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Tutoring involves providing learners with a suitable level of structure and guidance to support their learning. This study reports on an exploration of how to design such structure and guidance (i.e., learning scaffolds) in the Chinese online educational context, and in so doing, answer the following two questions: (a) What scaffolding strategies are needed to design online tutoring, and (b) How should different levels of scaffolding intensity be emphasized in different stages of online tutoring in such educational contexts? A model for online tutoring using the Community of Inquiry framework was developed and implemented in this study. It focused attention on both the critical role of the tutor in online learning and the importance of scaffolding in online tutoring. Both qualitative and quantitative methods were used to collect data, including questionnaires, interviews, and content analysis. In considering the variation of scaffolding throughout the online course, results showed that: (a) As long as a high degree of social presence is established in the initial phase, scaffolds for social presence can be withdrawn gradually throughout the course; (b) High-intensity teaching presence is much more important in the mid-phase of the course than in other phases; (c) "Discourse facilitation" should be emphasized for teaching presence in the mid-phase, while "direct instruction" scaffolding is needed in the last phase; and (d) The greatest need for scaffolding of cognitive presence occurs in the final phase of the course.

Due to being lightweight, fine-grained sediments easily flow with water and thus amplify the destructive effect of debris flow hazards. In such hazards, water content and shear strength are key inter-controlled factors relating to the stability of fine-grained sediments and thus control the density, scale, and danger of debris flow hazards. Although the correlation between water content and sediment stability has been studied, there are still some issues to be solved: what is the changing trend of shear strength with increasing water content? What is the water content spatial distribution pattern of fine-grained sediments in debris flow? What is the role/impact of this pattern on debris flow hazards prevention? Therefore, the objective of this research is to show the spatial distribution pattern of water content and establish a correlation between the water content and the shear strength of fine-grained sediments to provide a scientific basis for debris flow hazard prevention. Taking the Beichuan debris flow for our study, with a length of 37.6 km, and a 341 km2 study area, the results show that (1) the average water content shows an increasing trend, from 9.9% in the upstream of the river (SP01–SP05) to 21.7% in the downstream of the river (SP13–SP15). (2) When unsaturated, the correlation between the water content and shear strength is determined by combining the cohesion, normal stress, and internal friction angle; when saturated, the water content is negatively correlated with shear strength. (3) Water content and shear strength are the key inter-controlled factors relating to the stability of fine-grained sediments, and the water content distribution pattern of this research indicates the key locations that require attention: locations with high water content in the downstream river or with high curvature, which is of some significance for debris flow hazard prevention. [ABSTRACT FROM AUTHOR]

Litchi chinensis Sonn (Litchi) has been listed in the Chinese Pharmacopeia, and is an economically and medicinally valuable species within the family Sapindaceae. However, the material basis of its pharmacological action and the pharmacodynamic substances associated with its hypoglycemic effect are still unclear. The predominant objective of this study was to establish the fingerprint profile of litchi leaves and to evaluate the relationship between the components of the high‐performance liquid chromatography (HPLC) fingerprint of litchi leaves, assess its hypoglycemic effect by measuring α‐glucosidase and α‐amylase inhibition, and find the spectrum–effect relationship of litchi leaves by bivariate correlation analysis, Grey relational analysis and partial least squares regression analysis. In this study, the fingerprint of litchi leaves was established by HPLC, and a total of 15 common peaks were identified that clearly calibrated eight components, with P1 being gallic acid, P2 being protocatechuic acid, P3 being catechin, P6 being epicatechin, P12 being rutin, P13 being astragalin, P14 being quercetin and P15 being kaempferol. The similarities between the fingerprints of 11 batches of litchi leaves were 0.766–0.979. Simultaneously, the results of the spectrum–effect relationship showed that the chemical constituents represented by peaks P8, P3, P12, P14, P2, P13, and P11 were relevant to the hypoglycemic effect. [ABSTRACT FROM AUTHOR]

We synthesized BiVO4 mesocrystals with ordered assembly structure, and studied the structural order and the relationship between the photodegradation of Rhodamine B. Au nanoparticles (NPs) were successfully loaded onto Meso-BiVO4 by light-assisted induction, and Cd nanoparticles were further selected to be deposited on Au nanoparticles to form Z-scheme photocatalyst Meso-BiVO4-Au-CdS heterostructures. We try and propose to analyze its ordered assembly structure by XRD for the first time. The results show that Meso-BiVO4 is a mesocrystal with highly exposed (001) plane and directional assembly structure. The charge separation efficiency of all samples was studied by PL spectroscopy. The results show that the Z-scheme Meso-BiVO4-Au-CdS can promote the charge separation and obtain the best carrier separation efficiency. Thus, it has the best photocatalytic activity in the experiment of photocatalytic degradation of rhodamine B. The main active species in the degradation process were confirmed by free radical trapping experiment, and the degradation mechanism was put forward. [ABSTRACT FROM AUTHOR]

Inspired by the layered structure, light absorption, and charge carrier pathway of chloroplast thylakoids in natural photosynthesis, we propose a novel artificial photosynthesis platform, which is composed of layered structured vaterite as the scaffold with gold nanoparticles (AuNPs), photosensitizer eosin Y (EY), and redox enzyme L-glutamate dehydrogenase (GDH) as the functional components. The EY exhibited significantly enhanced light absorption and charge carrier generation due to the localized surface plasmon resonance (LSPR) around the AuNPs and light refraction within the layers. This artificial photosynthesis platform can regenerate reduced nicotinamide adenine dinucleotide (NADH) under visible light and promote the rapid conversion of α-ketoglutarate to L-glutamate (0.453 Mm/h). The excellent biocompatibility of layered vaterite significantly enhances the resistance of GDH to harsh conditions, including high pH (pH = 10) and elevated temperatures (37–57 °C). [ABSTRACT FROM AUTHOR]

The degradation of simulated methyl red dye wastewater in a concentric tubular reactor using dielectric barrier discharge low-temperature plasma technology was studied. The effects of discharge power, initial solution concentration, initial pH, treatment time, and atmospheric conditions on the degradation efficiency were studied. The color, pH, and absorbance of methyl red at 521 nm were used to detect the dye concentration, analyze the degradation process, and propose a degradation mechanism for methyl red. The results indicate that (1) in this experiment, the discharge power affects the degradation of methyl red but is limited by temperature and humidity, such that there is no positive correlation between the discharge power and the treatment effect. Therefore, the treatment of the solution at a low discharge power of 115 W is preferable; (2) the higher the initial concentration, the longer the time needed to achieve the same degradation rate as that achieved at lower concentrations; and (3) under the same conditions, a low pH is conducive to the degradation of methyl red, and acidic conditions are conducive to the bond breaking of methyl red.