Search

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.

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.

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.

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 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.

Objective: To evaluate the meaning of arthrography with cone-beam CT（CBCT） imaging in the diagnosis of temporomandibular disorders(TMD). Methods: Four hundred and forty-eight cases of temporomandibular upper joint cavity arthrography with CBCT imaging were retrospectively analyzed. The distribution of disc displacement with reduction or without reduction, disc perforation, enlargement or tearing of joint capsule were analyzed. The characteristics of arthrography with CBCT imaging were also described. Results: There were 384 female and 64 male among the 448 cases of TMD with CBCT arthrographic images. The median age was 31.5 years， range from 14 to 81 years old. As about the age distribution, there were 63 cases in the group of ≤20 years old, 150 cases in the group of >20 and ≤30 years old, 86 cases in the group of >30 and ≤40 years old, 59 cases in the group of >40 and ≤50 years old, 58 cases in the group of>50 and ≤60 years old, and 32 cases in the group of >60 years old. There were 356 cases with disc displacement, in which there were 328 cases of disc displacement without reduction, and 28 cases of disc displacement with reduction. There were 152 cases with disc perforation, and 12 cases with articular capsule tearing or laxation. Conclusions: Arthrography with CBCT imaging was a meaningful approach to diagnose the TMD with structure disorders.

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., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Objective: The aim of this study was to investigate the expression level of micro-ribonucleic acid-1207-5p (miR-1207-5p) in steroid-induced necrosis of femoral head (SNFH) and its correlation with SNFH. Meanwhile, we also aimed to analyze the relationship between miR-1207-5p expression and vascular endothelial growth factor (VEGF) in the femoral head., Patients and Methods: From May 2016 to December 2017, 60 patients aged (55.4±8.7) were selected in our hospital. All patients were diagnosed and confirmed as SNFH. Total RNA was extracted from the necrotic femoral head tissues and peripheral blood. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used to detect the expression level of miR-1207-5p in tissues. At the same time, immunohistochemistry and Western blotting were adopted to detect VEGF expression in the bone tissue of patients with high or low expression of miR-1207-5p. 7 patients with femoral neck fracture aged (45.6±4.51) were enrolled in the control group. In the animal experiment, the rat SNFH model was established by intraperitoneal injection of lipopolysaccharide and methylprednisolone. Subsequently, the expression levels of miR-1207-5p and VEGF in necrotic femoral tissues were detected. Meanwhile, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was applied to detect cell apoptosis in bone lacunae of miR-1207-5p high expression group and miR-1207-5p low expression group, respectively., Results: The expression level of miR-1207-5p in the necrotic bone tissue of the SNFH group was significantly higher than that of the control group. The expression level of miR-1207-5p was inversely proportional to Harris Hip score (p<0.05). A higher expression of miR-1207-5p indicated a lower expression level of VEGF (p<0.05). The animal experimental results revealed that miR-1207-5p expression in the necrotic femoral head tissue of SNFH group was significantly higher than that of the control group. Furthermore, the number of apoptotic cells in bone lacunae was remarkably higher in miR-1207-5p high expression group (p<0.05)., Conclusions: MiR-1207-5p is significantly up-regulated in necrotic femoral head tissue and serum of SNFH patients. Meanwhile, its expression level is inversely proportional to Harris Hip score of patients. The possible underlying mechanism may be related to the inhibitory effect of miR-1207-5p on VEGF.

Core-shell type 'nanoghosts' were synthesized with a drug-loaded biodegradable PLGA core and a monocyte cell membrane-derived shell. The nanoghosts were monodisperse with an average size <200 nm, and showed good serum stability for 120 h. Doxorubicin-loaded nanoghosts showed greater cellular uptake and cytotoxicity compared to non-coated nanoparticle controls in metastatic MCF-7 breast cancer cell lines.

Consistent cytogenetic abnormalities have been described in many pediatric solid tumors, including Ewing's sarcoma, Wilms' tumor, and neuroblastoma. Similar analysis of pediatric central nervous system (CNS) tumors has been hampered by technical problems. We report chromosome results from 39 pediatric CNS tumors. Abnormalities of chromosome 17 were noted in 3 of 11 primitive neuroectodermal tumors (including i(17q) in 2 tumors), confirming data observed by other investigators. Cells from 2 of 11 primitive neuroectodermal tumors (PNET) exhibited loss or structural abnormalities involving chromosome 11. Loss or distal deletion of chromosome 7q was noted in cells from two PNETs. Because other investigators have shown loss of heterozygosity on 17p in about one-third of PNET, we propose that chromosome regions 7q and 11 are areas worthy of further study in pediatric PNET. Numerical abnormalities were noted in 6 of 21 astrocytomas. Hyperdiploidy was demonstrated in 1 of 4 pilocytic astrocytomas and pseudopolyploidy was demonstrated in 4 of 13 anaplastic astrocytomas. Structural chromosome abnormalities (translocations, deletions) were noted in 4 of 13 anaplastic astrocytomas. Complex structural anomalies were observed in one craniopharyngioma. A rhabdoid tumor of the brain exhibited multiple complex structural rearrangements but did not exhibit the monosomy 22 observed in some rhabdoid tumors. Hypodiploidy and loss of chromosome 22 were noted in a clinically aggressive meningioma, corroborating observations by other investigators.

The malignant rhabdoid tumor is a rare, poorly understood tumor which occurs primarily in children. The kidney is a frequent primary site of origin, but the tumor has arisen in other mesodermally derived tissues as well. Controversy exists regarding the embryonic origin of the rhabdoid tumor and recent histopathologic studies suggest that it may be of neuroepithelial origin. Our immunohistochemical and electron micrographic studies support this theory. No consistent chromosome abnormalities have been reported in this tumor and no cell lines are available for study. We have established and characterized the first rhabdoid tumor cell line. It possesses a specific chromosomal abnormality, 46,XY,t(11;22)(p15.5;q11.23). The translocation may provide an important clue to the pathogenesis of the tumor as well as an opportunity for further study of the involved chromosome regions.

A number of protooncogenes have been implicated in human tumorigenesis. The ABL oncogene is consistently rearranged and activated as a consequence of the translocation t(9;22) that gives rise to the Philadelphia chromosome in chronic myeloid leukemia and in some cases of acute lymphoblastic leukemia. Here we describe rearrangement of ABL in a different type of malignancy. The glioblastoma cell line A172 lacks germline alleles of ABL. A recombination event, presumably followed by a duplication, has created two ABL alleles in which exon 11 is joined to chromosome 16 sequences. Although the main body of ABL exons was still present, two considerably shortened ABL mRNAs of 3.8 and 2.8 kilobases were detected; the 3.8-kilobase mRNA hybridized exclusively to an exon IB probe. Neither mRNA hybridized to an ABL probe encompassing part of the tyrosine kinase domain. Thus, the cell line A172 is able to survive in the absence of a functional ABL gene product, indicating that the role of ABL is unlikely to be "housekeeping."

The frequencies of chromosomal aberrations and sister-chromatid exchanges (SCEs) in the peripheral blood lymphocytes of 360 persons, 180 workers in a petrochemical corporation and 180 appropriate controls, were studied. A significant increase in chromosomal aberrations and SCEs, compared to the control group, was observed in two sewage-treatment workshop workers; however, there were no significant differences between petrochemical workers from four workshops and a control group.

Three minority ethnic groups from China (Mongolians, Koreans, Zhuang) were examined with respect to the genetic markers GLO, GPT, ACP, ESD, 6-PGD, PGM1 subtypes, C3, and TF. Significant variations were noted for the gene frequencies of GLO, GPT, ESD, sub PGM1 between Zhuang and Mongolians; for GPT, ACP, ESD, sub PGM1 between Zhuang and Koreans; and for GLO between Mongolians and Koreans.

Four different populations of China were studied regarding aldehyde dehydrogenase isozyme variation and incidence of alcohol sensitivity. While Korean and Mongolian minorities in the north showed an isozyme I deficiency with a frequency of about 25 and 30%, 45-50% of Zhuang and Han were deficient, respectively. Adverse reactions after alcohol drinking were mainly reported by those subjects who showed the lack of aldehyde dehydrogenase isozyme I.

A modified technique is described for obtaining extended metaphase chromosomes (600 bands) from direct preparations of chorionic villi, allowing rapid detection of subtle structural aberrations with minimal risk of maternal-cell contamination. Analysis of multiple individually processed villus fragments may be helpful in recognizing mosaicism confined to chorionic villi.

Among different blood-group systems investigated here, the distribution of the ABO system varies most of all, followed by MNSs and P. Although there are differences in ABH secretion in the different populations, no striking regularity has been found. No significant difference has been found in the distribution of the blood-group systems Rhesus, Diego, Duffy, Kell and Kidd in these Chinese populations: the Rh (-) rate is less than 1%, the frequency of Dia is about 0.04, the frequency of Fya is rather high, the frequency of K extremely low and Jka is about 0.4. In the three nationalities under study, Mongolians are characterized by a high frequency of IB, M higher than 0.5 and a relatively high frequency of P1. Koreans are characterized by a high frequency of IA, slightly more M than N and rather high CDE in the Rh system. The peculiarities of the Zhuangs are a rather high frequency of IO and M and the lowest frequency of P1.

Three minority ethnic groups from China, Mongolian, Koreans, and Zhuangs were studied for the genetic markers AK, ADA, Hp, and Pi. AK was monomorphic in Koreans and Zhuangs. Significant differences were observed in the Hp system between Mongolians and Zhuangs.