To see the other types of publications on this topic, follow the link: Physicochemical characterizations.
Dissertations / Theses on the topic 'Physicochemical characterizations'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Physicochemical characterizations.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Roger, Maxime. "Développement de systèmes π-conjugués aux propriétés de fluorescence induite par l'agrégation (AIE)." Thesis, Université de Montpellier (2022-….), 2022. http://www.theses.fr/2022UMONS005.
Full textAbstract:
Le phénomène de fluorescence, bien qu’assez rare à l’état naturel, est couramment exploité dans le domaine de l’optoélectronique pour la fabrication d’OLEDs ou de concentrateurs solaires, mais aussi dans le domaine biomédical pour l’imagerie ou la thérapie. Ce travail est axé sur la conception de molécules fluorescentes présentant une émission induite par l’agrégation (AIE, « Aggregation Induced Emission »). Contrairement aux fluorophores conventionnels pour lesquels l’émission est éteinte à l’état agrégé, les fluorophores AIE possèdent un comportement inverse : ils sont peu fluorescents en solution mais le deviennent à l’état solide. Ce phénomène résulte de la restriction des mouvements intramoléculaires dans un environnement contraint (RIM, « restriction of intramolecular motion ») permettant de favoriser les voies de désexcitation radiatives. Ce manuscrit s’inscrit dans ce contexte et est divisé en quatre chapitres. Le premier décrit le concept et les conditions requises permettant à une molécule d’être dotée de la propriété AIE. Les trois suivants abordent tout d’abord la synthèse et l’étude de fluorophores AIE de la famille des diphénylebuta-1,3-diènes portant des groupements dérivés du thiophène électropolymérisables. Le chapitre suivant aborde la synthèse de systèmes donneurs-accepteurs basés sur le motif tétraphényléthène (TPE) en vue d’obtenir des propriétés d’absorption et/ou émission dans le domaine des grandes longueurs d’onde du rouge et du proche infrarouge (600 nm-1200 nm). Enfin, le dernier chapitre, s’intéresse au contrôle et à la modulation de la longueur d’onde d’émission en exploitant le comportement AIE de deux fluorophore à base de TPE et de quinoline malononitrile induit par la transition de phase soluble/insoluble d’un polymère thermosensible, la poly(2-n-propyl-2-oxazoline).Mot clés : Design moléculaire, fluorophore, fluorescence, émission induite par l’agrégation, AIE, synthèse organique, diphénylbuta-1,3-diène, tétraphényléthène, quinoline malononitrile, poly(2- oxazoline)The fluorescence phenomenon while relatively rare in nature, is also commonly operating in various fields including optoelectronics for the conception of OLEDs and solar concentrators and biomedicals for imaging and therapy. This work falls into this context and aims at designing fluorescent molecules possessing aggregation induced emission (AIE) properites. In contrast to conventional fluorophores that suffer of aggregation caused quenching (ACQ) phenomenom, AIE fluorophores exhibit in general strong emission in the solid state while there are non-emissive in solution due to the restriction of intramolecular motion (RIM) which favor the radiative decay. This manuscript is built upon four chapters. The introduction describes the concept and the conditions required for a molecule to exhibit a AIE behaviour. The second chapter describes the synthesis and the characterization of AIEbased diphenylbuta-1,3-diene skeleton bearing electropolymerizable thiophene moieties. The third chapter is related to the development of donor-acceptor systems built upon a tetraphenylethene (TPE) core in view of extending their absorption / emission properties to the red or near infrared (600 nm - 1200 nm) region of the spectrum. Finally, the last chapter deals with the control and the modulation of the emission wavelength by exploiting the AIE behavior of two fluorophores based on tetraphenylethene and quinoline malononitrile induced by the folding of the chain of a thermoresponsive polymer, the poly(2-n-propyl-2-oxazoline).Keywords: Molecular design, fluorophore, fluorescent, aggregation induced emission, AIE, organic synthesis, diphénylbuta-1,3-diène, tetraphenylethene, quinoline malononitrile, poly(2-oxazoline)
2
De, Zordi Nicola. "Modified release of pharmaceutical dosage forms." Doctoral thesis, Università degli studi di Trieste, 2012. http://hdl.handle.net/10077/7733.
Full textAbstract:
2010/2011During these three years, the research was focused on the preparation of pharmaceutical solid oral dosage forms with the aim to improve the dissolution behaviors and bioavailability of poor soluble drugs, or preparing sustained release systems for water-soluble drugs. In order to improve the bioavailability of poor soluble drugs, we adopted two strategies: 1) the micronization of the drug to increase their surface area, 2) preparing solid dispersions (SDs) using hydrophilic carrier. As known in the SDs the drug is dispersed or solubilized in an inert excipient or matrix where the active ingredient could exist in finely crystalline or amorphous state. When the system is exposed to aqueous media, the carrier dissolved and the drug is released as a very fine colloidal particles. This greatly reduction in particles size and the following surface area increase, results in an improvement of the dissolution rate. In addition to bioavailability enhancement, SDs systems were also directed towards the development of extender-release dosage forms using lipophilic carriers. For both the formulative approaches, we investigated the application of microwave (MW) and supercritical fluids (SCF) as preparative methods. In particular, MW ware employed for the preparation of solid dispersion either for immediate or sustained release of drugs, while SCF were investigated for the micronization and preparation of solid with the aim to prepare immediate release systems. Moreover, were investigated the thermodynamic aspect involved in the drug processing developing mathematical approaches able to predict the best operative conditions. Beside the preparation of these systems the physicochemical characterization of the compounds were investigated in order to understand the influence of the above technologies on the solid state of the materials. The goal of these behaviors was investigated trough the dissolution profile. From the obtained results these two technologies can be considered innovative and promising way to design particles.
XXIV Ciclo
1983
3
Lansita, Janice A. (Janice Ann) 1975. "Physicochemical characterization of immortal strand DNA." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/18038.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2004.Includes bibliographical references.
Adult tissue differentiation involves the generation of distinct cell types from adult stem cells (ASCs). Current understanding of tissue differentiation mechanisms is based on studies of protein and RNAs that asymmetrically segregate between daughter cells during embryogenesis. Whether or not other types of biomolecules segregate asymmetrically has not been widely studied. In 1975, John Cairns proposed that ASCs preferentially segregate the oldest parental template DNA strands to themselves and pass on newly replicated DNA strands to their differentiating progeny in order to protect the stem cell from inheriting DNA replication mutations. This laboratory has shown non-random chromosome segregation in murine fetal fibroblasts that model asymmetric self-renewal like ASCs. In these cells, chromosomes that contain the oldest DNA strands co-segregate to the cycling daughter stem-like cells, while chromosomes with more recently replicated DNA segregate to the non-stem cell daughters. Previously, cytological methods were reported to elucidate non-random segregation in these cells. This dissertation research provides additional confirmation of the mechanism using physicochemical methods. Specifically, buoyant density-shift experiments in equilibrium CsCl density gradients were used to detect co-segregated "immortal DNA strands" based on incorporation of the thymidine base analogue bromodeoxyuridine. In addition, DNA from cells undergoing non-random mitotic chromosome segregation was analyzed for unique DNA base modifications and global structural modifications (by HPLC and melting temperature analyses). To date, these studies show no significant differences compared to control randomly segregated DNA. Components of the mitotic chromosome separation
(cont.) apparatus that might play a role in the co-segregation mechanism were also evaluated. Two homologous proteins, essential for proper chromosome segregation and cytokinesis, Aurora A kinase and Aurora B kinase, were highly reduced in expression in cells retaining immortal DNA strands and may indicate a role for them in the immortal strand mechanism. These studies independently confirm the immortal strand mechanism and provide methods for its detection in other cell lines. In addition, observed changes in chromosome segregation proteins that are potential candidates for involvement in the mechanism have revealed a new area of investigation in the laboratory. These findings are relevant to understanding normal tissue development, cancer, and aging.
y Janice A. Lansita.
Ph.D.
4
COSTANTINI, GABRIELE. "Preparation and physicochemical characterization of glycoconjugate vaccines." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/29779.
Full textAbstract:
The project of my PhD course has been focused on the characterization of glycoconjugate vaccines to develop a largely applicable methodology to identify their glycosylation sites.
The saccharide antigens are covalently attached to the carrier protein by a spacer or using specific functionalities available in both components. The general analytical strategy has involved a tryptic digestion and an enzymatic or acid hydrolysis of carbohydrate antigens in glycoconjugates. The resulting mixture of peptides and glycopeptides with well-defined mass increment has been analyzed by liquid chromatography interfaced with a mass spectrometer (LC-MS) technique to qualitatively understand which lysine residues have been involved in the glycosylation process. Several conjugate vaccines against Candida albicans, Group A Streptococcus (GAS), Group B Streptococcus (GBS) and Neisseria meningitidis group A (MenA) have been analyzed to estimate the distribution of glycosylated lysine residues. Among those, GBS resulted the less glycosylated in comparison to Candida and MenA ones. This aspect it is probably due to the different conjugation chemistries and GBS polysaccharide size. The second part of my PhD project has been the synthesis of two β(1,3)-glucans antigens, a trisaccharide and a hexasaccharide and their conjugation to CRM197. The hexasaccharide has also been linked on a multimeric structure PAMAM4 and then conjugated to CRM197. The last part of this work has been the conjugation to CRM197 of a modified MenB LPS, provided from Institute of Biological Science (IBS) laboratory (National Research Council - Ottawa Canada).
The target sites of the carrier protein (CRM197) and LPS have been activated by two different reactans, and the final glycoconjugate has been obtained by the reaction of these two.
The resulting conjugate has been characterized (saccharide and protein content, MALDI-TOF mass spectrometry and NMR) using an accurate analytical panel.
5
CATALANO, ENRICO. "Physicochemical and biological characterization of magnetic nanoparticles for biomedical applications." Doctoral thesis, Università del Piemonte Orientale, 2015. http://hdl.handle.net/11579/81662.
Full textAbstract:
The overall goal of this project was the biological characterization by in vivo and in vitro testing of magnetic nanoparticles that can be used for various applications. The aim of this work was to understand which of the synthesized magnetic nanoparticles could be more suitable to be used as a carrier or platform for various applications in different scientific fields. Two different kinds of magnetic nanoparticles were developed: naked iron-oxide nanoparticles and silica or silica-based coated nanoparticles (core shell-type nanoparticles). Magnetic nanoparticles were prepared using a coprecipitation method. The structure, phase composition, physicochemical and surface properties, magnetic susceptibility, and release in vitro of MNPs were characterized by transmission electron microscopy, x-ray diffraction, scanning electron microscopy-energy dispersive x-ray spectroscopy, and a vibrating sample magnetometer. In vivo toxicity, in vitro toxicity, ROS production and genotoxicity were investigated. Therapeutic effects were evaluated by cell viability assays and flow cytometry assays. The tools developed in this thesis spanned a range of physical-chemical, biological and magnetic aspects and incorporate innovations on a nanometric range of scales. MNP-based technologies appear to hold a significant potential for a myriad of biomedical applications and the toxic potential of MNPs cannot be overlooked. For this reason we carried out different physicochemical and biological characterization of MNPs to identify a safe dose and formulation of MNPs. Understanding the relationship between the physicochemical properties of MNP constructs and their behavior will induce full translational potential of these nanoparticles. The magnetic nanoparticles prepared in this study have good biocompatibility and are suitable for further application in tumor hyperthermia.
6
衛星輝 and Sing-fai Wai. "Physicochemical characterization of brain ganglioside-stimulated protein kinase." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31236212.
Full text
7
Nishizawa, Mayu. "Physicochemical Characterization of Physiological Aspects of Protein Structure." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263680.
Full textAbstract:
京都大学新制・課程博士
博士(工学)
甲第23219号
工博第4863号
京都大学大学院工学研究科分子工学専攻
(主査)教授 田中 庸裕, 教授 近藤 輝幸, 准教授 菅瀬 謙治, 教授 佐藤 啓文
学位規則第4条第1項該当
Doctor of Philosophy (Engineering)
Kyoto University
DGAM
8
Wai, Sing-fai. "Physicochemical characterization of brain ganglioside-stimulated protein kinase /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19739722.
Full text
9
Elzey, Sherrie Renee. "Applications and physicochemical characterization of nanomaterials in environmental, health, and safety studies." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/494.
Full textAbstract:
As commercially manufactured nanomaterials become more commonplace, they have the potential to enter ecological and biological environments sometime during their lifecycle of production, distribution, use or disposal. Despite rapid advances in the production and application of nanomaterials, little is known about how nanomaterials may interact with the environment or affect human health. This research investigates an environmental application of nanomaterials and characterizes the physicochemical properties of commonly manufactured nanomaterials in environmental health and safety studies.
Characterization of nanomaterials for applications and environmental health and safety studies is essential in order to understand how physicochemical properties correlate with chemical, ecological, or biological response or lack of response. Full characterization includes determining the bulk and surface properties of nanomaterials. Bulk characterization methods examine the shape, size, phase, electronic structure and crystallinity, and surface characterization methods include surface area, arrangement of surface atoms, surface electronic structure, surface composition and functionality.
This work investigates the selective catalytic reduction (SCR) of NO2 to N2 and O2 with ammonia on nanocrystalline NaY, Aldrich NaY and nanocrystalline CuY using in situ Fourier transform infrared (FTIR) spectroscopy. It was determined that the kinetics of SCR were 30% faster on nanocrystalline NaY compared to commercial NaY due to an increase in external surface area and external surface reactivity. Copper-cation exchanged nanocrystalline Y resulted in an additional increase in the rate of SCR as well as distinct NO2 and NH3 adsorption sites associated with the copper cation. These superior materials for reducing NOx could contribute to a cleaner environment.
This work consists of characterization of commonly manufactured or synthesized nanomaterials and studies of nanomaterials in specific environmental conditions. Bulk and surface characterization techniques were used to examine carbon nanotubes, titanium dioxide nanoparticles, bare silver nanoparticles and polymer-coated silver nanoparticles, and copper nanoparticles. Lithium titanate nanomaterial was collected from a manufacturing facility was also characterized to identify occupational health risks. Particle size distribution measurements and chemical composition data showed the lithium titanate nanomaterial forms larger micrometer agglomerates, while the nanoparticles present were due to incidental processes.
A unique approach was applied to study particle size during dissolution of nanoparticles in aqueous and acidic conditions. An electrospray coupled to a scanning mobility particle sizer (ES-SMPS) was used to determine the particle size distribution (PSD) of bare silver nanoparticles in nitric acid and copper nanoparticles in hydrochloric acid. The results show unique, size-dependent dissolution behavior for the nanoparticles relative to their micrometer sized counterparts.
This research shows size-dependent properties of nanomaterials can influence how they will be transported and transformed in specific environments, and the behavior of larger sized materials cannot be used to predict nanomaterial behavior. The type of nanomaterial and the media it enters are important factors for determining the fate of the nanomaterial. These studies will be important when considering measures for exposure control and environmental remediation of nanomaterials.
10
Jores, Katja. "Lipid nanodispersions as drug carrier systems a physicochemical characterization /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972528334.
Full text
11
Protozanova, Ekaterina. "Physicochemical characterization of multistranded DNA assemblies, DNA frayed wires." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq53831.pdf.
Full text
12
Yezbick, Gabrielle. "Physicochemical Characterization and Isoflavone Profiling of Sourdough Soy Bread." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1345313529.
Full text
13
Tsutsumi, Maiko. "Physicochemical Characterization of Histamine Dehydrogenase and Its Enzymatic Reaction." Kyoto University, 2010. http://hdl.handle.net/2433/120473.
Full textAbstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第15430号
農博第1815号
新制||農||980(附属図書館)
学位論文||H22||N4529(農学部図書室)
27908
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 加納 健司, 教授 間藤 徹, 教授 渡邊 隆司
学位規則第4条第1項該当
14
Thompson, Meghan L. "Physicochemical and Structural Analysis of Polymers as Putative Drugs." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/4061.
Full textAbstract:
Sulfated low molecular weight lignins (LMWLs) have shown good activity as anticoagulants by allosterically inhibiting thrombin, as well as promising agents for treating emphysema through inhibition of elastolysis, oxidation, and inflammation. Sulfated LMWLs are chemo-enzymatically synthesized from starting monomers caffeic, ferulic, and sinapic acid into sulfated dehydropolymers known as CDS, FDS, and SDS. To further the LMWLs’ development as drugs, their structural composition and physicochemical characteristics were defined in this work. The molecular weight distribution profile of the sulfated LMWLs from size exclusion chromatography performed on a high pressure liquid chromatography system (SEC-HPLC) changed from bimodal when no surfactant is used in the mobile phase of the HPLC to unimodal when surfactant is used in the mobile phase. This indicates that some large molecular weight species, likely an aggregate of smaller molecular weight chains, are disrupted when surfactant is present. The resulting estimates of molecular weight calculated when surfactant is used in the mobile phase resulted in peak average molecular weights of 5700 Da for CDS, 7400 Da for FDS, and 4300 Da for SDS. These molecular weights are 17-45% higher and can be considered more accurate than the previously reported molecular weights (CDS: 3320 Da, FDS: 4120 Da, SDS: 3550 Da) because they were measured directly whereas previous estimates were calculated from GPC-HPLC data of the unsulfated LMWL precursors. Elemental analysis and distribution coefficient measurements were also performed on the LMWL library, revealing information about the level of sulfation and hydrophobic character of the sulfated LMWLs.
15
Huang, Chih-Te. "Physicochemical Characterization of Portuguese Clay and Nanocomposite Preparation with Polylactide." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30832.
Full textAbstract:
A Portuguese clay (BRN) from the North East city of Bragança was collected and characterized in terms of health treatment and applied towards the preparation of nanocomposites with Polylactide (PLA). The silt-clay fraction of BRN is mainly composed of smectite with less illite, kaolinite and other minerals. The physicochemical properties are applicable for the topical applications and are mainly influenced by smectite. With the hazardous elements present, further bioavailability tests should be conducted. PLA nanocomposites with BRN and Wyoming montmorillonite SWy-2 (MMT) were respectively prepared through the solution casting method with ultrasonic stirring and using cetyltrimethylammonium bromide (CTAB) as the surfactant. The X-ray diffraction patterns show the exfoliated structures in most samples. Thermal gravimetric analysis reveals the increased thermal stability of the nanocomposites. The complexes were also characterized by nitrogen adsorption, infrared analysis and nuclear magnetic resonance for comparing the differences between BRN and MMT.
16
Diak, Osama Abdel Razzaq Ahmad Abu. "Physicochemical characterization of solid dispersions prepared using hot-melt extrusion technology." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516942.
Full text
17
BATTISTA, SARA. "Preparation and physicochemical characterization of novel mixed liposomes for medical applications." Doctoral thesis, Università degli Studi dell'Aquila, 2019. http://hdl.handle.net/11697/147859.
Full textAbstract:
Liposomes are very useful aggregates due to the possibility to modulate their properties for the application area of concern. In this thesis the use of liposomes i) as delivery systems for natural substances with biological properties but low solubility in water such as (+)-usnic acid (UA) and curcuminoids (CUR) and ii) as sensors for a tumor biomarker, thymidine phosphorylase (TP) was investigated. The aim of this work is to evaluate how and to what extent changes in the chemical structure of liposomes components can affect their physicochemical properties.
Liposomes as drug delivery systems
Structurally related formulations were prepared and characterized to be used as UA or CUR delivery systems. In the case of UA, aggregates containing synthetic structurally related L-prolinol derivatives alone (micelles) or mixed with cholesterol in the presence (liposomes) or in the absence (quatsomes) of a natural phospholipid were investigated exploiting different methodologies of preparation and of removal of the unentrapped solute. The results of this investigation point out that the crucial role in affecting the aggregates and the solute properties is played by the synergistic effect between the chain length and the headgroup charge, besides the fluidity of the bilayer and the polarity of the solute. In particular, the z-potential of liposomes containing zwitterionic N-oxide synthetic surfactants that bear long chains was positive and not neutral as expected demonstrating that some parameters are not always easily predictable only on the basis of lipids molecular structure but also their organization in the bilayer is important. On the other hand, the preparation technique and the purification protocol affect mostly the stability of the aggregates.
Analogue formulations containing L-prolinol derivatives were also prepared to investigate the correlation between the structure of the synthetic surfactant with the antibacterial activity of liposomal UA. The obtained results underline that a similar headgroup charge of the synthetic component is not enough to assure the same efficacy of the treatment.
In the case of CUR, liposomes containing different saturated or unsaturated commercial phospholipids with or without cholesterol were investigated. All the formulations showed the ability to increase CUR solubility in water and to highly reduce their degradation to an extent strictly related to lipid molecular structure.
Liposomes as sensors
5-Fluorouracil (5-FU) is a chemotherapeutic agent largely used for the treatment of many solid tumors but has a very narrow therapeutic window because the level of its three target enzymes can significantly vary among patients. The aim of this research was dosing the level of one of them (TP, chosen as model) with a simple colorimetric analysis using polydiacetilene liposomes. In fact, the polydiacetylene units present in the bilayer polymerize under UV light generating a very high conjugated skeleton that confers to the solution normally a blue colour. If an external stimulation (in this case the interaction of TP with 5-FU covalently linked to liposomes surface) occurs, the solution can turn to red to an extent proportional to the concentration of the target enzyme in solution. Different mixed polydiacetylene liposomes properly functionalized with 5-FU were prepared and tested. The obtained results demonstrate that the electrostatic interactions between the target enzyme and liposomes surface, the polarity of the headgroup region and the rigidity/lipid packing of the bilayer, besides the composition, are decisive for the response of the system. Also the steric hindrance of the polar headgroup, moving away the chains, can reduce or inhibit an extended polymerization. In fact, the self-organization of monomers influences the colour of the solution and precise angles and relative distances between chains must be respected to achieve the required conjugation of the polymer backbone.
18
Rusu, Marin Viorel. "Composite materials made of chitosan and nanosized apatite preparation and physicochemical characterization /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974306916.
Full text
19
Rusu, Viorel Marin. "Composite materials made of chitosan and nanosized apatite : preparation and physicochemical characterization." Phd thesis, Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2005/231/.
Full textAbstract:
Taking inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite were investigated. A new preparation approach based on a co-precipitation method has been developed. In its earlier stage of formation, the composite occurs as hydrogel as suspended in aqueous alkaline solution. In order to get solid composites various drying procedures including freeze-drying technique, air-drying at room temperature and at moderate temperatures, between 50oC and 100oC were used. Physicochemical studies showed that the composites exhibit different properties with respect to their structure and composition. IR and Raman spectroscopy probed the presence of both chitosan and hydroxyapatite in the composites. Hydroxyapatite as dispersed in the chitosan matrix was found to be in the nanosize range (15-50 nm) and occurs in a bimodal distribution with respect to its crystallite length. Two types of distribution domains of hydroxyapatite crystallites in the composite matrix such as cluster-like (200-400 nm) and scattered-like domains were identified by the transmission electron microscopy (TEM), X-ray diffraction (XRD) and by confocal scanning laser microscopy (CSLM) measurements. Relaxation NMR experiments on composite hydrogels showed the presence of two types of water sites in their gel networks, such as free and bound water. Mechanical tests showed that the mechanical properties of composites are one order of magnitude less than those of compact bone but comparable to those of porous bone. The enzymatic degradation rates of composites showed slow degradation processes. The yields of degradation were estimated to be less than 10% by loss of mass, after incubation with lysozyme, for a period of 50 days. Since the composite materials were found biocompatible by the in vivo tests, the simple mode of their fabrication and their properties recommend them as potential candidates for the non-load bearing bone substitute materials.Inspiriert von Natur, bei der Kompositmaterialien aus Polymermatrices und anorganischen Füllstoffen z.B. in Knochen, Krustentieren und Eierschalen vorzufinden sind, wurde die Herstellungsmöglichkeit von Kompositmaterial aus Chitosan und Hydroxyapatitdispersionen untersucht. Basierend auf einem Kopräzipitationsverfahren wurde eine neue Herstellungsmethode entwickelt, die als flexibler Zugang zu einem Spektrum von Komposittypen führt. In den frühen Phasen der Kompositbildung entsteht ein in der wässrigen alkalischen Lösung suspendiertes Hydrogel, das durch Filtration und Zentrifugation isoliert werden kann. IR und Ramanspektroskopie klären das Vorhandensein von Chitosan und Hydroxyapatit im Kompositmaterial. Hydroxyapatit ist als Nanopartikel der Größe von 15-50 nm in bimodaler Verteilung in der Chitosanmatrix dispersiert, und in durch Transmissionselektronenmikroskopie (TEM), X-Ray Diffraction (XRD) und Konfokaler Laserscanmikroskopie (CSLM) nachweisbaren 200-400 nm großen Clustern assembliert. NMR-Relaxationsmessungen an Hydrogelkompositmaterial decken die Existenz zweier Klassen vorkommenden Wassers im Netzwerk auf, gebundenes und freies Wasser. Mechanische Tests zeigen, dass die mechanische Festigkeit etwa eine Größenordnung unter der von massivem Knochen liegt, der Festigkeit von porösem Knochen aber gleichkommt. Enzymatische Abbauraten des Kompostimaterials sind als langsam einzuschätzen. Eine 50-tägige Einwirkzeit von Lysozym führte zu einem Abbau von 10 % der Kompositmasse. Die sich durch in vivo Tests herausstellende Biokompatibilität, die einfachen Herstellungsmöglichkeiten und die physikochemischen Eigenschaften empfehlen dieses Material als vielversprechenden Kandidaten für Knochenersatzmaterial in mäßig belasteten Bereichen.
20
Saban, Waheed. "Synthesis, characterization and physicochemical properties of platinum naboparticles on ordered mesoporous carbon." Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8474_1320738516.
Full textAbstract:
In this study SBA-15 mesoporous silica template was synthesized and used as a sacrificial template in the preparation of ordered mesoporous carbon material. A chemical vapour deposition (CVD) technique using LPG or alternatively sucrose, pyrolyzed upon a mesoporous Si matrix were used to produce nanostructured ordered mesoporous carbon (OMC) with graphitic character after removing the Si template. The sucrose method was found to be a suitable route for preparing OMC. The OMC was used as a conductive three dimensional porous support for depositing catalytic nanophase Pt metal. Deposition of Pt nanoparticles on OMC was accomplished using a CVD method with Pt(acac)2 as a precursor. The synthesized nano-composite materials were characterized by several techniques such as, HRTEM, HRSEM, EDS, XRD, BET, TGA, FT-IR and CV.
21
Brunetti, Emilio. "Development and physicochemical characterization of calix[6]arene based chemical recognition systems." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/240961.
Full textAbstract:
Synthetic molecular receptors find applications in the selective extraction, transport and detection of neutral or charged species and the study of these systems is an important facet of supramolecular chemistry. In this thesis, we focused our attention on a specific family of molecular receptors called calix[6]arenes. These receptors possess a hydrophobic cavity formed by 6 aromatic rings that can accommodate small organic molecules. They can furthermore be easily functionalized and give rise to for example ditopic receptors or sensing systems. We worked with two families of calix[6]arenes but also looked at the complexation properties of some related compounds: a homooxacalix[3]arene and a resorcin[4]arene derivatives. The first part of this thesis is devoted to the study of the complexation properties of a fluorescent calix[6]tris-pyrenylurea. The binding of anions, ion pairs, ion triads and phospholipids was monitored by 1H Nuclear Magnetic Resonance (NMR) and Emission Spectroscopy. Our results showed that the receptor exhibits a remarkable selectivity for the sulfate anion in DMSO for which a binding constant of the order of 103 M-1 was found. In chloroform the affinity for sulfate is of the order of 105 M-1 and the selective recognition of ammonium-TBASO4 triads was observed (TBA = tetra-n-butylammonium; ammonium = PrNH3+, HexNH3+ or DodNH3+). This work has been reported in the paper “Fluorescent Chemosensors for Anions and Contact Ion Pairs with a Cavity-Based Selectivity” Emilio Brunetti, Jean-François Picron, Karolina Flidrova, Gilles Bruylants, Kristin Bartik and Ivan Jabin J. Org. Chem. 2014, 79, 6179–6188. We also showed that calix[6]tris-pyrenylurea displays a remarkable selectivity in chloroform for phospholipids bearing a phosphatidylcholine head (PCs) over those bearing a phosphoethanolamine head (PEs). We were able to show that this fluorescent receptor is able to extract PCs from a water solution enabling their quantification. This work has been reported in the paper “A Selective Calix[6]arene-based Fluorescent Chemosensor for Phosphatidylcholine Type Lipids” Emilio Brunetti, Steven Moerkerke, Johan Wouters, Kristin Bartik and Ivan Jabin Org. Biomol. Chem. 2016. Accepted Manuscript. DOI: 10.1039/C6OB01880G.The second part of this thesis is devoted to the evaluation of the binding properties of different receptors incorporated into dodecylphosphocholine (DPC) micelles. This strategy was used to make the hydrophobic molecular receptors “water-compatible” without having to undertake synthetic modifications. Our results showed that a calix[6]azacryptand-based receptor can be incorporated into DPC micelles, either as a zinc complex or as a polyammonium at low pH. We observed that the zinc complex incorporated in the micelles is able to bind small and long linear primary amines in its cavity and we were able to highlight that complexation is driven by the hydrophobic effect. This work has been reported in the paper “Primary Amine Recognition in Water by a Calix[6]aza-cryptand Incorporated in Dodecylphosphocholine Micelles” Emilio Brunetti, Alex Inthasot, Flore Keymeulen, Olivia Reinaud, Ivan Jabin and Kristin Bartik Org. Biomol. Chem. 2015, 13, 2931-2938.We also validated the micellar incorporation strategy with a homooxacalix[3]tris-acid and with a resorcin[4]arene zinc complex bearing four methyl-imidazole moieties. Once incorporated into DPC micelles, we showed that the two receptors can bind small organic guests: the homooxacalix[3]arene derivative can bind tert-butylammonium or adamantylammonium, albeit with low affinity and the resorcin[4]arene-based zinc complex can bind acetate and acetylacetone.The final part of this thesis is devoted to the work undertaken in order to try and elucidate the guest exchange mechanism of calix[6]arene-zinc complexes where the zinc is tri-coordinated to the calixarene-based ligand and coordinates a guest molecule inside the calixarene cavity. The hypothesis that we put forward is that when the zinc is only tri-coordinated to the calixarene ligand, the guest exchange mechanism involves a zinc penta-coordinated intermediate where the zinc atom is simultaneous coordinated to an endo-complexed guest (inside the cavity) and an exo-complexed molecule (outside the cavity). 1D EXchange SpectroscopY experiments (EXSY) were undertaken with two calix[6]arene-zinc complexes where the zinc is tri-coordinated to the calixarene ligand and with a calix[6]arene-zinc complex where the zinc is tetra-coordinated to the calixarene ligand. The exchange of different guests (ethanol, dimethylformamide and acetonitrile) was monitored in deuterated dichloromethane. We observed that in all cases water accelerates guest exchange but that the guest residence times are highly dependent on the acidity of the metal center and on the nature of the guest buried inside the cavity.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
22
Babazada, Hasan. "Development of heparin nanoparticles:synthesis, physicochemical/biochemical characterization and application to arthritis therapy." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/192149.
Full text
23
Castro, Smirnov Fidel Antonio. "Physicochemical characterization of DNA-based bionanocomposites using nonafibrous clay minerals : biological applications." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112260/document.
Full textAbstract:
Parmi les différents minéraux argileux, la sépiolite, qui est un silicate fibreux naturel, est un potentiel nano-transporteur prometteur pour le transfert non-viral de biomolécules. Il a en effet été montré que la sépiolite interagissait avec des molécules biologiques telles que les lipides, les polysaccharides et les protéines. Dans ce travail, nous démontrons que la sépiolite interagit également efficacement avec différents types de molécules d'ADN (génomique, plasmidique, oligonucléotides simple et double brin), et nous présentons la première étude détaillée sur les mécanismes d'interaction entre la sépiolite et l'ADN, ainsi qu’une caractérisation physico-chimique de bionanocomposites ADN-sepiolite. Une analyse spectroscopique a montré tout d’abord que l’interaction de l'ADN avec la sépiolite était plus forte en présence de polycations, la valence de ces derniers accroissant le rendement d’absorption, et deuxièmement, que l'ADN ainsi adsorbé pouvait être récupéré avec un rendement modulé par la présence d’EDTA, la structure de l'ADN et son activité biologique étant conservées. Par spectroscopie infrarouge à transformée de Fourier (FTIR) nous avons identifié les groupes silanol externes comme les principaux sites d'interaction avec l'ADN. Nous avons ensuite prouvé qu'il est possible d'utiliser la sépiolite pour extraire l'ADN de bactéries, pour la purification de l'ADN et pour la purification de toute contamination bactérienne. En combinant la microscopie à fluorescence, la microscopie électronique à transmission (MET), la vidéo-microscopie et l’analyse par cytométrie en flux (FACS), nous avons montré que la sépiolite peut être spontanément internalisée dans des cellules de mammifère par le biais de deux voies, l’endocytose et la macropinocytose. En tant que preuve de concept, nous montrons que la sépiolite est capable de transférer de manière stable l'ADN de plasmide dans des bactéries et des cellules de mammifères. Il a également été prouvé qu’en incubant des bactéries avec des bionanocomposites ADN-sepiolite, initialement préparés en présence d'une faible concentration en cations divalents et avec de la sépiolite traitée aux ultrasons (sSep), il était possible d'augmenter l'efficacité de la transformation bactérienne 20 à 30 fois par rapport aux méthodes basées sur l'«effet Yoshida». En outre, nous montrons que l'efficacité du transfert de gènes par la sépiolite peut être optimisée : l'utilisation de sSep et l'exposition à la chloroquine augmentent d’un facteur 100 et 2, respectivement, l’efficacité de transfection. Ces résultats ouvrent la voie à l'utilisation de bionanocomposites à base de sépiolite comme de nouveaux potentiels nano-transporteurs hybrides potentiels, à la fois pour la thérapie génique et le développement de nouveaux modèles biologiques en sciences fondamentales et appliquéesAmong the various clay minerals, sepiolite, which is a natural fibrous silicate, isa potential promising nanocarrier for the non-viral transfer of bio-molecules. Indeed,sepiolite has been shown to interact with biological molecules such as lipids,polysaccharides and proteins. Here, we show that sepiolite efficiently binds differenttypes of DNA molecules (genomic, plasmid, single strand and double strandoligonucleotides), introducing the first detailed study on the interaction mechanismsbetween sepiolite and DNA, as well as the physicochemical characterization of theresulting DNA-sepiolite bionanocomposites. The interaction mechanisms aresuggested to be electrostatic interactions, van der Waals forces, cation bridges, andhydrogen bonding. Spectroscopy analysis showed that the binding of DNA to sepiolitewas increased by polycations with valence dependent efficiency, and the DNApreviously adsorbed could be recovered with an efficiency that could be modulatedusing a chelating agent (EDTA), preserving the DNA structure and biological activity.Fourier-transform infrared spectroscopy identified the external silanol groups as themain sites of interaction with the DNA. It was proved that it is possible to use sepiolitefor extracting DNA from bacteria, for DNA purification and for purification from bacterialcontamination. By combining fluorescence microscopy, transmission electronmicroscopy (TEM), time-lapse video microscopy and flow cytometry analysis (FACS),we show that sepiolite can be spontaneously internalized into mammalian cells throughboth endocytic and non-endocytic pathways. As a proof of concept, we show thatsepiolite is able to stably transfer plasmid DNA into bacteria and mammalian cells. Itwas also proved that with the incubation of bacteria with the Sep/DNAbionanocomposite initially prepared in the presence of a low concentration of divalentcation, and using sonicated sepiolite (sSep), it is possible to increase the bacterialtransformation efficiency from 20 to 30-fold compared to previously reported methodswhich are based in the “Yoshida effect”. Additionally, we show that the efficiency ofsepiolite-mediated gene transfer can be optimized: the use of sSep and the exposureto the endosome disrupter chloroquine 100-fold and 2-fold stimulated DNA transfectionefficiency, respectively. These results open the way to the use of sepiolite-basedbionanocomposites as a novel class of hybrid nanocarriers for both potential genetherapy and the development of novel biological models of interest for academic andapplied sciences
24
Santana, Francisco Ferreira [UNESP]. "Caracterização de genótipo de cajazeiras." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/105213.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0
Previous issue date: 2010-05-26Bitstream added on 2014-06-13T20:25:27Z : No. of bitstreams: 1
santana_ff_dr_jabo.pdf: 724307 bytes, checksum: cc386df6e3dcfb323ff1fbe08a11aa54 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A cajazeira quando propagada por sementes apresenta elevada variabilidade genética quanto ao porte, arquitetura, formato da copa, fenologia da planta, características físico-químicas de folhas e frutos e fase juvenil bastante ampla, características não desejáveis para a exploração comercial desta cultura. O método de seleção massal para escolha de genótipos superiores tem sido utilizado com bastante sucesso em fruteiras. Considerando as poucas informações existentes sobre cajazeira, o grande potencial de exploração agroindustrial que esta fruteira apresenta e a necessidade de se preservar o amplo e ainda pouco conhecido patrimônio genético, o presente trabalho teve como objetivo avaliar a variabilidade genética entre 113 genótipos de cajazeiras, pés-francos, através da mensuração das características físicas e químicas para identificar possíveis genótipos com potencial superior e características agronômicas adequadas para recomendação de cultivo. Os dados foram submetidos à análise de variância, pelo teste F, teste de Scott-Knot para as características significativas. As análises de agrupamentos foram realizadas utilizando-se programa para estatísticas multivariadas. Os resultados obtidos permitem afirmar que: todos os genótipos estudados apresentaram elevada variabilidade para as características físicas e químicas, confirmando a possibilidade de obtenção e utilização como matrizes, com atributos superiores; as melhores características tecnológicas e físicas dos frutos foram encontradas nos genótipos F18P2, F11P6, F5P3, F4P11, F15P11 e F14P7; os fatores de produção, número de panículas com frutos e o total de frutos por panícula, são determinantes para a seleção de genótipos de cajazeiras e que os genótipos F14P9 e F14P8 apresentaram as melhores características agronômicas para seleção de genótipos com melhor produtividade
The yellow mombin when propagated by seed has high genetic variability of size, architecture, form of canopy, plant phenology, physical and chemical characteristics of leaves and fruits and juvenile phase, undesirable characteristics for commercial exploration of this crop. The method of mass selection in order to choose superior genotypes has been used quite successfully in fruit crops. Considering the little information available concerning the yellow mombin, the large potential for agroindustrial exploration that this fruit has and the need to preserve the broad and still little genetic heritage, this study aims to evaluate the genetic variability between the 113 genotypes of the yellow mombin, seedlings, by measuring the physical, physicochemical characteristics and identify these possible genotypes with higher potential and agronomic traits suitable for cultivation recommendation. The data were subjected to analysis of variance by F test, Scott-Knott test for significant features. The cluster analysis was performed have revealed that all genotypes showed high variability for the possibility of obtaining matrices with superior attributes; the best technological and physical characteristics of fruits were found in F18P2, F11P6, F5P3, F4P11, F15P11 and F14P7 genotypes; factors of production, number of panicles with fruit and total fruit per panicle, are decisive for the selection of yellow mombin genotypes and F14P9 and F14P8 showed the best agronomic traits for selecting genotypes with improved productivity
25
Santana, Francisco Ferreira. "Caracterização de genótipo de cajazeiras /." Jaboticabal : [s.n.], 2010. http://hdl.handle.net/11449/105213.
Full textAbstract:
Resumo: A cajazeira quando propagada por sementes apresenta elevada variabilidade genética quanto ao porte, arquitetura, formato da copa, fenologia da planta, características físico-químicas de folhas e frutos e fase juvenil bastante ampla, características não desejáveis para a exploração comercial desta cultura. O método de seleção massal para escolha de genótipos superiores tem sido utilizado com bastante sucesso em fruteiras. Considerando as poucas informações existentes sobre cajazeira, o grande potencial de exploração agroindustrial que esta fruteira apresenta e a necessidade de se preservar o amplo e ainda pouco conhecido patrimônio genético, o presente trabalho teve como objetivo avaliar a variabilidade genética entre 113 genótipos de cajazeiras, pés-francos, através da mensuração das características físicas e químicas para identificar possíveis genótipos com potencial superior e características agronômicas adequadas para recomendação de cultivo. Os dados foram submetidos à análise de variância, pelo teste F, teste de Scott-Knot para as características significativas. As análises de agrupamentos foram realizadas utilizando-se programa para estatísticas multivariadas. Os resultados obtidos permitem afirmar que: todos os genótipos estudados apresentaram elevada variabilidade para as características físicas e químicas, confirmando a possibilidade de obtenção e utilização como matrizes, com atributos superiores; as melhores características tecnológicas e físicas dos frutos foram encontradas nos genótipos F18P2, F11P6, F5P3, F4P11, F15P11 e F14P7; os fatores de produção, número de panículas com frutos e o total de frutos por panícula, são determinantes para a seleção de genótipos de cajazeiras e que os genótipos F14P9 e F14P8 apresentaram as melhores características agronômicas para seleção de genótipos com melhor produtividadeAbstract: The yellow mombin when propagated by seed has high genetic variability of size, architecture, form of canopy, plant phenology, physical and chemical characteristics of leaves and fruits and juvenile phase, undesirable characteristics for commercial exploration of this crop. The method of mass selection in order to choose superior genotypes has been used quite successfully in fruit crops. Considering the little information available concerning the yellow mombin, the large potential for agroindustrial exploration that this fruit has and the need to preserve the broad and still little genetic heritage, this study aims to evaluate the genetic variability between the 113 genotypes of the yellow mombin, seedlings, by measuring the physical, physicochemical characteristics and identify these possible genotypes with higher potential and agronomic traits suitable for cultivation recommendation. The data were subjected to analysis of variance by F test, Scott-Knott test for significant features. The cluster analysis was performed have revealed that all genotypes showed high variability for the possibility of obtaining matrices with superior attributes; the best technological and physical characteristics of fruits were found in F18P2, F11P6, F5P3, F4P11, F15P11 and F14P7 genotypes; factors of production, number of panicles with fruit and total fruit per panicle, are decisive for the selection of yellow mombin genotypes and F14P9 and F14P8 showed the best agronomic traits for selecting genotypes with improved productivity
Orientador: Antonio Baldo Geraldo Martins
Coorientador: José Carlos Barbosa
Banca: José Antonio Alberto da Silva
Banca: Leila Trevizan Braz
Banca: Simone Rodrigues da Silva
Banca: Luiz Evaldo de Moura Pádua
Doutor
26
Ramírez, Garcia Gonzalo. "Physicochemical characterization and biocompatibility studies of persistent luminescence nanoparticles for preclinical diagnosis applications." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066370/document.
Full textAbstract:
Les nanoparticules (NPs) à luminescence persistante de gallate de zinc dopée chrome (ZnGa1.995Cr0.005 O4) sont des matériaux innovants avec des propriétés optiques particulières qui permettent leur utilisation pour l'imagerie optique in vivo. Leur caractérisation a été effectuée par une méthode émergente dans ce domaine, l'électrophorèse capillaire. Les résultats ont démontré le potentiel de cette méthode pour garantir le contrôle et la qualité des NPs. Un ensemble général des tests de toxicité a été réalisé in vitro et in vivo après administration aiguë, à court et à long terme des ZnGa1.995Cr0.005O4, afin d'évaluer leur biocompatibilité. Lors de l'administration de NPs hydroxylés, différentes conséquences négatives ont été notées, ainsi comme l'effet protecteur du polyéthylène glycol fonctionnalisé en surface des NPs. En raison de l'importance des interactions des NPs avec les protéines plasmatiques lors de leur administration, nous avons évalué et appliqué pour la première fois la méthode électrocinétique de Hummel-Dreyer pour la détermination des interactions non spécifiques entre les NPs PEGylés et des protéines. Finalement, l'évaluation des interactions entre les ZnGa1.995Cr0.005O4 et un système binaire de protéines (albumine et Apolipoprotéine-E) a été effectuée par des méthodes électrocinétiques. Ces analyses ont montré une affinité plus forte entre la surface des NPs PEGylés et l'apolipoprotéine-E par rapport à l'albumine, ce qui pourrait représenter une stratégie novatrice pour la vectorisation des NPs vers la région du cerveau. Toutes les méthodes mentionnées ci-dessus peuvent être extrapolées pour l'analyse des autres NPs avec plusieurs des applicationsThe chromium doped zinc gallate (ZnGa1.995Cr0.005O4) nanoparticles (NPs) are innovative materials with specific optical properties, notably the persistent luminescence, which allow their use for in vivo optical imaging. Their characterization was carried out by an emergent method in this area, the capillary electrophoresis. The obtained results demonstrated the potential of this method to ensure the control and quality of NPs. A general set of toxicity tests were performed in vitro and in vivo after acute, short- and long-term administration of the NPs to assess their biocompatibility. Various negative effects were noted upon administration of hydroxylated NPs, as well as the protective effect of NP PEGylation. Because of the importance of NP interactions with plasma proteins after their in vivo administration, we evaluated and applied for the first time the Hummel-Dreyer electrokinetic method for the determination of non-specific interactions between PEGylated NPs and proteins. Finally, the evaluation of the interactions between the ZnGa1.995Cr0.005O4 and a binary system of proteins (albumin and apolipoprotein-E) was carried out by electrokinetic methods. The results revealed greater affinity between the surface of the PEGylated NPs and the apolipoprotein-E compared to albumin, which could represent a novel strategy for the vectorization of NPs towards the brain region. All the above mentioned methods can be extrapolated for the analysis of other NPs with several potential applications
27
Abankwa, Gladys V. "Functional, biological and physicochemical characterization of alveolar hydatid cyst-induced amyloid enhancing factor." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66252.
Full text
28
Sueros, Velarde Felix Jose. "Synthesis, characterization and physicochemical properties of novel derivatives of calix(n)arenes (n=4,6,8)." Thesis, University of Surrey, 1996. http://epubs.surrey.ac.uk/843321/.
Full textAbstract:
Following an overview on the progress so far made in the general area of calixarene chemistry, this thesis reports investigations related to i) the acid-base properties of p-tert-butycalix[n]arenes (n=4,6,8) and amines (trimethylamine, tert-butylamine, atropine, 1-aminoadmantane, morpholine, R-(+)-alpha-methylbenzylamine, piperazine, cryptands 22 and 222) in benzonitrile at 298.15 K and their implications on the proton transfer reaction from the calixarene to the amine. Fom experimental data, the individual processes which contribute to the overall extraction of tert-butylamine from water by p-tert-butylcalix[8]arene in benzonitrile were quantitatively assessed. ii) the use of phase transfer catalysis for the synthesis of ethy p-tert-butycalix[n]arene (n=4,6,8) ethanoates. Advantages with respect to current preparative methods are outlined. The stability constant of sodium and ethyl p-tert-butylcalix[4]arene tetraethanoate in acetonitrile at 298.15 K was determined by direct potentiometry using an ion-selective electrode. The result obtained, is in good agreement with that recently reported from a double competitive potentiometric method. Extraction data in the water-benzonitrile solvent system at 298.15 K were used to quantitatively evaluate for the first time the individual processes involved in the overall extraction of alkali-metal picrates by ethy p-tert-butycalix[4]arene tetraethanoate. iii) the synthesis and characterization of new calixarene derivatives obtained by the lower rim functionalization of p-tert-butycalixarense by the introduction of a) N,N-dimethylcarbamoyl and N-acetylglycine groups using phase transfer catalysts (18-crown-6,4- dimethylaminopyridine and 1,3-dicyclohexylcarbodiimide). In both cases, disubstituted calixarene derivatives were obtained in distorted cone conformations, b) aliphatic (methyl, ethyl, isopropyl), alicyclic (piperidine, pyrrolidine, morpholine) and aromatic (quinoline, pyridine) amino groups. These were characterized by elemental analysis, 1H and 13C NMR spectroscopy. The acid-base properties of these derivatives were investigated in methanol. The ability of these ligands in their neutral and protonated forms to interact with cations and anions; respectively, is discussed. Final conclusions of these investigations are summarized and suggestions for further work are given.
29
Godbout, Chris. "Poly(ethylene glycol-co-lactic acid) block copolymer micelles : synthesis, physicochemical characterization, and degradation." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101129.
Full textAbstract:
The goal of this thesis was to synthesize two poly(lactic acid)-co-poly(ethylene glycol) biodegradable amphiphilic block copolymers that can self-assemble in an aqueous environment into a micellar morphology. Also, the physicochemical characteristics of both the copolymers and resultant micelles were studied using a variety of chemical characterization techniques to gain insight into the factors that are important in the formation and function of the micelles. Two copolymers were synthesized which had different sizes and relative block lengths. These copolymers were characterized using NMR spectroscopy, gel permeation chromatography and thermogravimetric analysis. With these two polymers the self-assembly conditions which lead to the most narrow size distribution as determined by dynamic light scattering, were found and micelles were characterized by scanning electron microscopy, and through the partitioning of pyrene between the core of the micelles and water. Finally, an investigation of the time scales of micelle degradation was performed by monitoring a solution of micelles over an extended period of time.
30
Ansah, Yaw Boamah. "Characterization of pond effluents and biological and physicochemical assessment of receiving waters in Ghana." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31948.
Full textAbstract:
This study was carried out to characterize ponds and aquaculture systems, and also to determine both the potential and actual impacts of pond aquaculture effluents on receiving stream quality in the Ashanti and Brong Ahafo regions of Ghana. Water, fish and macroinvertebrate samples were collected from upstream, downstream and nearby reference streams of, and questionnaires administered to, 32 farms. Total settleable solids were higher in ponds than reference streams (p = 0.0166); suspended solids was higher in ponds than reference streams (p = 0.0159) and upstream (p = 0.0361); and total phosphorus was higher in ponds than reference (p = 0.0274) and upstream (p = 0.0269). Total nitrogen was most clearly higher in ponds than all other locations: p = 0.0016, 0.0086 and 0.0154 for the differences between ponds and reference, upstream, and downstream respectively. BOD5 level was also higher in ponds than all locations (p = 0.0048, 0.0009, and 0.0012 respectively). Also, non-guarding fish species were more abundant in reference streams than downstream (p = 0.0214) and upstream (p = 0.0251), and sand-detritus spawning fish were less predominant in reference streams than upstream (p = 0.0222) and marginally less in downstream locations (p = 0.0539). A possible subsidy-stress response within study streams was also observed. Hence, ponds are potential sources of these water quality variables to receiving streams. Effluent-receiving streams, generally, were not much different from reference streams in terms of most the metrics of community structure and function used in the comparisons. Hence, even though receiving streams in Central Ghana may not be severely impacted by aquaculture effluents at the moment, the management of pond effluents will determine the scale of future impact. Vegetable, cereal, and livestock farming could serve as additional sources of fecal streptococci and coliform bacteria and nutrient-enrichment within the study area, besides aquaculture, and so these industries must also be included in efforts to minimize pollution of these streams.Master of Science
31
Tadanier, Christopher J. "Influence of Operational Characterization Methods on DOM Physicochemical Properties and Reactivity with Aqueous Chlorine." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/40503.
Full textAbstract:
The physicochemical properties and chemical reactivity of dissolved organic matter (DOM) are of tremendous practical significance in both natural and engineered aquatic and terrestrial systems. DOM is frequently extracted, fractionated, and concentrated from environmental samples using a variety of operationally defined physical and chemical processes in order to facilitate study of specific physicochemical properties and aspects of its chemical reactivity. This study was conducted to systematically examine the influence of operationally defined physical and chemical characterization methods on observed DOM physicochemical properties and reactivity with aqueous chlorine. The effects of chemical separation were evaluated by applying an existing resin adsorption based procedure which simultaneously extracts and fractionates DOM and inorganic constituents into hydrophobic and hydrophilic acid, base, and neutral dissolved material matrix (DMM) fractions. Physical separation based on DOM apparent molecular weight (AMW) was also evaluated using batch ultrafiltration (UF) data in conjunction with a suitable membrane permeation model. Linear independence of membrane solute transport was theoretically described using non-equilibrium thermodynamics and experimentally demonstrated for AMICON® YC/YM series UF membranes. Mass balances on DMM fraction constituents in untreated and previously coagulated natural waters indicated that quantitative recovery (100 ± 2%) of DOM constituents was achieved, while recovery of inorganic constituents such as iron and aluminum was substantially incomplete (30%-74%). Comparison of whole-water DOM properties with those mathematically reconstituted from DMM fractions demonstrated a marked shift in DOM properties toward lower AMW. Evidence of pH induced partial hydrolysis of protein, polysaccharide, and ester DOM components was also observed. Decreased specific Cl2 demand (mmol DCl2/ mmol DOM) and specific trihalomethane formation (mmol THM/mmol DOM) following chemical fractionation were attributed to increased molar DOM concentration and decreased DOM association with colloidal iron oxide surfaces. Collectively, the results of this research indicate that operational characterization methods result in alteration of DOM physicochemical properties and reactivity with aqueous chlorine, and caution is therefore advisable when interpreting the results of studies conducted using chemically extracted or fractionated DOM.Ph. D.
32
Mühlbauer, Andrea. "Synthesis and physicochemical characterization of novel biocompatible ionic liquids for the solubilization of biopolymers." Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10203.
Full textAbstract:
Dans le contexte de la chimie verte, on trouve des solvants alternatifs, comme les liquides ioniques (LIs) et les eutectiques profonds (DESs). L'objectif de la thèse était de développer de nouveaux LIs et DESs biocompatibles pour la solubilisation de biopolymères (e.g. cellulose). Les alkylammonium quaternaires à chaîne courte (C3 à C6) bi- et tricaténaires associés à divers carboxylates d'origine naturelle se sont révélés être de bons candidats et ont permis d'identifier les effets structuraux clés pour la solubilisation de la cellulose. Par cette approche systématique couplée à une étude physicochimique approfondie des LIs, les lévulinates de [DiC3], [DiC4] et [TriC4] et l’itaconate de [DiC4] sont les plus efficaces et permettent de solubiliser jusqu'à 10 % de cellulose, voire 20% en présence d'un co-solvant biosourcé, la g-valérolactone. Dans un second temps, ils ont été substitués par des cations biocompatibles dérivés de la choline, de la bétaïne et de la carnitine, associés aux carboxylates précédents. Les dérivés de type éther et ester sont des LIs et l'éthyl-choline éther lévulinate permet de solubiliser 10% de cellulose. En melange avec l'urée, les sels de dibutylammonium et les esters de bétaïne se comportent comme des DESs dont les températures de fusion sont de l'ordre de 30 à 40 °C. De même, des DESs à base de dérivés de sucre possédant une fonction éther sur le carbone anomérique ont été obtenus en présence des sels de choline, de bétaïne et de carnitine. Enfin, une approche théorique utilisant le logiciel COSMO-RS a été utilisée pour la modélisation des propriétés des LIs et des DESs ainsi que pour la solubilisation de la cellulose afin de la prédireIn th context of green chemistry, there are alternative solvents, such as ionic liquids (ILs) and deep eutectic solvents (DESs). The aim of the thesis was to development of new biocompatible ILs and DESs for the solubilization of biopolymers, such as cellulose. Short-chain two- and three-tailed quaternary alkylammonium (C3 - C6) associated with various biosourced carboxylates have been good candidates and the identification of structural key factors for cellulose solubilization was realizable. This systematic approach coupled with extensive physicochemical study of ILs, resulted in the levulinates of [DiC3 ], [DiC4] and [TriC4] and [DiC4]itaconate as the most efficient with a solubilization of cellulose up to 10 %, or even 20 % in the presence of the bio-based co-solvent g-valerolactone. Despite their good biodegradability in comparison with that of imidazolium, quaternary ammonium are not naturally resourced. They were therefore, in a second step, substituted by derivatives of choline, betaine and carnitine as biocompatible cations, associated with the above carboxylates. The ether- and ester-derivatives are ILs, and ethyl-choline ether levulinate is able to solubilize 10 % cellulose. Moreover, urea combined with dibutylammonium salts or betaine esters behave as DESs with melting temperatures around 30 to 40 °C. In the same way, DESs based on sugar-derivatives having an ether function on the anomeric carbon has been obtained in the presence of salts of choline, betaine and carnitine. Finally, a theoretical approach using the COSMO-RS software was used to model the properties of ILs and DESs and for predictions of cellulose solubilization
33
Madsen, Benjamin R. "Characterization and Physicochemical Modifications of Polymer Hollow Fiber Membranes for Biomedical and Bioprocessing Applications." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/577.
Full textAbstract:
Hollow fiber membranes (HFMs) formed through phase inversion methods exhibit specific physicochemical characteristics and generally favorable surface and mechanical properties, supporting their use in diverse applications including ultrafiltration, dialysis, cell culture, bioreactors, and tissue engineering. Characterization of, and modifications to, such membranes are important steps in achieving desired characteristics for specific applications. HFMs subject to gas, irradiation, and chemical sterilization techniques were characterized based on several analytical techniques. It was revealed that these common sterilization techniques can cause inadvertent changes to HFM properties. While these changes may cause detrimental effects to HFMs used in filtration, the methods of sterilization are also presented as a facile means of tuning properties toward specific applications. Modifications to HFM surface chemistries were also sought as a method of adsorbing bacterial lipopolysaccharide (LPS) from solutions used in hemodialysis treatments and bioprocessing applications. It was found that additives such as polyvinylpyrrolidone (PVP), polyethyleneglycol (PEG), and poly-L-lysine (PLL) can facilitate adsorption capacities of HFMs toward LPS. Additionally, chemical changes are presented as a means of preferentially adsorbing LPS to specific locations on the HFM surface.
34
Morozzi, Pietro <1993>. "Innovative methods for physicochemical and dynamic characterization of ambient aerosols and other environmental systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10061/1/Tesi_PhD_Morozzi_Pietro.pdf.
Full textAbstract:
The present Thesis reports the main scientific achievements in my PhD research activity based on the application of multivariate statistical methods for Environmental Chemistry (academic discipline: CHIM/12) and, in particular, in the treatment of atmospheric aerosols data. During the three-year PhD period, I have faced several topics which have led to the publication of eight scientific articles including three as the first author. My publications can be conceptually grouped into three distinct parts:
1) Design and optimization of innovative experimental methodologies for the analysis of Airborne Particulate Matter (PM) and data interpretation, as related to human health, air quality, and climate change.
2) Definition of practical guidelines and optimal use of PM low-cost sensors based on the Optical Particle Counting (OPC) developed on laser scattering devices.
3) Analysis of other environmental matrices (different from airborne particulate matter) and data interpretation.
Furthermore, this Thesis describes the preliminary results of other research work presently in progress including:
1) Physico-chemical and meteorological characterization of atmospheric aerosols in southern Spain as part of the FRESA project.
2) Study and characterization of the processes and dynamics of atmospheric aerosol in the touristic Pertosa-Auletta cave (Italy, SA).
3) Characterization and quantification of radionuclides in innovative building materials defined as “Geopolymers”.
The common thread of all my scientific investigation is multivariate statistics for environmental assessment purposes. Multivariate Statistics includes all the mathematical-statistical methods to study complex sets of data, a typical situation in environmental chemistry, in order to extract tangible and exhaustive quali-quantitative information. The term Chemometrics is going to often be used in this Thesis to indicate mathematical-statistical methods applied to Chemistry.
35
Park, Yong Bok. "Studies on Hog Plasma Lecithin:cholesterol Acyltransferase: Isolation and Characterization of the Enzyme." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc331699/.
Full textAbstract:
Lecithin:cholesterol acyltransferase (LCAT) was isolated from hog plasma and basic physicochemical properties and functionally important regions were investigated. Approximately one milligram of the enzyme was purified to apparent homogeneity with approximately a 20,000-fold increase in specific activity. In the plasma, hog LCAT was found to associate with high-density lipoproteins (HDL) probably through hydrophobic interactions with apolipoprotein A-I. HDL was the preferred lipoprotein substrate of the enzyme as its macromolecular substrate. The enzyme was found to contain 4 free sulfhydryl groups; at least one of these appeared to be essential for catalytic activity. The enzyme had a tendency to aggregate at high concentrations. More than half of the tryptophan and none of the tyrosine residues of the enzyme were shown to be exposed to the aqueous environment based on fluorescence and absorbance studies, respectively.
36
Joseph, Michael Vadakekara. "Extrusion, physico-chemical characterization and nutritional evaluation of sorghum-based high protein, micronutrient fortified blended foods." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32907.
Full textAbstract:
Doctor of PhilosophyDepartment of Grain Science and Industry
Sajid Alavi
The feasibility of using a wheat flour mill to refine corn, sorghum and cowpea was studied. Milling of white sorghum grain resulted in decrease in fiber content from 1.89% to 0.38% and 0.45% in raw, finely milled and coarsely milled sorghum respectively. Similarly, there was a reduction in fat (3.17% to 1.75% and 0.51%) content from raw to fine and coarse milled fractions. Starch content increased from 61.85% in raw to 69.80% in fine and 72.30% in coarse fractions. Protein content was almost unchanged at about 7.40% in all the fractions. In de-hulling and milling of cowpeas, starch and protein content increased whereas fiber, fat and ash content decreased. There was a significant difference in expansion characteristics between whole and decorticated binary blends on account of different levels of inherent starch content. Sorghum cowpea (SC) blends had the highest specific mechanical energy (SME) range (285.74 – 361.52 kJ/kg), followed by corn soy (CS) (138.73 – 370.99 kJ/kg) and the least SME was found in sorghum soy (SS) blends (66.56 – 332.93 kJ/kg). SME was found to be positively correlated to starch content in the blends. SC blends had the most stable process followed by SSB and CSB in that order. The milling of expanded extrudates was found to be dependent on bulk density and low bulk density extrudates had bigger particle size and vice-versa. The water absorption index (WAI) for SC was 4.17 g/g to 5.97 g/g, SS ranged from 2.85 g/g to 5.91 g/g and CS ranged from 2.63 g/g to 5.40 g/g. Starch gelatinization ranged from 85.42 – 98.83% for SC, 90.70 – 96.27% for SS, and 72.57 – 95.49% for CS. The starch digestibility increased after extrusion and cooking but there was no significant change in protein digestibility. There was a significant reduction in anti-nutritional factors – phytic acid (26.06 – 44.03%), tannins (18.69 – 26.67%) and trypsin inhibitor (16.55 – 50.85%) after extrusion. Thus, the study showed that high protein blends with superior nutrition density needed for preparation of FBFs could be produced by using existing/traditional milling capabilities and extrusion process.
37
Amaral, Fabiano Pereira do [UNESP]. "Estudo das características físico-químicas dos óleos da amêndoa e polpa da macaúba [Acrocomia aculeata (Jacq.) Lodd. ex Mart]." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/90468.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:24:39Z (GMT). No. of bitstreams: 0
Previous issue date: 2007-12-17Bitstream added on 2014-06-13T20:52:17Z : No. of bitstreams: 1
amaral_fp_me_botfca.pdf: 322336 bytes, checksum: 734946ffb373e6bcd1a5815e121a7e24 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A conjuntura energética internacional aponta para o esgotamento das reservas de petróleo em curto prazo. O Brasil, face às suas potencialidades, tem procurado através de políticas públicas, incentivar o estudo de formas alternativas de energia. Muitas destas formas são baseadas em produtos e sub-produtos agrícolas, com destaque para a indústria de álcool para fins combustíveis. Outra alternativa de origem vegetal, mais recentemente discutida, seria a produção de óleo combustível denominado biodiesel. Para este fim, iniciativas tem sido tomadas em nível internacional, já sendo possível a obtenção e uso deste combustível de forma comercial. Em nossa região, muitas plantas oleaginosas podem ser potencialmente exploradas para esta finalidade, cujo potencial tem sido pouco estudado. Este trabalho dedica-se ao estudo de uma espécie oleaginosa, a macaúba [Acrocomia aculeata (Jacq) Lodd. ex Mart], para verificar seu potencial energético e econômico. Para este fim, foram realizadas diferentes caracterizações físico-químicas nos constituintes do fruto da macaúba, incluindo a avaliação qualitativa do óleo da polpa e da castanha. Verificou-se que esta espécie apresenta boas características como fonte de óleo vegetal para fins energéticos e/ou industriais, comparável e até superior a outras oleaginosas. Verificou-se que os parâmetros físico-químicos indicam que a espécie é importante como fonte energética, principalmente baseado nos valores calorimétricos. As análises cromatográficas revelaram que os óleos da macaúba podem ser distintamente empregados, com potencial energético para o óleo da polpa e farmacológico para o óleo da amêndoa.
The international energetic context shows a run out of fuel reserve in a short term. Brazil due to its natural resources has tried through public politics to stimulate the research of alternative ways of energy. Several of these ways are based upon agricultural products and by-products with emphasis on the alcohol-fuel industry. Another alternative from plants recently discussed would be the production of biodiesel fuel. Initiatives have been internationally performed in order to obtain and use such fuel commercially. Within our region several oil plants can be potentially explored and have also been researched. This work aims to study an oil plant – macaúba [Acrocomia aculeata (Jacq) Lodd. ex Mart] to analyze its energetic and economical potential. Different physicochemical characterization was performed in macaúba plant including quality evaluation of its oil from pulp and nut. It was observed that such plant shows good characteristics as a source for plant oil for energetic and/or industrial uses being superiorly compared to other oil plants. It was also verified that the physicochemical parameters for this species indicate her importance as energetic source, considering its calorimetric values. The chromatographic analysis revealed that the macauba oils could be used for different purposes, like energetic potential for the pulp oil or pharmaceutical uses for the nut oil.
38
Fonseca, Ana Carolina Moreira. "Processos de obtenção e caracterização físico-química de quitinas e quitosanas extraídas dos rejeitos da indústria pesqueira da região de Cananéia - SP." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-22082016-160017/.
Full textAbstract:
A quitina é o principal produto obtido do processamento das cascas de crustáceos. Esse biopolímero e o seu derivado, quitosana, têm despertado grande interesse comercial em virtude das possibilidades de aplicações que possuem. O gerenciamento desses resíduos e dos subprodutos gerados nas etapas no processo de obtenção pode ser considerado um modelo de biorrefinaria. A implementação de plantas para extração de quitina e quitosana é um desafio, uma vez que a demanda produtiva deve ser atendida sem causar danos ao meio ambiente. Uma grande variedade de quitosanas com diferentes propriedades físicoquímicas podem ser obtidas variando-se as condições de reação. Essas propriedades dependem da origem da matéria-prima, do seu grau médio de desacetilação, distribuição média dos grupos acetil ao longo da cadeia principal e da sua massa molecular média. Os fornecedores de quitosana comercial geralmente não mencionam a procedência da matéria-prima e pouca ou nenhuma informação é fornecida acerca do seu processamento. Sendo assim, as características e a reatividade do produto final podem variar gerando resultados não reprodutíveis. No presente estudo, foi utilizada a biomassa oriunda de rejeitos da indústria pesqueira de camarão da região de Cananéia SP. As amostras de - quitina foram obtidas por dois procedimentos diferentes: no primeiro, P1, as cascas de camarão após passar pelo pré-tratamento (lavagem, secagem e moagem) foram desproteinizadas para retirada das proteínas em hidróxido de sódio (NaOH) diluído nas concentrações 2%, 5% e 10% e desmineralizadas em ácido clorídrico (HCl) a 20% (v/v) para retirada dos carbonatos; no segundo procedimento, P2, essas etapas foram invertidas. A biomassa resultante foi desacetilada com hidróxido de sódio concentrado a 30%, 40% e 50% em tempos que variaram de 2 a 6 horas. As principais propriedades físico-químicas das amostras de quitosanas obtidas foram determinadas utilizando a espectroscopia na região do infravermelho com transformada de Fourier (FT-IR) para a determinação do grau médio de acetilação, GA, e a técnica de titulação ácido-base mensurada por condutimetria foi utilizada para comparar os resultados; a viscosimetria capilar para a determinação da massa molar média viscosimétrica, Mv , e a difração de raios X (DRX) para avaliar o grau médio de cristalinidade, X. Além disso, foram empregadas as técnicas de microscopia eletrônica de varredura (MEV) para análises morfológicas dos materiais obtidos e a espectrometria de fluorescência de raios X por dispersão de comprimento de onda (WDXRF) para análise química das quitosanas. O GA e o X das amostras diminuíram à medida em que o tratamento se tornou mais vigoroso, enquanto a Mv aumentou. O procedimento 2 foi o mais viável por eliminar a etapa de despigmentação, pois originou amostras com tonalidade mais clara e fáceis de pulverizar.Chitin is the main product obtained from the processing of crustacean shells. This biopolymer and its derivative, chitosan, have aroused great commercial interest because of the possibilities of applications they have. The management of these wastes and by-products generated in the steps of obtaining processes can be considered a biorefinery model. The implementation of plants for chitin and chitosan extraction is a challenge, since the production demand must be met without causing harm to the environment. A wide variety of chitosan with different physico-chemical properties can be obtained by varying the reaction conditions. These properties depend on the origin of the raw material, its average degree of deacetylation average distribution of the acetyl groups along the backbone and its average molecular weight. Chitosan commercial providers generally do not mention the origin of the raw material and few or no information is provided about the processing. Therefore, the characteristics and reactivity of the final product may vary generating non-reproducible results. The biomass coming from the fishing industry tailings shrimp Cananéia - SP region was used in the present study. Samples of -chitin were obtained by two different procedures: the first, P1, the shrimp shells after passing through the pretreatment (rinsing, drying and grinding) were deproteinized for removal of proteins in diluted sodium hydroxide (NaOH) in concentrations 2%, 5% and 10% and demineralized in hydrochloric acid (HCl) to 20% (v/v) to remove carbonates; in the second procedure, P2, these steps were reversed. The resulting biomass was deacetylated with sodium hydroxide concentrated at 30%, 40% and 50% in times ranging from 2 to 6 hours. The main physicochemical properties of chitosan samples obtained were determined using Fourier transform infrared spectroscopy (FT-IR) to determine the average degree of acetylation, DA, and the acid-base titration technique measured by conductimetry was used to compare the results of chitosan; capillary viscometry to determine the viscosimetric average molecular weight, Mv, and X-ray diffraction (XRD) to evaluate the average degree of crystallinity, X. In addition, scanning electron microscopy (SEM) were employed for morphological analyzes of the obtained materials and wavelength dispersion X-ray fluorescence (WDXRF) for chemical analysis of chitosan. The DA and X of the samples decreased as the treatment became stronger, while Mv increased. Procedure 2 was the most feasible to eliminate the depigmentation step because gave clearer and easier samples spraying.
39
Bruxel, Fernanda. "Adsorção de oligonucleotídeos com atividade antimalárica em nanoemulsões : validação de método analítico e caracterização físico-química." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/15020.
Full textAbstract:
Nanoemulsões catiônicas têm sido consideradas como potenciais sistemas carreadores para oligonucleotídeos (ON) antisenso. O objetivo do presente trabalho foi desenvolver nanoemulsões catiônicas como um sistema de liberação para ON anti-topoisomerase II de Plasmodium falciparum. Primeiramente, nanoemulsões constituídas de triglicerídeos de cadeia média, lecitina de gema de ovo, glicerol e água contendo os lipídeos catiônicos oleilamina ou DOTAP (2 mM) foram obtidas através do procedimento de emulsificação espontânea. Este procedimento resultou em formulações monodispersas com diâmetro de gotícula de 200-260 nm e potencial zeta de +50 e +55 mV. Após, um método espectrofotométrico no UV para quantificação dos ON em série fosfodiéster (PO) ou fosforotioato (PS) foi validado. O método mostrou-se linear, específico, preciso e exato para a determinação de PO e PS, sem diferenças significativas entre os ON. Nas condições validadas, as isotermas de adsorção dos ON às nanoemulsões foram obtidas através da determinação dos ON na fase aquosa externa das nanoemulsões, após ultrafiltração/centrifugação dos complexos. A taxa de recuperação através das membranas de ultrafiltração de celulose regenerada (30 kDa) foi superior a 92%. Os resultados indicam a adsorção progressiva dos ON com as nanoemulsões, até cerca de 60 mg/g de fase interna para o complexo DOTAP-PS. Finalmente, evidências adicionais da adsorção de PO e PS às nanoemulsões foram detectadas pelo aumento do diâmetro de gotícula, inversão do potencial zeta e morfologia das gotículas avaliada por microscopia eletrônica de transmissão. O conjunto dos resultados obtidos demonstra que ON de série PO e PS anti-topoisomerase II de P. falciparum podem ser adsorvidos eficientemente às nanoemulsões catiônicas.Cationic nanoemulsions have been recently considered as a potential delivery system for antisense oligonucleotides (ON). The aim of the present work was to evaluate cationic nanoemulsions as a delivery system for ON against the Plasmodium falciparum topoisomerase II gene. Firstly, nanoemulsions composed of medium chain triglycerides, egg yolk lecithin, glycerol and water, containing the cationic lipids oleylamine or DOTAP (2 mM) were obtained through spontaneous emulsification process. This procedure resulted in monodisperse formulations with droplet size of 200-260 nm and zeta potential of +50 and +55mV. After that, an UV spectrophotometric method for the quantification of either phosphodiester (PO) or phosphorothioate (PS) ON was validated. The method was linear, specific, precise, and accurate for the determination of PO and PS, without significant differences between both ON. In the validated conditions, ON adsorption isotherms with nanoemulsions were obtained through the ON determination in the external phase of nanoemulsions, after ultrafiltration/centrifugation of complexes. The recovery through regenerated cellulose membranes (30kDa) was higher than 92%. The results showed a progressive ON adsorption to the nanoemulsions up to approximately 60mg/g of internal phase for DOTAP-PS complexes. Finally, additional evidences of PO and PS adsorption to nanoemulsions could also be detected by the increase of the mean droplet size, the inversion of the zeta potential and the morphology of the oil droplets obtained by transmission electron microscopy. The overall results showed that PO and PS ON against P. falciparum anti-topoisomerase II gene can be efficiently adsorbed to the cationic nanoemulsions.
40
Nakashima, Gabriela Tami. "Use of sugarcane trash for solid biofuel production: physicochemical characterization and influence of storage time." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8955.
Full textAbstract:
Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-08-09T12:48:03Z
No. of bitstreams: 1
NAKASHIMA_Gabriela_2016.pdf: 18948386 bytes, checksum: c4adf2165784091a5371108a8c2bd529 (MD5)Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-09T12:48:12Z (GMT) No. of bitstreams: 1 NAKASHIMA_Gabriela_2016.pdf: 18948386 bytes, checksum: c4adf2165784091a5371108a8c2bd529 (MD5)
Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-09T12:48:18Z (GMT) No. of bitstreams: 1 NAKASHIMA_Gabriela_2016.pdf: 18948386 bytes, checksum: c4adf2165784091a5371108a8c2bd529 (MD5)
Made available in DSpace on 2017-08-09T12:48:26Z (GMT). No. of bitstreams: 1 NAKASHIMA_Gabriela_2016.pdf: 18948386 bytes, checksum: c4adf2165784091a5371108a8c2bd529 (MD5) Previous issue date: 2016-04-29
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
In the sugarcane plantation it was common to use fire to facilitate the cutting and harvesting of sugarcane. However, Law 11,241 / 02 in São Paulo State provides the gradual elimination of this straw burning of sugarcane. The largest producer of sugarcane in Brazil is the São Paulo State, which has about 4.7 million hectares of planted area. It is estimated that one hectare produces about 14 tons of trash. Therefore, the mills have been trying to incorporate this trash in burning with the bagasse for power generation. However, high concentrations of mineral impurities are impossible its use for energy purposes. The aim of the study was to investigate the influence of storage time and particle size in the physicochemical characterization of the sugarcane trash. It was used the sugarcane trash inside and outside of the bale collected at different storage time (0, 1 and 2 years). The collected material was separated into four different particle sizes (> 0.420mm, 0.250-0.420mm, < 0.250mm and mix). The analyzes involved particle size distribution, proximate analysis, the high heating value (HHV), the chemical analysis of the components of the ashes, the images in the Scanning Electron Microscope (SEM), the Klason lignin content, the holocellulose content and extractives. There were variations in the results of the ash content with different particle sizes. It was observed a higher concentration of mineral impurities in smaller particles (< 0.250mm). The HHV varied from 15.9 to 18.3 MJ.kg-1 and showed no statistical difference for the treatments. The results indicate that the sugarcane trash presents problems related to mineral impurities which constrain its use as a solid fuel in the industry. The particle size interferes in their physicochemical characteristics. The trash can be stored in field and the time storage did not affect the quality for use as solid biofuel.
No manejo da cana-de-açúcar era comum a utilização do fogo para facilitar o corte e colheita da cana. No entanto, a Lei 11.241/02 do estado de São Paulo prevê a eliminação gradual da queima da palha da cana-de-açúcar. O maior produtor de cana-de-açúcar do Brasil é o estado de São Paulo, que possui aproximadamente 4,7 milhões de hectares de área plantada. É estimado que 1 hectare produza cerca de 14 toneladas de palha. Logo, as usinas vêm tentando incorporar esta palha na queima para geração de energia, juntamente com o bagaço. Porém, as altas concentrações de impurezas minerais estão impossibilitando seu uso para fins energéticos. O trabalho teve como objetivo o estudo da influência do tempo de estocagem e da granulometria na caracterização físico-química do palhiço da cana-de-açúcar. Foi utilizado o palhiço de canade-açúcar da superfície e do interior do fardo coletados em diferentes períodos de estocagem, 0, 1 e 2 anos. O material coletado foi separado em 4 granulometrias diferentes (> 0,420mm, 0,250-0,420mm, < 0,250mm e mix). As análises realizadas foram a distribuição granulométrica, a análise imediata, o poder calorífico superior (PCS), a análise química dos componentes das cinzas, as imagens no Microscópio Eletrônico de Varredura (MEV), o teor de lignina Klason, a holocelulose e os extrativos. Houve variações nos resultados do teor de cinzas com as diferentes granulometrias. Observou-se maior concentração de impurezas minerais nas partículas mais finas (< 0,250mm). O PCS variou entre 15,9 a 18,3 MJ.kg-1 e não apresentou diferença estatística para os tratamentos. Os resultados indicam que a palha de cana-de-açúcar apresenta problemas relacionados às impurezas minerais, que dificultam e restringem seu uso como combustível sólido na indústria. A granulometria da palha interferiu nas suas características físico-químicas. O palhiço pode ser estocado no campo e o tempo de estocagem não interferiu na qualidade para o uso como combustível sólido.
41
Bowen, James M. "Physicochemical characterization of discrete weapons grade plutonium metal particles originating from the 1960 BOMARC incident." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384850163.
Full text
42
Genco, Taha [Verfasser], Thomas [Akademischer Betreuer] Heinze, and Lidija Fras [Akademischer Betreuer] Zemljic. "Amino cellulose sulfate : synthesis, characterization and physicochemical behavior / Taha Genco. Gutachter: Thomas Heinze ; Lidija Fras Zemljic." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2013. http://d-nb.info/1038412390/34.
Full text
43
Fütterer, Sören [Verfasser]. "Nanoparticular iron complex drugs for parenteral administration - physicochemical characterization, biological distribution and pharmacological safety / Sören Fütterer." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1054682879/34.
Full text
44
Dawson, Jin Zhou. "Physicochemical characterization of PEG-based comb-like amphiphilic copolymer structures for possible imaging and therapeutic applications." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45921.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2008.Includes bibliographical references (p. 225-267).
Comb-like copolymer structures, also known as graft/comb copolymers, have obtained a significant amount of attention in biomedical and industrial applications because of their unique compositional flexibility, which can lead to versatile structures in bulk, melt, and solution states. With biomedical applications (cancer diagnosis and treatment) as the context, this thesis is aimed at characterizing a series of polyethylene glycol (PEG) -based highly adaptable amphiphilic comb copolymer structures in their solution state that can serve as carriers and potentially contrast enhancement agent in magnetic resonance imaging (MRI). To successfully develop and implement such a delivery/contrast agent system, an adequate understanding is needed concerning their physicochemical properties: stability, size, morphology, local structural information, and magnetic resonance characteristics. The stability of these copolymer structures was characterized by their critical micelle concentration (the lower this concentration, the higher the stability), which was determined by total intensity light scattering and surface tension measurement. The size, morphology, and detailed structural information were studied by a combination of techniques, i.e., dynamic light scattering, transmission electron microscopy, cryogenic transmission electron microscopy, and small angle neutron scattering. Furthermore, solutions of polymer structure containing perfluorocarbon blocks were characterized by 19F magnetic resonance spectroscopy to evaluate their application for MRI contrast enhancement. Perfluorocarbon-containing comb copolymers (i.e., PEG-PFC) in solution had a low CMC of about 2 [mu]m. They were found to form two populations of particles - small micelles and large secondary aggregates. Hydrodynamic radius of micelles did not change with polymer concentration, PEG length, sample preparation method, or time after sample preparation. Large secondary aggregates were most likely compound micelles. Sample preparation method, polymer molecular weight, and time after sample preparation could change the proportion of micelles vs. aggregates.
(cont.) Due to its "perfluoroalkyl-philic" property, PEG-PFC copolymer was able to encapsulate a perfluorocarbon compound, 1H, 1H, 2H, 2H-Perfluoro-l-decanol. 19F-NMR spectroscopy of PEG-PFC polymer solution showed significant spectral line broadening and consequent signal to noise (SNR) decrease due to micelle formation. Furthermore, hydrocarboncontaining comb copolymers (i.e., PEG-HyC) in PBS had a CMC of about 12 [mu]M. The micelles formed by PEG-HyC copolymer had an Rh of about 4-5 nm that did not change with polymer concentration. Because of the formation of nano-size micelles, both PEG-PFC and PEG-HyC copolymers are good candidates to be developed as delivery vehicles for imaging and therapeutic agents. Their low CMC is an indication of their potential ability to maintain micelle integrity in situations of massive dilution. PEG-PFC copolymers could also be used to encapsulate insoluble fluorinated drugs. Though micelle formation of PEG-PFC copolymer caused significant 19F-NMR spectral line broadening and consequent SNR reduction, the copolymer can be modified to act as smart 19F-MRI probes for cancer diagnosis.
by Jin Zhou Dawson.
Ph.D.
45
Laffey, Brian David. "Monoclonal antibodies to bovine serum albumin : affinity purification and physicochemical characterization dc by Brian David Laffey." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/32640.
Full text
46
Fisher, Erica L. "Physicochemical Characterization of a Novel Strawberry Confection for Delivery of Fruit Bioactives to Human Oral Mucosa." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316471870.
Full text
47
Mandal, Bivash. "Preparation and Physicochemical Characterization of Eudragit® RL100 Nanosuspension with potential for Ocular Delivery of Sulfacetamide." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271430956.
Full text
48
Looney, Melissa Ann. "Characterization of changes in composition and physicochemical properties of casein micelles from raw milk to buttermilk." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1162.
Full textAbstract:
It is well-documented that buttermilk has poor coagulation properties due to changes that occur to the casein micelles during the butter-making process. These modifications are generally attributed to the pasteurization of the cream upon which interactions between the proteins are promoted. It was hypothesized that churning is also a critical step for the changes that occur in composition of the casein micelles. The objective of this work was to learn more about the interactions that occur between casein micelles and MFGM components during the butter making process.
Raw cream was processed using a rotary churn at 18°C for approximately 30 minutes, and buttermilk was collected for analysis. Raw milk was skimmed at 10°C by centrifuging at 3000 x g for 20 minutes. Cream, skim milk and buttermilk were centrifuged at 60,000 x g for 40 minutes twice using imidazole buffer at pH 6.8 in order to isolate the micellar content in the pellet. Variation in physical properties of the casein micelles was determined using a Malvern Zetasizer. Protein profiles of UP cream, skim milk, and buttermilk were analyzed using one and two-dimensional gel electrophoresis technique. Experiments were performed using three different batches of UP cream, skim milk and buttermilk. Statistical analyses showed that processing the buttermilk significantly increased the surface charge (P0.05). Our results also indicate that churning of cream promoted interactions between casein micelles and MFGM proteins as shown by the more complex 2D-gel electrophoresis pattern obtained for casein micelles sedimented from buttermilk. This work is significant in its focus of better understanding the functionality changes of valuable milk components during the churning of cream.
49
Faria, Robersio Marinho de. "Estudo da dispersão das propriedades físico-químicas em blocos de alumina marrom obtida por eletrofusão." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/97/97134/tde-29032017-091850/.
Full textAbstract:
Tendo em vista a natureza finita dos minerais naturais, torna-se evidente a necessidade de utilizarmos este recurso de maneira estratégica. Desta forma, diversas pesquisas vêm sendo desenvolvidas principalmente nas áreas químicas, metalúrgicas e mineralógicas desde as etapas de extração, beneficiamento, aplicação e reutilização dos resíduos de minérios. Portanto, é extremamente importante a intensificação dos estudos para aumentar o conhecimento quanto às características e propriedades físico-químicas destes minerais, visando melhorar o seu aproveitamento e longevidade das jazidas naturais, como as fontes de bauxita, que é a principal matéria-prima para a produção de óxido de alumínio fundido. Na sua forma cristalina mais comum, denominada coríndon, ou óxido de alumínio ?, sua baixa condutividade elétrica, baixo calor específico, alta condutividade térmica, alto ponto de fusão, elevada dureza e resistência mecânica, o torna adequado para uso em produtos refratários, cerâmicos e abrasivos tais como, lixas, rebolos, ferramentas de corte e de polimento. Na síntese deste produto as principais impurezas que afetam a qualidade dos grãos são Fe, Si, Ca, K, Na e Zr, oriundas da matéria prima bauxita e da carta de mistura, composta por ilmenita, limalha de ferro, carvão vegetal e coque de petróleo. Desta forma, o presente trabalho assumiu o objetivo de estudar a dispersão das propriedades físico-químicas em blocos de alumina fundida marrom obtida em fornos Higgins a arco por eletrofusão, produzidos na Saint-Gobain Abrasivos, unidade de Lorena, SP. Por fim, foram utilizadas técnicas de caracterização físico-químicas de difratometria de raios X (DRX), análises químicas de fluorescência de raios X (FRX), ensaio de dureza Knoop e caracterização microestrutural via (MEV/EDS). Desta forma, foi definido o mapeamento composicional nos blocos de alumina eletrofundida marrom, que servirão como referência técnico-científica para subsidiar ações de melhoria deste produto, em decorrência do avanço do estado da arte deste referido assunto.The mineral ores are not renewable sources and we need to use it in the best way possible. In this way, a large number of researches are being developed around the world aiming the improvement of current methods of production mainly in chemical, metallurgy, mineralogical from the steps of extraction, processing, application and reuse of waste ore. Therefore, it is extremely important to intensify the studies to increase the knowledge about the characteristics and physicochemical properties of these minerals, in order to improve their utilization and longevity of natural deposits, such as sources of bauxite, which is the main raw material to product aluminum oxide fused. In its most common crystalline form, called corundum or ?-aluminum oxide, its low electrical conductivity, low specific heat, high thermal conductivity, high melting point, high hardness and mechanical strength, making it suitable for use as refractories, ceramics and fine or coarse abrasives. The synthesis of this product major impurities that affect quality of grain is Fe, Si, Ca, K, Na and Zr, derived from the raw material bauxite and the mixture chart consisting of ilmenite, iron filings, charcoal and coke oil. Thus, this shows the dispersion of physicochemical properties of brown fused alumina blocks produced by eletrocfusion at Higgins furnace process in the company Saint Gobain Abrasivos, Lorena- SP. Finally, the samples were physicochemical analyzed by X ray diffraction (XRD), chemical analyses by X ray fluorescence (XRF), hardnes using Knoop method, microstructural characterization by (SEM). The results of this work show a compositional gradient map of the fused alumina block; that shows the main physicochemical differences into the block, to support changes in the alumina production process; and it is also important to improve the actual state of art of this particular theme.
50
Rodrigues, Neibecker Leticia [Verfasser], and Gerhard [Akademischer Betreuer] Winter. "Development of novel vaccine carriers : physicochemical and biological characterization of hexosomes / Leticia Rodrigues Neibecker ; Betreuer: Gerhard Winter." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1178323722/34.
Full text