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.

[Comparison of the efficacy of robot assisted and thoracoscopic assisted thoracic surgery in non-small cell lung cancer].

Objective: To compare the safety and short-term efficacy of robotic-assisted thoracic surgery(RATS) and video-assisted thoracoscopic surgery(VATS) in patients with non-small cell lung cancer (NSCLC). Methods: A retrospective analysis of the clinical data of 2 058 NSCLC patients who underwent RATS and VATS from January 2021 to December 2022 in Xiangya Hospital of Central South University was conducted, including 1 006 males and 1 052 females, with the age of (57.3±9.9) years. According to the surgical approach, the patients were divided into RATS group (n=1 190) and VATS group (n=868). The nearest neighbor matching method was used to perform 1∶1 propensity score matching (PSM). A comparison was made about the intraoperative conditions and postoperative complication rates between the RATS and VATS groups before and after PSM. Furthermore, after PSM, a stratified analysis was conducted based on surgical approach, separately comparing the intraoperative conditions and postoperative complication rates between the VATS and RATS groups among patients who underwent lobectomy and segmentectomy, respectively. Results: After PSM, a total of 1 692 patients were included, with 846 patients in both the VATS and RATS groups. After stratification based on surgical approach, there were 503 patients in the RATS group and 548 patients in the VATS group for lobectomy, and 338 patients in the RATS group and 298 patients in the VATS group for segmentectomy. Before PSM, statistically significant differences were observed between the RATS and VATS groups in terms of intraoperative conversion to open thoracotomy, number of lymph node dissection/sampling stations, extubation time, total length of hospital stay, and total hospitalization costs (all P<0.001). After PSM, compared with the VATS group, the RATS group had a lower intraoperative conversion rate to open surgery [1.2% (10/846) vs 5.1% (43/846)], less intraoperative blood loss [(73.6±77.4) ml vs (112.6±239.3) ml], a greater number of sampled/dissected lymph node stations [(4.8±2.0) vs (3.7±1.8)], a shorter duration of drainage tube placement [(3.6±2.7) d vs (4.1±2.5) d], and a higher postoperative drainage volume [(273.9±183.0) ml vs (256.5±168.7) ml] (all P<0.001). There was no statistically significant difference in the incidence of postoperative complications between the two groups (P=0.108). The results of the surgical stratification analysis showed statistically significant differences between the two groups in terms of intraoperative blood loss, number of lymph node dissection/sampling stations, extubation time, and total hospitalization costs for both lobectomy and segmentectomy surgeries (all P<0.001). In lobectomy surgeries, the RATS group had a lower rate of intraoperative conversion to open thoracotomy than that of VATS group [1.6% (8/503) vs 7.7% (42/548), P<0.001]. In segmentectomy surgeries, the RATS group had more postoperative drainage volume than that of VATS group [(249.8±151.5) ml vs (218.7±132.9) ml, P=0.023]. There was no statistically significant difference in the incidence of surgical complications between the two groups for both lobectomy and segmentectomy surgeries (both P>0.05). Conclusion: In the surgical management of NSCLC, RATS offers more advantages over VATS in reducing conversion rates to open surgery, minimizing perioperative adverse events, and facilitating faster patient recovery postoperatively.

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.

[Safety and feasibility of robotic-assisted thoracoscopic day surgery for pulmonary nodules: a retrospective analysis based on propensity score matching].

Objective: To evaluate the safety and feasibility of robotic-assisted thoracoscopic day surgery for pulmonary nodules. Methods: Clinical data of 523 patients with pulmonary nodule underwent robotic-assisted thoracoscopic surgery in the Department of Thoracic Surgery, Xiangya Hospital, Central South University from January 2021 to June 2022 were retrospectively analyzed, which including 223 males and 300 females, aged from 19 to 72 (54.0±11.7) years. Those patients were divided into the day surgery group (DSG) and inpatient surgery group (ISG) according to perioperative management methods. Propensity score matching (PSM) (1∶2) was performed according to the general baseline information, T stage of the tumor, surgery approach, and tumor position, and a total of 178 patients were finally included. Clinical outcomes of DSG were observed. The differences in incidence of postoperative complications, treatment-related costs and resource consumption between DSG and ISG were compared. Subgroup analysis was performed according to surgery method to evaluate the difference between DSG and ISG in lobectomy and sublobectomy. Results: In 81 cases DSG, eight patients were transferred to thoracic surgery ward, and the day surgery discharge rate was 90% (73/81). There was no statistically significant difference in incidence of postoperative complications between DSG and ISG (P=0.612). The length of stay after surgery, period of chest draining, average hospital cost, and drug cost of DSG were statistically significant lower than ISG, ((2.19±0.84) vs (4.74±1.81) days, (1.70±0.65) vs (3.45±1.85) days, (6.64±0.74) vs (8.29±0.97)×104 CNY, (0.35±0.07) vs (0.69±0.18)×104 CNY), respectively(all P<0.05). The drainage volume and VAS score at discharge in DSG and ISG group were(220.47±120.02) ml and(242.21±129.96) ml, 1.68±0.79 and 1.64±0.91, respectively, with no statistically significant difference (P>0.05). In subgroup analysis, there was no statistically significant difference in incidence of postoperative complications, drainage volume after surgery and VAS score at discharge between DSG and ISG both for lobectomy and sublobectomy patients. And the results of the length of stay after surgery, period of chest draining, and drug cost in DSG were also significantly lower than ISG (P<0.05). Conclusions: Robotic-assisted thoracoscopic day surgery for pulmonary nodule is safe and feasible, with the advantage of short length of stay after surgery, short period of chest draining, less average hospital cost and drug cost. There is no difference in incidence of postoperative complications between DSG and ISG.

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.

Notch signaling is involved in regulation of LPS-induced macrophage apoptosis through JNK/NF-kB signaling pathway.

Notch signaling plays a critical role in the development and function of macrophages. The aim of the present study was to investigate the relationship between Notch signaling pathway and macrophage apoptosis after LPS stimulation. In RAW 264.7 cells, the mRNA expression of Jagged1, Hes1, Hes 5 and GM-CSF, and protein expression of NICD1 and GM-CSF were increased after LPS stimulation. Inhibition of Notch signaling by γ-secretase inhibitor DAPT and the suppression of Notch1 expression using siRNA both significantly prevented LPS induced activation of JNK and NF-kB, and simultaneously the expression of GM-CSF was also down regulated significantly. JNK inhibitor SP600125 was used to block the phosphorylation of JNK signaling, Western blot results showed that the activation of NF-kB was blocked and expression of GM-CSF was down-regulated. Finally, flow cytometry analyses showed that the Notch signaling was involved in the regulation of macrophage apoptosis after LPS stimulation. Our study showed that the Notch signaling pathway was activated and involved in the regulation of macrophage apoptosis after LPS stimulation through JNK/ NF-kB signaling regulated GM-CSF expression.

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.

Isothermal Fourier transform infrared microspectrosopic studies on the stability kinetics of solid-state intramolecular cyclization of aspartame sweetener.

A novel Fourier transform infrared (FT-IR) microspectrophotometer equipped with differential scanning calorimetry (DSC) was used to investigate the kinetics of intramolecular cyclization of aspartame (APM) sweetener in the solid state under isothermal conditions. The thermal-dependent changes in the peak intensity of IR spectra at 1543, 1283, and 1259 cm(-1) were examined to explore the reaction. The results support that the intramolecular cyclization process in APM proceeded in three steps: the methoxyl group of ester was first thermolyzed to release methanol, then an acyl cation was attacked by the lone pair of electrons available on nitrogen by an S(N)1 pathway, and finally ring-closure occurred. The intramolecular cyclization of APM determined by this microscopic FT-IR/DSC system was found to follow zero-order kinetics after a brief induction period. The bond cleavage energy (259.38 kJ/mol) of thermolysis for the leaving group of -OCH(3), the bond conversion energy (328.88 kJ/mol) for the amide II NH band to DKP NH band, and the CN bond formation energy (326.93 kJ/mol) of cyclization for the DKP in the APM molecule were also calculated from the Arrhenius equation. The total activation energy of the DKP formation via intramolecular cyclization was 261.33 kJ/mol, calculated by the above summation of the bond energy of cleavage, conversion, and formation, which was near to the value determined by the DSC or TGA method. This indicates that the microscopic FT-IR/DSC system is useful as a potential tool not only to investigate the degradation mechanism of drugs in the solid state but also to directly predict the bond energy of the reaction.

Study of correlation of Se content in human hair and internal organs by INAA.

The correlations of essential element Se between human hair and kidney-cortex, liver, and lung from the same subjects were investigated by instrumental neutron activation analysis, using the reaction 76Se (n, gamma) 77mSe, for 24 Chinese autopsies. The concentration of Se is higher in kidney-cortex (2.04-5.36 mg/kg) than in liver (0.73-2.29), lung (0.50-1.85), and hair (0.37-1.43). It is important to know that there are significant relationships of Se concentration between hair and the other three internal organs. The correlation coefficient by linear regression analysis are 0.639, 0.570, and 0.635 for liver, lung, and kidney-cortex, respectively; and the P values are all less than 0.01 for the three tissues.

Preliminary study of the distribution of the toxic elements As, Cd, and Hg in human hair and tissues by RNAA.

In order to study the relationships between trace element concentrations of hair and internal body burdens, a radiochemical NAA technique has been used for determination of the elements As, Cd, and Hg in autopsy samples of liver, kidney-cortex, lung, and hair from 24 male persons who died by accident. High significant positive correlations were observed between the As concentration in hair and in kidney-cortex, and between Cd and Zn concentrations in kidney-cortex. The contents of Cd, both for lung and kidney-cortex, were related to the smoking habits of the subjects.

[Establishment of a mammary cancer cell line Ca 761-86 and its biologic characteristics in inbred 615 mice].

A cell line designated as Ca761-86 has been established from the solid mouse mammary cancer (Ca761) by suspension culture. It has been passaged for more than 200 generations. Moderate round cells were predominant and most of them were mononuclear. Some characteristics of malignant cells and A-type viral-like particles were observed by electron microscopy. The results of cytochemical studies (DNA, RNA, SDH, 5'AMPase, ACP etc) were comparable to the ultramicroscopic results. It multiplied approximately 27.4 fold on Day 5 with mitotic index reaching 1.8% on Day 3. This cell line was a hyperdiploid with karyotype of 45 or 43, -2X, tri12, tri17, +M1-5. Cell agglutination was observed when treated with ConA (greater than or equal to 7 micrograms/ml). Spontaneous agglutination might also take place without adding any ConA. After 5 x 10(6) cells of Ca761-86 suspension were transplanted into the normal inbred 615 mice by different ways (subcutaneous, intrafoot pad or intraperitoneal), the transplantability rate reached 100%. Spontaneous remission was never observed and its metastatic ability reserved. PPLO were not detected. Ca761-86 may be of value for practical purposes.

Clinical controlled comparison between lobectomy and segmental resection for patients over 70 years of age with clinical stage I non-small cell lung cancer.

AIMS: The standard surgical procedure for elderly (≥ 70 years) patients with clinical stage I non-small cell lung cancer (NSCLC) was investigated. METHODS: A non-randomized prospective controlled study was conducted to compare lobectomy with segmental resection for the treatment of elderly clinical stage I lung cancer patients under different pulmonary function. Perioperative indicators including time and volume of thoracic drainage, incidence of postoperative complications, locoregional recurrence rates, and 1, 3, and 5-year survival rates were analyzed. RESULTS: A total of 184 patients were included in the study. Patients were classified into two groups according to pulmonary function: group 1 included 64 patients who had poor pulmonary function, with a forced expiratory volume in 1 s (FEV(1)) of less than 1.5 L, whereas group 2 consisted of 120 patients with an FEV(1) ≥ 1.5 L. The patients in group 1 had a longer postoperative mechanical ventilation time and a higher incidence rate of respiratory associated complications than those in group 2 (21.9 vs. 8.35%, p = 0.009). The local recurrence and long-term survival rates were not significantly different between lobectomy and segmental resection. Among the patients who underwent segmental resection, those who had regional lymph node dissection showed a higher 3-year and 5-year survival rate than those undergoing selected lymph node resection (77.8 vs. 51.7%, p = 0.042; 55.6 vs. 27.6%, p = 0.034), but this was not significant in lobectomy. CONCLUSIONS: Segmental resection combined with regional lymph node resection could be the best choice for elderly clinical stage I NSCLC patients with FEV(1) < 1.5 L.

Simultaneous formation and detection of the reaction product of solid-state aspartame sweetener by FT-IR/DSC microscopic system.

The solid-state stability of aspartame hemihydrate (APM) sweetener during thermal treatment is important information for the food industry. The present study uses the novel technique of Fourier transform infrared microspectroscopy equipped with differential scanning calorimetry (FT-IR/DSC microscopic system) to accelerate and determine simultaneously the thermal-dependent impurity formation of solid-state APM. The results indicate a dramatic change in IR spectra from 50, 110 or 153 degrees C, which was respectively attributed to the onset temperature of water evaporation, dehydration and cyclization processes. It is suggested that the processes of dehydration and intramolecular cyclization occurred in the solid-state APM during the heating process. As an impurity, 3-carboxymethyl-6-benzyl-2,5-diketopiperazine (DKP) degraded from solid state APM via intramolecular cyclization and liberation of methanol. This was evidenced by this novel FT-IR/DSC microscopic system in a one-step procedure.