To study the effect of meat (beef) on dietary iron bioavailability from enriched white bread (EWB) or whole wheat bread (WWB), diets were prepared in which the ratios of beef iron to bread iron were 100:0, 75:25, 50:50, 25:75 or 0:100. Hemoglobin regeneration efficiency (HRE), apparent iron absorption, and dry matter absorption were determined using weanling anemic and healthy male rats. Meat iron was more available than EWB or WWB. Fortification iron in EWB was less available than the iron naturally present in WWB. At the iron dose given, HRE was similar for both anemic and healthy rats. Although healthy rats absorbed less dietary iron than the anemic ones, bread types did not affect percent iron absorbed. Iron status did not affect dry matter absorption from meat, bread or meat:bread mixtures. Meat did not enhance iron bioavailability from EWB or WWB diets. To study the iron bioavailability of meat loaf prepared from meat and whole wheat flour (WWF) or whole wheat bread (WWB), diets were formulated with 30 ppm iron as cooked meat, WWF, WWB, meat loaf with 67% of the iron from meat and 33% from flour (or bread), or meat loaf with 33% of the iron as meat and 67% from flour (or bread). HRE, apparent iron absorption, dry matter absorption, total body iron gain (iron retention), iron59 retention and absorption and heme iron absorption were determined using anemic and healthy male rats. HRE•s for healthy rats were similar for both meat:flour or meat:bread loaves. Anemic rats absorbed more iron than healthy rats. Baking increased slightly the percent iron absorbed by anemic rats. Iron status did not affect dry matter absorption from t he diets. The total iron bioavailability of the whole wheat flour or bread diets was not enhanced by dietary meat. Anemic rats retained and absorbed more iron59 than healthy rats and this difference increased with the ratio of iron from flour or bread in the meat loaves. The absorption of iron 59 (nonheme iron) was influenced by source of iron in the diet (meat, flour, bread or FeS04) and also nutritional status (anemic or healthy rats). Healthy rats had almost one-half the specific activity in their bodies and hemoglobin iron as the anemic ones had. Baking the flour into bread did not affect the specific activity of liver, body or hemoglobin iron. It was concluded that meat did not enhance nonheme iron absorption in this study. Heme iron absorption, determined by indirect means, was about 50% of the total heme iron in the diets for both anemic and healthy rats.

Indiana University-Purdue University Indianapolis (IUPUI) / Modern DNA profiling techniques have increased in sensitivity allowing for higher success in producing a DNA profile from limited evidence sources. However, this can lead to the amplification of more DNA profiles that do not get a hit on a suspect or DNA database and more mixture profiles. The work here aims to address or improve these consequences of current DNA profiling techniques. Based on allele-specific PCR and quantitative color measurements, a 24-SNP forensic phenotypic profile (FPP) assay was designed to simultaneously predict eye color, hair color, skin color, and ancestry, with the potential for age marker incorporation. Bayesian Networks (BNs) were built for model predictions based on a U.S sample population of 200 individuals. For discrete pigmentation traits using an ancestry influenced pigmentation prediction model, AUC values were greater than 0.65 for the eye, hair, and skin color categories considered. For ancestry using an all SNPs prediction model, AUC values were greater than 0.88 for the 5 continental ancestry categories considered. Quantitative pigmentation models were also built with prediction output as RGB values; the average amount of error was approximately 7% for eye color, 12% for hair color, and 8% for skin color. A novel sequencing method, methyl-RADseq, was developed to aid in the discovery of candidate age-informative CpG sites to incorporate into the FPP assay. There were 491 candidate CpG sites found that either increased or decreased with age in three forensically relevant xii fluids with greater than 70% correlation: blood, semen, and saliva. The effects of exogenous microbial DNA on human DNA profiles were analyzed by spiking human DNA with differing amounts of microbial DNA using the Promega PowerPlex® 16 HS kit. Although there were no significant effects to human DNA quantitation, two microbial species, B. subtilis and M. smegmatis, amplified an allelic artifact that mimics a true allele (‘5’) at the TPOX locus in all samples tested, interfering with the interpretation of the human profile. Lastly, the number of contributors of theoretically generated 2-, 3-, 4-, 5-, and 6-person mixtures were evaluated via allele counting with the Promega PowerPlex® Fusion 6C system, an amplification kit with the newly expanded core STR loci. Maximum allele count in the number of contributors for 2- and 3-person mixtures was correct in 99.99% of mixtures. It was less accurate in the 4-, 5-, and 6-person mixtures at approximately 90%, 57%, and 8%, respectively. This work provides guidance in addressing some of the limitations of current DNA technologies.

Multivariate Gaussians: We provide sample complexity upper bounds for semi-agnostically learning multivariate Gaussians under the constraint of approximate differential privacy. These are the first  finite sample upper bounds for general Gaussians which do not impose restrictions on the parameters of the distribution. Our bounds are near-optimal in the case when the covariance is known to be the identity, and conjectured to be near-optimal in the general case. From a technical standpoint, we provide analytic tools for arguing the existence of global "locally small" covers from local covers of the space. These are exploited using modifications of recent techniques for for differentially private hypothesis selection. Mixtures of Gaussians: We consider the problem of learning mixtures of Gaussians under the constraint of approximate differential privacy. We provide the first sample complexity upper bounds for privately learning mixtures of unbounded axis-aligned (or even unbounded univariate) Gaussians. To prove our results, we design a new technique for privately learning mixture distributions. A class of distributions F is said to be list-decodable if there is an algorithm that, given "heavily corrupted" samples from a distribution f in F, outputs a list of distributions, H, such that one of the distributions in H approximates f. We show that if F is privately list-decodable then we can privately learn mixtures of distributions in F. Finally, we show axis-aligned Gaussian distributions are privately list-decodable, thereby proving mixtures of such distributions are privately learnable. / Thesis / Master of Science (MSc) / Is it possible to estimate an unknown probability distribution given random samples from it? This is a fundamental problem known as distribution learning (or density estimation) that has been studied by statisticians for decades, and in recent years has become a topic of interest for computer scientists. While distribution learning is a mature and well understood problem, in many cases the samples (or data) we observe may consist of sensitive information belonging to individuals and well-known solutions may inadvertently result in the leakage of private information. In this thesis we study distribution learning under the assumption that the data is generated from high-dimensional Gaussians (or their mixtures) with the aim of understanding how many samples an algorithm needs before it can guarantee a good estimate. Furthermore, to protect against leakage of private information, we consider approaches that satisfy differential privacy — the gold standard for modern private data analysis.

<p>This thesis is concerned with the problem of characterizing the orbits of certain probability density functions under the action of the Euclidean group. Our motivating application is the recognition of a point configuration where the coordinates of the points are measured under noisy conditions. Consider a random variable X in R^d with probability density function ρ(x). Let x₁ and x₂ be independent random samples following ρ(x). Define ∆ as the squared Euclidean distance between x₁ and x₂. It has previously been shown that two distributions ρ(x) and ρ(x) consisting of Dirac delta distributions in generic positions that have the same respective distributions of ∆ are necessarily related by a rigid motion. That is, there exists some rigid motion g in the Euclidean group E(d) such that ρ(x) = ρ(g · x) for all x ∈ R^d . To account for noise in the measurements, we assume X is a random variable in R^d whose density is a k-component mixture of Gaussian distributions with means in generic position. We further assume that the covariance matrices of the Gaussian components are equal and of the form Σ = σ²1_d with  0 ≤ σ² ∈ R. In Theorem 3.1.1 and Theorem 3.2.1, we prove that, when σ² is known, generic k-component Gaussian mixtures are uniquely reconstructible up to a rigid motion from the density of ∆. A more general formulation is proven in Theorem 3.2.3. Similarly, when σ² is unknown, we prove in Theorem 4.1.1 and Theorem 4.1.2 that generic equally-weighted k-component Gaussian mixtures with k = 1 and k = 2 are uniquely reconstructible up to a rigid motion from the distribution of ∆. There are at most three non-equivalent equally weighted 3-component Gaussian mixtures up to a rigid motion having the same distribution of ∆, as proven in Theorem 4.1.3. In Theorem 4.1.4, we present a test to check if, for a given k and d, the number of non-equivalent equally-weighted k-component Gaussian mixtures in R^d having the same distribution of ∆ is at most (k choose 2) + 1. Numerical computations showed that distributions with k = 4, 5, 6, 7 such that d ≤ k −2 and (k, d) = (8, 1) pass the test, and thus have a finite number of reconstructions up to a rigid motion. When σ² is unknown and the mixture weights are also unknown, we prove in Theorem 4.2.1 that there are at most four non-equivalent 2-component Gaussian mixtures up to a rigid motion having the same distribution of ∆. </p>

Bone is a dynamic tissue, where bone forming osteoblasts and bone resorbing osteoclasts maintain homeostasis. Research into bone toxicology has largely focused on pharmaceutical side effects adversely affecting bone development. However, many environmental toxicants can regulate bone homeostasis. Recently, the nuclear receptor peroxisome proliferator activated receptor gamma (PPARγ) has emerged as an important target of environmental toxicants. PPARγ dimerizes with the retinoid-X receptor alpha (RXRα), is a central transcription factor in adipogenesis, and in bone can transdifferentiate osteoblasts into adipocytes by suppressing osteogenic pathways. The central hypothesis of this dissertation is that environmental chemicals can adversely affect bone homeostasis by activating nuclear receptors in bone cells – particularly osteoblasts and osteoclasts – to perturb cellular differentiation and function. Three study aims were developed to test and refine this hypothesis. First, a set of structurally diverse environmental PPARγ agonists were individually applied to mouse primary bone marrow mesenchymal stromal cell cultures undergoing osteogenic differentiation. In vitro PPARγ ligand treatment suppressed osteogenesis and stimulated adipogenesis. Organotin compounds (tributyltin, triphenyltin) in particular more efficaciously suppressed osteogenesis. The second aim characterized the effects of in vivo tributyltin exposure on bone microarchitecture in female C57Bl/6 mice. Tributyltin exposure resulted in a thinner cortical bone, but significantly increased trabecular mineralization. Further analyses suggested that tributyltin did not suppress osteoclast numbers but rather changed osteoclast function, minimally attenuating the resorptive function and enhancing their ability to generate osteogenesis-stimulating factors. Furthermore, tributyltin activated not only PPARγ, but also RXR and liver X receptors. The third aim established the utility of Generalized Concentration Addition in modeling PPARγ activation by mixtures of full and partial PPARγ agonists. A complex mixture of multiple phthalate compounds activated an in vitro PPARγ reporter assay, and the individual dose-responses of each compound were used to construct modeled responses. The comparisons of empirical data and model predictions supported the use of Generalized Concentration Addition in modeling a complex mixture of environmental PPARγ agonists. Together, these studies support and establish important toxicological mechanisms related to PPARγ and RXRα activation in different aspects of bone biology and provide a basis for studying mixture effects of PPARγ agonists.

A study of adsorption equilibria of oxygen, nitrogen and oxygen-nitrogen mixtures on types 4A, 5A, 13X and Na-Mordenite molecular sieve pellets has been made. Pure component isotherms, using a volumetric apparatus, have been measured for each gas on each adsorbent at pressures up to 9 bar and for temperatures of 278.15,293.15 and 303.15 K. Curve fitting of the pure canponent isotherms has been attempted using the kinetic model of Gonzalez and Holland, the vacancy solution model, the statistical thermodynamic model and a mathematical equation similar to the Hill-de Boer model. With the exception of the kinetic model, good curve fitting was obtained. Binary equilibria data have been measured, using a constant volume method, for mixtures of oxygen and nitrogen at pressures of 1.7 and 4.4 bar and at temperatures of 278.15,293.15 and 303.15 K for each of the adsorbents. These results have been presented graphically as equilibrium phase compositions and corresponding total adsorption loadings. The binary experimental equilibria data have been examined against values predicted by mixture models (kinetic model, the extended vacancy solution model, the statistical thermodynamic model, the Cook and Basmadjian model, and the ideal adsorbed solution theory) using regression parameters obtained from the pure component isotherms. The statistical thermodynamic model and the ideal adsorbed solution theory gave the best representation of the experimental data. The activity coefficients of the adsorbed phase for the binary experimental data have been calculated and the results showed no appreciable deviation of the adsorbed phase from ideality. / British Council and the University of Gezira (Sudan)

Existing viscosity prediction methods and relevant literature are reviewed. An exhaustive review of group contribution, corresponding states, and interpolative prediction methods finds that even the best of these models produces large prediction errors and often require significant experimental data. Molecular dynamics simulation techniques for viscosity prediction are evaluated and compared to one another to determine the best choice for this work. A thorough investigation finds that Equilibrium Molecular Dynamics (EMD) simulations are the best option for reproducible and reliable liquid viscosity predictions. The many tuning parameters available in molecular dynamics simulations are investigated for their effects on prediction uncertainty and accuracy. Challenges associated with molecular dynamics predictions are discussed and a rigorous simulation and data analysis methodology is developed which addresses these issues. The TLVMie force field is developed to describe linear alkanes, branched alkanes, alkylbenzenes, and cycloalkanes. The method is developed with a "training set" of compounds and the transferability is evaluated with a completely different "test set" of compounds. Predictive capability with mixture viscosities is evaluated next without any re-fitting of the parameters determined from pure-component data. The TLVMie potential is shown to be significantly more accurate for both pure-components and mixtures, more reliable for compounds that differ greatly from the training set, and predictions are made without the experimental data requirements of other methods.

Asphalt concrete pavements on commercial airports in the United States are constructed according to the Federal Aviation Administration Advisory Circular 150/5370-10B, Item P-401, “Plant Mix Bituminous Pavements.” This specification does not provide guidance for using the Superpave gyratory compactor in the design of asphalt mixtures. This thesis describes a laboratory study of hot mix asphalt (HMA) mix design for airport pavements that uses the Superpave gyratory compactor. These recommendations are based on comparisons of volumetric property measurements of HMA mixtures compacted using Marshall compaction and Superpave gyratory compaction.

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