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  • 1
    Language: English
    In: Advanced materials (Deerfield Beach, Fla.), 19 July 2011, Vol.23(27), pp.3018-21
    Description: Direct laser writing and subsequent electroless silver plating is introduced as a high‐quality fabrication method for three‐dimensional plasmonic nanostructures. With this method, we fabricate the first three‐dimensional bichiral plasmonic crystals, which exhibit a large difference in transmittance of left‐handed and right‐handed circularly polarized light in the mid‐infrared spectral region between 3 and 5 μm. Our structure has a high degree of isotropy, showing only a weak dependence of the transmittance on the angle of incidence.
    Keywords: Lasers ; Silver -- Chemistry
    ISSN: 09359648
    E-ISSN: 1521-4095
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  • 2
    In: Ecology, May 2011, Vol.92(5), pp.1052-1062
    Description: Lignin is a main component of plant litter. Its degradation is thought to be critical for litter decomposition rates and the build‐up of soil organic matter. We studied the relationships between lignin degradation and the production of dissolved organic carbon (DOC) and of CO during litter decomposition. Needle or leaf litter of five species (Norway spruce, Scots pine, mountain ash, European beech, sycamore maple) and of different decomposition stage (freshly fallen and up to 27 months of field exposure) was incubated in the laboratory for two years. Lignin degradation was followed with the CuO method. Strong lignin degradation occurred during the first 200 incubation days, as revealed by decreasing yields of lignin‐derived phenols. Thereafter lignin degradation leveled off. This pattern was similar for fresh and decomposed litter, and it stands in contrast to the common view of limited lignin degradation in fresh litter. Dissolved organic carbon and CO also peaked in the first period of the incubation but were not interrelated. In the later phase of incubation, CO production was positively correlated with DOC amounts, suggesting that bioavailable, soluble compounds became a limiting factor for CO production. Lignin degradation occurred only when CO production was high, and not limited by bioavailable carbon. Thus carbon availability was the most important control on lignin degradation. In turn, lignin degradation could not explain differences in DOC and CO production over the study period. Our results challenge the traditional view regarding the fate and role of lignin during litter decomposition. Lignin degradation is controlled by the availability of easily decomposable carbon sources. Consequently, it occurs particularly in the initial phase of litter decomposition and is hampered at later stages if easily decomposable resources decline.
    Keywords: C Availability ; Dissolved Organic Matter ; Lignin ; Plant Litter Decomposition ; Respiration Rates
    ISSN: 0012-9658
    E-ISSN: 1939-9170
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  • 3
    In: Global Change Biology, January 2018, Vol.24(1), pp.e183-e189
    Description: Current climate and land‐use changes affect regional and global cycles of silicon (Si), with yet uncertain consequences for ecosystems. The key role of Si in marine ecology by controlling algae growth is well recognized but research on terrestrial ecosystems neglected Si since not considered an essential plant nutrient. However, grasses and various other plants accumulate large amounts of Si, and recently it has been hypothesized that incorporation of Si as a structural plant component may substitute for the energetically more expensive biosynthesis of lignin. Herein, we provide evidence supporting this hypothesis. We demonstrate that in straw of rice () deriving from a large geographic gradient across South‐East Asia, the Si concentrations (ranging from 1.6% to 10.7%) are negatively related to the concentrations of carbon (31.3% to 42.5%) and lignin‐derived phenols (32 to 102 mg/g carbon). Less lignin may explain results of previous studies that Si‐rich straw decomposes faster. Hence, Si seems a significant but hardly recognized factor in organic carbon cycling through grasslands and other ecosystems dominated by Si‐accumulating plants. The key role of silicon in marine ecology by controlling algae growth is well recognized but research on terrestrial ecosystems neglected Si since not considered an essential plant nutrient. However, many plants accumulate large amounts of Si, and recently it has been hypothesized that incorporation of Si as a structural component may substitute for the energetically more expensive biosynthesis of lignin. Herein, we provide evidence supporting this hypothesis. We demonstrate that in rice straw deriving from a large geographic gradient across South‐East Asia, the Si concentrations are negatively related to the concentrations of carbon and lignin‐derived phenols. Our data offer an explanation for previous findings of faster decomposition of Si‐rich rice straw as lignin regulates plant litter decomposition rates. Hence, Si seems a significant but hardly recognized factor in carbon cycling through ecosystems dominated by grass species and/or other Si‐accumulating plants.
    Keywords: Carbon Cycle ; Lignin ; Litter Decomposition ; Rice ; Silicon ; Structural Plant Components
    ISSN: 1354-1013
    E-ISSN: 1365-2486
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  • 4
    Language: English
    In: Advanced Materials, 07/19/2011, Vol.23(27), pp.2995-2995
    ISSN: Advanced Materials
    E-ISSN: 09359648
    Source: Wiley (via CrossRef)
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  • 5
    Language: English
    In: Cancer Research, 04/15/2013, Vol.73(8 Supplement), pp.2788-2788
    ISSN: 0008-5472
    E-ISSN: 1538-7445
    Source: CrossRef
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  • 6
    Language: English
    In: Soil biology & biochemistry, 2013, Vol.67, pp.133-139
    Description: Dissolved organic matter (DOM) plays a fundamental role for many soil processes. For instance, production, transport, and retention of DOM control properties and long-term storage of organic matter in mineral soils. Production of water-soluble compounds during the decomposition of plant litter is a major process providing DOM in soils. Herein, we examine processes causing the commonly observed increase in contribution of aromatic compounds to WSOM during litter decomposition, and unravel the relationship between lignin degradation and the production of aromatic WSOM. We analysed amounts and composition of water-soluble organic matter (WSOM) produced during 27 months of decomposition of leaves and needles (ash, beech, maple, spruce, pine). The contribution of aromatic compounds to WSOM, as indicated by the specific UV absorbance of WSOM, remained constant or increased during decomposition. However, the contribution of lignin-derived compounds to the total phenolic products of ¹³C-labelled tetramethylammonium hydroxide (¹³C-TMAH) thermochemolysis increased strongly (by 〉114%) within 27 months of decomposition. Simultaneous changes in contents of lignin phenols in solid litter residues (cupric oxide method as well as ¹³C-TMAH thermochemolysis) were comparably small (−39% to +21% within 27 months). This suggests that the increasing contribution of lignin-derived compounds to WSOM during decomposition does not reflect compositional changes of solid litter residues, but rather the course of decomposition processes. In the light of recently published findings, these processes include: (i) progressive oxidative alteration of lignin that results in increasing solubility of lignin, (ii) preferential degradation of soluble, non-lignin compounds that limits their contribution to WSOM during later phases of decomposition. ; p. 133-139.
    Keywords: Phenols ; Fagus ; Lignin ; Dissolved Organic Matter ; Mineral Soils ; Picea ; Solubility ; Leaves ; Plant Litter ; Absorbance
    ISSN: 0038-0717
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
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  • 7
    Language: English
    In: Soil Biology and Biochemistry, 2013, Vol.67, pp.133-139
    Description: Dissolved organic matter (DOM) plays a fundamental role for many soil processes. For instance, production, transport, and retention of DOM control properties and long-term storage of organic matter in mineral soils. Production of water-soluble compounds during the decomposition of plant litter is a major process providing DOM in soils. Herein, we examine processes causing the commonly observed increase in contribution of aromatic compounds to WSOM during litter decomposition, and unravel the relationship between lignin degradation and the production of aromatic WSOM. We analysed amounts and composition of water-soluble organic matter (WSOM) produced during 27 months of decomposition of leaves and needles (ash, beech, maple, spruce, pine). The contribution of aromatic compounds to WSOM, as indicated by the specific UV absorbance of WSOM, remained constant or increased during decomposition. However, the contribution of lignin-derived compounds to the total phenolic products of 13C-labelled tetramethylammonium hydroxide (13C-TMAH) thermochemolysis increased strongly (by 〉114%) within 27 months of decomposition. Simultaneous changes in contents of lignin phenols in solid litter residues (cupric oxide method as well as 13C-TMAH thermochemolysis) were comparably small (−39% to +21% within 27 months). This suggests that the increasing contribution of lignin-derived compounds to WSOM during decomposition does not reflect compositional changes of solid litter residues, but rather the course of decomposition processes. In the light of recently published findings, these processes include: (i) progressive oxidative alteration of lignin that results in increasing solubility of lignin, (ii) preferential degradation of soluble, non-lignin compounds that limits their contribution to WSOM during later phases of decomposition.
    ISSN: 0038-0717
    Source: NARCIS (National Academic Research and Collaborations Information System)
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  • 8
    Language: English
    In: Soil Biology and Biochemistry, December 2013, Vol.67, pp.133-139
    Description: Dissolved organic matter (DOM) plays a fundamental role for many soil processes. For instance, production, transport, and retention of DOM control properties and long-term storage of organic matter in mineral soils. Production of water-soluble compounds during the decomposition of plant litter is a major process providing DOM in soils. Herein, we examine processes causing the commonly observed increase in contribution of aromatic compounds to WSOM during litter decomposition, and unravel the relationship between lignin degradation and the production of aromatic WSOM. We analysed amounts and composition of water-soluble organic matter (WSOM) produced during 27 months of decomposition of leaves and needles (ash, beech, maple, spruce, pine). The contribution of aromatic compounds to WSOM, as indicated by the specific UV absorbance of WSOM, remained constant or increased during decomposition. However, the contribution of lignin-derived compounds to the total phenolic products of C-labelled tetramethylammonium hydroxide ( C-TMAH thermochemolysis increased strongly (by 〉114%) within 27 months of decomposition. Simultaneous changes in contents of lignin phenols in solid litter residues (cupric oxide method as well as C-TMAH thermochemolysis) were comparably small (−39% to +21% within 27 months). This suggests that the increasing contribution of lignin-derived compounds to WSOM during decomposition does not reflect compositional changes of solid litter residues, but rather the course of decomposition processes. In the light of recently published findings, these processes include: (i) progressive oxidative alteration of lignin that results in increasing solubility of lignin, (ii) preferential degradation of soluble, non-lignin compounds that limits their contribution to WSOM during later phases of decomposition.
    Keywords: Dissolved Organic Matter ; Water Soluble Organic Matter ; Litter Decomposition ; Lignin Degradation ; 13c-Tmah Thermochemolysis ; Litter Bag Experiment ; Agriculture ; Chemistry
    ISSN: 0038-0717
    E-ISSN: 1879-3428
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  • 9
    Language: English
    In: Journal of current Chinese affairs, 2014, Vol.43(2), pp.65-85
    Description: In the era of the "scientific development concept" of the Hu/Wen leadership, agents of knowledge transfer that eventually translates into policy comprise not only think tanks for policy formulation in central-state institutions but also researchers in universities supporting policy implementation at local levels. Well-established patterns of local scientific advisory frame collaborative fieldwork in Sino-Western scientific projects on local governance. However, there is a gap between our active integration into these patterns during fieldwork and our ability to clarify them as resources, reconstruct the selection of research topics and contextualize the research results within our academic discourses. Analysing site-finding, data collection, aggregation and dissemination of a research project with Chinese public health researchers on rural health service reform in Xinjiang between 2005 and 2010, I argue that fieldwork and the role performed as a scientific advisor for the political principal is the localized and daily interface where politics crosses into science.
    Keywords: China ; Xinjiang ; Collaborative Research ; Health Care ; Scientific Advice
    ISSN: 1868-1026
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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  • 10
    Language: English
    In: Journal of Current Chinese Affairs, 06/2014, Vol.43(2), pp.7-12
    ISSN: 1868-1026
    E-ISSN: 1868-4874
    Source: Sage Publications (via CrossRef)
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