<p>Hermetic storage systems have gained global popularity for their ability to minimize stored product losses by depleting oxygen. However, relying solely on insects to deplete oxygen in hermetic storage, when this process takes longer, can result in (further) damage to stored commodities. This study was conducted to investigate: (i) the potential of four different germinating seeds (soybean, rice, cowpea, and corn) in scavenging oxygen within hermetic storage systems; (ii) the impact of container volume and the number of germinating seeds on oxygen depletion; and (iii) the effects of germinating seeds on insect mortality and grain quality. Among the crops tested, cowpea, during their fourth, fifth, and sixth germination stages (T4, T5, and T6), depleted oxygen below 5% within 12 hours. The fourth stage of cowpea (T4) was identified as a potential oxygen scavenger due to its shorter germination time and ease of handling. Moreover, increasing the number of germinating seeds resulted in a faster initial rate of oxygen depletion in all-sized jars. Doubling both the volume of the jars and the number of germinating seeds had a similar rate of oxygen depletion. Additionally, an equation was derived to predict the required number of germinating seeds based on data from different numbers of seed and container volume combinations. Relative humidity levels increased to approximately 90% when empty jars were used but remained consistent at 40% when the jars were filled with grains. Furthermore, using 10, 20, and 30 germinating cowpea seeds with stored grains and insects, oxygen levels were reduced below 5% at different time intervals. Complete adult mortality of <em>C. maculatus</em> was achieved within 3-5 days of exposure, depending upon the number of germinating seeds. 20 and 30 seeds achieved complete mortality within 72 hours, while 10 seeds required 120 hours. As the number of germinating seeds increased, egg counts decreased, and moisture content significantly increased in the treatment involving 30 seeds. Furthermore, no adult emerged after 96 and 120 hours of exposure to normoxia for the 30 and 20 seed treatments, respectively. However, in the 10 seeds treatment, a small percentage of adults (0.29%) did emerge even after 120 hours of exposure.</p>

<p>The data in this dissertation describes changes in metabolic flux in bovine cell culture and bovine hepatic models. </p>

<p>Germination testing and seedling vigor for Kentucky bluegrass germination. Analyzing growth from Kentucky bluegrass cultivars. </p>

<p dir="ltr">Stocking density, space availability, and lameness are important aspects affecting broiler chicken behavior and welfare. Stocking density refers to the weight of broiler chickens per a set area of space typically measured as kg/m2. Space availability is the amount of space per individual broiler chicken typically measured as m2/bird. Stocking density and space availability can contribute to lameness and other aspects of welfare such as footpad dermatitis, hock burn, and feather cleanliness. The behavior of broiler chickens can also be modified by stocking density, space availability, and lameness. All of these aspects are typically related to a change in activity levels which could be used as an indicator of animal welfare. To date, the majority of research that has examined the walking ability of broiler chickens has assessed how stocking density influences the development of gait problems when applied during the grower phase. However, not all broilers develop gait problems at the same point in time and it is unknown whether broilers that initially have sound gait develop gait problems at a similar rate to broilers that are initially classified as having affected gait. Further, the influence of stocking density on the progression of gait abnormalities of broilers with sound and poor gait is unknown. Finally, since space becomes more and more limited as broiler chickens increase in body weight and age, it is unknown how the provision of space during the finisher phase, when broiler chickens are gaining weight rapidly, can influence their walking ability and welfare outcomes. Stocking density is calculated based on projected final weights of broiler chickens from the time they are placed on a commercial farm, and that projected stocking density remains the same from the chick placement date. As stocking densities are increased, there is also an increase in the prevalence of lameness. Age is also known to be related to walking ability, and as broiler chickens age, there is an increase in the prevalence of lameness. While it is known that increasing stocking density and aging are both contributing factors to broiler chicken lameness, there is no previous research on if reducing stocking density at a later age can help alleviate the prevalence of lameness. To address this knowledge gap, two studies were conducted. In the first study, 784 mixed-sex Ross 708 broiler chickens in commercial barns were placed into of four treatment groups. · SOUND: Consisted of broiler chickens that were considered to have sound gait (scores of 0 and 1) and the broilers were housed at farm stocking density (6lb/ft2, 29.29 kg/m2), · AFFECTED: Consisted of broiler chickens that were considered to have affected gait (scores of 2 or higher) and were housed at farm stocking density (6lb/ft2, 29.29 kg/m2) · MIXED-F: Consisted of 50% of broiler chickens that were considered to have sound gait and 50% that were considered to have affected gait and were housed at farm stocking density (6lb/ft2, 29.29 kg/m2) · MIXED-L: Consisted of 50% of broiler chickens that were considered to have sound gait and 50% that were considered to have affected gait and were housed at half of the farm stocking density (3lb/ft2, 14.65 kg/m2) Broiler chickens were randomly selected at 33 days of age from each of four commercial barns for welfare assessments, which included gait scoring to assess walking ability, as well as the assessment of footpad dermatitis and hock burn. Broilers were then assigned to one of two gait categories based on their gait scores. Broilers were either considered to have sound gait meaning they had no or unidentifiable abnormalities, or affected gait meaning there were identifiable abnormalities. To separate treatment groups, custom-built pens (4 ft x 12 ft, 1.22 m x 3.66 m) were constructed. At 37 days of age welfare assessments were conducted again, and then the broiler chickens were placed back into the flock (Chapter 2). The behavior of the broiler chickens was recorded from the evening of day 33 to the morning of day 37 and video was analyzed using scan sampling. The proportion of broiler chickens performing target behaviors was recorded every 10 minutes in the morning (6:00 – 8:00) and evening (19:00 – 21:30). Better gait scores were observed at 37 days of age in broiler chickens in the MIXED-L group and broiler chickens in the SOUND group. The presence of hock burn was lower in broiler chickens in the SOUND group. Cleanliness scores were better for broiler chickens in the MIXED-L group and in broiler chickens in the SOUND. Stocking density impacted the proportion of broilers performing eating, drinking, sitting, and walking (P < 0.05). Walking ability impacted the proportion of broiler chickens standing, walking, and sitting (P < 0.05). To continue investigating the implementation of housing changes later in the broiler chickens’ life, a second study was conducted using 705 mixed-sex Ross 708 broiler chickens. At 7 d, broiler chickens were randomly assigned to 1 of 16 pens (46-47 birds/pen). At 28 d, half of the pens doubled in size after welfare assessments were completed (measuring 8 ft x 10 ft, 3.05 m x 2.44 m, DOUBLE), while the other half remained at the original dimensions (8 ft x 5 ft, 2.44 m x 1.5 m, SINGLE). The DOUBLE pens had an expected stocking density of 15.2 - 15.5 kg/m2 (3.11 - 3.17 lb/ft2) and an estimated space availability of 0.15 to 0.16 m2/bird while the SINGLE pens had an estimated stocking density of 30.4 - 31.1 kg/m2 (6.23-6.37 lb/ft2) and an estimated space availability of 0.07-0.08 m2/bird. Welfare assessments consisting of scoring gait, feather cleanliness and for the presence of FPD and hock burn were conducted at 22 d, 28 d, and 38 d (Chapter 4). At 38 d, broiler chickens in SINGLE pens were less likely to have a score of 0 for FPD (Wald c2 = 15.45, P < 0.0001), hock burn (Wald c2 = 7.26, P = 0.0071), and feather cleanliness (Wald c2 = 11.77, P = 0.0006) than broiler chickens in DOUBLE pens. However, broiler chickens in SINGLE pens were more likely to have a gait score of 0 compared to broiler chickens in DOUBLE pens (Wald c2 = 11.34, P = 0.0008). Broiler chicken behavior was recorded at 23-26 d (Period 1: before space increase), 28-31 d (Period 2: time of space increase), and 36-37 d (Period 3: after space increase). Behavior data were collected using focal sampling for two broiler chickens per each of the 16 pens in the morning, afternoon, and evening (Chapter 5). Broiler chickens housed in double pens had an increased frequency of leg extensions compared to broiler chickens housed in single pens (P < 0.05). Period had a significant impact on the frequency of eating, sitting, and walking and the durations of sitting, environmental pecking, standing, and walking (P < 0.05). Time of day had a significant impact on the frequency of eating, sitting, walking, preening, and leg extensions and the durations of sitting, eating, preening, and standing (P < 0.05). The interaction of age and time of day had a significant impact on the frequency of drinking and leg extensions and the durations of sitting, eating, and walking (P < 0.05). The interaction of age and treatment had a significant impact on the frequency of eating and walking and the duration of preening (P < 0.05). In conclusion, broiler chickens housed in DOUBLE pens did not exhibit a difference in behaviors compared to those in SINGLE pens, other than broilers in the DOUBLE pens performing leg extensions more often. While the first study indicated that having more space available per broiler chicken led to better walking ability, the second study showed the opposite to be true as those with more space had reduced walking ability. This indicates that changing the stocking density through manipulating space in the finisher phase may impact welfare, but further investigation is needed. Future research should first examine the effects of adding space in the finisher phase with 3 treatment groups. While the two discussed here would remain the same, the third group should start with broilers in a pen that is already the size of the DOUBLE pens and remains that way for the entire project. This will ensure that increasing space during the finisher period is beneficial rather than the additional space availability in general accounting for the differences in treatments. All treatment groups should also get fresh bedding with the pen increase to ensure the welfare measurement results are due to the changes in space availability rather than the provision of fresh litter.</p>

<p dir="ltr">This thesis explores the intricate mechanisms governing paracellular permeability, a process vital for maintaining homeostasis and barrier integrity in epithelial and endothelial tissues. Central to this exploration are tight junctions (TJs), multi-protein complexes that regulate substance movement between cells. The thesis begins with a comprehensive literature review synthesizing current research on how bacterial and viral proteins can enhance paracellular permeability or modulate TJs, highlighting their significance in both scientific and medical fields.</p><p dir="ltr">A focal point of the thesis is the detailed study of the <i>Listeria</i> adhesion protein (LAP), an epithelial TJ modulator (TJM). LAP’s interaction with the epithelial receptor, Hsp60, facilitates the translocation of <i>Listeria monocytogenes </i>across the epithelial barrier, presenting a novel approach for drug delivery. Addressing the limitations of current TJMs, such as poor bioavailability and toxic side effects, the thesis provides an in-depth analysis of LAP as an alternative biologics’ delivery vehicle. Utilizing a multidisciplinary research approach, the study reveals the cryo-EM structure of LAP at 2.9 Å resolution, elucidating its multimeric formation and interaction with Hsp60 through electrostatic forces, as supported by computational modeling.</p><p dir="ltr">The functional efficacy of LAP is further established through experiments demonstrating its capability to transport drug analogs across epithelial cell monolayers comparably to established TJMs. Moreover, <i>in vivo</i> studies using a mouse oral gavage model show that LAP significantly enhances the blood levels of peptide drugs without triggering inflammatory responses or harming tight junction architecture. This thesis ultimately positions the LAP-Hsp60 complex as a promising TJM candidate, offering an innovative means for enhancing oral drug delivery and maintaining epithelial barrier integrity.</p>

<p>  </p> <p>The research in this dissertation explored the impact of different sugar reducing agents [SRAs: sugars, sugar alcohols, oligosaccharides (OS), and polymers] on the thermal properties of starch (gelatinization, pasting, and retrogradation) and the baking performance of a model baked goods system (wire-cut cookies). The overconsumption of added sugar and underconsumption of dietary fiber have been linked to increased developmental risks for obesity and related diseases, including cardiovascular disease, diabetes, and colorectal cancer. Some SRAs, such as non-digestible oligosaccharides (OS), are considered soluble dietary fiber and could help offset the health detriments from excess sugar and low fiber intake, while also providing similar functionality (texture and structure) to that of sucrose in baked goods systems that rely on the control of phase and state changes in starch. The gelatinization temperature (Tgel) of wheat starch in the presence of SRA solutions at various concentrations (10% to 60% w/w) was measured using differential scanning calorimetry (DSC), and was best explained by SRA plasticization properties [solvent effective volume fraction (<em>feff,w</em>)], solution viscosity, and size (based on the previously proposed starch granule size limit of 1,000 g/mol). The paste viscosity parameters of starch in SRA solutions were measured with a routine rapid visco analyzer (RVA); and were increased in monosaccharide solutions and decreased in 6-carbon sugar alcohol and OS solutions as solution concentration was increased. Differences in starch paste response variables were explained by SRAs either promoting or restricting amylose leaching during heating. The recrystallization of amylopectin over time was promoted in monosaccharide solutions (glucose, fructose, allulose) and in many OS solutions, and was explained in terms of SRA hydrogen bonding interactions with water and/or starch chains. The appearance attributes of wire-cut cookies containing OS were similar to a sucrose control formulation; however, differences were found in cookie texture attributes which were linked to OS effects on solution viscosity and moisture retention during baking. Cookies made with allulose and erythritol were the least similar to the sucrose control across all quality attributes, and therefore these two SRAs would not be recommended as sugar replacers in low-moisture baked goods. The findings from this dissertation could be helpful to food researchers and product developers seeking to reduce or replace added sugars in starch-containing food systems with healthier alternatives.</p>

<p dir="ltr">This study explores the use of hand warmers to enhance hermetic storage. Hand warmers work similarly to conventional oxygen scavengers by consuming oxygen through oxidation. This research aimed to determine how effective hand warmers are in accelerating oxygen reduction and insect mortality in hermetic storage, hence preserving grain quality. The experiments conducted in hermetic containers showed that hand warmers rapidly reduce oxygen levels, achieving insect-lethal conditions much faster than conventional oxygen absorbers like Oxy-Sorb. Our results show that hand warmers brought oxygen levels down to below 5% within 24-48 h and kept them low for an extended period up to 240 h. This quick oxygen depletion led to high insect mortality, reduced oviposition, and inhibited progeny development. Additionally, hand warmers did not negatively impact seed moisture content or germination rates, demonstrating their effectiveness in maintaining grain quality during storage.</p>

<p dir="ltr">The following dissertation contains a series of articles from a diverse set of research experiences over my five years as a PhD student at Purdue University. Each of the following articles relay how my interdisciplinary studies in food safety, gender, and higher education contribute to a comprehensive understanding of international development in agriculture. After an introductory chapter, chapters two and three include systematic literature review articles on the state of food safety in Lao PDR and Cambodia. Each review discusses available knowledge and potential development opportunities surrounding food safety, a significant threat to public health, especially in low- and middle-income countries. Building upon the food safety literature, chapters four and five are based upon research aimed at reducing foodborne illnesses in Cambodia’s informal vegetable value chain. Toward this end, the chapters present two articles that study the lives of Cambodian women vegetable producers to inform future food safety engagement. The final three chapters are a collection of articles based on my experiences working with agricultural higher education in international development contexts. Chapters six and seven present two articles about the employability of Egyptian agriculture university graduates. Chapter eight includes my final research article and explores how a service learning-based study abroad in Romania encouraged agricultural engagement interest and skills in undergraduate agricultural students. Lastly, chapter nine concludes the dissertation with final remarks and reflections about how each discipline provided a different perspective to international development in agriculture, and the value of applying interdisciplinary approaches to complex challenges.</p>

<p dir="ltr">From farm to fork, every player in the food supply chain bears responsibility for ensuring food safety standards are met. Food safety educators are a key component in addressing knowledge and behavior gaps amongst the different players. Conducting a needs assessment allows educators to appropriately design a food safety education program for its target population. Three case studies are presented in this thesis, each investigating the food safety perceptions and needs of different target populations through a needs assessment. Each case study had two objectives: 1) identify food safety education needs for a specific target population; and 2) provide specific food safety education recommendations to address identified needs. The overall objective of this thesis was to uncover the food safety relationships between the different players in the food supply chain. The first case study (Ch. 2) examines consumers’ preferences for food safety through a national online survey. The study conclusively demonstrates consumers’ discernible preference for produce with food safety labels, however reflecting a willingness to pay only a small premium for such products. Indicating an increased price to consumer may not be an appropriate incentive in motivating farmers to adopt food safety practices. The second case study (Ch. 3) examined military veteran farmers’ on-farm food safety perceptions, knowledge, and behaviors through a national survey and in-person interviews. Military veteran farmers are aware of the importance of food safety; however, they reported risky on-farm food safety behaviors. Furthermore, military veteran farmers' unique needs were uncovered, which could help educators tailor resources for this niche farmer group. The third case study (Ch. 4) examined small- size produce drying processors’ food safety needs from the perspective of the inspector through interviews. The study demonstrated a need for clarity on the regulations and food safety standards for the small- size produce drying process. In summary, this thesis demonstrates the need for tailored food safety education interventions to meet the specific expectations of small-size and niche players in the food supply chain. Future work is recommended to continue exploring the food safety needs of niche players in the food supply chain and providing tailored food safety programs.</p>

<p dir="ltr">This dissertation discusses the effects of a sustainability facts label on organic selection, demand for plant-based meat alternatives, and the political polarization of beef expenditure.</p>