Teacher Agency: A Two-level Ecological Model

CHANG-YOU ZHANG,Jocelyn Wright 21세기영어영문학회 2017 영어영문학21 Vol.30 No.4

Despite the rich literature on agency in sociological studies, systematic conceptualizations of teacher agency (TA) are relatively new. Moreover, ecologically-inspired approaches to this construct have emerged only recently. In response to this situation, in this paper, we briefly review the theoretical background of agency and develop a more ecologically-oriented and holistic model of TA. To arrive at this, we first introduce the ecological perspective, followed by descriptions of four key concepts relevant to our study. We then offer an analysis of one recent framework of TA, devised by Priestley, Biesta, and Robinson (2015), which appears to be the first one that approaches TA from an ecological perspective. In acknowledging the values and contributions of this framework, we also locate a number of areas that justify our proposal of a new model. By integrating van Lier's (2004a) ecological diagram of affordance in context into the existing framework, our revised model elaborates and extends the previous one making it more explicitly ecological. In so doing, we recognize TA as an emergent phenomenon, as a result of the complex interactions at two levels. This ecologically-extended conceptualization of TA is expected to open up space for more context-sensitive and ecologically-valid research on agency in general, and TA in particular.

An OSSE Study for Deep Argo Array using the GFDL Ensemble Coupled Data Assimilation System

Chang, You-Soon,Zhang, Shaoqing,Rosati, Anthony,Vecchi, Gabriel A.,Yang, Xiaosong Korean Ocean Research & Development Institute and 2018 OCEAN SCIENCE JOURNAL Vol.53 No.2

An observing system simulation experiment (OSSE) using an ensemble coupled data assimilation system was designed to investigate the impact of deep ocean Argo profile assimilation in a biased numerical climate system. Based on the modern Argo observational array and an artificial extension to full depth, 'observations' drawn from one coupled general circulation model (CM2.0) were assimilated into another model (CM2.1). Our results showed that coupled data assimilation with simultaneous atmospheric and oceanic constraints plays a significant role in preventing deep ocean drift. However, the extension of the Argo array to full depth did not significantly improve the quality of the oceanic climate estimation within the bias magnitude in the twin experiment. Even in the 'identical' twin experiment for the deep Argo array from the same model (CM2.1) with the assimilation model, no significant changes were shown in the deep ocean, such as in the Atlantic meridional overturning circulation and the Antarctic bottom water cell. The small ensemble spread and corresponding weak constraints by the deep Argo profiles with medium spatial and temporal resolution may explain why the deep Argo profiles did not improve the deep ocean features in the assimilation system. Additional studies using different assimilation methods with improved spatial and temporal resolution of the deep Argo array are necessary in order to more thoroughly understand the impact of the deep Argo array on the assimilation system.

Effects of different biochar amendments on carbon loss and leachate characterization from an agricultural soil

Yang, Xing Ya,Chang, Kwang-Hyeon,Kim, You Jin,Zhang, Jin,Yoo, Gayoung Elsevier 2019 CHEMOSPHERE - Vol.226 No.-

<P><B>Abstract</B></P> <P>Selection of an appropriate biochar as a soil amendment requires a thorough investigation of the effects on soil ecosystems and adjacent water systems via leaching. Different biochar characteristics influence retention or leaching of different soil and biochar components. A lab lysimeter study was conducted to investigate carbon (C) balance and leachate quality with biochar additions. Biochar made from wood pellets (WP) and sewage sludge (SS) produced at 400 °C (WP400 and SS400) and 700 °C (WP700 and SS700), respectively, were applied to silt loam soil at an application rate of 4%. Fluorescence excitation-emission spectrophotometry (EEMs) was utilized to understand the compositional changes in leachate dissolved organic carbon (DOC). Our results show that DOC contributed the largest portion of C leaching loss. The WP treatments increased DOC mass loss, but did not significantly change leachate DOC quality. SS400, in comparison, increased mass loss of DOC and SS700 decreased it probably due to its higher adsorptive capacity to DOC. Unlike WP treatments, SS treatments significantly changed leachate DOC quality. Chemical oxygen demand (COD) was reduced with SS400 and SS700 biochar additions, which is assumed to be related to SS biochar's high oxygen-containing surface functional groups. Reduction in total nitrogen (TN) leaching by WP700 and SS700 treatments might be related to the higher micropore surface area. Over all, our findings imply that changes in the different components of the leachate from biochar-amended soil are related to different biochar properties, such as labile matter content, total surface area, micropore volume and cation exchange capacity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> DOC contributed the largest portion of C leaching loss from biochar added soils. </LI> <LI> Leachate properties of biochar addition were related to biochar characteristics. </LI> <LI> Wood pellet biochar increased DOC leaching but did not influence DOC quality. </LI> <LI> Sewage sludge biochar (700 °C) reduced COD/TN leaching and retained humic substances. </LI> </UL> </P>

Effects of the Physical and the Chemical Characters of Soil on Ginseng Quality and Yield

Chang, Wei-Chun,Zha, Libo,Cao, Xiuying,Zhang, Lianxue,Kong, Xiangyi,Zhao, Shoujing,You, Wei The Korean Society of Ginseng 1992 Journal of Ginseng Research Vol.16 No.3

THE COMPUTER COMMUNICATION WITH SPECIAL MICROPROCESSOR

Zhang Shu Fang,Xu Chang Yu,Li Ding You 대한전자공학회 1992 대한전자공학회 Conference Vol.1992 No.2

Polystyrene-b-poly(oligo(ethylene oxide) Monomethyl Ether Methacrylate)-b-polystyrene Triblock Copolymers as Potential Carriers for Hydrophobic Drugs

You, Qianqian,Chang, Haibo,Guo, Qipeng,Zhang, Yudong,Zhang, Puyu Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.2

A simple and effective method is introduced to synthesize a series of polystyrene-b-poly(oligo(ethylene oxide) monomethyl ether methacrylate)-b-polystyrene (PSt-b-POEOMA-b-PSt) triblock copolymers. The structures of PSt-b-POEOMA-b-PSt copolymers were characterized by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance ($^1H$ NMR) spectroscopy. The molecular weight and molecular weight distribution of the copolymer were measured by gel permeation chromatography (GPC). Furthermore, the self-assembling and drug-loaded behaviours of three different ratios of PSt-b-POEOMA-b-PSt were studied. These copolymers could readily self-assemble into micelles in aqueous solution. The vitamin E-loaded copolymer micelles were produced by the dialysis method. The micelle size and core-shell structure of the block copolymer micelles and the drug-loaded micelles were confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The thermal properties of the copolymer micelles before and after drug-loaded were investigated by different scanning calorimetry (DSC). The results show that the micelle size is slightly increased with increasing the content of hydrophobic segments and the micelles are still core-shell spherical structures after drug-loaded. Moreover, the glass transition temperature (Tg) of polystyrene is reduced after the drug loaded. The drug loading content (DLC) of the copolymer micelles is 70%-80% by ultraviolet (UV) photolithography analysis. These properties indicate the micelles self-assembled from PSt-b-POEOMA-b-PSt copolymers would have potential as carriers for the encapsulation of hydrophobic drugs.

심포지움 초록 - Ⅰ ( 국제인삼심포지움 , 1992년 8월 10-14 , 장춘 , 중국 ) ( Abstracts - Ⅰ ( '92 International Ginseng Symposium , August 10-14 , 1992 , Changchun , China )

Chang Weichun,Zhao Libe,Cao Xiuying,Zhang Lianxue,Kong Xiangyi,Zhao Shoujing,You Wei 고려인삼학회 1992 Journal of Ginseng Research Vol.16 No.3

Endovascular Treatment of Traumatic Pseudoaneurysm Presenting as Intractable Epistaxis

Chang wei Zhang,Xiao dong Xie,Chao You,Bo yong Mao,Chao hua Wang,Min He,Hong Sun 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.6

Objective: To investigate the clinical efficacy of individual endovascular management for the treatment of different traumatic pseudoaneurysms presenting as intractable epistaxis. Materials and Methods: For 14 consecutive patients with traumatic pseudoaneurysm presenting as refractory epistaxes, 15 endovascular procedures were performed. Digital subtraction angiography revealed that the pseudoaneurysms originated from the internal maxillary artery in eight patients; and all were treated with occlusion of the feeding artery. In six cases, they originated from the internal carotid artery (ICA); out of which, two were managed with detachable balloons, two with covered stents, one by means of cavity embolization, and the remaining one with parent artery occlusion. All of these cases were followed up clinically from six to 18 months, with a mean follow up time of ten months; moreover, three cases were also followed with angiography. Results: Complete cessation of bleeding was achieved in all the 15 instances (100%) immediately after the endovascular therapies. Of the six patients who suffered from ICA pseudoaneurysms, one presented with a permanent stroke and one had an episode of rebleeding requiring intervention. Conclusion: In patients presenting with a history of craniocerebral trauma, traumatic pseudoaneurysm must be considered as a differential diagnosis. Individual endovascular treatment is a relatively safe, plausible, and reliable means of managing traumatic pseudoaneurysms. Objective: To investigate the clinical efficacy of individual endovascular management for the treatment of different traumatic pseudoaneurysms presenting as intractable epistaxis. Materials and Methods: For 14 consecutive patients with traumatic pseudoaneurysm presenting as refractory epistaxes, 15 endovascular procedures were performed. Digital subtraction angiography revealed that the pseudoaneurysms originated from the internal maxillary artery in eight patients; and all were treated with occlusion of the feeding artery. In six cases, they originated from the internal carotid artery (ICA); out of which, two were managed with detachable balloons, two with covered stents, one by means of cavity embolization, and the remaining one with parent artery occlusion. All of these cases were followed up clinically from six to 18 months, with a mean follow up time of ten months; moreover, three cases were also followed with angiography. Results: Complete cessation of bleeding was achieved in all the 15 instances (100%) immediately after the endovascular therapies. Of the six patients who suffered from ICA pseudoaneurysms, one presented with a permanent stroke and one had an episode of rebleeding requiring intervention. Conclusion: In patients presenting with a history of craniocerebral trauma, traumatic pseudoaneurysm must be considered as a differential diagnosis. Individual endovascular treatment is a relatively safe, plausible, and reliable means of managing traumatic pseudoaneurysms.

Preventive Effect of 7,8-Dihydroxyflavone against Oxidative Stress Induced Genotoxicity

Zhang, Rui,Kang, Kyoung Ah,Piao, Mei Jing,Ko, Dong Ok,Wang, Zhi Hong,Chang, Weon Young,You, Ho Jin,Lee, In Kyung,Kim, Bum Joon,Kang, Sam Sik,Hyun, Jin Won Pharmaceutical Society of Japan 2009 Biological & pharmaceutical bulletin Vol.32 No.2

<P>We elucidated the protective effect of 7,8-dihydroxyflavone against hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>)-induced DNA damage. We found that 7,8-dihydroxyflavone scavenges 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and intracellular reactive oxygen species (ROS). 7,8-Dihydroxyflavone with antioxidant effect prevented the H<SUB>2</SUB>O<SUB>2</SUB>-induced cellular DNA damage, as evidenced by comet tail, 8-hydroxy-2′-deoxyguanosine (8-OHdG) content, and phospho-histone H2A.X protein expression. Hence, 7,8-dihydroxyflavone was shown to protect cell <I>via</I> the inhibition of apoptosis induced by H<SUB>2</SUB>O<SUB>2</SUB>. This was substantiated by decreased apoptotic nuclear fragmentation, decreased sub-G<SUB>1</SUB> cell population, and decreased DNA fragmentation. Furthermore, 7,8-dihydroxyflavone activated the protein kinase B (PKB, Akt) signal pathway, which is a major survival signal pathway. In addition, LY294002, which is phosphatidylinositol 3 kinase (PI3K, upstream of Akt) inhibitor, attenuated the protective effect of 7,8-dihydroxyflavone against H<SUB>2</SUB>O<SUB>2</SUB>-induced cell damage. In conclusion, 7,8-dihydroxyflavone was shown to possess cytoprotective properties against oxidative stress by scavenging intracellular ROS and enhancing Akt activity.</P>

Post-Transcriptional Control of Tropoelastin in Aortic Smooth Muscle Cells Affects Aortic Dissection Onset

You-Fei Qi,Chang Shu,Zhan-Xiang Xiao,Ming-Yao Luo,Kun Fang,Yuan-Yuan Guo,Wen-Bo Zhang,Jie Yue 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.3

Aortic dissection (AD) is a catastrophic disease with high mortality and morbidity, characterized with fragmentation of elastin and loss of smooth muscle cells. Although AD has been largely attributable to polymorphisms defect in the elastin-coding gene, tropoelastin (TE), other undermined factors also appear to play roles in AD onset. Here, we investigated the effects of post-transcriptional control of TE by microRNAs (miRNAs) on elastin levels in aortic smooth muscle cells (ASMC). We found that miR-144-3p is a miRNA that targets TE mRNA in both human and mouse. Bioinformatics analyses and dual luciferase reporter assay showed that miR-144-3p inhibited protein translation of TE, through binding to the 3-UTR of the TE mRNA. Interestingly, higher miR-144-3p levels and lower TE were detected in the ASMC obtained from AD patients, compared to those from non-AD controls. In a mouse model for human AD, infusion of adeno-associated viruses (serotype 6) carrying antisense for miR-144-3p (as-miR-144-3p) under CAG promoter significantly reduced the incidence and severity of AD, seemingly through enhancement of TE levels in ASMC. Thus, our data suggest an essential role of miR-144-3p on the pathogenesis of AD.