A Europium Metal-Organic Framework and Its Polymer Composite Membrane as Switch-Off Fluorescence Sensors for Antibiotic Detection in Lake Water.

The detection of antibiotic residues is of great significance in monitoring their overuse in healthcare, livestock and poultry farming, and agricultural production. Herein, EuCl3 and 4,4'-dicarboxyl-diphenoxyethene (H2DPOE) ionothermally reacted in 1-methyl-3-butylimidazolium chloride to give a europium metal-organic framework (Eu-DPOE). Eu-DPOE shows different fluorescence quenching rates for sensing eight antibiotics under different excitation wavelengths. Eu-DPOE displays a fast response, high selectivity, and sensitivity in antibiotic detection by fluorescence quenching. Eu-DPOE can sensitively detect TCs (tetracyclines), NOR (norfloxacin), NFT (furazolidone), ODZ (ornidazole), SDZ (sulfadiazine), and CHL (chloramphenicol) with limits of detection below 0.5 µmol/L. It provides a convenient and rapid tool for sensing antibiotics in aqueous solution. The detection mechanism is a competition absorption between DPOE2- and antibiotics with the supports from powder X-ray diffraction (PXRD), UV-vis spectra, and fluorescence lifetime. With a composite membrane of poly(vinylidene fluoride) (PVDF) matrix loading Eu-DPOE (Eu-DPOE@PVDF), Eu-DPOE@PVDF exhibits a visual fluorescence response to NOR under a 254 nm UV lamp and NFT and CTC under 365 nm. Eu-DPOE@PVDF is applied in the quantitative detection of CTC, NOR, and NFT in lake water with recovery rates ranging from 88.37 to 113.8%. Totally, fluorescence-quenched Eu-DPOE@PVDF exhibits a fast response, high selectivity, and sensitivity in sensing CTC, NOR, and NFT.

Zeolite-like Topology Oxonitridosilicate La3.6Ba1.7Si5N10O2.1 with Potential Applications in Nonlinear Optical Materials.

A novel zeolite-like topology oxonitridosilicate La3.6Ba1.7Si5N10O2.1 with the space group Amm2 (no. 38) and lattice parameters a = 9.5193 (3) Å, b = 16.7011 (5) Å, c = 26.0279 (8) Å, and Z = 12 has been synthesized by a high-temperature solid-state reaction. The crystal structure of La3.6Ba1.7Si5N10O2.1 has four different kinds of tiling, and the cages in the structure are filled with La, Ba, and O atoms. The presence of a noncentrosymmetric space group further suggests its potential for nonlinear optical (NLO) applications, and La3.6Ba1.7Si5N10O2.1 demonstrated a stronger second-harmonic generation (SHG) response than that of SiO2.

Fluorescent Eu3+/Tb3+ Metal-Organic Frameworks for Ratiometric Temperature Sensing Regulated by Ligand Energy.

This work presents three series of Eu/Tb metal-organic frameworks (MOFs) containing benzophenone-4,4'-dicarboxylic acid (H2BPNDC), 4,4'-dicarboxydiphenyl ether (H2OBA), and terephthalic acid (H2BDC) as the ligands. Eu/Tb MOFs have the same structural features in that their 3D frameworks are simplified as 2,3,10-connected {42.6}2{46.618.819.102}{4}2 topological networks. The solid-state fluorescence spectra of three Eu/Tb MOF series are attributed to the combined emissions of 5D0 → 7FJ (J = 1-4) transitions in Eu3+ and 5D4 → 7FJ (J = 6-5) transitions in Tb3+. The nEu:nTb of Eu/Tb MOFs is optimized as 1:69 based on the relationships between ITb(545)/IEu(614) and nEu:nTb; that is, Eu0.0143Tb0.9857-L (L = BPNDC2-, OBA2-, and BDC2-) were selected to carry out the following temperature (T)-sensing tests. The fluorescence mechanism of Eu0.0143Tb0.9857-L can be explained by a ligand-to-metal charge transfer combined with an intermetallic Tb3+ → Eu3+ energy transfer. The T-dependent fluorescence indicates linear relationships with sensitivities of 1.85% K-1 for Eu0.0143Tb0.9857-BPNDC, 6.49% K-1 for Eu0.0143Tb0.9857-OBA, and 0.28% K-1 for Eu0.0143Tb0.9857-BDC. The influence of T on the lowest excited triplet energy levels (T1 values) of the ligands reveals that the ligand energy regulation impacts their fluorescence properties, including the sensitivity, fluorescence quenching rate, quantum yield, and fluorescence lifetime. This shows that Eu0.0143Tb0.9857-BPNDC is sufficiently sensitive to T, making it applicable in noncontact T measurements.

[Research progress on pesticide residues of Panacis Quinquefolii Radix].

Panacis Quinquefolii Radix is the dry root of Panax quinquefolium, which is a perennial plant of Araliaceae. The plant has a long growth cycle and serious growth barrier problem, which leads to the use of pesticides. As a result, the pesticide residues in Panacis Quinquefolii Radix are arousing great concern. This paper reviews the research findings on the investigation, detection methods, content analysis and risk assessment of pesticide residues in Panacis Quinquefolii Radix since 1993, and compares the pesticide residue limit standards of different countries and regions. The pesticide residues in Panacis Quinquefolii Radix have been changing from organochlorines with high toxicity to triazines and triazoles with low toxicity. The pesticide residues are generally low, while the pollution of pentachloronitrobenzene and other pesticides still exist. The detection method has evolved from chromatography to chromatography-mass spectrometry. There are no reports of health risks caused by pesticide residues of Panacis Quinquefolii Radix. Pesticide residue is a major factor restricting the sound development of Panacis Quinquefolii Radix industry in China. Therefore, we suggest to improve the registration of pesticides applied to the plant, popularize mature ecological planting mode and supporting technology, and strengthen the research on the risk assessment and limit standard of pesticide residue in Panacis Quinquefolii Radix.

Structure and Luminescence Properties of Mn4+-Activated K3TaO2F4 Red Phosphor for White LEDs.

A novel red oxyfluoride phosphor K3TaO2F4:Mn4+ has been prepared by a simple two-step synthesis method. The structure, composition, and luminescence properties of K3TaO2F4:Mn4+ phosphors were investigated and discussed in detail. The real structure of K3TaO2F4 was carefully studied through X-ray powder diffraction data Rietveld refinement. K3TaO2F4 holds a D4 h group symmetry [TaO2F4]3- octahedron with the oxygen occupying the para-position. Under ultraviolet (UV) and blue light excitation, K3TaO2F4:Mn4+ phosphor emits a narrow band red emission peaking at 630 nm. High-performance warm white-light-emitting diodes (WLEDs) were fabricated using a blue LED chip, YAG:Ce3+ yellow phosphor, and K3TaO2F4:Mn4+ red phosphor. This device exhibits high color quality (CCT = 3488 K, Ra = 93.0, R9 = 90.0), which indicates that Mn4+-doped K3TaO2F4 would be a promising red phosphor for WLED applications.

ECG conduction disturbances and ryanodine receptor expression levels in occupational lead exposure workers.

OBJECTIVES: A significant number of researches have evidenced that occupational lead (Pb) exposure increased risks of cardiovascular disease. However, evidences about the potential effects of Pb on the cardiac conduction system are sparse and inconclusive. Besides, ryanodine receptors (RyRs) induced dysfunction of cardiac excitation contraction coupling which is considered to be one of the mechanisms in cardiovascular diseases. Therefore, we examined the association between occupational Pb exposure and ECG conduction abnormalities, as well as RyRs in Pb-induced ECG abnormalities. METHODS: We investigated 529 Pb smelter workers, and measured blood lead (BPb), zinc protoporphyrin (ZPP), ECG outcomes and RyR expression levels. Based on BPb levels, the workers were divided into three groups: the BPb not elevated group, the BPb elevated group and the Pb poisoning group. Descriptive and multivariable analyses were performed. RESULTS: Compared with the BPb not elevated group, the Pb poisoning group had a higher incidence of high QRS voltage, and a lower level of RyR1 gene expression (p<0.05). Further unconditional multivariable logistic regression analyses showed that high QRS voltage was positively related to BPb (OR=1.045, 95% CI 1.014 to 1.078) and inversely associated with RyR1 expression (OR=0.042, 95% CI 0.002 to 0.980) after adjusting for potential confounders. In addition, multiple linear regression analyses showed that the QTc interval was positively associated with ZPP (ß=0.299, 95% CI 0.130 to 0.468) after adjusting for potential confounders. CONCLUSIONS: Our study provided evidences that occupational exposure to Pb may be associated with worse ECG outcomes (high QRS voltage), which might be related to decreased levels of RyR1.

Investigating the Luminescence Behaviors and Temperature Sensing Properties of Rare-Earth-Doped Ba2In2O5 Phosphors.

We present a strategy for selecting an optimal material in a particular temperature range by investigating the relationship between the absolute sensitivity ( Sa) and energy gap (Δ E), as well as the relationship between Sa and temperature on the basis of Yb3+/Ln3+ (Ln = Er3+, Ho3+)-codoped Ba2In2O5 phosphors. Through an investigation of optical performance, the phosphors exhibit near-infrared (NIR) downshifting and visible upconversion (UC) emissions under 980 nm excitation. The NIR spectral range from 700 to 1800 nm is referred to as the "biological window". The NIR emission peaks of Er3+ and Ho3+ are located at 1550 nm of the third biological window and 1192 nm of the second biological window, respectively. The temperature sensing behaviors based on the UC luminescence in Yb3+/Ln3+-codoped Ba2In2O5 phosphors are recorded by the fluorescence intensity ratio (FIR) technique in the temperature range from 303 to 573 K. The Ba2In2O5:Er3+/Yb3+ sample is usable at temperatures above 350 K, and the Ho3+/Yb3+-codoped Ba2In2O5 phosphor is suitable at temperatures below 350 K in our experimental region. The above results show that the Ba2In2O5:Ln3+/Yb3+ phosphors could be promising candidates for optical temperature sensors and applications in the biological imaging field.

Novel switchable sensor for phosphate based on the distance-dependant fluorescence coupling of cysteine-capped cadmium sulfide quantum dots and silver nanoparticles.

A novel switchable sensor was developed for the determination of phosphate based on Ce(3+) induced aggregation and phosphate triggered disaggregation of cysteine (Cys)-capped CdS quantum dots (QDs) and silver nanoparticles (AgNPs). The rare earth metal Ce(3+) could aggregate a mixture of QDs and AgNPs, which induced electron or energy transfer between CdS QDs and AgNPs and serious fluorescence quenching. However, phosphate dissociated the formed aggregation of CdS QDs and AgNPs, restoring the enhanced fluorescence of Cys-capped CdS triggered by AgNPs. Although, CdS QDs alone could also be used to detect phosphate through the aggregation-disaggregation mechanism adjusted by Ce(3+) and phosphate. It was found that the distance-dependent interaction between AgNPs and CdS QDs driven by Ce(3+) and phosphate could lead to enhanced quenching or enhancement of the fluorescence of Cys-capped CdS to form a more sensitive detection system for phosphate. The developed method was applied in the detection of phosphate in real water samples with acceptable and satisfactory results.

[Effect of lead exposure on brain iron in aged rats based on the MRI].

OBJECTIVE: To explore the effect of long-term lead exposure on brain iron in aged rats. METHODS: SPF female and male Sprague-Dawley rats were respectively randomly divided into three groups: control, low lead-exposed, high lead-exposed. Lead-exposed female rats drank 0.8g/L or 1.5g/L lead acetate solutions through pregnancy until weaning and then the pups received 0.3g/L or 0.9g/L lead acetate solution depending on their group. Control group rats drank deionized water throughout the experiment. At the postnatal 18 months, one pup for per group was given an ultra structural detection of hippocampus, and the other male pups were measured the lead and iron concentration of blood and brain by GE MR 3.0T MR scanner and ICP-AES. RESULTS: In comparing with control group, the lead concentrations of blood and brain in lead-exposed groups were significantly higher, and the iron contents of brain and cortex, hippocampus, thalamus were significantly higher in 0.9g/L lead-exposed group. Also, it was highly positively correlated between blood lead and iron of blood, cortex, hippocampus, thalamus, respectively. With the dose of lead-exposed increased, cytoplasm, nucleus, mitochondrial structure and synaptic structure had suffered vary degrees of damage from ultra structural detection of hippocampus, it could be observed early neuronal apoptosis. CONCLUSION: Lead induced neurodegenerative diseases might be related to iron overload which caused by lead exposure.

Lignin-Based Materials for Additive Manufacturing: Chemistry, Processing, Structures, Properties, and Applications.

The utilization of lignin, the most abundant aromatic biomass component, is at the forefront of sustainable engineering, energy, and environment research, where its abundance and low-cost features enable widespread application. Constructing lignin into material parts with controlled and desired macro- and microstructures and properties via additive manufacturing has been recognized as a promising technology and paves the way to the practical application of lignin. Considering the rapid development and significant progress recently achieved in this field, a comprehensive and critical review and outlook on three-dimensional (3D) printing of lignin is highly desirable. This article fulfils this demand with an overview on the structure of lignin and presents the state-of-the-art of 3D printing of pristine lignin and lignin-based composites, and highlights the key challenges. It is attempted to deliver better fundamental understanding of the impacts of morphology, microstructure, physical, chemical, and biological modifications, and composition/hybrids on the rheological behavior of lignin/polymer blends, as well as, on the mechanical, physical, and chemical performance of the 3D printed lignin-based materials. The main points toward future developments involve hybrid manufacturing, in situ polymerization, and surface tension or energy driven molecular segregation are also elaborated and discussed to promote the high-value utilization of lignin.

CrP Nanocatalyst within Porous MOF Architecture to Accelerate Polysulfide Conversion in Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries demonstrate great potential for next-generation electrochemical energy storage systems because of their high specific energy and low-cost materials. However, the shuttling behavior and slow kinetics of intermediate polysulfide (PS) conversion pose a major obstacle to the practical application of Li-S batteries. Herein, CrP within a porous nanopolyhedron architecture derived from a metal-organic framework (CrP@MOF) is developed as a highly efficient nanocatalyst and S host to address these issues. Theoretical and experimental analyses demonstrate that CrP@MOF has a remarkable binding strength to trap soluble PS species. In addition, CrP@MOF shows abundant active sites to catalyze the PS conversion, accelerate Li-ion diffusion, and induce the precipitation/decomposition of Li2S. As a result, the CrP@MOF-containing Li-S batteries demonstrate over 67% capacity retention over 1000 cycles at 1 C, ∼100% Coulombic efficiency, and high rate capability (674.6 mAh g-1 at 4 C). In brief, CrP nanocatalysts accelerate the PS conversion and improve the overall performance of Li-S batteries.

BaLa5V2O3N7: a novel anti-perovskite oxynitride for electrode applications.

The exploration of transition metal oxynitrides has garnered significant interest due to their intriguing property diversity. Herein, we present a promising new transition metal oxynitride BaLa5V2O3N7, which features an anti-perovskite structure type. This unique structural configuration endows the material with remarkable conductivity, particularly at low temperatures, paving the way for the material to be used in a wide range of technological applications.

Preparation and electrical properties of inorganic electride [Y2Ti2O6]2+(2e-).

Oxygen-depleted samples [Y2Ti2O7-x ]2x+(2xe-) (0 ≤ x ≤ 1.0) were prepared by reducing Y2TiO7 powders at 500 °C to 650 °C using CaH2 as a reductive agent, where x represents the content of , which was determined by thermogravimetric analysis. Powder X-ray diffraction patterns illustrate that the pure pyrochlore phase is kept for the samples with x ≤ 1.0, whereas the apparent x values surpass 1.0, and the impurity phase Y2O3 appears. The electride [Y2Ti2O7-x ]2x+(2xe-) (x ≈ 1.0) can be obtained under a reductive condition, in which the concentration of VO is 7.75 × 1021 cm-3. The electron paramagnetic resonance measurements gave the concentration of unpaired electrons in the electride as 1.30 × 1021 cm-3, indicating that the degree of the ionization of is less than 10%. Conductivity measurements for a sintered pellet sample (relative density ∼ 70%) indicate that the electride has quite high conductivity (∼1.09 S cm-1 at 300 K). The conduction was interpreted by using the variable range hopping mechanisms.

Synthesis and luminescence properties of new nitridolithosilicate phosphor La4Ba3Li3Si9N19:Pr3+ grown in Li flux.

Flux synthesis is an effective method to discover large crystals of new compounds. In this paper, a solid-state reaction in Li flux produced a new nitridolithosilicate La4Ba3Li3Si9N19 in the orthorhombic space group Cmcm (No. 63) with lattice parameters of a = 9.7263(1), b = 18.2746(2), c = 11.2929(1) Å, and Z = 4. The La4Ba3Li3Si9N19 exhibits a 3-D framework based on triangular clusters (3-rings) formed by vertex-sharing SiN4 tetrahedra. The rare earth Pr3+-doped La4Ba3Li3Si9N19 emits a narrow-band red emission peaking at approximately 640 nm with a full width at half-maximum of 50 nm when excited under ultraviolet light.

Tuning multicolour emission of Zn2GeO4:Mn phosphors by Li+ doping for information encryption and anti-counterfeiting applications.

Traditional fluorescent materials used in the anti-counterfeiting field usually exhibit monochromatic luminescence at a single-wavelength excitation, which is easily forged by sophisticated counterfeiters. In this work, Zn2GeO4:Mn,x%Li (x = 0 and 20), Zn2GeO4-NaLiGe4O9:Mn,x%Li (x = 50 and 70) and NaLiGe4O9:Mn micro-phosphors with multi-chromatic and multi-mode luminescence have been successfully synthesized via a hydrothermal approach followed by an annealing treatment. As expected these Li+ doped Zn2GeO4:Mn and Zn2GeO4-NaLiGe4O9:Mn phosphors exhibit a double peak emission including a long green afterglow (∼540 nm) and red photoluminescence (∼668 nm). By tuning Li+ doping concentrations, a gradual colour output and a tuneable afterglow duration are achieved. In particular, the Zn2GeO4:Mn,Li and NaLiGe4O9:Mn phosphors exhibit excellent performance as security inks for printing luminescent numbers and anti-counterfeiting patterns, which show an afterglow time-dependent or excitation wavelength-dependent luminescence colour evolution. This work proves the feasibility of the Li+ doping strategy in emission tuning, which can stimulate further studies on multi-mode luminescent materials for anti-counterfeiting applications.

Ultrasensitive and selective colorimetric detection of thiourea using silver nanoprobes.

A novel colorimetric thiourea (TU) sensor was developed utilizing citrate modified silver nanoparticles (AgNPs). The introduction of TU reduced the overall surface charges of the AgNPs, resulting in aggregation of AgNPs and a colorimetric response correlating with the concentration of TU. The detection of TU could be realized within 2 min, with an ultralow detection limit of 0.8 nM by the absorption method. In addition, the AgNPs sensor also showed good selectivity in the presence of potential interfering compounds. Since common steps such as modification and separation could be successfully avoided, the sensor developed here could provide a simple, cost-effective yet rapid and sensitive measurement tool for TU detection, and may provide new opportunities in the development of sensors for food safety and environmental monitoring in the future.

Fabrication of SiO2@ZrO2@Y2O3:Eu3+ core-multi-shell structured phosphor.

ZrO2 interface was designed to block the reaction between SiO2 and Y2O3 in SiO2@Y2O3:Eu coreshell structure phosphor. SiO2@ZrO2@Y2O3:Eu core-multi-shell phosphors were successfully synthesized by combing an LBL method with a Sol-gel process. Based on electron microscopy, X-ray diffraction, and spectroscopy experiments, compelling evidence for the formation of the Y2O3:Eu outer shell on ZrO2 were presented. The presence of ZrO2 layer on SiO2 core can block the reaction of SiO2 core and Y2O3 shell effectively. By this kind of structure, the reaction temperature of the SiO2 core and Y2O3 shell in the SiO2@Y2O3:Eu core-shell structure phosphor can be increased about 200-300 degrees C and the luminescent intensity of this structure phosphor can be improved obviously. Under the excitation of ultraviolet (254 nm), the Eu3+ ion mainly shows its characteristic red (611 nm, 5D0-7F2) emissions in the core-multi-shell particles from Y2O3:Eu3+ shells. The emission intensity of Eu3+ ions can be tuned by the annealing temperatures, the number of coating times, and the thickness of ZrO2 interface, respectively.

A hetero-MOF-based bifunctional ratiometric fluorescent sensor for pH and water detection.

The detection of pH and water is of significance in natural and production processes. The ionothermal reactions of 4,4'-oxybisbenzoic acid (H2OBA) with Eu3+ and Tb3+ produced [M(OBA)(H2O)Cl] (M = Eu3+ (1) and Tb3+ (2)) and heteronuclear [Eu0.05Tb0.95(OBA)(H2O)Cl] (3). 3 emits the combined characteristic transitions of Eu3+ and Tb3+. Its energy transition processes can be disturbed by pH and water. The emission colors of 3 follow pH changes. It emits blue light when pH = 1-2, in which OBA2- turns into H2OBA based on the acid-base equilibrium. When pH = 3-11, the emission colors change from green to orange and ITb/IEu exhibits a linearity of ITb/IEu = 6.7482-0.5971·pH; the emissions are quenched at pH = 12-13, due to OH- destroying the delocalized conjugated system of 3. 3 shows a fluorescence response to water with a linearity of ITb/IEu = 0.30353 + 0.15042·VH2O% within 0-0.8% VH2O%. The green (G) and red (R) color intensities of the paper-based MOF sensor of 3 reveal a trinomial fitting equation of G/R = 4.16334 - 1.23014·pH + 0.14036·pH2- 0.00551·pH3 when pH = 3-11. 3 can be used as a ratiometric fluorescent sensor to detect pH and water and the paper-based MOF sensor can also be used in on-site pH detection.

Narrow-band red emitting oxonitridosilicate phosphor La4-xSr2+xSi5N12-xOx:Pr3+ (x≈ 1.69).

The new oxonitridosilicates Ln4-xSr2+xSi5N12-xOx (Ln = La, Ce) were synthesized by high temperature solid-state reactions. The crystal structures were solved and refined from both single-crystal and powder X-ray diffraction data. These oxonitridosilicate compounds crystallize in the monoclinic space group P21/n (no. 14) and exhibit a double-layer structure made up of corner-sharing Si(O/N)4 tetrahedra. When excited with near-UV and blue light, the Pr3+ doped La2.31Sr3.69Si5N10.31O1.69 phosphor shows a narrow-band red emission peaking at 625 nm with a full width at half-maximum of 40 nm.

Acute Effects of Sleeve Gastrectomy on Glucose Variability, Glucose Metabolism, and Ghrelin Response.

PURPOSE: This study aims to examine the changes of glucose metabolism, glucose variability (GV), and ghrelin secretion within 1 week following SG in Chinese patients with obesity. MATERIALS AND METHODS: Forty-nine patients with obesity (15 with type 2 diabetes) were enrolled to undergo SG. Within 1 week before and after surgery, liquid meal tests were performed in all subjects, and continuous glucose monitoring (CGM) was performed in diabetic patients. Blood samples were collected at 0, 15, 30, 45, 60, 120, and 180 min for glucose, C-peptide, insulin, and ghrelin analysis in liquid meal test. Mean amplitude of glucose excursions (MAGE), standard deviations (SD), and percent time-in-range (%TIR) determined by CGM were analyzed. RESULTS: Both in diabetic and non-diabetic groups, significant decrease was observed in glucose, insulin, C-peptide, and ghrelin. Homeostasis model assessment-insulin resistance and liver fat content was decreased. In diabetic group, MAGE and SD were decreased significantly, and the percent time-in-range was higher. The decrease in blood glucose was positively correlated with the decrease in ghrelin concentration in non-diabetic group. CONCLUSION: Within 1 week after SG, both glucose metabolism and glucose variability were improved significantly. Suppression of ghrelin secretion postoperatively might be a driver of this early improved glycemia homeostasis.