Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources.

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

Constraints on Ultraheavy Dark Matter Properties from Dwarf Spheroidal Galaxies with LHAASO Observations.

In this Letter we try to search for signals generated by ultraheavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible γ rays by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of the LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter that have low fluxes of astrophysical γ-ray background while having large amount of dark matter. By analyzing more than 700 days of observational data at LHAASO, no significant dark matter signal from 1 TeV to 1 EeV is detected. Accordingly we derive the most stringent constraints on the ultraheavy dark matter annihilation cross section up to EeV. The constraints on the lifetime of dark matter in decay mode are also derived.

Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A.

On 9 October 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time gamma-ray burst 221009A, recording the highest photon statistics in the TeV band ever obtained from a gamma-ray burst. We use this unique observation to place stringent constraints on the energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are E_{QG,1}>10 times the Planck energy E_{Pl} for the linear LIV effect, and E_{QG,2}>6×10^{-8}E_{Pl} for the quadratic LIV effect. Our limits on the quadratic LIV case improve previous best bounds by factors of 5-7.

Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A.

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A.

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO.

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations.

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9} GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies.

We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of π^{0}'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk.

Gamma-Ray Observation of the Cygnus Region in the 100-TeV Energy Region.

We report observations of gamma-ray emissions with energies in the 100-TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1, with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A.

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

First Detection of Photons with Energy beyond 100 TeV from an Astrophysical Source.

We report on the highest energy photons from the Crab Nebula observed by the Tibet air shower array with the underground water-Cherenkov-type muon detector array. Based on the criterion of a muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies E>100 TeV. As a result, we observed 24 photonlike events with E>100 TeV against 5.5 background events, which corresponds to a 5.6σ statistical significance. This is the first detection of photons with E>100 TeV from an astrophysical source.

[Effect and mechanism of MicroRNA-146a on TLR4 inflammatory signal pathway in the lung tissues of rats with mechanical ventilator-induced lung injury].

Objective: To investigate the effect and mechanism of microRNA-146a (miR-146a) on Toll-Like Receptor 4 (TLR4) inflammatory signal pathway in the lung tissues of rats with mechanical ventilator-induced lung injury. Methods: Thirty-two healthy male Sprague-Dawley rats were randomly divided into 4 groups (n=8 each): group A, normal control group, no mechanical ventilation, spontaneous breathing; group B, mechanical ventilation injury; group C, mechanical ventilation injury plus no-load virus transfection; group D, mechanical ventilation injury plus virus transfection; in group B, C, and D, mechanical ventilation were performed, respiratory rate was controlled at 80 beats/min, tidal volume was 40 ml/kg, inhaled oxygen concentration (FiO2) was 21%, inhalation/expiration ratio was 1∶2, positive end expiratory pressure ventilation (PEEP) was 0, each group were ventilated 4 hours daily, 7 days continuously to establish ventilator induced lung injury (VILI) rat model. Paraffin-embedded sections of lung tissue were stained with HE, the morphology and damage of lung tissue were observed under microscope. The lungs wet and dry ratio (W/D), the levels of inflammatory cytokines interleukin (IL)-1ß, IL-2 and tumor necrosis factor (TNF)-α were determined. Real-time PCR was used to detect the expression of TLR4 mRNA. The level of TLR4 protein was determined by Western blot. Results: The levels of lung tissue W/D and lung injury scores in group B (6.41±0.10, 11.38±0.92), group C (6.45±0.19, 11.75±1.04), group D (5.95±0.14, 7.53±4.78) were significantly increased than those in group A (4.33±0.08, 0.25±0.46), and in group D they were significantly decreased than group C (all P<0.01). The levels of IL-1ß, IL-2, TNF-α in group B[(36.07±4.28) pg/ml, (5.02±0.63) ng/ml, (382.57±35.41) ng/ml], group C[(35.82±5.47) pg/ml, (4.98±0.71) ng/ml, (375.13±36.95) ng/ml], group D[(27.01±3.18) pg/ml, (3.96±0.82) ng/ml, (297.56±39.08) ng/ml]were significantly increased than those in group A[(21.46±3.15) pg/ml, (2.45±0.17) ng/ml, (195.92±18.07) ng/ml], and in group D they were significantly decreased than group C (all P<0.01). The relative expression levels of TLR4 mRNA and TLR4 proteins in group B (29.57±5.10, 0.75±0.110), group C (27.27±4.72, 0.77±0.130), group D (12.89±2.58, 0.48±0.057) were significantly increased than those in group A (1.02±0.13, 0.18±0.025), and in group D they were significantly decreased than group C (all P<0.01). There was no significant difference of all the above indicators between group B and C (all P>0.05). Conclusions: MiR-146a can reduce acute lung inflammation and TLR4 expression in lungs of rats with mechanical ventilator-induced lung injury. MiR-146a may inhibit the inflammatory response through TLR4 signaling pathway.

[A clinican linical analysis of 29 cases of chronic pulmonary aspergillosis].

Objective: To improve the understanding of chronic pulmonary aspergillosis (CPA) by analyzing the clinical manifestations, imaging and pathological features, diagnosis, treatment and prognosis of this disease. Methods: Cases of CPA, proven by microbiological evidence based on pathological study in Fuzhou General Hospital of the People's Liberation Army and Affiliated Fuzhou City First Hospital of Fijian Medical University from January 2006 to October 2016 were retrospectively analyzed. Results: The patients consisted of 17 males and 12 females, aged 24 to 75 years, mean (42±16) years. The underlying disorders included post-tuberculosis infection (n=11), bronchiectasis (n=8), chronic obstructive pulmonary disease (n=3) and diabetes mellitus (n=2). The main clinical symptoms included productive cough (n=25), chronic sputum production (n=18) and hemoptysis (n=15). Serum GM antigen tests were performed in 19 cases, and the result was positive in 12 patients. BALF GM antigen tests were performed in 2 cases, both of which were positive. Chest CT showed that the lesions were located predominantly in the upper lobes (n=24). Single cavity with interior irregular intraluminal material (n=16) and multiple cavities with interior irregular intraluminal material (n=10) were the most frequent CT findings, while the "air crescent sign" was found in 13 cases. In the 22 patients who underwent surgical treatment, Aspergillus filaments were found in the cavity (n=20) or the bronchi (n=2) of lung samples, and histological examination didn't show tissue invasion by fungi. Surgical therapy was performed in 22 patients, with complete remission in 19 cases, and death in 3 cases. Anti-fungal therapy was administered in 6 patients, with partial remission in 4, and stable disease in 2 cases. One patient was not treated. Conclusions: CPA is more frequently seen in patients with underlying chronic pulmonary diseases. The common CT findings are single or multiple cavities with interior irregular intraluminal materials. Aspergillus filament in the cavity or bronchi of lung samples, without parenchymal invasion, is the proof of CPA. The surgical cure rate for simple aspergilloma and aspergillus nodule is high, while the risk of operation for chronic cavitary disease is high. GM antigen test may be an evidence for diagnosing CPA.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst.

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory (LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger and then rose to a peak ~10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle of ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

Peta-electron volt gamma-ray emission from the Crab Nebula.

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 1036 ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

SIRT3 retards intervertebral disc degeneration by anti-oxidative stress by activating the SIRT3/FOXO3/SOD2 signaling pathway.

OBJECTIVE: The objective of this paper is to determine whether SIRT3 could retard intervertebral disc degeneration and study the mechanism. MATERIALS AND METHODS: We chose the 3-month mice to establish intervertebral disc degeneration model and study the effect of SIRT3 on the intervertebral disc by Western blotting, quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), immunohistochemistry. Mouse nucleus pulposus cells were cultured to study the exact mechanism. RESULTS: The expression of SIRT3 was decreased in degenerated human nucleus pulposus. Intervertebral discs of mice treated with theacrine expressed more collagen II and less collagen X. In addition, nucleus pulposus cells stimulated with interleukin-1ß (IL-1ß) expressed less SIRT3 than that in the control group and nucleus pulposus cells with SIRT3 overexpress vectors expressed more collagen II FOXO3a and superoxide dismutase 2 (SOD2), indicating that SIRT3 could improve the intervertebral disc degeneration by anti-oxidative stress. CONCLUSIONS: SIRT3 is a protective factor for intervertebral discs and can reduce oxidative stress in the intervertebral disc.