Search results for "cellulose"
showing 10 items of 318 documents
Design, characterization and evaluation of hydroxyethylcellulose based novel regenerable supersorbent for heavy metal ions uptake and competitive ads…
2017
Abstract Hydroxyethylcellulose succinate-Na (HEC-Suc-Na) was designed and evaluated for removal of some heavy metal ions from aqueous solution. Pristine sorbent HEC-Suc-Na was thoroughly characterized by FTIR and solid-state CP/MAS 13C NMR spectroscopy, SEM-EDS and zero point charge analyses. Langmuir isotherm, pseudo second order kinetic and ion exchange models provided best fit to the experimental data of sorption of metal ions. Maximum sorption capacities of supersorbent HEC-Suc-Na for sorption of heavy metal ions from aqueous solution as calculated by Langmuir isotherm model were found to be 1000, 909.09, 666.6, 588 and 500 mg g−1 for Pb(II), Cr(VI), Co(II), Cu(II) and Ni(II), respectiv…
Immobilisation of yeasts on oak chips or cellulose powder for use in bottle-fermented sparkling wine
2019
[EN] Sparkling wine production comprises two successive fermentations performed by Sacharomyces cerevisiae strains. This research aimed to: develop yeast immobilisation processes on two wine-compatible supports; study the effects of yeast type (IOC 18-2007 and 55A) and the immobilisation support type (oak chips and cellulose powder) on the fermentation kinetics, the deposition rate of lees and the volatile composition of the finished sparkling wine; compare the fermentation parameters of the wines inoculated with immobilised or non-immobilised cells. Proper immobilisation of yeast on oak chips and cellulose powder was demonstrated by electron microscopy. Total sugar consumption occurred in …
Polyester vascular prostheses coated with a cyclodextrin polymer and activated with antibiotics: Cytotoxicity and microbiological evaluation
2008
Abstract Polyester (PET) vascular grafts are used to replace or bypass damaged arteries. To minimize the risk of infection during and after surgical interventions, a PET vascular prosthesis (Polythese®) was functionalized with cyclodextrin polymers (PolyCDs) in order to obtain the controlled release of antibiotics (ABs: ciprofloxacin, vancomcyin and rifampicin). An epithelial cell line (L132) was used to determine the viability of the antibiotics, and human pulmonary microvascular endothelial cells (HPMEC) were used for cell proliferation by cell counting and cell vitality with Alamar Blue fluorescent dye. Staphylococcus aureus, Escherichia coli and Enteroccocus sp. were used to determine t…
Hydroxypropylcellulose as a novel green reservoir for the synthesis, stabilization, and storage of silver nanoparticles
2015
Muhammad Ajaz Hussain,1 Abdullah Shah,1 Ibrahim Jantan,2 Muhammad Raza Shah,3 Muhammad Nawaz Tahir,4 Riaz Ahmad,5 Syed Nasir Abbas Bukhari2 1Department of Chemistry, University of Sargodha, Sargodha, Pakistan; 2Drug and Herbal Research Centre, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia; 3International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan; 4Institute of Inorganic and Analytical Chemistry, Johannes Guttenberg University, Duesbergweg, Mainz, Germany; 5Centre for Advanced Studies in Physics (CASP), GC University, Lahore, Pakistan Abstract: Polysaccharides are attracting the vigil eye of…
Polymer-enhanced ultrafiltration for heavy metal removal: Influence of chitosan and carboxymethyl cellulose on filtration performances
2018
Abstract Reclaiming of wastewaters contaminated by heavy metals has become a major challenge over the last decades. For this reason, nanoporous membrane processes have awaken the interest of industry and local community, and the possible ways to improve their performances has become a priority goal for researchers. Metal removal enhancement by polymer addition is a potential way that is deeply investigated herein on nickel ion rejection with chitosan and carboxymethyl cellulose addition. Due to the vanishing of electrostatic interactions induced by the large amount of salt usually contained in effluents, ion rejection consequently drastically drops. However, it is highlighted that a suffici…
Reversible stress softening and stress recovery of cellulose networks
2009
The mechanical properties of the plant cell wall play an important role in communication, differentiation and growth of plant cells. In particular, the expansive growth of plant cells is only possible because the material that forms the plant cell wall yields at a specific stress level, allowing for an increase in cell wall area. This process can be defined in mechanical terms as the relaxation of the wall stress. The current understanding of plant cell growth suggests that such relaxation behaviour occurs due to the presence of wall loosening agents rather than to the properties of the cellulose network itself. It is believed that certain nonenzymatic proteins, acting as wall loosening age…
Mechanistic Understanding of Food Effects: Water Diffusivity in Gastrointestinal Tract Is an Important Parameter for the Prediction of Disintegration…
2013
Much interest has been expressed in this work on the role of water diffusivity in the release media as a new parameter for predicting drug release. NMR was used to measure water diffusivity in different media varying in their osmolality and viscosity. Water self-diffusion coefficients in sucrose, sodium chloride, and polymeric hydroxypropyl methylcellulose (HPMC) solutions were correlated with water uptake, disintegration, and drug release rates from trospium chloride immediate release tablets. The water diffusivity in sucrose solutions was significantly reduced compared to polymeric HPMC and molecular sodium chloride solutions. Water diffusivity was found to be a function of sucrose concen…
Effective elastic properties of biocomposites using 3D computational homogenization and X-ray microcomputed tomography
2021
A 3D computational homogenization method based on X-ray microcomputed tomography (μCT) was proposed and implemented to investigate how the fiber weight fraction, orthotropy and orientation distribution affect the effective elastic properties of regenerated cellulose fiber-polylactic acid (PLA) biocomposites. Three-dimensional microstructures reconstructed by means of the X-ray μCT were used as the representative volume elements (RVEs) and incorporated into the finite element solver within the computational homogenization framework. The present method used Euclidean bipartite matching technique so as to eliminate the generation of artificial periodic boundaries and use the in-situ solution d…
Effect of Three Different Aloe vera Gel-Based Edible Coatings on the Quality of Fresh-Cut “Hayward” Kiwifruits
2020
In recent years, the market for minimally processed fruit has increased. Fresh-cut fruits are characterized by a short shelf life due to the processing phases that accelerate the ripening courses. The aim of this work is to analyze the effect on the quality of fresh-cut Hayward kiwis of three different edible coatings based on (1) Aloe vera gel, (2) Aloe vera gel + hydroxypropyl methylcellulose and (3) Aloe vera gel + lemon essential oil. Fruit firmness, weight loss, color, soluble solids content, titratable acidity, microbial load and sensory analysis were evaluated as fresh after 2, 4, 7 and 10 days. Aloe vera gel and Aloe vera gel + lemon essential oil maintained the best values, as they…
Reactivity of cellulose during hydrothermal carbonization of lignocellulosic biomass
2020
Abstract Hydrothermal carbonization (HTC) of pure cellulose (CE) and birchwood (BW) samples was carried out at temperatures between 160 and 280 °C, 0.5 h residence time and biomass-to-water ratio 1:5, to investigate the reactivity of cellulose in lignocellulosic biomass. Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) showed that the CE samples remained unaltered at temperatures up to 220 °C, but were significantly decomposed at 230 °C producing a thermal recalcitrant aromatic and high energy-dense material. FTIR showed that dehydration and aromatization reactions occurred at temperature equal or higher than 230 °C for the CE samples while a similar incre…