A magnetic target drug delivery system consisting of biodegradable polymeric microspheres (poly D, L-lactic acid) loaded with magnetite nanoparticles (10-100 nm) and anticancer drug (paclitaxel) was studied. The magnetite nanoparticles were synthesized by chemical precipitation. The as-synthesized magnetite nanoparticles were subsequently introduced into a mixture of polymer magnetic polymeric composite particles were investigated and further correlated with the reaction parameters. It was found that the size and characteristics of the polymeric composite particles depended on the viscosity of the polymer solution. Preliminary drug release experiments showed that the loaded drug was released with the degradation of the polymer. The release rates could be enhanced by an oscillating external magnetic field. / Singapore-MIT Alliance (SMA)

Thesis (M.Ch.E.)--University of Delaware, 2006. / Principal faculty advisor: Annette D.Shine, Dept. of Chemical Engineering. Includes bibliographical references.

Studies that involve natural fiber orientation in a matrix were mostly based on regulating shear forces during mixing of fiber and matrix. This study attempts to propose a novel technique for orientating natural fibers like cellulose in a viscous polymer matrix such as polylactic acid (PLA) by applying the concepts of magnetism. Orientation of cellulose fibers in a PLA was achieved by modifying the cellulose fibers with a ferromagnetic entity and subjecting to a magnetic field. Chemically modified cellulose fibers (CLF) were oriented in dilute polylactic acid by subjecting the fiber and matrix to a magnetic field of ≈ 4T (Tesla). CLF and Microcrystalline cellulose (MCC) were oxidized with Hydrogen peroxide and further reacted with activated Ferrous sulphate heptahydrate (FeSO4.7H2O) in order to form Cellulose-Fe complexes. Chemically modified CLF was characterized by spectroscopic, thermal and morphological methods. The results from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR spectroscopy) agree that coordination bonds were formed between deprotonated and/or oxidized hydroxyl groups of cellulose and Fe2+ ions. Powder X-ray diffraction (PXRD) was used to compare the crystallinity of unmodified and modified samples of CLF. Thermal properties of modified cellulose were studied using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). Scanning electron microscopy (SEM) results showed that there was minimal morphological change occurred to cellulose after treatment. It was also observed that the electrical conductivity of cellulose modified with Fe 2+ was higher than that of unmodified samples. The modified CLF was then mixed with polylactic acid diluted with dichloromethane and the fibers in the matrix suspension were subjected to a magnetic field of ≈ 4T. The suspension was allowed to solvent cast inside a glass vial in the magnetic field. Morphological examination of the fiber matrix composites using confocal microscopy showed that CLF were successfully oriented along the flux direction of the magnetic field.

Studies that involve natural fiber orientation in a matrix were mostly based on regulating shear forces during mixing of fiber and matrix. This study attempts to propose a novel technique for orientating natural fibers like cellulose in a viscous polymer matrix such as polylactic acid (PLA) by applying the concepts of magnetism. Orientation of cellulose fibers in a PLA was achieved by modifying the cellulose fibers with a ferromagnetic entity and subjecting to a magnetic field. Chemically modified cellulose fibers (CLF) were oriented in dilute polylactic acid by subjecting the fiber and matrix to a magnetic field of ≈ 4T (Tesla). CLF and Microcrystalline cellulose (MCC) were oxidized with Hydrogen peroxide and further reacted with activated Ferrous sulphate heptahydrate (FeSO4.7H2O) in order to form Cellulose-Fe complexes. Chemically modified CLF was characterized by spectroscopic, thermal and morphological methods. The results from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR spectroscopy) agree that coordination bonds were formed between deprotonated and/or oxidized hydroxyl groups of cellulose and Fe2+ ions. Powder X-ray diffraction (PXRD) was used to compare the crystallinity of unmodified and modified samples of CLF. Thermal properties of modified cellulose were studied using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). Scanning electron microscopy (SEM) results showed that there was minimal morphological change occurred to cellulose after treatment. It was also observed that the electrical conductivity of cellulose modified with Fe 2+ was higher than that of unmodified samples. The modified CLF was then mixed with polylactic acid diluted with dichloromethane and the fibers in the matrix suspension were subjected to a magnetic field of ≈ 4T. The suspension was allowed to solvent cast inside a glass vial in the magnetic field. Morphological examination of the fiber matrix composites using confocal microscopy showed that CLF were successfully oriented along the flux direction of the magnetic field.

Biologiškai skaidžių atliekų kompostavimui didelę įtaką turi anglies ir azoto santykis, priklausantis nuo kompostuojamų medžiagų rūšies. Kokybiškam kompostui pagaminti būtinos trys pagrindinės fazės: temperatūros kilimo, aukštos temperatūros ir temperatūros kritimo. Oro temperatūra buvo palanki kompostavimo procesui – vidutinė mėnesio temperatūra buvo aukštesnė arba artima daugemiačiams vidurkiams, o kritulių kiekis kompostavimo metu buvo permainingas. Komposto temperatūra priklausė nuo kompostavimo procesui būdingos fazės ir matavimo vietos – aukščiausia temperatūra (nuo 63 iki 82oC) nustatyta termofilinio proceso metu aukščiausios komposto vietos giliuosiuose sluoksniuose. Rūgštingumas komposto krūvoje kito nuo neutralaus (pH 7) kompostavimo pradžioje, termofilinės kompostavimo fazės metu tapo šarminės reakcijos (pH 8,0–8,3), temperatūros kritimo fazėje komposto rūgštingumas mažėjo iki neutralių reikšmių (pH 7,0–7,1). Optimalus kompostavimui drėgnumas (50–60%) buvo pasiektas trečią kompostavimo savaitę. Kompostavimo aikštelėse gaminant kompostą po atviru dangumi būtina atsižvelgti į meteorologines sąlygas, kurias vertinant galima parinkti tinkamą komposto krūvos vartymo dažnumą bei dirbtinio laistymo poreikį. / The carbon to nitrogen ratio, depending on the type of compostable materials, has a great impact on the composting of biodegradable waste. The three main phases necessary for obtaining the high-quality compost: temperature rise, high temperature and temperature drop. The air temperature was favourable to the composting process – the average monthly temperature was above or close to the multi-annual average, and the rainfall has been erratic during composting. The compost temperature depended on the phase and the measurement location characterized by the composting process – the highest temperature (from 63 to 82 °C) was determined during the thermophilic process in the deep layers of the highest composting place. The acidity of the compost pile varied from neutral (pH 7) at the beginning of composting, became alkaline (pH 8,0–8,3) during the thermophilic composting phase, the compost acidity decreased to neutral values (pH 7,0–7,1) during the temperature drop phase. The optimum composting humidity (50–60%) was achieved on the third week of composting. When the compost is produced in the open air composting sites, it is necessary to take account of the meteorological conditions. According to these evaluated conditions, the proper moving procedure frequency and the need for artificial irrigation can be selected for the compost pile.

Pharmaceuticals in the aquatic environment is an emerging issue and the risks they pose are mostly unknown. They are used in large amounts throughout the world and can enter the environment, as the active metabolite or unmetabolised, through excretion by people and improper disposal. As these drugs are designed to have specific biological effects in a specific organism (as well as sometimes having other non-specific side effects), their potential to cause effects within the environment is great. Clofibric acid (the major metabolite of the lipid lowering drug, Clofibrate) is non-biodegradable, highly motile, very persistent and frequently detected at μg/I levels in the environment. I studied possible effects of clofibric acid in fish, using different experimental approaches and endpoints. The studies involve two different species, and for one of these species, fish at different stages of development. The chapters within this thesis have presented the first evidence (albeit preliminary) of clofibric acid having effects on both adult and embryo fish. When fathead minnow embryos were exposed to clofibric acid, the effects seen included changes in the eggshell, time to hatch, hatchability, mortality and viability. Adult fathead minnow were similarly exposed and significant effects on specific parameters were also observed. These included effects on lipid metabolism, steroidogenesis and spermatogenesis - thought to be via cholesterol transport - as well as significant effects on the expression of several genes involved in lipid metabolism and detoxification. Exposure of juvenile (sexually undifferentiated) bream also found significant differences in some endpoints. Other results suggested, less pronounced effects of clofibric acid on some other parameters. The results from this research show that there are effects of clofibric acid in pathways which were not only unexpected in fish (for example, steroidogenesis, spermatogenesis and gene expression), but also at concentrations below those previously shown to have any biological effects on fish. These effects indicate that clofibric acid may potentially have an impact on fish fecundity, and even more worryingly, on human health for those people prescribed it.

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed Feb. 5, 2008; title from title screen. Includes bibliographical references (p. 65-68).

Thesis (M.Sc.(Chemical Engineering))--University of Pretoria, 2007. / Abstract in English. Includes bibliographical references (leaves 74-80).

La recherche sur les matériaux diélectriques souples et biodégradable a été augmenté considérablement en raison de l'augmentation des exigences concernant l'énergie et les questions environnementales. Les composites polymériques, avec constante diélectrique élevée ont ainsi, été préférés par rapport aux composites à base de céramique pour les périphériques de stockage de l'énergie. L'objectif de cette thèse est de fabriquer une électrode biodégradable matériaux à base de nano-fibrilles de cellulose natives et oxydés (CNF) et de graphène pour améliorer le stockage diélectrique ainsi que les applications de stockage de charge électrochimique. La présente méthode de réduction, induite par les UV sur l'oxyde de graphène (GO) dans des matrices de cellulose, est une alternative prometteuse aux traitements à base de solvant en évitant la détérioration des propriétés des matériaux et l'utilisation de solvants organiques. Cette méthode pourrait être étendue à d’autres matériaux composites polymères. / The research on biodegradable and flexible dielectric materials has been increased widely because of increasing requirements about energy and environmental issues. Polymeric composites with high dielectric constant have, thus, been demanded increasingly compared to ceramic based composites for energy storage devices. The objective of this thesis is to fabricate a biodegradable electrode materials based on pristine and oxidized cellulose nanofibrils (CNF) with different graphene based fillers for enhanced dielectric storage as well as electrochemical charge storage applications. The presented dry method of UV induced reduction of graphene oxide (GO) in cellulose matrices are promising alternatives to solvent based treatments avoiding the deterioration of material properties and the use of organic solvents. This method could be extended to alternative polymer composite materials. In contrast to previous reports, the dielectric properties mainly focussed on the higher frequency regions to provide real, intrinsic material properties and obtained significant enhancement than reported studies. This approach gives a new insight to the exact performance of materials on dielectric charge storage applications. The current study gives more insight for the development of flexible, lightweight and biodegradable electrode materials for energy storage device applications.

Charles University Faculty of Pharmacy in Hradci Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Petra Staňková Title of Thesis: Pharmaceutical applications of polyesters as drug nanocarriers Nanoparticles are nowadays intensively studied and perspective type of a drug carrier. Its potential is based on a possibility of targeted drug delivery and controlled drug release. The theoretical part is about nanoparticles types, polymers derived from α-hydroxyacids (PLA, PGA, PLGA). Focus is given on methods of nanoparticles preparation: dispersion of preformed polymers or the polymerization of monomers. The modification of particles surface and practical use of nanomedicine in healthcare are described in other chapters. The research in experimental part is focused on the influence of different types of PLGA and their weighing on the size, polydispersity, nanoparticles zeta potential and encapsulation efficiency of rhodamine B. Nanoparticles were prepared by nanoprecipitation method or by solvent evaporation method. The Zetasiser ZS 90 device was used to measure the size of the nanoparticles and to measure zeta potential. The result of the research shows the most suitable weighing for creation of nanoparticles is 25 mg. The samples of this weighing show a...