185 research outputs found

    Giant perivascular spaces: two case reports

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    Giant perivascular spaces or Virchow-Robin spaces (VRSs) are uniquely inherent developmental malformation and are generally lined by ependymal or leptomeningeal cells. The cerebral hemispheres with VRSs present multiple cysts of curvilinear, round, oval, or layered configuration, which have the same signal intensity as the cerebrospinal fluid (CSF) and represent extremely dilated VRSs. The cortex became extremely thin with a well-defined margin. Herein, we report two cases of true giant perivascular spaces and present a review of pertinent literature. A patient has multiple cysts in the unilateral and bilateral and has polycystic liver. The clinical presentation, image logical features, and diagnosis are discussed

    RIS-assisted Scheduling for High-Speed Railway Secure Communications

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    With the rapid development of high-speed railway systems and railway wireless communication, the application of ultra-wideband millimeter wave band is an inevitable trend. However, the millimeter wave channel has large propagation loss and is easy to be blocked. Moreover, there are many problems such as eavesdropping between the base station (BS) and the train. As an emerging technology, reconfigurable intelligent surface (RIS) can achieve the effect of passive beamforming by controlling the propagation of the incident electromagnetic wave in the desired direction.We propose a RIS-assisted scheduling scheme for scheduling interrupted transmission and improving quality of service (QoS).In the propsed scheme, an RIS is deployed between the BS and multiple mobile relays (MRs). By jointly optimizing the beamforming vector and the discrete phase shift of the RIS, the constructive interference between direct link signals and indirect link signals can be achieved, and the channel capacity of eavesdroppers is guaranteed to be within a controllable range. Finally, the purpose of maximizing the number of successfully scheduled tasks and satisfying their QoS requirements can be practically realized. Extensive simulations demonstrate that the proposed scheme has superior performance regarding the number of completed tasks and the system secrecy capacity over four baseline schemes in literature.Comment: 15 pages, 10 figures, to appear in IEEE Transactions on Vehicular Technolog

    Potential therapeutic strategy for non-Hodgkin lymphoma by anti-CD20scFvFc/CD28/CD3zeta gene tranfected T cells

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    <p>Abstract</p> <p>Background</p> <p>Anti-CD20 monoclonal antibody treatment has not only increased survival and cure rates in many non-Hodgkin lymphomas, but also has prompted an explosion in the development of novel antibodies and biologically active substances with specific cellular targets in the field of malignancies treatment. Since the robust immune responses are elicited by the gene-modified T cells, gene based T cell therapy may also provide a powerful tool for cancer immunotherapy.</p> <p>Methods</p> <p>In this study, we developed a vector construction encoding a chimeric T cell receptor that recognizes the CD20 antigen and delivers co-stimulatory signals to achieve T cell activation. One non-Hodgkin lymphoma cell line Raji cells co-cultured with peripheral blood-derived T cells were stably transfected with anti-CD20scFvFc/CD28/CD3zeta gene or anti-CD20scFvFc gene. T cells expressing anti-CD20scFvFc/CD28/CD3zeta or anti-CD20scFvFc gene co-cultured with CD20 positive Raji cells for different times. Cell lysis assay was carried by [<sup>3</sup>H]TdR release assay. The expressions of Fas, Bcl-2 and Caspase-3 of Raji cells were detected by flow cytometric. The secretion of IFN-gamma and IL-2 in co-culture medium was tested by ELISA assay. Activity of AP-1 was analyzed by EMSA.</p> <p>Results</p> <p>Following efficient transduction of peripheral blood-derived T cells with anti-CD20scFvFc/CD28/CD3zeta gene, an obvious cell lysis of Raji cells was observed in co-culture. T cells transduced anti-CD20scFvFc/CD28/CD3zeta gene had superior secretion of IFN-gamma and IL-2 compared to T cells transduced anti-CD20scFvFc gene. Also it led to a much stronger Fas-induced apoptosis signaling transduction in target cancer cells.</p> <p>Conclusion</p> <p>So adoptively T cells transduced anti-CD20scFvFc/CD28/CD3zeta gene mediates enhanced anti-tumor activities against CD20 positive tumor cells, suggesting a potential of gene-based immunotherapy for non-Hodgkin lymphoma.</p

    Study on evolution law of mechanical properties of coal samples subjected to freezing and freeze-thaw cycles of liquid nitrogen

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    The permeability of coal reservoir is generally low in China, how to effectively improve the permeability of coal reservoir is a key and difficult point of coalbed methane exploitation, Liquid nitrogen fracturing technology as a kind waterless fracturing technology has received extensive attention in recent years. In order to reveal the influence of liquid nitrogen freezing and freeze-thaw on the mechanical properties of coal, the temperature distribution of coal samples was monitored by infrared thermal imaging technology, and uniaxial compression and acoustic emission tests were performed on the coal samples after the liquid nitrogen freezing and freezethaw, the P-wave velocity, porosity, acoustic emission and energy evolution characteristics of coal samples before and after the freezing and freeze thaw were analyzed. The research result showed that: ①After 360 min freezing and 12 freeze-thaw cycles, the P-wave velocity of coal samples decreased by 58.2% and 64.7%, respectively. The P-wave velocity does not decrease significantly during the initial freezing and freeze-thaw cycle stages, the velocity gradually decreases with the increase of freezing time and freeze-thaw cycles. ②The temperature of the coal sample gradually decreases with increase of freezing times. The surface temperature of the coal sample drops below -60°C after the liquid nitrogen frozen for 180s, the temperature distribution fluctuations at the center of the coal sample occurs due to the different thermal conduction coefficient of the coal particles. ③After liquid nitrogen freezing and freezethaw, the elastic modulus of coal sample decreases exponentially, while the porosity gradually increases. The increase in porosity of the coal sample after liquid nitrogen freeze-thaw is greater than that after liquid nitrogen freezing. ④The acoustic emission activity of coal samples during uniaxial loading is divided into development phase, active phase and severe phase, the maximum acoustic emission ringing count and cumulative acoustic emission ringing count of coal samples increase with the increase of freezing time and freeze-thaw cycles. ⑤Liquid nitrogen freezing and freeze-thaw will weaken the energy storage limit of coal sample, resulting in the reduction of the total energy, elastic energy and dissipated energy at the peak point during the uniaxial loading process

    Autophagic Degradation Deficit Involved in Sevoflurane-Induced Amyloid Pathology and Spatial Learning Impairment in APP/PS1 Transgenic Mice

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    The adverse effects of anesthetics on elderly people, especially those with brain diseases are very concerning. Whether inhaled anesthetics have adverse effects on Alzheimer’s disease (AD), which is the most common form of dementia with brain degenerative changes, remains controversial. Autophagy, a crucial biological degradation process, is extremely important for the pathogenesis of AD. In this study, the inhaled anesthetic sevoflurane elicited many enlarged autolysosomes and impaired the overall autophagic degradation in the hippocampus of an AD mouse model, which is involved in the accumulation of amyloid-β (Aβ) and spatial learning deficits. However, rapamycin treatment counteracted all these effects. The results suggested that inhaled anesthetics may accelerate the pathological process of AD, and enlarged autolysosomes may be a new marker for prediction and diagnosis of the neurotoxicity of anesthetics in AD

    TFEB Probably Involved in Midazolam-Disturbed Lysosomal Homeostasis and Its Induced β-Amyloid Accumulation

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    Alzheimer’s disease (AD) is one of the most common neurodegenerative diseases, and β-amyloid (Aβ) plays a leading role in the pathogenesis of AD. The transcription factor EB (TFEB), a main regulating factor of autophagy and lysosome biosynthesis, is involved in the pathogenesis of AD by regulating autophagy-lysosomal pathways. To date, the choice of anesthetics during surgery in patients with neurodegenerative diseases and evaluation of the effects and underlying mechanisms in these patients have rarely been reported. In this study, the HEK293-APP cells overexpressing APP and Hela cells were used. The cells were treated with midazolam at different concentrations and at different times, then lysosomes were stained by lysotracker and their morphology was observed under a fluorescence microscope. The number and size of lysosomes were analyzed using the ImageJ software. The levels of TFEB in the nucleus and APP-cleaved intracellular proteins were detected by nuclear separation and Western Blot. Finally, ELISA was used to detect the levels of Aβ40 and Aβ42 in the cells after drug treatment. We found that 30 μM midazolam decreased the number of lysosomes and increased its size in HEK293 and HeLa cells. However, 15 μM midazolam transiently disturbed lysosomal homeostasis at 24 h and recovered it at 36 h. Notably, there was no significant difference in the extent to which lysosomal homeostasis was disturbed between treatments of different concentrations of midazolam at 24 h. In addition, 30 μM midazolam prevents the transport of TFEB to the nucleus in either normal or starved cells. Finally, the intracellular C-terminal fragment β (CTFβ), CTFα, Aβ40 and Aβ42 levels were all significantly elevated in 30 μM midazolam-treated HKE293-APP cells. Collectively, the inhibition of TFEB transport to the nucleus may be involved in midazolam-disturbed lysosomal homeostasis and its induced Aβ accumulation in vitro. The results indicated the risk of accelerating the pathogenesis of AD by midazolam and suggested that TFEB might be a candidate target for reduction of midazolam-dependent neurotoxicity

    Greenhouse gas emissions from U.S. crude oil pipeline accidents:1968 to 2020

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    Abstract Crude oil pipelines are considered as the lifelines of energy industry. However, accidents of the pipelines can lead to severe public health and environmental concerns, in which greenhouse gas (GHG) emissions, primarily methane, are frequently overlooked. While previous studies examined fugitive emissions in normal operation of crude oil pipelines, emissions resulting from accidents were typically managed separately and were therefore not included in the emission account of oil systems. To bridge this knowledge gap, we employed a bottom-up approach to conducted the first-ever inventory of GHG emissions resulting from crude oil pipeline accidents in the United States at the state level from 1968 to 2020, and leveraged Monte Carlo simulation to estimate the associated uncertainties. Our results reveal that GHG emissions from accidents in gathering pipelines (~720,000 tCO2e) exceed those from transmission pipelines (~290,000 tCO2e), although significantly more accidents have occurred in transmission pipelines (6883 cases) than gathering pipelines (773 cases). Texas accounted for over 40% of total accident-related GHG emissions nationwide. Our study contributes to enhanced accuracy of the GHG account associated with crude oil transport and implementing the data-driven climate mitigation strategies

    Electron pairing in the pseudogap state revealed by shot noise in copper oxide junctions

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    In the quest to understand high-temperature superconductivity in copper oxides, debate has been focused on the pseudogap—a partial energy gap that opens over portions of the Fermi surface in the ‘normal’ state above the bulk critical temperature. The pseudogap has been attributed to precursor superconductivity, to the existence of preformed pairs and to competing orders such as charge-density waves. A direct determination of the charge of carriers as a function of temperature and bias could help resolve among these alternatives. Here we report measurements of the shot noise of tunnelling current in high-quality La_(2−x)Sr)xCuO)4/La)2CuO)4/La_(2−x)Sr)xCuO)4 (LSCO/LCO/LSCO) heterostructures fabricated using atomic layer-by-layer molecular beam epitaxy at several doping levels. The data delineate three distinct regions in the bias voltage–temperature space. Well outside the superconducting gap region, the shot noise agrees quantitatively with independent tunnelling of individual charge carriers. Deep within the superconducting gap, shot noise is greatly enhanced, reminiscent of multiple Andreev reflections. Above the critical temperature and extending to biases much larger than the superconducting gap, there is a broad region in which the noise substantially exceeds theoretical expectations for single-charge tunnelling, indicating pairing of charge carriers. These pairs are detectable deep into the pseudogap region of temperature and bias. The presence of these pairs constrains current models of the pseudogap and broken symmetry states, while phase fluctuations limit the domain of superconductivity

    The role of CD8+ T cell clones in immune thrombocytopenia

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    Immune thrombocytopenia (ITP) is traditionally considered an antibody-mediated disease. However, a number of features suggest alternative mechanisms of platelet destruction. In this study, we use a multi-dimensional approach to explore the role of cytotoxic CD8+ T cells in ITP. We characterised patients with ITP and compared them to age-matched controls using immunophenotyping, next-generation sequencing of T cell receptor (TCR) genes, single-cell RNA sequencing, and functional T cell and platelet assays. We found that adults with chronic ITP have increased polyfunctional, terminally differentiated effector memory CD8+ T cells (CD45RA+CD62L-) expressing intracellular interferon-g, tumour necrosis factor-a, and Granzyme B defining them as TEMRA cells. These TEMRA cells expand when the platelet count falls and show no evidence of physiological exhaustion. Deep sequencing of the T cell receptor showed expanded T cell clones in patients with ITP. T cell clones persisted over many years, were more prominent in patients with refractory disease, and expanded when the platelet count was low. Combined single-cell RNA and TCR sequencing of CD8+ T cells confirmed that the expanded clones are TEMRA cells. Using in vitro model systems, we show that CD8+ T cells from patients with ITP form aggregates with autologous platelets, release interferon-g and trigger platelet activation and apoptosis through TCR-mediated release of cytotoxic granules. These findings of clonally expanded CD8+ T cells causing platelet activation and apoptosis provide an antibody-independent mechanism of platelet destruction, indicating that targeting specific T-cell clones could be a novel therapeutic approach for patients with refractory ITP
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