| 1. |
- Li, H. N., et al.
(författare)
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Secondary necrosis of apoptotic neutrophils induced by the human cathelicidin LL-37 is not proinflammatory to phagocytosing macrophages
- 2009
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Ingår i: J Leukoc Biol. - 1938-3673 .- 1938-3673. ; 86:4, s. 891-902
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Tidskriftsartikel (refereegranskat)abstract
- Cathelicidins are CHDP with essential roles in innate host defense but also more recently associated with the pathogenesis of certain chronic diseases. These peptides have microbicidal potential and the capacity to modulate innate immunity and inflammatory processes. PMN are key innate immune effector cells with pivotal roles in defense against infection. The appropriate regulation of PMN function, death, and clearance is critical to innate immunity, and dysregulation is implicated in disease pathogenesis. The efferocytosis of apoptotic PMN, in contrast to necrotic cells, is proposed to promote the resolution of inflammation. We demonstrate that the human cathelicidin LL-37 induced rapid secondary necrosis of apoptotic human PMN and identify an essential minimal region of LL-37 required for this activity. Using these LL-37-induced secondary necrotic PMN, we characterize the consequence for macrophage inflammatory responses. LL-37-induced secondary necrosis did not inhibit PMN ingestion by monocyte-derived macrophages and in contrast to expectation, was not proinflammatory. Furthermore, the anti-inflammatory effects of apoptotic PMN on activated macrophages were retained and even potentiated after LL-37-induced secondary necrosis. However, this process of secondary necrosis did induce the release of potentially harmful PMN granule contents. Thus, we suggest that LL-37 can be a potent inducer of PMN secondary necrosis during inflammation without promoting macrophage inflammation but may mediate host damage through PMN granule content release under chronic or dysregulated conditions.
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| 2. |
- Harrington, Richard, et al.
(författare)
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Ecosystem services and biodiversity conservation: concepts and a glossary
- 2010
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Ingår i: Biodiversity and Conservation. - : Springer Science and Business Media LLC. - 0960-3115 .- 1572-9710. ; 19:10, s. 2773-2790
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Tidskriftsartikel (refereegranskat)abstract
- The RUBICODE project draws on expertise from a range of disciplines to develop and integrate frameworks for assessing the impacts of environmental change on ecosystem service provision, and for rationalising biodiversity conservation in that light. With such diverse expertise and concepts involved, interested parties will not be familiar with all the key terminology. This paper defines the terms as used within the project and, where useful, discusses some reasoning behind the definitions. Terms are grouped by concept rather than being listed alphabetically.
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| 3. |
- Kommula, S. M., et al.
(författare)
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Effect of Long-Range Transported Fire Aerosols on Cloud Condensation Nuclei Concentrations and Cloud Properties at High Latitudes
- 2024
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 51:6
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Tidskriftsartikel (refereegranskat)abstract
- Active vegetation fires in south-eastern (SE) Europe resulted in a notable increase in the number concentration of aerosols and cloud condensation nuclei (CCN) particles at two high latitude locations—the SMEAR IV station in Kuopio, Finland, and the Zeppelin Observatory in Svalbard, high Arctic. During the fire episode aerosol hygroscopicity κ slightly increased at SMEAR IV and at the Zeppelin Observatory κ decreased. Despite increased κ in high CCN conditions at SMEAR IV, the aerosol activation diameter increased due to the decreased supersaturation with an increase in aerosol loading. In addition, at SMEAR IV during the fire episode, in situ measured cloud droplet number concentration (CDNC) increased by a factor of ∼7 as compared to non-fire periods which was in good agreement with the satellite observations (MODIS, Terra). Results from this study show the importance of SE European fires for cloud properties and radiative forcing in high latitudes.
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| 4. |
- Larsson, M., et al.
(författare)
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Activation of HIV-1 specific CD4 and CD8 T cells by human dendritic cells : Roles for cross-presentation and non-infectious HIV-1 virus
- 2002
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Ingår i: AIDS. - : Ovid Technologies (Wolters Kluwer Health). - 0269-9370 .- 1473-5571. ; 16:10, s. 1319-1329
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Tidskriftsartikel (refereegranskat)abstract
- Background: The CD4 T cells in mucosal subepithelia are the first cells to become infected during sexual transmission of HIV-1. Dendritic cells (DC) are located in the same area and are known to play a central role in antiviral immune responses. However, extensive viral replication, syncytia formation and cell death follows the interaction between T cells and DC previously exposed to HIV-1. Despite this, anti-HIV responses are generated that control viremia following acute infection.Objective: The anti-HIV-1 cellular immune responses observed may be activated by sources other than productively infected DC. HIV-1 induces apoptosis both in cells it infects and in bystander cells. Furthermore, retroviral replication typically generates a predominance of defective particles. We tested whether DC exposed to antigen from either of these sources could elicit anti-HIV specific immune responses.Design and methods: Apoptotic or necrotic monocytes infected with vaccinia virus vectors encoding HIV antigens, a cell line with integrated HIV-1 and apoptotic CD4 T cells pulsed with non-infectious or infectious HIV-1 virus were used as sources of antigens to assess cross presentation by DC. Furthermore, direct DC presentation of antigen from non-infectious and infectious HIV-1 was examined.Results: We find that dead cells expressing HIV-1 antigens as well as non-infectious HIV-1 particles can be acquired and processed by DC, leading to the activation, differentiation and expansion of viral antigen-specific CD4 and CD8 T cells from seropositive individuals.Conclusions: These sources of antigens may be critical for the generation and maintenance of anti-HIV-1 immunity by DC.
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| 5. |
- Luck, Gary W., et al.
(författare)
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Quantifying the Contribution of Organisms to the Provision of Ecosystem Services
- 2009
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Ingår i: BioScience. - : Oxford University Press (OUP). - 0006-3568 .- 1525-3244. ; 59:3, s. 223-235
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Tidskriftsartikel (refereegranskat)abstract
- Research on ecosystem services has grown rapidly over the last decade. Two conceptual frameworks have been published to guide ecological assessments of organisms that deliver services-the concepts of service-providing units (SPUs) and ecosystem service providers (ESPs). Here, we unite these frameworks and present an SPU-ESP continuum that offers a coherent conceptual approach for synthesizing the latest developments in ecosystem service research, and can direct future studies at all levels of organization. In particular, we show how the service-provider concept call be applied tit the population, functional group, and community levels, We strongly emphasize the need to identify and quantify the organisms and their characteristics (e.g., functional traits) that provide services, and to assess service provision relative to the demands of human beneficiaries. We use key examples from the literature to illustrate the new approach and to highlight gaps in knowledge, particularly in relation to the impact of species interactions and ecosystem dynamics on service provision.
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| 6. |
- Mishra, Suneeti, et al.
(författare)
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Rapid night-time nanoparticle growth in Delhi driven by biomass-burning emissions
- 2023
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 16:3, s. 224-230
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Tidskriftsartikel (refereegranskat)abstract
- Natural and anthropogenic biomass burning are among the major sources of particulate pollution worldwide that affects air quality, climate and human health. Delhi, one of the world’s most populated cities, experiences severe haze events caused by particulate pollution during winter, but the underlying pathways remain poorly understood. Here we observe intense and frequent nocturnal particle growth events during haze development in Delhi from measurements of aerosols and gases during January–February at the Indian Institute of Technology in Delhi. The particle growth events occur systematically despite the unfavourable condition for new-particle formation, including the lack of photochemical production of low-volatility vapours and considerable loss of vapours under extremely polluted conditions. We estimate that this process is responsible for 70% of the total particle-number concentration during haze. We identify that the condensation of primary organic vapours from biomass burning is the leading cause of the observed growth. The sharp decrease in night-time temperatures and rapid increase in biomass-burning emissions drive these primary organic vapours out of equilibrium, resulting in their condensation and the growth of nanoparticles into sizes relevant for haze formation. This high impact of primary biomass-burning emissions on night-time nanoparticle growth is unique compared with most urban locations globally, where low-volatility vapours formed through oxidation during the day drive particle growth and haze formation. As uncontrolled biomass burning for residential heating and cooking is rife in the Indo–Gangetic plain, we expect this growth mechanism to be a source of ultrafine particles, affecting the health of 5% of the world’s population and impacting the regional climate. Our work implies that regulating uncontrolled biomass-combustion emissions may help inhibit nocturnal haze formation and improve human health in India.
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