961 results on '"lei, Pei"'
Search Results
202. <scp>Carbon‐nanotube‐loaded</scp> planar gas and humidity sensor
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Yajun Liu, Lei Pei, Reyhan Baktur, and Wenping Ge
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Patch antenna ,Materials science ,Planar ,law ,Humidity ,Carbon nanotube ,Passive detection ,Electrical and Electronic Engineering ,Composite material ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention - Published
- 2020
203. Nitrogen and sulfur dual-doped high-surface-area hollow carbon nanospheres for efficient CO2 reduction
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Yu Wu, Yongjie Qin, Qi Hu, Jianhong Liu, Chuanxin He, Lei Pei, Qianling Zhang, Hengpan Yang, and Guodong Li
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Materials science ,chemistry.chemical_element ,02 engineering and technology ,General Medicine ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Gibbs free energy ,Catalysis ,symbols.namesake ,chemistry ,Chemical engineering ,Specific surface area ,symbols ,0210 nano-technology ,Selectivity ,Pyrolysis ,Carbon ,Faraday efficiency - Abstract
The electrochemical reduction of CO2 (CO2RR) can substantially contribute to the production of useful chemicals and reduction of global CO2 emissions. Herein, we presented N and S dual-doped high-surface-area carbon materials (SZ-HCN) as CO2RR catalysts. N and S were doped by one-step pyrolysis of a N-containing polymer and S powder. ZnCl2 was applied as a volatile porogen to prepare porous SZ-HCN. SZ-HCN with a high specific surface area (1510 m2 g−g1) exhibited efficient electrocatalytic activity and selectivity for CO2RR. Electrochemical measurements demonstrated that SZ-HCN showed excellent catalytic performance for CO2-to-CO reduction with a high CO Faradaic efficiency (~93%) at −0.6 V. Furthermore, SZ-HCN offered a stable current density and high CO selectivity over at least 20 h continuous operation, revealing remarkable electrocatalytic durability. The experimental results and density functional theory calculations indicated that N and S dual-doped carbon materials required lower Gibbs free energy to form the COOH* intermediate than that for single-N-doped carbon for CO2-to-CO reduction, thereby enhancing CO2RR activity.
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- 2020
204. Mechanistic investigation of cellular internalization routes of polymeric particles on breast cancer cells: relevance for drug delivery applications
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Jie Chen, Mei-rong Zhou, Lei Pei, Pingfang Xie, Feng Xu, Jia Gong, and Yu-Fang Wu
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Chemistry ,Materials Science (miscellaneous) ,Pinocytosis ,media_common.quotation_subject ,02 engineering and technology ,Cell Biology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Endocytosis ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Live cell imaging ,Drug delivery ,Biophysics ,Viability assay ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,Cytotoxicity ,Internalization ,Intracellular ,Biotechnology ,media_common - Abstract
The tuning of physicochemical properties like particle sizes, surface modifications, etc., is essential to improve delivery efficiency with insignificant toxicity. A quantitative and mechanistic investigation on cellular uptake and intracellular trafficking of fluorescent-labeled polystyrene particles [50 and 500 nm plain and 200 nm and 1 µm carboxylate-coated polystyrene (PPS and CPS)] against breast cancer cells was performed. Examinations of cell proliferation, viability, and cytotoxicity indicated that those applied polymeric particles at concentrations of 4–40 µg/mL are non-toxic to cells except 200 nm CPS (16 µg/mL) which partially reduced cell viability. Quantitative fluorescent microscopy revealed that 200 nm CPS displayed the highest capability to be internalized by MCF-7 cells, in which the average intracellular particles are about 14 and 35 folds higher than 1 µm CPS and 500 nm PPS, respectively. Analysis of the uptake routes using inhibitors provided clear evidence that 200 CPS was mainly ingested via the clathrin-mediated endocytosis, whereas larger particles (> 500 nm) preferentially utilized the macropinocytosis pathway. Fluorescent live-cell imaging suggested that particles were mainly internalized by cells in an individual form instead of large aggregates, despite late occurrence of partial agglomeration in the cytoplasm. Overall, those outcomes enhanced our understanding of the application of polymeric delivery vehicles for the treatment of breast cancer.
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- 2020
205. Claudin-2 deficiency associates with hypercalciuria in mice and human kidney stone disease
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Joshua N. Curry, Koichi Matsuda, Mehdi Totonchi, Michael B. Filla, Masomeh Askari, Lei Pei, Timothy A. Fields, Chizu Tanikawa, Matthew Saurette, Andrew P. Evan, Peter S. N. Rowe, Megan R Beggs, Andre J. Sommer, Yoichiro Kamatani, Alan S.L. Yu, and R. Todd Alexander
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0301 basic medicine ,Nephrology ,medicine.medical_specialty ,endocrine system diseases ,Urology ,Hypercalciuria ,chemistry.chemical_element ,Calcium ,urologic and male genital diseases ,Gastroenterology ,Kidney Tubules, Proximal ,Kidney Calculi ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Humans ,Animals ,Claudin-2 ,Claudin ,Stone disease ,Mice, Knockout ,Calcium metabolism ,urogenital system ,Reabsorption ,business.industry ,Genetic Variation ,Human kidney ,General Medicine ,medicine.disease ,female genital diseases and pregnancy complications ,030104 developmental biology ,Endocrinology ,Gene Expression Regulation ,chemistry ,Kidney stone disease ,030220 oncology & carcinogenesis ,Claudins ,Kidney stones ,Nephrocalcinosis ,business ,Research Article - Abstract
The major risk factor for kidney stone disease is idiopathic hypercalciuria. Recent evidence implicates a role for defective calcium reabsorption in the renal proximal tubule. We hypothesized that claudin-2, a paracellular cation channel protein, mediates proximal tubule calcium reabsorption. We found that claudin-2–null mice have hypercalciuria due to a primary defect in renal tubule calcium transport and papillary nephrocalcinosis that resembles the intratubular plugs in kidney stone formers. Our findings suggest that a proximal tubule defect in calcium reabsorption predisposes to papillary calcification, providing support for the vas washdown hypothesis. Claudin-2–null mice were also found to have increased net intestinal calcium absorption, but reduced paracellular calcium permeability in the colon, suggesting that this was due to reduced intestinal calcium secretion. Common genetic variants in the claudin-2 gene were associated with decreased tissue expression of claudin-2 and increased risk of kidney stones in 2 large population-based studies. Finally, we describe a family in which males with a rare missense variant in claudin-2 have marked hypercalciuria and kidney stone disease. Our findings indicate that claudin-2 is a key regulator of calcium excretion and a potential target for therapies to prevent kidney stones.
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- 2020
206. Surface Parameter Measurement of Braided Composite Preform Based on Faster R-CNN
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Lei Geng, Ying Sun, Fang Zhang, Zhitao Xiao, Lei Pei, and Wu Jun
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Surface (mathematics) ,Materials science ,Polymers and Plastics ,Braided composite ,business.industry ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Measure (mathematics) ,0104 chemical sciences ,Image database ,Computer Science::Computer Vision and Pattern Recognition ,Computer vision ,Artificial intelligence ,0210 nano-technology ,Pitch length ,business - Abstract
Pitch length and surface braiding angle are two important parameters of braided composite preforms. In this paper, a method based on Faster R-CNN is proposed to measure the two parameters. First, after image acquisition, a fabric image database including initial cropped images, augmented images, and target images is established. Then, the target images are classified into four categories according to the gray change characteristics. Third, a Faster R-CNN fabric detection model is trained on the fabric image database. Fourth, targets are detected by the trained network, and corners are detected based on the detected targets. Finally, pitch lengths and surface braiding angles are measured based on the detected corners. Experimental results show that the proposed method achieves the automatic measurement of pitch lengths and surface braiding angles of 2D and 3D braided composite preforms with high accuracy.
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- 2020
207. Size-segregated Characteristics and Formation Mechanisms of Water-soluble Inorganic Ions during Different Seasons in Heshan of Guangdong, China
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Peng Cheng, Ridong Cai, Duohong Chen, Bo Huang, Cheng-Lei Pei, Mei Li, Ting Gan, Zhong Fu, Wei Gao, Zhen Zhou, Lei Li, Yu-Jun Wang, and Zhengxu Huang
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inorganic chemicals ,Aqueous solution ,food.ingredient ,Chemistry ,Sea salt ,chemistry.chemical_element ,Inorganic ions ,Pollution ,Sulfur ,Nitrogen ,Aerosol ,food ,Environmental chemistry ,Environmental Chemistry ,Particle ,Particle size - Abstract
To identify the characteristics, sources, and formation mechanisms of aerosol particles during pollution episodes in the Pearl River Delta, 24 sets of size-segregated samples were collected in Heshan during July 2014 and January 2015 using a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI), and nine ions, viz., Na+, NH4+, K+, Mg2+, Ca2+, Cl–, NO2–, NO3–, and SO42–, were investigated. The Na+, Mg2+, and Ca2+ were mainly distributed in the coarse particles, and were mainly from soil, dust, and sea salt. The fine-mode K+ during winter was mostly generated by biomass burning. The coarse-mode Cl– originated from sea salt, whereas the fine-mode Cl– resulted from the conversion of NH4Cl to the particle phase. Both the SO42– and the NO3– exhibited unimodal distributions during winter but bimodal ones during summer. The coarse-mode SO42– and NO3– arose from sea salt and heterogeneous reactions, respectively. An increase in the nitrogen oxidation ratio (NOR) and a decrease in the sulfur oxidation ratio (SOR) were observed on polluted days, with the highest values occurring in the 0.56–1 µm particle size fraction. The formation of NO3– was chiefly related toµ homogeneous gas-phase reactions during winter and nocturnal heterogeneous reactions involving N2O5 during summer, whereas the formation of SO42– was driven by gas-phase oxidation in the 0.056–0.32 µm size range and aqueous oxidation in the 0.56–3.2 µm range. Additionally, the SOR and the NO2 concentration displayed a positive correlation in the 0.056–1.8 µm particle size fraction, indicating that the potential formation of SO42– via aqueous reactions was accelerated by NO2.
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- 2020
208. Surgery of the Primary Tumor Offers Survival Benefits of Breast Cancer with Synchronous Ipsilateral Supraclavicular Lymph Node Metastasis
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Lei Pei, Liyun Zeng, Dengjie Ouyang, Qiongyan Zou, Q. Chen, Na Luo, Wenjun Yi, and Piao Zhao
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Adult ,medicine.medical_specialty ,Population ,Breast Neoplasms ,030204 cardiovascular system & hematology ,Metastasis ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,medicine ,Humans ,Radical surgery ,education ,Aged ,Neoplasm Staging ,Retrospective Studies ,education.field_of_study ,business.industry ,Retrospective cohort study ,Middle Aged ,medicine.disease ,Primary tumor ,Supraclavicular lymph nodes ,Surgery ,medicine.anatomical_structure ,Lymphatic Metastasis ,030220 oncology & carcinogenesis ,Female ,business ,Abdominal surgery - Abstract
Background Controversy exists around the locoregional management of the primary tumor for breast cancer associated with synchronous ipsilateral supraclavicular lymph node metastasis (sISLM) due to the rarity of the disease and limited available data. This study aimed to compare outcomes of patients in the Surveillance, Epidemiology, and End Results (SEER) database with sISLM who underwent surgical resection and radiation of the primary tumor with those who did not. Methods This population-based retrospective study included breast cancer patients with sISLM without distant metastases from 2004 to 2016 in the SEER database. In this study, patients had been stratified by operative management, and propensity score matching (PSM) had been successfully applied. Results A total of 1172 breast cancer patients with sISLM were included in the study: 863 (73.6%) of patients underwent the primary tumor resection, and 309 (26.4%) patients did not undergo surgery. The median survival time in the surgery group was longer compared to the nonsurgery group in the overall cohort and the PSM cohort. We concluded that the primary tumor resection was associated with improved survival. Subgroup analysis further demonstrated that local surgery was not inferior to radical surgery. Conclusion For selected breast cancer patients with sISLM, surgery is a promising local intervention which may improve the survival.
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- 2019
209. A CMOS Electrochemical Biochip With 32$\times$ 32 Three-Electrode Voltammetry Pixels
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Robert G. Kuimelis, Yang Liu, Kae-Dyi You, Nicholas Wood, Arun Manickam, Davood Shahrjerdi, Arjang Hassibi, Nader Gamini, Mark W. McDermott, Ritu Raj Singh, and Lei Pei
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Materials science ,Dynamic range ,020208 electrical & electronic engineering ,Analytical chemistry ,02 engineering and technology ,Transducer ,CMOS ,Amorphous carbon ,Electrode ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Biochip ,Biosensor ,Voltammetry - Abstract
A CMOS-integrated electrochemical biochip for high-performance molecular testing is presented. The system includes an array of 32 $\times $ 32 three-electrode voltammetry pixels and on-chip temperature control between 25 and 95 °C. Each 100 $\mu \text{m}\,\times 100\,\,\mu \text{m}$ pixel includes a CMOS-compatible and chemo-stable amorphous carbon electrode transducer connected to in-pixel $\Sigma \Delta $ current detection circuitry with 280 fA rms input-referred noise (0.1–20 Hz bandwidth) and 93 dB dynamic range (DR). Array-based DNA detection assays are implemented, and successful DNA melt-analysis and real-time label-free DNA hybridization detection are reported.
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- 2019
210. Containment strategies for synthetic gene drive organisms and impacts on gene flow
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Markus Schmidt and Lei Pei
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Containment (computer programming) ,Synthetic gene ,Computational biology ,Biology ,Gene flow - Published
- 2021
211. Study on deformation and force of a super high arch dam during impoundment period in Southwest China
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Yuchen Fu, Yaosheng Tan, Yu Hu, Chunfeng Liu, Lei Pei, and Yajun Wang
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- 2021
212. Robot-assisted anterior transpedicular screw fixation with 3D printed implant for multiple cervical fractures: A case report
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Lei Pei, Wei Yuan, Xinchun Liu, Lin Cong, and Yue Zhu
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General Medicine - Published
- 2022
213. Growth and characterization of yttrium oxide films by reactive magnetron sputtering
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Zhu, Jiaqi, Zhu, Yuankun, Shen, Weixia, Wang, Yongjie, Han, Jiecai, Tian, Gui, Lei, Pei, and Dai, Bing
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- 2011
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214. Synergetic Design of Transparent Topcoats on ITO-Coated Plastic Substrate to Boost Surface Erosion Performance
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Zhang, Xuan, primary, Chen, Yuandong, additional, Zhang, Wenqiao, additional, Zhong, Yanli, additional, Lei, Pei, additional, Hao, Changshan, additional, and Yan, Yue, additional
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- 2021
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215. Automated Solving Algorithm and Application for Oriented Bounding Box Based on Principal Axis of Inertia
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Zhang, Wenguo, primary, Zhang, Le, additional, Lei, Pei, additional, and Jin, Xiaobo, additional
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- 2021
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216. Reliability Analysis on Domestic Special CNC Machine Tools Based on Weibull Distribution
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Shi, Zhanghu, primary, Zhao, Xi, additional, Zhang, Huang, additional, Sun, Hailong, additional, Zeng, Chao, additional, Lei, Pei, additional, He, Xiaoxu, additional, and Xia, Fengqin, additional
- Published
- 2021
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217. Relative contribution of rice and fish consumption to bioaccessibility-corrected health risks for urban residents in eastern China
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Wang, Wenqin, primary, Gong, Yu, additional, Greenfield, Ben K., additional, Nunes, Luís M., additional, Yang, Qianqi, additional, Lei, Pei, additional, Bu, Wenbo, additional, Wang, Bin, additional, Zhao, Xiaomiao, additional, Huang, Lei, additional, and Zhong, Huan, additional
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- 2021
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218. The silver linings of mercury: Reconsideration of its impacts on living organisms from a multi-timescale perspective
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Li, Chengjun, primary, Shen, Jun, additional, Zhang, Jin, additional, Lei, Pei, additional, Kong, Yaqi, additional, Zhang, Jichao, additional, Tang, Wenli, additional, Chen, Tianyu, additional, Xiang, Xin, additional, Wang, Shuxiao, additional, Zhang, Wei, additional, and Zhong, Huan, additional
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- 2021
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219. Rationally Tailoring Pore and Surface Properties of Metal-Organic Frameworks for Boosting Adsorption of Dy
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Lei, Pei, Xudong, Zhao, Baosheng, Liu, Zhengjie, Li, and Yinghui, Wei
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The adsorption and recovery of dysprosium ions (Dy
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- 2021
220. Metformin attenuates H2O2‑induced osteoblast apoptosis by regulating SIRT3 via the PI3K/AKT pathway
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Yue Zhu, Lin Tao, Lei Pei, Keda Yang, and Siming Zhou
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Cancer Research ,Gene knockdown ,SIRT3 ,Chemistry ,General Medicine ,Mitochondrion ,Pharmacology ,Metformin ,Immunology and Microbiology (miscellaneous) ,Apoptosis ,medicine ,Ovariectomized rat ,Viability assay ,PI3K/AKT/mTOR pathway ,medicine.drug - Abstract
Osteoporosis is a common metabolic disease that has a high incidence in postmenopausal women. Studies have indicated that oxidative damage plays an important role in the development of postmenopausal osteoporosis. Metformin has been showed to have the ability to relieve excessive oxidation. The aim of the present was to determine the therapeutic effect and potential mechanism of metformin in postmenopausal osteoporosis. Oxidative damage was stimulated in vitro by the addition of H2O2 to MC3T3-E1 cells and a mouse menopausal model was also constructed. Cell viability and flow cytometry experiments were performed to determine the effects of H2O2 and metformin treatment on apoptosis. Mitochondrial membrane potential was tested by JC-1 assays. Western blotting was used to detect the expression of mitochondrial apoptosis markers and antioxidant enzymes. Small interfering RNA was used to knockdown sirtuin3 (SIRT3), which was verified at the mRNA and protein levels. Bilateral ovariectomy was used to prepare menopausal mice, which were analyzed using micro-computed tomography. The results indicated that metformin is able to repair mitochondrial damage and inhibit the apoptosis of osteoblasts induced by H2O2, and also reverse bone mass loss in ovariectomized mice. Western blotting results demonstrated the involvement of SIRT3 in the production of antioxidant enzymes that are essential in protecting against mitochondrial injury. In addition, experiments with SIRT3 knockdown indicated that metformin reverses H2O2-induced osteoblast apoptosis by upregulating the expression of SIRT3 via the PI3K/AKT pathway. The results of the present reveal the pathogenesis of oxidative damage and the therapeutic effect of metformin in postmenopausal osteoporosis. They also suggest that SIRT3 is a potential drug target in the treatment of osteoporosis, with metformin being a candidate drug for modification and/or clinical application.
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- 2021
221. The mechanism of Annexin A1 to modulate TRPV1 and nociception in dorsal root ganglion neurons
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Dian Yu, You Shang, Yao Yi, Youming Lu, Yufen Zhang, Hongyan Yu, Xiao Ke, Lei Pei, Qiang Li, and Sehui Ma
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QH301-705.5 ,TRPV1 ,QD415-436 ,Pharmacology ,Biochemistry ,General Biochemistry, Genetics and Molecular Biology ,Formyl peptide receptor 2 ,chemistry.chemical_compound ,Formyl peptide receptor ,Dorsal root ganglion ,medicine ,Patch clamp ,Biology (General) ,Hot plate test ,Receptor ,Annexin A1 ,Neuronal sensitivity ,Chemistry ,Research ,Transient receptor potential vanilloid 1 ,medicine.anatomical_structure ,Nociception ,Capsaicin ,Nociceptive sensation ,TP248.13-248.65 ,Biotechnology - Abstract
Background Annexin A1 (ANXA1) exerts anti-nociceptive effect through ANXA1 receptor formyl peptide receptor 2 (FPR2/ALX (receptor for lipoxin A4), FPR2) at the dorsal root ganglia (DRG) level. However, the mechanisms remain elucidated. By using radiant heat, hot/cold plate, tail flick, von Frey, and Randall-Selitto tests to detect nociception in intact and chemical (capsaicin, menthol, mustard oil, formalin or CFA) injected AnxA1 conditional knockout (AnxA1−/−) mice, applying calcium imaging and patch clamp recordings in cultured DRG neurons to measure neuronal excitability, conducting immunofluorescence and western blotting to detect the protein levels of TRPV1, FPR2 and its downstream molecules, and performing double immunofluorescence and co-immunoprecipitation to investigate the interaction between Calmodulin (CaM) and TRPV1; we aim to uncover the molecular and cellular mechanisms of ANXA1’s role in antinociception. Results AnxA1−/− mice exhibited significant sensitivity to noxious heat (mean ± SD, 6.2 ± 1.0 s vs. 9.9 ± 1.6 s in Hargreaves test; 13.6 ± 1.5 s vs. 19.0 ± 1.9 s in hot plate test; n = 8; P vs. 76.2 ± 10.9; n = 8; P vs. 76.0 ± 21.9 s; n = 8; P vs. 320.4 ± 33.6 s; n = 8; P vs. 5.9 ± 1.4 s; n = 8; P 2+ response, TRPV1 currents and neuronal firing in AnxA1 deficient DRG neurons. Furthermore, ANXA1 mimic peptide Ac2-26 robustly increased intracellular Ca2+, inhibited TRPV1 current, activated PLCβ and promoted CaM-TRPV1 interaction. And these effects of Ac2-26 could be attenuated by FPR2 antagonist Boc2. Conclusions Selective deletion of AnxA1 in DRG neurons enhances TRPV1 sensitivity and deteriorates noxious heat or capsaicin induced nociception, while ANXA1 mimic peptide Ac2-26 desensitizes TRPV1 via FPR2 and the downstream PLCβ-Ca2+-CaM signal. This study may provide possible target for developing new analgesic drugs in inflammatory pain.
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- 2021
222. Categorization of Financial Transactions in QuickBooks
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Jocelyn Lu, Nhung Ho, Ying Sun, Juan Liu, Lei Pei, and Heather Simpson
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Categorization ,Computer science ,business.industry ,Deep learning ,Financial transaction ,Product (category theory) ,Artificial intelligence ,Recommender system ,Transfer of learning ,business ,Database transaction ,Data science ,Personalization - Abstract
This paper shares our work on building a machine learning system to categorize transactions for Intuit's QuickBooks product. Transaction categorization is challenging due to the complexity of accounting, the need for personalization, and the diversity of customers. We have broken down this monolithic problem into smaller pieces based on customers' life-cycle stages, and tailored solutions to address customer pain-points for each. Modern machine learning technologies such as deep neural networks, transfer learning, and few-shot learning are adopted to enable accurate transaction categorization. Furthermore our system learns user actions in real-time to provide relevant and in-time category recommendations. This in-session learning capability reduces user workload, improves customer experience, and helps to cultivate confidence.
- Published
- 2021
223. Multi-Scale Bidirectional Feature Fusion for One-Stage Oriented Object Detection in Aerial Images
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Gong Cheng, Qingyang Li, Xuxiang Sun, Lei Pei, Shicheng Miao, and Meili Zhang
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Basis (linear algebra) ,Scale (ratio) ,Minimum bounding box ,Computer science ,business.industry ,Feature extraction ,Context (language use) ,Computer vision ,Function (mathematics) ,Artificial intelligence ,Object (computer science) ,business ,Object detection - Abstract
This paper aims to address the problem of oriented object detection under the complex background of remote sensing images. To this end, we propose a one-stage object detection method with feature fusion structure, and modify the loss function to enhance the detection of small objects. More specifically, on the basis of the end-to-end one-stage object detection model RetinaNet, the method of gliding the vertices of the horizontal bounding box is used to describe an oriented object. In order to obtain multi-scale context information, we design a feature fusion module. Besides, we propose a novel area-weighted loss function to pay more attention to small objects. Experimental results conducted on the DOTA dataset demonstrate that the proposed framework outperforms several state-of-the-art baselines.
- Published
- 2021
224. The effect of Na0.44MnO2 formation in Na+-modified spinel LiMn2O4
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Xiong, Lilong, Xu, Youlong, Wu, Weiguo, Lei, Pei, Tao, Tao, and Dong, Xin
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- 2014
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225. The electrochemical performance of sodium-ion-modified spinel LiMn2O4 used for lithium-ion batteries
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Xiong, Lilong, Xu, Youlong, Lei, Pei, Tao, Tao, Dong, Xin, and Song, Jie
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- 2014
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226. Ecotoxicological effects of polyethylene microplastics and ZnO nanoparticles on earthworm Eisenia fetida
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Shuwu Zhang, Shan Ren, Lei Pei, Yuhuan Sun, and Fayuan Wang
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Ecology ,Soil Science ,Agricultural and Biological Sciences (miscellaneous) - Published
- 2022
227. Research Progress on the Growth of 4H-SiC Crystal by PVT Method and the Defect of Polytype Inclusions.
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WANG Yu, GU Peng, FU Jun, WANG Penggang, LEI Pei, and YUAN Li
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POWER semiconductors ,CRYSTAL growth ,HEAT resistant materials ,COREMAKING ,ELECTRIC breakdown ,SEMICONDUCTOR devices - Abstract
Silicon carbide (SiC), as a typical representative of the third-generation semiconductor material, has performance advantages in wide band gap, high thermal conductivity, high breakdown electric field and large electron drift velocity, etc., and is considered to be one of the ideal materials for high temperature, high frequency, high power and high voltage devices. SiC can effectively break through the physical limits of traditional Si-based power semiconductor devices, known as a green energy device that drives the "new energy revolution". As the core material for the manufacture of power devices, the growth of SiC single crystal substrate is very important, especially the preparation of single 4H-SiC polytype. Due to the better crystallographic compatibility and similar formation free energy among different polytypes, the grown SiC bulk crystals are prone to produce polytype inclusions and then seriously affect the device performance. Therefore, in this paper, the basic principle, growth process and existing problems of SiC crystal prepared by physical vapor transport (PVT) method are summarized firstly. Then the possible inducing factors for the formation of polytype inclusions were given and the relevant mechanisms are also discussed. In addition, the common identification methods of SiC polytype structures are further introduced. Finally, a prospect for the research of SiC single crystal are made. [ABSTRACT FROM AUTHOR]
- Published
- 2022
228. A shape-deformable liquid-metal-filled magnetorheological plastomer sensor with a magnetic field 'on-off' switch
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Lei Pei, Xinglong Gong, Jiaqi Xu, Haoming Pang, and Shouhu Xuan
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0301 basic medicine ,Multidisciplinary ,Materials science ,Science ,Magnetic property ,Insulator (electricity) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Plastomer ,Viscoelasticity ,Article ,Magnetic field ,03 medical and health sciences ,Coupling (physics) ,030104 developmental biology ,Electrical resistance and conductance ,Magnetorheological fluid ,Deformation (engineering) ,Composite material ,0210 nano-technology ,Nanomaterials ,Sensor - Abstract
Summary Flexible viscoelastic sensors have gained significant attention in wearable devices owing to their exceptional strain-dependent electrical resistance. Most of the strain sensors are elastic composites, thus the internal stress is often preserved during the deformation when they are attached to the uneven target. Therefore, there is a pressing need for viscoelastic composites with highly self-adapted electromechanical properties sensitive to multiexternal circumstances. This work reports a liquid-metal-filled magnetorheological plastomer (LMMRP) that shows a high response behavior to the external stimulus such as magnetic field, temperature, and force. The shape-deformable LMMRP can transform from an insulator to a conductor under applying a magnetic field, thus the further viscoelastic sensor possesses a magnetic field “on-off” switch effect. The microstructure-dependent magnetic/thermal/mechanical-electrical coupling characteristics are investigated, and several proof-of-concept sensor applications, such as magnetic control, environment recognition, and motion monitoring, are demonstrated. These LMMRP composites show a broad potential in flexible sensors and soft electronics., Graphical abstract, Highlights • A shape-deformable liquid-metal-filled magnetorheological plastomer was created. • The plastomer is sensitive to magnetic field, temperature, and force. • The evolution of the particle microstructure in the plastomer was simulated. • The plastomer has great potential in flexible electronics with magnetic control., Magnetic property; Nanomaterials; Sensor
- Published
- 2021
229. Further reuse of phosphorus-laden biochar for lead sorption from aqueous solution: Isotherm, kinetics, and mechanism
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Ling Zhao, Fan Yang, Lei Pei, Hongyan Nan, Xiaoyun Xu, Xinde Cao, and Xiangyang Gui
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Environmental Engineering ,Aqueous solution ,010504 meteorology & atmospheric sciences ,Precipitation (chemistry) ,Phosphorus ,Kinetics ,chemistry.chemical_element ,Sorption ,010501 environmental sciences ,01 natural sciences ,Pollution ,Adsorption ,chemistry ,Wastewater ,Lead ,Environmental chemistry ,Charcoal ,Biochar ,Environmental Chemistry ,Waste Management and Disposal ,0105 earth and related environmental sciences - Abstract
Biochar and engineered biochar have been used for phosphorous recovery from wastewater, but the resulted phosphorous-laden (P-laden) biochar needs further disposal. In this study, the feasibility of reusing P-laden biochar for Pb immobilization as well as the underlying mechanism was explored. Three types of engineered biochar, i.e., Ca modified biochar, Mg modified biochar, and Fe modified biochar, were selected to sorb P and then the exhausted biochar was further used for Pb sorption. Results showed that Mg and Ca modified biochar exhibited considerable Pb sorption capacity after P sorption with the maximum value of 3.36–4.03 mmol/g and 5.49–6.58 mmol/g, respectively, while P-laden Fe modified biochar failed to sorb Pb due to its acidic pH. The removal of Pb by P-laden Mg modified biochar involved more precipitation including PbHPO4, Pb5(PO4)3(OH), and Pb3(CO3)2(OH)2 because of its higher P sorption capacity and more -OH group on the surface. Cation exchange with CaCO3 to form PbCO3 was the main mechanism for Pb removal by P-laden Ca modified biochar despite the formation of Pb5(PO4)3(OH) precipitate. Our results demonstrate that waste P-laden biochar can be further used for the effective removal of Pb, which provides a potential approach for waste adsorbent disposal.
- Published
- 2021
230. Algal Organic Matter Drives Methanogen-Mediated Methylmercury Production in Water from Eutrophic Shallow Lakes
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Lei, Pei, primary, Zhang, Jin, additional, Zhu, Jinjie, additional, Tan, Qiaoguo, additional, Kwong, Raymond W. M., additional, Pan, Ke, additional, Jiang, Tao, additional, Naderi, Mohammad, additional, and Zhong, Huan, additional
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- 2021
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231. Pollution characteristics and ecological risks associated with heavy metals in the Fuyang river system in North China
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Zhao, Jiating, primary, Wu, Erwei, additional, Zhang, Bowen, additional, Bai, Xu, additional, Lei, Pei, additional, Qiao, Xiuwen, additional, Li, Yu-Feng, additional, Li, Bai, additional, Wu, Gang, additional, and Gao, Yuxi, additional
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- 2021
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232. Understanding the effects of sulfur input on mercury methylation in rice paddy soils
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Lei, Pei, primary, Tang, Chao, additional, Wang, Yongjie, additional, Wu, MengJie, additional, Kwong, Raymond W.M., additional, Jiang, Tao, additional, and Zhong, Huan, additional
- Published
- 2021
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233. Study on Formation Mechanism of Axle Part in the New Cross-Wedge Rolling Process Based on Experiment and Simulation
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Lei Pei, Xuedao Shu, and Chuan Liu
- Subjects
010302 applied physics ,business.product_category ,Materials science ,Computer simulation ,business.industry ,0211 other engineering and technologies ,02 engineering and technology ,Structural engineering ,01 natural sciences ,Wedge (mechanical device) ,Finite element method ,Axle ,0103 physical sciences ,Metallic materials ,business ,021102 mining & metallurgy - Abstract
Aiming at the concavity defects in the cross-wedge rolling (CWR) process, one new rolling method named as the twice closed–open joint CWR was presented to improve the use ratio of material in CWR of the axle parts. The new rolling method included three stages: the first closed rolling, the second closed rolling and the last open rolling. To investigate the flow of material in this rolling process, one 3D finite element model (FEM) of the twice closed–open joint CWR was established. The CWR process of one pump spindle part was simulated using the established 3D FEM. The formation, the flow law of metal materials and concavity defects of end were studied. In addition, the CWR experiments were carried out. The results of simulation agreed with the results of tests well. The results proved that the new method can decrease the extent of concavity and improve the material use ratio.
- Published
- 2019
234. Experiments and Simulations on the Magnetorheology of Magnetic Fluid Based on Fe3O4 Hollow Chains
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Shouhu Xuan, Xinglong Gong, Jie Wu, Linfeng Bai, and Lei Pei
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Materials science ,Field (physics) ,Magnetic dip ,02 engineering and technology ,Surfaces and Interfaces ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Hagen–Poiseuille equation ,01 natural sciences ,0104 chemical sciences ,Magnetic field ,Physics::Fluid Dynamics ,Condensed Matter::Materials Science ,Viscosity ,Rheology ,Magnetorheological fluid ,Electrochemistry ,Shear stress ,General Materials Science ,Composite material ,0210 nano-technology ,Spectroscopy - Abstract
This work reports an experiment/simulation combination study on the magnetorheological (MR) mechanism of magnetic fluid based on Fe3O4 hollow chains. The decrease of shear stress versus the increasing magnetic field was observed in a dilute magnetic fluid. Hollow chains exhibited a higher MR effect than pure Fe3O4 hollow nanospheres under a small magnetic field. A modified particle level simulation method including the translational and rotational motion of chains was developed to comprehend the correlation between rheological properties and microstructures. Sloping cluster-like microstructures were formed under a weak external field (24 mT), while vertical column-like microstructures were observed under a strong field (240 mT). The decrease of shear stress was due to the strong reconstruction process of microstructures and the agglomeration of chains near the boundaries. The chain morphology increased the dip angle of microstructures and thus improved the MR effect under a weak field. This advantage made Fe3O4 hollow chains to be widely applied for small and low-power devices in the biomedical field. Dimensionless viscosity as a function of the Mason number was collapsed onto linear master curves. Magnetic fluid in Poiseuille flow in a microfluidic channel was also observed and simulated. A qualitative and quantitative correspondence between simulations and experiments was obtained.
- Published
- 2019
235. Ab initio study of (FeCpVCp) @MoS2 NT — A one-dimensional bimetallic sandwich molecular wire (FeCpVCp) encapsulated into MoS2 nanotube
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Yangyang Hu, Lei Pei, Guiling Zhang, Yuxiu Wang, Zhao-Di Yang, Hong Yu, Ping Pan, and Cuicui Sun
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Molecular wire ,Spin states ,Spintronics ,Ferromagnetism ,Chemical physics ,Chemistry ,Ab initio ,General Physics and Astronomy ,Molecular electronics ,Density functional theory ,Electronic structure ,Physical and Theoretical Chemistry - Abstract
We present a theoretical study on a novel one-dimensional nanomaterial (FeCpVCp)n@MoS2 NT which are constructed with encapsulating organometallic sandwich molecular wires (FeCpVCp)n into armchair (8, 8) MoS2 NT, using density functional theory (DFT) and nonequilibrium Green’s function (NEGF) techniques. It is found that ferromagnetic (FeCpVCp)n@MoS2 NT is thermally stable with a high Curie or Neel temperature of 722.8 K. Transport property of (FeCpVCp)n@MoS2 NT is in good agreement with the electronic structure. (FeCpVCp)n offers a notable transport pathway along the axial direction, electron hopping may happen from (FeCpVCp)n to MoS2 NT sheath, which plays a significant role in electron transporting. Conductivity of (FeCpVCp)n@MoS2 NT is dependent on the spin states: spin-down state gives a higher conductivity than the spin-up state, opening out a spin-polarized transport property. These novel properties of (FeCpVCp)n@MoS2 NT render their potential applications in nanoscale spintronic and molecular electronics.
- Published
- 2019
236. The associations of air pollution exposure during pregnancy with fetal growth and anthropometric measurements at birth: a systematic review and meta-analysis
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Xiaojun Xu, Jiufeng Sun, Li Fu, Zuyao Yang, Sha Liu, Wenjun Ma, Xinyi Yang, Xing Li, Ganxiang Cao, Baixiang Feng, Yi Chen, Bo Zhang, Lei Pei, Xin Liu, Tao Liu, Yufeng Ye, and Hualiang Lin
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medicine.medical_specialty ,Health, Toxicology and Mutagenesis ,Air pollution exposure ,010501 environmental sciences ,01 natural sciences ,Fetal Development ,Pregnancy ,Negatively associated ,Air Pollution ,Included study ,Fetal growth ,medicine ,Humans ,Environmental Chemistry ,0105 earth and related environmental sciences ,Air Pollutants ,Obstetrics ,business.industry ,Infant, Newborn ,Environmental Exposure ,General Medicine ,Anthropometry ,medicine.disease ,Pollution ,Body Height ,Head circumference ,Maternal Exposure ,Meta-analysis ,Female ,business ,Head - Abstract
Fetal growth has been demonstrated to be an important predictor of perinatal and postnatal health. Although the effects of maternal exposure to air pollution during pregnancy on fetal growth have been investigated using ultrasound in many previous studies, the results were inconsistent and disputable. We aimed to qualitatively and quantitatively investigate the associations of air pollution exposure during different periods of pregnancy with fetal growth and anthropometric measurements at birth. We searched for all studies investigating the associations of air pollution exposure during pregnancy with fetal growth and birth anthropometric measurements in English and Chinese databases published before July 31, 2017. A random-effects model was employed in the meta-analysis to estimate the pooled effects of each 10 μg/m3 increment in air pollutant exposure. The ACROBAT-NRSI tool was applied to assess the quality of each included study, and the GRADE tool was employed to assess the overall quality of the meta-analysis. Maternal PM2.5 exposure (10 μg/m3) during the entire pregnancy was negatively associated with head circumference at birth (β = − 0.30 cm, 95% CI − 0.49, − 0.10), and NO2 exposure during the entire pregnancy was significantly linked to shorter length at birth (β = − 0.03 cm, 95% CI − 0.05, − 0.02). Maternal exposure to higher NO2 and PM2.5 during pregnancy may impair neonatal head circumference and length development, respectively. More studies are needed to confirm the effects of NO2 and PM2.5 and to identify the sources and major toxic components of PMs.
- Published
- 2019
237. Early Indosinian high-Mg# and high-Sr/Y ratio granodiorites in the Xiahe area, West Qinling, Central China: Petrogenesis and geodynamic implications
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Guochao Chen, Chengjun Liu, Ruibao Li, Feng Gao, Shao-Wei Zhao, Xianzhi Pei, Meng Wang, Zuochen Li, Youxin Chen, Xiaobing Li, and Lei Pei
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010504 meteorology & atmospheric sciences ,Continental crust ,Pluton ,Partial melting ,Geochemistry ,Geology ,Crust ,010502 geochemistry & geophysics ,01 natural sciences ,Geochemistry and Petrology ,Oceanic crust ,Mafic ,0105 earth and related environmental sciences ,Petrogenesis ,Zircon - Abstract
Indosinian granitic rocks are widespread in the West Qinling Orogen (WQO) in central China. Some of the early Indosinian granitoids have high Sr and low Y contents, and therefore high Sr/Y ratios, and they have been interpreted as adakitic rocks that formed by partial melting of thickened continental lower crust. However, several studies have revealed that granitoids with high Sr/Y ratios can be formed by various geological processes. Here, we report new zircon U-Pb ages, whole–rock geochemical data, and Sr–Nd–Hf isotope data for the Ganjiagongma pluton in the Xiahe area of the WQO, and we discuss whether the WQO underwent crustal thickening during the early Indosinian. The zircon U-Pb dating results indicate that the Ganjiagongma granodiorite and its mafic microgranular enclaves (MMEs) crystallized at ca 242 Ma. The MMEs are characterized by low SiO2 contents and Sr/Y ratios, and high MgO, Cr, and Ni contents, as well as high Mg# values, and they have evolved zircon Hf and whole–rock Sr-Nd isotopes, indicating they were produced by the partial melting of metasomatized continental lithospheric mantle. The granodiorite samples have some adakitic characteristics with SiO2 = 65.22 to 68.01 wt%, MgO = 1.07 to 1.71 wt%, Mg# = 59 to 62, Sr = 357 to 620 ppm, Y = 9.7 to 17.4 ppm, Sr/Y = 30.26 to 47.46, and no significant Eu anomalies. However, the granodiorites have relatively flat HREE patterns, indicating that amphibole, rather than garnet was the main residue in the source area, and this proposal is consistent with the relatively low but constant Nb/Ta values and varied Zr/Sm ratios. Simple two-end member modeling results indicate that the granodiorite could have been formed in normal or slightly thickened crust by mixing of 20%–30% mantle-derived melt with 70%–80% melt derived from the partial melting of basement rocks in the continental lower crust of the WQO. Taking into account other geological evidence, we propose that the formation of the Ganjiagongma pluton was related to the subduction of the A'nimaque-Mianlue oceanic crust, and that no significant thickening of the continental crust occurred in the WQO during the early Indosinian.
- Published
- 2019
238. Nicotinamide riboside protects against liver fibrosis induced by CCl4 via regulating the acetylation of Smads signaling pathway
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Yujia Zhou, Lei Pei, Lili Yang, Nengzhi Pang, Ting Wan, Yufeng Huang, Mingtong Ye, Rui Jiang, Xuye Jiang, Sufan Wang, Yuanling Huang, Hainan Yang, Zhenfeng Zhang, Wenhua Ling, Xufeng Li, and Yun Qiu
- Subjects
0301 basic medicine ,Gene knockdown ,CCL4 ,General Medicine ,Nicotinamide adenine dinucleotide ,030226 pharmacology & pharmacy ,General Biochemistry, Genetics and Molecular Biology ,In vitro ,Cell biology ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,0302 clinical medicine ,chemistry ,Nicotinamide riboside ,Hepatic stellate cell ,NAD+ kinase ,General Pharmacology, Toxicology and Pharmaceutics ,Signal transduction - Abstract
Aims Increasing nicotinamide adenine dinucleotide (NAD+) by Nicotinamide riboside (NR) provides protective benefits in multiple disorders. However, the role of NR on liver fibrosis is unclear. We performed in vivo and in vitro experiments to test the hepatic protective effects of NR against liver fibrosis and the underlying mechanisms. Materials and methods Mice were injected with CCl4 to establish liver fibrosis model. NR was given by gavage to explore the hepatic protection of NR. LX-2 cells were given a TGF-β stimulation ± NR, the activation of LX-2 cells and the acetylation of Smads were analyzed. To further confirm the role of Sirt1 on the protective pathway of NR, we knockdown Sirt1 in LX-2 cells. Key findings We found NR could prevent liver fibrosis and reverse the existing liver fibrosis. NR inhibited the activation of LX-2 cells induced by TGF-β, activated Sirt1 and deacetylated Smad2/3. Sirt1 knockdown diminished the inhibiting effect of NR on LX-2 cells activation, and increased expressions of acetylated Smads. In conclusion, NR could prevent liver fibrosis via suppressing activation of hepatic stellate cells (HSCs). This protective effect was mediated by regulating the acetylation of Smads signaling pathway. Significance NR protected mice against liver fibrosis induced by CCl4. NR suppressed activation of hepatic stellate cells induced by TGF-β. NR protects liver fibrosis via increasing the activity of Sirt1 and decreasing the expression of P300, resulting in the deacetylation of Smads in stellate cells.
- Published
- 2019
239. Recent progress on the simulation technology of magnetic fluid
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Lei Pei, Xinglong Gong, and Shouhu Xuan
- Subjects
Multidisciplinary ,Materials science ,business.industry ,Mechanics ,Computational fluid dynamics ,010502 geochemistry & geophysics ,01 natural sciences ,Magnetic field ,Dynamic simulation ,Surface coating ,Viscosity ,Magnetorheological fluid ,Magnetic nanoparticles ,Current (fluid) ,business ,0105 earth and related environmental sciences - Abstract
Magnetic fluid is a novel magnetorheological (MR) intelligent material consisting of magnetic particles, non-magnetic matrix, and additive agents. After applying the external magnetic field, magnetic particles will interact with each other due to the magnetic dipolar forces. The viscosity and yield stress of magnetic fluid could increase several orders of magnitude in milliseconds, which is called the MR effect. The controllable and reversible property makes magnetic fluid widely applied in drug targeting delivery, magnetic thermal therapy, commercial dampers, and polishing etc. In order to comprehend the mechanical behaviors of magnetic fluid, researchers developed several theoretical models for different flow conditions. However, due to the extensive calculation, theoretical models are only applicable for some special problems, such as 2-dimensional and axial symmetry. In recent years, with the development of computer performance, simulation has become an important method to investigate the MR mechanism of magnetic fluid. This paper reviews the recent progress in the theory and simulation of magnetic fluid. Firstly, theoretical models of magnetic fluid under shear mode, squeeze mode, and valve mode are introduced. Secondly, the existing simulation methods for magnetic fluid, such as molecular dynamics, particle-level dynamic simulation, and finite element method, are illustrated. The validity of the methods and their merits and drawbacks are discussed. Then, the research progress of the simulation of magnetic fluid is summarized from 3 aspects: Simulations of mechanical properties of novel magnetic fluid, simulations of complex mechanical behaviors of conventional magnetic fluid, and simulations of biomagnetic fluid. Finally, some future trends of simulation of magnetic fluid are proposed. The following 3 topics should be emphasized in the future work. First, a comprehensive theoretical model considering a variety of microscopic interactions is required. In order to prepare magnetic particles with high MR effect, excellent dispersibility, and low density, surface coating, modification, and additive agents are usually applied in experiments. Unfortunately, the influence of non-magnetic components on the MR effect is seldom considered in simulations. Second, current simulations could not simultaneously obtain the macroscopic mechanical properties and microstructures of magnetic fluid in complex flow. Finite element method and computational fluid dynamics are applicable for complex macroscopic problems but can not obtain the microstructures at the same time. Mesoscopic simulation methods can not exhibit large-scale aggregations of particles, which leads to the deviation compared with experiments. To establish multi-scale simulation methods and improve the accuracy of simulations have become an urgent requirement. Combining simulation methods with different spatial scales and reducing the time cost by using machine learning have become a possible approach. Third, multi-physics coupling simulation methods should be established. The magnetic field controlled electrical properties of magnetic fluid have attracted researchers interest in recent years. Magnetic fluid with this novel controllable property could be widely applied in battery and sensors. Investigations on other physical properties of magnetic fluid by using mechanical, electrical, and magnetic model together will be a future trend. These achievements will all contribute to the development of high-performance magnetic fluids and further enlarge the range of applications of magnetic fluid.
- Published
- 2019
240. Effect of ultrasonic vibration on ultra-precision diamond turning of Ti6Al4V
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Hongbing Wu and Lei Pei
- Subjects
0209 industrial biotechnology ,Materials science ,Mechanical Engineering ,Machinability ,Titanium alloy ,02 engineering and technology ,Diamond turning ,Industrial and Manufacturing Engineering ,Computer Science Applications ,Vibration ,020901 industrial engineering & automation ,Control and Systems Engineering ,Ultrasonic vibration ,Surface roughness ,Composite material ,Tool wear ,Software ,Surface integrity - Abstract
Because of the potential applications in the optical fields, the ultra-precision cutting of titanium alloys is attracting the interest of many researchers. Aimed at the problem of tool wear and poor surface quality in the ultra-precision cutting of titanium alloys, the method of ultrasonic vibration was used to assist the ultra-precision turning of titanium alloy for improving the machinability and better surface integrity. A lot of experiments of ultrasonic-assisted ultra-precision turning (UAUT) have been done to investigate the cutting phenomenon in UAUT of Ti6Al4V alloy. In addition, the effect of cutting parameters (amplitude of vibration, spindle speed, depth of cut and feeding speed) on the surface roughness, surface morphology, chip morphology and cutting force has been analyzed deeply. The results showed that the amplitude of ultrasonic vibration played the most important role in UAUT of Ti6Al4V alloy.
- Published
- 2019
241. Parameter Measurement of Biaxial Braided Composite Preform Based on Phase Congruency
- Author
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Jun Tong, Ying Sun, Zhitao Xiao, Lei Geng, Wu Jun, Fang Zhang, and Lei Pei
- Subjects
Materials science ,Braided composite ,Chemical technology ,pitch length ,02 engineering and technology ,parameter measurement ,TP1-1185 ,021001 nanoscience & nanotechnology ,phase congruency ,Phase congruency ,020303 mechanical engineering & transports ,0203 mechanical engineering ,General Materials Science ,Composite material ,surface braiding angle ,0210 nano-technology ,Pitch length ,2d biaxial braided composite preform - Abstract
In this paper, a new method based on phase congruency is proposed to measure pitch lengths and surface braiding angles of two-dimensional biaxial braided composite preforms. Lab space transform and BM3D (block-matching and 3D filter) are used first to preprocess the original acquired images. A corner detection algorithm based on phase congruency is then proposed to detect the corners of the preprocessed images. Pitch lengths and surface braiding angles are finally measured based on the detected corner maps. Experimental results show that our method achieves the automatic measurement of pitch lengths and the surface braiding angles of biaxial braided composite preforms with high accuracy.
- Published
- 2019
242. Constraints of late Cambrian mafic rocks from the Qushi'ang ophiolite on a back-arc system in a continental margin, East Kunlun Orogen, Western China
- Author
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Keng Feng, Meng Wang, Bo Wei, Xianzhi Pei, Guochao Cheng, Lei Pei, Youxin Chen, Zuochen Li, Chengjun Liu, and Ruibao Li
- Subjects
Basalt ,010504 meteorology & atmospheric sciences ,Mantle wedge ,Geochemistry ,Geology ,010502 geochemistry & geophysics ,Ophiolite ,01 natural sciences ,Continental margin ,Back-arc basin ,Arc system ,Mafic ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Zircon - Abstract
Early Palaeozoic ophiolites emplaced in the central East Kunlun fault zone (CEKF) offer critical clues to the tectonic evolution of the Proto-Tethys ocean and the accretionary process of CEKF. The Qushi'ang Ophiolite, located within the eastern segment of the CEKF, consists of dismembered serpentinites, meta-gabbros and meta-basalts. This study presents petrologic, whole-rock geochemical, and in situ zircon U-Pb and Hf isotope data for basic rocks (both metagabbros and metabasalts) from the Qushi'ang ophiolite to constrain the formation age and tectonic setting of the ophiolite. Zircons from two meta-gabbro samples yield concordant U-Pb ages of ca. 498 Ma and ca. 505 Ma, indicating that the Qushi'ang ophiolite was formed in the late Cambrian. The meta-gabbros and meta-basalts show significant enrichment in large ionic lithophile elements (LILEs), such as Cs, Rb, Ba, U, and Pb, and depletion in high field strength elements (HFSEs), such as Nb, Ta, Zr, and Ti, suggesting the influence of fluids derived from a subducting oceanic slab. On the N-MORB normalized trace element diagrams, these rocks share similar features with arc basalts and back-arc basalts and far away from fore-arc basalts (FABs) and normal mid-ocean basalts (N-MORBs). Low zircon eHf(t) values (−2.9 to +0.2) for the meta-gabbros further indicate that the Qushi'ang ophiolite likely originated from an weakly enriched mantle wedge source. Geochemical discrimination diagrams show that the Qushi'ang ophiolite formed in a back arc basin setting. Our new analyses, combined with previous data, suggest that the Qushi'ang ophiolite represents a relict of a nascent back-arc basin, similar to the scenario of the Okinawa trough in Western Pacific.
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- 2019
243. Transport properties and photoresponse of a series of 2D transition metal dichalcogenide intercalation compounds
- Author
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Guiling Zhang, Zhao-Di Yang, Lei Pei, Yangyang Hu, Yingjie Jiang, Hong Yu, Cuicui Sun, Yuxiu Wang, Shengnan Gao, and Ping Pan
- Subjects
Photocurrent ,Band gap ,Chemistry ,Intercalation (chemistry) ,Quantum yield ,02 engineering and technology ,General Chemistry ,Photon energy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular physics ,Catalysis ,0104 chemical sciences ,Zigzag ,Materials Chemistry ,Density functional theory ,0210 nano-technology ,HOMO/LUMO - Abstract
A series of 2D transition metal dichalcogenide (TMD) intercalation compounds, PdCl2/PtCl2@MX2 (M = Mo, W; X = S, Se), formed by covalently intercalating PdCl2/PtCl2 into the bilayer space of MX2, have been designed and investigated using density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods. The intercalation compounds adopt a planar quadridentate coordination structure of PdCl2X2/PtCl2X2. The possibility of electron–hole recombination is enhanced because of the introduction of the PdCl2/PtCl2 groups, and on the other hand, the PdCl2/PtCl2-derived HOMO and LUMO are shielded well by the MX2 band gap, both of which are beneficial for improving the fluorescence quantum yield. The conductivity of the intercalation compounds is slightly lowered owing to the trap effect of PdCl2/PtCl2. In addition, electron transportation is easier along the zigzag direction than along the armchair direction. Contrary to the conductivity, a robust photogalvanic effect (PGE) can be observed when linearly polarized light is applied onto the PdCl2/PtCl2 groups, and the armchair direction exhibits a much higher photoresponse compared with the zigzag direction. The largest photocurrent could reach up to 1.83 × 10−2 a02 per photon. For a given MX2, the PdCl2 groups induce a higher maximum photocurrent than the PtCl2. Significantly, the photocurrent is highly dependent on the polarization angle θ and the applied photon energy, making the intercalation compounds appealing for designing photoresponse on/off switches by tuning θ or photon energy. Our simulation frameworks as well as the results offer guidelines for novel 2D functional device design and fabrication.
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- 2019
244. Facile synthesis of polyacrylonitrile-based N/S-codoped porous carbon as an efficient oxygen reduction electrocatalyst for zinc–air batteries
- Author
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Lei Pei, Qi Hu, Bin Zhu, Guodong Li, Jianhong Liu, Qianling Zhang, Hengpan Yang, Yu Wu, and Chuanxin He
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Materials science ,Renewable Energy, Sustainability and the Environment ,Polyacrylonitrile ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Zinc ,021001 nanoscience & nanotechnology ,Electrocatalyst ,Catalysis ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Specific surface area ,General Materials Science ,Thermal stability ,Methanol ,0210 nano-technology ,Power density - Abstract
Polyacrylonitrile (PAN) is an attractive precursor for N-doped porous carbons owing to its high nitrogen content and good thermal stability. Herein, a facile and effective route for the synthesis of N/S co-doped porous carbon by capitalizing on hetero-atom containing PAN as a doped carbon source and ZnCl2 as a volatile porogen is reported. Notably, the optimal porous carbon (denoted as FeZ-CNS-900) with a large specific surface area of up to 1730 m2 g−1 exhibits excellent oxygen reduction reaction (ORR) activity with a half-wave potential of 0.881 V, which is 39 mV more positive than that of commercial Pt/C under alkaline conditions, as well as robust durability and methanol tolerance. Interestingly, the use of N/S co-doped porous carbon also offers comparable ORR activity yet much higher stability than that of Pt/C under acidic conditions. Finally, the implementation of FeZ-CNS-900 as the air-cathode catalyst for primary Zn–air batteries yields an open-circuit potential of 1.49 V, a high peak power density of 168 mW cm−2, a large specific capacity of 778 mA h gZn−1 (corresponding to an energy density of 1020 W h kgZn−1) and a remarkable durability.
- Published
- 2019
245. Optimization of optical properties and durability performances of amorphous IZO transparent conductive films by preparing silicone coatings
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Hao Changshan, Zhang Xiaofeng, Zhong Yanli, Lei Pei, Huo Zhongqi, Ji Jianchao, and Zhang Xuan
- Subjects
General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Surfaces, Coatings and Films - Published
- 2022
246. Comparative analysis of P2X1, P2X2, P2X3, and P2X4 receptor subunits in rat nodose ganglion neurons.
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Lizhao Wang, Dan Feng, Huanhuan Yan, Zhongping Wang, and Lei Pei
- Subjects
Medicine ,Science - Abstract
Nodose ganglion (NG) neurons are visceral primary sensory neurons. The transmission and regulation of visceral sensation is mediated mainly by the P2X purinoceptor (P2X receptor). Although the characteristics of different P2X receptor subunits in the NG have been studied previously, comprehensive analyses have not been performed. In this study, we used immunohistochemistry, immunocytochemistry, and whole cell patch clamp techniques to compare the expression and function of P2X1, P2X2, P2X3, and P2X4 receptor subunits in adult rat NG neurons. Polyclonal antibodies against the four P2X subunits labeled different subpopulations of NG neurons. P2X1 and P2X3 were expressed mainly in small-to-medium sized NG neurons, whereas P2X2 and P2X4 were located mostly in medium- and larger-sized NG neurons. Over 36% of NG neurons were P2X3 positive, which was higher than the other three P2X subunits. In addition, different types of currents were recorded from neurons expressing different P2X subunits. The fast type of ATP current was recorded from neurons containing P2X1-4 subunits, the intermediate type of current was recorded from neurons containing the P2X1, P2X3, and P2X4 subunits, the slow type was recorded from neurons expressing P2X1-3, and/or P2X4 subunits, whereas the very slow type was recorded from neurons containing the P2X2 and P2X3 subunits. These comparative results provide an anatomical verification of the different subunits in NG neurons, and offer direct support for the idea that various functional NG populations have distinct responses to ATP, which might be in part due to the different expression profiles of diverse P2X subunits.
- Published
- 2014
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- View/download PDF
247. Association of Circulating Adipsin, Visfatin, and Adiponectin with Nonalcoholic Fatty Liver Disease in Adults: A Case-Control Study
- Author
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Nengzhi Pang, Yuanling Huang, Rui Jiang, Zhenfeng Zhang, Lei Pei, Yun Qiu, Lili Yang, Chao Yu, Wenhua Ling, Qian Chen, and Sufan Wang
- Subjects
Adult ,Male ,0301 basic medicine ,China ,medicine.medical_specialty ,Medicine (miscellaneous) ,Adipokine ,030209 endocrinology & metabolism ,Pathogenesis ,03 medical and health sciences ,0302 clinical medicine ,Adipokines ,Asian People ,Non-alcoholic Fatty Liver Disease ,Internal medicine ,Nonalcoholic fatty liver disease ,medicine ,Humans ,Nicotinamide Phosphoribosyltransferase ,030109 nutrition & dietetics ,Nutrition and Dietetics ,Adiponectin ,business.industry ,Leptin ,Confounding ,Case-control study ,nutritional and metabolic diseases ,medicine.disease ,Obesity ,digestive system diseases ,Endocrinology ,Case-Control Studies ,Cytokines ,Complement Factor D ,Female ,business - Abstract
Background/Aims: Some adipokines, such as adiponectin and leptin, have been reported to be involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD), while the association of adipsin and visfatin with NAFLD still remains unclear. This study aimed to examine the association of circulating adipsin, visfatin, and adiponectin with NAFLD in Chinese adults. Methods: We recruited a total of 211 eligible subjects, including 100 NAFLD cases and 111 age and sex frequency-matched controls. Circulating adipsin, visfatin, and adiponection concentrations were measured by enzymatic immunoassay. Unconditional logistic regression was conducted to assess the associations between quartiles of adipokines and NAFLD. Results: Compared with the controls, NAFLD cases had higher levels of adipsin and lower levels of visfatin and adiponectin. By multivariate logistic analysis, adjusting for potential confounders, circulating adipsin levels were found to be positively associated with NAFLD risk, and circulating levels of visfatin and adiponectin were inversely associated with the risk of NAFLD (all p-trend < 0.05). The ORs were 3.76 (95% CI 1.27–11.08) for adipsin, 0.30 (95% CI 0.10–0.91) for visfatin, and 0.30 (95% CI 0.10–0.88) for adiponectin comparing subjects in the highest quartile with those in the lowest. After stratified by obesity status, the association of higher adipsin with increased risk of NAFLD was only observed in nonobese group. Additionally, the inverse association between adiponectin and NAFLD was found in both groups. Conclusions: These results indicated that increased circulating levels of adipsin and decreased circulating levels of visfatin and adiponectin were independently associated with the increased risk of NAFLD.
- Published
- 2018
248. Death-associated Protein Kinase 1 Impairs the Hippocampo-prefrontal Cortical Circuit and Mediates Post-stroke Depression
- Author
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Yao Yi, Dian Yu, Se-Hui Ma, Hongyan Yu, Xiao Ke, Lei Pei, and Yufen Zhang
- Subjects
business.industry ,musculoskeletal, neural, and ocular physiology ,Glutamate receptor ,Hippocampal formation ,medicine.disease ,Glutamatergic ,nervous system ,mental disorders ,Synaptic plasticity ,Biological neural network ,medicine ,Post-stroke depression ,Prefrontal cortex ,business ,Neuroscience ,Stroke ,psychological phenomena and processes - Abstract
Post-stroke depression (PSD) is a common and complex post-stroke neuropsychiatric disorder, which not only delays functional recovery but also increases mortality, and which currently lacks effective drug therapy. The pathogenesis of PSD is associated with impairment of the subcortical neural circuits and alterations of synaptic plasticity and neurotransmitters, but the exact mechanisms of PSD remain unknown. Our previous work indicates that the death-associated protein kinase 1 (DAPK1) mediates neuronal death after stroke. Genetic deletion of DAPK1 gene or blocking DAPK1 signal in the PSD mouse model can not only alleviate cerebral ischemic injury but also relieve PSD-like behaviors. Our previous work has also demonstrated the following results. First, the neural circuit of dorsal CA1 (dCA1) to medial prefrontal cortex (mPFC) (dCA1-mPFC) is selectively impaired after stroke. Second, the DAPK1 signal is involved in the impairment of dCA1-mPFC neural circuit after stroke. Third, genetic deletion of the DAPK1 gene or blocking of the DAPK1 signal alleviates the injury of dCA1-mPFC neural circuit after stroke and improves PSD-like behaviors. In conclusion, we hypothesize that activated DAPK1 signal after stroke induces apoptosis in the hippocampal dCA1 neurons, leading to loss of the dCA1-mPFC glutamatergic projections, synaptic injury, decrease of glutamate release, inhibition of mPFC neurons, and finally onset of PSD. We hope to further replenish the mechanisms of PSD and provide new insights for PSD treatment.
- Published
- 2018
249. Normal stress in magnetorheological polymer gel under large amplitude oscillatory shear
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Haoming Pang, Chuanlin Sun, Xinglong Gong, and Lei Pei
- Subjects
Shearing (physics) ,Normal force ,Materials science ,010304 chemical physics ,Mechanical Engineering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Oscillatory shear ,Amplitude ,Shear (geology) ,Mechanics of Materials ,0103 physical sciences ,Poynting vector ,Magnetorheological fluid ,Perpendicular ,General Materials Science ,Composite material ,0210 nano-technology - Abstract
In this study, the normal stress in magnetorheological polymer gel (MRPG) under large amplitude oscillatory shear was investigated using experiments and particle-level simulations. Under large amplitude oscillatory shear, an intensely oscillating normal stress was measured with a period of exactly half the strain period. As the amplitude of the strain increased, the peak of the normal stress increased and the trough decreased. Changes in the normal stress were mainly caused by two factors: the Poynting effect, in which shear produces a normal force perpendicular to the shear direction, and magnetic-induced normal stress, which changes with the particle structure. In MRPG, both effects are related to the particle structure. The particle structure in MRPG with different strain was calculated and the simulation results show that the amplitude of the structural strain in oscillatory shearing is less than that of the applied strain. Additionally, a phase difference was observed between the structural strain and the applied strain. Based on the calculated particle structure, the change in the normal stress was obtained and found to agree well with the experimental results.
- Published
- 2018
250. Chemotherapy-driven increases in the CDKN1A/PTN/PTPRZ1 axis promote chemoresistance by activating the NF-κB pathway in breast cancer cells
- Author
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Lun Li, Qianying Li, Wenjun Yi, Rong Zeng, Qiongyan Zou, Dengjie Ouyang, Moyun Li, Piao Zhao, Shi Chang, Peng Huang, Lei Pei, and Juan Su
- Subjects
Cyclin-Dependent Kinase Inhibitor p21 ,0301 basic medicine ,lcsh:Medicine ,Apoptosis ,Triple Negative Breast Neoplasms ,Pleiotrophin ,Biochemistry ,NF-κB signalling pathway ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Breast cancer ,Downregulation and upregulation ,Cell Line, Tumor ,medicine ,Humans ,lcsh:QH573-671 ,Molecular Biology ,Cell Proliferation ,Protein tyrosine phosphatase receptor Z1 ,Feedback, Physiological ,Receptor-Like Protein Tyrosine Phosphatases, Class 5 ,business.industry ,Microarray analysis techniques ,lcsh:Cytology ,Research ,lcsh:R ,NF-kappa B ,Cancer ,NF-κB ,Cell Biology ,medicine.disease ,Gene Expression Regulation, Neoplastic ,030104 developmental biology ,chemistry ,Drug Resistance, Neoplasm ,030220 oncology & carcinogenesis ,PTPRZ1 ,Cancer research ,Cytokines ,Carrier Proteins ,business ,Chemotherapy resistance ,Signal Transduction - Abstract
Background Chemotherapy is the primary established systemic treatment for patients with breast cancer, especially those with the triple-negative subtype. Simultaneously, the resistance of triple-negative breast cancer (TNBC) to chemotherapy remains a major clinical problem. Our previous study demonstrated that the expression levels of PTN and its receptor PTPRZ1 were upregulated in recurrent TNBC tissue after chemotherapy, and this increase was closely related to poor prognosis in those patients. However, the mechanism and function of chemotherapy-driven increases in PTN/PTPRZ1 expression are still unclear. Methods We compared the expression of PTN and PTPRZ1 between normal breast and cancer tissues as well as before and after chemotherapy in cancer tissue using the microarray analysis data from the GEPIA database and GEO database. The role of chemotherapy-driven increases in PTN/PTPRZ1 expression was examined with a CCK-8 assay, colony formation efficiency assay and apoptosis analysis with TNBC cells. The potential upstream pathways involved in the chemotherapy-driven increases in PTN/PTPRZ1 expression in TNBC cells were explored using microarray analysis, and the downstream mechanism was dissected with siRNA. Results We demonstrated that the expression of PTN and PTPRZ1 was upregulated by chemotherapy, and this change in expression decreased chemosensitivity by promoting tumour proliferation and inhibiting apoptosis. CDKN1A was the critical switch that regulated the expression of PTN/PTPRZ1 in TNBC cells receiving chemotherapy. We further demonstrated that the mechanism of chemoresistance by chemotherapy-driven increases in the CDKN1A/PTN/PTPRZ1 axis depended on the NF-κB pathway. Conclusions Our studies indicated that chemotherapy-driven increases in the CDKN1A/PTN/PTPRZ1 axis play a critical role in chemoresistance, which suggests a novel strategy to enhance chemosensitivity in breast cancer cells, especially in those of the triple-negative subtype.
- Published
- 2018
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