Diverse polarization angle swings from a repeating fast radio burst source.

Fast radio bursts (FRBs) are millisecond-duration radio transients1,2 of unknown origin. Two possible mechanisms that could generate extremely coherent emission from FRBs invoke neutron star magnetospheres3-5 or relativistic shocks far from the central energy source6-8. Detailed polarization observations may help us to understand the emission mechanism. However, the available FRB polarization data have been perplexing, because they show a host of polarimetric properties, including either a constant polarization angle during each burst for some repeaters9,10 or variable polarization angles in some other apparently one-off events11,12. Here we report observations of 15 bursts from FRB 180301 and find various polarization angle swings in seven of them. The diversity of the polarization angle features of these bursts is consistent with a magnetospheric origin of the radio emission, and disfavours the radiation models invoking relativistic shocks.

Search for Spin-Dependent Gravitational Interactions at Earth Range.

Among the four fundamental forces, only gravity does not couple to particle spins according to the general theory of relativity. We test this principle by searching for an anomalous scalar coupling between the neutron spin and the Earth's gravity on the ground. We develop an atomic gas comagnetometer to measure the ratio of nuclear spin-precession frequencies between ^{129}Xe and ^{131}Xe, and search for a change of this ratio to the precision of 10^{-9} as the sensor is flipped in Earth's gravitational field. The null results of this search set an upper limit on the coupling energy between the neutron spin and the gravity on the ground at 5.3×10^{-22} eV (95% confidence level), resulting in a 17-fold improvement over the previous limit. The results can also be used to constrain several other anomalous interactions. In particular, the limit on the coupling strength of axion-mediated monopole-dipole interactions at the range of Earth's radius is improved by a factor of 17.

Insomnia and multiple health outcomes: umbrella review of meta-analyses of prospective cohort studies.

OBJECTIVES: To evaluate existing evidence of prospective cohort studies on associations between insomnia and multiple health outcomes. STUDY DESIGN: An umbrella review of meta-analyses of prospective cohort studies. METHODS: A systematic search was undertaken in Pubmed, Embase, Cochrane, and Web of Science from inception to October 2021 to find meta-analyses of prospective cohort studies investigating the association of insomnia with any health outcome. The summary relative risk (SRR) for each meta-analysis was recalculated with random-effects model. The methodological quality and the quality of evidence were assessed by the A Measurement Tool to Assess Systematic Reviews and Grading of Recommendations, Assessment, Development and Evaluation, respectively. RESULTS: A total of 25 published meta-analyses of prospective cohort studies, reporting 63 SRRs for 29 unique outcomes were included. Insomnia was mainly related to cardiovascular outcomes and mental disorders. The former comprised atrial fibrillation (SRR: 1.30, 95% confidence interval: 1.26 to 1.35), cardiovascular diseases (1.45, 1.29 to 1.64), coronary heart disease (1.28, 1.10 to 1.50), myocardial infarction (1.42, 1.17 to 1.72), and stroke (1.55, 1.39 to 1.72). The latter involved alcohol abuse (1.35, 1.08 to 1.67), all mental disorders (2.16, 1.70 to 3.97), anxiety (3.23, 1.52 to 6.85), depression (2.31, 1.90 to 2.81), suicidal ideation (2.26, 1.79 to 2.86), suicidal attempt (1.99, 1.31 to 3.02), and suicidal death (1.72, 1.42 to 2.08). Besides, insomnia enhanced the risk of Alzheimer's disease (1.51, 1.06 to 2.14) and hyperlipidemia (1.64, 1.53 to 1.76). CONCLUSION: Insomnia exhibits considerable adverse outcomes, primarily comprises cardiovascular outcomes and mental disorders, but further studies with robustly designed trials are needed to draw firmer conclusions.

[A preliminary study on the prevention of hemorrhage after laparoscopic pancreaticoduodenectomy by wrapping gastroduodenal artery stump in the left external liver lobe and the left caudate lobe].

Objective: To investigate the safety and efficacy of embedding the stump of gastroduodenal artery between the left lateral lobe of the liver and the left caudate lobe to prevent bleeding after laparoscopic pancreaticoduodenectomy. Methods: The clinical data of 41 patients who underwent laparoscopic pancreaticoduodenectomy at the second Hospital of Hebei Medical University from October 2021 to April 2022 were analyzed retrospectively.There were 27 males and 14 females, aged (63.0±9.2)years (range: 48 to 78 years), and the body mass index was (24.1±3.2)kg/m2 (range: 15.4 to 31.6 kg/m2). After routine laparoscopic pancreaticoduodenectomy, the stump of gastroduodenal artery was embedded between the left lateral lobe and the left caudate lobe of the liver, and the hepatic parenchyma of the left lateral lobe and the left caudate lobe were sutured with absorbable sutures.The occurrence and recovery of postoperative complications (pancreatic fistula, biliary fistula, postoperative abdominal bleeding, abdominal infection, liver abscess) were observed. Results: All the operations of 41 patients were completed successfully.The operation time was (277.5±52.0) minutes (range: 192 to 360 minutes). The entrapment time of gastroduodenal artery stump was (3.1±0.6) minutes (range: 2.3 to 4.2 minutes), and the intraoperative blood loss (M(IQR)) was 300 (200) ml (range: 50 to 800 ml).The results of ultrasound examination of hepatic artery on the first day after operation showed that the blood flows of hepatic artery were unobstructed.Postoperative pancreatic fistula occurred in 3 cases, including grade B pancreatic fistula in 2 cases (1 case with abdominal infection) and biochemical leakage in 1 case. Three patients with pancreatic fistula were discharged successfully after continuous abdominal drainage. There was no biliary fistula, abdominal bleeding, abdominal infection, liver abscess or postoperative liver dysfunction. Conclusion: The encasement of the gastroduodenal artery stump by the left outer and left caudate lobes of the liver may be an effective way to prevent bleeding from the rupture of the gastroduodenal artery stump after laparoscopic pancreatoduodenectomy, which is easy and safe to perform.

Search for Monopole-Dipole Interactions at the Submillimeter Range with a

Monopole-dipole interactions involving scalar couplings between a spin and a massive particle violate both P and T symmetry, and can be mediated by axions. We use a ^{129}Xe-^{131}Xe-Rb atomic cell comagnetometer to measure the ratio of precession frequencies between the two xenon isotopes, and search for changes of the ratio correlated with the distance between the atomic cell and a nonmagnetic bismuth germanate crystal. A modulated Rb polarization scheme is used to suppress systematic effects by 2 orders of magnitude. The null results of this search improve the upper limit on the coupling strength g_{s}^{N}g_{p}^{n} over the interaction range 0.11-0.55 mm, and by a maximum improvement factor of 30 at 0.24 mm. The corresponding propagator mass range of this new excluded region covers 0.36-1.80 meV.

Vitamin D inadequacy combined with high BMI affects paraspinal muscle atrophy and pain intensity in postmenopausal women.

OBJECTIVE: This study was performed to assess the effects of vitamin D deficiency/insufficiency combined with a high body mass index (BMI) on paraspinal muscle (PSM) atrophy and pain intensity in postmenopausal women with lower back pain (LBP). METHODS: In total, 365 postmenopausal women were analyzed in the study. We divided the women into four groups according to BMI and vitamin D status. Outcome measurements included PSM atrophy, fatty infiltration (FI) and severity of LBP. Binary logistic regression was used to analyze the odds ratio (OR), and the interaction between the BMI and vitamin D status was tested. RESULTS: Compared with the control group, the high BMI with vitamin D deficiency/insufficiency group had a significantly increased risk of FI > grade 2 (OR = 10.69, p < 0.001), hand grip strength of <16 kg (OR = 8.96, p < 0.001), Short Physical Performance Battery score of ≤8 (OR = 3.69, p < 0.001) and visual analog scale (VAS) score of >3 (OR = 4.76, p < 0.001). A significant positive additive interaction was found between the BMI and vitamin D status on PSM atrophy. CONCLUSION: Vitamin D deficiency/insufficiency combined with a high BMI was associated with PSM atrophy and LBP intensity in postmenopausal women. The interaction analysis showed a positive additive interaction between BMI and vitamin D status.

Antifungal activity of puroindoline protein from soft wheat against grain molds and its potential as a biocontrol agent.

Mold growth reduces the quality of stored grains, besides producing toxins that pose a potential threat to human health. Therefore, prevention of grain mold growth during storage is important to ensure a safe and high-quality product, preferably using an eco-friendly antifungal agent. The puroindoline (PIN) protein was extracted by Triton X-114 and identified by QE mass spectrometry. Aspergillus flavus has attracted much attention because of its toxic secondary metabolites, and PIN protein showed a significant inhibition on A. flavus growth. Scanning electron microscopy revealed altered spore morphology of A. flavus following PIN protein treatment, and propidium iodide staining showed incomplete spore cell membranes. The disruption and deformation of A. flavus spores suggest that the cell walls and cell membranes were compromised. Decreased mitochondrial membrane potential and increased levels of intracellular reactive oxygen specieswere detected using JC-1 and 2,7-dichlorodihydrofluorescein diacetate staining, respectively. PIN protein could effectively inhibit the growth and aflatoxins B1 production of A. flavus in stored grains, such as wheat and rice. PIN proteins can inhibit the growth of many common grain storage molds, including Penicillium, Aspergillus spp. (A. flavus, A. glaucus, A. kawachii, A. ochraceus and A. niger), Alternaria and Fusarium graminearum, in a dose-dependent manner. PIN protein has a significant inhibitory effect on the growth of grain molds, with a stronger inhibitory effect noted in wheat and rice. Our study provides a novel and simple theoretical basis for the selection and storage of mold resistance in grains and food during storage.

[Consideration on implementation of co-administration of Seasonal Influenza and COVID-19 vaccines during pandemic in China].

Influenza is an infectious respiratory disease caused by the influenza viruses. Older people, infants and people with underlying medical conditions could have a higher risk of severe influenza symptoms and complications. The co-infection of Coronavirus Diseases 2019 (COVID-19) with influenza viruses could lead to the complication of prevention, diagnosis, control, treatment, and recovery of COVID-19. Influenza vaccine and COVID-19 vaccine overlapped in target populations, vaccination time, and inoculation units. Although there was insufficient evidence on the immunogenicity and safety of co-administration of influenza vaccine and COVID-19 vaccine, World Health Organization and some countries recommended co-administration of inactivated influenza vaccine and COVID-19 vaccine. This review summarized domestic and international vaccination policies and research progress, and put forward corresponding suggestions in order to provide scientific support for the formulation of vaccination strategy on seasonal influenza vaccine and COVID-19 vaccine.

[Analysis of transmission characteristics of COVID-19 in Shaanxi Province].

A total of 245 cases of COVID-19 in Shaanxi Province reported in the China information system for disease control and prevention as of February 24, 2020 were selected as the research objects, the cases are divided into imported cases (116 cases, 47.3%) and local cases (129 cases, 52.7%), their basic characteristics, time distribution, transmission mode, intergenerational interval and latent period transmission are analyzed. The age of local cases [(51.74±15.67) years old], female patients (69 cases, 53.5%), housework and retired staff (40 cases, 31.0%), and patients isolated at the time of onset (50 cases, 38.8%) were higher than imported cases, respectively[(40.66±15.41) years old, (45 cases, 38.8%), (21 cases, 18.1%), (17 cases, 14.6%)] (P values were < 0.05); The infection rate was 0.8% (31/3 666) in close contacts with local cases, which was lower than imported cases 2.0% (69/3 435) (P<0.001); The main source of infection in local cases was relatives (70 cases, 54.3%), and the main way of infection was living together and party (90 cases, 69.8%); the proportion of latent period transmission in our province was 15.5% (20 cases), and the interval between the second-generation case and the source of infection was about 4 days, and the interval between generations was about 6 days. In summary, the main way of infection of local cases in Shaanxi Province was living together and party, there were a certain proportion of latent period transmission cases at present, it's suggested that the investigation of close contacts should be started 4 days or earlier before the onset of the case.

[Application and status of digestive endoscopy in the overall management of portal hypertension-related esophagogastric variceal bleeding].

Portal hypertension-related esophagogastric variceal bleeding (EVB) is deadly. Therefore, multidisciplinary management involving hepatologists, digestive endoscopy, radiological intervention, and/or surgery is necessary. Digestive endoscopy is the core of the multidisciplinary approach to the overall management of portal hypertension. It plays an important role in the early warning, emergency treatment, and the prevention of the initial and re-bleeding of portal hypertension accompanied by esophagogastric varices. In addition, gastroscopy with endoscopic ultrasound scanning can enhance the management capabilities of ectopic varices.

Traditional Semiconductors in the Two-Dimensional Limit.

Interest in two-dimensional materials has exploded in recent years. Not only are they studied due to their novel electronic properties, such as the emergent Dirac fermion in graphene, but also as a new paradigm in which stacking layers of distinct two-dimensional materials may enable different functionality or devices. Here, through first-principles theory, we reveal a large new class of two-dimensional materials which are derived from traditional III-V, II-VI, and I-VII semiconductors. It is found that in the ultrathin limit the great majority of traditional binary semiconductors studied (a series of 28 semiconductors) are not only kinetically stable in a two-dimensional double layer honeycomb structure, but more energetically stable than the truncated wurtzite or zinc-blende structures associated with three dimensional bulk. These findings both greatly increase the landscape of two-dimensional materials and also demonstrate that in the double layer honeycomb form, even ordinary semiconductors, such as GaAs, can exhibit exotic topological properties.

Effect of Hartree-Fock pseudopotentials on local density functional theory calculations.

Density functional theory (DFT) can run into serious difficulties with localized states in elements such as transition metals with occupied d states and oxygen. In contrast, including a fraction of the Hartree-Fock exchange can be a better approach for such localized states. Here, we develop Hartree-Fock pseudopotentials to be used alongside DFT for solids. The computational cost is on a par with standard DFT. Calculations for a range of II-VI, III-V and group-IV semiconductors with diverse physical properties show an observably improved band gap for systems containing d-electrons, pointing to a new direction in electronic theory.

Graphene cover-promoted metal-catalyzed reactions.

Graphitic overlayers on metals have commonly been considered as inhibitors for surface reactions due to their chemical inertness and physical blockage of surface active sites. In this work, however, we find that surface reactions, for instance, CO adsorption/desorption and CO oxidation, can take place on Pt(111) surface covered by monolayer graphene sheets. Surface science measurements combined with density functional calculations show that the graphene overlayer weakens the strong interaction between CO and Pt and, consequently, facilitates the CO oxidation with lower apparent activation energy. These results suggest that interfaces between graphitic overlayers and metal surfaces act as 2D confined nanoreactors, in which catalytic reactions are promoted. The finding contrasts with the conventional knowledge that graphitic carbon poisons a catalyst surface but opens up an avenue to enhance catalytic performance through coating of metal catalysts with controlled graphitic covers.

[Quality of case report of Japanese Encephalitis after the establishment of surveillance on acute meningitis and encephalitis syndrome in Baoji].

Objective: To evaluate the quality of Japanese Encephalitis (JE) case reports based on the establishment of surveillance on acute meningitis and encephalitis syndrome (AMES) in Baoji. Methods: A surveillance network on AMES cases was set up in Baoji city of Shaanxi province between July 2013 and December 2016. All the cases met the surveillance definition of AMES cases were conducted a questionnaire, collected serum and/or cerebrospinal fluid (CSF) specimens to test JE immunoglobulin M antibodies by using enzyme-linkedimmunosorbent assay methods.The information of the incidence of JE in Shaanxi and Baoji from 2009 to 2016 originated from the China information system for disease control and prevention. Chi square test was used to compare the difference in JE incidence in Baoji, Shaanxi before and after the implementation of AMES monitoring project. Results: 75 out of 855 collected cases were laboratory confirmed as JE, Including 42 suspected JE cases and 33 other suspected cases diagnosed after hospitalization. Except 1 case occurring in December, all the other cases occurred between July and October, especially in August with a peak of 55 cases (73.3%), and 6 cases (8.0%) in July, 11 cases (14.7%) in September, 2 cases (2.7%) in October. The proportion of patients aging 0-6, 7-14 and ≥15 years old were respectively 4.0% (3 cases), 8.0% (6 cases) and 88.0% (66 cases). The biochemical test showed the cerebrospinal fluid in 13 cases (17.3%) were slightly turbid, the white blood cell in 31 cases (41.3%) elevated, the glucose levels in 24 cases (32.0%) were abnormal, and the chloride level in 23 cases (30.7%) were abnormal. A total of 103 cases of JE were diagnosed in Baoji from 2009 to 2016, with an average annual incidence rate at 0.34/100 000. The average incidence of JE in 2009-2012 and 2013-2016 was 0.21/100 000 and 0.48/100 000 respectively. From 2013 to 2016, the proportion of JE cases in Baoji, Shaanxi was 19.3% (71/369), and it was 8.9% (32/362) between 2009 and 2012 (χ(2)=4.15, P=0.040). Conclusion: The AMES surveillance project improved the quality of the JE case report in Baoji. Changes appeared in biochemistrical and epidemiological characteristics of cerebrospinal fluid. The incidence of JE was seriously underestimated in Shaanxi province and therefore the sensitivity of Japanese encephalitis surveillance cases should be further improved.

Carrier-Multiplication-Induced Structural Change during Ultrafast Carrier Relaxation and Nonthermal Phase Transition in Semiconductors.

While being extensively studied as an important physical process to alter exciton population in nanostructures at the fs time scale, carrier multiplication has not been considered seriously as a major mechanism for phase transition. Real-time time-dependent density functional theory study of Ge_{2}Sb_{2}Te_{5} reveals that carrier multiplication can induce an ultrafast phase transition in the solid state despite that the lattice remains cold. The results also unify the experimental findings in other semiconductors for which the explanation remains to be the 30-year old phenomenological plasma annealing model.

Toward the Intrinsic Limit of the Topological Insulator Bi_{2}Se_{3}.

Combining high resolution scanning tunneling microscopy and first principles calculations, we identified the major native defects, in particular the Se vacancies and Se interstitial defects, that are responsible for the bulk conduction and nanoscale potential fluctuations in single crystals of archetypal topological insulator Bi_{2}Se_{3}. Here it is established that the defect concentrations in Bi_{2}Se_{3} are far above the thermodynamic limit, and that the growth kinetics dominate the observed defect concentrations. Furthermore, through careful control of the synthesis, our tunneling spectroscopy suggests that our best samples are approaching the intrinsic limit with the Fermi level inside the band gap without introducing extrinsic dopants.

High-Temperature Quantum Anomalous Hall Effect in n-p Codoped Topological Insulators.

The quantum anomalous Hall effect (QAHE) is a fundamental quantum transport phenomenon that manifests as a quantized transverse conductance in response to a longitudinally applied electric field in the absence of an external magnetic field, and it promises to have immense application potential in future dissipationless quantum electronics. Here, we present a novel kinetic pathway to realize the QAHE at high temperatures by n-p codoping of three-dimensional topological insulators. We provide a proof-of-principle numerical demonstration of this approach using vanadium-iodine (V-I) codoped Sb_{2}Te_{3} and demonstrate that, strikingly, even at low concentrations of ∼2% V and ∼1% I, the system exhibits a quantized Hall conductance, the telltale hallmark of QAHE, at temperatures of at least ∼50 K, which is 3 orders of magnitude higher than the typical temperatures at which it has been realized to date. The underlying physical factor enabling this dramatic improvement is tied to the largely preserved intrinsic band gap of the host system upon compensated n-p codoping. The proposed approach is conceptually general and may shed new light in experimental realization of high-temperature QAHE.

Regulating energy transfer of excited carriers and the case for excitation-induced hydrogen dissociation on hydrogenated graphene.

Understanding and controlling of excited carrier dynamics is of fundamental and practical importance, particularly in photochemistry and solar energy applications. However, theory of energy relaxation of excited carriers is still in its early stage. Here, using ab initio molecular dynamics (MD) coupled with time-dependent density functional theory, we show a coverage-dependent energy transfer of photoexcited carriers in hydrogenated graphene, giving rise to distinctively different ion dynamics. Graphene with sparsely populated H is difficult to dissociate due to inefficient transfer of the excitation energy into kinetic energy of the H. In contrast, H can easily desorb from fully hydrogenated graphane. The key is to bring down the H antibonding state to the conduction band minimum as the band gap increases. These results can be contrasted to those of standard ground-state MD that predict H in the sparse case should be much less stable than that in fully hydrogenated graphane. Our findings thus signify the importance of carrying out explicit electronic dynamics in excited-state simulations.

Determination of formation and ionization energies of charged defects in two-dimensional materials.

We present a simple and efficient approach to evaluate the formation energy and, in particular, the ionization energy (IE) of charged defects in two-dimensional (2D) systems using the supercell approximation. So far, first-principles results for such systems can scatter widely due to the divergence of the Coulomb energy with vacuum dimension, denoted here as L_{z}. Numerous attempts have been made in the past to fix the problem under various approximations. Here, we show that the problem can be resolved without any such assumption, and a converged IE can be obtained by an extrapolation of the asymptotic IE expression at large L_{z} (with a fixed lateral area S) back to the value at L_{z}=0. Application to defects in monolayer boron nitride reveal that defects in 2D systems can be unexpectedly deep, much deeper than the bulk.

A low-surface energy carbon allotrope: the case for bcc-C6.

Graphite may be viewed as a low-surface-energy carbon allotrope with little layer-layer interaction. Other low-surface-energy allotropes but with much stronger layer-layer interaction may also exist. Here, we report a first-principles prediction for one of the known carbon allotropes, bcc-C6 (a body centered carbon allotrope with six atoms per primitive unit), that should have exceptionally low-surface energy and little size dependence down to only a couple layer thickness. This unique property may explain the existence of the relatively-high-energy bcc-C6 during growth. The electronic properties of the bcc-C6 thin layers can also be intriguing: the (111), (110), and (001) thin layers have direct band gap, indirect band gap, and metallic character, respectively. The refrained chemical reactivity of the thin layers does not disappear after cleaving, as lithium-doped (Li-doped) 3-layers (111) has a noticeably increased binding energy of H2 molecules with a maximum storage capacity of 10.8 wt%.