This thesis examines the impacts and challenges of water use of electric power system. This thesis found that there are large differences in water use of electricity technologies, with hydropower... Show moreThis thesis examines the impacts and challenges of water use of electric power system. This thesis found that there are large differences in water use of electricity technologies, with hydropower and thermal power being two large water users. Water is used for power production and then virtually transmitted via power transmission networks. From this angle, regional water stress can be influenced by power transmission across regions. The power system has further impacts on freshwater biodiversity because of its freshwater consumption and thermal emissions. Power system faces challenges when its water demand cannot be met. Carbon capture and storage is an important approach to reducing carbon emissions of power plants, while it requires additional water resources and could exacerbate the vulnerability of power system to water stress. It is necessary to deepen the analyses of the links between energy and water systems and incorporate the results into future energy and water management. Show less
There is a vast genomic resource for enzymes active on carbohydrates. Lagging far behind, however, are functional chemical tools for the rapid characterization of carbohydrate-active enzymes.... Show moreThere is a vast genomic resource for enzymes active on carbohydrates. Lagging far behind, however, are functional chemical tools for the rapid characterization of carbohydrate-active enzymes. Activity-based probes (ABPs) offer one chemical solution to these issues with ABPs based upon cyclophellitol epoxide and aziridine covalent and irreversible inhibitors representing a potent and widespread approach. Such inhibitors for enzymes active on polysaccharides are potentially limited by the requirement for several glycosidic bonds, themselves substrates for the enzyme targets. Here, it is shown that non-hydrolysable trisaccharide can be synthesized and applied even to enzymes with challenging subsite requirements. It was found that incorporation of carbasugar moieties, which was accomplished by cuprate-assisted regioselective trans-diaxial epoxide opening of carba-mannal synthesised for this purpose, yields inactivators that act as powerful activity-based inhibitors for alpha-1,6 endo-mannanases. 3-D structures at 1.35-1.47 angstrom resolutions confirm the design rationale and binding to the enzymatic nucleophile. Carbasugar oligosaccharide cyclophellitols offer a powerful new approach for the design of robust endoglycosidase inhibitors, while the synthesis procedures presented here should allow adaptation towards activity-based endoglycosidase probes as well as configurational isosteres targeting other endoglycosidase families. Show less
Jin, Y.; Behrens, P.A.; Tukker, A.; Scherer, L. 2021
Understanding the water use of power production is an important step to both a sustainable energy transition and an improved understanding of water conservation measures. However, there are large... Show moreUnderstanding the water use of power production is an important step to both a sustainable energy transition and an improved understanding of water conservation measures. However, there are large differences across the literature that currently present barriers to decision making. Here, the compiled inventory of the blue water use of power production from existing studies allowed to uncover the characteristics of water use and to investigate current uncertainties. The results show that photovoltaics, wind power, and run-of-the-river hydropower consume relatively little water, whereas reservoir hydropower and woody and herbaceous biomass can have an extremely large water footprint. The water consumption of power production can differ greatly across countries due to different geographic conditions. Only a few studies provided the values for the influencing factors of water use, such as the capacity factor. Values that are reported came mainly from assumptions and other literature rather than direct measurement. Omitting a life cycle stage may lead to significant underestimations. Water scarcity is attracting more attention, but the few existing results are not useable for a regional comparison due to data gaps and inconsistent measurements. In the future, a clear and detailed definition of the water footprint and system boundary of power production is essential to improving comparisons and energy systems modelling. Show less
Wang, D.; Saleh, N.B.; Sun, W.; Park, C.M.; Shen, C.; Aich, N.; ... ; Su, C. 2019
Nanotechnology has unprecedentedly revolutionized human societies over the past decades and will continue to advance our broad societal goals in the coming decades. The research, development, and... Show moreNanotechnology has unprecedentedly revolutionized human societies over the past decades and will continue to advance our broad societal goals in the coming decades. The research, development, and particularly the application of engineered nanomaterials have shifted the focus from “less efficient” single-component nanomaterials toward “superior-performance”, next-generation multifunctional nanohybrids. Carbon nanomaterials (e.g., carbon nanotubes, graphene family nanomaterials, carbon dots, and graphitic carbon nitride) and metal/metal oxide nanoparticles (e.g., Ag, Au, CdS, Cu2O, MoS2, TiO2, and ZnO) combinations are the most commonly pursued nanohybrids (carbon–metal nanohybrids; CMNHs), which exhibit appealing properties and promising multifunctionalities for addressing multiple complex challenges faced by humanity at the critical energy–water–environment (EWE) nexus. In this frontier review, we first highlight the altered and newly emerging properties (e.g., electronic and optical attributes, particle size, shape, morphology, crystallinity, dimensionality, carbon/metal ratio, and hybridization mode) of CMNHs that are distinct from those of their parent component materials. We then illustrate how these important newly emerging properties and functions of CMNHs direct their performances at the EWE nexus including energy harvesting (e.g., H2O splitting and CO2 conversion), water treatment (e.g., contaminant removal and membrane technology), and environmental sensing and in situ nanoremediation. This review concludes with identifications of critical knowledge gaps and future research directions for maximizing the benefits of next-generation multifunctional CMNHs at the EWE nexus and beyond. Show less
Humans express at least two distinct β-glucuronidase enzymes that are involved in disease: exo-acting β-glucuronidase (GUSB), whose deficiency gives rise to mucopolysaccharidosis type VII, and endo... Show moreHumans express at least two distinct β-glucuronidase enzymes that are involved in disease: exo-acting β-glucuronidase (GUSB), whose deficiency gives rise to mucopolysaccharidosis type VII, and endo-acting heparanase (HPSE), whose overexpression is implicated in inflammation and cancers. The medical importance of these enzymes necessitates reliable methods to assay their activities in tissues. Herein, we present a set of β-glucuronidase-specific activity-based probes (ABPs) that allow rapid and quantitative visualization of GUSB and HPSE in biological samples, providing a powerful tool for dissecting their activities in normal and disease states. Unexpectedly, we find that the supposedly inactive HPSE proenzyme proHPSE is also labeled by our ABPs, leading to surprising insights regarding structural relationships between proHPSE, mature HPSE, and their bacterial homologs. Our results demonstrate the application of β-glucuronidase ABPs in tracking pathologically relevant enzymes and provide a case study of how ABP-driven approaches can lead to discovery of unanticipated structural and biochemical functionality. Show less
The hierarchical organization of properly sized blood vessels ensures the correct distribution of blood to all organs of the body, and is controlled via haemodynamic cues. In current concepts, an... Show moreThe hierarchical organization of properly sized blood vessels ensures the correct distribution of blood to all organs of the body, and is controlled via haemodynamic cues. In current concepts, an endothelium-dependent shear stress set point causes blood vessel enlargement in response to higher flow rates, while lower flow would lead to blood vessel narrowing, thereby establishing homeostasis. We show that during zebrafish embryonic development increases in flow, after an initial expansion of blood vessel diameters, eventually lead to vessel contraction. This is mediated via endothelial cell shape changes. We identify the transforming growth factor beta co-receptor endoglin as an important player in this process. Endoglin mutant cells and blood vessels continue to enlarge in response to flow increases, thus exacerbating pre-existing embryonic arterial-venous shunts. Together, our data suggest that cell shape changes in response to biophysical cues act as an underlying principle allowing for the ordered patterning of tubular organs. Show less
Covalent, mechanism-based inhibitors of glycosidases are valuable probe molecules for visualising enzyme activities in complex systems. We here describe the chemoenzymatic synthesis of 6-phospho... Show moreCovalent, mechanism-based inhibitors of glycosidases are valuable probe molecules for visualising enzyme activities in complex systems. We here describe the chemoenzymatic synthesis of 6-phospho-cyclophellitol and evaluate its behaviour as a mechanism-based inactivator of the Streptococcus pyogenes 6-phospho-β-glucosidase from CAZy family GH1. We further present the three-dimensional structure of the inactivated enzyme, which reveals the constellation of active site residues responsible for the enzyme's specificity and confirms the covalent nature of the inactivation. This article is protected by copyright. All rights reserved. Show less
