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Gastrointestinal cancer is among the most common cancers worldwide. Immune checkpoint inhibitor-based cancer immunotherapy has become an innovative approach in cancer treatment; however, its efficacy in gastrointestinal cancer is limited by the absence of infiltration of immune cells within the tumor microenvironment. Therefore, it is therefore urgent to develop a novel therapeutic drug to enhance immunotherapy. In this study, we describe a previously unreported potentiating effect of Icariside I (ICA I, GH01), the main bioactive compound isolated from the Epimedium species, on anti-tumor immune responses. Mechanistically, molecular docking and SPR assay result show that ICA I binding with TRPV4. ICA I induced intracellular Ca2+ increasing and mitochondrial DNA release by targeting TRPV4, which triggered cytosolic ox-mitoDNA release. Importantly, these intracellular ox-mitoDNA fragments were taken up by immune cells in the tumor microenvironment, which amplified the immune response. Moreover, our study shows the remarkable efficacy of sequential administration of ICA I and anti-α-PD-1 mAb in advanced tumors and provides a strong scientific rationale for recommending such a combination therapy for clinical trials. ICA I enhanced the anti-tumor effects with PD-1 inhibitors by regulating the TRPV4/Ca2+/Ox-mitoDNA/cGAS/STING axis. We expect that these findings will be translated into clinical therapies, which will benefit more patients with cancer in the near future.

Abstract Solar panels often suffer from dust accumulation, significantly reducing their output, especially in desert regions where many of the world's largest solar plants are located. Here, an autonomous dust removal system for solar panels, powered by a wind‐driven rotary electret generator is proposed. The generator applies a high voltage between one solar panel's output electrode and an upper mesh electrode to generate a strong electrostatic field. It is discovered that dust particles on the insulative glass cover of the panel can be charged under the high electrical field, assisted by adsorbed water, even in low‐humidity environments. The charged particles are subsequently repelled from the solar panel with the significant Coulomb force. Two panels covered with sand dust are cleaned in only 6.6 min by a 15 cm diameter rotary electret generator at 1.6 m s−1 wind speed. Experimental results manifest that the system can work effectively in a wide range of environmental conditions, and doesn't impact the panel performance for long‐term operation. This autonomous system, with its high dust removal efficiency, simplicity, and low cost, holds great potential in practical applications.

Objectives: The role of Epoxide Hydrolase-4 (EPHX4), a member of epoxide hydrolase family, has not been investigated in cancer. The purpose of this article is to explore the application value of EPHX4 in laryngeal cancer and its relationship with immune infiltration. Methods: We observed that EPHX4 expression and its survival assays in laryngeal cancer specimens based on The Cancer Genome Atlas (TCGA) cohorts. We also analyzed the correlation between immune cell infiltration levels and EPHX4 gene copy number in laryngeal cancer. Finally, we conducted in vitro assay to evaluate the functions of EPHX4 in laryngeal cancer cell line. Results: EPHX4 is highly expressed in laryngeal cancer specimens and has a poor prognosis. EPHX4 related immune cell analysis showed that it participated in NK Natural killer cell mediated cytotoxicity. Finally, Cell experiments indicate that EPHX4 could promote laryngeal cancer cell line proliferation, colony formation and invasion. Conclusions: Our research results suggest that EPHX4 may be a potential immunotherapy target for laryngeal cancer. The nominated immune signature is a helpful and promising prognostic indicator in laryngeal cancer. Levels of Evidence: Level 3.

The unique gradient structure and complex composition of osteochondral tissue pose significant challenges in defect regeneration. Restoration of tissue heterogeneity while maintaining hyaline cartilage components has been a difficulty of an osteochondral tissue graft. A novel class of multi-crosslinked polysaccharide-based three-dimensional (3D) printing inks, including decellularized natural cartilage (dNC) and nano-hydroxyapatite, was designed to create a gradient scaffold with a robust interface-binding force. Herein, we report combining a dual-nozzle cross-printing technology and a gradient crosslinking method to create the scaffolds, demonstrating stable mechanical properties and heterogeneous bilayer structures. Biofunctional assessments revealed the remarkable regenerative effects of the scaffold, manifesting three orders of magnitude of mRNA upregulation during chondrogenesis and the formation of pure hyaline cartilage. Transcriptomics of the regeneration site in vivo and scaffold cell interaction tests in vitro showed that printed porous multilayer scaffolds could form the correct tissue structure for cell migration. More importantly, polysaccharides with dNC provided a hydrophilic microenvironment. The microenvironment is crucial in osteochondral regeneration because it could guide the regenerated cartilage to ensure the hyaline phenotype.

Wearable and stretchable strain sensors have potential values in the fields of human motion and health monitoring, flexible electronics, and soft robotic skin. The wearable and stretchable strain sensors can be directly attached to human skin, providing visualized detection for human motions and personal healthcare. Conductive polymer composites (CPC) composed of conductive fillers and flexible polymers have the advantages of high stretchability, good flexibility, superior durability, which can be used to prepare flexible strain sensors with large working strain and outstanding sensitivity. This review has put forward a comprehensive summary on the fabrication methods, advanced mechanisms and strain sensing abilities of CPC strain sensors reported in recent years, especially the sensors with superior performance. Finally, the structural design, bionic function, integration technology and further application of CPC strain sensors are prospected.

Bacterial cellulose (BC) has been recognized as an ideal supporter owning to its abundant hydroxyl groups on the surface. In this work, Keggin-type phosphotungstic acid (H3PW12O40, PWA) is self-anchored on the three-dimensional network of BC by a simple diffusion method at room-temperature. BC fibers can protect the well-dispersed PWA with high transparency, high mechanical strength, and high stability. When PWA/BC serves as a photochromic material, the coloration time and bleaching time are only 3 min and 30 min respectively. After 6 cycles, the photochromic ability of the PWA/BC composite film almost unchanged. At the same time, we convert the coloration and bleaching degree into quantitative data including a color difference calculation of ΔE2000 and the remaining degree of color (RC%). Within the BC system, PWA exhibits a special linear relationship between RC% and bleaching time (0–30 min). The processes of PWA/BC reduction (W6+→W5+) and oxidation (W5+→W6+) are analysed by photo-electrochromic, XPS and ESR characterizations. The revealed excellent photochromic properties of soft PWA/BC films highlight their potential as the photoresponsive materials.

Our research objective is to establish a fuzzy evaluation mechanism for rural village officials in China using the theory of triangular multiplication preference relationships. Our survey targets villagers in rural areas of China where village autonomy is implemented. The research methods include a questionnaire survey, Delphi, and fuzzy evaluation methods. After research analysis and comparison of results, it is shown that for the evaluation index system of village officials constructed using the Delphi method, practical evaluation of village officials can be achieved through fuzzy comprehensive evaluation based on triangular multiplication preference relationships. Using the Delphi technique, this article first created a village official assessment index system. It then performed validity tests based on the Kaiser-Meyer-Olkin (KMO) and Bartlett index system, as well as reliability testing using the Cronbach coefficient. Then, the preference relationship of triangular multiplication and the root product square method were used to determine the weight of the questionnaire indicators, and consistency was judged. Then, based on the membership function, the fuzzy boundaries of various indicators are displayed to construct a fuzzy evaluation matrix. Finally, the evaluation matrix is subjected to the Zadeh operation to obtain a fuzzy, comprehensive evaluation result of the work performance of village officials. Our main contribution is establishing an evaluation index system for village officials through the Delphi method and achieving a practical evaluation of village officials using triangular multiplication preference relationships and fuzzy evaluation theory.

Abstract Background Internet of things (IoT) has been used in many places. IoT make devices connected to the Internet via sensor devices to achieve the interconnection between things and things, people and things. Sybil attacker attacks IoT by imitating the identity of users. Few methods are applicable for mobile IoT in previous Sybil attack detecting methods, while the methods are mainly focus on static IoT. Results A distributive and lightweight Sybil attack detection scheme in the mobile IoT is proposed in this paper. This scheme works around received signal strength indications (RSSI). The scheme consists of two rounds. Identity information is sent from member nodes to edge nodes in both of the two rounds. In the first round edge, nodes calculate the possible RSSI interval for each member node; in the second round, they check the RSSI value of member nodes to detect Sybil attacks. Intelligent algorithms are used to predict the position of member nodes, which makes the theoretical interval more accurate. Extensive experimental studies show that in the true and false detection rate, this scheme is superior to many existing schemes.

Abstract Limited by preparation time and ligand solubility, synthetic protocols for cyclodextrin‐based metal‐organic framework (CD‐MOF), as well as subsequent derived materials with improved stability and properties, still remains a challenge. Herein, an ultrafast, environmentally friendly, and cost‐effective microwave method is proposed, which is induced by graphene oxide (GO) to design CD‐MOF/GOs. This applicable technique can control the crystal size of CD‐MOFs from macro‐ to nanocrystals. CD‐MOF/GOs are investigated as a new type of supramolecular adsorbent. It can selectively adsorb the dye molecule methylene green (MG) owing to the synergistic effect between the hydrophobic nanocavity of CDs, and the abundant O‐containing functional groups of GO in the composites. Following high temperature calcination, the resulting N, S co‐doped porous carbons derived from CD‐MOF/GOs exhibit a high capacitance of 501 F g−1 at 0.5 A g−1, as well as stable cycling stability with 90.1% capacity retention after 5000 cycles. The porous carbon exhibits good electrochemical performance due to its porous surface containing numerous electrochemically active sites after dye adsorption and carbonization. The design strategy by supramolecular incorporating a variety of active molecules into CD‐MOFs optimizes the properties of their derived materials, furthering development toward the fabrication of zeitgeisty and high‐performance energy storage devices.

Abstract Real‐time monitoring of vital sounds from cardiovascular and respiratory systems via wearable devices together with modern data analysis schemes have the potential to reveal a variety of health conditions. Here, a flexible piezoelectret sensing system is developed to examine audio physiological signals in an unobtrusive manner, including heart, Korotkoff, and breath sounds. A customized electromagnetic shielding structure is designed for precision and high‐fidelity measurements and several unique physiological sound patterns related to clinical applications are collected and analyzed. At the left chest location for the heart sounds, the S1 and S2 segments related to cardiac systole and diastole conditions, respectively, are successfully extracted and analyzed with good consistency from those of a commercial medical device. At the upper arm location, recorded Korotkoff sounds are used to characterize the systolic and diastolic blood pressure without a doctor or prior calibration. An Omron blood pressure monitor is used to validate these results. The breath sound detections from the lung/ trachea region are achieved a signal‐to‐noise ration comparable to those of a medical recorder, BIOPAC, with pattern classification capabilities for the diagnosis of viable respiratory diseases. Finally, a 6×6 sensor array is used to record heart sounds at different locations of the chest area simultaneously, including the Aortic, Pulmonic, Erb's point, Tricuspid, and Mitral regions in the form of mixed data resulting from the physiological activities of four heart valves. These signals are then separated by the independent component analysis algorithm and individual heart sound components from specific heart valves can reveal their instantaneous behaviors for the accurate diagnosis of heart diseases. The combination of these demonstrations illustrate a new class of wearable healthcare detection system for potentially advanced diagnostic schemes.

Abstract The geometric designs of MEMS devices can profoundly impact their physical properties and eventual performances. However, it is challenging for researchers to rationally consider a large number of possible designs, as it would be very time- and resource-consuming to study all these cases using numerical simulation. In this paper, we report the use of deep learning techniques to accelerate the MEMS design cycle by quickly and accurately predicting the physical properties of numerous design candidates with vastly different geometric features. Design candidates are represented in a nonparameterized, topologically unconstrained form using pixelated black-and-white images. After sufficient training, a deep neural network can quickly calculate the physical properties of interest with good accuracy without using conventional numerical tools such as finite element analysis. As an example, we apply our deep learning approach in the prediction of the modal frequency and quality factor of disk-shaped microscale resonators. With reasonable training, our deep learning neural network becomes a high-speed, high-accuracy calculator: it can identify the flexural mode frequency and the quality factor 4.6 × 103 times and 2.6 × 104 times faster, respectively, than conventional numerical simulation packages, with good accuracies of 98.8 ± 1.6% and 96.8 ± 3.1%, respectively. When simultaneously predicting the frequency and the quality factor, up to ~96.0% of the total computation time can be saved during the design process. The proposed technique can rapidly screen over thousands of design candidates and promotes experience-free and data-driven MEMS structural designs.

In recent decades, memory-intensive applications have experienced a boom, e.g., machine learning, natural language processing (NLP), and big data analytics. Such applications often experience out-of-memory (OOM) errors, which cause unexpected processes to exit without warning, resulting in negative effects on a system’s performance and stability. To mitigate OOM errors, many operating systems implement memory compression (e.g., Linux’s ZRAM) to provide flexible and larger memory space. However, these schemes incur two problems: (1) high-compression algorithms consume significant CPU resources, which inevitably degrades application performance; and (2) compromised compression algorithms with low latency and low compression ratios result in insignificant increases in memory space. In this paper, we propose QZRAM, which achieves a high-compression-ratio algorithm without high computing consumption through the integration of QAT (an ASIC accelerator) into ZRAM. To enhance hardware and software collaboration, a page-based parallel write module is introduced to serve as a more efficient request processing flow. More importantly, a QAT offloading module is introduced to asynchronously offload compression to the QAT accelerator, reducing CPU computing resource consumption and addressing two challenges: long CPU idle time and low usage of the QAT unit. The comprehensive evaluation validates that QZRAM can reduce CPU resources by up to 49.2% for the FIO micro-benchmark, increase memory space (1.66×) compared to ZRAM, and alleviate the memory overflow phenomenon of the Redis benchmark.

Metro stations are considered high-quality resources for promoting urban development, which have great influences on the surrounding land use changes. The simulation and prediction of land use change can provide a scientific basis for urban land planning. In this work, the cellular automata (CA)-Markov model was adopted by taking into account point of interest (POI) kernel density and station accessibility as driving factors to predict the land use change of station surrounding areas. Then, the land type compositions of different years, temporal and spatial evolution of landscape patterns, and strategies of different metro stations were explored. The results show that the Kappa coefficients of the Zoo Station and the Lu Xiao Station are 87% and 79%, respectively, indicating that the improved CA-Markov model can predict land use changes more accurately by considering POI kernel density and station accessibility. Finally, different optimized strategies based on systematic predictions of land use landscape patterns according to the spatial and temporal distribution of metro stations were proposed. The work provides important references for predicting the impact of new metro stations on land use in the future and guides the adjustment and optimization of land use policy planning.

The wound healing process is usually susceptible to different bacterial infections due to the complex physiological environment, which significantly impairs wound healing. The topical application of antibiotics is not desirable for wound healing because the excessive use of antibiotics might cause bacteria to develop resistance and even the production of super bacteria, posing significant harm to human well-being. Wound dressings based on adhesive, biocompatible, and multi-functional hydrogels with natural antibacterial agents have been widely recognized as effective wound treatments. Hydrogels, which are three-dimensional (3D) polymer networks cross-linked through physical interactions or covalent bonds, are promising for topical antibacterial applications because of their excellent adhesion, antibacterial properties, and biocompatibility. To further improve the healing performance of hydrogels, various modification methods have been developed with superior biocompatibility, antibacterial activity, mechanical properties, and wound repair capabilities. This review summarizes hundreds of typical studies on various ingredients, preparation methods, antibacterial mechanisms, and internal antibacterial factors to understand adhesive hydrogels with natural antibacterial agents for wound dressings. Additionally, we provide prospects for adhesive and antibacterial hydrogels in biomedical applications and clinical research.

Moisture-induced energy generation is a potential green energy power source. Here, the authors report a moisture-induced autonomous surface potential oscillation phenomenon and apply it to the demonstration of energy harvesters with long persistence time and good energy density

A pH-responsive curcuminoid delivery system based on supramolecular vesicles was fabricated via a novel host–guest inclusion complex between water-soluble pillar[5]arene (WP5) and hydrophobic bisdemethoxycurcumin (BDMC). This WP5 and BDMC (WP5 ⊃ BDMC) inclusion complex was studied using 1H NMR, UV–vis, and fluorescence spectroscopy. This resulting inclusion complex could self-assemble into well-defined supramolecular vesicles by host–guest interactions and presented a significant pH-responsive behavior, which was investigated using dynamic laser scattering, transmission electron microscopy, and UV–vis spectroscopy. The suitable preservation time for WP5 ⊃ BDMC and the construction ratio between host/guest molecules were both of great significance for the aggregated morphology of supramolecular vesicles. Furthermore, the BDMC complexes showed good anticancer ability in vitro, as they could inhibit HepG2 cell proliferation and migration. Therefore, the curcuminoid vesicles could provide a promising platform for drug delivery or food packaging utilization.

Vulcanization is an essential process to obtain high-performance rubber products. Diphenylguanidine (DPG) is often used as the secondary accelerator in the vulcanization process of natural rubber (NR) latex. However, DPG would make NR latex emulsion exhibit gelation, resulting in the negative vulcanization efficiency. In addition, exposure to DPG might lead to some physiological diseases during the production process of DPG doped NR latex. Hydroxypropyl-β-cyclodextrin (HP-β-CD) with the hydrophobic interior and hydrophilic exterior has the advantages of good water solubility, high bioavailability, reliable stability, and low toxicity. In this study, the inclusion complex of diphenylguanidine-hydroxypropyl-β-cyclodextrin (DPG-HP-β-CD) is prepared by ball milling with a host-guest molar ratio of 1 : 1, which has also been applied to the foaming process of NR latex. The mechanical properties of DPG-HP-β-CD inclusion complex/natural rubber latex foam (DPG-HP-β-CD/NRLF) have been significantly improved, including the tensile strength, elongation at break, hardness, compression set, resilience, and antiaging performance. Further, the usage of DPG has been reduced, leading to the reduction of toxicity and environmental hazards.

The utilizations of microfluidic chips for single RBC (red blood cell) studies have attracted great interests in recent years to filter, trap, analyze, and release single erythrocytes for various applications. Researchers in this field have highlighted the vast potential in developing micro devices for industrial and academia usages, including lab-on-a-chip and organ-on-a-chip systems. This article critically reviews the current state-of-the-art and recent advances of microfluidics for single RBC analyses, including integrated sensors and microfluidic platforms for microscopic/tomographic/spectroscopic single RBC analyses, trapping arrays (including bifurcating channels), dielectrophoretic and agglutination/aggregation studies, as well as clinical implications covering cancer, sepsis, prenatal, and Sickle Cell diseases. Microfluidics based RBC microarrays, sorting/counting and trapping techniques (including acoustic, dielectrophoretic, hydrodynamic, magnetic, and optical techniques) are also reviewed. Lastly, organs on chips, multi-organ chips, and drug discovery involving single RBC are described. The limitations and drawbacks of each technology are addressed and future prospects are discussed.

A gelatin/sodium alginate-based hydrogel microsphere has been fabricated after reaction condition optimization. Macrophages (RAW246.7) and adipose mesenchymal stem cells (ADSC) have been subsequently encapsulated in the microsphere in order to construct a 3D paracrine system for wound healing treatment. The synthesized microsphere displayed neglectable cytotoxicity toward both encapsulated cells until 10 days of incubation, indicating promising biocompatibility of the microsphere. A qRT-PCR and ELISA experiment revealed positive regulation of cytokines (Arg-1, IL-6, IL-8, IL-10, bFGF, HGF, VEGF, TLR-1, and CXCL13) expression regarding macrophage phenotype transformation and anti-inflammatory performance both inside the microsphere and in the microenvironment of established in vitro inflammatory model. Additionally, positive tendency of cytokine expression benefit wound healing was more pronounced in a fabricated 3D paracrine system than that of a 2D paracrine system. Furthermore, the 3D paracrine system exhibited more efficiently in the wound healing rate compared to the 2D paracrine system in an in vitro model. These results suggested the current paracrine system could be potentially used as a robust wound healing dressing.

Diphenylguanidine (DPG) is a widely used secondary accelerator for the vulcanization of natural rubber (NR) latex. However, its low water solubility and high toxicity limit its use in high-end NR products. In this study, a water-soluble inclusion complex of DPG and a β-cyclodextrin polymer (β-CDP), termed DPG-β-CDP, was prepared through supramolecular interactions and characterized using Fourier-transform infrared spectroscopy, 1H NMR, scanning electron microscopy, and UV-vis spectroscopy techniques. In comparison with that of DPG, the water solubility of DPG-β-CDP was greatly enhanced because of the water-soluble host molecule. The molar ratio of DPG to the CD unit in β-CDP was determined to be 1:1. At 25 °C, the binding constant of DPG-β-CDP was found to be 9.2 × 105 L/mol by UV-vis spectroscopy. The proposed method for forming inclusion complexes with high potential for use as water-soluble vulcanization accelerators is promising.

Transition metal carbides are attractive for electrochemical energy storage and catalysis, but cost effective preparation on a large scale is challenging. Here the authors use a direct pattern method to fabricate transition metal carbides for supercapacitors and solar energy harvesting for steam generation.

Abstract Wafer-scale, conformal, two-dimensional (2D) TiO2-Ga2O3 n-p heterostructures with a thickness of less than 10 nm were fabricated on the Si/SiO2 substrates by the atomic layer deposition (ALD) technique for the first time with subsequent post-deposition annealing at a temperature of 250 °C. The best deposition parameters were established. The structure and morphology of 2D TiO2-Ga2O3 n-p heterostructures were characterized by the scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), etc. 2D TiO2-Ga2O3 n-p heterostructures demonstrated efficient photocatalytic activity towards methyl orange (MO) degradation at the UV light (λ = 254 nm) irradiation. The improvement of TiO2-Ga2O3 n-p heterostructure capabilities is due to the development of the defects on Ga2O3-TiO2 interface, which were able to trap electrons faster. Graphical Abstract

The publication of trajectory data provides critical information for various location-based services, and it is critical to publish trajectory data safely while ensuring its availability. Differential privacy is a promising privacy protection technology for publishing trajectory data securely. Most of the existing trajectory privacy protection schemes do not take into account the user’s preference for location and the influence of semantic location. Besides, differential privacy for trajectory protection still has the problem of balance between the privacy budget and service quality. In this paper, a semantics- and prediction-based differential privacy protection scheme for trajectory data is proposed. Firstly, trajectory data are transformed into a prefix tree structure to ensure that they satisfy differential privacy. Secondly, considering the influence of semantic location on trajectory, semantic sensitivity combined with location check-in frequency is used to calculate the sensitivity of each position in the trajectory. The privacy level of the position is classified by setting thresholds. Moreover, the corresponding privacy budget is allocated according to the location privacy level. Finally, a Markov chain is used to predict the attack probability of each position in the trajectory. On this basis, the allocation of the privacy budget is further adjusted and its utilization rate is improved. Thus, the problem of the balance between the privacy budget and service quality is solved. Experimental results show that the proposed scheme is able to ensure data availability while protecting data privacy.

Electrospinning setup with a sharp tip guiding electrode has been designed for high-aspect-ratio three-dimensional (3D) electrospinning by enhancing the electrical field strength to guide nanofibers toward designated paths layer by layer. This setup helps to deposit nanofibers under a steady charge transfer process and overcomes the electrical interferences. The polymer jet via the electrohydrodynamic process has been used to direct-write ordered, 3D structures with the aspect-ratio (height/width) up to 25 for various patterns, such as rectangular grids and five-point stars. Experimental results show the deposited nanofibers can form 3D high-aspect-ratio structures with uniform nanofiber diameter and good position accuracy higher than 1.5 μm.

Multi-jet electrospinning arranged in an arc array with sheath gas has been developed for the high-efficiency production of nanofiber membranes. The arc array constrains the electric field interferences among multiple nozzles and the sheath gas in laminar flow overcomes the electric repulsive force among the jets. The stretching and focusing effect from the sheath gas reduces both the nanofiber diameter and the diameter range, which helps to realize the continuous stable multi-jet electrospinning to fabricate uniform nanofiber membranes. After the treatment of 98% concentrated sulfuric acid for the reactive exchange groups and a hot-pressing process, the membrane is then applicable to electrodialysis applications. Thanks to the net structure, there are many ion transmission passageways within the membrane, leading to the low membrane resistance and high ion transmission efficiency. Experimentally, the increase of membrane thickness results in the decrease of porosity, ion exchange capacity (IEC) and selective permeability and the increase in membrane resistance. The electrodialysis tests show good ion selection performance with a high desalinization ratio of NaCl solution. Keywords: Multi-jet electrospinning, Nanofiber membrane, Electrodialysis, Sheath gas

Wearable supercapacitors based on carbon materials have been emerging as an advanced technology for next-generation portable electronic devices with high performance. However, the application of these devices cannot be realized unless suitable flexible power sources are developed. Here, an effective electrospinning method was used to prepare the one-dimensional (1D) and nano-scale carbon fiber membrane based on potassium citrate/polyacrylonitrile (PAN), which exhibited potential applications in supercapacitors. The chemical and physical properties of carbon nanofibers were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and the Brunnauer–Emmett–Teller method. The fabricated carbon nanofiber membrane illustrates a high specific capacitance of 404 F/g at a current density of 1 A/g. The good electrochemical properties could be attributed to the small diameter and large specific surface area, which promoted a high capacity.

This paper describes a generative design methodology for a micro hydrodynamic single-RBC (red blood cell) trap for applications in microfluidics-based single-cell analysis. One key challenge in single-cell microfluidic traps is to achieve desired through-slit flowrates to trap cells under implicit constraints. In this work, the cell-trapping design with validation from experimental data has been developed by the generative design methodology with an evolutionary algorithm. L-shaped trapping slits have been generated iteratively for the optimal geometries to trap living-cells suspended in flow channels. Without using the generative design, the slits have low flow velocities incapable of trapping single cells. After a search with 30,000 solutions, the optimized geometry was found to increase the through-slit velocities by 49%. Fabricated and experimentally tested prototypes have achieved 4 out of 4 trapping efficiency of RBCs. This evolutionary algorithm and trapping design can be applied to cells of various sizes.

Tetrapod quantum dots are promising nanoscale stress sensors because of their non-invasive sensing technique, but sensor versatility has not yet been assessed. Here the authors show that tetrapod quantum dots exhibit a large dynamic range and excellent sensing versatility in a multitude of polymers.

Abstract Flexible power sources with load bearing capability are attractive for modern wearable electronics. Here, free-standing supercapacitor fabrics that can store high electrical energy and sustain large mechanical loads are directly woven to be compatible with flexible systems. The prototype with reduced package weight/volume provides an impressive energy density of 2.58 mWh g−1 or 3.6 mWh cm−3, high tensile strength of over 1000 MPa, and bearable pressure of over 100 MPa. The nanoporous thread electrodes are prepared by the activation of commercial carbon fibers to have three-orders of magnitude increase in the specific surface area and 86% retention of the original strength. The novel device configuration woven by solid electrolyte-coated threads shows excellent flexibility and stability during repeated mechanical bending tests. A supercapacitor watchstrap is used to power a liquid crystal display as an example of load-bearing power sources with various form-factor designs for wearable electronics.

Abstract Heterogeneous TiO2@Nb2O5 composites, in which TiO2 nanoparticles were evenly embedded on ultrathin Nb2O5 nanosheets, were used as anode materials for LIBs and demonstrated high capacities and excellent rate capability. For instance, this material displayed large capacities of 166.3 and 129.1 mA h g−1 at current densities of 1 A g−1 after 100 cycles and 5 A g−1 after 300 cycles, respectively.

Abstract This paper presents a bio-inspired adaptive micro-lens with electrically tunable focus made of non-ionic high-molecular-weight polyvinyl chloride (PVC) gel. The optical device mimics the design of the crystalline lens and ciliary muscle of the human eye. It consists of a plano-convex PVC gel micro-lens on Indium Tin Oxide (ITO) glass, confined with an annular electrode operating as an artificial ciliary muscle. Upon electrical activation, the electroactive adhesive force of the PVC gel is exerted on the annular anode electrode, which reduces the sagittal height of the plano-convex PVC gel lens, resulting in focal length variation of the micro-lens. The focal length increases from 3.8 mm to 22.3 mm as the applied field is varied from 200 V/mm to 800 V/mm, comparable to that of the human lens. The device combines excellent optical characteristics with structural simplicity, fast response speed, silent operation, and low power consumption. The results show the PVC gel micro-lens is expected to open up new perspectives on practical tunable optics.

Photocatalytic water splitting represents an emerging technology well positioned to satisfy the growing need for low-energy, low CO2, economically viable hydrogen gas production. As such, stable, high-surface-area electrodes are increasingly being investigated as electrodes for the photochemical conversion of solar energy into hydrogen fuel. We present a titanium dioxide (TiO2)/zinc oxide (ZnO) nanowire array using a hybrid hydrothermal/atomic layer deposition (ALD) for use as a solar-powered photoelectrochemical device. The nanowire array consists of single crystalline, wurtzite ZnO nanowires with a 40 nm ALD TiO2 coating. By using a TiO2 nanocoating on the high surface area-ZnO array, three advancements have been accomplished in this work: (1) high aspect ratio nanowires with TiO2 for water splitting (over 8 μm), (2) improved stability over bare ZnO nanowires during photocatalysis, and (3) excellent onset voltage. As such, this process opens up new class of the micro/nanofabrication process for making efficient photocatalytic gas harvesting systems.

Recent years have seen the wide application of Location-Based Services (LBSs) in our daily life. Although users can enjoy many conveniences from the LBSs, they may lose their trajectory privacy when their location data are collected. Therefore, it is urgent to protect the user’s trajectory privacy while providing high quality services. Trajectory k-anonymity is one of the most important technologies to protect the user’s trajectory privacy. However, the user’s attributes are rarely considered when constructing the k-anonymity set. It results in that the user’s trajectories are especially vulnerable. To solve the problem, in this paper, a Spatiotemporal Mobility (SM) measurement is defined for calculating the relationship between the user’s attributes and the anonymity set. Furthermore, a trajectory graph is designed to model the relationship between trajectories. Based on the user’s attributes and the trajectory graph, the SM based trajectory privacy-preserving algorithm (MTPPA) is proposed. The optimal k-anonymity set is obtained by the simulated annealing algorithm. The experimental results show that the privacy disclosure probability of the anonymity set obtained by MTPPA is about 40% lower than those obtained by the existing algorithms while the same quality of services can be provided.

Please be advised that the name of one of the coauthors in the original article [1] has been incorrectly spelled: ‘Ranish M. Ramachandran’ should be ‘Ranjith K. Ramachandran’.

Hydroxyapatite (HA), a typical inorganic component of bone, is a widely utilized biomaterial for bone tissue repair and regeneration due to its excellent properties. Inspired by the recent findings on the important roles of protein in biomineralization and natural structure of fish scales, keratin was chosen as a template for modulating the assembly of HA nanocrystals. A series of HA nanocrystals with different sizes were synthesized by adjusting the concentration of partially hydrolyzed keratin. The structure and compositions of the prepared HA were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman spectrum, and Transmission electron microscopy (TEM). Results revealed that the size of the synthesized HA nanocrystals can be controlled by adjusting the concentration of partially hydrolyzed keratin. Specifically, the size of synthesized HA decreased from 63 ± 1.5 nm to 27 ± 0.9 nm with the increasing concentration of partially hydrolyzed keratin from 0 to 0.6g. In addition, in vitro cytocompatibility of synthesized HA nanocrystals were evaluated using the MG-63 cells.

Ammonia gas sensors are very essential in many industries and everyday life. However, their complicated fabrication process, severe environmental fabrication requirements and desorption of residual ammonia molecules result in high cost and hinder their market acceptance. Here, laser direct writing is used to fabricate three parallel porous 3D graphene lines on a polyimide (PI) tape to simply construct an ammonia gas sensor. The middle one works as an ammonia sensing element and the other two on both sides work as heaters to improve the desorption performance of the sensing element to ammonia gas molecules. The graphene lines were characterized by scanning electron microscopy and Raman spectroscopy. The response and recovery time of the sensor without heating are 214 s and 222 s with a sensitivity of 0.087% ppm−1 for sensing 75 ppm ammonia gas, respectively. The experimental results prove that under the optimized heating temperature of about 70 °C the heaters successfully help implement complete desorption of residual NH3 showing a good sensitivity and cyclic stability.

Ultra-low pressure measurement is necessary in many areas, such as high-vacuum environment monitoring, process control and biomedical applications. This paper presents a novel approach for ultra-low pressure measurement where capacitive micromachined ultrasonic transducers (CMUTs) are used as the sensing elements. The working principle is based on the resonant frequency shift of the membrane under the applied pressure. The membranes of the biased CMUTs can produce a larger resonant frequency shift than the diaphragms with no DC bias in the state-of-the-art resonant pressure sensors, which contributes to pressure sensitivity improvement. The theoretical analysis and finite element method (FEM) simulation were employed to study the relationship between the resonant frequency and the pressure. The results demonstrated excellent capability of the CMUTs for ultra-low pressure measurement. It is shown that the resonant frequency of the CMUT varies linearly with the applied pressure. A sensitivity of more than 6.33 ppm/Pa (68 kHz/kPa) was obtained within a pressure range of 0 to 100 Pa when the CMUTs were biased at a DC voltage of 90% of the collapse voltage. It was also demonstrated that the pressure sensitivity can be adjusted by the DC bias voltage. In addition, the effects of air damping and ambient temperature on the resonant frequency were also studied. The effect of air damping is negligible for the pressures below 1000 Pa. To eliminate the temperature effect on the resonant frequency, a temperature compensating method was proposed.

The online and accurate monitoring of drinking water supply networks is critically in demand to rapidly detect the accidental or deliberate contamination of drinking water. At present, miniaturized water quality monitoring sensors developed in the laboratories are usually tested under ambient pressure and steady-state flow conditions; however, in Water Distribution Systems (WDS), both the pressure and the flowrate fluctuate. In this paper, an interface is designed and fabricated using additive manufacturing or 3D printing technology—material extrusion (Trade Name: fused deposition modeling, FDM) and material jetting—to provide a conduit for miniaturized sensors for continuous online water quality monitoring. The interface is designed to meet two main criteria: low pressure at the inlet of the sensors and a low flowrate to minimize the water bled (i.e., leakage), despite varying pressure from WDS. To meet the above criteria, a two-dimensional computational fluid dynamics model was used to optimize the geometry of the channel. The 3D printed interface, with the embedded miniaturized pH and conductivity sensors, was then tested at different temperatures and flowrates. The results show that the response of the pH sensor is independent of the flowrate and temperature. As for the conductivity sensor, the flowrate and temperature affect only the readings at a very low conductivity (4 µS/cm) and high flowrates (30 mL/min), and a very high conductivity (460 µS/cm), respectively.