• Title/Summary/Keyword: cross-linking

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Hydrophobic modification of PVDF hollow fiber membranes using polydimethylsiloxane for VMD process

  • Cui, Zhaoliang;Tong, Daqing;Li, Xue;Wang, Xiaozu;Wang, Zhaohui
    • Membrane and Water Treatment
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    • v.10 no.4
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    • pp.251-257
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    • 2019
  • Fabricating hydrophobic porous membrane is important for exploring the applications of membrane distillation (MD). In the present paper, poly(vinylidene fluoride) (PVDF) hollow fiber membrane was modified by coating polydimethylsiloxane (PDMS) on its surface. The effects of PDMS concentration, cross-linking temperature and cross-linking time on the performance of the composite membranes in a vacuum membrane distillation (VMD) process were investigated. It was found that the hydrophobicity and the VMD performance of the PVDF hollow fiber membrane were obviously improved by coating PDMS. The optimal PDMS concentration, cross-linking temperature and cross-linking time were 0.5 wt%, $80^{\circ}C$, and 9 hr, respectively.

Establishment of Reference Linking Systems on UCI Cross-Reference (UCI 상호참조에 기반한 참조연계시스템의 구현)

  • Park, Sungbum;Lee, Sangwon
    • Journal of Information Technology Services
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    • v.12 no.1
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    • pp.115-130
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    • 2013
  • This paper describes Cross reference services in Knowledge contents based on UCI. Cross references are effective features that can increase the value of the contents. Knowledge contents include academic papers, research reports, archives, historical and cultural heritage, and professional databases. Cross references are consists of reference-to and cited-by links which can be made by reference list in article. Some of cross reference services provided are considered. We designed cross reference services for knowledge contents in Korea and prototype services are provided. The reference linking service in the area of national R&D will enable the linking of heterogeneous information produced at different sources.

Investigation of Transglutaminase-Induced Peptide Cross-Linking by Matrix-Assisted Laser Desorption / Ionization Time-of-Flight Mass Spectrometry

  • 김희준;임효섭
    • Bulletin of the Korean Chemical Society
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    • v.20 no.11
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    • pp.1299-1302
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    • 1999
  • Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used to demonstrate cross-linking of peptides induced by transglutaminase. The presence of ε-( Υ-glutamyl)lysine isopeptide cross-link in the acid hydrolysate of the cross-linking reaction mixture was also demonstrated by MALDI-TOF-MS without prior separation. MALDI-TOF-MS quickly provided peptide mass maps after pronase digestion of the cross-linked peptide adduct, which enabled us to monitor the hydrolytic sequence. Pronase appears to preferentially hydrolyze peptide bonds distant from the cross-link before hydrolyzing peptide bonds around the cross-link. The results suggest that pronase digestion followed by MALDI-TOF-MS could be used for determination of amino acid sequence around a modification site.

Characteristics of Heat Curable Polyorganosiloxane Coating Materials (페닐기 함유 열경화성 폴리유기실록산 코팅제 특성)

  • Lee, Jin Hyouk;Kang, Doo Whan;Kang, Ho-Jong
    • Polymer(Korea)
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    • v.39 no.3
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    • pp.499-505
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    • 2015
  • Polyorganosiloxane having controlled cross-linking density and phenyl group content were prepared by dimethyldimethoxysilane (DMDMS), methyltrimethoxysilane (MTMS) and phenyltrimethoxysilane (PTMS). The effect of cross-linking density and phenyl group content on the physical properties of siloxane resin and its coated film have been invetigated. Si-NMR results confirmed that synthesized siloxane resins have equivalent D $T^{Me}$ $T^{Ph}$ structures according to applied mole ratios of DMDMS, MTMS and PTMS. Polyorganosiloxane having higher cross-linking density with high phenyl content showed the high molecular weight and increasing phenyl content resulted in higher refractive index as well as better thermal stability. Cross-linking density is more important factor than phenyl content to obtain higher pencil hardness of coated film on the glass. Our results concluded that even polyorganosiloxanes having similar siloxane structures show different physical properties as function of cross-linking density and phenyl content in polyorganosiloxane.

Inhibitory Effects of the Seeds of Cornus officinalis on AGEs Formation and AGEs-induced Protein Cross-linking (산수유 씨의 최종당화산물의 형성 및 교차결합에 미치는 효과)

  • Kim, Chan-Sik;Jang, Dae-Sik;Kim, Jung-Hyun;Lee, Ga-Young;Lee, Yun-Mi;Kim, Young-Sook;Kim, Jin-Sook
    • Korean Journal of Pharmacognosy
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    • v.39 no.3
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    • pp.249-254
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    • 2008
  • An 80% EtOH extract and the solvent fractions of the seeds of Cornus officinalis were evaluated for their inhibitory activities against advanced glycation end products (AGEs) formation and AGEs-induced protein cross-linking in vitro. In vitro assay for AGEs-bovine serum albumin (BSA) formation showed that the 80% EtOH extract, n-hexane, EtOAc, n-BuOH and water fractions significantly inhibited AGEs formation with observed $IC_{50}$ values of 1.13, 17.64, 1.52, 1.24 and $3.27{\mu}g/ml$, respectively. In indirect AGEs-ELISA assay, the 800% EtOH extract, EtOAc and n-BuOH fractions exhibited more potent inhibitory activity on AGEs-BSA formation than aminoguanidine, a well know AGEs inhibitor. Furthermore, the 80% EtOH extract and all the solvent fractions inhibited concentration-dependently AGE-BSA cross-linking to collagen. The 80% EtOH extract, EtOAc, n-BuOH and water fractions also had a breaking activity against preformed AGE-BSA cross-linking concentration dependently. Thus these results suggest that the 80% EtOH extract and fractions of the seeds of C. officinalis could be an inhibitor as well as breaker of AGE-BSA cross-linking.

Preparation and Electrochemical Applications of Pore-filled Ion-exchange Membranes with Well-adjusted Cross-linking Degrees: Part II. Reverse Electrodialysis (가교도가 조절된 세공충진 이온교환막의 제조 및 전기화학적 응용: Part II. 역 전기투석)

  • Song, Hyun-Bee;Moon, Ha-Neul;Kim, Do-Hyeong;Kang, Moon-Sung
    • Membrane Journal
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    • v.27 no.5
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    • pp.441-448
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    • 2017
  • In this study, the effects of membrane characteristics on the power generation performance in reverse electrodialysis (RED) have been investigated with pore-filled ion-exchange membranes (PFIEMs) prepared by employing a porous polyethylene substrate and the mixtures of three cross-linking agents. As a result, it was confirmed through the correlation analyses that the cross-linking degree and free volume of the PFIEMs were effectively controlled by mixing the cross-linking agents having different molecular sizes, influencing complexly the electrochemical characteristics of the membranes and the power generation performance in RED. In particular, the pore-filled cation-exchange membranes at the optimum cross-linking conditions exhibited the power generation performance superior to that of the commercial membranes and the pore-filled anion-exchange membranes also showed the excellent performance close to that of the commercial membrane.

Research and Development of Citation Matcher for Reference Parsing and Cross-Reference Linking (참고문헌 자동파싱 및 참조링킹을 위한 Citation Matcher 연구 및 개발)

  • Lee, Sang-gi;Kim, Sun-tae;Lee, Yong-sik;Yi, Tae-seok
    • Proceedings of the Korea Contents Association Conference
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    • 2007.11a
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    • pp.426-429
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    • 2007
  • CrossRef operates a cross-publisher citation linking system based on the DOI(R) global identifier. The number of organization building a reference citations linking structure through CrossRef is increasing. This paper concentrates on developing a Citation Matcher Solution to effectively build the reference linking structure. Citation Matcher automatically builds and processes the reference citation and identifier mapping which used to be handled manually. After the copy & paste of the reference citation, analyzation is processed to parse the journal title, author name, volume, issue, and start pages from the free style text. CrossRef, PubMed, and YesKISTI's identifiers are collected by through a standardized method. Renovation of the building process for domestic scholastic resources' reference linking and matching will be made possible by using a Citation Matcher. The connection between resources and seamless access for the electronic full-text will enhance the usability.

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Patterns of Citing Korean DOI Journals According to CrossRef's Cited-by Linking and a Local Journal Citation Database

  • Seo, Tae-Sul;Jung, Eun-Gyeong;Kim, Hwanmin
    • Journal of Information Science Theory and Practice
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    • v.1 no.2
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    • pp.58-68
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    • 2013
  • Citing literature is a very important activity for scholars in writing articles. Many publishers and libraries build citation databases and provide citation reports on scholarly journals. Cited-by linking is a service representing what an article cites and how many times it cites a specific article within a journal database. Recently, information services based on DOIs (Digital Object Identifiers) have been increasing in number. CrossRef, a non-profit organization for the DOI registration agency, maintains the DOI system and provides the cited-by linking service. Recently, the number of Korean journals adopting DOI is also rapidly increasing. The Korea Institute of Science and Technology Information (KISTI) supports Korean learned societies in DOI related activities in collaboration with CrossRef. This study analyzes cited patterns of Korean DOI journal articles using CrossRef's cited-by linking data and a Korean journal citation database. This analysis has been performed in terms of publication country and the language of journals citing Korean journal articles. The results show that DOI, SCI(E) (Science Citation Index (Expanded)), and English journals are more likely to be cited internationally.

Dexamethasone Release from Glutaraldehyde Cross-Linked Chitosan Microspheres: In Vitro/In Vivo Studies and Non-Clinical Parameters Response in Rat Arthritic Model

  • Dhanaraju, Magharla Dasaratha;Elizabeth, Sheela;Poovi, Ganesan
    • Journal of Pharmaceutical Investigation
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    • v.41 no.5
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    • pp.279-288
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    • 2011
  • The Dexamethasone (DEX) loaded chitosan microspheres were prepared by thermal denaturation and chemical cross-linking method using a dierent concentration of glutaraldehyde as chemical cross-linking agent. The prepared microspheres were evaluated for the percentage of Drug Loading (DL), Encapsulation Efficiency (EE) and surface morphology by Scanning Electron Microscopy (SEM). DL and EE were found to be maximum range of 10.0 to 10.79 % and 58.19 to 64.73 % respectively. The SEM Photographs of the resultant microspheres exhibited fairly smooth surfaces and predominantly spherical in appearance. In addition, Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) shown that there was no interaction between the drug and polymer. In vitro and in vivo release studies revealed that the release of dexamethasone was sustained and extended up to 63 days and effectively controlled by the extent of cross-linking agent. Non-clinical parameters such as paw volume, hematological parameters like Erythrocyte Sedimentation Rate (ESR), Paced Cell Volume (PCV), Total Leucocytes Count (TLC), Hemoglobin (Hb), Differential Cell Count (DCC) were investigated in Fruend's Complete Adjuvant (FCA) induced arthritic rats. Radiology and histopathological studies were also performed in order to evaluate the therapeutic efficacy of the DEX-loaded microspheres in extenuating the rat arthritic model.

Effects of Cross-Linking Agents on the Stability of Human Acellular Dermal Matrix (여러 가지 가교제가 인체 무세포진피의 안정성에 미치는 영향)

  • Kang, Nak Heon;Yun, Young Mook;Woo, Jong Seol;Ahn, Jae Hyung;Kim, Jin Young
    • Archives of Plastic Surgery
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    • v.35 no.3
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    • pp.248-254
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    • 2008
  • Purpose: Human acellular dermal matrix(ADM) is widely used in the treatment of congenital anomalies and soft tissue deficiencies. But it is rapidly degraded in the body and does not provide satisfactory results. There is a need to improve collagen fiber stability through various methods and ultimately regulate the speed of degradation. Methods: The ADMs were added with various cross-linking agents called glutaraldehyde, dimethyl 3,3'-dithiobispropionimidate to produce cross-linked acellular dermal matrices. 1,4-butanediol diglycidyl ether solution was applied with a pH of 4.5 and 9.0, respectively. The stability of cross-linked dermal matrix was observed by measuring the shrinkage temperature and the degradation rates. The cross- and non-cross linked dermis were placed in the rat abdomen and obtained after 8, 12 and 16 weeks. Results: The shrinkage temperature significantly increased and the degradation rate significantly decreased, compared to the control(p<0.05). All of cross-linked dermises were observed grossly in 16 weeks, but most of non-cross linked dermis were absorbed in 8 weeks. Histologically, the control group ADM was found to have been infiltrated with fibroblasts and most of dermal stroma were transformed into the host collagen fibers. However, infiltration of fibroblasts in the experiment was insignificant and the original collagen structure was intact. Conclusion: Collagen cross-linking increases the structural stability and decreases degradation of acellular dermis. Therefore, decrease in body absorption and increase in duration can be expected.