• 제목/요약/키워드: abnormal growth

검색결과 708건 처리시간 0.029초

질화규소 세라믹스의 미세조직 형성에 미치는 Seed 첨가의 영향 (Effect of Seeding on Microstructural Development of Silicon Nitride Ceramics)

  • 이창주
    • 한국분말재료학회지
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    • 제5권2호
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    • pp.133-138
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    • 1998
  • The effect of $\beta$-$Si_3N_4$ seeding on microstructural development of silicon nitride based materials has been investigated. In particular, to observe more distinctly the abnormal grain growth in pressureless sintering, fine $\alpha$-$Si_3N_4$(mean particle size: 0.26 ${\mu}m$) powder classified by sedimentation method was used. It was possible to prepare silicon nitride with abnormally grown grains under low nitrogen pressure of 1 atm thanks to the heterogeneous nucleation on $Si_3N_4$ seed particles. The size and morphology of silicon nitride grains were strongly influenced by the presence of $\beta$-$Si_3N_4$ seed and overall chemical composition. For specimens with initially low $\beta$-content, the large grains grew without a significant impingement by other large grains. On the contrary, for specimens with initially high $\beta$-content, steric hindrance was effective. The resulting microstructure was less inhomogeneous and characterized by unimodal grain size distribution.

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Micropropagation of Kalopanax $pictus(T_{HUNB}.)\;N_{AKAI}$ by bud cultrue

  • Kim, Bong-Kyu;Yi, Yong-Sub;Ahn, Joong-Hoon
    • 한국약용작물학회지
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    • 제10권4호
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    • pp.249-252
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    • 2002
  • Several plant growth regulators were examined for on their effect on the in vitro propagation of Kalopanax pictus$(T_{HUNB}.)$ $(N_{AKAI}.)$ on WPM medium. Among the cytokinins tested, BA at $13.32\;{\mu}M$ appeared to be the most effective for multiple axillary shoot formation. Although the addition of $2.89\;{\mu}M\;GA_3$ promoted stem elongation, it produced morphologically abnormal leaves and stems. For rooting of the shoots, $4.9\;{\mu}M$ IBA seemed to be more effective than $2.69\;{\mu}M$ NAA. When the regenerated plants were transferred on artificial mixture containing vermiculite and peat-moss (1 : 1, v/v), 81% of them survived and grew normally.

$YBa_2Cu_3O_x$초전도체의 액상 소결과 $Y_2BaCuO_5$를 이용한 입자 크기 제어 (Liquid-Phase Sintering of $YBa_2Cu_3O_x$ Ceramic Superconductor and Grain Size Control Using $Y_2BaCuO_5$)

  • 노광수;이정용;위당문
    • 한국세라믹학회지
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    • 제27권3호
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    • pp.423-429
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    • 1990
  • YBa2Cu3Ox ceramics superconductors fabricated using solid state reaction usually contain second phases, such as BaCuO2 and CuO. These second phases are located long the grain boundaries and enhance the abnormal growth of YBa2Cu3Ox grains and, consequently, generate the microcracks. These second phaases were reduced by adding Y2BaCuO5 into solid state reacted YBa2Cu3Ox ceramics. Y2BaCuO5 reacts with grain boundary second phases and reduces the grian size of the ceramics. It was observed the critical current density was improved by adding Y2BaCuO5 into solid state reacted YBa2Cu3Ox ceramic superconductor.

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$BiNbO_4$세라믹스의 유전 특성과 미세구조에 관한 연구 (Microwave Dielectric Properties and Microstructure of $BiNbO_4$ Ceramics)

  • 고상기;김현학;김경용
    • 한국전기전자재료학회논문지
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    • 제11권3호
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    • pp.208-213
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    • 1998
  • Microwave dielectric properties of $BiNbO_4$ containing CuO and $V_2O_5$(BN ceramics). BN ceramic with 0.07wt% $V_2O_5$ and 0.03wt% CuO (BNC3V7) was sintered at $900^{\circ}C$ where it is possible for these to be co-fired with Ag electrode. The dielectric constant of 44.3, TCF (Temperature Coefficient of resonance Frequency) of 2 ppm/$^{\circ}$ and Q${\times}f_o$ value (product of Quality value and resonance Frequency) of 22,000GHz could be obtained from those ceramics. It is observed that orthorhombic structure was stable $1000^{\circ}C$. As sintering temperature increases, the dielectric properties decreased. The main reasons were abnormal grain growth and the main peak of triclinic moved from the main peak of orthorhombic.

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Dithiolo-thione 계열 유도체 SWU-20009의 Akt활성 저해 효과 (Inhibitory Effects of Dithiolo-thione Derivative SWU-20009 on Akt Activity)

  • 고종희;연승우;이홍섭;김태용;노동윤;신경순;홍순광;강상순
    • 약학회지
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    • 제48권2호
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    • pp.105-110
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    • 2004
  • Akt (or Protein Kinase B; PKB) is a serine/threonine kinase and is activated by phosphoinositide 3-kinase (PI3K) pathway. Recent evidence indicates that the abnormal activities or expression of Akt is closely associated with cancer, diabetes and neuro-degenerative diseases. These findings mean that Akt is likely to be a new therapeutic target for the treatment of disease. Here, we screened the effects of dithiolo-dithione derivatives such as SWU-20004, SWU-20009 and SWU-20025 on Akt activities. Among these compounds, only SWU-20009 (2-Thioxo-[1,3]dithiolo[4,5- $\beta$][1,4]dithiine-5,6-dicarboxylic acid dimethyl ester) inhibited the growth of KATOIII cell at micromolar range of concentration. Further investigation also revealed that SWU-20009 inhibited cellular Akt activity and induced apoptotic cell death.

좌창 치험 3례 (Three cases of acne)

  • 황순이;조원준;지선영;이상곤;황보민
    • 한방안이비인후피부과학회지
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    • 제19권3호통권31호
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    • pp.215-223
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    • 2006
  • Acne, which intrucdes the pilosebaceous unit, is a chronic inflammatory disease. The symptom of comedones, papules, pustules, cysts, nodules and scar mainly raises on the face, upper back, shoulder and neck. The cause of acne is the secreting growth of sebum, abnormal follicular keratiniziation, the form of group of propionibacterium acnes, and the respones of inflammation etc. But the original mechanism of the cytobiologic level is exactly not known yet. We treated three patients suffered from acne with acupuncture, venesection, Chungsangbangpung-tang, wet dressing with Gamihwangryunhaedok-tang. After treatments we observed the improvement. Based on this study, it is considered that acupuncture, venesection, Chungsangbangpung-tang wet drssing with Gamihwangryunhaedok-tang can be applied to the management of acne.

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Regulation of Pathological Markers during Hepatic Fibrogenesis in Rats

  • Jeong, Won-il;Jeong, Kyu-shik
    • 한국수의병리학회:학술대회논문집
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    • 한국수의병리학회 2003년도 추계학술대회초록집
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    • pp.16-16
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    • 2003
  • Hepatic fibrosis is a common response to various chronic hepatic injuries and occurs as a consequence of the transformation of hepatic stellate cells into myofibroblasts (MFBs) producing abnormal extracellular matrix which is mainly induced by transforming growth factor-beta (TGF-${\beta}$), especially TGF-${\beta}$1 [1,2]. As the liver becomes fibrotic, there are both quantitative and qualitative changes in several pathological markers related to the hepatic fibrosis. These fibrotic markers in liver are mainly consisted of several proteins and cytokines, but sometimes included specific type cells. The aim of this study was to detect expression and change of markers (TGF-${\beta}$, mallory body, cytokeratin, ${\alpha}$-SMA, hypoxia, collagen) during hepatic fibrogenesis. (omitted)

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결합체 첨가 방법이 Sr-ferrite의 미세구조와 자기적 성질에 미치는 영향 (Effect of Binder Addtion Method on Microstructure and Magnetic Prooperties of Sr-ferrite)

  • 이병교;김정주;조상희
    • 한국세라믹학회지
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    • 제27권4호
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    • pp.548-552
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    • 1990
  • Effects of binder addition method during compacting on microstructural change and magnetic characteristics of Sr-ferrite system was investigated. Used binders were PVA and PEG, which were added separately or simultaneously. After compacts were heated at 50$0^{\circ}C$ for 3hr in air for burning out all the binders, they were sintered at 125$0^{\circ}C$ for 2h. Based on results, in the case of using the two binders simultaneously, comparing to single binder system, compacted density was somewhat higher but sintered density was rather lower, and abnormal grain growth was accelerated. According to these sintering characteristics, remanent magnetization and coercive force were also diminished.

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응집입자가 $BaTiO_3$의 소결거동에 미치는 영향 (Effect of Aggregates on the Sintering Behavior of $BaTiO_3$)

  • 김진호
    • 한국세라믹학회지
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    • 제28권11호
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    • pp.926-934
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    • 1991
  • The effect of aggregates on the forming and sintering behaviors of BaTiO3 was studied. Aggregates and deaggregates of fine crystallite were obtained by thermal decomposition of oxalate coprecipitates and subsequently crushing them with a press, respectively. Large voids formed by packing of aggregates were not easily eliminated despite the successive destruction of aggregates with increasing forming pressure. As a result, compacts of aggregates showed inhomogeneity with larger mid-pore size and broader pore size distribution with respect to those of deaggregates. This inhomogeneity caused differential shrinkage and consequental internal stress, which retarded densification. The differential sintering increased the size of mid-pores in the initial stage, and formed duplex structure composed of dense region with abnormally grown grains and porous region with fine grains. The driving force of this abnormal grain growth shown in the specimens of aggregates was attributed to the minimization of the elastic strain energy due to internal stress.

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Use of sugammadex in Rett syndrome: A case report

  • Kupeli, Ilke;Tepe, Emine;Kuyrukluyildiz, Ufuk
    • Journal of Dental Anesthesia and Pain Medicine
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    • 제18권4호
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    • pp.261-265
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    • 2018
  • Rett syndrome (RS) is a neurodevelopmental disorder characterized by loss of cognitive, motor, and social skills, epilepsy, autistic behavior, abnormal airway patterns, gastroesophageal reflux, nutritional problems, and severe scoliosis. Although girls with RS show normal or near-normal growth until 6-8 months, they lose their skills after that. The anesthetic management of these patients requires care because of all these clinical features. Especially in the postoperative period, prolonged apnea is common and extubation is delayed. In this case report, the effect of using sugammadex was presented in a 16-year-old girl with RS. The patient's all bimaxillary teeth and 4 wisdom teeth were extracted under general anesthesia in one session with minimal surgical trauma and moderate bleeding. Sugammadex can be a rapid and reliable agent for the reversal of the neuromuscular block in neurodegenerative patients.