Abstract
Many experiments have confirmed the spectral hardening at a few hundred GV of cosmic-ray (CR) nucleus spectra, and three general different origins have been proposed: the primary source ...acceleration, the propagation, and the superposition of different kinds of sources. The AMS-02 CR nucleus spectra of He, C, N, O, Ne, Mg, Si, and B (which includes B and its dominating parent species) are collected to study the necessity of employing a break in diffusion coefficient and independent breaks in primary source injection spectra to reproduce the spectral hardening at a few hundred GV. For comparison, three different schemes are introduced to do the global fitting. The fitting results show that both the break in diffusion coefficient and the independent breaks in primary source injection spectra are needed, which correspond to the spatially dependent propagation and the superposition of different kinds of sources, respectively. Consequently, the nucleus spectral hardening in a few hundred GV should have hybrid origins. Moreover, the CR spectral indices of He and Ne show large deviations from other species in the low-rigidity region, which indicates their different CR origins.
Critical patients with the coronavirus disease 2019 (COVID-19), even those whose nucleic acid test results had turned negative and those receiving maximal medical support, have been noted to progress ...to irreversible fatal respiratory failure. Lung transplantation (LT) as the sole therapy for end-stage pulmonary fibrosis related to acute respiratory distress syndrome has been considered as the ultimate rescue therapy for these patients.
From February 10 to March 10, 2020, three male patients were urgently assessed and listed for transplantation. After conducting a full ethical review and after obtaining assent from the family of the patients, we performed three LT procedures for COVID-19 patients with illness durations of more than one month and extremely high sequential organ failure assessment scores.
Two of the three recipients survived post-LT and started participating in a rehabilitation program. Pearls of the LT team collaboration and perioperative logistics were summarized and continually improved. The pathological results of the explanted lungs were concordant with the critical clinical manifestation, and provided insight towards better understanding of the disease. Government health affair systems, virology detection tools, and modern communication technology all play key roles towards the survival of the patients and their rehabilitation.
LT can be performed in end-stage patients with respiratory failure due to COVID-19-related pulmonary fibrosis. If confirmed positive-turned-negative virology status without organ dysfunction that could contraindicate LT, LT provided the final option for these patients to avoid certain death, with proper protection of transplant surgeons and medical staffs. By ensuring instant seamless care for both patients and medical teams, the goal of reducing the mortality rate and salvaging the lives of patients with COVID-19 can be attained.
Future large liquid-scintillator detectors can be implemented to observe neutrinos from a core-collapse supernova in our Galaxy in various reaction channels: (1) the inverse beta decay nu sub(e)+ pn+ ...e super(+), (2) the elastic neutrino-proton scattering nu + p arrow right nu+p, (3) the elastic neutrino-electron scattering nu+e super(-) arrow right nu+e super(-), (4) the charged-current nu sub(e) interaction nu sub(e)+ super(12) C arrow right e super(-)+ super(12) N, (5) the charged-current nu sub(e) interaction nu sub(e)+ super(12) C arrow right e super(+)+ super(12) B, and (6) the neutral-current interaction nu+ super(12) C arrow right nu+ super(12) C*. The less abundant super(13) C atoms in the liquid scintillator are also considered as a target, and both the charged-current interaction nu sub(e)+ super(13) C arrow right e super(-)+ super(13) N and the neutral-current interaction nu+ super(13) C arrow right nu+ super(13) C* are taken into account. In this work, we show for the first time that a global analysis of all these channels at a single liquid-scintillator detector, such as Jiangmen Underground Neutrino Observatory, is very important to test the average-energy hierarchy of supernova neutrinos and how the total energy is partitioned among neutrino flavors. In addition, the dominant channels for reconstructing neutrino spectra and the impact of other channels are discussed in great detail.
Information on the interiors of stars can be gleaned from their pulsations. Pulsation modes, which are determined by the internal state and structure of a star, are typically considered stable over ...short timescales. These independent pulsation modes have been used in asteroseismology to determine the interior structures of stars. Here, we report the discovery of peculiar pulsation mode interactions in the high-amplitude
δ
Scuti star KIC 6382916 (J19480292+4146558) that challenge the reliability of independent pulsation modes as indicators of a star’s internal structure. Through analysis of archival data, we find distinct variations in the amplitudes and frequencies of three independent pulsation modes and their harmonics and combinations over approximately 20 days. These variations can reach amplitudes of about 140% and frequency variations of about 12%. Correlation analysis of amplitude and frequency variations reveal additional pulsation mode interaction details and patterns. Notably, our findings regarding the phenomena related to the harmonics of independent pulsation modes challenge the traditional understanding in this area. These discoveries serve as cornerstones for future research and advance nonlinear asteroseismology.
The epidermal growth factor receptor (EGFR) plays important roles in multiple cellular events, including growth, differentiation, and motility. A major mechanism of downregulating EGFR function ...involves its endocytic transport to the lysosome. Sorting of proteins into intracellular pathways involves cargo adaptors recognizing sorting signals on cargo proteins. A dileucine-based sorting signal has been identified previously for the sorting of endosomal EGFR to the lysosome, but a cargo adaptor that recognizes this signal remains unknown. Here, we find that phosphoglycerate kinase 1 (PGK1) is recruited to endosomal membrane upon its phosphorylation, where it binds to the dileucine sorting signal in EGFR to promote the lysosomal transport of this receptor. We also elucidate two mechanisms that act in concert to promote PGK1 recruitment to endosomal membrane, a lipid-based mechanism that involves phosphatidylinositol 4,5-bisphosphate PI(4,5)P2 and a protein-based mechanism that involves hepatocyte growth factor receptor substrate (Hrs). These findings reveal an unexpected function for a metabolic enzyme and advance the mechanistic understanding of how EGFR is transported to the lysosome.
Abstract Harmonics are quite common in pulsating stars. They are always considered to mimic the behaviors of their independent parent pulsation modes, and are not taken for key information in ...asteroseismology. Here, we report an SX Phoenicis star XX Cygni, whose periodogram is dominated by the fundamental frequency f 0 = 7.41481 ± 0.00004 c day −1 and its 19 harmonics. According to the analysis of the archival data from the Transiting Exoplanet Survey Satellite (TESS), we find that both the amplitudes and frequencies of the fundamental mode and the harmonics vary within TESS Sectors 14–17 and 54–57, which might be caused by the contamination of neighboring stars. What is more interesting is that the harmonics show significantly uncorrelated amplitude and frequency variations over time. Some possible origins and interesting issues are proposed to scheme further research of this hidden corner in current asteroseismology.
Cosmic ray (CR) physics has entered a precision-driven era. With the latest AMS-02 nuclei data (boron-to-carbon ratio, proton flux, helium flux, and antiproton-to-proton ratio), we perform a global ...fitting and constrain the primary source and propagation parameters of cosmic rays in the Milky Way by considering 3 schemes with different data sets (with and without p¯/p data) and different propagation models (diffusion-reacceleration and diffusion-reacceleration-convection models). We find that the data set with p¯/p data can remove the degeneracy between the propagation parameters effectively and it favors the model with a very small value of convection (or disfavors the model with convection). The separated injection spectrum parameters are used for proton and other nucleus species, which reveal the different breaks and slopes among them. Moreover, the helium abundance, antiproton production cross sections, and solar modulation are parametrized in our global fitting. Benefited from the self-consistence of the new data set, the fitting results show a little bias, and thus the disadvantages and limitations of the existed propagation models appear. Comparing to the best fit results for the local interstellar spectra (ϕ=0) with the VOYAGER-1 data, we find that the primary sources or propagation mechanisms should be different between proton and helium (or other heavier nucleus species). Thus, how to explain these results properly is an interesting and challenging question.
Polymer graftings (PGs) are widely employed in antifouling surfaces and drug delivery systems to regulate the interaction with a foreign environment. Through molecular dynamics simulations and ...scaling theory analysis, we investigate the physical antifouling properties of PGs via their collision behaviors. Compared with mushroom-like PGs with low grafting density, we find brush-like PGs with high grafting density could generate large deformation-induced entropic repulsive force during a collision, revealing a microscopic mechanism for the hop motions of polymer-grafted nanoparticles for drug delivery observed in experiment. In addition, the collision elasticity of PGs is found to decay with the collision velocity by a power law, i.e., a concise dynamic scaling despite the complex process involved, which is beyond expectation. These results elucidate the dynamic interacting mechanism of PGs, which are of immediate interest for a fundamental understanding of the antifouling performance of PGs and the rational design of PG-coated nanoparticles in nanomedicine for drug delivery.
Major depressive disorder (MDD) is common and disabling, but its neuropathophysiology remains unclear. Most studies of functional brain networks in MDD have had limited statistical power and data ...analysis approaches have varied widely. The REST-meta-MDD Project of resting-state fMRI (R-fMRI) addresses these issues. Twenty-five research groups in China established the REST-meta-MDD Consortium by contributing R-fMRI data from 1,300 patients with MDD and 1,128 normal controls (NCs). Data were preprocessed locally with a standardized protocol before aggregated group analyses. We focused on functional connectivity (FC) within the default mode network (DMN), frequently reported to be increased in MDD. Instead, we found decreased DMN FC when we compared 848 patients with MDD to 794 NCs from 17 sites after data exclusion. We found FC reduction only in recurrent MDD, not in first-episode drug-naïve MDD. Decreased DMN FC was associated with medication usage but not with MDD duration. DMN FC was also positively related to symptom severity but only in recurrent MDD. Exploratory analyses also revealed alterations in FC of visual, sensory-motor, and dorsal attention networks in MDD. We confirmed the key role of DMN in MDD but found reduced rather than increased FC within the DMN. Future studies should test whether decreased DMN FC mediates response to treatment. All R-fMRI indices of data contributed by the REST-meta-MDD consortium are being shared publicly via the R-fMRI Maps Project.
Based on the precise nuclei data released by AMS-02, we study the spectra hardening of both the primary (proton, helium, carbon, oxygen, and the primary component of nitrogen) and the secondary ...(anti-proton, lithium, beryllium, boron, and the secondary component of nitrogen) cosmic-ray (CR) nuclei. With the diffusion-reacceleration model, we consider two schemes to reproduce the hardening in the spectra: (i) a high-rigidity break in primary source injection; and (ii) a high-rigidity break in diffusion coefficient. The global fitting results show that both schemes could reproduce the spectra hardening in the current status. More precise multi-TV data (especially the data of secondary CR species) is needed if one wants to distinguish these two schemes. In our global fitting, each of the nuclei species is allocated an independent solar-modulation potential and a rescale factor (which accounts for the isotopic abundance for primary nuclei species and uncertainties of production cross section or inhomogeneity of CR sources and propagation for secondary nuclei species). The fitting values of these two parameter classes show us some hints on some new directions in CR physics. All the fitted rescale factors of primary nuclei species have values that are systematically smaller than 1.0, while that of secondary nuclei species are systematically larger than 1.0. Moreover, both the rescale factor and solar-modulation potential of beryllium have values that are obviously different from other species. This might indicate that beryllium has the specificity not only on its propagation in the heliosphere, but also on its production cross section. All these new results should be seriously studied in the future.
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