Papers by Keyword: Cyclodextrin

Abstract: This study concentrated on the preparation of lavender oil-β-cyclodextrin microcapsules using an optimized co-precipitation method. The impact of varying ethanol concentrations (20, 30, 40, 50% v/v) on encapsulation efficiency was extensively examined. The results showed that using β-cyclodextrin as the wall material at 40% ethanol concentration yielded a notably high encapsulation efficiency, with a microcapsule recovery rate of 86.46% and a lavender oil encapsulation rate of 72.64%. Additionally, when a β-cyclodextrin-maltodextrin combination was used as the wall material, the 40% ethanol concentration achieved a recovery rate of 78.20% and a lavender oil encapsulation rate of 61.12%. Morphological and X-ray diffraction analyses revealed structural changes in the crystals post-encapsulation, while Fourier Transform Infrared Spectroscopy (FTIR) confirmed the successful formation of the microcapsules.

Abstract: The jute and polypropylene fiber (PP) were formed into jute/PP composite by carding, netting and needling. Using surface dusting process, β-CD and ammonium phosphate (APP) were combined and hot pressed to form a flame-retardant layer on the surface of jute/PP composite. The results show that the thermal compression film formation on the surface of jute/PP composite after β-CD and APP compounding can significantly improve the flame retardancy and thermal stability of the jute/PP composite. When the mass ratio of β-CD to APP is 1:2 and keeping the 20wt% total content of the flame retardants, the jute/PP composite becomes extinguished after 58s combustion. The limiting oxygen index (LOI) value is 26.6%, which reaches the third fire resistance according to Japan's JISD 1201-77 standard. The heat release rate and effective combustion calorific show the lowest value and the carbon residual at 700°C is increased by 11. 68%.

Abstract: This work attempted to elucidate the corrosion inhibition mechanism of a supramolecular complex formed between β-cyclodextrin (β-CD) and octadecylamine (ODA) for mild steel in the condensate water. Molecular mechanics simulation was applied to determine the energy favored configuration of the complex and the possible orientation of ODA inside the β-CD cavity. Based on the results of gravimetric measurements, thermodynamics parameters for the adsorption process were calculated through Arrhenius and transition state equations. Scanning electron microscopy and X-ray photo electron spectroscopy were used for surface characterization. Density functional theory calculations (Mulliken charges and molecular electrostatic potential plot) were performed to clarify the adsorption mechanism of β-CD/ODA complex on the steel surface. It was found that four possible configurations of β-CD/ODA complex might be concurrent in the supramolecular system with the stable state in the aqueous solution. ODA molecules could break away from the β-CD cavity and chemically adsorbed on the metal surface, which obeyed the Langmuir adsorption isotherm. The inherent molecular electrostatic properties resulted in the tilted adsorption of ODA.

Abstract: Some gram-negative bacteria possess N-acylhomoserine lactone (AHL)-mediated quorum sensing (QS) as one of the cell-to-cell communication systems for regulation of various cell functions. Increase in the AHL concentration above its threshold leads to simultaneous activation of target gene expression in each cell. The AHL can diffuse in and out of the cells through the cell membrane. Artificial reduction of the AHL concentration can inhibit the AHL complex formation with its receptor inside the cell. In this study, the AHL that diffused out into the culture broth was captured on α-cyclodextrin (CD), which possesses a hydrophobic cavity and a hydrophilic shell. The α-CD-immobilized calcium alginate gel beads, which were prepared using a non-contact jet dispenser, were immersed in the culture medium during the cell growth of Serratia marcescens AS-1, which was used as the model opportunistic human pathogen. The trapping of AHLs on immobilized α-CDs due to hydrophobic interaction of the AHL acyl-chain led to an effective inhibition of AHL-mediated prodigiosin production to approximately 2% in the presence of 27 wt% gel beads in the culture broth. The results of our study suggest that CD has high potential to regulate QS involved in matter production, biofilm formation, and virulence factor expression.

Abstract: A amphiphilic triblock copolymer, poly(ethylene oxide) -poly(dimethylsiloxane) -poly(ethylene oxide) (PEO-PDMS-PEO) was synthesized via a simple hydrosilylation reaction, and inclusion selective rule of cyclodextrins (α–CDand γ-CD) and PEO-PDMS-PEO to form inclusion complexes were discussed in this paper. Selective inclusion's impact on the triblock copolymer( PEO-PDMS-PEO) was studied.

Abstract: In this study, the biotransformation which from cortisone acetate (CA) to prednisone acetate (PA) by Arthrobacter simplex (ASP) was selected as a model system for evaluating the effects of natural cyclodextrins (α-CD, β-CD and γ-CD, referred as CDs) on cell growth, dehydrogenase activity, permeability of Arthrobacter simplex. The results showed that the cavity size of cyclodextrins on ASP cell growth were quite different, the with smaller cavity significantly inhibited ASP growth. CDs reduced the dehydrogenase activity of ASP and increased the cell permeability. Initial conversion rate of cells after treated by CDs were higher than the control cells. The study provided basic datas for the application of cyclodextrin in the steroid biotransformation.

Abstract: Sr₄Al₁₄O₂₅:Eu²⁺, Dy³⁺ luminescent phosphor was synthesized for the first time from using cyclodextrin as chelating agent by sol-gel method. The structural characterization, surface morphology and properties of the phosphor were studied. The results revealed that the target phosphor with relatively regular morphology, smaller grain size, pure phase and high crystallinity can be achieved at 1200°C for 4 h in a reducing atmosphere. The average grain size of the Sr₄Al₁₄O₂₅:Eu²⁺, Dy³⁺ phosphor nanoparticles ranges from 50 to 100 nm . And the phosphorescence in blue-green (483 nm) by Eu²⁺.

Abstract: Microbial conversion is a key process in the biosynthetic routes of steroid medicine.The whole process of bioconversion includes two essential steps: (1) enzymatic reaction step where the enzyme-catalyzed substrate transformation takes place inside the cells, and (2) diffusion step that includes the diffusion of substrate molecules from the surface of solid substrate particles into bulk media (i.e., the solubilization of solid substrate), the diffusion of solubilized substrate molecules from bulk media into cells, and the diffusion of formed product molecules from inside cells into bulk media. In this review, the applications of three chemical factors (growth regulator,surfactant and cyclodextrin), and their effects on steroid microbial enzymatic conversion were extensively discussed, which provides insights into the development of novel approaches to cost-effectively improve biosynthesis efficiency in steroid medicine.

Abstract: TiO₂ nanoparticles were modified by β-cyclodextrin with crosslinking agent and characterized by X-ray diffraction (XRD) and infrared spectrum (IR spectrum). The X-ray diffraction examination showed that the crystal pattern of TiO₂ was not changed because of low-temperature during modification process. Analysis of IR spectrum showed that β-cyclodextrin was supported on surface of TiO₂ nanoparticles. The adsorption control experiment indicated β-cyclodextrin modification methods strongly enhanced adsorption capacity of TiO₂ for bisphenols A(BPA), because β-cyclodextrin which was on surface of nanoparticles increased the adsorption active sites of TiO₂.

Abstract: The photodegradation of 4,4-bis (4-hydroxyphenyl) pentanoic acid (DPA) with two cyclodextrins (α-CD and β-CD ) in aqueous solutions induced by UV-light was studied in this paper by means of fluorescence spectra and high efficiency liquid chromatography. The result suggested that DPA with α-CD or β-CD formed inclusion compound in aqueous solutions. The photodegradation of DPA with two cyclodextrins or without cyclodextrin was pseudo-first order reaction. The photodegradation of DPA was accelerated by the addition of β-CD in aqueous solutions, but the that of DPA was inhibited in case of adding α-CD. These differences were due to the differences in inclusion interaction of DPA with α-CD or β-CD.