Typical ophiolitic rock assemblages such as siliciclastic rocks, basalts and gabbros, together with the subduction-related intermediate-acidic intrusive rocks, are newly discovered in the Tongjiang-Fuyuan area of the Heilongjiang Provence, NE China. To determine the formation age and genesis of the mafic rocks (basalts and gabbros) and intermediate-acidic intrusive rocks (granodiorites) in the area, as well as their geodynamic settings, the whole-rock geochemical analysis and zircon LA-ICP-MS U-Pb dating were carried out. Zircon U-Pb results suggest that the granodiorites are 93–95 Ma and gabbro is 95 Ma, respectively. Geochemical results show that the gabbros and basalts exhibit characteristics of ocean island basalt (OIB) affinity and are typically related to having originated from mantle plumes. While the granodiorites show the nature of the island-arc magmatic rocks and may originate from the lower crust. Based on the coeval igneous rock associations and regional tectonic evolution, we conclude that the late Cretaceous magmatic rocks in the Tongjiang-Fuyuan area are the product of continuous subduction of the Palaeo-Pacific plate and reflect the subduction rollback process of the Palaeo-Pacific plate.

Coastal eutrophication and hypoxia remain a persistent environmental crisis despite the great efforts to reduce nutrient loading and mitigate associated environmental damages. Symptoms of this crisis have appeared to spread rapidly, reaching developing countries in Asia with emergences in Southern America and Africa. The pace of changes and the underlying drivers remain not so clear. To address the gap, we review the up-to-date status and mechanisms of eutrophication and hypoxia in global coastal oceans, upon which we examine the trajectories of changes over the 40 years or longer in six model coastal systems with varying socio-economic development statuses and different levels and histories of eutrophication. Although these coastal systems share common features of eutrophication, site-specific characteristics are also substantial, depending on the regional environmental setting and level of social-economic development along with policy implementation and management. Nevertheless, ecosystem recovery generally needs greater reduction in pressures compared to that initiated degradation and becomes less feasible to achieve past norms with a longer time anthropogenic pressures on the ecosystems. While the qualitative causality between drivers and consequences is well established, quantitative attribution of these drivers to eutrophication and hypoxia remains difficult especially when we consider the social economic drivers because the changes in coastal ecosystems are subject to multiple influences and the cause–effect relationship is often non-linear. Such relationships are further complicated by climate changes that have been accelerating over the past few decades. The knowledge gaps that limit our quantitative and mechanistic understanding of the human-coastal ocean nexus are identified, which is essential for science-based policy making. Recognizing lessons from past management practices, we advocate for a better, more efficient indexing system of coastal eutrophication and an advanced regional earth system modeling framework with optimal modules of human dimensions to facilitate the development and evaluation of effective policy and restoration actions.

Brucellosis is one of the most serious and widespread zoonotic diseases, which seriously threatens human health and the national economy. This study was based on the T/B dominant epitopes of Brucella outer membrane protein 22 (Omp22), outer membrane protein 19 (Omp19) and outer membrane protein 28 (Omp28), with bioinformatics methods to design a safe and effective multi-epitope vaccine. The amino acid sequences of the proteins were found in the National Center for Biotechnology Information (NCBI) database, and the signal peptides were predicted by the SignaIP-5.0 server. The surface accessibility and hydrophilic regions of proteins were analysed with the ProtScale software and the tertiary structure model of the proteins predicted by I-TASSER software and labelled with the UCSF Chimera software. The software COBEpro, SVMTriP and BepiPred were used to predict B cell epitopes of the proteins. SYFPEITHI, RANKpep and IEDB were employed to predict T cell epitopes of the proteins. The T/B dominant epitopes of three proteins were combined with HEYGAALEREAG and GGGS linkers, and carriers sequences linked to the N- and C-terminus of the vaccine construct with the help of EAAAK linkers. Finally, the tertiary structure and physical and chemical properties of the multi-epitope vaccine construct were analysed. The allergenicity, antigenicity and solubility of the multi-epitope vaccine construct were 7.37–11.30, 0.788 and 0.866, respectively. The Ramachandran diagram of the mock vaccine construct showed 96.0% residues within the favoured and allowed range. Collectively, our results showed that this multi-epitope vaccine construct has a high-quality structure and suitable characteristics, which may provide a theoretical basis for future laboratory experiments.

Over recent decades, Chinese giant salamanders Andrias spp. have declined dramatically across much of their range. Overexploitation and habitat degradation have been widely cited as the cause of these declines. To investigate the relative contribution of each of these factors in driving the declines, we carried out standardized ecological and questionnaire surveys at 98 sites across the range of giant salamanders in China. We did not find any statistically significant differences between water parameters (temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, alkalinity, hardness and flow rate) recorded at sites where giant salamanders were detected by survey teams and/or had been recently seen by local respondents, and sites where they were not detected and/or from which they had recently been extirpated. Additionally, we found direct and indirect evidence that the extraction of giant salamanders from the wild is ongoing, including within protected areas. Our results support the hypothesis that the decline of giant salamanders across China has been primarily driven by overexploitation. Data on water parameters may be informative for the establishment of conservation breeding programmes, an initiative recommended for the conservation of these species.

The single initial Global Positioning System (GPS) has been expanded into multiple global and regional navigation satellite systems (multi-GNSS/RNSS) as the Global Navigation Satellite System (GLONASS) is restored and the BeiDou Navigation Satellite System (BDS), Galileo Satellite Navigation System (Galileo) and Quasi-Zenith Satellite System (QZSS) evolve. Using the differences among these five systems, the paper constructs a consolidated multi-GNSS/RNSS precise point positioning (PPP) observation model. A large number of datasets from Multi-GNSS Experiment (MGEX) stations are employed to evaluate the PPP performance of multi-GNSS/RNSS. The paper draws three main conclusions based on the experimental results. (1) The combined GPS/GLONASS/Galileo/BDS/QZSS presents the PPP with the shortest mean convergence time of 11·5 min, followed by that of GPS/GLONASS/Galileo/BDS (12·4 min). (2) The combined GPS/GLONASS/BDS/Galileo/QZSS shows the optimal PPP performance when the cut-off elevation angle is basically the same because of the rich observation data due to a large number of satellites. To be specific, for combined GPS/GLONASS/BDS/Galileo/QZSS, the PPP convergence percentage is 80·9% higher relative to other combined systems under 35° cut-off elevation angle, and the percentages of the root mean square values of PPP within 0–5 cm are enhanced by 80·5%, 81·5% and 87·3% in the North, East and Up directions relative to GPS alone at 35° cut-off elevation angle. (3) GPS alone fails to conduct continuous positioning due to the insufficiency of visible satellites at 40° cut-off elevation angle, while the kinematic PPP of multi-GNSS/RNSS remains capable of obtaining positioning solutions with relatively high accuracy, especially in the horizontal direction.

The mortality of coronavirus disease 2019 (COVID-19) differs between countries and regions. This study aimed to clarify the clinical characteristics of imported and second-generation cases in Shaanxi. This study included 134 COVID-19 cases in Shaanxi outside Wuhan. Clinical data were compared between severe and non-severe cases. We further profiled the dynamic laboratory findings of some patients. In total, 34.3% of the 134 patients were severe cases, 11.2% had complications. As of 7 March 2020, 91.8% patients were discharged and one patient (0.7%) died. Age, lymphocyte count, C-reactive protein, erythrocyte sedimentation rate, direct bilirubin, lactate dehydrogenase and hydroxybutyrate dehydrogenase showed difference between severe and no-severe cases (all P < 0.05). Baseline lymphocyte count was higher in survived patients than in non-survivor case, and it increased as the condition improved, but declined sharply when death occurred. The interleukin-6 (IL-6) level displayed a downtrend in survivors, but rose very high in the death case. Pulmonary fibrosis was found on later chest computed tomography images in 51.5% of the pneumonia cases. Imported and second-generation cases outside Wuhan had a better prognosis than initial cases in Wuhan. Lymphocyte count and IL-6 level could be used for evaluating prognosis. Pulmonary fibrosis as the sequelae of COVID-19 should be taken into account.

This paper presents an investigation of the precise point positioning (PPP) performance of a combined solution from BDS-2 and BDS-3 satellites. To simultaneously process different BDS signal observations, i.e., B1/B1C, B2/B2a and B3C, undifferenced and uncombined observations with ionosphere delay constrained by the deterministic plus stochastic ionosphere model are used in the basic model. Special attention is paid to code bias and receiver clock parameters in the derivation of the observation model. The analysis is carried out using more than one-month data for BDS-2 and BDS-3 collected at the CANB, DWIN, KNDY and PETH stations in the Asia-Pacific region. The results suggest that compared with BDS-2 alone, the BDS-2 and BDS-3 solution provides significantly more accurate PPP, with increases of 28%, 21% and 5% in the up, north and east directions, respectively. In addition, the average root mean square error decreases to 0·21, 0·13 and 0·16 m for the three directions. Furthermore, the PPP convergence time for BDS-2 and BDS-3 is about 1·5 h and less than 1 h for the horizontal and vertical components, respectively, whereas that for BDS-2 alone is about 2·3 h for both directions.

Flat products of carbon nanotubes (CNTs) reinforced Al matrix composites were fabricated using flake powder metallurgy via shift-speed ball milling and hot-rolling. The evolution of CNTs during preparation and the final distribution in the Al matrix were investigated, and the effect of CNT content on mechanical properties were discussed. Due to the combined effect of uniform dispersion of CNTs, structural integrity, interfacial bonding and directional alignment, the balance between high strength and ductility was successfully achieved in the annealed rolled composites with 1.5 wt% CNT addition, with the value of 382.6 MPa in tensile strength and 9.8% in fracture ductility. The load transfer strengthening was the main mechanism of the strength enhancement with CNTs addition. In addition, a strong rotated cube {001}〈110〉 texture was found in the final flat product of rolled composites. This study provides an effective route to produce and improve the mechanical properties of CNT/Al flat products.

Ceramics are strong but brittle. According to the classical theories, ceramics are brittle mainly because dislocations are suppressed by cracks. Here, the authors report the combined elastic and plastic deformation measurements of nanoceramics, in which dislocation-mediated stiff and ductile behaviors were detected at room temperature. In the synchrotron-based deformation experiments, a marked slope change is observed in the stress–strain relationship of MgAl2O4 nanoceramics at high pressures, indicating that a deformation mechanism shift occurs in the compression and that the nanoceramics sample is elastically stiffer than its bulk counterpart. The bulk-sized MgAl2O4 shows no texturing at pressures up to 37 GPa, which is compatible with the brittle behaviors of ceramics. Surprisingly, substantial texturing is seen in nanoceramic MgAl2O4 at pressures above 4 GPa. The observed stiffening and texturing indicate that dislocation-mediated mechanisms, usually suppressed in bulk-sized ceramics at low temperature, become operative in nanoceramics. This makes nanoceramics stiff and ductile.

Sn–Sb alloy is an ideal candidate for lead-free solder; however, its performance has been inferior to that of Sn–Pb alloy. Here, the authors used ab initio molecular dynamics simulation to investigate the interatomic interaction in Sn–Sb-based lead-free solders. By calculating the electron density distribution, bond population, and partial density of states, the authors found that the Sn–Sb bonds are a mixture of nonlocalized metal and localized covalent bonds. The covalent bond between Sn and Sb is easy to break at higher temperatures, so Sn–Sb (6.4 wt%) had better fluidity than other studied Sn–Sb alloys. Furthermore, adding Cu or Ag into Sn–Sb alloys can decrease the strength of covalent bonds and stabilize the metal bonds, which improves the metallicity and wettability of the Sn–Sb–Cu and Sn–Sb–Cu–Ag systems when the temperature increases. These results are all in good agreement with experimental findings and have significant value for the development of new solder alloys.

Here we report a new find of abundant woody debris and cones in stratum of two sections located to the east of the Qinghai Lake basin in China. Analysis of the anatomical structure of the wood and cones confirmed that they are Picea crassifolia Kom. The results of accelerator mass spectrometry 14C dating indicate that the buried Qinghai spruce grew during 9.7–4.2 ka, and the ages of the large trunks or branches are mainly concentrated within the interval 7.5–6.5 ka. This finding gives direct evidence at the species level about the presence of coniferous forest in the early–middle Holocene in Qinghai lake basin. In addition, the buried cones suggest that the early-middle Holocene environment was suitable for the propagation of Picea crassifolia Kom. The variations in the occurrence of Qinghai spruce forest in the Holocene probably reflect changes in humidity/moisture. The humid early-middle Holocene was suitable for the growth and reproduction of Qinghai spruce forest, while a shift toward an increasingly arid climate during the late Holocene resulted in the disappearance of Picea crassifolia Kom. from the Qinghai Lake basin, although human activities may also have contributed to the environmental change.

This study focuses on the main factors determining the apparent porosity of porous bioceramics prepared using small organic foam spheres as the pore-making reagent, in order to determine the best technical parameters for preparing porous bioceramics. In every experiment, only one of these factors (the time of heating, the sintering temperature, the mass ratio between small organic foam spheres and beta-tricalcium phosphate (β-TCP) powder, and the rate of the temperature rise) was changed, while the others were kept constant. In each case the apparent porosity was tested and the relation between the specific variable and apparent porosity was observed. Finally, the optimum technical parameters were deduced. The apparent porosity shows an inverse linear relation to the time of heating and the sintering temperature, and is approximately proportional to the mass ratio between the small organic foam spheres and the β-TCP powder and the rate of temperature rise. These factors have important influences on the apparent porosity. The optimum conditions were: heating time (soak time) 120 min, sintering temperature 850ºC, mass ratio 0.25, and a rate of temperature increase of 120ºC h–1.

The influence of heat treatment (homogenization) on the microstructure, mechanical behavior, and soft magnetic properties of a face-centered cubic (fcc)-based high-entropy alloy (HEA), Fe29Co28Ni29Cu7Ti7, fabricated by casting, was investigated in detail. The as-cast Fe29Co28Ni29Cu7Ti7 HEA was composed of a primary fcc phase containing coherent dispersed L12 nanoprecipitates and trace amounts of a needle-like phase. The tensile yield strength (σ0.2), ultimate strength, and total elongation of the as-cast alloy are 917 MPa, 1060 MPa, and 1.8%, respectively. Following homogenization, the alloy having a single fcc phase shows a decrease of ∼ 55% in yield strength and a decrease of ∼ 36% in ultimate strength; however, the total elongation is increased from 1.8 to 52%. Saturation magnetization (Msat) is decreased from 111.54 to 110.34 Am2/kg, by contrast, coercivity (Hc) is increased from 266.65 to 966.89 A/m. The dissolution of precipitates and grain growth are mainly responsible for the changes in magnetic properties and mechanical behavior.