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| 2. |
- Aguilera, Anabella, et al.
(författare)
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Cell death in Cyanobacteria : current understanding and recommendations for a consensus on its nomenclature
- 2021
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 12, s. 1-15
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Forskningsöversikt (refereegranskat)abstract
- Cyanobacteria are globally widespread photosynthetic prokaryotes and are major contributors to global biogeochemical cycles. One of the most critical processes determining cyanobacterial eco-physiology is cellular death. Evidence supports the existence of controlled cellular demise in cyanobacteria, and various forms of cell death have been described as a response to biotic and abiotic stresses. However, cell death research in this phylogenetic group is a relatively young field and understanding of the underlying mechanisms and molecular machinery underpinning this fundamental process remains largely elusive. Furthermore, no systematic classification of modes of cell death has yet been established for cyanobacteria. In this work, we analyzed the state of knowledge in the field of cyanobacterial cell death. Based on that, we propose unified criterion for the definition of accidental, regulated, and programmed forms of cell death in cyanobacteria based on molecular, biochemical, and morphologic aspects following the directions of Nomenclature Committee on Cell Death (NCCD). With this, we aim to provide a guide to standardize the nomenclature related to this topic in a precise and consistent manner, which will facilitate further ecological, evolutionary and applied research in the field of cyanobacterial cell death
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| 3. |
- Aguilera, Anabella, et al.
(författare)
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Do photosynthetic cells communicate with each other during cell death? From cyanobacteria to vascular plants
- 2022
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 73:22, s. 7219-7242
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Forskningsöversikt (refereegranskat)abstract
- As in metazoans, life in oxygenic photosynthetic organisms relies on the accurate regulation of cell death. During development and in response to the environment, photosynthetic cells activate and execute cell death pathways that culminate in the death of a specific group of cells, a process known as regulated cell death (RCD). RCD control is instrumental, as its misregulation can lead to growth penalties and even the death of the entire organism. Intracellular molecules released during cell demise may act as ‘survival’ or ‘death’ signals and control the propagation of cell death to surrounding cells, even in unicellular organisms. This review explores different signals involved in cell-cell communication and systemic signalling in photosynthetic organisms, in particular Ca2+, reactive oxygen species, lipid derivates, nitric oxide, and eATP. We discuss their possible mode-of-action as either ‘survival’ or ‘death’ molecules and their potential role in determining cell fate in neighbouring cells. By comparing the knowledge available across the taxonomic spectrum of this coherent phylogenetic group, from cyanobacteria to vascular plants, we aim at contributing to the identification of conserved mechanisms that control cell death propagation in oxygenic photosynthetic organisms
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| 4. |
- Aharonian, F., et al.
(författare)
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Simultaneous multiwavelength observations of the second exceptional gamma-ray flare of PKS2155-304 in July 2006
- 2009
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 502:3, s. 749-770
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Forskningsöversikt (refereegranskat)abstract
- Aims. The X-ray-TeV connection and the evolution of the emitting particle population is studied in high-energy peaked BL Lac objects, by obtaining spectral information in both bands on sub-hour timescales. Methods. Simultaneous observations with HESS, Chandra and the Bronberg optical observatory were performed on the BL Lac object PKS 2155-304 in the night of July 29-30 2006, when the source underwent a major gamma-ray outburst during its high-activity state of Summer 2006. This event took place about 44 h after the other major outburst of the night of July 27-28, which is known for its ultrafast variability. An unprecedented 6 to 8 h of simultaneous, uninterrupted coverage was achieved, with spectra and light curves measured down to 7 and 2 min timescales, respectively. Results. The source exhibited one major flare along the night, at high energies. The gamma-ray flux reached a maximum of similar to 11 times the Crab flux (>400 GeV), with rise/decay timescales of similar to 1 h, plus a few smaller-amplitude flares superimposed on the decaying phase. The emission in the X-ray and VHE gamma-ray bands is strongly correlated, with no evidence of lags. The spectra also evolve with similar patterns, and are always soft ( photon index G > 2), indicating no strong shift of the peaks in the spectral energy distribution towards higher energies. Only at the flare maximum is there evidence that the gamma-ray peak is inside the observed passband, at similar to 400-600 GeV. The VHE spectrum shows a curvature that is variable with time and stronger at higher fluxes. The huge VHE variations (similar to 22x) are only accompanied by small-amplitude X-ray and optical variations (factor 2 and 15% respectively). The source has shown for the first time in a high-energy peaked BL Lac object a large Compton dominance (L(C)/L(S) similar to 10) - rapidly evolving - and a cubic relation between VHE and X-ray flux variations, during a decaying phase. These results challenge the common scenarios for the TeV-blazar emission.
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| 5. |
- Ahlstrom, Christina A., et al.
(författare)
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Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 764, s. 1-10
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Forskningsöversikt (refereegranskat)abstract
- Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal telemetry to describe host movement patterns, and a novel modeling approach to combine information from these diverse data streams to investigate the acquisition and long-distance dispersal of antimicrobial resistant bacteria by landfill-foraging gulls. Our results provide evidence that gulls acquire antimicrobial resistant bacteria from anthropogenic sources, which they may subsequently disperse across and between continents via migratory movements. Furthermore, we introduce a flexible modeling framework to estimate the relative dispersal risk of antimicrobial resistant bacteria in western North America and adjacent areas within East Asia, which may be adapted to provide information on the risk of dissemination of other organisms and pathogens maintained by wildlife through space and time. Published by Elsevier B.V.
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| 6. |
- Akner, Gunnar, 1953-
(författare)
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Klinisk nutrition har svag ställning i vårdsystemet
- 2015
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Ingår i: Äldre i centrum. - Stockholm : Stiftelsen Stockholms läns Äldrecentrum. - 1653-3585. ; :1, s. 15-17
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- »Många studier genom åren har visat att inte ens en så enkel och lätt bestämd variabel som kroppsvikt registreras och analyseras tydligt över tid.«Man försöker trycka in kvalitet i klinisk nutrition i ett vårdsystem som inte är förberett på saken. Detta i en situation med a) brist på infrastruktur i vården, b) brist på utbildning/träning i klinisk nutrition hos personalen och c) avsaknad av en medicinsk specialitet för klinisk nutrition. Det skriver professor Gunnar Akner i en debatterande översiktsartikel.
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| 7. |
- Albeverio, Sergio, et al.
(författare)
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p-Adic valued quantization
- 2009
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Ingår i: P-Adic Numbers, Ultrametric Analysis, and Applications. - Berlin : Springer. - 2070-0466 .- 2070-0474. ; 1:2, s. 91-104
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Forskningsöversikt (refereegranskat)abstract
- This review covers an important domain of p-adic mathematical physics — quantum mechanics with p-adic valued wave functions. We start with basic mathematical constructions of this quantum model: Hilbert spaces over quadratic extensions of the field of p-adic numbers ℚ p , operators — symmetric, unitary, isometric, one-parameter groups of unitary isometric operators, the p-adic version of Schrödinger’s quantization, representation of canonical commutation relations in Heisenberg andWeyl forms, spectral properties of the operator of p-adic coordinate.We also present postulates of p-adic valued quantization. Here observables as well as probabilities take values in ℚ p . A physical interpretation of p-adic quantities is provided through approximation by rational numbers.
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| 8. |
- Algaba, Juan-Carlos, et al.
(författare)
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Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
- 2021
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
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Forskningsöversikt (refereegranskat)abstract
- In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
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| 9. |
- Algurén, Beatrix, et al.
(författare)
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A scoping review and mapping exercise comparing the content of patient-reported outcome measures (PROMs) across heart disease-specific scales
- 2020
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Ingår i: Journal of Patient-Reported Outcomes. - : Springer. - 2509-8020. ; 4:1
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: Over the past decade, the importance of person-centered care has led to increased interest in patient-reported outcome measures (PROMs). In cardiovascular care, selecting an appropriate PROM for clinical use or research is challenging because multimorbidity is often common in patients. The aim was therefore to provide an overview of heart-disease specific PROMs and to compare the content of those outcomes using a bio-psycho-social framework of health.METHODS: A scoping review of heart disease-specific PROMs, including arrhythmia/atrial fibrillation, congenital heart disease, heart failure, ischemic heart disease, and valve diseases was conducted in PubMed (January 2018). All items contained in the disease-specific PROMs were mapped to WHO's International Classification of Functioning, Disability and Health (ICF) according to standardized linking rules.RESULTS: A total of 34 PROMs (heart diseases in general n = 5; cardiac arrhythmia n = 6; heart failure n = 14; ischemic heart disease n = 9) and 147 ICF categories were identified. ICF categories covered Body functions (n = 61), Activities & Participation (n = 69), and Environmental factors (n = 17). Most items were about experienced problems of Body functions and less often about patients' daily activities, and most PROMs were specifically developed for heart failure and no PROM were identified for valve disease or congenital heart disease.CONCLUSIONS: Our results motivate and provide information to develop comprehensive PROMs that consider activity and participation by patients with various types of heart disease.
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| 10. |
- Ali, Sharafat, Associate Professor, 1976-, et al.
(författare)
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Effect of composition on the thermal properties and structure of M-Al-Si-O-N glasses, M = Na, Mg, Ca
- 2024
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Ingår i: Progress in Solid State Chemistry. - : Elsevier. - 0079-6786 .- 1873-1643. ; 74
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Forskningsöversikt (refereegranskat)abstract
- The primary objective of this study is to explore the relationship between the composition, structure, and thermal characteristics of M-Al-Si-O-N glasses, with M representing sodium (Na), magnesium (Mg), or calcium (Ca). The glasses were prepared by melting in a quartz crucible at 1650 degrees C and AlN precursor (powder) was utilized as a nitrogen source. The measured thermal properties studied were glass transition temperature (Tg), crystallization temperature (Tc), glass stability, viscosity, and thermal expansion coefficient (alpha). The findings indicate that increasing the aluminum content leads to higher glass transition, crystallization temperatures, and viscosities. In contrast, fragility values increase with the Al contents, while modifier elements and silicon content influence thermal expansion coefficient values. FTIR analysis revealed that in all glasses, the dominant IR bands are attributed to the presence of Q2 and Q3 silicate units. The effect of Al is observed as a progressive polymerization of the silicate network resulting from the glass-forming role of Al2O3. In most samples, the Q4 silicate mode was also observed, strongly related to the high Al content. Overall, the study shows that the complexity of composition-property correlations where the structural changes affect the properties of Mg/Ca-based oxynitride glasses has potential implications for their use in various technological fields.
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