W. Xing - Academia.edu (original) (raw)

Papers by W. Xing

ABSTRACT This study proposes a process-oriented, automatic, formative assessment model for small ... more ABSTRACT This study proposes a process-oriented, automatic, formative assessment model for small group learning based on complex systems theory using a small dataset from a technology-mediated, synchronous mathematics learning environment. We first conceptualize small group learning as a complex system and explain how group dynamics and interaction can be modeled via theoretically grounded, simple rules. These rules are then operationalized to build temporally-embodied measures, where varying weights are assigned to the same measures according to their significance during different time stages based on the golden ratio concept. This theory-based measure construction method in combination with a correlation-based feature subset selection algorithm reduces data dimensionality, making a complex system more understandable for people. Further, because the discipline of education often generates small datasets, a Tree-Augmented Naive Bayes classifier was coded to develop an assessment model, which achieves the highest accuracy (95.8%) as compared to baseline models. Finally, we describe a web-based tool that visualizes time-series activities, assesses small group learning automatically, and also offers actionable intelligence for teachers to provide real-time support and intervention to students. The fundamental contribution of this paper is that it makes complex, small group behavior visible to teachers in a learning context quickly. Theoretical and methodological implications for technology mediated small group learning and learning analytics as a whole are then discussed.

Physiological Genomics, 2010

Previous in vitro studies found that nuclear factor erythroid-derived 2-like 1 (NFE2L1) was invol... more Previous in vitro studies found that nuclear factor erythroid-derived 2-like 1 (NFE2L1) was involved in mediating ascorbic acid-induced osterix expression and osteoblast differentiation via binding to the antioxidant response element of the osterix promoter. To test the role of NFE2L1 in regulating bone formation in vivo, we disrupted NFE2L1 specifically in osteoblasts. Mice expressing Cre under the control of Col1alpha2 promoter were crossed with NFE2L1 loxP mice to generate Cre+ knockout (KO) and Cre- wild-type (WT) mice. Skeletal measurements by DEXA revealed 8-10% and 9-11% reduction in total body BMC and bone area in the KO mice from 3 to 8 wk of age. Peripheral quantitative computed tomography analyses found both periosteal and endosteal circumferences were reduced by 6% at the middiaphysis of the femurs from 8 wk old KO mice. Histomorphometric analyses revealed reduced bone formation was a cause for reduced bone size in the KO mice. Microcomputed tomography analysis of the metaphysis of the femur revealed that trabecular bone volume/total volume, and trabecular numbers were decreased by 30 and 53% in the NFE2L1 KO mice. Expression of osterix was decreased by 57% in the bones of NFE2L1 KO mice. In vitro nodule assay demonstrated that mineralized nodule area was reduced by 68% in the cultures of bone marrow stromal cells from NFE2L1 KO mice. Treatment of primary osteoblasts with ascorbic acid increased osterix expression by fourfold, whereas loss of NFE2L1 in osteoblasts diminished ascorbic acid stimulation of osterix expression by 50%. Our data provide the first in vivo experimental evidence that NFE2L1 produced by osteoblasts is involved in regulating osterix expression, osteoblast differentiation, and bone formation.

Physical Chemistry Chemical Physics, 2013

Microporous carbon materials with extremely small pore size are prepared by employing polyaniline... more Microporous carbon materials with extremely small pore size are prepared by employing polyaniline as a carbon precursor and KOH as an activating agent. CO 2 sorption performance of the materials is systematically investigated at the temperatures of 0, 25 and 75 1C. The prepared carbons show very high CO 2 uptake of up to 1.86 and 1.39 mmol g À1 under 1 bar, 75 1C and 0.15 bar, 25 1C, respectively.

Physica C: Superconductivity, 1993

Molecular and Cellular Biology, 2010

Mutations of ephrin B1 in humans result in craniofrontonasal syndrome. Because little is known of... more Mutations of ephrin B1 in humans result in craniofrontonasal syndrome. Because little is known of the role and mechanism of action of ephrin B1 in bone, we examined the function of osteoblast-produced ephrin B1 in vivo and identified the molecular mechanism by which ephrin B1 reverse signaling regulates bone formation. Targeted deletion of the ephrin B1 gene in type 1alpha2 collagen-producing cells resulted in severe calvarial defects, decreased bone size, bone mineral density, and trabecular bone volume, caused by impairment in osterix expression and osteoblast differentiation. Coimmunoprecipitation of the TAZ complex with TAZ-specific antibody revealed a protein complex containing ephrin B1, PTPN13, NHERF1, and TAZ in bone marrow stromal (BMS) cells. Activation of ephrin B1 reverse signaling with soluble EphB2-Fc led to a time-dependent increase in TAZ dephosphorylation and shuttling from cytoplasm to nucleus. Treatment of BMS cells with exogenous EphB2-Fc resulted in a 4-fold increase in osterix expression as determined by Western blotting. Disruption of TAZ expression using specific lentivirus small hairpin RNA (shRNA) decreased TAZ mRNA by 80% and ephrin B1 reverse signaling-mediated increases in osterix mRNA by 75%. Knockdown of NHERF1 expression reduced basal levels of osterix expression by 90% and abolished ephrin B1-mediated induction of osterix expression. We conclude that locally produced ephrin B1 mediates its effects on osteoblast differentiation by a novel molecular mechanism in which activation of reverse signaling leads to dephosphorylation of TAZ and subsequent release of TAZ from the ephrin B1/NHERF1/TAZ complex to translocate to the nucleus to induce expression of the osterix gene and perhaps other osteoblast differentiation genes. Our findings provide strong evidence that ephrin B1 reverse signaling in osteoblasts is critical for BMS cell differentiation and bone formation.

Desalination, 2008

This study investigated the performance of four different membrane bioreactor (MBR) systems, name... more This study investigated the performance of four different membrane bioreactor (MBR) systems, namely floating media biofilter-crossflow microfiltration (FMB-CFMF) system, submerged membrane bioreactor (SMBR) alone, submerged membrane adsorption bioreactor (SMABR) and sponge-SMBR system, in terms of critical flux. The results indicated that FMB could be used as a pretreatment unit prior to MBR in order to minimize membrane fouling when the FMB-CFMF system operates under sub-critical flux condition. The addition of powdered activated carbon (PAC) could maintain the sustainable flux at a lower TMP value (7.5 kPa). However, irreversible fouling occurred when the filtration flux exceeded the critical flux. The addition of 10% volume (reactor volume) fraction of sponge could increase sustainable flux of SMBR system to 2 times.

Bioresource Technology, 2008

In this study, the performances of GAC adsorption and GAC bioadsorption in terms of dissolved org... more In this study, the performances of GAC adsorption and GAC bioadsorption in terms of dissolved organic carbon (DOC) removal were investigated with synthetic biologically treated sewage effluent (BTSE), synthetic primary treated sewage effluent (PTSE), real BTSE and real PTSE. The main aims of this study are to verify and compare the efficiency of DOC removal by GAC (adsorption) and acclimatized GAC (bioadsorption). The results indicated that the performance of bioadsorption was significantly better than that of adsorption in all cases, showing the practical use of biological granular activated carbon (BGAC) in filtration process. The most significance was observed at a real PTSE with a GAC dose of 5 g/L, having 54% and 96% of DOC removal by adsorption and bioadsorption, respectively. In addition, it was found that GAC adsorption equilibrium was successfully predicted by a hybrid Langmuir-Freundlich model whilst integrated linear driving force approximation (LDFA) + hybrid isotherm model could describe well the adsorption kinetics. Both adsorption isotherm and kinetic coefficients determined by these models will be useful to model the adsorption/bioadsorption process in DOC removal of BGAC filtration system.

Australian Dental Journal, 2012

The aim of this study was to evaluate the effect of halogen light irradiation on hydrogen peroxid... more The aim of this study was to evaluate the effect of halogen light irradiation on hydrogen peroxide (HP) bleaching by assessing HP concentrations, tooth whitening efficacy, and temperature variations in bleaching agents and pulp chambers. Sixteen premolars were randomly divided into two groups: Group BL (bleaching agent with halogen light irradiation for 3 × 10 minutes) and Group B (bleaching agent alone). HP concentrations were tested before and after treatment. CIE L*a*b* values of specimens were obtained using a spectrophotometer. Temperatures of bleaching gels and pulpal chambers were recorded by a digital multimeter with K-type thermocouple. Data were analysed using ANOVA and paired t-test. After treatment, HP concentration in group BL was slightly higher than that in group B. Paired t-tests revealed significant differences of ΔE between groups BL and B in all time intervals except at day 35. The temperature rise of bleaching gels and pulpal chambers in group BL was significantly higher than that in group B. In-office bleaching was effective for tooth whitening. The involvement of halogen light was beneficial for the immediate whitening effect but had little impact on the long-term whitening effect.

Proceedings of the Fifth International Conference on Learning Analytics And Knowledge - LAK '15, 2015

The goal of the present study was to uncover new insights about the learning analytics community ... more The goal of the present study was to uncover new insights about the learning analytics community by analyzing Twitter archives from the past four Learning Analytics and Knowledge (LAK) conferences. Through descriptive analysis, interaction network analysis, hashtag analysis, and topic modeling, we found: extended coverage of the community over the years; increasing interactions among its members regardless of peripheral and in-persistent participation; increasingly dense, connected and balanced social networks; and more and more diverse research topics. Detailed inspection of semantic topics uncovered insights complementary to the analysis of LAK publications in previous research.