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Design and analysis of information systems for individual health and well-being
(2024) Bonenberger, Lukas; Gimpel, Henner
Information systems (IS) are ubiquitous in today’s world. Initially rooted in the business context, IS research within personal settings is steadily gaining momentum. An essential factor contributing to this phenomenon is the acknowledgment that IS and their design can improve the lives of individuals. Individuals encounter various challenges that adversely affect their health and well-being. However, IS present avenues to address some of these issues. Prominent examples of such challenges that prior research has identified as susceptible to mitigation through IS include stress, grief, home resource conservation, information technology (IT)-mediated interruptions, and social media harm. All these challenges negatively affect individuals’ health and well-being. IS are potent tools owing to their ubiquity and technological capabilities. Their designs shape their objectives and functionalities, which are crucial for addressing challenges and fostering individual health and well-being.
The transition of IS research from business to more personal spheres has been conceptualized into a framework for the digitalization of the individual (DOTI [1]). The DOTI framework encompasses the digitalization of individuals across two dimensions. First, it delineates the different roles of individuals that IS research can explore, including their roles as employees, social beings, and customers. Second, the framework encompasses the research angles of IS design, individuals’ behavior, and the consequences of their digitalization. This dissertation aligns with the DOTI framework, focusing on developing and analyzing IS designs tailored to individuals in various roles to foster their health and well-being.
The aim of this dissertation is twofold. First, it seeks to gain a comprehensive understanding of how IS can address the abovementioned challenges, which negatively impact individual health and well-being. Second, this dissertation aims to develop IS design knowledge and analyze IS design to establish a foundation for such knowledge development to mitigate challenges and foster individual health and well-being. This dissertation uses qualitative and quantitative research methods, including literature review, interviews, surveys, experiments, and field studies. Several methodological approaches are integrated into higher-level design science research. Further, one study adopts a mixed-methods approach, whereas another is fully quantitative.
This dissertation is divided into two parts. Part A aims to develop design knowledge for IS to foster individual health and well-being, while considering individuals in the role as themselves according to the DOTI framework. Chapter 2 describes the design of mobile stress assessment systems that detect individuals’ stress levels to enable subsequent coping efforts. It improves the understanding of how mobile systems can better support individuals in coping with stress, and presents theoretical design knowledge, five prototypes, and a structured literature review. Chapter 3 introduces design knowledge for more empathetic recommender systems on social media sites to enhance users’ well-being. It broadens the understanding of social media harm in the context of social media recommender systems by presenting a conceptual framework, meta-requirements, and design principles. Chapter 4 expands on these results and presents design knowledge for sensitive social media recommender systems. This design knowledge advances Chapter 3 by incorporating specific design features and evaluating user appraisals by using the Kano customer satisfaction model.
Part B of this dissertation focuses on considering individuals’ specific roles according to the DOTI framework in IS design aimed at fostering their health and well-being. Chapter 5 considers individuals as employees. It develops design knowledge for neuro-adaptive flow support systems to promote flow experiences and reduce IT-mediated interruptions in the workplace, with the aim of enhancing well-being and productivity. The chapter presents a neuro-adaptive interruption management mechanism. Chapter 6 investigates the effects of social norm messages as social media design elements in encouraging users to express sympathy toward online mourners, thereby enhancing their well-being. It considers individuals in specific roles as social beings. The chapter elucidates the design characteristics that contribute to the effectiveness of social norm messages in this domain. Chapter 7 explores the effects of the decision-making latitude of agentic IS artifacts on individuals’ psychological well-being and environmental friendliness perception in smart homes. Therefore, it considers individuals in their specific customer roles. The chapter provides insights into agentic IS artifact design regarding functional adaptivity, using the challenge of home resource conservation as an example.
In summary, this dissertation advances design knowledge and offers insights into IS design aimed at mitigating the challenges that adversely affect individuals’ health and well-being, thereby fostering these outcomes. This enriches the existing literature on IS design and investigation of these challenges, providing practical insights for effective mitigation efforts. Moreover, the research activities included in this dissertation contribute to promoting responsible digitalization.
Effects of a two-factorial dynamic storage system on apple fruit metabolism, quality attributes, disorder incidences and biochemical properties
(2024) Büchele, Felix; Vögele, Ralf; Kittemann, Dominikus
Dynamic Controlled Atmosphere (DCA) technologies are designed to monitor the metabolism of fruit as a function of time and the oxygen partial pressure (pO2) in the storage atmosphere. By identifying signals sent by the fruit in response to low oxygen stress, this concept allows defining the lowest oxygen level tolerated by the fruit material and the specific and transient pO2, which is proposed to slow down the aerobic respiration of the fruit to a minimum and accordingly the ripening-related loss of fruit quality. This work examines a novel storage technology for pome fruit referred to as DCA-CD+, which can be considered the first generation of a two-factorial dynamic storage system. DCA-CD+ aims to define both a transient optimum pO2 and storage temperature in real-time, based on monitoring the carbon dioxide (CO2) production rate of the stored product. The CO2-release
rate is proposed as a dependable indicator of low oxygen stress and an accurate depiction of the metabolic intensity of the fruit in response to temperature variations. The idea behind dynamic temperature adjustments is based on the assumption, that increased storage temperatures can reduce the energy usage of the refrigeration systems during long-term storage substantially, while also mitigating oxidative stress in the fruit, thus contributing to reducing the occurrence of storage disorders. The extremely low pO2 levels established in the storage atmosphere are suggested to counteract the ripening-inducing effects of this dynamic temperature approach. The assessment of DCA-CD+ in this work is based on a comparison to other postharvest conditions such as cold storage (RA) or static controlled atmosphere (CA). Furthermore, the interactions between storage atmosphere, temperature, and applications of the ethylene-inhibitor product 1-methylcyclopropene (1-MCP) are investigated. The conducted biochemical analyses highlight that apples stored under DCA-CD+ undergo repeated periods of hypoxia. Fruit adapt to the energy crisis induced by low oxygen stress by increasing their glycolytic flux, which is coupled to the activation of the fermentative pathway. Importantly, none of the examined apple cultivars in any of the experimental seasons exceeded critical thresholds for volatile fermentative products acetaldehyde (AA) and ethanol (EtOH), which could potentially be associated with the development of off-flavors or internal disorder symptoms. Consequently, the atmospheric conditions implemented did not result in any fruit damage associated with low oxygen stress in any of the tested scenarios. These findings suggest that DCA-CD+, specifically the use of carbon dioxide as an input value, is effective in identifying low oxygen stress in stored fruit and defining the pO2 for optimum quality conservation. pO2 setpoint calculation by the DCA-CD+ algorithm showed an interaction effect with the respective storage temperatures. Furthermore, the sensitivity of the stored fruit to temperature variation was found to be cultivar-dependent and transient during the storage period. Depending on the stored apple cultivar and season, DCA-CD+ calculated temperature setpoints reaching up to 3°C to 4°C, from the baseline temperature of 1°C. Temperature peaks were generally followed by a significant decrease in the calculated temperature setpoints, as an increased CO2 production rate signaled an intensifying fruit metabolism due to elevated storage temperature. The analysis of quality-defining parameters and disorder symptoms support the conclusion that DCA-CD+ allows for dynamic temperature adjustments without accelerating fruit ripening and the associated loss of quality. Preliminary findings indicate that this approach can reduce the energy usage of the cooling system in commercial storage rooms, without requiring cost-intensive additional installation of technology or renovations of room structural components.
Lower pO2 setpoints were calculated at higher temperatures, suggesting that increasing the storage temperature can contribute to alleviating low oxygen stress in apples. Improved conservation of fruit quality attributes and a reduction in storage disorder incidences of DCA-CD+ in comparison to CA could be demonstrated in some instances, contingent on experimental season and apple cultivar. These benefits presumably become more pronounced with extended storage durations exceeding eight months. Ultimately, it can be argued that the complementary and interactive effects of dynamic temperature and oxygen in DCA-CD+ with 1-MCP application
provide the highest potential for fruit quality conservation, limiting storage disorder, and reducing cooling-related energy usage. DCA-CD+ was demonstrated to potentially counteract detrimental effects of 1-MCP applications, e.g. an increased risk of carbon dioxide injuries. This work aimed to contribute to understanding the mechanisms behind the interference of the established temperature and atmospheric conditions in the DCA-CD+ system with the volatile aroma profile of apples. It was demonstrated that the synthesis capacity of volatile organic compounds (VOC) is primarily suppressed on a principal substrate level, and less in the later conversion of aldehydes to alcohols and esters. The pathways for the synthesis of linear volatiles originating from fatty acids were determined more responsive to low oxygen environments, in comparison to the pathways of branched volatiles derived from amino acids. Further insights were gained into the physiological mechanisms underlying the activation of the fermentative pathway, suggesting it functions as an adaptation mechanism not exclusively linked to low oxygen stress. Moreover, efforts were made to establish a connection between ripening and disorder-related modifications in cell structural components and associated alterations in the volatile profile, primarily highlighting the role of the lipoxygenase pathway. Statistical classification demonstrated that the repeated induction of low oxygen stress in DCA-CD+ storage resulted in a distinct volatile profile and a higher association with aroma defining compounds compared to CA storage. The observed increased EtOH accumulation is discussed to mitigate the ripening-inducing effects of the hormone ethylene, while also providing additional substrate for the synthesis of ethyl esters. Preliminary findings of this work indicate that storage temperatures can play a role in the aroma development of stored apples, even when low pO2 conditions are established. In summary, this study created a comprehensive documentation of the commercial viability of two-factorial dynamic storage systems for pome fruit and provided insights into the metabolomic responses of apples to extremely low oxygen levels, particularly in interaction with dynamic storage temperature adjustments.
Physiological, molecular, and epigenetic aspects of early transient nitrogen deprivation recovery in maize
(2024) Hernandez Pridybailo, Andres; Ludewig, Uwe
Maize is a widely cultivated crop and a primary food source for humans and livestock. Along with its substantial contribution to biomass for fuel production, maize is the most produced cereal globally. However, despite its prevalence, improving nitrogen (N) use efficiency in maize presents ongoing challenges. Understanding how maize plants utilize nitrogen is crucial for identifying traits that could aid breeders in addressing this efficiency gap. When plants experience transient stress and return to previous conditions, a recovery phase is initiated, acclimating the plants and potentially enhancing their responses to subsequent stress events. This mild or transient stress is termed "eustress," and its intentional manipulation is referred to as "crop priming." Crop priming, extensively studied in the context of drought, was explored in our previous research, which revealed that nitrogen supplementation during recovery from early transient water deficits enhances priming effects. This highlights the pivotal role of N in priming and that impaired N supply might negatively affect any acclimation to future stresses. Notably, there is limited literature on transient N deprivation, with most studies focusing on plant responses under conditions of maintained N deficiency.
Furthermore, epigenetic regulation of plant mineral nutritional responses via DNA methylation has been reported, like many aspects of plant development that are regulated by such mechanism. Epigenetics is the study of phenotypic changes that can be inherited through mitosis or meiosis, which cannot be explained by changes in the DNA sequence. DNA methylation is the covalent modification of cytosines by the addition of a methyl group, which, depending on its location in the genome, can affect genomic stability and gene expression. Previous results have revealed that N deficiency modifies the methylome of maize roots, hypomethylating transposable elements in a nutrient-specific way. Weak correlations between DNA methylation and gene expression were observed, but a deeper insight into how this covalent modification of cytosines is related to plant mineral nutrition is lacking. DNA methylation patterns are heritable in a sort of “epigenetic memory” and may arise after an environmental stimulus. Here, the role of DNA methylation and its relationship with physiological responses during transient N deprivation were studied.
The Fast-Flowering Mini-Maize inbred line A (FFMM-A) was chosen for this study because it can be easily grown hydroponically under controlled conditions. Maize ear leaves recovering from initial nitrogen deprivation (without water limitation) exhibited tissue-specific differences in rapidly dividing meristematic and mature photosynthetically active tissues. Through a series of experiments, a 60 h N deprivation period at the V1 stage was established as a nutritional stress that allowed plants to show mild N deprivation symptoms from which the plants fully recovered. Kinematic analysis of the recovering ear leaf revealed a slight decrease in leaf blade length due to reduced leaf meristem size and leaf number, resulting in a reduced cell production rate. Interestingly, the leaf elongation rate (LER) was maintained, causing a higher specific leaf area, which affected the leaf blade structure. Transcriptomic analysis of the cell division and maturation zones of the recovering ear leaf showed altered gene expression related to cell cycle, lipid metabolism, and secondary metabolism, including phytohormone regulation. Notably, cell cycle-related proteins are also involved in DNA repair and may be involved in somatic memory effects. If plants that had been exposed to early transient N-deficiency stress were later subjected to a second N-deprivation stress at the V5 stage, physiological measurements showed that early N deprivation affected upper leaf chlorophyll accumulation during late N-deprivation recovery. These findings suggest that early N deprivation has long-term effects, especially in dividing tissues, from which young and mature tissues are produced by replication.
Furthermore, I identified that the loss of DNA methylation makes maize plants more susceptible to early N deprivation. Loss-of-function zmet2 allele was used in this study. Examination of the methylome of the zmet2 and zmet5 mutants provided insights into the relationship between DNA methylation patterns, nitrogen responses, and the expression of developmentally regulated genes in the leaf. These alleles correspond to CHROMOMETHYLASE3-like maintenance methyltransferase genes, and their mutation causes generalized genome hypomethylation, mostly in the CHG and CHH contexts. After a 96 h N deprivation period at the V1 stage, the zmet2 mutants failed to modify their root-to-shoot ratio and to maintain the LER, with respect to the isogenic B73 line. Moreover, machine learning identified interesting clusters according to their expression patterns from the leaf transcriptome of the dividing and maturation zones of FFMM-A plants. Reanalysis of publicly available datasets from B73 seedling leaf methylation patterns and those of the zmet2 and zmet5 mutants was used to compare the expression patterns of the gene clusters, their methylation patterns, and selected genome features. Interestingly, the methylation pattern of the gene body was highly correlated with the level of expression in the dividing zone of the developing ear leaf. Collectively, mutants in the methylation maintenance pathway, rather than being susceptible to N deprivation, failed to develop symptoms of recovery from such stress, which might be related to the regulation of N metabolism-related genes by DNA methylation. Additionally, the closely related gene expression pattern in the dividing zone and intron non-CpG methylation suggests an intimate role of maintenance of DNA methylation in N nutrition.