• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 55
  • 13
  • 9
  • 8
  • 7
  • 5
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 126
  • 16
  • 13
  • 12
  • 11
  • 11
  • 11
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Synthesis and Characterization of Mesoporous PMMA/POSS Particles

Miles, Craig January 2011 (has links)
No description available.
92

Bromodomain and Extraterminal Domain (BET) Inhibitor RVX-208 Ameliorates Periodontal Bone Loss

Clayton, Nicholas J 01 January 2018 (has links)
Periodontal disease affects 47% of Americans over 30 and is a growing global concern. Current treatments for periodontal disease focus on the mechanical elimination of periodontal biofilms. Very few treatments are available that target the rampant, unregulated host immune response that is ultimately responsible for tissue degradation. BET proteins have been shown to play critical roles in inflammatory gene regulation and are therefore potentially ideal therapeutic targets for treating periodontal disease. RVX-208 is a selective BET-inhibitor with a high affinity for Bromodomain 2 (BD2) as compared to BD1 in BET proteins. Our previous studies have shown that RVX-208 inhibits inflammatory cytokine production and suppresses osteoclast differentiation. Cell culture assays have provided proof of concept for RVX-208 and its feasibility as a treatment for periodontal disease. As such, our long term goal is to develop RVX-208 as a front-line treatment for periodontitis. The objectives of this study were to determine the ability of RVX-208 to reduce bone loss in a ligature-induced periodontitis model, and to further investigate the mechanisms through which RVX-208 mediates its anti-inflammatory and osteoclastogenesis-suppressive effects. The specific aims of this study were: 1) To further validate the in vivo effects of RVX-208 on a ligature-induced periodontitis model in rats, and 2) To determine the molecular mechanisms of RVX-208 on preventing alveolar bone loss in periodontal disease. To investigate, a ligature-induced periodontitis model was created in rodents. Those rodents were treated with increasing dosages of RVX-208 (0-2.5 mM) by subgingival injection every other day. After 2 weeks, the maxillae were harvested and analyzed via a micro-CT protocol that had been created and validated through statistical analyses. To study the ability of RVX-208 to suppress osteoclastogenesis, RAW264.7 cells were induced into osteoclasts by RANKL and then treated with RVX-208. To ensure RVX-208 was not species specific, THP-1 cells were challenged with either E. coli-LPS or P. gingivalis bacteria and then treated with RVX-208. Linear and volumetric micro-CT analysis showed that RVX-208 could significantly ameliorate bone loss in a ligature-induced periodontitis model. RVX-208 was shown to prevent osteoclast differentiation by suppressing the expression of genes closely associated with osteoclast differentiation and maturation. RVX-208 was found to not be species specific, as it was able to mediate its effects on a human cell line, and had consistent anti-inflammatory effects regardless of whole pathogen or LPS-induced inflammatory response. Therefore, RVX-208 is a promising therapeutic for treatment of periodontal diseases.
93

Carbon Nanotube Based Electrochemical Supercapacitors

Zhou, Chongfu 31 July 2006 (has links)
Several approaches have been used to develop carbon nanotube (CNT) based electrochemical supercapacitors. These approaches include the following: (a) stabilization and carbonization of ternary composites of polyacrylonitrile (PAN), poly (styrene co-acrylonitrile) (SAN) copolymer, and single wall carbon nanotubes (SWNTs); (b) SWNT membranes functionalized with aryl chloride, sodium sulfonate, aryl sulfonic acid, bis(3,5-di-tert-butylphenyl)5-aminobenzene-1,3-dioate, and 4,4 -methylenedianiline; and (c) pyrrole treated SWNTs. In addition nitric acid functionalized and heat-treated SWNT membranes have been studied. The electrochemical supercapacitor behavior of these membrane electrodes has been characterized by cyclic voltammetry, constant current charging-discharging, and impedance analysis in aqueous and ionic liquid electrolytes. Long term performance of selected electrodes has been evaluated. The surface area and pore size distribution was quantified by N2 gas adsorption/desorption and correlated with capacitance performance. The surface functional groups have been characterized by X-ray photoelectron spectroscopy. CNT electrode/electrolyte interaction has been characterized using contact angle measurements. Electrolyte absorption by the electrodes has also been characterized. Carbonized PAN/SAN/SWNT ternary composites exhibit double layer capacity of over 200 μF/cm2. By comparison, the double layer capacity of classical meso-porous carbons is in the range of 10-50 μF/cm2. The capacitance of functionalized SWNTs is up to 2 times that of the control bucky paper made from unfunctionalized SWNTs. Energy density of functionalized electrodes when evaluated in an ionic liquid is as high as 28 kJ/kg. High capacitance (up to 350 F/g) was obtained for pyrrole-treated functionalized SWNT membranes in 6 M KOH. This value is almost seven times that of the control bucky paper. Correlating the capacitance with surface area and pore size distribution, it was observed that macropores (pore width greater than 50 nm) play an important role for achieving high capacitance.
94

Quantitative evolutionary analysis of the life cycle of social amoebae

Dubravcic, Darja 15 November 2013 (has links) (PDF)
Social amoebae are eukaryotic organisms that inhabit soil of almost every climate zone. They are remarkable for their switch from unicellularity to multicellularity as an adaptation to starvation. When starved, millions of single cells aggregate and form a multicellular fruiting body, which contains reproductive spore cells and dead stalk cells, which help in spore dispersion. This costly behavior made social amoebae a model system for addressing major questions of the evolution of cooperation and multicellularity. In this study we look at three different aspects of social amoebae behavior; aggregation, non-aggregation and competition, and ask how they contribute to our understanding of cooperation in social amoebae and microbial systems in general.We explored the known but neglected observation that, upon starvation, not all cells aggregate and engage in multicellular development. We describe phenotypically and genetically non-aggregating cell proportion in D. discoideum species. Both aggregating and non-aggregating strategy are costly or beneficial depending on duration of starvation. With our computational model we propose that partitioning the population into unicellular and multicellular states is adaptive in fluctuating environments with unpredicted duration of starvation periods. Social amoebae may therefore lie at the intersection of cooperation and bet-hedging. In the second part, we provide a new framework for addressing the contrasting observations of high genetic diversity in natural populations of social amoebae and experimentally suggested low diversity-high relatedness required for cooperation. We propose that complex life cycle of social amoebae provides multiple competition points that can possibly play an important role in maintaining diversity and cooperation. We explore this experimentally and computationally by looking at competition over the whole life cycle between 6 natural isolates of D. discoideum. Our simulation model indicates that competition at different stages of the life cycle can lead to exclusion of "social winners". Though we failed to explain strain coexistence. Although preliminary, our results emphasize the importance of integrating species ecology in cooperative studies.Finally, we focus on a new aggregation dynamics in P. pallidum species observed in our lab. Aggregation is a population level process during which population gets divided into numerous subpopulations/aggregates that face selection independently. Such population partitioning can have strong evolutionary consequences on cooperation that have not yet been explored experimentally. We describe the population dynamics qualitatively and propose several quantitative measurements of population partitioning into aggregates. Our preliminary results suggest that there is a preference for aggregates of certain size, but there is no spatial organization of aggregates.
95

Erdvės ir laiko konceptai Deleuze'o kino filosofijoje / Space and time concepts in Deleuze's philosophy of cinema

Akelytė, Simona 31 July 2012 (has links)
Gilles Deleuze'as kuria kinui būdingus konceptus, kurie pagilina kino problematiką, suteikdami jai filosofinį pagrindą. Savo vaizdinio-judėjimo ir vaizdinio-laiko knygose – Kinas 1 ir Kinas 2 – Deleuze'as konceptus taiko klasikiniui ir moderniajam kinui. Kino filmų jis nepasirenka kaip savo konceptų iliustracijų, o juos vertina kaip tuos pačius konceptus, išreikštus vaizdine forma. Pagrindinis šio magistrinio darbo tikslas – aptarti bet-kurios-erdvės, kuri priklauso vaizdinio-judėjimo kinui ir išreiškia netiesioginį laiką, ir vaizdo-kristalo, išreikšiantį sudėtingą tiesioginio laiko sistemą, konceptus ir tirti jų apraiškas kino mene. / Gilles Deleuze creates concepts characteristic of cinema which deepen the problematics of cinema providing a philosophical basis to it. In his books of movement-image and time-image – Cinema 1 and Cinema 2 – Deleuze applies concepts to classical and modern cinema. He doesn‘t choose movies as illustrations of his concepts but values them as the same concepts expressed in visual form. The main aim of this master thesis – to discuss the concepts of any-space-whatever, which belongs to the cinema of movement-image and expresses indirect time, as well as of crystal-image, which expresses a complex system of direct time, and to investigate their manifestations in the art of cinema.
96

Vapour-liquid equilibria within nanoporous media

Brown, Jacob Leslie January 2018 (has links)
This thesis is dedicated to the exploration of fluid phases confined in nanoporous materials using Nuclear Magnetic Resonance (NMR) techniques, with an aim to benefit catalysis research. Included in this report are studies of pure fluids and their mixtures, confined in titania and silica catalyst supports. These investigations are conducted at industrially-relevant, high-temperature (≥ 180 °C) and high-pressure conditions (up to 13 bar), made possible by a pilot-scale chemical reactor unit, designed to operate inside the strong magnetic fields of an NMR spectrometer. NMR spectroscopy, relaxation and pulsed field gradient (PFG) diffusion experiments were performed on each of the systems discussed in this report. Cyclohexane was initially studied inside a porous titania catalyst support at 188 °C and various pressures up to 13 bar. The adsorption and desorption processes of the cyclohexane were observed, revealing a number of previously unobserved phenomena. In addition to an overall, averaged diffusion coefficient, a slow diffusion coefficient was observed within the PFG NMR data attributable to surface diffusive processes occurring within the material. Additionally, T1 relaxation studies were found to provide experimental evidence for the differing configurations of adsorbed layers on the adsorption and desorption branch of the isotherm. Cyclohexane was subsequently studied alongside fluorobenzene in a series of silica catalyst supports of 6 nm, 10 nm and 20 nm pore size. In doing this, it was hoped that the multiple phenomena observed in the titania experiments might be deconvoluted, allowing a greater level of insight. The diffusivities of the fluids were found to differ significantly between the materials, and greater evidence was found of the slow-diffusing surface phase in each of the materials. Additionally, concentrations of cyclohexane and fluorobenzene in the gas and adsorbed layers inside the pore space were calculated via the results of the PFG NMR experiments, providing a map of confined phase behaviour. Competitive adsorption effects were found to become more significant, the smaller the pore size of the material. The results of the cyclohexane and fluorobenzene in silica studies were modelled, using approaches available in the literature, which were found to give varying levels of prediction. The data set acquired in this thesis was found to provide a useful standard, against which current and future models of confined phase behaviour might be verified.
97

Kurzové sázky jako jedna z forem patologického hráčství u adolescentů / Odds betting as a form of pathologic gambling among adolescents

DOKULIL, Ondřej January 2016 (has links)
The diploma thesis focuses on fixed-odds betting among male adolescents. In theoretical part, game as a whole life matter is explained, afterwards it aims closer to hazard game, especially fixed-odds betting. Regarding to children, multiple smaller studies, focused on risky behaviour on the internet and gambling, are introduced. Empirical part combines qualitative and quantitative approach. Interviews with betters jointly with the theory creates the base for hypothesises and questionnaire, which was distributed in five schools; three elementary and two high schools. Results of the empirical part are suggesting that adolescent boys have experiences with fixed-odds betting even though they are not of age. Frequently, the reason for betting is being involved in sport and the favourite form is on-line betting.
98

Qual índice de mercado utilizar?: um teste das aproximações da Carteira de Mercado Brasileira

Volpe, Brunno Muhringer 20 May 2010 (has links)
Submitted by Roberta Lorenzon (roberta.lorenzon@fgv.br) on 2011-05-27T13:47:34Z No. of bitstreams: 1 63080100004.pdf: 368251 bytes, checksum: ce0bde671225071c3084007fcda47ca1 (MD5) / Approved for entry into archive by Suzinei Teles Garcia Garcia(suzinei.garcia@fgv.br) on 2011-05-27T14:10:52Z (GMT) No. of bitstreams: 1 63080100004.pdf: 368251 bytes, checksum: ce0bde671225071c3084007fcda47ca1 (MD5) / Approved for entry into archive by Suzinei Teles Garcia Garcia(suzinei.garcia@fgv.br) on 2011-05-27T14:11:59Z (GMT) No. of bitstreams: 1 63080100004.pdf: 368251 bytes, checksum: ce0bde671225071c3084007fcda47ca1 (MD5) / Made available in DSpace on 2011-05-27T15:16:43Z (GMT). No. of bitstreams: 1 63080100004.pdf: 368251 bytes, checksum: ce0bde671225071c3084007fcda47ca1 (MD5) Previous issue date: 2010-05-20 / Este trabalho analisa as propriedades de alguns índices em busca da melhor aproximação (proxy) para a carteira de mercado brasileira. Além dos usuais Ibovespa, IBrX, FGV-100, são considerados dois índices construídos segundo as diretrizes da Moderna Teoria de Carteiras, a saber, uma carteira ponderada pelo valor de mercado (PV) e uma carteira igualmente ponderada (PI). Em um primeiro teste é analisada a eficiência em média e variância e em um segundo avalia-se o potencial dos índices como fatores de risco sistemático. O estudo cobre o período de 1996 a 2009 e todas as ações negociadas na BOVESPA. Os resultados evidenciam a semelhança nas qualidades dos índices, não sendo possível destacar uma melhor aproximação. Ibovespa, IBrX e FGV-100 são aproximações razoáveis e podem ser utilizadas.
99

Characterization of Cu-Co-Cr-K Catalysts

Doan, Phuong Thanh 04 August 2001 (has links)
The production of higher alcohols from synthesis gas over Cu-Co-Cr-K catalysts has been studied. The production rate of alcohol was measured in the flow reactor, operating at 250 to 350°C, 3500 to 8000 gas hourly space velocity, and 900 to 1800 psig. The productivity as a function of temperature, pressure, gas hourly space velocity, carbon dioxide content of the feed, and reaction time was also examined. Physisorption data have been analyzed using the Langmuir model, the Brunauer-Emmett-Teller (BET) method, the Barret-Joyner-Halenda (BJH) method, and the de Boer and Halsey t-method. The surface areas of catalysts CB1(1), CB1(3), and CB1(1) after reaction were 39.9 ± .9 m2/g, 28.9 ± 1.7 m2/g, and 26.5 ± 0.3 m2/g, respectively. Moreover, information such as pore size distribution, pore shape, monolayer volume, micropore volume and thickness of adsorption layer were also obtained. The atomic concentration and oxidation states of near surface species were established by X-ray Photoelectron Spectroscopy.
100

Integrated Study of Rare Earth Drawdown by Electrolysis for Molten Salt Recycle

Wu, Evan January 2017 (has links)
No description available.

Page generated in 0.0671 seconds