| 1. |
- Baxter, Charles J, et al.
(författare)
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The metabolic response of heterotrophic Arabidopsis cells to oxidative stress
- 2007
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Ingår i: Plant Physiology. - Rockville, USA : American Society of Plant Biologists. - 0032-0889 .- 1532-2548. ; 143:1, s. 312-25
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Tidskriftsartikel (refereegranskat)abstract
- To cope with oxidative stress, the metabolic network of plant cells must be reconfigured either to bypass damaged enzymes or to support adaptive responses. To characterize the dynamics of metabolic change during oxidative stress, heterotrophic Arabidopsis (Arabidopsis thaliana) cells were treated with menadione and changes in metabolite abundance and (13)C-labeling kinetics were quantified in a time series of samples taken over a 6 h period. Oxidative stress had a profound effect on the central metabolic pathways with extensive metabolic inhibition radiating from the tricarboxylic acid cycle and including large sectors of amino acid metabolism. Sequential accumulation of metabolites in specific pathways indicated a subsequent backing up of glycolysis and a diversion of carbon into the oxidative pentose phosphate pathway. Microarray analysis revealed a coordinated transcriptomic response that represents an emergency coping strategy allowing the cell to survive the metabolic hiatus. Rather than attempt to replace inhibited enzymes, transcripts encoding these enzymes are in fact down-regulated while an antioxidant defense response is mounted. In addition, a major switch from anabolic to catabolic metabolism is signaled. Metabolism is also reconfigured to bypass damaged steps (e.g. induction of an external NADH dehydrogenase of the mitochondrial respiratory chain). The overall metabolic response of Arabidopsis cells to oxidative stress is remarkably similar to the superoxide and hydrogen peroxide stimulons of bacteria and yeast (Saccharomyces cerevisiae), suggesting that the stress regulatory and signaling pathways of plants and microbes may share common elements.
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| 2. |
- Geng, Huifang, et al.
(författare)
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Controlled synthesis of highly stable lead-free bismuth halide perovskite nanocrystals : tructures and photophysics
- 2023
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Ingår i: SCIENCE CHINA Materials. - : Springer Science and Business Media LLC. - 2095-8226 .- 2199-4501. ; 66:5, s. 2079-2089
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Tidskriftsartikel (refereegranskat)abstract
- Recently, cesium bismuth halide perovskites have emerged as potential substitutes to their counterparts, cesium lead halide perovskites, owing to their low toxicity. However, the photophysics of cesium-bismuth halides nanocrystals (NCs) have not yet been fully rationalized because their structures remain highly debated. The ultraviolet-visible (UV-vis) absorption along with other photophysical properties such as the nature and lifetime of the excited states vary considerably across the previous reports. Here, we successfully synthesize pure Cs3BiBr6 and Cs3Bi2Br9 NCs via a modified hot-injection method, where the structure can be easily controlled by tuning the reaction temperature. The UV-vis absorption spectrum of the pure Cs3Bi2Br9 NCs features two characteristic peaks originating from the absorption of the first exciton and second exciton, respectively, which ultimately clarifies the debate in the previous reports. Using femtosecond transient absorption spectroscopy, we systematically investigate the excited state dynamics of the Cs3Bi2Br9 NCs and reveal that the photoexcited carriers undergo a self-trapping process within 3 ps after excitation. More intriguingly, the Cs3Bi2Br9 NCs prepared by this method show much better photostability than those prepared by the ligand-assisted reprecipitation process. Photodetectors based on these Cs3Bi2Br9 NCs show a sensitive light response, demonstrating the definite potential for breakthrough optoelectronic applications. [Figure not available: see fulltext.].
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| 3. |
- Kang, Ying, et al.
(författare)
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Weak Bonds Joint Effects Catalyze the Cleavage of Strong C−C Bond of Lignin‐Inspired Compounds and Lignin in Air by Ionic Liquids
- 2020
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Ingår i: ChemSusChem. - : John Wiley & Sons. - 1864-5631 .- 1864-564X. ; 13:22, s. 5945-5953
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Tidskriftsartikel (refereegranskat)abstract
- Oxidation of lignin to value‐added aromatics through selective C−C bond cleavage via metal‐free and mild strategies is promising but challenging. It was discovered that the cations of ionic liquids (ILs) could effectively catalyze this kind of strong bond cleavage by forming multiple weak hydrogen bonds, enabling the reaction conducted in air at temperature lower than 373 K without metal‐containing catalysts. The cation [CPMim]+ (1‐propylronitrile‐3‐methylimidazolium) afforded the highest efficiency in C−C bond cleavage, in which high yields (>90 %) of oxidative products were achieved. [CPMim]+ could form three ipsilateral hydrogen bonds with the oxygen atom of C=O and ether bonds at both sides of the C−C bond. The weak bonds joint effects could promote adjacent C−H bond cleave to form free radicals and thereby catalyze the fragmentation of the strong C−C. This work opens up an eco‐friendly and energy‐efficient route for direct valorization of lignin by enhancing IL properties via tuning the cation.
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| 4. |
- Kantarelis, Efthymios, et al.
(författare)
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Sustainable Valorization of Bamboo via High-Temperature Steam Pyrolysis for Energy Production and Added Value Materials
- 2010
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 24, s. 6142-6150
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Tidskriftsartikel (refereegranskat)abstract
- Bamboo is an abundant plant in many Asian countries and especially in China, it has an extremely rapid growing rate, and It can be considered as a sustainable wood resource In this paper a comparative study of pyrolysis of bamboo in the presence of high temperature steam and an inert atmosphere (N-2) as well as characterization of products has been conducted Evaluation of experimental results showed that faster devolatilization can be achieved in the presence of high-temperature steam Furthermore, the gas composition indicates interaction of steam with vapors and solid species even at low temperatures Analysis of the obtained liquid after steam pyrolysis at 797 K revealed that the H/C and O/C ratios in the liquid are 1 54 and 0 16, respectively The characteristics of the products indicate possible exploitation of derived char as an activated carbon precursor, a reducing agent in metallurgical processes, or a solid fuel for gasification and combustion processes The composition of the liquid fraction suggests further exploitation as a liquid fuel and/or chemical feedstock
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| 5. |
- Liu, Xing, et al.
(författare)
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Preparation of RGO and CNT Composite Thin Film Electrode for Flexible Energy Storage Devices
- 2023
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Ingår i: 2022 10th International Symposium on Next Generation Electronics, ISNE 2022. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Recently, miniaturized systems with multiple functionalities, such as such as flexibility, self-powering and sensing capability are urgently desired for the practical applications. In this work, we reported the fabrication of novel reduced graphene oxide and carbon nanotube based composite electrode on the flexible polyimide substrate and explored its physical and electrochemical properties. The proposed composite electrode shows superior properties, such as high flexibility, high surface area, low inner resistance, as well as a high specific capacitance of 208.7 mF/cm2, and energy density of 5.33 mWh/cm2, indicating its great potential in the integrated supercapacitor and sensor applications.
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