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| 2. |
- Svensson, Johannes, et al.
(författare)
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Three-Dimensional Integration of InAs Nanowires by Template-Assisted Selective Epitaxy on Tungsten
- 2023
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Ingår i: Nano Letters. - 1530-6984. ; 23:11, s. 4756-4761
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Tidskriftsartikel (refereegranskat)abstract
- 3D integration of III-V semiconductors with Si CMOS is highly attractive since it allows combining new functions such as photonic and analog devices with digital signal processing circuitry. Thus far, most 3D integration approaches have used epitaxial growth on Si, layer transfer by wafer bonding, or die-to-die packaging. Here we present low-temperature integration of InAs on W using Si3N4 template assisted selective area metal-organic vapor-phase epitaxy (MOVPE). Despite growth nucleation on polycrystalline W, we can obtain a high yield of single-crystalline InAs nanowires, as observed by transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). The nanowires exhibit a mobility of 690 cm2/(V s), a low-resistive, Ohmic electrical contact to the W film, and a resistivity which increases with diameter attributed to increased grain boundary scattering. These results demonstrate the feasibility for single-crystalline III-V back-end-of-line integration with a low thermal budget compatible with Si CMOS.
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| 3. |
- Tao, Feng, et al.
(författare)
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Microbial carbon use efficiency promotes global soil carbon storage
- 2023
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 618:7967, s. 981-985
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Tidskriftsartikel (refereegranskat)abstract
- Soils store more carbon than other terrestrial ecosystems. How soil organic carbon (SOC) forms and persists remains uncertain, which makes it challenging to understand how it will respond to climatic change. It has been suggested that soil microorganisms play an important role in SOC formation, preservation and loss. Although microorganisms affect the accumulation and loss of soil organic matter through many pathways, microbial carbon use efficiency (CUE) is an integrative metric that can capture the balance of these processes. Although CUE has the potential to act as a predictor of variation in SOC storage, the role of CUE in SOC persistence remains unresolved. Here we examine the relationship between CUE and the preservation of SOC, and interactions with climate, vegetation and edaphic properties, using a combination of global-scale datasets, a microbial-process explicit model, data assimilation, deep learning and meta-analysis. We find that CUE is at least four times as important as other evaluated factors, such as carbon input, decomposition or vertical transport, in determining SOC storage and its spatial variation across the globe. In addition, CUE shows a positive correlation with SOC content. Our findings point to microbial CUE as a major determinant of global SOC storage. Understanding the microbial processes underlying CUE and their environmental dependence may help the prediction of SOC feedback to a changing climate.
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| 4. |
- Conlon, Thomas M, et al.
(författare)
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Inhibition of LTβR signalling activates WNT-induced regeneration in lung
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 588:7836, s. 151-156
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Tidskriftsartikel (refereegranskat)abstract
- Lymphotoxin β-receptor (LTβR) signalling promotes lymphoid neogenesis and the development of tertiary lymphoid structures1,2, which are associated with severe chronic inflammatory diseases that span several organ systems3-6. How LTβR signalling drives chronic tissue damage particularly in the lung, the mechanism(s) that regulate this process, and whether LTβR blockade might be of therapeutic value have remained unclear. Here we demonstrate increased expression of LTβR ligands in adaptive and innate immune cells, enhanced non-canonical NF-κB signalling, and enriched LTβR target gene expression in lung epithelial cells from patients with smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke. Therapeutic inhibition of LTβR signalling in young and aged mice disrupted smoking-related inducible bronchus-associated lymphoid tissue, induced regeneration of lung tissue, and reverted airway fibrosis and systemic muscle wasting. Mechanistically, blockade of LTβR signalling dampened epithelial non-canonical activation of NF-κB, reduced TGFβ signalling in airways, and induced regeneration by preventing epithelial cell death and activating WNT/β-catenin signalling in alveolar epithelial progenitor cells. These findings suggest that inhibition of LTβR signalling represents a viable therapeutic option that combines prevention of tertiary lymphoid structures1 and inhibition of apoptosis with tissue-regenerative strategies.
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| 5. |
- Lehmann, Johannes, et al.
(författare)
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Persistence of soil organic carbon caused by functional complexity
- 2020
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 13, s. 529-534
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Tidskriftsartikel (refereegranskat)abstract
- Soil organic carbon management has the potential to aid climate change mitigation through drawdown of atmospheric carbon dioxide. To be effective, such management must account for processes influencing carbon storage and re-emission at different space and time scales. Achieving this requires a conceptual advance in our understanding to link carbon dynamics from the scales at which processes occur to the scales at which decisions are made. Here, we propose that soil carbon persistence can be understood through the lens of decomposers as a result of functional complexity derived from the interplay between spatial and temporal variation of molecular diversity and composition. For example, co-location alone can determine whether a molecule is decomposed, with rapid changes in moisture leading to transport of organic matter and constraining the fitness of the microbial community, while greater molecular diversity may increase the metabolic demand of, and thus potentially limit, decomposition. This conceptual shift accounts for emergent behaviour of the microbial community and would enable soil carbon changes to be predicted without invoking recalcitrant carbon forms that have not been observed experimentally. Functional complexity as a driver of soil carbon persistence suggests soil management should be based on constant care rather than one-time action to lock away carbon in soils. Dynamic interactions between chemical and biological controls govern the stability of soil organic carbon and drive complex, emergent patterns in soil carbon persistence.
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| 6. |
- Hestrin, Rachel, et al.
(författare)
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Synergies between mycorrhizal fungi and microbial communities increase plant nitrogen acquisition
- 2019
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen availability often restricts primary productivity in terrestrial ecosystems. Arbuscular mycorrhizal fungi are ubiquitous symbionts of terrestrial plants and can improve plant nitrogen acquisition, but have a limited ability to access organic nitrogen. Although other soil biota mineralize organic nitrogen into bioavailable forms, they may simultaneously compete for nitrogen, with unknown consequences for plant nutrition. Here, we show that synergies between the mycorrhizal fungus Rhizophagus irregularis and soil microbial communities have a highly non-additive effect on nitrogen acquisition by the model grass Brachypodium distachyon. These multipartite microbial synergies result in a doubling of the nitrogen that mycorrhizal plants acquire from organic matter and a tenfold increase in nitrogen acquisition compared to non-mycorrhizal plants grown in the absence of soil microbial communities. This previously unquantified multipartite relationship may contribute to more than 70 Tg of annually assimilated plant nitrogen, thereby playing a critical role in global nutrient cycling and ecosystem function.
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| 7. |
- Camenzind, Tessa, et al.
(författare)
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Arbuscular mycorrhizal fungal and soil microbial communities in African Dark Earths
- 2018
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Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 94:4
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Tidskriftsartikel (refereegranskat)abstract
- The socio-economic values of fertile and carbon-rich Dark Earth soils are well described from the Amazon region. Very recently, Dark Earth soils were also identified in tropical West Africa, with comparable beneficial soil properties and plant growth-promoting effects. The impact of this management technique on soil microbial communities, however, is less well understood, especially with respect to the ecologically relevant group of arbuscular mycorrhizal (AM) fungi. Thus, we tested the hypotheses that (1) improved soil quality in African Dark Earth (AfDE) will increase soil microbial biomass and shift community composition and (2) concurrently increased nutrient availability will negatively affect AM fungal communities. Microbial communities were distinct in AfDE in comparison to adjacent sites, with an increased fungal:bacterial ratio of 71%, a pattern mainly related to shifts in pH. AM fungal abundance and diversity, however, did not differ despite clearly increased soil fertility in AfDE, with 3.7 and 1.7 times greater extractable P and total N content, respectively. The absence of detrimental effects on AM fungi, often seen following applications of inorganic fertilizers, and the enhanced role of saprobic fungi relevant for mineralization and C sequestration support previous assertions of this management type as a sustainable alternative agricultural practice.
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| 8. |
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| 9. |
- Josko, Izabela, et al.
(författare)
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Effect of biochars, activated carbon and multiwalled carbon nanotubes on phytotoxicity of sediment contaminated by inorganic and organic pollutants
- 2013
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 60, s. 50-59
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Tidskriftsartikel (refereegranskat)abstract
- To reduce the risk related with the presence of contaminants in sediments, methods based on the use of adsorbents (mainly activated carbon) are applied. Adsorbents neutralise the contaminants by reducing their mobility, bioavailability and toxicity. The objective of this study was to determine the toxicity of sediment contaminated with organic compounds and heavy metals with and without the addition of selected adsorbents. In the study three carbonaceous materials (CM) potentially useful in remediation were applied: activated carbon (AC), biochars (BC1, BC2), and multi- walled carbon nanotubes (CNTs). The effect of the dose, particle diameter and time of contact between sediment and CM on the effectiveness of the detoxification were estimated. Ecotoxicological assessment was made based on the Phytotoxkit FTM test, using Lepidium sativum as the test plant. The materials tested reduced the negative effect of sediment on L. sativum. The highest effectiveness was achieved after the application of AC (70% reduction of seed germination inhibition, 27.5% reduction of root growth inhibition). The reduction of phytotoxicity of the sediment as a result of addition of BC1, BC2 and CNT varied within the range from 30 to 40% (reduction of seed germination inhibition) and from 17.7 to 28.9% (reduction of root growth inhibition). The reduction of sediment toxicity decreased with decreasing diameter of the biochars applied. Probably because of increasing fouling extension of the time of contact between CM and sediment had an unfavourable effect on the reduction of root growth inhibition in the case of all materials tested.
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| 10. |
- Hale, Sarah E., et al.
(författare)
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Quantifying the Total and Bioavailable Polycyclic Aromatic Hydrocarbons and Dioxins in Biochars
- 2012
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Ingår i: Environmental Science and Technology. - Washington, DC : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46:5, s. 2830-2838
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Tidskriftsartikel (refereegranskat)abstract
- Biochar soil amendment is advocated to mitigate climate change and improve soil fertility. A concern though, is that during biochar preparation PAHs and dioxins are likely formed. These contaminants can possibly be present in the biochar matrix and even bioavailable to exposed organisms. Here we quantify total and bioavailable PAHs and dioxins in a suite of over 50 biochars produced via slow pyrolysis between 250 and 900 degrees C, using various methods and biomass from tropical, boreal, and temperate areas. These slow pyrolysis biochars, which can be produced locally on farms with minimum resources, are also compared to biochar produced using the industrial methods of fast pyrolysis and gasification. Total concentrations were measured with a Soxhlet extraction and bioavailable concentrations were measured with polyoxymethylene passive samplers. Total PAH concentrations ranged from 0.07 mu g g(-1) to 3.27 mu g g(-1) for the slow pyrolysis biochars and were dependent on biomass source, pyrolysis temperature, and time. With increasing pyrolysis time and temperature, PAH concentrations generally decreased. These total concentrations were below existing environmental quality standards for concentrations of PAHs in soils. Total PAH concentrations in the fast pyrolysis and gasification biochar were 0.3 mu g g(-1) and 45 mu g g(-1), respectively, with maximum levels exceeding some quality standards. Concentrations of bioavailable PAHs in slow pyrolysis biochars ranged from 0.17 ng L-1 to 10.0 ng L-1 which is lower than concentrations reported for relatively clean urban sediments. The gasification produced biochar sample had the highest bioavailable concentration (162 +/- 71 ng L-1). Total dioxin concentrations were low (up to 92 mu g g(-1)) and bioavailable concentrations were below the analytical limit of detection. No clear pattern of how strongly PAHs were bound to different biochars was found based on the biochars' physicochemical properties.
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