Synergic Surface Modifications of PbS Quantum Dots by Sodium Acetate in Solid-State Ligand Exchange toward Short-Wave Infrared Photodetectors.

PbS quantum dots (QDs) are promising for short-wave infrared (SWIR) photodetection and imaging. Solid-state ligand exchange (SSLE) is a low-fabrication-threshold QD solid fabrication method. However, QD treatment by SSLE remains challenging in seeking refined surface passivation to achieve the desired device performance. This work investigates using NaAc in the ligand exchange process to enhance the film morphology and electronic coupling configuration of QD solids. By implementing various film and photodetector device characterization studies, we confirm that adding NaAc with a prominent adding ratio of 20 wt % NaAc with tetrabutylammonium iodide (TBAI) in the SSLE leads to an improved film morphology, reduced surface roughness, and decreased trap states in the QD solid films. Moreover, compared to the devices without NaAc treatment, those fabricated with NaAc-treated QD solids exhibit an enhanced performance, including lower dark current density (<100 nA/cm2), faster response speed, higher responsivity, detectivity, and external quantum efficiency (EQE reaching 25%). The discoveries can be insightful in developing efficient, low-cost, and low-fabrication-threshold QD SWIR detection and imager applications.

Chiral perovskite-CdSe/ZnS QDs composites with high circularly polarized luminescence performance achieved through additive-solvent engineering.

Chiral perovskite materials are being extensively studied as one of the most promising candidates for circularly polarized luminescence (CPL)-related applications. Balancing chirality and photoluminescence (PL) properties is of great importance for enhancing the value of the dissymmetry factor (glum), and a higher glum value indicates better CPL. Chiral perovskite/quantum dot (QD) composites emerge as an effective strategy for overcoming the dilemma that achieving strong chirality and PL in chiral perovskite while at the same time achieving high glum in this composite is very crucial. Here, we choose diphenyl sulfoxide (DPSO) as an additive in the precursor solution of chiral perovskite to regulate the lattice distortion. How structural variation affects the chiral optoelectronic properties of the chiral perovskite has been further investigated. We find that chiral perovskite/CdSe-ZnS QD composites with strong CPL have been achieved, and the calculated maximum |glum| of the composites increased over one order of magnitude after solvent-additive modulation (1.55 × 10-3 for R-DMF/QDs, 1.58 × 10-2 for R-NMP-DPSO/QDs, -2.63 × 10-3 for S-DMF/QDs, and -2.65 × 10-2 for S-NMP-DPSO/QDs), even at room temperature. Our findings suggest that solvent-additive modulation can effectively regulate the lattice distortion of chiral perovskite, enhancing the value of glum for chiral perovskite/CdSe-ZnS QD composites.

Construction of a Pickering interfacial biocatalysis system in skim milk and enzymatic transesterification for enhancement of flavor and quality.

Despite considerable research efforts, lipase catalysis in a fluid milk system with aqueous multi-component mixtures containing multiple microphases, remains challenging. Pickering interfacial biocatalysis (PIB) platforms are typically fabricated with organic solvents/lipids and water. Whether a PIB with excellent catalytic performance can be constructed in complex milk mixtures remains unknown. Here, we challenged PIB with skim milk, and a small amount of flaxseed oil, and phytosterols as a model system for transesterification and lipolysis to enhance quality and flavor. The amino-modified mesoporous silica spheres (MSS-N) were employed as an emulsifier and carrier of lipase AYS (AYS@MSS-N). The conversion of phytosterol esters reached 75.5% at 1.5 h and prepared phytosterol ester-fortified milk with a content of 1.0 g/100 mL. The relative conversion rate remained above 70% after 6 cycles. In addition, the fortified milk showed an intensified and favorable effect on sensory traits through volatile flavor composition analysis. The findings provide a versatile alternative for PIB applications in complex environments, i.e., milk, which might inspire a new bioprocess strategy for dairy products.

Superlattice deformation in quantum dot films on flexible substrates via uniaxial strain.

The superlattice in a quantum dot (QD) film on a flexible substrate deformed by uniaxial strain shows a phase transition in unit cell symmetry. With increasing uniaxial strain, the QD superlattice unit cell changes from tetragonal to cubic to tetragonal phase as measured with in situ grazing-incidence small-angle X-ray scattering (GISAXS). The respective changes in the optoelectronic coupling are probed with photoluminescence (PL) measurements. The PL emission intensity follows the phase transition due to the resulting changing inter-dot distances. The changes in PL intensity accompany a redshift in the emission spectrum, which agrees with the Förster resonance energy transfer (FRET) theory. The results are essential for a fundamental understanding of the impact of strain on the performance of flexible devices based on QD films, such as wearable electronics and next-generation solar cells on flexible substrates.

Clinical characteristics of children with omicron SARS-CoV-2 infection in Changchun, China from march to april 2022: A retrospective study.

Background: Recently, there was an outbreak in China of the Omicron (B.1.1.529) variant, the corresponding clinical characteristics of Chinese children with the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were then reviewed and summarized retrospectively. Methods: From March to April 2022, a total of 134 children infected with the Omicron variant were included in the study. Data such as sex, age, clinical symptoms, laboratory examinations, and imaging features were collected for further analyses. Results: Half of the children were male and the median age was 5.67 years. The most SARS-CoV-2 Omicron variant was identified in mild (122, 91%), and the most three frequent symptoms were as cough (108, 80.6%), fever (75, 56%), and sore throat (38, 28.4%). Among age groups, no significant difference was observed in the distribution of symptoms, and no statistical difference was found in different clinical types among sex or age groups. Laboratory examinations revealed that white blood cells, neutrophils, and hemoglobin decreased; and monocytes, C-reactive protein (CRP), and aspartate aminotransferase (AST) increased. Further analyses showed that neutrophils, hemoglobin, CRP, and AST exhibited significant differences among age groups. Radiological abnormalities were found in nine cases, with small patchy high-density shadows. Of the 76 cured cases discharged from the hospital, the median hospital stay was 13 days (mean, 12 days). Conclusions: In China, most children with Omicron SARS-CoV-2 infection have mild presentation. The findings of this study may help other districts improve the management of children with Omicron SARS-CoV-2 infection in China.

Effects of a fixed nurse team in the orthopaedic surgery operating room on work efficiency and patient outcomes: a propensity score-matched historically controlled study.

BACKGROUND: The work value of operating room (OR) nurses is directly reflected in nursing quality. However, evaluating the work value of these nurses has not been sufficiently investigated. This study evaluated the effects of a fixed nurse team (FNT) in an orthopaedic surgery OR on work efficiency and patient outcomes. METHODS: A propensity score-matched historically controlled study conducted from 1 July 2015 to 30 June 2018 was used to investigate the difference in nursing quality between an FNT period and a non-FNT period in the orthopaedic surgery OR at a tertiary care hospital in China. The primary outcome was surgical site infections (SSIs) during in-hospital visits, and as a secondary outcome, other nursing-sensitive quality indicators were assessed with historically controlled data. A multifactor logistic regression model was constructed to examine the primary outcome differences between the FNT and non-FNT periods before and after propensity score matching. RESULTS: In total, 5365 patients and 33 nurses were included in the final analysis. The overall SSI rate was 2.1% (110/5365; the non-FNT period 2.6% [64/2474], the FNT period 1.6% [46/2891]). A lower incidence of SSIs in patients (odds ratio 0.57, 95% CI 0.36 to 0.88, P=0.013), a lower turnover time of the surgical procedure (odds ratio 0.653, 95% CI 0.505 to 0.844, P<0.001), and improvement in surgeon satisfaction (odds ratio 1.543, 95% CI 1.039 to 2.292, P=0.031), were associated with the FNT period compared with the non-FNT period. However, we did not find significant differences between the FNT period and the non-FNT period in terms of the other indicators. CONCLUSIONS: The presence of an FNT in an OR reduces the incidence of SSIs in surgical patients and the turnover time of surgical procedures and improves surgeon satisfaction. Further implementation of an advanced-practice nurse model with nurse specialists is encouraged.

In Situ Growth of All-Inorganic Perovskite Single Crystal Arrays on Electron Transport Layer.

Directly growing perovskite single crystals on charge carrier transport layers will unravel a promising route for the development of emerging optoelectronic devices. Herein, in situ growth of high-quality all-inorganic perovskite (CsPbBr3) single crystal arrays (PeSCAs) on cubic zinc oxide (c-ZnO) is reported, which is used as an inorganic electron transport layer in optoelectronic devices, via a facile spin-coating method. The PeSCAs consist of rectangular thin microplatelets of 6-10 µm in length and 2-3 µm in width. The deposited c-ZnO enables the formation of phase-pure and highly crystallized cubic perovskites via an epitaxial lattice coherence of (100)CsPbBr3∥(100)c-ZnO, which is further confirmed by grazing incidence wide-angle X-ray scattering. The PeSCAs demonstrate a significant structural stability of 26 days with a 9 days excellent photoluminescence stability in ambient environment, which is much superior to the perovskite nanocrystals (PeNCs). The high crystallinity of the PeSCAs allows for a lower density of trap states, longer carrier lifetimes, and narrower energetic disorder for excitons, which leads to a faster diffusion rate than PeNCs. These results unravel the possibility of creating the interface toward c-ZnO heterogeneous layer, which is a major step for the realization of a better integration of perovskites and charge carrier transport layers.

Facile preparation of a collagen-graphene oxide composite: A sensitive and robust electrochemical aptasensor for determining dopamine in biological samples.

A sensitive and robust electrochemical aptasensor for determining dopamine (DA) was developed using a grass carp skin collagen-graphene oxide (GCSC-GO) composite as a transducer and a label-free aptamer as a biological recognition element for the first time. In order to fabricate this sensor, the GCSC-GO composite was firstly prepared by ultra-sonication method and characterized by atomic force microscope, infrared spectroscopy, Raman spectroscopy, and electrochemical impedance spectroscopy. Subsequently, a label-free DA-binding aptamer was immobilized through strong interaction between collagen and aptamer. The fabricated electrochemical aptasensor was used to determine DA by differential pulse voltammetry. The results indicated that the peak current changes of the developed aptasensor was linear relationship with the DA concentrations from 1 to 1000 nM, and the detection limit was 0.75 nM (S/N = 3). Moreover, the fabricated aptasensor showed high selectivity for DA. More importantly, the obtained aptasensor exhibited satisfactory recovery toward DA in human serum specimens with excellent stability.