958 research outputs found

    Potential of Constraining Propagation Parameters of Galactic Cosmic Rays with the High Energy cosmic-Radiation Detection facility onboard China's Space Station

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    Precise measurements of the spectra of secondary and primary cosmic rays are crucial for understanding the origin and propagation of those energetic particles. The High Energy cosmic-Radiation Detection (HERD) facility onboard China`s Space Station, which is expected to operate in 2027, will push the direct measurements of cosmic ray fluxes precisely up to PeV energies. In this work, we investigate the potential of HERD on studying the propagation of cosmic rays using the measurements of boron, carbon, and oxygen spectra. We find that, compared with the current results, the new HERD measurements can improve the accuracy of the propagation parameters by 8\% to 40\%. The constraints on the injection spectra at high energies will also be improved.Comment: 10 pages, 4 figure

    Interlayer Coupling of Co/NM/FM(NiFe and Co) Nano-Sandwich Films

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    AbstractCu/Co, Cu/NiFe, Ta/NiFe bilayers and Co/Cu/Co, Co/Cu/NiFe, Co/Ta/NiFe sandwich films were deposited by a magnetron sputtering method. Magnetic properties were evaluated by VSM and spin valve magnet oresistance was investigated by a four-probe method to study the interlayer coupling of the two magnetic layers. It has been found that the interlayer coupling depended not only on the layer thickness of the nonmagnetic spacer but also on the nature of the spacer. The interlayer coupling was reduced as the spacer layer thickness increased. The result was consistent with those from observations of the magnetic domain for the trilayers by means of Lorentz Electron Microscope. The trilayers with Cu spacer layer have shown a stronger coupling than those with Ta spacer layer

    Visceral hyperalgesia induced by forebrain-specific suppression of native Kv7/KCNQ/M-current in mice

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    <p>Abstract</p> <p>Background</p> <p>Dysfunction of brain-gut interaction is thought to underlie visceral hypersensitivity which causes unexplained abdominal pain syndromes. However, the mechanism by which alteration of brain function in the brain-gut axis influences the perception of visceral pain remains largely elusive. In this study we investigated whether altered brain activity can generate visceral hyperalgesia.</p> <p>Results</p> <p>Using a forebrain specific αCaMKII promoter, we established a line of transgenic (Tg) mice expressing a dominant-negative pore mutant of the Kv7.2/KCNQ2 channel which suppresses native KCNQ/M-current and enhances forebrain neuronal excitability. Brain slice recording of hippocampal pyramidal neurons from these Tg mice confirmed the presence of hyperexcitable properties with increased firing. Behavioral evaluation of Tg mice exhibited increased sensitivity to visceral pain induced by intraperitoneal (i.p.) injection of either acetic acid or magnesium sulfate, and intracolon capsaicin stimulation, but not cutaneous sensation for thermal or inflammatory pain. Immunohistological staining showed increased c-Fos expression in the somatosensory SII cortex and insular cortex of Tg mice that were injected intraperitoneally with acetic acid. To mimic the effect of cortical hyperexcitability on visceral hyperalgesia, we injected KCNQ/M channel blocker XE991 into the lateral ventricle of wild type (WT) mice. Intracerebroventricular injection of XE991 resulted in increased writhes of WT mice induced by acetic acid, and this effect was reversed by co-injection of the channel opener retigabine.</p> <p>Conclusions</p> <p>Our findings provide evidence that forebrain hyperexcitability confers visceral hyperalgesia, and suppression of central hyperexcitability by activation of KCNQ/M-channel function may provide a therapeutic potential for treatment of abdominal pain syndromes.</p

    Global trends in COVID-19 Alzheimer's related research: a bibliometric analysis

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    BackgroundThe COVID-19 pandemic has significantly impacted public health, putting people with Alzheimer's disease at significant risk. This study used bibliometric analysis method to conduct in-depth research on the relationship between COVID-19 and Alzheimer's disease, as well as to predict its development trends.MethodsThe Web of Science Core Collection was searched for relevant literature on Alzheimer's and Coronavirus-19 during 2019–2023. We used a search query string in our advanced search. Using Microsoft Excel 2021 and VOSviewer software, a statistical analysis of primary high-yield authors, research institutions, countries, and journals was performed. Knowledge networks, collaboration maps, hotspots, and regional trends were analyzed using VOSviewer and CiteSpace.ResultsDuring 2020–2023, 866 academic studies were published in international journals. United States, Italy, and the United Kingdom rank top three in the survey; in terms of productivity, the top three schools were Harvard Medical School, the University of Padua, and the University of Oxford; Bonanni, Laura, from Gabriele d'Annunzio University (Italy), Tedeschi, Gioacchino from the University of Campania Luigi Vanvitelli (Italy), Vanacore, Nicola from Natl Ctr Dis Prevent and Health Promot (Italy), Reddy, P. Hemachandra from Texas Tech University (USA), and El Haj, Mohamad from University of Nantes (France) were the authors who published the most articles; The Journal of Alzheimer's Disease is the journals with the most published articles; “COVID-19,” “Alzheimer's disease,” “neurodegenerative diseases,” “cognitive impairment,” “neuroinflammation,” “quality of life,” and “neurological complications” have been the focus of attention in the last 3 years.ConclusionThe disease caused by the COVID-19 virus infection related to Alzheimer's disease has attracted significant attention worldwide. The major hot topics in 2020 were: “Alzheimer' disease,” COVID-19,” risk factors,” care,” and “Parkinson's disease.” During the 2 years 2021 and 2022, researchers were also interested in “neurodegenerative diseases,” “cognitive impairment,” and “quality of life,” which require further investigation

    High persistence rate of hepatitis B virus in a hydrodynamic injection-based transfection model in C3H/HeN mice

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    AIM: To optimize the viral persistence rate in a hydrodynamic injection (HI) based hepatitis B virus (HBV) transfection mouse model.METHODS: (1) 5-6-wk-old male C3H/HeN and C57BL/6 mice were hydrodynamically injected with 10 μg endotoxin-free pAAV/HBV1.2 plasmid DNA via the tail vein. Hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and HBV DNA, both in the serum and liver, were detected at different time points post HI by ELISA, immunohistochemical staining or quantitative polymerase chain reaction (PCR); (2) male C3H/HeN and C57BL/6 mice, either hydrodynamically injected mice at 10 wk post HI or naïve mice, were all immunized subcutaneously with 5 μg HBsAg formulated in complete Freund's adjuvant three times at a 2-wk interval. Two weeks after the final immunization, splenocytes were isolated for T cell function analysis by ELISPOT assay; and (3) five weeks post HI, C3H/HeN mice were intragastrically administered 0.1 mg/kg entecavir once a day for 14 d, or were intraperitoneally injected with 1 mg/kg interferon (IFN)-α twice a week for 2 wk, or were treated with PBS as controls. The sera were collected and assayed for HBV DNA on days 0, 7 and 14 after drug treatment.RESULTS: (1) Approximately 90% (22/25) of the injected C3H/HeN mice were still HBsAg-positive at 46 wk post HI, whereas HBsAg in C57BL/6 mice were completely cleared at 24 wk. Serum levels of HBeAg in C3H/HeN mice were higher than those in C57BL/6 mice from 4 wk to 46 wk. HBV DNA levels in the hydrodynamically injected C3H/HeN mice were higher than those in the C57BL/6 mice, both in the serum (from 4 wk to 46 wk) and in the liver (detected at 8 wk and 46 wk post HI). Histology showed that hepatitis B core antigen and HBsAg were expressed longer in the liver of C3H/HeN mice than in C57BL/6; (2) HBsAg specific T cell responses after HBsAg vaccination in hydrodynamically injected C3H/HeN and C57BL/6 mice, or naive control mice were detected by ELISPOT assay. After stimulation with HBsAg, the frequencies of IFN-γ producing splenocytes in the hydrodynamically injected C3H/HeN mice were significantly lower than those in hydrodynamically injected C57BL/6 mice, control C3H/HeN and control C57BL/6 mice, which were 0, 17 ± 7, 18 ± 10, and 41 ± 10 SFCs/10(6) splenocytes, respectively, and the mean spot sizes showed the same pattern. Even just stimulated with PMA and ionomysin, T-cell responses elicited in the vaccinated control C3H/HeN were much higher than those in hydrodynamically injected C3H/HeN mice; and (3) For drug treatment experiments on the hydrodynamically injected C3H/HeN mice, serum HBV DNA levels in the entecavir treatment group declined (131.2 folds, P &lt; 0.01) on day 7 after treatment and kept going down. In the group of IFN-α treatment, serum HBV DNA levels declined to a lowest point (6.42 folds, P &lt; 0.05) on 7 d after treatment and then rebounded.CONCLUSION: We have developed a novel HI-based HBV transfection model using C3H/HeN mice, which had a higher HBV persistence rate than the classic C57BL/6 mouse model.</p
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