• Title/Summary/Keyword: cross-linking agents

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Effect of Plasticizer and Cross-Linking Agent on the Physical Properties of Protein Films

  • Lee, Myoung-Suk;Lee, Se-Hee;Ma, Yu-Hyun;Park, Sang-Kyu;Bae, Dong-Ho;Ha, Sang-Do;Song, Kyung-Bin
    • Preventive Nutrition and Food Science
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    • v.10 no.1
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    • pp.88-91
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    • 2005
  • To improve the physical properties of protein films, various plasticizers and cross-linking agents were used in the preparation of the films. For zein film, 3% polypropylene glycol with 3% glycerol was the best plasticizer, while 2.5% glycerol was the most suitable for soy protein isolate (SPI) film in terms of tensile strength (TS), % elongation, and water vapor permeability (WVP). Formaldehyde, glutaraldehyde, glyoxal, and cinnamaldehyde as cross-linking agents of protein films were used to further improve the physical properties of the films. All aldehydes used as cross-linking agent in this study improved TS of zein and SPI films. In particular, cinnamaldehyde was the best cross-linking agent due to its safety in foods. These results suggest that appropriate use of plasticizer and cross-linking agent like cinnamaldehyde should improve the physical properties of protein films for use in food packaging.

Effect of cross-linking agents on the properties of copolyetherester elastomer(II) (코폴리에테르에스테르 고무 탄성체의 물성에 미치는 가교제의 효과(II))

  • Jang, Young-Joo;Kim, Hae-Young;Baik, Doo-Hyun
    • Proceedings of the Korean Fiber Society Conference
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    • 2002.04a
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    • pp.301-304
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    • 2002
  • In the prior work,$\^$l)/ we introduced several chemical cross-linking agents in order to improve elastic recovery of copolyetheresters, but we are confronted by two difficulties. The first is that cross-linking agents interfere with crystal growth which acts as a physical interlocking. The second is that strain at breaking decreases with the amount of cross-linking agent. It is considered that the chemical interlocking parts couldn't be deformed like crystalline phase. (omitted)

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Effect of Cross-Linking Agents on L-Sorbose Production by Immobilized Gluconobacter suboxydans Cells

  • PARK, YOUNG-MIN;SANG-KI RHEE;EUI-SUNG CHOI;IN SIK CHUNG
    • Journal of Microbiology and Biotechnology
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    • v.8 no.6
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    • pp.696-699
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    • 1998
  • Biological oxidation of D-sorbitol to L-sorbose using permeated and immobilized cells of Gluconobacter suboxydans was carried out to investigate the optimum reaction condition. The stabilization effect of cross-linking agents such as glutaraldehyde, tannic acid, and polyethylene imine to prevent the leakage of enzymes from beads containing permeated and immobilized cells of G. suboxydans was examined by the production of L-sorbose from the mixture of D-sorbitol and gluconic acid. The protein concentration effused from immobilized beads treated with only glutaraldehyde was $5.2\mug/m\ell$ after 20 h. The beads of G. suboxydans immobilized with alginate and cross-linked with 0.3% glutaraldehyde was the most useful for the oxidation of D-sorbitol to L-sorbose.

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Cross-Linked Starch Microspheres: Effect of Cross-Linking Condition on the Microsphere Characteristics

  • Atyabi, Fatemeh;Manoochehri, Saeed;Moghadam, Shadi H.;Dinarvand, Rassoul
    • Archives of Pharmacal Research
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    • v.29 no.12
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    • pp.1179-1186
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    • 2006
  • Cross-linked starch microspheres were prepared using different kinds of cross-linking agents. The influence of several parameters on morphology, size, swelling ratio and drug release rate from these microspheres were evaluated. These parameters included cross-linker type, concentration and the duration of cross-linking reaction. Microspheres cross-linked with glutaraldehyde had smooth surface compared with those prepared with epichlorhydrine or formaldehyde. The particle size increased with increasing the cross-linking time and increasing the drug loading. Swelling ratio of the particles was a function of cross-linker type but not the concentration or time of cross-linking. Drug release from starch microspheres was measured in phosphate buffer and also in phosphate buffer containing a-amylase. Results showed that microspheres cross-linked with epichlorhydrine released all their drug content in the first 30 minutes. However, cross-linking of the starch microspheres with glutaraldehyde or formaldehyde decreased drug release rate. SEM and drug release studies showed that cross-linked starch microspheres were susceptible to the enzymatic degradation under the influence of alpha-amylase. Changing the enzyme concentration from 5000 to 10,000 IU/L, increased drug release rate but higher concentration of enzyme (20,000 IU/L) caused no more acceleration.

Is dentin biomodification with collagen cross-linking agents effective for improving dentin adhesion? A systematic review and meta-analysis

  • Julianne Coelho Silva;Edson Luiz Cetira Filho;Paulo Goberlanio de Barros Silva;Fabio Wildson Gurgel Costa;Vicente de Paulo Aragao Saboia
    • Restorative Dentistry and Endodontics
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    • v.47 no.2
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    • pp.23.1-23.18
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    • 2022
  • Objectives: The aim of this investigation was to evaluate the effectiveness of collagen cross-linking agents (CCLAs) used in combination with the adhesive technique in restorative procedures. Materials and Methods: In this systematic review, the authors followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. An electronic search was performed using PubMed, Scopus, Web of Science, Cochrane Library, LILACS, and DOSS, up to October 2020. The gray literature was also researched. Only randomized clinical trials were selected. Results: The selection process yielded 3 studies from the 838 retrieved. The addition of CCLAs in the retention of restorations increased the number of events. The postoperative sensitivity scores and marginal adaptation scores showed no significant difference between the CCLA and control groups, and the marginal pigmentation scores showed a significant increase in the CCLA group. There were no caries events in any group throughout the evaluation period. Conclusions: This systematic review showed that there is no clinical efficacy to justify the use of CCLAs in the protocols performed.

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.

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.

Characteristics of Soybean Protein Resin Modified by Plasticizers and Cross-Linking Agents (가소제 및 가교제에 의해 개질된 대두단백질의 특성)

  • Choi, Han Na;Lee, Tae Sang;Yang, Ji Woo;Lee, Seung Goo
    • Journal of Adhesion and Interface
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    • v.12 no.2
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    • pp.73-80
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    • 2011
  • In order to develop the environmental-friendly new materials based on soybean protein which is plantable macromolecule, thermal characteristics of the soybean protein resin (SPI) modified by plasticizers (1,3-propandiol, glycerol) and cross linking agents (glutaraldehyde, epichlorohydrin, glyoxal, urea) were analyzed by TGA. Mechanical properties of modified SPI were investigated and fracture was observed by SEM. As the result, flexibility of SPI film was increased by adding plasticizers; 1,3-propandiol and glycerol. Plasticization effect of glycerol was relatively greater than that of 1,3-propandiol. With the application of crosslinking agents (glycerol, epichlorohydrin and glyoxal), strength and thermal stability of SPI increased with their content. On the other hand, in case of addition of urea, thermal stability of SPI decreased and its strength was reduced because cross-linking between urea and SPI was somewhat difficult. Fracture surfaces and domain interfaces of the modified SPI resins were observed with SEM.

A New Coloured Substrate for the Determination of $\beta$-Glucan Degrading Enzyme from Malt and Bacillus subtilis K-4-3 (맥아와 Bacillus subtilis B-4-3의 $\beta$-Glucan 분해 효소측정을 위한 새로운 색소기질)

  • 이성택
    • Microbiology and Biotechnology Letters
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    • v.16 no.2
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    • pp.79-84
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    • 1988
  • Dye materials and cross linking agents were used for the determination of $\beta$-glucanase activities. The objective of this study was to prepare the blue coloured substrates which are sensitive, specific and simple for the determination of $\beta$-glucanase in malt and Bacillus subtilis K-4-3 enzymes. This method is based on the principle of measuring colorimetrically the split product of coloured and cross linked substrate. The best coupling of dye stuff of $\beta$-glucan was cibacron blue 3G-A and the colour released can suitably be measured at 623nm. Optimal concentration of dye and cross linking agents was 1.5g and 1.25$m\ell$ under 0.1N NaOH. The sensitivity comparison proved that the stained $\beta$-glucan method is much more sensitive than the DNS method to determine reducing sugar released by the enzyme.

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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.