STZ at a dose of 42mg/kg,b.w. dissolved in citrate buffer. The water extract of C.M. was orally administrated once a day for 7 days at a dose of 500mg/kg,b.w(body weight). or 1,000mg/kg.b.w. The content serum glucose was significantly decreased in C.M. treated group compared to the those of STZ-control group. The content of hepatic glycogen and activities of glucose-6-phosphate dehydrogenase(G-6-PDH), glucokinase(GK) were significantly increased, but activity of glucose-6-phoshatase(G-6-Pase) was significantly decreased in C.M. treated group compared to the those of STZ-control group. These results indicated that water extract of C.M. would have antidiabetic metabolism effect in STZ-induced diabetic rats.

유기인계 Chlorpyrifos가 생쥐에 미치는 급성 면역 독성 (Acute Immunotoxic Effects of Chlorpyrifos in CBA Male Mice)

  • 김강석
    • Environmental Analysis Health and Toxicology
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    • 제13권1_2호
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    • pp.33-41
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    • 1998
  • Chlorpyrifos, o,o diethyl-o-(3,5,6-trichloro-2-pyridyl) phosphorothioate, is a broad spectrum organophosphate insecticide. The use of chlorpyrifos has been increased more and more as pesticide. But the effects of chlorpyrifos on the immune alterations has not been yet observed. Therefore, we investigated the effects of chlorpyrifos on the immune alterations in CICA male mice. Chlorpyrifos was administered to mice by a single intraperitoneal injection for the purpose of observing acute effects. On the one hand to get the information on immunopathologic alterations we observed hematological values, counted total circulating leukocytes and assessed the ratio of lymphocytes and neutrophils from the peripheral blood, measured the ratio of organ/body weight and counted splenic cellularity in CBA male mice which treated chlorpyrifos intraperitoneally. But we could not find any significant immunopathologic alterations statistically by a single intraperitoneal injection. Also, the exposure of chlorpyrifos caused no significant change in the number of PFC/10$^6$ spleen cells at any three given doses. On the other hand a singte intraperitoneal injection of chlorpyrifos decreased the lymphocyte proliferation response slightly to ConA or LPS stimulation at a dose of 6 mg/kg b.w. Administrations of chlorpyrifos reduced mixed leukocyte response(MLR). MLR was decreased moderately at doses of 3mg/kg b.w. and 6mg/kg b.w. Therefore, all these findings suggest that chlorpyrifos may alter the immune functions acutely. especially by the changes of T lymphocyte activity.

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