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Capsule endoscopy (CE) enables noninvasive examination of the gastrointestinal (GI) tract. However, there is still no viable way to solve capsule retention (CR), which is the most worrisome complication of CE in a clinic. The CR rate did not decrease with the continuous development of the CE. Here, we proposed a novel approach that fabricated a programmable adaptive anti-retention module (PARM) with a small size and integrated it into the capsules to alleviate the retention of the capsules in the GI tract. We developed a durable, ultrawide range and highly sensitive pressure sensor, along with four different trigger logic circuits, to construct four PARMs with diverse application potentials. The miniature PARM is capable of detecting pressure and adapting to trigger vibration at a very high frequency based on the preset pressure program, or alternatively, the vibration can be controlled wirelessly according to the pressure values. Ex vivo and in vivo experiments have demonstrated that PARM can effectively relieve the blockage of capsules in the intestines and promote intestinal peristalsis. The proposed PARM is a positive exploration and attempts to alleviate the CR problem, demonstrating the significant potential for reducing the CR rate in a clinic.

Real-time detection of VOCs in the car cabin is crucial for protecting driver’s health. MOS gas sensors, with the advantages of low cost, simplicity and fast response, are widely used for gas monitoring. However, they typically exhibit broad-spectrum responsiveness to multiple gases. Despite numerous improvement strategies proposed from the perspective of MOS material modification, achieving ideal gas selectivity remains challenging. An e-nose based on gas sensor array is a promising approach for gas identification. However, the hardware circuit system and battery supply module in traditional e-nose result in large size, complex structure, and inconvenience in use. In this work, we synthesized MOS materials with different morphologies to form a microarray containing six MEMS gas sensors, and developed a novel belt-shaped wireless and battery-free flexible e-nose, where a mobile phone serves as its wireless power supply and data communication system. This design provides a flexible e-nose with excellent wearability and safety, allowing users to monitor surrounding gas conditions at any time conveniently. Subsequently, we design pattern recognition models using algorithms such as MLP, RF, XGBoost, and LGBM, in combination with ensemble learning strategies, achieving high accuracy in VOCs classification and low-error concentration prediction. This flexible e-nose holds significant application value for gas detection in car cabins and indoor environments.

Carbonyl sulfide (COS) generated from various chemical and metallurgical industry sectors has been receiving considerable attention due to its environmental impact and threat to production chains. The catalytic hydrolysis of COS has been considered an economic way for converting the unremovable COS into H2S that subsequently can be easily removed through the mature wet or dry desulfurization process. Searching for an effective catalyst with stable activity is always crucial for COS hydrolysis. In this study, alkali-free ordered mesoporous Al2O3with a larger pore size, incorporated with Ni, Cu, or Fe as an additive, and synthesized viaa one-pot approach has been investigated for the catalytic hydrolysis of COS at low temperatures. It has been demonstrated that alumina with ordered mesoporous structures exhibits significant catalytic activity over COS hydrolysis whose activity improved further when incorporated with transition metals. More importantly, the enlargement of mesopore size for all the catalysts is critical for maintaining their catalytic performance. By optimizing the pore size and the type of additive, a highly active and stable catalyst of Ni-containing mesoporous Al2O3with a large pore size has been established, which exhibits a long-term COS conversion above 95% and strong sulfur resistance. With the help of various characterization techniques, the details of the hydrolysis reaction, as well as the sulfur poisoning mechanism, have been revealed. It is envisaged that the synthesized catalyst of alkali-free ordered mesoporous Al2O3holds great application potential for the catalytic hydrolysis of COS in practical industrial applications.

A chemiresistive gas sensor based on a three-dimensional Ag-modified reduced graphene oxide (3D Ag-rGO) aerogel is reported. We improve the graphene-based sensor performance by optimization of operating temperature, chemical modification, and new design of the material geometrical structure. The self-assembly and Ag nanoparticle (NP) decoration of the Ag-rGO aerogel are realized by a facile, one-step hydrothermal method. An integrated low-power microheater fabricated on a micromachined SiO2membrane is employed to enhance the performance of the sensor with a fast response to NO2and a shortened recovery time. The 3D Ag-rGO-based sensor at a temperature of 133 °C exhibits the highest response. At the same time, the response to other gases is suppressed while the response of the Ag-rGO sensor toward ammonia at 133 °C is reduced to half of the value at room temperature, demonstrating a greatly improved selectivity toward NO2. Additionally, the sensor exhibits a remarkably fast response to 50 ppb NO2and a low limit of detection of 6.9 ppb.

A-manifolds and B-manifolds, introduced by Gray (1978), are two significant classes of Einstein-like Riemannian manifolds. A Riemannian manifold is Ricci parallel if and only if it is simultaneously an A-manifold and a B-manifold. The present paper proves that both focal submanifolds of each isoparametric hypersurface in unit spheres with g= 4 distinct principal curvatures are A-manifolds. As for the focal submanifolds with g= 6, m= 1 or 2, only one is an A-manifold, and neither is a B-manifold.

Wearable strain sensors can transfer human physical motions into digital features and connect the real world to the virtual world. However, there is still a huge challenge to prepare breathable strain sensors with good sensitivity, stretchability, softness, durability, and biocompatibility, simultaneously. Herein, we employ the soft silicone elastomer as a highly stretchable substrate and propose a new strain sensor based on the carbon nanotubes@porous soft silicone elastomer (CNTs@PSSE) by salt-template-assisted and dip-coating methods. The CNTs (conductive fillers) are firmly embedded in the PSSE. The obtained sensors exhibit excellent sensitivity up to 2845.1 and a large sensing strain range of 186%. Notably, the CNTs@PSSE sensors also possess strong robustness, which can resist ultrasonic deterioration and carry out more than 10,000 high-frequency stretch–relax cycles in the presence of an obvious notch caused by the scissor. Moreover, the excellent biocompatibility indicates that the sensors can be safely attached to human skin for precisely detecting full-range human motions and being configured on smart wireless gloves for synchronous control of the bionic hand robot.

Materials in nature feature versatile and programmable interactions to render macroscopic architectures with multiscale structural arrangements. By rationally combining metal–carboxylate and metal–organophosphate coordination interactions, Au25(MHA)18(MHA, 6-mercaptohexanoic acid) nanocluster self-assembled structural color coating films and phytic acid (PA)–metal coordination complexes are sequentially constructed on the surface of titanium implants. The Lewis acid–base coordination principle applies for these metal–organic coordination networks. The isotropic arrangement of nanoclusters with a short-range order is investigated viagrazing incidence wide-angle X-ray scattering. The integration of robust M–O (M = Ti, Zr, Hf) and labile Cu–O coordination bonds with high connectivity of Au25(MHA)18nanoclusters enables these artificial photonic structures to achieve a combination of mechanical stability and bacteriostatic activity. Moreover, the colorless and transparent PA–metal complex layer allows the viewing of the structural color and surface wettability switching to hydrophilic and makes feasible the interfacial biomineralization of hydroxyapatite. Collectively, these modular metal–organic coordination-driven assemblies are predictive and rational material design strategies with tunable hierarchy and diversity. The complete metal–organic architectures will not only help improve the physicochemical properties of the bone–implant interface with synergistic antibacterial and osseointegration activities but also can boost surface engineering of medical metal implants