Ion Substitution Strategy toward High-Efficiency Near-Infrared Photoluminescence of Cs2KIn1-yAlyF6:Cr3+ Solid Solutions.

The rising demand for portable near-infrared (NIR) light sources has accelerated the exploration of NIR luminescent materials with high efficiency and excellent thermal stability. Inspired by the structural-modulated ion substitution strategy, herein, a high-performance Cs2KIn0.8Al0.1F6:0.1Cr3+ phosphor with a peak at 794 nm and full width at half-maximum (fwhm) of 117 nm was successfully synthesized by introducing Al3+ ions. The high performance is reflected in its high internal quantum efficiency (IQE) of 88.06% and good thermal quenching resistance (I423K = 71.64%). Compared with the initial Cs2KInF6:0.1Cr3+, the IQE and thermal stability are improved by 16.67% and 72.54%, which stem from the enhanced crystallinity and the strengthened structural rigidity. Finally, a phosphor-converted light-emitting diode (pc-LED) with a superior NIR photoelectric efficiency (21.04%@320 mA) was fabricated. Meanwhile, the pupil tracking, anticounterfeiting, intelligent identification, and bioimaging were successfully demonstrated. This work provides new perspectives for synthesizing efficient NIR fluoride phosphors and designing diverse applications.

Role of extracellular polymeric substances in metal sequestration during mangrove restoration.

Extracellular polymeric substances (EPS) are widely observed in aquatic ecosystems, however the potential function of EPS on metal sequestration in mangrove wetlands is unclear. Thus, an ecological restoration area (including Sonneratia apetala, Kandelia obovata and unvegetated mudflat) was employed to assess the effect of mangrove reforestation on metal sequestration and the underlying roles played by EPS. The results showed that mangrove restoration directly promoted metal accumulation (e.g., Cr, Cu, Ni, Pb, and Zn) in sediments. However, alleviated metal bioavailability was detected after mangrove reforestation. The changes in metal accumulation and bioavailability were highly correlated with EPS and microbial composition. Mangrove restoration (especially for K. obovata reforestation) also significantly promoted EPS production, in which multiple metal-chelating functional groups (e.g., hydroxyl, carboxyl, and imino) were identified by Fourier infrared spectra. Moreover, the contents of EPS were positively correlated with metal accumulation but negatively correlated with metal bioavailability. The present data further illustrated that the enhancements of Gammaproteobacteria, Bacteroidia, Desulfobulbia, and Desulfobacteria might be important for EPS production. In summary, this is the first study to reveal that the presence of artificial mangroves might act as an efficient barrier in metal sequestration and immobilization by enhancing inherent microbial EPS.

A New Evaluation Method for Medical Image Information Hiding Techniques.

Medical image scans and associated electronic medical records (EMR) could be stored locally or transmitted for use in autodiagnosis and remote healthcare in teleradiology. Hence, they require security against unauthorised access and modification. Among other means of providing this security, information hiding (IH) techniques have gained relevance especially for open networks that are prone to active attacks. However, the evaluation of the suitability of these IH algorithms in terms of preserving medical image diagnostic features is currently limited to signal processing parameters. This paper re-interprets existing evaluation parameters and provides a new framework that allows dynamic selection of medical image IH (watermarking and steganography) security algorithms. Specifically, criteria that capture medical statistics used in the diagnosis and monitoring of patients were incorporated. These criteria and framework were validated on the Pneumonia Chest Xray dataset (used in a Kaggle Competition) using three selected IH algorithms that offer privacy and image tamper detection.

Unified Fine-Grained Access Control for Personal Health Records in Cloud Computing.

Attribute-based encryption has been a promising encryption technology to secure personal health records (PHRs) sharing in cloud computing. PHRs consist of the patient data often collected from various sources including hospitals and general practice centres. Different patients' access policies have a common access sub-policy. In this paper, we propose a novel attribute-based encryption scheme for fine-grained and flexible access control to PHRs data in cloud computing. The scheme generates shared information by the common access sub-policy, which is based on different patients' access policies. Then, the scheme combines the encryption of PHRs from different patients. Therefore, both time consumption of encryption and decryption can be reduced. Medical staff require varying levels of access to PHRs. The proposed scheme can also support multi-privilege access control so that medical staff can access the required level of information while maximizing patient privacy. Through implementation and simulation, we demonstrate that the proposed scheme is efficient in terms of time. Moreover, we prove the security of the proposed scheme based on security of the ciphertext-policy attribute-based encryption scheme.