Filters








25 Hits in 1.3 sec

Rapid Determination of Chlorogenic Acid, Luteoloside and 3,5-O-dicaffeoylquinic Acid in Chrysanthemum Using Near-Infrared Spectroscopy

Zhengyan Xia, Yiming Sun, Chengyong Cai, Yong He, Pengcheng Nie
2019 Sensors  
The feasibility of near-infrared spectroscopy (NIR) to detect chlorogenic acid, luteoloside and 3,5-O-dicaffeoylquinic acid in Chrysanthemum was investigated. An NIR spectroradiometer was applied for data acquisition. The reference values of chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid of the samples were determined by high-performance liquid chromatography (HPLC) and were used for model calibration. The results of six preprocessing methods were compared. To reduce input
more » ... les and collinearity problems, three methods for variable selection were compared, including successive projections algorithm (SPA), genetic algorithm-partial least squares regression (GA-PLS), and competitive adaptive reweighted sampling (CARS). The selected variables were employed as the inputs of partial least square (PLS), back propagation-artificial neural networks (BP-ANN), and extreme learning machine (ELM) models. The best performance was achieved by BP-ANN models based on variables selected by CARS for all three chemical constituents. The values of rp2 (correlation coefficient of prediction) were 0.924, 0.927, 0.933, the values of RMSEP were 0.033, 0.018, 0.064 and the values of RPD were 3.667, 3.667, 2.891 for chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid, respectively. The results indicated that NIR spectroscopy combined with variables selection and multivariate calibration methods could be considered as a useful tool for rapid determination of chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid in Chrysanthemum.
doi:10.3390/s19091981 fatcat:wjrtbcgoxfajnjlxpq3iauxqha

Assembly of indole-2-carboxylic acid esters through a ligand-free copper-catalysed cascade process

Qian Cai, Zhengqiu Li, Jiajia Wei, Chengyong Ha, Duanqing Pei, Ke Ding
2009 Chemical Communications  
Typical procedure for the preparation of Indole-2-Carboxylic Acid Esters: The aryl halides, base, copper salts and solvent were added together into a reacting tube under nitrogen atmosphere. Then ethyl isocyanoacetate was slowly added and the mixtures were stirred at certain temperature. After the reactions were finished, ethyl acetate and water were added. The organic phase was separated, dried over sodium sulphate and evaporated in vacuum. The residues were loaded on silica gel column and
more » ... fied to get the final products. Ethyl 1H-indole-2-carboxylate (5) [1] N H CO 2 Et 1 H NMR (CDCl 3 , 400 MHz) δ 8.99 (br, 1H), 7.68 (m, 1H), 7.13-7.42 (m, 4H), 4.42 (q, J = 7.2 Hz, 2H), 1.43 (t, J = 7.2 Hz, 3H); ESI-MS m/z 189.9 (M+H) + . Ethyl 5-methyl-1H-indole-2-carboxylate (7a) [2] N H CO 2 Et Me 1 H NMR (CDCl 3 , 400 MHz) δ 8.88 (br, 1H), 7.56 (d, J = 8.0 Hz, 1H), 7.19 (m, 2H), 7.00 (d, J = 8.0 Hz 1H), 4.41 (q, J = 7.2 Hz, 2H), 2.47 (s, 3H), 1.41 (t, J = 7.2 Hz, 3H). ESI-MS m/z 204.1 (M+H) + . Ethyl 5-chloro-1H-indole-2-carboxylate (7b) [3] N H CO 2 Et Cl 1 H NMR (CDCl 3 , 400 MHz) δ 9.25 (br, 1H), 7.65 (s, 1H), 7.35 (d, J = 8.8 Hz, 1H), 7.26 (d, J = 8.8 Hz, 1H), 7.15 (s, 1H), 4.43 (q, J = 7.2 Hz, 2H), 1.45 (t, J = 7.2 Hz, 3H), ESI-MS m/z 222.0 (M-H) -. Ethyl 5, 6-dimethoxy-1H-indole-2-carboxylate (7c) [4] N H CO 2 Et MeO MeO 1 H NMR (CDCl 3 , 400 MHz) δ 9.06 (br, 1H), 7.11 (s, 1H), 7.03 (s, 1H), 6.84 (s, 1H), 4.39 (q, J = 7.2 Hz, 2H), 3.91 (s, 3H), 1.39 (t, J = 7.2 Hz, 3H), ESI-MS m/z 250.0 (M+H) + . Ethyl 5-(trifluoromethyl)-1H-indole-2-carboxylate (7d) [5] N H CO 2 Et F 3 C 1 H NMR (CDCl 3 , 400 MHz) δ 9.55 (br, 1H), 8.00(s, 1H), 7.55-7.50 (m, 2H), 7.30 (s, 1H), 4.46 (q, J = 7.2 Hz, 2H), 1.43 (t, J = 7.2 Hz, 3H), ESI-MS m/z 256.0 (M-H) -. Ethyl 1H-benzo[g]indole-2-carboxylate (7e) [6] N H CO 2 Et 1 H NMR (CDCl 3 , 400 MHz) δ 9.95 (br, 1H), 8.19 (d, J = 8.0 Hz, 1H), 7.92 (d, J = 7.6 Hz, 1H), 7.68 (d, J = 8.8 Hz, 1H), 7.59-7.49 (m, 3H), 7.35 (s, 1H), 4.47 (q, J = 7.2 Hz, 2H), 1.46 (t, J = 7.2 Hz, 3H), ESI-MS m/z 240.0 (M+H) + . Ethyl 1H-pyrrolo [2, 3-b] pyridine-2-carboxylate (7f) [7] N N H CO 2 Et 1 H NMR (CDCl 3 , 400 MHz) δ 11.58 (br, 1H), 8.61 (m, 1H), 8.05 (m, 1H), 7.19-7.15 (m, 2H), 4.46 (q, J = 6.8 Hz, 2H), 1.39 (t, J = 6.8 Hz, 3H). ESI-MS m/z 191.1 (M+H) + . Ethyl 6-methyl-4H-thieno [3, 2-b] pyrrole-5-carboxylate (7g) [8] S H N CO 2 Et ESI-MS m/z 209.9 (M+H) + . Ethyl 3-methyl-1H-indole-2-carboxylate (7h) [9] N H CO 2 Et 1 H NMR (CDCl 3 , 400 MHz) δ 8.79 (br, 1H), 7.67 (d, J = 8.4 Hz, 1H), 7.38-7.30 (m, 2H), 7.16-7.13 (m, 1H), 4.42 (q, J = 7.2 Hz, 2H), 2.62 (s, 3H), 1.43 (t, J = 7.2 Hz, 3H). ESI-MS m/z 204.1 (M+H) + . Ethyl 3-(4-acetamidophenethyl)-1H-indole-2-carboxylate (7i) Supplementary Material (ESI)
doi:10.1039/b918345k pmid:20024286 fatcat:bquhhusdl5gtffgshjnzislqlm

Molecular Characterization and Theoretical Calculation of Plant Growth Regulators Based on Terahertz Time-Domain Spectroscopy

Fangfang Qu, Lei Lin, Chengyong Cai, Tao Dong, Yong He, Pengcheng Nie
2018 Applied Sciences  
Fangfang Qu, Lei Lin, Tao Dong and Chengyong Cai co-worked on associated data collection and carried out the experimental work.  ... 
doi:10.3390/app8030420 fatcat:5rdfgiw35zcevht4sysuzszdoy

Study of 2,4-D Spectral Characteristics and Its Detection in Zizania Latifolia Using Terahertz Time-Domain Spectroscopy

Pengcheng Nie, Chengyong Cai, Fangfang Qu, Lei Lin, Tao Dong, Yong He
2019 Applied Sciences  
2,4-Dichlorophenoxyacetic acid (2,4-D) is a common plant growth regulator, which can remain in food and, with long-term consumption, threaten human health. Therefore, it is necessary to propose an effective detection method. Terahertz time-domain spectroscopy technique (THz-TDS) has good advantages in the quantitative and qualitative analysis of most biomolecules due to its rich fingerprint characteristics. In this paper, density functional theory (DFT) was applied to geometry optimization and
more » ... requency vibration calculation of 2,4-D, and THz-TDS was used to quantitatively detect 2,4-D in Zizania latifolia. The results showed that there were three characteristic absorption peaks of 2,4-D at 1.36, 1.60, and 2.38 THz, respectively, and the theoretical spectra were in good consistency with experimental spectra, with slight discrepancies. Additionally, the absorption peak at 1.36 THz had the best absorption characteristics and was chosen as the main peak for 2,4-D quantitative analysis. It was demonstrated that the limits of detection (LOD) of 2,4-D in Zizania latifolia were found to be as low as 5%, the absorbance intensity at 1.36 THz showed a good linear relationship (R2 = 0.9854) with 2,4-D concentration from 5% to 30%, and the recovery was 93.29%–98.75%. Overall, this work enriched the fingerprint database of pesticide molecules on the basis of terahertz spectroscopy and could provide a technical support for the detection of 2,4-D in food by terahertz spectroscopy.
doi:10.3390/app9112248 fatcat:atb6p4j2anaozlzg35uirhhdgm

The role of S100B/RAGE-enhanced ADAM17 activation in endothelial glycocalyx shedding after traumatic brain injury

Zhimin Zou, Li Li, Qin Li, Peng Zhao, Kun Zhang, Chengyong Liu, Daozhang Cai, Marc Maegele, Zhengtao Gu, Qiaobing Huang
2022 Journal of Neuroinflammation  
Background Traumatic brain injury (TBI) remains one of the main causes for disability and death worldwide. While the primary mechanical injury cannot be avoided, the prevention of secondary injury is the focus of TBI research. Present study aimed to elucidate the effects and mechanisms of S100B and its receptor RAGE on mediating secondary injury after TBI. Methods This study established TBI animal model by fluid percussion injury in rats, cell model by stretch-injured in astrocytes, and
more » ... ial injury model with conditioned medium stimulation. Pharmacological intervention was applied to interfere the activities of S100B/RAGE/ADAM17 signaling pathway, respectively. The expressions or contents of S100B, RAGE, syndecan-1 and ADAM17 in brain and serum, as well as in cultured cells and medium, were detected by western blot. The distribution of relative molecules was observed with immunofluorescence. Results We found that TBI could activate the release of S100B, mostly from astrocytes, and S100B and RAGE could mutually regulate their expression and activation. Most importantly, present study revealed an obvious increase of syndecan-1 in rat serum or in endothelial cultured medium after injury, and a significant decrease in tissue and in cultured endothelial cells, indicating TBI-induced shedding of endothelial glycocalyx. The data further proved that the activation of S100B/RAGE signaling could promote the shedding of endothelial glycocalyx by enhancing the expression, translocation and activity of ADAM17, an important sheddase, in endothelial cells. The damage of endothelial glycocalyx consequently aggravated blood brain barrier (BBB) dysfunction and systemic vascular hyper-permeability, overall resulting in secondary brain and lung injury. Conclusions TBI triggers the activation of S100B/RAGE signal pathway. The regulation S100B/RAGE on ADAM17 expression, translocation and activation further promotes the shedding of endothelial glycocalyx, aggravates the dysfunction of BBB, and increases the vascular permeability, leading to secondary brain and lung injury. Present study may open a new corridor for the more in-depth understanding of the molecular processes responsible for cerebral and systemic vascular barrier impairment and secondary injury after TBI.
doi:10.1186/s12974-022-02412-2 pmid:35148784 pmcid:PMC8832692 fatcat:wluqfekhazcp3bxgepudmpzn6u

Review of theoretical methods and research aspects for detecting leaf water content using terahertz spectroscopy and imaging

Fangfang Qu, Pengcheng Nie, Lei Lin, Chengyong Cai, Yong He
2018 International Journal of Agricultural and Biological Engineering  
The water content in vegetative leaves is an important indicator to plant science. It reveals the physiological status of plants and provides valuable information in irrigation management. Terahertz (THz) as a state-of-the-art technology shows great potential in measuring and monitoring the water status in plant leaves. This paper reviewed the theoretical models for calculating water content in the plant leaves, the methods for eliminating the scattering loss caused by the surface roughness of
more » ... eaf, the applications of THz spectroscopy and THz imaging for monitoring leaf water content and describing leaf water distribution. The survey of the researches presents the considerable advantages of this emerging and promising THz technology in agriculture.
doi:10.25165/j.ijabe.20181105.3952 fatcat:hjck2vurjza2tf7y7ngewpfi7q

Spectral Characterization and Molecular Dynamics Simulation of Pesticides Based on Terahertz Time-Domain Spectra Analyses and Density Functional Theory (DFT) Calculations

Fangfang Qu, Lei Lin, Yong He, Pengcheng Nie, Chengyong Cai, Tao Dong, Yi Pan, Yu Tang, Shaoming Luo
2018 Molecules  
This work provides the experimental and theoretical fundamentals for detecting the molecular fingerprints of six kinds of pesticides by using terahertz (THz) time-domain spectroscopy (THz-TDS). The spectra of absorption coefficient and refractive index of the pesticides, chlorpyrifos, fipronil, carbofuran, dimethoate, methomyl, and thidiazuron are obtained in frequencies of 0.1-3.5 THz. To accurately describe the THz spectral characteristics of pesticides, the wavelet threshold de-noising (WTD)
more » ... method with db 5 wavelet fucntion, 5-layer decomposition, and soft-threshold de-noising was used to eliminate the spectral noise. The spectral baseline correction (SBC) method based on asymmetric least squares smoothing was used to remove the baseline drift. Spectral results show that chlorpyrifo had three characteristic absorption peaks at 1.47, 1.93, and 2.73 THz. Fipronil showed three peaks at 0.76, 1.23, and 2.31 THz. Carbofuran showed two peaks at 2.72 and 3.06 THz. Dimethoate showed three peaks at 1.05, 1.89, and 2.92 THz. Methomyl showed five peaks at 1. 01, 1.65, 1.91, 2.72, and 3.20 THz. Thidiazuron showed four peaks at 0.99, 1.57, 2.17, and 2.66 THz. The density functional theory (DFT) of B3LYP/6-31G+(d,p) was applied to simulate the molecular dynamics for peak analyzing of the pesticides based on isolated molecules. The theoretical spectra are in good agreement with the experimental spectra processed by WTD + SBC, which implies the validity of WTD + SBC spectral processing methods and the accuracy of DFT spectral peak analysis. These results support that the combination of THz-TDS and DFT is an effective tool for pesticide fingerprint analysis and the molecular dynamics simulations.
doi:10.3390/molecules23071607 pmid:30004436 fatcat:vks2kvtpsvb7noodtny5inn4km

Discovery of CNS Penetrant CXCR2 Antagonists for the Potential Treatment of CNS Demyelinating Disorders

Heng Xu, Hongfu Lu, Zhongmiao Xu, Linbo Luan, Chengyong Li, Yan Xu, Kelly Dong, Jinqiang Zhang, Xiong Li, Yvonne Li, Gentao Liu, Sophie Gong (+8 others)
2016 ACS Medicinal Chemistry Letters  
Structure-activity relationship exploration of the historical biarylurea series led to the identification of novel CNS penetrant CXCR2 antagonists with nanomolar potency, favorable PK profile, and good developability potentials. More importantly, the key compound 22 showed efficacy in a cuprizone-induced demyelination model with twice daily oral administration, thereby supporting CXCR2 to be a potential therapeutic target for the treatment of demyelinating diseases such as multiple sclerosis.
doi:10.1021/acsmedchemlett.5b00489 pmid:27096048 pmcid:PMC4834652 fatcat:nznc4aqbjfhhzkp6h6noopllha

Table of Contents

2020 2020 International Conference on Computer Information and Big Data Applications (CIBDA)  
Based on EAST Optimization Algorithm 491 Hanwen Huang (Xi'an Jiaotong University), Yang Yu (Beihang University), Yuluo Lin (Chengdu University of Technology), Yan Zhang (Zhengzhou University), Yijia Cai  ...  Mongolia Agricultural University) and Heru Xue (Inner Mongolia Agricultural University) v Intelligent Management System of Computer Room Based on Internet of Things Technology in Big Data Center 79 Chengyong  ... 
doi:10.1109/cibda50819.2020.00004 fatcat:fm6rjzgofrgarkdkks6ndtinye

Low-Carbon Strategy with Chinese SMEs

Wen Huaide, Tan Jingrong
2011 Energy Procedia  
According to another study, a large part of sulfur dio xide, n itrogen oxides come fro m burning coal in China Cai Bofeng, 2010 .  ...  other developed countries have implemented policies about low-carbon economy, and developed their own detailed distinctive strategies for target of low-carbon economy Le Zhiyong, 2003 Yao Langjun, Sun Chengyong  ... 
doi:10.1016/j.egypro.2011.03.107 fatcat:osk4ejbgjfbq3isnrgivp3thzy

Table of Contents

2021 2021 IEEE 1st International Power Electronics and Application Symposium (PEAS)  
............ 778 Shujian Cong, Qiang Gao, Pengpeng Feng A Hybrid H-bridge Fault Current Limiter for HVDC Grid Protection ................................ 782 Jianzhong Xu, Dongyi Wu, Jun Yan, Gen Li, Chengyong  ...  , Mei Su High-ripple Compact Design of MMC for Medium Voltage Distribution .......................... 821 Kangsheng Cui, Liang Ai, Jian Shi, Biao Zhao, Hong Qi, Haibo Li, Xiaoting Ma, Yuchi Ren, Fang Cai  ... 
doi:10.1109/peas53589.2021.9628817 fatcat:xtr7xgz73fcahif3bg5nfxfg3i

Page 789 of Mathematical Reviews Vol. , Issue Index [page]

Mathematical Reviews  
(English and Romanian summaries) 98a:41034 Xuan, Pei Cai Weighted approximation by multivariabie linear positive operators.  ...  English and Russian summaries) 98h:46021 Sun, Yong Sheng (with Wang, Chengyong) Average error bounds of best approximation in a Banach space with Gaussian measure.  ... 

Clinical Outcomes and Plasma Concentrations of Baloxavir Marboxil and Favipiravir in COVID-19 Patients: an Exploratory Randomized, Controlled Trial [article]

Yan Lou, Lin Liu, Yunqing Qiu
2020 medRxiv   pre-print
Chengyong Yang and 1 2Dr. Guofeng Cheng for their technical support to this study. Dr. Yang and Dr.  ...  Chan JF, Yuan S, Kok KH, To KK, Chu H, Yang J, Xing F, Liu J, Yip CC, Poon RW, Tsoi HW, Lo SK, Chan KH, Poon VK, Chan WM, Ip JD, Cai JP, Cheng VC, Chen H, Hui CK, Yuen KY.  ... 
doi:10.1101/2020.04.29.20085761 fatcat:sxmqtc6xhjcylm7n6iu3ihhztq

Antibody responses to SARS-CoV-2 in COVID-19 patients: the perspective application of serological tests in clinical practice [article]

Quan-xin Long, Hai-jun Deng, Juan Chen, Jieli Hu, Bei-zhong Liu, Pu Liao, Yong Lin, Li-hua Yu, Zhan Mo, Yin-yin Xu, Fang Gong, Gui-cheng Wu (+35 others)
2020 medRxiv   pre-print
We thank Chengyong Yang, Law Yuen Kwan and Ju Cao for critical reviewing of the manuscript.Financial support.  ... 
doi:10.1101/2020.03.18.20038018 fatcat:6usx2vq5tvf2pl662wpz5xirsa

miR-34a overexpression protects against hippocampal neuron damage caused by ketamine-induced anesthesia in immature rats through the Notch-1/NF-κB signaling pathway

Xueyan Li, Genshan Ma, Chun Zhang, Mo Chen, Xiaochen Huang, Chengyong Gu
2021
IFITM3, TLR3, and [20] Huang X, Dai Z, Cai L, Sun K, Cho J, Albertine CD55 gene SNPs and cumulative genetic risks KH, Malik AB, Schraufnagel DE and Zhao YY.  ...  against hippocampal neuron damage caused by ketamine-induced anesthesia in immature rats through the Notch-1/NF-κB signaling pathway Xueyan Li1*, Genshan Ma2*, Chun Zhang1, Mo Chen1, Xiaochen Huang1, Chengyong  ... 
pmid:35035687 pmcid:PMC8748079 fatcat:vxkjcmajhnhfzjrgblrq53c25i
« Previous Showing results 1 — 15 out of 25 results