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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Využití core-shell kolon pro stanovení flukonazolu / Using of core-shell columns for fluconazole determination

Brokešová, Kateřina January 2014 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biophysics and Physical Chemistry Candidate: Kateřina Brokešová Supervisor: Ing. Martin Drastík, Ph. D. Thesis title: The use of core-shell columns for fluconazole determination A novel HPLC method for determination of fluconazole in dissolution test samples was developed and partly validated. A matrix formed by lactic and glycolic acid copolymer branched by different compounds was used as a drug carrier. Fluconazol was incorporated as the model drug. The concentration profile of fluconazole was studied by developed HPLC method during the dissolution test. A modern core-shell column Ascentis Express RP-Amide, 10 cm × 3.0 mm; 2.7 μm was employed. A mixture of acetate buffer pH 5.0:methanol (80:20) served as the mobile phase. The flow rate was 0.70 ml/min and the detection wavelength was 260 nm. The temperature of analysis was 50 řC. The retention time of fluconazole was 3.3 min and the whole analysis took just 4 min. Keywords: fluconazole, core-shell column, HPLC, PLGA
112

Granulometrie nanočástic z kopolymerů alifatických hydroxykyselin. / Granulometry of nanoparticles from aliphatic acids copolymers.

Šrejma, Robert January 2016 (has links)
The diploma thesis is focused on the study of influence on the composition of the system to the size of the nanoparticles from aliphatic polyesters with linear and branched molecules constitution. The emulsion method for distributing of solvent was chosen for preparation of nanoparticles. The theoretical part describes the nanoparticles, its origin and application. The following part is applying to biodegradable polymers, especially PLGA. There is also a mention of antifungal agent terbinafine. The nanoparticles are prepared of this substance. The process is described in the experimental part of thesis. The experimental part is testing different composition of samples. A main emphasis is on the choice of polymer solvent and emulsifier. There are also applied mixtures of solvents and emulsifiers. The important aspect is the evaluation of incorporated terbinafine, which has been the model drug. Prepared dispersions were exposed to stress conditions in the form of several days-storage and centrifugation.
113

Zjednodušení HPLC analýzy terbinafinu ve vzorcích na bázi biodegradabilních polyesterů / Simplification of terbinafine HPLC analysis of samples based on biodegradable polyesters

Malovaná, Andrea January 2016 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biophysics and Physical Chemistry Candidate: Andrea Malovaná Supervisor: Ing. Martin Drastík, Ph. D. Diploma thesis: Simplification of terbinafine HPLC analysis of samples based on biodegradable polyesters A HPLC method for determination of terbinafine in samples consisting of copolymers of lactic and glycolic acid was optimized and validated. The development of the method was based on the finding of suitable chromatographic conditions for separation of terbinafine. The separation was performed on the Ascentis Express ES-CN, 15 cm × 4.6 mm; 2.7 μm core- shell column. The mixture of the citrate phosphate buffer pH 4 and acetonitrile in ratio 40:60 (v/v) was chosen as the mobile phase. The mobile phase flow rate was set to 1.4 ml/min and the temperature to 30 řC. The injection volume of samples containing terbinafine was 5 µl. The UV detection at 226 nm was employed. The retention time of terbinafine was 3.3 min. The whole analysis was completed within 4 min. The method was validated, following parameters were tested: column efficiency, factor of symmetry, LOD, LOQ, linearity, repeatability and robustness. Keywords: terbinafine, HPLC, core-shell column, PLGA
114

Vliv formulačních faktorů na velikost polyesterových nanočástic. / Influence of formulation factors on the polyester nanoparticles size.

Športeň, Radek January 2016 (has links)
In the theoretical part of this thesis are described various types of nanoparticles, such as polymeric particles, liposomes, micelles and solid lipid nanoparticles. There are presented basic informations concerning methods of particles preparation in the laboratory conditions such as solutions of polymers dispersion methods by intensively stirring, coacervation of the solutions of polymers, polymeration methods in dispersions, and the exploitation of methods of dispersion of polymeric solutions in the supercritical solvents. In the folowing part of this thesis are some concise informations about the methods of evaluation of basic parameters of the nanoparticulate systems. There are summarised the trivial informations concerning granulometry of particles, their zeta potential, encapsulation effectivity of drugs, and also about the particles shape factor. The focus of this thesis is in the experiment, the main deal were in minimisation of the particle size prepared by the method of emulsification of biodegradable aliphatic α-hydroxyacids polyesters solutions. The main process arrangement was the selection of the appropriate solvent of polymers in the inner emulsion phase and the founding for the mostly efficient emulsifier during the dispersion process of polymer solutions. In process of the...
115

Částice s protimikrobním stříbrem. / Particles with antimicrobial silver.

Svobodová, Dana January 2016 (has links)
Charles Univerzity in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Candidate: Dana Svobodová Supervisor: doc. RNDr. Milan Dittrich, CSc. Diploma thesis title: Particles with antimicrobial silver The theoretical part of this diploma thesis outlines a brief overview of recent findings on silver nanoparticles. Further, it concerns the kinetic properties of colloidal systems, methods of evaluating the size and shape of colloidal particles, mechanism of antimicrobial activity of colloidal silver and methods of preparation of nanoparticles. Concise information about the toxicity of silver nanoparticles and their impact on the environment is also included. In the experimental part comprehensive report on the results of measurements of granulometric characteristics of microparticles and nanoparticles by photon correlation spectroscopy (PCS) is included. The influence of various modifications of preparation procedures and processing on stability, size and the polydispersity of the size in terms of the volume and intensity diameter of the particles with elemental silver deposited on the surface was studied. Optimisation of the disperse system, quality control of the content of colloidal particles by subsequent reduction, the possibilities of using centrifuge and...
116

Využití core-shell kolon pro stanovení mikonazolu / Using of core-shell columns for miconazole determination

Hloušková, Martina January 2015 (has links)
BSc. Martina Hloušková Supervisor: Ing. Martin Drastík, Ph.D. The aim of this diploma thesis was the optimization and validation of a HPLC method for miconazole determination in samples supplied by the Department of Pharmaceutical Technology. A gradual miconazole release dependent on the composition of the copolymere of glycolic and lactic acid was studied. HPLC analysis was performed using a modern core-shell Column Ascentis Express RP- Amide, 10 cm x 3.0 mm; 2.7 μm. Optimized analytical conditions were: mobile phase methanol:water 70:30, flow rate 0.8 ml/min, temperature 45 řC, injection 5 l and UV detection at 220 nm. Miconazole retention time was 5.65 min. The entire analysis was carried out in 7 minutes. When the optimal conditions of analysis were determined, the method could be validated. The following parameters were monitored during validation: linearity, selectivity, efficiency, LOD, LOQ, repeatability and tailing factor. All of the monitored parameters met the requirements of the Czech Pharmacopoeia.
117

Modified soy protein based adhesives and their physicochemical properties

Qi, Guangyan January 1900 (has links)
Doctor of Philosophy / Department of Grain Science and Industry / Xiuzhi Susan Sun / Soy protein is one of the most promising bio-degradable adhesives, with great potential as alternatives synthetic petroleum based adhesives for wood composite industries. However, its intrinsic drawbacks such as low water resistance, high viscosity, and short shelf life still limit its broad application. In this research, soy protein was further modified and characterized to improve adhesion properties, flow-ability, water resistance, and long shelf life, which could facilitate the industrialization of soy protein based adhesives. In this study, we exploited the in situ sodium bisulfite (NaHSO3) modification on soy protein in soy flour-water extracts, and then the modified soy protein was obtained through acid precipitation. First, different concentrations of NaHSO3 were used to modify soy flour slurry, then glycinin-rich and β-conglycinin-rich fractions were precipitated at pH 5.4 (SP 5.4) and pH 4.5 (SP 4.5), respectively. Unmodified sample SP 5.4 and SP 4.5 showed clay-like properties and viscoelastic properties, respectively; whereas with addition of NaHSO3 in range of 2-8 g/L, both SP 5.4 and SP 4.5 had the viscous cohesive phase with good handability and flow-ability. The overall adhesion performance of SP 4.5 was better than SP 5.4; the wet strength of these two fractions was in the range of 2.5-3.2 MPa compared to 1.6 MPa of control soy protein isolate. Then soy protein with various β-conglycinin/glycinin (7S/11S) ratios were extracted from soy flour slurry and characterized for adhesion properties based on the different solubility of 7S and 11S globulins. Seven glycinin-rich soy protein fractions and six β- conglycinin-rich soy protein fractions were obtained. According to the morphology, viscosity, and particle size results, we proposed that proper protein-protein interaction, hydration capacity (glycinin-rich fractions), and certain 7S/11S ratios (β-conglycinin-rich fractions) in modified soy protein are crucial to continuous protein phase formation. The viscous cohesive samples were stable for up to several months without phase separation at room temperature, with the wet adhesion strength of 2.0-2.8 MPa. The soy protein modified with NaHSO3 showed good compatibility with commercial glues applied on plywood and paper labeling fields. The modified soy protein made some functional groups, carboxylic (-COOH), hydroxyl (-OH) and amino groups (-NH2) available, which cross-linked with hydroxymethyl groups (-CH2-OH) from urea formaldehyde (UF) wood glue. The modified soy protein (MSP) with pH 4.8 also acted as an acidic catalyst for the self-polymerization of UF based resin. The wet adhesion strength of MSP/UF blends (40/60) was 6.4 MPa with 100% wood cohesive failure, as compared to 4.66 MPa of UF. As to the paper labeling application, peel strength of MSP on glass substrate increased rapidly, with curing time much shorter than commercial polyvinyl acetate based adhesives (PVAc). And the MSP/ PVAc blends showed shorter curing time, higher water resistance and lower viscosity than pure PVAc. Chemical modification could also enhance the adhesion strength of MSP. 2-octen-1- ylsuccinic anhydride (OSA) was proved to be grafted on soy protein through reaction between amine, hydroxyl groups of protein and anhydride groups. The oily nature and hydrophobic long alkyl chains of OSA mainly contributed to the significant water resistance improvement of MSP.
118

Granulometrická charakterizace nanočástic metodou PCS. / Granulometric characterisation of nanoparticles by the PCS method.

Jaworski, Jakub January 2019 (has links)
In the theoretical section of presented diploma thesis are discussed various nanoparticles such as micelles and liposomes, solid lipid nanoparticles and polymeric nanoparticles. Special attention was focused on copolymer PLGA. There are characterized different procedures in the preparation of nanoparticles. From the approches for nanoparticles evaluation are chosen measuring size of nanoparticles and their zeta potential. The experiment was almost unambiguously focused on study of effect of diffrent factors on nanopartlicles size and distribution from linear PLGA and PLGA used for branching of tripentaerythritol and polyacrylic acid. Keywords: nanoparticles, size, size distribution, zeta potential, interactions of nanoparticles
119

INVESTIGATION OF BIODEGRADABLE IRON-MANGANESE ALLOYS WITH VARIOUS POROSITY

Sabrina M Huang (6843719) 05 August 2019 (has links)
<p>Bioresorbable iron-manganese (Fe-Mn) alloys are considered as a new class of biomaterials for the development of orthopedic fixation devices due to their promising mechanical properties, comparable to the human cortical bone, and the ability to degrade in the physiological environment and release small quantities of metallic ions/particles that are absorbable by the host. The greatest challenge for developing an ideal resorbable Fe-Mn alloy is to increase the degradation rate of the alloy without compromising the alloy biocompatibility, that is, causing zero or minimal local and systemic toxicity to the tissue. Another challenge is to improve osteo-integration through inducing a cascade of events leading to tissue ingrowth.</p> <p> </p> <p>The incorporation of porosity into the Fe-Mn alloys aimed to increase the corrosion rate and to provide the three-dimensional structure for cellular activity and nutrient transport. The Fe-30wt.%Mn alloys with 0-, 5-, 10-, and 60-volume percent porosity were produced through the space holder technique in powder metallurgy. The space-holder material, ammonium bicarbonate (NH<sub>4</sub>HCO<sub>3</sub>), was sieved to a particle size ranging 355~500 µm. The microstructures and mechanical properties of the alloys, as well as the influence of the degree of porosity on the alloy corrosion rates comparing to the concentrations of the degraded metal ions were investigated. Although the Fe-30Mn alloys containing 60-vol% porosity exhibited the lowest average ultimate compressive strength of 381 MPa among the tested groups, they were still mechanically stronger than a typical human wet compact bone. Furthermore, the alloys had the highest average corrosion rate of 0.98 ± 0.20 mm/year, compared to 0.13 ± 0.07 mm/year for the non-porous Fe-30Mn alloys. Nevertheless, the extract from the 60%-pore group had a cytotoxicity effect to the bone marrow stem cells (BMSCs) at an average normalized cell viability of 58%, which was below the standard viability of 70%, considered as cytotoxic in the indirect cytotoxicity study. The cytotoxicity study also corresponded to the highest level of transition metal ions Mn<sup>2+</sup> released into the media for the 60%-pore group at an average ion released rate of 7 mg/day, compared to the other groups presenting similar Mn<sup>2+</sup> released rates about 4 mg/day after 1 day of incubation. The extreme case of the 60%-pore group demonstrated the tradeoff between the corrosion rates and biocompatibility. On the other hand, the 10%-pore group showed an average ultimate compressive strength of 737 MPa comparable to the stainless steel 316L, an average corrosion rate of 0.260 ± 0.09 mm/year, which was 2-fold higher than the non-porous group, and an average cell viability of 86% close to the non-porous group. It is promising based on the above results, however, the osteo-integration of the 10%-pore group in terms of cell-to-cell and alloy-to-cell interactions was not ideal. </p>
120

Desenvolvimento de novos filmes comestíveis de gelatina contendo nanoemulsão de óleo essencial de pimenta preta ou manjerona reforçados com cloisite Na+ /

Saranti, Tascila Ferreira da Silva January 2019 (has links)
Orientador: Márcia Regina de Moura Aouada / Resumo: A crescente preocupação em se consumir produtos que sejam ecologicamente corretos tem motivado pesquisas no desenvolvimento de novos materiais. Nesse sentido, filmes à base de polímeros naturais têm sido desenvolvidos com o objetivo de substituir parcialmente a utilização dos polímeros tradicionais. A utilização desses filmes, além de diminuir a geração de resíduos plásticos descartados no meio ambiente, podem ainda exercer a função de embalagem ativa, estendendo a vida útil dos alimentos. O presente trabalho consiste na elaboração de novos filmes comestíveis à base de gelatina e nanoemulsão de óleos essenciais de manjerona e de pimenta-preta. A gelatina é um polímero natural, biocompatível e biodegradável, possuindo boa capacidade de formar filmes flexíveis. Os óleos essenciais de manjerona e de pimenta-preta possuem boa aceitação por parte dos consumidores, além de excelentes propriedades antioxidantes e antimicrobianas. Quando adicionados às matrizes poliméricas em forma de nanoemulsão, pode contribuir para a diminuição da permeabilidade a vapores de água e aumentar a tenacidade dos filmes. Visando a melhoria da resistência mecânica dos filmes, dispersão de argilas vem sido incorporadas as dispersões filmogênicas. Nesse trabalho, foi utilizada a cloisite Na+. Os filmes produzidos foram caracterizados quanto à análise subjetiva, permeabilidade ao vapor de água, propriedade mecânicas, propriedades térmicas, difração de raios-x, ângulo de contato e microestruturais. As nanoem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The growing concern to consume products that are ecologically correct has motivated the study in the development of new materials. In this sense, films based in natural polymers have been created with the aim of replacement of the traditional polymers. The use of these films behind to decreasing the generation of plastic waste in the environment, it can still be active packaging, extending the food shelf-life. This present study consists in the elaboration of a film based in gelatin and marjoram and black pepper essential oils nanoemulsions. Gelatin is a natural, biocompatible and biodegradable polymer, it has good flexible and film forming ability. The marjoram and black pepper essential oil has a good acceptance by the consumers, as well as excellent antioxidant and antimicrobial properties. When incorporated to polymer matrices by the nanoemulsions way, they can contributed to the reduction of water vapor permeability and increase film tenacity. By the aim of improve the mechanical proprieties, clay dispersions had been incorporated in the film dispersions. In this study Na+ cloisite was used. The produced films were characterized by the subjective analysis, water vapor permeability, mechanical properties, thermal properties, x-ray diffusion, contact angle and microstructural. The nanoemulsions characterized by the particle size, presented results between 250 and 181nm to black pepper, and 82 and 47nm to marjoram essential oil. Related to the water vapor permeability and t... (Complete abstract click electronic access below) / Mestre

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