Search

• Introduction of 2D Tungsten Diselenide (WSe 2) monolayer for gas sensing. • Achieve fast response time of 18 s and recovery time of 38 s for 100 ppb of NO 2. • Selective sensing towards NO 2 within a wide range of concentrations from 0.1 to 5 ppm. • The sensor exhibits reliable long-term stability, reproducibility and reversibility. Two-dimensional (2D) transition metal dichalcogenides (TMDs) are promising for gas sensors owing to their large surface-to-volume ratios, but the long recovery times stemming from the slow molecular desorption have been an important limitation. In this work, we report on a sensor for nitrogen dioxide (NO 2) made with a diselenide (WSe 2) monolayer synthesized via chemical vapor deposition, which functions within a range of concentrations from 100 ppb to 5 ppm and at various temperatures, including room temperature. When operated at an optimized temperature of 250 °C, the WSe 2 sensor exhibited the fast recovery, with the response (τ res) and recovery (τ rec) times of 18 s and 38 s, respectively, when exposed to 100 ppb NO 2. The sensor also features high selectivity toward NO 2 in the presence of other target gases, in addition to reversibility and long-term stability within 60 days. The overall characteristics of the WSe 2 sensor make it suitable to monitor indoor/outdoor environments, mainly if further optimization is made with sensor design based on a model for the sensing mechanism we present in this paper. [ABSTRACT FROM AUTHOR]

• A bionic manipulator was fabricated by laser processing of a NiTi alloy. • The phase transformation behaviour depend on the laser processing parameters. • The electrical-thermo-mechanical behavior is based on alloy shape memory effect. • The bionic manipulator can be helpful for patients with hand paralysis. The thermo-mechanical properties of NiTi shape memory alloys (SMAs) have sparked significant research efforts seeking to exploit their bionic capabilities. Currently, the performance capabilities of NiTi-based devices have been inhibited by the retention of only one thermo-mechanical response in the as-received material, namely the shape memory effect (SME) or superelasticity (SE), which mainly depend on the transformation temperatures of the base material. In this work, a novel monolithic bionic manipulator was developed using a NiTi SMA by laser processing, which included both the shape memory and superelastic effects in a single Ni-rich monolithic structure. The device actuation and bending were achieved by resistive heating, which activates the SME of different laser processed regions. Each laser processed region has unique phase transformation onset temperatures and thermo-mechanical recovery characteristics thus providing distinct actuation characteristics. Additionally, the functional fatigue of the part was determined for rehabilitation training of patients including the fingers pairing and grabbing modes. [ABSTRACT FROM AUTHOR]

The traditional interacting multiple model Kalman filtering algorithm (IMM-KF) can deal with the maneuvering target problem under Gaussian noise by soft switching among possible motion models. In practice, its performance is likely to degrade when handling non-Gaussian noise. We introduce the Gaussian mixture model (GMM) into the IMM-KF, and the GMM is utilized to model the non-Gaussian measurement noise as a mixture of multiple Gaussian probability densities with a certain probability. Then, a GIMM framework is proposed that enables accurate switching and fusion among multiple possible motion and noise models. And combined with Kalman filtering (KF), a GIMM-KF algorithm is proposed that enables accurate state estimation of maneuvering targets under non-Gaussian noise conditions. Subsequently, the provided simulations and experiments validate that the GIMM-KF algorithm outperforms existing methods in terms of accuracy, stability and robustness., Competing Interests: Declaration of competing interest This study was founded by the National Natural Science Foundation of China with Grant 51975107 and Sichuan Science and Technology Major Project No. 2022ZDZX0039, No.2019ZDZX0020, and Sichuan Science and Technology Program No. 2022YFG0343., (Copyright © 2024 International Society of Automation. Published by Elsevier Ltd. All rights reserved.)

Introduction. Peri-implantitis is a plaque-associated disease that leads to implant loss and arises from bacterial biofilms on the surface of the implant. Smoking is a risk factor for peri-implantitis and impedes treatment effectiveness. Additionally, aryl hydrocarbon receptor (AHR), IL-6, and IL-22 levels are related to peri-implantitis. Aim. We aimed to investigate the effects of nicotine on inflammatory response, bacterial growth and biofilm formation. Hypothesis/Gap Statement. We hypothesized that nicotine promoted pathogenic bacterial growth and biofilm formation, thereby aggravating inflammation. Methodology. The expression of AHR, IL-6 and IL-22 was measured in peri-implant sulci fluid using quantitative PCR and Western blot analyses. The cementum was incubated with bacterial suspension including Porphyromonas gingivalis , Streptococcus sanguinis and Fusobacterium nucleatum and treated with 100, 200, 250 and 300 µg ml -1 nicotine, and then, the absorbance and number of colony-forming units were detected. Biofilm formation was evaluated using the tissue culture plate method and safranin O staining. Carbohydrates and proteins were measured by the phenol-sulfuric acid method and the bicinchoninic acid method, respectively. Results. The results indicated that smoking increased the levels of AHR, IL-6 and IL-22. Functionally, nicotine promoted the growth of P. gingivalis , S. sanguinis and F. nucleatum . Additionally, it promoted the biofilm formation of these bacteria and increased the contents of carbohydrates and proteins. Conclusion. Nicotine promoted bacterial growth and biofilm build-up, suggesting that smoking may aggravate the progression of peri-implantitis.

We have developed a finite element model to simulate the penetration of nanoneedles into the cellular nucleus. It is found that the nuclear lamina, the primary supporting structure of the nuclear membrane, plays a crucial role in maintaining the integrity of the nuclear envelope and enhancing stress concentration in the nuclear membrane. Notably, nuclear lamina A exhibits a more pronounced effect compared to nuclear lamina B. Subsequently, we further conducted experiments by controlling the time of osteopontin (OPN) treatment to modify the nuclear lamina density, and the results showed that an increase in nuclear lamina density enhances the probability of nanoneedle penetration into the nuclear membrane. Through employing both simulation and experimental techniques, we have gathered compelling evidence indicating that an augmented density of nuclear lamina A can enhance the penetration of nanoneedles into the nuclear membrane., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Error entropy is a well-known learning criterion in information theoretic learning (ITL), and it has already been applied to a wide range of fields. However, the shape of error entropy cannot be changed freely since its kernel function is the Gaussian kernel function, which causes the error entropy-based algorithm to handle only some specific kinds of noises. Benefiting from the property that the generalized Gaussian kernel function is free to adjust its shape, a novel Kalman-type filter algorithm based on the generalized minimum error entropy (GMEEKF) criterion is derived. Moreover, the mean error behavior, mean square error behavior, and computational complexity of the GMEEKF algorithm are analyzed. Finally, several simulations and experiments are performed to demonstrate the performance of the GMEEKF algorithm in comparison with the existing Kalman-type filter algorithms., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 ISA. Published by Elsevier Ltd. All rights reserved.)

Graphene demonstrates high potential as an atomically thin solid lubricant for sliding interfaces in industry. However, graphene as a coating material does not always exhibit strong adhesion to any substrates. When the adhesion of graphene to its substrate weakens, it remains unknown whether relative sliding at the interface exists and how the tribological properties of the graphene coating changes. In this work, we first designed a method to weaken the adhesion between graphene and its SiO 2 substrate. Then the graphene with weakened adhesion to its substrate was rubbed using an AFM tip, where we found a novel phenomenon: the monolayer graphene not only no longer protected the SiO 2 substrate from deformation and damage, but also prompted the formation of hillock-like structures with heights of approximately tens of nanometers. Moreover, the surface of the hillock-like structure exhibited very low adhesion and a continuously decreasing friction force versus sliding time. Comparing the hillock-like structure on the bare SiO 2 surface and the proposed force model, we demonstrated that the emergence of the hillock-like structure (with very low adhesion and continuously decreasing friction) was ascribed to the relative sliding at the graphene/substrate interface caused by the mechanical shear of the AFM tip. Our findings reveal a potential failure of the graphene coating when the adhesion strength between graphene and its substrate is damaged or weakened and provide a possibility for in situ fabrication of a low friction and adhesion micro/nanostructure on a SiO 2 /graphene surface., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

In recent years, researchers are paying the increasing attention to the development of portable microfluidic diagnostic devices including microfluidic flow cytometry for the point-of-care testing. Microfluidic flow cytometry, where microfluidics and flow cytometry work together to realize novel functionalities on the microchip, provides a powerful tool for measuring the multiple characteristics of biological samples. The development of a portable, low-cost, and compact flow cytometer can benefit the health care in underserved areas such as Africa or Asia. In this article, we review recent advancements of microfluidics including sample pumping, focusing and sorting, novel detection approaches, and data analysis in the field of flow cytometry. The challenge of microfluidic flow cytometry is also examined briefly., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: To observe the effect of intrathecal injection of nuclear factor-κB (NF-κB) inhibitor of pyrrolidine dithiocarbamate (PDTC) on pain sensitivity thresholds and the expression of spinal cord CX3C chemokine receptor 1 (CX3CR1) in monoarthritis (MA) model in rats., Methods: Forty-eight Sprague-Dawley rats were randomly divided into 4 groups (12 each) after successful intrathecal catheterization: (1) sham operation with physiological saline group (the sham group); (2) MA with normal saline group (the MA group); (3) 10 μL 100 μmol/L PDTC before MA (the PDTC pre-treatment group); (4)MA before 10 μL 100 μmol/L PDTC (the PDTC post-treatment group). Normal saline or PDTC was injected 5 d after the intrathecal catheterization. Pain sensitivity thresholds were measured in the 4 groups before and after the intrathecal injection at different time points. Rat monoarthritis model was subsequently built by injecting complete Freund's adjuvant (CFA) into the left ankle joint of the rats. On day 3 after the intrathecal injection, expression of microglia in the L₅ spinal cord segment was observed by immunohistochemical method, and the lumbar segments L₄-L₅ of spinal cord were taken to perform RT-PCR to examine the expression of NF-κB mRNA and CX3CR1 mRNA., Results: Compared with the MA group, the pain sensitivity thresholds in the sham group, the PDTC pre-treatment group and the PDTC post-treatment group at each time point after the intrathecal injection increased significantly (P<0.05), while microglia in the L₅ spinal cord segment decreased significantly (P<0.05) and expression of CX3CR1 mRNA and NF-κB mRNA in the lumbar segments L₄-L₅ of spinal cord decreased significantly (P<0.05)., Conclusion: The hyperalgesic effect of the CFA-induced model of monoarthritis can be relieved by intrathecal injection of NF-κB inhibitor PDTC. Its mechanism is possibly related to NF-κB signal pathway which is involved in the formation of inflammatory pain through regulating CX3CR1 expression.

Understanding the mechanical properties of nanowires made of semiconducting materials is central to their application in nano devices. This work presents an experimental and computational approach to unambiguously quantify size effects on the Young's modulus, E, of ZnO nanowires and interpret the origin of the scaling. A micromechanical system (MEMS) based nanoscale material testing system is used in situ a transmission electron microscope to measure the Young's modulus of [0001] oriented ZnO nanowires as a function of wire diameter. It is found that E increases from approximately 140 to 160 GPa as the nanowire diameter decreases from 80 to 20 nm. For larger wires, a Young's modulus of approximately 140 GPa, consistent with the modulus of bulk ZnO, is observed. Molecular dynamics simulations are carried out to model ZnO nanowires of diameters up to 20 nm. The computational results demonstrate similar size dependence, complementing the experimental findings, and reveal that the observed size effect is an outcome of surface reconstruction together with long-range ionic interactions.