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Collaborative problem-solving (CPS) engages students in solving ill-structured problems, creating group knowledge, and developing self-regulation and collaboration skills. Different scaffoldings, such as minimal-guided, task-oriented, and idea-oriented, can be used to facilitate students' CPS activities, but their effects have not been comprehensively explored. In this research, we use minimally-guided, task-oriented, and idea-oriented scaffoldings to promote Chinese university students' online CPS activities and use a multi-method approach to analyze the effects of three scaffolding on collaboration. The results indicate relatively complicated collaborative processes and outcomes supported by three scaffoldings. It is initially shown that the idea-centered scaffolding strengthens students' connections between idea contribution, metacognitive regulation, and knowledge artifact behaviors, which are critical factors for improving the CPS quality. Based on the empirical research results, we conclude that future instructional design should carefully consider the educational culture, time constraint, and student regulation to better facilitate CPS practices.

Graphene nanoribbon is a novel variety of graphene with high length-to-width ratio and straight edges. Herein, we report an improved method for the synthesis of graphene oxide nanoribbons (GONRs) from longitudinal unraveling of multiwalled carbon nanotubes by means of a one-step, one-pot pressurized oxidation reaction. The obtained GONRs were characterized by different techniques. Furthermore, owing to their unique properties such as strong optical absorption and good water dispersibility, we show that GONRs can be used as an excellent matrix or probe in matrix-assisted or surface-enhanced laser desorption/ionization mass spectrometry (MALDI or SELDI MS) for the first time. In MALDI MS, GONRs generated significantly higher signals than conventional organic matrix and other graphene-based matrices in the detection of low-mass compounds. We also demonstrate the use of GONRs as a sensitive SELDI probe for simultaneous detection of multiple small molecules and profiling of small molecules in complex environmental samples, thus revealing its application potential in rapid screening of low-mass pollutants in complex media., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

To be mild! Mild oxidization of chemically converted graphene with diluted nitric acid produces low-oxidation and low-defect acid-oxidized graphene (AOG) material with excellent water dispersibility. In MALDI MS, the AOG matrix yielded significantly higher signals than graphene, graphene oxide, and conventional organic matrices for nonpolar analytes., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)