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.

Hemoglobin variability in patients receiving EPO and roxadustat during maintenance hemodialysis: a self-control study

OBJECTIVE

The aim of this study was to investigate the hemoglobin variability in patients undergoing maintenance hemodialysis during the application of erythropoietin (EPO) and roxadustat.

PATIENTS AND METHODS

For this retrospective study, we analyzed the clinical records of 80 patients with renal anemia on maintenance hemodialysis (MHD) admitted to our hospital between January 2017 and December 2022. We adopted a self-control design comparing the hemoglobin variability of the values before and after roxadustat administration in each patient. The patients received EPO from January 2017 to December 2019 and roxadustat from January 2020 to December 2022. We compared the levels of serum ferritin, transferrin saturation, and hemoglobin and calculated the hemoglobin variabilities by comparing values before and after roxadustat treatments.

RESULTS

We found higher transferrin saturation levels at different time points after the roxadustat treatments (p<0.01); meanwhile, the serum ferritin and hemoglobin levels were significantly higher after the roxadustat treatment (p<0.001). During the treatments with EPO and roxadustat, the transferrin saturation, serum ferritin, and hemoglobin levels differed significantly at different time points for each patient (p<0.05). After roxadustat administration, the hemoglobin levels were significantly higher than after EPO administration (p<0.001) and changed more rapidly after roxadustat administration than after EPO administration (p<0.05). The hemoglobin variability after roxadustat administration was significantly lower than that after EPO administration (p<0.05).

CONCLUSIONS

Treatment with roxadustat led to higher hemoglobin levels and less hemoglobin variability than the treatment with EPO, with high transferrin saturation and higher ferritin levels in patients with renal anemia on MHD.

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.

Anaemia prevalence and risk factors among children aged 6 to 23 months in rural China

INTRODUCTION

Anaemia is a global public health problem among children. However, few studies have examined anaemia prevalence and risk factors among Chinese children of different ages, particularly in poor rural areas. This study investigated these two aspects among children aged 6 to 23 months in poor rural areas of China.

METHODS

This cross-sectional study included 1132 children aged 6 to 23 months in three prefectures of the Qinba Mountains area. A finger prick blood test for haemoglobin and anaemia was conducted, along with household surveys of socio-demographic characteristics, illness characteristics, and feeding practices. Multiple linear and logistic regression analyses were used to determine predictors of anaemia.

RESULTS

Overall, 42.6% of children in the study displayed anaemia. Children aged 6 to 11 months had the highest anaemia prevalence (53.6%). Anaemia risk factors differed among age-groups and throughout the overall sample. Bivariate and multivariable regression results showed that continued breastfeeding, any history of formula feeding, and consumption of iron-rich or iron-fortified foods were prominent risk factors for anaemia. However, continued breastfeeding and any history of formula feeding had the greatest impact across age-groups (both P<0.05).

CONCLUSION

Anaemia remains a severe public health problem among children aged 6 to 23 months in rural China. Healthy feeding practices, nutritional health knowledge, and nutrition improvement projects are needed to reduce the burden of anaemia among children in rural areas of China.

Development of a novel combined nomogram integrating deep-learning-assisted CT texture and clinical-radiological features to predict the invasiveness of clinical stage IA part-solid lung adenocarcinoma: a multicentre study

AIM

To develop a novel combined nomogram based on deep-learning-assisted computed tomography (CT) texture (DL-TA) and clinical-radiological features for the preoperative prediction of invasiveness in patients with clinical stage IA lung adenocarcinoma manifesting as part-solid nodules (PSNs).

MATERIALS AND METHODS

This study was conducted from January 2015 to October 2021 at three centres: 355 patients with 355 PSN lung adenocarcinomas who underwent surgical resection were included and classified into the training (n=222) and validation (n=133) cohorts. PSN segmentation on CT images was performed automatically with a commercial deep-learning algorithm, and CT texture features were extracted. The least absolute shrinkage and selection operator was used for feature selection and transformed into a DL-TA score. The combined nomogram that incorporated the DL-TA score and identified clinical-radiological features was developed for the prediction of pathological invasiveness of the PSNs and validated in terms of discrimination and calibration.

RESULTS

The present study generated a combined nomogram for predicting the invasiveness of PSNs that included age, consolidation-to-tumour ratio, smoking status, and DL-TA score, with a C-index of 0.851 (95% confidence interval: 0.826-0.877) for the training cohort and 0.854 (95% confidence interval: 0.817-0.891) for the validation cohort, indicating good discrimination. Furthermore, the model had a Brier score of 0.153 for the training cohort and 0.135 for the validation cohort, indicating good calibration.

CONCLUSION

The developed combined nomogram consisting of the DL-TA score and clinical-radiological features and has the potential to predict the individual risk for the invasiveness of stage IA PSN lung adenocarcinomas.

[Construction of a dual fluorescent reporter system for tracing horizontal transfer of mcr-1-carrying plasmid]

The green fluorescent reporter gene was inserted into the gene interval of polymyxin resistant mcr-1-carrying plasmid (pSH13G841) by homologous recombination of suicide plasmid. At the same time, E. coli J53 with red fluorescent reporter gene was constructed. Using the ability of spontaneous conjugation of drug resistant plasmid (pSH13G841), pSH13G841-GFP plasmid was transferred into J53 RFP bacteria to construct a double fluorescent labeled donor bacterium. The two light-emitting systems could stably and spontaneously express fluorescence without mutual interference. The dual fluorescence report system constructed can be used for visual tracing horizontal transfer of mcr-1-carrying plasmid, the subsequent model can study the colonization, transfer and prognosis of drug-resistant bacteria/drug-resistant genes mcr-1 by using mouse in vivo imaging technology.

[Progress of researches on the role and mechanisms of non - coding RNA in Angiostrongylus cantonensis infection]

Angiostrongylus cantonensis is a food-borne zoonotic parasite, and human infection may cause eosinophilic meningitis. Non-coding RNAs (ncRNAs) may regulate physiological and pathological processes at multiple biological levels; however, there are few studies pertaining to the regulatory role of ncRNAs in A. cantonensis infection. Based on publications retrieved from PubMed, Wanfang Data and CNKI, the regulatory role of ncRNAs in A. cantonensis infections mainly includes immune responses, cell apoptosis and signaling transduction, and ncRNAs may serve as biomarkers for diagnosis of angiostrongyliasis. This review summarizes the main roles of ncRNAs in A. cantonensis infections and the underlying mechanisms, so as to provide insights into diagnosis and treatment of angiostrongyliasis.

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.

[Metal artifact reduction and clinical verification in oral and maxillofacial region based on deep learning]

Objective: To construct a kind of neural network for eliminating the metal artifacts in CT images by training the generative adversarial networks (GAN) model, so as to provide reference for clinical practice. Methods: The CT data of patients treated in the Department of Radiology, West China Hospital of Stomatology, Sichuan University from January 2017 to June 2022 were collected. A total of 1 000 cases of artifact-free CT data and 620 cases of metal artifact CT data were obtained, including 5 types of metal restorative materials, namely, fillings, crowns, titanium plates and screws, orthodontic brackets and metal foreign bodies. Four hundred metal artifact CT data and 1 000 artifact-free CT data were utilized for simulation synthesis, and 1 000 pairs of simulated artifacts and metal images and simulated metal images (200 pairs of each type) were constructed. Under the condition that the data of the five metal artifacts were equal, the entire data set was randomly (computer random) divided into a training set (800 pairs) and a test set (200 pairs). The former was used to train the GAN model, and the latter was used to evaluate the performance of the GAN model. The test set was evaluated quantitatively and the quantitative indexes were root-mean-square error (RMSE) and structural similarity index measure (SSIM). The trained GAN model was employed to eliminate the metal artifacts from the CT data of the remaining 220 clinical cases of metal artifact CT data, and the elimination results were evaluated by two senior attending doctors using the modified LiKert scale. Results: The RMSE values for artifact elimination of fillings, crowns, titanium plates and screws, orthodontic brackets and metal foreign bodies in test set were 0.018±0.004, 0.023±0.007, 0.015±0.003, 0.019±0.004, 0.024±0.008, respectively (F=1.29, P=0.274). The SSIM values were 0.963±0.023, 0.961±0.023, 0.965±0.013, 0.958±0.022, 0.957±0.026, respectively (F=2.22, P=0.069). The intra-group correlation coefficient of 2 evaluators was 0.972. For 220 clinical cases, the overall score of the modified LiKert scale was (3.73±1.13), indicating a satisfactory performance. The scores of modified LiKert scale for fillings, crowns, titanium plates and screws, orthodontic brackets and metal foreign bodies were (3.68±1.13), (3.67±1.16), (3.97±1.03), (3.83±1.14), (3.33±1.12), respectively (F=1.44, P=0.145). Conclusions: The metal artifact reduction GAN model constructed in this study can effectively remove the interference of metal artifacts and improve the image quality.

[Advances in clinical characteristics of talaromycosis combined with other opportunistic infections]

Talaromycosis (TSM) is an opportunistic deep mycosis prevalent in southeast Asia and southern China, affecting HIV-positive, anti-interferon-gamma autoantibody-positive and other immunodeficiency hosts. These hosts are often co-infected with mycobacterium tuberculosis, non-tuberculosis mycobacteria, bacteria, fungi, viruses and other opportunistic infections. The clinical characteristics and the pathogenic spectrum of TSM with opportunistic infections vary with different immune states. The rates of misdiagnosis, missed diagnosis and mortality are high. This review summarized the clinical characteristics of TSM with opportunistic infections in order to improve the level of clinical diagnosis and treatment.

METTL21C mediates lysine trimethylation of IGF2BP1 to regulate chicken myoblast proliferation

1. Methyltransferase-like 21C (METTL21C) and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) play important roles in the proliferation of chicken myoblasts. However, it remains unclear whether there is protein-protein interaction between METTL21C and IGF2BP1 to regulate proliferation of chicken myoblasts.2. In this study, the Igf2bp1 gene was amplified from cDNA of liver tissue of Lueyang black-bone chicken to construct the overexpression vector HA-Igf2bp1. The HA-Igf2bp1 and Flag-Mettl21c vectors were individually transfected and co-transfected into HEK293T, respectively. Co-immunoprecipitation (Co-IP) assay indicated a protein-protein interaction between METTL21C and IGF2BP1.3. Using the Western blotting and LC-MS/MS, it was found that METTL21C could mediate the lysine methylation modification of IGF2BP1. Furthermore, the His-tagged overexpression vector HA-Igf2bp1-His was constructed, transfected and co-transfected with Flag-Mettl21c into HEK293T. His-tagged IGF2BP1 was purified by nickel ion affinity chromatography. Western blotting revealed that IGF2BP1 was successfully purified, and the trimethylation modification level of co-transfection group was significantly elevated compared with the single-transfection Igf2bp1 group.4. Mettl21c and Igf2bp1 overexpression vectors were transfected and co-transfected into primary chicken myoblasts, respectively. The results of 5-ethynyl-2'-deoxyuridine assay and the expression level of Pax7 and MyoD indicated that overexpression of Igf2bp1 alone inhibited the chicken myoblast proliferation, whereas co-expression of Mettl21c and Igf2bp1 eliminated the inhibitory effects of Igf2bp1, thereby favouring cell proliferation and differentiation.5. The results, for the first time, revealed that METTL21C mediated the lysine trimethylation modification of IGF2BP1 to regulate the proliferation of chicken myoblasts, which provided a new insight into in-depth analysis of the molecular mechanism of METTL21C methylation involved in regulating the growth and development of skeletal muscle in Lueyang black-bone chicken.

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.

Improving cybersecurity incidents reporting in Nigeria: micro and small enterprises perspectives

Leveraging on the provisions of the internet enhances the productivity of Micro and Small Enterprises (MSEs), increases industrial growth and their contributions to national prosperity. Every cyber-attack against their businesses should be reported to the requisite incident response body through the appropriate channels for quick recovery from attack. This research examines how the MSEs in Nigeria report cybersecurity incidents. This study surveyed 100 MSEs. The outcome of the research shows that 72% of the MSEs is unaware of the channel of reporting cyber incidents and does not report cyber incidents. Participants totaling 90% believe that the Sectoral Computer Security Incident Response Team (CSIRT) could improve on reporting of cybersecurity incidents through sensitisation. Amongst others, we recommended the Sectoral CSIRTs were to develop an Incident Report and Response Plan (IRRP) for managing cybersecurity incidents in MSEs.

[Virtual reconstruction and clinical verification of maxillary defect based on deep learning]

Objective: To construct a virtual reconstruction method including midspan maxillary defects and provide clinical reference by training a generative adversarial network (GAN) model. Methods: The CT data of middle-aged Han patients with oral diseases who visited the Department of Radiology, West China Hospital of Stomatology, Sichuan University from June 2015 to June 2022 were collected, where the CT data of 100 healthy maxilla and 15 maxillary defects (5 simple unilateral defects, 5 unilateral defects involving zygomatic bone, 5 midspan defects) were selected. Mimics was used to create spherical phantom and simulate bone defects around the healthy maxillas, including simple unilateral defects, unilateral defects involving zygomatic bone and midspan defects. The original image was set as the correct reference for the reconstruction: artificial defects paired with the correct reference were divided into training set (n=70), validation set (n=20) and test set (n=10), where the first two were used to train the GAN model, and the test set was used to evaluate the GAN performance. Data from 15 clinical defects were imported into the trained GAN model for reconstruction, with mirroring and GAN-based virtual reconstruction for unilateral clinical defects, and only the latter method was adopted for midspan defects. The reconstruction results were divided into mirror reconstruction group (n=10), unilateral defect GAN reconstruction group (n=10) and midspan defect GAN reconstruction group (n=5). The test set, mirror reconstruction group, and unilateral defect GAN reconstruction group were quantitatively evaluated, whose quantitative indicators were Dice similarity coefficient (DSC) and 95% Hausdorff distance (HD95), and the group results were subjected to one-way ANOVA and Tukey test. The test set, mirror reconstruction group, unilateral defect GAN reconstruction group and midspan defect GAN reconstruction group were qualitatively scored, and Kruskal-Wallis test and Bonferroni correction were used for the total score of each group. Results: The total differences in the test set, mirror reconstruction group, unilateral defect GAN reconstruction group DCS (0.891±0.049, 0.721±0.047, 0.778±0.057, respectively) and HD95 [(3.58±1.51), (5.19±1.38), (4.51±1.10) mm, respectively] were statistically significant (F=28.08, P<0.001; F=3.62, P=0.041); among them, the test set DSC was significantly larger than the mirror reconstruction group (P<0.05), and the test set HD95 was significantly less than the mirror reconstruction group (P<0.05). Overall difference in qualitative total scores [8 (1), 6 (2), 6 (2), and 4 (2) points, respectively] in the test set, mirror reconstruction group, unilateral defect GAN reconstruction group, and midspan defect GAN reconstruction group were statistical significance (H=18.13, P<0.001); pairwise comparison showed that the total score of the test set was significantly higher than that of the mirror reconstruction group (P<0.05). Conclusions: The virtual reconstruction method based on GAN proposed in this study has better virtual reconstruction effect of unilateral defect than mirror technique, and can also realize virtual reconstruction of maxillary midspan defect.

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.

CT texture analysis-based nomogram for the preoperative prediction of visceral pleural invasion in cT1N0M0 lung adenocarcinoma: an external validation cohort study

AIM

To develop a nomogram based on computed tomography (CT) texture analysis for the preoperative prediction of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma.

MATERIALS AND METHODS

A dataset of chest CT containing lung nodules was collected from two institutions, and all surgically resected nodules were classified pathologically based on the presence of visceral pleural invasion. Each nodule on the CT image was segmented automatically by artificial-intelligence software and its CT texture features were extracted. The dataset was divided into training and external validation cohorts according to the institution, and a nomogram for predicting visceral pleural invasion was developed and validated.

RESULTS

Of a total of 313 patients enrolled from two independent institutions, 63 were diagnosed with visceral pleural invasion. Three-dimensional (3D) CT long diameter, skewness, and sphericity, and chronic obstructive pulmonary disease were identified as independent predictors for visceral pleural invasion by multivariable logistic regression. The nomogram based on multivariable logistic regression showed great discriminative ability, as indicated by a C-index of 0.890 (95% confidence interval [CI]: 0.867-0.914) and 0.864 (95% CI: 0.817-0.911) for the training and external validation cohorts, respectively. Additionally, calibration of the nomogram revealed good predictive ability, as indicated by the Brier score (0.108 and 0.100 for the training and external validation cohorts, respectively).

CONCLUSIONS

A nomogram was developed that could compute the probability of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma with good calibration and discrimination. The nomogram has potential as a reliable tool for clinical evaluation and decision-making.

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 plane^3-6, 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.

MiR-137 affects bone mineral density in osteoporosis rats through regulating RUNX2

OBJECTIVE

To study the influence of micro ribonucleic acid (miR)-137 on osteoporosis rats by regulating runt-related transcription factor 2 (RUNX2).

MATERIALS AND METHODS

A total of 36 Sprague-Dawley rats were randomly assigned to the normal group (n=12), model group (n=12), and inhibitor group (n=12). No treatment was performed in the normal group. The osteoporosis model in rats was prepared in the model group, and miR-137 inhibitor was administered in osteoporosis rats of inhibitor group. Following 12 weeks of intervention, sampling was conducted. The expression of RUNX2 was detected via immunohistochemistry, and its protein expression level was determined via Western blotting. Quantitative Polymerase Chain Reaction (qPCR) was carried out to detect the mRNA level of miR-137. The contents of serum bone Gla protein (BGP) and total alkaline phosphatase (TALP) were measured using enzyme-linked immunosorbent assay (ELISA). Finally, bone mineral density was determined with a dual-energy X-ray absorptiometry instrument.

RESULTS

According to the immunohistochemistry detection, the rats in model group and inhibitor group had a notably lower positive expression level of RUNX2 than normal group (p<0.05), and its expression level in the inhibitor group was substantially higher than that in the model group (p<0.05). Western blotting results showed that compared with that in the normal group, the protein expression level of RUNX2 was notably lowered in the model and inhibitor group (p<0.05), which was markedly higher in the inhibitor group than that in the model group (p<0.05). It was found through the qPCR that the expression level of miR-137 was remarkably raised in both model group and inhibitor group compared with that in the normal group, showing statistically significant differences (p<0.05). The rats in the inhibitor group had a remarkably lower expression level of miR-137 than the model group (p<0.05). ELISA results revealed that the model group and inhibitor group had substantially lower contents of serum BGP and TALP than the normal group (p<0.05), and that their contents rose dramatically in the inhibitor group compared with that in the model group (p<0.05). Additionally, based on the measurement of bone mineral density, compared with that in the normal group, bone mineral density declined considerably in the model group and inhibitor group (p<0.05). It was markedly elevated in inhibitor group in comparison with that in the model group (p<0.05).

CONCLUSIONS

MiR-137 regulates RUNX2 to affect the bone mineral density of osteoporosis model rats.

Opsin 5 is a key regulator of ultraviolet radiation-induced melanogenesis in human epidermal melanocytes

Background

Human skin, which is constantly exposed to solar ultraviolet radiation (UVR), has a unique ability to respond by increasing its pigmentation in a protective process driven by melanogenesis in human epidermal melanocytes (HEMs). However, the molecular mechanisms used by HEMs to detect and respond to UVR remain unclear.

Objectives

To investigate the function and potential mechanism of opsin 5 (OPN5), a photoreceptor responsive to UVR wavelengths, in melanogenesis in HEMs.

Methods

Melanin content in HEMs was determined using the NaOH method, and activity of tyrosinase (TYR) (a key enzyme in melanin synthesis) was determined by the l‐DOPA method. OPN5 expression in UVR‐treated vs. untreated HEMs and explant tissues was detected by reverse‐transcription quantitative polymerase chain reaction (RT‐qPCR), Western blotting and immunofluorescence. Short interfering RNA‐mediated OPN5 knockdown and a lentivirus OPN5 overexpression model were used to examine their respective effects on TYR, tyrosinase‐related protein 1 (TRP1), TRP2 and microphthalmia‐associated transcription factor (MITF) expression, under UVR. Changes in expression of TYR, TRP1 and TRP2 caused by changes in OPN5 expression level were detected by RT‐qPCR and Western blot. Furthermore, changes in signalling pathway proteins were assayed.

Results

We found that OPN5 is the key sensor in HEMs responsible for UVR‐induced melanogenesis. OPN5‐induced melanogenesis required Ca²⁺‐dependent G protein‐coupled receptor‐ and protein kinase C signal transduction, thus contributing to the UVR‐induced MITF response to mediate downstream cellular effects, and providing evidence of OPN5 function in mammalian phototransduction. Remarkably, OPN5 activation was necessary for UVR‐induced increase in cellular melanin and has an inherent function in melanocyte melanogenesis.

Conclusions

Our results provide insight into the molecular mechanisms of UVR sensing and phototransduction in melanocytes, and may reveal molecular targets for preventing pigmentation or pigment diseases.

What is already known about this topic?

Ultraviolet radiation (UVR) induces a protective response to DNA damage mediated by melanin synthesis in human epidermal melanocytes (HEMs).

Tyrosinase (TYR), with tyrosinase‐related proteins (TRP1, TRP2), are the key enzymes for melanin synthesis.

Microphthalmia‐associated transcription factor regulates key genes for melanocyte development and differentiation, and can stimulate melanogenesis by activating transcription of TYR and other pigmentation genes, including TRP1.

Opsin 5 (OPN5) is known to function as a photoreceptor responsive to wavelengths in the near UV spectrum.

What does this study add?

UVR induces melanogenesis in HEMs via OPN5.

OPN5 regulates expression of TYR, TRP1 and TRP2 through the calcium‐dependent G protein‐coupled and protein kinase C signalling pathways.

OPN5 has an inherent role in HEMs in mediating melanogenesis.

What is the translational message?

OPN5 was discovered as a key sensor for UVR‐induced melanogenesis in human skin melanocytes.

It could be a target for early treatment of pigmentation or pigment diseases, to provide a more personalized and economically feasible method.

Linked Comment: L.V.M. de Assis and A.M. de Lauro Castrucci. Br J Dermatol 2021; 185:249–250.

Plain language summary available online

LncRNA LINC00707 promotes osteogenic differentiation of hBMSCs through the Wnt/β-catenin pathway activated by LINC00707/miR-145/LRP5 axis

OBJECTIVE

Human bone marrow mesenchymal stem cells (hBMSCs) have a strong self-renewal potential and osteogenic differentiation ability, thus providing a new method for bone defect repair research. LncRNA LINC00707 participates in the regulation of osteogenic differentiation of hBMSCs and our aim was to explore the potential regulatory mechanism.

MATERIALS AND METHODS

Firstly, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression levels of LINC00707, miR-145, the low-density lipoprotein receptor-related protein 5 (LRP5) and osteogenesis-related genes. Next, alkaline phosphatase (ALP) activity assay was used to measure the relative activity of ALP in hBMSCs. The protein levels of LRP5 and osteogenesis-related genes were detected by Western blot. Finally, the relationship among LINC00707, miR-145 and LRP5 were predicted by online software and verified by Dual-Luciferase reporter assay, RNA pull-down and RNA immunoprecipitation (RIP).

RESULTS

LINC00707 and osteogenesis-related genes were gradually upregulated during osteogenesis of hBMSCs. Meanwhile, overexpression of LINC00707 promoted osteogenic differentiation of hBMSCs. Interestingly, we found that LINC00707 negatively regulated the miR-145 expression and osteogenic differentiation functions by directly interacting with miR-145, and LINC00707 affected the functions of LRP5 by sponging miR-145 in hBMSCs. Moreover, LINC00707 promoted the Wnt/β-catenin pathway through the LINC00707/miR-145/LRP5 axis.

CONCLUSIONS

LncRNA LINC00707 promoted osteogenic differentiation of hBMSCs by targeting LRP5 mediated by miR-145 through the activation of the Wnt/β-catenin pathway.

Effects of the prebiotic inulin-type fructans on post-antibiotic reconstitution of the gut microbiome

AIMS

Interventions using prebiotic inulin-type fructans (ITFs) are widely prescribed to modulate the gut microbiota composition and activity to promote health. However, the impacts of ITFs on post-antibiotic reconstitution of the gut microbiome remain incompletely understood. The aim of the present study was to investigate the effects of ITFs supplementation on intestinal inflammation, the composition of the intestinal microbiota and the colonic transcriptome after antibiotic treatment.

METHODS AND RESULTS

Male BALB/c mice were subjected to an antibiotic cocktail (ABx) treatment for 7 days, and their microbiomes were then reconstituted either spontaneously or with ITFs supplementation (5%) for 14 days. Our data showed that ITFs supplementation delayed the recovery of antibiotic-induced colitis compared with the spontaneous recovery. Neither ITFs supplementation nor spontaneous recovery could restore the microbial community composition at the genus level back to its initial composition. ITFs supplementation increased the relative abundance of some beneficial bacteria and butyrate levels, but resulted in selective blooms of some opportunistic pathogens and elevated the pathways associated with diseases linked to gut microbiota function. Both ITFs supplementation and spontaneous recovery could restore the colonic transcriptome nearly to the initial profile to a certain extent; however, ITFs supplementation delayed the restoration of the immunoglobulin genes compared to spontaneous recovery.

CONCLUSION

These data showed that post-antibiotic ITFs consumption did not always lead to beneficial effects but might lead to potential adverse effects in the context of dysbiosis.

SIGNIFICANCE AND IMPACT OF THE STUDY

These findings highlighted that caution is required when supplementing ITFs to restore intestinal homeostasis in the context of dysbiosis resulting from broad-spectrum antibiotics.

Clinical and immunologic features among COVID-19-affected mother-infant pairs: antibodies to SARS-CoV-2 detected in breast milk

The coronavirus disease 2019 (COVID-19) pandemic remains threatening to women and children, but clinical evidence regarding women during pregnancy, puerperium and lactation is limited. We assessed clinical and immunologic features of and breastfeeding advice provided to mother–infant pairs. This observational analysis was conducted in a tertiary-care centre in Wuhan, China. Pregnant patients with laboratory-confirmed COVID-19 who delivered during hospitalization were enrolled. Clinical characteristics and serial specimens of the mother–infant pairs were examined, supplemented with follow-ups regarding recovery and breastfeeding. Fourteen pregnant patients had live births and recovered well; four patients continued breastfeeding while taking precautions. No neonatal infections were observed. No infants developed COVID-19 during breastfeeding. Common maternal symptoms were fever (11/14, 78.1%) and cough (6/14, 42.9%). A pregnancy-specific symptom was abnormal foetal movement, which was noticed by three patients (21.4%). The mean virus shedding time was 9 days (standard deviation, 6 days; range, 1–22 days). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome was not detected in breast milk or maternal vaginal secretions. Immunologic assay revealed seroconversion of IgM on day 8 after onset and IgG on day 28. Both IgM and IgG antibodies to SARS-CoV-2 were detected in breast milk, cord blood and neonatal serum. The study results suggest that passive acquisition of antibodies against SARS-CoV-2 is available by ingesting breast milk. Breastfeeding has a low risk of transmitting SARS-CoV-2 or escalating maternal disease, so continuing breastfeeding with prudent precautions is encouraged.

TGR5-HNF4α axis contributes to bile acid-induced gastric intestinal metaplasia markers expression

Intestinal metaplasia (IM) increases the risk of gastric cancer. Our previous results indicated that bile acids (BAs) reflux promotes gastric IM development through kruppel-like factor 4 (KLF4) and caudal-type homeobox 2 (CDX2) activation. However, the underlying mechanisms remain largely elusive. Herein, we verified that secondary BAs responsive G-protein-coupled bile acid receptor 1 (GPBAR1, also known as TGR5) was increased significantly in IM specimens. Moreover, TGR5 contributed to deoxycholic acid (DCA)-induced metaplastic phenotype through positively regulating KLF4 and CDX2 at transcriptional level. Then we employed PCR array and identified hepatocyte nuclear factor 4α (HNF4α) as a candidate mediator. Mechanically, DCA treatment could induce HNF4α expression through TGR5 and following ERK1/2 pathway activation. Furthermore, HNF4α mediated the effects of DCA treatment through directly regulating KLF4 and CDX2. Finally, high TGR5 levels were correlated with high HNF4α, KLF4, and CDX2 levels in IM tissues. These findings highlight the TGR5-ERK1/2-HNF4α axis during IM development in patients with BAs reflux, which may help to understand the mechanism underlying IM development and provide prospective strategies for IM treatment.

Knowledge, Attitude and Preventive Practice on Dementia Care among Primary Health Professionals in Macao

The Macao Dementia Policy was recognized by Alzheimer Disease International as the 27th globally and one of the highest stage 5 to develop dementia friendly community and primary health professionals are in a pivotal position to enhance community-based dementia prevention and care quality. This study aimed to investigate the knowledge, attitude and preventive practice on dementia care among primary health professionals in Macao. A specially designed 30-item questionnaire was developed and validated for the study. The Content Validity Index (CVI) and Cronbach's α of the questionnaire were 0.973 and 0.808. The questionnaires were distributed to all 375 primary health professionals from 8 Health Centers throughout Macao and 234 valid questionnaires (62.4%) were returned. The score for dementia care knowledge was 87.02±14.01; attitude was 69.52±5.83; preventive practice was 77.88±13.18, of which doctors (79.89±13.77) was significantly higher (t=2.29, p=0.023) than nurses (75.91±12.33). There were positive relationships between preventive practice and attitude (r=0.163, p=0.014), and age (r=0.212, p=0.002), and a negative relationship between knowledge and age (r=-0.139, p=0.040). These findings have significant implications that most primary health professionals in Macao had sufficient knowledge, a positive attitude and appropriate preventive practice on dementia care. However, enhanced dementia education to improve knowledge and preventive practice was a strong agenda for the training for senior staff and nurses.

IKKε aggravates inflammatory response via activation of NF-κB in rheumatoid arthritis

OBJECTIVE

Rheumatoid Arthritis (RA) is a chronic systemic autoimmune disease, whereas its cause still remains elusive. Typical pathological manifestations of RA include persistent synovitis and bone degeneration in the surrounding joints. Although the incidence of RA is high in population, currently there have been no effective cures for it. The purpose of this study is to investigate the therapeutic effects and main mechanism of IKKε (inhibitor of nuclear factor kappa-B kinase ε) in collagen II induced- Rheumatoid Arthritis (CIA) mice model.

MATERIALS AND METHODS

IKKε-/- and wild-type (WT) littermate control mice were intraperitoneally injected with 5 mg/kg collagen II monoclonal antibody cocktail (Cab) for 5 days. After that, the nociception threshold and clinical rheumatoid arthritis articular damage score of mice were evaluated. After 5 days-CAb treatment, serum levels of a series of inflammatory cytokines including interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNF-α) and interferon (IFN) were detected with enzyme-linked immunosorbent assay (ELISA) in both groups. Besides, Real-time reverse transcription polymerase chain reaction (Real-time RT-PCR) was used to evaluate the expression of these inflammatory cytokines in plantar tissues. In addition, Western blot was performed to investigate the protein levels of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B) signaling pathway. Moreover, WT mice receiving CAb were further applied with or without IKK inhibitor amlexanox (25 mg/kg) to investigate the expression of the above-mentioned inflammatory cytokines.

RESULTS

Our work showed that IKKε-/- mice with CIA displayed less nociception and suppressed inflammatory response than WT mice. Meanwhile, the clinical rheumatoid arthritis articular damage scores were significantly decreased in IKKε-/- mice. The levels of TNF-α, IL-1β, IL-6 in serum and plantar tissues in IKKε-/- mice were significantly lower than those in WT mice. Besides, NF-κB expression in IKKε-/- mice was significantly decreased. Similarly, the same phenotype was observed in WT mice administrated with IKKε inhibitor amlexanox as that of IKKε-/- mice, indicating that inflammatory and nociception responses were remarkably decreased than those of the negative controls.

CONCLUSIONS

IKKε plays an important role in promoting nociception and inflammatory response in CIA. Our research demonstrated that knockout of IKKε may serve as a new direction for clinical prevention and treatment of rheumatoid arthritis. IKKε inhibitor amlexanox may become a new drug for the treatment of rheumatoid arthritis.

[Pilot study of the relationship between clinical classification of gallbladder cancer and prognosis: a retrospective multicenter clinical study]

Objectives: To propose a novel clinical classification system of gallbladder cancer, and to investigate the differences of clinicopathological characteristics and prognosis based on patients who underwent radical resection with different types of gallbladder cancer. Methods: The clinical data of 1 059 patients with gallbladder cancer underwent radical resection in 12 institutions in China from January 2013 to December 2017 were retrospectively collected and analyzed.There were 389 males and 670 females, aged (62.0±10.5)years(range:22-88 years).According to the location of tumor and the mode of invasion,the tumors were divided into peritoneal type, hepatic type, hepatic hilum type and mixed type, the surgical procedures were divided into regional radical resection and extended radical resection.The correlation between different types and T stage, N stage, vascular invasion, neural invasion, median survival time and surgical procedures were analyzed.Rates were compared by χ(2) test, survival analysis was carried by Kaplan-Meier and Log-rank test. Results: Regional radical resection was performed in 940 cases,including 81 cases in T1 stage,859 cases in T2-T4 stage,119 cases underwent extended radical resection;R0 resection was achieved in 990 cases(93.5%).The overall median survival time was 28 months.There were 81 patients in Tis-T1 stage and 978 patients in T2-T4 stage.The classification of gallbladder cancer in patients with T2-T4 stage: 345 cases(35.3%)of peritoneal type, 331 cases(33.8%) of hepatic type, 122 cases(12.5%) of hepatic hilum type and 180 cases(18.4%) of mixed type.T stage(χ(2)=288.60,P<0.01),N stage(χ(2)=68.10, P<0.01), vascular invasion(χ(2)=128.70, P<0.01)and neural invasion(χ(2)=54.30, P<0.01)were significantly correlated with the classification.The median survival time of peritoneal type,hepatic type,hepatic hilum type and mixed type was 48 months,21 months,16 months and 11 months,respectively(χ(2)=80.60,P<0.01).There was no significant difference in median survival time between regional radical resection and extended radical resection in the peritoneal type,hepatic type,hepatic hilum type and mixed type(all P>0.05). Conclusion: With application of new clinical classification, different types of gallbladder cancer are proved to be correlated with TNM stage, malignant biological behavior and prognosis, which will facilitate us in preoperative evaluation,surgical planning and prognosis evaluation.