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Re-entrant relaxor ferroelectric behaviour is identified in BiFeO3–BaTiO3 ceramics, yielding anomalous thermal variations in structural distortion and functional properties.

Membrane electrode assemblies (MEAs) are critical components in influencing the electrochemical performance of high-temperature proton exchange membrane fuel cells (HT-PEMFCs). MEA manufacturing processes are mainly divided into the catalyst-coated membrane (CCM) and the catalyst-coated substrate (CCS) methods. For conventional HT-PEMFCs based on phosphoric acid-doped polybenzimidazole (PBI) membranes, the wetting surface and extreme swelling of the PA-doped PBI membranes make the CCM method difficult to apply to the fabrication of MEAs. In this study, by taking advantage of the dry surface and low swelling of a CsH5(PO4)2-doped PBI membrane, an MEA fabricated by the CCM method was compared with an MEA made by the CCS method. Under each temperature condition, the peak power density of the CCM-MEA was higher than that of the CCS-MEA. Furthermore, under humidified gas conditions, an enhancement in the peak power densities was observed for both MEAs, which was attributed to the increase in the conductivity of the electrolyte membrane. The CCM-MEA exhibited a peak power density of 647 mW cm−2 at 200 °C, which was ~16% higher than that of the CCS-MEA. Electrochemical impedance spectroscopy results showed that the CCM-MEA had lower ohmic resistance, which implied that it had better contact between the membrane and catalyst layer.

An unfilled tungsten bronze-structured ferroelectric ceramic, Ca0.28Ba0.72Nb2O6 (CBN28), has been doped with Y3+ to produce ceramics with a nominal composition, (Ca0.28Ba0.72)1-3w/2YwNb2O6 [0 ≤ w ≤ 0.05]. The substitution of Y3+ for Ca2+/Ba2+, and consequent additional vacancy formation, is assumed to occur on the A1/A2 sites. This resulted in a minor reduction of the c lattice parameter, and unit cell volume. For undoped CBN28, there was a slightly diffuse relative permittivity-temperature (εr-T) peak at 268 ⁰C. The peak became much broader for sample compositions w = 0.04 and 0.05 and the peak temperature showed a level of frequency dependence consistent with weak relaxor behaviour. The polarisation-electric field loops became narrower for samples w = 0.04 and 0.05, corresponding to a reduction in remnant polarisation value, from 2.4 to 0.8 µC cm-2 (30 kV cm-1). The Y doped ceramics exhibited stable relative permittivity over a wide temperature range, the variation being within ± 15% of the median value from 36 ⁰C to 218 ⁰C for w = 0.05, when measured at 1 kHz. Consequently, we suggest that A site donor-doping and aliovalent B site doping of CBN holds potential for industry standard, temperature stable, high temperature dielectrics (ɛr ≥ 500 ± 15% from - 55 to 250+ ⁰C).

The evolution of a submarine landslide is a very complicated process due to slurry–water interactions. Most previous studies have focused on debris flows or turbidity currents independently. Little research has been conducted on the processes of transformation from debris flows into turbidity currents. Moreover, the underlying mechanical mechanisms of these transformation processes are not well understood. In this study, we aimed to better understand these mechanisms by simulating submarine landslide transportation processes using computational fluid dynamics. In the numerical models, the two-phase mixture module was adopted to mimic the interactions of the slurry with the ambient water, which we validated through a dam-break case. Here, the rheological behaviors of the slurries are described using the Herschel–Bulkley model. A formula for transformation rates is best fitted through a case series of debris flows. In particular, the activation stress is expressed by the dynamic pressure at the moment when the slurry starts to mobilize, which is fitted as a coefficient 6.55 × 10−5 times the shear strength. Then, two coefficients in the formula of the transformation rate are fitted as 1.61 and 0.26, respectively, based on the cases of debris flows, considering their different initial thicknesses, levels of slurry consistency and slope angles. Finally, in a real-scale debris flow case study, we demonstrate that the slurry is fully transformed before it is deposited. The expected outcome, the mechanical theory, the activation stress and the transformation rate would be applied to assess the influence area of the realistic turbidity currents and their harm to the subsea environment.

The variations in the reference evapotranspiration (ET0) are closely related to meteorological factors. The purpose of this study is to explore the relationships between the meteorological factors and the ET0. Based on meteorological data from 26 meteorological stations in the Yiluo River Basin (YLRB) and its surrounding areas from 1958 to 2020, in this study, the temporal and spatial variations and driving factors of the ET0 in the YLRB are investigated. The results are as follows. Spatially, the annual ET0 decreases from the northeast to the southwest in the YLRB. Temporally, the annual ET0 exhibits a fluctuating decreasing trend rather than a monotonic decreasing trend during the entire period. The trend of the ET0 contains two mutation points, in 1972 and 1994. Thus, the research period can be divided into three periods. It is concluded that the variations in the ET0 are the most sensitive to the relative humidity, but the driving factor that contributes the most to the variations in the ET0 is the wind speed. The driving factors are closely related to the rates of relative change of the meteorological factors.

Climatic factors are the main drivers that change net primary productivity (NPP). We chose the Yiluo River Basin as the study area to investigate the response of NPP to climatic factors in the Yellow River’s middle reaches. The temporal and spatial distribution of net primary productivity and the trend change of slope in the basin from 2000 to 2020 are analyzed. In addition, we analyzed the correlation between the NPP and climatic factors (precipitation and temperature) and the time-lag effect. The results show that 1) the annual average NPP in the basin is 556.4 gC/m2/a, the maximum value that occurred in 2019. Most of the NPP’s mutation points in the basin’s forest appeared in 2004, while the NPP’s mutation points in arable land mostly appeared in 2008 and 2009. 2) The slope trend analysis result of NPP from 2000 to 2020 shows that the NPP in 67.88% of the basin shows a significant increasing trend, 3.8% of the basin shows a significant decrease, and the other area show no significant change. 3) The correlation analysis between NPP and climatic factors shows a positive correlation between precipitation and NPP in 62.3% of the basin and a positive correlation between air temperature and NPP in 62.5%. The response of NPP to precipitation and temperature in the basin has different degrees of a time-lag effect. The NPP has a time-lag effect on precipitation in 44.8% of the basin, and its mean lag time is 8 days. NPP has a time-lag effect on temperature in 55.7% of the basin, and its mean lag time is 1 day. This study is beneficial to understanding the influence of climatic factor change on vegetation activities in the Yiluo River Basin. Our study illustrates the significance of time lag in analyzing the relationship between NPP and climatic factors. Furthermore, it provides support for scientific vegetation regulation and allocation, as well as adaptation to climate change in areas similar to the Loess Plateau, based on the lag time distribution corresponding to different vegetation types in different regions of the Yiluo River Basin. After that, these areas’ water resources will be fully utilized by vegetation, and ecological restoration could be accelerated.

We report an in-situ synchrotron X-ray diffraction study of K0.5Bi0.5TiO3-BiFeO3-PbTiO3 ceramics, which exhibit a Tc of around 450 °C. The electromechanical actuation mechanisms comprise contributions from coexisting tetragonal and rhombohedral phases. The tetragonal {200} grain family exhibited the highest effective lattice strain, up to 8.2 × 10−3 at 5 kV/mm. Strong strain anisotropy in the tetragonal phase and field-induced intergranular stresses facilitate a partial transformation from tetragonal (high strain anisotropy) to rhombohedral (low strain anisotropy) at high electric field levels, with an average linear transformation strain of -1.54 × 10-3. The domain switching behavior was effectively enhanced in both tetragonal and rhombohedral phases after the phase transformation, due to the release of intergranular stress. This observed self-adapting mechanism in tuning intergranular stress through partial phase switching in the morphotropic KBT-BF-PT composition with large lattice distortion could also be exploited in other perovskite systems in order to achieve high performance high temperature piezoelectric ceramics.

Vaccination is an effective strategy to fight COVID-19. However, the effectiveness of the vaccine varies among different populations in varying immune effects. Neutralizing antibody (NAb) level is an important indicator to evaluate the protective effect of immune response after vaccination. Lateral flow immunoassay (LFIA) is a rapid, safe and sensitivity detection method, which has great potential in the detection of SARS-CoV-2 NAb. In this study, a fluorescent beads-based lateral flow immunoassay (FBs-LFIA) and a latex beads-based LFIA (LBs-LFIA) using double antigen sandwich (DAS) strategy were established to detect NAbs in the serum of vaccinated people. The limit of detection (LoD) of the FBs-LFIA was 1.13 ng mL

Pyriproxyfen is an insect growth regulator that is widely used in public health and pest control in agriculture. Our previous studies have shown that trace amounts of pyriproxyfen in the environment can cause serious toxic effects in the non-target insect silkworm, including failing to pupate, metamorphose and spin cocoons. However, it is unknown why pyriproxyfen not only has no lethal effects on fifth instar larvae but also tend to increase their body weight. The midgut is the main digestive organs of the silkworm, our results showed that the residual of pyriproxyfen in the silkworm at 24 h after 1 × 10

High relative permittivity, er, over a very wide temperature range, −65 °C to 325 °C, is presented for ceramics designed to be compatible with base metal electrode multilayer capacitor manufacturing processes. We report a ≥ 300 °C potential Class II capacitor material, free from Bi or Pb ions, developed by doping Sr2NaNb5O15 with Ca2+, Y3+ and Zr4+ ions, according to the formulation Sr2−2zCazYzNaNb5-zZrzO15. For sample composition z = 0.025, er values are 1565 ± 15 % (1 kHz) from −65 °C to 325 °C. At a slightly higher level of doping, z = 0.05, er values are 1310 ± 10 % from −65 °C to 300 °C. Values of the dielectric loss tangent, tanδ are ≤ 0.025 from −60 °C to 290 °C, for z = 0.025, with tanδ increasing to 0.035 at 325 °C. Microstructural analyses exclude core-shell mechanisms being responsible for the flattening of the er –T response.

Previous studies on the cut quality of sugarcane stalks have mainly focused on external factors. However, the effects of internal factors on the cut quality have rarely been studied. In this study, the influence of internal and external factors on the cut quality were considered. Numerical finite element simulations and an experimental design were utilised to investigate the influences of the internal and external factors on the cut quality. The numerical model was validated using experimental cutting tests and based on a theoretical analysis. The optimum combination of cutting system parameters was investigated using an orthogonal test. The cut quality of the optimal combination was verified based on experiments. From the results, it was seen that the cutting bevel angle plays a significant role in affecting the cutting force, whereas machine forward speed (within the range 0.4–0.6 m s−1) and rotational speed (within the range 650–750 rpm) had no noticeable influence on cutting force. The optimal combination obtained by the orthogonal experiment was a cutting bevel angle of 30°, forward speed of 0.4 m s−1, and cutter rotational speed of 650 rpm. The optimised parameter combination produced an improved quality of cut in a cutting test. The damage mechanisms of sugarcane arising from internal factors were also investigated. This study provides basic information for the design of a base cutter for sugarcane harvesting.

Cervical cancer is a serious threat to women's health due to malignant tumours, and early detection can greatly reduce mortality. In this paper, cervical tissue was used as the research object, and Raman spectroscopy analysis of cervical inflammation and precancerous tissues was used to detect cervical cancer. This provides a clinical basis for the use of Raman spectroscopy in analysis of cervical precancerous lesions. In this study, the actual Raman spectrum signal of precancerous cervical tissue was collected, and the PLS and Relief methods were used to extract the signal characteristics of the spectrum. Then, we established and compared KNN and ELM classification models and finally achieved the early diagnosis of cervical cancer. This experiment designed a novel feature fusion method in feature extraction, and we used the first and second derivative features that reflect more peak details of the original spectrum for fusion. The accuracy rate of KNN without feature fusion is 88.17%, and the accuracy rate after fusion is 93.55%. The accuracy rate of ELM without feature fusion is 90.81%, and the accuracy rate after fusion is 93.51%. The results show that the accuracy of feature fusion has been improved to a certain extent, and this method is expected to be used as a new method of spectral data fusion.

Population and water withdrawal data sets are currently faced with difficulties in collecting, processing and verifying multi-source time series, and the spatial distribution characteristics of long series are also relatively lacking. Time series is the basic guarantee for the accuracy of data sets, and the production of long series spatial distribution is a realistic requirement to expand the application scope of data sets. Through the time-consuming and laborious basic processing work, this research focuses on the population and water intake time series, and interpolates and extends them to specific land uses to ensure the accuracy of the time series and the demand of spatially distributed data sets. This research provides a set of population density and water intensity products from 1960 to 2020 distributed to the administrative units or the corresponding regions. The data set fills the gaps in the multi-year data set for the accuracy of population density and the intensity of water withdrawal.

BiFeO3–BaTiO3 (BF–BT) ceramics exhibit great potential for diverse applications in high temperature piezoelectric transducers, temperature-stable dielectrics and pulsed-power capacitors. Further optimization of functional properties for different types of applications can be achieved by modification of processing parameters or chemical composition. In the present work, the influence of pentavalent niobium substitution for trivalent ferric ions on the structure, microstructure and dielectric properties of 0.7BF–0.3BT ceramics was investigated systematically. Doping with niobium led to incremental reductions in grain size (from 7.0 to 1.3 µm) and suppression of long-range ferroelectric ordering. It was found that core-shell type microstructural features became more prominent as the Nb concentration increased, which were correlated with the formation of distinct peaks in the dielectric permittivity–temperature relationship, at ~470 and 600 °C, which were attributed to the BT-rich shell and BF-rich core regions, respectively. Nb-doping of BF–BT ceramics yielded reduced electronic conductivity and dielectric loss, improved electrical breakdown strength and enhanced dielectric energy storage characteristics. These effects are attributed to the charge compensation of pentavalent Nb donor defects by bismuth vacancies, which suppresses the formation of oxygen vacancies and the associated electron hole conduction mechanism. The relatively high recoverable energy density (Wrec = 2.01 J cm−3) and energy storage efficiency (η = 68%) of the 0.7BiFeO3–0.3BaTiO3 binary system were achieved at 75 °C under an electric field of 15 kV mm−1. This material demonstrates the greatest potential for applications in energy storage capacitors and temperature-stable dielectrics.

Links between residual stress and domain switching in porous barium titanate ceramics were investigated using synchrotron X-ray diffraction as a function of an applied electric field. Barium titanate with highly aligned pores (with pore fraction = 0.52) was manufactured by freeze casting and compared with barium titanate produced via conventional pressing and sintering (with = 0.06). The domain switching fraction in the freeze cast ceramic was approximately double that of the low porosity barium titanate at a field of 3 kV/mm, attributed to a reduction in the residual stress from 70 MPa to 40 MPa with increasing pore fraction. Whilst extrinsic domain switching was enhanced, the intrinsic lattice strain contribution to the piezoelectric properties was slightly reduced in the freeze cast barium titanate compared to the conventionally processed ceramic. These results point towards novel methods for engineering the functional properties of piezoelectric ceramics in the future.

Conventional triaxial strength criteria are important for the judgment of rock failure. Linear, parabolic, power, logarithmic, hyperbolic, and exponential equations were, respectively, established to fit the conventional triaxial compression test data for 19 types of rock specimens in the Mohr stress space. Then, a method for fitting the failure envelope to all common tangent points of each two adjacent Mohr’s circles (abbreviated as CTPAC) was proposed in the Mohr stress space. The regression accuracy of the linear equation is not as good as those of the nonlinear equations on the whole, and the regression uniaxial compression strength (σc)r, tensile strength (σt)r, cohesion cr, and internal frictional angle φr predicted by the regression linear failure envelopes with the method for fitting the CTPAC in the Mohr stress space are close to those predicted in the principal stress space. Therefore, the method for fitting CTPAC is feasible to determine the failure envelopes in the Mohr stress space. The logarithmic, hyperbolic, and exponential equations are recommended to obtain the failure envelope in the Mohr stress space when the data of tensile strength (σt)t are or are not included in regression owing to their higher R2, less positive x-intercepts, and more accurate regression cohesion cr. Furthermore, based on the shape and development trend of the nonlinear strength envelope, it is considered that when the normal stress is infinite, the total bearing capacity of rock tends to be a constant after gradual increase with decreasing rates. Thus, the hyperbolic equation and the exponential equation are more suitable to fit triaxial compression strength in a higher maximum confining pressure range because they have limit values. The conclusions can provide references for the selection of the triaxial strength criterion in practical geotechnical engineering.

Atomically dispersed transition metal active sites have emerged as one of the most important fields of study because they display promising performance in catalysis and have the potential to serve as ideal models for fundamental understanding. However, both the preparation and determination of such active sites remain a challenge. The structural engineering of carbon- and nitrogen-coordinated metal sites (M-N-C, M = Fe, Co, Ni, Mn, Cu, etc.) via employing new heteroatoms, e.g., P and S, remains challenging. In this study, carbon nanosheets embedded with nitrogen and phosphorus dual-coordinated iron active sites (denoted as Fe-N/P-C) were developed and determined using cutting edge techniques. Both experimental and theoretical results suggested that the N and P dual-coordinated iron sites were favorable for oxygen intermediate adsorption/desorption, resulting in accelerated reaction kinetics and promising catalytic oxygen reduction activity. This work not only provides efficient way to prepare well-defined single-atom active sites to boost catalytic performance but also paves the way to identify the dual-coordinated single metal atom sites.

In situ, spatially-resolved synchrotron X-ray diffraction was utilized to investigate the electric field-induced heterogenous phase transformation of nonergodic relaxor 0.93Na1/2Bi1/2TiO3-0.07BaTiO3 ceramics. A Cu electrode was coated on one surface of a rectangular sample by aerosol deposition (AD), while a Pt layer was deposited on the opposite surface by sputter deposition. It is anticipated that a different stress state and/or domain morphology should occur on the AD deposited Cu electrode side due to the particle impact-consolidation deposition process. Under an electric field, different sample regions, i.e., AD, Middle, and Sputter sides, showed systematic changes in the relaxor to ferroelectric phase transition behavior. In particular, most grains transformed at a sub-coercive field of 0.8 kV/mm, while the majority of the grains only appeared to undergo transitions at a higher field (2.4 kV/mm). Also, the tetragonal phase became the dominant structure at higher field levels. Importantly, both and grains undergo phase switching at lower fields in the region close to the AD-processed layer. The study indicates that the AD process-induced stress can facilitate the electric field-induced relaxor to ferroelectric phase transition, i.e., the AD Cu side showed more significant lattice strain and domain texture than the sputter Pt side.

BiFeO

As a promising thermoelectric and semiconducting material, the stability of two-dimensional tin selenide (SnSe) under harsh environments is significant for its practical applications. Here, focusing on the key procedures in the device fabrication process, we report the anisotropic structural and electrical stabilities of SnSe under an alkaline environment and mechanical strain. Due to the anisotropic mechanical properties, the SnSe flakes can naturally form long-straight {011} edge planes during the mechanical exfoliation process. Such a cleavage tendency provides an effective crystal orientation identification method to uncover the orientation-dependent properties. We find that the single-crystalline SnSe flakes experience an anisotropic degradation process with the preferable {011} dissolution planes in the alkaline environment and can be gradually transformed to be polycrystalline consisting of SnSe

The prevention of the COVID-19 pandemic is highly complicated by the prevalence of asymptomatic and recurrent infection. Many previous immunological studies have focused on symptomatic and convalescent patients, while the immune responses in asymptomatic patients and re-detectable positive cases remain unclear. Here we comprehensively analyzed the peripheral T-cell receptor (TCR) repertoire of 54 COVID-19 patients in different courses, including asymptomatic, symptomatic, convalescent, and re-detectable positive cases. We identified a set of V–J gene combinations characterizing the upward immune responses through asymptomatic and symptomatic courses. Furthermore, some of these V–J combinations could be awakened in the re-detectable positive cases, which may help predict the risk of recurrent infection. Therefore, TCR repertoire examination has the potential to strengthen the clinical surveillance and the immunotherapy development for COVID-19.

Ferroptosis, first proposed in 2012, is an iron-dependent form of regulated cell death characterized by excessive polyunsaturated fatty acid oxidation. In the past decade, researchers have revealed the formation and mechanisms of ferroptosis. Cancer drug resistance can be reversed by ferroptosis induction, and inhibiting ferroptosis has been shown to block certain disease processes. As a result, several ferroptosis-targeting drugs have been developed. However, the first-generation ferroptosis-targeting agents remain hampered from clinical use, mainly due to poor selectivity and pharmacokinetics. The discoveries of FSP1, GCH1, and other potential ferroptosis-regulating pathways independent of Xc

The appearance and magnitude of the immune response and the related factors correlated with SARS-CoV-2 vaccination need to be defined. Here, we enrolled a prospective cohort of 52 participants who received two doses of inactivated vaccines (BBIBP-CorV). Their serial plasma samples (n = 260) over 2 months were collected at five timepoints. We measured antibody responses (NAb, S-IgG and S-IgM) and routine blood parameter. NAb seroconversion occurred in 90.7% of vaccinated individuals and four typical NAb kinetic curves were observed. All of the participants who seroconverted after the first dose were females and had relatively high prevaccine estradiol levels. Moreover, those without seroconversion tended to have lower lymphocyte counts and higher serum SAA levels than those who experienced seroconversion. The NAb titers in young vaccine recipients had a significantly higher peak than those in elderly recipients. S-IgG and S-IgM dynamics were accompanied by similar trends in NAb. Here, we gained insight into the dynamic changes in NAbs and preliminarily explored the prevaccine blood parameters related to the kinetic subclasses, providing a reference for vaccination strategies.

The existence of asymptomatic and re-detectable positive coronavirus disease 2019 (COVID-19) patients presents the disease control challenges of COVID-19. Most studies on immune responses in COVID-19 have focused on moderately or severely symptomatic patients; however, little is known about the immune response in asymptomatic and re-detectable positive (RP) patients. Here we performed a comprehensive analysis of the transcriptomic profiles of peripheral blood mononuclear cells (PBMCs) from 48 COVID-19 patients which included 8 asymptomatic, 13 symptomatic, 15 recovered and 12 RP patients. The weighted gene co-expression network analysis (WGCNA) identified six co-expression modules, of which the turquoise module was positively correlated with the asymptomatic, symptomatic, and recovered COVID-19 patients. The red module positively correlated with symptomatic patients only and the blue and brown modules positively correlated with the RP patients. The analysis by single sample gene set enrichment analysis (ssGSEA) revealed a lower level of IFN response and complement activation in the asymptomatic patients compared with the symptomatic, indicating a weaker immune response of the PBMCs in the asymptomatic patients. In addition, gene set enrichment analysis (GSEA) analysis showed the enrichment of TNFα/NF-κB and influenza infection in the RP patients compared with the recovered patients, indicating a hyper-inflammatory immune response in the PBMC of RP patients. Thus our findings could extend our understanding of host immune response during the progression of COVID-19 disease and assist clinical management and the immunotherapy development for COVID-19.

The effects of pre-strain on hydrogen embrittlement of 304L K-TIG welded joint were investigated. As pre-strain of joint increased, fracture location of hydrogen-charged joint changed from weld metal to base metal. In low prestrained joints, fracture may be initiated at the sites of clustered dislocations due to hydrogen in weld metal with a high density of pre-existing dislocations. In high prestrained joints, some regions in base metal suffered severe strain-induced α′ martensitic transformation due to Ni depletion bands and cracking occurred at phase boundaries where may provide more sites for the accumulation of hydrogen atoms and dislocations.

Fe3O4 nanoparticle-encapsulating N-doped porous carbon was synthesized. Owing to the large specific surface area, hierarchical porous structure, and sufficient number of active sites from the graphitic carbon wrapped Fe3O4 NPs as well as the joint effect with Fe-Nx moieties, the as-prepared 2D-Fe3O4@FeNC-700 electrocatalyst exhibits exceptional performance in Zn-air batteries.

The existence of asymptomatic and re-detectable positive COVID-19 patients presents the disease control challenges of COVID-19. Most studies on immune response of COVID-19 have focused on the moderately or severely symptomatic patients, however little is known about the immune response in asymptomatic and re-detectable positive patients. Here we performed a comprehensive analysis of the transcriptomic profiles of PBMCs from 48 COVID-19 patients which include 8 asymptomatic, 13 symptomatic, 15 recovering and 12 RP patients. Our analysis revealed a down-regulation of IFN response and complement activation in the asymptomatic patients compared with the symptomatic, indicating a weaker immune response of the PBMCs in the asymptomatic patients. In addition, we observed a lower expression of the cytokines and chemokines in the PBMC of asymptomatic and symptomatic patients. In contrast, the cytokines and chemokines level in the RP patients are higher than the recovering. GSEA analysis showed the enrichment of TNFa/NF-κB and influenza infection in the RP patients compared with the recovering patients, indicating a flu-like, hyper-inflammatory immune response in the PBMC of RP patients. Thus our findings could extend our understanding of host immune response during the progression COVID-19 disease and help the clinical management and the immunotherapy development for COVID-19.

IntroductionHip fracture is a common and serious emergency in the elderly, it is associated with severe pain, significant postoperative morbidity and mortality. Featuring peripheral nerve block in Enhanced recovery after surgery (ERAS) pathway may have significantly effect on shortening length of hospital stay, decreasing complications and costs, particular in improvement in dynamic pain and reducing the use of opioid. Pericapsular Nerve Group Block(PENG), suggested by Arango et al, may provide a effective blockade to the articular branches of the anterior hip joint,which innervate the most section of the hip capsule richly, with a potential motor-sparing effect.The purpose of this trail is to investigate whether PENG is effective to enhanced recovery in elderly patients with hip fracture.Methods and analysisThis study will be a single centre,randomized, parallel controlled, double-blind trail. 92 elderly patients scheduled for hip fracture surgery will be divided into two groups randomly to receive ultrasound-guided PENG block or ultrasound-guided femoral nerve(FN) block. The primary outcome will be compare the quality of recovery-15(QoR-15) score at 24h postoperatively between two groups.The secondary outcomes include the strength of quadriceps, the visual analogue scale(VAS) at rest and on movement, the total morphine consumption, the rescue analgesic, the first time of postoperative out-of-bed mobilization, the complications.Ethics and disseminationThis study has been approved by the Medical Science Research Ethics Committees of The First Affiliated Hospital of Guangzhou University of Chinese Medicine on 15 December 2020 (Reference K2020-110). The results of this study will be published in peer-reviewed international journals.Trial registration numberChiCTR2100042341.

To systematically explore potential biomarkers which can predict disease severity in COVID-19 patients and prevent the occurrence or development of severe COVID-19, the levels of 440 factors were analyzed in patients categorized according to COVID-19 disease severity; including asymptomatic, mild, moderate, severe, convalescent and healthy control groups. Factor candidates were validated by ELISA and functional relevance was uncovered by bioinformatics analysis. To identify potential biomarkers of occurrence or development of COVID-19, patient sera from three different severity groups (moderate, severe, and critical) at three time points (admission, remission, and discharge) and the expression levels of candidate biomarkers were measured. Eleven differential factors associated with disease severity were pinpointed from 440 factors across 111 patients of differing disease severity. The dynamic changes of GDF15 reflect the progression of the disease, while the other differential factors include TRAIL R1, IGFBP-1, IGFBP-4, VCAM-1, sFRP-3, FABP2, Transferrin, GDF15, IL-1F7, IL-5Rα, and CD200. Elevation of white blood cell count, neutrophil count, neutrophil-lymphocyte ratio (NLR), Alanine aminotransferase and Aspartate aminotransferase, low lymphocyte and eosinophil counts in the severe group were associated with the severity of COVID-19. GDF15 levels were observed to be associated with the severity of COVID-19 and the dynamic change of GDF15 levels was closely associated with the COVID-19 disease progression. Therefore, GDF15 might serve as an indicator of disease severity in COVID-19 patients.

In this paper, we provide the first direct evidence of enhanced domain mobility in porous barium titanate, compared to a dense sample of the same composition, facilitated by a relaxation in intergranular stress. We demonstrate that porosity can act to unclamp domains in ferroelectric ceramics, increasing the extrinsic contribution to bulk piezoelectric properties, and providing a novel route for functional property engineering in the future. Porous barium titanate with highly aligned, anisometric pores and pore volume fraction, vp = 0.52, was fabricated by the freeze casting method; dense barium titanate (relative density, Ρrel = 0.94) was fabricated for comparison. High energy synchrotron X-ray diffraction experiments with in-situ electric field dependent measurements were used to investigate the residual stress, lattice strain and domain switching contributions to electrostrain in the porous and dense barium titanate ceramics. The domain switching fraction was calculated as a function of the applied electric field. Almost twice as many domains were observed to switch in the porous barium titanate compared to the dense material at 3 kV/mm (41.7% and 21.7%, respectively), which we attribute to the significant reduction in the intergranular stress due to the high volume of zero-stiffness pores. Using a micromechanical approach, the residual stress was estimated to be 70 MPa in the dense barium titanate at 3 kV/mm compared to 40 MPa in the porous material under the same electric field, reducing to 30 MPa and 10 MPa, respectively, in the remanent state. Whilst the fraction of domain switching was enhanced, the intrinsic contribution to the piezoelectric properties was slightly reduced in the porous barium titanate compared to the dense ceramic. The findings presented in this paper demonstrate that as well as providing a route to tailor application-specific effective bulk properties, compliant and low permittivity second phases can be used to engineer the behaviour of ferroelectric composites at the lattice and domain level. This broadens significantly the microstructural design space for ferroelectric composites, which are of particular interest for piezo- and pyroelectric sensors and energy harvesters, in the future.

The correlation between the out-of-plane stress and the in-plane stress is established based on the bending modified J-Q theory and the out-of-plane constraint parameter TZ. Accordingly, an improved J-QZ-M constraint theory is developed to characterize the crack-tip fields by taking into account opening- and bending-dominated deformations in the ligament of the clamped single edge notch tension (SE(T)) specimens. Three-dimensional elastic-plastic finite element analyses (FEA) with a wide range of in-plane and out-of-plane constraints are performed to validate the proposed approach. It is found that the proposed J-QZ-M constraint theory can effectively quantify the crack-tip fields of SE(T) specimens, and the constraint parameter QZ exhibits approximately load- and distance-independence until large scale yielding (LSY).

A coherent core-shell structure in 0.24BiFeO3-0.56K0.5Bi0.5TiO3-0.20PbTiO3 ceramics, with Tm around 385 °C, was revealed using a combination of characterisation methods including scanning and transmission electron microscopy. The core regions consist of a cubic matrix with minor monoclinic phase with limited coherence length, while the shell regions are a tetragonal phase with characteristic long-range ordered ferroelectric domain structures. The electric field-induced strains for both core and shell regions were investigated by conducting an in-situ poling study using high energy synchrotron X-ray diffraction (XRD). A methodology is developed to evaluate both intrinsic (lattice strain) and extrinsic (domain switching) contributions for each phase based on diffraction peak profile fitting for multiple reflections. It is shown that there were no significant variations in the cubic and tetragonal phase fractions under an electric field in the range from −6 to +6 kV mm−1. An irreversible strain ∼0.04% was attributed mainly to ferroelectric domain switching in the tetragonal shell regions, while a reversible lattice strain ∼0.12% was identified in the pseudo-cubic core, leading to significant levels of intra-granular stress. Strain anisotropy, dependent on the crystallographic orientation of different grain families, was also evident. Macroscopic strain measurements, conducted using a novel digital image correlation (DIC) method, demonstrated the formation of typical ‘butterfly’-type strain-electric field loops and were consistent with the total strain values calculated from the XRD results.

With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience (QoE) has made rate adaptation methods very attractive. In this paper, we propose a two-phase rate adaptation strategy to improve users' real-time video QoE. First, to measure and assess video QoE, we provide a continuous QoE prediction engine modeled by RNN recurrent neural network. Different from traditional QoE models which consider the QoE-aware factors separately or incompletely, our RNN-QoE model accounts for three descriptive factors (video quality, rebuffering, and rate change) and reflects the impact of cognitive memory and recency. Besides, the video playing is separated into the initial startup phase and the steady playback phase, and we takes different optimization goals for each phase: the former aims at shortening the startup delay while the latter ameliorates the video quality and the rebufferings. Simulation results have shown that RNN-QoE can follow the subjective QoE quite well, and the proposed strategy can effectively reduce the occurrence of rebufferings caused by the mismatch between the requested video rates and the fluctuated throughput and attains standout performance on real-time QoE compared with classical rate adaption methods.

The effects of hydrogen on the mechanical properties of 304L keyhole tungsten inert gas welded joint were investigated in the study. The presence of hydrogen resulted in a significant decrease in the macroscopic ductility of the weld metal, and fracture may be initiated at the sites of clustered dislocations due to hydrogen atoms. Moreover, it is found that hydrogen may result in more severe loss in ductility and noticeable decrease in the flow stress and strength of the base metal, because of the interplay between the hydrogen atoms and strain-induced α′ martensite. Strain-induced α′ martensitic transformation and phase boundaries in the base metal may provide more sites for the accumulation of hydrogen and dislocations, leading to an appreciable decrease in the ductility and strength of the base metal.