112 research outputs found

    Sustainability assessment of bioenergy from a global perspective: a review

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    Bioenergy, as a renewable energy resource, is expected to see significant development in the future. However, a key issue that will affect this trend is sustainability of bioenergy. There have been many studies on this topic, but mainly focusing on only one- or two-dimensions of the issue, and also with much of the literature directed at studies of European regions. To help understand the wider scope of bioenergy sustainability, this paper reviews a broad range of current research on the topic, and places the literature into a multi-dimensional framework covering the economic, environmental and ecological, social, and land-related aspects of bioenergy sustainability, as well as a geographical analysis of the areas for which the studies have been carried out. The review indicates that it is hard to draw an overall conclusion on the sustainability of bioenergy because of limited studies or contradictory results in some aspects. In addition, this review shows that crop-based bioenergy and forest bioenergy are seen as the main sources of bioenergy, and that most studies discuss the final utilization of bioenergy as being for electricity generation. Finally, research directions for future study are suggested, based on the literature reviewed here

    Integrated nontargeted and targeted metabolomics analyses amino acids metabolism in infantile hemangioma

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    Infantile hemangioma (IH) is the most common benign tumor in children. However, the exact pathogenesis of IH remains unclear. Integrated nontargeted and targeted metabolic analyses were performed to obtain insight into the possible pathogenic mechanism of IH. The results of nontargeted metabolic analysis showed that 216 and 128 differential metabolites (DMs) were identified between hemangioma-derived endothelial cells (HemECs) and HUVECs in positive-ion and negative-ion models, respectively. In both models, these DMs were predominantly enriched in pathways related to amino acid metabolism, including aminoacyl-tRNA biosynthesis and arginine and proline metabolism. Then, targeted metabolic analysis of amino acids was further performed to further clarify HemEC metabolism. A total of 22 amino acid metabolites were identified, among which only 16 metabolites, including glutamine, arginine and asparagine, were significantly differentially expressed between HemECs and HUVECs. These significant amino acids were significantly enriched in 10 metabolic pathways, including ‘alanine, aspartate and glutamate metabolism’, ‘arginine biosynthesis’, ‘arginine and proline metabolism’, and ‘glycine, serine and threonine metabolism’. The results of our study revealed that amino acid metabolism is involved in IH. Key differential amino acid metabolites, including glutamine, asparagine and arginine, may play an important role in regulating HemEC metabolism

    Controlling n-Type Molecular Doping via Regiochemistry and Polarity of Pendant Groups on Low Band Gap Donor-Acceptor Copolymers

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    We demonstrate the impact of the type and position of pendant groups on the n-doping of low-band gap donor-acceptor (D-A) copolymers. Polar glycol ether groups simultaneously increase the electron affinities of D-A copolymers and improve the host/dopant miscibility compared to nonpolar alkyl groups, improving the doping efficiency by a factor of over 40. The bulk mobility of the doped films increases with the fraction of polar groups, leading to a best conductivity of 0.08 S cm(-1) and power factor (PF) of 0.24 mu W m(-1) K-2 in the doped copolymer with the polar pendant groups on both the D and A moieties. We used spatially resolved absorption spectroscopy to relate commensurate morphological changes to the dispersion of dopants and to the relative local doping efficiency, demonstrating a direct relationship between the morphology of the polymer phase, the solvation of the molecular dopant, and the electrical properties of doped films. Our work offers fundamental new insights into the influence of the physical properties of pendant chains on the molecular doping process, which should be generalizable to any molecularly doped polymer films

    Quorum sensing: cell-to-cell communication in Saccharomyces cerevisiae

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    Quorum sensing (QS) is one of the most well-studied cell-to-cell communication mechanisms in microorganisms. This intercellular communication process in Saccharomyces cerevisiae began to attract more and more attention for researchers since 2006, and phenylethanol, tryptophol, and tyrosol have been proven to be the main quorum sensing molecules (QSMs) of S. cerevisiae. In this paper, the research history and hotspots of QS in S. cerevisiae are reviewed, in particular, the QS system of S. cerevisiae is introduced from the aspects of regulation mechanism of QSMs synthesis, influencing factors of QSMs production, and response mechanism of QSMs. Finally, the employment of QS in adaptation to stress, fermentation products increasing, and food preservation in S. cerevisiae was reviewed. This review will be useful for investigating the microbial interactions of S. cerevisiae, will be helpful for the fermentation process in which yeast participates, and will provide an important reference for future research on S. cerevisiae QS

    Biogenic Synthesis and Spatial Distribution of Endogenous Phytohormones and Ginsenosides Provide Insights on Their Intrinsic Relevance in Panax ginseng

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    Ginseng, the root and rhizome of Panax ginseng C. A. Mey., is a well-known and valuable traditional Chinese medicine. The pharmacological activities of ginseng are mainly attributed to the presence of ginsenosides, which are considered to be critical biomarkers for evaluating ginseng quality. The biosynthesis of triterpenes, which serve defensive functions in plants, is regulated by endogenous phytohormones that play key roles in growth and defense of plant populations. However, the role of major hormones that are closely related to secondary metabolism pathways in P. ginseng is poorly understood. To gain insight into their potential correlation, we performed a spatial synthesis analysis and studied the distribution of endogenous phytohormones and ginsenosides in different tissue regions of the entire P. ginseng plant. Gibberellins are growth hormones that accumulate in the fiber root. In contrast, abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA), which are considered stress hormones, were predominantly found in the leaf and leaf peduncle. We observed a tissue-specific distribution of phytohormones consistent with the expression of genes involved in hormone biosynthesis that influenced ginsenoside synthesis and distribution. The aim of this study was to investigate the role of different endogenous phytohormones on triterpene metabolites in ginseng innate immunity

    Securing lithium supply for a cleaner energy consumption pathway: A systems thinking on supply disruptions

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    To mitigate climate change and realize the transition towards a cleaner consumption pattern, the development of EVs needs to be ensured as it is one of the major solutions to the fossil fuel-related problems human beings face today. Lithium, as a critical material to EV cells, is seen as a strategic resource in many countries. Given the fact that the global lithium distribution is quite uneven, securing lithium supply for the development of EVs is essential for the world to phase out fossil fuels consumption in the transport sector. The supply risks of lithium can be observed in many aspects, ranging from lithium production to geopolitics. In this paper, the author combines qualitative and quantitative analysis in order to overarchingly reflect the global supply disruptions of lithium. In the qualitative section, the concept of systems theory is applied, supported by the connection circle, the stock-flow model, and the panarchy model; in the quantitative section, the author uses the combination of Herfindahl-Hirschman Index (HHI) and Worldwide Governance Indicators (WGI) to measure the extent of supply disruptions in a certain year. The quantitative section serves as a good supplement to the qualitative analysis. The qualitative results indicate that lithium mining and processing plays the key role in the whole lithium supply chain. It can be affected by the factors in the larger global context such as global political environment and the demand for lithium, as well as the social, ecological and technical components in the smaller scale that provides a physical environment for lithium production. The quantitative results show that the global supply disruptions of lithium are significant in 2019, mainly due to the high level of supply concentration. The author suggests that the governments of major lithium producer countries might organize panel discussions regularly to ensure the stable and non-centric supply of lithium to the global market. The rich production countries may also offer technical support to the less developed lithium holders to help the latter overcome the difficulties brought by the increasing cost of mining.

    Securing lithium supply for a cleaner energy consumption pathway: A systems thinking on supply disruptions

    Get PDF
    To mitigate climate change and realize the transition towards a cleaner consumption pattern, the development of EVs needs to be ensured as it is one of the major solutions to the fossil fuel-related problems human beings face today. Lithium, as a critical material to EV cells, is seen as a strategic resource in many countries. Given the fact that the global lithium distribution is quite uneven, securing lithium supply for the development of EVs is essential for the world to phase out fossil fuels consumption in the transport sector. The supply risks of lithium can be observed in many aspects, ranging from lithium production to geopolitics. In this paper, the author combines qualitative and quantitative analysis in order to overarchingly reflect the global supply disruptions of lithium. In the qualitative section, the concept of systems theory is applied, supported by the connection circle, the stock-flow model, and the panarchy model; in the quantitative section, the author uses the combination of Herfindahl-Hirschman Index (HHI) and Worldwide Governance Indicators (WGI) to measure the extent of supply disruptions in a certain year. The quantitative section serves as a good supplement to the qualitative analysis. The qualitative results indicate that lithium mining and processing plays the key role in the whole lithium supply chain. It can be affected by the factors in the larger global context such as global political environment and the demand for lithium, as well as the social, ecological and technical components in the smaller scale that provides a physical environment for lithium production. The quantitative results show that the global supply disruptions of lithium are significant in 2019, mainly due to the high level of supply concentration. The author suggests that the governments of major lithium producer countries might organize panel discussions regularly to ensure the stable and non-centric supply of lithium to the global market. The rich production countries may also offer technical support to the less developed lithium holders to help the latter overcome the difficulties brought by the increasing cost of mining.
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