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12,717 results on '"Chen, Kun"'

352. Determination of pesticide residue in soil samples by molecularly imprinted solid-phase extraction method

Author

Yu Xiaofeng, Xie Jiawei, Yan Bixing, Song Renyuan, Chen Kun, and Yan Hegang

Subjects
porous molecularly imprinted polymer, lenacil, template molecule, Polymers and polymer manufacture, TP1080-1185
Abstract

Porous molecularly imprinted polymer (MIP) microspheres were synthesized via iniferter-suspension polymerization method, employing lenacil (LA) as the template molecule and methacrylic acid (MAA) as the functional monomer. The host–guest complexes formed using LA and MAA were characterized by hydrogen nuclear magnetic resonance and ultraviolet–visible absorption spectroscopy. The obtained results showed that the interaction between LA and MAA mainly relied on hydrogen bonding. The surface morphologies and chemical structures of the MIPs were characterized by scanning electron microscopy. MIPs were spherical in shape with a relatively regular sphericity, rough surface structure, and numerous small holes, which significantly reduced the mass transfer resistance of the template molecules and exhibited excellent recognition performance for template molecules. In addition, soil samples were pretreated with solid-phase extraction columns molecularly imprinted with LA, and analyzed by high-performance liquid chromatography. The recoveries of LA, bromacil, and terbacil were up to 89.65%, 53.17%, and 44.63%, respectively. The developed method showed a minimum detection limit of 10–50 µg·mL−1. In view of the continuous increase of public requirements for pesticide residue detection, a versatile pretreatment method was developed that is green, rapid, simple, and can be miniaturized.

Published
2024
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358. Finite-size Scaling of O($n$) Systems at the Upper Critical Dimensionality

Author

Lv, Jian-Ping, Xu, Wanwan, Sun, Yanan, Chen, Kun, and Deng, Youjin

Subjects
Condensed Matter - Statistical Mechanics, Condensed Matter - Strongly Correlated Electrons
Abstract

Logarithmic finite-size scaling of the O($n$) universality class at the upper critical dimensionality ($d_c=4$) has a fundamental role in statistical and condensed-matter physics and important applications in various experimental systems. Here, we address this long-standing problem in the context of the $n$-vector model ($n=1, 2, 3$) on periodic four-dimensional hypercubic lattices. We establish an explicit scaling form for the free energy density, which simultaneously consists of a scaling term for the Gaussian fixed point and another term with multiplicative logarithmic corrections. In particular, we conjecture that the critical two-point correlation $g(r,L)$, with $L$ the linear size, exhibits a two-length behavior: following the behavior $r^{2-d_c}$ governed by Gaussian fixed point at shorter distance and entering a plateau at larger distance whose height decays as $L^{-d_c/2}({\rm ln}L)^{\hat{p}}$ with $\hat{p}=1/2$ a logarithmic correction exponent. Using extensive Monte Carlo simulations, we provide complementary evidence for the predictions through the finite-size scaling of observables including the two-point correlation, the magnetic fluctuations at zero and non-zero Fourier modes, and the Binder cumulant. Our work sheds light on the formulation of logarithmic finite-size scaling and has practical applications in experimental systems., Comment: 8+6 pages, 4+3 figures

Published
2019
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362. Quantum-to-classical correspondence in two-dimensional Heisenberg models

Author

Wang, Tao, Cai, Xiansheng, Chen, Kun, Prokof'ev, Nikolay V., and Svistunov, Boris V.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

The quantum-to-classical correspondence (QCC) in spin models is a puzzling phenomenon where the static susceptibility of a quantum system agrees with its classical-system counterpart, at a different corresponding temperature, within the systematic error at a sub-percent level. We employ the bold diagrammatic Monte Carlo method to explore the universality of QCC by considering three different two-dimensional spin-1/2 Heisenberg models. In particular, we reveal the existence of QCC in two-parametric models., Comment: 4 pages, 4figures

Published
2019
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373. Single-molecule displacement mapping unveils nanoscale heterogeneities in intracellular diffusivity

Author

Xiang, Limin, Chen, Kun, Yan, Rui, Li, Wan, and Xu, Ke

Subjects
Biochemistry and Cell Biology, Biological Sciences, 1.1 Normal biological development and functioning, Underpinning research, Cell Nucleus, Cells, Cultured, Cytoplasm, Diffusion, Humans, Image Interpretation, Computer-Assisted, Intracellular Space, Microscopy, Fluorescence, Models, Theoretical, Nanoparticles, Proteins, Single Molecule Imaging, Technology, Medical and Health Sciences, Developmental Biology, Biological sciences
Abstract

Intracellular diffusion underlies vital cellular processes. However, it remains difficult to elucidate how an unbound protein diffuses inside the cell with good spatial resolution and sensitivity. Here we introduce single-molecule displacement/diffusivity mapping (SMdM), a super-resolution strategy that enables the nanoscale mapping of intracellular diffusivity through local statistics of the instantaneous displacements of freely diffusing single molecules. We thus show that the diffusion of an average-sized protein in the mammalian cytoplasm and nucleus is spatially heterogeneous at the nanoscale, and that variations in local diffusivity correlate with the ultrastructure of the actin cytoskeleton and the organization of the genome, respectively. SMdM of differently charged proteins further unveils that the possession of positive, but not negative, net charges drastically impedes diffusion, and that the rate is determined by the specific subcellular environments. We thus unveil rich heterogeneities and charge effects in intracellular diffusion at the nanoscale.

Published
2020

374. Comparison of two different types of hybrid Tibial fixations for anterior cruciate ligament reconstruction: a prospective comparative cohort study

Author

Po-Jen Lai, Chin-Chean Wong, Wen-Pei Chang, Chen-Kun Liaw, Chih-Hwa Chen, and Pei-Wei Weng

Subjects
Anterior cruciate ligament reconstruction, Tunnel widening, Tunnel enlargement, Hamstring graft, Hybrid fixation, Adjustable suspensory device, Diseases of the musculoskeletal system, RC925-935
Abstract

Abstract Background Previous studies have compared different kinds of fixations for anterior cruciate ligament reconstruction. Nevertheless, there is no optimal method to date. To the best of authors’ knowledge, there is no article discussing the combination of adjustable suspensory device and interference screw for hybrid tibial fixation. Methods In total, 66 patients (n = 34, adjustable suspensory device and interference screw; n = 32, cortical screw and interference screw) were analyzed. Their International Knee Documentation Committee score and Tegner activity level scale were evaluated before and after a 2-year follow-up. The Single Assessment Numeric Evaluation score was evaluated after a 2-year follow-up. Physical exams such as range of motion, anterior knee pain (VAS > = 3) and Lachman test were assessed before and at least 12 months after surgery. To evaluate tunnel widening, anteroposterior and lateral view radiography was conducted 1 day and at least 12 months after surgery. A more than 10% change was considered tibial tunnel widening. Mann–Whitney U test, independent t test, paired t test, Fisher’s exact test and chi-squared test were used to compare the variables. Linear and logistic regression models were applied to adjust for potential confounders. Results No variable except gender (P = 0.006) showed significant difference with regard to demographic data. After adjustment, there was no statistically significant difference between the groups regarding post-operative physical exams. Patients who used adjustable suspensory device and interference screw had lower post-operative Single Assessment Numeric Evaluation score (adjusted β − 8.194; P = 0.017), Tegner activity level scale (adjusted β − 1.295; P = 0.001) and pre-operative degrees of knee flexion (adjusted β − 2.825; P = 0.026). Less percentage of tunnel widening in the lateral view of radiographs was seen in patients in group of adjustable suspensory device and interference screw (adjusted β − 1.733; P = 0.038). No significant difference was observed in the anteroposterior view of radiographs (adjusted β − 0.667; P = 0.26). Conclusion In these 66 patients, we observed less tibial tunnel widening and lower post-operative functional scores in the group of adjustable suspensory device and interference screw. Both groups displayed similar outcomes of physical exams as well as improvement after operation. The proposed method may become an alternative option. Nonetheless, the quality of our study is still limited, and thus further studies are warranted to determine the efficacy and further application. Trial registration Joint Institutional Review Board of Taipei Medical University, Taipei, Taiwan (No: N201805094 ). Study design Prospective comparative cohort study; Level of evidence, II.

Published
2022
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394. Integrated Multi-Omics Landscape of Liver Metastases

Author

Yang, Shuai, Qian, Ling, Li, Zhixuan, Li, Ye, Bai, Jian, Zheng, Bo, Chen, Kun, Qiu, Xinyao, Cai, Guoxiang, Wang, Shan, Huang, Haiyan, Wu, Jianmin, Zhu, Yanjing, Zhangyang, Qianwen, Feng, Lanyun, Wu, Tong, Wu, Rui, Yang, Airong, Wang, Kaiting, Wang, Ruiru, Zhang, Yani, Zhao, Yan, Wang, Wenwen, Bao, Jinxia, Shen, Siyun, Hu, Ji, Wu, Xuan, Zhou, Tao, Meng, Zhiqiang, Liu, Weiwei, Wang, Hongyang, Wang, Peng, and Chen, Lei

Published
2023
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