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Abstract The construction of near‐infrared (NIR) light‐activated hydrogen‐producing materials that enable the controlled generation and high‐concentration release of hydrogen molecules in deep tumor tissues and enhance the effects of hydrogen therapy holds significant scientific importance. To address the key technical challenge of low‐efficiency oxidation–reduction reactions for narrow‐bandgap photocatalytic materials, this work proposes an innovative approach for the controllable fabrication of multiphoton photocatalytic materials to overcome the limitations imposed by traditional near‐infrared photocatalysts with “narrow‐bandgap” constraints. Herein, an NIR‐responsive multiphoton photocatalyst, ZrTc‐Co, is developed by utilizing a post‐synthetic coordination modification strategy to introduce hydrogenation active site CoII into a multiphoton responsive MOF (ZrTc). The results reveal that with the introduction of the CoII site, electron–hole recombination can be efficiently suppressed, thus promoting the efficiency of hydrogen evolution reaction. In addition, the integration of CoII can effectively enhance charge transfer and improve static hyperpolarizability, which endows ZrTc‐Co with excellent multiphoton absorption. Moreover, hyaluronic acid modification endows ZrTc‐Co with cancer cell‐specific targeting characteristics, laying the foundation for tumor‐specific elimination. Collectively, the proposed findings present a strategy for constructing NIR‐II light‐mediated hydrogen therapeutic agents for deep tumor elimination.

Objective Contactless power supply method, leveraging the advantages of no direct electrical contact between the primary and secondary side coils, is currently being explored in the rail transit industry. The high-power, high-frequency application scenarios pose challenges in the design of the contactless traction power supply system, component selection, and coupling mechanism design. It requires optimization of the design scheme and system efficiency. Method For rail transit application scenarios, the system structure of a contactless traction power supply system based on the LCC-S (inductance-capacitor-capacitor-series) compensation topology is introduced. A 250 kW contactless power supply system is designed, utilizing double D-shaped coils for the primary track coils and secondary receiving coils. The impact of factors such as mutual inductance of coupling coils and losses in magnetic materials on system efficiency is studied. System circuit model and coupling coil model are established. The system is simulated based on the model, and parameters for the magnetic core thickness in different regions of the secondary coils are optimized. An experimental platform for contactless traction power supply system is built, and tests are conducted at a power level of 250 kW to validate the effectiveness of the design optimization method. Result & Conclusion The simulation and experimental results confirm the effectiveness and feasibility of the design optimization method. Optimization of the core layout ensures coil mutual inductance and reduces core losses. The system demonstrates the capability of delivering a rated output power of 250 kW. Under air gap heights of 70 mm and 80 mm, the static and dynamic operating efficiencies of the system are both greater than 90%.

Abstract Understanding the intricate nanoscale architecture of neuronal myelin during central nervous system development is of utmost importance. However, current visualization methods heavily rely on electron microscopy or indirect fluorescent method, lacking direct and real-time imaging capabilities. Here, we introduce a breakthrough near-infrared emissive curcumin-BODIPY derivative (MyL-1) that enables direct visualization of myelin structure in brain tissues. The remarkable compatibility of MyL-1 with stimulated emission depletion nanoscopy allows for unprecedented super-resolution imaging of myelin ultrastructure. Through this innovative approach, we comprehensively characterize the nanoscale myelinogenesis in three dimensions over the course of brain development, spanning from infancy to adulthood in mouse models. Moreover, we investigate the correlation between myelin substances and Myelin Basic Protein (MBP), shedding light on the essential role of MBP in facilitating myelinogenesis during vertebral development. This novel material, MyL-1, opens up new avenues for studying and understanding the intricate process of myelinogenesis in a direct and non-invasive manner, paving the way for further advancements in the field of nanoscale neuroimaging. Graphical Abstract

Fuel cell vehicles are considered as the direct alternative to fuel vehicles due to their similar driving range and refueling time. The United Nations World Forum for Harmonization of Vehicle Regulations (UN/WP29) released the Global Technical Regulation on Hydrogen and Fuel Cell Vehicles (GTR13) in July 2013, which was the first international regulation in the field of fuel cell vehicles. There exist some differences between GTR13 and the existing safety technical specifications and standards in China. This paper studied the safety requirements of the GTR13 compressed hydrogen storage system, analyzed the current hydrogen storage safety standards for fuel cell vehicles in China, and integrated the advantages of GTR13 to propose relevant suggestions for future revision of hydrogen storage standards for fuel cell vehicle in China.

Introduction: Closed-loop control of deep brain stimulation (DBS) is beneficial for effective and automatic treatment of various neurological disorders like Parkinson’s disease (PD) and essential tremor (ET). Manual (open-loop) DBS programming solely based on clinical observations relies on neurologists’ expertise and patients’ experience. Continuous stimulation in open-loop DBS may decrease battery life and cause side effects. On the contrary, a closed-loop DBS system uses a feedback biomarker/signal to track worsening (or improving) of patients’ symptoms and offers several advantages compared to the open-loop DBS system. Existing closed-loop DBS control systems do not incorporate physiological mechanisms underlying DBS or symptoms, e.g., how DBS modulates dynamics of synaptic plasticity.Methods: In this work, we propose a computational framework for development of a model-based DBS controller where a neural model can describe the relationship between DBS and neural activity and a polynomial-based approximation can estimate the relationship between neural and behavioral activities. A controller is used in our model in a quasi-real-time manner to find DBS patterns that significantly reduce the worsening of symptoms. By using the proposed computational framework, these DBS patterns can be tested clinically by predicting the effect of DBS before delivering it to the patient. We applied this framework to the problem of finding optimal DBS frequencies for essential tremor given electromyography (EMG) recordings solely. Building on our recent network model of ventral intermediate nuclei (Vim), the main surgical target of the tremor, in response to DBS, we developed neural model simulation in which physiological mechanisms underlying Vim–DBS are linked to symptomatic changes in EMG signals. By using a proportional–integral–derivative (PID) controller, we showed that a closed-loop system can track EMG signals and adjust the stimulation frequency of Vim–DBS so that the power of EMG reaches a desired control target.Results and discussion: We demonstrated that the model-based DBS frequency aligns well with that used in clinical studies. Our model-based closed-loop system is adaptable to different control targets and can potentially be used for different diseases and personalized systems.

In this paper, the split Hopkinson pressure bar (SHPB) test was used to investigate the variation of dynamic compressive properties of SHCC with various freeze-thaw (FT) cycles and strain rates. The full-field strain distribution and cracking characteristics of FT-damaged SHCC after the SHPB test were quantitatively and characterized by the high-speed digital image correlation (DIC) technique. The internal damage was analyzed using an X-ray CT imaging technique and SEM (Scanning electron microscope). Results show that dynamic compressive strength, energy absorption ability and dynamic increase factor (DIF) increase as the increase of strain rate, and these increase trends are weakened by the FT damage. The DIF model is established considering the number of FT cycles and strain rates. Variation of crack width in SHCC obtained through the high-speed DIC technique can be divided into three stages: linear increase stage, plateau stage and slow increase stage.

Understanding the ice formation process in cement-based materials is necessary to evaluate the freeze-thaw durability of concrete structures serviced in cold regions. However, the influencing mechanism of deicing salt on the ice formation process in cement-based material remains unclear. In this paper, the influence of NaCl on the ice formation process in the mortar was investigated by tracking the state and movement of pore water during the ice formation process using the low-field nuclear magnetic resonance (LF-NMR) technique. The obtained results show that during the ice formation process, the movement of pore water after being saturated with NaCl solution from the gel pore to the capillary pore is more distinct, regardless of ordinary and air-entrained mortar. Moreover, the increase of the signal amplitude of LF-NMR illustrates that NaCl solution promotes the conversion of chemically bound water to physically absorbed water. This effect leads to an increase in the free water content, and the saturation of the capillary pores is vulnerable to reaching critical saturation.

Dynamic mechanical behavior of strain-hardening cementitious composites (SHCC) incorporated with different fly ash content at various curing ages was investigated using drop weight impact test. Direct tensile, compressive and bending tests were conducted on SHCC incorporated with various fly ash content. Two-parameter Weibull distribution was performed to analyze the variation of the results of SHCC after drop weight impact test under various curing ages from the perspective of reliability function. The cracking area ratio and fractal dimension were used to quantificationally investigate the failure characteristics of SHCC after the drop weight impact loading. Results indicate that the tensile, compressive, flexural strength and impact energy absorption capacity of SHCC decrease as the increasing of fly ash content. Impact ductility decreases slightly with the curing age. Single impact energy has an obvious effect on the impact resistance of SHCC, and it has a greater influence on the crack width at the initial cracking of SHCC than the crack width at failure. The two-parameter Weibull distribution can estimate the impact properties of SHCC by calculating the impact times at initial cracking and failure of SHCC. Cracking area ratio and fractal dimension can intuitively assess the impact failure characteristics of SHCC. Scanning electron microscopy images show that fibrillation and uneven scratches appear on the surface of the fibers, and the wavy texture can be observed in the axial direction of the fiber, indicating fiber pull-out is a typical failure pattern of the fiber under dynamic loading.

As a cyclometalated complex, solvent coligand Pt(II) complex with multiphoton absorption has been designed and synthesized. After the optical properties of the Pt(II) complex were studied carefully, time-dependent density functional theory calculation (TD-DFT) was used to further identify the triplet charge transitions of the complex. The specific energy levels of frontier molecular orbitals and the data related to the energy level transition showed that the Pt(II) complex had photoluminescent properties, and their phosphorescence emission originated from 3LLCT/3MLCT. Because of nonlinear optics (NLO) response, the Pt(II) complex could act as multiphoton absorption materials for bioimaging and anticancer application.

Abstract Designing new oxygenation nanomaterials by oxygen-generating or oxygen-carrying strategies in hypoxia-associated anti-tumor therapy is a high priority target yet challenge. In this work, we fabricated a nanoplatform involving Fenton-like reaction, Pd@MOF-525@HA, to relieve tumor hypoxia via oxygen-generating strategy for enhanced oxygen-dependent anti-tumor therapy. Thereinto, the porphyrinic MOF-525 can produce singlet oxygen (1O2) via light or ultrasonic irradiation for photodynamic and sonodynamic therapy. Notably, the well-dispersed Pd nanocubes within MOF-525 can convert H2O2 into O2 to mitigate the hypoxic environment for enhanced therapy outcome. Moreover, the two-photon activity and cancer cell specific targeting capability of Pd@MOF-525@HA gave rise to deeper tissue penetration and near-infrared light-induced fluorescence imaging to achieve precise guidance for cancer therapy. This work provides a feasible way in designing new oxygenation nanomaterials to relieve tumor hypoxia for enhanced cancer treatment. Graphical Abstract

Abstract Background The development of wearable health monitoring systems is garnering tremendous interest in research, technology and commercial applications. Their ability of providing unique capabilities in continuous, real-time, and non-invasive tracking of the physiological markers of users can provide insights into the performance and health of individuals. Electrocardiogram (ECG) signals are of particular interest, as cardiovascular disease is the leading cause of death globally. Monitoring heart health and its conditions such as ventricular disturbances and arrhythmias can be achieved through evaluating various features of ECG such as R-peaks, QRS complex, T-wave, and P-wave. Despite recent advances in biosensors for wearable applications, most of the currently available solutions rely solely on a single system attached to the body, limiting the ability to obtain reliable and multi-location biosignals. However, in engineering systems, sensor fusion, which is the optimal integration and processing of data from multiple sensors, has been a common theme and should be considered for wearables. In recent years, due to an increase in the availability and variety of different types of sensors, the possibility of achieving sensor fusion in wearable systems has become more attainable. Sensor fusion in multi-sensing systems results in significant enhancements of information inferences compared to those from systems with a sole sensor. One step towards the development of sensor fusion for wearable health monitoring systems is the accessibility to multiple reliable electrophysiological signals, which can be recorded continuously. Results In this paper, we develop a textile-based multichannel ECG band that has the ability to measure ECG from multiple locations on the waist. As a proof of concept, we demonstrate that ECG signals can be reliably obtained from different locations on the waist where the shape of the QRS complex is nearly comparable with recordings from the chest using traditional gel electrodes. In addition, we develop a probabilistic approach—based on prediction and update strategies—to detect R-peaks from noisy textile data in different statuses, including sitting, standing, and jogging. In this approach, an optimal search method is utilized to detect R-peaks based on the history of the intervals between previously detected R-peaks. We show that the performance of our probabilistic approach in R-peak detection is significantly better than that based on Pan–Tompkins and optimal-threshold methods. Conclusion A textile-based multichannel ECG band was developed to track the heart rate changes from multiple locations on the waist. We demonstrated that (i) the ECG signal can be detected from different locations on the waist, and (ii) the accuracy of the detected R-peaks from textile sensors was improved by using our proposed probabilistic approach. Despite the limitations of the textile sensors that might compromise the quality of ECG signals, we anticipate that the textile-based multichannel ECG band can be considered as an effective wearable system to facilitate the development of sensor fusion methodology for pervasive and non-invasive health monitoring through continuous tracking of heart rate variability (HRV) from the waist. In addition, from the commercialization point of view, we anticipate that the developed band has the potential to be integrated into garments such as underwear, bras or pants so that individuals can use it on a daily basis.

The presence of the phenol gossypol has severely limited the utilization of cottonseed meal and oil in the food and animal feed industries. Highly efficient means of biodegradation of gossypol and an understanding of the cytotoxicity of its degradation products remain outside current knowledge and are of universal interest. In this work, we showed for the first time that laccase can catalyze the intramolecular annulation of the aldehyde and hydroxyl groups of gossypol for the o-semiquinone radical and originate the released ·OH radical. It was further found that the oxidation of aldehyde groups significantly decreases reproductive toxicity and hepatotoxicity. These results indicate a novel detoxification pathway for gossypol and reveal the crucial role played by radical species in cyclization. This discovery could facilitate the development of safe, convenient, and low-cost industrial methods for the detoxification of cotton protein and oil resources.

The fracture energy of the high-performance fiber-reinforced cement-based composite (HPFRCC) can be modified within wide limits by the variation of the amount of steel fibers added to the fresh mix. First of all, considering the actual engineering conditions in Qingdao, the materials commonly used in Qingdao were selected. The optimal reference mix proportion of the HPFRCC cementing material was proposed through determination of fluidity and flexural strength. Based on the optimal mix proportion, the uniaxial tensile, fracture, and dry shrinkage properties of HPFRCC with different steel fibers are systematically studied. Stress-strain diagrams of the different samples were measured under the uniaxial tensile test, wedge splitting test, and three-point bending test. The steel fiber content was varied between 0 and 200 kg/m3. The load bearing capacity and the fracture energy were determined experimentally. In addition, moisture loss as a function of time and shrinkage was determined in an environment of 20°C and 50% RH (relative humidity). The results indicate that the maximum load increases significantly in the HPFRCC series reinforced by 150 and 200 kg/m3 of steel fibers. Both have a hardening branch developed after the first crack deflection due to the high percentage of fibers bridging the crack surfaces. The load bearing capacity and fracture energy increased almost linearly with the steel fiber content. It was found that the three-point bending test is more applicable in measuring the fracture energy of HPFRCC than the wedge splitting test. The addition of steel fibers decreased the moisture diffusion and consequently the drying shrinkage of HPFRCC, and there was minimum weight loss and deformation when the steel fiber content was 150 kg/m3. The results obtained will be presented and discussed.

The title compound, C24H18N4, crystallizes with three molecules in the asymmetric unit. In the crystal, weak C—H...π interactions link the molecules.

Although studies on water-repellent properties of silicon resin (SR) on cement-based materials have received tremendous attention around the world in recent years, they mainly focus on individual properties of water-repellent concrete treated with SR such as strength and water permeability resistance. However, to date, a systematic and comprehensive investigation is missing. The current study therefore investigates the influence of SR on the durability properties of cementitious materials by adding SR emulsion into integral concrete mixture and coating concrete surface with SR. The microscopic and mechanical properties and the durability performance were tested on the integral SR water‐repellent concrete (C-ISR) and SR surface water-repellent concrete (C-SSR). The obtained results indicate that SR application has no impact on hydration reaction and corresponding composition of cement-based materials, while SR addition leads to a reduction in strength and early shrinkage of cement mortar because the added SR delays the hydration reaction. Water-repellent treatment via SR can significantly reduce the water permeability of concrete, which is more apparent for surface water-repellent treatment (SSR). Furthermore, the durability properties were investigated, and the results indicate that integral SR water-repellent treatment (ISR) possesses better properties than SSR, which suggests water-repellent treatment via surface coating as an effective means to improve concrete durability.

An Ag/AgCl electrode used as a corrosion sensor in a reinforced concrete structure is considered as having good application prospect. However, its performance under complex conditions, such as dry-wet cycle condition, is not affirmed. In the current study, the performance of Ag/AgCl as chloride selective electrode in mortar exposed to dry-wet cycle condition was investigated. A simple Ag/AgCl electrode was prepared and fabricated by electrochemical anodization. These Ag/AgCl electrodes were embedded into a mortar specimen with temperature sensors, humidity sensors and anode ladder monitoring system (ALS). After 28 d curing time, the upper surface of mortar specimen was wetted (with 5% NaCl solution) and dried regularly. The obtained results indicate that Ag/AgCl electrode responds to the ingress of chloride ion, sensitively. The chloride ion concentration variation can be reflected by the potential trend. Furthermore, the balance potential of Ag/AgCl electrodes is influenced by dry-wet cycles. Compared with ALS, it demonstrates that Ag/AgCl electrodes are more sensitive to chloride. The research provides the key element for the specific application of Ag/AgCl electrode for corrosion monitoring in the future.

Recently, there is ongoing interest in the use of natural plant fibers as alternatives for conventional reinforcements in cementitious composites. The use of natural plant fibers makes engineering work more sustainable, since they are renewable, biodegradable, energy-efficient, and non-toxic raw materials. In this contribution, a comprehensive experimental program was undertaken to determine the influence of pineapple leaf fiber and ramie fiber on the mechanical properties and mass transport of cement-based composites. The compressive strength, tensile strength, modulus of elasticity, modulus of rupture, fracture energy, flexural toughness, coefficient of capillary water absorption, and chloride diffusion were measured. Natural plant fiber-reinforced cement-based composites (NPFRCCs) containing pineapple leaf fiber and ramie fiber, as compared to the plain control, exhibited a slight reduction in compressive strength and a considerable improvement in tensile strength, modulus of elasticity, modulus of rupture, and flexural toughness; the enhancement was remarkable with a higher fiber content. The coefficient of capillary absorption and chloride diffusion of NPFRCCs were significantly larger than the plain control, and the difference was evident with the increase in fiber content. The present study suggests that the specimen with 2% pineapple leaf fiber content can be used in normal environments due to its superior mechanical properties. However, one should be careful when using the material in marine environments.

Four novel ZnII coordination polymers, [(ZnCl2)2(L)2]n (1), [(ZnBr2)2(L)2]n (2), and [(ZnI2)2(L)2]n (3) and {[Zn(SCN)2]1.5(L)3}n (4), have been synthesized based on 4′-ferrocenyl-3,2′:6′,3′′-terpyridine with ZnII ions and different coordination anions under similar ambient conditions. Their structures have been confirmed using single crystal X-ray diffraction analysis, showing that complexes 1–3 are one-dimensional (1D) double-stranded metal ion helical polymer chains and complex 4 is of a two-dimensional (2D) network. The structural transformations of them from a 1D polymer chain to a 2D network under the influence of the coordination anions has been systematic investigated. Furthermore, the optical band gaps have been measured by optical diffuse reflectance spectroscopy, revealing that the ligand and the complexes should have semiconductor properties.

The application of two-photon absorption (2PA) materials is a classical research field and has recently attracted increasing interest. It has generated a demand for new dyes with high 2PA cross-sections. In this short review, we briefly cover the structure-2PA property relationships of organic fluorophores, organic-inorganic nanohybrids and metal complexes explored by our group. (1) The two-photon absorption cross-section (δ) of organic fluorophores increases with the extent of charge transfer, which is important to optimize the core, donor-acceptor pair, and conjugation-bridge to obtain a large δ value. Among the various cores, triphenylamine appears to be an efficient core. Lengthening of the conjugation with styryl groups in the D-π-D quadrupoles and D-π-A dipoles increased δ over a long wavelength range than when vinylene groups were used. Large values of δ were observed for extended conjugation length and moderate donor-acceptors in the near-IR wavelengths. The δ value of the three-arm octupole is larger than that of the individual arm, if the core has electron accepting groups that allow significant electronic coupling between the arms; (2) Optical functional organic/inorganic hybrid materials usually show high thermal stability and excellent optical activity; therefore the design of functional organic molecules to build functional organic-inorganic hybrids and optimize the 2PA properties are significant. Advances have been made in the design of organic-inorganic nanohybrid materials of different sizes and shapes for 2PA property, which provide useful examples to illustrate the new features of the 2PA response in comparison to the more thoroughly investigated donor-acceptor based organic compounds and inorganic components; (3) Metal complexes are of particular interest for the design of new materials with large 2PA ability. They offer a wide range of metals with different ligands, which can give rise to tunable electronic and 2PA properties. The metal ions, including transition metals and lanthanides, can serve as an important part of the structure to control the intramolecular charge-transfer process that drives the 2PA process. As templates, transition metal ions can assemble simple to more sophisticated ligands in a variety of multipolar arrangements resulting in interesting and tailorable electronic and optical properties, depending on the nature of the metal center and the energetics of the metal-ligand interactions, such as intraligand charge-transfer (ILCT) and metal-ligand charge-transfer (MLCT) processes. Lanthanide complexes are attractive for a number of reasons: (i) their visible emissions are quite long-lived; (ii) their absorption and emission can be tuned with the aid of appropriate photoactive ligands; (iii) the accessible energy-transfer path between the photo-active ligands and the lanthanide ion can facilitate efficient lanthanide-based 2PA properties. Thus, the above materials with excellent 2PA properties should be applied in two-photon applications, especially two-photon fluorescence microscopy (TPFM) and related emission-based applications. Furthermore, the progress of research into the use of those new 2PA materials with moderate 2PA cross section in the near-infrared region, good Materials 2017, 10, 223 2 of 37 biocompatibility, and enhanced two-photon excited fluorescence for two-photon bio-imaging is summarized. In addition, several possible future directions in this field are also discussed (146 references).