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.

[Outcomes after surgical repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries: a series of 104 cases]

Objective: To examine the early and midterm surgical outcome of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA/VSD/MAPCA) using revised surgical strategies. Methods: A retrospective analysis of clinical data, surgical methods, and follow-up results was performed of 104 cases of PA/VSD/MAPCA in Department of Cardiovascular Surgery, Guangzhou Women and Children's Medical Center from January 2017 to September 2022. There were 55 males and 49 females, aged (M(IQR)) 33.9(84.0) months (range: 0.5 to 209.6 months) at the first surgical procedures. The anatomical classification included 89 cases of type B and 15 cases of type C. The number of major aortopulmonary collateral arteries was 4.2 (3.0) (range: 1 to 8). The Kaplan-Meier method was used for survival estimation. Results: In the first stage of surgery, 50 patients underwent a complete primary repair, 12 patients underwent partial repair, 32 patients underwent palliative right ventricular-pulmonary artery connection, and only 10 patients chose the Blalock-Taussig shunt. There were 10 cases of early death. In the second stage, 14 patients underwent complete repair and 4 patients underwent partial repair with no early death. The interval between the two surgeries was 19 (10) months (range: 9 to 48 months). Finally, during the 40 (34) months follow-up period, a total of 64 patients were complete repair and the right/left ventricular pressure ratio after complete repair was 0.63±0.16 (range: 0.36 to 1.00). Survival analysis showed that survival rates at 1 and 5 years after first-stage surgery were both 89.4% (95%CI: 83.5% to 95.3%). At 28 (34) months (range: 1 to 67 months) of follow-up after complete repair, the survival analysis showed that the survival rates at 1 and 5 years were both 95.2% (95%CI: 89.9% to 100%). Conclusions: Using combined approaches tailored to individual patients and optimized unifocalization strategy, the complete repair rate at one stage and the cumulative complete repair rate at 5 years improved significantly with a lower right/left ventricular pressure ratio and satisfactory early and intermediate survival.

[Study on the comparison of postoperative liver injury caused by hepatic arterial perfusion chemotherapy combined with targeted immunotherapy with hepatic arterial chemoembolization combined with targeted immunotherapy for intermediate-and advanced-stage liver cancer]

Objective: To compare the postoperative liver function injury condition in patients with intermediate-and advanced-stage hepatocellular carcinoma (HCC) treated with hepatic artery infusion chemotherapy (HAIC) and hepatic artery chemoembolization (TACE) combined with immune checkpoint inhibitors (ICIs) and multi-target tyrosine kinase inhibitors (TKIs). Methods: Patients with intermediate-and advanced-stage HCC who were admitted and treated with HAIC/TACE+ICIs+TKIs therapy at Nanfang Hospital of Southern Medical University from January 2019 to November 2021, with follow-up up to July 2023, were retrospectively enrolled. The results of liver function tests within one week before interventional surgery and on the first day after surgery were recorded. The degree of postoperative liver injury was graded according to the common terminology criteria for adverse events 5.0 (CTCAE 5.0). The treatment efficacy was evaluated according to RECIST 1.1 criteria. Measurement data were compared between groups using a t-test or a non-parametric rank sum test. Enumeration data were compared between the groups using the χ(2) test or Fisher's exact probability method. The survival condition differences were analyzed by the log-rank method. Results: This study included 82 and 77 cases in the HAIC and TACE groups. There were no statistically significant differences between the two groups of patients in terms of gender, age, physical condition score, number of tumors, presence or absence of liver cirrhosis, Child-Pugh grade, albumin-bilirubin (ALBI) grade, and combined ICIs and TKIs . The HAIC group had later tumor staging, a greater tumor burden, poorer liver reserve function, and a larger proportion of patients in stage C (81.7% vs. 63.6%), χ(2)=6.573, P = 0.01). There were 53 cases (64.6% vs. 32.5%) with a maximum tumor diameter of ≥ 10cm, χ(2)=16.441, P < 0.001), and more patients had a retention rate of ≥ 10% for indocyanine green (ICG) at 15 minutes (68.3% vs. 51.9%, P = 0.035). The postoperative incidence rate of increased levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin was significantly lower in the HAIC group than that in the TACE group (28.0% vs. 63.6%, χ(2)=20.298, P < 0.001, 54.9% vs. 85.7%, χ(2)=17.917, P < 0.001;40.2% vs. 55.8%, χ(2)=3.873, P = 0.049). The number of patients with postoperative ALBI grade 3 was significantly lower in the HAIC group than that in the TACE group (6.1% vs. 16.9%, χ(2)=4.601, P = 0.032). There was no statistically significant difference in the incidence rate of postoperative hypoalbuminemia, activated partial thromboplastin time, or increased international standardized ratio between the two groups of patients. There was no statistically significant difference in median progression-free survival (7.3 months vs. 8.2 months, P = 0.296) or median overall survival (16.5 months vs. 21.9 months, P = 0.678) between the two groups of patients. Conclusion: The incidence rate of postoperative liver injury is higher in patients with intermediate-and advanced-stage HCC treated with TACE combined with ICIs and TKIs than in patients with HAIC combined with ICIs and TKIs.

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.

Greater transferability and accuracy of norm-conserving pseudopotentials using nonlinear core corrections

We present an investigation into the transferability of pseudopotentials (PPs) with a nonlinear core correction (NLCC) using the Goedecker, Teter, and Hutter (GTH) protocol across a range of pure GGA, meta-GGA and hybrid functionals, and their impact on thermochemical and non-thermochemical properties. The GTH-NLCC PP for the PBE density functional demonstrates remarkable transferability to the PBE0 and ωB97X-V exchange-correlation functionals, and relative to no NLCC, improves agreement significantly for thermochemical benchmarks compared to all-electron calculations. On the other hand, the B97M-rV meta-GGA functional performs poorly with the PBE-derived GTH-NLCC PP, which is mitigated by reoptimizing the NLCC parameters for this specific functional. The findings reveal that atomization energies exhibit the greatest improvements from use of the NLCC, which thus provides an important correction needed for covalent interactions relevant to applications involving chemical reactivity. Finally we test the NLCC-GTH PPs when combined with medium-size TZV2P molecularly optimized (MOLOPT) basis sets which are typically utilized in condensed phase simulations, and show that they lead to consistently good results when compared to all-electron calculations for atomization energies, ionization potentials, barrier heights, and non-covalent interactions, but lead to somewhat larger errors for electron affinities.

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.

Emergent Majorana zero-modes in an intrinsic anti-ferromagnetic topological superconductor Mn2B2 monolayer

Topological superconductors (TSCs) are an exotic field due to the existence of Majorana zero-modes (MZM) in the edge states that obey non-Abelian statistics and can be used to implement topological quantum computations, especially for two-dimensional (2D) materials. Here we predict manganese diboride (Mn₂B₂) as an intrinsic 2D anti-ferromagnetic (AFM) TSC based on the magnetic and electronic structures of Mn and B atoms. Once Mn₂B₂ ML enters a superconducting state, MZM will be induced by the spin-polarized helical gapless edge states. The Z₂ topological non-trivial properties are confirmed by Wannier charge centers (WCC) and the platform of the spin Hall conductivity near the Fermi level. Phonon-electron coupling (EPC) implies s-wave superconductivity and the critical temperature (T_c) is 6.79 K.

[Exploration of phase angle used to construct PG-SGA nutritional assessment and prediction model for malignant tumor patients]

Objective: To explore the value of phase angle (PA) in constructing a predictive model of nutrition evaluation for tumor patients. Methods: A retrospective analysis was performed on 1 129 patients with malignant tumors hospitalized in the Cancer Center of Changzhi People's Hospital from June 2020 to February 2021. PA values of six parts of the body were measured by the body composition analyzer, including: left arm (LA), right arm (RA), left leg (LL), right leg (RL), the trunk (TR), and the whole body (WB). Patients' body mass index (BMI) was calculated and patient-generated subjective global assessment (PG-SGA) was assessed. The differences of PA values of six parts were compared and their correlations with BMI and PG-SGA in combination with age, gender and tumor disease types were analyzed, binary classification regression on BMI and PG-SGA was performed, and the functions of the best prediction model was fitted. Decision tree, random forest, Akaike information criterion in a Stepwise Algorithm (stepAIC) and generalized likelihood ratio test were used to select appropriate variables, and the logit logistic regression model was used to fit the data. Results: Comparing the PA values of six parts in pairs, it was found that the PA values of LA and RA, LL and RL, and TR and WB were linearly correlated and the coefficient was close to 1 (P<0.001). Binary classification regression was performed for BMI and PG-SGA, respectively. In order to make the data have clinical significance, 18.5 kg/m(2) was used as the classification point for BMI, 4 and 9 were used as the classification points for PG-SGA score, and the models of A, B and C were obtained. Suitable variables including PA-LA, PA-TR and tumor disease types were used as variables to fit BMI classification; BMI, PA-LA and age were used as variables to fit the PG-SGA model with 9 as the classification point. PA-LA, PA-TR, BMI, age and tumor disease types were used as variables to fit the PG-SGA model with 4 as the classification point. In this study, the predicted values of models A, B and C obtained by R-studio were imported into SPSS 26.0 software, and the cut-off values of classification were obtained by the receiver operating characteristic (ROC) curve. The ROC analytic results showed that the best cut-off values of Model A, B and C were 0.155, 0.793 and 0.295. Model A recommended when the probability is >0.155, a patient's nutritiond tatus should be classified as BMI < 18.5 kg/m(2) group. Model B recommended that PG-SGA<9 group be classified as the probability is >0.793. Model C recommended that PG-SGA < 4 group should be classified when probability is >0.295. Conclusions: The PG-SGA classification prediction model is simple to operate, and the nutritional status of patients can be roughly divided into three groups: normal or suspected malnutrition group (PG-SGA<4), moderate malnutrition group (4≤PG-SGA<9), and severe malnutrition group (PG-SGA≥9). This model can more efficiently predict the nutritional status of cancer patients, greatly simplify the nutritional assessment process, and better guide the standardized treatment of clinical malnutrition.

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.

AuB8-: an Au-borozene complex

Photoelectron spectroscopy and quantum chemistry studies are used to investigate the structure and bonding of AuB₈^-. Global minimum sturctural searches show that AuB₈^- possesses a chair-like structure, which can be viewed as Au⁺ bonded to the edge of the doubly-aromatic B₈^2- borozene, Au⁺[η²-B₈^2-]. Chemical bonding analyses reveal that the AuB₈^- is a novel borozene complex with unique Au-borozene bonding.

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.

The smallest 4f-metalla-aromatic molecule of cyclo-PrB2− with Pr–B multiple bonds

The concept of metalla-aromaticity proposed by Thorn–Hoffmann (Nouv. J. Chim. 1979, 3, 39) has been expanded to organometallic molecules of transition metals that have more than one independent electron-delocalized system. Lanthanides, with highly contracted 4f atomic orbitals, are rarely found in multiply aromatic systems. Here we report the discovery of a doubly aromatic triatomic lanthanide-boron molecule PrB₂⁻ based on a joint photoelectron spectroscopy and quantum chemical investigation. Global minimum structural searches reveal that PrB₂⁻ has a C_2v triangular structure with a paramagnetic triplet ³B₂ electronic ground state, which can be viewed as featuring a trivalent Pr(III,f²) and B₂⁴⁻. Chemical bonding analyses show that this cyclo-PrB₂⁻ species is the smallest 4f-metalla-aromatic system exhibiting σ and π double aromaticity and multiple Pr–B bonding characters. It also sheds light on the formation of the rare B₂⁴⁻ tetraanion by the high-lying 5d orbitals of the 4f-elements, completing the isoelectronic B₂⁴⁻, C₂²⁻, N₂, and O₂²⁺ series.

We report the smallest 4f-metalla-aromatic molecule of PrB₂⁻ exhibiting σ and π double aromaticity and multiple Pr–B bond characters.

Linear Combination of Atomic Dipoles to Calculate the Bond and Molecular Dipole Moments of Molecules and Molecular Liquids

We report a linear combination of atomic dipole (LCAD) method for calculating the bond dipole moments of molecules. We show that the LCAD method reproduces the known molecular dipole moments of small to large molecules with a small error with respect to experimental and benchmark ab initio calculations, and molecular dipole distributions of bulk water that agree with maximally localized Wannier functions. The bond dipole moments derived from LCAD are also chemically interpretable in terms of the trend in bond ionicity in going from neutral to charged molecules. Moreover, the LCAD method accurately captures the influence of electric fields, supported by the correct trend in the change of the dipole moment under a uniform external electric field. The better grounding of bond dipole calculations indicates that it should also serve as a useful approach to bond dipole-field models used in catalysis or to reconstruct the small dipole of a H-terminated graphene flake.

Optimized Pseudopotentials and Basis Sets for Semiempirical Density Functional Theory for Electrocatalysis Applications

A complete set of Goedecker, Teter, and Hutter (GTH) norm-conserving pseudopotentials (PPs) have been optimized, in conjunction with molecular optimized (MOLOPT) basis sets, for both the B97M-rV and ωB97X-V density functionals for members of the main-group elements and 3d and noble metals. The resulting small-core PPs and corresponding DZVP, TZVP, and TZV2P basis sets yield notable improvements compared to the original PBE defaults when validated against all electron calculations for redox reaction energies and geometries, binding energies, and vibrational Stark effects for metal monocarbonyls in vacuum. Further validation of the optimized PP/MOLOPT basis set combinations was performed using ab initio molecular dynamics simulations and shows greatly improved agreement with experimental trends for metal surface relaxations and the adsorption behavior of CO on solid metal surfaces.

Critical Role of Thermal Fluctuations for CO Binding on Electrocatalytic Metal Surfaces

This work considers the evaluation of density functional theory (DFT) when comparing against experimental observations of CO binding trends on the strong binding Pt(111) and intermediate binding Cu(111) and for weak binding Ag(111) and Au(111) surfaces important in electrocatalysis. By introducing thermal fluctuations using appropriate statistical mechanical NVT and NPT ensembles, we find that the RPBE and B97M-rV DFT functionals yield qualitatively better metal surface strain trends and CO enthalpies of binding for Cu(111) and Pt(111) than found at 0 K, thereby correcting the overbinding by 0.2 to 0.3 eV to yield better agreement with the enthalpies determined from experiment. The importance of dispersion effects are manifest for the weak CO binding Ag(111) and Au(111) surfaces at finite temperatures in which the RPBE functional does not bind CO at all, while the B97M-rV functional shows that the CO-metal interactions are a mixture of chemisorbed and physisorbed species with binding enthalpies that are within ∼0.05 eV of experiment. Across all M(111) surfaces, we show that the B97M-rV functional consistently predicts the correct atop site preference for all metals due to thermally induced surface distortions that preferentially favor the undercoordinated site. This study demonstrates the need to fully account for finite temperature fluctuations to make contact with the binding enthalpies from surface science experiments and electrocatalysis applications.

d- and s-orbital populations in the d block: unbound atoms in physical vacuum versus chemical elements in condensed matter. A Dronskowski-population analysis

The electron configurations of Ca, Zn and the nine transition elements M in between (and their heavier homologs) are reviewed on the basis of density functional theory and experimental facts. The d-s orbital energy and population patterns are systematically diverse. (i) The dominant valence electron configuration of most free neutral atoms M0 of groups g = 2–12 is 3d g−2 4s 2 (textbook rule), or 3d g−14s 1. (ii) Formal M q+ cations in chemical compounds have the dominant configuration 3d g−q 4s 0 (basic concept of transition metal chemistry). (iii) M0 atoms in metallic phases [M∞] of hcp, ccp(fcc) and bcc structures have intermediate populations near 3d g−1 4s 1 (lower d populations for Ca (ca. ½) and Zn (ca. 10)). Including the 4p valence orbitals, the dominant metallic configuration is 3d g−δ 4(sp) δ with δ ≈ 1.4 (±0.2) throughout (except for Zn). (iv) The 3d,4s population of atomic clusters M m varies for increasing m smoothly from single-atomic 3d g−24s 2 toward metallic 3d g−14s 1. – The textbook rule for the one-electron energies, i.e., ns < (n−1)d, holds ‘in a broader sense’ for the s block, but in general not for the d block, and never for the p block. It is more important to teach realistic atomic orbital (AO) populations such as the ones given above.

Constructing Precise Coordination of Nickel Active Sites on Hierarchical Porous Carbon Framework for Superior Oxygen Reduction

Single-atom catalysts (SACs) with specific coordination environment are expected to be efficient electrocatalysts for oxygen reduction reaction (ORR). Herein, NiN₄ C₁₀ coordination site is constructed through encapsulating Ni²⁺ into the cavity of ZIF-8 as a self-sacrificing precursor and anchoring it on 3D N-doped carbon frameworks. The NiN₄ C₁₀ catalyst shows excellent ORR activity and stability, with a high half-wave potential (0.938 V vs RHE), which is currently the best performances in Ni-based SACs. The remarkable performance with high ORR activity in alkaline solution is attributed to the single-atom nickel active sites with faster electron transport and suitable electronic structure. Moreover, the power density of zinc-air battery assembled by NiN₄ C₁₀ as cathode is 47.1% higher than that of the commercial Pt/C. This work not only provides a facile method to prepare extremely active Ni-based SACs, but also studies the intrinsic mechanism toward the oxygen reduction reaction under alkaline condition.

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.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

[Predictive value of combination of MRI tumor regression grade and apparent diffusion coefficient for pathological complete remission after neoadjuvant treatment of locally advanced rectal cancer]

Objective: Pelvic high-resolution magnetic resonance imaging (MRI) has now become a standard method for evaluating the efficacy of neoadjuvant treatment for locally advanced rectal cancer (LARC). However, this traditional morphological qualitative assessment method based on T2-weighted imaging (T2WI) is not effective in predicting pathological complete remission (pCR). The purpose of this study is to investigate whether combining the magnetic resonance tumor regression grade (mrTRG) with apparent diffusion coefficient (ADC) can improve diagnostic value for pCR after preoperative neoadjuvant chemoradiotherapy (nCRT) of LARC. Methods: This was a diagnostic study. Clinicopathological data of 134 LARC patients who received nCRT and radical surgery in the First Affiliated Hospital of Kunming Medical University from January 2017 to December 2019 were retrospectively analyzed. All the patients underwent MRI which included T2WI and DWI sequences before and 8 weeks after nCRT. Two radiologists independently drew ROIs on T2WI and DWI to estimate mrTRG stage and calculate the mean ADC value. Receiver operating characteristics (ROC) method was applied to evaluate the predict value of mrTRG combined with mean ADC value for pCR. Results: Of 134 LARC patients, 85 were male and 49 were female with median age of 58 (28-82) years. After nCRT, MRI suggested 21 patients (15.7%) had clinical complete remission (cCR), e.g. mrTRG stage 1-2. Postoperative pathology revealed 31 (23.1%) patients had pCR. The evaluations of mrTRG and ADC value by the two readers were highly consistent, and the intra-group correlation coefficients were 0.83 (95% CI: 0.703-0.881) and 0.96 (95% CI: 0.989-0.996), respectively. There was a negative correlation between mrTRG and pCR (r(s)=-0.505, P<0.01), and a positive correlation between mean ADC value and pCR (r(s)=0.693, P<0.01). The ROC curve showed that mrTRG alone had a medium predictive value for pCR, with an area under the curve (AUC) of 0.832 (95% CI: 0.743-0.921); the mean ADC value had a higher predictive value for pCR, with AUC of 0.906 (95% CI: 0.869-0.962). The predictive value of the combined model of mrTRG and ADC value for pCR was significantly better than that of mrTRG alone (P=0.015), and the AUC was 0.908 (95% CI: 0.849-0.968). Conclusion: Both mrTRG and mean ADC value can be non-invasive methods to predict the efficacy of nCRT for LARC. Combining the mean ADC value with mrTRG can result in better pCR prediction.

Expanded Inverse-Sandwich Complexes of Lanthanum Borides: La2B10- and La2B11. J Phys Chem A 2021;125:2622-2630. [PMID: 33739102 DOI: 10.1021/acs.jpca.1c01149]

Inverse-sandwich structures have been observed recently for dilanthanide boride clusters, in which two Ln atoms sandwich a monocyclic B_x ring for x = 7-9. An interesting question is if larger B_x rings are possible to form such inverse-sandwich clusters. Here we address this question by investigating La₂B₁₀^- and La₂B₁₁^- using photoelectron spectroscopy and ab initio quantum chemical calculations. Photoelectron spectra of La₂B₁₀^- and La₂B₁₁^- show complicated, but well-resolved, spectral features that are used to compare with theoretical calculations. We have found that global minimum structures of the two clusters are based on the octa-boron ring. The global minimum of La₂B₁₀^- consists of two chiral enantiomers with C₁ symmetry, which can be viewed as adding a B₂ unit off-plane to the B₈ ring, whereas that of La₂B₁₁^- can be viewed as adding a B₃ unit in-plane to the B₈ ring in a second coordination shell. Chemical bonding analyses reveal localized B-B bonds on the edge of the clusters and delocalized bonds in the expanded boron frameworks. The interactions between the La atoms and the boron frameworks include the unique (d-p)δ bonding, which was found to be the key for inverse-sandwich complexes with monocyclic boron rings. The current study confirms that the largest monocyclic boron ring to form the inverse-sandwich structures is B₉ and provide insights into the structural evolutions of larger lanthanide boride clusters.

[Clinico-pathological and follow-up analysis of 5 skeletal muscle single-organ vasculitis cases]

Objectives: To delineate clinico-pathological features, treatment and outcome of skeletal muscle single-organ vasculitis (SM-SOV). Methods: The clinico-pathological characteristic of SM-SOV cases treated over 3 years in China-Japan Friendship Hospital were retrospectively analyzed and the data were compared with the cases from the literature. Results: Five patients (2 women and 3 men) with a median age of 36 years were included in this study. The main clinical manifestations were lower limb myalgia (5/5) and fever (1/5). The most frequent laboratory findings included high erythrocyte sedimentation rate (5/5), high C reactive protein (5/5) and leukocytosis (1/5). No elevated creatine kinase (CK) was found in these cases. Four patients received electromyogram examination and none of them showed myogenic injury. On MRI, hyperintense signals in T₂ weighted image (T₂WI) and/or short TI inversion recovery (STIR) and normal unenhanced T₁ weighted image (T₁WI) of one or several leg muscles was founded in all 5 patients. All muscle specimens showed nongranulomatous vasculitis without myonecrosis affecting small sized artery (5/5) in perimysia (75.0%, 3/4) or both perimysia and fascia (25.0%, 1/4). Corticosteroids (5/5) and immunosuppressants (5/5) were the main agents prescribed. With a median follow-up of 24 months, sustained remission was observed in 3 patients, relapses occurred in 2 patients. Conclusion: SM-SOV should be considered for patients with lower limb myalgia, high inflammatory markers and normal/low CK level. The diagnosis of SM-SOV should be applied when there are both histologic evidence of vasculitis and a minimum of 6 months of follow-up surveillance without evidences suggesting extra-muscular involvement. Corticosteroid combined with immunosuppressant is effective.

Catalytic Principles from Natural Enzymes and Translational Design Strategies for Synthetic Catalysts

As biocatalysts, enzymes are characterized by their high catalytic efficiency and strong specificity but are relatively fragile by requiring narrow and specific reactive conditions for activity. Synthetic catalysts offer an opportunity for more chemical versatility operating over a wider range of conditions but currently do not reach the remarkable performance of natural enzymes. Here we consider some new design strategies based on the contributions of nonlocal electric fields and thermodynamic fluctuations to both improve the catalytic step and turnover for rate acceleration in arbitrary synthetic catalysts through bioinspired studies of natural enzymes. With a focus on the enzyme as a whole catalytic construct, we illustrate the translational impact of natural enzyme principles to synthetic enzymes, supramolecular capsules, and electrocatalytic surfaces.

Challenges for density functional theory: calculation of CO adsorption on electrocatalytically relevant metals

We assess four DFT functionals, RTPSS, RPBE, SCAN and B97M-rV, for surface interactions. We find that B97M-rV predicts the correct site preference for CO binding on Ag and Au while RTPSS performs well for surface relaxations and binding of CO on Pt and Cu.

Unravelling the Enigma of Nonoxidative Conversion of Methane on Iron Single-Atom Catalysts

The direct, nonoxidative conversion of methane on a silica-confined single-atom iron catalyst is a landmark discovery in catalysis, but the proposed gas-phase reaction mechanism is still open to discussion. Here, we report a surface reaction mechanism by computational modeling and simulations. The activation of methane occurs at the single iron site, whereas the dissociated methyl disfavors desorption into gas phase under the reactive conditions. In contrast, the dissociated methyl prefers transferring to adjacent carbon sites of the active center (Fe₁ ©SiC₂ ), followed by C-C coupling and hydrogen transfer to produce the main product (ethylene) via a key -CH-CH₂ intermediate. We find a quasi Mars-van Krevelen (quasi-MvK) surface reaction mechanism involving extracting and refilling the surface carbon atoms for the nonoxidative conversion of methane on Fe₁ ©SiO₂ and this surface process is identified to be more plausible than the alternative gas-phase reaction mechanism.

[The early results of pulmonary autograft mitral valve replacement (Ross Ⅱ) in infants]

Objective: To evaluate the early results of pulmonary autograft mitral valve replacement (Ross Ⅱ procedure) in infants with intractable congenital mitral valve lesions. Methods: Between August 2018 and September 2019, 6 infants underwent mitral valve replacement with a pulmonary autograft in Department of Cardiovascular Surgery, Guangzhou Women and Children's Medical Center. There were 2 males and 4 females.The age at surgery ranged from 50 days to 1 year old.Preoperative diagnoses included severe to critic mitral valve insuffiency in all patients, moderate mitral valve stenosis in 3 patients, and mitral valve prolapse in one. When the pulmonary autograft was harvested, a cuff of bovine or autologous pericardium was sewn onto the proximal (infundibular) end of the autograft ( "top-hat" configuration). The distal (pulmonary) end of the autograft was secured to the mitral annulus.At the level of the left atrial free wall, the pericardial cuff was progressively tailored and sewn onto the atrial wall to remain away from the ostia of the pulmonary veins and to maintain normal morphology of the autograft. The bovine jugular valved conduit was used to reconstruct the right ventricular outflow tract. Results: There was one early death due to sudden cardiac arrest at the night of surgery day. The remaining 5 patients were successfully recovered and discharged. Follow-up of survivors ranged from 3 to 13 months. Echocardiographic follow-up demonstrated the flow velocity across the mitral valve position was 1.5 to 2.3 m/s, with a means gradient of 4 to 6 mmHg (1 mmHg=0.133 kPa). Four patients showed mild mitral insuffiency, normal left atrium and ventricle size and left ventricle ejection fraction.One patient had moderate mitral insuffiency, pulmonary valve endocarditis, and reduced left ventricle ejection fraction. The clinical symptoms of all survivals improved significantly and the weight gain were satisfactory. Conclusion: Pulmonary autograft mitral valve replacement may be a feasible and effective remedial surgical strategy for young infants with intractable congenital mitral valve lesions.

[Long-term oncological outcomes of laparoscopic versus abdominal surgery in stage Ⅰa1 （LVSI+）-Ⅰb1 cervical cancer patients with different tumor size: a big database in China]

Objective: To compare the long-term oncological outcomes between laparoscopic and abdominal surgery in stage Ⅰa1 （lymph-vascular space invasion-positive, LVSI⁺）- Ⅰb1 cervical cancer patients with different tumor sizes. Methods: Based on the Big Database of Clinical Diagnosis and Treatment of Cervical Cancer in China (1538 project database), patients with stage Ⅰa1 （LVSI⁺）-Ⅰb1 cervical cancer who treated by laparoscopic or abdominal surgery were included. The 5-year overall survival (OS) and 5-year disease-free survival (DFS) between the two surgical approaches were compared under 1∶1 propensity score matching (PSM) in different tumor diameter stratification. Results: (1) A total of 4 891 patients with stage Ⅰa1 （LVSI⁺）-Ⅰb1 cervical cancer who underwent laparoscopy or laparotomy from January 1, 2009 to December 31, 2016 were included in the 1538 project database. Among them, 1 926 cases in the laparoscopic group and 2 965 cases in the abdominal group. There were no difference in 5-year OS and 5-year DFS between the two groups before matching. Cox multivariate analysis suggested that laparoscopic surgery was associated with lower 5-year DFS (HR=1.367, 95%CI: 1.105-1.690, P=0.004). After 1∶1 PSM matching, 1 864 patients were included in each group, and there was no difference in 5-year OS between the two groups （94.1% vs 95.4%, P=0.151）. While, the inferior 5-year DFS was observed in the laparoscopic group (89.0% vs 92.3%, P=0.004). And the laparoscopic surgery was associated with lower 5-year DFS (HR=1.420, 95%CI: 1.109-1.818, P=0.006). (2) In stratification analysis of different tumor sizes, and there were no difference in 5-year OS and 5-year DFS between the laparoscopic group and abdominal group in tumor size ≤1 cm, >1-2 cm and >2-3 cm stratification (all P>0.05). Cox multivariate analysis showed that laparoscopic surgery were not related to 5-year OS and 5-year DFS (P>0.05). In the stratification of tumor size >3-4 cm, there was no difference in 5-year OS between the two groups (P>0.05). The 5-year DFS in the laparoscopic group was worse than that in the abdominal group (75.7% vs 85.8%, P=0.025). Cox multivariate analysis suggested that laparoscopic surgery was associated with lower 5-year DFS (HR=1.705, 95%CI: 1.088-2.674, P=0.020). Conclusions: For patients with stage Ⅰa1 （LVSI⁺）-Ⅰb1 cervical cancer, laparoscopic surgery is associated with lower 5-year DFS, and the adverse effect of laparoscopic surgery on oncology prognosis is mainly reflected in patients with tumor size >3-4 cm. For patients with tumor sizes ≤1 cm, >1-2 cm and >2-3 cm, there are no difference in oncological prognosis between the two surgical approaches.

[Progress of researches on the role of neutrophil extracellular traps in the immune responses against parasites]

Neutrophil extracellular trap (NET) is a type of bead-like, fibrous and reticular substances that is actively released by activated inflammatory neutrophils during the stage of infections or inflammatory responses. NET, which is composed of chromatin DNA and multiple intracellular protein components, may wrap pathogens to limit their diffusions. Meanwhile, NET may kill pathogens via a wide range of antibacterial proteins, which is considered as the third antibacterial mechanism of neutrophils, in addition to phagocytosis and degranulation. Recent studies have shown the involvement of NET in the immune response against parasitic infections. This review summarizes the advances of NETs in the immune responses against parasitic infections, so as to provide insights into the elucidation of the pathogenesis and development of therapeutics of parasitic diseases.

Formation and Characterization of a BeOBeC Multiple Radical Featuring a Quartet Carbyne Moiety

Through reaction of beryllium dimers with carbon monoxide, a carbonyl complex BeBeCO is formed in solid neon. Upon visible light excitation, the BeBeCO complex rearranges to a BeCOBe isomer, which further isomerizes to a low-energy BeOBeC species under UV-visible light excitation. These species are identified on the basis of infrared absorption spectroscopy with isotopic substitutions and quantum chemical studies. The BeOBeC molecule is characterized to be a multiple radical species having an electronic quintet ground state featuring an unusual quartet carbyne unit with three unpaired electrons on the carbon center. Bonding analysis indicates that the strong Pauli repulsion between carbon 2s lone pair electrons and the σ electrons of the BeOBe fragment significantly weakens the Be-C bonding and destabilizes the triplet state of the BeOBeC radical with a doublet carbyne unit. The three-center π-bonding of BeOBe is also found to play a role in stabilizing the quartet carbyne.

[Clinical analysis and prognosis factors of malignancy in the patients with mucinous cystic neoplasms of the pancreas]

Objective: To examine clinic pathological features of mucinous cystic neoplasms (MCN) of the pancreas and explore the prognosis factors associated with malignant transformation of MCN of the pancreas. Methods: This multicenter retrospective study included all patients with pancreatic MCN underwent surgery at Department of Pancreatic Surgery, Zhongshan Hospital of Fudan University between January 2008 and December 2018 and patients with MCN who confirmed by postoperative pathology from Multicenter Pancreatic Cystic Tumor Database. There were 50 males (14.4%) and 297 females (85.6%) and the mean age was 48.6 years (range: 24-77 years). According to the pathological results, all patients were divided into benign lesion group (including MCN and which associated with low/medium grade dysplasia) and malignant lesion group (including MCN with high-grade dysplasia or invasive carcinoma) . The preoperative clinical pathology and imaging features of the two groups were analyzed, and the risk factors associated with malignant transformation of MCN were statistically analyzed. Results: This multicenter retrospective study included 347 patients. Twenty-four of the 347 patients were malignant, including 7 males and 17 females. Univariate analysis showed that age, gender, carcino-embryonic antigen (CEA) , CA19-9, CA125, tumor maximum diameter, and tumor location were remarkably different in the two groups (P<0.05) . Logistic regression analysis found that the preoperative tumor maximum diameter (OR=1.023, 95% CI: 1.002-1.045, P=0.035) was an independent risk factor for MCN malignant transformation. Conclusions: Age, gender, CEA, CA19-9, CA125, tumor maximum diameter, and tumor location are important features of MCN malignant lesions.The maximum diameter of the preoperative tumor is an independent risk factor for MCN malignant transformation.

Interplay of water and a supramolecular capsule for catalysis of reductive elimination reaction from gold

Supramolecular assemblies have gained tremendous attention due to their ability to catalyze reactions with the efficiencies of natural enzymes. Using ab initio molecular dynamics, we identify the origin of the catalysis by the supramolecular capsule Ga₄L₆^12- on the reductive elimination reaction from gold complexes and assess their similarity to natural enzymes. By comparing the free energies of the reactants and transition states for the catalyzed and uncatalyzed reactions, we determine that an encapsulated water molecule generates electric fields that contributes the most to the reduction in the activation free energy. Although this is unlike the biomimetic scenario of catalysis through direct host-guest interactions, the electric fields from the nanocage also supports the transition state to complete the reductive elimination reaction with greater catalytic efficiency. However it is also shown that the nanocage poorly organizes the interfacial water, which in turn creates electric fields that misalign with the breaking bonds of the substrate, thus identifying new opportunities for catalytic design improvements in nanocage assemblies.

Planar B41- and B42- clusters with double-hexagonal vacancies

Since the discovery of the B₄₀ borospherene, research interests have been directed to the structural evolution of even larger boron clusters. An interesting question concerns if the borospherene cages persist in larger boron clusters like the fullerenes. Here we report a photoelectron spectroscopy (PES) and computational study on the structures and bonding of B₄₁^- and B₄₂^-, the largest boron clusters characterized experimentally thus far. The PE spectra of both clusters display broad and complicated features, suggesting the existence of multiple low-lying isomers. Global minimum searches for B₄₁^- reveal three low-lying isomers (I-III), which are all related to the planar B₄₀^- structure. Isomer II (C_s, ¹A') possessing a double hexagonal vacancy is found to agree well with the experiment, while isomers I (C_s, ³A'') and III (C_s, ¹A') both with a single hexagonal vacancy are also present as minor isomers in the experiment. The potential landscape of B₄₂^- is found to be much more complicated with numerous low-lying isomers (VII-XII). The quasi-planar structure VIII (C₁, ²A) containing a double hexagonal vacancy is found to make major contributions to the observed PE spectrum of B₄₂^-, while the other low-lying isomers may also be present to give rise to a complicated spectral pattern. Chemical bonding analyses show isomer II of B₄₁^- (C_s, ¹A') and isomer VIII of B₄₂^- (C₁, ²A) are π aromatic, analogous to that in the polycyclic aromatic hydrocarbon C₂₇H₁₃⁺ (C_2v, ¹A₁). Borospherene cage isomers are also found for both B₄₁^- and B₄₂^- in the global minimum searches, but they are much higher energy isomers.

Quadruple bonding between iron and boron in the BFe(CO)3- complex

While main group elements have four valence orbitals accessible for bonding, quadruple bonding to main group elements is extremely rare. Here we report that main group element boron is able to form quadruple bonding interactions with iron in the BFe(CO)3- anion complex, which has been revealed by quantum chemical investigation and identified by mass-selected infrared photodissociation spectroscopy in the gas phase. The complex is characterized to have a B-Fe(CO)3- structure of C3v symmetry and features a B-Fe bond distance that is much shorter than that expected for a triple bond. Various chemical bonding analyses indicate that the complex involves unprecedented B≣Fe quadruple bonding interactions. Besides the common one electron-sharing σ bond and two Fe→B dative π bonds, there is an additional weak B→Fe dative σ bonding interaction. This finding of the new quadruple bonding indicates that there might exist a wide range of boron-metal complexes that contain such high multiplicity of chemical bonds.

A Supramolecular Radical Dimer: High-Efficiency NIR-II Photothermal Conversion and Therapy

Photothermal therapy at the NIR-II biowindow (1000-1350 nm) is drawing increasing interest because of its large penetration depth and maximum permissible exposure. Now, the supramolecular radical dimer, fabricated by N,N'-dimethylated dipyridinium thiazolo[5,4-d]thiazole radical cation (MPT^.+ ) and cucurbit[8]uril (CB[8]), achieves strong absorption at NIR-II biowindow. The supramolecular radical dimer (2MPT^.+ -CB[8]) showed highly efficient photothermal conversion and improved stability, thus contributing to the strong inhibition on HegG2 cancer cell under 1064 nm irradiation even penetrating through chicken breast tissue. This work provides a novel approach to construct NIR-II chromophore by tailor-made assembly of organic radicals. It is anticipated that this study provides a new strategy to achieve NIR-II photothermal therapy and holds promises in luminescence materials, optoelectronic materials, and also biosensing.

[Clinical study on asthma and aspirin asthma affecting chronic rhinosinusitis]

Objective:The aim of this study is to observe the effects of asthma and aspirin asthma on chronic rhinosinusitis and to explore the corresponding clinical value. Method: Eighty-six patients with CRS and asthma who were treated in the outpatient clinic during March 2015 to January 2018 were divided into asthma group(52 cases) and aspirin asthma group(34 cases) according to asthma and aspirin asthma. The clinical symptoms of the two groups were analyzed by symptomatic VAS score, Lund-Mackay score of sinus CT, and Lund-Kennedy score by nasal endoscopy.The scores of the two groups were compared under different lung function. Enzyme-linked immunosorbent assay the levels of inflammatory markers IL-5,IL-17,IFN-γ and TNF-α in the sinus secretions of the two groups were detected.Result:There were no significant differences in age, gender, smoking history, allergy history, surgical history and course of disease between the two groups(P<0.05), suggesting that the data were comparable. The sinus CT results showed that compared with the aspirin asthma group, the asthmatic group had irregular turbinates and a large turbinate,as shown in Figure 1. There were significant differences between the two groups in VAS score,Lund-Mackay score of sinus CT and Lund-Kennedy score by nasal endoscopy.The difference was statistically significant(P<0.05). And the forehead and/or facial pain or pain in the symptomatic VAS score(P<0.05), the Lund-Mackay score of the sinus CT(P<0.05),and intranasal.The difference in the Lund-Kennedy score(P<0.05) was statistically significant.There were significant differences in the distribution of lung function levels between the two groups of patients with mild airway obstructive respiratory dysfunction and pulmonary ventilation obstructive disorder(P<0.05).The average levels of IL-5,IL-17,IFN-γ and TNF-α in the aspirin asthma group were significantly lower than those in the asthma group(P<0.05).Conclusion:Aspirin-induced CRS produces asthma symptoms more severely than traditional asthma symptoms, but the induced local inflammatory response is relatively weak, and the mechanism may be closely related to IL-5,IL-17,IFN-γ and TNF-α levels.

L-glutamine protects mouse brain from ischemic injury via up-regulating heat shock protein 70

INTRODUCTION

L-glutamine is an antioxidant that plays a role in a variety of biochemical processes. Given that oxidative stress is a key component of stroke pathology, the potential of L-glutamine in the treatment of ischemic stroke is worth exploring.

AIMS

In this study, we investigated the effect and mechanisms of action of L-glutamine after cerebral ischemic injury.

RESULTS

L-glutamine reduced brain infarct volume and promoted neurobehavioral recovery in mice. L-glutamine administration increased the expression of heat-shock protein 70 (HSP70) in astrocytes and endothelial cells. Such effects were abolished by the coadministration of Apoptozole, an inhibitor of the ATPase activity of HSP70. L-glutamine also reduced oxidative stress and neuronal apoptosis, and increased the level of superoxide dismutase, glutathione, and brain-derived neurotrophic factor. Cotreatment with Apoptozole abolished these effects. Cell culture study further revealed that the conditioned medium from astrocytes cultured with L-glutamine reduced the apoptosis of neurons after oxygen-glucose deprivation.

CONCLUSION

L-glutamine attenuated ischemic brain injury and promoted functional recovery via HSP70, suggesting its potential in ischemic stroke therapy.

La3B14-: an inverse triple-decker lanthanide boron cluster

We report the observation of the first inverse triple-decker complex in a tri-lanthanide-doped boron cluster. Photoelectron spectroscopy of La₃B₁₄^- reveals well-resolved photodetachment transitions. Quantum chemical studies show that the most stable structure of the La₃B₁₄^- cluster exhibits a tilted La-B₈-La-B₈-La inverse triple-decker structure with two conjoined B₈ rings sharing a pair of B atoms due to strong inter-layer B-B bonding. The tilted structure enhances both B-B and B-La bonding, resulting in a highly stable inverse triple-decker structure. Theoretical calculations further show that multi-decker conjoined structures are viable as a new class of 1D lanthanide boron nanostructures.

Re©B8- and Re©B9-: New Members of the Transition-Metal-Centered Borometallic Molecular Wheel Family

Transition-metal-centered monocyclic boron wheel clusters (M©B _n ^q) represent a family of interesting borometallic compounds with double aromaticity. A variety of early and late transition metal atoms have been found to form such structures with high symmetries and various B _n ring sizes. Here we report a combined photoelectron spectroscopy and quantum-chemistry theoretical study of two M©B _n^- clusters from the middle of the transition metal series: Re©B₈^- and Re©B₉^-. Global minimum structure searches revealed that ReB₈^- adopts a pseudo- C_{8 v} structure while ReB₉^- is a perfectly planar D_{9 h} molecular wheel. Chemical bonding analyses showed that both clusters exhibit σ and π double aromaticity and obey the electronic design principle for metal-centered borometallic molecular wheels. The central Re atoms are found to possess unusually low oxidation states of +I in Re©B₈^- and +II in Re©B₉^-, i.e., the Re atom behaves similarly to late transition metal elements (Ru, Fe, Co, Rh, Ir) in the M©B _n^- molecular wheels. These two clusters become new members of the family of transition-metal-centered monocyclic borometallic molecular wheels, which may be viable for chemical syntheses with appropriate ligands.

[The prevalence and related factors of HBV infection among adults in Mianyang]

Objective: To analyze the prevalence and related factors of HBV infection among people aged 18 years old and above in Mianyang city. Methods: A total of 260 950 residents, living in Mianyang city more than 6 months, aging 18 years old and above were employed by multi-stage random sampling method from November 2014 to September 2015. Questionnaire survey was conducted on participants using a self-designed questionnaire, including general demographic characteristics, family history of Hepatitis B, history of Hepatitis B vaccination and history of present illness, etc. 5ml blood was collected from all participants, and the blood samples were detected for HBsAg by enzyme-linked immunosorbent assay (ELISA). The multivariate unconditional logistic regression was performed to identify the related factors of positive HBsAg. Results: Among the 260 950 subjects, 113 184 were males (43.37%), 147 766 were females (56.63%), and the average age was (47.68±17.36) years old. The positive rate of HBsAg was 6.10%(15 822 cases). Subjects who were 25-34 years old (OR=1.23), 35-44 years old (OR=1.26), 45-54 years old (OR=1.23), and 55-64 years old (OR=1.34) were more likely to be HBsAg positive,65 years and older (OR=0.88) were less likely to be, compared with subjects aging 18-24 years old; males were more likely to be HBsAg positive compared with females (OR=1.35); people living in Fucheng district were more likely to be HBsAg positive compared with who living in Jiangyou district(OR=1.91); married people were more likely to be HBsAg positive compared with unmarried ones (OR=1.36); medical staff were less likely to be HBsAg positive compared with non-medical staff (OR=0.61); subjects with a surgery history were more likely to HBsAg positive compared with who without (OR=1.13); subjects with trauma history were more likely to HBsAg positive compared with who without (OR=1.13); people with history of Hepatitis B were more likely to HBsAg positive compared with who without (OR=4.21); people with Hepatitis B vaccination history were less likely to be HBsAg positive compared with who without (OR=0.48); all the P values above were less than 0.05. Conclusion: The positive rate of HBsAg among adults in Mianyang city was very high, and we should pay more attention to people aging between 25 and 64 years old, male, medical staff, with surgery history, trauma history, and a family history of Hepatitis B and Hepatitis B vaccination history.

[La(η x -B x )La]- (x = 7-9): a new class of inverse sandwich complexes

Despite the importance of bulk lanthanide borides, nanoclusters of lanthanide and boron have rarely been investigated. Here we show that lanthanide-boron binary clusters, La₂B _x ^-, can form a new class of inverse-sandwich complexes, [Ln(η ^x -B _x )Ln]^- (x = 7-9). Joint experimental and theoretical studies reveal that the monocyclic B _x rings in the inverse sandwiches display similar bonding, consisting of three delocalized σ and three delocalized π bonds. Such monocyclic boron rings do not exist for bare boron clusters, but they are stabilized by the sandwiching lanthanide atoms. An electron counting rule is proposed to predict the sizes of the B _x ring that can form stable inverse sandwiches. A unique (d-p)δ bond is found to play important roles in the stability of all three inverse-sandwich complexes.

[The influence and mechanisms of purple sweet potato anthocyanins on the growth of bladder cancer BIU87 cell]

Objective: To observe the effect of purple sweet potato anthocyanins on the proliferation of bladder cancer cell line BIU87 and to investigate the molecular mechanisms. Methods: Bladder cancer BIU87 cells were cultured and exposed to anthocyanins at the different concentrations of 100, 200, 400, and 800 μg/ml respectively. The growth inhibition of anthocyanins on BIU87 cells were evaluated by morphometry and cell counting kit-8 (CCK-8) assay, and the cell apoptosis rate was detected by Flow cytometry (FCM). Results: Morphometry showed that the number of BIU87 cells decreased, the volume shrank, the intercellular space enlarged, the ability of cell adherence weakened, and the cell shape changed when the concentration of anthocyanins increased. CCK-8 assay showed that when 100, 200, 400, 800 μg/ml anthocyanins treated BIU87 cells for 48 h, the absorbance was 24 ± 0.07, 1.15 ± 0.11, 0.90 ± 0.08, 0.56 ± 0.09, respectively. Compared with the control group, anthocyanins-treated groups significantly inhibited the proliferation of BIU87 cells (P<0.05). FCM test showed that after treatment with different doses of anthocyanins, the apoptosis rate was 7.31%, 11.11%, 25.96%, 36.28%, respectively, and with the concentration of anthocyanins being higher, the apoptosis rate of BIU87 cells was being higher. Conclusion: Purple sweet potato anthocyanins can inhibit the growth of bladder cancer BIU87 cells through inducing cell apoptosis in a dose-dependent manner.