| 1. |
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| 2. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 4. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 5. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 6. |
- Zhang, Huai, et al.
(författare)
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A global survey on the use of the international classification of diseases codes for metabolic dysfunction-associated fatty liver disease.
- 2024
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Ingår i: Hepatology international. - 1936-0541.
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Tidskriftsartikel (refereegranskat)abstract
- With the implementation of the 11th edition of the International Classification of Diseases (ICD-11) and the publication of the metabolic dysfunction-associated fatty liver disease (MAFLD) nomenclature in 2020, it is important to establish consensus for the coding of MAFLD in ICD-11. This will inform subsequent revisions of ICD-11.Using the Qualtrics XM and WJX platforms, questionnaires were sent online to MAFLD-ICD-11 coding collaborators, authors of papers, and relevant association members.A total of 890 international experts in various fields from 61 countries responded to the survey. We also achieved full coverage of provincial-level administrative regions in China. 77.1% of respondents agreed that MAFLD should be represented in ICD-11 by updating NAFLD, with no significant regional differences (77.3% in Asia and 76.6% in non-Asia, p=0.819). Over 80% of respondents agreed or somewhat agreed with the need to assign specific codes for progressive stages of MAFLD (i.e. steatohepatitis) (92.2%), MAFLD combined with comorbidities (84.1%), or MAFLD subtypes (i.e., lean, overweight/obese, and diabetic) (86.1%).This global survey by a collaborative panel of clinical, coding, health management and policy experts, indicates agreement that MAFLD should be coded in ICD-11. The data serves as a foundation for corresponding adjustments in the ICD-11 revision.
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| 7. |
- Bhat, Goutam, et al.
(författare)
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NTIRE 2022 Burst Super-Resolution Challenge
- 2022
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Ingår i: 2022 IEEE/CVF CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION WORKSHOPS (CVPRW 2022). - : IEEE. - 9781665487399 - 9781665487405 ; , s. 1040-1060
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Konferensbidrag (refereegranskat)abstract
- Burst super-resolution has received increased attention in recent years due to its applications in mobile photography. By merging information from multiple shifted images of a scene, burst super-resolution aims to recover details which otherwise cannot be obtained using a simple input image. This paper reviews the NTIRE 2022 challenge on burst super-resolution. In the challenge, the participants were tasked with generating a clean RGB image with 4x higher resolution, given a RAW noisy burst as input. That is, the methods need to perform joint denoising, demosaicking, and super-resolution. The challenge consisted of 2 tracks. Track 1 employed synthetic data, where pixel-accurate high-resolution ground truths are available. Track 2 on the other hand used real-world bursts captured from a handheld camera, along with approximately aligned reference images captured using a DSLR. 14 teams participated in the final testing phase. The top performing methods establish a new state-of-the-art on the burst super-resolution task.
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| 8. |
- Dou, Jin-Hu, et al.
(författare)
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Atomically precise single-crystal structures of electrically conducting 2D metal-organic frameworks
- 2021
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-1122 .- 1476-4660. ; 20, s. 222-228
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Tidskriftsartikel (refereegranskat)abstract
- Electrically conducting 2D metal-organic frameworks (MOFs) have attracted considerable interest, as their hexagonal 2D lattices mimic graphite and other 2D van der Waals stacked materials. However, understanding their intrinsic properties remains a challenge because their crystals are too small or of too poor quality for crystal structure determination. Here, we report atomically precise structures of a family of 2D pi-conjugated MOFs derived from large single crystals of sizes up to 200 mu m, allowing atomic-resolution analysis by a battery of high-resolution diffraction techniques. A designed ligand core rebalances the in-plane and out-of-plane interactions that define anisotropic crystal growth. We report two crystal structure types exhibiting analogous 2D honeycomb-like sheets but distinct packing modes and pore contents. Single-crystal electrical transport measurements distinctively demonstrate anisotropic transport normal and parallel to the pi-conjugated sheets, revealing a clear correlation between absolute conductivity and the nature of the metal cation and 2D sheet packing motif. Two-dimensional MOFs can possess porosity and electrical conductivity but are difficult to grow as single crystals. Here, by balancing in-plane and out-of-plane interactions, single crystals of sizes up to 200 mu m are grown, allowing in-plane transport measurements and atomic-resolution analysis.
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| 9. |
- Kanoni, Stavroula, et al.
(författare)
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Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis.
- 2022
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Ingår i: Genome biology. - : Springer Science and Business Media LLC. - 1474-760X .- 1465-6906 .- 1474-7596. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery.To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N=1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3-5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism.Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.
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| 10. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 11. |
- An, Junghwa, et al.
(författare)
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Permanent Genetic Resources added to Molecular Ecology Resources Database 1 October 2009-30 November 2009
- 2010
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 10:2, s. 404-408
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Tidskriftsartikel (refereegranskat)abstract
- This article documents the addition of 411 microsatellite marker loci and 15 pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Acanthopagrus schlegeli, Anopheles lesteri, Aspergillus clavatus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus oryzae, Aspergillus terreus, Branchiostoma japonicum, Branchiostoma belcheri, Colias behrii, Coryphopterus personatus, Cynogolssus semilaevis, Cynoglossus semilaevis, Dendrobium officinale, Dendrobium officinale, Dysoxylum malabaricum, Metrioptera roeselii, Myrmeciza exsul, Ochotona thibetana, Neosartorya fischeri, Nothofagus pumilio, Onychodactylus fischeri, Phoenicopterus roseus, Salvia officinalis L., Scylla paramamosain, Silene latifo, Sula sula, and Vulpes vulpes. These loci were cross-tested on the following species: Aspergillus giganteus, Colias pelidne, Colias interior, Colias meadii, Colias eurytheme, Coryphopterus lipernes, Coryphopterus glaucofrenum, Coryphopterus eidolon, Gnatholepis thompsoni, Elacatinus evelynae, Dendrobium loddigesii Dendrobium devonianum, Dysoxylum binectariferum, Nothofagus antarctica, Nothofagus dombeyii, Nothofagus nervosa, Nothofagus obliqua, Sula nebouxii, and Sula variegata. This article also documents the addition of 39 sequencing primer pairs and 15 allele specific primers or probes for Paralithodes camtschaticus.
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| 12. |
- Chen, Fei-Jian, et al.
(författare)
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Structure-direction towards the new large pore zeolite NUD-3
- 2021
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 57:2, s. 191-194
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Tidskriftsartikel (refereegranskat)abstract
- The new zeolite NUD-3 possesses a three-dimensional system of large pore channels that is topologically identical to those of ITQ-21 and PKU-14. However, the three zeolites have distinctly different frameworks: a particular single 4-membered ring inside the denser portion of the zeolite is missing in PKU-14, disordered in ITQ-21 and fully ordered in NUD-3. We document these differences and use molecular simulations to unravel the mechanism by which a particular structure directing agent dication, 1,1′-(1,2-phenylenebis(methylene))bis(3-methylimidazolium), is able to orient this inner ring.
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| 13. |
- Jiang, Jian-xin, et al.
(författare)
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Structural and thermal characterization of galactomannans from genus Gleditsia seeds as potential food gum substitutes
- 2011
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Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 91:4, s. 732-737
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Seed galactomannans are preferred hydrocolloids since they are comparatively cheap, non-toxic, eco-friendly and non-polluting during production and application. Galactomannans from seeds of three species of Gleditsia, namely G. sinensis, G. microphylla and G. melanacantha, were characterized in terms of structural and thermal properties. RESULTS: Gleditsia polysaccharides were characterized using both chemical and chromatographic methods, as well as Fourier transform infrared, H-1 nuclear magnetic resonance (NMR) and C-13 NMR spectroscopy, and it was shown that they consist of D-mannopyranose and D-galactopyranose residues. The mannose/galactose (M/G) ratio of galactomannans was 3.25, 3.31 and 2.30, respectively. It was also found that these polysaccharides differ from one another in values of M-w, M-n and polydispersity. X-ray diffraction confirmed the amorphous nature of Gleditsia galactomannans, although G. sinensis galactomannan showed a high crystallinity. Thermal analysis of the galactomannans by differential scanning calorimetry illustrated that their endothermic peaks ranged from 290 to 320 degrees C. CONCLUSION: Gleditsia polysaccharides are neutral galactomannans. The higher value of M/G ratio from G. sinensis and G. microphylla indicates that their gums offer an excellent alternative for locus bean gum. (C) 2011 Society of Chemical Industry
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| 14. |
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| 15. |
- Luo, Zhenghui, et al.
(författare)
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Fine-Tuning Energy Levels via Asymmetric End Groups Enables Polymer Solar Cells with Efficiencies over 17%
- 2020
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Ingår i: Joule. - : CELL PRESS. - 2542-4351. ; 4:6, s. 1236-1247
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Tidskriftsartikel (refereegranskat)abstract
- Generally, it is important to fine-tune the energy levels of donor and acceptor materials in the field of polymer solar cell (PSCs) to achieve a minimal highest occupied molecular orbital (HOMO) energy offset, which yet is still sufficient for charge separation. Based on the high-performance small-molecule acceptor (SMA) of BTP-4F, we modified the end groups of BTP-4F from IC-2F to CPTCN-Cl. It was found that when both end groups were substituted by CPTCN-Cl, the energy level upshift was too large that caused unfavorable energetic alignment, thus poor device performance. By using the strategy of asymmetric end groups, we were able to achieve near optimal energy level match, resulting in higher open-circuit voltage (V-OC) and power conversion efficiency (PCE) compared with those given by the PM6:BTP-4F system. Our strategy can be useful and potentially applied to othermaterial systems for maximizing efficiency of non-fullerene PSCs.
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| 16. |
- Mahajan, Anubha, et al.
(författare)
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Multi-ancestry genetic study of type 2 diabetes highlights the power of diverse populations for discovery and translation
- 2022
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Ingår i: Nature Genetics. - : Springer Nature. - 1061-4036 .- 1546-1718. ; 54:5, s. 560-572
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Tidskriftsartikel (refereegranskat)abstract
- We assembled an ancestrally diverse collection of genome-wide association studies (GWAS) of type 2 diabetes (T2D) in 180,834 affected individuals and 1,159,055 controls (48.9% non-European descent) through the Diabetes Meta-Analysis of Trans-Ethnic association studies (DIAMANTE) Consortium. Multi-ancestry GWAS meta-analysis identified 237 loci attaining stringent genome-wide significance (P < 5 x 10(-9)), which were delineated to 338 distinct association signals. Fine-mapping of these signals was enhanced by the increased sample size and expanded population diversity of the multi-ancestry meta-analysis, which localized 54.4% of T2D associations to a single variant with >50% posterior probability. This improved fine-mapping enabled systematic assessment of candidate causal genes and molecular mechanisms through which T2D associations are mediated, laying the foundations for functional investigations. Multi-ancestry genetic risk scores enhanced transferability of T2D prediction across diverse populations. Our study provides a step toward more effective clinical translation of T2D GWAS to improve global health for all, irrespective of genetic background. Genome-wide association and fine-mapping analyses in ancestrally diverse populations implicate candidate causal genes and mechanisms underlying type 2 diabetes. Trans-ancestry genetic risk scores enhance transferability across populations.
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| 17. |
- Pathak, Surajit, et al.
(författare)
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Association of MicroRNA-652 Expression with Radiation Response of Colorectal Cancer : A Study from Rectal Cancer Patients in a Swedish Trial of Preoperative Radiotherapy
- 2023
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Ingår i: Current Gene Therapy. - : Bentham Science Publishers. - 1566-5232 .- 1875-5631. ; 23:5, s. 356-367
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Tidskriftsartikel (refereegranskat)abstract
- Background: Radiotherapy is a standard adjuvant therapy in patients with progressive rectal cancer, but many patients are resistant to radiotherapy, leading to poor prognosis. Our study identified microRNA-652 (miR-652) value on radiotherapy response and outcome in rectal cancer patients.Methods: miR-652 expression was determined by qPCR in primary rectal cancer from 48 patients with and 53 patients without radiotherapy. The association of miR-652 with biological factors and the prognosis was examined. The biological function of miR-652 was identified through TCGA and GEPIA database searches. Two human colon cancer cell lines (HCT116 p53(+/+) and p53(-/-)) were used for in vitro study. The molecular interactions of miR-652 and tumor suppressor genes were studied through a computational approach.Results: In RT patients, miR-652 expression was significantly decreased in cancers when compared to non-radiotherapy cases (P = 0.002). High miR-652 expression in non-RT patients was with increased apoptosis marker (P = 0.036), ATM (P = 0.010), and DNp73 expression (P = 0.009). High miR-652 expression was related to worse disease-free survival of non-radiotherapy patients, independent of gender, age, tumor stage, and differentiation (P = 0.028; HR = 7.398, 95% CI 0.217-3.786). The biological functional analysis further identified the prognostic value and potential relationship of miR-652 with apoptosis in rectal cancer. miR-652 expression in cancers was negatively related to WRAP53 expression (P = 0.022). After miR-652 inhibition, the estimation of reactive oxygen species, caspase activity, and apoptosis in HCT116 p53(+/+ )cells was significantly increased compared with HCT116 p53(-/-) cells after radiation. The results of the molecular docking analysis show that the miR652-CTNNBL1 and miR652-TP53 were highly stable.Conclusion: Our findings suggest the potential value of miR-652 expression as a marker for the prediction of radiation response and clinical outcome in rectal cancer patients.
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| 18. |
- Schmit, Stephanie L, et al.
(författare)
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Novel Common Genetic Susceptibility Loci for Colorectal Cancer.
- 2019
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 111:2, s. 146-157
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Tidskriftsartikel (refereegranskat)abstract
- Background: Previous genome-wide association studies (GWAS) have identified 42 loci (P < 5 × 10-8) associated with risk of colorectal cancer (CRC). Expanded consortium efforts facilitating the discovery of additional susceptibility loci may capture unexplained familial risk.Methods: We conducted a GWAS in European descent CRC cases and control subjects using a discovery-replication design, followed by examination of novel findings in a multiethnic sample (cumulative n = 163 315). In the discovery stage (36 948 case subjects/30 864 control subjects), we identified genetic variants with a minor allele frequency of 1% or greater associated with risk of CRC using logistic regression followed by a fixed-effects inverse variance weighted meta-analysis. All novel independent variants reaching genome-wide statistical significance (two-sided P < 5 × 10-8) were tested for replication in separate European ancestry samples (12 952 case subjects/48 383 control subjects). Next, we examined the generalizability of discovered variants in East Asians, African Americans, and Hispanics (12 085 case subjects/22 083 control subjects). Finally, we examined the contributions of novel risk variants to familial relative risk and examined the prediction capabilities of a polygenic risk score. All statistical tests were two-sided.Results: The discovery GWAS identified 11 variants associated with CRC at P < 5 × 10-8, of which nine (at 4q22.2/5p15.33/5p13.1/6p21.31/6p12.1/10q11.23/12q24.21/16q24.1/20q13.13) independently replicated at a P value of less than .05. Multiethnic follow-up supported the generalizability of discovery findings. These results demonstrated a 14.7% increase in familial relative risk explained by common risk alleles from 10.3% (95% confidence interval [CI] = 7.9% to 13.7%; known variants) to 11.9% (95% CI = 9.2% to 15.5%; known and novel variants). A polygenic risk score identified 4.3% of the population at an odds ratio for developing CRC of at least 2.0.Conclusions: This study provides insight into the architecture of common genetic variation contributing to CRC etiology and improves risk prediction for individualized screening.
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| 19. |
- Sun, Gang, et al.
(författare)
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Energy-Efficient Provisioning for Service Function Chains to Support Delay-Sensitive Applications in Network Function Virtualization
- 2020
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Ingår i: IEEE Internet of Things Journal. - : IEEE. - 2327-4662. ; 7:7, s. 6116-6131
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Tidskriftsartikel (refereegranskat)abstract
- The efficient deployment of virtual network functions (VNFs) for network service provisioning is key for achieving network function virtualization (NFV); however, most existing studies address only offline or one-off deployments of service function chains (SFCs) while neglecting the dynamic (i.e., online) deployment and expansion requirements. In particular, many methods of energy/resource cost reduction are achieved by merging VNFs. However, the energy waste and device wear for large-scale collections of servers (e.g., cloud networks and data centers) caused by sporadic request updating are ignored. To solve these problems, we propose an energy-aware routing and adaptive delayed shutdown (EAR-ADS) algorithm for dynamic SFC deployment, which includes the following features. 1) Energy-aware routing (EAR): By considering a practical deployment environment, a flexible solution is developed based on reusing open servers and selecting paths with the aims of balancing energy and resources and minimizing the total cost. 2) Adaptive delayed shutdown (ADS): The delayed shutdown time of the servers can be flexibly adjusted in accordance with the usage of each device in each time slot, thus eliminating the no-load wait time of the servers and frequent on/off switching. Therefore, EAR-ADS can achieve dual energy savings by both decreasing the number of open servers and reducing the idle/switching energy consumption of these servers. Simulation results show that EAR-ADS not only minimizes the cost of energy and resources but also achieves an excellent success rate and stability. Moreover, EAR-ADS is efficient compared with an improved Markov algorithm (SAMA), reducing the average deployment time by more than a factor of 40.
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| 20. |
- Sun, L., et al.
(författare)
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Room-Temperature Quantitative Quantum Sensing of Lithium Ions with a Radical-Embedded Metal-Organic Framework
- 2022
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:41, s. 19008-19016
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Tidskriftsartikel (refereegranskat)abstract
- Recent advancements in quantum sensing have sparked transformative detection technologies with high sensitivity, precision, and spatial resolution. Owing to their atomic-level tunability, molecular qubits and ensembles thereof are promising candidates for sensing chemical analytes. Here, we show quantum sensing of lithium ions in solution at room temperature with an ensemble of organic radicals integrated in a microporous metal-organic framework (MOF). The organic radicals exhibit electron spin coherence and microwave addressability at room temperature, thus behaving as qubits. The high surface area of the MOF promotes accessibility of the guest analytes to the organic qubits, enabling unambiguous identification of lithium ions and quantitative measurement of their concentration through relaxometric and hyperfine spectroscopic methods based on electron paramagnetic resonance (EPR) spectroscopy. The sensing principle presented in this work is applicable to other metal ions with nonzero nuclear spin.
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| 21. |
- Wang, Jian, et al.
(författare)
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Novel Mechanism of Macrophage-Mediated Metastasis Revealed in a Zebrafish Model of Tumor Development
- 2015
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Ingår i: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 75:2, s. 306-315
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Tidskriftsartikel (refereegranskat)abstract
- Cancer metastasis can occur at early stages of tumor development due to facilitative alterations in the tumor microenvironment. Although imaging techniques have considerably improved our understanding of metastasis, early events remain challenging to study due to the small numbers of malignant cells involved that are often undetectable. Using a novel zebrafish model to investigate this process, we discovered that tumor-associated macrophages (TAM) acted to facilitate metastasis by binding tumor cells and mediating their intravasation. Mechanistic investigations revealed that IL6 and TNF alpha promoted the ability of macrophages to mediate this step. M2 macro-phages were particularly potent when induced by IL4, IL10, and TGF beta. In contrast, IFN gamma-lipopolysaccharide-induced M1 macrophages lacked the capability to function in the same way in the model. Confirming these observations, we found that human TAM isolated from primary breast, lung, colorectal, and endometrial cancers exhibited a similar capability in invasion and metastasis. Taken together, our work shows how zebrafish can be used to study how host contributions can facilitate metastasis at its earliest stages, and they reveal a new macrophage-dependent mechanism of metastasis with possible prognostic implications.
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| 22. |
- Wei, Xiao-Ping, et al.
(författare)
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Investigations on electronic, Fermi surface, Curie temperature and optical properties of Zr2CoAl
- 2017
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Ingår i: Journal of Solid State Chemistry. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0022-4596 .- 1095-726X. ; 247, s. 97-104
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Tidskriftsartikel (refereegranskat)abstract
- Using full-potential local-orbital minimum-basis along with spin-polarized relativistic Korringa-Kohn-Rostoker methods, we study the electronic, Fermi surface, Curie temperature and optical properties of Zr2CoAl alloy. The alloy with Li2AgSb and Cu2MnAl structures are compared in terms of magnetic properties, and the electronic structures in two structures are also discussed. According to the calculated electronic states, it finds that the Zr2CoAl with Li2AgSb structure is half-metallic ferromagnet with an integral magnetic moment of 2.00 mu(beta), meanwhile we also notice the d-d and p-d hybridizations are responsible for the formation of minority-spin gap, furthermore, the fat-bands are applied to discuss the mixture between d and p electrons in the vicinity of the Fermi level. The Fermi surfaces related to the valence bands are constructed, and it is found that the spin-up valence bands 26, 27 and 28 across the Fermi energy dominate the nature of electrons. By mapping the system onto a Heisenberg Hamiltonian, we obtain the exchange coupling parameters, and observe that the Zr(A)-Co(C) and Zr(A)-Zr(B) interactions provide a major contribution for exchange interactions. Based on the calculated exchange coupling parameters, the Curie temperature is estimated to be 287.86 K at equilibrium, and also the dependence of Curie temperature on lattice constant related to the tunable Curie temperature in Zr2CoAl alloy is studied. Finally, we report the optical properties of Zr2CoAl alloy, and present the photon energy dependence of the absorption, the optical conductivity and the loss function.
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| 23. |
- Zhang, Wei, et al.
(författare)
-
Knockdown of MMP-7 inhibits cell proliferation and enhances sensitivity to 5-fluorouracil and X-ray irradiation in colon cancer cells
- 2014
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Ingår i: Clinical and Experimental Medicine (Testo stampato). - : Springer Verlag (Germany). - 1591-8890 .- 1591-9528. ; 14:1, s. 99-106
-
Tidskriftsartikel (refereegranskat)abstract
- The role of matrix metalloproteinase-7 (MMP-7) in the pathogenesis of colon cancer is not understood thoroughly. Previous studies from our group have shown that the expression levels of MMP-7 were highly elevated in colorectal cancer patient specimens and were correlated with Dukes Staging, histological differentiation grade and CEA level. The goal of this study was to investigate the cellular impact of MMP-7 in colon cancer. In this study, we used the SW480 colon cancer cell lines of MMP-7 knockdown by lentivirus-mediated RNA interference as a model system to investigate the impact of MMP-7 on cell proliferation and sensitivity to 5-Fluorouracil (5-FU) and X-ray irradiation (IR). Cell proliferation and sensitivity to 5-FU and IR were measured by MTT assay and colony formation assay. Cell cycle was evaluated by flow cytometry. We showed that the down regulation of MMP-7 inhibits colon cancer cell proliferation and sensitizes tumour cells to 5-FU and IR (P less than 0.05). Decreased MMP-7 expression in SW480 cells by RNA interference triggered cell cycle arrest at G1 phase (P less than 0.05). Down regulation of MMP-7 may inhibit the cell proliferation of colon cancer cells and increase tumour cells sensitivity to radiotherapy and chemotherapy. RNAi-mediated silencing of MMP-7 may represent a powerful therapeutic approach for controlling human colorectal cancer growth.
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| 24. |
- Zhao, Guang-Jiu, et al.
(författare)
-
Photoinduced intramolecular charge transfer and S-2 fluorescence in thiophene-pi-conjugated donor-acceptor systems : Experimental and TDDFT studies
- 2008
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 14:23, s. 6935-6947
-
Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical methods were used to study newly synthesized thiophene-pi-cojugated donor-acceptor compounds, which were found to exhibit efficient intramolecular charge-transfer emission in polar solvents with relatively large Stokes shifts and strong solvatochromism. To gain insight into the solvatochromic behavior of these compounds, the dependence of the spectra on solvent polarity was studied on the basis of Lippert-Mataga models. We found that intramolecular charge transfer in these donor-acceptor systems is significantly dependent on the electron-with-drawing substituents at the thienyl 2-position. The dependence of the absorption and emission spectra of these compounds in methanol on the concentration of trifluoroacetic acid was used to confirm intramolecular charge-tranfer emission. Moreover, the calculated absorption and emission energies, which are in accordance with the experimental values, suggested that fluorescence can be emitted from different geometric confirmations. In addition, a novel S-2 fluorescence phenomenon for some of these compounds was also be observed. The fluorescence excitation spectra were used to confirm the S-2 fluorescence. We demonstrate that S-2 fluorescence can be explained by the calculated energy gap between the S-2 and S-1 states of these molecules. Furthermore, nonlinear optical behavior of the thiophene-pi-conjugated compound with diethylcyanomethylphosphonate substituents was predicted in theory.
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| 25. |
- Zhou, Shun-Fan, et al.
(författare)
-
Membrane-associated transcription factor peptidase, site-2 protease, antagonizes ABA signaling in Arabidopsis
- 2015
-
Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 208:1, s. 188-197
-
Tidskriftsartikel (refereegranskat)abstract
- Abscisic acid plays important roles in maintaining seed dormancy while gibberellins (GA) and other phytohormones antagonize ABA to promote germination. However, how ABA signaling is desensitized during the transition from dormancy to germination is still poorly understood. We functionally characterized the role of membrane-associated transcription factor peptidase, site-2 protease (S2P), in ABA signaling during seed germination in Arabidopsis. Genetic analysis showed that loss-of-function of S2P conferred high ABA sensitivity during seed germination, and expression of the activated form of membrane-associated transcription factor bZIP17, in which the transmembrane domain and endoplasmic reticulum (ER) lumen-facing C-terminus were deleted, in the S2P mutant rescued its ABA-sensitive phenotype. MYC and green fluorescent protein (GFP)-tagged bZIP17 were processed and translocated from the ER to the nucleus in response to ABA treatment. Furthermore, genes encoding negative regulators of ABA signaling, such as the transcription factor ATHB7 and its target genes HAB1, HAB2, HAI1 and AHG3, were up-regulated in seeds of the wild-type upon ABA treatment; this up-regulation was impaired in seeds of S2P mutants. Our results suggest that S2P desensitizes ABA signaling during seed germination through regulating the activation of the membrane-associated transcription factor bZIP17 and therefore controlling the expression level of genes encoding negative regulators of ABA signaling.
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| 26. |
- Bisgin, Atil, et al.
(författare)
-
Interaction of CD200 Overexpression on Tumor Cells with CD200R1 Overexpression on Stromal Cells: An Escape from the Host Immune Response in Rectal Cancer Patients
- 2019
-
Ingår i: Journal of Oncology. - : HINDAWI LTD. - 1687-8450 .- 1687-8469. ; 2019
-
Tidskriftsartikel (refereegranskat)abstract
- CD200 imparts an immunoregulatory signal through its receptor, CD200R1, leading to the suppression of tumor specific immunity. The mechanism of CD200:CD200R1 signaling pathway is still uncertain. Our aim was to investigate the expression and localization of CD200 and its receptor CD200R1 and their clinical significance in rectal cancer patients. We examined the immunohistochemical expressions and localizations of CD200 and CD200R1 in 140 rectal cancer patients. Among the patients, 79 underwent the preoperative radiotherapy and the others were untreated prior to the surgery. In addition, 121 matched normal rectal mucosa samples were evaluated. The results of immunohistochemical analysis showed a strikingly high level of CD200 in tumor cells (p=0.001) and CD200R1 expression in normal mucosal epithelium and stromal cells. Importantly, CD200R1 was overexpressed in stromal cells of the metastatic cancer patients compared to patients without metastases (p=0.002). More than that, 87% of metastatic patients had a phenotype of upregulated CD200 in tumor cells accompanied by overexpressed CD200R1 in stromal cells. In addition, low levels of CD200 were correlated with improved overall survival in untreated patients. We showed that tumor-stroma communication through CD200 and its receptor interaction is selected in patients with high risk of relapse. High levels of these molecules support instigation of the far and local metastatic nest that provides solid ground for metastasis. Our current data also disclose a mechanism by which CD200:CD200R1 affects tumor progression and may strengthen the feasibility of targeting CD200 or CD200R1 as anticancer strategy.
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| 27. |
- Byun, Jinyoung, et al.
(författare)
-
Cross-ancestry genome-wide meta-analysis of 61,047 cases and 947,237 controls identifies new susceptibility loci contributing to lung cancer
- 2022
-
Ingår i: Nature Genetics. - : Nature Research. - 1061-4036 .- 1546-1718. ; 54:8, s. 1167-1177
-
Tidskriftsartikel (refereegranskat)abstract
- To identify new susceptibility loci to lung cancer among diverse populations, we performed cross-ancestry genome-wide association studies in European, East Asian and African populations and discovered five loci that have not been previously reported. We replicated 26 signals and identified 10 new lead associations from previously reported loci. Rare-variant associations tended to be specific to populations, but even common-variant associations influencing smoking behavior, such as those with CHRNA5 and CYP2A6, showed population specificity. Fine-mapping and expression quantitative trait locus colocalization nominated several candidate variants and susceptibility genes such as IRF4 and FUBP1. DNA damage assays of prioritized genes in lung fibroblasts indicated that a subset of these genes, including the pleiotropic gene IRF4, potentially exert effects by promoting endogenous DNA damage.
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| 28. |
- Cao, Wei, et al.
(författare)
-
Ionic organic cage-encapsulated metal clusters for switchable catalysis
- 2021
-
Ingår i: Cell Reports Physical Science. - : Elsevier BV. - 2666-3864. ; 2:9
-
Tidskriftsartikel (refereegranskat)abstract
- The capability to build up stable, switchable catalysts for complex artificial systems that can mimic the responsiveness of biological systems to multiple triggers is highly desirable and challenging. Herein, we engineer such a system by physically locking catalytically active metal clusters (MCs) inside individual cationic molecular organic cages (I-Cages), where the responsive and task-specific counteranions of I-Cages impart MCs with a programmable gating effect. This allows for precise spatial and temporal control over chemical reactions by regulating accessibility of reagents to the MC sites. Following this strategy, we have successfully tailored catalytic activity of a series of model catalysis (e.g., methanolysis of ammonia borane, and the reduction of 4-nitroaniline) by employing light and pH stimuli, as well as their combination, for programmable-activity control.
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| 29. |
- Chen, Geng, et al.
(författare)
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Heisenberg-scaling measurement of the single-photon Kerr non-linearity using mixed states
- 2018
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Improving the precision of measurements is a significant scientific challenge. Previous works suggest that in a photon-coupling scenario the quantum fisher information shows a quantum-enhanced scaling of N-2, which in theory allows a better-than-classical scaling in practical measurements. In this work, utilizing mixed states with a large uncertainty and a post-selection of an additional pure system, we present a scheme to extract this amount of quantum fisher information and experimentally attain a practical Heisenberg scaling. We performed a measurement of a single-photon's Kerr non-linearity with a Heisenberg scaling, where an ultra-small Kerr phase of. 6 x 10(-8) rad was observed with a precision of similar or equal to 3.6 x 10(-10) rad. From the use of mixed states, the upper bound of quantum fisher information is improved to 2N(2). Moreover, by using an imaginary weak-value the scheme is robust to noise originating from the self-phase modulation.
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| 30. |
- Chen, Tianyang, et al.
(författare)
-
Dimensionality Modulates Electrical Conductivity in Compositionally Constant One-, Two-, and Three-Dimensional Frameworks
- 2022
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:12, s. 5583-5593
-
Tidskriftsartikel (refereegranskat)abstract
- We reveal here the construction of Ni-based metal-organic frameworks (MOFs) and conjugated coordination polymers (CCPs) with different structural dimensionalities, including closely pi-stacked 1D chains (Ni-1D), aggregated 2D layers (Ni-2D), and a 3D framework (Ni-3D), based on 2,3,5,6-tetraamino-1,4-hydroquinone (TAHQ) and its various oxidized forms. These materials have the same metal-ligand composition but exhibit distinct electronic properties caused by different dimensionalities and supramolecular interactions between SBUs, ligands, and structural motifs. The electrical conductivity of these materials spans nearly 8 orders of magnitude, approaching 0.3 S/cm.
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| 31. |
- Chen, Xiaoyun, et al.
(författare)
-
Invasiveness and metastasis of retinoblastoma in an orthotopic zebrafish tumor model
- 2015
-
Ingår i: Scientific Reports. - : Nature Publishing Group: Open Access Journals - Option C / Nature Publishing Group. - 2045-2322. ; 5:10351
-
Tidskriftsartikel (refereegranskat)abstract
- Retinoblastoma is a highly invasive malignant tumor that often invades the brain and metastasizes to distal organs through the blood stream. Invasiveness and metastasis of retinoblastoma can occur at the early stage of tumor development. However, an optimal preclinical model to study retinoblastoma invasiveness and metastasis in relation to drug treatment has not been developed. Here, we developed an orthotopic zebrafish model in which retinoblastoma invasion and metastasis can be monitored at a single cell level. We took the advantages of immune privilege and transparent nature of developing zebrafish embryos. Intravitreal implantation of color-coded retinoblastoma cells allowed us to kinetically monitor tumor cell invasion and metastasis. Further, interactions between retinoblastoma cells and surrounding microvasculatures were studied using a transgenic zebrafish that exhibited green fluorescent signals in blood vessels. We discovered that tumor cells invaded neighboring tissues and blood stream when primary tumors were at the microscopic sizes. These findings demonstrate that retinoblastoma metastasis occurs at the early stage and antiangiogenic drugs such as Vegf morpholino and sunitinib could potentially interfere with tumor invasiveness and metastasis. Thus, this orthotopic retinoblastoma model offers a new and unique opportunity to study the early events of tumor invasion, metastasis and drug responses.
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| 32. |
- Dai, Cheng-ren, et al.
(författare)
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Composition and temperature dependence of alpha(2) phase decomposition in high Nb-containing lamellar gamma-TiAl alloys : Experiments and first-principles calculations
- 2021
-
Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 221, s. 117419-
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reports an experimental and theoretical study of composition and temperature dependence of alpha(2) phase decomposition in lamellar gamma-Ti -(43 similar to 47)Al-(4 similar to 10)Nb alloys. The alpha(2) phase decomposes to nano-sized orthorhombic (O) phase in the alloys (the Nb content >= 5.5 at.%) at temperatures of 550 similar to 750 degrees C. The transformation temperature decreases with increasing the Al content, but increases with increasing the Nb content. The Nb partitioning coefficient between O and alpha(2) typically equals to 2, and decreases with increasing the Al content and temperature, confirming that the O phase transformation is controlled by Nb diffusion. The alpha(2) to omega(0) phase transformation takes place in the alloys (the Nb content > 7 at.%) at 800 degrees C. The blocky omega(0) phase is enriched in Nb and the Nb partitioning coefficient between omega(0) and alpha(2) is about 1.3, indicating that the omega(0) phase transformation is also related to Nb diffusion. The pseudo-binary phase diagram calculated by first-principles correctly predicts the alpha(2) to O phase transformation at temperature below 750 degrees C and alpha(2) to omega(0) phase transformation at temperature above 750 degrees C in the alloys. Since the alpha(2) phase is unstable thermodynamically at intermediate temperature, such kinds of alpha(2) to O and omega(0) phase transformations are considered necessarily for design of high Nb-containing gamma-TiAl alloys.
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| 33. |
- Ding, Huimin, et al.
(författare)
-
An AIEgen-based 3D covalent organic framework for white light-emitting diodes
- 2018
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- The design and synthesis of three-dimensional covalent organic frameworks (3D COFs) have still been considered as a big challenge. Here we report the design and synthesis of an AIEgen-based 3D COF (3D-TPE-COF), with a high surface area (1084 m(2)g(-1)). According to powder X-ray diffraction and continuous rotation electron diffraction analyses, 3D-TPE-COF is identified to adopt a seven-fold interpenetrated pts topology. Interestingly, 3D-TPE-COF emits yellow fluorescence upon excitation, with a photoluminescence quantum yield of 20%. Moreover, by simply coating 3D-TPE-COF onto a commercial blue light-emitting diode (LED), a prototype white LED (WLED) under continuously driving without degradation for 1200 h was demonstrated. The present work suggests the possibility of using COF materials for stable WLEDs, which will greatly inspire us to design and synthesize fluorescent 3D COFs and facilitate the development of COF-based WLEDs in future.
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| 34. |
- Du, Jian, et al.
(författare)
-
2D materials for solar fuels via artificial photosynthesis
- 2022
-
Ingår i: National Science Review. - : Oxford University Press (OUP). - 2095-5138 .- 2053-714X. ; 9:5
-
Tidskriftsartikel (refereegranskat)abstract
- To accelerate the chemical processes of water splitting, CO2 reduction and N2 fixation in artificial photosynthetic systems, various strategies to improve the properties of 2D materials with catalysts are highlighted in this perspective.
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| 35. |
- Du, Jian, et al.
(författare)
-
Cu3P/CuO Core-Shell Nanorod Arrays as High-Performance Electrocatalysts for Water Oxidation
- 2018
-
Ingår i: ChemElectroChem. - : Wiley-VCH Verlagsgesellschaft. - 2196-0216. ; 5:15, s. 2064-2068
-
Tidskriftsartikel (refereegranskat)abstract
- Earth-abundant transition-metal-based oxides are potential candidates to replace the state-of-the-art noble-metal-based oxygen evolution catalysts (OECs) such as IrO2 and RuO2. Despite the low cost and large abundance, copper-based OER catalysts have been less frequently studied, mainly owing to the low electrical conductivity of copper oxides that results in large overpotential and sluggish kinetics for oxygen evolution. We report here the insitu fabrication of semi-metallic Cu3P nanorod arrays on commercial copper foam via a template approach; the resulting self-supported core-shell Cu-Cu3P/CuO electrode has the merits of high electrical conductivity, large active area, and short diffusion paths for electrolyte and evolved oxygen, exhibiting a low overpotential of 315mV and high durability over 50h at a current density of 10mAcm(-2) for OER in 1.0 M KOH. The remarkable OER performance reported here is not only superior to that of analogous Cu-CuO foam electrode, but also outperforms those of copper-based OER electrocatalysts in the literature.
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| 36. |
- Du, Jian, et al.
(författare)
-
Iron carbonate hydroxide templated binary metal-organic frameworks for highly efficient electrochemical water oxidation
- 2019
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 55:98, s. 14773-14776
-
Tidskriftsartikel (refereegranskat)abstract
- Metal-organic frameworks (MOFs) are promising catalysts for electrochemical reactions. Herein, self-supported NiFe-MOF nanoplates grown on Ni foam (NF) were prepared with iron carbonate hydroxide nanosheets (FeCH NSs) as a semisacrificial template and evaluated for the electrocatalytic oxygen evolution reaction (OER). In this approach, the porous FeCH NSs not only serve as the iron source of NiFe-MOF, but also slow down the leaching of Ni ions from the substrate, thus playing a unique role in regulating the morphology of NiFe-MOF with reduced thickness and sizes, enabling rapid electron transfer and mass transport. The resultant NiFe-MOF/FeCH-NF electrode showed higher activity than FeCH template-free electrodes and superior OER performance over other MOF based binder-free OER electrodes. A current density of 10 mA cm(-2) was obtained at a low overpotential of 200 mV with excellent durability in alkaline solution. Raman and TEM measurements reveal the partial transformation of NiFe-MOF to hydroxide during water oxidation.
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| 37. |
- Du, Jian, et al.
(författare)
-
Iron-Salen Complex and Co2+ Ion-Derived Cobalt-Iron Hydroxide/Carbon Nanohybrid as an Efficient Oxygen Evolution Electrocatalyst
- 2019
-
Ingår i: Advanced Science. - : WILEY. - 2198-3844. ; 6:12
-
Tidskriftsartikel (refereegranskat)abstract
- Metal-salen complexes are widely used as catalysts in numerous fundamental organic transformation reactions. Here, CoFe hydroxide/carbon nanohybrid is reported as an efficient oxygen evolution electrocatalyst derived from the in situ formed molecular Fe-salen complexes and Co2+ ions at a low temperature of 160 degrees C. It has been evidenced that Fe-salen as a molecular precursor facilitates the confined-growth of metal hydroxides, while Co2+ plays a critical role in catalyzing the transformation of organic ligand into nanocarbons and constitutes an essential component for CoFe hydroxide. The resulting Co1.2Fe/C hybrid material requires an overpotential of 260 mV at a current density of 10 mA cm(-2) with high durability. The high activity is contributed to uniform distribution of CoFe hydroxides on carbon layer and excellent electron conductivity caused by intimate contact between metal and nanocarbon. Given the diversity of molecular precursors, these results represent a promising approach to high-performance carbon-based water splitting catalysts.
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| 38. |
- Du, Jian, et al.
(författare)
-
Metal-organic frameworks and their derivatives as electrocatalysts for the oxygen evolution reaction
- 2021
-
Ingår i: Chemical Society Reviews. - : Royal Society of Chemistry (RSC). - 0306-0012 .- 1460-4744. ; 50:4, s. 2663-2695
-
Forskningsöversikt (refereegranskat)abstract
- Electrochemical water splitting is an appealing and promising approach for energy conversion and storage. As a key half-reaction of electricity-driven water splitting, the oxygen evolution reaction (OER) is a sluggish process due to the transfer of four protons and four electrons. Therefore, development of low-cost and robust OER electrocatalysts is of great importance for improving the efficiency of water splitting. Based on the merits of high surface area, rich pore structure, diverse composition and well-defined metal centers, metal-organic frameworks (MOFs) and their derivatives have been widely exploited as OER electrocatalysts. Herein, the current progress on MOFs and their derivatives for OER electrolysis is summarized, highlighting the design principle, synthetic methods and performance for MOF-based materials. In addition, the structure-performance relationships of MOFs and their derivatives toward the OER are discussed, providing valuable insights into rationally developing OER catalysts with high efficiency. The current scientific and technological challenges and future perspectives towards the purpose of sustainable industrial applications are addressed at the end.
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| 39. |
- Etman, Ahmed S., et al.
(författare)
-
A one-step water based strategy for synthesizing hydrated vanadium pentoxide nanosheets from VO2(B) as free-standing electrodes for lithium battery applications
- 2016
-
Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 4:46, s. 17988-18001
-
Tidskriftsartikel (refereegranskat)abstract
- The synthesis of two dimensional (2D) materials from transition metal oxides, chalcogenides, and carbides mostly involve multiple exfoliation steps in which hazardous solvents and reagents are used. In this study, hydrated vanadium pentoxide (V2O5 center dot nH(2)O) nanosheets with a thickness of a few nanometers were prepared via a facile environmentally friendly water based exfoliation technique. The exfoliation process involved refluxing the precursor, vanadium dioxide (VO2(B)), in water for a few days at 60 degrees C. The proposed exfoliation mechanism is based on the intercalation/insertion of water molecules into the VO2(B) crystals and the subsequent cleavage of the covalent bonds holding the layers of VO2(B) together. The thermal and chemical analyses showed that the approximate chemical composition of the nanosheets is H0.4V2O5 center dot 0.55H(2)O, and the percentage of V-V content to that of V-IV in the nanosheets is about 80(3)% to 20(3)%. The exfoliated aqueous suspension of the V2O5 center dot 0.55H(2)O nanosheets was successfully deposited onto multi-walled carbon nanotube (MW-CNT) paper to form free-standing electrodes with a thickness of the V2O5 center dot 0.55H(2)O layer ranging between 45 and 4 mu m. A series of electrochemical tests were conducted on the electrodes to determine the cyclability and rate capability of lithium insertion into V2O5 center dot 0.55H(2)O nanosheets. The electrodes with the thinnest active material coating (similar to 4 mu m) delivered gravimetric capacities of up to 480 and 280 mA h g(-1) when cycled at current densities of 10 and 200 mA g(-1), respectively.
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| 40. |
- Etman, Ahmed S., et al.
(författare)
-
A one-step water based strategy for synthesizing hydrated vanadium pentoxide nanosheets from VO2(B) as free-standing electrodes for lithium battery applications
- 2016
-
Ingår i: Journal of Materials Chemistry A. - 2050-7488. ; 4:46, s. 17988-18001
-
Tidskriftsartikel (refereegranskat)abstract
- The synthesis of two dimensional (2D) materials from transition metal oxides, chalcogenides, and carbides mostly involve multiple exfoliation steps in which hazardous solvents and reagents are used. In this study, hydrated vanadium pentoxide (V2O5[middle dot]nH2O) nanosheets with a thickness of a few nanometers were prepared via a facile environmentally friendly water based exfoliation technique. The exfoliation process involved refluxing the precursor, vanadium dioxide (VO2(B)), in water for a few days at 60 [degree]C. The proposed exfoliation mechanism is based on the intercalation/insertion of water molecules into the VO2(B) crystals and the subsequent cleavage of the covalent bonds holding the layers of VO2(B) together. The thermal and chemical analyses showed that the approximate chemical composition of the nanosheets is H0.4V2O5[middle dot]0.55H2O, and the percentage of VV content to that of VIV in the nanosheets is about 80(3)% to 20(3)%. The exfoliated aqueous suspension of the V2O5[middle dot]0.55H2O nanosheets was successfully deposited onto multi-walled carbon nanotube (MW-CNT) paper to form free-standing electrodes with a thickness of the V2O5[middle dot]0.55H2O layer ranging between 45 and 4 [small mu ]m. A series of electrochemical tests were conducted on the electrodes to determine the cyclability and rate capability of lithium insertion into V2O5[middle dot]0.55H2O nanosheets. The electrodes with the thinnest active material coating ([similar]4 [small mu ]m) delivered gravimetric capacities of up to 480 and 280 mA h g-1 when cycled at current densities of 10 and 200 mA g-1, respectively.
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| 41. |
- Fan, Zheyong, et al.
(författare)
-
GPUMD: A package for constructing accurate machine-learned potentials and performing highly efficient atomistic simulations
- 2022
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 1089-7690 .- 0021-9606. ; 157:11
-
Tidskriftsartikel (refereegranskat)abstract
- We present our latest advancements of machine-learned potentials (MLPs) based on the neuroevolution potential (NEP) framework introduced in Fan et al. [Phys. Rev. B 104, 104309 (2021)] and their implementation in the open-source package gpumd. We increase the accuracy of NEP models both by improving the radial functions in the atomic-environment descriptor using a linear combination of Chebyshev basis functions and by extending the angular descriptor with some four-body and five-body contributions as in the atomic cluster expansion approach. We also detail our efficient implementation of the NEP approach in graphics processing units as well as our workflow for the construction of NEP models and demonstrate their application in large-scale atomistic simulations. By comparing to state-of-the-art MLPs, we show that the NEP approach not only achieves above-average accuracy but also is far more computationally efficient. These results demonstrate that the gpumd package is a promising tool for solving challenging problems requiring highly accurate, large-scale atomistic simulations. To enable the construction of MLPs using a minimal training set, we propose an active-learning scheme based on the latent space of a pre-trained NEP model. Finally, we introduce three separate Python packages, viz., gpyumd, calorine, and pynep, that enable the integration of gpumd into Python workflows.
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| 42. |
- Gao, Chao, et al.
(författare)
-
Isostructural Three-Dimensional Covalent Organic Frameworks
- 2019
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 58:29, s. 9770-9775
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, we reported the designed synthesis of three isostructural three-dimensional covalent organic frameworks (3D COFs) with -H, -Me, or -F substituents, which have similar crystallinity and topology. Their crystal structures were determined by continuous rotation electron diffraction (cRED), and all three 3D COFs were found to adopt a fivefold interpenetrated pts topology. More importantly, the resolution of these cRED datasets reached up to 0.9-1.0 angstrom, enabling the localization of all non-hydrogen atomic positions in a COF framework directly by 3D ED techniques for the first time. In addition, the precise control of the pore environments through the use of different functional groups led to different selectivities for CO2 over N-2. We have thus confirmed that polycrystalline COFs can be definitely studied to the atomic level as other materials, and this study should also inspire the design and synthesis of 3D COFs with tailored pore environments for interesting applications.
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| 43. |
- Gao, Chao, et al.
(författare)
-
Redox-triggered switching in three-dimensional covalent organic frameworks
- 2020
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The tuning of molecular switches in solid state toward stimuli-responsive materials has attracted more and more attention in recent years. Herein, we report a switchable three-dimensional covalent organic framework (3D COF), which can undergo a reversible transformation through a hydroquinone/quinone redox reaction while retaining the crystallinity and porosity. Our results clearly show that the switching process gradually happened through the COF framework, with an almost quantitative conversion yield. In addition, the redox-triggered transformation will form different functional groups on the pore surface and modify the shape of pore channel, which can result in tunable gas separation property. This study strongly demonstrates 3D COFs can provide robust platforms for efficient tuning of molecular switches in solid state. More importantly, switching of these moieties in 3D COFs can remarkably modify the internal pore environment, which will thus enable the resulting materials with interesting stimuli-responsive properties. Tuning of molecular switches in solid state toward stimuli-responsive materials attracted attention in recent years but has not yet been realized in three-dimensional (3D) covalent organic frameworks (COFs). Herein, the authors demonstrate a stable and switchable 3D COF which undergoes reversible transformation through a hydroquinone/quinone redox reaction.
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| 44. |
- Gao, Chao, et al.
(författare)
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Twist Building Blocks from Planar to Tetrahedral for the Synthesis of Covalent Organic Frameworks
- 2020
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Ingår i: Journal of the American Chemical Society. - 0002-7863 .- 1520-5126. ; 142:8, s. 3718-3723
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Tidskriftsartikel (refereegranskat)abstract
- Rational construction of covalent organic frameworks (COFs) with novel structures still remains a challenge. Herein, we report the designed synthesis of two COFs, 2D-BPTA-COF and 3D-BMTA-COF, starting from biphenyl-based precursors but with different groups at the ortho positions. Both COFs exhibited high crystallinity and large surface area, and interestingly, 2D-BPTA-COF crystallizes into 2D sheets with AB stacking mode while 3D-BMTA-COF adopts a 7-fold interpenetrated structure with pts topology. This structural difference could be ascribed to the introduction of methyl groups in the building blocks, as the dihedral angle of biphenyl rings in 2D-BPTA-COF is similar to 0 degrees while in 3D-BMTA-COF it is similar to 60 degrees. Therefore, it is possible to synthesize COFs with different structures by twisting building blocks from planar to tetrahedral with steric hindrance. We believe this result represents a general and straightforward way to expand the diversity of tetrahedral nodes for constructing 3D COFs in the future, and moreover, a new tetrahedral node for constructing 3D COFs is now available.
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| 45. |
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| 46. |
- Gao, Xueshan, et al.
(författare)
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Mitochondrial DNA Damage in Iron Overload
- 2009
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Ingår i: JOURNAL OF BIOLOGICAL CHEMISTRY. - 0021-9258. ; 284:8, s. 4767-4775
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Tidskriftsartikel (refereegranskat)abstract
- Chronic iron overload has slow and insidious effects on heart, liver, and other organs. Because iron-driven oxidation of most biologic materials (such as lipids and proteins) is readily repaired, this slow progression of organ damage implies some kind of biological "memory." We hypothesized that cumulative iron-catalyzed oxidant damage to mtDNA might occur in iron overload, perhaps explaining the often lethal cardiac dysfunction. Real time PCR was used to examine the " intactness" of mttDNA in cultured H9c2 rat cardiac myocytes. After 3 -5 days exposure to high iron, these cells exhibited damage to mtDNA reflected by diminished amounts of near full-length 15.9-kb PCR product with no change in the amounts of a 16.1-kb product from a nuclear gene. With the loss of intact mtDNA, cellular respiration declined and mRNAs for three electron transport chain subunits and 16 S rRNA encoded by mtDNA decreased, whereas no decrements were found in four subunits encoded by nuclear DNA. To examine the importance of the interactions of iron with metabolically generated reactive oxygen species, we compared the toxic effects of iron in wild-type and rhoo cells. In wild-type cells, elevated iron caused increased production of reactive oxygen species, cytostasis, and cell death, whereas the rhoo cells were unaffected. We conclude that long-term damage to cells and organs in iron-overload disorders involves interactions between iron and mitochondrial reactive oxygen species resulting in cumulative damage to mtDNA, impaired synthesis of respiratory chain subunits, and respiratory dysfunction.
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| 47. |
- Gao, Xueshan, et al.
(författare)
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Mitochondrial dysfunction may explain the cardiomyopathy of chronic iron overload
- 2010
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Ingår i: Free Radical Biology & Medicine. - : Elsevier Science B.V., Amsterdam.. - 0891-5849 .- 1873-4596. ; 49:3, s. 401-407
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Tidskriftsartikel (refereegranskat)abstract
- In patients with hemochromatosis, cardiac dysfunction may appear years after they have reached a state of iron overload. We hypothesized that cumulative iron-catalyzed oxidant damage to mitochondrial DNA (mtDNA) might explain the cardiomyopathy of chronic iron overload. Mice were given repetitive injections of iron dextran for a total of 4 weeks after which the iron-loaded mice had elevated cardiac iron, modest cardiac hypertrophy, and cardiac dysfunction. OCR amplification of near-full-length (similar to 16 kb) mtDNA revealed greater than50% loss of full-length product, whereas amounts of a OCR product of a nuclear gene (13 kb region of beta globin) were unaffected. Quantitative rtPCR analyses revealed 60-70% loss of mRNA for proteins encoded by mtDNA with no change in mRNA abundance for nuclear-encoded respiratory subunits. These changes coincided with proportionate reductions in complex I and IV activities and decreased respiration of isolated cardiac mitochondria. We conclude that chronic iron overload leads to cumulative iron-mediated damage to mtDNA and impaired synthesis of mitochondrial respiratory chain subunits. The resulting respiratory dysfunction may explain the slow development of cardiomyopathy in chronic iron overload and similar accumulation of damage to mtDNA may also explain the mitochondrial dysfunction observed in slowly progressing diseases such as neurodegenerative disorders.
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| 48. |
- Gao, Yan, et al.
(författare)
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Perovskite Hydroxide CoSn(OH)(6) Nanocubes for Efficient Photoreduction of CO2 to CO
- 2018
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Ingår i: ACS Sustainable Chemistry and Engineering. - : AMER CHEMICAL SOC. - 2168-0485. ; 6:1, s. 781-786
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite hydroxide CoSn(OH)(6) nanoparticles were synthesized and used for the first time in the photocatalytic reduction of CO2 to CO. Under mild reaction conditions and using [Ru(bpy)(3)](PF6)(2) as the photosensitizer, a high photocatalytic efficiency of 19.3 mu mol for CO evolution with a high selectivity of 86.46% was obtained. The photocatalytic TEOA activity and CO selectivity were further improved by adding weak Bronsted acids, as proton sources, to the system.
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| 49. |
- Gao, Yang, et al.
(författare)
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The Influence of Increased CO2 Concentrations on AMOC Interdecadal Variability Under the LGM Background
- 2024
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. - 2169-897X .- 2169-8996. ; 129:3
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the impact of rising CO2 levels on the Atlantic meridional overturning circulation's (AMOC) interdecadal variability within the context of the Last Glacial Maximum (LGM) background climate. Under heightened CO2 concentrations, the AMOC interdecadal variability intensifies dramatically, which is very different from the future warming case that shows a weakening of AMOC interdecadal variability in response to increased CO2 concentration. This unexpected phenomenon primarily results from the extensive retreat of sea ice, which exposes a larger portion of the ocean surface to efficiently feel the heat flux fluctuations from atmospheric processes. These findings underscore the significance of background climate conditions in shaping AMOC responses to increased CO2 and emphasize the necessity of considering these nuances to develop a more accurate understanding of AMOC dynamics in an evolving climate. Plain Language Summary The Atlantic meridional overturning circulation (AMOC) is an important component of the Earth system, and its interdecadal variability is predicted to be significantly weakened under future warming scenarios. In this paper, we analyze the response of AMOC interdecadal variability to rising CO2 levels under the background of the Last Glacial Maximum (LGM) and find that the AMOC interdecadal variability is intensified under increased CO2 , which is totally different from its response at the background of modern climate. Analyses suggest that this unexpected result is mainly caused by dramatic sea ice retreat, which exposes much seawater to efficiently receive large fluctuations of heat flux from atmospheric forcing. The findings reveal that the response of AMOC to increased CO2 and relevant dominant mechanism differs significantly under different climate conditions.
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| 50. |
- Gao, Zihao Rei, et al.
(författare)
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HPM-14 : A New Germanosilicate Zeolite with Interconnected Extra-Large Pores Plus Odd-Membered and Small Pores
- 2021
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:7, s. 3438-3442
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Tidskriftsartikel (refereegranskat)abstract
- HPM-14 is a new extra-large pore zeolite synthesized using imidazolium-based organic structure-directing agents (SDAs), fluoride anions, and germanium and silicon as tetrahedral components of the framework. Owing to the presence of stacking disorder, the structure elucidation of HPM-14 was challenging, and different techniques were necessary to clarify the details of the structure and to understand the nature of the disorder. The structure has been solved by three-dimensional electron-diffraction technique (3D ED) and consists of an intergrowth of two polymorphs possessing a three-dimensional channel system, including an extra-large pore opened through windows made up of sixteen tetrahedral atoms (16-membered ring, 16MR) as well as two additional sets of odd-membered (9MR) and small (8MR) pores. The intergrowth has been studied by scanning transmission electron microscopy (C-s-STEM) and powder X-ray diffraction simulations (DIFFaX), which show a large predominance of the monoclinic polymorph A.
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