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  • 2025


    • Book : 210()
    • Pub. Date : 2025
    • Page : pp.110860
    • Keyword :
  • 2025


    • Book : 210()
    • Pub. Date : 2025
    • Page : pp.110837
    • Keyword :
  • 2025

    JOURNAL/nrgr/04.03/01300535-202505000-00025/figure1/v/2024-07-28T173839Z/r/image-tiff

    Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair. We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling, influencing their activation such that they can promote neurological recovery. However, the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear. In this study, we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-α expression but suppressed insulin-like growth factor-1 expression. However, recombinant complement receptor 2-conjugated Crry (CR2-Crry) reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia, CXCL12, and tumor necrosis factor-α. Additionally, we observed that, in response to stimulation (including stimulation by CXCL12 secreted by activated microglia), CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4, Crry, and Akt signaling to modulate microglial activation. In agreement with these in vitro experimental results, we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation, leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice. Notably, these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury, cerebral edema, and neurological disorders post-closed head injury. In conclusion, our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry, thereby promoting induced neural stem cell-mediated improvement of neuronal injury, cerebral edema, and neurological disorders following closed head injury.


    • Book : 20(5)
    • Pub. Date : 2025
    • Page : pp.1416-1430
    • Keyword :
  • 2025


    • Book : 352()
    • Pub. Date : 2025
    • Page : pp.128140
    • Keyword :
  • 2025


    • Book : 150()
    • Pub. Date : 2025
    • Page : pp.632-644
    • Keyword :
  • 2025


    • Book : 12(suppl1)
    • Pub. Date : 2025
    • Page :
    • Keyword :
  • 2025

    Abstract

    Aging degradation is the main form of failure of rubber in service, leading to a decline in its physical and mechanical properties. This paper presents an efficient method for assessing the aging degradation of rubber using the quasi-static component (QSC) of ultrasonic longitudinal waves induced by acoustic radiation. The experiments quantitatively observe the response of the QSC pulse to different levels of aging degradation. A pulse-echo ultrasonic transducer is employed to simultaneously capture the primary longitudinal wave (PLW) and QSC echoes, enabling the determination of the acoustic nonlinearity parameter of QSC with a single transducer excitation. The results suggest that, in comparison to traditional linear ultrasonic techniques based on attenuation coefficient and wave velocity measurements, the relative acoustic nonlinear parameter of QSC proves to be more sensitive to aging degradation in rubber. Particularly, the amplitude of the QSC pulse undergoes a significant change with increasing aging degradation, even when the PLW tone burst is completely attenuated. These findings confirm the effectiveness of QSC as a method for evaluating aging degradation in highly attenuative materials.


    • Book : 8(2)
    • Pub. Date : 2025
    • Page : pp.021007
    • Keyword :
  • 2025

    Abstract

    This paper presents the findings of studies conducted at Canadian Nuclear Laboratories (CNL) to support the development of small modular reactor (SMR) designs. The primary focus of this research was to evaluate the suitability of the zero energy deuterium 2 (ZED-2) critical facility in replicating the reactor physics environment for a pressurized water reactor small modular reactor (PWR-SMR) design concept through similarity and nuclear data sensitivity studies, using the TSUNAMI code suite. It was found that previous ZED-2 experiments would be quite promising for application to a PWR-SMR design. Further similarity and sensitivity studies of hypothetical mixed-lattice substitution experiments, where PWR-SMR fuel assemblies were placed into a substitution region of the ZED-2 critical facility demonstrated improved similarity. Subsequent analyses focused on the impacts of dissolved Gadolinium (Gd) and boron (B) neutron absorbers, suggesting the feasibility of using future ZED-2 experiments to more closely replicate PWR-SMR reactor physics behavior. Building on these initial findings, the design for PWR-SMR fuel assembly substitution experiments in the ZED-2 facility were explored further. These hypothetical experiments feature water-cooled PWR-type fuel assemblies inside a shroud, surrounded by heavy-water-moderated CANdu FLEXible, Low Enriched Uranium, Recovered Uranium (CANFLEX-LEU/CANFLEX-RU) fuel channels. Similarity and sensitivity studies indicate a very high level of similarity of these experiments for PWR-SMR design applications.


    • Book : 11(2)
    • Pub. Date : 2025
    • Page : pp.021501
    • Keyword :
  • 2025

    Abstract

    In this study, heat fluxes qc for condensation from steam and air mixtures on vertical flat plates were evaluated by using existing experimental data and qc correlations, in order to provide one of boundary conditions for computational fluid dynamics (CFD) analysis in a primary containment vessel (PCV) of nuclear power plants during accident conditions. Existing qc,fc correlations for forced convection condensation overestimated or underestimated experimental data qc,exp measured with the CONAN facility, and a combination of the selected existing qc,fc correlation and the suction correction factor θC was proposed to obtain good agreement between the qc,cal values computed with the combination and the qc,exp values. For natural convection condensation, it was found that the qc,nc values were largely different between those measured in closed vessels with evaporation and condensation and in flow channels with decreasing the mixture velocity, and hence, the present evaluation focused on qc,nc obtained in the flow channels. It was also found that uncertainty became large when the qc,nc values were computed by changing the Sherwood number Shfc in the qc,fc correlation to Shnc for natural convection. The qc,exp values measured with the COPAIN facility were well expressed by the qc,nc correlation proposed by Corradini (1984, “Turbulent Condensation on a Cold Wall in the Presence of a Noncondensable Gas,” Nucl. Technol., 64(2), pp. 186-195), but the published data were few. Therefore, collection of experimental or numerical qc,nc values is necessary in the future.


    • Book : 11(2)
    • Pub. Date : 2025
    • Page : pp.021401
    • Keyword :
  • 2025

    Hybrid Ultraviolet photodetector (UVPD) was fabricated by depositing reduced graphene oxide on zinc oxide nanorods (ZnO NRs) array-coated FTO glass. Structural and optical properties of ZnO NRs were studied using TEM, SEM, XRD and UV-Vis spectroscopy. Graphene oxide (GO) sheets were synthesized from graphite powder using the modified Hummer’s method. rGO films were obtained after illuminating the GO in UV radiation. The formation of rGO and GO films was studied using AFM surface topography and UV-Vis spectroscopy. External quantum efficiency (EQE), responsivity and transient response of rGO/ZnO NR-based UV photodetector were studied in detail. The photodetector device shows very high EQE ($ \sim $45 257%) and responsivity ($ R$$ \sim $130 A/W).


    • Book : 15(3)
    • Pub. Date : 2025
    • Page : pp.2450019
    • Keyword :