• Title/Summary/Keyword: MgB2

Search Result 4,790, Processing Time 0.037 seconds

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

  • Na, Seok-Ju;Gwak, Mun-Seop
    • Journal of Chest Surgery
    • /
    • v.22 no.6
    • /
    • pp.914-920
    • /
    • 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.

  • PDF

Production and Mechanical Properties of Mg-Zn-Ce Amorphous Alloys by Dispersion of Ultrafine hcp-Mg Paticles (hcp-Mg 입자분산형 Mg-Zn-Ce계 비정질합금의 제조와 기계적 성질)

  • Kim, Seong-Gyu;Park, Heung-Il;Kim, U-Yeol;Jo, Seong-Myeong;Kim, Yeong-Hwan;Inoue, A.;Masumoto, T.
    • Korean Journal of Materials Research
    • /
    • v.4 no.8
    • /
    • pp.847-854
    • /
    • 1994
  • An amorphous single phase and coexistent amorphous and hcp-Mg phases in Mg-Zn-Ce system were found to form in the composition ranges of 20 to 40% Zn, 0 to 10% Ce and 5 to 20% Zn, 0 to 5% Ce, respectively. A $Mg_{85}Zn_{12}Ce_{3}$ amorphous alloy containing nanoscale hcp-Mg particles was found to form either by melt spinning or by heat treatment of melt -spun ribbon. The particle size of the hcp-Mg phase can be controlled in the range of 4 to 20 nm. The mixed phase alloy prepared thus has a good bending ductility and exhibits high ultimate tensile strength($\sigma_{B}$) ranging from 670 to 930 MPa and fracture elongation($\varepsilon_{f}$) of 5.2 to 2.0%. The highest specific strength($\sigma_{B}$/density =$\sigma_{s}$)$3.6 \times 10^5N \cdot m/kg$. It should be noted that the highest values of flB, US and ?1 are considerably higher than those (690MPa,$2.5 \times 10^5N \cdot m/kg$and 2.5%) for amorphous Mg-Zn-Ce alloys. The increase of the mechanical strengths by the formation of the mixed phase structure is presumably due to a dispersion hardening of the hcp supersaturated solution which has the hardness higher than that of the amorphous phase with the same composition.

  • PDF

Microwave dielectric properties of $0.96MgTiO_3-0.04SrTiO_3$ ceramics with $B_2O_3$ ($B_2O_3$ 첨가에 따른 $0.96MgTiO_3-0.04SrTiO_3$의 마이크로파 유전특성)

  • Kim, Jung-Hun;Choi, Eui-Sun;Lee, Mun-Ki;Jung, Jang-Ho;Lee, Young-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.07b
    • /
    • pp.682-685
    • /
    • 2002
  • The $0.96MgTiO_3-0.04SrTiO_3$ ceramics with $B_2O_3$(10wt%) were prepared by the conventional mixed oxide method. The structural properties were investigated with sintering temperature by XRD. According to the X-ray diffraction pattern of the $0.96MgTiO_3-0.04SrTiO_3$ ceramics with $B_2O_3$(10wt%), the ilmenite $MgTiO_3$ and perovskite $SrTiO_3$ structures were coexisted and secondary phase of the $MgTi_2O_5$ were appeared. In the case of $0.96MgTiO_3-0.04SrTiO_3+B_2O_3$(10wt%) ceramics sintered $1225^{\circ}C$, dielectric constant, quality factor and temperature coefficient of resonant frequency were 19.82, 62,735GHz, $-2.983ppm/^{\circ}C$, respectively.

  • PDF

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
    • /
    • v.12 no.2
    • /
    • pp.75-81
    • /
    • 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.

Stuy on the Composition of Pleurotus ferulae Fruit Body (아위버섯의 성분에 관한 연구)

  • 차월석;이희덕;김종수
    • Journal of Life Science
    • /
    • v.14 no.2
    • /
    • pp.205-208
    • /
    • 2004
  • The composition of Pleurotus ferulae fruit body (PFF) has been investigated to determine the possible use for medicinal and edible purposes. The nutritional compositions of PFF were as follows; carbohydrate 54.3 g%, crude protein 20.2 g%, moisture 12.5 g%, crude fat 8.0 g% and ash 5.0 g% (w/w). Potassium concentration in PFF was high up to 2,337.0 mg% (w/w) and Mg, Na, Zn, Ca and Fe were followed. There were seventeen amino acids in PFF. The glutamic acid content was high up to 13.65% mol and aspartic acid, glysine, alanine, leucine, arginine, valine and lysine were followed. Since PFF contains major free amino acids such as alanine, phenylalanine, tyrosine and leucine, it will be a favorable food stuff, Vitamin contents of PFF were vitamin A 0.12, vitamin B$_1$ 0.31, vitamin B$_2$ 0.68, vitamin C 7.99, vitamin E 316.88 and vitamin D$_3$ 0.29 mg%. PFF will have a good anti-aging effect due to the high content of vitamin C and E.

Flux pinning and critical current density in $TiO_2$-doped $MgB_2$ superconductor

  • Gang, Ji-Hun;Park, Jeong-Su;Park, Jin-U;Lee, Yeong-Baek;Prokhorov, V.G.
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2010.08a
    • /
    • pp.172-172
    • /
    • 2010
  • $MgB_2$ doped with $TiO_2$ was prepared by the in-situ solid state reaction to study the effects of $TiO_2$ dopant on the flux pinning behavior of $MgB_2$ superconductor. From the field-cooled and the zero-field-cooled temperature dependences of magnetization, the realms of vortex-glass and vortex-liquid states of $TiO_2$-doped $MgB_2$ were determined in the H-T diagram (the temperature dependence of upper critical magnetic field and irreversibility line). The critical current density was estimated from the width of hysteresis loops in the framework of Beam's model at different temperatures. The results indicate that nano-scale $TiO_2$ inclusions play a role of the effective pinning centers and lead to the enhanced upper critical field and critical current density. It is suggested that the grain-boundary pinning mechanism is realized in $TiO_2$-doped $MgB_2$ superconductor.

  • PDF

Influence of Ag Addition on Superconducting Property of Carbon-black Doped $MgB_2$ Superconductor (카본블랙이 도핑 된 $MgB_2$ 초전도체의 Ag 첨가의 영향)

  • Kim, H.J.;Kim, H.J.;Kim, C.J.;Park, H.W.
    • Progress in Superconductivity
    • /
    • v.12 no.1
    • /
    • pp.1-5
    • /
    • 2010
  • In this work we synthesized both MgB2 and Carbon doped MgB2 superconductor with Ag addition via high energy milling and substituent heat treatment. Heat treatments were performed at $900\;^{\circ}C$ for 30 min in flowing Ar gas. We varied amount of Ag powder. In a range of Ag powder was 0~5wt%. The effect of Ag was correlated with superconducting properties. The results show a slight decrease in critical temperature ($T_c$) and a reduction of critical current density ($J_c$) at high fields for the Ag-doped samples as compared to the un-doped samples. Reduction of $J_c$ may be due to the formation of MgAg compound.

B-site Cationic Ordering Structures of Donor-Doped Relaxor Ferroelectric $Pb({Mg_{1/3}}{Nb_{2/3})}O_3$ (전자 주게가 첨가된 완화형 강유전체 $Pb({Mg_{1/3}}{Nb_{2/3})}O_2$의 B자리 양이온 질서배열구조)

  • Cha, Seok-Bae;Kim, Byeong-Guk;Je, Hae-Jun
    • Korean Journal of Materials Research
    • /
    • v.10 no.7
    • /
    • pp.478-481
    • /
    • 2000
  • Single phase $Pb(Mg_{1/3}Nb_{2/3})O_3$ ceramics doped by 10 mol% of electron donors such as $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$, were synthesized and their B-site cationic ordering structures were investigated by XRD and TEM. In the XRD patterns, only fundamental reflections were observed for the undoped $Pb(Mg_{1/3}Nb_{2/3})O_3$, while the (h/2 $\textsc{k}$/2ι/2)(h,$\textsc{k}$,ι all odd) superlattice reflections resulting from the 1:1 ordering induced unit cell doubling were also observed for the donor-doped $Pb(Mg_{1/3}Nb_{2/3})O_3$. In the TEM selected area diffraction patterns, the (h/2 k/2 l/2)(h,k,l all odd) superlattice reflection spots as well as the fundamental reflection spots were observed for all the samples, but the relative intensities of the superlattice reflection spots to the fundamental reflection spots were significantly enhanced by the donor-doping. In the TEM dark-field images, antiphase boundaries were observed only for the donor-doped $Pb(Mg_{1/3}Nb_{2/3})O_3$. It was therefore experimentally verified that doping by electron donors such as $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$, enhances the B-site cationic 1:1 ordering in $Pb(Mg_{1/3}Nb_{2/3})O_3$. These experimental results were interpreted in terms of the charge compensation mechanism.

  • PDF