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Carbon dots (CDs) have been studied for years as one of the most promising fluorescent nanomaterials. Herein, fluorescent CDs excited by visible light emitted red fluorescence with a quantum yield of 32.8% via a facile hydrothermal treatment. In addition to being applied in cell imaging, the as-prepared CDs were also utilized in the detection of ammonia and formaldehyde in aqueous solutions because of their pH-dependent properties, with a low limit of detection of 3.7 nM and 44 μM, respectively. Furthermore, we synthesized flexible and transparent fluorescence films by mixing the as-prepared CDs and PVB powder, which can be utilized to directly detect ammonia gas under visible light according to significant colour changes. Therefore, the as-prepared CDs would have more prominent and influential application in clinical diagnostics and environmental analysis.

Highly ordered metal nanoclusters (NCs) have attracted much attention due to their controllability and regularity. Herein, self-assembled CuNCs with orange-red emission were prepared using m-aminothiophenol (m-AT) within 10 s. The hydrogen bonding interactions of CuNCs@m-AT were controlled precisely by adjusting the pH, and this induced the continuous self-assembly process of monodisperse, nano-spheres, nano-meshes and nano-sheets, and established the relationship between the macrostates and the microstructures of CuNCs@m-AT. For the first time, an organic anion was used to induce the emission of CuNCs@m-AT and to carry out the phase transfer of CuNCs@m-AT from the aqueous phase to the n-butanol phase. In addition, we found that m-AT was more beneficial for the synthesis of CuNCs, compared to o-AT and p-AT. This work provides an example of the structure-dependent CuNCs@m-AT on luminescent properties and showed the potential of –NH2 in the design of superstructures of nanoscale materials with unique functions and properties.

Herein, we directly prepared white fluorescent CDs (W-CDs) using 1,6-dihydroxynaphthalene (1,6-DHN) and l -asparagine ( l -Asn) as carbon sources through a simple solvent-free method. As-prepared W-CDs can be obtained in high yield (95%). A relative pure white LEDs (WLEDs) were fabricated with Commission Internationale de L’Eclairage (CIE) coordinates of (0.32, 0.31). As-prepared W-CDs will have promising future for a wide range of optoelectronic devices.

The color-tunable AuAg nanoclusters (AuAg NCs) are designed by adjusting the location of Ag element, in which β-lactoglobulin (β-Lg) serves as the capping and reducing agent. The mono-metal Au NCs emit red-fluorescent emission (red-Au NCs@β-Lg); however, the stronger metallophilic interaction between Au and Ag facilitate the smaller size, and then the bimetal AuAg NCs@β-Lg present yellow emission (yellow-AuAg NCs@β-Lg). A “Ag+ shell” outside the AuAg NCs@β-Lg cause the emission change to orange (orange-AuAg NCs@β-Lg-Ag+). This is the first time for Ag+ to tune continuously the emission wavelength of AuAg NCs. TEM proves that the size of particle has a close relationship with the fluorescence emissions. l -cysteine (Cys) stabilized the protective effect of β-Lg and shows a “turn on” effect on the fluorescence intensity of yellow-AuAg NCs@β-Lg. In contrary, the strong interaction between Cys and Ag+ destroys the protection of β-Lg to the core of yellow-AuAg NCs@β-Lg and shows a distinct “turn off” effect on the fluorescence intensity of orange-AuAg NCs@β-Lg-Ag+. The above phenomenon has been successfully applied to the detection of Cys in the Hela cells. This location-based color-tunable strategy is expected to open up a new potential to improve the performance of NCs.

Additional file 1: Method S1. Region-of-interest delineation. Method S2. Radiomic feature definition and calculation. Method S3. Radiomic feature selection. Method S4. Biomarker development. Table S1. Summary of selected radiomic features. Table S2. Cross validation of the radiomics model. Figure S1. Variable importance of the selected radiomic features

Fluorescence has been extensively employed for visual detection; however, it is inconvenient for people to distinguish single-color fluorescence changes. Herein, a dual-signal ratiometric fluorescent probe of a carbon quantum dot/gold nanocluster (CQD/Au NC) nanosystem for sensitive and selective detection of Ag+ and L-cysteine (Cys) was established. The CQDs with blue fluorescence at 472 nm served as a reference signal and Au NCs with orange fluorescence at 605 nm functioned as a reporter. From zeta potential measurements and TEM images, there was no indication of interaction between the two materials due to electrostatic repulsion. Upon adjusting the proportion of the CQDs and Au NCs, the nanosystem emitted a gray-orange emission at a single excitation wavelength. Ag+ enhanced the orange colour of Au NCs, but Cys could quench it completely with the high affinity of the coordination interaction between Cys and Ag+, while the blue fluorescence of CQDs was not affected. Therefore, the fluorescence of the nanosystem showed gray orange to light orange colour for determination of Ag+, and light orange to blue colour for determination of Cys. Moreover, paper-based visual detection was successfully carried out, which showed a more distinguishable color difference than that in aqueous solution. Our method has bright potential for application in the real-time and online visual detection of Ag+ and Cys in the future.

Background Perioperative safety in China is unclear. This study aims to develop a seamless safety management system to ensure patient safety in each period by improving team communication, consistency of care, and safety culture. Methods Five hospitals representing top medical treatment level in regions with different economic development were included. The study (June, 2014, to June, 2017) consists of three phases: baseline survey, intervention policy development and implementation, and effect assessment after intervention. All surgical departments (excluding ophthalmologics and orthopaedics) including more than 4000 members of staff or more are involved, and 80 000 inpatients aged 14 years or older are to be enrolled. Complication indices were selected from existing complication indices by a team of 246 specialists. 314 of 537 indices were retained after three rounds of selection. A case report form was formulated by a team of experienced doctors, anaesthetists, nurses, and statisticians. Data are being obtained with an electronic data capture system consisting of four distinct units: the ward, operating room, anaesthesia unit, and intensive-care unit. A pilot study was done to train staff. Assessment of quality control was done by statisticians. The development of intervention measure will be guided by study finding, and the WHO surgical checklist will be incorporated after modification. The whole intervention process will be implemented using an electronic network platform. This research was approved by ethics committee of Peking Union Medical College Hospital, Beijing, China. Findings By April 22, 2015, 15 675 patients (6082 [38·8%] of whom were men; median age 48 years [IQR 36–60]) have been enrolled. 1301 (8·3%) patients have an American Society of Anesthesiologists score of III or more, and 3135 (20·0%) patients had operation risk grading of III or more. Overall, the five surgeries with the highest rates of complications (including those potentially associated with anaesthesia) are cardiac (153 [15·6%]), hepatobiliary pancreatic (80 [8·0%]), chest (39 [7·8%]), vascular (18 [7·1%]), and neurosurgery (45 [4·6%]). Complications rate in the intensive-care unit is 24·6% (114 of 463). Highest complication rates are seen in patients aged 70 years or older, those with cardiovascular disease history, and those with high operation risk grading. Interpretation It is imperative to improve perioperative safety and reduce occurrence of serious complications in China. Safety management system should be constructed in a tailored, hierarchical, and user-friendly way. Funding This research is funded by National Health and Family Planning Commission of China.