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Evaluating Different Methods for Estimating Diameter at Breast Height from Terrestrial Laser Scanning

Chang Liu, Yanqiu Xing, Jialong Duanmu, Xin Tian
2018 Remote Sensing  
Yanqiu Xing and Xin Tian assisted with data collection. Yanqiu Xing secured funding for the project, provided valuable suggestions for the overall design of the study, and reviewed the manuscript.  ... 
doi:10.3390/rs10040513 fatcat:nhpjtdxrbzhgpod7gao4eimhqy

Synthesis and Anti-Tumor Activities of Ring A Derived Analogues of Oleanolic Acid

Yanqiu Meng, Wen Xing, Zhenyu Kuai, Weichen Zhang, Wei Li
2017 Youji huaxue  
doi:10.6023/cjoc201610033 fatcat:ov4hz2chinggjpnmkyrkhyvbky

Annular Neighboring Points Distribution Analysis: A Novel PLS Stem Point Cloud Preprocessing Algorithm for DBH Estimation

Jialong Duanmu, Yanqiu Xing
2020 Remote Sensing  
Personal laser scanning (PLS) has significant potential for estimating the in-situ diameter of breast height (DBH) with high efficiency and precision, which improves the understanding of forest structure and aids in building carbon cycle models in the big data era. PLS collects more complete stem point cloud data compared with the present laser scanning technology. However, there is still no significant advantage of DBH estimation accuracy. Because the error caused by merging different point
more » ... ud fragments has not yet been eliminated, overlapping and inaccurate co-registered point cloud fragments are often inevitable, which are usually the leading error sources of PLS-based DBH estimation. In this study, a novel pre-processing algorithm named annular neighboring points distribution analysis (ANPDA) was developed to improve PLS-based DBH estimation accuracy. To reduce the impact of inaccurately co-registered point cloud fragments, ANPDA identified outliers through iterative removal of outermost points and analyzing the distribution of annular neighboring points. Six plots containing 247 trees under different forest conditions were selected to evaluate the ANPDA. Results showed that in the six plots, error reductions of 53.80–87.13% for bias, 38.82–57.30% for mean absolute error (MAE), and 27.17–56.02% for root mean squared error (RMSE) were achieved after applying ANPDA. These results confirmed that ANPDA was generally effective for improving PLS-based DBH estimation accuracy. It appeared that ANPDA could be conveniently fused with an automatic PLS-based DBH estimation process as a preprocessing algorithm. Furthermore, it has the potential to predict and warn operators of potential large errors during hierarchical semi-automatic DBH estimation.
doi:10.3390/rs12050808 fatcat:zqvnxxgbjbegtp6os7jb6kbdzi

Investigation of the Dynamic Recrystallization of FeMnSiCrNi Shape Memory Alloy under Hot Compression Based on Cellular Automaton

Yu Wang, Xiaodong Xing, Yanqiu Zhang, Shuyong Jiang
2019 Metals  
Dynamic recrystallization (DRX) takes place when FeMnSiCrNi shape memory alloy (SMA) is subjected to compression deformation at high temperatures. Cellular automaton (CA) simulation was used for revealing the DRX mechanism of FeMnSiCrNi SMA by predicting microstructures, grain size, flow stress, and dislocation density. The DRX of FeMnSiCrNi SMA has a characteristic of repeated nucleation and finite growth. The size of recrystallized grains increases with increasing deformation temperatures,
more » ... it decreases with increasing strain rates. The increase of deformation temperature leads to the decrease of the flow stress, whereas the increase in strain rate results in the increase of the flow stress. The dislocation density exhibits the same situation as the flow stress. The simulated results were supported by the experimental ones very well. Dislocation density is a crucial factor during DRX of FeMnSiCrNi SMA. It affects not only the nucleation but also the growth of the recrystallized grains. Occurrence of DRX depends on a critical dislocation density. The difference between the dislocation densities of the recrystallized and original grains becomes the driving force for the growth of the recrystallized grains, which lays a solid foundation for the recrystallized grains growing repeatedly.
doi:10.3390/met9040469 fatcat:dhzmrkd3ezasthubjwvjsd4xqy

Quantifying the Effects of Normalisation of Airborne LiDAR Intensity on Coniferous Forest Leaf Area Index Estimations

Haotian You, Tiejun Wang, Andrew Skidmore, Yanqiu Xing
2017 Remote Sensing  
The range between a sensor and the target, the incidence angle, and the target reflectance, are known factors that can influence the intensity values of LiDAR data and consequently, its use in many applications. However, very few studies have provided a quantitative analysis of the effects of normalisation of these three factors on forest leaf area index (LAI) estimations. In this paper, using two coniferous tree species (i.e., Scotch pine and Larch pine) as a case study, the effects of
more » ... y normalisation on coniferous forest LAI estimations have, for the first time, been systematically examined and quantified. It was found that the intensity normalisation had a generally positive effect on the improvement of coniferous forest LAI estimations. However, the improvements were very minor. Specifically, the range normalisation did not improve the accuracy of the LAI estimation for either of the two coniferous tree species. The incidence angle and reflectance normalisation improved the accuracy of the LAI estimation for Scotch pine forests; however, they had no effect on the improvement of the LAI estimation for Larch pine forests. This experimental study suggests that range normalisation is not required for forest LAI estimations in areas with small elevation differences (i.e., less than 114 m). The incidence angle and target reflectance normalisation can marginally improve the accuracy of coniferous forest LAI estimations. However, the extent of this improvement varies among species, depending on the choice of incidence angle and reflectance coefficient. Overall, the effects of normalisation of airborne LiDAR intensity on coniferous forest LAI estimations are closely related to topographic conditions (i.e., elevation and slope), the tree species composition, and its associated structural attributes. Therefore, further research should explore the effects of LiDAR intensity normalisation on forest LAI estimations in regions with large elevation differences and diverse forest structures.
doi:10.3390/rs9020163 fatcat:n4pa64hl5nc57dc226o7tsxy7i

Particle Swarm Optimization-Based Noise Filtering Algorithm for Photon Cloud Data in Forest Area

Jiapeng Huang, Yanqiu Xing, Haotian You, Lei Qin, Jing Tian, Jianming Ma
2019 Remote Sensing  
The Ice, Cloud, and land Elevation Satellite-2 (ICESat-2), which is equipped with the Advanced Topographic Laser Altimeter System (ATLAS), was launched successfully in 15 September 2018. The ATLAS represents a micro-pulse photon-counting laser system, which is expected to provide more comprehensive and scientific data for carbon storage. However, the ATLAS system is sensitive to the background noise, which poses a tremendous challenge to the photon cloud noise filtering. Moreover, the Density
more » ... sed Spatial Clustering of Applications with Noise (DBSCAN) is a commonly used algorithm for noise removal from the photon cloud but there has not been an in-depth study on its parameter selection yet. This paper presents an automatic photon cloud filtering algorithm based on the Particle Swarm Optimization (PSO) algorithm, which can be used to optimize the two key parameters of the DBSCAN algorithm instead of using the manual parameter adjustment. The Particle Swarm Optimization Density Based Spatial Clustering of Applications with Noise (PSODBSCAN) algorithm was tested at different laser intensities and laser pointing types using the MATLAS dataset of the forests located in Virginia, East Coast, and the West Coast, USA. The results showed that the PSODBSCAN algorithm and the localized statistical algorithm were effective in identifying the background noise and preserving the signal photons in the raw MATLAS data. Namely, the PSODBSCAN achieved the mean F value of 0.9759, and the localized statistical algorithm achieved the mean F value of 0.6978. For both laser pointing types and laser intensities, the proposed algorithm achieved better results than the localized statistical algorithm. Therefore, the PSODBSCAN algorithm could support the MATLAS photon cloud data noise filtering applicably without manually selecting parameters.
doi:10.3390/rs11080980 fatcat:yyjkbkqgbfeohixvkcbzmcyjj4

RGS22 inhibits pancreatic adenocarcinoma cell migration through the G12/13 α subunit/F-actin pathway

YANQIU HU, JUN XING, LING CHEN, YING ZHENG, ZUOMIN ZHOU
2015 Oncology Reports  
Pancreatic cancer is characterized by the potential for local invasion, allowing it to spread during the early developmental stages of the disease. Regulator of G protein signaling 22 (RGS22) localizes to the cytoplasm in pancreatic adenocarcinoma tissue. We overexpressed RGS22 in the human pancreatic cancer cell line BXPC-3. Cells that overexpressed RGS22 had much lower wound-healing rates and greatly reduced migration compared to the control cells. Conversely, cells in which RGS22 expression
more » ... ad been downregulated had higher wound-healing rates and migration than the control cells. These results confirmed that RGS22 expression suppresses pancreatic adenocarcinoma cell migration. Pull-down and coimmunoprecipitation assays revealed that RGS22 had specific interactions with the heterotrimeric G protein G12 α subunit (GNA12) and GNA13 in the cells. We also demonstrated that in the presence of higher RGS22 expression, the cell deformation and F-actin formation caused by lysophosphatidic acid treatment, is delayed. Constitutively active Gα subunits did not accelerate GTP hydrolysis to GDP. We did not investigate the function of RGS22 as a negative regulator of heterotrimeric G12/13 protein signaling. Our data demonstrate that RGS22 acts as a tumor suppressor, repressing human pancreatic adenocarcinoma cell migration by coupling to GNA12/13, which in turn leads to inhibition of stress fiber formation.
doi:10.3892/or.2015.4209 pmid:26323264 fatcat:xcrl5tlvizaddlpufpmwln6mwa

Ultralight 3D-γ-MnOOH porous materials fabricated by hydrothermal treatment and freeze-drying

Yanqiu Wang, Lu Chen, Min Chen, Zhaoxiang Zhong, Qingwei Meng, Weihong Xing
2018 Science China Materials  
Yanqiu  ...  Author contributions Xing W and Zhong Z conceived and designed the experiments; Wang Y, Chen L, Chen M, Meng Q carried out the experiments. Wang Y and Zhong Z wrote this paper.  ... 
doi:10.1007/s40843-018-9352-7 fatcat:xgzzlt5rrjdfdoqert272xvwve

Intermittent Fasting Protects against Alzheimer's Disease Possible through Restoring Aquaporin-4 Polarity

Jingzhu Zhang, Zhipeng Zhan, Xinhui Li, Aiping Xing, Congmin Jiang, Yanqiu Chen, Wanying Shi, Li An
2017 Frontiers in Molecular Neuroscience  
The impairment of amyloid-β (Aβ) clearance in the brain plays a causative role in Alzheimer's disease (AD). Polarity distribution of aquaporin-4 (AQP4) is important to remove Aβ from brain. AQP4 polarity can be influenced by the ratio of two AQP4 isoforms M1 and M23 (AQP4-M1/M23), however, it is unknown whether the ratio of AQP4-M1/M23 changes in AD. Histone deacetylase 3 has been reported to be significantly increased in AD brain. Moreover, evidence indicated that microRNA-130a (miR-130a)
more » ... bly mediates the regulation of histone deacetylase 3 on AQP4-M1/M23 ratio by repressing the transcriptional activity of AQP4-M1 in AD. This study aimed to investigate whether intermittent fasting (IF), increasing the level of an endogenous histone deacetylases inhibitor β-hydroxybutyrate, restores AQP4 polarity via miR-130a mediated reduction of AQP4-M1/M23 ratio in protection against AD. The results showed that IF ameliorated cognitive dysfunction, prevented brain from Aβ deposition, and restored the AQP4 polarity in a mouse model of AD (APP/PS1 double-transgenic mice). Additionally, IF down-regulated the expression of AQP4-M1 and histone deacetylase 3, reduced AQP4-M1/M23 ratio, and increased miR-130a expression in the cerebral cortex of APP/PS1 mice. In vitro, β-hydroxybutyrate was found to down-regulate the expression of AQP4-M1 and histone deacetylase 3, reduce AQP4-M1/M23 ratio, and increase AQP4-M23 and miR-130a expression in 2 µM Aβ-treated U251 cells. Interestingly, on the contrary to the result observed in 2 µM Aβ-treated cells, AQP4 expression was obviously decreased in cells exposed to 10 µM Aβ. miR-130a mimic decreased the expression of AQP4-M1 and the ratio of AQP4-M1/M23, as well as silencing histone deacetylase 3 caused the up-regulation of AQP4 and miR-130a, and the reduction of AQP4-M1/M23 ratio in U251 cells. In conclusion, IF exhibits beneficial effects against AD. The mechanism may be associated with recovery of AQP4 polarity, resulting from the reduction of AQP4-M1/M23 ratio. Furthermore, β-hydroxybutyrate may partly mediate the effect of IF on the reduction of AQP4-M1/M23 ratio in AD, in which miR-130a and histone deacetylase 3 may be implicated.
doi:10.3389/fnmol.2017.00395 pmid:29238290 pmcid:PMC5712566 fatcat:tqlcj4h6knh2jevvqodmrwtoai

Upregulation of miR-26b alleviates morphine tolerance by inhibiting BDNF via Wnt/β-catenin pathway in rats

Xing Liu, Jiefeng Geng, Huilian Bu, Junqi Ma, Yanqiu Ai
2019 RSC Advances  
Morphine is a commonly used analgesic drug. However, long-term use of morphine will cause tolerance which limits its clinical application in pain treatment.
doi:10.1039/c9ra06264e pmid:35540064 pmcid:PMC9076454 fatcat:y573vryw25blzgt34bwd5t6cwm

Co-Administration of Multiple Childhood Vaccines - Guangdong Province, 2019

Hai Li, Yanqiu Tan, Haiying Zeng, Fengmei Zeng, Xing Xu, Yu Liao, Qi Zhu, Meng Zhang, Xuguang Chen, Min Kang, Fujie Xu, Huizhen Zheng
2020 China CDC Weekly  
What is already known about this topic?
pmid:34594611 pmcid:PMC8422173 fatcat:mqmwvz4dfnfezev5txptiqxey4

Effects of Different LiDAR Intensity Normalization Methods on Scotch Pine Forest Leaf Area Index Estimation

YOU Haotian, XING Yanqiu, PENG Tao, DING Jianhua
2018 Acta Geodaetica et Cartographica Sinica  
The intensity data of airborne light detection and ranging (LiDAR) are affected by many factors during the acquisition process. It is of great significance for the normalization and application of LiDAR intensity data to study the effective quantification and normalization of the effect from each factor. In this paper, the LiDAR data were normalized with range, angel of incidence, range and angle of incidence based on radar equation, respectively. Then two metrics, including canopy intensity
more » ... and ratio of intensity, were extracted and used to estimate forest LAI, which was aimed at quantifying the effects of intensity normalization on forest LAI estimation. It was found that the range intensity normalization could improve the accuracy of forest LAI estimation. While the angle of incidence intensity normalization did not improve the accuracy and made the results worse. Although the range and incidence angle normalized intensity data could improve the accuracy, the improvement was less than the result of range intensity normalization. Meanwhile, the differences between the results of forest LAI estimation from raw intensity data and normalized intensity data were relatively big for canopy intensity sum metrics. However, the differences were relatively small for the ratio of intensity metrics. The results demonstrated that the effects of intensity normalization on forest LAI estimation were depended on the choice of affecting factor, and the influential level is closely related to the characteristics of metrics used. Therefore, the appropriate method of intensity normalization should be chosen according to the characteristics of metrics used in the future research, which could avoid the waste of cost and the reduction of estimation accuracy caused by the introduction of inappropriate affecting factors into intensity normalization.
doi:10.11947/j.agcs.2018.20170515 doaj:66232dd7aa9a41eea1ff0283b29f8f1c fatcat:w3fjqr2ndndtpowyzv6twmvp2e

Assessing the Performance of ICESat-2/ATLAS Multi-Channel Photon Data for Estimating Ground Topography in Forested Terrain

Yanqiu Xing, Jiapeng Huang, Armin Gruen, Lei Qin
2020 Remote Sensing  
As a continuation of Ice, Cloud, and Land Elevation Satellite-1 (ICESat-1), the ICESat-2/Advanced Topographic Laser Altimeter System (ATLAS) employs a micro-pulse multi-beam photon counting approach to produce photon data for measuring global terrain. Few studies have assessed the accuracy of different ATLAS channels in retrieving ground topography in forested terrain. This study aims to assess the accuracy of measuring ground topography in forested terrain using different ATLAS channels and
more » ... correlation between laser intensity parameters, laser pointing angle parameters, and elevation error. The accuracy of ground topography measured by the ATLAS footprints is evaluated by comparing the derived Digital Terrain Model (DTM) from the ATL03 (Global Geolocated Photon Data) and ATL08 (Land and Vegetation Height) products with that from the airborne Light Detection And Ranging (LiDAR). Results show that the ATLAS product performed well in the study area at all laser intensities and laser pointing angles, and correlations were found between the ATLAS DTM and airborne LiDAR DTM (coefficient of determination––R2 = 1.00, root mean squared error––RMSE = 0.75 m). Considering different laser intensities, there is a significant correlation between the tx_pulse_energy parameter and elevation error. With different laser pointing angles, there is no significant correlation between the tx_pulse_skew_est, tx_pulse_width_lower, tx_pulse_width_upper parameters and the elevation error.
doi:10.3390/rs12132084 fatcat:5eyxar4dz5chbelldxfccfhbla

Heat Accumulation Mechanism of the Gaoyang Carbonatite Geothermal Field, Hebei Province, North China

Baojian Zhang, Siqi Wang, Fengxin Kang, Yanqiu Wu, Yanyan Li, Jun Gao, Wenzhen Yuan, Yifei Xing
2022 Frontiers in Earth Science  
From 2019 to 2021, we constructed two high-productivity geothermal wells with wellhead temperatures of 109.2 and 123.4°C in the Gaoyang geothermal field. Based on the two wells, it was proved that Gaoyang is a medium-temperature carbonate geothermal field with great development potential. The article reported the latest exploration achievements of deep buried hill geothermal resources in the geothermal field. The productivity of D34 and D35 geothermal wells were evaluated by James end-pressure
more » ... ethod: the total flow of steam–water mixture was 234.59–331.92 (t/h), the dryness was 1.36–2.03%, and the single-well power generation potential was 2.10–2.55 MW. Combined with those results, the heat control factors and heat accumulation mechanism of the deep carbonatite geothermal field were confirmed. The westward subduction of the Pacific plate caused obvious damage to the eastern North China Craton and greatly reduced the thickness of the lithosphere and crust. This process facilitated the conduction of mantle-derived heat to shallow crust. Deep strike-slip faults (e.g., Maxi fault) cut through the lithosphere, leading the deep mantle-derived heat and magma to migrate into the crust. The heat accumulated from the depression with low thermal conductivity to the uplift with high thermal conductivity. Groundwater was heated up by deep cycle and convection along faults. The catchment of regional karst groundwater also had a certain effect on the heat accumulation. The Gaoyang geothermal field was formed by these factors.
doi:10.3389/feart.2022.858814 fatcat:nxrfh5phojhnhfdntb4aatdlpm

An outbreak of tuberculosis in a middle school in Henan, China: Epidemiology and risk factors

Jiying Xu, Guojie Wang, Yanqiu Zhang, Guolong Zhang, Jin Xing, Lihong Qi, Yan Zhuang, Hejun Zeng, Jianhua Chang, Lei Gao
2019 PLoS ONE  
(CSV) Writing -review & editing: Jiying Xu, Guojie Wang, Yanqiu Zhang, Lihong Qi. Fig 1 . 1 Timelines of TB screening and of cases diagnosed. a The four TB screenings.  ... 
doi:10.1371/journal.pone.0225042 pmid:31730664 pmcid:PMC6857903 fatcat:ltkazhmnhffb5fyya27jxe5fya
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