| 11. |
- Lu, R.S., et al.
(författare)
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A ring-like accretion structure in M87 connecting its black hole and jet
- 2023
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 616:7958, s. 686-690
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Tidskriftsartikel (refereegranskat)abstract
- The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.
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| 12. |
- Luo, Jun, et al.
(författare)
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Effects of carbon pre-silicidation implant into Si substrate on NiSi
- 2014
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 120, s. 178-181
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the effects of carbon pre-silicidation implant into Si(1 0 0) substrate on NiSi were investigated. NiSi films with carbon pre-silicidation implant to different doses were characterized by means of sheet resistance measurements, X-ray diffraction, scanning electron microscopy (SEM), planar view transmission electron microscopy (TEM) and second ion mass spectroscopy (SIMS). The presence of C is found to indeed significantly improve the thermal stability of NiSi as well as tends to change the preferred orientations of polycrystalline NiSi. The homogeneously distributed C at NiSi grain boundaries and C peak at NiSi/Si interface is ascribed to the improved thermal stability of NiSi. More importantly, the dose of carbon pre-silicidation implant also plays a key role in the formation of NiSi, which is suggested not to exceed a critical value about 5 x 10(15) cm(-2) in practical application in accordance with the results achieved in this work. (C) 2013 Elsevier B.V. All rights reserved.
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| 13. |
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| 14. |
- Luo, Jun, et al.
(författare)
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Thermal Stability and Dopant Segregation for Schottky Diodes With Ultrathin Epitaxial NiSi(2-y)
- 2011
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 32:8, s. 1029-1031
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Tidskriftsartikel (refereegranskat)abstract
- The Schottky barrier height (SBH) of an ultrathin epitaxial NiSi(2-y) film grown on Si(100) is modified significantly by means of dopant segregation (DS). The DS process begins with the NiSi(2-y) formation and is followed by dopant implantation and drive-in annealing. The rapid lattice restoration and superior morphological stability upon heat treatment up to 800 degrees C allow the epitaxial NiSi(2-y) film to take full advantage of the DS process. For drive-in annealing below 750 degrees C, the effective SBH is altered to similar to 0.9-1 eV for both electrons and holes by B-DS and As-DS, respectively, without deteriorating the integrity of the NiSi(2-y) film.
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| 15. |
- Luo, Jun, et al.
(författare)
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Variation of Schottky barrier height induced by dopant segregation monitored by contact resistivity measurements
- 2014
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 120, s. 174-177
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Tidskriftsartikel (refereegranskat)abstract
- Change of contact resistivity (rho(c)) is monitored for evaluation of Schottky barrier height (SBH) variation induced by dopant segregation (DS). This method is particularly advantageous for metal-semiconductor contacts of small SBH, as it neither requires low-temperature measurement needed in current-voltage characterization of Schottky diodes nor is affected by reverse leakage current often troubling capacitance-voltage characterization. With PtSi contact to both n- and p-type diffusion regions, and the use of opposite or alike dopants implant into pre-formed PtSi films followed by drive-in anneal at different temperatures to induce DS at PtSi/Si interface, the formation of interfacial dipole is confirmed as the responsible cause for modification of effective SBHs thus the increase or decrease of rho(c). A tentative explanation for the change of contact resistivity based on interfacial dipole theory is provided in this work. Influences and interplay of interfacial dipole and space charge on effective SBH are also discussed. (C) 2013 Elsevier B.V. All rights reserved.
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| 16. |
- Shi, Tian-Le, et al.
(författare)
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High-quality genome assembly enables prediction of allele-specific gene expression in hybrid poplar
- 2024
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Ingår i: Plant Physiology. - : Oxford University Press. - 0032-0889 .- 1532-2548. ; 195:1, s. 652-670
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Tidskriftsartikel (refereegranskat)abstract
- Poplar (Populus) is a well-established model system for tree genomics and molecular breeding, and hybrid poplar is widely used in forest plantations. However, distinguishing its diploid homologous chromosomes is difficult, complicating advanced functional studies on specific alleles. In this study, we applied a trio-binning design and PacBio high-fidelity long-read sequencing to obtain haplotype-phased telomere-to-telomere genome assemblies for the 2 parents of the well-studied F1 hybrid “84K” (Populus alba × Populus tremula var. glandulosa). Almost all chromosomes, including the telomeres and centromeres, were completely assembled for each haplotype subgenome apart from 2 small gaps on one chromosome. By incorporating information from these haplotype assemblies and extensive RNA-seq data, we analyzed gene expression patterns between the 2 subgenomes and alleles. Transcription bias at the subgenome level was not uncovered, but extensive-expression differences were detected between alleles. We developed machine-learning (ML) models to predict allele-specific expression (ASE) with high accuracy and identified underlying genome features most highly influencing ASE. One of our models with 15 predictor variables achieved 77% accuracy on the training set and 74% accuracy on the testing set. ML models identified gene body CHG methylation, sequence divergence, and transposon occupancy both upstream and downstream of alleles as important factors for ASE. Our haplotype-phased genome assemblies and ML strategy highlight an avenue for functional studies in Populus and provide additional tools for studying ASE and heterosis in hybrids.
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| 17. |
- Tian, Chao, et al.
(författare)
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Overexpression of connective tissue growth factor WISP-1 in Chinese primary rectal cancer patients
- 2007
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Ingår i: World Journal of Gastroenterology. - 1007-9327 .- 2219-2840. ; 13:28, s. 3878-3882
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To clarify the expression change of Wnt-induced secreted protein-1 (WISP-1) in human rectal cancer and to determine whether it is correlated with invasion and metastasis of human rectal cancer. Methods: Eighty-six paired samples of rectal cancer and surgically resected distant normal rectal tissue were collected and allocated into cancer group and control group respectively. WISP-1 mRNA was detected by relative quantitative real-time RT-PCR and WISP-1 protein was examined by immunohistochemical staining. Results: WISP-1 gene overexpression was found in 65% (56/86) primary rectal cancers, 2-30 times that of the level in normal matched rectal tissues (P = 0.001). The mRNA expression level was correlated with Duke's staging, histological differentiation grade and lymph node status. The WISP-1 protein expression was in accordance with mRNA expression level. The positive degree of immunohistochemical staining in the cancer group (1.40 ± 0.35) was different from that in control group (1.04 ± 0.08, P < 0.001). Moreover, in cancer group the positive staining degree in high-level mRNA cancers (1.46 ± 0.37, n = 56) was higher than that in low-level mRNA (1.28 ± 0.28, n = 30, P = 0.018). Conclusion: Aberrant levels of WISP-1 expression may play a role in rectal tumorigenesis. WISP-1 may be used as a specific clinical diagnosis and prognosis marker in rectal cancer. © 2007 WJG. All rights reserved.
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| 18. |
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| 19. |
- Jia, Kai-Hua, et al.
(författare)
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Chromosome-scale assembly and evolution of the tetraploid Salvia splendens (Lamiaceae) genome
- 2021
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Ingår i: Horticulture Research. - : Oxford University Press (OUP). - 2052-7276 .- 2662-6810. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Polyploidization plays a key role in plant evolution, but the forces driving the fate of homoeologs in polyploid genomes, i.e., paralogs resulting from a whole-genome duplication (WGD) event, remain to be elucidated. Here, we present a chromosome-scale genome assembly of tetraploid scarlet sage (Salvia splendens), one of the most diverse ornamental plants. We found evidence for three WGD events following an older WGD event shared by most eudicots (the γ event). A comprehensive, spatiotemporal, genome-wide analysis of homoeologs from the most recent WGD unveiled expression asymmetries, which could be associated with genomic rearrangements, transposable element proximity discrepancies, coding sequence variation, selection pressure, and transcription factor binding site differences. The observed differences between homoeologs may reflect the first step toward sub- and/or neofunctionalization. This assembly provides a powerful tool for understanding WGD and gene and genome evolution and is useful in developing functional genomics and genetic engineering strategies for scarlet sage and other Lamiaceae species.
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| 20. |
- Liu, Chaocheng, et al.
(författare)
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Probing the Néel-Type Antiferromagnetic Order and Coherent Magnon–Exciton Coupling in Van Der Waals VPS3
- 2023
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Ingår i: Advanced Materials. - 0935-9648. ; 35:30
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Tidskriftsartikel (refereegranskat)abstract
- 2D van der Waals (vdW) antiferromagnets have received intensive attention due to their terahertz resonance, multilevel magnetic-order states, and ultrafast spin dynamics. However, accurately identifying their magnetic configuration still remains a challenge owing to the lack of net magnetization and insensitivity to external fields. In this work, the Néel-type antiferromagnetic (AFM) order in 2D antiferromagnet VPS3 with the out-of-plane anisotropy, which is demonstrated by the temperature-dependent spin–phonon coupling and second-harmonic generation (SHG), is experimentally probed. This long-range AFM order even persists at the ultrathin limit. Furthermore, strong interlayer exciton–magnon coupling (EMC) upon the Néel-type AFM order is detected based on the monolayer WSe2/VPS3 heterostructure, which induces an enhanced excitonic state and further certifies the Néel-type AFM order of VPS3. The discovery provides optical routes as the novel platform to study 2D antiferromagnets and promotes their potential applications in magneto-optics and opto-spintronic devices.
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