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Solid electrochemiluminescence sensor by immobilization luminol in Zn-Co-ZIF CNFs for sensitive detection of procymidone in vegetables

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MICROCHIMICA ACTA 2024年第9期191卷 508-508页

作者： Lu, Juan Guo, Yanjia Shan, Xiangyu Song, Yujia li, Ruidan Tian, li li, xuwen Changchun Normal Univ Coll Chem Changchun 130032 Peoples R China Jilin Univ Coll Chem Changchun 130022 Peoples R China Technol Innovat Lab Res & Dev Econ Plants & Edible Changchun 130032 Jilin Peoples R China

A solid-state electrochemiluminescence (ECL) sensor was fabricated by immobilizing luminol, a classical luminescent reagent, on a Zn-Co-ZIF carbon fiber-modified electrode for the rapid and sensitive detection of procymidone (PCM) in vegetable samples. The sensor was created by sequentially modifying the glassy carbon electrode with Zn-Co-ZIF carbon fiber (Zn-Co-ZIF CNFs), Pt@Au NPs, and luminol. Zn-Co-ZIF CNFs, prepared through electrospinning and high-temperature pyrolysis, possessed a large specific surface area and porosity, making it suitable as carrier and electron transfer accelerator in the system. Pt@Au NPs demonstrated excellent catalytic activity, effectively enhancing the generation of active substances. The ECL signal was significantly amplified by the combination of Zn-Co-ZIF CNFs and Pt@Au NPs, which can subsequently be diminished by procymidone. The ECL intensity decreased proportionally with the addition of procymidone, displaying a linear relationship within the concentration range 1.0 x 10-13 to 1.0 x 10-6 mol L-1 (R2 = 0.993). The sensor exhibited a detection limit of 3.3 x 10-14 mol L-1 (S/N = 3) and demonstrated outstanding reproducibility and stability, making it well-suited for the detection of procymidone in vegetable samples.

关键词： Electrochemiluminescence Carbon nanofibers Modified glassy carbon electrode Procymidone Luminol

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Selective Frustrated/Nonfrustrated Anion-Migrated Ring-Opening Polymerization of 1-Cyclopropylvinylbenzene

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MACROMOLECULES 2022年第12期55卷 5140-5148页

作者： Bai, Hongyuan Wang, Yinran Han, li Wang, Xuefei Yan, Hong li, xuwen Chen, Siwei Leng, Haitao Yao, Zijing Ma, Hongwei Dalian Univ Technol Sch Chem Engn Dept Polymer Sci & Engn Dalian 116024 Peoples R China

Exploring novel polymerization mechanisms for the preparation of switchable isomers in chains from homopolymerization with only monomers is undoubtedly an exhilarating and challenging pursuit in polymer chemistry. Therefore, this work presents a novel strategy for realizing reversible cycle anion migrated ring-opening polymerization (AMROP) and general anionic polymerization (thermodynamics limits the further ring-opening reaction of the 1-cyclopropylvinylbenzene (CPVB) unit, and this process is defined as frustrated AMROP). By employing alkali metal alkoxides (potassium tert-butoxide (t-BuOK) and sodium 2,3-dimethylpentan-3-olate (NaODP)) as additives, the opening of the cyclopropyl group in CPVB can be controlled during homopolymerization. Additionally, the structure and sequence distribution of inserted CPVB units are determined by distinct selective polymerization mechanisms. Thus, the synthetic polymer includes two structural units, i.e., ring-opened CPVB (ro), which is generated from AMROP, and nonopened CPVB (ga), which results from frustrated AMROP (F-AMROP). Furthermore, in view of steric hindrance from the penultimate-unit effect during chain growth of CPVB, the process of F-AMROP cannot continuously occur and requires the AMRO process of CPVB to decrease the steric hindrance around active centers. Therefor;under the influence of steric hindrance from the penultimate unit, AMRO, and thermodynamics, a reversible cycle of frustrated and nonfrustrated AMROP can be activated during the polymerization process, which further realizes a single monomer to prepare an alternating polymer with different isomers. Ultimately, the mechanisms for AMROP and F-AMROP are explored deeply with density functional theory calculations. This intriguing mechanistic finding will become a pioneering and innovative strategy for development of polymerization mechanisms and unprecedented polymer structures in polymer synthesis.

关键词： Additives Chemical structure Molecular structure Polymerization Polymers

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Dependence of the liquid crystalline properties on the exactly controlled single-site functionalized density of mesogens focused on the alternating copolymer model

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POLYMER CHEMISTRY 2021年第45期12卷 6561-6568页

作者： Zhang, Ruixue li, xuwen Ma, Hongwei Han, li li, Chao Zhang, Songbo Bai, Hongyuan li, Yang Dalian Univ Technol Sch Chem Engn Dept Polymer Sci & Engn State Key Lab Fine Chem Dalian 116024 Peoples R China

Fluorinated liquid crystal polymers (FLCPs) with an AB/A(2)B-alternating sequence of fluorinated biphenyl moieties (FMs) along their backbones were constructed, where the anionic copolymerization of isoprene (Ip) with, mono-SiH and di-SiH functionalized 1,1-diphenylethylene (DPE) derivatives was performed to prepare alternating copolymer precursors with exactly controlled single-site densities of -SiH, i.e., alt-P(D-S/Ip) and alt-P(D-2S/Ip), respectively, followed by highly efficient hydrosilylation to introduce FMs into the repeating unit (DPE). Previous work indicated that the mesogenic properties were related to the distance between neighbouring mesogenic moieties in different polymerized units when the degree of polymerization (DP) of the copolymers was low. Hence, the present strategy provides a novel model to explore dependence of the mesogenic properties on the exactly controlled single-site functionalized density of mesogens (FMs) for the resulting alternating-templated FLCPs, which was achieved due to a quite low DP (11 for mono-SiH and 5 for di-SiH), while exhibiting a similar overall concentration of FMs along backbones bearing a similar number of Si-H groups. The results show that the polarized optical textures and the temperature range of mesogenic phase formation (Delta T) varied remarkably between A(2)B-alternating (Delta T = 104 degrees C) and AB-alternating (Delta T = 23 degrees C) FLCPs;in particular, the variation in phase transition temperature is possibly a result of exactly controlled single-site functionalized density. Herein, a novel morphological aggregation model is proposed to increase the comprehension of how the exactly controlled single-site functionalized density of FMs arranged within the small scale of polymer chains directs molecular packing and interactions between them, thereby enriching the diversity of molecular interactions.

关键词： Silicon compounds

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A molecularly imprinted electrochemiluminescence sensor based on ZnO@CdTe for the detection of mevastatin

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MICROCHEMICAL JOURNAL 2024年 203卷

作者： li, Huiling Tian, li Yang, Shuning li, Chao li, Ruidan Song, Yujia Guo, Yanjia li, xuwen Changchun Normal Univ Coll chem Changchun 130032 Peoples R China Jilin Univ Coll Chem Changchun 130012 Peoples R China

In this paper, CdTe quantum dots with near-infrared fluorescence (NIR) and hexagonal prism-shaped ZnO were synthesized, and the composites were characterized for their performance. A sensitive molecularly imprinted electrochemiluminescence (ECL) sensor for the determination of mevastatin was constructed based on ZnO@CdTe and molecularly imprinted polymer (MIP). The highest ECL intensity of the system was obtained by ZnO@CdTe as the main luminophores reacted with the co-reactant K2S2O8. The ECL response generated by the reaction of ZnO@CdTe and K2S2O8 was used as the basic signal detection platform. The MIP was prepared by the electropolymerization process on the above platform, which laid the foundation for forming the mevastatin cavities with specific recognition sites. In addition, the response mechanism was investigated, and the determination conditions were optimized. The ECL intensity change values (Delta I) of the sensor showed a good linear relationship with the logarithm of mevastatin concentration in the range of 2.0 x 10-11 to 2.0 x 10-6 mol L-1, and the limit of detection was 6.7 x 10-12 mol L-1 (S/N = 3). This method obtained satisfactory results in the detection of mevastatin in tablets.

关键词： Molecularly-imprinted ZnO@CdTe Mevastatin Electrochemiluminescence

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Multi-Target Feeding-Behavior Recognition Method for Cows Based on Improved RefineMask

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SENSORS 2024年第10期24卷 2975页

作者： li, xuwen Gao, Ronghua li, Qifeng Wang, Rong liu, Shanghao Huang, Weiwei Yang, liuyiyi Zhuo, Zhenyuan Tianjin Agr Univ Coll Comp & Informat Engn Tianjin 300384 Peoples R China Beijing Acad Agr & Forestry Sci Res Ctr Informat Technol Beijing 100097 Peoples R China Northwest A&F Univ Coll Informat Engn Xianyang 712100 Peoples R China Beijing Univ Agr Coll Intelligent Sci & Engn Beijing 100096 Peoples R China

Within the current process of large-scale dairy-cattle breeding, to address the problems of low recognition-accuracy and significant recognition-error associated with existing visual methods, we propose a method for recognizing the feeding behavior of dairy cows, one based on an improved RefineMask instance-segmentation model, and using high-quality detection and segmentation results to realize the recognition of the feeding behavior of dairy cows. Firstly, the input features are better extracted by incorporating the convolutional block attention module into the residual module of the feature extraction network. Secondly, an efficient channel attention module is incorporated into the neck design to achieve efficient integration of feature extraction while avoiding the surge of parameter volume computation. Subsequently, the GIoU loss function is used to increase the area of the prediction frame to optimize the convergence speed of the loss function, thus improving the regression accuracy. Finally, the logic of using mask information to recognize foraging behavior was designed, and the accurate recognition of foraging behavior was achieved according to the segmentation results of the model. We constructed, trained, and tested a cow dataset consisting of 1000 images from 50 different individual cows at peak feeding times. The method's effectiveness, robustness, and accuracy were verified by comparing it with example segmentation algorithms such as MSRCNN, Point_Rend, Cascade_Mask, and ConvNet_V2. The experimental results show that the accuracy of the improved RefineMask algorithm in recognizing the bounding box and accurately determining the segmentation mask is 98.3%, which is higher than that of the benchmark model by 0.7 percentage points;for this, the model parameter count size was 49.96 M, which meets the practical needs of local deployment. In addition, the technologies under study performed well in a variety of scenarios and adapted to various light environment

关键词： RefineMask instance segmentation feeding behavior behavioral recognition

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Well-Tailored Dynamic liquid Crystal Networks with Anionically Polymerized Styrene-Butadiene Rubbers toward Modulating Shape Memory and Self-Healing Capacity

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MACROMOLECULES 2021年第6期54卷 2691-2702页

作者： Lei, Lan Han, li Ma, Hongwei Zhang, Ruixue li, xuwen Zhang, Songbo li, Chao Bai, Hongyuan li, Yang Dalian Univ Technol Sch Chem Engn State Key Lab Fine Chem Dept Polymer Sci & EngnLiaoning Key Lab Polymer Dalian 116024 Peoples R China

Well-tailored construction of liquid crystal networks (LCNs) with simultaneous molecular mobility and mechanical enhancement is desirable. Since the properties of polymeric materials are largely a result of the molecular compositions of polymer chains, in the present work, we demonstrate the tuning compositional synthesis of anionically polymerized random styrene-butadiene rubbers (r-SBRs) with well-controlled 75 wt % butadiene (Bd) contents that offer molecular mobility. Microstructural 1,2-olefins of 51.5-64.0 mol % were designed to attach 50 mol % SiH-terminated mesogenic moieties (M) along Bd units using hydrosilylation. As mechanical strength usually conflicts with high molecular mobility, an integrated design derived from the orderly LC stacking and simultaneous crosslinking in various ratios of the dynamic 2(6-isocyanatohexylaminocarbonylamino)-6methyl-4[1H]-pyrimidinone (UPy-NCO) and permanent hexamethylene diisocyanate (HMDI) along 1,4-olefins of Bd units offers necessary mechanical strength and molecular mobility, resulting in a series of dynamic LCNs (r-SBR-g-[***]). LC textures, phase transitions, self-healing/welding, and shape memory capacities were comprehensively studied. All LCNs showed LC textures in POM around T-i (42- 53 degrees C), which definitely contributed to both mechanical performance and molecular mobility due to the 50 mol % orderly LC stacking. Ureidopyrimidinone (UPy) that forms a dynamic H-bond is beneficial for the temporary shape fixity ratio (R-f), recyclability, and self-healing/welding ability while decreasing the shape recovery ratio (R-rec) because UPy can increase breaking elongations but sacrifice the mechanical strength. However, HMDI that forms a covalent crosslink showed the contrary effect, as HMDI can effectively enhance the mechanical strength but reduce the chain mobility. It is evidenced that r-SBR45k-g-[M-0%, 2%] can hardly undergo shape recovery (R-rec = 0) despite R-f = 92.6%, while with regard to r-SBR45k-g

关键词： Deformation Self healing materials Shape memory Differential scanning calorimetry liquid chromatography Chromatography

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Inhibitory activity of narirutin on RBL-2H3 cells degranulation

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IMMUNOPHARMACOLOGY AND IMMUNOTOXICOLOGY 2021年第1期43卷 68-76页

作者： Niu, liyan Wei, Jihao li, xuwen Jin, Yongri Shi, Xiaolei Jilin Univ Coll Food Sci & Engn Changchun Peoples R China Jilin Univ Coll Chem Changchun Peoples R China

Context: It is an efficient strategy to apply inhibition of mast cell degranulation for evaluating anti-allergic effects of compounds. Previous works confirmed that narirutin had anti-allergic activity in OVA induced allergic asthma murine model. However, the mechanism is not clear. Objective: Here, inhibitory mechanism of narirutin on RBL-2H3 cells degranulation was investigated. Materials and methods: Cell viability was analyzed by CCK-8 kits, cell degranulation was analyzed by EliSA methods, morphology and ultrastructure of cells was observed by atomic force microscopy, intracellular Ca (2+) concentration was measured by fluorescence microscopre, mRNA expression were measured by PCR, and signaling pathways were measured by WB. Results: The results showed that narirutin have no direct effects on mRNA expression of Fc epsilon RI subunit. However, it inhibited Ca2+ influx by suppressing the phosphorylation of Syk, LAT and PLC gamma 1 signaling pathway transduction. Subsequently, the inhibition of Ca2+ influx directly leads to NF-kappa B signaling pathway transduction decreased. Narirutin can also suppress the phosphorylation of MAPK signaling pathways by decreasing the expression of P-p38, P-ERK and P-JNK, inhibit the synergistic effect for Ca2+ influx, and then reduce the release of IL-4, TNF-alpha, histamine and beta-HEX. Conclusion: Our study suggested that the inhibitory mechanism of narirutin on RBL-2H3 cells degranulation could be related to regulate MAPK, NF-kappa B and Tyrosine kinase signaling pathway.

关键词： Allergy narirutin degranulation mechanism

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Low-level laser activates Wnt/β-catenin signaling pathway-promoting hair follicle stem cell regeneration and wound healing: Upregulate the expression of key downstream gene Lef 1

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SKIN RESEARCH AND TECHNOLOGY 2024年第6期30卷 e13807页

作者： BangHong, Jiang YuKun, Wang Ao, Shi Tao, Sun PeiJun, Song xuwen, li lin, li ZhuYou, Xiong li, Zhang Bengbu Med Coll Affiliated Hosp 1 Dept Plast Surg Bengbu Peoples R China Lanzhou Univ Hosp & Clin Med Sch 2 Lanzhou Peoples R China Bengbu Med Coll Affiliated Hosp 1 Dept Neurosurg Bengbu Peoples R China

BackgroundThe objective of this study is to investigate the mechanism by which low-level laser stimulation promotes the proliferation of intraepithelial hair follicle stem cells (HFSCs) in wounds. This research aims to expand the applications of laser treatment, enhance wound repair methods, and establish a theoretical and experimental foundation for achieving accelerated wound *** experimental approach involved irradiating a cell model with low-level laser to assess the proliferation of HFSCs and examine alterations in the expression of proteins related to the Wnt/beta-catenin signaling pathway. A mouse back wound model was established to investigate the effects of low-level laser irradiation on wound healing rate, wound microenvironment, and the proliferation of HFSCs in relation to the Wnt/beta-catenin signaling *** research findings indicate that low-level laser light effectively activates the Wnt signaling pathway, leading to the increased accumulation of core protein beta-catenin and the upregulation of key downstream gene Lef 1. Consequently, this regulatory mechanism facilitates various downstream biological effects, including the notable promotion of HFSC proliferation and differentiation into skin appendages and epithelial tissues. As a result, the process of wound healing is significantly *** levels of laser activates the Wnt signalling pathway, promotes the regeneration of hair follicle stem cells and accelerates wound healing.

关键词： carcinogenesis low-level laser stem cells Wnt/beta-catenin pathway wound healing

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Microenvironment-tailored micelles restrain carcinoma-astrocyte crosstalk for brain metastasis

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JOURNAL OF CONTROLLED RELEASE 2022年 349卷 520-532页

作者： Zhao, Zhenhao Zhang, Yujie li, Chao li, xuwen Chu, Yongchao Guo, Qin Zhang, Yiwen Xia, Weiyi liu, Peixin Chen, Hongyi Wang, Yu li, Chufeng Sun, Tao Jiang, Chen Fudan Univ Sch Pharm Dept Pharmaceut Key Lab Smart Drug Delivery Shanghai 201203 Peoples R China Fudan Univ MOE Frontiers Ctr Brain Sci Shanghai 201203 Peoples R China

Breast-to-brain metastatic cells can interact with the surrounding cells, including astrocytes and microglia, to generate a pro-tumorigenic niche. Breast-to-brain metastasis can be treated using a dual strategy of eliminating metastatic tumor cells and normalizing their localized microenvironment. The effective accumulation of drugs at the action site of metastasis is crucial to realizing the above strategy, especially when dealing with the bloodbrain barrier (BBB)-penetrating and tumor-targeting tactics. Here, we establish an in-situ microenvironmenttailored micelle (T-M/siRNA) to co-deliver therapeutic siRNA and paclitaxel (PTX) into the breast-to-brain metastasis. Anchored with a D-type cyclic peptide, T-M/siRNA can penetrate the BBB and subsequently target the brain metastases. Upon internalization by metastatic tumor cells, T-M/siRNA can release PTX in the highlevel glutathione (GSH), resulting in killing cancer cells. Meanwhile, the micellar structure is dissociated, resulting in lowering the charge density to release the loaded siRNA that can targeted downregulate the expression of protocadherin 7 (PCDH7). Treatment of model mice revealed that T-M/siRNA can inhibit the abnormal activation of astrocytes and immunosuppressive activation of microglia, resulting in significantly enhanced synergistic anti-tumor efficacy. This study indicates that the micelle system can serve as a hopeful strategy to treat breast-to-brain metastasis.

关键词： Breast -to -brain metastasis Micelle Microenvironment Protocadherin 7 Paclitaxel

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XCO2 Super-Resolution Reconstruction Based on Spatial Extreme Random Trees

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ATMOSPHERE 2024年第4期15卷 440页

作者： li, xuwen Jiang, Sheng Wang, Xiangyuan Wang, Tiantian Zhang, Su Guo, Jinjin Jiao, Donglai Jiangsu Prov Environm Monitoring Ctr Nanjing 210019 Peoples R China Nanjing Univ Posts & Telecommun Sch Internet Things Nanjing 210023 Peoples R China

Carbon dioxide (CO2) is currently the most harmful greenhouse gas in the atmosphere. Obtaining long-term, high-resolution atmospheric column CO2 concentration (XCO2) datasets is of great practical significance for mitigating the greenhouse effect, identifying and controlling carbon emission sources, and achieving carbon cycle management. However, mainstream satellite observations provide XCO2 datasets with coarse spatial resolution, which is insufficient to support the needs of higher-precision research. To address this gap, in this study, we integrate spatial information with the extreme random trees model and develop a new machine learning model called spatial extreme random trees (SExtraTrees) to reconstruct a 1 km spatial resolution XCO2 dataset for China from 2016 to 2020. The results indicate that the predictive ability of spatial extreme random trees is more stable and has higher fitting accuracy compared to other methods. Overall, XCO2 in China shows an increasing trend year by year, with the spatial distribution revealing significantly higher XCO2 levels in eastern coastal regions compared to western inland areas. The contributions of this study are primarily in the following areas: (1) Considering the spatial heterogeneity of XCO2 and combining spatial features with the advantages of machine learning, we construct the spatial extreme random trees model, which is verified to have high predictive accuracy. (2) Using the spatial extreme random trees model, we reconstruct high-resolution XCO(2 )datasets for China from 2016 to 2020, providing data support for carbon emission reduction and related decision making. (3) Based on the generated dataset, we analyze the spatiotemporal distribution patterns of XCO2 in China, thereby improving emission reduction policies and sustainable development measures.

关键词： XCO2 spatial downscaling SExtraTrees high resolution spatial features

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