469 results on '"Pengyu Li"'
Search Results
152. The Effects of Air Pollution and Meteorological Factors in the Transmission and Lethality of COVID-19
- Author
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Ting Shi, Ailin Qi, Wu Yang, Pengyu Li, Chengxu Zhou, and Ke Gu
- Published
- 2023
153. FOXC2 marks and maintains the primitive spermatogonial stem cells subpopulation in the adult testis
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Zhipeng Wang, Cheng Jin, Pengyu Li, Yiran Li, Jielin Tang, Zhixin Yu, Tao Jiao, Jinhuan Ou, Han Wang, Dingfeng Zou, Mengzhen Li, Xinyu Mang, Jun Liu, Yan Lu, Kai Li, Ning Zhang, Shiying Miao, Jia Yu, Linfang Wang, and Wei Song
- Abstract
In adult mammals, spermatogenesis embodies the complex transition from spermatogonial stem cells (SSCs) to spermatozoa. This process is initiated by the dynamic transition among a series of SSCs subpopulations. However, it remains elusive and controversial for the identity of the primitive adult SSCs at the top of this developmental hierarchy. Using single-cell analysis and lineage tracing, we identified forkhead box protein C2 (FOXC2) as a specific marker for the primitive SSCs subpopulation in adult mice and humans. During homeostasis, FOXC2+-SSCs can initiate spermatogenesis, and through which give rise to all sets of spermatogenic progenies. Specific ablation of the FOXC2+-SSC results in depletion of the undifferentiated spermatogonia pool. During germline regeneration, spermatogenesis can be completely restored by FOXC2+-SSCs. Germ cell-specificFoxc2knockout resulted in accelerated exhaustion of SSCs and eventually led to male infertility. Mechanistically, FOXC2 is required for maintaining the quiescent state of the primitive SSCs by promoting the expression of negative regulators of cell cycle phase transition. Overall, this work proposed FOXC2+-SSCs as an indispensable and primitive subgroup during homeostasis and regeneration in the adult testis.
- Published
- 2022
154. Optimization of CNC machine processing parameters for low carbon manufacturing.
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Qian Yi, Ying Tang 0001, Congbo Li, and Pengyu Li
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- 2013
- Full Text
- View/download PDF
155. Software development for cloud and internet-of-things (IoT) based remotely controlled four-dimensional (4D) electrical resistivity tomography
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Zhen Wu, Ming Deng, Zucan Lin, Qisheng Zhang, Keyu Zhou, Pengyu Li, Yongdong Liu, Bentian Zhao, and Xingyuan Jiang
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congenital, hereditary, and neonatal diseases and abnormalities ,Wireless transmission ,Petroleum engineering ,business.industry ,General Chemical Engineering ,Fossil fuel ,Software development ,nutritional and metabolic diseases ,Cloud computing ,Environmental science ,Electrical resistivity tomography ,Groundwater resources ,Internet of Things ,business ,Instrumentation ,General Environmental Science - Abstract
Electrical resistivity tomography (ERT) is an important method for exploring oil and gas formations, mineral deposits, and groundwater resources. However, most ERT instruments have limitations such as complicated human���computer interaction, few measurement parameters, difficulties in remote monitoring, and lack of four-dimensional (4D) exploration functions. To overcome these limitations, in this study we proposed and developed software for a remote control 4D ERT system based on a cloud platform and Internet of Things (IoT) technology. Specifically, acquisition device control, channel and control, acquisition control, and remote monitoring systems were designed, with various modules being debugged and optimized multiple times. The system is equipped with a 4G module, through which the collected data are transmitted to the cloud platform to realize real-time, stable, and long-distance data acquisition and transmission. Furthermore, the system realizes remote monitoring, real-time measurement, and other functions via the cloud and IoT technology, thereby providing strong technical support for achieving 4D exploration. The developed system was empirically evaluated by applying it to explore the Gequ Landslide area in Jainca County, Qinghai Province, China. The exploration results indicate that the system software has stable functions and high intelligence; thus it satisfies the requirements for field exploration.
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- 2021
156. Reconstruction of severe acetabular bone defects with porous metal augment in total hip arthroplasty: A finite element analysis study
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Hao Tang, Zhenxian Chen, Zhongmin Jin, Yixin Zhou, Xiaogang Zhang, Pengyu Li, and Xiaoyu Liu
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Reoperation ,musculoskeletal diseases ,Orthodontics ,Porous metal ,Materials science ,Arthroplasty, Replacement, Hip ,Mechanical Engineering ,Finite Element Analysis ,Acetabulum ,General Medicine ,Initial stability ,musculoskeletal system ,Finite element method ,Prosthesis Failure ,Total hip revision ,Treatment Outcome ,Acetabular bone ,Humans ,Hip Prosthesis ,Augment ,Trabecular metal ,Porosity ,Total hip arthroplasty - Abstract
This study aims to evaluate the reconstructive stability for Paprosky III acetabular defects after total hip arthroplasty using three different reconstruction strategies with trabecular metal (TM) augments. The acetabular bone defects examined were located in the ilium, the sciatic ramus and the pubic ramus. Different scenarios of acetabular reconstructions were simulated, including the non-reconstruction model (NRM), the complete reconstruction model (CRM), the two-point reconstruction model (TRM) and the superior edge reconstruction model (SRM). A primary hip replacement model (HRM) was also investigated to compare the initial stability with different reconstruction models. The gait cycle was incorporated in the model to investigate the dynamic variation within the contact mechanics parameters. By comparing the SRM and the TRM, the acetabular cup translation was more pronounced when the superior defect on the acetabulum remained unfixed. Comparison of the acetabular cup displacement and the interface micromotion of both HRM and CRM demonstrated that the prosthetic implant provided good support for the reconstructed acetabulum. With the use of a press-fit cup, the cup displacement was reduced remarkably, while its Von-Mises stress increased significantly. The results show that the CRM was the best reconstruction option. In terms of acetabular defects, future improvements should focus on the reconstructive stability in stress concentration areas, to ensure no significant stress-shielding or other factors contributing to loosening of the prosthesis.
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- 2021
157. Development of an Expendable Current Profiler Based on Modulation and Demodulation
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Keyu Zhou, Qisheng Zhang, Guangyuan Chen, Zucan Lin, Yunliang Liu, and Pengyu Li
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Atmospheric Science ,Geology ,Oceanography - Abstract
We designed a low-cost expandable current profiler including software and hardware. An expendable current profiler (XCP) is an observation instrument that rapidly measures currents based on the principle that currents cut the geomagnetic field to induce electric fields. It is important to reduce the cost of an XCP because it is a single-use device. The digitization of the previously developed XCP is carried out underwater, which requires the probe to contain not only analogue circuits for acquiring signals but also digital circuits and digital chips, which are relatively expensive. In this study, an XCP has been developed that adopts signal modulation and demodulation to transmit analogue signals on an enamelled wire, and the signal digitization occurs above the surface of the water. The cost of the instrument is effectively reduced by half while maintaining the ability to measure parameters such as sea current and temperature in real-time. After comparison with data processed from laboratory tests, the acquisition circuit showed accuracy within one-thousandth of one per cent, and the XCP analogue circuit developed for the overall system was stable and reliable. The system exhibited an acquisition accuracy higher than 50 nV for 16 Hz, and the quality of the acquired signal met the requirements for an XCP instrument.
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- 2022
158. Intra-Cluster Federated Learning-Based Model Transfer Framework for Traffic Prediction in Core Network
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Pengyu Li, Yingji Shi, Yanxia Xing, Chaorui Liao, Menghan Yu, Chengwei Guo, and Lei Feng
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Computer Networks and Communications ,Hardware and Architecture ,Control and Systems Engineering ,traffic prediction ,core network ,federated learning ,Signal Processing ,Electrical and Electronic Engineering - Abstract
Accurate prediction of cellular traffic will contribute to efficient operations and management of mobile network. With deep learning, many studies have achieved exact cellular traffic prediction. However, the reality is that quite a few subnets in the core network do not have sufficient computing power to train their deep learning model, which we call subnets (LCP-Nets) with limited computing power. In order to improve the traffic prediction efficiency of LCP-Nets with the help of deep learning and the subnets (ACP-Nets) with abundant computing power under the requirement of privacy protection, this paper proposes an intra-cluster federated learning-based model transfer framework. This framework customizes models for LCP-Nets, leveraging transferring models trained by ACP-Nets. Experimental results on the public dataset show that the framework can improve the efficiency of LCP-Nets traffic prediction.
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- 2022
- Full Text
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159. Distributed AI-native Architecture for 6G Networks
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Pengyu Li, Yanxia Xing, and Wei Li
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- 2022
160. Discussion on 6G Network Architecture Based on Evolution
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Yanxia Xing, Pengyu Li, and Jinvan Li
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- 2022
161. Self-Powered SSDCI Array Interface for Multiple Piezoelectric Energy Harvesters
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Zhihe Long, Zhengbao Yang, Pengyu Li, Xingqi Zhang, Henry Shu-Hung Chung, Biao Wang, and Xiudeng Wang
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Computer science ,business.industry ,Interface (computing) ,020208 electrical & electronic engineering ,Electrical engineering ,02 engineering and technology ,Inductor ,law.invention ,Power (physics) ,Capacitor ,Rectifier ,Electricity generation ,law ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,business ,Energy harvesting ,Electronic circuit - Abstract
To merge the gap between the low-power output of piezoelectric energy harvesters (PEHs) and the high-power demand of sensors of Internet of Things, researchers recently start to explore PEHs arrays. However, few circuits have been developed to manage the multiple ac inputs from PEHs arrays. This article presents a self-powered PEH array interface circuit based on the synchronized switching and discharging to a storage capacitor through an inductor (SSDCI) technique. The array interface can output a maximum total power greater than the sum of each individual peak power, and achieve a high efficiency when multiple PEHs connect to the SSDCI array circuit. Simulation and experiment are performed to demonstrate the advantages of the SSDCI array interface. The tested results show that the designed SSDCI array circuit achieves an efficiency of 82.3% with three input sources, and allows a gain up to 300% in terms of maximal output power compared to the full-bridge rectifier. In addition, only the peak detection is utilized for the switching control; therefore, the SSDCI array circuit is realized more easily and with fewer components compared to the existing synchronous electric charge extraction array interfaces.
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- 2021
162. Internet-of-things-based four-dimensional high-density electrical instrument for geophysical prospecting
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Pengyu Li, Yongdong Liu, Zucan Lin, Keyu Zhou, Zhen Wu, Qisheng Zhang, Bentian Zhao, and Xingyuan Jiang
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,QC801-809 ,Computer science ,business.industry ,media_common.quotation_subject ,Geophysics. Cosmic physics ,Geology ,Cloud computing ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,Field (computer science) ,law.invention ,Data acquisition ,law ,Wireless ,The Internet ,Transceiver ,business ,Function (engineering) ,Remote control ,Computer hardware ,0105 earth and related environmental sciences ,media_common - Abstract
The high-density electrical method is a primary method used in shallow geophysical prospecting. Due to the rapid industrial development that has taken place in recent years, the function and performance of high-density electrical instruments have been considerably improved in several aspects. However, most of the electrical instruments currently available on the market still exhibit some shortcomings, such as being bulky, heavy, limited in their data acquisition accuracy, and difficult to connect to the Internet for remote monitoring. To address these problems, this study developed a new multifunctional four-dimensional (4D) high-density electrical instrument based on remote wireless communication technology. The system is small and lightweight, includes an integrated transceiver, has high data acquisition accuracy, and is capable of remote wireless real-time control. In this study, the hardware circuit was designed. The Arm all-in-one (AIO) LJD-eWinV5-ST7 with a 154.4 cm × 87 cm, 800 × 480 high-brightness wide-temperature-range display is used as the host computer, which has the advantages of small size, low power consumption, and abundant hardware resources. Internet of things (IoT) technology is incorporated in the system, and a 4G module is employed to provide a real-time remote control and data acquisition monitoring system based on the cloud platform. Tests showed that this instrument is stable and convenient to use and can meet the requirements for use in field prospecting.
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- 2021
163. Identification of quiescent FOXC2+ spermatogonial stem cells in adult mammals.
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Zhipeng Wang, Cheng Jin, Pengyu Li, Yiran Li, Jielin Tang, Zhixin Yu, Tao Jiao, Jinhuan Ou, Han Wang, Dingfeng Zou, Mengzhen Li, Xinyu Mang, Jun Liu, Yan Lu, Kai Li, Ning Zhang, Jia Yu, Shiying Miao, Linfang Wang, and Wei Song
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- 2023
- Full Text
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164. Matrix Completion with Cross-Concentrated Sampling: Bridging Uniform Sampling and CUR Sampling
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HanQin Cai, Longxiu Huang, Pengyu Li, and Deanna Needell
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FOS: Computer and information sciences ,Computer Science - Machine Learning ,Computational Theory and Mathematics ,Artificial Intelligence ,Applied Mathematics ,FOS: Mathematics ,Computer Vision and Pattern Recognition ,Numerical Analysis (math.NA) ,Mathematics - Numerical Analysis ,Software ,Machine Learning (cs.LG) - Abstract
While uniform sampling has been widely studied in the matrix completion literature, CUR sampling approximates a low-rank matrix via row and column samples. Unfortunately, both sampling models lack flexibility for various circumstances in real-world applications. In this work, we propose a novel and easy-to-implement sampling strategy, coined Cross-Concentrated Sampling (CCS). By bridging uniform sampling and CUR sampling, CCS provides extra flexibility that can potentially save sampling costs in applications. In addition, we also provide a sufficient condition for CCS-based matrix completion. Moreover, we propose a highly efficient non-convex algorithm, termed Iterative CUR Completion (ICURC), for the proposed CCS model. Numerical experiments verify the empirical advantages of CCS and ICURC against uniform sampling and its baseline algorithms, on both synthetic and real-world datasets.
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- 2022
165. CHD4 acts as a critical regulator in the survival of spermatogonial stem cells in mice
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Pengyu, Li, Jielin, Tang, Zhixin, Yu, Cheng, Jin, Zhipeng, Wang, Mengzhen, Li, Dingfeng, Zou, Xinyu, Mang, Jun, Liu, Yan, Lu, Shiying, Miao, Linfang, Wang, Kai, Li, and Wei, Song
- Subjects
Male ,DNA-Binding Proteins ,Mice ,Adult Germline Stem Cells ,Reproductive Medicine ,DNA Helicases ,Animals ,Cell Differentiation ,Cell Biology ,General Medicine ,Spermatogenesis ,Spermatogonia ,Transcription Factors - Abstract
Spermatogenesis is sustained by homeostatic balance between the self-renewal and differentiation of spermatogonial stem cells, which is dependent on the strict regulation of transcription factor and chromatin modulator gene expression. Chromodomain helicase DNA-binding protein 4 is highly expressed in spermatogonial stem cells but roles in mouse spermatogenesis are not fully understood. Here, we report that the germ-cell-specific deletion of chromodomain helicase DNA-binding protein 4 resulted in complete infertility in male mice, with rapid loss of spermatogonial stem cells and excessive germ cell apoptosis. Chromodomain helicase DNA-binding protein 4-knockdown in cultured spermatogonial stem cells also promoted the expression of apoptosis-related genes and thereby activated the tumor necrosis factor signaling pathway. Mechanistically, chromodomain helicase DNA-binding protein 4 occupies the genomic regulatory region of key apoptosis-related genes, including Jun and Nfkb1. Together, our findings reveal the determinant role of chromodomain helicase DNA-binding protein 4 in spermatogonial stem cells survival in vivo, which will offer insight into the pathogenesis of male sterility and potential novel therapeutic targets.
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- 2022
166. Polyacrylonitrile fiber‐based heterogeneous catalysts for organic transformations
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Juntao Zhang, Pengyu Li, Yu Yang, Wenying Ai, Yuanyuan Liu, and Wenqin Zhang
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General Chemistry - Published
- 2022
167. Bubble energy generator
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Xiantong Yan, Wanghuai Xu, Yajun Deng, Chao Zhang, Huanxi Zheng, Siyan Yang, Yuxin Song, Pengyu Li, Xiaote Xu, Yue Hu, Luwen Zhang, Zhengbao Yang, Steven Wang, and Zuankai Wang
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Multidisciplinary - Abstract
Bubbles have been extensively explored as energy carriers ranging from boiling heat transfer and targeted cancer diagnosis. Yet, despite notable progress, the kinetic energy inherent in small bubbles remains difficult to harvest. Here, we develop a transistor-inspired bubble energy generator for directly and efficiently harvesting energy from small bubbles. The key points lie in designing dielectric surface with high-density electric charges and tailored surface wettability as well as transistor-inspired electrode configuration. The synergy between these features facilitates fast bubble spreading and subsequent departure, transforms the initial liquid/solid interface into gas/solid interface under the gating of bubble, and yields an output at least one order of magnitude higher than existing studies. We also show that the output can be further enhanced through rapid bubble collapse at the air/liquid interface and multiple bubbles synchronization. We envision that our design will pave the way for small bubble-based energy harvesting in liquid media.
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- 2022
168. A secondary modulation mechanism for aerofoil tonal self-noise generation
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Yannian Yang, Stefan Pröbsting, Pengyu Li, Yu Liu, and Ye Li
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Mechanics of Materials ,Mechanical Engineering ,Condensed Matter Physics - Abstract
Acoustic emission of a NACA 0012 aerofoil is investigated over a range of free-stream velocities. Acoustic spectra show a dominant tone and two sets of weaker side tones characterised by different frequency intervals. The frequency of the dominant tones in the acoustic spectra varies with velocity in a ladder-type structure. With increasing Reynolds number, the spectrum becomes progressively more broadband in nature. Through synchronised particle image velocimetry and acoustic measurements, the aeroacoustic noise generation mechanisms, resulting in different spectral characteristics and modulation types, are further investigated. A separation bubble and related significant velocity fluctuations are observed on the pressure side. Pressure side velocity spectra show characteristics similar to the acoustic ones, whereas velocity spectra on the suction side feature broadband characteristics. These findings confirm that noise emission is dominated by pressure side events for the Reynolds number range of this study, i.e. $2 \times 10^{5}$ – $7 \times 10^{5}$ . As the acoustic emission is defined by coherent flow structures, the proper orthogonal decomposition method is adopted to facilitate the understanding of the relation between the complex flow field and acoustic emission. Side tones in the acoustic spectra are attributed to two different modulation mechanisms in the aeroacoustic source region near the trailing edge. By aligning the sound pressure time history and the time coefficients of the dominant modes, the primary modulation of the dominant tone is found to be related to the amplitude modulation of the high-frequency velocity fluctuations associated with the acoustic feedback loop. A secondary modulation is attributed to periodic variation of the separation bubble and, therefore, variation in the roll-up of the shear layer, which results in a modulation of the amplitude of the velocity fluctuations associated with the convecting vortices at the trailing edge.
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- 2022
169. Novel Reclosing Strategy Based on Transient Operating Voltage in Pseudobipolar DC System With Mechanical DCCB
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Bin Li, Pengyu Li, Chong Gao, Ning Zhang, Chengshan Wang, Weijie Wen, and Haijin Liu
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Computer science ,020208 electrical & electronic engineering ,Direct current ,02 engineering and technology ,Fault (power engineering) ,Reliability engineering ,law.invention ,Capacitor ,Reliability (semiconductor) ,Electric power transmission ,law ,0202 electrical engineering, electronic engineering, information engineering ,Transient (oscillation) ,Electrical and Electronic Engineering ,Circuit breaker ,Voltage - Abstract
To ensure the reliability and flexibility of direct current (dc) system, direct current circuit breakers (DCCBs) are in urgent demand. Compared with solid-state and hybrid DCCBs, mechanical DCCBs have features of low operating losses and investment, showing bright application prospects. Until now, without concern about transient operating voltages (TOV) in the whole dc system, the reclosing of DCCB is still an open problem, and it is the emphasis of this article. First, overview of TOV in typical pseudobipolar dc system is introduced. Then, focused on hardware, electrical characteristic of a novel mechanical DCCB is analyzed, and verification tests are carried out in our laboratory. By taking interaction between the dc system, DCCB, and lines into consideration, distribution patterns of TOV under different faults and its mechanism are revealed. Based on TOV, novel reclosing strategy is proposed for mechanical DCCBs, and case studies are conducted in PSCAD/EMTDC for verification. Remarkable advantages of novel reclosing strategy are: fault type could be identified without operating any component of DCCB after fault current interruption; no risk of reclosing a permanent fault point; an explicit time could be reserved for the dielectric recovery of temporary fault point.
- Published
- 2021
170. Solvent Selective Polyacrylonitrile Fiber as a Recyclable Catalyst for the Knoevenagel-Michael Reaction in Water
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Jiali Lu, Wenqin Zhang, Lingrui Hu, Yu Yang, Weihua Chen, Xueling Wu, and Pengyu Li
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Thermogravimetric analysis ,chemistry.chemical_compound ,Differential scanning calorimetry ,Chemical engineering ,Chemistry ,Polyacrylonitrile ,Knoevenagel condensation ,Thermal stability ,General Chemistry ,Fiber ,Heterogeneous catalysis ,Catalysis - Abstract
Heterogeneous catalysis is an important branch of sustainable chemistry. In this work, a series of polyacrylonitrile fiber (PANF) fiber catalysts (PANF-E, PANF-EDs, and PANF-D) with different catalytic micro-environments are developed and characterized by elemental analysis, Fourier-transfer infrared spectroscopy, x-ray diffraction, thermogravimetric/differential scanning calorimetry analysis, scanning electron microscopy, and mechanical strength measurements to demonstrate the successful immobilization of the different amines as well as evaluate the physical strength and thermal stability of the fiber catalysts at different stages. The catalytic activities of the fiber catalysts are tested by one-pot three-component Knoevenagel-Michael reaction to the synthesis of substituted 2-amino-4H-chromenes in which the influences of surface polarities, kinds and proportions of functional groups on the fiber catalysts activities were investigated. Among the prepared catalysts, the PANF-D with higher density of tertiary amino group and hydrophilic micro-environment exhibited the best catalytic activity to efficiently catalyze the three-component reaction in water with excellent substrate suitability (92-98%). In addition, the catalyst can be easily separated from the catalytic system and conveniently reused at least ten times. Moreover, the PANF-D performs well in scaled-up experiment in a simple fixed-bed reactor with a yield of 97% which allows it to have great potential for further cleaner industrial applications.
- Published
- 2021
171. RF Energy Harvesting for Batteryless and Maintenance-Free Condition Monitoring of Railway Tracks
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Zhengbao Yang, Pengyu Li, and Zhihe Long
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Computer Networks and Communications ,business.industry ,Computer science ,020209 energy ,010401 analytical chemistry ,RF power amplifier ,Electrical engineering ,Condition monitoring ,02 engineering and technology ,Track (rail transport) ,01 natural sciences ,0104 chemical sciences ,Computer Science Applications ,Hardware and Architecture ,Rail transportation ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,Wireless ,Voltage multiplier ,Wireless power transfer ,Structural health monitoring ,business ,Wireless sensor network ,Energy harvesting ,Information Systems - Abstract
Current railway track condition monitoring relies on inefficient human inspectors and expensive inspection vehicles, where high-frequency inspection is unreachable since these methods occupy the tracks. This article proposes a batteryless railway monitoring system based on radio-frequency (RF) energy harvesting to detect early defects on rail tracks. The key part of the system is a batteryless wireless sensor tag (BLWST) installed on railway tracks. The BLWST can harvest RF energy from a reader installed on the train, and precisely measure and wirelessly transmit the vibration condition of tracks back to the reader. The proposed system eliminates the demands for cables and battery replacement, thus achieving low installation and maintenance costs. The high-frequency monitoring also provides a more reliable inspection than the existing methods. The BLWST is based on the 3-stage Dickson voltage multiplier (DVM) and can be activated by a dedicated RF power source at a maximum distance of 2.3 m. Experiments show that a maximum energy conversion efficiency of 25% and 500 working cycles per second are achieved. For demonstration, we construct a miniaturized railway system with the batteryless prototype and exhibit a reliable wireless power transfer and data communication.
- Published
- 2021
172. Progress in Construction and Food Application of Chitosan-based Nutrient Delivery System
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Pengyu LIU, Kexin WANG, Yuyuan ZHOU, Yan YANG, Zhuqing XING, and Ang GAO
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chitosan ,delivery system ,bioactive substances ,sustained release performance ,carrier construction ,Food processing and manufacture ,TP368-456 - Abstract
Chitosan is a naturally-occurring alkaline polysaccharide with excellent biocompatibility, biodegradability, low toxicity, and easy preparation. It has been widely used in the construction of delivery systems for various nutrients and bioactive substances. The chitosan-based nutrient delivery systems are mainly constructed by cross-linking, drying, layer-by-layer self-assembly, coalescence, covalent grafting, microfluidics and biosynthesis. Chitosan can be combined with carbohydrates, proteins and liposomes to form a composite carrier that can obtain more excellent performance and broaden its application in food packaging materials, slow release of bioactive substances and probiotic embedding. In addition, this paper further analyzes the obstacles and limitations of the actual application of chitosan-based nutrient delivery systems in the food industry, to provide important references for the application of chitosan-based delivery carriers in imparting new functional properties to foods, developing new food ingredients, and nutrient fortification.
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- 2024
- Full Text
- View/download PDF
173. Development of an expendable current profiler and simulation of passive sources
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Keyu Zhou, Guangyuan Chen, Qisheng Zhang, Zucan Lin, Yunliang Liu, Xingyuan Jiang, Jinhang Zhang, and Pengyu Li
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Applied Mathematics ,Instrumentation ,Engineering (miscellaneous) - Abstract
A common approach to ocean current measurement is to use a motion-induced electric field; this is the basic principle of the expendable current profiler (XCP). However, existing studies into XCPs have not explored indoor simulations of the ocean current environment or the implementation of attitude correction in the hardware. The accuracy of XCPs can be verified via indoor experiments and is affected by the sinking attitude. Therefore, in this study, we develop an XCP to measure ocean information in real time, and we correct the data for different XCP sinking attitudes. Furthermore, we design electromagnetic-induction-based laboratory measurements of simulated dynamic ocean currents. The signals collected by the XCP are linearly related to the copper-plated-power-supply signal. The processed data are compared and the feasibility of extracting ocean current signals via electrodes is verified through laboratory simulations of XCPs. Furthermore, we performed marine experiments in the South China Sea; the results indicate that the system is stable and easy to use. We implemented an expendable conductivity-temperature-depth system at the same location; the curve trends measured by the two probes were consistent, and the maximum error was found to be 0.5 °C. We expect this work to improve the quality of ocean current measurements and subsequent monitoring capabilities.
- Published
- 2023
174. Multiparameter seismic behavior of castellated beam-to-column connections based on stress migration
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Pengyu Li, Ran Bi, Qinghe Wang, and Lianguang Jia
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Materials science ,business.industry ,0211 other engineering and technologies ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,0201 civil engineering ,Stress (mechanics) ,Buckling ,Stress migration ,021105 building & construction ,Architecture ,Plastic hinge ,Bearing capacity ,Safety, Risk, Reliability and Quality ,business ,Ductility ,Beam (structure) ,Civil and Structural Engineering ,Stress concentration - Abstract
This paper presents a study on the castellated beam-to-column connections with four regular hexagonal web openings and one solid web beam-to-column connection that considering the opening rate and whether there is a combination of floor slabs (composite action) while subjected to the cyclic loading. Furthermore, the initial geometric imperfection was carefully incorporated in the FE model and the models have been validated against published experimental results. There is a slightly different about 5% between FE and test results including ultimate bearing capacity and other hysteresis behaviors. Investigation of 38 FE models subjected to cyclic loading focuses in the variation regularity of the failure mode, plastic development, stress migration, and seismic behaviors under the coupling effect of various factors, including the composite action of the floor slab, opening rate, the distance from the first opening to the face of the column, depth-to-thickness ratio of the web, and opening spacing. It is found that the composite action can improve the stress distribution around the first opening and raise the bearing capacity and ductility of the connections to a certain extent. Further, when the opening rate is either smaller than 0.5 or higher than 0.7, the plastic hinge of the connections with the floor slab occurs at the beam-to-column connection weld, which is completely different from the failure mode that without composite action. When the distance from the first opening to the face of the column is equal to or greater than 1.375 times the depth of beam, the plastic hinge formed in the beam-to-column weld while the composite action is taken into account; when disregarding the composite action causes the plastic hinge emerged in the beam section. Also, the ultimate bearing capacity of the castellated beam-to-column connections with closely spaced web openings significantly decreases; however, widely spaced web openings make stress concentration around the first opening and hinder the migration of stress to other openings, which has an adverse effect on the ultimate bearing capacity and ductility of the connections. The depth-to-thickness ratio of the web is also an important factor affecting the damage mode either web buckling or beam plastic hinge.
- Published
- 2021
175. Data mining-based study of collagen type III alpha 1 (COL3A1) prognostic value and immune exploration in pan-cancer
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Yatong Li, Pengyu Li, Zhangping Yu, Menghua Dai, Hanyu Zhang, Cheng Xing, Shunda Wang, Lixin Chen, and Cheng Ding
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Collagen, type III, alpha 1 ,COL3A1 ,pan-cancer ,Bioengineering ,Biology ,Applied Microbiology and Biotechnology ,Extracellular matrix ,Focal adhesion ,Immune system ,Downregulation and upregulation ,Neoplasms ,tumor microenvironment ,Data Mining ,Humans ,Protein Interaction Maps ,Tumor microenvironment ,immune analysis ,General Medicine ,Prognosis ,Actin cytoskeleton ,Collagen Type III ,Cancer research ,Transcriptome ,TP248.13-248.65 ,CD8 ,Research Article ,Research Paper ,Biotechnology - Abstract
The extracellular matrix (ECM) shows an essential effect during the occurrence and procession of human cancers. Type III collagen is a crucial component of ECM. Collagen Type III Alpha 1(COL3A1) is aberrantly expressed in a variety of cancers. Nevertheless, the role of COL3A1 in pan-cancer stays unidentified. In this study, we explored public databases, including Cancer Genome Atlas (TCGA), GTEx, GEPIA, cBioPortal, Oncommine, TIMER and GENEMANIA databases to identify the differential expression of COL3A1 in human cancer tissues and normal samples, followed by its prognostic value for patient survival. In addition, we explore the association between COL3A1 expression and immune infiltration. Further, we used the GeneMANIA database and Gene Set Enrichment Analysis (GSEA) to investigate Protein–Protein Interaction (PPI) and gene functional enrichment. Results show that COL3A1 expressed higher in tumor samples than in normal samples. Upregulation of COL3A1 is associated with a worse prognosis and a more advanced cancer stage. COL3A1 expression shows significant positive correlations with tumor-infiltrating immune cells (TIICs), including neutrophils, macrophages, CD8 + T cells, CD4 + T cells, dendritic cells, and B cells. Markers of TIICs demonstrated distinct patterns of COL3A1-related immune infiltration. COL3A1 expression was associated with ECM receptor interaction, regulation of actin cytoskeleton and focal adhesion pathways via GSEA analysis. In conclusion, COL3A1 may be a molecular biomarker for prognosis and immune infiltration in pan-cancer. It might act as a potential target for a new insight of human cancers management., graphical
- Published
- 2021
176. A wood-templated unidirectional piezoceramic composite for transmuscular ultrasonic wireless power transfer
- Author
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Pengyu Li, Ying Hong, Shiyuan Liu, Tian Yang, Lihan Jin, Zhuomin Zhang, Bee Luan Khoo, Zhihe Long, Zhengbao Yang, Junchen Liao, Biao Wang, Youngjin Lee, and Bing He
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electrical engineering ,Topology (electrical circuits) ,Pollution ,Piezoelectricity ,Power (physics) ,Nuclear Energy and Engineering ,Environmental Chemistry ,Wireless ,Ultrasonic sensor ,Wireless power transfer ,business ,Voltage ,Power density - Abstract
Bioelectronic devices implanted within the human body are increasingly used for diagnostic and therapeutic purposes, of which functions and lifespan could be significantly improved with the wireless energy transfer technology. However, limited by the electromagnetic radiation, low power output, high stiffness, short transfer distance and tissue attenuation, most wireless energy transfer systems cannot meet the requirements of implantable medical devices (IMDs). Here, inspired by the natural wood structures, we present a transmuscular ultrasonic wireless power transfer system based on a flexible wood-templated piezoelectric ultrasonic energy harvester (W-PUEH) in a unidirectional 3D interconnected ceramic-polymer topology. The developed flexible W-PUEH device demonstrates an output voltage of 21 V, an output current of 2 mA, and an average output power density of 304 μW cm-2, one order of magnitude higher than the state of the art. Further ex vivo and in vivo experiments demonstrate the sufficient power supply capacity of the W-PUEH and its potential applications in the implantable devices for the improvement of life quality and well-being of the recipients.
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- 2021
177. Minor alkyl modifications for manipulating the fluorescence and photomechanical properties in molecular crystals
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Junxiao Wang, Meizhen Yin, Pengfei Li, Pengyu Li, and Liming Lai
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chemistry.chemical_classification ,Materials science ,Intermolecular force ,Photochemistry ,Fluorescence ,Crystal ,Coupling (electronics) ,chemistry ,Materials Chemistry ,Molecule ,General Materials Science ,Reactivity (chemistry) ,Irradiation ,Alkyl - Abstract
Responsive fluorescent solid-state materials, especially light-driven mechanical motions, have received interest owing to the potential applications in advanced smart reponsive devices. However, control of the dynamic photoresponsive behavior and static fluorescence of molecular crystals based on the same molecule remains a great challenge. Herein, we present a concise molecular design by minor modification of the alkyl groups of cyanostilbene derivatives (CS), allowing control of the solid-state fluorescence and photomechanical behaviours in the crystal state. The CSEt crystal with shorter alkyl groups exhibits negligible fluorescence (ΦF = 0.2%) due to the strong intermolecular coupling. The high [2+2] photocycloaddition reactivity of the CSEt microcrystal leads to the light-driven crystal bending and cracking. Meanwhile, the fluorescence of the CSEt crystal increased with UV irradiation and force grinding, exhibiting dual stimuli-responsive fluorescence “turn-on”. For propyl-modified CSPr, the intermolecular coupling is weakened by the longer alkyl groups, achieving high fluorescence quantum yields (ΦF = 84%) and excellent photostability to UV light. Furthermore, the CSEt crystal exhibits dual stimuli-responsive fluorescence “turn-on” to UV light and force grinding. This work provides new insight for controlling the optical properties and investigating the effects of the molecular stacking pattern.
- Published
- 2021
178. Panoramic transcriptome analysis and functional screening of long noncoding RNAs in mouse spermatogenesis
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Shunshun Zhong, Jia Yu, Zhipeng Wang, Shiying Miao, Yan Lu, Cheng Jin, Linfang Wang, Yanyun Luo, Mengzhen Li, Ruiqin Han, Bo Wen, Kai Li, Yanmin Si, Xinyu Mang, Qing Zhao, Jiayue Xu, Dingfeng Zou, Fang Wang, Pengyu Li, Yanni Ma, and Wei Song
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Male ,Biology ,Regulatory region ,Transcriptome ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Gene expression ,Genetics ,medicine ,Animals ,Spermatogenesis ,Gene ,Genetics (clinical) ,030304 developmental biology ,0303 health sciences ,Functional analysis ,Research ,Gene Expression Profiling ,Lncrna expression ,Spermatids ,Cell biology ,medicine.anatomical_structure ,RNA, Long Noncoding ,030217 neurology & neurosurgery ,Germ cell - Abstract
Long noncoding RNAs (lncRNAs) have emerged as diverse functional regulators involved in mammalian development; however, large-scale functional investigation of lncRNAs in mammalian spermatogenesis in vivo is lacking. Here, we delineated the global lncRNA expression landscape in mouse spermatogenesis and identified 968 germ cell signature lncRNAs. By combining bioinformatics and functional screening, we identified three functional lncRNAs (Gm4665, 1700027A15Rik, and 1700052I22Rik) that directly influence spermatogenesis in vivo. Knocking down Gm4665 hampered the development of round spermatids into elongating spermatids and disrupted key spermatogenic gene expression. Mechanistically, lncRNA Gm4665 localized in the nucleus of round spermatids and occupied the genomic regulatory region of important spermatogenic genes including Ip6k1 and Akap3. These findings provide a valuable resource and framework for future functional analysis of lncRNAs in spermatogenesis and their potential roles in other biological processes.
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- 2020
179. Chirality of Perylene Diimides: Design Strategies and Applications
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Jie Li, Pengyu Li, Mingyu Fan, Xian Zheng, Jun Guan, and Meizhen Yin
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General Chemistry ,General Medicine ,Imides ,Perylene ,Catalysis - Abstract
Chirality is a particularly important concept in nature and exists at all length scales, ranging from the molecular level to the supramolecular level. Over the last two decades, various design strategies have been developed to construct chiral materials based on perylene diimides (PDIs) and to mimic the chiral assembly process in biological systems, but applications of these chiral aggregates are still at an early stage. This Minireview summarizes recent progress in the synthesis and properties of chiral PDIs. The chirality in PDI-based materials can be generated by three different approaches: from the twisted planes of PDIs, the chiral substituents of PDIs, and the co-assembly of achiral PDIs and chiral guests. A comprehensive understanding of the applications of chiral PDIs as well as potential future developments is also provided.
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- 2022
180. Suboptimal immune recovery and associated factors among people living with HIV/AIDS on second-line antiretroviral therapy in central China: A retrospective cohort study
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Keying Zhu, Qianlei Xu, Yanmin Ma, Pengyu Li, Huangchao Jia, Qi Jiang, Yueyuan Wang, Zhihui Wu, Dongli Wang, Huijun Guo, and Yantao Jin
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Male ,Acquired Immunodeficiency Syndrome ,Infectious Diseases ,Anti-Retroviral Agents ,Anti-HIV Agents ,Virology ,Quality of Life ,Humans ,Female ,HIV Infections ,Viral Load ,CD4 Lymphocyte Count ,Retrospective Studies - Abstract
The introduction and scale-up of antiretroviral therapy (ART) have contributed to significantly improved patients with acquired immune deficiency syndrome (AIDS) quality of life and prolongs their survival. This has occurred by suppressing viral replication and recovering the CD4 cell count. However, some patients do not normalize their CD4 cell count, despite suppression of the viral load (VL). Patients with suboptimal immune recovery (SIR), as defined by a VL 400 copies/ml with a CD4 cell count of200 cells/μl, after ART initiation, exhibit severe immune dysfunction and have a higher risk of AIDS and non-AIDS events. In recent years, People living with HIV/AIDS (PLWHA) with first-line ART failure began to gradually switch to second-line ART. This study aimed to examine the prevalence and factors affecting SIR among PLWHA who switch to second-line ART in rural China. A 1-year retrospective cohort study was conducted among PLWHA who switched to second-line ART between January 2009 and December 2018. All patients with a VL 400 copies/ml after 1 year of second-line ART were included. SIR was defined as a CD4 cell count200 cells/μl and a VL 400 copies/ml after 1 year of second-line ART. The data collected from medical records were analyzed by univariate and multivariate analyses. A total of 5294 PLWHA met the inclusion criteria, 24 died, and 1152 were lost to follow-up after 1 year of second-line ART. Among 4118 PLWHA who were followed up, 3039 with a VL 400 copies/ml had their data analyzed, and the prevalence of SIR was 13.1%. The patients' mean age at recruitment was 47.6 ± 8.1 years and 45.3% were men. A total of 30.7% of patients were HIV-positive for8 years and 88.2% were receiving ART before starting second-line ART for3 years. The mean CD4 cell count was 354.8 ± 238.2 cells/μl. A multivariable analysis showed that male sex, single status (unmarried or divorced), and a low CD4 cell count were risk factors for SIR among PLWHA with second-line ART. The prevalence of SIR among PLWHA who switched to second-line ART in this retrospective cohort study is lower than that in most other studies. Several factors associated with SIR include male sex, marital status, and CD4 cell count levels in PLWHA.
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- 2022
181. Abnormal percent amplitude of fluctuation and functional connectivity within and between networks in benign epilepsy with centrotemporal spikes
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Ke Xu, Fuqin Wang, Bowen Geng, Ying Peng, Shuming Zhang, Pengyu Li, Duoli Chen, Xiao Zeng, Heng Liu, and Peng Liu
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Brain Mapping ,Neurology ,Brain ,Humans ,Neurology (clinical) ,Child ,Epilepsy, Rolandic ,Magnetic Resonance Imaging ,Frontal Lobe - Abstract
Benign epilepsy with centrotemporal spikes (BECTS) is one of the most common childhood epilepsy syndromes. The neural basis of BECTS is still poorly understood. This study aimed to further investigate the possible neural mechanisms of BECTS by comparing percent amplitude of fluctuation (PerAF) of resting-state functional magnetic resonance imaging (RS-fMRI) signal of each brain voxel and connectivity within and between related networks in children with BECTS and healthy controls (HCs).Firstly, we used PerAF method to investigate brain functional alteration and defined the regions of interest (ROIs) where children with BECTS exhibited significant PerAF alterations compared to HCs. We then divided these ROIs into different networks based on previous findings and investigated alterations of functional connectivity within and between networks in children with BECTS. Receiver operating characteristic (ROC) curve was employed to assess the reliable biomarker for distinguishing children with BECTS from HCs based on the intergroup PerAF differences.Children with BECTS showed decreased PerAF in the left middle frontal cortex (MFC), right precentral gyrus, left precuneus (PCUN), bilateral posterior cingulate cortex (PCC), left angular gyrus, left inferior parietal lobule (IPL), right supplementary motor area (SMA) and left primary somatosensory cortex (S1) compared to HCs. The IPL and PCC exhibited higher classification power by ROC analysis. Moreover, our findings exhibited increased Intra-network connectivity in the default mode network (DMN), and increased inter-network connectivity of the sensorimotor network (SMN) with Broca's area and DMN.Our study investigated the abnormal PerAF and functional brain networks in children with BECTS, which might provide new insights into the pathological mechanisms of BECTS.
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- 2022
182. Changes of insular function in lifelong premature ejaculation patients before and after SSRI administration
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Ming Gao, Bowen Geng, Shuming Zhang, Ke Xu, Pengyu Li, Duoli Chen, Xiao Zeng, Peng Liu, and Yanzhu Wang
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Pharmacology ,Male ,Benzylamines ,Humans ,Brain ,Premature Ejaculation ,Naphthalenes ,Magnetic Resonance Imaging ,Selective Serotonin Reuptake Inhibitors - Abstract
Lifelong premature ejaculation (PE) is regarded as one of the most common male sexual dysfunction. We aimed to detect whether insula-related brain functional networks are altered in lifelong PE patients and whether such alterations are "normalised" after selective serotonin reuptake inhibitors (SSRI) administration.Twenty-three drug-naive lifelong PE patients and 30 healthy controls (HC) were recruited in current study. All subjects underwent resting-state functional magnetic resonance imaging (fMRI) scan at first. One hour after dapoxetine administration, all patients underwent fMRI scanning again. The degree centrality (DC), amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) analysis, and ROI-based functional connectivity (FC) analysis were applied to calculate the abnormalities in insula-related functions among three groups.Compared to HC group, PE patients at baseline showed significantly altered DC, ALFF, and ReHo value of the bilateral insula, which subsequently showed a "normalised" trend after dapoxetine administration. Additionally, compared to HC group, PE patients at baseline showed significantly decreased FC between insula and precentral gyrus, inferior frontal gyrus, middle/inferior temporal gyrus, and caudate, while patients after dapoxetine administration showed increased insula-related FC in anterior cingulate cortex and decreased FC in thalamus and middle/inferior temporal gyrus. The main effects of dapoxetine were located in precentral gyrus, inferior frontal gyrus, caudate, and limbic system.Our findings report altered brain mechanism of insula in lifelong PE patients and also indicate that dapoxetine can "normalise" the abnormal function of the insula to certain extent in lifelong PE patients.
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- 2022
183. The prevalence of HIV-infected patients with virological suppression but a CD4+ T-cell count of ? 200 cells/mm3 after highly active antiretroviral therapy initiation: A meta-analysis
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Zhihui Wu, Yueyuan Wang, Zhibin Liu, Pengyu Li, Huijun Guo, Yuqing Ma, Zhenkui Zhang, Chunling Yang, and Yantao Jin
- Subjects
medicine.medical_specialty ,Cd4 t cell ,business.industry ,virus diseases ,General Medicine ,Cochrane Library ,Antiretroviral therapy ,Confidence interval ,Infectious Diseases ,Meta-analysis ,Internal medicine ,Medicine ,Hiv infected patients ,Pharmacology (medical) ,business ,Viral load ,Cohort study - Abstract
Highly active antiretroviral therapy (HAART) strongly inhibits HIV replication. However, many patients show suboptimal immune recovery (SIR), as defined by virological suppression (i.e. low viral load) with a CD4+ T-cell count of ≤ 200 cells/mm3, after HAART initiation. Here, we performed a systematic evaluation of the SIR prevalence among HIV-infected patients in cohort studies. We searched PubMed, Cochrane Library, Embase, CNKI, Wanfang database, and Chinese Biomedicine Database for cohort studies about HIV-infected participants whose CD4+ T-cell count was ≤ 200 cells/mm3 but still had virological suppression after HAART initiation. The SIR prevalence from each of those cohort studies was pooled into a random-effect meta-analysis. We obtained two kinds of pooled post-HARRT initiation SIR prevalence: one among participants with virological suppression (11 cohort studies involving 18,672 participants), and the other among all HIV-infected participants (seven cohort studies involving 12,063 participants). The pooled SIR prevalence among HIV-infected patients with virological suppression after HAART initiation was 43% (95% confidence interval [CI], 34-51%) at 6 months post-HAART initiation and 10% (95% CI, 5-18%) at 36 months post-HAART initiation; among all HIV-infected patients after HAART initiation, it was 17% (95% CI, 0-55%) and 5% (95% CI, 2-10%) at 6 and 36 months post-HAART initiation, respectively. The SIR prevalence among HIV-infected patients is high at 6 months post-HAART initiation, but its prevalence gradually reduces over time under continuous HAART. Thus, it is important to follow-up on variations in the CD4+ T-cell count and viral load.
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- 2022
184. Synthesis and washing aid properties of a polycarboxylate copolymer.
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Dangge Gao, Pengyu Li, Shuzhen Yu, Wei Liu, and Bin Lv
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ACRYLIC acid ,SODIUM tripolyphosphate ,SUCCINIC acid ,SURFACE tension ,CARBOXYLATES ,CARBOXYLATE derivatives ,PH effect - Abstract
Poly(ESA-AA-SAS-HPA) w a s synthesized by solution polymerization from epoxy succinic acid (ESA), acrylic acid (AA), sodium allyl sulfonate (SAS) and hydroxypropyl acrylate (HPA). It was characterized by FT-IR, ¹H NMR, TG and DLS. The effects of chelating pH, temperature and additive mass fraction on the washing aid performance of Poly(ESA-AA-SAS-HPA) were investigated. The results show that, compared with sodium tripolyphosphate, it has good washing aid performance, with the chelating amount of 308.7 mg/g and the calcium dispersing power of 101.5 mg/g. Poly (ESA-AA-SAS-HPA) has good synergism with sodium dodecylbenzene sulfonate (LAS), which can reduce the surface tension of the system to 45 mN/m. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
185. Sound Source Localization Method of Substation Based on Fourth-order Cumulant
- Author
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Pengyu, Li, primary, Shuai, Yan, additional, Gaojie, Wang, additional, Bing, Hu, additional, Kunpeng, Wang, additional, and Ran, Tao, additional
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- 2022
- Full Text
- View/download PDF
186. Transparent Conducting TiO2 Thin Film Induced by Electric‐Field Controlled Hydrogen Ion Intercalation
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Yuqian Wang, Guanghui Cai, Zhanfen Chen, Huining Peng, Qinghua Zhang, Lei Gao, Mingtong Zhu, Xiangyu Lyu, Chao Lu, Jin Liu, Mengcheng Li, Keyue Liang, Pengyu Liu, Lu Wang, Huayu Tao, Jiayi Song, Qiang Wang, Ailing Ji, Miao Liu, Chaorong Li, Lin Gu, Pu Yu, Zexian Cao, and Nianpeng Lu
- Subjects
hydrogen ion intercalation ,insulator‐to‐metal transition ,ionic liquid gating ,TiO2 thin film ,transparent conducting properties ,Electric apparatus and materials. Electric circuits. Electric networks ,TK452-454.4 ,Physics ,QC1-999 - Abstract
Abstract Realizing transformation from transparent insulating to transparent conducting, is a pursuing goal in designing and fabricating novel optoelectronic materials and devices. Here, a pronounced insulating to metal transition in anatase TiO2 thin films is achieved through ionic liquid gating, and interestingly the material maintains an invariable high optical transparency. It is revealed that the emergent metallic state can be attributed to the electron doping associated with the hydrogen ion intercalation. Importantly, the hydrogenation leads to the almost rigid shift of the Fermi energy and therefore maintains nicely the transparency at the visible light region. This result is in strong contrast with the case of oxygen vacancy doping, in which the optical bandgap is suppressed due to improved orbitals hybridization and intraband transition. Moreover, through synergistic ion‐electron doping, the selective control of the gating area and pattern is realized in the micrometer or even nanometer scale with extremely distinct physical properties, which can be employed to fabricate novel optical and electronic devices. The result greatly deepens the understanding of the underlying physics and formation mechanism of transparent conducting oxide (TCO) materials. It is envisioned that this work would provide a new pathway to design other potential optoelectronic materials with novel functionalities.
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- 2024
- Full Text
- View/download PDF
187. Influence of Surface Polarity on Catalytic Properties of Aminopyridine Functionalized Polyacrylonitrile Fiber Catalyst
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Weihua Chen, Ke Gao, Liwei Mi, Pengyu Li, Minli Tao, and Yu Yang
- Subjects
inorganic chemicals ,010405 organic chemistry ,organic chemicals ,Polyacrylonitrile ,Infrared spectroscopy ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Pyridine ,heterocyclic compounds ,Fiber ,Methanol ,Fourier transform infrared spectroscopy ,Selectivity - Abstract
This work has been developed to study the effect of fiber catalyst surface polarity on catalyst performance. Taking 4-dimethyl amine pyridine (DMAP) derivative functionalized polyacrylonitrile fiber catalyst (PANDMAPF) as the template catalyst, its surface property was adjusted through the introduction of phenyl and hydroxyl groups on PANDMAPF. Elemental analysis (EA), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and mechanical strength test are used to characterize and demonstrate the successful synthesis of different fiber catalysts. The catalytic performance of different fiber catalysts was tested by the reaction of one-pot three-component synthesis 2-amino-2-chromenes. The results showed that reducing the surface polarity of the catalyst could not only improve the activity of the catalyst, but also make the three-component reaction which could only be carried out in high polar solvents (water and methanol), but also proceed effectively in lower polar solvents (such as ethanol and n-butanol). Therefore, the activity and selectivity of the catalyst can be effectively regulated by introducing different polar auxiliary functional groups on the surface of the fiber catalyst, which provides a theoretical basis for the design and synthesis of high activity and selectivity fiber catalyst.
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- 2020
188. Bifunctionalized polyacrylonitrile fibers as highly efficient and selective heterogeneous catalysts for cycloaddition of CO2 with epichlorohydrin under mild conditions
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Pengyu Li, Liwei Mi, Jianliang Cao, Wenqin Zhang, Xian-Lei Shi, Peigao Duan, and Yuanyuan Liu
- Subjects
Polyacrylonitrile ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,Cycloaddition ,0104 chemical sciences ,chemistry.chemical_compound ,Benzylamine ,chemistry ,Polar effect ,Organic chemistry ,Epichlorohydrin ,Fiber ,0210 nano-technology ,Bifunctional - Abstract
Converting CO2 into useful chemical materials has uniquely high value in both chemical and resource-oriented sense. In this work, several kinds of bifunctional polyacrylonitrile fiber catalysts were developed and applied to selectively catalyze the fixing of CO2 with epichlorohydrin. Compared to the synergistic effect, the surface polar effect is the major influence factor for the catalytic activity of the fiber catalyst, which is different from other support catalysts and has been explained detailly in this work. Among the synthesized fiber catalysts, benzylamine and N,N’-dimethyl-N-(4-pyridyl)-1,3-propanediamine (DA) bifunctionalized fiber (PANBDF) has excellent high catalytic activity for its lower polar microenvironment. Different PANBDFs with various benzylamine and DA modified degrees were prepared to inspect the influences of benzylamine and DA amounts on the catalytic activity. PANBDF (benzylamine and DA modified degrees are 0.93 mmol/g and 0.16 mmol/g, respectively) can complete the reaction of epichlorohydrin and CO2 (97% conversion) under 0.1 mol% catalyst dosage at 80 °C with a CO2 balloon. Under very low catalyst amount (0.0125 mol%), it can also effectively catalyze the reaction with 56% conversion and the TOF reaches up to 9333.3 h−1. Furthermore, the fiber catalyst can be reused at least five times which indicates a potential to value-added chemistry.
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- 2020
189. Effective regeneration of scrapped LiFePO4 material from spent lithium-ion batteries
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Jing Li, Pengyu Li, Yifei Ren, Rui Wang, Xin Tang, and Jidong Duan
- Subjects
Materials science ,Annealing (metallurgy) ,Mechanical Engineering ,Hydrothermal treatment ,Hydrothermal circulation ,Ion ,law.invention ,Crystallinity ,Chemical engineering ,Mechanics of Materials ,law ,Impurity ,General Materials Science ,Calcination ,Leaching (metallurgy) - Abstract
Since LiFePO4 has few other valuable metals except lithium, there are no economic advantages in recovery of scrapped LiFePO4 by leaching. Therefore, regeneration of scrapped LiFePO4 is the most reasonable choice. Based on the study of the main cause of the capacity fading of LiFePO4 (the loss of lithium), traditional regeneration method (solid-phase calcination) and a new process (hydrothermal treatment followed by annealing) are both applied to replenish lithium ions in this work. Compared with solid-phase calcination, hydrothermal treatment can not only make the lithium replenishment more uniform and make the particles have better morphology, but also avoid the side reactions to reduce the formation of impurities. In hydrothermal reaction, the solution dissolves only LiOH and Na2SO3. So the waste liquid is easily disposed of and it can’t trigger environmental secondary pollution. In addition, hydrothermal re-lithiation does not require tedious calculation of the amount of lithium to be added. The subsequent annealing can improve the crystallinity, improving the initial and rate capacity. The LiFePO4 regenerated by solid-phase calcination regained the initial capacity of 135.13 mAh g−1. After hydrothermal reaction at suitable temperatures (150 and 180 °C) followed by annealing, the initial capacity can increase to 144.02 and 141.81 mAh g−1, respectively.
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- 2020
190. Remediation of hexachlorobenzene‐contaminated soils with alkyl glycoside‐enhanced desorption and zero‐valent iron–EDTA–air treatment
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Wang Di, Haiyan Zhou, Xiaohua Lu, Jing Chen, Menghua Cao, Pengyu Li, and Linling Wang
- Subjects
Environmental Engineering ,Environmental remediation ,Iron ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Dispersion (geology) ,complex mixtures ,01 natural sciences ,Soil ,chemistry.chemical_compound ,Desorption ,Air treatment ,Hexachlorobenzene ,Soil Pollutants ,Glycosides ,Waste Management and Disposal ,Edetic Acid ,Environmental Restoration and Remediation ,Alkyl ,0105 earth and related environmental sciences ,Water Science and Technology ,chemistry.chemical_classification ,Zerovalent iron ,04 agricultural and veterinary sciences ,Pollution ,chemistry ,Critical micelle concentration ,Environmental chemistry ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries - Abstract
In this work, the use of a coupled process, alkyl glycoside (APG) enhanced soil desorption followed by the zero-valent iron-ethylenediaminetetraacetic acid (EDTA)-air (ZEA) Fenton-like system, was investigated for the remediation of a simulated hexachlorobenzene (HCB)-contaminated diatomite soil and a real HCB-contaminated soil. Three surfactants with different concentrations were studied to obtain the suitable soil desorption agent. Compared with APG0810 and Triton x-100, APG0814 showed a better solubilization effect due to its lower critical micelle concentration. With addition of 3000 mg L-1 APG0814, 35% of HCB was removed from contaminated diatomite soil, and a small amount of residual APG in diatomite soil was found to be beneficial for the soil dispersion. After treatment with the ZEA system, the removal efficiency of HCB in the diatomite soil desorption solution reached 76% in 2 h; we observed that a small amount of APG retained in the desorption solution accelerated the HCB removal. A real HCB-contaminated soil was used to verify the remediation effects. This study demonstrates that our approach is a feasible alternative for remediating soil contaminated with hydrophobic organic compounds.
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- 2020
191. Activity of Sodium Lauryl Sulfate, Rhamnolipids, and N-Acetylcysteine Against Biofilms of Five Common Pathogens
- Author
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Xiaonan Chen, Yuanna Shen, Haiyan Hu, Yiqing Zou, Gang Yuan, Pengyu Li, and Huatian Li
- Subjects
Microbiology (medical) ,Sodium ,Immunology ,chemistry.chemical_element ,macromolecular substances ,medicine.disease_cause ,Microbiology ,Acetylcysteine ,03 medical and health sciences ,medicine ,Escherichia coli ,030304 developmental biology ,Pharmacology ,0303 health sciences ,biology ,030306 microbiology ,Chemistry ,Pseudomonas aeruginosa ,fungi ,Biofilm ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Streptococcus mutans ,Staphylococcus aureus ,Bacteria ,medicine.drug - Abstract
Bacteria in biofilms are more resistant to antibacterial agents than bacteria in planktonic form. Hence, antibacterial agents should be able to eradicate biofilms to ensure the best outcomes. Littl...
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- 2020
192. AIEgen based polymorphs with solvent regulated crystal-to-crystal switch properties
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Wenyu Cheng, Bing Fang, Meizhen Yin, Pengyu Li, Liming Lai, and Yantu Zhang
- Subjects
Materials science ,Photochemistry ,Evaporation (deposition) ,Fluorescence ,Solvent ,Crystal ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Molecular stacking ,Molecule ,General Materials Science ,Single crystal ,Dichloromethane - Abstract
Organic polymorphic materials have attracted considerable interest in recent years owing to their unique photophysical properties and application potential in fluorescent sensors and information storage. However, the preparation of organic polymorphs with crystal-to-crystal switch properties remains challenging, which hampers understanding the relationship between molecular stacking and emission properties. Herein, an AIEgen with tunable polymorphism-dependent emission and solvent regulated crystal-to-crystal switch properties is reported. Two polymorphs, an orange crystal (OC) and a red crystal (RC), of the AIEgen with different emission were obtained by slow evaporation in cultivation solvents (dichloromethane (DCM)/n-hexane) with different compositions. The polymorphs can be reversibly switched when exposed to different solvent vapors. Further investigation of the single crystal structures suggests that the molecular stacking mode of the crystal plays an important role in the emission properties. The real-time in situ monitoring of the polymorphs with fluorescence spectra and micrographs when exposed to solvent vapor reveals that the capture/release of DCM molecules induces molecular re-arrangements, and thus causes the switch. Such a conclusion is further supported by thermal recovery experiments. Our study on the crystal-to-crystal switch properties of AIEgen based polymorphs has provided insight into the relationship between molecular stacking and emission properties.
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- 2020
193. Highly fluorescent free-standing films assembled from perylenediimide microcrystals for boosting aniline sensing
- Author
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Pengfei Li, Klaus Müllen, Pengyu Li, Baozhong Lü, Yantu Zhang, and Meizhen Yin
- Subjects
Materials science ,Chemical substance ,Fabrication ,Nanotechnology ,General Chemistry ,Fluorescence ,Photoinduced electron transfer ,chemistry.chemical_compound ,Aniline ,chemistry ,Materials Chemistry ,Molecule ,Density functional theory ,Science, technology and society - Abstract
Molecular assembly has emerged as a key protocol for designing functional materials, although building in task-specific applications remains challenging. Here, a simple solvent-diffusion fabrication of highly fluorescent free-standing films (FFSFs) obtained from perylenediimide (PDI) microcrystals is described. The high fluorescence intensity of the resulting FFSFs follows from the mode of solid-state packing of the PDI molecules. The porous, crystalline FFSFs provide increased surface area and enable unobstructed diffusion of guest molecules for boosting aniline sensing with low detection limit, high selectivity and reversibility. Density functional theory (DFT) calculations indicate that the fluorescence quenching is caused by photoinduced electron transfer (PET). The new FFSFs furnish amplified discrimination of analytes and represent a major step ahead toward the rational synthesis of assembled sensing materials.
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- 2020
194. A Hybrid Control Strategy of Hybrid-Excitation Switched Reluctance Motor for Torque Ripple Reduction and Constant Power Extension
- Author
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Guoji Liu, Pengyu Li, and Wen Ding
- Subjects
Vector control ,Computer science ,020208 electrical & electronic engineering ,02 engineering and technology ,Thermal conduction ,Square (algebra) ,Switched reluctance motor ,Power (physics) ,Reduction (complexity) ,Control and Systems Engineering ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Torque ,Torque ripple ,Electrical and Electronic Engineering ,Excitation - Abstract
A novel hybrid control strategy combining vector control and current continuous conduction is proposed in this paper to improve the performance of a hybrid-excitation switched reluctance motor (HESRM). Vector control, widely used in ac machines, is redefined in HESRM based on static torque characteristic to simplify an HESRM controller and reduce torque ripple. However, at a high-speed and heavy-load operation, current tracking accuracy deteriorates and torque ripple reduction effect gets worse. Current continuous conduction is combined with vector control to improve current tracking accuracy and maintain smooth torque ripple. In the HESRM, the power generally falls nearly in proportion to the square of speed over based speed, and a traditional control technique can maintain only a narrow constant power range. This novel vector control is easy to achieve phase advance and current continuous conduction simultaneously. By combining these two together, the HESRM can extend the constant power in a wider speed range and efficiency is also improved. Simulations and experiments in different conditions are carried out to verify the effectiveness of a hybrid control strategy.
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- 2020
195. Synergistic catalysis of bifunctional polyacrylonitrile fiber for the synthesis of (E)-α,β-unsaturated esters from aldehydes by decarboxylative Doebner–Knoevenagel reaction
- Author
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Liwei Mi, Xian-Lei Shi, Yuanyuan Liu, Pengyu Li, and Wenqin Zhang
- Subjects
General Chemical Engineering ,Polyacrylonitrile ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Solvent ,chemistry.chemical_compound ,chemistry ,Moiety ,Organic chemistry ,Knoevenagel condensation ,Synergistic catalysis ,Fiber ,0210 nano-technology ,Bifunctional - Abstract
A series of monofunctional and bifunctional polyacrylonitrile fiber catalysts have been successfully prepared to catalyze the decarboxylative Doebner–Knoevenagel reaction of aldehydes and monoethyl malonate for the syntheses of the (E)-α,β-unsaturated esters. Among which, the catalyst PANPDFII/I shows the best synergistic catalytic activity with high yields (89–96%), stereoselectivities (Z:E > 99:1) and reusability (up to 8 times). The influences of the N position on aminopyridine moiety, solvent and temperature on the catalytic system were investigated in detail. This catalytic system can process well in higher or lower polar organic solvents instead of moderate polar solvents, which is an interesting phenomenon in organic catalysis, and the reasons are explained in this work. Furthermore, a DMAP (4-dimethylaminopyridine) and piperazine synergistic catalytic mechanism in the micro-environment of the fiber catalyst has been conceived to explain the high catalytic performance of this catalytic system. Besides, the fiber catalyst PANPDFII/I shows high application potential in industry for its good performance in scaled-up experiment, as well as its advantages of the easy preparation, high mechanical strength, flexibility and high stability in air.
- Published
- 2020
196. Recyclable polyetheretherketone fiber-supported N-heterocyclic carbene catalysts for nucleophilic acylation of fluorobenzenes
- Author
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Kun Liu, Xian-Lei Shi, Pengyu Li, Qianqian Hu, Juanjuan Wang, and Benyu Sun
- Subjects
Chemistry ,Metals and Alloys ,General Chemistry ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Acylation ,Fluorobenzenes ,chemistry.chemical_compound ,Nucleophile ,Tweezers ,Polymer chemistry ,Materials Chemistry ,Ceramics and Composites ,Fiber ,Carbene - Abstract
We report for the first time a novel support of polyetheretherketone fiber for the synthesis of recyclable N-heterocyclic carbene (NHC) catalysts. The fiber catalysts were verified in nucleophilic acylation of fluorobenzenes with superior catalytic activities, and successfully recycled by a tiny pair of tweezers over 21 cycles with minimal loss of performance.
- Published
- 2020
197. Hypoxia-sensitive adjuvant loaded liposomes enhance the antimicrobial activity of azithromycin via phospholipase-triggered releasing for Pseudomonas aeruginosa biofilms eradication
- Author
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Yiqin Rao, Yingying Sun, Pengyu Li, Mao Xu, Xiaonan Chen, Yalong Wang, Yan Chen, Xin Deng, Shihui Yu, and Haiyan Hu
- Subjects
Lipopolysaccharides ,Phospholipases ,Biofilms ,Liposomes ,Pseudomonas aeruginosa ,Pharmaceutical Science ,Humans ,Pseudomonas Infections ,Microbial Sensitivity Tests ,Azithromycin ,Hypoxia ,Anti-Bacterial Agents - Abstract
Robust biofilms and the complex airway environment with thick sputum, local hypoxia and persistent inflammation induce the intractability of chronic pulmonary infections caused by Pseudomonas aeruginosa (P. aeruginosa). Herein, we proposed a type of antibiotic-adjuvant liposomes (NANO@PS-LPs), co-incorporating azithromycin (AZI), adjuvant (2-nitroimidazole derivative, 6-NIH) and biofilm dispersant (nitric oxide donor, DETA NONOate). NANO@PS-LPs possessing negatively-charged surface and good hydrophilicity could easily penetrate through the sputum layer, then disassembled triggered by overexpressed phospholipase A
- Published
- 2022
198. Antibiotics-free nanoparticles eradicate Helicobacter pylori biofilms and intracellular bacteria
- Author
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Yiqing Zou, Xiaonan Chen, Yingying Sun, Pengyu Li, Mao Xu, Pengchao Fang, Shuqi Zhang, Gang Yuan, Xin Deng, and Haiyan Hu
- Subjects
Linoleic Acid ,Helicobacter pylori ,Biofilms ,Pharmaceutical Science ,Humans ,Nanoparticles ,Urease ,Anti-Bacterial Agents ,Helicobacter Infections - Abstract
Biofilms and intracellular survival tremendously help Helicobacter pylori (H. pylori) escape from antibacterial agents attacking, therefore issuing extreme challenges to clinical therapies. Herein, we constructed fucoidan (FU)-coated nanoparticles (FU/ML-LA/EB NPs) via simple self-assembly of biguanide derivative (metformin-linoleic acid, ML) and linoleic acid (LA), encapsulating urease inhibitor ebselen (EB) instead of antibiotics to take antibacterial effect. Negatively charged FU/ML-LA/EB NPs easily penetrated through the gastric mucus layer to arrive at infection sites, then eradicated extracellular polymeric substances (EPS) to destroy H. pylori biofilms structure. After strengthening bacterial membrane permeability, the nanoparticles could enter H. pylori and kill bacteria by inhibiting the activity of urease. FU/ML-LA/EB NPs also entered H. pylori-infected host cells through receptor-mediated internalization, in which they activated AMPK to recover lysosomal acidification for killing intracellular H. pylori. Additionally, FU/ML-LA/EB NPs alleviated oxidative stress, hence reducing gastric mucosal damage and cutting off the pathways of carcinogenesis. Notably, H. pylori burden after FU/ML-LA/EB NPs treatment was reduced to a great extent in vivo, which was significantly lower than that after treatment with clinical therapy. Antibiotics-free FU/ML-LA/EB NPs improving bacterial eradication and alleviating oxidation stress made it a powerful approach against H. pylori.
- Published
- 2022
199. The Influence of Background Music on the Communication Effect of Mainstream Media’s Short Videos on Douyin
- Author
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Pengyu Li and Menglei Wu
- Published
- 2022
200. Analysis of Legal Documents via Non-negative Matrix Factorization Methods
- Author
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Pengyu Li, Ryan Budahazy, Lu Cheng, Yihuan Huang, Andrew Johnson, Joshua Vendrow, and Zhoutong Wu
- Published
- 2022
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