ORCID Profile
0000-0002-9051-1060
Current Organisation
University of Oxford
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Publisher: American Geophysical Union (AGU)
Date: 2021
DOI: 10.1029/2020GC009467
Abstract: The locations of ultralow‐velocity zones (ULVZs) at the core‐mantle boundary (CMB) have been linked to a variety of features including hot spot volcanoes and large low‐velocity province (LLVP) boundaries, yet only a small portion of the CMB region has been probed for ULVZ existence. Here we present a new map of lower mantle heterogeneity locations using a global collection of highly anomalous SPdKS recordings based on a dataset of more than 58,000 radial component seismograms, which s le 56.9% of the CMB by surface area. The inference of heterogeneity location using the SPdKS seismic phase is challenging due to source‐versus receiver‐side ambiguity. Due to this ambiguity, we conducted an inversion using the principle of parsimony. The inversion is conducted using a genetic algorithm which is repeated several thousand times in order to construct heterogeneity probability maps. This analysis reveals that at probabilities 0.5, 0.25, and 0.125 up to 1.3%, 8.2%, or 19.7% of the CMB may contain ULVZ‐like heterogeneities. These heterogeneities exist in all lower mantle settings, including both high‐ and low‐velocity regions. Additionally, we present evidence that the Samoan ULVZ may be twice as large as previously estimated, and also present evidence for the existence of additional mega‐sized ULVZs, such as a newly discovered ULVZ located to the east of the Philippines. We provide new evidence for the ULVZ east of the Philippines through an analysis of ScP records.
Publisher: MDPI AG
Date: 26-02-2020
DOI: 10.3390/MIN10030211
Abstract: Ultralow-velocity zones (ULVZs) at the core–mantle boundary (CMB) represent some of the most preternatural features in Earth’s mantle. These zones most likely contain partial melt, extremely high iron content ferropericlase, or combinations of both. We analyzed a new collection of 58,155 carefully processed and quality-controlled broadband recordings of the seismic phase SPdKS in the epicentral distance range from 106° to 115°. These data s le 56.9% of the CMB by surface area. From these recordings we searched for the most anomalous seismic waveforms that are indicative of ULVZ presence. We used a Bayesian approach to identify the regions of the CMB that have the highest probability of containing ULVZs, thereby identifying sixteen regions of interest. Of these regions, we corroborate well-known ULVZ existence beneath the South China Sea, southwest Pacific, the Samoa hotspot, the southwestern US/northern Mexico, and Iceland. We find good evidence for new ULVZs beneath North Africa, East Asia, and north of Papua New Guinea. We provide further evidence for ULVZs in regions where some evidence has been hinted at before beneath the Philippine Sea, the Pacific Northwest, and the Amazon Basin. Additional evidence is shown for potential ULVZs at the base of the Caroline, San Felix and Galapagos hotspots.
Publisher: Wiley
Date: 23-04-2021
Abstract: Compared to other tumors, glioblastoma (GBM) is extremely difficult to treat. Recently, photothermal therapy (PTT) has demonstrated advanced therapeutic efficacy however, because of the relatively low tissue‐penetration efficiency of laser light, its application in deep‐seated tumors remains challenging. Herein, bradykinin (BK) aggregation‐induced‐emission nanoparticles (BK@AIE NPs) are synthesized these offer selective penetration through the blood–tumor barrier (BTB) and strong absorbance in the near‐infrared region (NIR). The BK ligand can prompt BTB adenosine receptor activation, which enhances transportation and accumulation inside tumors, as confirmed by T 1 ‐weighted magnetic resonance and fluorescence imaging. The BK@AIE NPs exhibit high photothermal conversion efficiency under 980 nm NIR laser irradiation, facilitating the treatment of deep‐seated tumors. Tumor progression can be effectively inhibited to extend the survival span of mice after spatiotemporal PTT. NIR irradiation can eradicate tumor tissues and release tumor‐associated antigens. It is observed that the PTT treatment of GBM‐bearing mice activates natural killer cells, CD3 + T cells, CD8 + T cells, and M1 macrophages in the GBM area, increasing the therapeutic efficacy. This study demonstrates that NIR‐assisted BK@AIE NPs represent a promising strategy for the improved systematic elimination of GBMs and the activation of local brain immune privilege.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
No related grants have been discovered for Tarje Nissen-Meyer.