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This paper proposes a convex time-optimal trajectory planning method for industrial robotic manipulators with jerk constraints. To achieve smooth and efficient trajectories, the square of the pseudo velocity profile is constructed using a cubic uniform B-spline, and a linear relationship is defined with the control points of the B-spline to preserve convexity in the pseudo states. Bi-linear and non-convex jerk constraints are introduced in the optimization problem, and a convex restriction method is applied to achieve convexity. The proposed method is evaluated through three case studies: two contour following tasks and a pick-and-place task. Comparative optimization results demonstrate that the proposed method achieves time optimality and trajectory smoothness simultaneously in the reformulated and jerk-restricted optimization problem. The proposed method provides a practical approach to address the non-convexity of jerk constraints in trajectory optimization for industrial robotic manipulators. Note to Practitioners—This work was motivated by the challenge of generating smooth and time-optimal trajectories for industrial manipulators while considering jerk and dynamic constraints. Existing approaches typically use multi-objective methods that treat jerk constraints as soft constraints. In contrast, this work proposes a B-spline-based convex optimization method that treats jerk constraints as hard constraints. Three case studies are conducted, involving butterfly-type, door-type and ‘OPTEC’-type paths, with the UR5 cooperative robot. The numerical and experimental results demonstrate that the proposed method sacrifices some time optimality to achieve trajectory smoothness and computational efficiency due to the convex restriction reformulation of the jerk constraints. Moreover, the proposed method is applicable to general industrial manipulators. Supplementary video is available at https://youtu.be/gVz5IuPKD-o.

I. Introduction "Data is the lifeblood of the modern global economy. Digital trade and cross-border data flows are expected to continue to grow faster than the overall rate of global [...]

Background: Stem cell-released exosomes (EXs) have shown beneficial effects on regenerative diseases. Our previous study has revealed that EXs of endothelial progenitor cells (EPC-EXs) can elicit favorable effects on endothelial function. EXs may vary greatly in size, composition, and cargo uptake rate depending on the origins and stimulus; notably, EXs are promising vehicles for delivering microRNAs (miRs). Since miR-210 is known to protect cerebral endothelial cell mitochondria by reducing oxidative stress, here we study the effects of miR-210-loaded EPC-EXs (miR210-EPC-EXs) on ischemic brain damage in acute ischemic stroke (IS).Methods: The miR210-EPC-EXs were generated from EPCs transfected with miR-210 mimic. Middle cerebral artery occlusion (MCAO) surgery was performed to induce acute IS in C57BL/6 mice. EPC-EXs or miR210-EPC-EXs were administrated via tail vein injection 2 hrs after IS. To explore the potential mechanisms, inhibitors of the vascular endothelial growth factor receptor 2 (VEGFR2)/PI3 kinase (PI3K) or tyrosine receptor kinase B (TrkB)/PI3k pathways were used. The brain tissue was collected after treatments for infarct size, cell apoptosis, oxidative stress, and protein expression (VEGFR2, TrkB) analyses on day two. The neurological deficit score (NDS) was evaluated before collecting the samples.Results: 1) As compared to EPC-EXs, miR210-EPC-EXs profoundly reduced the infarct volume and improved the NDS on day two post-IS. 2) Fewer apoptosis cells were detected in the peri-infarct brain of mice treated with miR210-EPC-EXs than in EPC-EXs-treated mice. Meanwhile, the oxidative stress was profoundly reduced by miR210-EPC-EXs. 3) The ratios of p-PI3k/PI3k, p- VEGFR2/VEGFR2, and p-TrkB/TrkB in the ipsilateral brain were raised by miR210-EPC-EXs treatment. These effects could be significantly blocked or partially inhibited by PI3k, VEGFR2, or TrkB pathway inhibitors.Conclusion: These findings suggest that miR210-EPC-EXs protect the brain from acute ischemia- induced cell apoptosis and oxidative stress partially through the VEGFR2/PI3k and TrkB/PI3k signal pathways.

A photonic radar with real-time detection ability and multi-band agility is proposed and demonstrated. In the proposed scheme, a dual-polarization Mach-Zehnder modulator (DP-MZM) coupled by an optical pulse from mode locked laser (MLL) is used to implement baseband signal sampling and echo signal receiving in orthogonal polarization, independently. After extracting the baseband signal under optical sampling from partial output signal of DP-MZM, it is transformed to microwave signal, in which, by choosing specific harmonic mixing signal with bandpass filter at electronic transmitter, the up-conversion radar transmitting signal in expected band is obtained. Meanwhile, another partial of optical signal from DP-MZM is polarization demultiplexed to the optical reference signal and receiving signal by a polarization beam splitter. Then, the de-chirping of radar echo signal can be completed with a balanced photodetector for balanced detection the optical reference signal and receiving signal. By conducting the proof-of-concept experiments, the feasibility of the proposed system is verified in K-band with a range resolution 2.22 cm. Furthermore, the multi-band agility of radar can be realized with adjusting the passband of radar electronic transmitter.

An integrated system comprising a commercial high-performance liquid chromatography HPLC (except autosampler) equipped with an external multichannel autofeeding module was developed to accomplish interference-free separation and kinetic tracking for the H2O2–thiourea reaction, which is proposed as a lab experiment for students who have the background of chemical kinetics. Compared to conventional HPLC, the proposed system: (i) provides a similar pedagogical purpose, where students’ knowledge in chemistry can be strengthened and improved and (ii) enables online species tracking and kinetic analysis of reactions with the spectral overlap of multiple species, and other interference factors such as turbidity caused by precipitation formation, bubble requirement, or external excitation light for photocatalysis. Additionally, automation of the proposed equipment allows for saving labor and high efficiency. Based on the reliability and accuracy of the proposed system, different species including reactants, intermediates, and products were simultaneously tracked during thiourea oxidation. Both kinetic curves of multiple species and kinetic parameters obtained provide lots of reliable data for fitting and mechanistic analysis. Because the H2O2–thiourea reaction as a lab experiment successfully performed by students with this technology has proven its operability for undergraduates majoring in chemistry, this proposed method is easy to extend to environmental science, pharmacokinetics, and other fields.

It is supposed that ultra-reliable low latency communication (uRLLC) would continue to evolve in the future sixth generation (6G) network, to provide enhanced capability towards extreme connectivity, with the aid of well established multiple-input multiple-output (MIMO) technology. Since the latency constraint can be represented equivalently by the blocklength of a codeword, channel coding theory at a finite blocklength plays an important role in theoretic analysis of uRLLC. Based on Polyanskiy’s and Yang’s asymptotic results on maximal achievable rate, we first derive the proximate closed-form expressions for the expectation and variance of channel dispersion. Then, the upper bound of average maximal achievable rate is obtained for massive MIMO systems under ideal independent and identically distributed fading channels. Since almost all the fundamental parameters, including the spatial degree-of-freedom (DoF), are considered, this expression can be viewed as a performance bound of the spatiotemporal two-dimension channel coding to some extent. Moreover, it is shown by simulation and analysis, as the DoF goes to infinity, MIMO systems reveal a nature of deterministic transmission, since the average maximal achievable coding rate per antenna can be achieved at each transmission. In this case, the inversely proportional law observed therein implies that the blocklength in the time domain can be further shortened at the expense of spatial DoF. This exchangeability of space and time, to support a given coding rate, paves a solid and feasible road for us to further reduce latency in 6G uRLLC.

Intelligent reconfigurable surface (IRS) becomes a promising technology for improving spectrum efficiency and reducing the energy consumption in the next-generation networks. To reap the passive beamforming gain of IRS, accurate channel estimation is essentially required. However, the existing channel estimation methods for the IRS-assisted orthogonal frequency division multiplexing (OFDM) systems suffer from serious performance loss, due to using the least-squares (LS) estimator and ignoring the channel sparsity in the time domain. Another drawback of the existing methods is that the channel estimation and data detection are separated from each other so that any inaccurate channel estimation would cause an error accumulation problem for the data detection. To overcome these drawbacks, we propose a novel joint sparse channel estimation and data detection method for the IRS-assisted OFDM systems. The novelties of the proposed method are twofold: i) present a new common sparse representation model for the joint channel estimation and data detection, which can utilize the common channel sparsity between the pilots and data streams to significantly improve the channel estimation performance and reduce the training overhead; and ii) propose an efficient variational Bayesian inference (VBI) framework to simultaneously perform the Bayesian inference for the sparse channel recovery and data detection, where the coupling effect caused by the reflection pattern is trickly evaded by adopting an additional column-independent factorization. Besides exploiting the common sparsity for the channel estimation and data detection, the proposed method also avoids using the LS estimator, and thus its performance can be greatly enhanced. Simulation results verify the superiority of the proposed method.

• The necessity and progress in selective laser melting of Mg alloys are elucidated. • Defect formation mechanism and properties characteristics are systematically discussed. • The achievements in optimizing performance based on the process and material are comprehensively reviewed. • The future challenges and valuable suggestions on selective laser melting of Mg alloys are indicated. Selective laser melting (SLM), as a rapid prototyping technology, has been widely used to manufacture high-performance metal components with complex structures, which vitally provides a broad platform for the development and application of magnesium alloys. However, the poor laser formability of magnesium alloys has deleterious consequences in the application of SLM processing. This paper discusses the defect formation mechanisms during the SLM process and summarizes characteristics in terms of mechanical properties, oxidation and corrosion resistance. Current optimization schemes are reviewed from both macro and micro perspectives. Firstly, the relationship between process parameters and formability and material properties is clarified, and advanced optimization methods of the design of experiments, physical models, and machine learning are evaluated. Secondly, the effects of alloying elements, composite reinforcement, and post-treatment on the microstructure and properties of the SLMed magnesium alloy are reviewed. Finally, the future application development prospects are envisaged based on the comprehensive review. This work is significantly helpful to a better scientific understanding of SLMed magnesium alloy and puts forward some meaningful guiding opinions for the future work of magnesium alloy manufacturing. [ABSTRACT FROM AUTHOR]

Space nuclear reactors are becoming popular in deep space exploration owing to their advantages of high-power density and stability. Following the fourth-generation nuclear reactor technology, a conceptual design of the dual drum-controlled space molten salt reactor (D2-SMSR) is proposed. The reactor concept uses molten salt as fuel and heat pipes for cooling. A new reactivity control strategy that combines control drums and safety drums was adopted. Critical physical characteristics such as neutron energy spectrum, neutron flux distribution, power distribution and burnup depth were calculated. Flow and heat transfer characteristics such as natural convection, velocity and temperature distribution of the D2-SMSR under low gravity conditions were analyzed. The reactivity control effect of the dual-drums strategy was evaluated. Results showed that the D2-SMSR with a fast spectrum could operate for 10 years at the full power of 40 kWth. The D2-SMSR has a high heat transfer coefficient between molten salt and heat pipe, which means that the core has a good heat-exchange performance. The new reactivity control strategy can achieve shutdown with one safety drum or three control drums, ensuring high-security standards. The present study can provide a theoretical reference for the design of space nuclear reactors.

Escherichia coliK1 (EC-K1) can bypass the blood–brain barrier (BBB) and cause meningitis. Excitingly, we find the “dead EC-K1” can safely penetrate the BBB because they retain the intact structure and chemotaxis of the live EC-K1, while losing their pathogenicity. Based on this, we develop a safe “dead EC-K1”-based drug delivery system, in which EC-K1 engulf the maltodextrin (MD)-modified therapeutics through the bacteria-specific MD transporter pathway, followed by the inactivation via UV irradiation. We demonstrate that the dead bacteria could carry therapeutics (e.g., indocyanine green (ICG)) and together bypass the BBB after intravenous injection into the mice, delivering ∼3.0-fold higher doses into the brain than free ICG under the same conditions. What is more, all mice remain healthy even after 14 days of intravenous injection of ∼109CFU of inactive bacteria. As a proof of concept, we demonstrate the developed strategy enables the therapy of bacterial meningitis and glioblastoma in mice.

Artificial camouflage has garnered long-standing interest in both academia and industry. The metasurface-based cloak has attracted much attention due to the powerful capability of manipulating the electromagnetic wave, convenient multifunctional integration design, and easy fabrication. However, existing metasurface-based cloaks tend to be passive and of single function and monopolarization, which cannot meet the requirement of applications in ever-changing environments. So far, it is still challenging to realize a reconfigurable full-polarization metasurface cloak with multifunctional integration. Herein, we proposed an innovative metasurface cloak, which can simultaneously realize dynamic illusion effects at lower frequencies (e.g., 4.35 GHz) and specific microwave transparency at higher frequencies (e.g., X band) for communication with the outside environment. These electromagnetic functionalities are demonstrated by both numerical simulations and experimental measurements. The simulation and measurement results agree well with each other, indicating that our metasurface cloak can generate various electromagnetic illusions for full polarizations as well as a polarization-insensitive transparent window for the signal transmission to enable the communication between the cloaked device and the outside environment. It is believed that our design can offer powerful camouflage tactics to address the stealth problem in ever-changing environments.

Study Design: Retrospective study.Objectives: To analyze the change in acetabular anteversion (AA) after lumbar pedicle subtraction osteotomy (PSO) in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis who have already undergone total hip arthroplasty (THA).Methods: AS patients with thoracolumbar kyphosis following lumbar PSO from January 2005 to January 2020 were retrospectively reviewed. Only the patients performed with THA prior to the PSO were included. AA was measured on the full-length standing posterior-anterior radiographs using the ellipse method.Results: Twenty patients (34 hips) with a mean age of 36.8 years (range, 22 to 63 years) were included. After lumbar PSO, AA was reduced from 18.59° to 5.85° (P< 0.001). Postoperative change in AA was correlated with the spinal deformity correction. Additionally, the change in AA postoperatively was correlated with pelvic incidence (PI) (R = 0.346, P= 0.045). Although the postoperative change in sagittal vertical axis (SVA) was larger in the patients after L2 or L3 PSO (153.97 mm vs 70.03 mm, P= 0.006), no difference was found in the postoperative change in AA (12.83° vs 10.96°, P= 0.540) compared with the patients following L1 PSO.Conclusions: AA was significantly decreased following lumbar PSO and the postoperative change in AA was correlated with the magnitude of spinal deformity correction. Notably, the effect of osteotomy level on the postoperative change in AA was limited in the AS patients underwent 1-level PSO.

Intelligent reflecting surface (IRS) is deemed as a potential technology for future communications due to its adaptive enhancement for the propagation environment. To achieve the passive beamforming gain of IRS, accurate channel state information (CSI) is essential but practically challenging since its massive passive reflecting elements have no transmitting/receiving capability. This paper presents a new channel estimation problem formulation for IRS-assisted orthogonal frequency division multiplexing (OFDM) systems, where the channel sparsity is exploited in the time-domain. Considering the surfaces are physically close to each other, we further utilize the common sparsity among the different sub-surfaces and automatically cluster them into several groups by introducing a Dirichlet process (DP)-based clustering model. Then, a DP-based variational Bayesian inference (VBI) framework is proposed to jointly estimate the channel and cluster the sub-surfaces, which is expected to significantly improve the channel estimation performance. Moreover, a novel decoupling trick is combined into the VBI framework to efficiently handle the coupling effect brought by the reflection coefficients, as well as facilitate the Bayesian inference. Simulation results verify the effectiveness of the proposed channel estimation scheme and show its significant performance improvement over various benchmark schemes.

The performance of a recycling process for CO2capture and utilization of exhaust gas in the steelmaking plant was reported. A facility capable of capturing CO2at 3200 m3/h was established in the steelmaking plant, resulting in the CO2production of 50,000 t/a. The CO2concentration of the exhaust gas from the lime kiln increased from 25.0 to 99.8 vol.% using the comprehensive method of the pressure swing adsorption and cryogenic separation. The captured and purified CO2was successfully applied in the converter process by the top blowing and bottom blowing. The utilization of CO2was 3.5 m3/t through these two modes. After optimizing parameters of CO2–O2mixed top blowing, the value of [C] × [O] and the content of TFe in slag were reduced by 1.33 × 10−4and 1.27%, respectively, and the dephosphorization rate of the molten steel increased by 2.31%. For the CO2bottom blowing, the [N] content in the molten steel was significantly reduced by 5.7 × 10−6.

A microwave photonics radar with interference-suppressed high-resolution detection ability is proposed and experimentally demonstrated based on optical frequency quadrupling and coherent receiving de-chirping. Which is achieved by using a dual-parallel Mach-Zehnder modulator to perform base-band signal frequency quadrupling in transmitter, and an optical coherent receiver to realize balanced photonic in-phase/quadrature (I/Q) de-chirping of the broadband radar echoes in receiver. Thanks to the frequency multiplication, a wideband radar transmitting signal can be generated with low speed electron devices. Meanwhile, interference-free detection by suppressing undesired common-mode interferences and image frequency could be achieved with balanced photonic I/Q de-chirping broadband radar echoes. In the experiment, a photonics-based K-band radar with a bandwidth of 8 GHz is demonstrated, corresponding to a resolution better than 2.0 cm. In addition, the balanced photonic I/Q de-chirping receiver achieves an image-rejection ratio of 40.4 dB. The proposed radar detection system is a promising candidate in interference-suppressed high-resolution radar application.

Resilience can play an important role in enabling disadvantaged students to succeed academically. However, few studies in low-resource contexts have evaluated resilience as a process (including a child’s internal capabilities and external resources, like the internal capabilities of a child’s caregiver) and as an outcome (e.g., academic achievement). In the current study, we examined the associations among students’ self-reported internal capabilities, their external resources (e.g., caregivers’ internal capabilities), and their academic resilience (operationalized as performance on a math test). The study was conducted among 1609 primary and secondary school students in rural China using the Connor–Davidson Resilience Scale (CD-RISC) to measure internal capabilities. Student CD-RISC scores were positively associated with external resources including caregiver CD-RISC scores, maternal education level, high levels of perceived social support, recreational reading, and involvement in group-based activities at school. A one-point increase in students’ CD-RISC scores was associated with a 0.01 SD increase in math score (p< 0.001), and the math scores of students whose CD-RISC scores were in the bottom quartile were 0.18 SD lower than those of their peers (p< 0.01). High levels of perceived social support and recreational reading were also associated with academic resilience in the adjusted equation. Directions for future research and policy implications are discussed.

This paper proposes a compact and reconfigurable variable stiffness actuator (VSA) using disc spring which is named as SDS-VSA (symmetrical disc spring variable stiffness actuator). To enhance the actuator’s torque density, symmetric compression springs are integrated into the cam-roller-spring mechanism, and a disc spring combination design is employed instead of conventional springs. The disc spring configuration is tailored to achieve a broader stiffness range within a limited size, aligned with stiffness and dimensional requirements. Subsequently, the dynamics of the cam-roller-spring mechanism are derived. To tackle the challenge of strong coupling dynamics, a decoupled modeling method by introducing mismatched and matched disturbances is proposed. A back-stepping tracking controller and proportional-derivative (PD) controller with feedforward are proposed to track the link-side and stiffness motor-side trajectories, respectively. Tracking experiments under significant stiffness alteration are conduced to verify the performance of the prototype SDS-VSA.

To investigate the efficacy of combined immunosuppressive regimens of cyclosporine (CsA), tacrolimus (TAC), or cyclophosphamide (CTX) combined with steroids in the treatment of idiopathic membranous nephropathy (IMN).

Study Design: A retrospective study.Objective: To investigate the effect of pedicle subtraction osteotomy (PSO) level on the surgical outcomes in ankylosing spondylitis-related thoracolumbar kyphosis with the same curve pattern.Methods: ankylosing spondylitis (AS) patients with thoracolumbar kyphosis, who underwent 1-level lumbar PSO between March 2006 and June 2017, were retrospectively reviewed. Criteria for curve-matched thoracolumbar kyphosis were: (1) have same level of preoperative apex (pre-apex); (2) have similar global kyphosis (GK, the angle between the superior/inferior endplate of the maximally tilted upper and lower end vertebra) (the difference of GK less than 15˚). The radiographic parameters measured were sagittal vertical axis (SVA, the horizontal distance between the C7 plumb line and the posterosuperior corner of the S1), GK, thoracic kyphosis (TK, the angle between the T5 superior endplate and the T12 inferior endplate), lumbar lordosis (LL, the angle between the L1 and S1 superior endplate), sacral slope (SS, the angle between the sacral endplate and the horizontal line), pelvic tilt (PT, the angle between the vertical and the line joining the midpoint of the sacral plate and hip axis), and pelvic incidence (PI, the angle between the line vertical to the superior margin of S1 and the line connecting the sacral plate midpoint with the hip joint axis). All of these parameters and health-related quality of life (HRQoL, evaluated by preoperative and the last follow-up questionnaires including ODI and VAS) scores were collected before surgery and at the last follow-up. According to their osteotomy level, patients were devided into 2 sub-groups (L1 group and L2 group), and differences of these mentioned parameters between 2 groups were compared.Results: 26 curve-matched patients were recruited with a mean follow-up of 37.2 months. All patients improved significantly after surgery in HRQoL scores (VAS 1.6 vs 5.4, P< 0.001; ODI 11.9 vs 26.4, P< 0.001). Except for TK and PI, those radiographic parameters were also observed to be significantly changed after surgery. Compared to L2 group, PSO at L1 may have larger correction of TK (ΔTK -6.8 vs -0.3°, P= 0.164), PI (ΔPI -7.4 vs -0.7°, P= 0.364) and smaller correction of SVA (ΔSVA -105.3 vs -128.5 mm, P= 0.096), LL (ΔLL -31.1 vs -43.0°, P= 0.307) and SS (ΔSS 6.9 vs 12.2°, P= 0.279) but had no statistical significance.Conclusion: The results of this investigation showed that in AS-related thoracolumbar kyphosis patients with the same curve pattern, the different levels of osteotomy had little effect on the improvement of surgical outcomes. However, osteotomy at L2 is more likely to obtain a larger correction of SVA compared to osteotomy at L1.

This article summarizes the Next Generation Attenuation (NGA) Subduction (NGA-Sub) project, a major research program to develop a database and ground motion models (GMMs) for subduction regions. A comprehensive database of subduction earthquakes recorded worldwide was developed. The database includes a total of 214,020 individual records from 1,880 subduction events, which is by far the largest database of all the NGA programs. As part of the NGA-Sub program, four GMMs were developed. Three of them are global subduction GMMs with adjustment factors for up to seven worldwide regions: Alaska, Cascadia, Central America and Mexico, Japan, New Zealand, South America, and Taiwan. The fourth GMM is a new Japan-specific model. The GMMs provide median predictions, and the associated aleatory variability, of RotD50 horizontal components of peak ground acceleration, peak ground velocity, and 5%-damped pseudo-spectral acceleration (PSA) at oscillator periods ranging from 0.01 to 10 s. Three GMMs also quantified “within-model” epistemic uncertainty of the median prediction, which is important in regions with sparse ground motion data, such as Cascadia. In addition, a damping scaling model was developed to scale the predicted 5%-damped PSA of horizontal components to other damping ratios ranging from 0.5% to 30%. The NGA-Sub flatfile, which was used for the development of the NGA-Sub GMMs, and the NGA-Sub GMMs coded on various software platforms, have been posted for public use.

The influence of sulfate on ethanol oxidation reaction at a polyoriented Pt electrode has been investigated using cyclic voltammetry (CV) and combining chronoamperometry with high-performance liquid chromatography (HPLC) and in situ surface-enhanced Raman spectroscopy (SERS). In addition to the well-known inhibitory role, sulfate adsorption has also been found to increase the activity of Pt for ethanol oxidation under certain conditions, resulting from the strengthening adsorption of the substrate on Pt and inhibiting the formation of CO. Onset potential of ethanol oxidation moves to a lower value, and a new current peak at around 0.55 V (RHE) appears in the presence of sulfate in a potential range at which sulfate adsorption takes place. Also, the distributions of product concentration are consistent with CV, indicating that the sulfate adsorbed on Pt has a positive effect on ethanol electro-oxidation under certain conditions. Adsorption energy and geometric parameters calculated from density functional theory (DFT) further explain the positive role of sulfate adsorption in ethanol electrochemical oxidation.

Using a unique adhesive locomotion system, the rock-climbing fish (Beaufortia kweichowensis) adheres to submerged surfaces and crawls both forwards and backwards in torrential streams. To emulate this mechanism, we present a biomimetic robot inspired by the locomotion model of the rock-climbing fish. The prototype contains two anisotropic adhesive components with linkages connected to a linear actuator. Each anisotropic adhesive component consists of one commercial sucker and two retractable bioinspired fin components. The fin components mimic the abduction and adduction of pectoral and pelvic fins through the retractable part to move up and down. The robot prototype was tested on vertical and inverted surfaces, and worked successfully. These results demonstrate that this novel system represents a new locomotion solution for surface movement without detachment from the substrate.

BackgroundContinuous positive airways pressure (CPAP) and high-flow nasal oxygen (HFNO) are considered ‘aerosol-generating procedures’ in the treatment of COVID-19.ObjectiveTo measure air and surface environmental contamination with SARS-CoV-2 virus when CPAP and HFNO are used, compared with supplemental oxygen, to investigate the potential risks of viral transmission to healthcare workers and patients.Methods30 hospitalised patients with COVID-19 requiring supplemental oxygen, with a fraction of inspired oxygen ≥0.4 to maintain oxygen saturation ≥94%, were prospectively enrolled into an observational environmental sampling study. Participants received either supplemental oxygen, CPAP or HFNO (n=10 in each group). A nasopharyngeal swab, three air and three surface samples were collected from each participant and the clinical environment. Real-time quantitative polymerase chain reaction analyses were performed for viral and human RNA, and positive/suspected-positive samples were cultured for the presence of biologically viable virus.ResultsOverall 21/30 (70%) participants tested positive for SARS-CoV-2 RNA in the nasopharynx. In contrast, only 4/90 (4%) and 6/90 (7%) of all air and surface samples tested positive (positive for E and ORF1a) for viral RNA respectively, although there were an additional 10 suspected-positive samples in both air and surfaces samples (positive for E or ORF1a). CPAP/HFNO use or coughing was not associated with significantly more environmental contamination than supplemental oxygen use. Only one nasopharyngeal sample was culture positive.ConclusionsThe use of CPAP and HFNO to treat moderate/severe COVID-19 did not appear to be associated with substantially higher levels of air or surface viral contamination in the immediate care environment, compared with the use of supplemental oxygen.

By analyzing Newton’s rings, often encountered in interferometry, the parameters of spherical surfaces such as the rings’ center and the curvature radius can be estimated. First, the classical convolutional neural networks, visual geometry group (VGG) network and U-Net, are applied to parameter estimation of Newton’s rings. After these models are trained, the rings’ center and curvature radius can be obtained simultaneously. Compared with previous analysis methods of Newton’s rings, it is shown that the proposed method has higher precision, better immunity to noise, and lower time consumption. For a Newton’s rings pattern of ${{640}} \times {{480}}$ pixels comprising ${-}{{5}}\;{\rm{dB}}$ Gaussian noise or 60% salt-and-pepper noise, the parameters can be estimated by the VGG model in 0.01 s, the error of the rings’ center is less than one pixel, and the error of curvature radius is lower than 0.5%.

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ABSTRACTHeterotopic ossification (HO) is frequently seen in patients with spinal injuries. Therefore, this study aimed to characterize the association of HO with ankylosing spondylitis (AS) through gene expression profiling. The human transcriptomic datasets (GSE73754 and GSE94683) were obtained from the Gene Expression Omnibus database for analysis. Overlapping differentially expressed genes (DEGs) were identified between AS and HO disease states. Subsequently, weighted gene co-expression network analysis (WGCNA) was performed for constructing and identifying hub genes for each condition. Finally, a consensus of the overlapping DEGs and the hub genes in AS and HO was taken for determining the key genes involved in AS-induced HO. Quantitative real-time polymerase chain reaction and western blotting were used to detect the mRNA and protein expression levels in mesenchymal stem cells of AS patients and controls. Additionally, immunohistochemistry was performed on interspinous ligament samples for experimental validation of genes. DEG analysis identified 355 overlapping genes between HO and AS. WGCNA indicated that the salmon module of the 22 modules constructed, was most significantly correlated with AS-induced HO. Subsequently, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of the salmon module indicated the presence of genes enriched in proteasome regulatory particle and proteasome pathways. mRNA expression analysis identified TCP1 and PSMC1 as the key genes in AS-induced HO. Further validation of these genes could help elucidate their role in the complex association of AS and HO.

Pig farmers' willingness to recover production under the COVID-19 pandemic shock is significant to recover live pigs' supply in China in 2020. Increasing farmers' willingness to recover pig production contributes to enhance pig supply, stabilize the pig and pork market, and to improve pig farmers' income. This research studies the determinants of pig farmers' willingness to recover production under COVID-19 pandemic shock by applying survey data of 201 farmers in Huai'an City and Lin'an City and a logit regression model. The estimation results show that a farmer's risk perception, the duration time of a farmer's feed supply under COVID-19 pandemic shock, whether or not being a cooperative member, and a farmer's knowledge on government's policy designed to encourage pig production, a farmer's education level and production experience are the key determinants to a farmer's willingness to recover pig production. Thus, it's important for policymakers to solve the problems for farmers to get access to feed during the pandemic, to encourage the development of cooperatives, as well as to issue and advocate policies to encourage pig production. The study contributes to the scant literature by providing fresh empirical evidences on determinants of farmers' willingness to recover pig production. It has significance to farmers and governments to enhance farmers' willingness to recover production, which contributes to secure pig supply in China after the COVID-19 pandemic.

Surface modification offers a straightforward means to alter and enhance the properties and performance of materials, such as nanofiltration membranes for water softening. Herein, we demonstrate how a membrane’s surface charge can be altered by grafting different electrostatically varying copolymers onto commercial membrane surfaces using perfluorophenylazide (PFPA) photochemistry for enhanced ion separation performance. The native membrane’s performance—i.e., in terms of divalent cation separation—with copolymer coatings containing a positively charged quaternary ammonium (−N(Me)3+), a negatively charged sulfonate (−SO3–), and an essentially neutral zwitterion (sulfobetaine, −N(Me)2R2+, and −SO3–), respectively, indicates that: (a) the sulfonated polymer induces robust Coulombic exclusion of divalent anions as compared to the negatively charged native membrane surface on account of its higher negative charge; (b) the positively charged ammonium coating induces exclusion of cations more effectively than the native membrane; and significantly, (c) the zwitterion polymer coating, which reduces the surface roughness and improves wettability, in spite of its near-neutral charge enhances exclusion of both divalent cations and anions on account of aperture sieving by the compact zwitterion polymer that arises from its ability to limit the size of ions that transport through the polymer along with dielectric exclusion. The outcomes thereby inform new pathways to achieve size- and charge-based exclusion of ionic, molecular, and other species contained in liquid streams.

The mesoscopic evolution of the electrochemical dissolution of an Au(111) facet in acidic thiourea solutions was studied using in situ electrochemical atomic force microscopy (EC-AFM). At the open-circuit potential (OCP, 0.39 V vs RHE) of a gold bead electrode in 1.0 mM thiourea +0.1 M HClO4solution, the Au(111) plane displays pit-induced layer dissolution, which subsequently transforms into a wave-type dissolution at a rate of 0.05 μm/min. The dissolution of the Au(111) is suppressed in the acidic thiourea solutions as the potential on the negative side of the OCP is varied from 0.37 to 0.28 V (vs RHE) but is promoted as the potential on the positive side of the OCP is varied from 0.42 to 0.58 V (vs RHE). As the applied potential becomes more positive than 0.58 V (vs RHE), the dissolution rate of the Au(111) plane becomes too fast, exceeding the scanning capacity of the EC-AFM. The Au-deposition, starting from 0.25 V (vs RHE) to lower potentials, could be observed by situ-EC-AFM. The reason for the formation of a wave-type dissolution of the Au(111) plane was illustrated through the bonding energy between the sulfur atom of thiourea and gold atoms located at different positions in the Au(111) facet. The dependence of the dissolution of the Au(111) plane on the applied potential in acidic thiourea media is clarified in this work, which provides a new understanding of the kinetics and mechanism for the leaching of gold by thiourea at the mesoscopic level.

The thin-film composite (TFC) nanofiltration (NF) membrane is a very important method in solving the water crisis. However, the fabrication and industrialization of high-performance NF membranes still remains challenging. In this work, zwitterionic NF membranes via microwave-assisted grafting of betaine was first proposed. The resulting polyamide layer showed leaflike nanostructures after modification. Because of the enlarged permeation area and enhanced hydrophilicity derived from the unique leaflike structure, the optimal membrane permeability reached 40.8 L m–1h–1bar–1. This water permeance was 2.2 times as high as the original polypiperazine-amide membrane, with a Na2SO4rejection maintained at 97.0%. More importantly, the membrane demonstrated excellent selectivity to monovalent and divalent anions. This zwitterionic membrane fabricated by microwave-assisted grafting of betaine provides new insight for industrial scalable NF membranes with great potentials.

In a self-oscillating gel, unidirectional chemical waves generated by the Belousov–Zhabotinsky reaction can drive locomotion, which results from the difference between the push and pull forces in the wavefront and waveback, respectively. In a narrow tube, such a gel is subject not only to the asymmetric force engendered by the propagation of the chemical waves but also to additional forces originating from the capillary effect in the polymer skeleton. The ends of a self-oscillating gel in a tube are squeezed unequally during unidirectional motion, causing new waves of higher frequency and ultimately giving rise to reversal of the direction of chemical wave propagation. This peculiar phenomenon of a self-oscillating gel in a narrow glass tube results in a nonmonotonic evolution of the gel locomotion velocity.

Purpose: The purpose of this paper is to explore how consumers’ trust is enhanced by e-commerce-based agribusiness companies. It also aims to shed light on the role of social commerce in improving consumers’ trust. Design/methodology/approach: To achieve the research purpose, an in-depth multiple case study is performed. In this study, three cases in short food supply chain (SFSC) in China are selected, and they are all e-commerce agribusiness companies. They adopted common ways to build up, maintain and reinforce consumers’ trust. Findings: It is revealed that the companies innovatively adopted social commerce, both online and offline, to overcome the trust problems usually faced by e-commerce companies. It is also shown that offline contact with potential consumers is an important first step for agribusiness e-commerce entrepreneurs to build up trust with consumers. Research limitations/implications: By adopting a multiple case study method, the research has limited generalizability to other types of SFSCs. Since the findings are from Chinese agribusiness e-commerce companies, the generalization to other sectors must be done with caution. Practical implications: Some managerial implications are given as follows: first, offline contact with consumers could be realized through different channels. Taking advantage of existing social network or trying to find consumers in urban communities might be effective ways. Second, trust building with consumers is not an easy task, managers need to emphasize trust building, trust maintaining, as well as trust reinforcing with consumers. In agri-food sector, managers might need to specifically address the importance of food safety and quality so as to not lose consumer trust in one night. Originality/value: The study has mainly two contributions: first, it has managerial implications for agribusiness e-commerce entrepreneurs, addressing the important role of social presence in building up consumer trust. Second, it contributes to social presence and social relations literature by providing new empirical evidence from e-commerce in agri-food sector and in developing countries.

Purpose: This editorial article introduces and analyzes a variety of new organizational forms that rapidly emerged in Africa, Asia, Latin America and Eastern Europe in the latest two decades. Among the others, these include: business model partnerships, business platforms, incubators and hubs, public–private partnerships, agribusiness companies' foundations and spin-offs, short supply chains, community-supported agriculture and other community self-organizing experiences. Building upon the recent literature and the five selected papers in this special issue, the authors discuss what is novel in these organizations and why, when and how they emerge and evolve over time. Design/methodology/approach: The authors identify three elements that, when considered together, explain and predict the emergence and evolution of these new organizational forms: institutions, strategies and learning processes. Findings: The authors demonstrate that societal actors seeking to (re)design these new organizational forms need to consider these three elements to combine the pursuit of their interests of their own constituencies with the sustainable development goals (SDGs). Originality/value: Taking stock from the literature, the authors invite future research on new organizational forms to take explicitly the pursuit of the SDGs into consideration; to build upon a process ontology; and to deeply reflect on our positionality of scientists studying and sometimes engaging in these organizations.

The trithionate–iodate reaction has been studied spectrophotometrically in an acidic medium at 25.0 ± 0.1 °C in phosphoric acid/dihydrogen phosphate buffer, monitoring the absorbance at 468 nm at the isosbestic point of the iodine–triiodide ion system and at I= 0.5 M ionic strength adjusted by sodium perchlorate. The main characteristics of the title system are very reminiscent of those found recently in the pentathionate–iodate and the pentathionate–periodate reactions, the systems paving the way for classifying clock reactions. Thorough analysis revealed that the direct trithionate–iodate reaction plays a subtle role only to produce a trace amount of iodide ion via a finite sequence of reactions, and once its concentration reaches a certain level, then the reaction is almost exclusively governed by the trithionate–iodine and iodide–iodate reactions. The title reaction, as expected, was experimentally proven to be autocatalytic with respect to iodide ion. A simple three-step Landolt-type kinetic model is proposed to describe adequately the most important kinetic features of the title system that can easily be extended to a feasible sequence of elementary and quasi-elementary reactions.

Monotherapy, especially the use of antibodies targeting vascular endothelial growth factor (VEGF), has shown limitations in treating choroidal neovascularization (CNV) since reactive oxygen species (ROS) also exacerbate CNV formation. Herein, we developed a combination therapy based on a DNA origami platform targeting multiple components of ocular neovascularization. Our study demonstrated that ocular neovascularization was markedly suppressed by intravitreal injection of a rectangular DNA origami sheet modified with VEGF aptamers (Ap) conjugated to an anti-VEGF antibody (aV) via matrix metalloproteinase (MMP)-cleavable peptide linkers in a mouse model of CNV. Typically, the DNA origami-based therapeutic platform selectively accumulates in neovascularization lesions owing to the dual-targeting ability of the aV and Ap, followed by the cleavage of the peptide linker by MMPs to release the antibody. Together, the released antibody and Ap inhibited VEGF activity. Moreover, the residual bare DNA origami could effectively scavenge ROS, reducing oxidative stress at CNV sites and thus maximizing the synergistic effects of inhibiting neovascularization.

ObjectiveTo evaluate whether a structured online supervised group physical and mental health rehabilitation programme can improve health related quality of life compared with usual care in adults with post-covid-19 condition (long covid).DesignPragmatic, multicentre, parallel group, superiority randomised controlled trial.SettingEngland and Wales, with home based interventions delivered remotely online from a single trial hub.Participants585 adults (26-86 years) discharged from NHS hospitals at least three months previously after covid-19 and with ongoing physical and/or mental health sequelae (post-covid-19 condition), randomised (1:1.03) to receive the Rehabilitation Exercise and psycholoGical support After covid-19 InfectioN (REGAIN) intervention (n=298) or usual care (n=287).InterventionsBest practice usual care was a single online session of advice and support with a trained practitioner. The REGAIN intervention was delivered online over eight weeks and consisted of weekly home based, live, supervised, group exercise and psychological support sessions.Main outcome measuresThe primary outcome was health related quality of life using the patient reported outcomes measurement information system (PROMIS) preference (PROPr) score at three months. Secondary outcomes, measured at three, six, and 12 months, included PROMIS subscores (depression, fatigue, sleep disturbance, pain interference, physical function, social roles/activities, and cognitive function), severity of post-traumatic stress disorder, general health, and adverse events.ResultsBetween January 2021 and July 2022, 39 697 people were invited to take part in the study and 725 were contacted and eligible. 585 participants were randomised. Mean age was 56 (standard deviation (SD) 12) years, 52% were female participants, mean health related quality of life PROMIS-PROPr score was 0.20 (SD 0.17), and mean time from hospital discharge was 323 (SD 144) days. Compared with usual care, the REGAIN intervention led to improvements in health related quality of life (adjusted mean difference in PROPr score 0.03 (95% confidence interval 0.01 to 0.05), P=0.02) at three months, driven predominantly by greater improvements in the PROMIS subscores for depression (1.39 (0.06 to 2.71), P=0.04), fatigue (2.50 (1.19 to 3.81), P<0.001), and pain interference (1.80 (0.50 to 3.11), P=0.01). Effects were sustained at 12 months (0.03 (0.01 to 0.06), P=0.02). Of 21 serious adverse events, only one was possibly related to the REGAIN intervention. In the intervention group, 141 (47%) participants fully adhered to the programme, 117 (39%) partially adhered, and 40 (13%) did not receive the intervention.ConclusionsIn adults with post-covid-19 condition, an online, home based, supervised, group physical and mental health rehabilitation programme was clinically effective at improving health related quality of life at three and 12 months compared with usual care.Trial registrationISRCTN registry ISRCTN11466448.

Herein, we report a DNA origami plasmonic nanoantenna for the programmable surface-enhanced Raman scattering (SERS) detection of cytokine release syndrome (CRS)-associated cytokines (e.g., tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)) in cancer immunotherapy. Typically, the nanoantenna was made of self-assembled DNA origami nanotubes (diameter: ∼19 nm; length: ∼90 nm) attached to a silver nanoparticle-modified silicon wafer (AgNP/Si). Each DNA origami nanotube contains one miniature gold nanorod (AuNR) inside (e.g., length: ∼35 nm; width: ∼7 nm). Intriguingly, TNF-α and IFN-γ logically regulate the opening of the nanotubes and the dissociation of the AuNRs from the origami structure upon binding to their corresponding aptamers. On this basis, we constructed a complete set of Boolean logic gates that read cytokine molecules as inputs and return changes in Raman signals as outputs. Significantly, we demonstrated that the presented system enables the quantification of TNF-α and IFN-γ in the serum of tumor-bearing mice receiving different types of immunotherapies (e.g., PD1/PD-L1 complex inhibitors and STING agonists). The sensing results are consistent with those of the ELISA. This strategy fills a gap in the use of DNA origami for the detection of multiple cytokines in real systems.

Emerging evidence indicate that miRNAs play an important role on gastric cancer (GC) progression via regulating several downstream targets, but it is still partially uncovered. This study aimed to explore the molecular mechanisms of GC by comprehensive analysis of mRNAs and miRNA expression profiles. The mRNA and miRNA expression profiles of GSE79973 and GSE67354 downloaded from Gene Expression Omnibus were used to analyze the differentially expressed genes (DEGs) and DE-miRNAs among GC tissues and normal tissues. Then, targets genes of DE-miRNAs were predicted and the DE-miRNA–DEG regulatory network was constructed. Next, function enrichment analysis of the overlapped genes between the predicted DE-miRNAs targets and DEGs was performed and a protein–protein interactions network of overlapped genes was constructed. Finally, RT-PCR analysis was performed to detect the expression levels of several key DEGs and DE-miRNAs. A set of 703 upregulated and 600 downregulated DEGs, as well as 8 upregulated DE-miRNAs and 27 downregulated DE-miRNAs were identified in GC tissue. hsa-miR-193b-3p and hsa-miR-148a-3p, which targeted most DEGs, were highlighted in the DE-miRNA–DEG regulatory network, as well as hsa-miR-1179, which targeted KNL1, was newly predicted to be associated with GC. In addition, NCAPG, which is targeted by miR-193b-3p, and KNL1, which is targeted by hsa-miR-1179, had higher degrees in the PPI network. RT-qPCR results showed that hsa-miR-148a-3p, hsa-miR-193b-3p, and hsa-miR-1179 were downregulated, and NCAPGand KNL1were upregulated in GC tissues; this is consistent with our bioinformatics-predicted results. The downregulation of miR-193b-3p might contribute to GC cell proliferation by mediating the upregulation of NCAPG; as additionally, the downregulation of miR-193b-3p might contribute to the mitotic nuclear division of GC cells by mediating the upregulation of KNL1.

WE43 Magnesium alloy is of great potential in the aerospace, biomedicine and transportation fields, which can be promisingly promoted by the laser powder bed fusion (LPBF) technology. This study aims to systematically investigate the microstructure and mechanical properties of the WE43 alloy fabricated by LPBF and deep cryogenic treatment (DCT) in comparison with traditionally cast and wrought alloys. The results show that the LPBF leads to the precipitation of the strengthening particles of the β''-Mg3(Y, Nd), β'-Mg12NdY phase and β1-Mg3Nd, which are significantly different from the conventional counterparts. The DCT triggers lattice shrinkage and the formation of micro stresses to store strain energy, thus reducing the precipitation driving force and promoting the precipitation in the LPBF-DCTed alloy. Moreover, the DCT process generates large compressive stresses that induce crystal defects such as dislocations, leading to subsequent strengthening. The alloy fabricated by LPBF-DCT shows a 17% increase in yield strength, a 30 MPa increase in ultimate tensile strength and a 40% increase in elongation, which is much higher than the conventional counterparts. These findings highlight the great potential of coupling LPBF technology with the DCT process for fabricating high-performance magnesium rare-earth alloys.