Objective:To study the feasibility of the early diagnosis of chronic periodontitis using near-infrared diffuse correlation spectroscopy(DCS).Methods:30 subjects were inclded.The relative gingival blood flow(GBF) at the labial,mesial and distal healthy gingiva(the control) or the gingiva with periodontitis of maxillary anterior teeth was respectively measured by DCS before periodontal treatment,a week and a month after treatment.Results:The GBF of healthy gingiva group,gingivitis group and periodontitis group was 129.73 ± 10.70,95.51 ± 11.83 and 67.84 ± 13.05 respectively.Periodontal indexes were decreased and the relative GBF increased significantly 1 week and 1 month after treatment.Gingival index and sulcus bleeding index were respectively correlated to relative GBF(r =-0.902,r =-0.893).Conclusion:Near-infrared diffuse correlation spectroscopy can non-invasively detect the relative gingival blood flow in different stages of chronic periodontitis,it may be a method of early diagnosis of chronic periodontitis.

Enzyme-catalyzed CO₂ reduction to value-added commodities is important for alleviating the global environmental issues and energy crises due to high selectivity and mild conditions. Owing to high energy density, formic acid or methanol produced from CO₂ using formate dehydrogenase (FDH) or multi-enzyme cascades are promising target chemicals for CO₂ utilization. However, the low activity, poor stability and low reusability of key enzymes involved in such process hampered its large-scale application. Enzyme immobilization provides an effective solution to these problems and significant progress have been made in immobilization carriers. Moreover, integration of enzyme immobilization with other catalysis techniques have been explored extensively. This review summarized the recent advances in the immobilization of enzymes using membranes, inorganic materials, metal-organic frameworks, covalent organic frameworks and other carriers, and illustrated the characteristics and advantages of different immobilization materials and immobilization methods. The synergistic effects and applications of immobilized enzymes and electrocatalytic or photocatalytic coupling reaction systems for CO₂ reduction were further summarized. Finally, the current challenges of enzyme immobilization technology and coupling reaction systems were pointed out and their development prospects were presented.
Enzymes, Immobilized ; Carbon Dioxide ; Catalysis ; Formate Dehydrogenases ; Metal-Organic Frameworks