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Now showing items 1 - 16 of 57

  • An automatic short-answer grading model for semi-open-ended questions

    Zhang, Lishan   Huang, Yuwei   Yang, Xi   Yu, Shengquan   Zhuang, Fuzhen  

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  • Adaptively selecting biology questions generated from a semantic network

    Zhang, Lishan   VanLehn, Kurt  

    The paper describes a biology tutoring system with adaptive question selection. Questions were selected for presentation to the student based on their utilities, which were estimated from the chance that the student's competence would increase if the questions were asked. Competence was represented by the probability of mastery of a set of biology knowledge components. Tasks were represented and selected based on which knowledge components they addressed. Unlike earlier work, where the knowledge components and their relationships to the questions were defined by domain experts, this project demonstrated that the knowledge components, questions and their relationships could all be generated from a semantic network. An experiment found that students using our adaptive question selection had reliably largerlearning gains than students who received questions in a mal-adaptive order.
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  • Electrospinning of PAN/Ag NPs nanofiber membrane with antibacterial properties

    Wang, Chenrong   Wang, Wei   Zhang, Lishan   Zhong, Shan   Yu, Dan  

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  • Theoretical and experimental study of scour depth by submerged water jet

    Hou, Jiaoyi   Zhang, Lishan   Gong, Yongjun   Ning, Dayong   Zhang, Zengmeng  

    The characteristics and working principles of the impinging by submerged water jet are analyzed, and the relevant mathematical model is optimized based on Rajaratnam's theoretical and experimental study. A new mathematical model is constructed by adding an important parameter called impinging angle. A new experiment is designed according to the working conditions of various impinging distances and angles. In combination with the experiment data and with the use of the curve fitting method, the functional relationship between the impinging distance and angle as well as the coefficient C-4 is obtained. The experiment results show that the scour depth decreases as impinging distance increases, followed by a trend from decline to rise before falling again; those two turning points occur within the range of 20d-25d. The scour depth constantly increases with rising impinging angle, and the maximum and minimum increasing ranges can reach 180% and 50%, respectively, with the impinging angle increasing from 40 degrees to 90 degrees
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  • How do machine-generated questions compare to human-generated questions?

    Zhang, Lishan   VanLehn, Kurt  

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  • Adaptively selecting biology questions generated from a semantic network

    Zhang, Lishan   VanLehn, Kurt  

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  • Atmospheric Pollution Monitoring in Urban Area by Employing a 450-nm Lidar System

    Kong, Zheng   Liu, Zhi   Zhang, Lishan   Guan, Peng   Li, Limei   Mei, Liang  

    In past decades, lidar techniques have become main tools for atmospheric remote sensing. However, traditional pulsed lidar systems are relatively expensive and require considerable maintenance. These shortcomings may be overcome by the development of a blue band Scheimpflug lidar system in Dalian, Northern China. Atmospheric remote measurements were carried out for 10 days in an urban area to validate the feasibility and performance of a 450-nm Scheimpflug lidar system. A 24-h continuous measurement was achieved in winter on a near horizontal path with an elevation angle of about 6.4 degrees. The aerosol extinction coefficient retrieved by the Fernald-inversion algorithm shows good agreement with the variation of PM10/PM2.5 concentrations recorded by a national pollution monitoring station. The experimental result reveals that the linear ratio between the aerosol extinction coefficient and the PM10 concentration under high relative humidity (75-90%) is about two-times that in low relative humidity (75%) when the PM10 concentrations are less than 100 mu g/m(3).
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  • The Neuron-Specific Protein TMEM59L Mediates Oxidative Stress-Induced Cell Death

    Zheng, Qiuyang   Zheng, Xiaoyuan   Zhang, Lishan   Luo, Hong   Qian, Lingzhi   Fu, Xing   Liu, Yiqian   Gao, Yuehong   Niu, Mengxi   Meng, Jian   Zhang, Muxian   Bu, Guojun   Xu, Huaxi   Zhang, Yun-wu  

    TMEM59L is a newly identified brain-specific membrane-anchored protein with unknown functions. Herein we found that both TMEM59L and its homolog, TMEM59, are localized in Golgi and endosomes. However, in contrast to a ubiquitous and relatively stable temporal expression of TMEM59, TMEM59L expression was limited in neurons and increased during development. We also found that both TMEM59L and TMEM59 interacted with ATG5 and ATG16L1, and that overexpression of them triggered cell autophagy. However, overexpression of TMEM59L induced intrinsic caspase-dependent apoptosis more dramatically than TMEM59. In addition, downregulation of TMEM59L prevented neuronal cell death and caspase-3 activation caused by hydrogen peroxide insults and reduced the lipidation of LC3B. Finally, we found that AAV-mediated knockdown of TMEM59L in mice significantly ameliorated caspase-3 activation, increased mouse duration in the open arm during elevated plus maze test, reduced mouse immobility time during forced swim test, and enhanced mouse memory during Ymaze and Morris water maze tests. Together, our study indicates that TMEM59L is a pro-apoptotic neuronal protein involved in animal behaviors such as anxiety, depression, and memory, and that TMEM59L downregulation protects neurons against oxidative stress.
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  • The climatic characteristics and formation mechanism of acid rain in Guilin,China

    Zhong, Shan   Wei, Zengxian   Zhang, Lishan   Li, Yongshan   Du, Juan  

    A comprehensive study on climatic conditions and the chemical compositions of the rainwater had been undertaken from 2011 to 2015. Over 200 samples were taken and analyzed for pH in each year. Particularly, 240 samples taken in 2015 were analyzed for major ions. The results showed that the average frequency of acid rain in Guilin City was as high as 60% from 2011 to 2015. The order of the anion and cation concentration in precipitation was S042->NO3>C1->F-, Ca2 >NH4 >K >Na >Mg2+, respectively. Ca2+ plays an important catalytic role on the photochemical conversion process of S042-. The formation of a large number of sulfates led to the occurrence of acid rain in Guilin. The adverse meteorological conditions in the winter and spring season were found to be a main reason for most serious acid rain pollution episodes during this period.
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  • Evaluation of a meta-tutor for constructing models of dynamic systems

    Zhang, Lishan   VanLehn, Kurt   Girard, Sylvie   Burleson, Winslow   Chavez-Echeagaray, Maria Elena   Gonzalez-Sanchez, Javier   Hidalgo-Pontet, Yoalli  

    Modelling is an important skill to acquire, but it is not an easy one for students to learn. Existing instructional technology has had limited success in teaching modelling. We have applied a recently developed technology, meta-tutoring, to address the important problem of teaching model construction. More specifically, we have developed and evaluated a system that has two parts, a tutor and a meta-tutor. The tutor is a simple step-based tutoring system that can give correct/incorrect feedback on student's steps and can demonstrate steps for students when asked. Because deep modelling requires difficult analyses of the quantitative relationships in a given system, we expected, and found, that students tended to avoid deep modelling by abusing the tutor's help. In order to increase the frequency of deep modelling, we added a meta-tutor that coached students to follow a learning strategy that decomposed the overall modelling problem into a series of "atomic" modelling problems. We conducted three experiments to test the effectiveness of the meta-tutor. The results indicate that students who studied with meta-tutor did indeed engage in more deep modelling practices. However, when the meta-tutor and tutor were turned off, students tended to revert to shallow modelling. Thus, the next stage of the research is to add an affective agent that will try to persuade students to persist in using the taught strategies even when the meta-tutoring and tutoring have ceased. (C) 2014 Elsevier Ltd. All rights reserved.
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  • 25-Hydroxycholesterol promotes migration and invasion of lung adenocarcinoma cells

    Chen, Li   Zhang, Lishan   Xian, Guozhe   Lv, Yinping   Lin, Yanliang   Wang, Yibing  

    25-hydroxycholesterol (25-HC) is enzymatically produced by cholesterol 25-hydorxylase in various organs and is involved in many processes, including lipid metabolism, inflammation and the immune response. However, the role of 25-HC in the migration and invasion of lung adenocarcinoma (ADC) cells remains largely unknown. In this study, we demonstrated that 0.1 mu M 25-HC promoted ADC cell migration and invasion without affecting cell proliferation, especially after coculture with THP1-derived macrophages. Further investigation showed that 0.1 mu M 25-HC significantly stimulated interleukin-1 beta (IL-1 beta) secretion in a coculture system and increased the expression of LXR and Snail. IL-1 beta also mimicked the effect of 25-HC. LXR knockdown notably blocked the 25-HC-induced Snail expression, migration and invasion in both the monoculture system and the coculture system, but it did not impact the effect of IL-1 beta, which suggested that IL-1 beta functioned in an LXR-independent manner. These results suggested that 25-HC promoted ADC cell migration and invasion in an LXR-dependent manner in the monoculture system but that in the coculture system, the 25-HC-induced IL-1 beta secretion enhanced the effect of 25-HC in an LXR-independent manner. (C) 2017 Elsevier Inc. All rights reserved.
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  • The climatic characteristics and formation mechanism of acid rain in Guilin, China

    Zhong, Shan   Wei, Zengxian   Zhang, Lishan   Li, Yongshan   Du, Juan  

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  • Precise chronology of differentiation of developing human primary dentition.

    Hu, Xuefeng   Xu, Shan   Lin, Chensheng   Zhang, Lishan   Chen, YiPing   Zhang, Yanding  

    While correlation of developmental stage with embryonic age of the human primary dentition has been well documented, the available information regarding the differentiation timing of the primary teeth was largely based on the observation of initial mineralization and varies significantly. In this study, we aimed to document precise differentiation timing of the developing human primary dentition. We systematically examined the expression of odontogenic differentiation markers along with the formation of mineralized tissue in each developing maxillary and mandibular teeth from human embryos with well-defined embryonic age. We show that, despite that all primary teeth initiate development at the same time, odontogenic differentiation begins in the maxillary incisors at the 15th week and in the mandibular incisors at the 16th week of gestation, followed by the canine, the first primary premolar, and the second primary premolar at a week interval sequentially. Despite that the mandibular primary incisors erupt earlier than the maxillary incisors, this distal to proximal sequential differentiation of the human primary dentition coincides in general with the sequence of tooth eruption. Our results provide an accurate chronology of odontogenic differentiation of the developing human primary dentition, which could be used as reference for future studies of human tooth development. =20
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  • Antioxidant Ability and Mechanism of Rhizoma Atractylodes macrocephala

    Li, Xican   Lin, Jian   Han, Weijuan   Mai, Wenqiong   Wang, Li   Li, Qiang   Lin, Miaofang   Bai, Mingsong   Zhang, Lishan   Chen, Dongfeng  

    Rhizoma Atractylodes macrocephala (AM) has been used in Traditional Chinese Medicine (TCM) for about 2,000 years. In the study, we firstly determined the antioxidant levels of five AM extracts by center dot OH-scavenging, center dot O-2(-)-scavenging, Fe2+-chelating, Cu2+-chelating, DPPH center dot-scavenging, and ABTS(+)center dot-scavenging assays. After measurement of the chemical contents in five AM extracts, we quantitatively analyzed the correlations between antioxidant levels and chemical contents. It was observed that total phenolics and total flavonoids had significant positive correlations with antioxidant levels (R = 0.685 and 0.479, respectively). In contrast, total sugars and total saponins presented lower correlations with antioxidant levels (R = -0.272 and 0.244, respectively). It means that antioxidant activity of AM should be attributed to total phenolics (including phenolic acids and flavonoids), and not total sugars and total saponins. Further analysis indicated that phenolic acids exhibited higher R values with radical-scavenging assays (R = 0.32-1.00), while flavonoids showed higher R values with metal-chelating assays (R = 0.86 and 0.90). In conclusion, AM exerts its antioxidant effect through metal-chelating, and radical-scavenging which is via donating hydrogen atom and donating electron. Its metal-chelating may result from flavonoids, while its radical-scavenging can be attributed to phenolic acids, especially caffeic acid, ferulic acid, and protocatechuic acid.
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  • Distal Finger Reconstruction by Bilateral Lateral Hallux Osteo-onychocutaneous Free Flap

    Wang, Zengtao   Sun, Wenhai   Lineaweaver, William C.   Hao, Liwen   Qiu, Shenqiang   Zhang, Lishan   Chen, Chao   Chiu, Yung-Cheng   Yilihamu, Yilizati   Zhang, Feng  

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  • 27-Hydroxycholesterol enhanced osteoclastogenesis in lung adenocarcinoma microenvironment

    Zhang, Lishan   Liu, Ming   Liu, Jinglei   Li, Xingkai   Yang, Ming   Su, Benhua   Lin, Yanliang  

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