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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Cai, Xuesong, et al.
(författare)
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Empirical Low-Altitude Air-to-Ground Spatial Channel Characterization for Cellular Networks Connectivity
- 2021
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Ingår i: IEEE Journal on Selected Areas in Communications. - 0733-8716. ; 39:10, s. 2975-2991
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Tidskriftsartikel (refereegranskat)abstract
- Cellular-connected unmanned aerial vehicles (UAVs) have recently attracted a surge of interest in both academia and industry. Understanding the air-to-ground (A2G) propagation channels is essential to enable reliable and/or high-throughput communications for UAVs and protect the ground user equipments (UEs). In this contribution, a recently conducted measurement campaign for the A2G channels is introduced. A uniform circular array (UCA) with 16 antenna elements was employed to collect the downlink signals of two different Long Term Evolution (LTE) networks, at the heights of 0-40m in three different, namely rural, urban and industrial scenarios. The channel impulse responses (CIRs) have been extracted from the received data, and the spatial, including angular, parameters of the multipath components in individual channels were estimated according to a high-resolution-parameter-estimation (HRPE) principle. Based on the HRPE results, clusters of multipath components were further identified. Finally, comprehensive spatial channel characteristics were investigated in the composite and cluster levels at different heights in the three scenarios.
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| 6. |
- Normand, Philippe, et al.
(författare)
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Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography.
- 2007
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051. ; 17:1, s. 7-15
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Tidskriftsartikel (refereegranskat)abstract
- Soil bacteria that also form mutualistic symbioses in plants encounter two major levels of selection. One occurs during adaptation to and survival in soil, and the other occurs in concert with host plant speciation and adaptation. Actinobacteria from the genus Frankia are facultative symbionts that form N2-fixing root nodules on diverse and globally distributed angiosperms in the "actinorhizal" symbioses. Three closely related clades of Frankia sp. strains are recognized; members of each clade infect a subset of plants from among eight angiosperm families. We sequenced the genomes from three strains; their sizes varied from 5.43 Mbp for a narrow host range strain (Frankia sp. strain HFPCcI3) to 7.50 Mbp for a medium host range strain (Frankia alni strain ACN14a) to 9.04 Mbp for a broad host range strain (Frankia sp. strain EAN1pec.) This size divergence is the largest yet reported for such closely related soil bacteria (97.8%–98.9% identity of 16S rRNA genes). The extent of gene deletion, duplication, and acquisition is in concert with the biogeographic history of the symbioses and host plant speciation. Host plant isolation favored genome contraction, whereas host plant diversification favored genome expansion. The results support the idea that major genome expansions as well as reductions can occur in facultative symbiotic soil bacteria as they respond to new environments in the context of their symbioses.
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| 7. |
- Santos, Catarina L, et al.
(författare)
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Modulation of Frankia alni ACN14a oxidative stress response: activity, expression and phylogeny of catalases
- 2007
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 130, s. 454-463
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Tidskriftsartikel (refereegranskat)abstract
- The finding that an oxidative burst was a general phenomenon in the response of hosts challenged by various symbiotic or pathogenic microbes has stimulated increasing interest in investigating the enzymology of antioxidant protection in bacteria. The question of whether the antioxidant mechanisms have been a decisive evolutionary driving force for the nitrogen-fixing microsymbiont Frankia spp. is still open. In this study, Frankia alni strain ACN14a, which is a mid-range infective strain, was used as a model to explore the basal oxidative stress response in terms of enzymatic activity, relative expression and phylogeny. Non-denaturing polyacrylamide gels stained for catalatic activity revealed the presence of two monofunctional catalases KatA and KatB (EC number 1.11.1.6), which activity was shown to increase when the cells were challenged with the oxidants H2O2 and methyl viologen. Real-time RT-PCR targeting the two genes showed a consistent increase in the number of transcripts when the RNA was extracted from oxidative stress-induced cells. Comparison between the expression and the activity data suggests that posttranscriptional mechanisms might be involved in the regulation of catalases in F. alni. Furthermore, upstream of katA, a fur gene coding for a ferric uptake regulator was found, forming a gene pair that functionally resembles the conserved actinobacterial synton fur–katG, which contains a gene coding for a catalase–peroxidase. Phylogenetic analysis of the F. alni fur–katA synton suggests that this genomic organization was the result of genome reshuffling events.
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| 8. |
- Tavares, Fernando, et al.
(författare)
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Identification and expression studies of a catalase and a bifunctional catalase-peroxidase in Frankia strain R43
- 2003
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Ingår i: Plant and Soil. - : Kluwer Academic Publishers. - 0032-079X .- 1573-5036. ; 254:1, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- A monofunctional catalase and a bifunctional catalase-peroxidase were revealed by activity staining of non-denaturing PAGE in Frankia strain R43. Both enzymes were shown to be cytoplasmatic, growth regulated and expressed mainly during the stationary growth phase. Nevertheless, low levels of constitutive expression could also be detected during the early stages of growth. Immunoblot analyses using a polyclonal antibody raised against a catalase-peroxidase purified from Streptomyces reticuli showed a band of 83.2 kDa, with the same growth dependent pattern as obtained by the non-denaturing PAGE analyses. Induction studies revealed that both enzymes were strongly induced by raising the intracellular concentration of H2O2 with paraquat, but not with exogenous H2O2. In addition, no acquisition of tolerance to exogenous H2O2 was observed whatever the pretreatment of the inocula, i.e. despite the expression level of both hydroperoxidases.
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| 9. |
- Tavares, Fernando, et al.
(författare)
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Reactive oxygen species in legume and actinorhizal nitrogen-fixing symbioses: the microsymbiont’s responses to an unfriendly reception
- 2007
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 130, s. 344-356
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Tidskriftsartikel (refereegranskat)abstract
- The plant responses to infection by pathogenic bacteria have been extensively reviewed in recent years, including the spatial and temporal production of reactive oxygen species (ROS). The immediate and localized release of ROS upon infection, known as the oxidative burst, was shown not only to be part of the hypersensitive response but also likely responsible for mediating, directly or via signal transduction pathways, other plant defence strategies. This paradigm inspired studies in nitrogen-fixing root nodule symbioses, and a parallelism is unavoidable. In rhizobia–legume symbioses, histochemical data revealed the presence of ROS in the host infection threads and in the root nodules primordia. On the other hand, in actinorhizal infections, it has been shown that Alnus glutinosa root exudates induce several oxidative stress response-related proteins in compatible Frankia. These data suggest that the nitrogen-fixing microsymbionts must have had to evolve adaptations to overcome and possibly regulate an unfriendly environment. In this review, particular emphasis will be given to the bacteria antioxidant mechanisms at different developmental stages of the nitrogen-fixing root nodule symbioses.
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| 10. |
- Tavares, Valeria da C., et al.
(författare)
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Out of the Antilles : Fossil phylogenies support reverse colonization of bats to South America
- 2018
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Ingår i: Journal of Biogeography. - : John Wiley & Sons. - 0305-0270 .- 1365-2699. ; 45:4, s. 859-873
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Previous phylogenies of extant short-faced bats (Chiroptera: Stenodermatina) supported either two colonization events from the mainland to the Antilles, or reverse colonization, but lacked both fossil data and statistical modelling of biogeography. Recent multi-locus phylogenies of noctilionoid bats and likelihood modelling of ancestral ranges support a continental origin for the clade. We include all known extinct and extant stenodermatina species and apply statistical modelling to test competing biogeographical hypotheses. Location: The Neotropics, including the Antilles. Methods: We combined mitochondrial and nuclear sequences with 302 new morphological characters to infer phylogenies. Bayesian tip-dating analyses applied codon models to protein-coding genes, with relaxed molecular clocks fitting a compound Poisson process. The combined maximum clade credibility tree was used in comparisons of alternative biogeographical models. Results: The new phylogenies support the fossil Cubanycteris silvai as sister to all extant species of short-faced bats. Among Artibeus (the sister group to short-faced bats), the Antillean fossil A. anthonyi has distinctive characters and is nested within the subgenus Artibeus. The common ancestor of all short-faced bats is inferred to be Antillean, as a mainland origin is unlikely. Founder-event speciation is the most probable process explaining the distribution of these highly divergent fossil lineages. Main conclusions: Dated, character-based phylogenies of fossil species are indispensable for biogeographical inference: without fossils, biogeographical analyses find a mainland origin for short-faced bats. The rate of founder speciation in this clade is twice as high as the estimate from noctilionoids in general, highlighting the role of founder events in the diversification of island taxa. Although rare, reverse colonization contributes key species to continental communities. Short-faced bats, including Cubanycteris, share biomechanical adaptations for a strong bite conferring access to harder figs. We hypothesize these adaptations and characters related to roosting ecology enabled ancestral lineages to successfully establish and diversify on the mainland.
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| 11. |
- Zheng, Tenghao, et al.
(författare)
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Human Leukocyte Antigen Signatures as Pathophysiological Discriminants of Microscopic Colitis Subtypes
- 2024
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Ingår i: Journal of Crohn's and Colitis. - : OXFORD UNIV PRESS. - 1873-9946 .- 1876-4479. ; 18:3, s. 349-359
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: Microscopic colitis [MC] is currently regarded as an inflammatory bowel disease that manifests as two subtypes: collagenous colitis [CC] and lymphocytic colitis [LC]. Whether these represent a clinical continuum or distinct entities is, however, an open question. Genetic investigations may contribute important insight into their respective pathophysiologies. Methods: We conducted a genome-wide association study [GWAS] meta-analysis in 1498 CC, 373 LC patients, and 13 487 controls from Europe and the USA, combined with publicly available MC GWAS data from UK Biobank and FinnGen [2599 MC cases and 552 343 controls in total]. Human leukocyte antigen [HLA] alleles and polymorphic residues were imputed and tested for association, including conditional analyses for the identification of key causative variants and residues. Genetic correlations with other traits and diagnoses were also studied. Results: We detected strong HLA association with CC, and conditional analyses highlighted the DRB1*03:01 allele and its residues Y26, N77, and R74 as key to this association (best p = 1.4 × 10-23, odds ratio [OR] = 1.96). Nominally significant genetic correlations were detected between CC and pneumonia [rg = 0.77; p = 0.048] and oesophageal diseases [rg = 0.45, p = 0.023]. An additional locus was identified in MC GWAS analyses near the CLEC16A and RMI2 genes on chromosome 16 [rs35099084, p = 2.0 × 10-8, OR = 1.31]. No significant association was detected for LC. Conclusion: Our results suggest CC and LC have distinct pathophysiological underpinnings, characterised by an HLA predisposing role only in CC. This challenges existing classifications, eventually calling for a re-evaluation of the utility of MC umbrella definitions.
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| 12. |
- Aad, G., et al.
(författare)
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- 2015
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Tidskriftsartikel (refereegranskat)
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| 13. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 14. |
- Aad, G., et al.
(författare)
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- 2013
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 15
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Tidskriftsartikel (refereegranskat)
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| 15. |
- Aad, G., et al.
(författare)
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- 2013
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Tidskriftsartikel (refereegranskat)
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| 16. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 17. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 18. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 19. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 112:4
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Tidskriftsartikel (refereegranskat)
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| 20. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 112:9
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Tidskriftsartikel (refereegranskat)
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| 21. |
- Aad, G., et al.
(författare)
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- 2013
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 111:23
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Tidskriftsartikel (refereegranskat)
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| 22. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :5
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Tidskriftsartikel (refereegranskat)
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| 23. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :4
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Tidskriftsartikel (refereegranskat)
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| 24. |
- Aad, G., et al.
(författare)
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- 2013
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Tidskriftsartikel (refereegranskat)
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| 25. |
- Aad, G., et al.
(författare)
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- 2013
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :10
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Tidskriftsartikel (refereegranskat)
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| 26. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 27. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 28. |
- Aad, G., et al.
(författare)
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- 2013
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Tidskriftsartikel (refereegranskat)
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| 29. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 112:20
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Tidskriftsartikel (refereegranskat)
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| 30. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :5
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Tidskriftsartikel (refereegranskat)
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| 31. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 32. |
- Aad, G., et al.
(författare)
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- 2013
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Tidskriftsartikel (refereegranskat)
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| 33. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :2
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Tidskriftsartikel (refereegranskat)
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| 34. |
- Aad, G., et al.
(författare)
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- 2013
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :10
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Tidskriftsartikel (refereegranskat)
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| 35. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 36. |
- Aad, G., et al.
(författare)
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- 2013
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Tidskriftsartikel (refereegranskat)
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| 37. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :4
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Tidskriftsartikel (refereegranskat)
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| 38. |
- Glasbey, JC, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 39. |
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| 40. |
- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 41. |
- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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