Iron is among the essential micronutrients for all living organisms and is a cofactor for many cellular redox reactions. Although iron is a highly abundant metal element found in the earth’s crust, it is also a limiting factor in plant development when it is present as insoluble ferric oxides. Plants have evolved two strategies to acquire soluble iron referred to as Strategy I and Strategy II. Our lab has focused on the Arabidopsis thaliana double mutant ysl1ysl3. The mutants display a chlorotic phenotype and are unable to correctly respond to iron deficiency. Grafting is a common method for joining different plant tissues and has been used for studies of long distance signaling. Past studies of iron signaling in Arabidopsis have not been able to provide a mechanism for how plants are able to signal the iron status of the shoot, where iron demand is high, to roots, where iron uptake occurs. The iron signaling experiments included in this thesis follow a seedling-graft approach to understand if grafts are capable of properly sensing iron. A longstanding question of iron homeostasis in plants is the identity of the iron sensors in plants. It was hypothesized that YSL1 and YSL3 have both a transporter function and a receptor function, and therefore function as transceptors. In our predicted model it was proposed that YSL1 and/or YSL3 are directly involved in iron status signaling either in perception and/or transmission of the signal. As evidenced through seedling grafting experiments here, YSLs play a critical part of long distance signaling that plant shoots use to signal their iron status to the roots. In this thesis, YSL1 and YSL3 are shown to be required in the shoots in order for signaling to occur correctly in the roots. To facilitate the analysis of gene expression in the grafts, a FRO3promoter:GUS construct was used in the Col-O WT background. The FRO3 promoter was selected because it is expressed in both leaves and roots under iron deficiency. Experiments showed that the genotype of the shoot used in the grafts is critical for Fe-deficiency induced gene expression in the roots. Thus, grafting has revealed that root iron deficiency responses require YSL1 and YSL3 in leaves for signal transmission. This directly links them to long-distance signaling, and supports the idea that these proteins could be acting as transceptors.

A numerical model is presented to describe solute transport in groundwater coupled to sorption by plant roots, translocation into plant stems, and finally evapotranspiration. The conceptual model takes into account both Root Concentration Factor, RCF, and Transpiration Stream Concentration Factor, TSCF for chemicals which are a function of Kow. A similar technique used to simulate the solute transport in groundwater to simulate sorption and plant uptake is used. The mathematical equation is solved using finite difference technique to solve for the concentration at any grid cell with respect to time. The new package is integrated into SEAM3D to create a new SEAM3D Plant Uptake Package, or PUP. The model is then verified by comparing results for root sorption in one side to the SEAM3D Reaction Package, and results for plant uptake to the SEAM3D Source Sink Mixing Package. The verification results showed an excellent match, which led to using the new package in a series of design application scenarios to evaluate phytoremediation effect. Hypothetical design scenarios included: 1) the effect of a phytoremediation system dimensions, 2) the effect of phytoremediation plant density or maximum ET rate, 3) the effect of out-flux of the phytoremediation with respect to the natural aquifer in-flux, and 4) the effect of using a phytoremediation system when the source of contamination is removed. For all the previous study cases, the results evaluate the effect on: 1) contaminant concentrations downstream the source (expressed in plume length at a concentration 1% of the source concentration), 2) solute mass removal from the aquifer, and 3) mass-flux changes at different cross-sections downstream the contaminant source. The results indicating the followings: 1) the width of the phytoremediation system, WET, has a limited effect on the solute mass-removal; 2) high tree density close to the contaminant source has a greater effect on solute mass removal relative to uniform density of trees planted over the entire plume; 3) the width of the ET area will have only a slight effect on the mass removal if the TSCF value is small; 4) as the value of TSCF gets lower, the efficiency of solute mass uptake is lower, and thus the solute concentration in groundwater is higher regardless of the quantity of water transpired; 5) dynamic steady-state plume dimensions (specially the plume length) are affected by the groundwater in-flux, which will control the dimensions and density of a phyto system; 6) splitting the phyto system into two halves does not have the same outcome of having one piece of area closer to the contamination site; 7) using a phyto system after the contamination source is removed led to increasing the solute concentration in the areas of the trees and decreases the concentration in the areas downstream the trees. The alternative model gives more options for simulation of solute mass uptake by plants by making use of field and lab data between the solute dissolved concentration in groundwater C, and solute mass in tree's core M to select a modeling category of three: Linear (ISO-1), Freundlich (ISO-2), and Langmuir (ISO-3). Each modeling option depends on the designer selection according to the fitted equation parameters between, C and, M. In terms of conservative results, ISO-1, and ISO-2 give less mass removal results than ISO-3 in case of sources with low concentrations. ISO-2, and ISO-3 give less mass removal results than ISO-1 in case of sources with high concentrations. / Ph. D.

Eighteen untrained males [age: 23 +/- 0.6 yr (SEM)] were randomized into high intensity (HIT: above lactate threshold, LT), moderate intensity (LIT: below the LT) or no training (NT) groups. Subjects trained on a cycle ergometer 4 days.wk-1 for 6 wk with the power output held constant. Maximal cycle ergometry was performed before and after the training period to determine changes in power output and oxygen consumption (VO2) at the LT and peak exertion. Before training and after 1, 2, 4, and 6 wk, subjects performed high constant-load (HCL) cycling bouts to quantify training adaptations in the SC. Training was designed to keep total work equivalent between the HIT and LIT groups. Increases in power output and VO2 at LT and peak exercise after 6 wk were noted in the HIT and LIT groups in comparison to NT group (p<0.05). No differences were noted between HIT and LIT. Two-way repeated measures ANOVA revealed a significant trial*group interaction for adaptation in the SC (p<0.001). After 1wk of training, a significant reduction in the SC was noted for HIT [mean+/-SEM]: (pre-training (PT): 703 +/- 61 ml.min-1; 1 wk: 396 +/- 60 ml.min-1) (- 44% from PT). Further adaptation for the HIT was also noted at 4 wk: 202 +/- 45 ml.min-1 (-71% from PT). For LIT, a significant reduction was noted at 2 wk (PT: 588+/-76 ml.min-1; 2 wk: 374 +/- 50ml.min-1) (-36% from PT). Further adaptation for LIT group was noted at 6 wk (252 +/- 38 ml.min-1) (- 57% from PT). Adaptation in SC was not noted at any interval for NT. Temporal changes in blood lactate (r = 0.40) and ventilation (r = 0.72) were significantly correlated with the changes for SC over the 6 wk training period (p<0.05). In conclusion, it was demonstrated that training at supra-LT and sub-LT intensities produces similar improvement in VO2 and power output at peak exercise and in the LT, when total work output is controlled. However, training at supra-LT intensity promotes larger and faster adaptations in the SC than training at the sub-LT levels. / Ph. D.

Direct transpiration rates and plant uptake of naphthalene by a hybrid poplar phytoremediation system located in Oneida, Tennessee were determined using hydrologic and groundwater concentration data. Water table recession analysis techniques were employed to determine direct transpiration rates from the saturated zone of the shallow, unconfined aquifer underlying the site. Direct transpiration rates varied over the growing season (late March to mid-October), with a maximum and mean daily direct transpiration of 0.0100 and 0.0048 feet/day, respectively. During 2004, the maximum direct transpiration rate was observed in May, and rates declined starting in June due to an associated decline in the water table. A technique was developed to estimate the volumetric transpiration rate of each tree based on the breast-height diameters and seasonally variable direct transpiration rates. During peak transpiration, the larger trees at the study site were estimated to directly transpire 4 to 13 gallons per day per tree. Plant uptake rates of naphthalene were estimated by superimposing spatial data (volumetric transpiration rates and naphthalene concentration in groundwater). The mass loss rate of naphthalene from the aquifer as a result of plant uptake during July 2004 was 335 mg/day which only represents 0.117% of the aqueous mass plume. Monthly groundwater profiles showed a decrease of the saturated thickness beneath the system of hybrid poplars between the dormant and active season. This study suggests direct transpiration rates and plant uptake of naphthalene are dependent on variables including climatic parameters, magnitude of the saturated thickness, and the concentration of naphthalene in groundwater. / Master of Science

The STAC3 gene is a functionally undefined gene predicted to encode a protein containing two SH3 domains and one cysteine-rich domain. In this study, we determined the potential role of the STAC3 gene in proliferation and differentiation of bovine satellite cells. We isolated satellite cells from skeletal muscle of adult cattle and transfected them with STAC3 small interfering RNA (siRNA) or scrambled siRNA. Cell proliferation assays revealed that STAC3 knockdown had no effect on the proliferation rate of bovine satellite cells. We assessed the differentiation status of bovine satellite cells by quantifying the expression levels of myogenin and myosin heavy chain genes, and by quantifying fusion index. STAC3 knockdown stimulated mRNA and protein expression of myogenin, and myosin heavy chain 3 and 7, and increased fusion index of bovine satellite cells. These data together suggest that STAC3 inhibits differentiation of bovine satellite cells into myotubes. To determine the underlying mechanism, we identified and validated AP1?1 as a STAC3-interacting protein by yeast two-hybrid screening and co-immunoprecipitation. In C2C12 cells, STAC3 knockdown decreased the expression level of AP1?1 protein. In bovine satellite cells, STAC3 knockdown increased the membrane localization of glucose transporter 4 (GLUT4) and glucose uptake. These data together suggest the following mechanism by which STAC3 inhibits differentiation of bovine satellite cells: STAC3 increases AP1?1 stability in cells; a high level of AP1?1 keeps GLUT4 from translocating to the plasma membrane; reduced membrane localization of GLUT4 impedes glucose uptake; and restricted glucose uptake inhibits differentiation of satellite cells into myotubes. / Master of Science

Measuring V02peak is an important health assessment used to indicate cardiorespiratory fitness, prescribe exercise, and diagnose heart abnormalities (2,12). Utilizing the muscles of the upper body, the new StairMaster kayak ergometer is ideal for measuring V02peak on people with lower extremity disorders and those whose occupational or recreational activities rely primarily on the muscles of the upper body (16). Twenty-four healthy college-aged (17-31 years) males and females were screened, gave informed consent, and received orientation to experimental procedures prior to participation in the study. Subjects performed two maximal exercise bouts on the kayak incremental protocol and one on the treadmill incremental protocol. Pearson's r correlation estimated the stability-reliability coefficient of the kayak protocol to be 0.84. Pearson's r correlation estimated the relationship of the kayak protocol to the treadmill protocol to be 0.69. Given performance on the kayak ergometer, the predictive equation for treadmill performance was Y = 11.2605 + 1.02748X (r = 0.48). Body mass index and forearm circumference were found to be adequate predictors of kayak performance using the equation 45.2 - 1.60 BMI + 1.03 Forearm (~ 0.49). Although the kayak incremental protocol demonstrates adequate test-retest reliability for measuring V02peak, it has only a fair relationship to the gold standard of uphill treadmill running. The kayak incremental protocol, therefore, is generally best suited for those who, due to lower extremity complications, are unable to perform traditional modes of testing, or for those whose occupational or recreational activity is dominated by the upper body. / Master of Science

We investigated the influence of multiple disturbances on ecosystem structure and function in a headwater stream adjacent to an abandoned arsenic mine using an upstream (reference) and downstream (mine-influenced) comparative reach approach. In this study, floods were addressed as a pulse disturbance, and the abandoned arsenic mine was characterized as a press disturbance. Chronically elevated levels of arsenic were specifically addressed as a ramp disturbance. Stream ecosystem structure and biogeochemical functioning were characterized monthly over a period from July to December 2004 by determining benthic organic matter standing stocks, ecosystem metabolism, and by using solute additions to examine differences in phosphorus uptake and hydrology over the monitoring period. Influences of the press disturbance were evident in the mine-influenced reach where arsenic concentrations (254 ± 39 µg/L) were >30 higher than in the reference reach (8 ± 1 µg/L). However, in almost all cases the presence of the abandoned arsenic mine appeared to exert little influence on reach-scale measures of ecosystem structure and function (e.g., organic matter standing crops, phosphorus uptake). Conversely, floods (i.e., pulse disturbances) influenced organic matter standing stocks and hydrologic interactions between the stream and transient storage zones in both study reaches. Interactions between press and pulse disturbances were evident in several cases and illustrated by phosphorus uptake responses. Phosphorus uptake was best predicted by coarse particulate organic matter standing stocks in the reference reach. However, in the reach exposed to the press disturbance (i.e., mine-influenced reach), both coarse particulate organic matter standing stocks and characteristics of the pulse disturbance regime (i.e., number of days post-flood) were significant predictors of phosphorus uptake. Within the mine-influenced reach, arsenic concentrations increased from 16–600 µg/L and were addressed as a ramp disturbance. Analysis of phosphorus uptake in the mine-influenced reach across a gradient of arsenic concentrations correlated with Michaelis-Menton models of enzyme kinetics in the presence of a competitive inhibitor. These results suggest that arsenic appears to competitively inhibit phosphorus uptake by microbial assemblages in the mine-influenced reach. Results from this study highlight the fact that ecotoxilogical studies at the ecosystem scale should consider not only contaminant influences, but rather place its implications within the extant disturbance regime generated from both natural and anthropogenic sources. / Master of Science

As anthropogenic nutrient loads threaten the health of the Chesapeake Bay, lotic processes throughout its headwaters may buffer increased nitrogen inputs by converting them to stable forms, ultimately through denitrification to N2 gas. However, the temporal environmental factors controlling baseflow nitrogen retention are poorly understood, particularly temperature, shading, and dissolved organic matter dynamics. This study therefore attempts to elucidate the effects of these environmental variables on nitrogen cycling within the Fair Hill Natural Resources Management Area (Fair Hill), a forested watershed within the Piedmont physiographic province of the Chesapeake Bay. As expected, groundwater and allochthonous organic matter inputs set the foundation for lotic biogeochemistry at Fair Hill, creating a nutrient-limited, heterotrophic reach. Within this setting, three temporal "hot-moments" of in-stream nutrient processing were observed: the release of ammonium and phosphate during the warm - but shaded - growing season; nitrate uptake during autumnal leaf-fall; and a unique spike of nitrate uptake and respiration-induced degradation of labile organic matter during a drought. Consequently, the baseflow capacity of this headwater stream to buffer nutrient exports to the Chesapeake Bay constantly varies throughout the year in response to light availability, temperature, and in-stream organic matter dynamics. / Master of Science / Throughout the Chesapeake Bay watershed, ecological processes known as nitrogen retention can naturally remove nitrogen pollution from small streams (a.k.a. headwater streams), and hence the Chesapeake Bay watershed. However, in-stream nitrogen retention varies throughout the year due to seasonal changes in temperature, shading (as leaves grow in the spring or fall off in the fall), and the amount and type of organic matter in the stream. This study examines how these three variables (temperature, shading, and dissolved organic matter dynamics) affect nitrogen retention in a headwater, forested stream within the Fair Hill Natural Resources Management Area (Fair Hill) located in the Piedmont region of the Chesapeake Bay watershed. As expected, groundwater and organic matter inputs set the foundation for in-stream conditions at Fair Hill, creating an environment with low concentrations of nitrate and phosphate (thus causing the stream to be nutrient-limited), while also creating a heterotrophic environment, which is an environment where more oxygen is consumed by microbes than produced by algae and plants. Additionally, three seasonal patterns regarding in-stream nutrient dynamics were observed at Fair Hill. Firstly, in-stream ammonium and phosphate concentrations increased during the warm - but shaded - growing season. Secondly, in-stream nitrate concentrations decreased when leaves fell in the fall. Thirdly, during a drought, in-stream nitrate removal increased while in-stream organic matter became more degraded. Consequently, in-stream nutrient retention at Fair Hill varies constantly throughout the year in response to light availability, temperature, and in-stream organic matter dynamics.

Yes / Implementation and uptake of novel and cost-effective medicines can improve patient health outcomes and healthcare efficiency. However, the uptake of new medicines into practice faces a wide range of obstacles. Earlier reviews provided insights into determinants for new medicine uptake (such as medicine, prescriber, patient, organization, and external environment factors). However, the methodological approaches used had limitations (e.g., single author, narrative review, narrow search, no quality assessment of reviewed evidence). This systematic review aims to identify barriers and facilitators affecting the uptake of new medicines into clinical practice and identify areas for future research. A systematic search of literature was undertaken within seven databases: Medline, EMBASE, Web of Science, CINAHL, Cochrane Library, SCOPUS, and PsychINFO. Included in the review were qualitative, quantitative, and mixed-methods studies focused on adult participants (18 years and older) requiring or taking new medicine(s) for any condition, in the context of healthcare organizations and which identified factors affecting the uptake of new medicines. The methodological quality was assessed using QATSDD tool. A narrative synthesis of reported factors was conducted using framework analysis and a conceptual framework was utilised to group them. A total of 66 studies were included. Most studies (n = 62) were quantitative and used secondary data (n = 46) from various databases, e.g., insurance databases. The identified factors had a varied impact on the uptake of the different studied new medicines. Differently from earlier reviews, patient factors (patient education, engagement with treatment, therapy preferences), cost of new medicine, reimbursement and formulary conditions, and guidelines were suggested to influence the uptake. Also, the review highlighted that health economics, wider organizational factors, and underlying behaviours of adopters were not or under explored. This systematic review has identified a broad range of factors affecting the uptake of new medicines within healthcare organizations, which were grouped into patient, prescriber, medicine, organizational, and external environment factors. This systematic review also identifies additional factors affecting new medicine use not reported in earlier reviews, which included patient influence and education level, cost of new medicines, formulary and reimbursement restrictions, and guidelines. PROSPERO database (CRD42018108536). / This work presents research funded by the Pharmacy Research UK (grant reference: PRUK-2018-GA-1-KM) and Leeds Teaching Hospitals NHS Trust.

NASEM (2021) recently made strides in characterizing effects of 5 individual EAA on milk protein production. However, there are 15 other AA that are incorporated into milk protein, and as such, these AA likely also play significant roles in driving milk protein synthesis, but lack of data prevents their incorporation into current models. A greater supply of AA to the mammary glands does not always mirror AA absorption—the process by which absorbed AA convert into milk protein is variable, and this may be linked to the way the udder regulates AA uptake to preserve intracellular balance. AA transporters housed within the cellular membranes of mammary epithelial cells (MEC), the mammary glands' constituents, are responsible for mediating this intracellular balance. Thus, the objectives of this dissertation were to investigate how AA transport is affected by various AA concentrations using both in vitro and in vivo approaches. In study 1, we evaluated effects of valine and a group of NEAA (AQG; Ala, Gln, and Gly) on exchange transport rates of AA in bovine MEC. High AQG concentrations stimulated Leu, Phe, and Val influx rate parameters, demonstrating that AQG likely increased transport activity for these substrates through exchange transporters. Additionally, high Val concentrations decreased Ile and Leu net uptakes, which occurred via efflux stimulation and transamination downregulation. In study 2, we aimed to identify the effects of 10 EAA and 2 Tyr (CDENSPY) on transport rates and transporter regulation (mRNA expression and protein abundance). Within the physiological AA concentrations used, we were able to measure differential effects of AA on each AA transporter. For example, His stimulated SLC38A2 and SLC38A2 mRNA expression at a decreasing rate; the apex for this curve was reached at a concentration very close to mean plasma concentrations in lactating dairy cows. Therefore, we determined that these transporters may be transcriptionally regulated to regulate intracellular His concentrations. Additionally, all EAA and NEAA groups were involved in significant 2-way interactions on transporter expression and activity. Furthermore, we measured transport rates and rate constants (free of mass influence) of 12 AA to determine important AA on influx, efflux, transamination, irreversible loss, and protein synthesis. We demonstrated competitive inhibition among several AA that share transport systems such as between BCAA. Furthermore, we again demonstrated that NEAA can stimulate transport activity for AA involved in exchange transport. In study 3, we investigated the effects of jugular Lys, Ile, Val, or AQG infusion on mammary AA metabolism and production in lactating dairy cows. Interestingly, Val decreased DMI and milk protein production along with net uptakes of several AA, while the remaining treatments had little metabolic effects. In study 4, we demonstrated that both high protein and starch concentrations independently stimulated milk protein production, but glucose precursor partitioning (lactate, propionate and other) was only affected by starch. In conclusion, we anticipate that nutrition models estimating milk protein production will eventually incorporate up to 20 AA and multiple 2-way interactions; additionally, extremely high concentrations of AA should be prevented to combat negative impacts caused by AA imbalances. However, much more work is required to take steps in this direction. / Doctor of Philosophy / Overfed protein can pose a significant health and environmental risk. Unabsorbed amino acids (AA), the building blocks of protein, are released by dairy cattle into the environment as various nitrogen products. One specific risk is excess runoff of nitrates from dairy farms into nearby water bodies. This contamination can result in serious water quality issues, including eutrophication, which depletes O2 levels in aquatic ecosystems with algae overgrowth, causing dead zones where aquatic life cannot survive. Furthermore, high nitrate levels in drinking water can decreased oxygen availability in humans, in which pregnant women and babies are the most at risk. Finally, the volatilization of N compounds also contributes to air pollution and the formation of greenhouse gases like nitrous oxide, a potent climate-altering compound with global warming potential. Theoretically, feeding an AA profile to precisely match dairy cow requirements would minimize these losses. However, the udder does not take up all available AA. Thus, this research aimed to better understand different AA profiles on AA transport, the route in which AA are taken up by the milk-producing cells in the cow's udder, to ultimately increase efficiency of milk production. In our first study, we demonstrated that non-essential AA (Ala, Gln, and Gly), which can be synthesized in the mammary glands, stimulated Leu, Phe, and Val transport activity within mammary epithelial cells, which could mean that supplemental non-essential AA could increase essential AA transport efficiency. Interestingly, high Val had a negative effect on net uptake (entry minus exit) of Leu and Ile. The second study sought to understand how varying concentrations, within ranges observed in the blood of lactating dairy cows, of 10 different essential AA and 2 non-essential AA groups affected AA transporter expression and activity. We observed greater protein presence and mRNA expression levels of several transporters in response to low availability of their AA transport substrates. Additionally, some AA were involved in stimulating transporter expression and activity when present at high concentrations, such as Leu. There was a plethora of 2-way interactions among AA on transporter protein quantity, mRNA expression, and activity that indicated that the relationship between certain AA will need to be incorporated into future nutrition models. In our third study, we observed that high Val supply decreased the amount that cows ate as well as their milk protein production. This demonstrated that excessive concentrations of certain AA may negatively affect cow metabolism. Lastly, we wanted to investigate the relationship between protein and glucose production in dairy cows, as energy availability is another driver of milk protein production. Our fourth study revealed that dietary protein and starch independently increased milk protein production, yet only starch affected glucose formation. Our findings urge caution against excessive AA concentrations in diets, as imbalances can have negative effects. Overall, we have demonstrated that AA transporters are differentially affected by changes in individual AA supply and various 2-way interactions. This work unveiled the almost unlimited AA interactions that must be further explored to better integrate this knowledge into practical dietary formulations for dairy cows.