Search results for "Cellulose"
showing 10 items of 318 documents
Effect of unbalanced diets on incorporation of δ-aminolevulinic acid into cytochrome P-450
1987
Abstract The in vivo syntheses of two liver microsomal cytochromes P-450 PB 3a , P-450 UT 50 [(1987) Eur. J. Biochem., submitted] ( M r 50 000, 52 000) have been estimated by measuring the specific activity 2 h after i.p. administration of δ-[ 3 H]aminolevulinic acid to male Sprague Dawley rats. The animals were fed either a standard rat chow (5% lard, 22% casein) or unbalanced diets (high lipid, 30% lard or low protein, 6% casein) with or without 50 ppm Phenoclor DP6. The high-lipid diet supported a more rapid body weight gain but had little impact on cytochrome P-450 content, expressed either per whole liver or per mg microsomal protein, and on the incorporation of the precursor into cyto…
Arthus type inflammation with rat immunoglobulins.
1971
Etude comparative des proprietes biologiques des anticorps IgM, IgG1 et IgG2 du rat. Les resultats montrent que le pouvoir agglutinant et lytique des anticorps IgM est respectivement 37 et 100 fois superieur a celui des deux classes d'anticorps IgG. Par contre, en ce qui concerne le phenomene d'Arthus, les anticorps IgM sont moins actifs que les anticorps IgG, si les rapports sont exprimes en poids. Si l'on calcule les rapports par nombre de molecules, les anticorps IgM sont aussi, dans ce cas, plus actifs que les IgG.
Extended release and enhanced bioavailability of moxifloxacin conjugated with hydrophilic cellulose ethers.
2015
Macromolecular prodrugs (MPDs) of moxifloxacin were fabricated based on hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC). UV/Vis spectrophotometry was employed to determine covalently loaded drug content (DC) of each conjugate. The degree of substitution (DS) of moxifloxacin attained ranged from 0.27 to 0.38 (HPC) and 0.19 to 0.26 (HEC) per anhydroglucose unit (AGU), respectively. Transmission electron microscopic analyses showed that HPC-moxifloxacin conjugates self-assembled into nanowires of ∼ 30 nm diameters while HEC-moxifloxacin conjugates self-assembled into nanoparticles of 150-350 nm. In vitro drug release studies revealed that 15 and 49% moxifloxacin release occurred f…
The use of haemostatic agents in thyroid surgery: efficacy and further advantages. Collagen-Fibrinogen-Thrombin Patch (CFTP) versus Cellulose Gauze.
2013
Abstract Aim: To assess the efficacy of two widely used topical haemostatic agents: oxidised regenerated cellulose gauze and Collagen-Fibrinogen-Thrombin Patch in patients undergoing total thyroidectomy. Material of study: This was a prospective, comparative, non-randomised study in which consecutive patients undergoing total thyroidectomy for benign disease received standard treatment with no haemostatic agent, cellulose gauze, or CFTP. Main outcome measures were drainage volume 24 hours after surgical procedure and the occurrence of post-operative complications (haematoma, seroma, surgical-site infection). Results: Two hundred seventy-one (271) patients undergoing total thyroidectomy for …
Hydrothermal liquefaction of wood using a modified multistage shrinking-core model
2020
Abstract Wood liquefaction in hot compressed water is modeled using the hydrolysis of Cellulose, Hemicellulose, and Lignin. These three components are reacted under catalyst-free subcritical conditions in a temperature range from 553 K to 640 K, and the heating rate ranges from 2 K/min to 6 K/min. Using a simplified reaction scheme, water-soluble products 1 (WSP), Biocrude, char, and gas are generated through intermediates with each wood component. A modified multistage shrinking core model is employed to simulate biomass particle degradation. The reaction and kinetic regime of the hydrothermal liquefaction 2 (HTL) process are treated separately for each wood component. Although the lack of…
Halloysite Nanotubes: Interfacial Properties and Applications in Cultural Heritage
2020
The peculiar surfaces of halloysite nanotubes and their biocompatibility are attracting the interest of researchers based on the wide range of attainable applications. The large aspect ratio of this nanotubular material ensures promising properties as a reinforcing agent in polymeric matrixes, such as cellulose and its derivatives, that entail strengthening due to, for instance, aging-induced degradation. The halloysite cavity has a suitable size for hosting a large variety of active species such as deacidifying (calcium hydroxide) and flame retardant agents (fluorinated surfactants) for a controlled and sustained release relevant to the conservation of cultural heritage. Additionally, anio…
Biopolymer-Targeted Adsorption onto Halloysite Nanotubes in Aqueous Media.
2017
Studies on the adsorption of biopolymers onto halloysite nanotubes (HNTs) in water were conducted. Three polymers with different charges-anionic (pectin), neutral (hydroxypropyl cellulose), and cationic (chitosan)-were chosen. The thermodynamic parameters for the adsorption of polymers onto the HNT surface were determined by isothermal titration calorimetry (ITC). The experimental data were interpreted based on a Langmuir adsorption model. The standard variations in free energy, enthalpy, and entropy of the process were obtained and discussed. Turbidimetry was used to evaluate the stability of functionalized nanoparticles in water. The ζ-potential clarified the surface charge properties of …
Performance of Multilayered Particles: Influence of a Thin Cushioning Layer
2005
Nowadays, oral dosage forms with controlled release kinetics have known an increasing interest. The polymer coating of drug-loaded particles is one of the most common methods used for controlling drug delivery. Such multilayered particles could be either filled into capsules or compressed into tablets for their oral administration. However, many studies have noticed that coating films are damaged during the compression process, leading to significant changes in drug release profiles. The aims of this study were to investigate the effects of a thin cushioning layer [made of HydroxyPropylMethyl Cellulose (HPMC)] applied on coated theophylline particles upon particle characteristics, tablet pr…
Preformulation: Effect of Moisture Content on Microcrystalline Cellulose (Avicel PH-302) and Its Consequences on Packing Performances
1999
This study evaluates the influence of moisture content on the packing performances of a new grade of microcrystalline cellulose (MCC) (Avicel PH-302) either by classical method or by an unconventional compression technique (constant volume reduction of powder bed). An increase in moisture content decreases the apparent density of the powder bed, resulting from interparticulate friction enhancement. This modification of apparent density seems to be the main effect caused by the presence of humidity, which explains the variations of compression properties, like an increase of powder plasticity generally observed in the experimental conditions.
Detection of Irradiated Food and Evaluation of the Given Dose by Electron Spin Resonance, Thermoluminescence, and Gas Chromatographic/Mass Spectromet…
2018
Abstract The treatment of food with ionizing radiation, at doses lower than 10 kGy, is a preservation technology, which can be used to reduce food spoilage due to microorganisms and to decrease insect infestation, enhancing, in the same time, the hygienic quality, extending the shelf life of food itself. In order to increase the general consumer acceptance and accordingly to facilitate the commercialization and trade of irradiated food, the European Committee for Standardization (CEN) validated reliable analytical techniques to identify irradiated foodstuffs for legal control purposes, distinguished in Chemical, Physical, and Microbiological ones, depending on the characteristics of marker …