Tuneable Efficient White Emission of Sb3+/Mn2+ Co-Doped Lead-Free Perovskites for Single-Component White Light-Emitting Diodes.

Inorganic lead-free perovskite nanocrystals (NCs) with broadband self-trapped exciton (STEs) emission and low toxicity have shown enormous application prospects in the field of display and lighting. However, white light-emitting diodes (WLEDs) based on a single-component material with high photoluminescence quantum yield (PLQY) remain challenging. Here, we demonstrate a novel codoping strategy by introducing Sb3+/Mn2+ ions to achieve the tuneable dual emission in lead-free perovskite Cs3InCl6 NCs. The PLQY increases to 59.64% after doping with Sb3+. The codoped Cs3InCl6 NCs exhibit efficient white light emission due to the energy transfer channel from STEs to Mn2+ ions with PLQY of 51.38%. Density functional theory (DFT) calculations have been used to verify deeply the effects of Sb3+/Mn2+ doping. WLEDs based on Sb3+/Mn2+-codoped Cs3InCl6 NCs are explored with color rendering index of 85.5 and color coordinate of (0.398, 0.445), which have been successfully applied as photodetector lighting sources. This work provides a new perspective for designing novel lead-free perovskites to achieve single-component WLEDs.

Source apportionment of soil PTE in a northern industrial county using PMF model: Partitioning strategies and uncertainty analysis.

Positive matrix factorization (PMF) has commonly been applied for source apportionment of potentially toxic elements (PTE) in agricultural soil, however, spatial heterogeneity of PTE significantly undermines the accuracy and reliability of PMF results. In this study, a representative industrial-agricultural hub in North China (Xuanhua district, Zhangjiakou City) was selected as the research subject, multiple partition processing (PP) strategies and uncertainty analyses were integrated to advance the PMF modeling and associated algorithm mechanisms were comparatively discussed. Specifically, we adopted three methods to split the research area into several subzones according to industrial density (PP-1), population density (PP-2), and the ecological risk index (PP-3) respectively, to rectify the spatial bias phenomenon of PTE concentrations and to achieve a more interpretable result. Our results indicated that the obvious enrichment of Cd, Pb, and Zn was found in the agricultural soil, with Hg and Cd accounted for 83.49% of the overall potential ecological risk. Combining proper PP with PMF can significantly improve the modelling accuracy. Uncertainty analysis showed that interval ratios of tracer species (Cd, Pb, Hg, and Zn) calculated by PP-3 were consistently lower than that of PP-1 and PP-2, indicating that PP-3 coupled PMF can afford the optimal modeling results. It suggested that natural sources, fertilizers and pesticides, atmosphere deposition, mining, and smelting were recognized as the major contributor for the soil PTE contamination. The contribution of anthropogenic activities, specifically fertilizers and pesticides, and atmosphere deposition, increased by 1.64% and 5.91% compared to PMF results. These findings demonstrate that integration of proper partitioning processing into PMF can effectively improve the accuracy of the model even at the case of soil PTE contamination with high heterogeneity, offering support to subsequently implement directional control strategies.

Aquatic photolysis of high-risk fluorinated liquid crystal monomers: Kinetics, toxicity evaluation, and mechanisms.

Despite the frequent detection of fluorinated liquid-crystal monomers (FLCMs) in the environment, the level of understanding of their fate, toxicity, and transformation remains insufficient. Herein, we investigated the degradation kinetics and mechanism of an FLCM (4-cyano-3-fluorophenyl 4-ethylbenzoate, CEB-F) under ultraviolet (UV) photolysis in aquatic environment. Our findings demonstrated that the UV photolysis of CEB-F followed first-order kinetics. Photodegradation products were identified using liquid chromatography with mass spectrometry, and detailed reaction pathways were proposed. It is postulated that through the attack of reactive oxygen species, hydroxylation, and CO/C-F bond cleavage, CEB-F gradually degraded into small molecular compounds, releasing fluorine ions. Acute immobilization tests with Daphnia magna (D. magna) revealed significant acute toxicity of CEB-F, with LC50 values ranging from 1.023 to 0.0536 µM over 24 to 96 h, emphasizing the potential high risk of FLCMs in aquatic ecosystems if inadvertently discharged. Interestingly, we found that the toxicity of CEB-F photolysis reaction solutions was effectively reduced. Through catalase and acetylcholinesterase activities analysis along with molecular docking simulation, we proposed differences in the underlying toxicity mechanisms of CEB-F and its photolysis products to D. magna. These findings highlight the potential harmful effects of FLCMs on aquatic ecosystems and enrich our understanding of the photolysis behavior of FLCMs.

Age-dependent changes in the gut microbiota and serum metabolome correlate with renal function and human aging.

Human aging is invariably accompanied by a decline in renal function, a process potentially exacerbated by uremic toxins originating from gut microbes. Based on a registered household Chinese Guangxi longevity cohort (n = 151), we conducted comprehensive profiling of the gut microbiota and serum metabolome of individuals from 22 to 111 years of age and validated the findings in two independent East Asian aging cohorts (Japan aging cohort n = 330, Yunnan aging cohort n = 80), identifying unique age-dependent differences in the microbiota and serum metabolome. We discovered that the influence of the gut microbiota on serum metabolites intensifies with advancing age. Furthermore, mediation analyses unveiled putative causal relationships between the gut microbiota (Escherichia coli, Odoribacter splanchnicus, and Desulfovibrio piger) and serum metabolite markers related to impaired renal function (p-cresol, N-phenylacetylglutamine, 2-oxindole, and 4-aminohippuric acid) and aging. The fecal microbiota transplantation experiment demonstrated that the feces of elderly individuals could influence markers related to impaired renal function in the serum. Our findings reveal novel links between age-dependent alterations in the gut microbiota and serum metabolite markers of impaired renal function, providing novel insights into the effects of microbiota-metabolite interplay on renal function and healthy aging.

Cleaner production of Chinese cabbage by intercropping from Cd contaminated soil: Effects of hyperaccumulator variety and planting strip width.

The utilization of Cd-contaminated soil in vegetable crop production can lighten the food crisis and improve the soil environmental resilience. Intercropping is a reliable technology in safety production from contaminated soil. A field-scale experiment was carried out to unravel how plant species and pattern affect the growth and Cd uptake of Chinese cabbage from Cd contaminated land. Among all the intercropping systems designed in this study, one row of Chinese cabbage intercropping with one row of Solanum nigrum L. is the best planting mode (high yields (2.78 kg/m2) and low Cd accumulation (0.02 mg/kg) of Chinese cabbage). Combined with the in-depth joint analysis of diverse soil physicochemical features (soil nutrient characteristics and microbial community structure), biomass yield and quality, and soil microbiological properties, we elaborated that two measures (screening hyperaccumulation types and controlling planting strip width) were the major factors in determining the growth of the aboveground and underground parts of Chinese cabbage respectively, thus directly regulating the application effectiveness of intercropping technology. The intertwined mechanisms (interspecific and intraspecific relationship) of different intercropping systems are summarized, which include better utilization of space, light and other resources in the aboveground part, bioavailability of nutrient, drive of soil bacteria and alleviated soil Cd stress in the underground part, etc. Our research outputs indicate the effectiveness and feasibility of intercropping can be improved by optimizing the streamline configuration and plant mode, which provide theory of reference and practical evidence for warranting the food safety and agricultural soil remediation simultaneously.

Enriched-Bromine Surface State for Stable Sky-Blue Spectrum Perovskite QLEDs With an EQE of 14.6.

Halogen vacancies are of great concern in blue-emitting perovskite quantum-dot light-emitting diodes because they affect their efficiency and spectral shift. Here, an enriched-bromine surface state is realized using a facile strategy that employs a PbBr2 stock solution for anion exchange based on Cd-doped perovskite quantum dots. It is found that the doped Cd ions are expected to reduce the formation energy of halogen vacancies filled by the external bromine ions, and the excess free bromine ions in solution are enriched in the surface by anchoring with halogen vacancies as sites, accompanied with the shedding of surface long-chain ligands during the anion exchange process, resulting in a Br-rich and "neat" surface. Moreover, the surface state exhibits good passivation of the surface defects of the controlled perovskite QDs and simultaneously increases the exciton binding energy, leading to excellent optical properties and stability. Finally, the sky-blue emitting perovskite quantum-dot light-emitting diodes (QLEDs) (490 nm) are conducted with a record external quantum efficiency of 14.6% and current efficiency of 19.9 cd A-1 . Meanwhile, the electroluminescence spectra exhibit great stability with negligible shifts under a constant operating voltage from 3 to 7 V. This strategy paves the way for improving the efficiency and stability of perovskite QLEDs.

A combined management scheme to simultaneously mitigate As and Cd concentrations in rice cultivated in contaminated paddy soil.

Paddy soils in southern China are heavily co-polluted by arsenic (As) and cadmium (Cd). The accumulation of these contaminants in rice grains may pose a high health risk. We evaluated the impact of adjusted water management practice (i.e., conventional irrigation and aerobic treatment after heading stage) and the application of two immobilization agents (i.e., CaO and Fe2O3) on the accumulation of As and Cd in rice grains of three rice varieties (i.e., Jinyou-463, Jinyou-268, and Mabayouzhan). The different schemes were tested via conducting a field experiment in paddy soil in Shaoguan, Guangdong Province, China. The results showed that the combined scheme (selecting Jinyou-268, aerobic water management after the heading stage, and 0.09% CaO and 0.5% Fe2O3 amendments) exhibited the best performance in the reduction of As and Cd accumulation in rice grains. This combined scheme decreased the grain As concentration by 26.19% and maintained the Cd at a low level (0.056 mg/kg) as compared to the use of local conventional irrigation patterns. Moreover, health risk assessment demonstrated that by applying the optimal scheme, neither As nor Cd content in rice had carcinogenic risk. However, the grain As remains at a high non-carcinogenic risk. We suggest that future field study design should fully incorporate the uncertainty of the natural environment to make the research conclusions more feasible for popularization and utilization. This study demonstrated an approach of utilizing the synergy effects of various measures for safe rice production in fields subjected to As and Cd contaminations.

Suppressing ion migration of CsPbBrxI3-xnanocrystals by Nickel doping and the application in high-efficiency WLEDs.

All inorganic perovskite nanocrystals CsPbX3(X = Cl, Br, I) are the great potential candidates for the application of high-performance light emitting diodes (LED) due to their high Photoluminescence Quantum Yield (PLQY), high defect tolerance, narrow full-width half-maximum and tunable wavelength of 410-700 nm. However, the application of red-emitting (630-650 nm) CsPbBrxI3-xnanocrystals are perplexed by phase segregation due to the composition of mixed halides and the difference in halide ion mobility. Herein, we provide an effective strategy to suppressing the migration of Br/I ions through Ni2+doping via a facile Hot-Injection method and the PLQY was improved as well. DFT calculations show that the introduction of Ni2+causes a slight contraction of the host crystal structure, which improves the bond energy between Pb and halides and reduces the level of surface defects. Therefore, the phase stability is improved by Ni2+doping because the phase segregation caused by ion migration in the mixed phase is effectively inhibited. Meanwhile, the non-radiative recombination in the exciton transition process is reduced and the PLQY is improved. What's more, benefiting from the suppressed ion migration and enhanced PLQY, we combine the Ni2+-doped CsPbBrxI3-xnanocrystals with different Br/I ratios and YAG: Ce3+phosphors as color conversion layers to fabricate high efficiency WLED. When the ratio of Br/I is 9:11, WLED has a color coordinate of (0.3621, 0.3458), the color temperature of 4336 K and presents a high luminous efficiency of 113.20 lm W-1, color rendering index of 94.9 under the driving current of 20 mA and exhibits excellent stability, which shows great potential in the application of LED.

Direct deposition of Sn-doped CsPbBr3 perovskite for efficient solar cell application.

All inorganic carbon-based planar perovskites, particularly CsPbBr3, have attracted considerable attention due to their excellent stability against oxygen, moisture, and heat for photovoltaic utilization. However, the power conversion efficiency of carbon-based planar CsPbBr3 perovskite solar cells is mostly low, primarily because of the inferior film quality with undesirable crystallization and narrow light absorbance ranges. Herein, we develop a novel direct deposition approach combined with Sn doping to achieve highly efficient and stable carbon-based Sn-doped CsPbBr3 perovskite solar cells. Mass-scale Sn ion-doped CsPbBr3 perovskite powder was effectively synthesized and characterized via a facile strategy by adding hydrohalic acid in the CsBr, PbBr2 and SnBr2 precursor in a dimethyl sulfoxide solution. Moreover, using the as-synthesized CsPbBr3 and Sn-doped CsPbBr3 perovskite powder, PSCs were obtained via effective direct thermal evaporation. A smooth, constant and pinhole-free perovskite film was achieved with a configuration of FTO/TiO2/Sn:CsPbBr3/carbon. PSCs based on Sn:CsPbBr3 as an absorber and carbon as the HTM achieved an impressive power conversion efficiency of 8.95% compared to 6.87% for undoped CsPbBr3; moreover, it displayed admirable stability in an open-air atmosphere for an operational period of about 720 h without a noticeable negative result. The introduction of the Sn ion may advance the interface extraction of charge between the electric transport layer to the absorber layer and absorber to the carbon electrode. Accordingly, the Sn ion doping on CsPbBr3 during the synthesis phase and the direct evaporation paves a novel approach for intended photovoltaic applications.

Safety, tolerability, and immunogenicity of 7-valent pneumococcal conjugate vaccine in older infants and young children in China who are naive to pneumococcal vaccination: Results of a phase 4 open-label trial.

BACKGROUND: This postlicensure study was conducted to assess immunogenicity and safety of PCV7 catch-up regimens in previously unvaccinated older infants and young children in China. METHODS: Healthy children 121 days to <72 months were grouped by age and immunized with 1 of 4 PCV7 dosing regimens. Serotype-specific IgG geometric mean concentrations (GMCs) and percentage of subjects with IgG≥0.35µg/mL were assessed before vaccination and 1 and 12 months postvaccination. The incidence of clinically important adverse events (AEs) and serious AEs (SAEs), AEs leading to study withdrawal, and protocol-related AEs were assessed throughout the study. RESULTS: Prevaccination serotype-specific GMCs were generally low in subjects <24 months; the majority of children 24 to <72 months had IgG concentrations ≥0.35 µg/mL. One month postvaccination, GMCs were similar across groups for the 7 PCV serotypes, ranging from 3.95 to 13.02 µg/mL; the highest antibody levels were observed for serotype 14. Regardless of dosing regimen, >90% of subjects had IgG≥0.35 µg/mL for each PCV serotype. At 12-month follow-up, IgG GMCs ranged from 0.65 to 5.19, and all remained above prevaccination IgG GMC; >70% of subjects had IgG≥0.35 µg/mL. Older children generally had the most robust immune response both at 1 month postvaccination and during 12-month follow-up. PCV7 was well tolerated. Pyrexia, which was mild to moderate in severity, was the most common AE. Two subjects reported SAEs (n=4), and there was 1 study withdrawal; none of these were considered treatment related. CONCLUSION: In China, PCV7 catch-up vaccinations given to older infants and young children naive to pneumococcal vaccines resulted in a robust immune response to all serotypes; this response persisted after 1 year. PCV7 was well tolerated in Chinese infants and children.

Effect of compressed CO2 on the chloroperoxidase catalyzed halogenation of 1,3-dihydroxybenzene in reverse micelles.

The effect of compressed CO2 on the specific activity of chloroperoxidase (CPO) to catalyze the chlorination of 1,3-dihydroxybenzene in cetyltrimethylammonium chloride (CTAC)/H2O/octane/pentanol reverse micellar solution was studied. The results show that the specific activity of the enzyme can be enhanced significantly by compressed CO2, and the specific activity can be tuned continuously by changing pressure. The mechanism for the specific activity enhancement of the enzyme by CO2 was also studied. We believe that compressed CO2 can be utilized to tune some other enzyme catalytic reactions in different reverse micellar systems with potential advantages.

Synthesis of cross-linked enzyme aggregates (CLEAs) in CO2-expanded micellar solutions.

A new method to prepare the cross-linked enzyme aggregates (CLEAs) was developed. Through cross-linking the enzyme (Trypsin) aggregates, which was precipitated from the CO2-expanded reverse micellar solutions, dendritic CLEAs were obtained. The sizes of the CLEAs prepared by this new method were nanometer order of magnitudes and could be tuned by changing the water-to-surfactant ratio (w0) and the concentration of enzyme in the reverse micellar solution. The diameter of CLEAs increased with increasing w0 value of reverse micelles and the concentration of Trypsin. The activity of CLEAs obtained by this method is improved in contrast to those obtained by the conventional method. This method has some advantages in applications and can be easily applied to the synthesis of other cross-linked enzyme aggregates.

Ultrasound-induced capping of polystyrene on TiO2 nanoparticles by precipitation with compressed CO2 as antisolvent.

In this work, a route for the synthesis of inorganic/polymer core/shell composite nanoparticles was proposed, which can be called the antisolvent-ultrasound method. Compressed CO2 was used as antisolvent to precipitate the polymer from its solution dispersed with inorganic nanoparticles, during which ultrasonic irradiation was used to induce the coating of precipitated polymers on the surfaces of the inorganic nanoparticles. TiO2/polystyrene (PS) core/shell nanocomposites have been successfully prepared using this method. The transmission electronic micrographs (TEM) of the obtained nanocomposites show that the TiO2 nanoparticles are coated by the PS shells, of which the thickness can be tuned by the pressure of CO2. The phase structure, absorption properties, and thermal stability of the composite were characterized by X-ray diffraction (XRD), UV-vis spectra, and thermogravimetry, respectively. The results of X-ray photoelectron spectra (XPS) indicate the formation of a strong interaction between PS and TiO2 nanoparticles in the resultant products. This method has some potential advantages for applications and may be easily applied to the preparation of a range of inorganic/polymer core/shell composite nanoparticles.

Fabrication of flowerlike polymer superstructures using polymer/zeolite composites prepared with supercritical CO2.

We report a route to the fabrication of unique flowerlike polymer superstructures with uniform petals at the nanoscale. In this method, polymer/zeolite composite is first prepared by loading corresponding monomer and initiator into the channels of the host zeolite with the aid of supercritical (SC) CO2, followed by thermal polymerization of monomers in the channels of the zeolite. The resultant polymer/zeolite composite is then treated with HF aqueous solution to allow the self-aggregation of the polymer and the inorganic components to form the polymeric layers and inorganic layers. Unique microscale flowerlike polymer superstructures are obtained after further treatment with HF aqueous solution. Different techniques, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry (TG), have been used to characterize the microflowers.

Compressed CO2-enhanced solubilization of 1-butyl-3-methylimidazolium tetrafluoroborate in reverse micelles of Triton X-100.

We carried out the first study about the effect of a compressed gas on the properties of reverse micellar solutions with ionic liquid (IL) polar cores. And the properties of compressed CO2/cyclohexane/1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4])/Triton X-100 (TX-100) system were investigated at 288.2, 293.2, 298.2, 308.2 K and different pressures by using phase behavior measurement, small-angle x-ray scattering, and UV-Vis techniques. The concentration of the surfactant in the solution was 0.3 mol/l (M). It was found that compressed CO2 could enhance solubilization of the IL in the reverse micelles considerably at suitable pressures, and formation of the reverse micelles could be controlled easily by pressure. Increase of CO2 pressure resulted in decrease of the micellar sizes at fixed [bmim][BF4]-to-surfactant molar ratios (w), and the size of the reverse micelles increased with the increase of w values. The polarity of the IL cores increased continuously with increasing w value.

Enhancement of the solubilization capacity of water in Triton X-100/cyclohexane/water system by compressed gases.

The effect of compressed CO2 and ethylene on the properties of Triton X-100/cyclohexane/water systems was studied at different temperatures and pressures. Surprisingly, it was discovered that the compressed gases had the functions of co-surfactants. At suitable pressures, the water-to-surfactant molar ratio (W0) was enhanced significantly by the dissolution of the gas in the solution. The microenvironment in the reverse micelles was investigated by UV-visible spectroscopy by using methyl orange (MO) as a probe. The influence of n-hexane, Na2CO3, NaHCO3, H2C2O4, and CaCl2 at various concentrations on the solubilization of water in the absence of compressed gases was also investigated in order to obtain some information about the mechanism of the interesting phenomenon. This new route to stabilize reverse micelles may have potential applications to other similar systems. Moreover, the results of this work provide some useful information to get insight into the mechanism of co-surfactants, because a conventional co-surfactant usually contains both polar group and hydrocarbon chain, and it is very difficult to clarify the functions these two groups, while the gases used in this work are small nonpolar molecules, which solely have the function of the hydrocarbon chain in a co-surfactant.