109 results on '"Shimin Xu"'
Search Results
2. Combined gestational age and serum fucose for early prediction of risk for bronchopulmonary dysplasia in premature infants
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Liangliang Li, Shimin Xu, Miaomiao Li, Xiangyun Yin, Hongmin Xi, Ping Yang, Lili Ma, Lijuan Zhang, and Xianghong Li
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Bronchopulmonary dysplasia ,Serum monosaccharides ,Monosaccharide composite (MC) ,High-performance liquid chromatography ,Prediction model ,Pediatrics ,RJ1-570 - Abstract
Abstract Objective As the predominant complication in preterm infants, Bronchopulmonary Dysplasia (BPD) necessitates accurate identification of infants at risk and expedited therapeutic interventions for an improved prognosis. This study evaluates the potential of Monosaccharide Composite (MC) enriched with environmental information from circulating glycans as a diagnostic biomarker for early-onset BPD, and, concurrently, appraises BPD risk in premature neonates. Materials and methods The study incorporated 234 neonates of ≤32 weeks gestational age. Clinical data and serum samples, collected one week post-birth, were meticulously assessed. The quantification of serum-free monosaccharides and their degraded counterparts was accomplished via High-performance Liquid Chromatography (HPLC). Logistic regression analysis facilitated the construction of models for early BPD diagnosis. The diagnostic potential of various monosaccharides for BPD was determined using Receiver Operating Characteristic (ROC) curves, integrating clinical data for enhanced diagnostic precision, and evaluated by the Area Under the Curve (AUC). Results Among the 234 neonates deemed eligible, BPD development was noted in 68 (29.06%), with 70.59% mild (48/68) and 29.41% moderate-severe (20/68) cases. Multivariate analysis delineated several significant risk factors for BPD, including gestational age, birth weight, duration of both invasive mechanical and non-invasive ventilation, Patent Ductus Arteriosus (PDA), pregnancy-induced hypertension, and concentrations of two free monosaccharides (Glc-F and Man-F) and five degraded monosaccharides (Fuc-D, GalN-D, Glc-D, and Man-D). Notably, the concentrations of Glc-D and Fuc-D in the moderate-to-severe BPD group were significantly diminished relative to the mild BPD group. A potent predictive capability for BPD development was exhibited by the conjunction of gestational age and Fuc-D, with an AUC of 0.96. Conclusion A predictive model harnessing the power of gestational age and Fuc-D demonstrates promising efficacy in foretelling BPD development with high sensitivity (95.0%) and specificity (94.81%), potentially enabling timely intervention and improved neonatal outcomes.
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- 2024
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3. Spatiotemporal Variation Characteristics and Source Identification of Nitrogen in the Baiyangdian Lake Water, China
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Qianqian Zhang, Shimin Xu, and Li Yang
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lakes ,nitrogen ,water quality ,source identification ,principal component analysis ,Hydraulic engineering ,TC1-978 ,Water supply for domestic and industrial purposes ,TD201-500 - Abstract
To study the characteristics and sources of nitrogen in the Baiyangdian Lake, this research conducted water quality monitoring during three hydrological periods (normal period, flood period, and dry period), and 165 pieces of routine water quality monitoring data were collected from the three national control sections for Baiyangdian Lake and its inflow rivers. By integrating water chemical analysis with multivariate statistical techniques, the study comprehensively investigated the spatiotemporal variation patterns of nitrogen in Baiyangdian Lake and identified the sources of nitrogen pollution. The results showed that the concentration of total nitrogen (TN) was highest during the dry period, reaching an average of 0.924 mg/L, and 31.3% of the sites exceeded the national Grade III surface water quality standard, reflecting a potential risk of nitrogen pollution. Based on the ion ratio method and principal component analysis (PCA), the main sources of nitrogen pollution in Baiyangdian Lake were identified as manure and domestic sewage, with agricultural fertilizers also having a certain impact on water nitrogen pollution. In addition, the study also compared the nitrogen concentration in Baiyangdian Lake with several important lakes in China. The results showed that the concentrations of TN and ammonium nitrogen (NH4+-N) in Baiyangdian Lake are lower than those in lakes in areas with similar human activity intensity, indicating that the water quality of Baiyangdian is relatively good. This study can provide a scientific basis for water quality management and pollution prevention for Baiyangdian Lake.
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- 2024
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4. Optimal deployment of the online monitoring equipment at the edges of substations considering spatial constraint
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Wenxiang Xu, Shaocong Tong, Shimin Xu, Baigang Du, Dezheng Liu, and Tao Qin
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Mechanical engineering and machinery ,TJ1-1570 - Abstract
To realize the optimal deployment of online monitoring equipment at the edges of substations under the cloud-edge collaboration framework, an optimal deployment model of edges considering spatial constraints is proposed. In the model, the constraints including edge deployment point, line of sight, as well as device pose, etc. are taken into account. To achieve the one-to-many collection of the deployed equipment, a mathematical model is constructed with the objectives of minimizing the shooting distance and the number of edge equipments. And an archive based multi-objective simulated annealing algorithm based on improved trending Markov chain (IAMOSA) is proposed to solve the problem. This algorithm utilizes greedy clustering to initialize deployment points, and the improved disturbance step length with tendency is used to search the neighborhood space. Besides, polynomial fitting Pareto front is also used to select and guide the Markov chain and archive population. Finally, the feasibility and effectiveness of the proposed model and algorithm are verified through an experiment of optimal deployment of the edge equipments in a certain substation.
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- 2024
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5. Improved Scheme for Data Aggregation of Distributed Oracle for Intelligent Internet of Things
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Ruiyang Gao, Yongtao Xue, Wei Wang, Yin Lu, Guan Gui, and Shimin Xu
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blockchain ,data privacy ,homomorphic encryption ,Internet of Things ,Oracle ,Chemical technology ,TP1-1185 - Abstract
Oracle is a data supply mechanism that provides real-world data for blockchain. It serves as a bridge between blockchain and the IoT world, playing a crucial role in solving problems such as data sharing and device management in the IoT field. The main challenge at this stage is determining how to achieve data privacy protection in distributed Oracle machines to safeguard the value hidden in data on the blockchain. In this paper, we propose an improved scheme for distributed Oracle data aggregation based on Paillier encryption algorithm, which achieves end-to-end data privacy protection from devices to users. To address the issue of dishonest distributed Oracle machines running out of funds, we have designed an algorithm called PICA (Paillier-based InChain Aggregation). Based on the aggregation on the Chainlink chain and the Paillier encryption algorithm, random numbers are introduced to avoid the problem of dishonest Oracle machines running out of funds. We use the traffic coverage method to solve the problem of exposed request paths in distributed Oracle machines. Simulation and experimental results show that in small and medium-sized IoT application scenarios with 10,000 data nodes, each additional false request in a single request will result in a delay of about 2 s in data acquisition and can achieve a request response time of 20 s. The proposed method can achieve user data privacy protection.
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- 2024
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6. Adaptive Transferring Method of Digital Twin Model for Machining Domain
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SHEN Hui, LIU Shimin, XU Minjun, HUANG Delin, BAO Jingsong, ZHENG Xiaohu
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digital twin ,quality prediction ,change of working conditions ,transfer learning ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Chemical engineering ,TP155-156 ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 - Abstract
In the multi-variety and small batch manufacturing workshop, digital twin model is mostly established for specific scenarios. Due to its lack of adaptive ability under working conditions, the prediction accuracy of machining quality is insufficient. To solve this problem, an adaptive transferring method of the digital twin model is proposed. By building the transferable digital twin model, the online prediction of machining quality based on the fusion of mechanism and algorithm model is realized. The transferring process and strategy of the digital twin model are proposed. Based on the analysis and calculation of characteristic data, the source model to be transferred is selected. At the same time, in combination with the transfer learning theory, the transfer of digital twin models is realized under simple and complex changing conditions. Taking drilling as an example, the drilling experiment platform is built and the feasibility of digital twin model transfer is verified. The results show that the model can keep the mean absolute error of prediction less than 1.5% under changing working conditions. This method provides a new idea to improve the adaptive ability of digital twin models.
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- 2022
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7. A comparative study in healthy and diabetic mice followed the exposure of polystyrene microplastics: Differential lipid metabolism and inflammation reaction
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Su Liu, Zhizhi Wang, Qi Xiang, Bing Wu, Wang Lv, and Shimin Xu
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Polystyrene microplastics (PS-MPs) ,Diabetic mice ,Lipid metabolism ,Inflammation ,Environmental pollution ,TD172-193.5 ,Environmental sciences ,GE1-350 - Abstract
Human exposure to microplastics (MPs) continues to occur due to ingestion of contaminated food, water and air. Intake of MPs can pose potential health risks by interfering with the production and circulation of nutrients, leading to physiological stress (such as immune responses and metabolic abnormalities). Toxicity data of MPs based on healthy individuals may not be applicable to large populations of patients with chronic diseases represented by diabetes. Therefore, in this study, the response of diabetic mice was compared with that of healthy mice after exposure to polystyrene microplastics (PS-MPs), and interesting differences were observed. PS-MPs exposure significantly increased liver tissue damage, abnormal lipid metabolism, inflammatory effect, liver metabolic disorder and changes of intestinal microbial composition in diabetic mice. Moreover, PS-MPs overstated abnormal lipid metabolism in diabetic mice. The difference between the increased inflammation after exposure to PS-MPs in healthy and diabetic mice involves that the former is mainly modulated by gut microbes, while diabetic mice seem to be more susceptible to lipid metabolism disturbances. In addition, the size effect of MPs was also observed in diabetic mice. These results suggested that individuals with chronic diseases may be more sensitive to pollution due to altered homeostasis, and therefore disease status should be fully considered when assessing the health risk of pollutants.
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- 2022
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8. GmbZIP1 negatively regulates ABA-induced inhibition of nodulation by targeting GmENOD40–1 in soybean
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Shimin Xu, Shanshan Song, Xiaoxu Dong, Xinyue Wang, Jun Wu, Ziyin Ren, Xuesong Wu, Jingjing Lu, Huifang Yuan, Xinying Wu, Xia Li, and Zhijuan Wang
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ABA ,Nodulation ,GmbZIP1 ,GmENOD40–1 ,Soybean ,Botany ,QK1-989 - Abstract
Abstract Background Abscisic acid (ABA) plays an important role in plant growth and adaptation through the ABA signaling pathway. The ABA-responsive element binding (AREB/ABF) family transcriptional factors are central regulators that integrate ABA signaling with various signaling pathways. It has long been known that ABA inhibits rhizobial infection and nodule formation in legumes, but the underlying molecular mechanisms remain elusive. Results Here, we show that nodulation is very sensitive to ABA and exogenous ABA dramatically inhibits rhizobial infection and nodule formation in soybean. In addition, we proved that GmbZIP1, an AREB/ABF transcription factor, is a major regulator in both nodulation and plant response to ABA in soybean. GmbZIP1 was specifically expressed during nodule formation and development. Overexpression of GmbZIP1 resulted in reduced rhizobial infection and decreased nodule number. Furthermore, GmbZIP1 is responsive to ABA, and ectopic overexpression of GmbZIP1 increased sensitivity of Arabidopsis plants to ABA during seed germination and postgerminative growth, and conferred enhanced drought tolerance of plants. Remarkably, we found that GmbZIP1 directly binds to the promoter of GmENOD40–1, a marker gene for nodule formation, to repress its expression. Conclusion Our results identified GmbZIP1 as a node regulator that integrates ABA signaling with nodulation signaling to negatively regulate nodule formation.
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- 2021
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9. FOCES: Detecting Forwarding Anomalies in Software Defined Networks.
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Peng Zhang 0011, Shimin Xu, Zuoru Yang, Hao Li 0011, Qi Li 0002, Huanzhao Wang, and Chengchen Hu
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- 2018
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10. Study on Interchanges among Atmospheric, Surface Unsaturated Soil and Groundwater under the Conditions of Vegetation
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Dezhen, Zhang, primary and Shimin, Xu, additional
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- 2020
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11. Liquid-Liquid Equilibria and Mechanism Analysis For Separating Phenol from Coal Tar Containing Toluene Using 1,2-Propanediol or 1,3-Propanediol
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Chong Yang, Yuyao Xie, Shimin Xu, Hui Wang, Lihua Cheng, and Xinping Ouyang
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- 2023
12. Combined Gestational Age and Serum Fucose for Early Prediction of Risk for Bronchopulmonary Dysplasia in Premature Infants
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Liangliang Li, Shimin Xu, Xiangyun Yin, Hongmin Xi, Ping Yang, Lili Ma, Lijuan Zhang, and Xianghong Li
- Abstract
Objective: Bronchopulmonary dysplasia (BPD) is the most complication of premature infants, accurate identification of at-risk infants and early intervention are key to improve outcomes. The objective of this study is to explore a multifactorial model to predict the risk of BPD. Materials and methods: A total of 148 neonates with gestational age ≤ 32 weeks were recruited. Clinical data and serum samples at 1week after birth were collected. Content of serum free monosaccharides and degraded monosaccharides were analyzed by high-performance liquid chromatography (HPLC). The logistic regression analysis was drawn to build models for the early diagnosis of BPD. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic value of different monosaccharides for BPD, and combined with clinical data to improve the diagnostic efficiency, which was calculated using the area under the curve (AUC). Results: Of the 148 eligible infants, 42 developed BPD (28.38%), which consist of 71.43% mild (30/42) and 28.57%moderate-severe (12/42) cases. The significant risk factors for BPD in the multivariate analysis of clinical data and serum monosaccharides were gestational age, birth-weight, the duration of invasive mechanical ventilation and non-invasive ventilation, patient ductus arteriosus (PDA) and pregnancy-induced hypertension, glucose (Glc-F), mannose (Man-F), fucose (Fuc-D), galactosamine (GalN-D), galactose (Gal-D), glucose (Glc-D) and mannose (Man-D). In addition, the concentration of Glc-D and Fuc-D inmoderate-severe BPD group were significantly lower than those in mild BPD group. The combination of gestational age and Fuc-D determined the risk of developing BPD, with an AUC value of 0.9964. Conclusion: The prediction model based on the gestational age and Fuc-D predicts the development of BPD with high sensitivity (95.24%) and specificity (93.24%) and might facilitate early intervention and improve outcome.
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- 2022
13. GAI Functions in the Plant Response to Dehydration Stress in Arabidopsis thaliana
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Zhijuan Wang, Liu Liu, Chunhong Cheng, Ziyin Ren, Shimin Xu, and Xia Li
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drought ,ga ,della ,abf2 ,protein–protein interaction ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
DELLA (GAI/RGA/RGL1/RGL2/RGL3) proteins are key negative regulators in GA (gibberellin) signaling and are involved in regulating plant growth as a response to environmental stresses. It has been shown that the DELLA protein PROCERA (PRO) in tomato promotes drought tolerance, but its molecular mechanism remains unknown. Here, we showed that the gai-1 (gibberellin insensitive 1) mutant (generated from the gai-1 (Ler) allele (with a 17 amino acid deletion within the DELLA domain of GAI) by backcrossing gai-1 (Ler) with Col-0 three times), the gain-of-function mutant of GAI (GA INSENSITIVE) in Arabidopsis, increases drought tolerance. The stomatal density of the gai-1 mutant was increased but its stomatal aperture was decreased under abscisic acid (ABA) treatment conditions, suggesting that the drought tolerance of the gai-1 mutant is a complex trait. We further tested the interactions between DELLA proteins and ABF2 (abscisic acid (ABA)-responsive element (ABRE)-binding transcription factors) and found that there was a strong interaction between DELLA proteins and ABF2. Our results provide new insight into DELLA proteins and their role in drought stress tolerance.
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- 2020
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14. Equalization Measurement and Optimization of the Public Cultural Facilities Distribution in Tianjin Central Area
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Sheng Zhang, Shimin Xu, Da Wan, Hui Liu, Lin Zhao, Lian Guo, and Juan Ren
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Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,spatial equalization ,public cultural facilities ,Tianjin central area ,supply-demand coupling coordination model ,distribution optimization ,Building and Construction ,Management, Monitoring, Policy and Law - Abstract
In the context of urban stock renewal, the spatial arrangement of public cultural facilities (PCFs) should follow the principles of equity and efficiency to ensure that residents have equitable access to and quality of public cultural services. The aim of this article is to study the spatial distribution of PCFs and the coupling of supply and demand of cultural resources in Tianjin’s central area. By building a supply-demand coupling coordination model and other methods, the equalization of the spatial distribution of PCFs is measured from various perspectives, and the results suggest that more than half of the sub-districts are in a situation of supply and demand imbalance. To fulfill the purpose of meeting residents’ actual needs, balancing supply and demand for cultural resources, and coordinating the increase in stock, these sub-districts’ facilities enter the step of optimization. Depending on the circumstances, the quality and scale of these facilities are optimized, or new facility points are added based on the maximized coverage model. The optimization is shown to be beneficial in terms of updating design and coverage quantity using two real-world cases. Finally, the coverage of facilities in the study area is maximized, facility utilization is made more efficient, and residents’ needs for public cultural services are satisfied.
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- 2023
15. Discrete Element Modeling of the Nayong Rock Avalanche, Guizhou, China Constrained by Dynamic Parameters from Seismic Signal Inversion
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Kaiping Jin, Shimin Xu, Yu Zhuang, Hao Luo, and Aiguo Xing
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Hazard (logic) ,Seismometer ,geography ,geography.geographical_feature_category ,0211 other engineering and technologies ,Process (computing) ,Geology ,Inversion (meteorology) ,02 engineering and technology ,Kinematics ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Signal ,Discrete element method ,Physics::Geophysics ,Rockfall ,Seismology ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Civil and Structural Engineering - Abstract
A rock avalanche that destroyed 23 houses and killed 35 people occurred on 28 August 2017, Nayong, SW China. Combined with the dynamic parameters from seismic signal inversion, a discrete element model, MatDEM was used to determine the rock avalanche’s kinematic behavior. Although the dynamic process obtained through inversion will be disturbed by factors, such as rockfall from the source area, by comparing the velocity of rock avalanche versus horizontal distance traveled, the best combination of parameters was selected from different values given. The dynamic process obtained by modeling was compared with the nearest seismometer frequency distribution spectrum, showing that the dynamic process is in good agreement with those parameters inverted from seismic signals. The simulation results show that the movement process lasted for nearly 40 s, with a maximum speed of 40 m/s. This model of selecting parameters contributes to explain the dynamic processes of similar rock avalanche more accurately and is of great significance to the hazard prediction in the karst area.
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- 2021
16. Network-Wide Forwarding Anomaly Detection and Localization in Software Defined Networks
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Chengchen Hu, Huanzhao Wang, Chao Shen, Shimin Xu, Zuoru Yang, Fangzheng Zhang, Peng Zhang, Hao Li, and Qi Li
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Computer Networks and Communications ,business.industry ,Network packet ,Computer science ,020206 networking & telecommunications ,02 engineering and technology ,Network topology ,Computer Science Applications ,Control theory ,Packet loss ,0202 electrical engineering, electronic engineering, information engineering ,Forwarding plane ,Overhead (computing) ,Anomaly detection ,Electrical and Electronic Engineering ,Routing control plane ,business ,Software-defined networking ,Software ,Computer network - Abstract
A crucial requirement for Software Defined Network (SDN) is that data plane forwarding behaviors should always agree with control plane policies. Such requirement cannot be met when there are forwarding anomalies , where packets deviate from the paths specified by the controller. Most anomaly detection methods for SDN install dedicated rules to collect statistics of each flow, and check whether the statistics conform to the “flow conservation principle”. We find these methods have a limited detection scope: they look at one flow each time, thus can only check a small number of flows simultaneously. In addition, dedicated rules for statistics collection can impose a large overhead on flow tables of SDN switches. To this end, this paper presents FOCES, a network-wide forwarding anomaly detection and localization method in SDN. Different from previous methods, FOCES applies a new kind of flow conservation principle at network wide, and can check forwarding behaviors of all flows in the network simultaneously, without installing any dedicated rules. Finally, FOCES applies a voting-based method to localize malicious switches when anomalies are detected. Experiments with four network topologies show that FOCES can achieve a detection precision higher than 90%, when the packet loss rate is no larger than 10%, and a localization accuracy of around 80% when the packet loss rate is no larger than 5%.
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- 2021
17. Counteraction of ABA-Mediated Inhibition of Seed Germination and Seedling Establishment by ABA Signaling Terminator in Arabidopsis
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Xia Li, Zhijuan Wang, Yang Zhao, Shimin Xu, Hongtao Zhao, Chunhong Cheng, Xinying Wu, Jingjing Lu, Tao Wang, Jian-Kang Zhu, Zhiping Deng, Hongtao Ji, Liu Liu, Mengmeng Cao, Liya Zhi, and Ziyin Ren
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0106 biological sciences ,0301 basic medicine ,Arabidopsis ,Germination ,Plant Science ,Biology ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Greening ,Gene Expression Regulation, Plant ,Molecular Biology ,Abscisic acid ,Pyr1 ,Arabidopsis Proteins ,organic chemicals ,fungi ,food and beverages ,Plants, Genetically Modified ,biology.organism_classification ,ABI1 ,Horticulture ,030104 developmental biology ,Terminator (genetics) ,chemistry ,Seedlings ,Seedling ,Seeds ,Abscisic Acid ,Signal Transduction ,010606 plant biology & botany - Abstract
Seed germination and seedling establishment are important for the reproductive success of plants, but seeds and seedlings typically encounter constantly changing environmental conditions. By inhibiting seed germination and post-germinative growth through the PYR1/PYL/RCAR ABA receptors and PP2C co-receptors, the phytohormone abscisic acid (ABA) prevents premature germination and seedling growth under unfavorable conditions. However, little is known about how the ABA-mediated inhibition of seed germination and seedling establishment is thwarted. Here, we report that ABA Signaling Terminator (ABT), a WD40 protein, efficiently switches off ABA signaling and is critical for seed germination and seedling establishment. ABT is induced by ABA in a PYR1/PYL/RCAR-PP2C-dependent manner. Overexpression of ABT promotes seed germination and seedling greening in the presence of ABA, whereas knockout of ABT has the opposite effect. We found that ABT interacts with the PYR1/PYL/RCAR and PP2C proteins, interferes with the interaction between PYR1/PYL4 and ABI1/ABI2, and hampers the inhibition of ABI1/ABI2 by ABA-bound PYR1/PYL4, thereby terminating ABA signaling. Taken together, our results reveal a core mechanism of ABA signaling termination that is critical for seed germination and seedling establishment in Arabidopsis.
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- 2020
18. Casting Defect and Process Optimization of Steel Crossing
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Dengyue Sun, Shimin Xu, Jiuming Xie, and Ruihao Lv
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Materials science ,Mechanics of Materials ,Mechanical Engineering ,Metallurgy ,Materials Chemistry ,Metals and Alloys ,Casting defect ,Process optimization - Published
- 2020
19. Investigation and dynamic analyses of rockslide-induced debris avalanche in Shuicheng, Guizhou, China
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Yanbo Zhang, Muhammad Bilal, Shimin Xu, Kaiping Jin, Aiguo Xing, Yu Zhuang, and Yaoqiang Zhu
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Hazard mapping ,021110 strategic, defence & security studies ,0211 other engineering and technologies ,Landslide ,02 engineering and technology ,Rockslide ,Geotechnical Engineering and Engineering Geology ,Field survey ,Debris ,Time history ,Natural hazard ,Arias Intensity ,Seismology ,Geology ,021101 geological & geomatics engineering - Abstract
On July 23, 2019, a large catastrophic landslide occurred in Shuicheng, Guizhou, China. It was a rapid and long run-out landslide that resulted in more than 50 casualties. The displaced materials traveled an approximate distance of 1250 m, with a descending height of around 465 m. In this paper, seismic record analyses and numerical simulation were conducted to determine the run-out behavior of the Shuicheng landslide. To determine the main characteristics of the landslide, geological and climatic settings were obtained by conducting a detailed field survey. The DAN3D model was used to simulate the propagation and run-out process of the landslide. It was observed that a combined Frictional-Voellmy model provides assuring results in simulating the Shuicheng landslide. The total duration of the landslide is 60 s with an average velocity of 20 m/s. The maximum velocity is estimated to be 40 m/s along the right bank of the valley, while a high initial velocity of 24 m/s was recorded at the initiation of the landslide. Seismic records obtained from the nearby seismic stations were used to calculate the location of the event and interpret the dynamic process of the landslide. The Arias intensity, Hilbert-Huang transform, and Empirical mode decomposition were used to obtain a detailed time history of the landslide. The results of the numerical simulation and seismic record analyses are expected to portray the process of similar landslides. This will improve the accuracy of landslide hazard mapping in the region.
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- 2020
20. LINC01116 regulates the proliferation and apoptosis of nucleus pulposus cells through miR-9-5p-mediated ZIC5 and the Wnt pathway and affects the progression of intervertebral disc degeneration
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Shimin Xu, Yuezhong Li, Junshan Zhang, and Zhiwei Li
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Medicine (miscellaneous) ,General Medicine - Abstract
Objective:: Intervertebral disc degeneration (IDD) represents one of the leading causes of low back pain. Research suggests the participation of LINC01116 in IDD progression. Herein, the current study explored the underlying mechanism of LINC01116 in IDD. Methods:: The differential expression patterns of LINC01116 in IDD and normal tissues were analyzed using the GEO database. Human nucleus pulposus (NP) cells were provided and treated with IL-1β to establish IDD models in vitro. LINC01116 expression was detected and intervened. Indices such as cell proliferation, apoptosis, and extracellular matrix (ECM)-related factor expression were determined using CCK-8 assay, flow cytometry, and Western blotting. LINC01116 sublocation was identified by means of nuclear/cytosol fractionation assay. The binding relationships between LINC01116 and miR-9-5p and miR-9-5p and ZIC5 were verified by bioinformatics analysis, dual-luciferase assays, RNA immunoprecipitation (RIP) assay, and RNA-pull-down. Western blotting was conducted to measure the levels of the Wnt pathway key factors. Results and Discussion:: LINC01116 was highly expressed in the degenerative NP cells. Silencing of LINC01116 critically promoted degenerative NP cell proliferation and inhibited apoptosis and ECM loss. LINC01116 was located in the cytoplasm. In degenerative NP cell models, LINC01116 could competitively bind to miR-9-5p to elevate ZIC5 expression. LINC01116 induced NP cell apoptosis and impeded NP cell proliferation and ECM synthesis by inhibiting miR-9-5p and miR-9-5p targeted ZIC5. ZIC5 could effectively increase the levels of the Wnt pathway-related factors. Conclusion:: Silencing LINC01116 blocked its adsorption of miR-9-5p as a sponge to promote the miR-9- 5p expression and inhibit ZIC5/Wnt activation, thus impacting NP cell biological functions
- Published
- 2022
21. MiR-98 Protects Nucleus Pulposus Cells against Apoptosis by Targeting TRAIL in Cervical Intervertebral Disc Degeneration
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Shimin Xu, Yuezhong Li, Junshan Zhang, Zhiwei Li, and Yanping Xing
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Lipopolysaccharides ,Medicine (General) ,Nucleus Pulposus ,Article Subject ,Biomedical Engineering ,Health Informatics ,Apoptosis ,Intervertebral Disc Degeneration ,MicroRNAs ,R5-920 ,Medical technology ,Humans ,Surgery ,R855-855.5 ,Biotechnology ,Research Article - Abstract
The excessive apoptosis of nucleus pulposus (NP) cells is a major risk factor in the progress of cervical intervertebral disc degeneration (IVDD). In this study, we investigated the impact of miR-98 on apoptosis of NP cells and the potential molecular mechanisms. Lipopolysaccharide (LPS) was used to establish an NP cell IVDD model. The sponging effect of miR-98 on TRAIL 3′UTR was predicted by ENCORI and assessed by the dual-luciferase reporter gene system. The expression levels of miR-98, TRAIL, and TRAIL pathway-related genes were tested by qRT-PCR, Western blot, and immunofluorescence analysis. Cell apoptosis was analyzed by Hoechst 33258 staining and flow cytometry. Cell viability was analyzed by MTT assay. It was found that the expression level of miR-98 was downregulated, while the level of TRAIL was upregulated in IVDD tissues, and their levels were negatively and positively associated with the clinical MRI grade, respectively. The LPS treatment resulted in a significant decrease of the miR-98 expression level and an increase of the TRAIL expression level in NP cells. miR-98 reduced NP cell apoptosis under LPS treatment in vitro. miR-98 directly targeted TRAIL. Moreover, the mRNA and protein levels of DR5, FADD, cleaved caspase8, cleaved caspase3, and cleaved PARP were downregulated by miR-98 overexpression. Overexpression of TRAIL partially reversed the suppressive roles of miR-98 on cell apoptosis and activation of the TRAIL pathway. We concluded that miR-98 inhibited apoptosis of NP cells by inactivating the TRAIL pathway via targeting TRAIL in IVDD NP cells. These results indicated that miR-98 might be a therapeutic target for IVDD.
- Published
- 2022
22. Peroxydisulfate production in situ by blue titania nanotube array electrode for tetracycline degradation in groundwater: Performance and mechanism
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Xuyang Hu, Ting Sun, Zhenyang Jing, Shimin Xu, Lihui Huang, and Zhenhui Gao
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General Chemical Engineering ,Electrochemistry ,Analytical Chemistry - Published
- 2022
23. Reduced blood circulating calcium level is an outstanding biomarker for preeclampsia among 48 types of human diseases
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Xianghong Li, Yixiong He, Juan Cong, Meng Zhang, Shimin Xu, Lijuan Zhang, and Yachong Guo
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medicine.medical_specialty ,Pulmonary disease ,chemistry.chemical_element ,Disease ,Calcium ,Gastroenterology ,Preeclampsia ,Sepsis ,Pulmonary Disease, Chronic Obstructive ,Blood circulating ,Pre-Eclampsia ,Pregnancy ,Internal medicine ,medicine ,Humans ,In patient ,business.industry ,General Medicine ,medicine.disease ,chemistry ,Case-Control Studies ,Biomarker (medicine) ,Female ,business ,Biomarkers - Abstract
Summary Background Calcium ion (Ca2+) is essential for human physiology by regulating various signal transduction pathways inside all cells and in the blood circulation. Aim We compared circulating Ca2+ levels in the healthy control against 48 different types of human diseases. Design A total of 144 201 independent test results of Ca2+ levels from 48 clinically defined diseases and 141 679 independent test results of Ca2+ from healthy individuals who came to the hospital for annual physical examination were retrieved during the past 5 years. Methods Ca2+ was determined by the standard ‘Arsenazo III method’ in the clinical laboratory of Affiliated Hospital of Qingdao University. We analyzed all data using RStudio V.1.3.1073 and python libraries 3.8. Results All 48 types of diseases had decreased Ca2+ levels than the healthy control based on either mean or median values. Patients suffering from preeclampsia had the lowest Ca2+ levels among all 48 diseases. The perfect area under the curve, sensitivity, and specificity values of 1.0, 0.96 and 0.96 indicated that Ca2+ was an excellent biomarker for diagnosing preeclampsia. Extremely low Ca2+ was present in patients suffering kidney-related diseases. Since the correlation between each disease on the statistical features is proportional to their vector distance, the two-component analysis revealed that preeclampsia, sepsis and chronic obstructive pulmonary disease were closely related among 48 diseases. Conclusions All human diseases were associated with reduced circulating Ca2+ levels, where the decreased Ca2+ was a perfect biomarker for preeclampsia. Kidney-related conditions were related to over-down-regulation of Ca2+ levels. The resemblance of preeclampsia to sepsis and chronic obstructive pulmonary disease based on two-component analysis suggested that the three unrelated diseases might share a similar mechanism of the circulating Ca2+ regulation.
- Published
- 2021
24. GmbZIP1 negatively regulates ABA-induced inhibition of nodulation by targeting GmENOD40–1 in soybean
- Author
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Xiaoxu Dong, Xinying Wu, Xuesong Wu, Jingjing Lu, Shimin Xu, Zhijuan Wang, Huifang Yuan, Jun Wu, Ziyin Ren, Shanshan Song, Xinyue Wang, and Xia Li
- Subjects
0106 biological sciences ,0301 basic medicine ,Drought tolerance ,Regulator ,Plant Development ,Plant Science ,Biology ,Nodulation ,01 natural sciences ,Marker gene ,Plant Root Nodulation ,03 medical and health sciences ,chemistry.chemical_compound ,Gene Expression Regulation, Plant ,lcsh:Botany ,Arabidopsis ,Abscisic acid ,Transcription factor ,organic chemicals ,fungi ,food and beverages ,biology.organism_classification ,Plants, Genetically Modified ,lcsh:QK1-989 ,Cell biology ,030104 developmental biology ,chemistry ,ABA ,Germination ,GmbZIP1 ,GmENOD40–1 ,Soybeans ,Signal transduction ,Soybean ,010606 plant biology & botany ,Research Article ,Abscisic Acid ,Rhizobium ,Signal Transduction ,Transcription Factors - Abstract
BackgroundAbscisic acid (ABA) plays an important role in plant growth and adaptation through the ABA signaling pathway. The ABA-responsive element binding (AREB/ABF) family transcriptional factors are central regulators that integrate ABA signaling with various signaling pathways. It has long been known that ABA inhibits rhizobial infection and nodule formation in legumes, but the underlying molecular mechanisms remain elusive.ResultsHere, we show that nodulation is very sensitive to ABA and exogenous ABA dramatically inhibits rhizobial infection and nodule formation in soybean. In addition, we proved that GmbZIP1, an AREB/ABF transcription factor, is a major regulator in both nodulation and plant response to ABA in soybean.GmbZIP1was specifically expressed during nodule formation and development. Overexpression ofGmbZIP1resulted in reduced rhizobial infection and decreased nodule number. Furthermore,GmbZIP1is responsive to ABA, and ectopic overexpression ofGmbZIP1increased sensitivity of Arabidopsis plants to ABA during seed germination and postgerminative growth, and conferred enhanced drought tolerance of plants. Remarkably, we found that GmbZIP1 directly binds to the promoter ofGmENOD40–1, a marker gene for nodule formation, to repress its expression.ConclusionOur results identified GmbZIP1 as a node regulator that integrates ABA signaling with nodulation signaling to negatively regulate nodule formation.
- Published
- 2021
25. Additional file 1 of GmbZIP1 negatively regulates ABA-induced inhibition of nodulation by targeting GmENOD40–1 in soybean
- Author
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Shimin Xu, Shanshan Song, Xiaoxu Dong, Xinyue Wang, Wu, Jun, Ziyin Ren, Xuesong Wu, Jingjing Lu, Huifang Yuan, Xinying Wu, Li, Xia, and Wang, Zhijuan
- Abstract
Additional file 1:. Supplementary information contains Supplementary Fig. S1-S3.
- Published
- 2021
- Full Text
- View/download PDF
26. Characteristic Analysis of the Nayong Rock Avalanche Based on the Seismic Signal
- Author
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Kaiping Jin, Yu Zhuang, Aiguo Xing, Hao Luo, and Shimin Xu
- Subjects
Hazard (logic) ,Seismometer ,Computer simulation ,Process (computing) ,Inversion (meteorology) ,Kinematics ,Signal ,Sw china ,Geology ,Seismology ,Physics::Geophysics - Abstract
A rock avalanche that destroyed 23 houses and killed 35 people occurred on 28 August 2017, Nayong, SW China. Combined with the dynamic parameters from seismic signal inversion, a discrete element model, MatDEM was used to determine the kinematic behaviour of the rock avalanche. By comparing the velocity evolution process of numerical simulation with that of seismic signal inversion, we are able to find the best fitting parameters. The dynamic process obtained by modelling was compared with the frequency distribution spectrum of the nearest seismometer, showing that the dynamic process is in good agreement with those parameters inverted from seismic signals. The simulation results show that the movement process lasted for nearly 40 s, with a maximum speed of 40 m/s. The selected models and parameters contribute to explain the dynamic processes of similar rock avalanche more accurately and are of considerable significance to the hazard prediction in karst area.
- Published
- 2020
27. Modeling of Intermesh Schedule for Strong Heavy Plate Roller Straightener and Finite Element Method Modification
- Author
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Meng Xu, Dengyue Sun, Shimin Xu, Peng Chen, and Hao Sun
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Regarding straightening unit as the research object, considered the different of roller spacing, a mathematical model of intermesh schedule suitable to the 2800 seven-roller strong heavy plate straightening machine was deduced by the geometric method. According to the mathematical model, the intermesh schedules of several specifications of plate were calculated, and the finite element model of straightening process was established in the finite element analysis software Abaqus. By analysing, it was found that those plates after straightening cannot meet the requirement of flatness, due to the existence of the work hardening. The bending deflection of the last straightening unit was modified and the new calculation formula of intermesh schedule was obtained. The values of the modified coefficients were determined by the finite element method. The intermesh schedules of other specifications of plate were calculated by the modified calculation formula and then verified it in Abaqus. The simulation results showed that those plates after straightening meet the requirement of flatness. So, the research results provide a theoretical basis for development of a new plate straightening machine and formulation of intermesh schedule.
- Published
- 2016
- Full Text
- View/download PDF
28. GAI Functions in the Plant Response to Dehydration Stress in
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Zhijuan, Wang, Liu, Liu, Chunhong, Cheng, Ziyin, Ren, Shimin, Xu, and Xia, Li
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Dehydration ,Arabidopsis Proteins ,Communication ,fungi ,GA ,ABF2 ,Arabidopsis ,food and beverages ,drought ,Droughts ,protein–protein interaction ,Gene Expression Regulation, Plant ,Stress, Physiological ,Protein Interaction Mapping ,Protein Interaction Maps ,DELLA - Abstract
DELLA (GAI/RGA/RGL1/RGL2/RGL3) proteins are key negative regulators in GA (gibberellin) signaling and are involved in regulating plant growth as a response to environmental stresses. It has been shown that the DELLA protein PROCERA (PRO) in tomato promotes drought tolerance, but its molecular mechanism remains unknown. Here, we showed that the gai-1 (gibberellin insensitive 1) mutant (generated from the gai-1 (Ler) allele (with a 17 amino acid deletion within the DELLA domain of GAI) by backcrossing gai-1 (Ler) with Col-0 three times), the gain-of-function mutant of GAI (GA INSENSITIVE) in Arabidopsis, increases drought tolerance. The stomatal density of the gai-1 mutant was increased but its stomatal aperture was decreased under abscisic acid (ABA) treatment conditions, suggesting that the drought tolerance of the gai-1 mutant is a complex trait. We further tested the interactions between DELLA proteins and ABF2 (abscisic acid (ABA)-responsive element (ABRE)-binding transcription factors) and found that there was a strong interaction between DELLA proteins and ABF2. Our results provide new insight into DELLA proteins and their role in drought stress tolerance.
- Published
- 2019
29. Application of zirconia thermal barrier coating on the surface of pulling-straightening roller
- Author
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Sun Dengyue, Feng Zhang, Huang Huagui, Haitao Hou, Shimin Xu, Jun Li, Jin Wu, and Jiuming Xie
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Fluid Flow and Transfer Processes ,Surface (mathematics) ,Thermal barrier coating ,020303 mechanical engineering & transports ,Materials science ,0203 mechanical engineering ,Mechanical Engineering ,Cubic zirconia ,02 engineering and technology ,Composite material ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Condensed Matter Physics - Published
- 2017
30. Discovery of novel N-1 substituted pyrazolopyrimidinones as potent, selective PDE2 inhibitors
- Author
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Pravien Abeywickrema, Shawn J. Stachel, Tamara D. Cabalu, Anthony T. Ginetti, Yili Chen, Daniel V. Paone, Michael P. Dwyer, Jonathan E. Wilson, Deping Wang, Alejandro Crespo, Jun Lu, Christopher Joseph Sinz, Gregori J. Morriello, and Shimin Xu
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Models, Molecular ,Steric effects ,Phosphodiesterase Inhibitors ,education ,Clinical Biochemistry ,Binding pocket ,Pharmaceutical Science ,Pyrimidinones ,Crystallography, X-Ray ,01 natural sciences ,Biochemistry ,Structure-Activity Relationship ,chemistry.chemical_compound ,Drug Discovery ,Humans ,Molecular Biology ,chemistry.chemical_classification ,Dose-Response Relationship, Drug ,Molecular Structure ,010405 organic chemistry ,Chemistry ,fungi ,Organic Chemistry ,Cyclic Nucleotide Phosphodiesterases, Type 2 ,Combinatorial chemistry ,0104 chemical sciences ,Amino acid ,010404 medicinal & biomolecular chemistry ,Pyrazoles ,Molecular Medicine ,Selectivity ,Lead compound - Abstract
A focused SAR study was conducted on a series of N1-substituted pyrazolopyrimidinone PDE2 inhibitors to reveal compounds with excellent potency and selectivity. The series was derived from previously identified internal leads and designed to enhance steric interactions with key amino acids in the PDE2 binding pocket. Compound 26 was identified as a lead compound with excellent PDE2 selectivity and good physicochemical properties.
- Published
- 2021
31. Characteristic analysis of the Nayong rock avalanche based on the seismic signal
- Author
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Aiguo Xing, Yueping Yin, Kaiping Jin, Hao Luo, Yu Zhuang, and Shimin Xu
- Subjects
Seismometer ,Computer simulation ,Process (computing) ,Inversion (meteorology) ,Kinematics ,Time series ,Signal ,Geology ,Discrete element method ,Seismology ,Physics::Geophysics - Abstract
A rock avalanche that destroyed 23 houses and killed 35 people occurred on August 28, 2017 in Nayong, southwest China. A discrete element model, MatDEM, was combined with the dynamic parameters of seismic signal inversion to determine the kinematic behavior of rock avalanches. The best fitting parameters were identified by comparing the velocity evolution process of numerical simulation with that of seismic signal inversion. The dynamic process obtained by modeling was compared with the frequency distribution spectrum of the nearest seismometer, with results revealing that the dynamic process agrees with the parameters inverted from the seismic signals. The simulation results further indicate that the movement process lasted for nearly 40 s, with a maximum speed of 40 m/s. The selected models and parameters can help provide a more accurate explanation of the dynamic processes of similar rock avalanches and are significant to hazard prediction in karst areas.
- Published
- 2020
32. FOCES: Detecting Forwarding Anomalies in Software Defined Networks
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Chengchen Hu, Huanzhao Wang, Peng Zhang, Zuoru Yang, Shimin Xu, Hao Li, and Qi Li
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021110 strategic, defence & security studies ,Network packet ,business.industry ,Computer science ,0211 other engineering and technologies ,020206 networking & telecommunications ,02 engineering and technology ,Network topology ,Packet loss ,0202 electrical engineering, electronic engineering, information engineering ,Forwarding plane ,Overhead (computing) ,Anomaly detection ,Routing control plane ,business ,Software-defined networking ,Computer network - Abstract
A crucial requirement for Software Defined Network (SDN) is that data plane forwarding behaviors should always agree with control plane policies. Such requirement cannot be met when there are forwarding anomalies, where packets deviate from the paths specified by the controller. Most anomaly detection methods for SDN install dedicated rules to collect statistics of each flow, and check whether the statistics conform to the flow conservation principle. Such per-flow detection methods have a limited detection scope: they look at one flow each time, thus can only check a limited number of flows simultaneously. In addition, dedicated rules for statistics collection can impose a large overhead on flow tables of SDN switches. To this end, this paper presents FOCES, a network-wide forwarding anomaly detection method in SDN. Different from previous methods, FOCES applies a new kind of flow conservation principle at network wide, and can check forwarding behaviors of all flows in the network simultaneously, without installing any dedicated rules. Experiments show FOCES can achieve a detection precision higher than 90% for four network topologies, even when packet loss rates are as high as 10%.
- Published
- 2018
33. Optimization of microwave-assisted extraction of wedelolactone from Eclipta alba using response surface methodology
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Dajing Shi, Shimin Xu, and Hui Ding
- Subjects
chemistry.chemical_compound ,Chromatography ,Materials science ,chemistry ,General Chemical Engineering ,Yield (chemistry) ,Extraction (chemistry) ,Ultrasonic assisted ,Eclipta alba ,Reflux extraction ,Response surface methodology ,Wedelolactone ,Microwave assisted - Abstract
An efficient microwave-assisted extraction technique was used to extract wedelolactone from Eclipta alba. To optimize the effects of the microwave-assisted extraction (MAE) processing parameters on the yield of wedelolactone, a response surface methodology with a central composite rotatable design was employed. Four independent variables were investigated: microwave power, ethanol concentration, extraction time and the solvent-to-solid ratio. The optimum conditions were: microwave power, 208W; ethanol concentration, 90%; extraction time, 26.5min; and solvent-tosolid ratio, 33mL·g−1. Under the optimal conditions, the extraction yield of wedelolactone was (82.67±0.16)%, which is in close agreement with the value predicted by the statistical model. MAE was also compared to other conventional methods, including ultrasonic assisted extraction, extraction at room temperature and heat reflux extraction. MAE has distinct advantages for the extraction of wedelolactone in terms of both time and efficiency. Therefore, MAE is a reliable method for the extraction of wedelolactone from Eclipta alba.
- Published
- 2014
34. Characteristics and runout behaviour of the disastrous 28 August 2017 rock avalanche in Nayong, Guizhou, China
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Gang Lv, Xingjian Dai, Aiguo Xing, Yaoqiang Zhu, Yu Zhuang, and Shimin Xu
- Subjects
geography ,geography.geographical_feature_category ,0211 other engineering and technologies ,Geology ,Landslide ,02 engineering and technology ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,Karst ,01 natural sciences ,Seismology ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
On 28th August 2017, a disastrous rock avalanche occurred in Nayong, Guizhou, China. This catastrophic event killed 35 people and destroyed 23 houses. In this study, the failure process of the avalanche was analyzed using UAV video footage and seismic signal recordings obtained for the pre- and post-failure stages of the landslide. To better understand the possible mechanism of the avalanche and its dynamic characteristics, a numerical simulation was conducted using a dynamic model (DAN3D) to simulate the runout behaviour of the displaced materials. Simulated results indicate that the failure process of the Nayong rock avalanche lasted approximately 30 s; the duration of the failure process is close to that from the UAV video footage and seismic signal recordings (35 s). The duration of movement during the landslide process is estimated to be approximately 90 s with a maximum velocity of 40 m/s. The combined frictional-Voellmy model delivered the most accurate results when simulating this event. The selected models and parameters are expected to aid in clarifying the propagation processes of similar rock avalanches and thus improve the accuracy of hazard prediction in mountainous karst areas.
- Published
- 2019
35. Silver carboxylate promoted lactonization: a general method applicable to prepare medium and large-sized lactones without high dilution or slow addition
- Author
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Le Liu, Hongwei Zhou, and Shimin Xu
- Subjects
Phoracantholide I ,chemistry.chemical_compound ,General method ,Chemistry ,Organic Chemistry ,Drug Discovery ,Carboxylate ,Biochemistry ,Combinatorial chemistry ,Task (project management) ,Dilution - Abstract
Efficient and applicable approach to macrolactonizations, with ready availability of starting materials and simple operation, remains a challenging task for the organic community. We developed a ‘freshman-can-do’ protocol to medium- and large-sized lactones, not depending on high-dilution or slow addition techniques. Application of this method for the synthesis of natural lactones or potentially pharmaceutical compounds might be useful for organic chemists and pharmacists.
- Published
- 2013
36. Isobaric vapor–liquid equilibrium for binary system of ethyl myristate + ethyl palmitate at 0.5, 1.0 and 1.5 kPa
- Author
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Hui Ding, Shimin Xu, Jun Hou, and Guiwen Tang
- Subjects
Activity coefficient ,Chemistry ,General Chemical Engineering ,General Physics and Astronomy ,Thermodynamics ,chemistry.chemical_compound ,Boiling point ,Non-random two-liquid model ,Vapor–liquid equilibrium ,Ethyl palmitate ,Isobaric process ,Binary system ,Physical and Theoretical Chemistry ,UNIFAC - Abstract
Isobaric vapor–liquid equilibrium (VLE) data for the system (ethyl myristate + ethyl palmitate) were measured at 0.5, 1.0 and 1.5 kPa with a VLE modified Othmer still. The esters used in this study are the major components of biodiesel. Thermodynamic consistency of the experimental data was checked both with the Herington consistency test and point consistency test of Van Ness Test, which ensure the reliability of experimental data. Furthermore, the experimental VLE data were regressed with Nonrandom Two-Liquid (NRTL) activity coefficient model and predicted by UNIFAC and Dortmund (modified UNIFAC) models. The results show that the calculated values of the vapor-phase mole fraction and boiling temperature by NRTL, UNIFAC models and Dortmund model agree well with the experimental data.
- Published
- 2013
37. Synthesis of Polyfunctionalized Quinolines via the Sequence of Propargyl–Allenyl Isomerization and Aza-electrocyclization
- Author
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Shimin Xu, Hongwei Zhou, and Le Liu
- Subjects
Aza Compounds ,Molecular Structure ,Organic Chemistry ,Quinoline ,Stereoisomerism ,Sequence (biology) ,Combinatorial chemistry ,Alkadienes ,chemistry.chemical_compound ,chemistry ,Cyclization ,Alkynes ,Propargyl ,Quinolines ,Molecule ,Isomerization - Abstract
Quinoline derivatives are important heterocyclic compounds because of their natural occurrence and applications in pharmaceutical fields. In this paper, a sequence of propargyl-allenyl isomerization and aza-electrocyclization for the synthesis of polyfunctionalized quinolines are described.
- Published
- 2012
38. Isobaric Vapor–Liquid Equilibrium of the Mixture of Methyl Palmitate and Methyl Stearate at 0.1 kPa, 1 kPa, 5 kPa, and 10 kPa
- Author
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Shimin Xu, Hui Ding, Jun Hou, and Tao Sun
- Subjects
Activity coefficient ,Methyl palmitate ,Chemistry ,General Chemical Engineering ,Non-random two-liquid model ,Vapor–liquid equilibrium ,Thermodynamics ,Isobaric process ,General Chemistry ,UNIFAC ,METHYL STEARATE ,Wilson model - Abstract
Isobaric vapor–liquid equilibrium (VLE) data of the mixture of methyl palmitate and methyl stearate at 0.1 kPa, 1 kPa, 5 kPa, and 10 kPa were measured with a modified Othmer still. Methyl palmitate and methyl stearate were the major components of the biodiesel. The experimental results were correlated with Wilson and nonrandom two-liquid (NRTL) activity coefficient models and were compared with a group contribution model (UNIFAC). The binary interaction parameters of the Wilson and NRTL models were fitted into the experimental data which were obtained at different pressures. The UNIFAC model did not predict the VLE for methyl palmitate and methyl stearate at reduced pressures well. The Wilson and NRTL models could well correlate with the experimental data at 1 kPa, 5 kPa, and 10 kPa. However, for the lower pressure 0.1 kPa, the Wilson model and NRTL model had worse correlatations with our experimental data than the higher pressures. These models could develop VLE calculations of the mixtures and provide g...
- Published
- 2012
39. Discovery of Highly Potent and Selective Pan-Aurora Kinase Inhibitors with Enhanced in Vivo Antitumor Therapeutic Index
- Author
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Sheena Quiambao, Ruwanthi N. Gunawardane, Dana Gitnick, Mindy I. Davis, Shawn R. Eichelberger, Mike A. Breider, Robert C. Armstrong, Gang Liu, Lan Tran, Michael F. Gardner, Michael J. Hadd, Julia M. Ford Pulido, Julius L. Apuy, Sunny Abraham, Barbara Belli, Joyce James, Helen Hua, Mark W. Holladay, Troy D. Vickers, Shimin Xu, and Daniel K. Treiber
- Subjects
Models, Molecular ,Transplantation, Heterologous ,Aurora inhibitor ,Antineoplastic Agents ,Protein Serine-Threonine Kinases ,Pharmacology ,Histones ,Rats, Sprague-Dawley ,Rats, Nude ,Structure-Activity Relationship ,Aurora kinase ,Therapeutic index ,Aurora Kinases ,In vivo ,Catalytic Domain ,Cell Line, Tumor ,Drug Discovery ,Animals ,Humans ,Phosphorylation ,Aurora Kinase A ,Cell Proliferation ,Triazines ,Cell growth ,Kinase ,Chemistry ,Stereoisomerism ,Rats ,Molecular Medicine ,Acetanilides ,Drug Screening Assays, Antitumor ,Neoplasm Transplantation ,Cytokinesis ,Protein Binding - Abstract
Serine/threonine protein kinases Aurora A, B, and C play essential roles in cell mitosis and cytokinesis. Currently a number of Aurora kinase inhibitors with different isoform selectivities are being evaluated in the clinic. Herein we report the discovery and characterization of 21c (AC014) and 21i (AC081), two structurally novel, potent, kinome-selective pan-Aurora inhibitors. In the human colon cancer cell line HCT-116, both compounds potently inhibit histone H3 phosphorylation and cell proliferation while inducing 8N polyploidy. Both compounds administered intravenously on intermittent schedules displayed potent and durable antitumor activity in a nude rat HCT-116 tumor xenograft model and exhibited good in vivo tolerability. Taken together, these data support further development of both 21c and 21i as potential therapeutic agents for the treatment of solid tumors and hematological malignancies.
- Published
- 2012
40. Synthesis of graphitic carbon nitride by directly heating sulfuric acid treated melamine for enhanced photocatalytic H2 production from water under visible light
- Author
-
Shimin Xu, Hongjian Yan, and Ye Chen
- Subjects
Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,Graphitic carbon nitride ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Sulfuric acid ,Condensed Matter Physics ,Sulfur ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,X-ray photoelectron spectroscopy ,Photocatalysis ,Melamine ,Carbon nitride ,BET theory - Abstract
Herein we report the synthesis of graphitic carbon nitride (g-C 3 N 4 ) by directly heating sulfuric acid treated melamine precursor. Thermoanalytical methods (TG-DSC) in combination with XRD, XPS and elemental analysis were used to characterize the condensation steps of the precursor. The TG-DSC curves clearly show significant difference in thermal behavior between the treated and untreated melamine. The sublimation of melamine during condensation was significantly suppressed by treating melamine with sulfuric acid. The decomposition of melamine sulfuric acid and the condensation of melamine occur simultaneously. The N/C ratio of the prepared carbon nitride (1.53) is slight higher than that of the ideal crystal g-C 3 N 4 (1.33), indicating the incomplete condensation of amino groups in the material. The XPS and elemental analysis show that there is no sulfur residue in the final product. The sample synthesized from sulfuric acid treated melamine shows relatively higher BET surface area. The photocatalytic performance of the as prepared carbon nitride was evaluated under visible light irradiation ( λ > 420 nm). The photocatalytic H 2 production rate on sample synthesized from sulfuric acid treated melamine is 2 times higher than that on sample synthesized from untreated melamine.
- Published
- 2012
41. STM studies of fusion of cholesterol suspensions and mixed 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/cholesterol vesicles onto a Au(111) electrode surface
- Author
-
Sek, Slawomir, Shimin Xu, Maohui Chen, Szymanski, Grzegorz, and Lipkowski, Jacek
- Subjects
Cholesterol -- Chemical properties ,Choline -- Chemical properties ,Dielectric films -- Structure ,Dielectric films -- Composition ,Thin films -- Structure ,Thin films -- Composition ,Chemistry - Abstract
The structure of the film fabricated by fusion of cholesterol suspension and mixed dimyristoylphosphatidylcholine (DMPC) is characterized and the effect of cholesterol on the mechanism of vesicle fusion at the Au(111) electrode surface is determined.
- Published
- 2008
42. Selecting the Optimum Predistillation Scheme for Heavy Crude Oils
- Author
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Yanjie Hou, Yanhong Wang, Hong Gao, Jinsheng Sun, and Shimin Xu
- Subjects
Exergy ,Work (thermodynamics) ,business.industry ,General Chemical Engineering ,General Chemistry ,Crude oil ,Industrial and Manufacturing Engineering ,law.invention ,law ,Scientific method ,Environmental science ,Process optimization ,Process engineering ,business ,Distillation - Abstract
The problem of designing a crude distillation unit (CDU) is not only a distillation design. It has the added complexity that the properties of crudes are different around the world, sometimes from heavy to light. In this work, we focused our attention on designing a predistillation scheme suitable for heavy crude oils by thermodynamic analysis. The exergy efficiencies and losses were analyzed to evaluate available schemes indicating that the two-preflash-drums case, with the highest exergy efficiencies, lowest exergy losses, and lowest furnace duty, is the best choice for heavy crude oils. In addition, the method of selecting the optimum process for energy saving may benefit the process optimization of other distillation units.
- Published
- 2011
43. Thionium ion promoted Michael acceptor: a sequence of Pummerer/Michael reactions for the stereoselective synthesis of 5-(1-(arylthio)vinyl)-oxazolines
- Author
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Shimin Xu, Hongwei Zhou, and Qianyun Zhang
- Subjects
Stereochemistry ,Chemistry ,Pummerer rearrangement ,Organic Chemistry ,Drug Discovery ,Michael reaction ,Stereoselectivity ,Biochemistry ,Sequence (medicine) ,Ion - Abstract
The synthesis of polysubstituted oxazolines is of great interest due to the synthetic and pharmaceutical importance. We developed a sequence of Pummerer/Michael reactions for the stereoselective synthesis of 5-(1-(arylthio)vinyl)-oxazolines.
- Published
- 2014
44. Physicochemical characteristics and anticoagulant activities of low molecular weight fractions by free-radical depolymerization of a fucosylated chondroitin sulphate from sea cucumber Thelenata ananas
- Author
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Jinhua Zhao, Hui Ding, Hui Kang, Shimin Xu, and Mingyi Wu
- Subjects
chemistry.chemical_classification ,Chromatography ,medicine.diagnostic_test ,biology ,Molecular mass ,Depolymerization ,Chemistry ,medicine.drug_class ,Low molecular weight heparin ,General Medicine ,Oligosaccharide ,biology.organism_classification ,Analytical Chemistry ,chemistry.chemical_compound ,Biochemistry ,medicine ,Thromboplastin ,Chondroitin sulfate ,Ananas ,Food Science ,Partial thromboplastin time - Abstract
A process of depolymerization of a new fucosylated chondroitin sulphate from Thelenata ananas by free-radicals was developed. The fractions with different molecular weights and a narrow molecular weight distribution was obtained. The products were characterised by physicochemical properties, FT-IR spectra and NMR spectra. The results confirm the retention of primary structure of the fractions after the depolymerization. Furthermore, the anticoagulant activity of the fractions was evaluated by the activated partial thromboplastin time (APTT). The APTT activity decreases in proportion to the molecular weight following a logarithmic-like function, and the potentiating of prolongation of APTT activity requires at least an oligosaccharide chain of about 6–8 units (6000–7000 Da). Compared to high doses of low molecular weight heparin (LMWH), a more desirable molecular weight fraction (13,950 Da) demonstrates significantly lower anticoagulant activity. Thus, the fraction has more potential as an antithrombotic agent with reduced bleeding risk relative to LMWH.
- Published
- 2010
45. Discovery and Evaluation of 7-Alkyl-1,5-bis-aryl-pyrazolopyridinones as Highly Potent, Selective, and Orally Efficacious Inhibitors of p38α Mitogen-Activated Protein Kinase⊥⊥ Atomic coordinates and structure factors for crystal structure of compound3dwith p38α can be accessed using PDB code 3LHJ
- Author
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Christiaan J. M. Saris, Lu Min Wong, Brad Herberich, Qiurong Liu, Bradley Henkle, Matthew R. Lee, Ryan Wurz, Liping H. Pettus, Christopher Mohr, Sharon X. Mu, Faye Hsieh, Matthew H. Plant, Samer Chmait, Helen J. McBride, Shimin Xu, Andrew Tasker, and Lisa Sherman
- Subjects
biology ,Kinase ,Chemistry ,Cyclin-dependent kinase 2 ,Pharmacology ,Protein kinase R ,Proinflammatory cytokine ,MAP2K7 ,Drug Discovery ,biology.protein ,Molecular Medicine ,ASK1 ,Tumor necrosis factor alpha ,MAPK14 - Abstract
The p38α mitogen-activated protein (MAP) kinase is a central signaling molecule in many proinflammatory pathways, regulating the cellular response to a multitude of external stimuli including heat, ultraviolet radiation, osmotic shock, and a variety of cytokines especially interleukin-1β and tumor necrosis factor α. Thus, inhibitors of this enzyme are postulated to have significant therapeutic potential for the treatment of rheumatoid arthritis, inflammatory bowel disease, and Crohn’s disease, as well as other diseases where aberrant cytokine signaling is the driver of disease. In this communication, we describe a novel class of 7-alkyl-1,5-bis-aryl-pyrazolopyridinone-based p38α inhibitors. In particular, compound 3f is highly potent in the enzyme and cell-based assays, selective in an Ambit kinase screen, and efficacious (ED50 ≤ 0.01 mg/kg) in the rat collagen induced arthritis (CIA) model.
- Published
- 2010
46. 3-Amino-7-phthalazinylbenzoisoxazoles as a Novel Class of Potent, Selective, and Orally Available Inhibitors of p38α Mitogen-Activated Protein Kinase
- Author
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David Powers, Guo-Qiang Cao, Scott Middleton, Lisa Sherman, Kelvin Sham, Dawei Zhang, Partha P. Chakrabarti, Faye Hsieh, Andrew Tasker, Yanyan Tudor, Bradley Henkle, Shimin Xu, Lu Min Wong, Ryan Wurz, Liping H. Pettus, Matthew R. Lee, Robert M. Rzasa, Violeta Yu, Christiaan J. M. Saris, Matthew H. Plant, and Rashid Syed
- Subjects
Models, Molecular ,MAPK/ERK pathway ,p38 mitogen-activated protein kinases ,Administration, Oral ,Arthritis ,Pharmacology ,Crystallography, X-Ray ,Proinflammatory cytokine ,Mitogen-Activated Protein Kinase 14 ,Structure-Activity Relationship ,Drug Discovery ,medicine ,Animals ,Humans ,Amines ,Protein kinase A ,Protein Kinase Inhibitors ,Molecular Structure ,biology ,Chemistry ,Benzene ,Isoxazoles ,medicine.disease ,Rats ,Disease Models, Animal ,Biochemistry ,Enzyme inhibitor ,Mitogen-activated protein kinase ,biology.protein ,Phthalazines ,Molecular Medicine ,Tumor necrosis factor alpha - Abstract
The p38 mitogen-activated protein kinase (MAPK) is a central signaling molecule in many proinflammatory pathways, regulating the cellular response to a multitude of external stimuli including heat, ultraviolet radiation, osmotic shock, and a variety of cytokines especially interleukin-1beta and tumor necrosis factor alpha. Thus, inhibitors of this enzyme are postulated to have significant therapeutic potential for the treatment of rheumatoid arthritis, inflammatory bowel disease, osteoporosis, and many other diseases where aberrant cytokine signaling is the driver of disease. Herein, we describe a novel class of 3-amino-7-phthalazinylbenzoisoxazole-based inhibitors. With relatively low molecular weight, these compounds are highly potent in enzyme and cell-based assays, with minimal protein shift in 50% human whole blood. Compound 3c was efficacious (ED 50 = 0.05 mg/kg) in the rat collagen induced arthritis (CIA) model.
- Published
- 2008
47. Design, Synthesis, and Biological Evaluation of Potent c-Met Inhibitors
- Author
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Douglas Hoffman, Andrew Tasker, Steven F. Bellon, Tae-Seong Kim, Randall W. Hungate, Chun Li, Yuan Cheng, Yihong Zhang, Angela Coxon, Celia Dominguez, Shimin Xu, Karen Rex, Longbin Liu, Elizabeth Rainbeau, Yaxiong Sun, Ning Xi, Teresa L. Burgess, Matthew R. Lee, Paul J. Reider, Yajing Yang, Aaron C. Siegmund, Ingrid M. Fellows, Noel D'angelo, Isabelle Dussault, Paula Kaplan-Lefko, and Shon Booker
- Subjects
Spectrometry, Mass, Electrospray Ionization ,Magnetic Resonance Spectroscopy ,C-Met ,Molecular Structure ,biology ,Drug discovery ,Drug Evaluation, Preclinical ,Proto-Oncogene Proteins c-met ,Crystallography, X-Ray ,In vitro ,Receptor tyrosine kinase ,Structure-Activity Relationship ,chemistry.chemical_compound ,chemistry ,Biochemistry ,Enzyme inhibitor ,In vivo ,Cell Line, Tumor ,Drug Discovery ,biology.protein ,Humans ,Molecular Medicine ,Structure–activity relationship ,Pyrimidone ,Protein Kinase Inhibitors - Abstract
c-Met is a receptor tyrosine kinase that plays a key role in several cellular processes but has also been found to be overexpressed and mutated in different human cancers. Consequently, targeting this enzyme has become an area of intense research in drug discovery. Our studies began with the design and synthesis of novel pyrimidone 7, which was found to be a potent c-Met inhibitor. Subsequent SAR studies identified 22 as a more potent analog, whereas an X-ray crystal structure of 7 bound to c-Met revealed an unexpected binding conformation. This latter finding led to the development of a new series that featured compounds that were more potent both in vitro and in vivo than 22 and also exhibited different binding conformations to c-Met. Novel c-Met inhibitors have been designed, developed, and found to be potent in vitro and in vivo.
- Published
- 2008
48. Application of a magnetotactic bacterium, Stenotrophomonas sp. to the removal of Au(III) from contaminated wastewater with a magnetic separator
- Author
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Xingang Li, Xu Han, Huiping Song, Jinsheng Sun, and Shimin Xu
- Subjects
Environmental Engineering ,Health, Toxicology and Mutagenesis ,Biomass ,Mechanics ,Absorption ,Microbiology ,Magnetics ,symbols.namesake ,chemistry.chemical_compound ,Adsorption ,Desorption ,Environmental Chemistry ,Sewage ,biology ,Public Health, Environmental and Occupational Health ,Biosorption ,Reproducibility of Results ,Water ,Langmuir adsorption model ,General Medicine ,General Chemistry ,Biodegradation ,biology.organism_classification ,Pollution ,Stenotrophomonas ,Biodegradation, Environmental ,Thiourea ,chemistry ,symbols ,Environmental Pollutants ,Gold ,Nuclear chemistry - Abstract
In this study, the feasibility of applying a magnetotactic bacterial isolate (MTB), Stenotrophomonas sp. to the removal of Au(III) was investigated. Biosorption experiments showed that Au(III) biosorption capacity exhibited no significant difference in the initial pH range of 1.0-5.5, while decreased more significantly in the initial pH range of 5.5-13.0. Langmuir isotherm indicated that the maximum Au(III) biosorption capacity of Stenotrophomonas sp. were 506, 369 and 308 mg g(-1) dry weight biomass at the initial pH values of 2.0, 7.0 and 12.0, respectively. Thiourea was proved to be an effective desorbent to recover Au from the MTB biomass and 91% Au adsorbed on the biomass could be recovered at equilibrium when the thiourea concentration was 0.8M. The magnetic separator developed by our research team used for separating Au loaded MTB biomass showed high separation efficiency, with 100% biomass removed at the magnetic intensity of 1200 Gs in 180 min. The analyses from FTIR and XRD further confirmed that the reduction of Au(III) to Au(0) by the reductants on the MTB biomass occurred, and the deposition of nano-crystal Au(0) particles, ranging from 24.7 to 31.4 nm, could be estimated on the biomass surface.
- Published
- 2008
49. Optimizing Conditions for the Purification of Linoleic Acid from Sunflower Oil by Urea Complex Fractionation
- Author
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Mingyi Wu, Song Wang, Shimin Xu, and Hui Ding
- Subjects
food.ingredient ,Chromatography ,General Chemical Engineering ,Sunflower oil ,Linoleic acid ,Organic Chemistry ,Fractionation ,law.invention ,chemistry.chemical_compound ,food ,Vegetable oil ,chemistry ,law ,Urea ,Organic chemistry ,Sunflower seed ,Process optimization ,Crystallization - Abstract
The separation and purification of linoleic acid (LA) from sunflower seed oil by urea complex fractionation was studied. Crystallization reaction conditions of urea inclusion were optimized using the response surface method, and the optimal model was developed. Using the linear weighting method of the fitting model for optimization, the optimal balance between the purity and the recovery of LA was obtained. Under optimal conditions, the purity of LA was 87.8%, and the recovery was 83.4% at a urea-to-fatty acids ratio (w/w) of 0.94, 95% ethanol-to-urea (v/w) of 5.00, a crystallization temperature of 18.0 °C, and a crystallization time of 5.0 h. Verification results revealed that the predicted values from these models were reasonably close to the experimentally observed values.
- Published
- 2008
50. Design and Operation of Batch Extractive Distillation with Two Reboilers
- Author
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Peng Bai, Xingang Li, Chao Hua, and Shimin Xu
- Subjects
Environmental Engineering ,Batch distillation ,business.industry ,Chemistry ,General Chemical Engineering ,Mode (statistics) ,General Chemistry ,Reboiler ,Biochemistry ,Operation mode ,Operation control ,Azeotropic distillation ,Scientific method ,Extractive distillation ,Process engineering ,business - Abstract
This paper proposes a modified operation mode of batch extractive distillation with two reboilers. The separation of ethanol and water using as ethylene glycol is well done to validate the feasibility of this mode. The pilot-plant experimental data under the identical operational conditions between the regular mode and the modified mode are in particular discussed. The studied results prove more practical advantages of the modified mode over the regular mode such as easier operation control, more flexibility and higher separation efficiency etc. So it supplies certain guidance for the industrial application of batch extractive distillation process.
- Published
- 2007
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