A UV light activated SnO2 thin film nitrogen dioxide sensor was fabricated by DC sputtering and oxidation. It can be directly placed in the air to detect the concentration of NO2 at RT, with a detection limit of 5 ppb. Experiments show that the sensor has good selectivity and stability. SEM, XRD, and TEM characterization indicate that the sample is mainly composed of tetragonal rutile phase SnO2. The surface presents a rough and porous granular structure, which is suitable for gas adsorption. The effect of operating temperature on NO2 sensing of SnO2 thin film gas sensor was systematically investigated. Therefore, the fabricated SnO2 thin film NO2 sensor has the promise to greatly reduce power consumption and can be used in a wider range of fields because of its characteristic that it can work normally at RT.

Objective: This study aimed to evaluate the role of collagen cross-linkers in the bonding performance of the resin-dentin interface through a systematic review and a network meta-analysis.Sources: The literature search was conducted in several databases like PubMed, EMBASE, Cochrane, Scopus and Web of Science from their inception till 30 April 2022.Study selection: The inclusion criteria consisted of in vitro studies evaluating the micro-tensile and micro-shear bond strengths of different cross-linkers acting on dentin. Bayesian network meta-analysis was conducted using RStudio.Data: Out of the 294 studies evaluated in the full-text analysis, 40 were included in the systematic review and meta-analysis. Most studies have used cross-linkers as primer (65.1%), followed by incorporating them into in adhesives and acid etching agents. The application methods of the adhesive system were classified as “etch-and-rinse (ER) adhesives” (77%) and “self-etching (SE) adhesives”. Moreover, there were six types of cross-linkers in this presented review, of which the most numerous were polyphenols.Conclusion: Different application methods of cross-linkers, the long-term results showed that were only effective when used for longer durations, the immediate results were not statistically different. According to immediate and long-term results, etch-and-rinse (ER) adhesives showed a greater bonding performance than the control groups (p ≤ 0.05), whereas self-etching (SE) adhesives showed similar bond strength values (p ≥ 0.05). The result of network meta-analysis (NMA) showed that Dope like compound showed higher long-term bonding performance than other cross-linkers.Clinical significance: Long-term clinical studies may be needed to determine the effect of the cross-linkers on the bonding properties.

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