Search

Your search keyword '"Zhai, Maolin"' showing total 615 results
Start Over Author "Zhai, Maolin"
615 results on '"Zhai, Maolin"'

201. Radiation preparation and diffusion behavior of thermally reversible hydrogels

Author

Zhai Maolin, Yi Min, Wei Jinshan, Shu Jian, and Ha Hongfei

Subjects
Radiation, Ternary numeral system, Aqueous solution, Chemistry, technology, industry, and agriculture, macromolecular substances, complex mixtures, Lower critical solution temperature, chemistry.chemical_compound, Monomer, Chemical engineering, Self-healing hydrogels, Polymer chemistry, medicine, Binary system, Swelling, medicine.symptom, Drug carrier
Abstract

Temperature sensitive PolyNIPAAm hydrogels in the form of rod were prepared from the binary system of NIPAAm/water and ternary system of NIPAAm/Bis/water by γ-irradiation with 60 Co source at room temperature, respectively. The prepared hydrogels had obvious temperature sensitivity (LCST is about 35.0 °C) and suitable mechanical properties. The incorporation of cross-linking agent, N, N′-methylene-bisacrylamide (Bis), into the binary system of monomer/water reduced the gelation dose. The maximum swelling ratio of hydrogels was decreased with the increasing of dose or the incorporation of Bis. The diffusion behavior of water in hydrogels obtained in this work was investigated. In addition, the drug delivery of fluoro uracili (Fu-5) from the hydrogels was investigated.

Published
1998
Full Text
View/download PDF

202. Extraction performance of Eu3+ by using heterocyclic N-donor ligands with different structures in ionic liquids: an experimental and theoretical study.

Author

Wang, Yue, Ao, Yinyong, Yuan, Weijin, Peng, Jing, Zhao, Long, and Zhai, Maolin

Subjects
HETEROCYCLIC compounds, LIGANDS (Chemistry), IONIC liquids
Abstract

The extraction performance of 2,6-bis(5,6-diisobutyl-1,2,4-triazin-3-yl)pyridine (isobutyl-BTP), 2,6-bis(5,9,9-trimethyl-5,6,7,8-tetrahydro-5,8-methanobenzo[1,2,4]triazin-3-yl)pyridine (CA-BTP) and 2,9-bis(5,9,9-trimethyl-5,6,7,8-tetrahydro-5,8-methanobenzo[1,2,4]triazin-3-yl)-1,10-phenanthroline (CA-BTPhen) in combination with 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]) in the presence of nitric acid was investigated by using Eu3+ as the model ion, which has similar properties to trivalent actinides. It was found that both nitric acid and the structure of heterocyclic N-donor ligands have influence on the extraction performance of Eu3+. With the increment of nitric acid concentration, the dominant extraction mechanism varies from the cation exchange mechanism to the neutral complex mechanism. Isobutyl-BTP has the fastest extraction rate, and CA-BTPhen has the highest extraction ratio both under neutral conditions and at 0.01 M nitric acid. DFT calculations demonstrated that the protonation and conformational change of heterocyclic N-donor ligands are related to their structure, which further influence the structure and migration of extracted species during extraction. During the extraction process, heterocyclic N-donor ligands prefer to migrate to the aqueous phase and form a complex with Eu3+, and then the coordination complexes migrate back to the ionic liquid phase. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

203. Radiation synthesis of a water-soluble temperature sensitive polymer, activated copolymer and applications in immobilization of proteins

Author

Wu Jilan, Zhai Maolin, and Ha Hongfei

Subjects
chemistry.chemical_classification, Radiation, Aqueous solution, Immobilized enzyme, Polymerization, chemistry, Chemical engineering, Yield (chemistry), Polymer chemistry, Copolymer, Thermal stability, Polymer, Lower critical solution temperature
Abstract

In this work the radiation polymerization of N-isopropylacrylamide (NIPAAM) in aqueous solutions has been carried out and a water-soluble, temperature sensitive polymer and copolymer were obtained by using γ-rays from Co-60 source at room temperature. We have gained the optimum dose and dose—rate of radiation synthesis of linear polyNIPAAM through determining conversion yield and viscosity. In order to immobilize protein (BSA) and enzyme (HRP) into this water-soluble polymer, we prepared an activated copolymer, poly ( N-isopropylacrylamide-co-N-acryloxysuccinimide). The BSA and HRP has been immobilized onto the activated copolymer. The BSA (HRP) / copolymer conjugates still kept the original thermally sensitive properties of the linear polyNIPAAM. The conjugation yield of BSA to the activated copolymer decreased with increasing of dose. The thermal stability of the immobilized HRP was stable at 0 °C for a long time and has, at least, 4 days stability at room temperature. Immobilized HRP activity was lowered when the temperature was raised above its LCST. This phenomenon was reversible and the immobilized HRP regained activity below its LCST. The optimum pH of the immobilized HRP shifted from ca.5 upward to ca.7.

Published
1993
Full Text
View/download PDF

216. Radiation degradation of microcrystalline cellulose in solid status

Author

Sun, Jian, Xu, Ling, Ge, Mengyi, Zhai, Maolin, Sun, Jian, Xu, Ling, Ge, Mengyi, and Zhai, Maolin

Abstract

Pulverization and degradation are important pretreatment procedures in producing bio-ethanol from cellulose. In this study, microcrystalline cellulose (MCC), a pure alpha-cellulose, was degraded by gamma-irradiation. The average degree of polymerization, content of reducing sugar, crystalline structure, and molecular structure were investigated to elucidate the radiation effect on the degradation of MCC. The results manifested that gamma-ray destroyed part of the chemical bond and hydrogen bond, leading to the degradation of cellulose and increasing of the reducing sugar content. According to the Fourier transform infrared result, radiation degradation led to the formation of reductive carbonyl group. Meanwhile, radiation had slight influence on the crystalline structures of MCC. Therefore, the radiation degradation procedure is expected to benefit the further proceedings such as ultrafine treatment and enzyme hydrolysis of cellulose. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 1630-1636, 2013

Published
2013

217. Structural study and preliminary biological evaluation on the collagen hydrogel crosslinked by γ-irradiation

Author

Zhang, Xiangmei, Xu, Ling, Huang, Xin, Wei, Shicheng, Zhai, Maolin, Zhang, Xiangmei, Xu, Ling, Huang, Xin, Wei, Shicheng, and Zhai, Maolin

Abstract

Under ?-irradiation, concentrated collagen solutions yielded collagen hydrogels and liquid products. The molecular structure of collagen hydrogels and the source of the liquid products were studied. Furthermore, preliminary biological properties of the hydrogels were investigated. The results revealed that crosslinking occurred to form collagen hydrogel and the crosslinking density increased with the increasing of the absorbed dose, and the collagen hydrogels showed enhanced mechanical properties. Meanwhile, collagen underwent radiation degradation and water was squeezed out from hydrogel by contraction of hydrogel, yielding liquid products. Collagen hydrogels induced by ?-irradiation maintained the backbone structure of collagen, and tyrosine partially involved in crosslinking. The irradiated collagen hydrogels have higher denatured temperature, can promote fibroblasts proliferation, and their degradation rate in vivo depended on the absorbed dose. The comprehensive results suggested that the collagen hydrogels prepared by radiation crosslinking preserved the triple helical conformation, possessed improved thermal stability and mechanical properties, excellent biocompatibility, which is expected to favor its application as biomaterials. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:29602969, 2012.

Published
2012

Catalog

Books, media, physical & digital resources
See catalog results