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1.
Phys Rev Lett ; 132(13): 131002, 2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38613275

RESUMEN

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.

2.
Phys Rev Lett ; 131(15): 151001, 2023 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-37897763

RESUMEN

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.

3.
Science ; 380(6652): 1390-1396, 2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37289911

RESUMEN

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.

4.
Bull Exp Biol Med ; 173(3): 346-353, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35852692

RESUMEN

We studied an amorphous solid dispersion of berberine with absorption enhancer sodium caprate (Huang-Gui solid dispersion preparations, HGSD). A therapeutic effect of HGSD was revealed in mice with type 2 diabetes mellitus and palmitate-induced injury to MIN6 ß-cells. HGSD treatment (150 mg/kg) improved glucose metabolism and decreased ß-cell apoptosis in diabetic mice. Furthermore, the effective component of HGSD berberine significantly attenuated the palmitate-induced decrease in MIN6 ß-cells viability and insulin secretion. Moreover, molecular docking analysis and Western blotting showed that berberine decreased cell apoptosis and expression of group VIA phospholipase A2 (iPLA2), p38 mitogen-activated protein kinase (p38 MAPK), and caspase-3. These data suggest that HGSD treatment protected ß-cells via inhibiting the iPLA2/p38 MAPK pathway.


Asunto(s)
Berberina , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Islotes Pancreáticos , Animales , Apoptosis , Berberina/farmacología , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Células Secretoras de Insulina/metabolismo , Ratones , Simulación del Acoplamiento Molecular , Palmitatos/metabolismo , Palmitatos/farmacología , Palmitatos/uso terapéutico , Fosfolipasas/metabolismo , Fosfolipasas/farmacología , Fosfolipasas/uso terapéutico , Fosfolipasas A2 Calcio-Independiente/metabolismo , Fosfolipasas A2 Calcio-Independiente/farmacología , Proteínas Quinasas p38 Activadas por Mitógenos/genética , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
5.
Phys Rev Lett ; 128(5): 051102, 2022 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-35179919

RESUMEN

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.

6.
Phys Rev Lett ; 129(26): 261103, 2022 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-36608208

RESUMEN

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.

7.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(10): 1232-1239, 2021 Oct 06.
Artículo en Chino | MEDLINE | ID: mdl-34706510

RESUMEN

To investigate Streptococcus suis (S.suis) isolated from patients in Shandong province using genomic epidemiology and pathogenologic analysis. To provide the foundation to establish reasonable and accurate prevention and control measures of human S. suis infection. Molecular typing, whole genome phylogenetic tree, virulence gene typing, antibiotic resistance profile and mobile genetic elements carrying antibiotic resistance genes of isolated S. suis strains were investigated. The pathogenicity of isolated strains was also evaluated by comparing their capacity to induce pro-inflammatory cytokine production in vitro. S. suis infections in Shandong province were predominantly due to serotype 2 and sequence type 1 strains. The major symptoms were meningitis. The studied strains could be divided into five lineages. All strains belong to highly pathogenic type in Shandong province,Strains from lineage 2 possessed higher capacity to stimulate pro-inflammatory cytokine production than other strains did, even though other strains belong to highly pathogenic strains. In addition, multiple antibiotic resistance genes and corresponding mobile genetic elements werewidespread in S. suis strains from Shandong province, except strains from lineage 3. High diversities in genome, evolutionary path and pathogenicity of S. suis strains from Shandong province were revealed. It was necessary to surveillant the S. suis strain in genomic level.


Asunto(s)
Infecciones Estreptocócicas , Streptococcus suis , Genómica , Humanos , Filogenia , Infecciones Estreptocócicas/epidemiología , Streptococcus suis/genética , Virulencia/genética
8.
Phys Rev Lett ; 127(3): 031102, 2021 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-34328784

RESUMEN

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.

9.
Science ; 373(6553): 425-430, 2021 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-34261813

RESUMEN

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.

10.
Phys Rev Lett ; 126(24): 241103, 2021 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-34213924

RESUMEN

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.

11.
Phys Rev Lett ; 126(20): 201102, 2021 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-34110215

RESUMEN

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

12.
Nature ; 594(7861): 33-36, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34002091

RESUMEN

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.

13.
Phys Rev Lett ; 126(14): 141101, 2021 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-33891464

RESUMEN

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.

14.
Eur Rev Med Pharmacol Sci ; 24(1): 65-73, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31957819

RESUMEN

OBJECTIVE: To clarify the potential function of miRNA-96 in accelerating the malignant progression of ovarian cancer (OC) and its underlying mechanism. PATIENTS AND METHODS: The expression patterns of miRNA-96 in 36 matched OC tissues and adjacent normal tissues were determined by qRT-PCR. We analyzed the correlation between the miRNA-96 level and the clinical parameters of OC patients. Subsequently, the cellular levels of miRNA-96 in OC cell lines were determined as well. To construct miRNA-96 inhibitor and NC, the regulatory effects of miRNA-96 on the proliferative and migratory abilities in OC cells were examined. The target gene of miRNA-96 was verified by Dual-Luciferase Reporter Gene Assay. Finally, the rescue experiments were conducted to clarify the regulatory role of miRNA-96/FOXO3a axis in the malignant progression of OC. RESULTS: MiRNA-96 was upregulated in OC tissues relative to adjacent normal ones. Compared with OC patients presenting high-level of miRNA-96, those with low-level miRNA-96 suffered more advanced tumor staging and a worse overall survival. The transfection of miRNA-96 inhibitor markedly attenuated proliferative and migratory abilities in SKOV3 and CAOV3 cells. In addition, FOXO3a was identified to be the target gene of miRNA-96, which was negatively regulated by miRNA-96. FOXO3a exerted a lower abundance in OC tissues relative to adjacent normal ones. Finally, the rescue experiments revealed that FOXO3a knockdown could abolish the inhibitory role of miRNA-96 knockdown in the proliferative, migratory, and invasive abilities in OC cells. CONCLUSIONS: The knockdown of miRNA-96 attenuated the proliferative and migratory abilities in OC cells by targeting FOXO3a. We believed that miRNA-96 accelerates the malignant progression of OC, which could be utilized as a therapeutic target in clinical application.


Asunto(s)
Proteína Forkhead Box O3/metabolismo , MicroARNs/metabolismo , Neoplasias Ováricas/metabolismo , Proliferación Celular/genética , Células Cultivadas , Femenino , Proteína Forkhead Box O3/genética , Humanos , MicroARNs/genética , Persona de Mediana Edad , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología
15.
Sci Adv ; 5(9): eaax3793, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31799401

RESUMEN

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 1/2 years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

16.
Phys Rev Lett ; 123(5): 051101, 2019 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-31491288

RESUMEN

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.

17.
Zhonghua Shao Shang Za Zhi ; 35(1): 71-73, 2019 Jan 20.
Artículo en Chino | MEDLINE | ID: mdl-30678406

RESUMEN

In March 2017, a severely burned male patient aged 36 years with hypovolemic shock was admitted to our hospital. The patient received large quantities of antibiotics and blood products and repeated skin graft after admission, and then he suffered wound errhysis and throat congestion. The patient was healthy before without family history of bleeding or thrombosis disease. Laboratory tests showed that prothrombin time and activated partial coagulation time were remarkably prolonged, blood coagulation factor Ⅴ activity was extremely low, and the result of qualitative test of coagulation factor inhibitor was positive. Acquired blood coagulation factor Ⅴ deficiency was diagnosed. After application of dexamethasone (5 mg, twice per day) and infusion of fresh frozen plasma, blood coagulation indicators of patients recovered in 4 days, the result of qualitative test of coagulation factor inhibitor was negative, and bleeding symptoms were improved.


Asunto(s)
Inhibidores de Factor de Coagulación Sanguínea/sangre , Coagulación Sanguínea , Quemaduras/terapia , Factor V/antagonistas & inhibidores , Hemorragia/sangre , Trasplante de Piel , Adulto , Pruebas de Coagulación Sanguínea/métodos , Quemaduras/complicaciones , Humanos , Masculino , Choque , Resultado del Tratamiento
18.
Phys Rev Lett ; 120(3): 031101, 2018 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-29400499

RESUMEN

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

19.
Phys Rev Lett ; 111(1): 011101, 2013 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-24027782

RESUMEN

We report on a clear solar-cycle variation of the Sun's shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun's shadow, using the potential field source surface model and the current sheet source surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun's shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun's shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun's shadow observed in the TeV cosmic-ray flux.

20.
Water Sci Technol ; 63(10): 2138-42, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21977631

RESUMEN

The application of reversed A2/O process in practice in China is mainly discussed in this paper. As a new process on nitrogen and phosphorus removal, principle and technical features of reversed A2/O process are also summarized. The application in rebuilt wastewater treatment plant shows that reversed A2/O process not only has merits on high nitrogen and phosphorus removal efficiency, but also has merits on energy saving. The application in newly-build wastewater treatment plant shows that infrastructure and equipment investment of reversed A2/O process economized 15% and 10% respectively, compared to conventional A2/O process. The practical application shows that reversed A2/O process is a new nitrogen and phosphorus removal process, which is suitable for China's national conditions.


Asunto(s)
Nitrógeno/aislamiento & purificación , Fósforo/aislamiento & purificación , Administración de Residuos/métodos , Contaminantes Químicos del Agua/aislamiento & purificación , China
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