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Organisms have evolved a remarkable ability to mineralize complex skeletons and functional biomaterials. These structures are nucleated and grown in close associaiton with macromolecular assemblages of proteins and polysaccharides that are implicated in regulating all stagees of mineralization. Because of this intimate association of organic with inorgaic components, many studies have investigated the effects of particular organic species on mineral morphology, phase, and growth rate. However, the diversity and species-specific nature of the organic assemblages associated with biominerals across a wide variety of taxa, has limited our understanding of how organisms use biomolecules to regulate skeletal formation. It is clear that a mechanistic picture of biomolecular controls on mineralization requires molecular-level investigations of the interplay between organic and inorganic components at all stages of crystallizaiton. This dissertation presents the findings from theoretical and experimental studies of the physical mechanisms that underlie biomolecule controls on mineral formation. Molecular dynamics simulations probe the effects of acidic molecules on the hydration of alkaline earth cations. After first calculating baseline hydration properties for magnesium, calcium, strontium, and barium, I determine the effects of carboxylate-containing molecules on cation hydration state as well as the kinetics and thermodynamics of water exchange. Experimental work utilizes self-assembled monolayers as proxies for matrix macromolecules in order to understand their effects on CaCO3 nucleation kinetics and thermodynamics. Estimates of nucleation rates and barriers are made from optical microscopy data and correlated with measurements of crystal – substrate rupture force from dynamic force microscopy. These investigations show that an important function of biomolecules in directing mineralization lies in their ability to modulate cation hydration. Both chemical functionality and molecular conformation are influential in regulating the kinetics and thermodynamics of mineral nucleation, and these effects may be predicted by the strength of interaction between organic and inorganic components. These findings contribute to a mechanistic understanding of how organic matrices act to regulate biomineral formation. They demonstrate a plausible physical basis for how carboxyl-rich biomolecules accelerate the kinetics of biomineral growth and suggest roles for organic species in the nucleation and pre-nucleation stages of mineralization. / Ph. D.

Studying dynamics of proteins in their biological milieu such as water is interesting because of their strong absorption in the terahertz range that contain information on their global and sub-global collective vibrational modes (conformational dynamics) and global dynamical correlations among solvent water molecules and proteins. In addition, water molecules dynamics within protein solvation layers play a major role in enzyme activity. However, due to the strong absorption of water in the gigahertz-to-terahertz frequencies, it is challenging to study the properties of the solvent dynamics as well as the conformational changes of protein in water. In response, we have developed a highly sensitive megahertz-to-terahertz dielectric spectroscopy system to probe the hydration shells as well as large-scale dynamics of these biomolecules. Thereby, we have deduced the conformation flexibility of proteins and compare the hydration dynamics around proteins to understand the effects of surface-mediated solvent dynamics, relationships among different measures of interfacial solvent dynamics, and protein-mediated solvent dynamics based on the complex dielectric response from 50 MHz up to 2 THz by using the system we developed. Comparing these assets of various proteins in different classes helps us shed light on the macromolecular dynamics in a biologically relevant water environment. / Doctor of Philosophy / Proteins are complicated biomolecules that exist in all living creatures and they are, mostly, involved in building up structures and cell functions in various biological systems. Not only their existence but also their complex movements and dynamics are vital to cell functions in living beings. Until recently, their chemical functions and dynamics have been extremely challenging to investigate and track in their native environments. Thanks to various efforts by researchers all over the world to learn more about their convoluted behavior, new techniques have arisen to study these properties. We, as a part of this community, have been able to develop highly sensitive megahertz-to-terahertz dielectric spectroscopy system to probe proteins and other biomolecules dynamics in picosecond to microsecond range. Using our benchmark system, we have been able to map the detailed dynamical properties of biomolecules as well as their exclusive hydration shell characterizations. In this work, we gathered details about three well-known proteins and biomolecules by studying their dielectric responses. Thus, we have been able to discuss the movements, relaxation processes and hydration shell properties of these molecules in liquid water as their basic native environment.

Adequate hydration is critical for optimal performance and health. Fluid requirements of collegiate athletes are unique due to training and competition, travel, school schedules, and stressors common in college environments. Inattention to these factors may contribute to suboptimal hydration. Importantly, loss of 1-2% of body weight by dehydration can impair physical and cognitive performance. As such, development of valid and reliable tools to assess hydration status in collegiate athletes is needed. The purpose of this study was to assess the validity of urine color (UC) as a measure of hydration status in collegiate athletes. A secondary purpose was to evaluate the utility of indexes of hydration status for UC and urine specific gravity (USG) established by the American College of Sports Medicine (ACSM) and the National Athletic Trainers' Association (NATA). To address this, 62 NCAA Division I collegiate athletes provided a urine sample ≤30 minutes of exercise for UC self-assessment (UCsub) and experimenter-assessment (UCres) using the UC chart developed by Armstrong et al. (1994) and for USG measurement via refractometry (1). Habitual dietary intake was assessed by 24-hr recalls. There was a significant positive correlation between USG and both UCsub (r=0.679, p<0.001) and UCres (r=0.772, p<0.001). In addition, the USG based on UC was inconsistent with hydration/dehydration categories established by ACSM and NATA. These findings suggest that UC, even when self-assessed by the athlete, is a valid method for assessing hydration status in NCAA division I college athletes. However, some modification of ACSM and NATA hydration categories may be warranted. 1. Armstrong LE, Maresh CM, Castellani JW, et al. Urinary indices of hydration status. Int J Sport Nutr. 1994;4(3):265-279. http://www.ncbi.nlm.nih.gov/pubmed/7987361. Accessed October 26, 2016. / Master of Science

Background: Training, travel, and competition can make an athlete's fluid needs different from the general population. As such, there is a need for an acceptable tool to determine the unique beverage intake habits of athletes. The BEVQ-15 is one such tool to determine beverage intake over time but has not yet been confirmed for accuracy in college athletes. Objective: The purpose of this study is to evaluate the validity and reliability of the beverage questionnaire (BEVQ-15) for measuring fluid intake in collegiate NCAA athletes. Design: Athletes were recruited from two NCAA Division I universities. The individuals in this study (n=61) completed two short BEVQ-15 surveys plus three dietary recall interviews administered by trained diet technicians to compare the surveys against. The two surveys were administered at least three days apart and the 24-hour dietary recalls included two weekdays and one weekend day. Results: This study included 61 athletes at the conclusion. Comparing the BEVQ-15 to the 24-hour recall standard, Spearman's rho correlation tests found that 7 of the 15 categories are significant at P≤0.01 when comparing fluid ounces, while 5 of the 14 categories are significant at P≤0.01 when comparing kcal consumed. An additional 3 categories for both ounces and kcal consumed are significant at P≤0.05. With these findings, validity criteria are met. Fruit juice, sweetened fruit juice, low fat milk, diet soft drinks, sweetened tea or coffee, and hard liquor are not strongly correlated between testing methods in the collegiate athlete population. Pearson correlations demonstrated significant reliability comparing BEVQ-15 responses of test one and two for all but one category for ounces consumed and three for calories consumed at P≤0.01. The results of Bland-Altman suggested acceptable limits of agreement between the two measures. Follow up linear regression models indicated no proportional bias. Conclusions: The BEVQ-15 is a valid tool for the assessment of beverage intake in an NCAA Division I athlete population. As such, the BEVQ-15 may be a useful tool for assessing beverage intake and patterns in collegiate athletes. / MS / How hydrated an athlete is can play a major role in their physical performance and overall health1. Athletes may have unique fluid needs that depend, at least in part, on the timing, volume, and type of beverage consumed and the needs required by their training and competition specific to their given sport. Training, travel, and competition can make an athlete’s fluid needs different from the general population. As such there is a need for an acceptable tool to determine the beverage intake habits of athletes. This makes a short survey asking about drink consumption desirable for this population. The BEVQ-15 fits this description but has not yet been confirmed for accuracy in college athletes. Therefore the purpose of this study is to prove the accuracy of using drink survey (BEVQ-15) in measuring beverage intake in collegiate NCAA athletes. To do so, this study will look at results from 61 NCAA collegiate athletes recruited from Virginia Tech and Radford Universities. The participants completed two short BEVQ-15 surveys as well as three dietary recall interviews to compare the surveys against. The BEVQ-15 surveys were repeated on two occasions and found to be reliable. The beverage (and food) intake from the recalls was analyzed using dietary analysis software, compared to the data obtained by the BEVQ-15, and found to be a valid tool to assess beverage intake patterns among NCAA Division I collegiate athletes.

Student Number : 9900772K - MSc research project - School of Civil and Environmental Engineering - Faculty of Engineering and the Built Environment / The hydration of cement is an exothermic reaction, which begins almost immediately upon contact with water. This produces a large amount heat that subsequently raises the temperature of the concrete mixture, creating a temperature gradient across the member. The temperature rise associated with hydration induces thermo-mechanical stresses. These stresses can cause damage to the structure, affecting the durability and in extreme cases the functionality of the structure. If the maximum rate of heat evolution experienced can be minimised through the selection of the constituents of a concrete mixture, then the thermal stresses that develop in the concrete can be reduced. The main aim of this research is to develop a knowledge of how the heat evolution characteristics of concrete are affected by changing certain concrete mixture parameters and ingredients. The focus is on the addition of three different cement extenders and varying the water/cement ratio. This will be a step towards the development of a model for predicting the thermal properties of concrete. As a part of this investigation, a prediction model for the change in heat rate in concrete was developed. The model is intended to predict the contribution of the individual clinker crystallographic phases in cement and the heat liberated in concrete during hydration.

Mixes with lower water to cement (w/c) ratio and supplementary cementing materials produce strong and durable concrete. The consequence of lowering w/c is an increase in autogenous shrinkage (AS), which contributes to concrete cracking. Internal curing (IC) is shown to mitigate AS, however improper dosing of IC material can negatively affect the concrete properties. The effectiveness of IC material, such as superabsorbent polymer (SAP), depends on the 1) amount of water stored, 2) particle distribution, and 3) ability to deliver water. The objective of this research is to quantify the in-situ efficiency of SAP by investigating its effect on the cement chemical reaction using non-destructive testing methods, specifically isothermal calorimetry and nuclear magnetic resonance (NMR). IC was tested with varying quantities of SAP in plain cement paste using white Portland cement and three w/c (0.30, 0.32, 0.35). Overdosing of the SAP material was found to significantly affect the hydration reaction and reduce the efficiency of the material. The initial porosity of the paste influences the ability of IC to provide water. However, the extra porosity provided by SAP needs to be considered when calculating the degree of hydration. Particle agglomeration occurs when the mass of SAP to IC water is greater than 5% and is the main factor causing loss of efficiency. A new geometric model was developed to estimate the SAP distribution within the cement paste. The model employs the SAP absorption determined by NMR and assumes that the SAP particles are spherical, of equal diameter, and individual particles absorb the same amount of pore solution. The results reveal that particle spacing increases with agglomeration and reduces the IC efficiency. A hybrid 1-D finite element transient flow model was developed to reverse engineer the effective diffusion coefficient from the NMR water distribution. The gel solid volume fraction and its impedance to water transfer were accounted for through the cement degree of hydration and tortuosity factor, respectively. Model results reveal that the effective water diffusion coefficient depends on w/c, gel volume fraction, and tortuosity once the cement gel fractions start to connect, i.e., after 20% cement degree of hydration. The diffusion length quantifies the distance water can transfer from the SAP to the cement paste. / Thesis / Doctor of Philosophy (PhD)

The thesis, which contains nine chapters, reports extensive large scale atomistic molecular dynamics (MD) simulation studies of water structure and dynamics at the surface of an anionic micelle, hydration layer of two proteins, and in the grooves of a 38-base pairs long DNA. Understanding the structure and dynamics of water molecules at the surfaces of self-organized assemblies and complex biological macromolecules has become a subject of intense research in recent times. Chapter 1 contains a brief overview of the biomolecular hydration dynamics. Relevant experimental, computational, and theoretical studies of biomolecular hydration and the time scales associated with the water dynamics are discussed. In Chapters 2 and 3, the structure, environment, energetics, and dynamics of constrained water molecules in the aqueous anionic micelle of cesium perfluorooctanoate (CsPFO) have been studied using large scale atomistic molecular dynamics simulations. Based on the number of hydrogen bond (HB) that interfacial water molecule makes with the polar head group (PHG) oxygen of the micelle, we find the existence of three kinds of water at the interface. We introduce a nomenclature to identify the species as IBW2 (form two HBs with two different PHG), IBW1 (form one HB with PHG), and IFW (no HB with PHG). Despite of possessing two strong w-PHG bonds, the concentration of the IBW2 species is rather low due to entropic effect. The ion solvation dynamics study at the interface shows the presence of a slow component, with a relaxation time 1-2 order of magnitude slower than that in the corresponding bulk solvent in agreement with the experimental results. Both the translational and orientational dynamics of the water molecules near the micellar surface is found to be much slower than those in the bulk. The HB between the PHG of the micelle and the water molecule has almost 13 times longer life time than that in the bulk between two tagged water molecules. In Chapter 4, we present results of extensive atomistic MD simulation studies of the structure and dynamics of aqueous protein solution of the toxic domain of Enterotoxin (1ETN) and the chicken villin headpiece sub-domain containing 36 amino acid residues (HP-36). Reduced water structure and the faster water dynamics around the active site of these proteins have been observed which may have biological significance. Chapter 5 presents an extensive atomistic molecular dynamics simulations study of water dynamics in the hydration layer of a 38 base long hydrated DNA duplex. The computed rotational time correlation function (TCF) of the minor groove water dipoles is found to be markedly non-exponential with a slow component at long time. The constrained water molecule is also found to exhibit anisotropic diffusion in both the major and minor grooves. At short-to-intermediate times, translational motion of water molecules in minor groove is sub-diffusive. Chapter 6 presents the study of water entropy in both the grooves DNA. The average values of the entropy of water at 300K in both the grooves of DNA are found to be significantly lower than that in bulk water. We propose that the configurational entropy of water in the grooves can be used as a measure of the mobility (or micro viscosity) of water molecules in a given domain. In Chapter 7, we study the specific DNA base-water hydrogen bond lifetime (HBLT) dynamics at the major and the minor grooves of a hydrated duplex. The base-water HBLT correlation functions are in general multi-exponential and the average lifetime depends significantly on the specificity of the DNA sequence. The average HBLT is longer in the minor groove than that in the major groove by almost a factor of 2. Chapter 8 presents the solvation dynamics of constituent bases of aqueous DNA duplex. The solvation TCFs of the four individual bases display highly non-exponential decay with time. An interesting negative cross-correlation between water and counterions is observed which makes an important contribution to relaxation at intermediate to longer times. In the concluding note, Chapter 9 presents a brief summary of the outcome of the thesis and suggests several relevant problems that may prove w orthwhile to be addressed in future