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Impact of oxygen supply on production of terpenoids by microorganisms: State of the art

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Chinese Journal of Chemical Engineering 2021年第2期34卷 46-53页

作者： ting-ting liu Han Xiao Jian-Hui Xiao Jian-Jiang Zhong State Key Laboratory of Microbial Metabolism Joint International Research Laboratory of Metabolic and Developmental SciencesLaboratory of Molecular Biochemical Engineering and Advanced Fermentation TechnologyDepartment of BioengineeringSchool of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China Zunyi Municipal Key Laboratory of Medicinal Biotechnology Center for Translational MedicineAffiliated Hospital of Zunyi Medical UniversityZunyi 563003China

Terpenoids are a class of high value-added natural products with a variety of biological *** engineered microorganisms,such as those of Escherichia coli and Saccharomyces cerevisiae,have merits in producing plant or fungus-derived terpenoids,due to their mature genetic manipulation,simple nutrient demand and fast ***,as a key environmental factor,is particularly important to microbial metabolism and growth,and suitable oxygen supply is viewed as a prerequisite for realizing highly efficient production of terpenoids by engineered *** this article,the role of oxygen in regulating terpenoid bioproduction is overviewed from the viewpoints of cellular carbon metabolism,energy metabolism and terpenoid *** on adjusting oxygen availability to microorganisms,including genetic modification of cellular metabolism related with oxygen utilization,are summarized and discussed,to provide helpful information for further improvement of terpenoid biosynthesis by microbes.

关键词： Terpenoid Microorganisms Oxygen supply Chassis modification

A Gaussian copula regression model for movie box-office revenues prediction

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Science China(Information Sciences) 2017年第9期60卷 36-49页

作者： Junwen DUAN Xiao DING ting liu Research Center for Social Computing and Information Retrieval Harbin Institute of Technology

In this article, we revisit the task of movie box-office revenues prediction using multi-type *** movie box-office revenues are affected by numerous factors. Previous work with discriminative models assumes these factors are identically and independently distributed. The correlations between these factors are rarely considered, which limited the performances of discriminative models in this task. To address these problems, we investigate a novel Gaussian copula regression model. Based on this model, we do not need to make any prior assumptions about the marginal distributions of the features. In particular, we perform a cumulative probability estimation on each of the smoothed features. The estimation learns the marginal distributions and maps all features into a uniform vector space. Sequentially, we bridge the marginal distributions with a copula function to create their joint distribution, and learn the dependency structure between them. Moreover, we propose a computational-efficient approximate algorithm for responsible variable inference. Experimental results on two movie datasets from Chinese and U.S. market show that our approach outperforms strong discriminative regression baselines.

关键词： Gaussian copula movie box-office revenue multi-variate regression text regression social media

A language-independent neural network for event detection

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Science China(Information Sciences) 2018年第9期61卷 81-92页

作者： Xiaocheng FENG Bing QIN ting liu Computer Science and Technology Harbin Institute of Technology

Event detection remains a challenge because of the difficulty of encoding the word semantics in various contexts. Previous approaches have heavily depended on language-specific knowledge and preexisting natural language processing tools. However, not all languages have such resources and tools available compared with English language. A more promising approach is to automatically learn effective features from data, without relying on language-specific resources. In this study, we develop a language-independent neural network to capture both sequence and chunk information from specific contexts and use them to train an event detector for multiple languages without any manually encoded features. Experiments show that our approach can achieve robust, efficient and accurate results for various languages. In the ACE 2005 English event detection task, our approach achieved a 73.4% F-score with an average of 3.0% absolute improvement compared with state-of-the-art. Additionally, our experimental results are competitive for Chinese and Spanish.

关键词： nature language processing event detection neural networks representation learning

The impact of depositional environment and tectonic evolution on coalbed methane occurrence in West Henan, China

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International Journal of Mining Science and Technology 2019年第2期29卷 297-305页

作者： Zhaodan Cao Baiquan Lin ting liu China University of Mining and Technology Department of Energy and Mineral Engineering The Pennsylvania State University University Park

A deeper understanding of the mechanisms by which geological factors(depositional environment and tectonic evolution) control the occurrence of coalbed methane(CBM) is important for the utilization of CBM resources via surface-drilled wells and the elimination of coal-methane outbursts, the latter of which is a key issue for coal mine safety. Based on drill core data, high-pressure isothermal adsorption experiments, scanning electron microscopy experiments, mercury intrusion porosimetry, and X-ray diffraction experiments, the impact of the depositional environment and tectonic evolution on CBM occurrence of the II-1 coal seam of the Shanxi Formation in West Henan was analyzed. Results showed that the depositional environment led to the epigenetic erosion of tidal flat coal-accumulating structures by shallow-delta distributary channel strata. This resulted in the replacement of the original mudstonesandy mudstone coal seam immediate roof with fine-to-medium grained sandstones, reducing methane storage capacity. Epigenetic erosion by the depositional environment also increased coal body ash content(from 6.9% to 21.4%) and mineral content, filling the cleat system and reducing porosity, reducing methane storage capacity. The maximum methane adsorption capacity of the coal body reduced from35.7 cm3/g to 30.30 cm3/g, and Langmuir pressure decreased from 1.39 MPa to 0.909 MPa. Hence, the methane adsorption capacity of the coal body decreased while its capacity for methane desorption increased. Owing to the tectonic evolution of West Henan, tectonically deformed coal is common; as it evolves from primary cataclastic coal to granulitic coal, the angle of the diffraction peak increases, d002 decreases, and La, Lc, and Nc increase; these traits are generally consistent with dynamic *** is accompanied by increases in the total pore volume and specific surface area of the coal body, further increasing the capacity for methane storage. Increases in micropore volume

关键词： Coalbed methane Depositional environment Tectonic evolution Epigenetic erosion Tectonically-deformed coal

Encoding syntactic representations with a neural network for sentiment collocation extraction

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Science China(Information Sciences) 2017年第11期60卷 7-18页

作者： Yanyan ZHAO Bing QIN ting liu Department of Media Technology and Art Harbin Institute of Technology Department of Computer Science and Technology Harbin Institute of Technology

Sentiment collocation refers to the collocation of a target word and a polarity word. Sentiment collocation extraction aims to extract the targets and their modifying polarity words by analyzing the relationships between them. This can be regarded as a basic sentiment analysis task and is relevant in many practical applications. Previous studies relied mainly on the syntactic path, which is used to connect the target word and the polarity word. To deeply exploit the semantic information of the syntactic path, we propose two types of syntactic representation, namely, relation embedding and subtree embedding, to capture the latent semantic features. Relation embedding is used to represent the latent semantics between targets and their corresponding polarity words, and subtree embedding is used to explore the rich syntactic information for each word on the path. To combine the two types of syntactic representations, a neural network is constructed. We use a recursive neural network(RNN) to model the subtree embeddings, and then the subtree embedding and the word embedding are combined as the enhanced word representation for each word in the syntactic path. Finally,a convolutional neural network(CNN) is adopted to integrate the two types of syntactic representations to extract the sentiment collocations from reviews. Our experiments were conducted on six types of reviews, which included product domains(such as cameras and phones) and service domains(such as hotels and restaurants).The experimental results show that our proposed method can accurately capture the latent semantic features hidden behind the syntactic paths that neither the common feature-based methods nor the syntactic-path-based method can handle, and, further, that it significantly outperforms numerous baselines and previous methods.

关键词： sentiment collocation extraction sentiment analysis syntactic representation neural network re cursive neural network(RNN) convolutional neural network(CNN)

DNA End Resection:Facts and Mechanisms

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Genomics, Proteomics & Bioinformatics 2016年第3期14卷 126-130页

作者： ting liu Jun Huang Department of Cell Biology and Program in Molecular Cell Biology Zhejiang University School of Medicine Life Sciences Institute and Innovation Center for Cell Signaling Network Zhejiang University

DNA double-strand breaks（DSBs）,which arise following exposure to a number of endogenous and exogenous agents,can be repaired by either the homologous recombination（HR）or non-homologous end-joining（NHEJ） pathways in eukaryotic cells.A vital step in HR repair is DNA end resection,which generates a long 30single-stranded DNA（ss DNA） tail that can invade the homologous DNA *** generation of 30 ss DNA is not only essential for HR repair,but also promotes activation of the ataxia telangiectasia and Rad3-related protein（ATR）.Multiple factors,including the MRN/X complex,C-terminal-binding protein interacting protein（Ct IP）/Sae2,exonuclease 1（EXO1）,Bloom syndrome protein（BLM）/Sgs1,DNA2 nuclease/helicase,and several chromatin remodelers,cooperate to complete the process of end *** we review the basic machinery involved in DNA end resection in eukaryotic cells.

关键词： DNA end resection Homologous recombination DNA double-strand breaks Chromatin remodeling factors Genome stability

Mining spatiotemporal patterns of urban dwellers from taxi trajectory data

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Frontiers of Earth Science 2016年第2期10卷 205-221页

作者： FengMAO Minhe JI ting liu The GIScience Key Lab Education Ministry of China East China Normal University Shanghai 200241 China Research Center for East-West Cooperation in China East China Normal University Shanghai 200241 China Institute of Remote Sensing and Earth Science Hangzhou Normal University Hangzhou 310036 China

With the widespread adoption of location- aware technology, obtaining long-sequence, massive and high-accuracy spatiotemporal trajectory data of individuals has become increasingly popular in various geographic studies. Trajectory data of taxis, one of the most widely used inner-city travel modes, contain rich information about both road network traffic and travel behavior of passengers. Such data can be used to study the microscopic activity patterns of individuals as well as the macro system of urban spatial structures. This paper focuses on trajectories obtained from GPS-enabled taxis and their applications for mining urban commuting patterns. A novel approach is proposed to discover spatiotemporal patterns of household travel from the taxi trajectory dataset with a large number of point locations. The approach involves three critical steps： spatial clustering of taxi origin-destination （OD） based on urban traffic grids to discover potentially meaningful places, identifying thresh- old values from statistics of the OD clusters to extract urban jobs-housing structures, and visualization of analytic results to understand the spatial distribution and temporal trends of the revealed urban structures and implied household commuting behavior. A case study with a taxi trajectory dataset in Shanghai, China is presented to demonstrate and evaluate the proposed method.

关键词： taxi trajectory spatial clustering spatiotem-poral pattern mining

Mechanical criterion for coal and gas outburst:a perspective from multiphysics coupling

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International Journal of Coal Science & Technology 2021年第6期8卷 1423-1435页

作者： ting liu Baiquan Lin Xuehai Fu Ang liu School of Safety Engineering China University of Mining&TechnologyXuzhou 221116China Key Laboratory of CBM Resources and Dynamic Accumulation Process China University of Mining&TechnologyXuzhou 221008China Department of Energy and Mineral Engineering G3 Center and EMS Energy InstituteThe Pennsylvania State UniversityUniversity ParkPAUSA

Although a series of hypotheses have been proposed,the mechanism underlying coal and gas outburst remains *** the low-index outbursts encountered in mining practice,we attempt to explore this mechanism using a multiphysics coupling model considering the effects of coal strength and gas mass transfer on *** on force analysis of coal ahead of the heading face,a risk identification index C_(m)and a critical criterion(C_(m)≥1)of coal instability are *** to this criterion,the driving force of an outburst consists of stress and gas pressure gradients along the heading direction of the roadway,whereas resistance depends on the shear and tensile strengths of the *** results show that outburst risk decreases slightly,followed by a rapid increase,with increasing vertical stress,whereas it decreases with increasing coal strength and increases with gas pressure *** the response surface method,a coupled multi-factor model for the risk identification index is *** results indicate strong interactions among the controlling ***,the critical values of the factors corresponding to outburst change depending on the environment of the coal seams,rather than being *** the buried depth of a coal seam increases,the critical values of gas pressure and coal strength decrease slightly,followed by a rapid *** to its controlling factors,outburst can be divided into stress-dominated,coal-strength-dominated,gas-pressure-dominated,and multi-factor compound *** on this classification,a classified control method is proposed to enable more targeted outburst prevention.

关键词： Coal and gas outburst Critical criterion Multiphysics coupling Response surface method

Evaluation of groundwater geochemical characteristics and quality in the central and Northern Shaanxi Province,China

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Acta Geochimica 2020年第5期39卷 733-740页

作者： Hui Yan Jun Xiao ting liu Yujie liu College of Urban-Rural Planning and Landscape ArchitectureXuchang UniversityXuchang 461000China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment.Chinese Academy of SciencesXi'an 710061China CAS Center for Excellenee in Quaternary Science and Global Change Xi'an 710061China College of Geomatics Xi'an University of Science and TechnologyXi'an 710054.China

Groundwater is of vital importance to many aspects of ecosystem services,especially in the central and northern Shaanxi Provence,China,-an area covered by loess deposits and short of water *** studied the solute geochemistry and water quality of groundwater in this area to improve the understanding of hydrogeochemical processes in loess deposits *** results showed that the average pH of groundwaters was 8.03±0.36(1 SD)with large ranges(324-83,379 mg/L)of the total dissolved solids(TDS).The cations and anions followed the order of Na^+>Ca^2+>Mg^2+>K^+>SiO2 and HCO3>Cl^->SO4^2->F^->NO3^-.Most groundwater samples show the HCO3^--Na^+-Ca^2+water type and a small number of samples the Na^+-Cl^-*** water quality assessments showed that 40%of the groundwater has good water quality,42%moderate water quality,and 18%(the upper reaches of Wuding River and Wei River)poor water quality with very high *** 40%of groundwater samples were not suitable for drinking due to the high TDS,fluoride,sulfide,and *** plot and stoichiometry analysis showed that carbonate weathering is the main source of groundwater chemistry in central Shaanxi Province while evaporite dissolution dominates in northern Shaanxi *** loess weathering significantly influences the dissolved solutes of groundwater in the Loess *** ion-exchange between Mg^2+and Ca^2+in groundwater and Na^+in clay minerals and the deposition of carbonate minerals increased Na^+but decreased the Ca^2+in *** research results improve our understanding of hydrogeochemical processes that affect the solutes chemistry of groundwater in the loess area and provide essential data to the global groundwater database.

关键词： Geochemical characteristics Hydrochemical process Groundwater quality Central and northern Shaanxi