• 제목/요약/키워드: Calorimetry

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등온열량계를 사용한 고흡수성 재료의 유효흡수율 측정: 비표면적의 영향 (Effective Absorption Capacity of Highly Absorptive Materials using Isothermal Calorimetry, Considering the Effect of Specific Surface Area)

  • 이보연
    • 대한건축학회논문집:구조계
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    • 제34권2호
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    • pp.49-56
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    • 2018
  • The use of highly absorptive materials in cement-based materials is increasing for internal curing purpose. However, calculation of correct absorption capacity of such materials is not easy, which leads to change in the effective water-to-cement ratio of cement paste by either absorbing or releasing water. In this study, effective absorption capacity of a highly absorptive material was found using isothermal calorimetry. Moreover, the effect of specific surface area was investigated. It was found that the method was capable of finding effective water absorption capacity of activated carbon fiber. For the activated carbon fiber used in this research, the effect of specific surface area was negligible because the high BET surface area was due to micropores less than 1nm, which does not affect the rate of hydration curve. Thus, the effective absorption capacity of such materials can be found successfully using this method.

Engineering and Characterization of the Isolated C-Terminal Domain of 5-Enolpyruvylshikimate-3-phosphate (EPSP) Synthase

  • Kim, Hak-Jun;Kim, Hyun-Woo;Kang, Sung-Ho
    • Journal of Microbiology and Biotechnology
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    • 제17권8호
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    • pp.1385-1389
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    • 2007
  • 5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase catalyzes the formation of EPSP and inorganic phosphate from shikimate-3-phosphate (S3P) and phosphoenolpyruvate (PEP) in the biosynthesis of aromatic amino acids. To delineate the domain-specific function, we successfully isolated the discontinuous C-terminal domain (residues 1-21, linkers, 240-427) of EPSP synthase (427 residues) by site-directed mutagenesis. The engineered C-terminal domains containing no linker (CTD), or with gly-gly ($CTD^{GG}$) and gly-ser-ser-gly ($CTD^{GSSG}$) linkers were purified and characterized as having distinct native-like secondary and tertiary structures. However, isothermal titration calorimetry (ITC), $^{15}N-HSQC$,\;and\;^{31}P-NMR$ revealed that neither its substrate nor inhibitor binds the isolated domain. The isolated domain maintained structural integrity, but did not function as the half of the full-length protein.

A Scanning Calorimetric Study of the Effect of Clover Saponin on Liposomal Phospholipid Membrane

  • Bae, Song-Ja;Han, Suk-Kyu;Im, Kwang-Sik;Kim, Nam-Hong
    • Archives of Pharmacal Research
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    • 제11권3호
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    • pp.181-184
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    • 1988
  • The effect of clover saponin on the phase transition of liposomal lipid bilayers of dimyristoyl phosphatidylcholine was investigated with differential scanning calorimetry. The thermograms of the liposomal bilayers incorporated with the clover saponin were obtained, and the enthalpy changes and the sizes of cooperative unit of the transition were calculated. The results showed that incorporation of the clover saponin into the liposomal bilayers effectively reduced the transition temperature at which the transition from solid state to liquid-crystalline state occurs, and broadened the thermogram peaks. It also reduced the size of cooperative unit of the transition. These results indicate that the clover saponin might have significant effect on the fluidity of biological membranes.

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LiBr와 CaBr2가 흡착된 알루미나상에서 일어나는 염화 알킬의 브롬화반응 (Bromination of Alkyl Chlorides by LiBr and CaBr2 adsorbed on Alumina)

  • 박영훈;신영문;조범준;김창배
    • 공업화학
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    • 제7권5호
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    • pp.1015-1019
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    • 1996
  • 알루미나에 LiBr와 $CaBr_2$를 각각 흡착시켜 용매가 없는 상태에서 여러 가지 염화 알킬과 반응시켜 좋은 수득률로 해당하는 브롬화 생성물을 얻을 수 있었다. 이러한 높은 반응성은 알루미나에 흡착되어 있는 극소량의 물과 브롬화 금속간의 상호작용이 알루미나 상에서 일어날 수 있기 때문이라는 것을 Differential scanning calorimetry (DSC) 열분석 실험과 문헌을 통하여 고찰하였다.

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종양 억제 인자, Merlin의 FERM 도메인과 C-말단 도메인간의 결합 (Interaction of FERM Domain of Tumor Suppressor, Merlin to its C-terminal Domain.)

  • 강범식;오정일
    • 생명과학회지
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    • 제17권9호통권89호
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    • pp.1303-1307
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    • 2007
  • A tumor suppressor, merlin is a member of ERM family proteins. It consists of N-terminal FERM domain, ${\alpha}-helical$ region, and C-terminal domain. Alternative splicing of merlin's mRNA generates two isotypes of merlin. Isotype I, which has exon17 at the C-terminus instead of exon16 in isotype II, is known to have tumor suppressor activity. Like other ERM proteins, the C-terminal domain of merlin isotype I interacts to its FERM domain. That of isotype II, however, was reported not to bind FERM domain despite the large common part of C-terminal domain, which possibly binds FERM domain. Here, we show the binding of FERM domain to both C-terminal domains of merlin's two isotypes by isothermal titration calorimetry. These results support that merlin isotype II also can form a closed conformation or a multimer by intramolecular or intermolecular interactions using their FERM domain and C-terminal domain.

Oxidation Stability of PAO Oils Determined by Differential Scanning Calorimetry

  • Shim, Joosup;Cho, Wonoh;Chung, Keunwo
    • Tribology and Lubricants
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    • 제12권1호
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    • pp.36-41
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    • 1996
  • The suitability of a pressure differential scanning calorimetry (PDSC) in monitoring the quality of synthetic base fluids has been investigated using polyalphaolefin (PAO) oils as an example. Induction period meassured at 170, 180 and 19$0^{\circ}C$, and 3.53 MPa oxygen pressure was applied to characterize their oxidation stability. The PDSC method has proven to be simple and repeatable and requires only small sample size for testing. More importantly, it can be applied in differentiating the oxidation performance quality of PAO oils and is versatile enough for use in studying kinetic aspects of PAO oil oxidation which include the effect of temperature and antioxidant concentration. Additionally, the method appears to correlate well with a rotary bomb oxidation test (RBOT).

시차주사열량분석을 이용한 배합성 연구 (Compatibility Study Using Differential Scanning Calorimetry)

  • 손영택;이애경
    • Journal of Pharmaceutical Investigation
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    • 제29권2호
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    • pp.117-126
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    • 1999
  • Differential scanning calorimetry(DSC) was used as a screening technique for assessing the compatibility of some drugs with excipients. On the basis of DSC results, interaction of ibuprofen with PVP K40 was found and eutectic formations with PEG 6000 or magnesium stearate were demonstrated. Fenoprofen Ca was found to interact with PEG 6000. Naproxen showed interactions with PEG 6000, PVP K40, PVPP and Mg stearate. Interactions of tiaprofenic acid with PVP K40 or PVPP were found and eutectic formations with PEG 6000 or Mg stearate were observed. Bisoprolol hemifumarate, metoprolol tartrate and penbutolol sulfate were found to interact with lactose.

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설파제의 다형(多形)에 관한 연구 (Study on the Polymorphism of Sulfa Drugs)

  • 손영택
    • Journal of Pharmaceutical Investigation
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    • 제20권1호
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    • pp.35-42
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    • 1990
  • A new form of sulfabenzamide was characterized using X-ray diffraction patterns and differential scanning calorimetry. Solubility studies demonstrated that, of the sulfabenzamide polymorphs, the new form was more soluble than form I. Compression of the new form at compression force of 1000 $kg/cm{^2}$ didn't induce polymorphic change in the crystal. Similar patterns were also produced through grinding. The effects of some diluents on the polymorphic transformation from the new form into form I by grinding and compression were also studied. Three diluents, $Avicel^{\circledR}$, lactose and starch showed no influence on the polymorphic transformation. The new form seemed to be more suitable for the pharmaceutical preparation.

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N,N,N-Tris-[4-(Naphthalen-1-yl-phenylamino)Phenyl]-N,N,N-Triphenylbenzene-1,3,5-Triamine을 이용한 Hole Transporting 재료의 합성 (Synthesis and Characterisation of Hole Transporting Materials Based on N,N,N-Tris-[4-(Naphthalen-1-yl-phenylamino)Phenyl]-N,N,N-Triphenylbenzene-1,3,5-Triamine)

  • Mathew, Siji;Haridas, Karickal R.
    • 대한화학회지
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    • 제54권6호
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    • pp.717-722
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    • 2010
  • Two derivatives of star shaped compounds based on naphthylamine benzene고리에 methoxy기와 ethoxy기가 치환기로 연결되어있는 naphthylamine 관련 화합물을 합성하였다. 합성한 화합물의 전자 및 열적특성을 cyclic voltametry (CV) 및 differential scanning calorimetry (DSC)를 이용하여 조사하였다.