We consider the influence of an electric field applied normal to the electric double layer at a chemically reactive surface. Our goal is to elucidate how surface chemistry affects the potential for ...field-effect control over micro- and nanofluidic systems, which we call electrofluidic gating. The charging of a metal-oxide−electrolyte (MOE) capacitor is first modeled analytically. We apply the Poisson−Boltzmann description of the double layer and impose chemical equilibrium between the ionizable surface groups and the solution at the solid−liquid interface. The chemically reactive surface is predicted to behave as a buffer, regulating the charge in the double layer by either protonating or deprotonating in response to the applied field. We present the dependence of the charge density and the electrochemical potential of the double layer on the applied field, the density, and the dissociation constants of ionizable surface groups and the ionic strength and the pH of the electrolyte. We simulate the responses of SiO2 and Al2O3, two widely used oxide insulators with different surface chemistries. We also consider the limits to electrofluidic gating imposed by the nonlinear behavior of the double layer and the dielectric strength of oxide materials, which were measured for SiO2 and Al2O3 films in MOE configurations. Our results clarify the response of chemically reactive surfaces to applied fields, which is crucial to understanding electrofluidic effects in real devices.
Chronic unpredictable mild stress (CUMS) can not only lead to depression-like behavior but also change the composition of the gut microbiome. Regulating the gut microbiome can have an antidepressant ...effect, but the mechanism by which it improves depressive symptoms is not clear. Short-chain fatty acids (SCFAs) are small molecular compounds produced by the fermentation of non-digestible carbohydrates. SFCAs are ubiquitous in intestinal endocrine and immune cells, making them important mediators of gut microbiome-regulated body functions. The balance between the pro- and anti-inflammatory microglia plays an important role in the occurrence and treatment of depression caused by chronic stress. Non-absorbable antibiotic rifaximin can regulate the structure of the gut microbiome. We hypothesized that rifaximin protects against stress-induced inflammation and depression-like behaviors by regulating the abundance of fecal microbial metabolites and the microglial functions.
We administered 150 mg/kg rifaximin intragastrically to rats exposed to CUMS for 4 weeks and investigated the composition of the fecal microbiome, the content of short-chain fatty acids in the serum and brain, the functional profiles of microglia and hippocampal neurogenesis.
Our results show that rifaximin ameliorated depressive-like behavior induced by CUMS, as reflected by sucrose preference, the open field test and the Morris water maze. Rifaximin increased the relative abundance of Ruminococcaceae and Lachnospiraceae, which were significantly positively correlated with the high level of butyrate in the brain. Rifaximin increased the content of anti-inflammatory factors released by microglia, and prevented the neurogenic abnormalities caused by CUMS.
These results suggest that rifaximin can regulate the inflammatory function of microglia and play a protective role in pubertal neurodevelopment during CUMS by regulating the gut microbiome and short-chain fatty acids.
The micro-mechanical properties of hardened cement paste can be obtained by nanoindentation. Phases at different locations can generally be determined by using the Gaussian mixture model (GMM) method ...and the K-means clustering (KM) method. However, there are differences between analysis methods. In this study, pore structure and porosity of hardened cement paste aged three, seven, and 28 days were obtained by mercury intrusion porosimetry (MIP), and their micro-mechanical properties were obtained by the nanoindentation method. A new method, GMM-MIP and KM-MIP, was proposed to determine the phase of hardened cement paste based on the pore structure and nanoindentation results. The results show that GMM-MIP and KM-MIP methods are more reasonable than GMM and KM methods in determining the phase of hardened cement paste. GMM-MIP can be used to obtain reasonable phase distribution. If the micro-mechanical properties of each phase in hardened cement paste do not satisfy the normal distribution, the GMM method has significant defects.
Nanopores with one or two embedded nanoelectrodes can be fabricated by high resolution, milling-based methods. We first demonstrate how a focused ion beam, whose sputtering mechanism is well ...understood, can create a nanopore containing an annular electrode of an arbitrary metal, and with a regular perimeter. The inner surface of the nanopore can be insulated, and its diameter can be reduced with nanometer precision, by conformally coating a dielectric material by atomic layer deposition. We then investigate the mechanism of pore formation using a transmission electron microscope (TEM) through studies of the milling rate, and its dependence on the flux of electrons and on the atomic number of different target metals. Sputtering from the surface is identified as the dominant mechanism. Accordingly, light element conductors should be chosen to enhance the rate and resolution of TEM milling, which we demonstrate by articulating a nanopore with transverse carbon nanotube electrodes. Finally, we electrochemically verify that TEM milling preserves the quality of an annular gold electrode through cyclic voltammetry measurements performed at various stages of the fabrication.
The object detection task is usually affected by complex backgrounds. In this paper, a new image object detection method is proposed, which can perform multi-feature selection on multi-scale feature ...maps. By this method, a bidirectional multi-scale feature fusion network was designed to fuse semantic features and shallow features to improve the detection effects of small objects in complex backgrounds. When the shallow features are transferred to the top layer, a bottom-up path is added to reduce the number of network layers experienced by the feature fusion network, reducing the loss of shallow features. In addition, a multi-feature selection module based on the attention mechanism is used to minimize the interference of useless information in subsequent classification and regression, allowing the network to adaptively focus on appropriate information for classification or regression to improve detection accuracy. Because the traditional five-parameter regression method has severe boundary problems when predicting objects with large aspect ratios, the proposed network treats angle prediction as a classification task. The experimental results on the DOTA dataset, the self-made DOTA-GF dataset and the HRSC 2016 dataset show that, compared with several popular object detection algorithms, the proposed method has certain advantages in detection accuracy.
Objective. To investigate whether and how the working memory impairment induced by sleep deprivation (SD) could be recovered by using repetitive transcranial magnetic stimulation (rTMS), as well as ...to clarify the corresponding brain activity changes. Methods. Seventeen healthy adults received one session of 5.0 Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC) following 24 hours of SD. Resting state functional magnetic resonance imaging (fMRI) and working memory test were performed during a rested waking period, after SD and rTMS. The amplitude of low-frequency fluctuations (ALFF) was used to detect the spontaneous neural activity changes after both SD and rTMS. The relationship between ALFF and the performance of working memory was also assessed by using correlation analysis. Results. After SD, the participants exhibited lower response accuracies and longer reaction times on the working memory tests of letters and numbers. The decreased response accuracy of numbers was significantly improved after rTMS similarly to the state of the rested waking period after a normal night of sleep. ALFF values decreased from the rested waking period state to the state of SD in the brain regions involving the frontal gyrus, precuneus, angular gyrus, and parietal lobe which showed significantly increased ALFF after rTMS. Furthermore, significantly positive correlations were observed between changes of response accuracy and the changes of ALFF value of the inferior frontal gyrus and supramarginal gyrus. Conclusion. These results indicate that high-frequency rTMS applied over left DLPFC may contribute to the recovery of the impaired working memory after SD by modulating the neural activity of related brain regions.
To improve the reliability of the incremental dynamic analysis, the Monte Carlo simulation technique is introduced to fully consider the uncertainties in the characteristics of earthquakes. To match ...the computational efficiency of Monte Carlo simulation, structural seismic responses are calculated by neural networks. To consider the failure risks under 3 safety requirements imposed on the structural seismic performance by the Chinese standard, the equivalent failure probability is employed to compare the safety of 4 different design schemes composed of high-rise frame structures. The workflow of the proposed method is demonstrated by taking the 4 design schemes as examples; good agreement is found between the failure probabilities of the entire structures and their stories with their failure states. Furthermore, the safety of these schemes is compared, and some design advice is discussed.
This paper presents a neural network-based feedback control method for enhancing the control precision and tracking speed of a permanent magnet brushless motor under command control. The proposed ...method involves real-time adjustment of the PID controller parameters using electromechanical output signals, enabling adaptive feedback control based on motor output. Experimental results demonstrate that this approach enhances real-time performance and dynamic load response capability, resulting in a current waveform with excellent tracking and low distortion. Overall, this method effectively improves and enhances control effectiveness. Furthermore, the developed control method is successfully applied to the development of tangible products.
Medical interventional catheters are indispensable medical devices that are continuing to reshape current practice in many specialties of clinical applications. However, there has been rapid ...development of catheters, it remains many challenges in antibiofilm and effective drug delivering. Inspired by natural creatures, a bioinspired superwettable catheter is developed which is constructed with inverse opal photonic crystals hydrogel. The superwettability property is achieved by creating a slippery liquid‐infused porous surface (SLIPS) where the motion state of droplets changes. The expansion and contraction of the hydrogel endow the catheter with tunable structural color and drug release properties. Thus, the catheter could not only report the variation of the drug release process via SLIPS phenomenon obviously but also quantitatively give feedback on the drug release process through visually structural color variations. The multifunctional superwettable catheter shows good antibacterial performance and can be used for drug release monitoring which has excellent prospects in biomedical applications.
The bioinspired catheter could not only report the variation of the drug release process via slippery liquid‐infused porous surface phenomenon obviously but also quantitatively feedback the drug release process through visually structural color variations. And it also shows good antibacterial property which might useful for biomedical applications.
High-grade serous ovarian carcinoma (HGSOC), the most common and aggressive subtype of epithelial ovarian cancer, is characterized by TP53 mutations and genetic instability. Using miRNA profiling ...analysis, we found that miR-145, a p53 regulated miRNA, was frequently down-regulated in HGSOC. miR-145 down-regulation was further validated in a large cohort of HGSOCs by qPCR. Overexpression of miR-145 in ovarian cancer cells significantly suppressed proliferation, migration and invasion in vitro and inhibited tumor growth and metastasis in vivo. Metadherin (MTDH) was subsequently identified as a direct target of miR-145, and was found to be significantly up-regulated in HGSOC. Furthermore, overexpression of MTDH rescued the inhibitory effects of miR-145 in ovarian cancer cells. Finally, we found that high level of MTDH expression correlated with poor prognosis of HGSOC. Therefore, lack of suppression of MTDH by miR-145 when p53 is dysfunctional leads to increased tumor growth and metastasis of HGSOC. Our study established a new link between p53, miR-145 and MTDH in the regulation of tumor growth and metastasis in HGSOC.
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