191 research outputs found

    Surgical treatment of primary hepatic neuroendocrine tumor diagnosed by Al18F-NOTA-Octreotide PET/CT: a case report

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    Neuroendocrine tumors (NETs) are a heterogeneous group of tumors originating from peptide-producing neurons and neuroendocrine cells. The liver is the most common site of metastasis for NETs, while primary hepatic neuroendocrine tumors (PHNETs) are exceedingly rare. While somatostatin receptor scintigraphy (SRS) has demonstrated superior efficacy compared to [18F]FDG PET imaging in the diagnosis of neuroendocrine tumors, [18F]AlF-NOTA-Octreotide ([18F]AlF-OC) PET/CT also exhibits specific advantages over SRS. This article presents a case study of a patient with a liver mass who underwent sequential [18F]FDG and [18F]AlF-OC PET/CT scans, ruling out hepatocellular carcinoma and confirming the diagnosis of PHNETs. Subsequently, the patient underwent surgical treatment. From another perspective, [18F]AlF-OC exhibits distinct advantages. The postoperative pathology revealed a PHNETs, which further emphasizes its clinical rarity

    The interactions of volcanism and clastic sedimentation in rift basins: Insights from the Palaeogene-Neogene Shaleitian uplift and surrounding sub-basins, Bohai Bay Basin, China

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    Although volcanism is an important process in the evolution of rift basins, current tectono-sedimentary models largely neglect its impact on sediment supply, transport pathways, and depositional systems. In this paper, we integrate core, well logs, and 3D seismic data from the Palaeogene-Neogene Shaleitian (SLT) uplift and surrounding sub-basins, Bohai Bay Basin, China, to investigate the sedimentology and geomorphology of a volcanic rift basin. Results of this study show that the spatial distribution of extrusive centres was strongly controlled by basement-involved intra-basin normal faults. During the early part of the syn-rift stage, the SLT uplift supplied sediments to transverse fan deltas and braided-river deltas that fringed the adjacent syn-rift depocentres. Volcanic deposits mainly occurred as relatively thin lava flow and pyroclastic facies that partially filled fault-controlled topographic lows, reducing topographic rugosity, and enhanced breaching of basement highs between syn-rift depocentres. Integration of drainage to the syn-rift depocentres and development of through-flowing axial depositional systems was enhanced. During the later part of syn-rift and in early post-rift stages, the SLT uplift was progressively inundated, reducing sediment supply to the fringing transverse depositional systems. In contrast, axial braided-river deltas became the main depositional systems, sourced by large hinterland drainage from the Yanshan fold-belt to the northwest. Volcanism in the late syn-rift and early post-rift occurs as thick lava flow and pyroclastic facies that infill rift topographic lows and locally blocked axial fluvial systems creating isolated lakes. Within hanging wall depocentres, volcanic topographic highs split and diverted axial fluvial and deltaic systems. Furthermore, volcanism supplied large volumes of volcanic sediment to the rift resulting in increased sedimentation rates, and the development of unstable subaerial and subaqueous slopes and deposits, increasing the occurrence of landslides. Based on the observations of this study we update tectono-sedimentary models for rift basins to include volcanism.publishedVersio

    Semidiscrete optical vortex droplets in quasi-phase-matched photonic crystals

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    A new scheme for producing semidiscrete self-trapped vortices (\textquotedblleft swirling photon droplets\textquotedblright ) in photonic crystals with competing quadratic (χ(2)\chi ^{(2)}) and self-defocusing cubic (χ(3)\chi ^{(3)}) nonlinearities is proposed. The photonic crystal is designed with a striped structure, in the form of spatially periodic modulation of the χ(2)\chi ^{(2)} susceptibility, which is imposed by the quasi-phase-matching technique. Unlike previous realizations of semidiscrete optical modes in composite media, built as combinations of continuous and arrayed discrete waveguides, the semidiscrete vortex droplets are produced here in the fully continuous medium. This work reveals that the system supports two types of semidiscrete vortex droplets, \textit{viz}., onsite- and intersite-centered ones, which feature, respectively, odd and even numbers of stripes, N\mathcal{N}. Stability areas for the states with different values of N\mathcal{N} are identified in the system's parameter space. Some stability areas overlap with each others, giving rise to multistability of states with different N\mathcal{N}. The coexisting states are mutually degenerate, featuring equal values of the Hamiltonian and propagation constant. An experimental scheme to realize the droplets is outlined, suggesting new possibilities for the long-distance transmission of structured light carrying orbital angular momentum in nonlinear media.Comment: 9 pages, 7 figures, and 82 reference

    STPrivacy: Spatio-Temporal Privacy-Preserving Action Recognition

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    Existing methods of privacy-preserving action recognition (PPAR) mainly focus on frame-level (spatial) privacy removal through 2D CNNs. Unfortunately, they have two major drawbacks. First, they may compromise temporal dynamics in input videos, which are critical for accurate action recognition. Second, they are vulnerable to practical attacking scenarios where attackers probe for privacy from an entire video rather than individual frames. To address these issues, we propose a novel framework STPrivacy to perform video-level PPAR. For the first time, we introduce vision Transformers into PPAR by treating a video as a tubelet sequence, and accordingly design two complementary mechanisms, i.e., sparsification and anonymization, to remove privacy from a spatio-temporal perspective. In specific, our privacy sparsification mechanism applies adaptive token selection to abandon action-irrelevant tubelets. Then, our anonymization mechanism implicitly manipulates the remaining action-tubelets to erase privacy in the embedding space through adversarial learning. These mechanisms provide significant advantages in terms of privacy preservation for human eyes and action-privacy trade-off adjustment during deployment. We additionally contribute the first two large-scale PPAR benchmarks, VP-HMDB51 and VP-UCF101, to the community. Extensive evaluations on them, as well as two other tasks, validate the effectiveness and generalization capability of our framework

    Molecular cloning and in silico analysis of the duck (Anas platyrhynchos) MEF2A gene cDNA and its expression profile in muscle tissues during fetal development

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    The role of myogenic enhancer transcription factor 2a (MEF2A) in avian muscle during fetal development is unknown. In this work, we cloned the duck MEF2A cDNA sequence (GenBank accession no. HM460752) and examined its developmental expression profiles in cardiac muscle, non-vascular smooth muscle and skeletal muscle. Duck MEF2A cDNA comprised 1479 bp encoding 492 amino acid residues. In silico analysis showed that MEF2A contained MADS (MCM1, AGAMOUS, DEFICIENS and SRF - serum response factor), MEF2 and mitogen-activated protein kinase (MAPK) transcription domains with high homology to related proteins in other species. Modified sites in these domains were conserved among species and several variants were found. Quantitative PCR showed that MEF2A was expressed in all three muscles at each developmental stage examined, with the expression in smooth muscle being higher than in the other muscles. These results indicate that the conserved domains of duck MEF2A, including the MADS and MEF2 domains, are important for MEF2A transcription factor function. The expression of MEF2A in duck smooth muscle and cardiac muscle suggests that MEF2A plays a role in these two tissues
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