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.

[Prevalence of frailty and related factors in middle-aged and elderly people in island and mountainous areas of Taizhou, Zhejiang Province].

Objective: To compare the prevalence of frailty and related factors in middle-aged and elderly people aged ≥45 years in island and mountainous areas of Taizhou, Zhejiang Province. Methods: Based on cross-sectional design, stratified cluster sampling and quota sampling methods were adopted. One administrative district was randomly selected from each of six coastal and three inland administrative districts in Taizhou during July to August, representing two different geographical terrains. In the island area (Jiaojiang District), all residents aged ≥45 years were included by cluster sampling. In the mountainous area (Xianju County), participants were selected through quota sampling, with same gender and age distributions. Data about their demographic characteristics, lifestyle and health-related factors were collected through questionnaire surveys and laboratory examinations. The prevalence of frailty was assessed using the Fried frailty phenotype scale. Hierarchical analysis and multivariate logistic regression analysis were used to compare the influencing factors of frailty. Results: A total of 1 011 local residents were studied, in whom island and mountainous residents accounted for 48.1% (486/1 011) and 51.9% (525/1 011) respectively; men and women accounted for 45.9% (464/1 011) and 54.1% (547/1 011) respectively. Middle-aged (45-49 years), younger elderly (60-74 years), and older elderly (≥75 years) residents accounted for 38.6% (390/1 011), 44.6% (451/1 011), and 16.8% (170/1 011) respectively. The overall prevalence rate of frailty was 3.6% (36/1 011), the prevalence rate was 3.7% (17/464) in men and 3.5% (19/547) in women. The prevalence rates in age groups 45-59,60-74 years and ≥75 years were 0.3% (1/390), 2.2% (10/451), and 14.7% (25/170), respectively. The prevalence rates of frailty and pre-frailty in island area were 6.0% (29/486) and 39.1% (190/486), respectively, which was higher than those in mountainous area (1.3%, 7/525) and (30.9%, 162/525). After adjusting for potential confounding factors, the risk for frailty in island residents was significantly higher than that in mountainous residents (aOR=1.55,95%CI: 1.07-2.25,P=0.019). In island area, older age (60-74 years:aOR=2.52,95%CI: 1.56-4.13; ≥75 years:aOR=11.65,95%CI:5.38-26.70), being women (aOR=1.94,95%CI: 1.20-3.17), suffering from depression (aOR=1.09,95%CI:1.02-1.17) were associated with frailty symptoms. In mountainous area, older age was also associated with an increased risk of frailty symptoms, but the OR value was lower than those in island area (60-74 years: aOR=1.74,95%CI:1.04-2.94;≥75 years: aOR=4.78,95%CI:2.45-9.50). Polydrug use (aOR=2.08,95%CI: 1.14-3.80) and suffering from depression (aOR=1.10,95%CI: 1.02-1.18) had significant positive association with frailty symptoms. Higher education level had significant negative association with frailty symptoms (junior high school: aOR=0.40,95%CI: 0.21-0.75; senior high school and technical secondary school: aOR=0.29,95%CI: 0.15-0.53; college or above:aOR=0.22,95%CI: 0.11-0.42). Conclusions: The prevalence of frailty in middle-aged and elderly community residents was significantly higher in island area than in mountainous area in Taizhou. The frailty-related factors varied with area. The elderly people (≥75 years) and women in island area had higher risk for frailty. Older age and suffering from depression were the independent risk factors for frailty. It is necessary to pay attention to the health risk factors and special environment in island area, and take comprehensive intervention measures to delay the process of debilitation and improve the quality of life of middle-aged and elderly people.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Reduced use of emergency care and hospitalization in patients with post-stroke cognitive impairment treated with traditional Chinese medicine.

BACKGROUND: The effect of traditional Chinese medicine (TCM) on the outcomes of dementia remains unclear. Our purpose is to compare the use of emergency care and hospitalization in patients with post-stroke cognitive impairment (PSCI) with or without treatment of TCM. METHODS: In a stroke cohort of 67 521 patients with PSCI aged over 40 years obtained from the 23 million people in Taiwan's national health insurance between 2000 and 2007, we identified 6661 newly diagnosed PSCI patients who were treated with TCM and 6661 propensity score-matched PSCI patients who were not treated with TCM. Under the control of immortal time bias, we calculated the adjusted rate ratios (RRs) and 95% CIs of the 1-year use of emergency care and hospitalization associated with TCM. RESULTS: The means of the emergency care medical visits (0.40 ± 0.98 vs. 0.47 ± 1.01, P = 0.0001) and hospitalization (0.72 ± 1.29 vs. 0.96 ± 1.49, P < 0.0001) were lower in the PSCI patients treated with TCM than in those without the TCM treatment. The RRs of emergency care and hospitalization associated with TCM were 0.87 (95% CI = 0.82-0.92) and 0.81 (95% CI = 0.78-0.84), respectively. The PSCI patients treated with a combination of acupuncture and herbal medicine had the lowest risk of emergency care visits and hospitalization. CONCLUSIONS: Our study raises the possibility that TCM use was associated with reduced use of emergency care and hospitalization after PSCI. However, further randomized clinical trials are needed to provide solid evidence of this benefit and identify the underlying mechanism.

Stroke in Parkinson's disease.

BACKGROUND: The association between Parkinson's disease (PD) and stroke remains completely understood. AIM: We aimed to investigate stroke risk and post-stroke outcomes in patients with PD. DESIGN: The retrospective cohort study included 1303 patients aged ≥ 40 years with new-diagnosed PD and 5212 non-PD adults were selected by frequency matching with age and sex in 2000-05. Both two groups were followed up until the end of 2013. Another nested stroke cohort study of 17 678 patients with stroke hospitalization in 2002-09 was conducted to compare the admission outcome in patients with and without PD history. METHODS: We collected patients' characteristics and medical conditions in the present two studies from claims data of Taiwan's National Health Insurance. Incidences and risks of stroke in people with and without PD during the follow-up period were calculated by adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) in the Cox proportional hazard model. Complications and mortality during the stroke admission associated with PD were analysed by calculating adjusted odds ratios (ORs) and 95% CIs in the logistic regressions. RESULTS: Incidences of stroke for people with and without PD were 19.8 and 9.93 per 1000 person-years, respectively, with corresponding HR of 1.96 (95% CI 1.67-2.30). History of PD was associated with post-stroke gastrointestinal bleeding (OR 1.25, 95% CI 1.05-1.49), epilepsy (OR 1.64, 95% CI 1.32-2.04), pneumonia (OR 1.34, 95% CI 1.20-1.49), urinary tract infection (OR 1.33, 95% CI 1.21-1.45) and mortality (OR 1.35, 95% CI 1.13-1.62). CONCLUSION: PD increases stroke risk and influences post-stroke outcomes.

Effects of red yeast rice prescription (LipoCol Forte) on adverse outcomes of surgery.

BACKGROUND: The influence of red yeast rice (RYR) on perioperative outcome remains unknown. AIM: We aimed to compare the complications and mortality after surgery between patients treated with and without RYR prescription. DESIGN: In this surgical cohort study of 3.6 million surgical patients who underwent major inpatient surgeries, 2581 patients who used RYR prescription pre-operatively were compared with 25 810 non-RYR patients selected by matching for age and sex. METHODS: Patients' demographics and medical conditions were collected from the claims data of the National Health Insurance in Taiwan. Complications and mortality after major surgeries in association with RYR prescription were investigated by calculating adjusted odds ratios (ORs) and 95% confidence intervals (CIs) by multiple logistic regression. RESULTS: Compared with patients without RYR prescription, patients prescribed RYR had lower risks of post-operative bleeding (OR 0.36, 95% CI 0.15-0.89), pneumonia (OR 0.54, 95% CI 0.36-0.83), stroke (OR 0.66, 95% CI 0.47-0.92) and 30-day in-hospital mortality (OR 0.37, 95% CI 0.15-0.92). Decreased risk of intensive care (OR 0.64, 95% CI 0.54-0.77), shorter length of hospital stay (P < 0.001) and lower medical expenditures (P = 0.0008) during the index surgical admission were also noted for patients with RYR prescription compared to those for patients without RYR prescription. CONCLUSIONS: This study showed a potentially positive effect of RYR on outcomes after major surgeries. However, patient non-compliance for taking medication should be noted. Our findings require future prospective studies to validate RYR prescription for improving perioperative outcomes.

IGFBP2 promotes vasculogenic mimicry formation via regulating CD144 and MMP2 expression in glioma.

Vasculogenic mimicry (VM) refers to the fluid-conducting channels formed by aggressive tumor cells rather than endothelial cells (EC) with elevated expression of genes associated with vascularization. VM has been considered as one of the reasons that glioblastoma becomes resistant to anti-VEGF therapy. However, the molecular basis underlying VM formation remains unclear. Here we report that the insulin-like growth factor-binding protein 2 (IGFBP2) acts as a potent factor to enhance VM formation in glioma. Evidence showed that elevated IGFBP2 expression was positively related with VM formation in patients with glioma. Enforced expression of IGFBP2 increased network formation of glioma cells in vitro by activating CD144 and MMP2 (Matrix Metalloproteinase 2). U251 cells with stable knockdown of IGFBP2 led to decreased VM formation and tumor progression in orthotopic mouse model. Mechanistically, IGFBP2 interacts with integrin α5 and ß1 subunits and augments CD144 expression in a FAK/ERK pathway-dependent manner. Luciferase reporter and ChIP assay suggested that IGFBP2 activated the transcription factor SP1, which could bind to CD144 promoter. Thus, IGFBP2 acts as a stimulator of VM formation in glioma cells via enhancing CD144 and MMP2 expression.

[Clinical observation of postprandial hypotension in patients with hypertensive and coronary heart disease].

Objective: To explore the prevalence and clinical characteristics of postprandial hypotension(PPH) in patients with essential hypertension and coronary heart disease. Methods: A total of 197 patients with essential hypertension and coronary heart disease, who had been treated in the First Department of Cardiology of the Second Hospital of Hebei Medical University from December, 2013 to December, 2014 were included. The patients' blood pressure before breakfast, lunch and dinner and 30, 60, 90, 120 minutes after the meal were monitored. Subjects were classified into PPH group (n=37) and non-PPH group (NPPH, n=160) according to postprandial decrease in systolic blood pressure, to explore the clinical characteristics and related factors and the major adverse cardiac and cerebral vascular events of PPH. Results: Among 197 patients, 37 cases (18.8%) showed at least once postprandial decline in systolic blood pressure greater than and equal to 20 mmHg. The incidence of PPH after breakfast and dinner were higher than lunch (P<0.05). There was no significant difference in the incidence of PPH among different age groups, among patients accompanied with different diseases, and among patients with different dining position (all P>0.05). According to the baseline systolic blood pressure, patients can be divided into 4 groups(<120 mmHg, 120-129 mmHg, 130-139 mmHg, >140 mmHg), the higher the level of the baseline systolic blood pressure was, the higher the incidence of PPH was. And the incidence of major adverse cardiac and cerebral vascular events in patients during hospitalization were increased by PPH. Conclusions: The prevalence of PPH in the patients with essential hypertension and coronary heart disease is 18.8%. The incidence of PPH after breakfast and dinner is higher than lunch. The baseline systolic blood pressure is considered to be the risk factor of PPH. And PPH could lead to an increase of the incidence of major adverse cardiac and cerebral vascular events.

Analysis of metabolic profiles of generalized aggressive periodontitis.

BACKGROUND AND OBJECTIVE: The specific pathogenesis of generalized aggressive periodontitis (GAgP) has not yet been clarified, and few studies have focused on the association between GAgP and metabolomics. To elucidate the roles of metabolic profiles in the status of GAgP, this study aimed to identify the differential metabolic profiles between patients with GAgP and healthy controls using an untargeted metabolomic profiling method. MATERIAL AND METHODS: Serum and gingival crevicular fluid samples were collected from healthy controls (n = 20) and patients with GAgP (n = 20) in this cross-sectional study. The relative levels of biomarkers in the samples were measured by gas chromatography-mass spectrometry. Principal components analysis and orthogonal partial least-squares discriminant analysis were used for statistical analysis. Metabolites were analysed qualitatively using the FiehnLib and NIST databases. Full-mouth probing depth and clinical attachment loss were recorded as indexes of periodontal disease. RESULTS: A total of 349 metabolites were qualitatively detected in the gingival crevicular fluid samples, and 200 metabolites were detected in the serum samples. Compared with healthy controls, patients with GAgP showed significant increases in serum urea and allo-inositol levels. In contrast, glutathione, 2,5-dihydroxybenzaldehyde, adipic acid and 2-deoxyguanosine levels were decreased in patients with GAgP. In the gingival crevicular fluid samples, noradrenaline, uridine, α-tocopherol, dehydroascorbic acid, xanthine, galactose, glucose-1-phosphate and ribulose-5-phosphate levels were increased in patients with GAgP, while thymidine, glutathione and ribose-5-phosphate levels were decreased. CONCLUSION: The metabolomics analysis by gas chromatography-mass spectrometry is an effective and minimally non-invasive way to differentiate the metabolites characteristic of patients with GAgP. Both serum and gingival crevicular fluid metabolomics are significantly different between patients with GAgP and healthy controls. These metabolic profiles have great potential in detecting GAgP and helping to understand its underlying mechanisms.

Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun.

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.