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2025
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Abstract
Transient heat flux up to thousands of MW/m2 in a short pulse (~ms) in tokamak poses great challenge on plasma facing components (PFCs), a major concern for ITER. Despite numerous high heat flux tests, the analysis of in situ transient heat flux-induced damage on PFCs remains necessary. Such damages, including the melting and cracking of tungsten (W) PFCs, are notably observed on the divertor (dome and baffle plates) and limiter in EAST. These damages are identified as being induced by runaway electron loss during plasma disruption in the early startup phase of each plasma campaign. They typically occur at the leading edges or protruding parts of PFCs, sometimes accompanied by visible macrocracks. Regarding melting phenomena, three distinct grain layers are observed from the molten surface to the deeper regions: columnar grain, equiaxed grain (recrystallization region) and original grain. This grain distribution indicates a steep temperature gradient from the surface to the deeper regions during melting events, a characteristic feature for W under fusion-relevant transient heat flux loading from electron/ion beam tests. The surface morphologies of all melted PFCs are generally similar, characterized by undulated melting waves. The movement of the melting layer is primarily along the toroidal direction, as shown in the in-situ melting PFCs. The influence of the J×B force might not be significant due to the limited life of the melting pool, which results in limited acceleration time and expected bulk melt displacements, even if the J×B force is the dominant force. The directions of plasma pressure and Marangoni flow, both along the toroidal direction, might be the dominant forces here. Additionally, cracks at leading edges were observed on the divertor dome and baffle plates during post-mortem inspection. In some cases, dense cracks were visible in the melting region and even in areas far from the melting zone. It should be noted that cracks were only found on partially melted PFCs, which could be related to the base temperature when PFCs were hit by the runaway electron-induced transient heat flux. Furthermore, some columnar grains were observed to exfoliate from the material, indicating severe cracking. Since EAST has similar W PFCs to ITER, the transient heat flux-induced melting and cracking damages on W PFCs by runaway electrons during plasma disruption in EAST provide important references for ITER.- Book : ()
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2025
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2025
Structural virology has emerged as the foundation for the development of effective antiviral therapeutics. It is pivotal in providing crucial insights into the three-dimensional frame of viruses and viral proteins at atomic-level or near-atomic-level resolution. Structure-based assessment of viral components, including capsids, envelope proteins, replication machinery, and host interaction interfaces, is instrumental in unraveling the multiplex mechanisms of viral infection, replication, and pathogenesis. The structural elucidation of viral enzymes, including proteases, polymerases, and integrases, has been essential in combating viruses like HIV-1 and HIV-2, SARS-CoV-2, and influenza. Techniques including X-ray crystallography, Nuclear Magnetic Resonance spectroscopy, Cryo-electron Microscopy, and Cryo-electron Tomography have revolutionized the field of virology and significantly aided in the discovery of antiviral therapeutics. The ubiquity of chronic viral infections, along with the emergence and reemergence of new viral threats necessitate the development of novel antiviral strategies and agents, while the extensive structural diversity of viruses and their high mutation rates further underscore the critical need for structural analysis of viral proteins to aid antiviral development. This review highlights the significance of structure-based investigations for bridging the gap between structure and function, thus facilitating the development of effective antiviral therapeutics, vaccines, and antibodies for tackling emerging viral threats.- Book : 17(3)
- Pub. Date : 2025
- Page : pp.417-417
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2025
Background: Hodgkin lymphoma (HL) is a B-cell-derived malignancy and one of the most frequent types of lymphoma. The tumour cells typically exhibit multiple genomic alterations together with aberrantly activated signalling pathways, driven by paracrine and/or autocrine modes. SPP1 (alias osteopontin) is a cytokine acting as a signalling activator and has been connected with relapse in HL patients. To understand its pathogenic role, here, we investigated the mechanisms and function of deregulated SPP1 in HL. Methods: We screened public patient datasets and cell lines for aberrant SPP1 expression. HL cell lines were stimulated with SPP1 and subjected to siRNA-mediated knockdown. Gene and protein activities were analyzed by RQ-PCR, ELISA, Western blot, and immuno-cytology. Results: SPP1 expression was detected in 8.3% of classic HL patients and in HL cell line SUP-HD1, chosen to serve as an experimental model. The gene encoding SPP1 is located at chromosomal position 4q22 and is genomically amplified in SUP-HD1. Transcription factor binding site analysis revealed TALE and HOX factors as potential regulators. Consistent with this finding, we showed that aberrantly expressed PBX1 and HOXB9 mediate the transcriptional activation of SPP1. RNA-seq data and knockdown experiments indicated that SPP1 signals via integrin ITGB1 in SUP-HD1. Accordingly, SPP1 activated NFkB in addition to MAPK/ERK which in turn mediated the nuclear import of ETS2, activating oncogenic JUNB expression. Conclusions: SPP1 is aberrantly activated in HL cell line SUP-HD1 via genomic copy number gain and by homeodomain transcription factors PBX1 and HOXB9. SPP1-activated NFkB and MAPK merit further investigation as potential therapeutic targets in affected HL patients.- Book : 13(3)
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AbstractPurposeThe response of various detectors in small fields from a variety of treatment machines has been studied and is summarized in IAEA TRS‐483. However, data for the novel RefleXion system remains largely unexplored. This study measured the output correction factors of multiple detectors in small fields for a clinical RefleXion unit.MethodsThe RefleXion machine consists of a binary multi‐leaf collimator and two pairs of Y‐jaws with clinical openings of 1 and 2 cm. The reference dosimetry is applied to the 10 × 2 cm2 clinical‐reference field, and the output factors of different fields are presented relative to the clinical‐reference field. The responses of detectors Edge, Razor, Micro‐Diamond, A14SL, CC01 and CC03 in rectangular fields from 1.25 × 1 to 20 × 2 cm2 on the RefleXion unit was studied at a depth of 10 cm in an IBA Blue‐Phantom‐Helix with a 85 cm source‐to‐surface distance. Gafchromic EBT4 film data in a solid‐water phantom were used as the reference to obtain correction factors for the detectors.ResultsIn the fields of the 2 cm jaw, all 6 detectors showed similar responses to the film reference within around 0.5% except at the first field width (1.25 cm), where the Edge and Micro‐Diamond exhibited over‐response and the CC13 showed the volume effect of ion chambers. In the fields of the 1 cm jaw, the Edge and Micro‐Diamond had responses close to the film and the same over‐response at small field‐widths. Significant deviations of the CC13 (∼4%) and the A14SL (∼2.5%) from the film were present over the whole range of field widths.ConclusionsThe small field output correction factors of 6 kinds of detectors were determined for a RefleXion system, conforming to the formalism in TRS‐483. All detectors except CC13 fulfil the 5% correction limit recommended by the TRS‐483 for output factor measurement.- Book : ()
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2025
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