Stability For Applications Research Articles

Selenium Vacancies and Synergistic Effect of Near- and Far-Field-Enabled Ultrasensitive Surface-Enhanced Raman-Scattering-Active Substrates for Malaria Detection.

Defect engineering with the active control of defect states brings remarkable enhancement on surface-enhanced Raman scattering (SERS) by magnifying semiconductor-molecule interaction. Such light-trapping architectures can increase the light path length, which promotes photon-analytes interactions and further improves the SERS sensitivity. However, by far the reported semiconductor SERS-active substrates based on these strategies are often nonuniform and commonly in the form of isolated laminates or random clusters, which limit their reliability and stability for practical applications. Herein, we develop self-grown single-crystalline "V-shape" SnSe2-x (SnSe1.5, SnSe1.75, SnSe2) nanoflake arrays (SnSe2-x NFAs) with controlled selenium vacancies over large-area (10 cm × 10 cm) for ultrahigh-sensitivity SERS. First-principles density functional theory (DFT) is used to calculate the band gap and the electronic density of states (DOS). Based on the Herzberg-Teller theory regarding the vibronic coupling, the results of theoretical calculation reveal that the downshift of band edge and high DOS of SnSe1.75 can effectively enhance the vibronic coupling within the SnSe1.75-R6G system, which in turn enhances the photoinduced charge transfer resonance and contributes to the SERS activity with a remarkable enhancement factor of 1.68 × 107. Furthermore, we propose and demonstrate ultrasensitive (10-15 M for R6G), uniform, and reliable SERS substrates by forming SnSe1.75 NFAs/Au heterostructures via a facile Au evaporation process. We attribute the superior performance of our SnSe1.75 NFAs/Au heterostructures to the following reasons: (1) selenium vacancies and (2) synergistic effect of the near and far fields. In addition, we successfully build a detection platform to achieve rapid (∼15 min for the whole process), antibody-free, in situ, and reliable early malaria detection (100% detection rate for 10 samples with 160 points) in whole blood, and molecular hemozoin (<100/mL) can be detected. Our approach not only provides an efficient technique to obtain large-area, uniform, and reliable SERS-active substrates but also offers a substantial impact on addressing practical issues in many application scenarios such as the detection of insect-borne infectious diseases.

Contribution of Polymers to Electronic Memory Devices and Applications.

Electronic memory devices, such as memristors, charge trap memory, and floating-gate memory, have been developed over the last decade. The use of polymers in electronic memory devices enables new opportunities, including easy-to-fabricate processes, mechanical flexibility, and neuromorphic applications. This review revisits recent efforts on polymer-based electronic memory developments. The versatile contributions of polymers for emerging memory devices are classified, providing a timely overview of such unconventional functionalities with a strong emphasis on the merits of polymer utilization. Furthermore, this review discusses the opportunities and challenges of polymer-based memory devices with respect to their device performance and stability for practical applications.

Organic-Inorganic Perovskite Films and Efficient Planar Heterojunction Solar Cells by Magnetron Sputtering.

Organic–inorganic halide perovskites have been widely used in photovoltaic technologies. Despite tremendous progress in their efficiency and stability, perovskite solar cells (PSCs) are still facing the challenges of upscaling and stability for practical applications. As a mature film preparation technology, magnetron sputtering has been widely used to prepare metals, metallic oxides, and some semiconductor films, which has great application potential in the fabrication of PSCs. Here, a unique technology where high‐quality perovskite films are prepared via magnetron sputtering for controllable composition, solvent‐free, large‐area, and massive production, is presented. This strategy transforms the perovskite materials from powder to thin films by magnetron sputtering and post‐treatment (vapor‐assisted treatment with methanaminium iodide gas and methylamine gas treatment), which is greatly favorable to manufacture tandem solar cells. The power conversion efficiency (PCE) of PSCs with perovskite films fabricated by magnetron sputtering is 6.14%. After optimization, high‐performance perovskite films with excellent electronic properties are obtained and stable PSCs with excellent reproducibility are realized, showing a PCE of up to 15.22%. The entirely novel synthetic approach opens up a new and promising way to achieve high‐throughput magnetron sputtering for large‐area production in commercial applications of planar heterojunction and tandem PSCs.

Influence of Co doping on physiochemical properties of MnFe2O4/C nano compounds toward oxygen reduction reaction

Recently, several researchers have found that the manganese ferrite (MnFe2O4) nanoparticle can be a promising candidate for the oxygen reduction reaction (ORR). However, the MnFe2O4 nanoparticles still face challenges on their ORR activity and stability for practical application. In this work. The Co-doped MnFe2O4 electrocatalysts are explored to improve their intrinsic activity for the ORR in alkaline electrolytes. The MnFe2−xCoxO4/C (x = 0.25–0.75) electrocatalysts show significant improvements on the ORR performance, particularly the MnFe1.5Co0.5O4/C electrocatalyst exhibits the best ORR performance with 80 mV positive shift in half-wave potential compared to the pristine MnFe2O4. Meanwhile, the MnFe1.5Co0.5O4/C nanoparticles display a uniform spherical shape with a size of ~11–15 nm, compared to the irregular shapes of the MnFe2O4/C nanoparticles with sizes in the range of ~8-~70 nm. The Co doping has redistributed the cations between the tetrahedral and octahedral sites in the MnFe2O4 structure from the XRD, TEM, FTIR, and XPS analysis. Furthermore, the particles sizes of the doped MnFe2O4/C nanoparticles are smaller and uniform, with more oxygen vacancies. In addition, the Co doping has enriched the surface Mn3+ ions and improved the conductivity of the MnFe2O4/C nanoparticles. The above results are closely related to the enhanced ORR activity of the Co-doped MnFe2O4/C compared to the pristine of the MnFe2O4/C.

"Dual Signal-On" Split-Type Aptasensor for TNF-α: Integrating MQDs/ZIF-8@ZnO NR Arrays with MB-Liposome-Mediated Signal Amplification.

Ultrasensitive and accurate detection of biomarkers in serum is of great importance for disease diagnosis and treatment. So far, the commonly used single-mode signal suffers from certain instinct drawbacks that restrict assay performances. Herein, we report the proof-of-concept fabrication of a split-type photoelectrochemical (PEC) and electrochemical (EC) dual-modal aptasensor for ultrasensitively tracing tumor necrosis factor-α, a noteworthy biological biomarker with essential clinical importance. By smart integrating molybdenum disulfide QDs/zeolitic imidazolate framework-8@ZnO nanorod arrays with a methylene blue-liposome-mediated signal amplification strategy, "dual signal-on" detection is accomplished based on a sandwich reaction of the target with aptamer-anchored carboxyl magnetic beads and an aptamer-confined MB liposome. Linear ranges of 5 fg/mL-5 μg/mL (detection limit 1.46 fg/mL) for PEC and 10 fg/mL-0.5 μg/mL (detection limit 6.14 fg/mL) for EC are obtained, respectively. An independent signal transduction mechanism supports the accuracy improvement, and a separate biological process from a translator enables convenient fabrication, short-time consumption, wider linearity, as well as outstanding reproducibility and stability in practical application. This work presents a universal bioassay route with prospects in biomedical and related areas.

Effective removal of methylene blue using nanoscale manganese oxide rods and spheres derived from different precursors of manganese

Nanoscale manganese oxide with different morphologies were developed at room temperature using different precursor salts (potassium permanganate and manganese sulfate). The obtained nanoscale morphologies, i.e., rod and sphere-shaped were characterized using BET surface area analyzer, SEM, TEM, and XRD. The manganese oxide possessed the rod and sphere-like morphologies with different pore structures. The adsorption of methylene blue on mesoporous manganese oxide followed the pseudo-second-order kinetics and best fitted with the Freundlich adsorption isotherm model with a removal capacity of 2914 mg g−1. The effect of irradiation time on degradation efficiency was also examined, which followed the first-order kinetics with a degradation efficiency of 93.12%. Furthermore, the recycling studies revealed that the spherical manganese oxide retained over 90% of the photodegradation efficiency after three cycles of methylene blue degradation, which proves its stability for practical applications. Therefore, mesoporous manganese oxide with significant adsorption and remarkable photodegradation capability can provide a way forward to fine-tune the material's properties for effective environmental remediation.

Self-healing flexible strain sensors based on dynamically cross-linked conductive nanocomposites

Self-healing, flexible, robust and adaptable strain sensors with intelligent skin-like features are greatly promising for future wearable devices. In this work, we demonstrate a self-healing flexible strain sensor with stretchability, robust mechanical strength, and high sensing sensitivity, which can monitor human motions. The sensor is constructed by the dynamically cross-linked conductive nanocomposite based on imine and quadruple hydrogen bonds. Due to the reversible interactions, the nanocomposites exhibit excellent self-healing performances with the healing efficiency up to 95%. The interfacial compatibility between the nanofillers and polymer networks is enhanced through the supramolecular interactions. Based on piezoresistive effects, the change of resistance for the nanocomposite-based strain sensor can be obviously observed under various deformation including stretching, bending, and twisting. Meanwhile, the gauge factor of the sensor reaches 46, showing high sensing sensitivity. Benefited from the self-healing feature, the sensor can withstand mechanical damage and restore the function of detecting human motions, enabling reliability and stability in practical applications, which shows great potential for developing smart wearable devices, healthcare monitoring, and human-machine interfaces.

Improved Stability and Targeted Cytotoxicity of Epigallocatechin-3-Gallate Palmitate for Anticancer Therapy.

Although with high antioxidant activity, epigallocatechin-3-gallate (EGCG) was restricted by its poor chemical stability in practical applications. One of EGCG derivatives, EGCG palmitate, was synthesized with EGCG and palmitoyl chloride to overcome instability of EGCG. However, uncertainties still exist in chemical stability and cytotoxicity of EGCG palmitate, which are essential for further exploration in anticancer therapy. Our work aims to analyze the resistance of EGCG palmitate to oxidation and summarize its targeted inhibition efficiency on cancerous cells and normal cells. High-performance liquid chromatography analysis confirmed that EGCG palmitate remained stable in air and Dulbecco's modified eagle medium (DMEM) for a longer time than EGCG. Antioxidative and pro-oxidative effects of EGCG palmitate on treated cells are proposed through reactive oxygen species (ROS) detection, respectively. It reveals that pro-oxidants by H2O2 production can exert antiproliferative and proapoptotic effects on cancerous cells and stimulate autophagy, while an antioxidant relieves oxidative stress caused by superoxide as compared to normal cells. Consequently, targeted cytotoxicity is adopted by EGCG palmitate-treated cancerous cells. Results above manifest that EGCG palmitate possesses potential to serve as a promising prodrug in anticancer treatment.

Magnetic-Assisted Methylene Blue-Intercalated Amplified dsDNA for Polarity-Switching-Mode Photoelectrochemical Aptasensing.

Organic dyes are typically applied as photosensitizers in photoelectrochemical (PEC) cells but have not been reported in polarity-reversal-mode PEC sensors with excellent sensitivity and accuracy. Herein, an elegant and robust PEC biosensor for carcinoembryonic antigen (CEA) has been designed by photocurrent polarity switching of CdTe quantum dots (QDs), which is obtained by embedding methylene blue (MB) into amplified double-stranded DNA (dsDNA) anchored to the superparamagnetic Fe3O4@SiO2. The target-triggered Exo III-assisted cyclic amplification strategy and in situ magnetic enrichment enable the remarkable sensitivity. The extraction of target-analogue single-stranded DNA (output DNA) contributes to high selectivity resulting from the elimination of possible interferences in real samples or matrixes. Particularly, this exclusive polarity-reversal-mode PEC aptasensing can efficiently eliminate the false-positive or false-negative signals, leading to accurate measurements. Moreover, different from the probes and layer-by-layer assembled photoelectric beacons on electrodes in advance, this rational split-type approach is doomed to help the PEC biosensor with additional merits of convenient fabrication, short time consumption, wider linearity, as well as outstanding reproducibility and stability in practical applications. In light of the ability of MB acting as a kind of signal probe in typical electrochemical sensors, certainly, this ingenious design can not only be extended to a wide variety of target monitoring but also provide new ideas for the construction of high-performance electrochemical and PEC biosensors.

Confined interfacial alloying of multilayered Pd-Ni nanocatalyst for widening hydrogen detection capacity

Abstract Nanostructuring of catalysts, such as Pd, is of interest for exploiting their unique surface properties cost-effectively for various applications, especially high-dose hydrogen sensing and storage. Although various Pd modifications have been reported, they have a drawback of structural instability in applications involving high hydrogen doses. Thus, our development of a multilayered Pd-Ni nanocatalyst (PN, three Pd and two Ni layers) is proposed. Here we show the confined self-alloying of Pd and Ni at their interfaces, forming ultrathin 2D-like PdNix layers that facilitate ultrafast hydrogen detection over a wide range (20 ppm to 100 %, workable at 25–100°C) with extraordinary reversibility (> 30,000 cycles, tested at 100°C). That phenomenon of our 11-nm-thick nanocatalyst is justified through experimental measurements and simulation. Thereby, the obtained results revealed the high potency of our PN with the confined self-alloying for high-dose and wide-range hydrogen sensing applications and showed a new way to construct better catalytic nanosystems at low cost.

An efficient heterogeneous catalyst of FeCo2O4/g-C3N4 composite for catalytic peroxymonosulfate oxidation of organic pollutants under visible light

It is a long-term goal to develop catalysts with high activity and stability in practical applications. Spinel FeCo2O4 has been widely researched in heterogeneous catalysis due to its characteristics of stable structure and environmental friendliness. In this work, the composites of graphitic carbon nitride (g-C3N4) and spinel iron cobaltate (FeCo2O4) have been fabricated and used to degrade rhodamine B (RhB) by combining the photocatalytic and Fenton-like reactions. The composite with 3% FeCo2O4 (3%FeCo2O4/CN) showed the best degradation efficiency, with which about 98% RhB was degraded in 45 min. The catalytic activity of 3%FeCo2O4/CN was larger than that of FeCo2O4, g-C3N4, and their mechanical mixture. The synergetic interaction between photocatalytic and Fenton-like reactions and the effective separation of the photogenerated charges are responsible for the enhanced catalytic activity. The quenching and EPR experiments exhibit that SO4−, O2−, h+, and ΟΗ, especially SO4−, are involved in the removal of RhB. The cycle experiments confirm that the used catalyst can restore its catalytic activity after calcination at 400 °C. The work suggests that the composites show a good ability to degrade organic pollutants in wastewater.

Photocatalytically Driven Self-Cleaning and Underwater Superoleophobic Copper Mesh Modified with Hierarchical Bi2WO6@CuO Nanowires for Oil/Water Separation

Oily wastewater derived from oil spill accidents and illegal discharge of oil-related industries has brought an enormous challenge to the ecosystems and economic development. Herein, hierarchical Bi2WO6@CuO nanowire arrays (NWA) were grown on the surfaces of copper meshes by a combined process of chemical oxidation and hydrothermal deposition to introduce superwetting and self-cleaning functionality for highly efficient separation of oil/water mixtures. The resultant Bi2WO6@CuO NWA-coated copper meshes exhibited superior underwater superoleophobicity and separation ability with a water flux of around 60 kL·m–2·h–1 and oil residue in the filtrate water less than 15 ppm. Under visible-light illumination, the as-fabricated copper mesh was demonstrated to possess excellent photocatalytic oxidation ability to decompose oily contaminants to achieve self-cleaning for repeated usage. Various stability tests such as thermal resistance, salt and acid/alkali corrosion, and abrasion tests were conducted to ascertain the thermal, physiochemical, and mechanical durability and stability in practical applications. Thus, the Bi2WO6@CuO NWA-coated inorganic metal mesh is a potentially promising candidate for oily wastewater treatment owing to its high separation efficiency, visible-light-driven self-cleaning ability, and high environmental stability.

Research about a Kind of Gantry Type Single-side Drive Straight Line Motion Mechanism

The article mainly has conducted comparison to three kinds of frequently-used long-span gantry type mechanism that do straight line motion, which thereby has obtained that the gantry type single-side drive mechanism hads possessed relatively prominent advantage in the smoothness, assembly debugging, reliability and maintenance aspects of the motion and it has conducted reason analysis and structural improvement to problems existed in occasions of its application in large scale equipment, long span or heavy load with impact, which therefore haves guaranteed the need for high precision and high stability in practical application.

Endocytosis‐Enabled Construction of Silica Nanochannels Crossing Living Cell Membrane for Transmembrane Drug Transport

AbstractArtificial transmembrane channel (ATC) analogs are developed for overcoming biological membrane barriers and realizing transmembrane drug delivery, which are mostly studied within artificial lipid bilayers and thus lacked enough stability in practical applications on living cells. Here, natural endocytosis of silica‐based 1D nanomaterials (nanowires) with an ultrahigh aspect ratio is investigated. Enlightened by partially endocytosed ultralong silica nanowires, ATC that can penetrate living cell membranes for transmembrane transportation of small drug molecules is creatively constructed, resulting in enhanced drug delivery efficacy and decreased the half maximal inhibitory concentration. For the first time, an in‐depth study of the cellular uptake of 1D nanomaterials with ultrahigh aspect ratios (from 10 to 120) into living cells is carried out. Through confocal laser scanning microscopy observation, the endocytosis process of ultralong nanowires, including full uptake of short nanowires and partial uptake of longer nanowires, is clarified. Theoretical simulation is performed to give a fundamental understanding on the endocytosis mechanism of ultralong 1D silica nanowires. The simulation results demonstrate the time‐dependent internalization dynamics of the nanowires, which agrees well with our experimental results. This work not only clarifies the cellular interaction between 1D nanomaterials and living cells, but also pioneers the use of natural endocytosis of 1D nanomaterials for constructing ATC.

Preparation and characterization of a novel form-stable phase change material for thermal energy storage

A series of novel polymeric form-stable phase change materials (FSPCMs) composed of poly(trimethylolpropane trimethacrylate-stearyl methacrylate) (PTS) and stearic acid were synthesized via solvent-free bulk polymerization. Stearic acid was used as phase change component, and PTS acted as supporting material. The chemical structure, crystalline properties, phase change ability, thermal reliability, and stability were characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), polarizing optical microscopy (POM), differential scanning calorimetry (DSC), accelerated thermal cycling testing, and thermogravimetric analysis (TG), respectively. The DSC results revealed that the maximum freezing and melting latent heat can reach 143.5 and 146.7 J g−1. The POM and XRD results proved the existence of spherocrystal. Accelerating thermal test and TG demonstrated that FSPCMs had good reliability and stability in practical application. The prepared form-stable phase change materials with high enthalpy and proper phase change temperature have a promising prospect in thermal energy storage.

Stability and Dynamic Evolution of Sliding Fluid-Transporting Pipes in Three-Dimensional Sense

This paper deals with the stability and dynamic evolution of a sliding pipe conveying fluid in the three-dimensional sense. The pipe is assumed to slide out from a fixed channel so that its free end is moving at the same time, a problem often associated with instabilities in applications of aerial refueling operation. To tackle this problem, the nonlinear governing equations of motion are derived by using the Hamilton’s principle and then reduced to a set of ordinary differential equations by the Galerkin’s method. A parametric study is performed to explore the transient vibration responses of the pipe for different values of flow velocity and sliding rate. Various dynamic behaviors are detected for the pipe in sliding and conveying fluid. The results show that 3-D oscillations of the pipe occur when the flow velocity exceeds a certain value, which can be affected by the sliding rate. For various flow velocities, the evolution of the dynamic characteristics of the sliding pipe can be classified into three typical types of motion. When at low flow velocity, the pipe is mainly subjected to a single type of 3-D motion. When the flow speed increases to high values, multi-type of 3-D motion consisting of three typical types occurs on the pipe. In addition, the pipe can display planar motions, transferring from one plane to the other. The result presented herein is helpful to understand the stabilities and dynamic behaviors of sliding-pipe systems used in aerial refueling applications.

Electromagnetic loss mechanisms in antimony doped tin oxide and reduced graphene oxide multilayer films

In this paper, the antimony doped tin oxide (ATO) and reduced graphene oxide (rGO) were prepared by coprecipitation method and modified Hummers’ method, respectively. Both were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vector network analyzer (VNA). The as-prepared rGO showed typical sheets-like structure and the as-prepared ATO showed typical nano-particle shape. Then, the ATO and rGO multilayer films were designed and the microwave absorption performances were numerically evaluated using finite element methods. The results showed that synergetic effects of interfacial polarization resonance and 1/4λ elimination were stimulated in 10-layerd 1.8 mm multilayer films to give a minimal reflection loss of −45.2 dB @ 16.1 GHz, and −10 dB bandwidth of 5.4 GHz, which was enhanced more than −30 dB in ATO or rGO monophase absorbers with the same thickness. This work provides a novel technical route to realize high-performance microwave absorbers in terms of simultaneously stronger absorption, broader absorption bandwidth and smaller thickness to facilitate higher flexibility and stability for practical applications.

Label-Free Detection of Transferrin Receptor by a Designed Ligand-Protein Sensor.

Advanced detection of biomarkers in biofluids plays an important role in disease diagnosis and prognosis. Current techniques with pre-labelling suffer from high cost and complicated operation, etc. Herein, we designed a label-free electrochemical biosensor for rapid detection of transferrin receptor with desirable linear range, sensitivity, specificity, reproducibility, and stability for practical applications.

Ternary Polymer Solar Cells Facilitating Improved Efficiency and Stability.

The use of a ternary active layer offers a promising approach to enhance the power conversion efficiency (PCE) of polymer solar cells (PSCs) via simply incorporating a third component. Here, a ternary PSC with improved efficiency and stability facilitated by a new small molecule IBC-F is demonstrated. Even though the PBDB-T:IBC-F-based device gives an extremely low PCE of only 0.21%, a remarkable PCE of 15.06% can be realized in the ternary device based on PBDB-T:IE4F-S:IBC-F with 20% IBC-F, which is ≈10% greater than that (PCE = 13.70%) of the control binary device based on PBDB-T:IE4F-S. The improvement in the device performance of the ternary PSC is mainly attributed to the enhancement of fill factor, which is due to the improved charge dissociation and extraction, suppressed bimolecular and trap-assisted recombination, longer charge-carrier lifetime, and enhanced intermolecular interactions for preferential face-on orientation. Additionally, the ternary device with 20% IBC-F shows better thermal and photoinduced stability over the control binary device. This work provides a new angle to develop the third components for building ternary PSCs with enhanced photovoltaic performance and stability for practical applications.

Yttrium-doped LiMn2O4 spheres with long cycle life as Lithium-Ion Battery Cathode

Lithium manganese oxide (LiMn2O4) is one of the most promising material as lithium-ion battery cathodes owing to its significant advantages such as nontoxicity and low cost at present. However, LiMn2O4 exhibits insufficient cycling stability in practical application, which is an urgent problem to be figured out. In order to overcome this shortcoming, a facile method is presented which synthesized a yttrium-doped spherical LiMn2O4 whose diameter is about 5–6 μm using cubic MnCO3 precursors. The doped LiMn2O4 samples were investigated by XRD and SEM, which indicated that the spherical LiYxMn2−xO4 is a porous structure composed of LiYxMn2−xO4 nanoparticles with an average size of about 60–80 nm. The LiYxMn2−xO4 shows an excellent cycling performance when x = 0.01. At the current density of 1C (1C = 140 mAh g−1), LiYxMn2−xO4 shows a discharge specific capacity of 120 mAh g−1 at 1C with a specific capacity retention of 96% after 650 cycles.