• 제목/요약/키워드: Moelcular

검색결과 11건 처리시간 0.02초

Pathogenesis of Minimal Change Nephrotic Syndrome: A Review of the Underlying Molecular Mechanisms

  • Yang, Eun Mi
    • Childhood Kidney Diseases
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    • 제23권1호
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    • pp.1-6
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    • 2019
  • Nephrotic syndrome (NS) is the most common glomerular disorder in childhood, and a vast majority of cases are idiopathic. The precise cause of this common childhood disease is not fully elucidated despite significant advancements in our understanding of podocyte biology. Idiopathic NS has been considered "a disorder of T-cell function" mediated by a circulating factor that alters podocyte function resulting in massive proteinuria since the last four decades. Several circulatory factors released from T-cells are considered to be involved in pathophysiology of NS; however, a single presumptive factor has not been defined yet. Extended evidence obtained by advances in the pathobiology of podocytes has implicated podocytes as critical regulator of glomerular protein filtration and podocytopathy. The candidate molecules as pathological mediators of steroid-dependent NS are CD80 (also known as B7-1), hemopexin, and angiopoietin-like 4. The "two-hit" hypothesis proposes that the expression of CD80 on podocytes and ineffective inhibition of podocyte CD80 due to regulatory T-cell dysfunction or impaired autoregulation by podocytes results in NS. Recent studies suggest that not only T cells but also other immune cells and podocytes are involved in the pathogenesis of MCNS.

Streptomyces속 균주가 생성하는 $\alpha$-D-Glucosidase 저해물질의 물리학적 성질 (Physico-Chemical Characteristics of $\alpha$-D-Glucosidase Inhibitor from Streptomyces sp)

  • 도재호;주현규
    • 한국미생물·생명공학회지
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    • 제18권1호
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    • pp.35-38
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    • 1990
  • 정제된 저해물질의 Rf치는 0.12-0.71 사이였으며 melting point는 154.3-155.3$^{\circ}C$로 나타났다. 물, formic acid, ethylene glycol monomethyl ether에는 용해되지만 그외 대부분의 용매에서는 불용성이었고 흡습성이 매우 큰 물질이었다. Phenol-sulfuric acid, ninhydrin, silvernitrate-sodium hydroxide 반응은 양성이었으나, DNS 반응에서는 음성이며 자외선 조사하에서 형광을 나타내었다. 저해물질의 구성성분은 fructose와 aspartic acid로 확인되었으며 분자량이 약 1,050 정도였다.

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열수 및 알칼리 용액을 이용한 국산 목재 칩으로부터 헤미셀룰로오스의 선추출 및 특성 구명 (Pre-extraction of Hemicelluloses from Korean Mixed Hardwood Chips Using Hot Water and Alkali Solution and its Characteristics)

  • 조휘;신희내;심규정;윤혜정;이학래
    • 펄프종이기술
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    • 제43권1호
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    • pp.83-91
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    • 2011
  • Hemicelluloses are useful materials for papermaking and other biotechnological applications. To recover and further utilize the hemicelluloses, this study carried out the pre-extraction of the hemicelluloses from Korean mixed hardwoods chips using hot water and sodium hydroxide solution at various temperature and time conditions. Through the hot water pre-extraction, the wood components of 22% was extracted and the 35% of the hemicelluloses which were contained in the original wood chips were dissolved into the pre-extractives. The yield of the pre-extractives was more significantly influenced by the pre-extraction temperature than the time. The pre-extractives with the yield of 30% could be obtained by alkali pre-extraction and alkali concentration was the most important factor. It had lower hemicellulose content but high molecular weight, compared with the hot water pre-extractives.

The crystal and molecular structure of sulfisoxazole

  • Koo, Chung-Hoe;Shin, Hyun-So;Cho, Sung-Il
    • Archives of Pharmacal Research
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    • 제5권2호
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    • pp.79-86
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    • 1982
  • Sulfisoxazole, $C-{11}H_{13}N_{3}S$, crystallized in the orthohombic system, space group Pbca, with a = 14.492(1), b = 11.563(1), c = 14.900(2) $\AA$ and Z = 8. Intensities for 1867(1360 observed) unique reflections were measured on a four-circle diffractometer wirh CuKa radiation ($\lambda$ = 1.5418$\AA$). The structure was solved by heavy atom methods and refined by full-matrix least-squares procedures to a final R of 0.094. The benzene ring plane makes an angle of $68^{\circ}C$ with the plane of the isoxazole ring, which is plannar. The conformational angle formed by the torsional angle C(4)-S-N(2)-C(7) is $54^{\circ}C$. There are two intermolecular hydrogen bonds in the structure. One of them is of the type N-H...H with the length 2.915$\AA$. Thus two dimensional networks of hydrogen bonds form infinite moelcular sheets parallel to the (001) plane. Adjacent sheets are bound together by van der Waals forces.

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수용액 내에서 수용성개시제를 이용한 단분산성 폴리아크릴산의 용액중합 (Preparation of Monodisperse Poly(Acrylic acid) with a Water-Soluble Initiator by Solution Polymerization in Aqueous Phase)

  • 박문수;김예지
    • Elastomers and Composites
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    • 제49권3호
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    • pp.232-238
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    • 2014
  • 수용성 단량체인 아크릴산 (AA)을 단량체로 potassium persulfate (KPS)를 개시제로 이용하여 $60^{\circ}C$에서 $90^{\circ}C$ 사이의 선택된 온도에서 물을 반응매체로 하여 용액중합을 진행하였다. 아크릴산의 농도가 감소하거나 개시제의 농도가 증가하면 분자량은 감소하였다. 중합반응온도를 상승하면 폴리아크릴산 (PAA)의 분자량은 감소하였다. 대부분의 중합반응에서 분산성지수는 1.5 에 근접하는 것으로 관찰되었다. 교반속도가 증가하면서 400 rpm에서 분자량은 최고값을 나타낸 후, 교반속도가 800 rpm에 이르면서 수평균 및 중량평균분자량은 감소하였다. 유리전이온도는 분자량에 따라 크게 변하지 않았으며 $113^{\circ}C$에서 $116^{\circ}C$ 사이의 값을 나타내었다.