A fast radio burst source at a complex magnetized site in a barred galaxy.

Fast radio bursts (FRBs) are highly dispersed, millisecond-duration radio bursts1-3. Recent observations of a Galactic FRB4-8 suggest that at least some FRBs originate from magnetars, but the origin of cosmological FRBs is still not settled. Here we report the detection of 1,863 bursts in 82 h over 54 days from the repeating source FRB 20201124A (ref. 9). These observations show irregular short-time variation of the Faraday rotation measure (RM), which scrutinizes the density-weighted line-of-sight magnetic field strength, of individual bursts during the first 36 days, followed by a constant RM. We detected circular polarization in more than half of the burst sample, including one burst reaching a high fractional circular polarization of 75%. Oscillations in fractional linear and circular polarizations, as well as polarization angle as a function of wavelength, were detected. All of these features provide evidence for a complicated, dynamically evolving, magnetized immediate environment within about an astronomical unit (AU; Earth-Sun distance) of the source. Our optical observations of its Milky-Way-sized, metal-rich host galaxy10-12 show a barred spiral, with the FRB source residing in a low-stellar-density interarm region at an intermediate galactocentric distance. This environment is inconsistent with a young magnetar engine formed during an extreme explosion of a massive star that resulted in a long gamma-ray burst or superluminous supernova.

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.

Experimental Evidence of Plasmoids in High-ß Magnetic Reconnection.

Magnetic reconnection is a ubiquitous and fundamental process in plasmas by which magnetic fields change their topology and release magnetic energy. Despite decades of research, the physics governing the reconnection process in many parameter regimes remains controversial. Contemporary reconnection theories predict that long, narrow current sheets are susceptible to the tearing instability and split into isolated magnetic islands (or plasmoids), resulting in an enhanced reconnection rate. While several experimental observations of plasmoids in the regime of low-to-intermediate ß (where ß is the ratio of plasma thermal pressure to magnetic pressure) have been made, there is a relative lack of experimental evidence for plasmoids in the high-ß reconnection environments which are typical in many space and astrophysical contexts. Here, we report strong experimental evidence for plasmoid formation in laser-driven high-ß reconnection experiments.

Exploration of clinical and ethical issues in an expanded newborn metabolic screening programme: a qualitative interview study of healthcare professionals in Hong Kong.

INTRODUCTION: The Newborn Screening Programme for Inborn Errors of Metabolism (NBSIEM) enables early intervention and prevents premature mortality. Residual dried bloodspots (rDBS) from the heel prick test are a valuable resource for research. However, there is minimal data regarding how stakeholders in Hong Kong view the retention and secondary use of rDBS. This study aimed to explore views of the NBSIEM and the factors associated with retention and secondary use of rDBS among healthcare professionals in Hong Kong. METHODS: Between August 2021 and January 2022, semi-structured interviews were conducted with 30 healthcare professionals in obstetrics, paediatrics, and chemical pathology. Key themes were identified through thematic analysis, including views towards the current NBSIEM and the retention and secondary use of rDBS. RESULTS: After implementation of the NBSIEM, participants observed fewer patients with acute decompensation due to undiagnosed inborn errors of metabolism. The most frequently cited clinical utilities were early detection and improved health outcomes. Barriers to rDBS storage and its secondary use included uncertain value and benefits, trust concerns, and consent issues. CONCLUSION: This study highlighted healthcare professionals' concerns about the NBSIEM and uncertainties regarding the handling or utilisation of rDBS. Policymakers should consider these concerns when establishing new guidelines.

[Clinical outcome of posterior lumbar interbody fusion combined with Ponte osteotomy for reconstruction of coronal sagittal plane balance in degenerative scoliosis].

Objective: To evaluate the clinical efficacy of posterior lumbar interbody fusion combined with Ponte osteotomy in the treatment of patients with degenerative scoliosis. Methods: The medical records and imaging data of degenerative scoliosis in department of orthopedics, Peking Union Medical College Hospital from 2013 to 2022 were retrospectively collected, and the shortest follow-up time was 1 year. A total of 38 patients were included, including 13 males and 25 females, aged 50-87(65.6±10.9) years old.The follow-up was12-119(43±20) months. Standing position full spine anteroposterior lateral X-ray examinations were performed on all patients preoperatively, postoperatively, and at latest follow-up. The length of hospital stay, complications, operation time, blood loss, instrumented segment, fusion segmen were recorded. The clinical scores and coronasagittal imaging indicators at three time points were compared. Results: The operation time was (274.5±70.5)min, and intraoperative blood loss was (619.2±93.5)ml. The coronal vertical axis was improved from (2.9±1.8)cm preoperatively to (1.2±1.0)cm postoperatively. The preoperative coronal Cobb angle was 16.6°±9.9° and the immediate postoperative correction was 6.4°±4.0°(t=-6.83, P<0.001). The difference was statistically significant (t=-6.12, P<0.001). The coronal Cobb Angle at the last follow-up was 5.7°±3.7°, and there was no significant orthopaedic loss at the last follow-up (t=-6.12, P<0.001).The sagittal vertical axis decreased from (5.6±3.9)cm preoperatively to (3.2±2.5) cm immediately after operation (t=-6.83,P<0.001), and was well maintained at the last follow-up[(2.7±1.8) cm,t=-7.77,P<0.001]. Lumbar lordosis increased from 21.8°±10.2° preoperatively to 35.8°±8.3° postoperatively(t=12.01, P<0.001)and 40.1°±8.6° at last follow-up(t=-10.21, P<0.001). Oswestry disability score (ODI score), visual analogue score (VAS) low back pain score and VAS leg pain score were also lower after surgery than before surgery (all P<0.05). Conclusion: Posterior lumbar interbody fusion combined with Ponte osteotomy can significantly improve the coronal and sagittal plane deformity and postoperative functional score in adult patients with degenerative scoliosis.

Effect of Strongly Magnetized Electrons and Ions on Heat Flow and Symmetry of Inertial Fusion Implosions.

This Letter presents the first observation on how a strong, 500 kG, externally applied B field increases the mode-two asymmetry in shock-heated inertial fusion implosions. Using a direct-drive implosion with polar illumination and imposed field, we observed that magnetization produces a significant increase in the implosion oblateness (a 2.5× larger P2 amplitude in x-ray self-emission images) compared with reference experiments with identical drive but with no field applied. The implosions produce strongly magnetized electrons (ω_{e}τ_{e}≫1) and ions (ω_{i}τ_{i}>1) that, as shown using simulations, restrict the cross field heat flow necessary for lateral distribution of the laser and shock heating from the implosion pole to the waist, causing the enhanced mode-two shape.

Paediatric high-grade osteosarcoma and its prognostic factors: a 10-year retrospective study.

INTRODUCTION: This retrospective study was conducted to identify the characteristics of paediatric high-grade osteosarcoma and define its prognostic factors. METHODS: We identified paediatric patients (aged <19 years at diagnosis) diagnosed with high-grade osteosarcoma from 1 January 2009 to 31 December 2018 in two hospitals in Hong Kong, then retrospectively evaluated their medical records to identify prognostic factors. RESULTS: In total, 52 patients were included in this study (22 girls, 42.3%). Femoral tumour was the most common form of osteosarcoma. Most patients (78.8%) had localised disease at diagnosis. The lung was the most common site of metastasis. Almost half (n=23, 46.9%) of the patients showed a good response to chemotherapy (ie, chemonecrosis >90%). Most patients (n=40, 80%) underwent limb-salvage surgery. The event-free survival and overall survival rates were 55.8% and 71.2%, respectively. Prognostic factors independently associated with poor event-free survival and poor overall survival were the presence of metastasis at diagnosis, poor tumour chemonecrosis, and the need for amputation. CONCLUSION: This multicentre review of paediatric high-grade osteosarcoma showed that the baseline patient demographics, event-free survival, and overall survival in Hong Kong were similar to previous findings in other countries. Patients with metastatic disease at diagnosis and poor chemonecrosis had worse survival outcomes. Molecular analyses of genetic abnormalities may help to identify targeted therapies in future studies.

Health behaviour practices and expectations for a local cancer survivorship programme: a cross-sectional study of survivors of childhood cancer in Hong Kong.

INTRODUCTION: Lifestyle choices may influence health outcomes in cancer survivors. This study of childhood cancer survivors in Hong Kong investigated factors associated with health-protective and health-damaging behaviours; it also examined expectations of a survivorship programme. METHODS: This cross-sectional study recruited survivors of childhood cancer ≥2 years after treatment. Survivors completed a structured questionnaire to report their health practices and the perceived values of survivorship programme components. Multivariable logistic regression analysis was conducted to identify factors associated with health behaviours. RESULTS: Two hundred survivors were recruited (mean age=23.4 ± 8.8 years; mean duration since treatment, 13.4 ± 7.6 years). Comparatively few survivors exercised ≥4 days/week (16.0%), used sun protection (18.0%), and had a balanced diet (38.5%). Furthermore, comparatively few survivors reported that they had not undergone any immunisation (24.5%) or were unsure (18.5%) about their immunisation history. Most adult survivors were never-drinkers (71.0%) and never-smokers (93.0%). Brain tumour survivors were more likely to have unhealthy eating habits, compared with haematological malignancy survivors (odds ratio [OR]=2.45; 95% confidence interval [CI]=1.29-4.68). Lower socioeconomic status was associated with inadequate sun protection (OR=0.20; 95% CI=0.05-0.83), smoking (OR=5.13; 95% CI=1.48-17.75), and exposure to second-hand smoke (OR=3.52; 95% CI=1.42-8.69). Late-effects screening (78.5%) and psychosocial services to address psychological distress (77%) were considered essential components of a survivorship programme. CONCLUSIONS: Despite the low prevalences of health-damaging behaviours, local survivors of childhood cancer are not engaging in health-protective behaviours. A multidisciplinary programme addressing late effects and psychosocial aspects may address the multifaceted needs of this special population.

Outcomes of adolescents with acute lymphoblastic leukaemia.

INTRODUCTION: Compared with young children who have acute lymphoblastic leukaemia (ALL), adolescents with ALL have unfavourable disease profiles and worse survival. However, limited data are available regarding the characteristics and outcomes of adolescents with ALL who underwent treatment in clinical trials. The aim of this study was to investigate the causes of treatment failure in adolescents with ALL. METHODS: We retrospectively analysed the outcomes of 711 children with ALL, aged 1-18 years, who were enrolled in five clinical trials of paediatric ALL treatment between 1993 and 2015. RESULTS: Among the 711 children with ALL, 530 were young children (1-9 years at diagnosis) and 181 were adolescents (including 136 younger adolescents [10-14 years] and 45 older adolescents [15-18 years]). Compared with young children who had ALL, adolescents with ALL were less likely to have favourable genetic features and more likely to demonstrate poor early response to treatment. The 10-year overall survival and event-free survival rates were significantly lower among adolescents than among young children (77.9% vs 87.6%, P=0.0003; 69.7% vs 76.5%, P=0.0117). There were no significant differences in the 10-year cumulative incidence of relapse, but the 10-year cumulative incidence of treatment-related death (TRD) was significantly greater among adolescents (7.2%) than among young children (2.3%; P=0.002). Multivariable analysis showed that both younger and older adolescents (vs young children) had worse survival and greater incidence of TRD. CONCLUSION: Adolescents with ALL had worse survival because they experienced a greater incidence of TRD. There is a need to investigate optimal treatment adjustments and novel targeted agents to achieve better survival rates (without excessive toxicity) among adolescents with ALL.

Brain death in children: a retrospective review of patients at a paediatric intensive care unit.

PURPOSE: Among patients in paediatric intensive care units (PICUs), death is sometimes inevitable despite advances in treatment. Some PICU patients may have irreversible cessation of all brain function, which is considered as brain death (BD). This study investigated demographic and clinical differences between PICU patients with BD and those with cardiopulmonary death. METHODS: All children who died in the PICU at a university-affiliated trauma centre between October 2002 and October 2018 were included in this retrospective study. Demographics and clinical characteristics were compared between patients with BD and patients with cardiopulmonary death. RESULTS: Of the 2784 patients admitted to the PICU during the study period, 127 died (4.6%). Of these 127 deaths, 22 (17.3%) were BD and 105 were cardiopulmonary death. Length of PICU stay was shorter for patients with cardiopulmonary death than for patients with BD (2 vs 8.5 days, P=0.0042). The most common mechanisms of injury in patients with BD were hypoxic-ischaemic injury (40.9%), central nervous system infection (18.2%), and traumatic brain injury (13.6%). The combined proportion of accident and trauma-related injury was greater in patients with BD than in patients with cardiopulmonary death (27.3% vs 3.8%, P<0.001). Organ donation was approved by the families of four of the 22 patients with BD (18.2%) and was performed successfully in three of these four patients. CONCLUSIONS: These findings emphasise the importance of injury prevention in childhood, as well as the need for education of the public regarding acceptance of BD and support for organ donation.

Direct Observations of Particle Dynamics in Magnetized Collisionless Shock Precursors in Laser-Produced Plasmas.

We present the first laboratory observations of time-resolved electron and ion velocity distributions in magnetized collisionless shock precursors. Thomson scattering of a probe laser beam was used to observe the interaction of a laser-driven, supersonic piston plasma expanding through an ambient plasma in an external magnetic field. From the Thomson-scattered spectra we measure time-resolved profiles of electron density, temperature, and ion flow speed, as well as spatially resolved magnetic fields from proton radiography. We observe direct evidence of the coupling between piston and ambient plasmas, including the acceleration of ambient ions driven by magnetic and pressure gradient electric fields, and deformation of the piston ion flow, key steps in the formation of magnetized collisionless shocks. Even before a shock has fully formed, we observe strong density compressions and electron heating associated with the pileup of piston ions. The results demonstrate that laboratory experiments can probe particle velocity distributions relevant to collisionless shocks, and can complement, and in some cases overcome, the limitations of similar measurements undertaken by spacecraft missions.

Experimental Validation of Low-Z Ion-Stopping Formalisms around the Bragg Peak in High-Energy-Density Plasmas.

We report on the first accurate validation of low-Z ion-stopping formalisms in the regime ranging from low-velocity ion stopping-through the Bragg peak-to high-velocity ion stopping in well-characterized high-energy-density plasmas. These measurements were executed at electron temperatures and number densities in the range of 1.4-2.8 keV and 4×10^{23}-8×10^{23} cm^{-3}, respectively. For these conditions, it is experimentally demonstrated that the Brown-Preston-Singleton formalism provides a better description of the ion stopping than other formalisms around the Bragg peak, except for the ion stopping at v_{i}∼0.3v_{th}, where the Brown-Preston-Singleton formalism significantly underpredicts the observation. It is postulated that the inclusion of nuclear-elastic scattering, and possibly coupled modes of the plasma ions, in the modeling of the ion-ion interaction may explain the discrepancy of ∼20% at this velocity, which would have an impact on our understanding of the alpha energy deposition and heating of the fuel ions, and thus reduce the ignition threshold in an ignition experiment.

Collisionless Shocks Driven by Supersonic Plasma Flows with Self-Generated Magnetic Fields.

Collisionless shocks are ubiquitous in the Universe as a consequence of supersonic plasma flows sweeping through interstellar and intergalactic media. These shocks are the cause of many observed astrophysical phenomena, but details of shock structure and behavior remain controversial because of the lack of ways to study them experimentally. Laboratory experiments reported here, with astrophysically relevant plasma parameters, demonstrate for the first time the formation of a quasiperpendicular magnetized collisionless shock. In the upstream it is fringed by a filamented turbulent region, a rudiment for a secondary Weibel-driven shock. This turbulent structure is found responsible for electron acceleration to energies exceeding the average energy by two orders of magnitude.

Observations of Multiple Nuclear Reaction Histories and Fuel-Ion Species Dynamics in Shock-Driven Inertial Confinement Fusion Implosions.

Fuel-ion species dynamics in hydrodynamiclike shock-driven DT^{3}He-filled inertial confinement fusion implosion is quantitatively assessed for the first time using simultaneously measured D^{3}He and DT reaction histories. These reaction histories are measured with the particle x-ray temporal diagnostic, which captures the relative timing between different nuclear burns with unprecedented precision (∼10 ps). The observed 50±10 ps earlier D^{3}He reaction history timing (relative to DT) cannot be explained by average-ion hydrodynamic simulations and is attributed to fuel-ion species separation between the D, T, and ^{3}He ions during shock convergence and rebound. At the onset of the shock burn, inferred ^{3}He/T fuel ratio in the burn region using the measured reaction histories is much higher as compared to the initial gas-filled ratio. As T and ^{3}He have the same mass but different charge, these results indicate that the charge-to-mass ratio plays an important role in driving fuel-ion species separation during strong shock propagation even for these hydrodynamiclike plasmas.

[A retrospective cohort study of long-term nitrogen dioxide exposure and incident hypertension].

Objective: To investigate the effect of long-term exposure of nitrogen dioxide on the incidence of hypertension. Methods: From March to December 2009, 37 386 eligible residents from four cities in northern China (Tianjin, Shenyang, Taiyuan, and Rizhao) were enrolled in a follow-up study by using the random cluster sampling method. Demographic characteristics, lifestyle, history of diseases, and self-report situation of hypertension were collected by using questionnaire. Based on the average annual concentration of NO2 during the period from the cohort to the onset of hypertension as an estimate of exposure, the effect of NO2 exposure on hypertension was analyzed by employing Cox proportional hazards model. The interactions between NO2 exposure and different characteristics (age, sex, body mass index, smoking, alcohol consumption, education, economy, exercise, and fruit intake) were also examined. Results: The baseline age of residents was (43.74±13.78) years, and the body mass index (BMI) was (22.56±2.92) kg/m(2). During an average follow-up time of 11.40 years, 2 619 (7.0%) new cases of hypertension were reported. The overall mean environmental pollution levels during the study period for the entire cohort was (40.74±17.07) µg/m(3). After adjusting for age, sex, BMI, family history of hypertension, socio-economic information, and lifestyle, the hazard ratio (HR) of incident hypertension with a 10 µg/m(3) increase of NO2 was 1.21 (95%CI: 1.18-1.25). Compared with residents aged 60 years and over (HR=1.19, 95%CI: 1.14-1.26), former and current smoking (HR=1.20, 95%CI: 1.14-1.25), and high-frequency fruit consumption (HR=1.17, 95%CI: 1.13-1.21), residents younger than 60 years (HR=1.28, 95%CI: 1.25-1.32), non-smoker (HR=1.23, 95%CI: 1.19-1.27), and low-frequency fruit consumption (HR=1.27, 95%CI: 1.20-1.35) had stronger interaction effect with NO2 (all P values for interaction<0.05). Conclusion: NO2 exposure may lead to the onset of hypertension, which has a stronger effect on people younger than 60 years old, without smoking history and with low-frequency fruit consumption.

[Clinical analysis of ankle arthroscopy technique for treatment of tarsal tunnel syndrome].

Objective: To explore the effects of ankle arthroscopy technique in treating the tarsal tunnel syndrome. Methods: From May 2014 to May 2016, the ankle arthroscopy technique was used for surgical treatment of tarsal tunnel syndrome in the Department of Hand and Foot Microsurgery in Xuzhou Central Hospital. Twenty-two patients with 24 feet with tarsal tunnel syndrome were hospitalized for treatment, with 10 left feet and 14 right feet, aged 26-57 years. The disease duration ranged from 4 to 15 months (mean 8.3 months). The dual-portals ankle arthroscopic neurolysis and fiber membrane resection were performed. The Pfeiffer scoring system was used to evaluate the post-operative outcomes. Results: Primarily healing of the wound was achieved in all the patients. No postoperative infection was found during the follow-up. The postoperative hospitalization time was 2 to 5 days (mean 3.7 days). All patients were followed up for 12 to 24 months. At the final follow-up, all the patients had significant improvement in numbness and pain. According to the Pfeiffer scoring system, the results were excellent in 16 feet, good in 8 feet, with an excellent and good rate of 100%. Conclusion: The ankle arthroscopic neurolysis is a safe and easy treatment option for the tarsal tunnel syndrome and provides satisfactory results.

Proton Spectra from

Few-body nuclear physics often relies upon phenomenological models, with new efforts at the ab initio theory reported recently; both need high-quality benchmark data, particularly at low center-of-mass energies. We use high-energy-density plasmas to measure the proton spectra from ^{3}He+T and ^{3}He+^{3}He fusion. The data disagree with R-matrix predictions constrained by neutron spectra from T+T fusion. We present a new analysis of the ^{3}He+^{3}He proton spectrum; these benchmarked spectral shapes should be used for interpreting low-resolution data, such as solar fusion cross-section measurements.

Transition from Collisional to Collisionless Regimes in Interpenetrating Plasma Flows on the National Ignition Facility.

A study of the transition from collisional to collisionless plasma flows has been carried out at the National Ignition Facility using high Mach number (M>4) counterstreaming plasmas. In these experiments, CD-CD and CD-CH planar foils separated by 6-10 mm are irradiated with laser energies of 250 kJ per foil, generating ∼1000 km/s plasma flows. Varying the foil separation distance scales the ion density and average bulk velocity and, therefore, the ion-ion Coulomb mean free path, at the interaction region at the midplane. The characteristics of the flow interaction have been inferred from the neutrons and protons generated by deuteron-deuteron interactions and by x-ray emission from the hot, interpenetrating, and interacting plasmas. A localized burst of neutrons and bright x-ray emission near the midpoint of the counterstreaming flows was observed, suggesting strong heating and the initial stages of shock formation. As the separation of the CD-CH foils increases we observe enhanced neutron production compared to particle-in-cell simulations that include Coulomb collisions, but do not include collective collisionless plasma instabilities. The observed plasma heating and enhanced neutron production is consistent with the initial stages of collisionless shock formation, mediated by the Weibel filamentation instability.