Evidence for particle acceleration approaching PeV energies in the W51 complex

The γ-ray emission from the W51 complex is widely acknowledged to be attributed to the interaction between the cosmic rays (CRs) accelerated by the shock of supernova remnant (SNR) W51C and the dense molecular clouds in the adjacent star-forming region, W51B. However, the maximum acceleration capability of W51C for CRs remains elusive. Based on observations conducted with the Large High Altitude Air Shower Observatory (LHAASO), we report a significant detection of γ rays emanating from the W51 complex, with energies from 2 to 200 TeV. The LHAASO measurements, for the first time, extend the γ-ray emission from the W51 complex beyond 100 TeV and reveal a significant spectrum bending at tens of TeV. By combining the "π0-decay bump" featured data from Fermi-LAT, the broadband γ-ray spectrum of the W51 region can be well-characterized by a simple pp-collision model. The observed spectral bending feature suggests an exponential cutoff at ∼400 TeV or a power-law break at ∼200 TeV in the CR proton spectrum, most likely providing the first evidence of SNRs serving as CR accelerators approaching the PeV regime. Additionally, two young star clusters within W51B could also be theoretically viable to produce the most energetic γ rays observed by LHAASO. Our findings strongly support the presence of extreme CR accelerators within the W51 complex and provide new insights into the origin of Galactic CRs.

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.

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.

Improved diet-based nutritional interventions can improve childhood obesity with the synergistic regulation of gut microbiota

Childhood obesity is a crucial public health concern worldwide. Dietary intervention is the most common intervention for the treatment of obesity. Therefore, we tested an improved diet-based nutritional interventions to improve the childhood obesity and its gut microbiota. Thirty obese children received a 12-week intervention with the adjust-energy-restricted dietary pattern (A-CRD). Body composition was measured by bioelectrical impedance (Inbody S10) and faecal microbes were profiled by sequencing 16S rRNA. Compared to the NTB group (at 0 week), the NTA group (at 12 weeks) had a significantly greater decrease in body weight, body mass index (BMI) and percent body fat (PBF) ( P < 0.001, respectively), whereas skeletal muscle mass (SMM) and fat free mass (FFM) were not statistically significantly different ( P > 0.05). The gut microbiota was found significantly different between the NTB and NTA groups based on alpha and beta diversity. Bifidobacterium, Blautia, and Streptococcus was significantly increased, whereas Bacteroides and Megamonas was significantly decreased in the NTA group ( P < 0.05, respectively). Meanwhile, NTA group significantly increased the ability to produce short-chain fatty acids (SCFAs; e.g. acetic acid/total dietary energy) and changed he predictive metabolic functional features of the microbiota communities ( P < 0.05, respectively) than the NTB group. In conclusion, A-CRD can significantly improve childhood obesity, and the underlying mechanism may be its effect on gut microbiota and metabolism. Therefore, the diet-based nutrition intervention targeting gut microbiota will be more effective management of body weight and prevention of obesity. Chinese Clinical Trial Register: ChiCTR2300074571.

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.

Resveratrol Attenuates Rheumatoid Arthritis Induce Neutrophil Extracellular Traps via TLR-4 Mediated Inflammation in C57BL/6 Mice

The objective of this study was to evaluate whether RSV inhibits neutrophil extracellular traps (NETs) that induce joint hyperalgesia in C57BL/6 mice after adjuvant-induced arthritis. A subplantar injection of Freund's complete adjuvant was administered to C57BL/6 mice on day 0 for immunization in the AIA model. Resveratrol (RSV, 25 mg/kg) was administered intraperitoneally once daily starting on day 22 and continuing for two weeks. The effects of mechanical hyperalgesia and edema formation have been assessed in addition to histopathological scoring. Mice were sacrificed on day 35 to determine cytokine levels and PADI4 and COX-2 expression levels. ELISA was used to quantify neutrophil extracellular traps (NETs) along with neutrophil elastase-DNA and myeloperoxidase-DNA complexes in neutrophils. An immunohistochemical stain was performed on knee joints to determine the presence of nuclear factor kappa B p65 (NF-kappaB p65). AIA mice were found to have higher levels of NET in joints and their joint cells demonstrated an increased expression of the PADI4 gene. Treatment with RSV in AIA mice (25 mg/kg, i.p.) significantly (P<0.05) inhibited joint hyperalgesia, resulting in a significant increase in mechanical threshold, a decrease in articular edema, a decrease in the production of inflammatory cytokines, increased COX-2 expression, and a decrease in the immunostaining of NF-kappaB. Furthermore, treatment with RSV significantly reduced the amount of neutrophil elastase (NE)-DNA and MPO-DNA complexes, which were used as indicators of NET formation (P<0.05). This study indicates that RSV reduces NET production and hyperalgesia by reducing inflammation mediated by PADI4 and COX-2. According to these data, NETs contribute to joint pain and resveratrol can be used to treat pain in RA through this pathway.

An ultrahigh-energy γ-ray bubble powered by a super PeVatron

We report the detection of a γ-ray bubble spanning at least 100deg2 in ultra-high energy (UHE) up to a few PeV in the direction of the star-forming region Cygnus X, implying the presence super PeVatron(s) accelerating protons to at least 10 PeV. A log-parabola form with the photon index Γ(E)=(2.71±0.02)+(0.11±0.02)×log10(E/10TeV) is found fitting the gamma-ray energy spectrum of the bubble well. UHE sources, "hot spots" correlated with very massive molecular clouds, and a quasi-spherical amorphous γ-ray emitter with a sharp central brightening are observed in the bubble. In the core of ∼0.5°, spatially associating with a region containing massive OB association (Cygnus OB2) and a microquasar (Cygnus X-3), as well as previously reported multi-TeV sources, an enhanced concentration of UHE γ-rays is observed with 2 photons at energies above 1 PeV. The general feature of the bubble, the morphology, and the energy spectrum, are reasonably reproduced by the assumption of a particle accelerator in the core, continuously injecting protons into the ambient medium.

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.

[The safety and efficacy of prophylactic hyperthermic intraperitoneal chemotherapy for elderly patients with locally advanced gastric cancer: a propensity score matching analysis]

Objective: To evaluate the safety and efficacy of prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC) on elderly patients diagnosed with locally advanced gastric cancer based on a propensity score matching analysis. Methods: Clinical data of elderly patients with locally advanced gastric cancer who underwent radical gastrectomy in Beijing Hospital from January 2017 to December 2021 were retrospectively collected. According to whether HIPEC was used, the patients were divided into HIPEC group (radical gastrectomy combined with HIPEC) and control group (radical gastrectomy alone), and 29 patients in HIPEC group and 122 patients in control group. After 1∶1 matching of PSM, there were 28 patients in each group. The clinicopathological data, surgical data, postoperative recovery and long-term survival of the two groups were compared and analyzed. Results: Before PSM, the mean age in the HIPEC group was (70.7±4.0) years, and in the control group was (73.1±5.8) years (P=0.011). After PSM, the mean age in the HIPEC group was (70.9±3.9) years, and it was (71.8±5.4) years in the control group (P=0.739). Before PSM, the incidence of postoperative complications was 20.7% (6 cases) in the HIPEC group and 26.2% (32 cases) in the control group (P=0.639). After PSM, the incidence of postoperative complications was 21.4% (6 cases) in the HIPEC group and 14.3% (4 cases) in the control group (P=0.730). Before PSM, the mean duration of hospitalization after radical gastrectomy was (13.6±7.6) days in HIPEC group and (16.2±13.0) days in control group, respectively (P=0.312). After PSM, the mean duration of hospitalization after radical gastrectomy was (13.7±7.8) days in HIPEC group and (15.4±9.7) days in control group, respectively (P=0.479). Before PSM, the 1-and 3-year overall survival rates of the HIPEC group were 88.2% and 69.7%, and 88.0% and 66.1% for control group, respectively, with no statistical difference between the two groups in overall survival (P=0.499). After PSM, the 1-and 3-year overall survival rates of the HIPEC group were 86.8% and 69.7%, and 93.1% and 67.5% for control group, respectively, with no statistical difference between the two groups in overall survival (P=0.425). Before PSM, the 1-and 3-year disease-free survival rates of the HIPEC group were 88.2% and 67.1%, and 87.8% and 64.3% for control group, respectively, with no statistical difference between the two groups in disease-free survival (P=0.863). After PSM, the 1-and 3-year disease-free survival rates of the HIPEC group were 88.2% and 62.8%, and 93.7% and 64.7% for control group, respectively, with no statistical difference between the two groups in disease-free survival (P=0.804). Conclusions: Radical surgery combined with HIPEC for elderly patients with gastric cancer does not increase postoperative complications and postoperative recovery time. However, there was no significant difference in overall survival and disease-specific survival between the two groups.

[Analysis of prognosis and related factors in oldest-old patients with left-side or right-side colon cancer after hemicolectomy]

Objective: This study aimed to explore the difference of prognosis in oldest-old colon cancer patients between the left-side and right-side hemicolectomy. Methods: A total of 238 oldest-old (≥75 years old) colon cancer patients who received surgical treatment in Gastrointestinal Surgery Department of Beijing Hospital from December 2010 to December 2020 were retrospectively collected. They were divided into right-side hemicolectomy (RCC) group (130 cases) and left-side hemicolectomy (LCC) group (108 cases) by surgical methods. The difference in postoperative short-term complications and long-term prognosis was compared between the two groups, and the related factors of postoperative death was analyzed using multivariate Cox regression model. Results: The age of 238 oldest-old patients with colon cancer ranged from 75 to 93 years old (80.5±3.7). There were 128 males and 110 females. The ages of patients in the LCC group and RCC group were (80.4±3.7) and (80.6±3.7) years old (P=0.699), respectively. There was no significant difference in gender, body mass index (BMI) and co-existing chronic diseases between two groups (P>0.05). The proportion of the duration of surgery exceeding 170 min in the LCC group was significantly higher than that in the RCC group (56.5% vs 43.1%, P=0.039). The incidence of postoperative short-term complications in RCC group was slightly higher than LCC group (P>0.05), and there was no significant difference in overall survival (OS), tumor-specific survival (CSS) and disease-free survival (DFS) between two groups. However, the two groups had different prognostic risk factors, pathological Ⅳ stage (HR=28.970,95%CI:1.768-474.813,P=0.018), intraoperative bleeding (HR=2.297,95%CI:1.351-3.907,P=0.002) and cancer nodules (HR=2.044,95%CI:1.047-3.989,P=0.036) were independent prognostic risk factors in LCC group. Underweight (HR=0.428,95%CI:0.192-0.955,P=0.038), overweight(HR=0.316,95%CI:0.125-0.800,P=0.015),obesity (HR=0.211,95%CI:0.067-0.658,P=0.007), lymph node metastasis (HR=2.682,95%CI:1.497-4.807,P=0.001), tumor nodule (HR=2.507,95%CI:1.301-4.831,P=0.027) and postoperative length of stay of 9 days (HR=1.829,95%CI:1.070-3.128,P=0.006) were independent risk factors for poor prognosis in RCC group. Conclusions: The duration of surgery of oldest-old colon cancer patients in the LCC group was longer than that in the RCC group. However, there was no significant difference in the incidence of postoperative complications between the two groups. High pathological stage, more intraoperative bleeding and cancer nodules were independent prognostic risk factors in the LCC group. Abnormal BMI, lymph node metastasis, cancer nodules and postoperative length of stay were independent risk factors for poor prognosis in the RCC group.

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 of the bright GRB 221009A, which serendipitously occurred within the instrument 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, then rose to a peak about 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 ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

Spike height improves prediction of future seizure risk

OBJECTIVE

We evaluated whether interictal epileptiform discharge (IED) rate and morphological characteristics predict seizure risk.

METHODS

We evaluated 10 features from automatically detectable IEDs in a stereotyped population with self-limited epilepsy with centrotemporal spikes (SeLECTS). We tested whether the average value or the most extreme values from each feature predicted future seizure risk in cross-sectional and longitudinal models.

RESULTS

10,748 individual centrotemporal IEDs were analyzed from 59 subjects at 81 timepoints. In cross-sectional models, increases in average spike height, spike duration, slow wave rising slope, slow wave falling slope, and the most extreme values of slow wave rising slope each improved prediction of an increased risk of a future seizure compared to a model with age alone (p < 0.05, each). In longitudinal model, spike rising height improved prediction of future seizure risk compared to a model with age alone (p = 0.04) CONCLUSIONS: Spike height improves prediction of future seizure risk in SeLECTS. Several other morphological features may also improve prediction and should be explored in larger studies.

SIGNIFICANCE

Discovery of a relationship between novel IED features and seizure risk may improve clinical prognostication, visual and automated IED detection strategies, and provide insights into the underlying neuronal mechanisms that contribute to IED pathology.

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.

A high-performance and stable Cu/Beta for adsorption-catalytic oxidation in-situ destruction of low concentration toluene

Finding a cost-effective treatment to remove of low concentrations of volatile organic compounds (VOCs) is still a challenge. In this study, a Cu/Beta material was developed for in situ adsorption-catalytic oxidation of low concentrations of toluene. The results showed that the addition of Cu enhanced the adsorption and catalytic oxidation of toluene by Beta zeolite. Cu7/Beta with a Cu⁺ ratio of close to 50% performed best. The high adsorption of Cu7/Beta was mainly attributed to the abundant Cu⁺ species and the micro-mesoporous structure of the Beta zeolite, and the high catalytic oxidation was attributed to the lattice oxygen in the uniformly dispersed CuO. Finally, the adsorption intermediates and reaction pathways in the catalytic oxidation of toluene were clarified using XPS and DRIFTS spectra. This work provides new strategies for the development of efficient and stable adsorption-catalytic oxidation in situ destruction materials.

Characteristics of Radiation-Related Intracranial Aneurysms: A Multicenter Retrospective Study

BACKGROUND AND PURPOSE

Intracranial aneurysms, a rare complication of radiation therapy, have been reported mainly in case reports or case series. We performed a multicenter, retrospective cohort study to investigate the characteristics of radiation-induced intracranial aneurysms.

MATERIALS AND METHODS

Data on 2641 patients with intracranial aneurysms were retrospectively collected from 3 hospitals between January 2005 and June 2014. An additional 1519 patients were recruited from a single center between July 2014 and March 2020. Aneurysms in patients with a history of radiation therapy for at least 6 months were defined as radiation-related aneurysms. Patients' demographic profiles, clinical characteristics, and aneurysm parameters detected on CTA were compared between radiation-related and control groups.

RESULTS

Of the 4160 patients, the average age was 57.9 (SD, 13.5) years, 2406 (57.8%) were women, 477 (11.5%) had multiple aneurysms, 3009 (72.3%) had SAH, and 34 (0.8%) had radiation-related aneurysms. The male-to-female ratio in the radiation-related group was significantly higher than that in the control group (2.4:1 versus 0.72:1, P = .001). The mean age of the radiation-related group was significantly younger than in the control group (51.4 [SD, 15.0] years versus 58.2 [SD, 13.5] years, P = .003). More patients in the radiation-related group presented with SAH than in the control group (without age and sex matching, 88.2% versus 72.2%, P = .037; with age and sex matching, 88.2% versus 58.8%, P = .006). Of the 4813 intracranial aneurysms, only 43 (0.9%) aneurysms were categorized as in the radiation-related group, whereas 4770 (99.1%) aneurysms constituted the control group. Compared with the control group, there was a significantly higher proportion of sidewall aneurysms (46.5% versus 32.3%, P = .048) and a predilection for aneurysms involving the ICA and posterior circulation arteries (72.1% versus 52.2%, P = .046) in the radiation-related group.

CONCLUSIONS

Compared with the control group, radiation-related aneurysms are more prone to occur in men and young patients, with a higher percentage of sidewall aneurysms located in the ICA and posterior circulation arteries. Furthermore, SAH is highly prevalent in patients with radiation-induced aneurysms, indicating that dedicated screening for aneurysms after radiation therapy is necessary, but further studies are needed to determine when and how to screen.

Cu-VWT Catalysts for Synergistic Elimination of NOx and Volatile Organic Compounds from Coal-Fired Flue Gas

A dual-function catalyst, designated as Cu5-VWT, has been constructed for the synergistic removal of NO_x and volatile organic compounds under complex coal-fired flue gas conditions. The removal of toluene, propylene, dichloromethane, and naphthalene all exceeded 99% (350 °C), and the catalyst could effectively block the generation of polycyclic aromatic hydrocarbons. Mechanistic studies have shown that Cu sites on the Cu5-VWT catalyst facilitate catalytic oxidation, while V sites facilitate NO_x reduction. Thus, toluene oxidation and NO_x reduction can proceed simultaneously. The removal of total hydrocarbons and nonmethane total hydrocarbons from 1200 m³·h^-1 real coal-fired flue gas by a monolithic catalyst were determined as 92 and 96%, respectively, much higher than those of 54 and 72% over a commercial VWT catalyst, indicating great promise for industrial application.

Microbiology rapid on-site evaluation: a better method for Mucoid Pseudomonas Aeruginosa diagnosis in bronchiectasic patients

OBJECTIVE

The aim of this study is to find an accurate and fast method to diagnose the pathogen of bronchiectasis.

PATIENTS AND METHODS

Ten bronchiectasic patients diagnosed with Mucoid Pseudomonas Aeruginosa (MPA) in the past two years were analyzed. Accuracy and time were compared between microbiology rapid on-site evaluation (M-ROSE) and sputum bacterial culture.

RESULTS

The accuracy rate of M-ROSE in the patients is 100% consistent with bacterial culture results. The average time of M-ROSE is about 4.3 min, which is over 1000 times shorter than that of sputum bacterial culture.

CONCLUSIONS

M-ROSE may be a better method for etiological diagnosis of MPA.

[Contrastive analysis about the postoperative clinical characteristics of elderly patients with colorectal cancer in different age groups]

Objective: To explore the postoperative clinical characteristics of elderly patients with colorectal cancer at different ages. Methods: Retrospective analysis was performed on the clinical data of 720 elderly patients with Colorectal Cancer in Beijing Hospitals from January 2012 to December 2019. There were 411 males and 309 females with a median age of 74 years. We divided the patients into young-old, old-old, oldest-old colorectal cancer patient groups and used chi-square comparative analysis of different groups of patients with clinical disease characteristics. Results: The oldest-old colorectal cancer patients tended to have normal body mass index (BMI), and the site of the disease shifted to the right. The incidence of concomitant diseases such as heart disease and hypertension increases gradually with age, and the incidence of diabetes is highest in old-old colorectal cancer patients. The proportion of open surgery was higher in the oldest-old group, but the operation time was shorter than the other two groups. In addition, the incidence of postoperative complications in elderly patients with colorectal cancer gradually increases with age, especially cardiac complications and other complications such as pneumonia, deep venous thrombosis of lower limbs, urinary retention, urinary tract infection, renal failure, cerebral hemorrhage, cerebral infarction, and so on. Conclusions: The BMI of the oldest-old patients tended to be normal, and the site of the disease shifted to the right. The incidence of heart disease, hypertension, and other concomitant diseases and postoperative complications in elderly patients with colorectal cancer gradually increase with age. Thus, the choice of treatment should be more individualized for elderly patients with colorectal cancer, and more attention should be paid to perioperative management.

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.