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- Jenniskens, Peter, et al.
(författare)
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The impact and recovery of asteroid 2018 LA
- 2021
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Ingår i: Meteoritics and Planetary Science. - : John Wiley & Sons. - 1086-9379 .- 1945-5100. ; 56:4, s. 844-893
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Tidskriftsartikel (refereegranskat)abstract
- The June 2, 2018 impact of asteroid 2018 LA over Botswana is only the second asteroid detected in space prior to impacting over land. Here, we report on the successful recovery of meteorites. Additional astrometric data refine the approach orbit and define the spin period and shape of the asteroid. Video observations of the fireball constrain the asteroid's position in its orbit and were used to triangulate the location of the fireball's main flare over the Central Kalahari Game Reserve. Twenty‐three meteorites were recovered. A consortium study of eight of these classifies Motopi Pan as an HED polymict breccia derived from howardite, cumulate and basaltic eucrite, and diogenite lithologies. Before impact, 2018 LA was a solid rock of ~156 cm diameter with high bulk density ~2.85 g cm−3, a relatively low albedo pV ~ 0.25, no significant opposition effect on the asteroid brightness, and an impact kinetic energy of ~0.2 kt. The orbit of 2018 LA is consistent with an origin at Vesta (or its Vestoids) and delivery into an Earth‐impacting orbit via the ν6 resonance. The impact that ejected 2018 LA in an orbit toward Earth occurred 22.8 ± 3.8 Ma ago. Zircons record a concordant U‐Pb age of 4563 ± 11 Ma and a consistent 207Pb/206Pb age of 4563 ± 6 Ma. A much younger Pb‐Pb phosphate resetting age of 4234 ± 41 Ma was found. From this impact chronology, we discuss what is the possible source crater of Motopi Pan and the age of Vesta's Veneneia impact basin.
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| 2. |
- Plubell, Deanna L., et al.
(författare)
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Putting Humpty Dumpty Back Together Again : What Does Protein Quantification Mean in Bottom-Up Proteomics? br
- 2022
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 21:4, s. 891-898
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Tidskriftsartikel (refereegranskat)abstract
- Bottom-up proteomics provides peptide measurements and has beeninvaluable for moving proteomics into large-scale analyses. Commonly, a singlequantitative value is reported for each protein-coding gene by aggregating peptidequantities into protein groups following protein inference or parsimony. However, giventhe complexity of both RNA splicing and post-translational protein modification, it isoverly simplistic to assume that all peptides that map to a singular protein-coding genewill demonstrate the same quantitative response. By assuming that all peptides from aprotein-coding sequence are representative of the same protein, we may miss thediscovery of important biological differences. To capture the contributions of existingproteoforms, we need to reconsider the practice of aggregating protein values to a singlequantity per protein-coding gene.
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| 3. |
- Campbell, Christine, et al.
(författare)
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Markers of steroid receptor, kinase signalling pathways and Ki-67 expression in relation to tamoxifen sensitivity and resistance
- 2020
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Ingår i: Translational Breast Cancer Research. - : AME Publishing Company. - 2218-6778. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- Background: It remains clinically important to identify ER positive breast cancers likely to respond to tamoxifen (TAM) and so we aimed to select a group of biomarkers able to predict response. We also assessed whether data from different sample types [tumor microarrays (TMAs) and core biopsies] or tumor sites could be combined for biomarker studies.Methods: A total of 123 endocrine treatment naïve patients with known ER and HER2 status treated with TAM had paraffin-embedded tumor tissue available either as TMAs (n=102) or core biopsies (n=21). TMA cores were collected from three different tumor sites, two central and one peripheral. Ten biomarkers were evaluated by immunohistochemistry, for % positivity and/or H-Score, comprising: ER, HER2, Ki-67, phosphorylated forms of ER (Ser118), IGF1R, PRAS40, Akt & MAPK (ERK1/2), and PTEN & androgen receptor expression (AR). Each tumor was analysed for Akt1 E17K somatic mutation using BEAMing technology. Patient outcome was assessed by clinical benefit (CB) rate & survival analyses [time to progression (TTP) and time to death (TTD)].Results: There was no significant difference in % positivity or H-Score between central & peripheral tumor sites for all biomarkers examined. After False Discovery Rate (FDR) correction differences (P<0.05) were observed between the two central samples only for HER2 & pER118 and pPRAS40. However, differences in biomarker expression were common between core biopsies and TMAs. Only 2/123 (1.6%) tumors had Akt1 E17K mutations. Univariate and multivariate analyses identified that lower levels of PTEN and higher levels of Ki-67 (% positivity) were predictive of poor outcome (TTP & TTD) following TAM. Higher ER. lower Ki-67 and AR/ER ratio <2 predicted increased CB rate.Conclusions: There were few differences in marker expression between TMAs from different intra-tumoral sites. More marked differences between TMAs and core biopsies suggest caution if combining such datasets. Loss of PTEN, a key regulator of the PI3K/Akt pathway, was the only RTK/kinase signaling biomarker related to poorer clinical outcome. PTEN along with ER & lower Ki-67 proved the most predictive markers for better outcome (TTP & TTD and/or CBR) following TAM treatment.Keywords: ER+ breast cancer; Akt pathway; tamoxifen
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| 4. |
- Ito, Akihiko, et al.
(författare)
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Soil carbon sequestration simulated in CMIP6-LUMIP models : Implications for climatic mitigation
- 2020
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9318 .- 1748-9326. ; 15:12
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Tidskriftsartikel (refereegranskat)abstract
- Land-use change affects both the quality and quantity of soil organic carbon (SOC) and leads to changes in ecosystem functions such as productivity and environmental regulation. Future changes in SOC are, however, highly uncertain owing to its heterogeneity and complexity. In this study, we analyzed the outputs of simulations of SOC stock by Earth system models (ESMs), most of which are participants in the Land-Use Model Intercomparison Project. Using a common protocol and the same forcing data, the ESMs simulated SOC distribution patterns and their changes during historical (1850-2014) and future (2015-2100) periods. Total SOC stock increased in many simulations over the historical period (30 ± 67 Pg C) and under future climate and land-use conditions (48 ± 32 Pg C for ssp126 and 49 ± 58 Pg C for ssp370). Land-use experiments indicated that changes in SOC attributable to land-use scenarios were modest at the global scale, in comparison with climatic and rising CO2 impacts, but they were notable in several regions. Future net soil carbon sequestration rates estimated by the ESMs were roughly 0.4‰ yr-1 (0.6 Pg C yr-1). Although there were considerable inter-model differences, the rates are still remarkable in terms of their potential for mitigation of global warming. The disparate results among ESMs imply that key parameters that control processes such as SOC residence time need to be better constrained and that more comprehensive representation of land management impacts on soils remain critical for understanding the long-term potential of soils to sequester carbon.
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