A new class of polymer coated lanthanide fluoride nanoparticle aggregates (NPAs) was developed as potential MRI contrast agents. The NPA synthesis has been perfected to control the size distribution and optimize relaxivities. Polyacrylic acid was used as a stabilizing polymer, and was conjugated to folic acid to improve targeting to SK-BR-3 breast cancer cells. Terbium was incorporated in the synthesis to study the passive and active targeting properties of NPAs. Through a series of microscopy experiments, a significant difference in uptake between NPAs with and without targeting moieties occurs after 48 hours of incubation. The relaxivity of the optimized nanoparticles was measured to be 56 s-1(mg/ml)-1 using a 1.5 T scanner, which may be compared to that of the commercially available Gd3+-DTPA [R1 = 7 s-1(mg/ml)-1]. Abdominal perfusion studies in rats also demonstrated that the NPAs provide better contrast of the vasculature than Gd3+-DTPA does at the same mass concentration.

Following Carslaw [1] and as discussed by Becker et al [2], the diffusion of ultrasonic energy in cement-based aggregates follow the heat diffusion equation. However, due to the finite size of the discs used in experiments by Becker, ultrasound energy is contained within the body for a longer period of time, as compared to [2]. Though the energy content of the disc in reality would eventually decay to zero, due to leaks and other mechanisms, a theoretical study of perfectly adiabatic case is useful to compare the residual energy values to material properties. As a particular example, the input energy sees multiple phenomena inside the material during propagation. The residual energy is this a combined effect of the multiple scattering, dissipative and diffusive processes. This objective of this thesis is to study the relationship between the residual spectral density and specimen geometry. The effort further aims to attribute the difference in the residual spectral energy density values in materials of similar geometry to the varying material properties of the heterogeneous materials. Finally, a study of the error propagation in the estimation is presented, along-with an analytical relationship showing the value of spectral energy density for discs of finite radius and height. Ref: 1. H. S. Carslaw, J.C.J., Conduction of Heat in Solids. 2nd ed ed. 1986: Oxford University Press, USA. 520 2. Becker, J., L.J. Jacobs, and J. Qu, Characterization of cement-based materials using diffuse ultrasound. Journal of Engineering Mechanics, 2003. 129(12): p. 1478-1484.

Testing of asphalt binders and asphalt-aggregate mixtures using dynamic mechanical analysis is becoming popular with improvements in high-speed computers, precision equipment, and computer software. Researchers are trying to describe the behavior of asphalt binders and asphalt-aggregate mixtures in terms of their time- and temperature-dependent linear viscoelastic behavior. The objectives of this thesis were to develop a simplified pneumatic test to perform dynamic mechanical analysis (DMA), to evaluate the performance of the pneumatic and hydraulic test systems using the computer software developed to perform DMA tests, and, to develop a simplified method to evaluate the experimental data obtained from DMA tests on aged asphalt-aggregate mixtures. A simplified pneumatic test system was developed to perform DMA. Computer software was also developed to perform DMA testing on both the simplified pneumatic and hydraulic test systems. DMA was performed on both test systems to compare their performance, and on aged asphalt-aggregate mixtures to evaluate the application of the simplified method. The results from the pneumatic and hydraulic test systems show that there is about a 20 percent difference in the complex modulus, especially at high loading frequencies. This is due to the compressibility of the air used in the pneumatic test system. The compressibility of air is greater at warmer temperatures than at cooler temperatures. Therefore, the application of the pneumatic test system to perform dynamic testing should be limited to low frequencies ( < 2 Hz), low temperatures ( < 25°C), and low load ( < 454 kg (1000 lbs.)) applications unless a modification can be made to increase the pneumatic cylinder's response time to match the hydraulic cylinder's response time. The simplified analysis method developed in this thesis divides the DMA results into four complex modulus and five phase angle parameters. These parameters describe the shapes of the master stiffness and phase angle curves and distinguished between the different asphalt-aggregate mixtures and the aging methods performed on the aged asphalt-aggregate mixtures. The phase angle parameters were reduced into two variables, peak frequency and peak angle, which vary with the aging of each asphalt-aggregate mixture. The peak frequency and peak angle decrease as the aging severity increases and the change of peak frequency and peak angle vary with the asphalt-aggregate mixture and aging treatment. Therefore, the complex modulus parameters and peak frequency and peak angle may be good indicators to describe how a master curve's shape varies with asphalt, aggregate, and aging type. / Graduation date: 1993

Thesis (Ph.D.)--Tufts University, 2003. / Adviser: Daniel C. Jansen. Submitted to the Dept. of Civil Engineering. Includes bibliographical references (leaves 146-152). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (PhD) - Swinburne University of Technology, 2006. / Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil Engineering, Swinburne University of Technology - 2006. Typescript. Includes bibliographical references.

Thesis (M.S.) -- Mississippi State University. Department of Civil Engineering. / Title from title screen. Includes bibliographical references.

La sclérose Latérale Amyotrophique (SLA) est une maladie neurodégénérative des motoneurones impliquant des facteurs environnementaux et génétiques. Notre étude porte sur l’étude des relations entre la voie de la SUMOylation post-Traductionnelle des protéines et les effets du stress oxydant et de mutants SOD1. Nous montrons tout d’abord que 2 nouveaux mutants, SOD1V31A et SOD1E121G identifiés chez des patients SLA à évolution lente, entraîne la formation d’agrégats cellulaires Ub/SUMO dans la formation des agrégats était suggérée. Nous montrons 1) que les NSC-34 exposées à un stress oxydant et exprimant SOD1 mutée présentent une modification d’expression de plusieurs gènes des voies de l’Ub/SUMO ; 2) que l’expression de SOD1 mutée réduit le pool de protéine SUMO-1 libre dans les cellules motoneuronales, possible conséquence d’une séquestration dans les agrégats ; 3) qu’inhiber la SUMOylation de SOD1 mutée réduit la quantité de cellules avec agrégats. Nos résultats indiquent qu’une meilleure connaissance de la voie de SUMO pourrait conduire à de nouvelles cibles thérapeutiques intéressantes dans la SLA. / Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease of motor neurones involving a combination of environmental and genetics factors. Ours work focuses on the relathionship between the SUMOylation pathway and the effects of oxidative stress and SOD1 mutants. We first show that 2 new mutants, SOD1V31A and SOD1E121G identified in ALS patients with a slowly progressive disease, induce the formation of Ub/SUMO positive aggregates in motor neuronal cells NSC-34. The implication of the Ub/SUMO pathways has been proposed in the formation of aggregates in ALS. We show 1) modification of expression of several genes of the Ub/SUMO pathways in NSC-34 exposed to oxidative stress and expressing various mutated SOD1 proteins; 2) that the expression of mutants SOD1 reduces free-SUMO1 concentration in motor neuronal cell, perhaps by a sequestration in aggregates; 3) that the inhibition of SUMIylation of various mutants SOD1 reduces the amount of cells with aggregates. Our results support further studies on the SUMO pathway that may lead to new therapeutics targets in ALS.

The importance of studying the behaviour and properties of concrete can be highlighted by considering the fact that concrete is the most used man-made material in the world. The very first step in making concrete is its mix design and deciding the type and amount of constitutes used in the production of concrete which should fulfil the requirements of the final product. Mix design models are commonly used for the purpose of proportioning concrete ingredients while anticipating the properties of the final product.  The current document deals with the commonly used principals in mix design models namely particle packing theory and excess water/paste layer theories. The conducted studies includes an investigation on accuracy of particle packing models (Toufar, 4C, CPM) and also tries to address the issue with measurement of specific surface area of particles as an essential input to water/paste layer theories.  It has been observed that the particle packing models can predict the packing density with acceptable margin. However, it should be mentioned that the particle packing models by themselves are not mix design models but should be rather used as a part of a mix design. In addition, it was found that the accuracy of calculating the specific surface area of particles based on their size distribution curve can be further improved by assuming angular platonic solids as uniform shape of aggregate instead of traditional approach of assuming spheres for aggregates’ shape.

Esta dissertação teve como objetivo o desenvolvimento da técnica de síntese por combustão em solução para obtenção de nanocristais de espinélio MgAl2O4, e a caracterização desse material por diferentes técnicas. O estudo da obtenção incluiu o cálculo termodinâmico das reações envolvidas e a influência da razão combustível-oxidante no tamanho de cristalito. A síntese de espinélio MgAl2O4 por combustão foi realizada a partir do trio precursor químico sacarose, nitrato de alumínio e nitrato de magnésio em água, para diferentes razões combustível-oxidante, temperaturas de chama e número total de moles gasosos, relacionando esses parâmetros com tamanho de cristalito do pó, deformação de rede e área superficial. As reações químicas de combustão em solução resultaram na formação in situ de fases amorfas de MgAl2O4 para o pó como-sintetizado. A fase cristalina somente foi obtida após um tratamento térmico a 900°C do pó como-sintetizado. O cálculo termodinâmico da reação de combustão em solução mostrou que quando a razão combustível-oxidante aumenta, obtém-se uma elevação da temperatura de chama adiabática e da quantidade de gás produzida, definindo características do particulado como morfologia, tamanho de cristalito, área superficial e nível de agregação. Para a caracterização do pó utilizaram-se técnicas como análise termodiferencial (ATD) e termogravimétrica (ATG), granulometria por dispersão de laser (GDL), BET para análise de área superficial, análise cristalográfica por difração de raios X (DRX), microestrutura por microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (MET). Os pós de espinélio MgAl2O4 obtidos apresentaram-se como constituídos de cristalitos nanométricos, dispostos na forma de agregados de tamanho micrométrico. O tamanho de cristalito médio, calculado pelo método Single Line, a partir de dados de análises por DRX, foi de 21,57 nm, e deformação média calculada de 1,99 x 10-³ nm. Por análise granulométrica constatou-se um tamanho de aglomerado médio de 27,27 µm, com distribuição trimodal. As análises por MEV e MET confirmaram a agregação das partículas do pó sintetizado, a partir de partículas com morfologia irregular e do tamanho nanométrico dos cristalitos. / The goals of the dissertation were to investigate and develop the solution combustion synthesis technique in order to obtain nanocrystalline spinel MgAl2O4 powders and characterize them by different techniques. This study has also included thermodynamic calculation for reactions, which have been investigated and the influence of fuel-to-oxidant ratio on crystallite size. The combustion synthesis of MgAl2O4 spinel was performed by a trio of chemical precursor sucrose, aluminum nitrate and magnesium nitrate in water, for different fuel-to-oxidant ratios, flame temperatures and total mol number of gases, correlating these parameters with crystallite size, strain, surface area and total porosity. The chemical reactions of solution combustion resulted on amorphous phase formation of MgAl2O4 in situ for as-synthesized powder. The crystalline phase formation of spinel MgAl2O4 was only succeeded obtained after a thermal treatment of as-synthesized powder under 900°C. The thermodynamic calculation of the combustion reaction of the combustion reaction shows that as fuel-to-oxidant ratio increases the amount of gas produced and adiabatic flame temperature also increases. Powder characteristics as morphology, crystallite size, surface area and aggregation degree are mainly governed by the flame temperature and generation of gases. The techniques used for powder characterization included differential thermal analyzer (DTA), thermogravimetric analyzer (TGA), particles size analyzer (PSA), surface area by BET analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The spinel MgAl2O4 powders obtained were composed of nano-size crystallites, but in micrometer-sized aggregates. The mean particle size calculated, via Single Line method, using XRD was 21.57 nm and the mean strain calculated was 1.99 x 10-³ nm. PSA indicated that the synthesized powders contain a mean aggregates size with a tri mode distribution of around 27.27 µm. TEM and SEM analyses confirmed that the as-synthesized powders are composed of particles aggregation. They have an irregular morphology and nano-size crystallites.

Quantitative and qualitative Soil Organic Matter (SOM) properties were observed in the soil samples of a medium-term field experiment (Cambisol ? Studena, Czech Republic) and an exact field experi?ment (Chernozem ? Gross Enzersdorf, Austria) in the year 2005 considering different soil tillage systems (conventional and minimum tillage). Except the standard parameters, soil organic matter content and quality in particulate water stable aggregates size fractions was additional determinated for Cambisol. Cambisol showed more favourable values of both quantitative and qualitative SOM parameters in minimum tillage system compared to those in conventional tillage system. SOM quality in the water stable aggregates fractions was better in minimum tillage compared to conventional tillage. Cambisol also showed that SOM in aggregates fractions is much more quality compared to SOM in the original soil samples. Chernozem showed higher values of both quantitative and qualitative SOM parameters in conventional tillage compared to those in minimum tillage but the differences are not high. It can be said that Chernozem organic matter reaction to tillage technology changes is slower and of minor rate in comparison with that of Cambisol organic matter. The results of quantitative and qualitative parameters do not conform to the generally recognised values for the Chernozem soil type.