| 1. |
- Campbell, PJ, et al.
(författare)
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Pan-cancer analysis of whole genomes
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
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Tidskriftsartikel (refereegranskat)abstract
- Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
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| 2. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 3. |
- Chen, W, et al.
(författare)
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Fabrication and luminescence of ZnS : Mn2+ nanoflowers
- 2005
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Ingår i: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 0000-0000. ; 5:9, s. 1309-1322
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Tidskriftsartikel (refereegranskat)abstract
- Visually striking nanoflowers composed of ZnS:Mn2+ nanoparticles are prepared and characterized. The configurations of these fractal structures are very sensitive to both the pH values of the particle solutions from which they are precipitated and the substrates on which they are deposited. At pH 2.2, the fractal structures resemble trees without leaves; at pH 7.7, they are tree-like with four arms and at pH 11.0 they resemble trees with six arms. High resolution transmission microscopy reveals that the nanoflowers are composed of ZnS:Mn2+ nanoparticles of 2-5 nm in size. X-ray photoelectron spectral data indicate that the sample compositions of nitrogen, chlorine, and sulfur vary gradually with pH values of the solutions. These changes may have an impact on both the fractal configuration and the luminescence properties. The emission spectra of the particle solutions at pH values of 2.2 and 11.0 are similar with the emission maximum at 475 nm. As the pH value approaches 7.7, the emission spectral maximum shifts to longer wavelengths. At a pH value of 7.7, the emission peak wavelength is the reddest, 520 nm. The emission peak of the nanoflowers at a pH value of 9.3 is 510 nm, while the emission spectrum of the nanoflowers at 5.2 has two peaks at 500 nm and 440 nm, respectively. These blue-green emissions are attributed to defects and are the dominant luminescence from the nanoflowers. The emission from Mn2+ dopant is only observed in the delayed spectra of the fractal solid samples.
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| 4. |
- Chen, W, et al.
(författare)
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Structure, luminescence, and dynamics of Eu2O3 nanoparticles in MCM-41
- 2002
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 106:28, s. 7034-7041
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Tidskriftsartikel (refereegranskat)abstract
- The structure, luminescence spectroscopy, and lifetime decay dynamics of Eu2O3 nanoparticles formed in MCM-41 have been investigated. Both X-ray diffraction and high-resolution transmission electron microscopic observations indicate that Eu2O3 nanoparticles of monoclinic structure are formed inside channels of MCM-41 by heating at 140 degreesC. However, heat treatment at 600 or 700 degreesC causes migration of Eu2O3 from the MCM-41 channels, forming nanoparticles of cubic structure outside the MCM-41 channels. After heating to 900 degreesC, some of the cubic Eu2O3 particles change to monoclinic Eu2O3, and the MCM-41 structure breaks down and a different or disordered phase is formed. The feature of the hypersensitive D-5(0) --> F-7(2) emission profile of Eu3+ is used to follow the structural changes. In the luminescence spectrum of the sample prepared at 140 degreesC, the emission spectrum is dominated by peaks at 615 and 623 nm, while in the other samples a peak at 612 nm is prevalent. Photoluminescence lifetimes show the existence of short (<1 mus) and long (microsecond to millisecond) components for each sample. The fast decay is attributed to quenching by surface states of the nanoparticles or energy transfer to the MCM-41, while the longer time decays show the effects of concentration quenching. The monoclinic sample prepared at 140 degreesC shows a higher luminescence intensity than the cubic samples or the bulk powder. These observations indicate that MCM-41 as a template can be used for making and stabilizing monoclinic rare earth oxides, which normally are stable only at high temperatures and high pressures. More importantly, the nanophase Eu2O3/MCM-41 composite materials formed at low temperatures might represent a new type of efficient luminescence material with fast response, with potential applications in lighting and displays.
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| 5. |
- Chen, W, et al.
(författare)
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Temperature and pressure dependences of the Mn2+ and donor-acceptor emissions in ZnS : Mn2+ nanoparticles
- 2002
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Ingår i: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 92:4, s. 1950-1955
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Tidskriftsartikel (refereegranskat)abstract
- Temperature and pressure dependent measurements have been performed on 3.5 nm ZnS:Mn2+ nanoparticles. As temperature increases, the donor-acceptor (DA) emission of ZnS:Mn2+ nanoparticles at 440 nm shifts to longer wavelengths while the Mn2+ emission (T-4(1)-(6)A(1)) shifts to shorter wavelengths. Both the DA and Mn2+ emission intensities decrease with temperature with the intensity decrease of the DA emission being much more pronounced. The intensity decreases are fit well with the theory of thermal quenching. As pressure increases, the Mn2+ emission shifts to longer wavelengths while the DA emission wavelength remains almost constant. The pressure coefficient of the DA emission in ZnS:Mn2+ nanoparticles is approximately -3.2 meV/GPa, which is significantly smaller than that measured for bulk materials. The relatively weak pressure dependence of the DA emission is attributed to the increase of the binding energies and the localization of the defect wave functions in nanoparticles. The pressure coefficient of Mn2+ emission in ZnS:Mn2+ nanoparticles is roughly -34.3 meV/GPa, consistent with crystal field theory. The results indicate that the energy transfer from the ZnS host to Mn2+ ions is mainly from the recombination of carriers localized at Mn2+ ions. (C) 2002 American Institute of Physics.
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| 6. |
- Chen, W, et al.
(författare)
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The origin of x-ray luminescence from CdTe nanoparticles in CdTe/BaFBr : Eu2+ nanocomposite phosphors
- 2006
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Ingår i: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 99:3
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Tidskriftsartikel (refereegranskat)abstract
- X-ray luminescence from CdTe nanoparticles is observed when CdTe nanoparticles are encapsulated into BaFBr:Eu2+ phosphors. In contrast, negligible x-ray luminescence is observed from the unencapsulated nanoparticles, either in solution or in solid form. The origin of the x-ray luminescence is attributed to the effective energy transfer from Eu2+ ions to CdTe nanoparticles in the nanocomposite materials. The x-ray luminescence of these nanocomposites is dose dependent and the emission wavelength is size adjustable which may allow use as a type of dosimeter for both in vitro and in vivo applications. (c) 2006 American Institute of Physics.
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| 7. |
- Chen, W, et al.
(författare)
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Utilizing nanofabrication to construct strong, luminescent materials
- 2006
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 17:10, s. 2595-2601
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent materials have been utilized widely in applications from lighting to sensing. The new development of technologies based on luminescence requires the materials to have high luminescence efficiency and mechanical strength. In this paper, we report the fabrication of luminescent materials possessing high mechanical strength by nanofabrication with polyvinyl alcohol used as a stabilizer or coupling agent. X-ray diffraction and high-resolution transmission microscope observations reveal that the nanocomposite sample contains ZnS and ZnO nanoparticles as well as kozoite and sodium nitrate. The mechanical strength and hardness of these nanocomposites are reasonably high, higher than polycarbonate and some carbon nanotube reinforced nanocomposites. Strong luminescence is observed in the new nanocomposites and the luminescence intensity does not degrade following up to 30 min of x-ray irradiation. Our results indicate that nanofabrication may provide a good method to improve the mechanical strength of luminescent materials for some applications in which high-strength luminescent materials are needed.
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