292 results on '"Baoyuan Liu"'
Search Results
2. A nanobody-based blocking enzyme-linked immunosorbent assay for detecting antibodies against pseudorabies virus glycoprotein E
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Huanhuan Lü, Pinpin Ji, Siyu Liu, Ziwei Zhang, Lei Wang, Yani Sun, Baoyuan Liu, Lizhen Wang, and Qin Zhao
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nanobody ,nanobody-HRP ,blocking ELISA ,PRV-gE ,antibody ,Agriculture (General) ,S1-972 - Abstract
Pseudorabies (PR) is an acute infectious disease of pigs caused by the PR virus (PRV) and results in great economic losses to the pig industry worldwide. PRV glycoprotein E (gE)-based enzyme-linked immunosorbent assay (ELISA) has been used to distinguish gE-deleted vaccine-immunized pigs from wild-type virus-infected pigs to eradicate PR in some countries. Nanobody has the advantages of small size and easy genetic engineering and has been a promising diagnostic reagent. However, there were few reports about developing nanobody-based ELISA for detecting anti- PRV-gE antibodies. In the present study, the recombinant PRV-gE was expressed with a bacterial system and used to immunize the Bactrian camel. Then, two nanobodies against PRV-gE were screened from the immunized camel by phage display technique. Subsequently, two nanobody-HRP fusion proteins were expressed with HEK293T cells. The PRV-gE-Nb36-HRP fusion protein was selected as the probe for developing the blocking ELISA (bELISA) to detect anti-PRV-gE antibodies. Through optimizing the conditions of bELISA, the amount of coated antigen was 200 ng per well, and dilutions of the fusion protein and tested pig sera were separately 1:320 and 1:5. The cut-off value of bELISA was 24.20%, and the sensitivity and specificity were 96.43 and 92.63%, respectively. By detecting 233 clinical pig sera with the developed bELISA and a commercial kit, the results showed that the coincidence rate of two assays was 93.99%. Additionallly, epitope mapping showed that PRV-gE-Nb36 recognized a conserved conformational epitope in different reference PRV strains. Simple, great stability and low-cost nanobody-based bELISA for detecting anti-PRV-gE antibodies were developed. The bELISA could be used for monitoring and eradicating PR.
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- 2024
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3. Two nanobody-based immunoassays to differentiate antibodies against genotype 1 and 2 porcine reproductive and respiratory syndrome virus
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Xu Chen, Yueting Chang, Lu Zhang, Xinyu Zhao, Zhihan Li, Zhijie Zhang, Pinpin Ji, Qingyuan Liu, Jiakai Zhao, Jiahong Zhu, Baoyuan Liu, Xinjie Wang, Yani Sun, and Qin Zhao
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PRRSV ,Competitive ELISA ,Nanobody ,Antigen epitope ,Veterinary medicine ,SF600-1100 ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Porcine reproductive and respiratory syndrome virus (PRRSV) infection causes significant economic loss to the global pig industry. Genotype 1 and 2 PRRSV (PRRSV-1 and -2) infections have been reported in China, Europe and America. For accurate prevention, nanobodies were first used as diagnostic reagents for PRRSV typing. In this study three nanobodies targeting both PRRSV-1 and -2, two targeting PRRSV-1 and three targeting PRRSV-2, were screened and produced. To develop two competitive ELISAs (cELISAs), the g1-2-PRRSV-Nb3-HRP nanobody was chosen for the g1-2-cELISA, to detect common antibodies against PRRSV-1 and -2, and the g1-PRRSV-Nb136-HRP nanobody was chosen for the g1-cELISA, to detect anti-PRRSV-1 antibodies. The two cELISAs were developed using PRRSV-1-N protein as coating antigen, and the amounts for both were 100 ng/well. The optimized dilution of testing pig sera was 1:20, the optimized reaction times were 30 min, and the colorimetric reaction times were 15 min. Then, the cut-off values of the g1-2-cELISA and g1-cELISA were 26.6% and 35.6%, respectively. Both of them have high sensitivity, strong specificity, good repeatability, and stability. In addition, for the 1534 clinical pig sera, an agreement rate of 99.02% (Kappa values = 0.97) was determined between the g1-2-cELISA and the commercial IDEXX ELISA kit. For the g1-cELSIA, it can specifically detect anti-PRRSV-1 antibodies in the clinical pig sera. Importantly, combining two nanobody-based cELISAs can differentially detect antibodies against PRRSV-1 and -2. Graphical abstract
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- 2024
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4. Evaluation of novel synthetic peptides of avian hepatitis E virus ORF2 as vaccine candidate in chickens
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Yiyang Chen, Yujia Tang, Shiyu Zhang, Yinuo Tian, Shenhao Xu, Chengwei Zhang, Huanqing Lin, Qin Zhao, En-Min Zhou, and Baoyuan Liu
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Avian hepatitis E virus ,Peptide ,Protection ,Vaccine ,Microbiology ,QR1-502 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Avian hepatitis E virus (HEV) has resulted in significant economic losses in the poultry industry. There is currently no commercial vaccination available to prevent avian HEV infection. Previously, a novel epitope (601TFPS604) was discovered in the ORF2 protein of avian HEV. In this study, peptides were synthesized and assessed for their ability to provide immunoprotecting against avian HEV infection in poultry. Twenty-five Hy-Line Variety Brown laying hens were randomly divided into five groups; groups 1 to 3 respectively immunized with RLLDRLSRTFPS, PETRRLLDRLSR (irrelevant peptide control), or truncated avian HEV ORF2 protein (aa 339–606), while group 4 (negative control) was mock-immunized with PBS and group 5 (normal control) was not immunized or challenged. After the challenge, all hens in groups 2 and 4 showed seroconversion, fecal virus shedding, viremia, alanine aminotransferase (ALT) level increasing, liver lesions and HEV antigen in the liver. There were no pathogenic effects in other groups. Collectively, all of these findings showed that hens were completely protected against avian HEV infection when they were immunized with the peptide containing TFPS of the avian HEV ORF2 protein.
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- 2024
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5. A new high-resolution global topographic factor dataset calculated based on SRTM
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Yuwei Sun, Hongming Zhang, Qinke Yang, Rui Li, Baoyuan Liu, Xining Zhao, Haijing Shi, Hongyi Li, Yuhan Ren, Xiao Fan, Liang Dong, Yikun Xu, Yi Chang, and Linlin Yuan
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Science - Abstract
Abstract Topography is an important factor affecting soil erosion and is measured as a combination of the slope length and slope steepness (LS-factor) in erosion models, like the Chinese Soil Loss Equation. However, global high-resolution LS-factor datasets have rarely been published. Challenges arise when attempting to extract the LS-factor on a global scale. Furthermore, existing LS-factor estimation methods necessitate projecting data from a spherical trapezoidal grid to a planar rectangle, resulting in grid size errors and high time complexity. Here, we present a global 1-arcsec resolution LS-factor dataset (DS-LS-GS1) with an improved method for estimating the LS-factor without projection conversion (LS-WPC), and we integrate it into a software tool (LS-TOOL). Validation of the Himmelblau–Orlandini mathematical surface shows that errors are less than 1%. We assess the LS-WPC method on 20 regions encompassing 5 landform types, and R2 of LS-factor are 0.82, 0.82, 0.83, 0.83, and 0.84. Moreover, the computational efficiency can be enhanced by up to 25.52%. DS-LS-GS1 can be used as high-quality input data for global soil erosion assessment.
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- 2024
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6. Comparison and quantitative assessment of two regional soil erosion survey approaches
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Lixia Dong, Suhua Fu, Baoyuan Liu, and Bing Yin
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Regional soil erosion ,Soil erosion survey ,Grid approach ,Sampling approach ,CSLE ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Regional soil erosion surveys are the first step of soil conservation planning. Grid and sampling approaches are commonly used for soil erosion surveys at the regional scale. With the grid approach, the region is divided into grids (e.g., 1 km × 1 km), and the soil erosion rate of each grid was calculated. With the sampling approach, a small portion of the area (typically 4% or less) was taken and then the soil erosion rate was calculated. Based on the above calculation, both approaches evaluated the soil erosion area (which is the area where the soil erosion rate is greater than the soil loss tolerance (t)) and its distribution in the whole region. The purpose of this paper is to compare the assessment results of the two approaches and analyse their practicality using Yunyang County, Chongqing, China (area is 3636 km2). The soil erosion rate, percentage of soil erosion area (PSEA, which is the ratio of the area where the soil erosion rate is greater than the soil loss tolerance (t) to the area of the total study region) and its spatial distribution were compared between the two approaches. The results showed that the grid approach overestimated the average soil erosion rate and PSEA overall for all 33 sample units and the whole region in comparison to the sampling approach. The sampling approach can yield a reasonable spatial distribution of the soil erosion rate in the whole region. In addition, the soil erosion regions were more clustered than those using the grid approach, which can be more suitable for soil conservation planning. Therefore, the sampling approach is an efficient and practical approach in regional soil erosion surveys. The results can provide insights into regional soil erosion surveys.
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- 2023
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7. Hepatitis E virus causes apoptosis of ovarian cells in hens and resulting in a decrease in egg production
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Yuan Zhang, Xueyan Gao, Mengdan Cao, Huanyu Xu, Hanyi Liu, Qin Zhao, En-Min Zhou, Yiyang Chen, and Baoyuan Liu
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hepatitis E virus ,pathogenicity ,ovary ,apoptosis ,Animal culture ,SF1-1100 - Abstract
ABSTRACT: Previous studies have shown that avian hepatitis E virus (HEV) decreases egg production by 10-40% in laying hens, but have not fully elucidated the mechanism of there. In this study, we evaluated the replication of avian HEV in the ovaries of laying hens and the mechanism underlying the decrease in egg production. Forty 150-days-old commercial laying hens were randomly divided into 2 groups of 20 hens each. A total of 1 mL (104GE) of avian HEV stock was inoculated intravenously into each chicken in the experimental group, with 20 chickens in the other group serving as negative controls. Five chickens from each group were necropsied weekly for histopathological examination. The pathogenicity of avian HEV has been characterized by seroconversion, viremia, fecal virus shedding, ovarian lesions, and decreased egg production. Both positive and negative-strand avian HEV RNA, and ORF2 antigens can be detected in the ovaries, suggesting that avian HEV can replicate in the ovaries and serve as an important extrahepatic replication site. The ovaries of laying hens underwent apoptosis after avian HEV infection. These results indicate that avian HEV infection and replication in ovarian tissues cause structural damage to the cells, leading to decreased egg production.
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- 2024
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8. Response of soil erosion to vegetation and terrace changes in a small watershed on the Loess Plateau over the past 85 years
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Tianle Ma, Baoyuan Liu, Liang He, Lixia Dong, Bing Yin, and Yunge Zhao
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CSLE model ,Soil erosion ,Vegetation change ,Terrace ,Loess Plateau ,Science - Abstract
Land use on the Chinese Loess Plateau has undergone dramatic changes over the past few decades. The implementation of a series of soil and water conservation measures has significantly altered the soil erosion, transportation, and deposition processes on the Loess Plateau. To effectively address and mitigate soil erosion, it is crucial to accurately quantify the soil loss rate and analyze the contributions of soil and water conservation measures over the past several decades. In this study, the Zhifanggou watershed, located in the hilly area of the Chinese Loess Plateau, is utilized as an illustrative example. Using historical data, remote sensing imagery, and on-site data of soil, vegetation, and soil conservation measures, we assessed the soil loss rates from 1938 to 2022 based on long-term land use changes, utilizing the Chinese Soil Loss Equation (CSLE) model. Furthermore, we employed a quantitative evaluation to assess the impacts of vegetation change and terrace construction on soil erosion. The findings of our study reveal significant transformations in land use. Farmland experienced an initial increase followed by a subsequent decline, while the opposite pattern was observed for forest land. The simulated soil loss rate for the entire watershed exhibited an upward trend, rising from 34.86 t·ha−1·yr−1 in 1938 to 104.11 t·ha−1·yr−1 in 1958, before declining to 56.98 t·ha−1·yr−1 in 1999 and reaching 5.87 t·ha−1·yr−1 in 2022. Attribution analysis showed that vegetation change exerted a dominant influence on recent soil erosion dynamics, accounting for 86.10 % of the total contribution in 2022, while terraces contributed 13.90 %. These findings clarify long-term soil erosion mechanisms and provide guidance for watershed soil and water conservation management.
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- 2024
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9. Vegetation characteristics and soil properties in grazing exclusion areas of the Inner Mongolia desert steppe
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Wenbang Gao, Hongtao Jiang, Shuai Zhang, Chunxing Hai, and Baoyuan Liu
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Fencing time ,Soil restoration ,Vegetation ,Inner Mongolian desert steppe ,Grazing ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In arid and semi-arid desert steppe areas, grazing exclusion with fencing is widely regarded as an effective strategy for restoring degraded vegetation and enhancing the quality of degraded soil. In this study, we hypothesized that grazing exclusion caused by fencing enhances both vegetation and soil properties, and that the longer an area is fenced, the more considerable the improvement. We conducted an observational study wherein random sampling was utilized to select 9 plots fenced for ten or more years, 25 plots fenced for four to nine years, 25 plots fenced for one to three years and 29 free-grazing plots within an area of approximately 63,000 km2 of Inner Mongolia desert steppe. A one-way ANOVA revealed no significant differences in the characteristics of grassland vegetation or soil properties between grasslands fenced for one to three years and free-grazing grassland. After 4 years of fencing, noticeable increases in above-ground biomass, litter content, Simpson index, soil organic carbon, and available nitrogen were observed. Significant positive differences in vegetation coverage, height, species richness, soil available phosphorus, and available potassium were associated with plots with a minimum of 10 years of fencing. The soil layer with the greatest difference in the fenced-in areas for soil organic carbon was at 0–25 cm. For available nitrogen and available phosphorus, fencing produced the most significant differences in the 0–20 cm soil layer, while for available potassium, fencing produced the most significant differences in the 0–30 cm soil layer. However, the fencing did not indicate any statistically significant differences in terms of clay, silt, and sand content in any soil layer. The data support our hypothesis that grazing exclusion improves both vegetation and soil properties, and that longer periods of grazing exclusion result in greater degrees of improvement. This research offers technical guidance for the reasonable choice of fencing time across a vast area of the Inner Mongolian desert steppe.
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- 2023
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10. Call for joint international actions to improve scientific understanding and address soil erosion and riverine sediment issues in mountainous regions
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Fan Zhang, Baoyuan Liu, Liping Zhu, Richard Cruse, Dongfeng Li, Panos Panagos, Pasquale Borrelli, Yakov Kuzyakov, and Shaoshan An
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Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
During the International Workshop on Soil Erosion and Riverine Sediment in Mountainous Regions held in November 2022, scientists from many countries shared their state-of-the-art knowledge and brainstormed to improve scientific understanding for coping with climate change and anthropogenic impacts. Information summarized in this discussion includes proposed key scientific questions and suggested joint actions to reduce soil erosion and riverine sediment problems in mountainous regions.
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- 2023
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11. Improvement of water yield and net primary productivity ecosystem services in the Loess Plateau of China since the 'Grain for Green' project
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Wanyun Huang, Peng Wang, Liang He, and Baoyuan Liu
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The Loess Plateau ,Water yield ,Net primary productivity ,Ecosystem service ,Teleconnection factor ,Cross-wavelet analysis ,Ecology ,QH540-549.5 - Abstract
The Loess Plateau of China is one of the regions with the most serious soil erosion globally. The ambitious “Grain for Green” project was there implemented to restore degraded ecosystems, profoundly changing the water yield and carbon sequestration ecosystem services. To understand the changes of water- and carbon-related ecosystem services (hereafter WCES) in the Loess Plateau, this study combined the CASA (Carnegie-Ames-Stanford Approach) model and InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) model to thoroughly reveal the changes and intrinsic linkages of water yield and net primary productivity since the “Grain for Green” project in the Loess Plateau. The results show that the WCES of the Loess Plateau were increasing since 2001, dominated by both the climate change and human afforestation. The water yield and net primary productivity showed strong synergistic effects in 80% of the Loess Plateau, mainly resulting from the rapid increase of precipitation in recent years. The increasing atmospheric precipitation contributed to more WCES provisions, which may have offset the trade-off between WCES caused by large-scale afforestation. In view of the synergistic effects of WCES, enhancing water input into the ecosystem may be an effective measure to respond with future WCES degradation in dry years, such as artificial basin-cross water transfer project. Despite the low correlation between teleconnection factors and WCES, the low water yield and reduction of net primary productivity may be associated with a strong El Niño event in 2015. This study assists in a wise decision-making on the future “Grain for Green” and ecological management in the Loess Plateau.
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- 2023
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12. Development and Application of a Nanobody-Based Competitive ELISA for Detecting Antibodies against Hepatitis E Virus from Humans and Domestic Animals
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Yiyang Chen, Meimei Zhang, Tianxiang Chen, Jiaxi Wang, Qin Zhao, En-Min Zhou, and Baoyuan Liu
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hepatitis E virus (HEV) ,cELISA ,antibodies ,humans ,domestic animals ,Microbiology ,QR1-502 - Abstract
ABSTRACT Hepatitis E virus (HEV) is a zoonotic pathogen that is widespread worldwide. At present, most enzyme-linked immunosorbent assay (ELISA) kits only detect antibodies against human HEV. In this study, a nanobody-horseradish peroxidase (HRP) fusion protein-based competitive ELISA (cELISA) with more convenience and spectral characteristics for HEV antibody detection was developed and used to detect HEV IgG in various species. First, 6 anti-swine HEV capsid protein nanobodies were screened using phage display technology from an immunized Bactrian camel. Then, HEV-Nb67-HRP fusions were expressed and used as a probe for developing a cELISA. The cutoff value of the cELISA was 17.8%, and there was no cross-reaction with other anti-swine virus antibodies, suggesting that the cELISA had good specificity. The intra-assay and interassay coefficients of variation (CVs) were 1.33 to 5.06% and 1.52 to 6.84%, respectively. The cELISA and Western blot showed a higher coincidence rate (97.14%, kappa value = 0.927) than cELISA and indirect ELISA (95.00%, kappa value = 0.876) in clinical swine serum samples. Finally, the seroprevalence of HEV IgG in humans, pigs, rabbits, cows, and goats was 30.67%, 19.26%, 8.75%, 27.59%, and 18.08%, respectively, suggesting that cELISA may have a broader scale for mammalian HEV antibody detection. These results suggest that the newly developed cELISA was rapid, low-cost, reliable, and useful for the serological evaluation of current HEV. IMPORTANCE HEV is thought to be a zoonotic infection and is widespread worldwide; it is beneficial to establish a more convenient and spectral method for HEV antibody detection. In this study, a convenient, time-saving, reproducible, highly sensitive, specific, and novel nanobody-based cELISA was developed and can be used to detect IgG antibodies against mammalian HEV. It provides a new technique for serological evaluation and ELISA-based diagnosis of HEV infection.
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- 2023
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13. Quantifying spatial distribution of interrill and rill erosion in a loess at different slopes using structure from motion (SfM) photogrammetry
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Tao He, Yang Yang, Yangzi Shi, Xiaozhen Liang, Suhua Fu, Gege Xie, Baoyuan Liu, and Yingna Liu
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Interrill and rill erosion ,Spatial distribution ,Structure from motion (SfM) photogrammetry ,Slope ,Rainfall simulation ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The spatial distribution of interrill and rill erosion is essential for unravelling soil erosion principles and the application of soil and water conservation practices. To quantify interrill and rill erosion and their spatial development, four 30-min rainfalls at 90 mm h−1 intensity were consecutively simulated on runoff plots packed with a loess at six slopes of 10°, 15°, 20°, 25°, 30° and 35°. The soil surface was measured using the structure from motion (SfM) photogrammetry upon each simulation run, and the runoff and sediment samples were collected and measured at every 10 min. Rills did not develop until the third simulation run. During the initial two runs, the lower third section was more severely eroded than the upper and middle thirds along the slope direction, yet the interrill erosion was statistically uniform from left to right. Rills tended to emerge by both sidewalls and in the lower portion in the third run. The corresponding rill erosion increased with slope from 10° to 20° and then decreased for the slopes steeper, which was consistent with the slope trend of the sediment yield directly measured. The rills expanded substantially primarily via head retreat and to a lesser extent via sideward erosion after receiving another 30-min rainfall. Rill erosion contributed 69.3% of the total erosion loss, and shifted the critical slope corresponding to the maximum loss from 20° to 25°. These findings demonstrate the significance of rill erosion not only in total soil loss but also in its relation to slope, as well as the effectiveness of SfM photogrammetry in quantifying interrill and rill erosion.
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- 2022
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14. Rainfall Erosivity Mapping for Tibetan Plateau Using High-Resolution Temporal and Spatial Precipitation Datasets for the Third Pole
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Bing Yin, Yun Xie, Bing Liu, and Baoyuan Liu
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Tibetan Plateau ,rainfall erosivity ,high-resolution precipitation dataset ,spatial distribution ,Science - Abstract
Low-density weather station and high topographic variance limited rainfall erosivity (RE) calculation for Tibetan Plateau (TP). The accuracy of RE prediction from three data sources (a High-resolution Precipitation dataset for the Third Pole (TPHiPr), IMERG Final Run (IMERG-F) and weather station daily precipitation data) were evaluated for the TP, and the variations were analyzed from 2001 to 2020. The results showed that TPHiPr can more accurately characterize spatial and temporal variations of the RE on the TP. TPHiPr can better represent the impact of topography on precipitation, effectively compensating the deficiencies in precipitation data from low-density stations. The R2 and NSE between the mean annual/monthly RE of TPHiPr and the station data were around 0.9. TPHiPr effectively revealed rain shadow areas on the northern slopes of the Himalayas and calculated RE more accurately in the broad-leaved evergreen forest zone on the southern flank of the Himalayas and the arid regions to the northwest. RE from 2001 to 2020 showed an overall increasing trend. However, TPHiPr produced underestimates in the southern valleys and the eastern Hengduan Mountains, while overestimates in the southeastern area at lower elevations. This research provided a new and more accurate RE data for the TP.
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- 2023
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15. Identification and pathogenicity of hepatitis E Virus from laboratory Bama miniature pigs
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Baoyuan Liu, Yiyang Chen, Meimei Zhang, Tianxiang Chen, Yuan Zhang, DanBaZhaXi, Shixuan Xu, Qin Zhao, and En-Min Zhou
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Hepatitis E virus ,Bama miniature pig ,Sequence analysis ,Pathogenicity ,Veterinary medicine ,SF600-1100 - Abstract
Abstract Background Hepatitis E virus (HEV) genotypes 3 and 4 are zoonotic. In this study, HEV infection in laboratory Bama miniature pigs in Sichuan Province of China was investigated. Firstly, one hundred rectal swabs were collected for HEV RNA testing, and chose positive samples for sequence analysis. Concurrently, for pathogenicity study, six healthy Bama miniature pigs were randomly divided into two groups of 3 pigs each. A total of 500 μL of HEV stock (positive fecal samples identified in this study) was inoculated intravenously into each pig in the experimental group, and the three pigs in the other group served as negative controls. Serum and fecal samples were collected at 1 to 10 weeks post-inoculation (wpi) for alanine aminotransferase (ALT) levels, anti-HEV antibodies and HEV RNA detection, respectively. During necropsies, liver lesions and HEV antigen in liver were observed at 10 wpi. Results The rate of fecal sample HEV RNA-positivity was 12% (12/100). Sequence comparisons indicated that partial ORF1 and ORF2 gene sequences of this isolate shared highest identities with corresponding sequences of genotype 4a HEV isolates (81.4%-96.1% and 89.9%-97.1%, respectively). Phylogenetic tree analysis further demonstrated that sequences of this isolate clustered together with sub-genotype 4a HEV isolate sequences. Experimentally, the pathogenicity of Bama miniature pigs infected with this isolate exhibited viremia, fecal virus shedding, seroconversion, ALT level increasing, liver lesions and HEV antigen in liver. Conclusions This is the first study to confirm that HEV is currently circulating in laboratory Bama miniature pigs in China and this isolate can successfully infect Bama miniature pigs experimentally. More importantly, this study suggested HEV screening of laboratory pigs should be conducted to prevent research personnel from acquiring zoonotic HEV infections.
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- 2022
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16. Development of a novel competitive ELISA based on nanobody-horseradish peroxidase fusion protein for rapid detection of antibodies against avian hepatitis E virus
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Tianxiang Chen, Baoyuan Liu, Yiyang Chen, Xueting Wang, Meimei Zhang, Xukun Dang, Qin Zhao, and En-Min Zhou
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nanobody-HRP fusion protein ,HEK293T ,competitive ELISA ,avian HEV ,antibody detection ,Animal culture ,SF1-1100 - Abstract
ABSTRACT: Avian hepatitis E virus (avian HEV) increases poultry mortality and decreases egg production, leading to huge economic losses worldwide. However, there is no effective serological test for avian HEV. Researchers previously created a testing platform using the nanobody (Nb)-horseradish peroxidase (HRP) fusion protein as an ultrasensitive probe to develop competitive ELISA (cELISA) to detect antibodies against different animal viruses. In this study, a rapid and reliable cELISA was developed to test for antibodies against avian HEV using the same platform. Six anti-avian HEV capsid protein nanobodies were selected from an immunized Bactrian camel using phage display technology. The avian HEV-Nb49-HRP fusion protein was expressed and used as a probe for developing a cELISA assay to test for avian HEV antibodies. The cut-off value of the developed cELISA was 22.0%. There was no cross-reaction with other anti-avian virus antibodies, suggesting that the cELISA had good specificity. The coefficients of variation were 0.91% to 4.21% (intra-assay) and 1.52% to 6.35% (inter-assay). Both cELISA and indirect ELISA showed a consistency of 86.7% (kappa = 0.738) for clinical chicken serum samples, and coincidence between cELISA and Western blot was 96.0% (kappa = 0.919). The epitope recognized by Nb49 was located in aa 593-604 of the avian HEV capsid protein, and the peptide (TFPS) in aa 601-604 was essential for binding. The novel cELISA is a saving cost, rapid, useful, and reliable assay for the serological investigation of avian HEV. More importantly, the peptide TFPS may be crucial to immunodominant antigen composition and protection.
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- 2023
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17. Identification of two novel neutralizing nanobodies against swine hepatitis E virus
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Yiyang Chen, Xueting Wang, Meimei Zhang, Jinyao Li, Xueyan Gao, Yuchen Nan, Qin Zhao, En-Min Zhou, and Baoyuan Liu
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hepatitis E virus ,zoonotic ,nanobodies ,neutralizing ,antiviral ,Microbiology ,QR1-502 - Abstract
Hepatitis E virus (HEV) is thought to be a zoonotic pathogen that causes serious economic loss and threatens human health. However, there is a lack of efficient antiviral strategies. As a more promising tool for antiviral therapy, nanobodies (also named single-domain antibodies, sdAbs) exhibit higher specificity and affinity than traditional antibodies. In this study, nanobody anti-genotype four HEV open reading frame 2 (ORF2) was screened using phage display technology, and two nanobodies (nb14 and nb53) with high affinity were prokaryotically expressed. They were identified to block HEV ORF2 virus like particle (VLP) sp239 (aa 368–606) absorbing HepG2 cells in vitro. With the previously built animal model, the detection indicators of fecal shedding, viremia, seroconversion, alanine aminotransferase (ALT) levels, and liver lesions showed that nb14 could completely protect rabbits from swine HEV infection, and nb53 partially blocked swine HEV infection in rabbits. Collectively, these results revealed that nb14, with its anti-HEV neutralizing activity, may be developed as an antiviral drug for HEV.
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- 2022
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18. Assessing soil thickness in a black soil watershed in northeast China using random forest and field observations
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Shuai Zhang, Gang Liu, Shuli Chen, Craig Rasmussen, and Baoyuan Liu
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Soil thickness ,Random forest ,Black soils ,Northeast China ,Soil geomorphology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Soil thickness determines the soil productivity in the black soil region of northeast China, which is important for national food security. Existing information on the spatial variation of black soil thickness is inadequate. In this paper, we propose a model framework for spatial estimation of the black soil thickness at the watershed scale by integrating field observations, unmanned aerial vehicle variations of topography, and satellite variations of vegetation with the aid of random forest. We sampled 141 sample profiles over a watershed and identified the black soil thickness based on indices of the mollic epipedon. Topographic variables were derived from a digital elevation model and vegetation variables were derived from Landsat 8 imagery. Random forest was used to determine the relationship between black soil thickness and environmental variables. The resulting model explained 61% of the black soil thickness spatial variation, which was more than twice that of traditional interpolation methods (ordinary kriging, universal kriging and inverse distance weighting). Topographic variables contributed the most toward explaining the thickness, followed by vegetation indices. The black soil thickness over the watershed had a clear catenary soil pattern, with thickest black soil in the low depositional areas and thinnest at the higher elevations that drain into the low areas. The proposed model framework will improve estimates of soil thickness in the region of our study.
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- 2021
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19. A nanobody‐horseradish peroxidase fusion protein‐based competitive ELISA for rapid detection of antibodies against porcine circovirus type 2
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Yang Mu, Cunyu Jia, Xu Zheng, Haipeng Zhu, Xin Zhang, Haoran Xu, Baoyuan Liu, Qin Zhao, and En-Min Zhou
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Nanobody-HRP fusion protein ,Competitive ELISA ,PCV2 ,Antibody detection ,Biotechnology ,TP248.13-248.65 ,Medical technology ,R855-855.5 - Abstract
Abstract Background The widespread popularity of porcine circovirus type 2(PCV2) has seriously affected the healthy development of the pig industry and caused huge economic losses worldwide. A rapid and reliable method is required for epidemiological investigation and evaluating the effect of immunization. However, the current methods for PCV2 antibody detection are time-consuming or very expensive and rarely meet the requirements for clinical application. we have constructed the platform for expressing the nanobody(Nb)‑horseradish peroxidase(HRP) fusion protein as an ultrasensitive probe to detect antibodies against the Newcastle disease virus(NDV), previously. In the present work, an Nb-HRP fusion protein-based competitive ELISA(cELISA) for rapid and simple detection antibodies against PCV2 was developed using this platform to detect anti-PCV2 antibodies in clinical porcine serum. Results Using phage display technology, 19 anti-PCV2-Cap protein nanobodies were screened from a PCV2-Cap protein immunized Bactrian camel. With the platform, the PCV2-Nb15‑HRP fusion protein was then produced and used as a sensitive reagent for developing a cELISA to detect anti‑PCV2 antibodies. The cut‑off value of the cELISA is 20.72 %. Three hundreds and sixty porcine serum samples were tested by both newly developed cELISA and commercial kits. The sensitivity and specificity were 99.68 % and 95.92 %, respectively. The coincidence rate of the two methods was 99.17 %. When detecting 620 clinical porcine serum samples, a good consistent (kappa value = 0.954) was found between the results of the cELISA and those of commercial kits. Conclusions In brief, the newly developed cELISA based PCV2-Nb15‑HRP fusion protein is a rapid, low-cost, reliable and useful nanobody-based tool for the serological evaluation of current PCV2 vaccine efficacy and the indirect diagnosis of PCV2 infection.
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- 2021
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20. The assessment of soil loss by water erosion in China
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Baoyuan Liu, Yun Xie, Zhiguang Li, Yin Liang, Wenbo Zhang, Suhua Fu, Shuiqing Yin, Xin Wei, Keli Zhang, Zhiqiang Wang, Yingna Liu, Ying Zhao, and Qiankun Guo
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National soil erosion survey ,CSLE ,Sample units ,Chinese soil loss map ,Soil erosion rate ,Ratio of soil erosion area ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Soil erosion is a major environmental problem in China. Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information. The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011. A multi-stage, unequal probability, systematic area sampling method was employed. A total of 32,948 sample units, which were either 0.2–3 km2 small catchments or 1 km2 grids, were investigated on site. Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit, along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units. Maps were created by using a spatial interpolation method at national, river basin, and provincial scales. Results showed that the calculated average soil erosion rate was 5 t ha−1 yr−1 in China, and was 18.2 t ha−1 yr−1 for sloped, cultivated cropland. Intensive soil erosion occurred on cropland, overgrazing grassland, and sparsely forested land. The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids. The national average ratio was 13.5%, which represents the area of land in China that requires the implementation of soil conservation practices. These survey results and the maps provide the basic information for national conservation planning and policymaking.
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- 2020
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21. Impacts of horizontal resolution and downscaling on the USLE LS factor for different terrains
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Chunmei Wang, Linxin Shan, Xin Liu, Qinke Yang, Richard M. Cruse, Baoyuan Liu, Rui Li, Hongming Zhang, and Guowei Pang
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LS factor ,SRTM ,Resolution ,Downscale ,USLE ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Slope length and slope steepness are critical topographic factors (L and S) in the Universal Soil Loss Equation (USLE) and Chinese Soil Loss Equation (CSLE) for soil erosion modelling. Both slope length and slope gradient are potentially sensitive to spatial resolution when calculated in a GIS framework. The resolution effect on the LS factor and approaches suitable for improving the LS factor at a coarse resolution have not been well identified. To address this problem, the LS factor at 5-m and 30-m resolution in twenty-four watersheds with various terrains was estimated. And a downscale model based on matching of the lower resolution LS cumulative frequency curves to a higher resolution (“Histogram Matching” method) was tested for its potential to improve LS factor estimation accuracy. In the larger relief mountainous area, compared to 5-m resolution, the 30-m resolution generated LS was generally overestimated by more than 20% and in lower relief areas underestimated by more than 15%. This bias is less than 10% in medium relief areas. The downscale model improved LS factor estimates compared to the 30-m resolution estimate by more than 10% when comparing frequency distribution curves and more than 20% in mean values in larger relief areas. The downscale model worked well in all regions except for the low relief areas, which intuitively are the low soil erosion potential areas. The results of this research help quantify the uncertainty in soil erosion estimates and may ultimately help to improve the assessment of soil erosion through its impact on LS factor estimates, especially at regional and global scales.
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- 2020
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22. Study on a soil erosion sampling survey in the Pan-Third Pole region based on higher-resolution images
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Qinke Yang, Mengyang Zhu, Chunmei Wang, Xiaoping Zhang, Baoyuan Liu, Xin Wei, Guowei Pang, Chaozhen Du, and Lihua Yang
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Pan -third pole area ,Land use ,Soil conservation measures ,Remote sensing ,Variable probability sampling ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Soil erosion is one of the most severe global environmental problems, and soil erosion surveys are the scientific basis for planning soil conservation and ecological development. To improve soil erosion sampling survey methods and accurately and rapidly estimate the actual rates of soil erosion, a Pan-Third Pole region was taken as an example to study a methodology of soil erosion sampling survey based on high-spatial-resolution remote sensing images. The sampling units were designed using a stratified variable probability systematic sampling method. The spatiotemporal characteristics of soil erosion and conservation were taken into account, and finer-resolution freely available and accessible images in Google Earth were used. Through the visual interpretation of the free high-resolution remote sensing images, detailed information on land use and soil conservation measures was obtained. Then, combined with the regional soil erosion factor data products, such as rainfall-runoff erosivity factor (R), soil erodibility factor (K), and slope length and steepness factor (LS), the soil loss rates of some sampling units were calculated. The results show that, based on these high-resolution remote sensing images, the land use and soil conservation measures of the sampling units can be quickly and accurately extracted. The interpretation accuracy in 4 typical cross sections was more than 80%, and sampling accuracy, described by histogram similarity in 11 large sampling sites, show that the landuse of sampling uints can represent the structural characteristics of regional land use. Based on the interpretation of data from the sample survey and the regional soil erosion factor data products, the calculation of the soil erosion rate can be completed quickly. The calculation results can reflect the actual conditions of soil erosion better than the potential soil erosion rates calculated by using the coarse-resolution remote sensing method.
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- 2020
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23. Avian Hepatitis E Virus ORF2 Protein Interacts with Rap1b to Induce Cytoskeleton Rearrangement That Facilitates Virus Internalization
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Beibei Zhang, Mengnan Fan, Jie Fan, Yuhang Luo, Jie Wang, Yajing Wang, Baoyuan Liu, Yani Sun, Qin Zhao, Julian A. Hiscox, Yuchen Nan, and En-Min Zhou
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hepatitis E virus ,Rap1b ,virion internalization ,cytoskeleton rearrangement ,viral capsids ,Microbiology ,QR1-502 - Abstract
ABSTRACT Avian hepatitis E virus (HEV) causes liver diseases and multiple extrahepatic disorders in chickens. However, the mechanisms involved in avian HEV entry remain elusive. Herein, we identified the RAS-related protein 1b (Rap1b) as a potential HEV-ORF2 protein interacting candidate. Experimental infection of chickens and cells with an avian HEV isolate from China (CaHEV) led to upregulated expression and activation of Rap1b both in vivo and in vitro. By using CaHEV capsid as mimic of virion to treat cell in vitro, it appears that the interaction between the viral capsid and Rap1b promoted cell membrane recruitment of the downstream effector Rap1-interacting molecule (RIAM). In turn, RIAM further enhanced Talin-1 membrane recruitment and retention, which led to the activation of integrin α5/β1, as well as integrin-associated membrane protein kinases, including focal adhesion kinase (FAK). Meanwhile, FAK activation triggered activation of downstream signaling molecules, such as Ras-related C3 botulinum toxin substrate 1 RAC1 cell division cycle 42 (CDC42), p21-activated kinase 1 (PAK1), and LIM domain kinase 1 (LIMK1). Finally, F-actin rearrangement induced by Cofilin led to the formation of lamellipodia, filopodia, and stress fibers, contributes to plasma membrane remodeling, and might enhance CaHEV virion internalization. In conclusion, our data suggested that Rap1b activation was triggered during CaHEV infection and appeared to require interaction between CaHEV-ORF2 and Rap1b, thereby further inducing membrane recruitment of Talin-1. Membrane-bound Talin-1 then activates key Integrin-FAK-Cofilin cascades involved in modulation of actin kinetics, and finally leads to F-actin rearrangement and membrane remodeling to potentially facilitate internalization of CaHEV virions into permissive cells. IMPORTANCE Rap1b is a multifunctional protein that is responsible for cell adhesion, growth, and differentiation. The inactive form of Rap1b is phosphorylated and distributed in the cytoplasm, while active Rap1b is prenylated and loaded with GTP to the cell membrane. In this study, the activation of Rap1b was induced during the early stage of avian HEV infection under the regulation of PKA and SmgGDS. Continuously activated Rap1b recruited its effector RIAM to the membrane, thereby inducing the membrane recruitment of Talin-1 that led to the activation of membrane α5/β1 integrins. The triggering of the signaling pathway-associated Integrin α5/β1-FAK-CDC42&RAC1-PAK1-LIMK1-Cofilin culminated in F-actin polymerization and membrane remodeling that might promote avian HEV virion internalization. These findings suggested a novel mechanism that is potentially utilized by avian HEV to invade susceptible cells.
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- 2022
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24. Fenobody and RANbody-based sandwich enzyme-linked immunosorbent assay to detect Newcastle disease virus
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Pinpin Ji, Jiahong Zhu, Xiaoxuan Li, Wenqi Fan, Qianqian Liu, Kun Wang, Jiakai Zhao, Yani Sun, Baoyuan Liu, En-Min Zhou, and Qin Zhao
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Fenobody ,Ranbody ,Reporter-nanobody fusions ,Sandwich enzyme-linked immunosorbent assay ,NDV ,Biotechnology ,TP248.13-248.65 ,Medical technology ,R855-855.5 - Abstract
Abstract Background Traditional sandwich enzyme-linked immunosorbent assay (ELISA) using polyclonal and monoclonal antibodies as reagents presents several drawbacks, including limited amounts, difficulty in permanent storage, and required use of a secondary antibody. Nanobodies can be easily expressed with different systems and fused with several tags in their tertiary structure by recombinant technology, thus offering an effective detection method for diagnostic purposes. Recently, the fenobody (ferritin-fused nanobody) and RANbody (nanobody-fused reporter) have been designed and derived from the nanobody for developing the diagnostic immunoassays. However, there was no report about developing the sandwich ELISA using the fenobody and RANbody as pairing reagents. Results A platform for developing a sandwich ELISA utilizing fenobody as the capture antibody and RANbody as the detection antibody was firstly designed in the study. Newcastle disease virus (NDV) was selected as the antigen, from which 13 NDV-specific nanobodies were screened from an immunized Bactrian camel. Then, 5 nanobodies were selected to produce fenobodies and RANbodies. The best pairing of fenobodies (NDV-fenobody-4, 800 ng/well) and RANbodies (NDV-RANbody-49, 1:10) was determined to develop the sandwich ELISA for detecting NDV. The detection limits of the assay were determined to be 22 of hemagglutination (HA) titers and 10 ng of purified NDV particles. Compared with two commercial assays, the developed assay shows higher sensitivity and specificity. Meanwhile, it exhibits 98.7% agreement with the HA test and can detect the reference NDV strains belonging to Class II but not Class I. Conclusions In the presented study, the 13 anti-NDV nanobodies binding the NDV particles were first produced. Then, for the first time, the sandwich ELISA to detect the NDV in the different samples has been developed using the fenobody and RANbody as reagents derived from the nanobodies. Considering the rapidly increasing generation of nanobodies, the platform can reduce the cost of production for the sandwich ELISA and be universally used to develop assays for detecting other antigens.
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- 2020
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25. Nanobody‑horseradish peroxidase and -EGFP fusions as reagents to detect porcine parvovirus in the immunoassays
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Qizhong Lu, Xiaoxuan Li, Jiakai Zhao, Jiahong Zhu, Yuhang Luo, Hong Duan, Pinpin Ji, Kun Wang, Baoyuan Liu, Xueting Wang, Wenqi Fan, Yani Sun, En-Min Zhou, and Qin Zhao
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Nanobody ,Nanobody-HRP ,Nanobody-EGFP ,Porcine parvovirus ,VP2 ,Biotechnology ,TP248.13-248.65 ,Medical technology ,R855-855.5 - Abstract
Abstract Background Antibodies are an important reagent to determine the specificity and accuracy of diagnostic immunoassays for various diseases. However, traditional antibodies have several shortcomings due to their limited abundance, difficulty in permanent storage, and required use of a secondary antibody. Nanobodies, which are derived from single-chain camelid antibodies, can circumvent many of these limitations and, thus, appear to be a promising substitute. In the presented study, a sandwich ELISA-like immunoassay and direct fluorescent assay with high sensitivity, good specificity, and easy operation were the first time to develop for detecting porcine parvovirus (PPV). After screening PPV viral particles 2 (VP2) specific nanobodies, horseradish peroxidase (HRP) and enhanced green fluorescent protein (EGFP) fusions were derived from the nanobodies by recombinant technology. Finally, using the nanobody-HRP and -EGFP fusions as probes, the developed immunoassays demonstrate specific, sensitive, and rapid detection of PPV. Results In the study, five PPV-VP2 specific nanobodies screened from an immunised Bactrian camel were successfully expressed with the bacterial system and purified with a Ni–NTA column. Based on the reporter-nanobody platform, HRP and EGFP fusions were separately produced by transfection of HEK293T cells. A sandwich ELISA-like assay for detecting PPV in the samples was firstly developed using PPV-VP2-Nb19 as the capture antibody and PPV-VP2-Nb56-HRP fusions as the detection antibody. The assay showed 92.1% agreement with real-time PCR and can be universally used to surveil PPV infection in the pig flock. In addition, a direct fluorescent assay using PPV-VP2-Nb12-EGFP fusion as a probe was developed to detect PPV in ST cells. The assay showed 81.5% agreement with real-time PCR and can be used in laboratory tests. Conclusions For the first time, five PPV-VP2 specific nanobody-HRP and -EGFP fusions were produced as reagents for developing immunoassays. A sandwich ELISA-like immunoassay using PPV-VP2-Nb19 as the capture antibody and PPV-VP2-Nb56-HRP fusion as the detection antibody was the first time to develop for detecting PPV in different samples. Results showed that the immunoassay can be universally used to surveil PPV infection in pig flock. A direct fluorescent assay using PPV-VP2-Nb12-EGFP as a probe was also developed to detect PPV in ST cells. The two developed immunoassays eliminate the use of commercial secondary antibodies and shorten detection time. Meanwhile, both assays display great developmental prospect for further commercial production and application.
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- 2020
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26. Cell Division Control Protein 42 Interacts With Hepatitis E Virus Capsid Protein and Participates in Hepatitis E Virus Infection
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Mengnan Fan, Yuhang Luo, Beibei Zhang, Jiaxi Wang, Tianxiang Chen, Baoyuan Liu, Yani Sun, Yuchen Nan, Julian A. Hiscox, Qin Zhao, and En-Min Zhou
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hepatitis E virus (HEV) ,avian HEV ,CDC42 ,Rho GTPases ,virus-host interaction ,Microbiology ,QR1-502 - Abstract
Hepatitis E Virus (HEV) causes viral hepatitis in humans worldwide, while a subset of HEV species, avian HEV, causes hepatitis-splenomegaly syndrome in chickens. To date, there are few reports on the host proteins interacting with HEV and being involved in viral infection. Previous pull-down assay combining mass spectrometry indicated that cell division control protein 42 (CDC42), a member belonging to the Rho GTPase family, was pulled down by avian HEV capsid protein. We confirmed the direct interaction between CDC42 and avian and mammalian HEV capsid proteins. The interaction can increase the amount of active guanosine triphosphate binding CDC42 state (GTP-CDC42). Subsequently, we determined that the expression and activity of CDC42 were positively correlated with HEV infection in the host cells. Using the different inhibitors of CDC42 downstream signaling pathways, we found that CDC42-MRCK (a CDC42-binding kinase)-non-myosin IIA (NMIIA) pathway is involved in naked avian and mammalian HEV infection, CDC42-associated p21-activated kinase 1 (PAK1)-NMIIA/Cofilin pathway is involved in quasi-enveloped mammalian HEV infection and CDC42-neural Wiskott-Aldrich syndrome protein-actin-polymerizing protein Arp2/3 pathway (CDC42-(N-)WASP-Arp2/3) pathway participates in naked and quasi-enveloped mammalian HEV infection. Collectively, these results demonstrated for the first time that HEV capsid protein can directly bind to CDC42, and non- and quasi-enveloped HEV use different CDC42 downstream signaling pathways to participate in viral infection. The study provided some new insights to understand the life cycle of HEV in host cells and a new target of drug design for combating HEV infection.
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- 2021
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27. Combining Object-Oriented and Deep Learning Methods to Estimate Photosynthetic and Non-Photosynthetic Vegetation Cover in the Desert from Unmanned Aerial Vehicle Images with Consideration of Shadows
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Jie He, Du Lyu, Liang He, Yujie Zhang, Xiaoming Xu, Haijie Yi, Qilong Tian, Baoyuan Liu, and Xiaoping Zhang
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unmanned aerial vehicle (UAV) images ,PV/NPV classification ,shaded features ,deep learning semantic segmentation ,object-oriented technique ,desert ,Science - Abstract
Soil erosion is a global environmental problem. The rapid monitoring of the coverage changes in and spatial patterns of photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV) at regional scales can help improve the accuracy of soil erosion evaluations. Three deep learning semantic segmentation models, DeepLabV3+, PSPNet, and U-Net, are often used to extract features from unmanned aerial vehicle (UAV) images; however, their extraction processes are highly dependent on the assignment of massive data labels, which greatly limits their applicability. At the same time, numerous shadows are present in UAV images. It is not clear whether the shaded features can be further classified, nor how much accuracy can be achieved. This study took the Mu Us Desert in northern China as an example with which to explore the feasibility and efficiency of shadow-sensitive PV/NPV classification using the three models. Using the object-oriented classification technique alongside manual correction, 728 labels were produced for deep learning PV/NVP semantic segmentation. ResNet 50 was selected as the backbone network with which to train the sample data. Three models were used in the study; the overall accuracy (OA), the kappa coefficient, and the orthogonal statistic were applied to evaluate their accuracy and efficiency. The results showed that, for six characteristics, the three models achieved OAs of 88.3–91.9% and kappa coefficients of 0.81–0.87. The DeepLabV3+ model was superior, and its accuracy for PV and bare soil (BS) under light conditions exceeded 95%; for the three categories of PV/NPV/BS, it achieved an OA of 94.3% and a kappa coefficient of 0.90, performing slightly better (by ~2.6% (OA) and ~0.05 (kappa coefficient)) than the other two models. The DeepLabV3+ model and corresponding labels were tested in other sites for the same types of features: it achieved OAs of 93.9–95.9% and kappa coefficients of 0.88–0.92. Compared with traditional machine learning methods, such as random forest, the proposed method not only offers a marked improvement in classification accuracy but also realizes the semiautomatic extraction of PV/NPV areas. The results will be useful for land-use planning and land resource management in the areas.
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- 2022
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28. Overcoming cellulose recalcitrance in woody biomass for the lignin-first biorefinery
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Haibing Yang, Ximing Zhang, Hao Luo, Baoyuan Liu, Tânia M. Shiga, Xu Li, Jeong Im Kim, Peter Rubinelli, Jonathan C. Overton, Varun Subramanyam, Bruce R. Cooper, Huaping Mo, Mahdi M. Abu-Omar, Clint Chapple, Bryon S. Donohoe, Lee Makowski, Nathan S. Mosier, Maureen C. McCann, Nicholas C. Carpita, and Richard Meilan
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Cellulose ,Lignin ,Recalcitrance ,Catalysis ,Delignification ,Poplar ,Fuel ,TP315-360 ,Biotechnology ,TP248.13-248.65 - Abstract
Abstract Background Low-temperature swelling of cotton linter cellulose and subsequent gelatinization in trifluoroacetic acid (TFA) greatly enhance rates of enzymatic digestion or maleic acid–AlCl3 catalyzed conversion to hydroxymethylfurfural (HMF) and levulinic acid (LA). However, lignin inhibits low-temperature swelling of TFA-treated intact wood particles from hybrid poplar (Populus tremula × P. alba) and results in greatly reduced yields of glucose or catalytic conversion compared to lignin-free cellulose. Previous studies have established that wood particles from transgenic lines of hybrid poplar with high syringyl (S) lignin content give greater glucose yields following enzymatic digestion. Results Low-temperature (− 20 °C) treatment of S-lignin-rich poplar wood particles in TFA slightly increased yields of glucose from enzymatic digestions and HMF and LA from maleic acid–AlCl3 catalysis. Subsequent gelatinization at 55 °C resulted in over 80% digestion of cellulose in only 3 to 6 h with high-S-lignin wood, compared to 20–60% digestion in the wild-type poplar hybrid and transgenic lines high in guaiacyl lignin or 5-hydroxy-G lignin. Disassembly of lignin in woody particles by Ni/C catalytic systems improved yields of glucose by enzymatic digestion or catalytic conversion to HMF and LA. Although lignin was completely removed by Ni/C-catalyzed delignification (CDL) treatment, recalcitrance to enzymatic digestion of cellulose from the high-S lines was reduced compared to other lignin variants. However, cellulose still exhibited considerable recalcitrance to complete enzymatic digestion or catalytic conversion after complete delignification. Low-temperature swelling of the CDL-treated wood particles in TFA resulted in nearly complete enzymatic hydrolysis, regardless of original lignin composition. Conclusions Genetic modification of lignin composition can enhance the portfolio of aromatic products obtained from lignocellulosic biomass while promoting disassembly into biofuel and bioproduct substrates. CDL enhances rates of enzymatic digestion and chemical conversion, but cellulose remains intrinsically recalcitrant. Cold TFA is sufficient to overcome this recalcitrance after CDL treatment. Our results inform a ‘no carbon left behind’ strategy to convert total woody biomass into lignin, cellulose, and hemicellulose value streams for the future biorefinery.
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- 2019
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29. Nanobody-horseradish peroxidase fusion protein as an ultrasensitive probe to detect antibodies against Newcastle disease virus in the immunoassay
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Yamin Sheng, Kun Wang, Qizhong Lu, Pinpin Ji, Baoyuan Liu, Jiahong Zhu, Qingyuan Liu, Yani Sun, Jingfei Zhang, En-Min Zhou, and Qin Zhao
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Nanobody ,Nanobody-HRP ,Competitive ELISA ,NDV ,Antibody ,Biotechnology ,TP248.13-248.65 ,Medical technology ,R855-855.5 - Abstract
Abstract Background Sensitive and specific antibodies can be used as essential probes to develop competitive enzyme-linked immunosorbent assay (cELISA). However, traditional antibodies are difficult to produce, only available in limited quantities, and ineffective as enzymatic labels. Nanobodies, which are single-domain antibodies (sdAbs), offer an alternative, more promising tool to circumvent these limitations. In the present work, a cELISA using nanobody-horseradish peroxidase (HRP) fusion protein firstly designed as a probe was developed for detecting anti-Newcastle disease virus (NDV) antibodies in chicken sera. Results In the study, a platform for the rapid and simple production of nanobody-HRP fusion protein was constructed. First, a total of 9 anti-NDV-NP protein nanobodies were screened from a immunised Bactrian camel. Then, the Nb5-HRP fusions were produced with the platform and used for the first time as sensitive reagents for developing cELISA to detect anti-NDV antibodies. The cut-off value of the cELISA was 18%, and the sensitivity and specificity were respectively 100% and 98.6%. The HI test and commercial ELISA kit (IDEXX) separately agreed 97.83% and 98.1% with cELISA when testing clinical chicken sera and both agreed 100% when testing egg yolks. However, for detecting anti-NDV antibodies in the sequential sera from the challenged chickens, cELISA demonstrated to be more sensitive than the HI test and commercial ELISA kit. Moreover, a close correlation (R2 = 0.914) was found between the percent competitive inhibition values of cELISA and HI titers. Conclusions A platform was successfully designed to easily and rapidly produce the nanobody-HRP fusion protein, which was the first time to be used as reagents for establishing cELISA. Results suggest that the platform supports the development of a cELISA with high sensitivity, simplicity, and rapid detection of anti-NDV antibodies. Overall, we believe that the platform based on nanobody-HRP fusions can be widely used for future investigations and treatment other diseases and viruses.
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- 2019
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30. Effect of housing arrangement on fecal-oral transmission of avian hepatitis E virus in chicken flocks
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Baoyuan Liu, Yani Sun, Yiyang Chen, Taofeng Du, Yuchen Nan, Xinjie Wang, Huixia Li, Baicheng Huang, Gaiping Zhang, En-Min Zhou, and Qin Zhao
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Avian HEV ,Housing arrangement ,Virus transmission ,Prevention ,Veterinary medicine ,SF600-1100 - Abstract
Abstract Background Avian hepatitis E virus (HEV) infection is common in chicken flocks in China, as currently no measures exist to prevent the spread of the disease. In this study, we analyzed the effect of caged versus cage-free housing arrangements on avian HEV transmission. First, 127 serum and 110 clinical fecal samples were collected from 4 chicken flocks including the two arrangements in Shaanxi Province, China and tested for HEV antibodies and/or virus. Concurrently, 36 specific-pathogen-free chickens were divided equally into four experimental living arrangement groups, designated cage-free (Inoculated), caged (Inoculated), cage-free (Negative) and caged (Negative) groups. In caged groups, three cages contained 3 chickens each. Three chickens each from cage-free (Inoculated) and caged (Inoculated) groups (one chicken of each cage) were inoculated by cutaneous ulnar vein with the same dose of avian HEV, respectively. The cage-free (Negative) and caged (Negative) groups served as negative control. Serum and fecal samples were collected at 1 to 7 weeks post-inoculation (wpi) and liver lesions were scored at 7 wpi. Results The results of serology showed that the avian HEV infection rate (54.10%) of the cage-free chickens was significantly higher than the one (12.12%) for caged chickens (P
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- 2017
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31. Natural and anthropogenic rates of soil erosion
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Mark A. Nearing, Yun Xie, Baoyuan Liu, and Yu Ye
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Row crop agriculture ,Soil conservation ,Conservation tillage ,No-till ,Residue management ,Permaculture ,Isotopes ,Conservation reserve program ,Northeast China ,National Resource Inventory ,Hugh Hammond Bennett ,Virgin Lands Campaign ,Cerrado ,Beryllium10 ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natural, non-cropped conditions have been documented to be less than 2 Mg ha−1 yr−1. On-site rates of erosion of lands under cultivation over large cropland areas, such as in the United States, have been documented to be on the order of 6 Mg ha−1 yr−1 or more. In northeastern China, lands that were brought into production during the last century are thought to have average rates of erosion over this large area of as much as 15 Mg ha−1 yr−1 or more. Broadly applied soil conservation practices, and in particular conservation tillage and no-till cropping, have been found to be effective in reducing rates of erosion, as was seen in the United States when the average rates of erosion on cropped lands decreased from on the order of 9 Mg ha−1 yr−1 to 6 or 7 Mg ha−1 yr−1 between 1982 and 2002, coincident with the widespread adoption of new conservation tillage and residue management practices. Taking cropped lands out of production and restoring them to perennial plant cover, as was done in areas of the United States under the Conservation Reserve Program, is thought to reduce average erosion rates to approximately 1 Mg ha−1 yr−1 or less on those lands.
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- 2017
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32. Estimating Near-Saturated Soil Hydraulic Conductivity Based on Its Scale-Dependent Relationships with Soil Properties
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Yang Yang, Ole Wendroth, Sleem Kreba, and Baoyuan Liu
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
Soil hydraulic conductivity near saturation () is affected by various soil properties operating at different spatial scales. Using noise-assisted multivariate empirical mode decomposition (NA-MEMD), our objective was to inspect the scale-dependent interactions between and various soil properties and to estimate based on such relationships. In a rectangular field evenly across cropland and grassland, a total of 44 sampling points separated by 5 m were selected and measured for at soil water pressure heads of −1, −5 and −10 cm. At each point, the saturated conductivity was estimated using Gardner’s exponential function, and six soil structural and textural properties were investigated. Decomposed into four intrinsic mode functions (IMFs) and a residue by NA-MEMD, each was found to significantly correlate with all six properties at one spatial scale at least. The variations in were primarily regulated by soil structure, especially at the relatively small scales. Multiple linear regression (MLR) failed to regress either IMF1 or IMF2 of each from the soil properties of the equivalent scales and only accounted for 13.7 to 43.6% of the total variance in calibration for the remaining half of the IMF1s and IMF2s. An artificial neural network was then adopted to estimate IMF1 and IMF2, and the corresponding results were added to the MLR estimates at other scales for which each was estimated at the measurement scale. This prediction greatly outperformed the MLR modeling before NA-MEMD and, on average, accounted for additional 74.4 and 73.4% of the total variance in calibration and validation, respectively. These findings suggest nonlinear correlations between and the soil properties investigated at the small scales and hold important implications for future estimations of and as well as other hydraulic properties.
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- 2019
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33. Human-pathogenic Anaplasma spp., and Rickettsia spp. in animals in Xi'an, China.
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Wen-Ping Guo, Baicheng Huang, Qin Zhao, Gang Xu, Baoyuan Liu, Yi-Han Wang, and En-Min Zhou
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Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
In China, thirteen species of tick-borne rickettsiales bacteria pathogenic to human have been reported in ticks and host animals, and human patients caused by them also has been identified. However, investigation for rickettsiales bacteria circulating in Xi'an wasn't performed although diseases resembling human diseases caused by these organisms have been found. In this study, domestic animals and ticks in Xi'an, China, were tested for the presence of rickettsiales bacteria pathogenic to humans. Besides A. ovis, a high prevalence of A. capra was observed suggesting a high public health risk exists. In addition, two novel Anaplasma species closely related to A. phagocytophilum were identified and formed distinct lineages in the phylogenetic trees, with more than 98.3% identities for rrs gene, while divergences up to 20.2% and 37.0% for groEL and gltA genes, respectively. Both of these two novel Anaplasma species were found to circulate in goats and further assessment of their pathogenicity is needed. Ca. R. jingxinensis, with potential pathogenicity, was also detected in H. longicomis ticks with high prevalence. However, other causative agents were not identified although they were distributed in other areas of China.
- Published
- 2018
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34. Correction to: A nanobody-horseradish peroxidase fusion protein-based competitive ELISA for rapid detection of antibodies against porcine circovirus type 2
- Author
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Yang Mu, Cunyu Jia, Xu Zheng, Haipeng Zhu, Xin Zhang, Haoran Xu, Baoyuan Liu, Qin Zhao, and En-Min Zhou
- Subjects
Biotechnology ,TP248.13-248.65 ,Medical technology ,R855-855.5 - Abstract
An amendment to this paper has been published and can be accessed via the original article.
- Published
- 2021
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35. Monitoring and predicting the soil water content in the deeper soil profile of Loess Plateau, China
- Author
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Aijuan Wang, Baoyuan Liu, Zhiqiang Wang, and Gang Liu
- Subjects
Clay content ,Field capacity ,Sand content ,Soil water content (SWC) ,Soil particle size ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Estimation of soil water content (SWC) in deep soil profiles is of crucial importance for strategic management of water resource for sustainable land use in arid and semi-arid zones, as well as for soil and water conservation. Soil properties have a very important effect on SWC. This study aimed to analyze the influence of soil particle size on SWC, for the first time using soil particle size to estimate SWC in deep soil profiles. SWC was measured mainly in farmland, natural grasslands and plantations of Caragana from the surface to more than 20 m depth. The same soil samples were also tested for particle size. The results show that the soil desiccation is formed in the caragana forest in 3–18 m soil layers, but almost no formation in 18–24 m layers; water content of farmland and grassland is different in all soil profiles although they are both shallow rooted plants. Correlation analysis indicated that SWC could be well predicted by clay content and the close correlation between SWC and clay content yielded a coefficient of determination (R2) of 0.82 and 0.72, respectively, for farmland and grassland. After multiple regression analysis, a regression model was built using SWC, clay content and sand content data, giving R2=0.66. The model provided reliable estimates of SWC profile based on textural class. This can assist in estimating water depletion by vegetation, by comparing moisture of farmland and grassland soils with that of plantation forests, and in selecting sustainable land use of arid land.
- Published
- 2016
- Full Text
- View/download PDF
36. An Experimental Study on Field Spectral Measurements to Determine Appropriate Daily Time for Distinguishing Fractional Vegetation Cover
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Du Lyu, Baoyuan Liu, Xiaoping Zhang, Xihua Yang, Liang He, Jie He, Jinwei Guo, Jufeng Wang, and Qi Cao
- Subjects
fractional vegetation cover ,field spectral measurement ,spectral indices ,appropriate measurement time ,Science - Abstract
Remote sensing technology has been widely used to estimate fractional vegetation cover (FVC) at global and regional scales. Accurate and consistent field spectral measurements are required to develop and validate spectral indices for FVC estimation. However, there are rarely any experimental studies to determine the appropriate times for field spectral measurements, and the existing guidelines or references are rather general or inconsistent, it is still not agreed upon and detailed experiments are missing for a local research. In this experiment, five groundcover objects were measured continuously from 07:30 a.m. to 17:30 p.m. local time in three consecutive sunny days using a portable spectrometer. The coefficients of variation (CV) were applied to investigate the reflectance variation at wavelengths corresponding to MODIS satellite channels and the derived spectral indices used to estimate FVC, including photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV). The results reveal little variation in the reflectance measured between 10:00 a.m. and 16:00 p.m., with CV values generally less than 10%. The CV values of FVC spectral indices for estimating PV, NPV and bare soil (BS) are generally less than 3%. While more experiments are yet to be carried out at different locations and in different seasons, the findings so far imply that the in situ spectrum measured between 9:00 a.m. and 17:00 p.m. local time would be useful to discriminate FVC objects and validate satellite estimates-based indices using visible, near-infrared and shortwave infrared channels.
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- 2020
- Full Text
- View/download PDF
37. Synthetic Peptides Containing Three Neutralizing Epitopes of Genotype 4 Swine Hepatitis E Virus ORF2 induced Protection against Swine HEV Infection in Rabbit
- Author
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Yiyang Chen, Tianxiang Chen, Yuhang Luo, Jie Fan, Meimei Zhang, Qin Zhao, Yuchen Nan, Baoyuan Liu, and En-Min Zhou
- Subjects
hepatitis E virus ,swine HEV ,neutralizing epitopes ,synthetic peptides ,Medicine - Abstract
Genotype 4 hepatitis E virus (HEV) is a zoonotic pathogen transmitted to humans through food and water. Previously, three genotype 4 swine HEV ORF2 peptides (407EPTV410, 410VKLYTS415, and 458PSRPF462) were identified as epitopes of virus-neutralizing monoclonal antibodies that partially blocked rabbit infection with swine HEV. Here, individual and tandem fused peptides were synthesized, conjugated to keyhole limpet hemocyanin (KLH), then evaluated for immunoprotection of rabbits against swine HEV infection. Forty New Zealand White rabbits were randomly assigned to eight groups; groups 1 thru 5 received three immunizations with EPTV-KLH, VKLYTS-KLH, PSRPF-KLH, EPTVKLYTS-KLH, or EPTVKLYTSPSRPF-KLH, respectively; group 6 received truncated swine HEV ORF2 protein (sp239), and group 7 received phosphate-buffered saline. After an intravenous swine HEV challenge, all group 7 rabbits exhibited viremia and fecal virus shedding by 2–4 weeks post challenge (wpc), seroconversion by 4–9 wpc, elevated alanine aminotransferase (ALT) at 2 wpc, and severe liver lymphocytic venous periphlebitis. Only 1–2 rabbits/group in groups 1–4 exhibited delayed viremia, fecal shedding, seroconversion, increased ALT levels, and slight liver lymphocytic venous periphlebitis; groups 5–6 showed no pathogenic effects. Collectively, these results demonstrate that immunization with a polypeptide containing three genotype 4 HEV ORF2 neutralizing epitopes completely protected rabbits against swine HEV infection.
- Published
- 2020
- Full Text
- View/download PDF
38. A China data set of soil properties for land surface modeling
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Wei Shangguan, Yongjiu Dai, Baoyuan Liu, Axing Zhu, Qingyun Duan, Lizong Wu, Duoying Ji, Aizhong Ye, Hua Yuan, Qian Zhang, Dongdong Chen, Ming Chen, Jianting Chu, Youjun Dou, Jianxia Guo, Haiqin Li, Junjia Li, Lu Liang, Xiao Liang, Heping Liu, Shuyan Liu, Chiyuan Miao, and Yizhou Zhang
- Subjects
land surface modeling ,soil attribute database ,soil polygon linkage ,china soil characteristics data set ,Physical geography ,GB3-5030 ,Oceanography ,GC1-1581 - Abstract
A comprehensive 30×30 arc‐second resolution gridded soil characteristics data set of China has been developed for use in the land surface modeling. It includes physical and chemical attributes of soils derived from 8979 soil profiles and the Soil Map of China (1:1,000,000). We used the polygon linkage method to derive the spatial distribution of soil properties. The profile attribute database and soil map are linked under the framework of the Genetic Soil Classification of China which avoids uncertainty in taxon referencing. Quality control information (i.e., sample size, soil classification level, linkage level, search radius and texture) is included to provide “confidence” information for the derived soil parameters. The data set includes 28 attributes for 8 vertical layers at the spatial resolution of 30×30 arc‐seconds. Based on this data set, the estimated storage of soil organic carbon in the upper 1 m of soil is 72.5 Pg, total N is 6.6 Pg, total P is 4.5 Pg, total K is 169.9 Pg, alkali‐hydrolysable N is 0.55 Pg, available P is 0.03 Pg, and available K is 0.61 Pg. These estimates are reasonable compared with previous studies. The distributions of soil properties are consistent with common knowledge of Chinese soil scientists and the spatial variations over large areas are well represented. The data set can be incorporated into land models to better represent the role of soils in hydrological and biogeochemical cycles in China.
- Published
- 2013
- Full Text
- View/download PDF
39. A Novel Blocking ELISA for Detection of Antibodies against Hepatitis E Virus in Domestic Pigs.
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Yiyang Chen, Qin Zhao, Baoyuan Liu, Lizhen Wang, Yani Sun, Huixia Li, Xinjie Wang, Shahid Faraz Syed, Gaiping Zhang, and En-Min Zhou
- Subjects
Medicine ,Science - Abstract
Hepatitis E virus (HEV) infects both humans and animals, with an overall human mortality rate generally less than 1%, but as high as 20% among pregnant women. HEV strains fall into 4 major genotypes. Zoonotic genotypes 3 and 4 associate with sporadic human and animal HEV cases in many industrialized countries. To date, collective evidence implicates pigs as the main HEV reservoir, justifying the importance of monitoring HEV infection rates in pig herds to prevent human illness. Due to the lack of a robust in vitro cell culture system for viral propagation, no "gold standard" assay has yet been developed to detect HEV infection in domestic pigs. 1E4, a monoclonal antibody (mAb) specific for the C-terminal 268 amino acids of HEV genotype 4 ORF2 capsid protein (sORF2-C), was generated and conjugated to horseradish peroxidase (HRP) for use in a blocking ELISA (bELISA). Optimal sORF2-C coating antigen concentration (8 μg/ml), HRP-1E4 dilution (1:1000), and test pig serum dilution (1:20) were determined using a checkerboard titration test. A cut-off value of 16.9% was chosen to differentiate between positive vs. negative sera after mean percent inhibition (PI) testing of 230 negative pig sera. Compared with the indirect ELISA (iELISA), western blot, and a commercial ELISA kit for detecting anti-HEV antibodies in human sera, the bELISA showed no statistical differences and statistically high coincidence of 93.23%, 92%, and 95% with the other tests, respectively. A blocking ELISA (bELISA) for detecting anti-HEV antibodies in pig serum samples was developed with high sensitivity and high specificity comparable to that of the indirect ELISA. The bELISA results exhibited high agreement with iELISA, western blot, and a commercial ELISA kit designed to detect human anti-HEV antibodies. Therefore, bELISA should serve as an ideal method for large-scale serological investigation of anti-HEV antibodies in domestic pigs.
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- 2016
- Full Text
- View/download PDF
40. Effectiveness and Durability of Polyacrylamide (PAM) and Polysaccharide (Jag C 162) in Reducing Soil Erosion under Simulated Rainfalls
- Author
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Shaojuan Lu, Zhanli Wang, Yaxian Hu, Baoyuan Liu, and Jun’e Liu
- Subjects
polyacrylamide ,polysaccharide ,soil erosion ,runoff ,sediment concentration ,soil aggregate ,Hydraulic engineering ,TC1-978 ,Water supply for domestic and industrial purposes ,TD201-500 - Abstract
Polymers as a soil amendment is one of the effective measurements to reduce soil erosion. In this study, two polymers, polyacrylamide (PAM) and polysaccharide (Jag C 162), were applied to erosion plots filled with loess soil (tilted at 20°). For each polymer, four concentration levels—0, 10, 30, and 50 kg·ha−1—were applied. The treated erosion plots were then subjected to two simulated rainfall events (dry and wet run) to investigate their effectiveness and durability in controlling soil erosion. Both simulated rainfall events were at an intensity of 120 mm·h−1, and each event lasted for 30 min with 24 h free drainage in between. Results show that both polymers could reduce runoff, effectively control sheet erosion, and promote soil aggregates due to their capability to bind and stabilize soil particles. Such reducing effects were more pronounced on the Jag C 162-treated plots than on the PAM-treated plots. However, during the second (wet) run, there was more reduction of aggregate with size of >0.25 mm and greater increment of soil loss on the Jag C 162-treated plots than on the PAM-treated plots.
- Published
- 2018
- Full Text
- View/download PDF
41. Wide Hidden Expansion Layer for Deep Convolutional Neural Networks.
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Min Wang, Baoyuan Liu, and Hassan Foroosh
- Published
- 2020
- Full Text
- View/download PDF
42. Combining Object-Oriented and Deep Learning Methods to Estimate Photosynthetic and Non-Photosynthetic Vegetation Cover in the Desert from Unmanned Aerial Vehicle Images with Consideration of Shadows.
- Author
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Jie He, Du Lyu, Liang He, Yujie Zhang, Xiaoming Xu, Haijie Yi, Qilong Tian, Baoyuan Liu, and Xiaoping Zhang
- Published
- 2023
- Full Text
- View/download PDF
43. Look-Up Table Unit Activation Function for Deep Convolutional Neural Networks.
- Author
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Min Wang, Baoyuan Liu, and Hassan Foroosh
- Published
- 2018
- Full Text
- View/download PDF
44. Opportunities in Closed-Loop Molecular Recycling of End-of-Life Polyurethane
- Author
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Baoyuan Liu, Zach Westman, Kelsey Richardson, Dingyuan Lim, Alan L. Stottlemyer, Thomas Farmer, Paul Gillis, Vojtech Vlcek, Phillip Christopher, and Mahdi M. Abu-Omar
- Subjects
Renewable Energy, Sustainability and the Environment ,General Chemical Engineering ,Environmental Chemistry ,General Chemistry - Published
- 2023
45. Factorized Convolutional Neural Networks.
- Author
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Min Wang, Baoyuan Liu, and Hassan Foroosh
- Published
- 2017
- Full Text
- View/download PDF
46. Study of High Resolution Helicopter Cable Obstacle Avoidance LIDAR
- Author
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Xiangwei Zhang, Qun Ma, Yujiao Chen, Changmei Gong, Baoyuan Liu, Feng Han, and Xun Yu
- Abstract
A high-resolution helicopter cable obstacle avoidance LIDAR is designed by the laser parallel scanning method, combined with the 3×2 rectangular detector array, which greatly reduces the conventional laser radar in the detection of the cable blind area. By simulating the actual detection state of helicopter through the UAV hanging-off test, the cable at 150m is clearly detected at the data refresh rate of 2Hz. Through the range detection test, it is verified that the detection distance of the system for φ20 cable is more than 283m.
- Published
- 2023
47. Using CSLE to find the dominant factor in the change of soil erosion in the past 50 years on the Chinese Loess Plateau
- Author
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Liang He, Xiaoping Zhang, Baoyuan Liu, Gema Guzmán, and José A Gómeza
- Abstract
Once one of the most severe soil loss regions worldwide, the Chinese Loess Plateau has experienced large-scale land use changes and vegetation restoration in the past few decades. Understanding how land use change affects soil erosion is critical in the region's ecological construction and land management. In this study, the Beiluo River Basin covering 26,905 km2 in the hinterland of the Loess Plateau was selected to investigate vegetation restoration and its impacts on soil loss rates over the last 50 years. Results show that land use in the basin has changed considerably, mainly reflected in the upper reaches. From 1970–2020, cropland in the upper reaches decreased by 54%, directly leading to a 9.1-fold increase in forested land. Landsat-NDVI shows vegetation coverage increased from 21.1% to 69.9% over time. Vegetation coverage changed from 48.1% to 78.7% for the entire basin. The Chinese Soil Loss Equation (CSLE) was used and confirmed to be satisfactory with a high coefficient of determination (R2, 0.89) and a strong Nash–Sutcliffe efficiency coefficient (0.72), although an underestimation exists. With the change in land use, the specific soil loss simulated in the upper reaches maintained a high rate of around 8,000 t·km−2·yr−1 from the 1970s to the 1990s, dramatically dropping to 3,058 t·km−2·yr−1 in the 2000s, then attenuated to 1,321 t·km−2·yr−1 in the 2020s. For the entire basin, soil loss rates dropped from 4,090 to 1,848 and 890 t·km−2·yr−1 from the 1970s to the 2000s and 2020s, respectively. Attribution analysis showed that the dominant factor in the change in soil loss rates in the 1980s and 1990s relative to the 1970s was the change in rainfall erosivity for the entire watershed. However, with vegetation coverage increasing to 59.0% in the 2000s, vegetation restoration rapidly converted to the dominant factor contributing 78.3% to soil loss decrease in that period. With expanding vegetation cover, its contribution grew to 84.9% in the 2020s. The shift is evident in each reach of the basin except the terrain-plain area with the majority of farmland. The findings are helpful for sustainable land use planning and socio-economic development on the Loess Plateau and in similar areas.
- Published
- 2023
48. Understanding the variability and stability of hydrological components under vegetation restoration in watersheds on the Chinese Loess Plateau in past 50 years
- Author
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Xiaoping Zhang, Haijie Yi, Fan Xue, Leendert Adrian Bruijnzeel, Zhuo Cheng, Baoyuan Liu, and Yangyang Li
- Abstract
Assessing ecological restoration effects on hydrological regimes is important for watershed management, especially under semi-arid conditions. The long-term trends of streamflow components were analyzed for three less forested watersheds (LFWs), and for two largely forested watersheds (FWs) within the Beiluo River Basin on the Chinese Loess Plateau. Three LFWs were undergoing major vegetation restoration, in which the vegetation coverage changed from 16–23% in 1970 to 57–80% coverage in 2019. While as contrast, the two FWs has vegetation coverage from 65–68% in 1970 to 88–92% in 2019. Daily flow data for each watershed and year were normalized by rainfall to eliminate effects of non-stationary rainfall. Mean annual streamflow totals for the ~60-year study period were 25.1–34.1 and 21.6–48.1 mm y_1 for the LFWs and FWs, respectively. Average contributions of baseflow to total streamflow were 32–44% for the LFWs and 58–61% for the FWs. Mann-Kendall tests showed significant decreasing trends for annual streamflow and stormflow (0.23–0.54% y_1) from the LFWs throughout. Mean streamflow from the LFWs between 2000 and 2019 decreased by 58% compared to the pre-2000 period, while the average contribution of stormflow decreased from 66% to 35% (2010s). However, winter baseflow increased with time since start of restoration. Conversely, streamflow (components) for the FWs showed only slight fluctuations in decadal, annual and seasonal trends. Both total streamflow and stormflow exhibited strong power relationships with vegetation coverage, illustrating a tendency towards stable flow regimes for vegetation coverage >60–70%. Large-scale vegetation restoration has fundamentally changed amounts and temporal distribution of streamflow (components) on the Loess Plateau mainly by regulating stormflow. After 20 years of restoration, the trend and proportion of streamflow components from the LFWs approximated those of the FWs. Since soil erosion is driven by a certain of amount and intensity of runoff, the above results imply that soil erosion and sediment transportation would reach a stability with vegetation restoration to a certain coverage in watersheds. But it is necessary to investigate the difference among regions. These results underpin the planning of sustainable management of natural resources and socio-economic development during long term ecological restoration on the Loess Plateau.Keywords: Trends of long-term hydrological elements; Surface flow and baseflow; Vegetation restoration; Loess Plateau
- Published
- 2023
49. Sparse Convolutional Neural Networks.
- Author
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Baoyuan Liu, Min Wang, Hassan Foroosh, Marshall F. Tappen, and Marianna Pensky
- Published
- 2015
- Full Text
- View/download PDF
50. Effects of different vegetation restoration types on soil hydro-physical properties in the hilly region of the Loess Plateau, China
- Author
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Du Lyu, Yahui Yang, Wenhui Zhao, Xiaoming Xu, Liang He, Jinwei Guo, Siyue Lei, Baoyuan Liu, and Xiaoping Zhang
- Subjects
Soil Science ,Environmental Science (miscellaneous) ,Earth-Surface Processes - Abstract
Context Severe soil erosion in the Chinese Loess Plateau and the resulting high sediment yield of the Yellow River have been important research topics. Aims Understanding the impacts of vegetation types on soil hydro-physical properties is essential for understanding regional runoff-sediment changes, soil and water conservation, and revegetation. Methods Three main plantation covers of the study area [natural restoration grassland (NG), artificial Prunus armeniaca forest (AP), and artificial Hippophae rhamnoides shrubland (AH) with 15 years of restoration] and Sorghum bicolor agricultural land as control (CK), were selected to compare their soil hydro-physical properties and infiltration capacity in the soil profile. Key results The bulk density was lower, and soil organic matter (SOM), the proportion of macro-aggregates (>5 mm), mean weight diameter (MWD) of water-stable aggregates, and the initial infiltration and stable infiltration rate were higher in the AH plot compared to CK and the other two plots. The impacts of vegetation restoration on soil properties were mainly in the 0–60 cm layer. Infiltration rates changed mainly within 5 h and basically stabilised within 10 h, with even shorter times to reach stable infiltration in CK. The initial and stable infiltration rates were significant positively correlated (P
- Published
- 2022
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