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| 14. |
- Allum, F., et al.
(författare)
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A localized view on molecular dissociation via electron-ion partial covariance
- 2022
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Ingår i: Communications Chemistry. - : Springer Science and Business Media LLC. - 2399-3669. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- Inner-shell photoelectron spectroscopy provides an element-specific probe of molecular structure, as core-electron binding energies are sensitive to the chemical environment. Short-wavelength femtosecond light sources, such as Free-Electron Lasers (FELs), even enable time-resolved site-specific investigations of molecular photochemistry. Here, we study the ultraviolet photodissociation of the prototypical chiral molecule 1-iodo-2-methylbutane, probed by extreme-ultraviolet (XUV) pulses from the Free-electron LASer in Hamburg (FLASH) through the ultrafast evolution of the iodine 4d binding energy. Methodologically, we employ electron-ion partial covariance imaging as a technique to isolate otherwise elusive features in a two-dimensional photoelectron spectrum arising from different photofragmentation pathways. The experimental and theoretical results for the time-resolved electron spectra of the 4d(3/2) and 4d(5/2) atomic and molecular levels that are disentangled by this method provide a key step towards studying structural and chemical changes from a specific spectator site. Coincidence experiments at free-electron lasers enable time resolved site-specific investigations of molecular photochemistry at high signal rates, but isolating individual dissociation processes still poses a considerable technical challenge. Here, the authors use electron-ion partial covariance imaging to isolate otherwise elusive chemical shifts in UV-induced photofragmentation pathways of the prototypical chiral molecule 1-iodo-2-methylbutane.
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| 16. |
- Eap, C. B., et al.
(författare)
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Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests) : focus on antidepressants
- 2021
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Ingår i: World Journal of Biological Psychiatry. - : Taylor & Francis Group. - 1562-2975 .- 1814-1412. ; 22:8, s. 561-628
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Forskningsöversikt (refereegranskat)abstract
- Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient. Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug. Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.
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| 17. |
- Batel, A., et al.
(författare)
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Histological, enzymatic and chemical analyses of the potential effects of differently sized microplastic particles upon long-term ingestion in zebrafish (Danio rerio)
- 2020
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Ingår i: Marine Pollution Bulletin. - : Elsevier. - 0025-326X .- 1879-3363. ; 153
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Tidskriftsartikel (refereegranskat)abstract
- In microplastics (MPs) research, there is an urgent need to critically reconsider methodological approaches and results published, since public opinion and political decisions might be based on studies using debatable methods and reporting questionable results. For instance, recent studies claim that MPs induce intestinal damage and that relatively large MPs are transferred to, e.g., livers in fish. However, there is methodological criticism and considerable concern whether MP transfer to surrounding tissues is plausible. Likewise, there is an ongoing discussion in MP research if MPs act as vectors for adsorbed hazardous chemicals. In this study, effects of very small (4–6 μm) and very large (125–500 μm) benzo(a) pyrene (BaP)-spiked polyethylene (PE) particles administered via different uptake routes (food chain vs. direct uptake) were compared in a 21-day zebrafish (Danio rerio) feeding experiment. Particular care was taken to prevent cross-contamination of MPs during dissection and histological sample preparation. In contrast to numerous reports in literature describing similar approaches, independent of exposure route and MP size, no adverse effects could be detected. Likewise, no BaP accumulation could be documented, and MPs were exclusively seen in the lumen of the intestinal tract, which, however, did not induce any histopathological effects. Results indicate that in fish MPs are taken up, pass along the intestinal lumen and are excreted without any symptoms of adverse effects.
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| 20. |
- Duran-Ferrer, Marti, et al.
(författare)
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The proliferative history shapes the DNA methylome of B-cell tumors and predicts clinical outcome
- 2020
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Ingår i: NATURE CANCER. - : Springer Nature. - 2662-1347. ; 1:11, s. 1066-1081
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Tidskriftsartikel (refereegranskat)abstract
- We report a systematic analysis of the DNA methylation variability in 1,595 samples of normal cell subpopulations and 14 tumor subtypes spanning the entire human B-cell lineage. Differential methylation among tumor entities relates to differences in cellular origin and to de novo epigenetic alterations, which allowed us to build an accurate machine learning-based diagnostic algorithm. We identify extensive individual-specific methylation variability in silenced chromatin associated with the proliferative history of normal and neoplastic B cells. Mitotic activity generally leaves both hyper- and hypomethylation imprints, but some B-cell neoplasms preferentially gain or lose DNA methylation. We construct a DNA-methylation-based mitotic clock, called epiCMIT, whose lapse magnitude represents a strong independent prognostic variable in B-cell tumors and is associated with particular driver genetic alterations. Our findings reveal DNA methylation as a holistic tracer of B-cell tumor developmental history, with implications in differential diagnosis and the prediction of clinical outcome. Martin-Subero and colleagues analyze DNA methylation patterns in B-cell tumors and their normal cells of origin, and develop epiCMIT, a methylation-based mitotic clock with prognostic relevance.
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