Systematic Microwave-Assisted Postsynthesis of Mn-Doped Cesium Lead Halide Perovskites with Improved Color-Tunable Luminescence and Stability

The metal doping at the Pb2+ position provides improved luminescence performance for the cesium lead halide perovskites, and their fabrication methods assisted by microwave have attracted considerable attention due to the advantages of fast heating and low energy consumption. However, the postsynthetic doping strategy of the metal-doped perovskites driven by microwave heating still lacks systematic research. In this study, the assembly of CsPbBr3/CsPb2Br5 with a strong fluorescence peak at 523 nm is used as the CsPbBr3 precursor, and through the optimization of the postsynthetic conditions such as reaction temperatures, Mn2+/Pb2+ feeding ratios, and Mn2+ sources, the optimum Mn2+-doped product (CsPb(Cl/Br)3:Mn) is achieved. The exciton fluorescence peak of CsPb(Cl/Br)3:Mn is blueshifted to 437 nm, and an obvious fluorescence peak attributing to the doped Mn2+ ions at 597 nm is obtained. Both the CsPbBr3 precursor and CsPb(Cl/Br)3:Mn have high PLQY and stability because there are CsPb2Br5 microcubic crystals to well disperse and embed the CsPbBr3 nanocrystals (NCs) in the precursor, and after Mn2+-doping, this structure is maintained to form CsPb(Cl/Br)3:Mn NCs on the surface of their microcrystals. The exploration of preparation parameters in the microwave-assisted method provides insights into the enhanced color-tunable luminescence of the metal-doped perovskite materials

Effect of the Electronic Structure on the Stability of CdSe/CdS and CdSe/CdS/ZnS Quantum-Dot Phosphors Incorporated into a Silica/Alumina Monolith

In this letter, we prepare ultrastable quantum-dot (QD)-based phosphors. Furthermore, we find that type I CdSe/CdS/ZnS QDs are fairly stable during the thermal annealing process of a QD–SiO₂/Al₂O₃ monolith (SAM) phosphor, but quasi-type II CdSe/CdS QDs easily lose their emission possibly because the delocalized electrons to the shell are more susceptible to being captured by the surface trap sites. The light-emitting diode (LED) encapsulated with a CdSe/CdS/ZnS QD–SAM phosphor on the blue LED chip can maintain approximately 90% of its initial intensity after 450 h, in contrast, the light intensity of the reference LED using a CdSe/CdS/ZnS QD decreases to approximately 41%

Near-infrared responsive Z-scheme heterojunction with strong stability and ultra-high quantum efficiency constructed by lanthanide-doped glass

Lanthanide-doped near-infrared (NIR) photocatalyst still obstructed by the less impressive photocatalytic efficiency and stability. In this work, we report a novel strategy by introducing the lanthanide-doped ferroelectric perovskites of SiTiO3 and Sr2Bi4Ti4O15 into the glass-ceramic (GC), then an efficient and stable NIR photocatalyst was fabricated through the method of facile in-situ HCl etching GC. The results show that Sr2Bi4Ti4O15, SrTiO3, and BiOCl were exposed to the superficial coating of the core-shell structured photocatalyst and constructed Zscheme heterojunction, the heterojunction with built-in electric field could significantly facilitate the charge carriers separation and harvest NIR light for photocatalytic reaction simultaneously. The evident increase of Lewis basic sites over defect-rich photocatalyst is found, the center dot O2- and center dot OH radicals are generated. During the degradation of norfloxacin (NOR) under NIR light irradiation for 90 min, the NOR degradation rate is 86% (TOC removal rate is 30.7%), the high apparent quantum yield of 2.3% is achieved

Near-infrared responsive Z-scheme heterojunction with strong stability and ultra-high quantum efficiency constructed by lanthanide-doped glass

Lanthanide-doped near-infrared (NIR) photocatalyst still obstructed by the less impressive photocatalytic efficiency and stability. In this work, we report a novel strategy by introducing the lanthanide-doped ferroelectric perovskites of SiTiO3 and Sr2Bi4Ti4O15 into the glass-ceramic (GC), then an efficient and stable NIR photocatalyst was fabricated through the method of facile in-situ HCl etching GC. The results show that Sr2Bi4Ti4O15, SrTiO3, and BiOCl were exposed to the superficial coating of the core-shell structured photocatalyst and constructed Zscheme heterojunction, the heterojunction with built-in electric field could significantly facilitate the charge carriers separation and harvest NIR light for photocatalytic reaction simultaneously. The evident increase of Lewis basic sites over defect-rich photocatalyst is found, the center dot O2- and center dot OH radicals are generated. During the degradation of norfloxacin (NOR) under NIR light irradiation for 90 min, the NOR degradation rate is 86% (TOC removal rate is 30.7%), the high apparent quantum yield of 2.3% is achieved

A New Smart 2-Min Mobile Alerting Method for Mild Cognitive Impairment Due to Alzheimer’s Disease in the Community

The early identification of mild cognitive impairment (MCI) due to Alzheimer’s disease (AD), in an early stage of AD can expand the AD warning window. We propose a new capability index evaluating the spatial execution process (SEP), which can dynamically evaluate the execution process in the space navigation task. The hypothesis is proposed that there are neurobehavioral differences between normal cognitive (NC) elderly and AD patients with MCI reflected in digital biomarkers captured during SEP. According to this, we designed a new smart 2-min mobile alerting method for MCI due to AD, for community screening. Two digital biomarkers, total mission execution distance (METRtotal) and execution distance above the transverse obstacle (EDabove), were selected by step-up regression analysis. For the participants with more than 9 years of education, the alerting efficiency of the combination of the two digital biomarkers for MCI due to AD could reach 0.83. This method has the advantages of fast speed, high alerting efficiency, low cost and high intelligence and thus has a high application value for community screening in developing countries. It also provides a new intelligent alerting approach based on the human–computer interaction (HCI) paradigm for MCI due to AD in community screening

Enhancement of β-Lactam-Mediated Killing of Gram-Negative Bacteria by Lysine Hydrochloride

ABSTRACT Widespread bacterial resistance among Gram-negative bacteria is rapidly depleting our antimicrobial arsenal. Adjuvants that enhance the bactericidal activity of existing antibiotics provide a way to alleviate the resistance crisis, as new antimicrobials are becoming increasingly difficult to develop. The present work with Escherichia coli revealed that neutralized lysine (lysine hydrochloride) enhances the bactericidal activity of β-lactams in addition to increasing bacteriostatic activity. When combined, lysine hydrochloride and β-lactam increased expression of genes involved in the tricarboxylic acid (TCA) cycle and raised reactive oxygen species (ROS) levels; as expected, agents known to mitigate bactericidal effects of ROS reduced lethality from the combination treatment. Lysine hydrochloride had no enhancing effect on the lethal action of fluoroquinolones or aminoglycosides. Characterization of a tolerant mutant indicated involvement of the FtsH/HflkC membrane-embedded protease complex in lethality enhancement. The tolerant mutant, which carried a V86F substitution in FtsH, exhibited decreased lipopolysaccharide levels, reduced expression of TCA cycle genes, and reduced levels of ROS. Lethality enhancement by lysine hydrochloride was abolished by treating cultures with Ca2+ or Mg2+, cations known to stabilize the outer membrane. These data, plus damage observed by scanning electron microscopy, indicate that lysine stimulates β-lactam lethality by disrupting the outer membrane. Lethality enhancement of β-lactams by lysine hydrochloride was also observed with Acinetobacter baumannii and Pseudomonas aeruginosa, thereby suggesting that the phenomenon is common among Gram-negative bacteria. Arginine hydrochloride behaved in a similar way. Overall, the combination of lysine or arginine hydrochloride and β-lactam offers a new way to increase β-lactam lethality with Gram-negative pathogens. IMPORTANCE Antibiotic resistance among Gram-negative pathogens is a serious medical problem. The present work describes a new study in which a nontoxic nutrient increases the lethal action of clinically important β-lactams. Elevated lethality is expected to reduce the emergence of resistant mutants. The effects were observed with significant pathogens (Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa), indicating widespread applicability. Examination of tolerant mutants and biochemical measurements revealed involvement of endogenous reactive oxygen species in response to outer membrane perturbation. These lysine hydrochloride–β-lactam data support the hypothesis that lethal stressors can stimulate the accumulation of ROS. Genetic and biochemical work also revealed how an alteration in a membrane protease, FtsH, abolishes lysine stimulation of β-lactam lethality. Overall, the work presents a method for antimicrobial enhancement that should be safe, easy to administer, and likely to apply to other nutrients, such as arginine