SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L773:0028 0836 "

Sökning: L773:0028 0836

  • Resultat 891-900 av 1305
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
891.
  •  
892.
  • Pedersen, Helle Krogh, et al. (författare)
  • Human gut microbes impact host serum metabolome and insulin sensitivity
  • 2016
  • Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 535:7612, s. 376-381
  • Tidskriftsartikel (refereegranskat)abstract
    • Insulin resistance is a forerunner state of ischaemic cardiovascular disease and type 2 diabetes. Here we show how the human gut microbiome impacts the serum metabolome and associates with insulin resistance in 277 non-diabetic Danish individuals. The serum metabolome of insulin-resistant individuals is characterized by increased levels of branched-chain amino acids (BCAAs), which correlate with a gut microbiome that has an enriched biosynthetic potential for BCAAs and is deprived of genes encoding bacterial inward transporters for these amino acids. Prevotella copri and Bacteroides vulgatus are identified as the main species driving the association between biosynthesis of BCAAs and insulin resistance, and in mice we demonstrate that P. copri can induce insulin resistance, aggravate glucose intolerance and augment circulating levels of BCAAs. Our findings suggest that microbial targets may have the potential to diminish insulin resistance and reduce the incidence of common metabolic and cardiovascular disorders.
  •  
893.
  • Pedersen, Kai O. (författare)
  • Sedimentation equilibrium measurements with low molecular substances in the ultra-centrifuge
  • 1935
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 135, s. 304-305
  • Tidskriftsartikel (refereegranskat)abstract
    • The calculated molecular weights agreed fairly well with the known values for these substances except in the cases of the substance with the lowest molecular weight, CsCl, where the difference in concentration was very small. Quite recently, Prof. Svedberg has greatly improved his ultra-centrifuge (see Svedberg, loc.
  •  
894.
  • Pedersen, Kai O. (författare)
  • Temperature stability and denaturation of serum albumin
  • 1931
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 128, s. 150-151
  • Tidskriftsartikel (refereegranskat)abstract
    • It has been shown by Svedberg and Sjögren1 that at ordinary temperature serum albumin is stable (that is, homogeneous with regard to molecular weight) in a region of pH varying between 4 and 9. These authors have also shown that outside of the stability region, but not too far from it, the serum albumin molecule is dissociated into smaller molecules. This first stage of breaking up of the molecule probably means the formation of particles of half the weight of the original molecule. The complete breaking up of the molecule follows immediately after this stage. The first stage has been shown to be reversible with regard to the molecular weight.
  •  
895.
  • Pellegrini, Adam F.A., et al. (författare)
  • Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity
  • 2018
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 553:7687, s. 194-198
  • Tidskriftsartikel (refereegranskat)abstract
    • Fire frequency is changing globally and is projected to affect the global carbon cycle and climate. However, uncertainty about how ecosystems respond to decadal changes in fire frequency makes it difficult to predict the effects of altered fire regimes on the carbon cycle; for instance, we do not fully understand the long-term effects of fire on soil carbon and nutrient storage, or whether fire-driven nutrient losses limit plant productivity. Here we analyse data from 48 sites in savanna grasslands, broadleaf forests and needleleaf forests spanning up to 65 years, during which time the frequency of fires was altered at each site. We find that frequently burned plots experienced a decline in surface soil carbon and nitrogen that was non-saturating through time, having 36 per cent (±13 per cent) less carbon and 38 per cent (±16 per cent) less nitrogen after 64 years than plots that were protected from fire. Fire-driven carbon and nitrogen losses were substantial in savanna grasslands and broadleaf forests, but not in temperate and boreal needleleaf forests. We also observe comparable soil carbon and nitrogen losses in an independent field dataset and in dynamic model simulations of global vegetation. The model study predicts that the long-term losses of soil nitrogen that result from more frequent burning may in turn decrease the carbon that is sequestered by net primary productivity by about 20 per cent of the total carbon that is emitted from burning biomass over the same period. Furthermore, we estimate that the effects of changes in fire frequency on ecosystem carbon storage may be 30 per cent too low if they do not include multidecadal changes in soil carbon, especially in drier savanna grasslands. Future changes in fire frequency may shift ecosystem carbon storage by changing soil carbon pools and nitrogen limitations on plant growth, altering the carbon sink capacity of frequently burning savanna grasslands and broadleaf forests.
  •  
896.
  • Pelletier, Stefan, et al. (författare)
  • Vanadium oxide and a sharp onset of cold-trapping on a giant exoplanet
  • 2023
  • Ingår i: Nature. - 0028-0836. ; 619:7970, s. 491-494
  • Tidskriftsartikel (refereegranskat)abstract
    • The abundance of refractory elements in giant planets can provide key insights into their formation histories1. Owing to the low temperatures of the Solar System giants, refractory elements condense below the cloud deck, limiting sensing capabilities to only highly volatile elements2. Recently, ultra-hot giant exoplanets have allowed for some refractory elements to be measured, showing abundances broadly consistent with the solar nebula with titanium probably condensed out of the photosphere3,4. Here we report precise abundance constraints of 14 major refractory elements on the ultra-hot giant planet WASP-76b that show distinct deviations from proto-solar and a sharp onset in condensation temperature. In particular, we find nickel to be enriched, a possible sign of the accretion of the core of a differentiated object during the evolution of the planet. Elements with condensation temperatures below 1,550 K otherwise closely match those of the Sun5 before sharply transitioning to being strongly depleted above 1,550 K, which is well explained by nightside cold-trapping. We further unambiguously detect vanadium oxide on WASP-76b, a molecule long suggested to drive atmospheric thermal inversions6, and also observe a global east–west asymmetry7 in its absorption signals. Overall, our findings indicate that giant planets have a mostly stellar-like refractory elemental content and suggest that temperature sequences of hot Jupiter spectra can show abrupt transitions wherein a mineral species is either present or completely absent if a cold trap exists below its condensation temperature8.
  •  
897.
  • Pennekamp, Frank, et al. (författare)
  • Biodiversity increases and decreases ecosystem stability
  • 2018
  • Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 563:7729, s. 109-
  • Tidskriftsartikel (refereegranskat)abstract
    • Losses and gains in species diversity affect ecological stability(1-7) and the sustainability of ecosystem functions and services(8-13). Experiments and models have revealed positive, negative and no effects of diversity on individual components of stability, such as temporal variability, resistance and resilience(2,3,6,11,12,14). How these stability components covary remains poorly understood(15). Similarly, the effects of diversity on overall ecosystem stability(16), which is conceptually akin to ecosystem multifunctionality(17,18), remain unknown. Here we studied communities of aquatic ciliates to understand how temporal variability, resistance and overall ecosystem stability responded to diversity (that is, species richness) in a large experiment involving 690 micro-ecosystems sampled 19 times over 40 days, resulting in 12,939 samplings. Species richness increased temporal stability but decreased resistance to warming. Thus, two stability components covaried negatively along the diversity gradient. Previous biodiversity manipulation studies rarely reported such negative covariation despite general predictions of the negative effects of diversity on individual stability components(3). Integrating our findings with the ecosystem multifunctionality concept revealed hump- and U-shaped effects of diversity on overall ecosystem stability. That is, biodiversity can increase overall ecosystem stability when biodiversity is low, and decrease it when biodiversity is high, or the opposite with a U-shaped relationship. The effects of diversity on ecosystem multifunctionality would also be hump- or U-shaped if diversity had positive effects on some functions and negative effects on others. Linking the ecosystem multifunctionality concept and ecosystem stability can transform the perceived effects of diversity on ecological stability and may help to translate this science into policy-relevant information.
  •  
898.
  •  
899.
  • Percec, V., et al. (författare)
  • Self-assembly of amphiphilic dendritic dipeptides into helical pores
  • 2004
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 430:7001, s. 764-768
  • Tidskriftsartikel (refereegranskat)abstract
    • Natural pore-forming proteins act as viral helical coats(1) and transmembrane channels(2-4), exhibit antibacterial activity(5) and are used in synthetic systems, such as for reversible encapsulation(6) or stochastic sensing(7). These diverse functions are intimately linked to protein structure(1-4). The close link between protein structure and protein function makes the design of synthetic mimics a formidable challenge, given that structure formation needs to be carefully controlled on all hierarchy levels, in solution and in the bulk. In fact, with few exceptions(8,9), synthetic pore structures capable of assembling into periodically ordered assemblies that are stable in solution and in the solid state(10-13) have not yet been realized. In the case of dendrimers, covalent(14) and non- covalent(15) coating and assembly of a range of different structures(15-17) has only yielded closed columns(18). Here we describe a library of amphiphilic dendritic dipeptides that self-assemble in solution and in bulk through a complex recognition process into helical pores. We find that the molecular recognition and self-assembly process is sufficiently robust to tolerate a range of modifications to the amphiphile structure, while preliminary proton transport measurements establish that the pores are functional. We expect that this class of self-assembling dendrimers will allow the design of a variety of biologically inspired systems with functional properties arising from their porous structure.
  •  
900.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 891-900 av 1305
Typ av publikation
tidskriftsartikel (1272)
forskningsöversikt (13)
annan publikation (10)
recension (9)
konferensbidrag (1)
Typ av innehåll
refereegranskat (1110)
övrigt vetenskapligt/konstnärligt (186)
populärvet., debatt m.m. (9)
Författare/redaktör
Lindblad-Toh, Kersti ... (20)
Ahlberg, Per E. (19)
Kim, J. (12)
Melander, Olle (12)
Bäckhed, Fredrik, 19 ... (11)
Groop, Leif (11)
visa fler...
Deloukas, Panos (11)
Palotie, A (11)
Thorsteinsdottir, Un ... (11)
Lind, Lars (10)
Gudnason, V (10)
Volzke, H (10)
Wareham, Nicholas J. (10)
McCarthy, Mark I (10)
Vollenweider, P. (10)
Bertsche, W. (10)
Fajans, J. (10)
Hangst, J. S. (10)
Wurtele, J. S. (10)
Borg, Åke (10)
Evans, A. (9)
Castelo-Branco, G (9)
Wang, Q. (9)
Hultman, CM (9)
Rudan, Igor (9)
van der Werf, D. P. (9)
Kellis, Manolis (9)
van Duijn, Cornelia ... (9)
Boehnke, Michael (9)
Cesar, C. L. (9)
Charlton, M. (9)
Eriksson, S. (9)
Friesen, T. (9)
Fujiwara, M. C. (9)
Gill, D. R. (9)
Hardy, W. N. (9)
Hayden, M. E. (9)
Jonsell, Svante (9)
Kurchaninov, L. (9)
Madsen, N. (9)
Menary, S. (9)
Olchanski, K. (9)
Olin, A. (9)
Pusa, P. (9)
Robicheaux, F. (9)
Sarid, E. (9)
Silveira, D. M. (9)
So, C. (9)
Thompson, R. I. (9)
Thorleifsson, Gudmar (9)
visa färre...
Lärosäte
Uppsala universitet (323)
Karolinska Institutet (308)
Lunds universitet (184)
Stockholms universitet (178)
Göteborgs universitet (112)
Umeå universitet (91)
visa fler...
Chalmers tekniska högskola (72)
Kungliga Tekniska Högskolan (70)
Sveriges Lantbruksuniversitet (53)
Linköpings universitet (46)
Linnéuniversitetet (17)
Luleå tekniska universitet (12)
RISE (10)
Naturhistoriska riksmuseet (10)
Örebro universitet (7)
Högskolan i Halmstad (4)
Mittuniversitetet (4)
Handelshögskolan i Stockholm (3)
Mälardalens universitet (2)
Jönköping University (2)
Södertörns högskola (2)
Högskolan i Gävle (1)
IVL Svenska Miljöinstitutet (1)
visa färre...
Språk
Engelska (1301)
Odefinierat språk (3)
Svenska (1)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (644)
Medicin och hälsovetenskap (222)
Samhällsvetenskap (46)
Lantbruksvetenskap (45)
Teknik (30)
Humaniora (26)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy