Novel optical materials are crucial for environmental monitoring. Metal nanoclusters ( metal NCs) , typically consisting of several to tens of metal atoms, have attracted more and more attention for recent years. Due to their ultrasmall size, strong fluorescence, low toxicity, excellent stability and unique core-shell structure, metal NCs have been considered as promising optical materials for the construction of excellent fluorescent sensors. In this review, we mainly focus on the recent progress in their applications in environmental monitoring, including the detection of pH, heavy metal ions, inorganic anions and nitroaromatic explosives.

Objective:To investigate the application in the preparation of supraclavicular island flap by "point line anterograde dissection (PLAD) ".Methods:A retrospective analysis was performed on 45 flaps of 43 patients treated with supraclavicular artery island flap from the Department of Otorhinolaryngology Head and Neck Surgery, Beijing Tongren Hospital Affiliated to Capital Medical University from January 2013 to June 2019. The patients were all male, aged 35-72 years old. There were 26 cases of hypopharyngeal cancer, 4 cases of recurrent laryngeal cancer, 2 cases of cervical esophageal cancer, 1 case of tonsillar cancer, 1 case of parotid gland cancer, 3 cases of postoperative pharyngeal fistula after hypopharyngeal cancer, 2 cases of esophageal fistula after trauma, 2 cases of esophageal stricture after hypopharyngeal carcinoma operation, 1 case of autoimmune laryngeal stenosis, and 1 case of cheek defect after maxillary sinus cancer operation."Point" was the origin of the supraclavicular artery in the transverse carotid artery. "Line" was an extension line made along the starting point of the supraclavicular vessel for anterograde anatomy of 1-2 cm and the direction of the blood vessel. The extension line was used as the central axis of the designed island flap. Characteristics of flap blood supply, the time of flap preparation, flap survival, donor area recovery and clinical follow-up were recorded.Results:The arterial blood supply of the flap was constant, and the venous reflux was variable. The area of the prepared flap was (4-8) cm×(10-18) cm, and the preparation time was 30-60 min, with a median of 42 min. Skin flap survival rate was 100%. Partial necrosis of skin flap occurred in 1 patient and postoperative pharyngeal fistula occurred in 5 patients, all of whom were cured by dressing change. The donor site defects were closed and sutured directly. 3 patients had partial incision dehiscence and healed after dressing change. During the follow-up, 1 patient was lost, and the remaining 42 patients were followed up for 8 to 55 months.40 patients involved swallowing function, all of them returned to regular diet or soft fluid after operation.40 patients involved malignant tumors and local tumor recurrence in 3 patients among whom, there were 2 cases of lymph node recurrence, and 2 cases of distant metastasis, including 1 case of lung metastasis and 1 case of bone metastasis.Conclusion:PLAD is a simple, safe and efficient method for the preparation of supraclavicular island flap.

Bacillus subtilis can be widely used as an important microorganism for metabolic engineering and recombinant proteins expression in industrial biotechnology and synthetic biology. However, it is difficult to make accurate regulation of exogenous gene by biological tools in B. subtilis, which limits the application of B. subtilis in synthetic biology. The purpose of this study is to develop regulatory tools for precise control of gene expression by using non-coding RNAs, by which the activation of heterologous gene could be achieved without the auxiliary protein factors. We constructed the synthetic riboswitch E and aptazyme AZ using the theophylline aptamer. Six different native promoters from B. subtilis were functionally adapted with the E and AZ to fabricate an array of novel regulatory elements activated by theophylline. Then, we determined the performance of these elements using green fluorescence protein as reporter, and then further verified using red fluorescence protein and pullulanase as cargo proteins. Results showed that the same kind of RNA elements with different promoters showed different levels of efficiency. Promoter PsigW and E combination (sigWE) had the highest induction rate in B. subtilis. Compared with the control group, it can produce the induction rate of 16.8. Promoter PrpoB and AZ combination (rpoBAZ) showed the highest induction rate of 6.2. SigWE mediated mCherry induction rate was 9.2, and P43E mediated pullulanase induction rate was 32.8, in which enzyme activity reached 81 U/mL. This study confirmed that GFP, mCherry and pullulan can all be regulated by riboswitch and aptazyme, but there were differences between different combinations of promoters with RNA regulators.
Bacillus subtilis ; Promoter Regions, Genetic ; RNA ; Recombinant Proteins ; Theophylline