| 1. |
- Guo, Yiting, et al.
(författare)
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Effect of Side Groups on the Photovoltaic Performance Based on Porphyrin-Perylene Bisimide Electron Acceptors
- 2018
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 10:38, s. 32454-32461
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we developed four porphyrin-based small molecular electron acceptors for non-fullerene organic solar cells, in which different side groups attached to the porphyrin core were selected in order to achieve optimized performance. The molecules contain porphyrin as the core, perylene bisimides as end groups, and the ethynyl unit as the linker. Four side groups, from 2,6-di(dodecyloxy)phenyl to (2-ethylhexyl)thiophen-2-yl, pentadecan-7-yl, and 3,5-di(dodecyloxy)phenyl unit, were applied into the electron acceptors. The new molecules exhibit broad absorption spectra from 300 to 900 nm and high molar extinction coefficients. The molecules as electron acceptors were applied into organic solar cells, showing increased power conversion efficiencies from 1.84 to 5.34%. We employed several techniques, including photoluminescence spectra, electroluminescence spectra, atomic force microscopy, and grazing-incidence wide-angle X-ray to probe the blends to find the effects of the side groups on the photovoltaic properties. We found that the electron acceptors with 2,6-di(dodecyloxy)phenyl units show high-lying frontier energy levels, good crystalline properties, and low nonradiative recombination loss, resulting in possible large phase separation and low energy loss, which is responsible for the low performance. Our results provide a detailed study about the side groups of non-fullerene materials, demonstrating that porphyrin can be used to design electron acceptors toward near-infrared absorption.
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| 2. |
- Levine, David M, et al.
(författare)
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A genome-wide association study identifies new susceptibility loci for esophageal adenocarcinoma and Barrett's esophagus.
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:12
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Tidskriftsartikel (refereegranskat)abstract
- Esophageal adenocarcinoma is a cancer with rising incidence and poor survival. Most such cancers arise in a specialized intestinal metaplastic epithelium, which is diagnostic of Barrett's esophagus. In a genome-wide association study, we compared esophageal adenocarcinoma cases (n = 2,390) and individuals with precancerous Barrett's esophagus (n = 3,175) with 10,120 controls in 2 phases. For the combined case group, we identified three new associations. The first is at 19p13 (rs10419226: P = 3.6 × 10(-10)) in CRTC1 (encoding CREB-regulated transcription coactivator), whose aberrant activation has been associated with oncogenic activity. A second is at 9q22 (rs11789015: P = 1.0 × 10(-9)) in BARX1, which encodes a transcription factor important in esophageal specification. A third is at 3p14 (rs2687201: P = 5.5 × 10(-9)) near the transcription factor FOXP1, which regulates esophageal development. We also refine a previously reported association with Barrett's esophagus near the putative tumor suppressor gene FOXF1 at 16q24 and extend our findings to now include esophageal adenocarcinoma.
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| 3. |
- Liu, Han, et al.
(författare)
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A Chromosome-Level Assembly of Blunt Snout Bream (Megalobrama amblycephala) Genome Reveals an Expansion of Olfactory Receptor Genes in Freshwater Fish
- 2021
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Ingår i: Molecular biology and evolution. - : Oxford University Press. - 0737-4038 .- 1537-1719. ; 38:10, s. 4238-4251
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Tidskriftsartikel (refereegranskat)abstract
- The number of olfactory receptor genes (ORs), which are responsible for detecting diverse odor molecules varies extensively among mammals as a result of frequent gene gains and losses that contribute to olfactory specialization. However, how OR expansions/contractions in fish are influenced by habitat and feeding habit and which OR subfamilies are important in each ecological niche is unknown. Here, we report a major OR expansion in a freshwater herbivorous fish, Megalobrama amblycephala, using a highly contiguous, chromosome-level assembly. We evaluate the possible contribution of OR expansion to habitat and feeding specialization by comparing the OR repertoire in 28 phylogenetically and ecologically diverse teleosts. In total, we analyzed > 4,000 ORs including 3,253 intact, 122 truncated, and 913 pseudogenes. The number of intact ORs is highly variable ranging from 20 to 279. We estimate that the most recent common ancestor of Osteichthyes had 62 intact ORs, which declined in most lineages except the freshwater Otophysa clade that has a substantial expansion in subfamily beta and epsilon ORs. Across teleosts, we found a strong association between duplications of beta and epsilon ORs and freshwater habitat. Nearly, all ORs were expressed in the olfactory epithelium (OE) in three tested fish species. Specifically, all the expanded beta and epsilon ORs were highly expressed in OE of M. amblycephala. Together, we provide molecular and functional evidence for how OR repertoires in fish have undergone gain and loss with respect to ecological factors and highlight the role of beta and epsilon OR in freshwater adaptation.
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| 4. |
- Liu, Tiefeng, et al.
(författare)
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Ground-state electron transfer in all-polymer donor:acceptor blends enables aqueous processing of water-insoluble conjugated polymers
- 2023
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Ingår i: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Water-based conductive inks are vital for the sustainable manufacturing and widespread adoption of organic electronic devices. Traditional methods to produce waterborne conductive polymers involve modifying their backbone with hydrophilic side chains or using surfactants to form and stabilize aqueous nanoparticle dispersions. However, these chemical approaches are not always feasible and can lead to poor material/device performance. Here, we demonstrate that ground-state electron transfer (GSET) between donor and acceptor polymers allows the processing of water-insoluble polymers from water. This approach enables macromolecular charge-transfer salts with 10,000x higher electrical conductivities than pristine polymers, low work function, and excellent thermal/solvent stability. These waterborne conductive films have technological implications for realizing high-performance organic solar cells, with efficiency and stability superior to conventional metal oxide electron transport layers, and organic electrochemical neurons with biorealistic firing frequency. Our findings demonstrate that GSET offers a promising avenue to develop water-based conductive inks for various applications in organic electronics. Chemical approaches to improve aqueous dispersions of conjugated polymers are limited by the feasibility of modifying the backbone or lead to poor performance. Here, Liu et al. show that ground-state electron transfer in donor:acceptor blends aids aqueous dispersion, for high conductivity and solubility.
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| 5. |
- Qian, Deping, et al.
(författare)
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Design rules for minimizing voltage losses in high-efficiency organic solar cells
- 2018
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Ingår i: Nature Materials. - : NATURE PUBLISHING GROUP. - 1476-1122 .- 1476-4660. ; 17:8, s. 703-
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Tidskriftsartikel (refereegranskat)abstract
- The open-circuit voltage of organic solar cells is usually lower than the values achieved in inorganic or perovskite photovoltaic devices with comparable bandgaps. Energy losses during charge separation at the donor-acceptor interface and non-radiative recombination are among the main causes of such voltage losses. Here we combine spectroscopic and quantum-chemistry approaches to identify key rules for minimizing voltage losses: (1) a low energy offset between donor and acceptor molecular states and (2) high photoluminescence yield of the low-gap material in the blend. Following these rules, we present a range of existing and new donor-acceptor systems that combine efficient photocurrent generation with electroluminescence yield up to 0.03%, leading to non-radiative voltage losses as small as 0.21 V. This study provides a rationale to explain and further improve the performance of recently demonstrated high-open-circuit-voltage organic solar cells.
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| 6. |
- Sun, Hui, et al.
(författare)
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Luminosity Function and Event Rate Density of XMM-Newton-selected Supernova Shock Breakout Candidates
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 927:2
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Tidskriftsartikel (refereegranskat)abstract
- A dozen X-ray supernova shock breakout (SN SBO) candidates were reported recently based on XMM-Newton archival data, which increased the X-ray-selected SN SBO sample by an order of magnitude. Assuming that they are genuine SN SBOs, we study the luminosity function (LF) by improving on the method used in our previous work. The light curves and the spectra of the candidates were used to derive the maximum volume within which these objects could be detected with XMM-Newton by simulation. The results show that the SN SBO LF can be described by either a broken power law (BPL) with indices (at the 68% confidence level) of 0.48 +/- 0.28 and 2.11 +/- 1.27 before and after the break luminosity at log(L-b/erg s(-1)) = 45.32 +/- 0.55 or a single power law (SPL) with an index of 0.80 +/- 0.16. The local event rate densities of SN SBOs above 5 x 10(42) erg s (-1) are consistent for two models, i.e., 4.6(-1.3)(+1.7) x 10(4) Gpc(-3) yr(-1) and 4.9(-1.4)(+1.9 )x 10(4) Gpc(-3) yr(-1) for BPL and SPL models, respectively. The number of fast X-ray transients of SN SBO origin can be significantly increased by wide-field X-ray telescopes such as the Einstein Probe.
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| 7. |
- Araghi, Marzieh, et al.
(författare)
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No association between moist oral snuff (snus) use and oral cancer : pooled analysis of nine prospective observational studies
- 2021
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Ingår i: Scandinavian Journal of Public Health. - : Sage Publications. - 1403-4948 .- 1651-1905. ; 49:8, s. 833-840
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Worldwide, smokeless-tobacco use is a major risk factor for oral cancer. Evidence regarding the particular association between Swedish snus use and oral cancer is, however, less clear. We used pooled individual data from the Swedish Collaboration on Health Effects of Snus Use to assess the association between snus use and oral cancer.Methods: A total of 418,369 male participants from nine cohort studies were followed up for oral cancer incidence through linkage to health registers. We used shared frailty models with random effects at the study level, to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for confounding factors.Results: During 9,201,647 person-years of observation, 628 men developed oral cancer. Compared to never-snus use, ever-snus use was not associated with oral cancer (adjusted HR 0.90, 95% CI: 0.74, 1.09). There were no clear trends in risk with duration or intensity of snus use, although lower intensity use (<= 4 cans/week) was associated with a reduced risk (HR 0.65, 95% CI: 0.45, 0.94). Snus use was not associated with oral cancer among never smokers (HR 0.87, 95% CI: 0.57, 1.32).Conclusions: Swedish snus use does not appear to be implicated in the development of oral cancer in men.
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| 8. |
- Araghi, Marzieh, et al.
(författare)
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Smokeless tobacco (snus) use and colorectal cancer incidence and survival : Results from nine pooled cohorts
- 2017
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 45:8, s. 741-748
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Although smoking is considered to be an established risk factor for colorectal cancer, the current evidence on the association between smokeless tobacco and colorectal cancer is scant and inconclusive. We used pooled individual data from the Swedish Collaboration on Health Effects of Snus Use to assess this association.METHODS: A total of 417,872 male participants from nine cohort studies across Sweden were followed up for incidence of colorectal cancer and death. Outcomes were ascertained through linkage to health registers. We used shared frailty models with random effects at the study level to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).RESULTS: During 7,135,504 person-years of observation, 4170 men developed colorectal cancer. There was no clear association between snus use and colorectal cancer overall. Exclusive current snus users, however, had an increased risk of rectal cancer (HR 1.40: 95% CI 1.09, 1.79). There were no statistically significant associations between snus use and either all-cause or colorectal cancer-specific mortality after colorectal cancer diagnosis.CONCLUSIONS: Our findings, from a large sample, do not support any strong relationships between snus use and colorectal cancer risk and survival among men. However, the observed increased risk of rectal cancer is noteworthy, and in merit of further attention.
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| 9. |
- Bao, Qinye, et al.
(författare)
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Trap-Assisted Recombination via Integer Charge Transfer States in Organic Bulk Heterojunction Photovoltaics
- 2014
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Ingår i: Advanced Functional Materials. - : Wiley-VCH Verlag. - 1616-301X .- 1616-3028. ; 24:40, s. 6309-6316
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Tidskriftsartikel (refereegranskat)abstract
- Organic photovoltaics are under intense development and significant focus has been placed on tuning the donor ionization potential and acceptor electron affinity to optimize open circuit voltage. Here, it is shown that for a series of regioregular-poly(3-hexylthiophene): fullerene bulk heterojunction (BHJ) organic photovoltaic devices with pinned electrodes, integer charge transfer states present in the dark and created as a consequence of Fermi level equilibrium at BHJ have a profound effect on open circuit voltage. The integer charge transfer state formation causes vacuum level misalignment that yields a roughly constant effective donor ionization potential to acceptor electron affinity energy difference at the donor-acceptor interface, even though there is a large variation in electron affinity for the fullerene series. The large variation in open circuit voltage for the corresponding device series instead is found to be a consequence of trap-assisted recombination via integer charge transfer states. Based on the results, novel design rules for optimizing open circuit voltage and performance of organic bulk heterojunction solar cells are proposed.
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| 10. |
- Buck, M., et al.
(författare)
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The LIVE program : Results of test L1 and joint analyses on transient molten pool thermal hydraulics
- 2010
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Ingår i: Progress in nuclear energy (New series). - : Elsevier BV. - 0149-1970 .- 1878-4224. ; 52:1, s. 46-60
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Tidskriftsartikel (refereegranskat)abstract
- The development of a corium pool in the lower head and its behaviour is still a critical issue. This concerns, in general, the understanding of a severe accident with core melting, its course, major critical phases and timing, and the influence of these processes on the accident progression as well as, in particular, the evaluation of in-vessel melt retention by external vessel flooding as an accident mitigation strategy. Previous studies were especially related to the in-vessel retention question and often just concentrated on the quasi-steady state behaviour of a large molten pool in the lower head, considered as a bounding configuration. However, non-feasibility of the in-vessel retention concept for high power density reactors and uncertainties e.g. due to layering effects even for low or medium power reactors, turns this to be insufficient. Rather, it is essential to consider the whole evolution of the accident, including e.g. formation and growth of the in-core melt pool, characteristics of corium arrival in the lower head, and molten pool behaviour after the debris re-melting. These phenomena have a strong impact on a potential termination of a severe accident. The general objective of the LIVE program at FZK is to study these phenomena resulting from core melting experimentally in large-scale 3D geometry and in supporting separate-effects tests, with emphasis on the transient behaviour. Up to now, several tests on molten pool behaviour have been performed within the LIVE experimental program with water and with non-eutectic melts (KNO3-NaNO3) as simulant fluids. The results of these experiments, performed in nearly adiabatic and in isothermal conditions, allow a direct comparison with findings obtained earlier in other experimental programs (SIMECO, ACOPO, BALI, etc.) and will be used for the assessment of the correlations derived for the molten pool behaviour. Complementary to other international programs with real corium melts, the results of the LIVE activities also provide data for a better understanding of in-core corium pool behaviour. The experimental results are being used for the development and validation of mechanistic models for the description of molten pool behaviour, In the present paper, a range of different models is used for post-test calculations and comparative analyses. This includes simplified, but fast running models implemented in the severe accident codes ASTEC and ATHLET-CD. Further, a computational tool developed at KTH (PECM model implemented in Fluent) is applied. These calculations are complemented by analyses with the CFD code CONV (thermal hydraulics of heterogeneous, viscous and heat-generating melts) which was developed at IBRAE (Nuclear Safety Institute of Russian Academy) within the RASPLAV project and was further improved within the ISTC 2936 Project.
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