| 1. |
- Besnard, Céline, et al.
(författare)
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Diquino[4,3-b;3 ',4 '-e][1,4]thiaselenine
- 2006
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Ingår i: Acta Crystallographica Section E: Structure Reports Online. - 1600-5368. ; 62:8, s. 3203-3205
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Tidskriftsartikel (refereegranskat)abstract
- The title compound, C18H10N2SSe, is a pentacyclic ring system folded along the S center dot center dot center dot Se vector. The central thiaselenine ring adopts a boat conformation and the two halves of the molecule are related by a crystallographic mirror plane.
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| 2. |
- Ni, Wenjun, et al.
(författare)
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Ultrafast Tuning of Various Photochemical Pathways in Perylene-TCNQ Charge-Transfer Crystals
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:25, s. 13894-13901
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Tidskriftsartikel (refereegranskat)abstract
- Excited-state dynamics in a strong charge-transfer (perylene)(3)-7,7,8,8-tetracyanoquinodimethane (P3T1) single-crystal system was studied by use of femtosecond transient absorption and upconversion time-resolved fluorescence techniques. Charge separation within 0.6-1.2 ps and subsequent recombination within 6.6-12 ps was demonstrated. Moreover, the excited-state dynamics in the P3T1 crystal was found to depend on excitation energies. Excitation of upper excited electronic states (4.96 eV) leads to efficient direct population of perylene triplet states via singlet fission. At lower excitation photon energies, enhancement of triplet state formation via intersystem crossing as a result of efficient spin-orbit charge transfer was observed. By varying the excitation wavelength, the performance of optoelectronic devices can be tuned, i.e., photon absorption, free carrier transfer, mobility, and recombination.
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| 3. |
- Nord, Helena, et al.
(författare)
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Characterization of novel and complex genomic aberrations in glioblastoma using a 32K BAC array
- 2009
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Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1522-8517 .- 1523-5866. ; 11:6, s. 803-818
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Tidskriftsartikel (refereegranskat)abstract
- Glioblastomas (GBs) are malignant CNS tumors often associated with devastating symptoms. Patients with GB have a very poor prognosis, and despite treatment, most of them die within 12 months from diagnosis. Several pathways, such as the RAS, tumor protein 53 (TP53), and phosphoinositide kinase 3 (PIK3) pathways, as well as the cell cycle control pathway, have been identified to be disrupted in this tumor. However, emerging data suggest that these aberrations represent only a fraction of the genetic changes involved in gliomagenesis. In this study, we have applied a 32K clone-based genomic array, covering 99% of the current assembly of the human genome, to the detailed genetic profiling of a set of 78 GBs. Complex patterns of aberrations, including high and narrow copy number amplicons, as well as a number of homozygously deleted loci, were identified. Amplicons that varied both in number (three on average) and in size (1.4 Mb on average) were frequently detected (81% of the samples). The loci encompassed not only previously reported oncogenes (EGFR, PDGFRA, MDM2, and CDK4) but also numerous novel oncogenes as GRB10, MKLN1, PPARGC1A, HGF, NAV3, CNTN1, SYT1, and ADAMTSL3. BNC2, PTPLAD2, and PTPRE, on the other hand, represent novel candidate tumor suppressor genes encompassed within homozygously deleted loci. Many of these genes are already linked to several forms of cancer; others represent new candidate genes that may serve as prognostic markers or even as therapeutic targets in the future. The large individual variation observed between the samples demonstrates the underlying complexity of the disease and strengthens the demand for an individualized therapy based on the genetic profile of the patient.
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| 4. |
- Zhao, Tongyu, et al.
(författare)
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Revealing ultrafast relaxation dynamics in six-thiophene thin film and single crystal
- 2021
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Ingår i: Journal of Photochemistry and Photobiology A. - : Elsevier B.V.. - 1010-6030 .- 1873-2666. ; 404
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Tidskriftsartikel (refereegranskat)abstract
- The excited state dynamics of six-thiophene (6T) thin film and single crystal was studied by time-resolved fluorescence and femtosecond transient absorption techniques under different excitation conditions. The dominant process in 6T system is the generation of ion pairs, dissociated to polarons staying for up to 130−3700 ns in film and 1 ms in crystal. Singlet fission (SF) was directly observed from the upper vibrational levels of the first excited singlet state S1 in 6T thin film/single crystal within 30 fs, which competes with intramolecular vibrational relaxation. Triplet state lifetime is dramatically shortened from 6T single crystal (1 ms) to thin film (4 ns) due to triplet-triplet annihilation, which is influenced by structural defects in amorphous regions of 6T film. Compared with 6T crystal, the partially ordered semicrystalline morphology of 6T film suggests the impact of well-structured crystallinity and molecular packing on the photocarriers transport dynamics and lifetime of triplet state. Moreover, excitation to upper excited singlet state (4.96 eV) leads to a higher yield of polarons (factor of 4), while SF in film/crystal is fully suppressed. Existence of long-lived photogenerated polarons may count π-conjugated oligomers as promising materials for developing organic-molecule-based optoelectroinc devices.
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| 5. |
- Zhao, Tongyu, et al.
(författare)
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Singlet Fission, Polaron Formation, and Energy Transfer in Indolo[3,2-b]carbazole Thin Films and Single Crystals
- 2021
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 125:34, s. 18827-18833
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Tidskriftsartikel (refereegranskat)abstract
- The ultrafast excited-state relaxation dynamics of indolo[3,2-b]carbazole (ICZ) molecules were investigated in thin films and single crystals. In the ICZ film, singlet fission (SF) was directly observed both from the upper excited singlet states S-N within 480-850 fs and from the upper vibrational levels of the singlet state S-1 within 6-11 ps, which fully suppressed the intramolecular charge transfer (CT) process in S-1. In the ICZ crystal, the exciton relaxation through SF and polaron formation compete in the ultrafast timescale (<30 fs), which is accompanied by a thermally induced broadening of the S-1-S-N absorption band in the transient absorption spectra. The triplet-state lifetime is shortened from ICZ crystals (>1 ms) to films (2 mu s) due to SF with subsequent triplet-triplet annihilation, suggesting the impact of well-structured crystallinity and molecular packing on the exciton transport dynamics. The efficient SF together with well-characterized energy transfer and CT properties of ICZ solids extends the usage of ICZ-core-based organic materials in photovoltaic and electrochemical applications.
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