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  1. Article ; Online: The spatiotemporal evolution and influencing factors of hotel industry in the metropolitan area

    Lei Li / Lin Lu / Yuchen Xu / Xiaolong Sun

    PLoS ONE, Vol 15, Iss 5, p e

    An empirical study based on China.

    2020  Volume 0231438

    Abstract: Through the online booking platform, 10,543 big data of spatial and temporal distribution of Beijing hotel industry has been obtained in this paper. Then, the methods of GIS and the geographical detector are used to study the spatiotemporal evolution ... ...

    Abstract Through the online booking platform, 10,543 big data of spatial and temporal distribution of Beijing hotel industry has been obtained in this paper. Then, the methods of GIS and the geographical detector are used to study the spatiotemporal evolution process and the influencing factors of Beijing hotel industry during 2003-2018. The results are as follows: a. During the period of 2003-2018, the hotel industry in Beijing maintained a high growth rate and had three growth peaks in 2008, 2010 and 2014. Meanwhile, major historical events, such as the Olympic Games had a significant influence on the development of the hotel industry. b. Between 2003 and 2018, the hotel industry in Beijing gradually developed from the centripetal agglomeration to aggregation + diffusion, and also from the single center to the multi-center. Besides, various hotels presented two characteristics of city orientation and scenic orientation. c. The natural geographical environment had shaped the overall pattern and characteristics of the spatial distribution of the hotel industry in Beijing, and the socio-economic factors such as commercial activities, public facilities, tourism services and traffic conditions significantly influenced the location selection of the hotel industry. Therefore, the urban center is the ideal area for the spatial layout of the hotel industry. d. Geographical detector research showed that the factors, such as administrative organs, road network density, leisure and recreational facilities, and companies have strong explanatory power for hotel location selection, which is an important reference index for hotels to select the micro location. This paper is a beneficial supplement to the existing research and has certain guiding significance for the sustainable development of Beijing hotel industry.
    Keywords Medicine ; R ; Science ; Q
    Subject code 910
    Language English
    Publishing date 2020-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: The impact of microplastic pollution on ecological environment

    Xi Mao / Yuchen Xu / Zhong Cheng / Yunbo Yang / Zetang Guan / Lu Jiang / Kai Tang

    Frontiers in Bioscience-Landmark, Vol 27, Iss 2, p

    a review

    2022  Volume 046

    Abstract: Microplastic pollution and its impact on the ecological environment have attracted worldwide attention. The strong adsorption capacity of the microplastic surface plays an important role in the migration of microplastics throughout the environment. ... ...

    Abstract Microplastic pollution and its impact on the ecological environment have attracted worldwide attention. The strong adsorption capacity of the microplastic surface plays an important role in the migration of microplastics throughout the environment. Synergistic effects between microplastics and persistent organic pollutants increase the toxicity of pollutants to organisms. In addition, microplastics cause different degrees of harm to aquatic organisms with different nutritional levels. However, the toxic effects of microplastics and organic pollutants on organisms, the distribution of microplastics in higher aquatic organisms, and the nutrient transfer in complex aquatic food webs require further research. Therefore, studying the impact of microplastics on the ecological environment would provide insights into controlling microplastic pollution. This paper in-depth discusses the source, distribution, and transmission of microplastics and summarizes the current situation of the impact of microplastics on the ecological environment, including physical, chemical, and biological effects. This paper also suggests topics for further research on the influence of microplastics on various aspects of the ecological environment.
    Keywords aquatic organism ; ecological environment ; microplastic ; microplastic pollution ; water environment ; Biochemistry ; QD415-436 ; Biology (General) ; QH301-705.5
    Subject code 333
    Language English
    Publishing date 2022-01-01T00:00:00Z
    Publisher IMR Press
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Measurement of ferric iron in Chang’e-5 impact glass beads

    Lixin Gu / Yangting Lin / Yongjin Chen / Yuchen Xu / Xu Tang / Sen Hu / Ho-kwang Mao / Jinhua Li

    Earth, Planets and Space, Vol 75, Iss 1, Pp 1-

    2023  Volume 10

    Abstract: Abstract The lunar surface and interior are highly reducing, resulting in the virtually absence of ferric ion. However, recent studies suggest the presence of ferric iron in lunar samples, and in most cases they were found in amorphous silicates (e.g., ... ...

    Abstract Abstract The lunar surface and interior are highly reducing, resulting in the virtually absence of ferric ion. However, recent studies suggest the presence of ferric iron in lunar samples, and in most cases they were found in amorphous silicates (e.g., glass beads) measured by TEM–EELS. In this work, we conducted a systematic TEM–EELS analysis on the iron valence states of Chang’e-5 impact glass beads. The Fe3+/ΣFe ratio of each silicate glass sample was determined from integral intensity of Fe L3 and L2 edge. The measurements show a positive correlation between the dwell time and Fe3+/ΣFe ratio, which reveals that ferric iron can be significantly produced by electron beam bombardment under routine analytical condition. The calculated Fe3+/ΣFe with short dwell times (≤ 20 ms) in our Chang’e-5 impact glass beads show no detectable inherent ferric iron, suggesting that the ferric iron is not ubiquitous as previously reported. It is obvious that a careful control of experiment conditions is critical to determine the inherent redox state of other beam-sensitive terrestrial and extraterrestrial samples. Graphical Abstract
    Keywords Lunar soils ; Chang’e-5 ; Ferric iron ; EELS ; Beam damage ; Geography. Anthropology. Recreation ; G ; Geodesy ; QB275-343 ; Geology ; QE1-996.5
    Language English
    Publishing date 2023-10-01T00:00:00Z
    Publisher SpringerOpen
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Development and external validation of a nomogram for predicting renal function based on preoperative data from in-hospital patients with simple renal cysts

    Yiding Chen / Lei Chen / Jialin Meng / Meng Zhang / Yuchen Xu / Song Fan / Chaozhao Liang / Guiyi Liao

    Journal of International Medical Research, Vol

    2022  Volume 50

    Abstract: Objective To develop and validate a nomogram for predicting renal dysfunction in patients with simple renal cysts (SRCs). Methods We performed a multivariable logistic regression analysis of an in-hospital retrospective cohort of patients with SRCs in ... ...

    Abstract Objective To develop and validate a nomogram for predicting renal dysfunction in patients with simple renal cysts (SRCs). Methods We performed a multivariable logistic regression analysis of an in-hospital retrospective cohort of patients with SRCs in the Urology Department of the First Affiliated Hospital of Anhui Medical University. For prognostic model development, 386 patients with SRCs were enrolled from January 2016 to December 2018. External validation was performed in 46 patients with SRCs from January 2019 to April 2019. The primary outcome was renal dysfunction. Results Patients were divided into normal or abnormal estimated glomerular filtration rate groups (293 vs. 93) based on the cut-off value of 90 mL/minute/1.73 m 2 . Logistical regression analysis determined that age, haemoglobin, globulin, and creatinine might be associated with renal dysfunction, and a novel nomogram was established. Calibration curves showed that the true prediction rate was 77.42%, and decision curve analysis revealed that the nomogram was more effective with threshold probabilities ranging from 0.1 to 0.8. The area under the curves were 0.829, 0.752, and 0.888 in the overall training, internal, and external validation cohorts, respectively. Conclusions We established a nomogram to predict the probability of developing renal dysfunction in patients with SRCs.
    Keywords Medicine (General) ; R5-920
    Subject code 616
    Language English
    Publishing date 2022-03-01T00:00:00Z
    Publisher SAGE Publishing
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Combination of focused ion beam (FIB) and microtome by ultrathin slice preparation for transmission electron microscopy (TEM) observation

    Yuchen Xu / Lixin Gu / Yang Li / Bing Mo / Yangting Lin

    Earth, Planets and Space, Vol 70, Iss 1, Pp 1-

    2018  Volume 6

    Abstract: Abstract There are growing demands for integrated study of isotopes, trace elements and crystallography of micron-sized grains observed on polished sections or scattered on surface of sample holders. However, transmission electron microscopy (TEM) ... ...

    Abstract Abstract There are growing demands for integrated study of isotopes, trace elements and crystallography of micron-sized grains observed on polished sections or scattered on surface of sample holders. However, transmission electron microscopy (TEM) observation is largely restricted by the challenges associated with the preparation of ultrathin sections from given micron-sized grains after chemical and isotopic analyses. Here, we report a new method of combining focused ion beam (FIB) and microtome techniques. This method is demonstrated by the successful preparation of several ultrathin slices from a presolar graphite grain. The presolar graphite grain was a spherule with a diameter of 5 μm. It was found by nanoscale secondary ion mass spectrometry (NanoSIMS) mapping of a carbonaceous acid residue from the Qingzhen enstatite chondrite (EH3), deposited on a gold foil mount. The spherule showed isotope anomalies in C and Si, with 12C/13C = 99 ± 2 and δ29Si/28Si = 172 ± 36‰, and likely originated in an asymptotic branch giant (AGB) star. After NanoSIMS analysis, this spherule was transported and fixed on a pre-cut top surface of an epoxy stub, using FIB. The fixed spherule was then embedded entirely in resin, and cut into ~ 70 nm slices with a microtome. TEM observation of these ultrathin sections revealed a turbostratic structure free of any subgrains. The morphology, Raman spectrum, C and Si isotopic compositions, internal texture and crystallography of this graphite spherule suggest that it condensed from a carbon-rich outflow of an AGB star.
    Keywords Focused ion beam ; Transmission electron microscopy ; Microtome ; Presolar grains ; Graphite ; Geography. Anthropology. Recreation ; G ; Geodesy ; QB275-343 ; Geology ; QE1-996.5
    Subject code 669
    Language English
    Publishing date 2018-09-01T00:00:00Z
    Publisher SpringerOpen
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Human Sensation of Transcranial Electric Stimulation

    Fan-Gang Zeng / Phillip Tran / Matthew Richardson / Shuping Sun / Yuchen Xu

    Scientific Reports, Vol 9, Iss 1, Pp 1-

    2019  Volume 12

    Abstract: Abstract Noninvasive transcranial electric stimulation is increasingly being used as an advantageous therapy alternative that may activate deep tissues while avoiding drug side-effects. However, not only is there limited evidence for activation of deep ... ...

    Abstract Abstract Noninvasive transcranial electric stimulation is increasingly being used as an advantageous therapy alternative that may activate deep tissues while avoiding drug side-effects. However, not only is there limited evidence for activation of deep tissues by transcranial electric stimulation, its evoked human sensation is understudied and often dismissed as a placebo or secondary effect. By systematically characterizing the human sensation evoked by transcranial alternating-current stimulation, we observed not only stimulus frequency and electrode position dependencies specific for auditory and visual sensation but also a broader presence of somatic sensation ranging from touch and vibration to pain and pressure. We found generally monotonic input-output functions at suprathreshold levels, and often multiple types of sensation occurring simultaneously in response to the same electric stimulation. We further used a recording circuit embedded in a cochlear implant to directly and objectively measure the amount of transcranial electric stimulation reaching the auditory nerve, a deep intercranial target located in the densest bone of the skull. We found an optimal configuration using an ear canal electrode and low-frequency (<300 Hz) sinusoids that delivered maximally ~1% of the transcranial current to the auditory nerve, which was sufficient to produce sound sensation even in deafened ears. Our results suggest that frequency resonance due to neuronal intrinsic electric properties need to be explored for targeted deep brain stimulation and novel brain-computer interfaces.
    Keywords Medicine ; R ; Science ; Q
    Subject code 610
    Language English
    Publishing date 2019-10-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article: Facile synthesis of perfluoroalkylated fluorenes via a one-pot two-step three-component process

    Sun, Zhenhua / Qi Huang / Jing Han / Weimin He / Jie Chen / Yuchen Xu / Hongmei Deng / Min Shao / Hui Zhang / Weiguo Cao

    Tetrahedron. 2018 Apr. 19, v. 74, no. 16

    2018  

    Abstract: The efficient synthesis of perfluoroalkyl-substituted fluorenes directly from indenones, malononitrile and methyl perfluoroalk-2-ynoates via a one-pot two-step three-component cascade process is reported. Up to 12 examples of indenones with various ... ...

    Abstract The efficient synthesis of perfluoroalkyl-substituted fluorenes directly from indenones, malononitrile and methyl perfluoroalk-2-ynoates via a one-pot two-step three-component cascade process is reported. Up to 12 examples of indenones with various substituents were converted into their corresponding functionalized fluorene derivatives in good to excellent yields.
    Keywords chemical reactions ; chemical structure ; fluorenes
    Language English
    Dates of publication 2018-0419
    Size p. 2073-2078.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 204285-x
    ISSN 1464-5416 ; 0040-4020 ; 0563-2064
    ISSN (online) 1464-5416
    ISSN 0040-4020 ; 0563-2064
    DOI 10.1016/j.tet.2018.03.012
    Database NAL-Catalogue (AGRICOLA)

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  8. Article ; Online: Canonical Wnt inhibitors ameliorate cystogenesis in a mouse ortholog of human ADPKD

    Ao Li / Yuchen Xu / Song Fan / Jialin Meng / Xufeng Shen / Qian Xiao / Yuan Li / Li Zhang / Xiansheng Zhang / Guanqing Wu / Chaozhao Liang / Dianqing Wu

    JCI Insight, Vol 3, Iss

    2018  Volume 5

    Abstract: Autosomal dominant polycystic kidney disease (ADPKD) can be caused by mutations in the PKD1 or PKD2 genes. The PKD1 gene product is a Wnt cell-surface receptor. We previously showed that a lack of the PKD2 gene product, PC2, increases β-catenin signaling ...

    Abstract Autosomal dominant polycystic kidney disease (ADPKD) can be caused by mutations in the PKD1 or PKD2 genes. The PKD1 gene product is a Wnt cell-surface receptor. We previously showed that a lack of the PKD2 gene product, PC2, increases β-catenin signaling in mouse embryonic fibroblasts, kidney renal epithelia, and isolated renal collecting duct cells. However, it remains unclear whether β-catenin signaling plays a role in polycystic kidney disease phenotypes or if a Wnt inhibitor can halt cyst formation in ADPKD disease models. Here, using genetic and pharmacologic approaches, we demonstrated that the elevated β-catenin signaling caused by PC2 deficiency contributes significantly to disease phenotypes in a mouse ortholog of human ADPKD. Pharmacologically inhibiting β-catenin stability or the production of mature Wnt protein, or genetically reducing the expression of Ctnnb1 (which encodes β-catenin), suppressed the formation of renal cysts, improved renal function, and extended survival in ADPKD mice. Our study clearly demonstrates the importance of β-catenin signaling in disease phenotypes associated with Pkd2 mutation. It also describes the effects of two Wnt inhibitors, XAV939 and LGK974, on various Wnt signaling targets as a potential therapeutic modality for ADPKD, for which there is currently no effective therapy.
    Keywords Genetics ; Medicine ; R
    Subject code 616
    Language English
    Publishing date 2018-03-01T00:00:00Z
    Publisher American Society for Clinical investigation
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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