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By enhancing light-matter interaction, terahertz (THz) metasurface can significantly improve the performance of THz spectroscopic sensing. Despite their theoretical promise, a robust and practical characterization method for THz metasurface remains urgently needed. This article presents a novel characterization approach for THz metasurface that is resilient to environmental water vapor, enabling ultrahigh frequency selectivity and polarization sensitivity. The performance of the proposed method is demonstrated using a series of lithography-fabricated split-ring metasurface, theoretically designed to be evenly separated over the 0.6–1.0 THz range. A continuous wave THz frequency-domain spectroscopy system was employed for experimental characterization. Following sophisticated raw photocurrent data processing, ultrahigh frequency resolution (0.05 GHz) spectral characterization was achieved within the frequency range of 0.05 to 1.4 THz. The measured data exhibit linear correlation with the theoretical simulation results, and deviations of the resonance frequencies are less than 0.02 THz. By presenting the characterization results with and without water vapor exhibited in the THz pathway, we demonstrate the robustness of the proposed method in the ambient environment. Furthermore, we incorporated a sample rotating frame into the THz optical path to achieve polarization-sensitive measurements. As the era of 6G integrated sensing and communication approaches, our research significantly advances the practicality of metasurface enhanced THz sensing.

Respiratory signals are critical clinical diagnostic criteria for respiratory diseases and health conditions, and respiratory sensors play a crucial role in achieving the desired respiratory monitoring effect. High sensitivity to a single factor can improve the reliability of respiratory monitoring, and maintaining the hygiene of the sensors is also important for daily health monitoring. Herein, we propose a flexible Au-modified anatase titanium dioxide resistive respiratory sensor, which can be mechanically compliantly attached to curved surfaces for respiratory monitoring in different modalities (i.e., respiratory intensity, frequency, and rate). The uniform and preferentially oriented anatase titanium dioxide films gained by the polymer-assisted deposition technique can be fabricated on flexible substrates through a liquid-assisted transferring process. The Au modification can enhance surface plasmon resonance to facilitate the photocatalytic activity of titanium dioxide, and the optimized distribution of Au on the surface of titanium dioxide film made the sensor have an excellent antibacterial effect. The uniquely designed encapsulation can effectively control the contact between the surface of titanium dioxide films and electrodes, allowing the flexible sensor to exhibit fast response time (0.71 s) and recovery time (1.06 s) to respiratory as well as insensitivity or low sensitivity to other factors (i.e., gas composition, humidity, temperature, stress, and strain). This work provided an effective strategy for flexible wearable respiratory sensors and has great potential in daily respiratory monitoring for health management and pandemic control.

Autonomous Intersection Management (AIM) systems present a new paradigm for conflict-free cooperation of connected autonomous vehicles (CAVs) at road intersections, the aim of which is to eliminate collisions and improve the traffic efficiency and ride comfort. Given the challenges of current centralized coordination methods in balancing high computational efficiency and robust safety assurance, this paper proposes an innovative conflict-free management scheme for CAVs at unsignalized intersections, leveraging safe multi-agent deep reinforcement learning (MADRL). Firstly, we formulate the safe MADRL problem as a constrained Markov game (CMG) and then transform the AIM problem into a CMG by carefully designing state, action, reward, and cost functions. Subsequently, we propose the Multi-Agent Constrained Policy Optimization (MACPO), specifically tailored to solve the CMG problem. MACPO incorporates safety constraints that further restrict the trust region formed by the Kullback-Leibler (KL) divergence, facilitating reinforcement learning policy updates that maximize performance while keeping constraint costs within their limit bounds. This leads us to introduce the MACPO-based AIM Algorithm. Finally, we train an AIM policy and compare its computation time, ride comfort, traffic efficiency, and safety with management schemes based on Model Predictive Control (MPC), Mixed Integer Programming (MIP), and non-safety-aware reinforcement learning. According to the results, compared with the MPC and MIP methods, our method has increased computational efficiency by 65.22 times and 731.52 times respectively, and has improved traffic efficiency by 2.41 times and 1.80 times respectively. In contrast to the non-safety awareness RL methods, our method achieves a zero collision rate for the first time, while also enhancing ride comfort, highlighting the advantages of using MACPO.

The magnetoenterogram (MENG) utilizes the superconducting quantum interference device (SQUID) with ultrahigh sensitivity to detect magnetic signals emanating from the intestines. The magnetic field distribution reflects the ischemic condition of the mesentery to diagnose acute mesenteric ischemia. In practice, the intestinal magnetic signal is very weak and difficult to identify from noises, that is, the signal-to-noise ratio (SNR) is relatively low. An innovative magnetic flux concentrator (MFC) combined with the MENG is presented in the article to enhance the SNR. The specific work includes the selection of MFC material with suitable permeability and optimization of the diameters and heights. The enhancements for various directional magnetic signals were simulated. Finally, some preliminary experiments were conducted to test the MFC enhancements. The intestinal signal was simulated using a powered coil at low frequencies. Approximately a tenfold enhancement is achieved, remaining constant during the 0.2–1-Hz range.

Monitoring blood glucose concentration is crucial in diagnosing and predicting clinical diabetes progression. However, the invasion of blood sampled by venipuncture and the informative delay of alternative biofluids inevitably affect dynamic and accurate monitoring. Here, we proposed a skin-patchable, noninvasive, and wireless blood glucose biosensing system composed of a flexible electromagnetic resonant circuit and a wireless data acquisition unit, correlating the S parameter shifts and glucose level-inducing blood dielectric property alteration. Ex vivo and volunteer hypo- to hyperglycemic monitoring validations achieved supered fidelity and correlation with high sensitivity > 0.0626°/(mg/dl). The correlation coefficient values were 0.996 and 0.945 for ex vivo mammalian skin and healthy volunteers’ oral glucose tolerance tests, comparable to commercial blood glucose meters. Emerging noninvasive and wireless modalities would strive to bridge gaps between minimal discomfort and reliable measurements, spurring the widespread adoption of this portable blood glucose monitoring system.

Graphical Abstract: This work proposes a bioactive fiber-based sensor patch comprising a non-enzyme Co3O4/carbon fiber-based biorecognition element and a temperature calibration unit. The sole fiber-based sensor could selectively monitor dopamine and lactic acid contents based on cyclic voltammetry and amperometry, exhibiting a wide detection range, excellent selectivity and reproducibility with temperature calibration in an ambient temperature range from 25 to 45 ℃, promising personalized and preventative health care in various scenarios

Microsphere-assisted super-resolution imaging technology offers label-free, real-time dynamic imaging via white light, which has potential applications in living systems and the nanoscale detection of semiconductor chips. Scanning can aid in overcoming the limitations of the imaging area of a single microsphere superlens. However, the current scanning imaging method based on the microsphere superlens cannot achieve super-resolution optical imaging of complex curved surfaces. Unfortunately, most natural surfaces are composed of complex curved surfaces at the microscale. In this study, we developed a method to overcome this limitation through a microsphere superlens with a feedback capability. By maintaining a constant force between the microspheres and the sample, noninvasive super-resolution optical imaging of complex abiotic and biological surfaces was achieved, and the three-dimensional information on the sample was simultaneously obtained. The proposed method significantly expands the universality of scanning microsphere superlenses for samples and promotes their widespread use.

Odorants are detected as smell in the nasal epithelium of mammals by two G-protein-coupled receptor families, the odorant receptors and the trace amine-associated receptors1,2(TAARs). TAARs emerged following the divergence of jawed and jawless fish, and comprise a large monophyletic family of receptors that recognize volatile amine odorants to elicit both intraspecific and interspecific innate behaviours such as attraction and aversion3–5. Here we report cryo-electron microscopy structures of mouse TAAR9 (mTAAR9) and mTAAR9–Gsor mTAAR9–Golftrimers in complex with β-phenylethylamine, N,N-dimethylcyclohexylamine or spermidine. The mTAAR9 structures contain a deep and tight ligand-binding pocket decorated with a conserved D3.32W6.48Y7.43motif, which is essential for amine odorant recognition. In the mTAAR9 structure, a unique disulfide bond connecting the N terminus to ECL2 is required for agonist-induced receptor activation. We identify key structural motifs of TAAR family members for detecting monoamines and polyamines and the shared sequence of different TAAR members that are responsible for recognition of the same odour chemical. We elucidate the molecular basis of mTAAR9 coupling to Gsand Golfby structural characterization and mutational analysis. Collectively, our results provide a structural basis for odorant detection, receptor activation and Golfcoupling of an amine olfactory receptor.

Background Opioid addiction is a chronic brain disorder characterized by a series of withdrawal symptoms in behavioral, psychological, and neurobiological manifestations. Withdrawal symptoms are the main cause of relapse after periods of abstinence; thus, the treatment is focused on abstinence symptoms. Due to most of all types of opioid agonist drugs carry a potential for addiction and exacerbation of withdrawal symptoms, nondrug methods have great potentials in clinical applications. Electro-acupuncture (EA), as a novel nonpharmacological approach, combined with methadone has a long-term positive efficacy on treating addiction. Therefore, we designed a protocol to evaluate the adjuvant effect of EA for treating withdrawal symptoms of opioid addiction.Method To review reports of relevant clinical trials, we will search English language databases (EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials) and Chinese databases (Chinese Biomedical Literatures, China National Knowledge Infrastructure, Wanfang, and VIP). We will collect documents from the earliest possible date up to May 2020. We will also search online trial registries such as ClinicalTrials. gov (ClinicalTrials.gov/), the European Medicine Agency (www.ema.europa.eu/ema/), and WHO International Clinical Trials Registry Platform (www.who.int/ictrp). We will select randomized controlled trials (RCT) for withdrawal from opioid addiction involving EA-methadone and methadone alone treatment. We will use psychological assessment scales to evaluate treatment major outcomes which include numerous components such as OWS, VAS, HAMD, HAMA; then urinalysis and methadone dosage also will be measure as the additional outcomes. Finally, RevMan5 software will be used for literature quality evaluation and data analysis.Result: To evaluate the efficacy of EA in combination therapy by observing the outcomes of corresponding scale, urinalysis and decreasing methadone.Conclusion: This protocol will be used to evaluate the efficacy and safety of EA in combination with methadone in treatment of opioid addiction withdrawal symptoms.Abbreviations: Opioid dependence, OWS=Opiate Withdrawal Scale, VAS=Craving Visual Analog Scale, PWSS=Post-withdrawal symptoms Scale, HAMD=Hamilton Depression Scale, HAMA=Hamilton Anxiety Scale, RCTs=Randomized Controlled Trials, EA=Electrical Acupuncture, PRISMA=Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Nanomanipulation provides high operating accuracy and has been successfully applied in many fields such as nanoparticle assembly, nanowire alignment, and semiconductor device manufacturing. However, because of the limits of optical diffraction, the use of nanomanipulation is challenged by a lack of visual feedback at the nanoscale, and thus, its efficiency is difficult to be improved. In this study, we developed a novel method of microlens-enhanced nanomanipulation capable of real-time super-resolution imaging. Nanomanipulation was performed using the atomic force microscopy (AFM) mechanism by coupling a microlens to an AFM probe, and optical imaging with a minimum characteristic size of 80 nm is realized by combining the microlens with the optical imaging system. Under the conditions of fluorescent illumination and white light illumination, nanomanipulations were achieved under real-time visual guidance for fluorescent nanoparticles with a diameter of 100 nm and silver nanowires with a diameter of 80 nm, respectively. This method enables the possibility of in situ observation and manipulation, which can potentially be used for biological samples.

Flexible bioelectronics, including wearable and implantable electronics, have revolutionized the way of human-machine interaction due to the fact that they can provide natural and seamless interactions with humans and keep stable and durable at strained states. As sensor elements or biomimetic actuators, flexible bioelectronics can dynamically sense and monitor physiological signals, reveal real-time physical health information and provide timely precise stimulations or treatments. Thus, the flexible bioelectronics are playing increasingly important roles in human-health monitoring and disease treatment, which will significantly change the future of healthcare as well as our relationships with electronics. This review summarizes recent major progress in the development of flexible substrates or encapsulation materials, sensors, circuits and energy-autonomous powers toward digital healthcare monitoring, emphasizing its role in biomedical applications in vivo and problems in practical applications. A future perspective into the challenges and opportunities in emerging flexible bioelectronics designs for the next-generation healthcare monitoring systems is also presented.

In this paper, we present the application of transmissive terahertz (THz) time-domain spectroscopy for determining molecular polarizability for three widely applied solvents: water, ethanol, and acetone. Molecular polarizabilities of those solvents are obtained from the refractive index by using the Lorentz–Lorenz equation. The measured THz molecular polarizabilities are comparable with theoretical values estimated with both the first principle calculation and the atomic polarizability additive model. The THz spectra are presented over frequencies ranging from 0.3 to 1.2 THz (10−40cm^−1). The molecular polarizability at 1.0 THz is determined as 3.81±0.03, 7.04±0.07, and 7.9±0.2?^3 for water, ethanol, and acetone, respectively.

The thermal runaway (TR) of lithium-ion batteries (LIBs) is hindering the large-scale promotion of new energy vehicles. The process of TR is often accompanied by high-temperature air flow and the eruption of particles. The particle emission was supposed to pose a risk of igniting combustibles in the surrounding environment. Relevant studies have been conducted, but reviews of these studies are lacked. Therefore, we summarize the properties of particles released upon the TR of LIBs, including morphology, mass, size, thermal stability, chemical composition, spread and deposition, temperature, and eruption distance. It was found that most of the particles appear as black, irregular-shaped powders, and their main components are carbon, carbonates, metals, metal oxides and various organic matter. Particle contains >30 elements, of which up to 40 % are metals, and >70 % of metals are polluting to the atmosphere, soil or water. Owing to different particle sizes, particles may eventually be deposited or suspended in the air, harming the environment and human body. Therefore, it is necessary to strengthen the research, supervision and treatment of LIB particle emissions. Specifically, conduct an in-depth study of the temperature and eruption range of sparks, and focus on the analysis of non-metallic elements, and conduct a comprehensive composition analysis and determination, and study the influencing factors of particle size distribution and guide the design of protective masks. Our work may pave the way for providing theoretical guidance for improving the safety of LIBs and establishing effective particle emission management methods.

In this paper, we present the application of THz frequency-domain spectroscopy (THz-FDS) for determining the refractive index in an ambient environment. The signal phase is extracted from the periodically oscillated photocurrent by a magnitude normalization method. The proposed method is demonstrated using experimental data of polytetrafluoroethylene and α-lactose monohydrate as reference materials collected at a relative humidity of around 17.0% ± 2.0%. A detailed comparison to the existing algorithms, including the Hilbert transform and extreme points analysis, reveals the remarkable reliability of our proposed method. This study expands the characterization capabilities of THz-FDS and furthers the development of practical terahertz spectroscopy applications.

Being one of the core power units of electric vehicles, the lithium-ion batteries (LIBs) are broadly concerned. However, in the cases of abuses, LIBs may counter thermal runaway, threatening the personal and property safety of users. In order to avoid the occurrence of thermal runaway, the battery thermal management system (BTMS) has been introduced to improve the safety, optimize the efficiency and prolong the service life of lithium-ion batteries. In this review, feasible thermal management schemes of LIBs system were summarized chronically, different thermal management schemes were evaluated, and case studies were made. The schemes of controlling the internal reaction control in the battery are highlighted as well. This review offers a comprehensive view of BTMS and proposes a promising future for the employment of lithium-ion batteries.

Malocclusion is a prevalent dental health problem plaguing over 56% worldwide. Mechanical orthodontic aligners render directional teeth movement extensively used for malocclusion treatment in the clinic, while mechanical regulation inefficiency prolongs the treatment course and induces adverse complications. As a noninvasive physiotherapy, an appropriate electric field plays a vital role in tissue metabolism engineering. Here, we propose an occlusion-activated electromechanical synergistic dental aligner that converts occlusal energy into a piezo-excited alternating electric field for accelerating orthodontic tooth movement. Within an 18-day intervention, significantly facilitated orthodontic results were obtained from young and aged Sprague–Dawley rats, increasing by 34% and 164% in orthodontic efficiency, respectively. The different efficiencies were attributed to age-distributed periodontal tissue status. Mechanistically, the electromechanical synergistic intervention modulated the microenvironment, enhanced osteoblast and osteoclast activity, promoted alveolar bone metabolism, and ultimately accelerated tooth movement. This work holds excellent potential for personalized and effective treatment for malocclusions, which would vastly reduce the suffering of the long orthodontic course.

As the energy density of lithium-ion batteries continues to increase, battery safety issues characterized by thermal runaway have become increasingly severe. Battery safety issues have severely restricted the large-scale application of power batteries. Among them, the flammable liquid organic electrolyte is one of the main reasons for the safety hazards of battery thermal runaway. This article reviews the flame-retardant mechanism and research progress of phosphorus-based flame-retardant additives, nitrogen-based flame-retardant additives, and halogen-based flame-retardant additives. The design strategies of conventional flame-retardant additives and intelligent flame-retardant additives in lithium-ion batteries are summarized. Finally, a development direction and research prospects of flame-retardant additives in lithium-ion battery electrolytes are prospected.

This paper aims to solve the problem of optimal design on a comfortable human-machine arrangement of car drivers with different physical signs under dynamic manipulation. Based on the biomechanical characteristic of human skeletal muscle and Hill muscle mechanics model, this paper constructs the human seat musculoskeletal model of 5th, 50th, and 95th percentile physical signs of Chinese car drivers under dynamic manipulation. The six-degree-of-freedom flexible test bench was set up and the center composite method was used to optimize the number of experiments. The consistency and relevance analysis of the actual measurement and dynamic manipulation simulation was carried out to comprehensively analyze the human-machine arrangement parameters such as vehicle seat, pedal, and steering wheel, so as to realize the optimization design of the hard point size of comfortable driving posture and verify the rationality and applicability of the test results through the vehicle road test.

Research on neighbourhood environments and depression has concentrated on public health in developed countries. This study aims to enrich the discourse on geographic characteristics and depression by providing new evidence of direct and indirect associations between suburban neighbourhood environments and depression in urban China.