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1.
Pakavadee Ratanajiajaroen Anyarat Watthanaphanit Hiroshi Tamura Seiichi Tokura Ratana Rujiravanit 《European Polymer Journal》2012,48(3):512-523
β-Chitin sheets containing curcumin—a naturally occurring substance that possesses several advantages biological properties including antioxidant, antimicrobial, and anti-inflammatory activities—were fabricated by the paper-making process using a water-based system. Using the chitin matrix consisting of small fibers could give rise to a large surface area that could improve the diffusion of solvent and reagent, so as to make the material suitable for use as support and carrier for drugs. Tween 20 was used as an emulsifier to improve water solubility of the curcumin. The change in surface morphology of the fabricated chitin sheets after curcumin loading was indicated by scanning electron microscope (SEM). A rough surface consisting of fibrous chitin could be seen both on the neat chitin sheets and the curcumin-loaded chitin sheets, while the increase in the curcumin content led the sheets to show an occurrence of spots. Investigation of the release behavior of the curcumin loaded into the chitin sheet was carried out by the total immersion method in an acetate buffer solution, pH 5.5, at 37 °C (simulating human skin). It was found that the amounts of loaded curcumin affected the release characteristics of the curcumin from the chitin sheet as a function of releasing time. In addition, the Tween 20 played an important role in the release ability of the curcumin to an exterior solution and in the stability of the curcumin present in the chitin sheet. It could be postulated that the water solubility, release ability, and stability of the curcumin incorporated into the β-chitin sheets was improved by the inclusion of curcumin into the cores of the Tween 20 micelles and the β-chitin non-woven fibrous sheet containing curcumin could be a promising candidate for would care materials. 相似文献
2.
Ratana Seangprasertkij Zouhair Asfari Jacques Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》1994,17(2):111-118
Di-aza-benzo crown etherp-tert-butyl calix[4]arene (1) has been prepared by hydrogenating the already known Schiff-base precursor (2). The metal ion complexing ability of (1) toward zinc cation is presented. The formation of a 2:1 (Zn: (1) complex and the location of zinc cations were deduced from1H-NMR investigations. 相似文献
3.
Ratana Seangprasertkij Zouhair Asfari Françoise Arnaud Jean Weiss Jacques Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》1992,14(2):141-147
This communication describes the synthesis of Schiff base calix[4]arene (1) in which the Schiff base unit bridges two opposite hydroxy groups ofp-tert-butylcalix[4]arene. The synthesis of (1) has been achieved by refluxing in acetonitrile-methanol the appropriate 1,3-dicarbaldehyde-p-tert-butyl-calix[4]arene (4) with 1,3-diaminopropane. The yield of the reaction is 19%. Ligand (1) possesses a compartment containing two nitrogen atoms, four ether-type oxygen atoms, and two ionizable hydroxy groups likely to complex metal cations. 相似文献
4.
Porntip Luangrujiwong Anawat Sungpet Ratana Jiraratananon J. Douglas Way 《Journal of membrane science》2005,250(1-2):277-282
Single-component facilitated transports of ethylbenzene, styrene, cyclohexene and 1-hexene were carried out using the feed concentrations ranging from 0.5 M to pure. Equilibrium constants of the Ag+-solute complex formation, determined by distribution method, were 0.7, 2.2, 32.0, 129.1 M−1, respectively. Carrier saturation was not found with the membrane incorporated with 2.67 M Ag+-ion. As the carrier concentration was reduced to 0.51 M, increase in the feed concentration beyond 4.5 M had very little effect on ethylbenzene flux, suggesting the onset of carrier saturation. Styrene and cyclohexene underwent the carrier saturation when the carrier loading was 0.25 M, while a complete saturation was not observed with 1-hexene. Extraction of solute from the membranes revealed that less than 50% of Ag+-ions were occupied when the carrier saturation occurred. It was also found that the ability of solute to use available Ag+-ions in the membrane was dependent on the equilibrium constant. 相似文献
5.
A combined osmotic pressure and cake filtration model for crossflow nanofiltration of natural organic matter (NOM) was developed and successfully used to determine model parameters (i.e. permeability reduction factor (η) and specific cake resistance (αcake)) for salt concentrations, NOM concentrations, and ionic strength of salt species (Na+ and Ca++). In the absence of NOM, with increasing salt concentration from 0.004 to 0.1 M, permeability reduction factor (η)) decreased from 0.99 to 0.72 and 0.94 to 0.44 for monovalent cation (Na+) and divalent cation (Ca++), respectively. This reduced membrane permeability was due to salt concentrations and salt species. In the presence of NOM, specific cake resistance tended to increase with increasing NOM concentration and ionic strength in the range of 0.85 × 1015–3.66 × 1015 m kg−1. Solutions containing divalent cation exhibited higher normalized flux decline (Jv/Jvo = 0.685–0.632) and specific cake resistance (αcake = 2.89 × 1015–6.24 × 1015 m kg−1) than those containing monovalent cation, indicating a highly compacted NOM accumulation, thus increased permeate flow resistance during NF filtration experiments. After membrane cleaning, divalent cation exhibited lower water flux recovery than monovalent cation, suggesting higher non-recoverable (Rnon-rec) resistance than monovalent cation. 相似文献
6.
A new combination bismuth bulk electrode allowing potentiostatic control to be maintained in a suspended sample drop is described. The electrode was tested by adsorptive constant‐current stripping chronopotentiometry for iron(III) using Solochrome Violet RS. Optimum conditions were similar to those established with mercury‐based electrodes. With an electropolishing scheme, a reproducibility better than 2 % (n=54) was attainable. The limit of detection was 0.6 µg L?1 in deoxygenated samples. A partial least squares calibration gave a result of 972±78 µg L?1 (95 %, n=5) for a 1000±5 µg L?1 iron reference solution. 相似文献
7.
Thanawit Pothsree Ratana Seangprasertkij-Magee Thawatchai Tuntulani 《Journal of inclusion phenomena and macrocyclic chemistry》1997,29(2):99-107
A novel compound, 25, 27 - N,N - di - ((2 -ethoxy)benzyl)butylenediamine - p - tert- butylcalix[4]arene, 1, has beensynthesized by reducing its Schiff base derivative. Inclusion studies by1H-NMR spectroscopy in a mixed solvent (CD3OD/CDCl3) of25,27-N,N-di-((2-ethoxy)benzyl)propylenediamine-p-tert-butylcalix[4]arene,2, and 1 with Zn(II) ions, where counter anions are Cl-, Br-, I- and NO
3
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,show that both ligands can bind Zn(II) to a different extent depending onthe counter anions and the cavity size of the ligands. The stabilityconstants of ZnX2–1 (ZnX2-2) complexes where X = Cl-, Br-, I- and NO
3
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are 1.4 ± 0.1 (1.6 ± 0.1), 1.7 ± 0.1 (1.9 ±0.1), 2.2 ± 0.1 (2.7 ± 0.1) and 4.7 ± 0.1 (6.0 ±0.1), respectively. The calix[4]arene unit of the ligand 2 was found to havea structural change from cone to partial cone conformation upon binding toZnCl2, ZnBr2 and ZnI2. 相似文献
8.
Wongpanit P Sanchavanakit N Pavasant P Supaphol P Tokura S Rujiravanit R 《Macromolecular bioscience》2005,5(10):1001-1012
CM-chitin and CM-chitosan films were successfully crosslinked by microwave treatment. Crosslinking of the microwave-treated CM-chitin films involved mainly the carboxylate and the secondary alcohol groups, while crosslinking of microwave-treated CM-chitosan films involved the carboxylate and the amino groups. In addition, the crystallinity of CM-chitin increased with increasing microwave treatment time, whereas an increase in the crystallinity of the microwave-treated CM-chitosan films was not observed. At a similar percentage of weight loss, the crosslinking of either CM-chitin or CM-chitosan films by microwave treatment required much less stringent condition when compared with the crosslinking by autoclave treatment. Based on both direct and indirect cytotoxicity assays, the cytotoxicity of the microwave-treated CM-chitin films was negative, while that of the microwave-treated CM-chitosan films was positive. Human fibroblasts adhered on the surface of microwave-treated CM-chitosan films much better than on the surface of microwave-treated CM-chitin films. 相似文献
9.
Sakkawet Yorsaeng Orathai Pornsunthorntawee Ratana Rujiravanit 《Plasma Chemistry and Plasma Processing》2012,32(6):1275-1292
The natural rubber latex (NRL) film taken from medical surgical gloves was surface-modified with a dielectric barrier discharge (DBD) plasma treatment under an air environment. The results showed that surface hydrophilicity of the NRL film increased after the plasma treatment due to the presence of oxygen-containing polar groups on the plasma-treated surface. An increase in plasma treatment time increased the surface roughness of the NRL film, and eventually decreased the mechanical properties. From the obtained results, the optimum plasma treatment time of 20?s was chosen. After immersion in a chitosan solution, the amount of chitosan deposited on the plasma-treated NRL film increased with increasing chitosan concentrations. The chitosan coating smoothed the surface of the plasma-treated NRL film and also improved the mechanical properties. The highest antibacterial activities of the chitosan-coated DBD plasma-treated NRL film against both Staphylococcus aureus and Escherichia coli were achieved when a 2?%(w/v) chitosan solution was used for the coating. 相似文献
10.
Surakerk Onsuratoom Ratana Rujiravanit Thammanoon Sreethawong Seiichi Tokura Sumaeth Chavadej 《Plasma Chemistry and Plasma Processing》2010,30(1):191-206
In this work, the hydrophilic improvement of a woven PET surface was accomplished by a plasma technique. The woven PET surface
was plasma-treated by dielectric barrier discharge (DBD) under various operating conditions (electrode gap distance, plasma
treatment time, input voltage, and input frequency) and various gaseous environments (air, O2, N2, and Ar) in order to improve its hydrophilicity. It was experimentally found that a decrease in electrode gap distance and
an increase in input voltage increased the electric field strength, leading to higher hydrophilicity of the PET surface characterized
by wickability and contact angle measurements. In comparisons among the studied environmental gases, air gave the highest
hydrophilicity, being comparable to O2, while Ar and N2 gave lower hydrophilicity of the woven PET surface. The optimum conditions for a maximum hydrophilicity of the PET surface
were an electrode gap distance of 4 mm, a plasma treatment time of 10 s, an output voltage of 15 kV, and a frequency of 350 Hz
under air environment. After the plasma treatment under the obtained optimum conditions, the woven PET was loaded with Ag
particles using a AgNO3 aqueous solution in order to obtain the antimicrobial property. The plasma-treated woven PET loaded with Ag particles exhibited
good antimicrobial activity against both E. coli (gram-negative bacteria) and S. aureus (gram-positive bacteria). 相似文献