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419 results on '"Liu, Guanhua"'

1. Weak parabolic Harnack inequality and H\'older regularity for non-local Dirichlet forms

Author

Liu, Guanhua

Subjects
Mathematics - Analysis of PDEs, 34K30 (Primary) 31C25, 35K08, 47D07, 60J46 (Secondary)
Abstract

In this paper we give equivalent conditions for the weak parabolic Harnack inequality for general regular Dirichlet forms without killing part, in terms of local heat kernel estimates or growth lemmas. With a tail estimate on the jump measure, we obtain from these conditions the H\"older continuity of caloric and harmonic functions. Our results generalize the theory of Chen, Kumagai and Wang, in the sense that the upper jumping smoothness condition is canceled. We also derive the complete forms of Harnack inequalities from the globally non-negative versions, and obtain continuity of caloric functions with worse tails.

Published
2024

2. A Novel Shortest Path Query Algorithm Based on Optimized Adaptive Topology Structure

Author

Fang, Xiao, Song, Xuyang, Ma, Jiyuan, Liu, Guanhua, Pang, Shurong, Zhao, Wenbo, Cao, Cong, and Fan, Ling

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

Urban rail transit is a fundamental component of public transportation, however, commonly station-based path search algorithms often overlook the impact of transfer times on search results, leading to decreased accuracy. To solve this problem, this paper proposes a novel shortest path query algorithm based on adaptive topology optimization called the Adaptive Topology Extension Road Network Structure (ATEN). This algorithm categorizes transfer stations into different types and treats travel time and transfer time equivalently as weights for edges in the topological graph. The proposed algorithm introduces virtual stations to differentiate between pedestrian paths and train paths, eliminating the need for additional operations on transfer stations. The algorithm controls the extent of expansion in the urban rail transit topology, overcoming query errors caused by mishandling of transfer stations in the existing algorithm. Finally, a series of simulation experiments were conducted on Beijing's urban rail transit network to validate both correctness and efficiency of the proposed adaptive topology optimization algorithm. The results demonstrate significant advantages compared to existing similar algorithms.

Published
2024

4. Heat kernel estimates on local and non-local Dirichlet spaces satisfying a weak chain condition

Author

Liu, Guanhua

Subjects
Mathematics - Probability, Mathematics - Analysis of PDEs
Abstract

In this paper, we focus on the heat kernel estimates for diffusions and jump processes on metric measure spaces satisfying a weak chain condition, where the length of a nearly shortest $\varepsilon$-chain between two points $x,y$ is comparable with a function of $d(x,y)$ and $\varepsilon$. For a diffusion, the best estimate is already given by Grigor'yan and Telcs, and we make it explicit in our particular case. For jump processes, especially those where the scale of the process is different with that of the jump kernel, we improve the results by Bae, Kang, Kim and Lee. Uniformity of the coefficients (or parameters) in the known estimates and metric transforms play the key role in our proof. We also show by examples how the weak chain condition is valid in practice.

Published
2023
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11. On the comparison between jump processes and subordinated diffusions

Author

Liu, Guanhua and Murugan, Mathav

Subjects
Mathematics - Probability, 31E05, 31C25, 47D07, 60J25
Abstract

Given a symmetric diffusion process and a jump process on the same underlying space, is there a subordinator such that the jump process and the subordinated diffusion processes are comparable? We address this question when the diffusion satisfies a sub-Gaussian heat kernel estimate and the jump process satisfies a polynomial-type jump kernel bounds. Under these assumptions, we obtain necessary and sufficient conditions on the jump kernel estimate for such a subordinator to exist. As an application of our results and the recent stability results of Chen, Kumagai, and Wang, we obtain parabolic Harnack inequality for a large family of jump processes. In particular, we show that any jump process with polynomial-type jump kernel bounds on such a space satisfies the parabolic Harnack inequality., Comment: 13 pages

Published
2021

19. Parabolic Harnack inequality implies the existence of jump kernel

Author

Liu, Guanhua and Murugan, Mathav

Subjects
Mathematics - Probability, Mathematics - Analysis of PDEs
Abstract

We prove that the parabolic Harnack inequality implies the existence of jump kernel for symmetric pure jump process. This allows us to remove a technical assumption on the jumping measure in the recent characterization of the parabolic Harnack inequality for pure jump processes by Chen, Kumagai and Wang. The key ingredients of our proof are the L\'evy system formula and a near-diagonal heat kernel lower bound., Comment: 11 pages; comments welcome

Published
2020

32. CmMYC2–CmMYBML1 module orchestrates the resistance to herbivory by synchronously regulating the trichome development and constitutive terpene biosynthesis in Chrysanthemum.

Author

Guan, Yaqin, Jiang, Li, Wang, You, Liu, Guanhua, Wu, Jiayi, Luo, Hong, Chen, Sumei, Chen, Fadi, Niinemets, Ülo, Chen, Feng, and Jiang, Yifan

Subjects
SPODOPTERA littoralis, TRICHOMES, PLANT species, DATABASES, TERPENES
Abstract

Summary: Trichomes are specialized epidermal outgrowths covering the aerial parts of most terrestrial plants. There is a large species variability in occurrence of different types of trichomes such that the molecular regulatory mechanism underlying the formation and the biological function of trichomes in most plant species remain unexplored.Here, we used Chrysanthemum morifolium as a model plant to explore the regulatory network in trichome formation and terpenoid synthesis and unravel the physical and chemical roles of trichomes in constitutive defense against herbivore feeding.By analyzing the trichome‐related genes from transcriptome database of the trichomes‐removed leaves and intact leaves, we identified CmMYC2 to positively regulate both development of T‐shaped and glandular trichomes as well as the content of terpenoids stored in glandular trichomes. Furthermore, we found that the role of CmMYC2 in trichome formation and terpene synthesis was mediated by interaction with CmMYBML1. Our results reveal a sophisticated molecular mechanism wherein the CmMYC2–CmMYBML1 feedback inhibition loop regulates the formation of trichomes (non‐glandular and glandular) and terpene biosynthesis, collectively contributing to the enhanced resistance to Spodoptera litura larvae feeding.Our findings provide new insights into the novel regulatory network by which the plant synchronously regulates trichome density for the physical and chemical defense against herbivory. [ABSTRACT FROM AUTHOR]

Published
2024
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33. Rhodium complex-anchored and supramolecular polymer-grafted CdS nanoflower for enhanced photosynthesis of H2O2 and photobiocatalytic C-H bond oxyfunctionalization.

Author

Jia, Hongwei, Yue, Xiaoyang, Hou, Yuying, Huang, Fei, Cao, Cuiyao, Jia, Feifei, Liu, Guanhua, Zheng, Xiaobing, Liu, Yunting, and Jiang, Yanjun

Abstract

Unspecific peroxygenases exhibit high activity for the selective oxyfunctionalization of inert C(sp3)-H bonds using only H2O2 as a clean oxidant, while also exhibiting sensitivity to H2O2 concentration. CdS-based semiconductors are promising for the photosynthesis of H2O2 owing to their adequately negative potential for oxygen reduction reaction via a proton-coupled electron transfer process, however, they suffer from fast H2O2 decomposition on the surface of pristine CdS. Therefore, [Cp*Rh(bpy)H2O]2+, a highly selective proton-coupled electron transfer catalyst, was anchored onto a supramolecular polymer-grafted CdS nanoflower to construct an efficient integrated photocatalyst for generating H2O2, mitigating the surface issue of pristine CdS, increasing light absorption, accelerating photonic carrier separation, and enhancing oxygen reduction reaction selectivity to H2O2. This photocatalyst promoted the light driven H2O2 generation rate up to 1345 µmol·L−1·g−1·h−1, which was 2.4 times that of pristine CdS. The constructed heterojunction photocatalyst could supply H2O2in situ for nonspecific peroxygenases to catalyze the C-H oxyfunctionalization of ethylbenzene, achieving a yield of 81% and an ee value of 99% under optimum conditions. A wide range of substrates were converted to the corresponding chiral alcohols using this photo-enzyme catalytic system, achieving the corresponding chiral alcohols in good yield (51%–88%) and excellent enantioselectivity (90%–99% ee). [ABSTRACT FROM AUTHOR]

Published
2024
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44. Molecular Engineering and Morphology Control of Covalent Organic Frameworks for Enhancing Activity of Metal‐Enzyme Cascade Catalysis.

Author

Zhao, Hao, Zhang, Jialin, Liu, Yunting, Liu, Xinlong, Ma, Li, Zhou, Liya, Gao, Jing, Liu, Guanhua, Yue, Xiaoyang, and Jiang, Yanjun

Subjects
AUTOMATIC control systems, CATALYSIS, BINDING sites, CATALYTIC activity, KINETIC resolution, FUNCTIONAL groups
Abstract

Metal‐enzyme integrated catalysts (MEICs) that combine metal and enzyme offer great potential for sustainable chemoenzymatic cascade catalysis. However, rational design and construction of optimal microenvironments and accessible active sites for metal and enzyme in individual nanostructures are necessary but still challenging. Herein, Pd nanoparticles (NPs) and Candida antarctica lipase B (CALB) are co‐immobilized into the pores and surfaces of covalent organic frameworks (COFs) with tunable functional groups, affording Pd/COF‐X/CALB (X = ONa, OH, OMe) MEICs. This strategy can regulate the microenvironment around Pd NPs and CALB, and their interactions with substrates. As a result, the activity of the COF‐based MEICs in catalyzing dynamic kinetic resolution of primary amines is enhanced and followed COF‐OMe > COF‐OH > COF‐ONa. The experimental and simulation results demonstrated that functional groups of COFs modulated the conformation of CALB, the electronic states of Pd NPs, and the affinity of the integrated catalysts to the substrate, which contributed to the improvement of the catalytic activity of MEICs. Further, the MEICs are prepared using COF with hollow structure as support material, which increased accessible active sites and mass transfer efficiency, thus improving catalytic performance. This work provides a blueprint for rational design and preparation of highly active MEICs. [ABSTRACT FROM AUTHOR]

Published
2024
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46. Plant‐derived monoterpene S‐linalool and β‐ocimene generated by CsLIS and CsOCS‐SCZ are key chemical cues for attracting parasitoid wasps for suppressing Ectropis obliqua infestation in Camellia sinensis L

Author

Liu, Guanhua, primary, Wang, Qian, additional, Chen, Hui, additional, Wang, Yuxi, additional, Zhou, Xiaogui, additional, Bao, Demeng, additional, Wang, Nuo, additional, Sun, Juan, additional, Huang, Fuyin, additional, Yang, Mei, additional, Zhang, Han, additional, Yan, Peng, additional, Li, Xin, additional, Shi, Jiang, additional, and Fu, Jianyu, additional

Published
2024
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50. The water lily genome and the early evolution of flowering plants

Author

Zhang, Liangsheng, Chen, Fei, Zhang, Xingtan, Li, Zhen, Zhao, Yiyong, Lohaus, Rolf, Chang, Xiaojun, Dong, Wei, Ho, Simon Y. W., Liu, Xing, Song, Aixia, Chen, Junhao, Guo, Wenlei, Wang, Zhengjia, Zhuang, Yingyu, Wang, Haifeng, Chen, Xuequn, Hu, Juan, Liu, Yanhui, Qin, Yuan, Wang, Kai, Dong, Shanshan, Liu, Yang, Zhang, Shouzhou, Yu, Xianxian, Wu, Qian, Wang, Liangsheng, Yan, Xueqing, Jiao, Yuannian, Kong, Hongzhi, Zhou, Xiaofan, Yu, Cuiwei, Chen, Yuchu, Li, Fan, Wang, Jihua, Chen, Wei, Chen, Xinlu, Jia, Qidong, Zhang, Chi, Jiang, Yifan, Zhang, Wanbo, Liu, Guanhua, Fu, Jianyu, Chen, Feng, Ma, Hong, Van de Peer, Yves, and Tang, Haibao

Published
2020
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