An intelligent transportation system (ITS) plays an important role in public transport management, security and other issues. Traffic flow detection is an important part of the ITS. Based on the ...real-time acquisition of urban road traffic flow information, an ITS provides intelligent guidance for relieving traffic jams and reducing environmental pollution. The traffic flow detection in an ITS usually adopts the cloud computing mode. The edge of the network will transmit all the captured video to the cloud computing center. However, the increasing traffic monitoring has brought great challenges to the storage, communication and processing of traditional transportation systems based on cloud computing. To address this issue, a traffic flow detection scheme based on deep learning on the edge node is proposed in this article. First, we propose a vehicle detection algorithm based on the YOLOv3 (You Only Look Once) model trained with a great volume of traffic data. We pruned the model to ensure its efficiency on the edge equipment. After that, the DeepSORT (Deep Simple Online and Realtime Tracking) algorithm is optimized by retraining the feature extractor for multiobject vehicle tracking. Then, we propose a real-time vehicle tracking counter for vehicles that combines the vehicle detection and vehicle tracking algorithms to realize the detection of traffic flow. Finally, the vehicle detection network and multiple-object tracking network are migrated and deployed on the edge device Jetson TX2 platform, and we verify the correctness and efficiency of our framework. The test results indicate that our model can efficiently detect the traffic flow with an average processing speed of 37.9 FPS (frames per second) and an average accuracy of 92.0% on the edge device.
The modern power system is becoming more complicated due to the ever increasing penetration of power electronics, which is referred to as a power-electronics-dominated system (PEDS). In this case, ...the analysis, control, and operation of the entire power system should tone with the energy-paradigm transition pace, where the challenges should be properly tackled. After the brief introduction of grid-connected converters, this article explores stability challenges of PEDSs, especially on the low inertia issue and multitimescale characteristics, as well as the dynamics when connected to weak grids. The low inertia issue is considered as one of great challenges that power electronics introduce to the conventional power grid. Accordingly, the stability issues of PEDSs are discussed. The exploration reveals that the multitimescale coupling among various control loops and the mutual effects of multiple converters demand much more attention than ever before. The coordinated control of converters for the global stability of PEDSs is also summarized, part of which offers the possibility to solve the inertia problem. This article serves as an inspiration on potential solutions to these issues. In order to provide a more intuitive impression of the inertia problem in PEDSs, a case study is exemplified to highlight the analysis and discussion.
Multifunctional nanocomposites have the potential to integrate sensing, diagnostic, and therapeutic functions into a single nanostructure. Herein, we synthesize Fe3O4@polydopamine core–shell ...nanocomposites (Fe3O4@PDA NCs) through an in situ self-polymerization method. Dopamine, a melanin-like mimic of mussel adhesive proteins, can self-polymerize to form surface-adherent polydopamine (PDA) films onto a wide range of materials including Fe3O4 nanoparticles used here. In such nanocomposites, PDA provides a number of advantages, such as near-infrared absorption, high fluorescence quenching efficiency, and a surface for further functionalization with biomolecules. We demonstrate the ability of the Fe3O4@PDA NCs to act as theranostic agents for intracellular mRNA detection and multimodal imaging-guided photothermal therapy. This work would stimulate interest in the use of PDA as a useful material to construct multifunctional nanocomposites for biomedical applications.
Battery-based energy storage system is a key component to achieve low carbon industrial and social economy, where battery health status plays a vital role in determining the safety and reliability of ...energy-transportation nexus. This article proposes a transferred recurrent neural network (RNN)-based framework to achieve efficient calendar capacity prognostics under both witnessed and unwitnessed storage conditions. Specifically, this transferred RNN framework contains a base model part and a transfer model part. The base model is first trained by using the easily collected and time-saving accelerated ageing dataset from high temperature and state-of-charge (SOC) cases. Then the transfer part is tuned by using only a small portion of starting capacity data from unwitnessed condition of interest. The developed framework is evaluated under a well-rounded ageing dataset with three different storage SOCs (20%, 50%, and 90%) and temperatures (10 °C, 25 °C, and 45 °C). Experimental results demonstrate that the derived transferred RNN framework is capable of providing satisfactory calendar capacity health prognostics under different storage cases. A model structure with the impact factor terms of SOC and temperature outperforms other counterparts especially for the unwitnessed conditions. The proposed framework could assist engineers to significantly reduce battery ageing experiment burden and is also promising to capture future capacity information for battery health and life-cycle cost analysis of energy-transportation applications.
Colorectal cancer (CRC) is one of the most common digestive tract tumors worldwide. Catalpol exerts inhibitory effects on the progression of several cancer types by regulating microRNAs (miRs). ...However, the precise role and carcinostatic mechanism of catalpol on CRC cells are poorly understood which limits the application of catalpol treatment. In the present study, miR‑34a and sirtuin 1 (SIRT1) expression levels were detected in CRC tissues and CRC cell lines by RT‑qPCR. Computational software analysis, luciferase assays and western blotting were used to demonstrate the downstream target of miR‑34a in CRC cells. Effects of catalpol on cell viability, apoptosis, autophagic flux and the miR‑34a/SIRT1 axis in the CRC cells were assessed by CCK‑8 assay, flow cytometry, electron microscopy and western blotting, respectively. Whether the miR‑34a/SIRT1 axis participated in catalpol‑mediated autophagy and apoptosis was investigated. The effects of catalpol on the miR‑34a/SIRT1 axis and malignant behavior were evaluated in a rat model of azoxymethane (AOM)‑induced CRC. It was revealed that miR‑34a expression levels were significantly decreased while SIRT1 was overexpressed in most of the CRC tissues and all the CRC cell lines. Clinically, a low level of miR‑34a was correlated with poor clinicopathological characteristics in CRC patients. Catalpol reduced cell viability, suppressed autophagy, promoted apoptosis, and regulated the expression of SIRT1 by inducing miR‑34a in vitro and in vivo. The autophagy‑inhibiting effect of catalpol may be a mechanism to promote apoptosis of CRC cells. miR‑34a mimic transfection resulted in autophagy‑suppressive activity similar to that of catalpol, while the miR‑34a inhibitor attenuated the antiautophagic effects of catalpol. In conclusion, miR‑34a is involved in regulating catalpol‑mediated autophagy and malignant behavior by directly inhibiting SIRT1 in CRC.
Frequency security is one of the challenges for the power grid penetrated by renewable energy systems (RESs). Virtual inertia provision from the RESs is considered to be efficient support for ...frequency security enhancement. How to estimate the frequency nadir rapidly and accurately is crucial for the online inertia allocation for the RESs. This paper develops a generic average system frequency (G-ASF) model for the power grid to estimate the frequency nadir at first. The low-order generic model of the speed governing system of the SG is proposed to enhance the accuracy and flexibility of the G-ASF model. Then, based on the G-ASF model, an online inertia allocation strategy for the grid-connected RESs under frequency nadir constraint is proposed. With the pre-identified generic models of the speed governing systems, the G-ASF model of the entire power grid is periodically updated according to the grid operation state. Next to the model updating, the critical inertia of the power grid is periodically calculated under the pre-defined contingencies for frequency security verification. Then, the virtual inertia provision tasks are determined and allocated to the RESs periodically, and the grid frequency security is effectively ensured. The simulation results validate the proposed model and strategy.
Background
Exosomes are newly recognized natural nanocarrier and intercellular messenger that emerge as important mediators of signal transmission. Exosomes have been reported to modulate the ...inflammatory response of a number of diseases. This study investigated the effects of circulating exosomes from oral lichen planus (OLP) on T cells.
Methods
Plasma‐derived exosomes were purified from both OLP patients and control groups. T cells were observed under a confocal laser scanning microscope after co‐cultivation with PKH67 labeled exosomes for 12, 24, and 48 hours. The effects of exosomes exposure on T cells were analyzed with several functional assays, investigating proliferation, apoptosis, and migration. Production of interleukin (IL)‐2, ‐4, ‐10, and interferon (IFN)‐γ was measured via enzyme‐linked immunosorbent assay.
Results
PKH67‐labeled exosomes were taken up by T cells in a time‐ and dose‐dependent manner. Several biological functions of T cells were promoted. In particular, the circulating erosive OLP exosomes significantly enhanced T‐cell proliferation and attenuated the apoptosis. The migration capacity of T cells increased remarkably in response to erosive OLP exosome treatment. In addition, the ratio of IFN‐γ/IL‐4 was significantly elevated in OLP patients.
Conclusions
Our findings indicate that the circulating OLP exosomes are involved in the biological functions of T cells, potentially promoting the OLP progression by regulating the T‐cell–mediated inflammatory response.
Grid frequency support, e.g., by the virtual inertia control (VIC), of photovoltaic (PV) systems, is more demanded than ever before. To achieve the full-range frequency support (i.e., to tackle the ...under- or overfrequency issues), the power reserve is necessary for PV systems. Accordingly, a power reserve control (PRC) method based on the maximum power point tracking (MPPT) is adopted in this article, referring to as MPPT-PRC. It measures the real-time maximum available power (MAP) periodically, being independent of physical sensors and burdensome computation. However, the MAP measurement loop inevitably couples with the power reserve loop, which makes the realization of the VIC challenging. Aiming at this issue, an event-triggering strategy is elaborately designed to switch the PV system in-between different operating modes. The strategy is realized by a set of control signals. They are responsible for the detection of frequency incidents, the activation of MPPT, the measurement of MAP, respectively. Consequently, the VIC can be achieved based on the MPPT-PRC without any conflicts or instability. Experimental tests are performed on StarSim real-time hardware-in-the-loop system to validate the proposed MPPT-PRC-based VIC, as well as the coordination of the control loops.
In extremely cold climates, lithium-ion batteries suffer from a free-fall drop in the available capacity and useful life, which must be preheated before normal operations. The alternating-current ...(AC) heater has been developed by using buck-boost converters to achieve fast and consistent heating. However, it is difficult to preheat cold batteries rapidly without damaging them. Therfore, an intelligent preheating approach based on high-gain control (HGC) is developed to adaptively adjust the AC heating current based on heating rate and battery temperature. Smaller AC heating currents are generated at lower battery temperatures and larger AC heating currents are generated at higher temperatures. In this way, the batteries can be preheated to a high temperature within a specified time without damaging battery health. Experimental results illustrate that the proposed approach has strong robustness and high reliability, which can effectively preheat low-temperature batteries under different conditions without the need of complicated battery model.
To evaluate the effect of stent implantation for vertebrobasilar artery stenosis，by using 3D arterial spin labeling (3D ASL) technique.
A retrospective analysis was conducted on the clinical and 3D ...ASL data of 48 patients who underwent vertebral-basilar artery stenting. Post-labeling delay times (PLD) of 1.5 s and 2.5 s were chosen, and the average regional cerebral blood flow (rCBF) values were measured in nine brain regions of the posterior circulation: bilateral thalamus, bilateral occipital lobes, bilateral cerebellar hemispheres, midbrain, pons, and medulla. The 48 patients were divided into two groups based on the presence or absence of acute ischemic stroke in the posterior cerebral circulation region detected by diffusion-weighted imaging (DWI). The preoperative and postoperative rCBF results were statistically analyzed.
In the infarct group, there were significant increases in rCBF values of all nine brain regions at both PLD = 1.5 s and 2.5 s postoperatively compared to preoperatively. At PLD = 1.5 s, statistically significant differences in rCBF values between the preoperative and postoperative periods were found in the right thalamus, left cerebellum, midbrain, and pons regions (P < 0.05). At PLD = 2.5 s, statistically significant differences in rCBF values between the preoperative and postoperative periods were observed in the left occipital lobe, right cerebellum, midbrain, and pons regions (P < 0.05). When analyzing the rCBF values of the brain regions with recent infarcts in the infarct group, there was a significant increase in postoperative rCBF values compared to preoperative values (P < 0.05). After excluding the data from brain regions with recent infarcts, the CBF values in the remaining brain regions were also increased postoperatively, and some brain regions showed statistically significant differences in rCBF values between the preoperative and postoperative periods (P < 0.05). In the non-infarct group, there were no statistically significant differences in the preoperative and postoperative rCBF values in all brain regions at both PLD = 1.5 s and 2.5 s (P > 0.05).
The application of 3D ASL technology shows significant value in assessing the surgical efficacy of vertebral-basilar artery stenting, especially in patients with acute posterior circulation infarction.
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