258 research outputs found
Inhibiting toll-like receptor 4 signaling ameliorates pulmonary fibrosis during acute lung injury induced by lipopolysaccharide: an experimental study
<p>Abstract</p> <p>Background</p> <p>Toll-like receptor 4 (TLR4) is essential in lipopolysaccharide (LPS)-induced fibroblast activation and collagen secretion in vitro. However, its effects on the process of lung fibroblast activation and fibrosis initiation during LPS induced acute lung injury (ALI) remain unknown. The goal of the present study was to determine the effect of inhibiting TLR4 on LPS-induced ALI and fibrosis in vivo.</p> <p>Methods</p> <p>The ALI model was established by intraperitoneal injection of LPS in mice. TLR4-small hairpin RNA (shRNA) lentivirus was injected intravenously into the mice to inhibit TLR4 expression. mRNA and protein levels were detected by real-time PCR and Western-blot analysis, respectively. The contents of the C-terminal propeptide of type I procollagen (PICP) in bronchoalveolar lavage fluid (BALF) were detected by ELISA, and the degree of fibrosis was detected by van Gieson collagen staining, the hydroxyproline assay, and alpha smooth muscle actin (α-SMA) immunohistochemical staining.</p> <p>Results</p> <p>Overexpression of TLR4, type I procollagen, alpha-SMA, and p-AKT in murine pulmonary tissue after intraperitoneal injection of LPS at 72 hours and 28 days were detected. Moreover, the degree of fibrosis was shown to increase by ELISA analysis of PICP in BALF, van Gieson collagen staining, the hydroxyproline assay, and α-SMA immunohistochemical staining. All of these changes were alleviated by intravenous infection with TLR4-shRNA lentivirus.</p> <p>Conclusions</p> <p>Inhibiting TLR4 signaling could ameliorate fibrosis at the early stage of ALI induced by LPS.</p
Power maximised and anti-saturation power conditioning circuit for current transformer harvester on overhead lines
The current transformer (CT) harvester is an effective and efficient solution due to its higher reliability and power density compared to other techniques. However, the current of overhead conductor fluctuates from tens of to thousands of amperes, which brings two challenges for the CT harvester design. First, the startup current, above which the harvester can independently power the monitoring devices, should be as low as possible, so that the battery capacity can be reduced; secondly, the magnetic core should be ensured unsaturated in high current condition. This paper proposes a power conditioning circuit with comprehensive control to maximize the output power and prevent the core from saturation. A prototype that can deliver 22.5 W power with 200 A is designed, and a control strategy based on the finite-state machine is implemented. Experimental results show that the startup current for 2 W load is about 30 A, and the core power density at 60 A is 45.96 mW/cm3, both of which are markedly improved compared to the reported results of the same condition
Novel communication method between power converters for DC micro-grid applications
Communication between power converters is vital for high performance DC micro-grids controls. However, for residential DC micro-grid applications, using external communication link would increase the system cost, and reduce the system flexibility and reliability. This paper presents a novel method to enable the conventional DC/DC converters to transmit data via the common DC Bus. With this technology, cost-effective low bandwidth communication links between power converters can be established within a DC micro-grid, and advanced distributed control algorithms can be developed. A reliable communication with 2 kbps transmission rate has been implemented between the Boost converters through the common input DC bus
DC power line communication based on power/signal dual modulation in phase shift full bridge converters
For intelligent DC distributed power systems, data communication plays a vital role in system control and device monitoring. To achieve communication in a cost effective way, power/signal dual modulation (PSDM), a method that integrates data transmission with power conversion, can be utilized. In this paper, an improved PSDM method using phase shift full bridge (PSFB) converter is proposed. This method introduces a phase control based freedom in the conventional PSFB control loop to realize communication using the same power conversion circuit. In this way, decoupled data modulation and power conversion are realized without extra wiring and coupling units, and thus the system structure is simplified. More importantly, the signal intensity can be regulated by the proposed perturbation depth, and so this method can adapt to different operating conditions. Application of the proposed method to a DC distributed power system composed of several PSFB converters is discussed. A 2kW prototype system with an embedded 5kbps communication link has been implemented, and the effectiveness of the method is verified by experimental results
Direct sequence spread spectrum based PWM strategy for harmonic reduction and communication
Switched mode power supplies (SMPSs) are essential components in many applications, and electromagnetic interference is an important consideration in the SMPS design. Spread spectrum based PWM strategies have been used in SMPS designs to reduce the switching harmonics. This paper proposes a novel method to integrate a communication function into spread spectrum based PWM strategy without extra hardware costs. Direct sequence spread spectrum (DSSS) and phase shift keying (PSK) data modulation are employed to the PWM of the SMPS, so that it has reduced switching harmonics and the input and output power line voltage ripples contain data. A data demodulation algorithm has been developed for receivers, and code division multiple access (CDMA) concept is employed as communication method for a system with multiple SMPSs. The proposed method has been implemented in both Buck and Boost converters. The experimental results validated the proposed DSSS based PWM strategy for both harmonic reduction and communication
Embedding Power Line Communication in Photovoltaic Optimizer by Modulating Data in Power Control Loop
In Photovoltaic (PV) system, dc-dc power optimizer (DCPO) is an option to maximize output power. At the same time, data links among DCPOs are often required for system monitoring and controlling. This paper proposes a novel power line communication (PLC) method for the DCPOs, in which the data of a DCPO is modulated into the control loop of power converter, and then transmitted through the series-connected dc power line to other DCPOs. In the process of communication, differential phase shift keying (DPSK) modulation and discrete Fourier transformation (DFT) demodulation are employed. To analyze the quality of communication, the communication model of the system is built, based on small-signal model. Furthermore, the noises of the system, including switching, maximum power point tracking (MPPT) and additive white Gaussian noise (AWGN), are discussed and measured to evaluate the signal-to-noise ratio (SNR). At last, an experimental system including 6 DCPOs is established and tested, which verifies the feasibility and effectiveness of the proposed method
A graph theory based energy routing algorithm in Energy Local Area Network (e-LAN)
The energy internet concept has been considered as a new development stage of the Smart Grid, which aims to increase the energy transmission efficiency and optimise the energy dispatching in time and space. Energy router is a core device in the energy internet and it connects all the devices together into a net structure and manages power flows among them. The research work presented in this paper described the energy router’s structure and function expectations from the network perspective, and improved the existing energy router design. Open-shortest-path first (OSPF) protocol and virtual circuit switching mode are referenced from the Internet in the energy local area network (e-LAN) design. This paper proposed a design of an energy routing algorithm based on graph theory in an e-LAN. A lowest-cost routing selection algorithm is designed according to the features of power transmission, and a source selection and routing design algorithm is proposed for very heavy load conditions. Both algorithms have been verified by case analyses
Answer Acquisition for Knowledge Base Question Answering Systems Based on Dynamic Memory Network
In recent years, with the rapid growth of Artificial Intelligence (AI) and the Internet of Things (IoT), the question answering systems for human-machine interaction based on deep learning have become a research hotspot of the IoT. Different from the structured query method in traditional Knowledge Base Question Answering (KBQA) systems based on templates or rules, representation learning is one of the most promising approaches to solving the problems of data sparsity and semantic gaps. In this paper, an answer acquisition method for KBQA systems based on a dynamic memory network is proposed, in which representation learning is employed to represent the natural language questions that are raised by users and the knowledge base subgraphs of the related entities. These representations are taken as inputs of the dynamic memory network. The correct answers are obtained by utilizing the memory and inferential capabilities. The experimental results demonstrate the effectiveness of the proposed approach. - 2013 IEEE.This work was supported by the National Science Foundation of China under Grant 61365010.Scopu
Generative Watermarking Against Unauthorized Subject-Driven Image Synthesis
Large text-to-image models have shown remarkable performance in synthesizing
high-quality images. In particular, the subject-driven model makes it possible
to personalize the image synthesis for a specific subject, e.g., a human face
or an artistic style, by fine-tuning the generic text-to-image model with a few
images from that subject. Nevertheless, misuse of subject-driven image
synthesis may violate the authority of subject owners. For example, malicious
users may use subject-driven synthesis to mimic specific artistic styles or to
create fake facial images without authorization. To protect subject owners
against such misuse, recent attempts have commonly relied on adversarial
examples to indiscriminately disrupt subject-driven image synthesis. However,
this essentially prevents any benign use of subject-driven synthesis based on
protected images.
In this paper, we take a different angle and aim at protection without
sacrificing the utility of protected images for general synthesis purposes.
Specifically, we propose GenWatermark, a novel watermark system based on
jointly learning a watermark generator and a detector. In particular, to help
the watermark survive the subject-driven synthesis, we incorporate the
synthesis process in learning GenWatermark by fine-tuning the detector with
synthesized images for a specific subject. This operation is shown to largely
improve the watermark detection accuracy and also ensure the uniqueness of the
watermark for each individual subject. Extensive experiments validate the
effectiveness of GenWatermark, especially in practical scenarios with unknown
models and text prompts (74% Acc.), as well as partial data watermarking (80%
Acc. for 1/4 watermarking). We also demonstrate the robustness of GenWatermark
to two potential countermeasures that substantially degrade the synthesis
quality
Wireless power and data transfer via a common inductive link using frequency division multiplexing
For wireless power transfer (WPT) systems, communication between the primary side and the pickup side is a challenge because of the large air gap and magnetic interferences. A novel method, which integrates bidirectional data communication into a high-power WPT system, is proposed in this paper. The power and data transfer share the same inductive link between coreless coils. Power/data frequency division multiplexing technique is applied, and the power and data are transmitted by employing different frequency carriers and controlled independently. The circuit model of the multiband system is provided to analyze the transmission gain of the communication channel, as well as the power delivery performance. The crosstalk interference between two carriers is discussed. In addition, the signal-to-noise ratios of the channels are also estimated, which gives a guideline for the design of mod/demod circuits. Finally, a 500-W WPT prototype has been built to demonstrate the effectiveness of the proposed WPT system
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