Modelling the system dynamics of household food, water, and energy nexus effects

The food-energy-water nexus (F-E-W) serves as a crucial resource for the sustainability of households, while the efficiency of resource use largely depends on our understanding and management of the nexus including all three factors. Limited research has been conducted on this topic thus far because of the increasing complexity of home technologies and data availability. This study develops an evidence-based system dynamics model for assessing the synergy and trade-offs of the household F-E-W. By applying the system dynamics (SD) methodology, the FEW consumption and generation originating from home appliances were modelled and simulated. The model was applied to an eco-house in Tokyo, and its efficacy was validated with one-year hour-based observations of a home energy management system (HEMS). The findings revealed that water-related and food-related energy use accounted for approximately 55% of the total energy use. In addition, water-related energy use showed high uncertainty, suggesting a management potential of approximately 24% for reduction, and was significantly correlated with household carbon emissions. Moreover, this result verified that the effective management of household energy consumption requires the adept manipulation of the diverse array of energy sources employed for air and water heating, while HEMSs could play a key role in implementation.

Metabolic-epigenetic nexus in regulation of stem cell fate

Stem cell fate determination is one of the central questions in stem cell biology, and although its regulation has been studied at genomic and proteomic levels, a variety of biological activities in cells occur at the metabolic level. Metabolomics studies have established the metabolome during stem cell differentiation and have revealed the role of metabolites in stem cell fate determination. While metabolism is considered to play a biological regulatory role as an energy source, recent studies have suggested the nexus between metabolism and epigenetics because several metabolites function as cofactors and substrates in epigenetic mechanisms, including histone modification, DNA methylation, and microRNAs. Additionally, the epigenetic modification is sensitive to the dynamic metabolites and consequently leads to changes in transcription. The nexus between metabolism and epigenetics proposes a novel stem cell-based therapeutic strategy through manipulating metabolites. In the present review, we summarize the possible nexus between metabolic and epigenetic regulation in stem cell fate determination, and discuss the potential preventive and therapeutic strategies via targeting metabolites.