A bimodal burst energy distribution of a repeating fast radio burst source.

The event rate, energy distribution and time-domain behaviour of repeating fast radio bursts (FRBs) contain essential information regarding their physical nature and central engine, which are as yet unknown1,2. As the first precisely localized source, FRB 121102 (refs. 3-5) has been extensively observed and shows non-Poisson clustering of bursts over time and a power-law energy distribution6-8. However, the extent of the energy distribution towards the fainter end was not known. Here we report the detection of 1,652 independent bursts with a peak burst rate of 122 h-1, in 59.5 hours spanning 47 days. A peak in the isotropic equivalent energy distribution is found to be approximately 4.8 × 1037 erg at 1.25 GHz, below which the detection of bursts is suppressed. The burst energy distribution is bimodal, and well characterized by a combination of a log-normal function and a generalized Cauchy function. The large number of bursts in hour-long spans allows sensitive periodicity searches between 1 ms and 1,000 s. The non-detection of any periodicity or quasi-periodicity poses challenges for models involving a single rotating compact object. The high burst rate also implies that FRBs must be generated with a high radiative efficiency, disfavouring emission mechanisms with large energy requirements or contrived triggering conditions.

No pulsed radio emission during a bursting phase of a Galactic magnetar.

Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources4-13, but no convincing evidence has been collected so far14. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft γ-ray bursts15. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft γ-ray/hard-X-ray flare18-21. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-γ-ray repeater (SGR) bursts were detected in γ-ray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB-SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst.

[Annual review of progress in research on chronic obstructive pulmonary disease(2022-2023)].

Chronic obstructive pulmonary disease (COPD) is the most common chronic airway disease, with a high prevalence and high disease burden. Clinical questions have driven advances in clinical research that continue to deepen our understanding of COPD. At the same time, new perspectives, evidence, and strategies have emerged. Studies since 2022 have increased knowledge of the impact of risk factors, such as low-to-moderate income and ambient ozone, on the prevalence of COPD. The effect of preterm birth on obstructive lung function deficits and COPD in the sixth decade of life was investigated for the first time. Screening studies for COPD in developed and low- and middle-income countries suggest the importance of tailoring screening strategies to local conditions. Developments in artificial intelligence provide a general framework for using machine-learning-based methods and medical record-based labels to improve disease prediction. New perspectives on endotypes/phenotypes and prognostic assessment of COPD were provided by lifetime spirometry patterns of obstruction and limitation, sensitisation to recombinant Aspergillus fumigatus allergens, airway-occluding mucus plugs and exacerbation history in COPD group A and B patients. Clinical trials focusing on inflammatory mediators, comorbidity treatment, non-pharmacological treatments, and environmental interventions shed light on some crucial and long-debated issues. Further research is needed for individualised diagnosis and treatment of COPD.

[A survey on the practice of bronchoscopy in county-level hospitals of China].

Objective: To investigate the bronchoscopy resource allocation and technology application in county-level hospitals in China. Methods: A cross-sectional survey was conducted. In 2021, 12 provinces were sampled from all provinces in China according to the regional Gross Domestic Product (GDP) and the number of counties, in which a total of 291 county-level hospitals were randomly enrolled. Two county-level hospitals which carried out bronchoscopy technology in each province were randomly sampled to investigate the status of bronchoscopy resources, technical application, decontamination and anesthesia by using questionnaires. Independent sample t test or two related sample nonparametric test were used for comparison between groups. Spearman correlation analysis was used to explore the correlation. Bilateral P<0.05 was considered statistically significant. Results: According to the sampling results, it was estimated that in the county-level hospitals, the proportion of those performing bronchoscopy was 11.4% (9.9%, 13.8%), which was significantly correlated with the population in the province (r=0.64, P=0.025) and the regional GDP (r=0.65, P=0.025).The 24 county-level hospitals interviewed were equipped with (1.6±1.0) bronchoscopes on average, and the number of hospitals with electronic bronchoscopes and fiberoptic bronchoscopes was 22 (91.7%) and 6 (25.0%), respectively. Six (25.0%) hospitals performed bronchoscopy every working day. Twelve (50.0%) hospitals had relatively permanent physicians and nurses. All operating doctors had received special training. There was a significant increase in the number of bronchoscopy cases per hospital in 2020 compared to 2019 [140(70, 335) vs. 100(29, 254), P=0.001]. All hospitals used standard cleaning and sterilization workbenches, cleaning agents and disinfectants. Surface anesthesia was available in 24 hospitals, and bronchoscopy techniques under sedation and analgesia were performed in 10 (41.7%) hospitals. Atropine was still used to prevent airway secretions in 2 (8.3%) hospitals,although not recommended by guidelines. Conclusions: There was a large gap between the current status of bronchoscopy technology in county-level hospitals and the standards of the National Health Commission, together with regional disparities. Bronchoscopist training in the standardization and the decontamination work met the requirements. In some hospitals, the use of complementary medicines was not standardized or the sedatives were not given routinely according to the guidelines. We should promote the popularization and standardization of bronchoscopy technology, and strengthen the allocation of related resources in China's county hospitals.

[Clinical characteristics of patients infected with 2019-nCoV Omicron variants BA.2 and BA.5 in Xi'an city, China].

Objective: To analyze the epidemiological and clinical characteristics of patients infected with different subtype of 2019-nCoV Omicron variants BA.2 and BA.5 in Xi'an city. Methods: A retrospective observational study was conducted to collect data of 168 patients infected with Omicron variant admitted to the designated hospital for COVID-19 charged by Xi'an Chest Hospital during 2022. Data were collected including epidemiological, clinical features, laboratory and viral load, and the difference between BA.2 and BA.5 subtype was analyzed. Results: A total of 168 patients were admitted, including 122 cases infected with BA.2 subtype, and 46 cases infected with BA.5 subtype. Patients infected with BA.2 subtype had a higher rate of cough than BA.5 subtype (43.44%∶23.91%; P=0.021). Compared with the Omicron variant BA.2, patients infected with BA.5 subtype had a higher proportion of asymptomatic and mild infections (89.13%∶68.85%; P<0.001), higher rate of vaccination (95.66%∶68.03%; P<0.001), shorter time to nucleic acid negative conversion (8.62; P=0.047), and a higher viral load at admission (P=0.005, P=0.017). Conclusions: The Omicron variant is extremely infectious with aggregated onset, but its clinical symptoms are mild. The vaccine, especially the booster vaccination, remains effective in preventing severe stage progression and improving prognosis in patients with Omicron variant infection.

Identification of genes associated with litter size combining genomic approaches in Luzhong mutton sheep.

Litter size is one of the most important reproductive traits of sheep, which has pronounced effects on the profit of husbandry enterprises and enthusiasm of breeders. Despite the importance of litter size, the underlying genetic mechanisms have not been entirely elucidated. Therefore, based on a high-density SNP chip, genome-wide comparative analysis was performed between two groups with different fecundity to reveal candidate genes linked to litter size via detection of homozygosity and selection signatures in Luzhong mutton sheep. Consequently, nine promising genes were identified from six runs of homozygosity islands, and functionally linked to reproduction (ACTL7A, ACTL7B, and ELP1), embryonic development (KLF5 and PIBF1), and cell cycle (DACH1, BORA, DIS3, and MZT1). A total of 128 genes were observed under selection, of which HECW1 and HTR1E were related to total lambs born, GABRG3, LRP1B, and MACROD2 to teat number, and AGBL1 to reproductive seasonality. Additionally, the presence of inbreeding depression implies the urgency of reasonable mating system to increase litter size in the present herd. These findings provide a comprehensive insight to the genetic makeup of litter size, and also contribute to implementation of marker-assisted selection in sheep.

Genome-wide association study and inbreeding depression on body size traits in Qira black sheep (Ovis aries).

Qira black sheep is a famous indigenous sheep breed in China. The objectives of this study are to identify candidate genes related to body size, and to estimate the level of inbreeding depression on body size based on runs of homozygosity in Qira black sheep. Here, 188 adult Qira black sheep were genotyped with a high density (630 K) SNP chip and genome-wide association study for body weight and body size traits (including withers height, body slanting length, tail length, chest girth, chest width, and chest depth) were performed using an additive linear model. In consequence, 12 genome- and chromosome-wide significant SNPs and, accordingly, six candidate genes involved in muscle differentiation, metabolism and cell processes were identified. Of them, ZNF704 (zinc finger protein 704) was identified for body weight; AK2 (adenylate kinase 2) and PARK2 (parkin RBR E3 ubiquitin protein ligase) for tail length; MOCOS (molybdenum cofactor sulfurase) and ELP2 (elongator acetyltransferase complex subunit 2) for chest width; and MFAP1 (microfibril associated protein 1) for chest girth. Additionally, inbreeding depressions on body size were observed in the current herd. These results will provide insightful understandings into the genetic mechanisms of adult body size, and into the conservation and utilization of Qira black sheep.

[Value of fibrinogen to albumin ratio on predicting spontaneous recanalization of infarct-related artery in patients with acute ST-segment elevation myocardial infarction].

Objective: To investigate the value of fibrinogen to albumin ratio (FAR) at admission on predicting spontaneous recanalization of infarct-related artery (IRA) in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods: Clinical data from 255 acute STEMI patients ((61.1±11.2) years old, 189 males) who underwent emergency coronary angiography within 12 hours in our hospital from December 2015 to April 2018 were retrospectively analyzed. The acute STEMI patients were divided into non-spontaneous recanalization group (thrombolysis in myocardial infarction (TIMI) flow grade 0-1, 203 cases) and spontaneous recanalization group (TIMI flow grade 2-3, 52 cases). Multivariate logistic regression analysis was used to evaluate related factors of IRA spontaneous recanalization. The receiver operating characteristic (ROC) curve was used to evaluate the value of FAR in predicting spontaneous coronary recanalization. Results: There was no significant difference in age,gender, hypertension, diabetes, smoking,systolic blood pressure,diastolic blood pressure,heart rate, duration of chest pain, type of infarction, infarct-related artery, door-to-balloon time, and drug used before admission between non-spontaneous recanalization group and spontaneous recanalization group (all P>0.05). The FAR and high-sensitivity C-reactive protein levels were significantly lower in the spontaneous recanalization group than in the non-spontaneous recanalization group (8.20±1.85 vs. 11.02±2.75, P<0.001; (6.87±3.36) g/L vs. (8.51±3.72) g/L, P=0.004). Multivariate logistic regression analysis showed that FAR (OR=0.492, 95%CI 0.354-0.686, P<0.001), serum uric acid (OR=0.994, 95%CI 0.989-0.999, P=0.018) and high-sensitivity C-reactive protein (OR=0.774, 95%CI 0.614-0.975, P=0.030) were independent negative correlation with spontaneous recanalization of infarct-related artery in patients with acute STEMI. The ROC curve showed that the area under the curve of FAR predicting spontaneous recanalization of infarct-related artery in patients with acute STEMI was 0.807 (95%CI 0.630-0.758, P<0.001), and the diagnostic threshold was 9.26, the sensitivity was 76.9%, the specificity was 75.9%. Conclusion: The level of admission FAR has certain predictive value for spontaneous recanalization of infarct-related arteries in patients with acute STEMI.

[Analysis of influencing factors of heart rate deceleration capacity in patients with dilated cardiomyopathy].

Objective: To investigate the determinants affecting the heart rate deceleration capacity (DC) in patients with dilated cardiomyopathy (DCM). Methods: One hundred patients with DCM (DCM group) and 202 healthy subjects (control group) were respectively enrolled. Echocardiography and 24 hours electrocardiogram were performed in all subjects. DC value was compared between the two groups. Multiple regression analysis was made to evaluate the related determinants of DC ((age, sex, echocardiographic parameters including the left atrial diameter (LAD) and left ventricular ejection fraction (LVEF)). Results: (1) DC value was significantly lower in DCM group than in control group( (4.40±2.03) ms vs. (7.30±1.81) ms, P<0.01), prevalence of DC value≤4.5 ms was significantly higher in DCM group than in control group (62% vs. 6%, P<0.01). (2) DC value in the DCM group decreased in proportion to increasing LAD dimension, DC value was (5.60±2.04) ms, (4.50±2.07) ms and (3.60±1.62) ms (P<0.05) in DCM patients with LAD≤40 mm, 40 mm50 mm, respectively. (3) DC value in the DCM group was negatively related to the LAD (r=-0.366, P<0.01), positively related to the LVEF (r= 0.241, P<0.01), but not related with age and sex. Multiple factors regression analysis showed that increased LAD was related to the reduced DC values independtly. Conclusion: DC value of the patients in the DCM group is decreased, which indicate the decrease of the vagus nerve tension, and increased LAD is related to the reduced DC value independtly in DCM patients.

Dynamic changes of virus load in supernatant of primary CEK cell culture infected with different generations of avian infectious bronchitis virus strains Sczy3 as revealed by real-time reverse transcription-polymerase chain reaction.

Infectious bronchitis virus (IBV) can multiply effectively in chick embryo kidney (CEK) cells after adapting to the chick embryo. To investigate the dynamic changes in IBV load in the supernatant of primary CEK cells, we developed an SYBR Green I-based real-time polymerase chain reaction assay to quantify nucleic copy numbers of the IBV-Sczy3 strain. The 20, 54, and 87th generations of CEK-adapted IBV-Sczy3 strains were used to infect CEK cells, and then nucleic copy numbers in the samples of supernatant collected at 12, 24, 36, 48, 60, and 72 h were detected. The results showed that the rapid growth period of the virus load of all the 3 generations was approximately 12-36 h post-infection; the peak of the virus load appeared at 36 h post-infection and then decreased gradually in the order of 20th > 54th > 87th for the 3 generations of CEK-adapted strains; the dynamic change curve of the IBV load in the supernatant of primary CEK cells showed a single peak. The results of this study provide a useful reference for CEK-adapted IBV field strains and the production of CEK-attenuated IBV vaccine.

Gambogic acid synergistically potentiates cisplatin-induced apoptosis in non-small-cell lung cancer through suppressing NF-κB and MAPK/HO-1 signalling.

BACKGROUND: Gambogic acid (GA) has been reported to have potent anticancer activity and is authorised to be tested in phase II clinical trials for treatment of non-small-cell lung cancer (NSCLC). The present study aims to investigate whether GA would be synergistic with cisplatin (CDDP) against the NSCLC. METHODS: 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT), combination index (CI) isobologram, western blot, quantitative PCR, flow cytometry, electrophoretic mobility shift assay, xenograft tumour models and terminal deoxynucleotide transferase-mediated dUTP nick-end labelling analysis were used in this study. RESULTS: The cell viability results showed that sequential CDDP-GA treatment resulted in a strong synergistic action in A549, NCI-H460, and NCI-H1299 cell lines, whereas the reverse sequence and simultaneous treatments led to a slight synergistic or additive action. Increased sub-G1 phase cells and enhanced PARP cleavage demonstrated that the sequence of CDDP-GA treatment markedly increased apoptosis in comparison with other treatments. Furthermore, the sequential combination could enhance the activation of caspase-3, -8, and 9, increase the expression of Fas and Bax, and decrease the expression of Bcl-2, survivin and X-inhibitor of apoptosis protein (X-IAP) in A549 and NCI-H460 cell lines. In addition, increased apoptosis was correlated with enhanced reactive oxygen species generation. Importantly, it was found that, followed by CDDP treatment, GA could inhibit NF-κB and mitogen-activated protein kinase (MAPK)/heme oxygenase-1 (HO-1) signalling pathways, which have been validated to reduce ROS release and confer CDDP resistance. The roles of NF-κB and MAPK pathways were further confirmed by using specific inhibitors, which significantly increased ROS release and apoptosis induced by the sequential combination of CDDP and GA. Moreover, our results indicated that the combination of CDDP and GA exerted increased antitumour effects on A549 xenograft models through inhibiting NF-κB, HO-1, and subsequently inducing apoptosis. CONCLUSION: Gambogic acid sensitises lung cancer cells to CDDP in vitro and in vivo in NSCLC through inactivation of NF-κB and MAPK/HO-1 signalling pathways, providing a rationale for the combined use of CDDP and GA in lung cancer chemotherapy.

Analysis of the linear epitope for Fc-binding on the mouse IgG Fc receptor (moFcγRI) by synthetic peptide.

To identify the linear epitope for Fc-binding to the mouse immunoglobulin G (IgG) Fc receptor (moFcγRI), peptides derived from the membrane-distal extracellular domain (EC2) of moFcγRI, corresponding to the homologous region of human FcγRI (huFcγRI) and huFcγRII, were synthesized. Using a dot-blot assay, six peptides were tested. The results showed that the moRI3 peptide (CVFYRNGKSFQFS) could combine with mouse IgG efficiently. A competitive enzyme-linked immunosorbent assay (ELISA) showed that the IC50 value of the moRI3 peptide was 38.03 mM. The moRI3 peptide could inhibit the combination of mouse IgG to the transfected COS 7 cells significantly with an IC50 value of 72.68 mM. The IgG-binding region of moFcγRI was also localized in the C'-E loop of the EC2 domain as predicted according to huFcγRI and huFcγRII. We predicted that the minimum effective IgG-binding region of moFcγRI may be the peptide 153SFQFSS158. The linear epitope for immunoglobulin-binding to mouse FcγR is also described. Thus, we generated a peptide that targets a fundamental aspect of ligand recognition by this receptor class.

Amplification of the telomerase RNA component gene as a new genetic marker for disease progression and prognosis in esophageal squamous cell carcinoma.

Amplification of the human telomerase RNA component (TERC) gene was found in esophageal squamous cell carcinoma (ESCC). However, its roles in the progression and prognosis of ESCC have not been well understood. The amplification of TERC in normal mucosa, low-grade and high-grade intraepithelial neoplasia, and invasive ESCC samples were evaluated using a fluorescence in situ hybridization assay. The amplification of TERC invariably occurred in high-grade intraepithelial neoplasia and invasive ESCC, partially occurred in low-grade intraepithelial neoplasia specimens, and seldom occurred in normal mucosa. The average signal ratio of TERC to chromosome 3 centromere-specific probe (TERC/CSP3) was 1.00 ± 0.01 (average ± standard deviation) in normal mucosas, 1.01 ± 0.08 in low-grade intraepithelial neoplasias, 1.39 ± 0.26 in high-grade intraepithelial neoplasias, and 1.56 ± 0.41 in invasive ESCC. High TERC/CSP3 ratio was positively associated with lymph node metastasis (P = 0.005) and advanced tumor stage (P = 0.045). Patients with high amplification of TERC had poor survival (P = 0.01). The amplification of TERC could be used as a new genomic marker for disease progression and prognosis of ESCC. The amplified TERC gene may be a potential therapeutic target for ESCC.

Design and experiments of a compact electrostatic low energy beam transport with a double Einzel-lens for a transportable neutron source.

A transportable, compact, accelerator-based neutron source is under development at Xian Jiaotong University. An electrostatic low energy beam transport (LEBT) structure with a double Einzel-lens setup was adopted due to its short length and low power consumption. It can transport a pulsed proton beam to the radio frequency quadrupole with a required beam current of 15 mA and an energy of 30 keV. We performed detailed structure optimization and beam tracking to achieve beam matching and small emittance growth. In addition, the fast chopper, beam steering, and diagnostic devices are integrated into the LEBT. The fabrication and assembly of the proton injector have been completed, and beam commissioning was carried out to measure the beam current and Twiss parameters. The design strategy, beam simulation, and experimental results are presented and discussed in this paper.

[A clustered epidemic investigation of non-marital non-commercial heterosexual contact of HIV in Zhejiang Province].

Objective: To identify the transmission relationship between HIV infection cases the non-marital non-commercial heterosexual contact in Zhejiang Province. Methods: When HIV positive was informed during January 2020 to January 2022, the staff conducted an epidemiological investigation to collect cases information on sociodemographic characteristics, mobility information, past HIV testing history, high-risk sexual behaviors, sexual partners, and etcetera. At the same time, 6-8 ml of blood from the new diagnosis of people infected with HIV before antiviral treatment was collected to separate the bleeding plasma. pol gene was amplified by nucleic acid extraction and PCR, sequenced by Sequencer 5.0 software, and Cytoscape 3.6.0 software was used to draw HIV molecular transmission network. Results: From January 2020 to January 2022, 88 HIV infected individuals were found in Pujiang County, of which 74 were transmitted through heterosexual transmission, of which 31 were infected through non-marital non-commercial heterosexual contact. Preliminary case studies have found that three female cases have engaged in unprotected non-marital non-commercial heterosexual contact with one male case. Among the 4 infected individuals, 2 of their spouses tested positive for HIV antibodies. Molecular transmission network monitoring was carried out on 65 newly diagnosed cases of heterosexual transmission with acquired sequences, forming 9 transmission clusters. The largest cluster contained 10 cases. A total of 11 HIV-infected individuals were involved in this HIV cluster epidemic. They were 3 males and 8 females, all over 50 years old and were farmers or rural housewives. They were traced to 7 sexual partners (6 negatives of HIV, 1 undetected). Among the 18 respondents' sexual social network relationships, there were 6 couples, 8 permanent partners, and 3 temporary partners. Among 11 HIV infected individuals, there were 9 cases of non-marital non-commercial heterosexual transmission and 2 cases of intramarital transmission. The epidemiological association between 7 non-married non-commercial heterosexual partners and case 2 (56-year-old male farmer), 3 cases confirmed by epidemiological investigation and molecular transmission cluster results, 3 cases confirmed by molecular transmission cluster and epidemiological investigation results, and 1 case confirmed by epidemiological investigation results. Conclusions: The transmission mode of this cluster epidemic was to spread HIV through heterosexual sex with a male case as the core, then cause the transmission within marriage and between fixed sexual partners. The combination of epidemiological investigation and molecular transmission network traceability survey supports the conclusion of this study.