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The composite Ag@1 was obtained in the synthesis process of porous In-MOF 1 with addition of AgNO3,viathein situreduction of Ag(i) to Ag NPs. MOF 1 and Ag@1 had great gas selective sorption and CO2catalytic conversion capacity.

Background Stroke is a common and frequently-occurring disease in elderly people. It has the characteristics of high morbidity, high mortality, high recurrence rate and high disability rate. Most stroke risk studies are based on pathophysiology, however psychosocial factors such as diet quality are often understudied. The aim of this study was to assess stroke risk in urban community residents in Tianjin and investigate the impact of diet quality on stroke risk. Methods Using a cross-sectional, multicenter study, recruit people aged 60 to 80 in Tianjin. Dietary intake data were obtainedthrough a validated food frequencyquestionnaire, which were used to calculate Alternate Healthy Eating Index-2010 (AHEI-2010) and to analyzeits association with sociodemographic, stroke risk factors and health marker variables. Results A total of 1068 participants were recruited, including 300 low-risk groups and 768 high-risk groups. Compared with the low-risk group (62.75 ± 3.59), the AHEI-2010 mean score of the high-risk group (56.83 ± 6.54) was significantly lower. The top three most common risk factors among participants were dyslipidemia (80.3%), hypertension (60.6%), and physical inactivity (58.2%). Multiple logistic regression showed that diet quality was independently and significantly associated with stroke risk (OR = 0.765; 95% CI: 0.690–0.848, p

The discharge of excessive metal ions and anions into water bodies leads to the serious pollution of water and environment, which in turn has a certain impact on industry, agriculture, and human life. Because of the unique advantages of luminescent metal-organic frameworks (LMOFs), they have been successfully explored as various fluorescent probes to quickly and effectively detect these pollutants. This perspective not only introduces the design strategy and classification of LMOFs, especially the construction methods of water-stable LMOFs, but also reports the latest progresses in some LMOFs between 2016 and 2020 as well as expounds the mechanisms of LMOFs for detecting anions and cations. Moreover, the luminescence properties of LMOFs are related to the selection of metal ions, the structure of organic ligands, the pore size, and the interaction of guest molecules. Finally, the further development of LMOFs is summarized and prospected in this field.

ObjectiveAmbient air pollution is associated with ischaemic stroke incidence. However, most of the previous studies used stroke-related hospital admission rather than stroke onset itself. This study aimed to evaluate the relationship between ambient air pollutant exposures and acute ischaemic stroke based on the timing of symptom onset.MethodsA time-stratified, case-crossover analysis was performed among 520 patients who had ischaemic stroke admitted to the Second Hospital of Tianjin Medical University (Tianjin, China) between 1 April 2018 and 31 March 2019 (365 days). Daily air pollutant concentrations of particulate matter with aerodynamic diameter 2.5 µm, particulate matter with aerodynamic diameter 10 µm (PM10), sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone were obtained from fixed-site monitoring stations. We used conditional logistic regression to estimate OR and 95% CI corresponding to an increase in IQR of each air pollutant after adjusting for the effects of temperature and relative humidity.ResultsOverall, a higher risk of ischaemic stroke was found between April and September. During this period PM10 was associated with an increased risk of ischaemic stroke (1-day lag: OR=1.49, 95% CI 1.09 to 2.02; 3-day mean: OR=1.58, 95% CI 1.09 to 2.29) among patients between 34 and 70 years old. Positive associations were also observed between PM10 (1-day lag: OR=1.51, 95% CI 1.10 to 2.07; 3-day mean: OR=1.57, 95% CI 1.08 to 2.29), ozone (1-day lag: OR=1.83, 95% CI 1.16 to 2.87; 3-day mean: OR=1.90, 95% CI 1.06 to 3.42) and ischaemic stroke occurrence among those with hyperlipidaemia.ConclusionOur results suggest that air pollution is associated with a higher risk of ischaemic stroke in younger people or people with hyperlipidemia. These findings still need to be further investigated.

Purpose The effects of meteorological parameters on stroke occurrence remain debated. The aim of the study was to assess the association between meteorological parameters and ischemic stroke onset in cold seasons in Tianjin. Patients and Methods Patients with acute ischemic stroke (946) were identified by standard sampling from one stroke unit in the Second Hospital of Tianjin Medical University, Tianjin, China, from 10/1/2014 to 4/30/2019. Generalized linear Poisson regression models were used to explore the effect of meteorological parameters (air temperature, barometric pressure, and relative humidity) on daily ischemic stroke onset after adjusting for air pollutants, day of week, and public holiday. Results The results showed that ischemic stroke onset was positively associated with the diurnal variation of temperature (β coefficient: 0.020, 95% CI [0.001, 0.038] p

Electroluminescence (EL) images with absolute photon emissions from Cu(In, Ga)Se2 (CIGS) solar cells were obtained under different forward current injections, with the spatially distributed EL emission becoming non-uniform as the current density gradually increases. A distributed two-diode electrical three-dimensional model was established which simulated the dark current density-voltage curves and the absolute EL images of the CIGS solar cells very well. Then, the resistive effects were analyzed using this model and simulation results show that the sheet resistance of the transparent conductive oxide (TCO) layer dominates the non-uniform distribution of the EL emission in the studied CIGS thin-film solar cells. The effect of the sheet resistance of the TCO and the series resistance of the micro-diode on the EL variations is found to become obvious under high-current-injection conditions, whereas the effect of shunt resistance of the micro-diode on the EL variations becomes more obvious under low-resistance value or low-current-injection conditions.

As an emerging cancer treatment strategy, photothermal therapy (PTT) is precise, controllable, minimally invasive, low cost and less toxic side effects, thus photothermal transduction agents have been extensively investigated in recent years. Noble metal nanomaterials with unique localized surface plasmon resonance (LSPR) effects are particularly suitable as photothermal transduction agent, but the currently developed precious noble metal nano photothermal transduction agents face serious problems such as complex synthesis process, poor photothermal performance and high biotoxicity. Moreover, the large amount of reactive oxygen species (ROS) produced during PTT treatment could cause irreversible damage to the healthy tissues surrounding the tumor. In this work, we deposited platinum (Pt) on the tips of gold nanorods (AuNRs) to form dumbbell-shaped Au-Pt bimetallic nanorods (AuPtNRs), and functionalized AuPtNRs with biocompatible polydopamine (PDA) to obtain AuPt@PDA. With 808 nm laser irradiation, the prepared AuPt@PDA exhibited excellent photothermal stability, and its photothermal conversion efficiency (PCE) reached 81.78%, which was significantly higher than that of AuNRs (52.32%) and AuPtNRs (78.76%). With low cytotoxicity, AuPt@PDA decreased cell viability from 91.12% to 39.36% after PTT on cancer cells in vitro, while significantly reducing intracellular ROS levels generated by heat stress. Therefore, the excellent photothermal properties, high cancer cell killing and ROS scavenging activity of AuPt@PDA in PTT could be an ideal candidate for improving therapeutic efficacy while reducing the risk of toxic side effects due to heat stress-induced ROS formation.

Superstrate ITO/CdS/Sb2Se3/Au thin-film solar cells were fabricated with a CdS film produced by a radio-frequency (RF) magnetron-sputtering method as the buffer layer. The effect of the CdS layer thickness (70–120 nm) on the properties of Sb2Se3 thin films and the performance of the solar cells was investigated. The optimal CdS thickness was 90 nm, which led to the best power conversion efficiency of 5.91%; to the best of our knowledge, this is the highest efficiency for Sb2Se3 solar cells with a sputtered CdS buffer layer to date. X-ray diffraction and scanning electron microscope results indicated that the Sb2Se3 films grown on 90-nm-thick CdS layers had the optimal grain orientation and the best morphology. The current–voltage (J–V) and admittance results indicated that the Sb2Se3 cell with a 90-nm-thick CdS layer had the lowest saturation current and the smallest defect densities. Moreover, temperature- and light intensity-dependent open-circuit (Voc) measurements revealed that the carrier recombination rates at the CdS/Sb2Se3 interface, space-charge region (SCR), and quasi-neutral region (QNR) all achieved the smallest value for the Sb2Se3 cells with a 90-nm CdS buffer layer. These data account for the optimal cell performance and offer new research directions for solving challenges of chemical bath deposition of CdS in Sb2Se3 solar cells.

Electronic transport mechanisms in Sb2Se3 thin-film solar cells were investigated using temperature-dependent current-voltage (J-V) measurements. Sb2Se3 thin films were deposited via the vapor transporting deposition method using a double-temperature-zone tubular furnace system, and comparative studies were performed for Sb2Se3 films formed on substrates located at three different positions away from the furnace center. The device efficiency varied from 3.83 to 6.24%. First, structural properties obtained by X-ray diffraction, Raman and scanning electron microscopy measurements verified the optimal Sb2Se3 film quality for the cell with the highest efficiency. Then, temperature-dependent saturation current and open-circuit voltage (Voc) measurements revealed that the dominant carrier recombination occurred in the CdS/Sb2Se3 interface region, which possibly influenced the Voc for all cells: the highest Voc for the optimal Sb2Se3 cell was at least partly due to it having the lowest CdS/Sb2Se3 interface recombination rate. Finally, the reverse bias current relationship revealed that non-ohmic shunt current (space-charge-limited current, SCLC) plays an important role in affecting the performance of solar cells, as lower-efficiency cells had higher non-ohmic shunt current.

Hybrid organic–inorganic metal halide perovskites are currently arousing enthusiasm and stimulating huge activity across several fields of optoelectronics due to their outstanding properties. In this study, we present the incoherent random lasing (RL) emissions from CH3NH3PbBr3 perovskite thin films on both planar fluorine-doped tin oxide (FTO) substrates and patterned sapphire substrates (PSSs). A detailed examination of the spectral evolution indicates that inelastic exciton–exciton scattering called P-emission is the most plausible mechanism accounting for the lasing emissions. The RL threshold of the perovskite films on PSSs is found to be effectively reduced by more than one order of magnitude from 2.55 to 0.15 μJ per pulse compared to that on FTO substrates. The giant threshold reduction is ascribed to the enhanced random scattering of light and the photon recycling induced by the multireflection processes at the perovskite/PSS interface, which increases the likelihood that the inoperative random rays will re-enter the possible optical loops formed among the perovskite particles, resulting in considerable optical resonance enhancement. The simulation results reveal that the light extraction efficiency on the top facet of the perovskites is significantly increased by approximately 155% by utilizing the PSS instead of the FTO substrate. Moreover, the first direct experimental observation of the multireflection phenomenon of light, as well as the dynamic processes of photon propagation in the composite PSS structure, is presented by Kerr-gate-based time-resolved photoluminescence. Our results provide an effective strategy to achieve high-performance perovskite random lasers and novel light-emitting devices for speckle-free full-field imaging and solid-state lighting applications, by introducing ingeniously designed periodic nano-/microscale optical structures.

Sb2Se3 thin films prepared by vapor transport deposition (VTD) method have been treated by post annealing process at 200 °C in vacuum condition for 1 h, and the comparative studies between the post annealing treatment (PAT) and without the treatment were carried out. The device efficiency was improved from 4.89% to 5.72% by PAT via the augment of open-circuit voltage and fill factor. Electrical properties from dark J-V and C-V measurements, structural properties from X-ray diffraction, Raman and scanning electron microscope measurements, defect properties from admittance measurements have been compared for the two cell samples. The Sb2Se3 cell sample with PAT was found to own less parallel current pathways, larger built-in voltage, better crystalline and lower defects densities, which may account for the efficiency enhancement.

The defect properties of

Organometallic halide perovskites have been demonstrated to be very promising for nonlinear optics and practical frequency upconversion devices in integrated photonics. In this work, high quality o...

Accurate estimation of green aboveground biomass is important for sustainable use of grassland resources in arid and semiarid grasslands. Nevertheless, it is difficult to achieve spatial upscaling of green aboveground biomass estimation using traditional spatial upscaling methods in arid and semiarid grasslands due to its inherent heterogeneity. In the study, a new spatial upscaling algorithm was proposed to estimate green aboveground biomass in the desert steppe of Inner Mongolia. The algorithm was successfully employed for spatial upscaling of green aboveground biomass estimation from MOD13Q1 NDVI (fine resolution) to MOD13A2 NDVI (coarse resolution) based on field measurements in the desert steppe. Results showed that, the correlation between distributed green aboveground biomass (obtained from fine resolution) and lumped green aboveground biomass (obtained from coarse resolution) was improved, and root mean squared error and relative error decreased after upscaling. Statistical analyses performing on the slopes and intercepts of the fitted lines between distributed green aboveground biomass and lumped green aboveground biomass demonstrated that, there was no significant difference (P > 0.05) between the fitted line and the 1:1 line after upscaling, and there was significant difference (P

We have developed a rapid and ultrasensitive surface-enhanced Raman scattering (SERS) assay for Cu2+ detection using the multiple antibiotic resistance regulator (MarR) as specific bridging molecules in a SERS hot-spot model. In the assay, Cu2+ induces formation of MarR tetramers, which provide Au nanoparticle (NP)–AuNP bridges, resulting in the formation of SERS hot spots. 4-Mercaptobenzoic acid (4-MBA) was used as a Raman reporter. The addition of Cu2+ increased the Raman intensity of 4-MBA. Use of a dual hot-spot signal-amplification strategy based on AuNP–AgNP heterodimers combined through antigen–antibody reactions increased the sensitivity of the sensing platform by 50-fold. The proposed method gave a linear response for Cu2+ detection in the range of 0.5–1000 nM, with a detection limit of 0.18 nM, which is 5 orders of magnitude lower than the U.S. Environmental Protection Agency limit for Cu2+ in drinking water (20 μM). In addition, all analyses can be completed in less than 15 min. The high sensit...

We studied the material and photovoltaic properties of Sb

The defect properties of C H 3 N H 3 P b I 3 solar cells with efficiencies ranging from 7.70% to 12.51% were investigated using admittance spectroscopy measurements. Trap levels of the same kind with activation energies varied in the range of 0.16–0.23 eV above the valence band were found for different samples and identified as an interface-type defect. Moreover, the defect parameters, including the capture cross section of the holes, capture lifetime of the holes, and defect density, were extracted, and their relationships with the cell efficiencies were investigated. The results indicated that, compared with other parameters, defect density is a critical factor for C H 3 N H 3 P b I 3 solar cell performance.

The effect of the Cu/Ga ratio on properties of deep-level defects in CuGaSe

Properties of deep-level defects in CuGaSe

We use the multiple antibiotic resistance regulator (MarR), as a highly selective biorecognition elements in a multipath colourimetric sensing strategy for the fast detection of Cu2+ in water samples. The colourimetric assay is based on the aggregation of MarR-coated gold nanoparticles in the presence of Cu2+ ions, which induces a red-to-purple colour change of the solution. The colour variation in the gold nanoparticle aggregation process can be used for qualitative and quantitative detection of Cu2+ by the naked eye, and with UV–vis and smartphone-based approaches. The three analysis techniques used in the multipath colourimetric assay complement each other and provide greater flexibility for differing requirements and conditions, making the assay highly applicable for Cu2+ detection. Under optimal conditions, the Cu2+ concentration was quantified in less than 5 min with limits of detection for the naked eye, UV–vis and smartphone-based approaches of 1 μM, 405 nM and 61 nM, respectively. Moreover, the sensing system exhibited excellent selectivity and practical application for Cu2+ detection in real water samples. Thus, our strategy has great potential for application in on-site monitoring of Cu2+, and the unique response of MarR towards copper ions may provide a new approach to Cu2+ sensing.

A signal-amplified lateral flow test strip (SA-LFTS) for the detection of Cu2+ in aqueous solution was constructed based on Cu+-catalyzed click chemistry and hybridization of single-stranded DNA (ssDNA). Alkyne and azide modified ssDNA acted as specific elements for Cu2+ recognition, and a chemical ligation product formed through Cu+-catalyzed alkyne-azide cycloaddition. Hybridization of ssDNA-labeled gold nanoparticles resulted in high sensitivity, and the output signal could be observed directly by the naked eye. Using the developed SA-LFTS under optimal conditions, Cu2+ could be detected rapidly with limit of detections of 5 nM and 4.2 nM by visual observation and quantitative analysis, respectively. The sensitivity (i.e. the visual limit of detection) of the SA-LFTS was 80-times higher than that of traditional LFTS. The SA-LFTS was applied to the determination of Cu2+ in municipal water and river water samples with the results showing good recovery and accuracy. The developed test strip is promising for point-of-care applications and detection of Cu2+ in the field.

Spinel Mg(Al1−xGax)2O4 (x = 0–1) solid solutions were synthesized via solid-state method. Replacement of Al3+ by Ga3+ in MgAl2O4 gave rise to the expansion of the lattice, as well as blueshifts of FT-IR and Raman peaks. The homogeneous solid solutions, high relative densities, large grain sizes, and compact microstructures resulted in excellent microwave dielectric properties for spinel Mg(Al1−xGax)2O4 (x = 0.6) ceramics sintered at 1485°C: that is, er = 8.87, Q × f = 107 000 GHz (at 14.8 GHz), and τf = −16 ppm/°C. Spinel-structured Mg(Al1−xGax)2O4 (x = 0–1) solid solutions possessed low sintering temperatures, wide temperature regions (~100°C), and small negative τf values. These outstanding performance make Mg(Al, Ga)2O4 a promising candidate material for millimeter-wave devices.

Spinel MgGa2O4 ceramic materials were synthesized by solid-state method. MgGa2O4 powders were investigated with X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectrum, Raman spectrum, X-ray photoelectron spectrum (XPS), and high resolution transmission electron microscopy (HRTEM). The spinel-structured MgGa2O4 ceramics sintered at 1410 °C exhibited excellent microwave dielectric properties: a dielectric constant (ɛr) of 9.54, a quality factor (Q × f) of 117,000 GHz (at 14.7 GHz frequency) and a temperature coefficient of resonant frequency (τf) of −4.0 ppm/°C. MgGa2O4 ceramics have a wide sintering temperature region (∼150 °C) and nearly zero τf value. The large relative density, uniform microstructure and cation ordering resulted in high Q × f values. Crystal distortion from the oriented growth was advantageous to produce nearly zero τf value. MgGa2O4 ceramics are promising candidate materials for millimeter-wave devices.

Spinel ZnGa2O4 ceramics were synthesized by conventional solid-state method and their microwave dielectric properties were investigated. The phase evolution and microstructures of specimens were studied by XRD and SEM. The textured surface microstructures of ZnGa2O4 ceramics formed at high sintering temperatures. The spinel-structured ZnGa2O4 ceramics sintered at 1385°C exhibited excellent microwave dielectric properties: a dielectric constant (er) of 10.4, a quality factor (Q × f) of 94.600 GHz, and a temperature coefficient of resonant frequency (τf) of −27 ppm/°C. ZnGa2O4 ceramics have a low sintering temperature, a wide temperature region, and a small negative τf value. They are promising candidate materials for millimeter-wave devices.

Properties of deep-level defects in CuGaSe2 thin-film solar cells were investigated using photocapacitance methods. By measuring the transient photocapacitance spectra, a deep-level defect centered at around 0.8 eV above the valence band and a defect band located around 1.54 eV above the valence band were determined. A configuration coordinate model was used to explain the thermal quenching effect of the two defects. By measuring the steady-state photocapacitance, a fast increase, followed by a slow increase, was observed in the photocapacitance transient when the sample was illuminated by light with a photon energy of 0.8 eV at low temperature. Upon re-exposure by sub-bandgap light, an extra slow decrease in photocapacitance transient was observed. These observations were interpreted using a configuration coordinate model assuming two states for the 0.8 eV defect: a stable state D and a metastable state D* with a large lattice relaxation. The variation of the photocapacitance transients was attributed to the different optical transition processes of carriers between the two states of the 0.8 eV defect and the valence and conduction bands.

The properties of deep-level defects in Cu(In,Ga)Se2 thin films grown under different Se beam pressure were investigated by photocapacitance (PC) and time-resolved photoluminescence (TRPL) measurements. A generally known deep-level defect located at around 0.8 eV above the valence band was identified for all samples by transient photocapacitance measurement, the position of which was unvaried with the Se beam pressure. The defect concentration and the capture cross section of the minority carrier were obtained from the steady-state photocapacitance and TRPL measurements, which were evaluated to be on the order of 1013 cm−3 and 10−14 cm2, respectively, in the Se beam pressure range from 1.3×10−3 to 4.4×10−3 Pa. The relatively higher defect concentration and larger minority carrier capture cross section were considered as possible causes of the degradation of the conversion efficiency of CIGS solar cells grown under low Se beam pressure.