Effect of Miscellaneous Meals Replacing Soybean Meal in Feed on Growth Performance, Serum Biochemical Parameters, and Microbiota Composition of 25-50 kg Growing Pigs.

The present study aims to determine the effect of miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower meal) replacing soybean meal in feed on growth performance, apparent digestibility of nutrients, serum biochemical parameters, serum free amino acid content, microbiota composition and SCFAs content in growing pigs (25-50 kg). A total of 72 (Duroc × Landrace × Yorkshire) growing pigs with initial weights of 25.79 ± 0.23 kg were randomly divided into three treatments. The pigs were fed corn-soybean meal (CON), corn-soybean-miscellaneous meals (CSM), and corn-miscellaneous meals (CMM). Each treatment included six replicates with four pigs per pen (n = 24, 12 barrows and 12 gilts). Soybean meal accounted for 22.10% of the basal diet in the CON group. In the CSM group, miscellaneous meals partially replaced soybean meal with a mixture of 4.50% rapeseed meal, 3.98% cottonseed meal, and 4.50% sunflower meal. In the CMM group, miscellaneous meals entirely replaced soybean meal with a mixture of 8.50% rapeseed meal, 8.62% cottonseed meal, and 8.5% sunflower. The results showed that compared with the CON, the CSM and CMM groups significantly improved the average daily gain (ADG) of growing pigs during the 25-50 kg stage (p < 0.05) but had no effects on average daily feed intake (ADFI) and average daily feed intake/average daily gain (F/G) (p > 0.05). Moreover, the CMM group significantly reduced nutrient apparent digestibility of gross energy compared with the CON group. The serum biochemical parameters results showed that the CSM group significantly improved the contents of total protein (TP) compared with the CON group (p < 0.05). The CMM group significantly improved the contents of total protein (TP), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) compared with the CON group in serum (p < 0.05). In comparison with the CON group, the CMM group also significantly improved lysine (Lys), threonine (Thr), valine (Val), isoleucine (Ile), leucine (Leu), phenylalanine (Phe), arginine (Arg), and citrulline (Cit) levels in serum (p < 0.05). However, the CMM group significantly decreased non-essential amino acid content glycine (Gly) in serum compared with CON (p < 0.05), while compared with the CON group, the CSM and CMM groups had no significant effects on the relative abundance, the alpha-diversity, or the beta-diversity of fecal microbiota. Moreover, compared with the CON group, the CSM group significantly increased butyric acid and valeric acid contents of short-chain fatty acids (SCFAs) in feces (p < 0.05). In contrast to the CON group, the CMM group significantly reduced the contents of SCFAs in feces, including acetic acid, propionic acid, and isobutyric acid (p < 0.05). Collectively, the results of the present study indicate that miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower meal) can partially replace the soybean meal and significantly improve the growth performance of growing pigs during the 25-50 kg stage. Thus, miscellaneous meals are a suitable protein source as basal diets to replace soybean meals for 25-50 kg growing pigs. These results can be helpful to further develop miscellaneous meals as a functional alternative feed ingredient to soybean meal.

Effect of mixed meal replacement of soybean meal on growth performance, nutrient apparent digestibility, and gut microbiota of finishing pigs.

Introduction: This study was carried out to investigate the effects of mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacement soybean meal on growth performance, nutrient apparent digestibility, serum inflammatory factors and immunoglobulins, serum biochemical parameters, intestinal permeability, short-chain fatty acid content, and gut microbiota of finishing pigs. Methods: A total of 54 pigs with an average initial weight of 97.60 ± 0.30 kg were selected and randomly divided into 3 groups according to their initial weight, with 6 replicates in each group and 3 pigs in each replicate. The trial period was 26 days. The groups were as follows: control group (CON), fed corn-soybean meal type basal diet; Corn-soybean-mixed meal group (CSM), fed corn-soybean meal-mixed meal diet with a ratio of rapeseed meal, cotton meal, and sunflower meal of 1:1:1 to replace 9.06% soybean meal in the basal diet; Corn-mixed meal group (CMM), fed a corn-mixed meal diet with a ratio of Rapeseed meal, Cotton meal and Sunflower meal of 1:1:1 to replace soybean meal in the basal diet completely. The crude protein level of the three diets was maintained at 12.5%. Results: Our findings revealed no significant impact of replacing soybean meal with the mixed meal (rapeseed meal, cotton meal, and sunflower meal) on the ADG (Average daily gain), ADFI (Average daily feed intake), and F/G (Feed gain ratio) (P > 0.05), or crude protein, crude fat, and gross energy (P > 0.05) in the diet of finishing pigs. Compared with the CON group, the serum interleukin 6 (IL-6) and interleukin 10 (IL-10) concentrations were significantly decreased in the CMM group (P < 0.05). However, there is no significant effect of the mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacing soybean meal in the diet on the serum interleukin 1ß (IL-1ß), interleukin 8 (IL-8), tumor necrosis factor-alpha (TNF-α), immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations (P > 0.05). Concordantly, there is no significant effect of mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacing soybean meal in the diet on the serum antioxidant capacity, such as total antioxidant capacity (T-AOC), catalase (CAT), and malondialdehyde (MDA) levels of finishing pigs. Moreover, compared with the CON group, serum low-density lipoprotein (LDL-C) levels were significantly lower in the CSM group (P < 0.05) and their total bilirubin (TBIL) levels were significantly lower in the CMM group (P < 0.05). There is not a significant effect on serum D-lactate and diamine oxidase (DAO) concentrations (P > 0.05). The next section of the survey showed that the replacement of soybean meal with a mixed meal (rapeseed meal, cotton meal, and sunflower meal) in the diet did not significantly influence the acetic acid, propionic acid, butyric acid, valeric acid, isobutyric acid, and isovaleric acid in the colon contents (P > 0.05). Furthermore, compared with the CON group, the CMM group diet significantly increased the abundance of Actinobacteria at the phylum level (P < 0.05), U_Actinobacteria at the class level (P < 0.05), and U_Bacteria at the class level (P < 0.05). The result also showed that the CMM group significantly reduced the abundance of Oscillospirales at the order level (P < 0.05) and Streptococcaceae at the family level (P < 0.05) compared with the CON group. The Spearman correlation analysis depicted a statistically significant positive correlation identified at the class level between the relative abundance of U_Bacteria and the serum T. BILI concentrations (P < 0.05). Moreover, a significant negative correlation was detected at the order level between the relative abundance of Oscillospirales and the levels of acetic and propionic acids in the colonic contents (P < 0.05). Additionally, there was a significant positive correlation between the serum concentrations of IL-6 and IL-10 and the relative abundance of the family Streptococcaceae (P < 0.05). Discussion: This study demonstrated that the mixed meal (rapeseed meal, cotton meal, and sunflower meal) as a substitute for soybean meal in the diet had no significant negative effects on the growth performance, nutrient apparent digestibility, serum immunoglobulins, serum antioxidant capacity, intestinal permeability, short-chain fatty acid content, and diversity of gut microbiota of finishing pigs. These results can help develop further mixed meals (rapeseed meal, cotton meal, and sunflower meal) as a functional alternative feed ingredient for soybean meals in pig diets.

Directional and Eye-Tracking Light Field Display with Efficient Rendering and Illumination.

Current efforts with light field displays are mainly concentrated on the widest possible viewing angle, while a single viewer only needs to view the display in a specific viewing direction. To make the light field display a practical practice, a super multi-view light field display is proposed to compress the information in the viewing zone of a single user by reducing the redundant viewpoints. A quasi-directional backlight is proposed, and a lenticular lens array is applied to achieve the restricted viewing zone. The eye-tracking technique is applied to extend the viewing area. Experimental results show that the proposed scheme can present a vivid 3D scene with smooth motion parallax. Only 16.7% conventional light field display data are required to achieve 3D display. Furthermore, an illumination power of 3.5 watt is sufficient to lighten a 31.5-inch light field display, which takes up 1.5% of the illumination power required for planar display of similar configuration.

Rapid, accurate, multifunctional and self-assisted vision assessment and screening with interactive desktop autostereoscopy.

BACKGROUND: This study aimed to develop an interactive vision screening tool based on desktop autostereoscopy and evaluate its feasibility for testing visual acuity, colour vision, stereo vision and binocular balance clinically. METHODS: An interactive desktop autostereoscopy vision test was developed making it remarkably convenient for individuals to undergo multiple visual function assessments in a single test. With this rapid screening process, an individual's visual acuity, colour vision, stereo vision and binocular balance can be assessed within several minutes. A total of 155 healthy subjects were enrolled to compare the clinical repeatability, accuracy, inter-visit variability, likeability and efficiency between the autostereoscopy and traditional method. RESULTS: In the repeatability test, the visual acuity measured with autostereoscopy was 0.045±0.018 and 0.035±0.018 (P=0.702) for the first and second tests, respectively. The mean logarithm of the Minimum Angle of Resolution (logMAR) visual acuities measured with the Early Treatment Diabetic Retinopathy Study (EDTRS) chart and autostereoscopy test were 0.04±0.02 and 0.05±0.02, respectively, which were not significantly different (P=0.849). The correlation between these two kinds of tests was statistically significant (Spearman correlation coefficient =0.829, P<0.001). The results for colour vision, stereo vision, and binocular vision are presented, and the effectiveness of the autostereoscopic method is supported with qualitative data comparing its results with those of the traditional methods. In the likeability test, the EDTRS chart and autostereoscopy test had scores of 2.21±0.53 and 3.04±0.07, while the traditional and autostereoscopy tests for colour vision, stereo vision, and binocular vision had scores of 2.02±0.59 and 3.36±0.93, respectively (P<0.001). Regarding visual fatigue, the mean scores were 0.69±0.04 and 0.42±0.04 (P<0.001) with the EDTRS chart and autostereoscopy test, respectively. Regarding work efficiency, the average testing times per person was 59.65±0.66 and 48.92±0.86 s (P<0.001) with the EDTRS chart and autostereoscopy test, respectively. CONCLUSIONS: The autostereoscopy test was conclusively shown to be valid, efficient and repeatable for the measurement of visual acuity, colour vision, stereo vision, and binocular vision, and the process was subjectively well-liked and comfortable.

Novel Strategy for Engineering the Metal-Oxide@MOF Core@Shell Architecture and Its Applications in Cataluminescence Sensing.

Cataluminescence is an attractive oxydic luminescence on the gas-solid interface, and metal-oxide@MOF core@shell architectures show great potential for cataluminescence sensing due to their integrated synergistic effect from core and shell components. However, restricting the direct nucleation and growth of metal-organic frameworks (MOFs) on the topologically distinct surface of metal oxides is a great challenge, owing to the high interface energy from the topology mismatch. Herein, for the first time, a novel liquid-phase concentration-controlled nucleation strategy is exploited to induce the direct assembly of a ZIF-8 layer on the surface of CeO2 nanospheres without any sacrificial templates or further surface modifications. The results show that the construction of the CeO2@ZIF-8 core@shell architecture can be accomplished within 1 min under the mediation of boosted nucleation kinetics. Furthermore, the universality of this developed strategy is demonstrated by the encapsulation of other metal-oxide cores such as magnetic Fe3O4 and ZnCo2O4 core particles with a ZIF-8 shell. Notably, compared to the pure CeO2 and ZIF-8, the obtained CeO2@ZIF-8 nanocomposite exhibits enhanced analytical performance for the cataluminescence sensing of propanal, in which the shell acts as the major catalytic reaction center, while the core contributes to further improving the catalytic efficiency. The proposed facile synthesis strategy with excellent simplicity, rapidity, and universality brings new insights into the engineering of core@shell advanced functional materials with mismatched topologies for catering to the diverse application demands.

Engineering Ratiometric Persistent Luminous Sensor Arrays for Biothiols Identification.

Thiols play vital roles in mediating physiological processes. However, it is difficult to discriminate one thiol from another because of the similarities among structures and reactivities of thiols. In light of the ultralow background and impressive discrimination power, a persistent luminescence-based sensing array has attracted increasing attention but still remains a huge challenge. Herein, we have thoroughly studied the chemistry involving dual-emission persistent luminescence nanoparticles (D-PLNPs) with metal ions (MIs) and for the first time proposed an MIs-triggered ratiometric persistent luminescence (R-PersL) sensor array for the discrimination of six thiols. To extract data-rich outputs from a single sensor element, three representative D-PLNPs with a core-shell structure and subsequent carboxyl functionalizations (CSD-PLNPs) were rationally fabricated. Interestingly, MIs revealed the different regulating efficiencies for the two main emission bands of CSD-PLNPs, resulting from MI-triggered R-PersL signal transductions. Inspired by the crucial roles of thiols in vivo, a proof-of-concept sensor array through the ensemble of CSD-PLNPs-COOH and certain MIs was developed and demonstrated aR-PersL "fingerprint" pattern identification for six thiols. Remarkably, because of the autofluorescence-free background and high-throughput signal output, this sensing array system enabled a highly sensitive and differentiable detection of thiols at various concentrations in human blood serums, paving a new way to develop multiparameters sensing for complex analytes.

Mass Spectrometric Assay of Alpha-Fetoprotein Isoforms for Accurate Serological Evaluation.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death, which is demanding powerful diagnosis tools. Although the traditionally used serological biomarker alpha-fetoprotein (AFP) cannot meet the  requirement of accurate diagnosis, its isoform alpha-fetoprotein L3 (AFP-L3) ratio in total AFP is emerging as a highly specific alternative. The routine electrophoretic blotting methods for analyzing AFP-L3 isoform ratio are reliable but often lack speediness, sensitivity, or accuracy. Herein, an elemental mass spectrometric strategy was established to simultaneously detect total AFP and AFP-L3 for the accurate HCC diagnosis. The metal isotopes inside colloidal gold nanoparticle (AuNP) and colloidal silver nanoparticle (AgNP) reporters were used to sensitively detect total AFP and AFP-L3, respectively. AFP-L3 and total AFP were accurately and simultaneously detected with the limits of detection (LODs) of 0.1 ng mL-1 and 0.2 ng mL-1, respectively. The proposed method was successfully validated in a series of human serum samples. The assay procedure was greatly simplified and less time-consuming for the AFP-L3 isoform ratio evaluation, when compared to clinical routine chromatographic/electrophoretic methods. Thanks to the highly multiplex ability of mass spectrometry, the proposed method provides great potential for the analysis of multiple isoforms of various disease biomarkers.

Engineering the energy gap of black phosphorene quantum dots by surface modification for efficient chemiluminescence.

In this work, NH2-functionalized BPQDs (N-BPQDs) were purposely synthesized by using an ultrasound exfoliation technique combined with solvothermal treatment. The surface modification of BPQDs allowed engineering the energy gap and accelerating the electron transfer between the electron/hole donors and N-BPQDs, which played an important role in producing efficient chemiluminescence (CL) with the assistance of persulfate (K2S2O8). This work sheds new light on revealing the relationship between the BPQD structures and their optical properties.

Cataluminescence Coupled with Photoassisted Technology: A Highly Efficient Metal-Free Gas Sensor for Carbon Monoxide.

With the development of green chemistry, metal-free nanocatalysts have gradually substituted metal-based materials, causing widespread concern among researchers in many fields, especially in cataluminescence sensing, because of their long-term stability and environmental friendliness as well as low costs. Besides the catalysts, innovations of assistant technologies for cataluminescence are needed to enhance the oxidation reactivity of the gas molecules or catalytic efficiency of sensing materials. Although, there are some groups enhancing the cataluminescence reaction via various assistant technologies, the development of assistant technologies in cataluminescence sensors is still in its infancy; the design, effect mechanism, and application are still stimulating challenges. Herein, with photodynamic assistant, fluorinated nanoscale hexagonal boron nitride is first employed as a metal-free catalyst to establish a novel cataluminescence method for detecting CO gases, and the cataluminescence reaction mechanism of CO is also investigated in detail. Under the best conditions, the detection limit (3σ) of the CO concentration is 0.005 µg mL-1, which has been largely improved in cataluminescence methods. The realization of detection of CO from theory to practice through the method of cataluminescence is beneficial for the practical application of metal-free catalysts to detect CO rather than staying at the possibility to detect CO by means of theoretical calculation only.

Chemiluminescence of Oleic Acid Capped Black Phosphorus Quantum Dots for Highly Selective Detection of Sulfite in PM2.5.

Quantum dots (QDs), especially metal-free QDs with their unique optoelectronic properties, environmental friendliness, and excellent biocompatibility, have opened a new avenue to explore novel chemiluminescence (CL) systems for analytical applications. However, the unknown CL properties, relatively weak emission, and instability of some of them in water (e.g., black phosphorus QDs) often seriously hinder their further practical applications. Chemical modification trends have offered new properties for materials and have been proved to be desirable ways to establish sensing platforms with improved sensitivity and stability. Herein, oleic acid capped black phosphorus QDs (OA-BP QDs) with improved stability and optical properties were successfully synthesized. More importantly, an extraordinary CL emission when OA-BP QDs reacted with SO32- was first observed. In the CL process, OA-BP QDs acted as the catalyst to trigger singlet oxygen (1O2) generation in NaHSO3, and then a chemiluminescence resonance energy transfer (CRET) between (1O2)2* (1O2 dimeric aggregate) and OA-BP QDs was produced. On this basis, a new CL system for directly monitoring SO32- in airborne fine particulate matter (PM2.5) was fabricated. The study opens attractive perspectives of modified metal-free QDs for the practice of CL in monitoring the chemical species in PM2.5.

Fluorescence nano metal organic frameworks modulated by encapsulation for construction of versatile biosensor.

The versatile fluorescence biosensors were implemented based on multipurpose nano metal organic frameworks (nMOFs) nanocomposites, which were obtained as fluorescence signal probes through encapsulation nMOFs. In this modulation process, the encapsulant bind with nMOFs through electrostatic attraction and hydrogen bond. Meanwhile, fluorescence enhancement of nMOFs were observed, accompanied by an increased in water solubility. The specific combination of target analyte triggers the release of the encapsulant and allows the target analyte to bind encapsulant to form a stable analyte-encapsulant complex. The complex binds tightly and promotes the photoinduced electron transfer from MOFs nanocomposites to the complex, thus resulting in reduce the fluorescence intensity of the MOFs nanocomposites. The results indicated that this novel system enables the specific and versatile detection of target biomolecules such as hemin and folic acid with high sensitivity and selectivity based on the choices of different encapsulant. Under optimized conditions, these biosensors show high sensitivity with a linear range from 0.16 to 12.5 µg/mL for hemin and 0.15-17.5 µmol/L for folic acid and detection limit of 47 ng/mL for hemin and 45 nmol/L folic acid. Moreover, it exhibits good performance of excellent selectivity, high stability, and acceptable fabrication reproducibility. This new multipurpose MOFs nanocomposites open avenues for combining together their properties and functionalities, and displaying novel important applications in fluorescence biosensors.

UV-Assisted Cataluminescent Sensor for Carbon Monoxide Based on Oxygen-Functionalized g-C3N4 Nanomaterials.

Cataluminescence (CTL) is one of the most important sensing-transduction principles for the real-time monitoring of atmospheric pollutants. Highly sensitive CTL-based CO detection still remains a challenge because of the relatively poor reactivity of CO and the low catalytic efficiency of the catalysts. Herein, combining ultraviolet (UV)-light activation and chemical modification of the sensing element, we have successfully established a UV-assisted CTL sensor for gaseous CO based on g-C3N4 with high sensitivity, selectivity, and stability. UV irradiation can efficiently activate CO molecules and induce the generation of reactive oxygen species (ROS) for CO oxidation. Furthermore, carboxyl groups greatly facilitate the chemisorption of CO on functionalized g-C3N4 nanomaterials, thus enhancing the CTL sensitivity. The influences of experimental conditions and the possible catalytic mechanism of CO on functionalized g-C3N4 have been investigated in detail. Under the optimal experimental conditions, the proposed CTL sensor presents a detection limit (3σ) toward CO of 0.008 µg mL-1, which is much lower than the maximum allowable emission concentration of CO in atmospheric conditions (0.030 µg mL-1). The UV-CTL system is green, sensitive, stable, and low cost, and thus it possesses great potential application in gas sensing.

Chemiluminescence of black phosphorus quantum dots induced by hypochlorite and peroxide.

For the first time, black phosphorus quantum dots (BP QDs) were found to show chemiluminescence (CL) properties in the presence of hydrogen peroxide (H2O2) and hypochlorite (ClO-). Excited phosphorus oxides (HPO) resulting from the oxidation of BP QDs account for CL emission. Taking triacetone triperoxide (TATP) as an example, the potential application of a new CL system was evaluated. This work sheds new light on the characteristics and broader applications of black phosphorus (BP).

Label-Free DNA Assay by Metal Stable Isotope Detection.

The interest in label-free bioassays is increasing rapidly because of their simple procedure and direct information on the interaction between the target molecule and the sensing unit. One of the major obstacles in the application of label-free biosensors is the difficulty to produce stable and reproducible optical, electric, electrochemical, or magnetic properties for the sensitive detection of the target molecules. In this work, we demonstrated a label-free DNA assay, by directly measuring the intrinsic 63Cu and 65Cu stable isotopes inside the double-strand DNA-templated Cu nanoparticles. The experimental conditions, including detection of copper by elemental mass spectrometry, the copper nanoparticles formation parameters, the hybrid chain reaction parameters, and analytical performance, were investigated in detail. The 63Cu signal intensity possesses a linear relation with the concentration of target DNA over the range of 20-1000 pM with a detection limit of 4 pM (3σ). The detection limit of this method is among the most sensitive label-free techniques and also comparable to the lanthanides and Au nanoparticles labeled assays by elemental mass spectrometric detection. The proposed label-free bioassay is simple and sensitive and eliminated the need for optical, electric, electrochemical, or magnetic properties of the sensing unit. To our best knowledge, this is the first report of the label-free bioassay by metal stable isotope detection.

Silicon carbon nanoparticles-based chemiluminescence probe for hydroxyl radical in PM2.5.

A new SiC nanoparticles (SiC NPs)-based chemiluminescence (CL) probe for selective and sensitive detecting of ˙OH has been developed. The radiative recombination of ˙OH-injected holes and electrons in the SiC NPs accounts for the CL phenomenon. Furthermore, the as-developed CL probe has been successfully applied to detect ˙OH in PM2.5.

Highly sensitive cataluminescence gas sensors for 2-butanone based on g-C3N4 sheets decorated with CuO nanoparticles.

A simple and facile ultrasound-assisted and calcining synthesis route was used to synthesize g-C3N4 sheets decorated with CuO nanoparticles (CuO/g-C3N4). On the basis of the XRD, XPS as well as TEM analysis, CuO nanoparticles which have high density and uniformity were evenly dispersed on g-C3N4 sheets to form a heterogeneous composite. The CuO/g-C3N4 composite was fabricated to be a gas sensor for 2-butanone, a common volatile organic compound, based on the interesting cataluminescence (CTL) phenomenon of 2-butanone originating from its catalyzing oxidation on the surface of CuO/g-C3N4 composite. The analytical characteristics of the CTL sensor based on CuO/g-C3N4 composite sensing material for 2-butanone were systematically investigated under the optimal experimental conditions. It demonstrated a fast response and recovery time about less than 2 and 40 s, respectively. The linear range of the 2-butanone gas sensor was 16.11-161.08 µg mL-1 (r = 0.998) and the limit of detection was 11.06 µg mL-1 (S/N = 3).

Transient Cataluminescence on Flowerlike MgO for Discrimination and Detection of Volatile Organic Compounds.

Methodologies for simple and rapid identification of gas compounds are needed in the fields of environmental and security. Here, a new and simple method for the discrimination of gas compounds was designed through an interesting transient cataluminescence (TRCTL) phenomenon on the highly efficient MgO materials. The flowerlike MgO with high CTL activity was controllably synthesized via a facile and time-saving aqueous precipitation route and characterized by scanning electron microscopy, powder X-ray diffractometry, high-resolution transmission electron microscopy, and N2 adsorption measurements, etc. With flowerlike MgO working as the sensing material, the newly developed CTL gas sensor exhibited highly active, ultrafast, and characteristic responses toward many analytes; the TRCTL curves thus were obtained and 10 VOCs have been successfully identified. Parallel experimental results show that the controllable synthesis of flowerlike MgO can greatly enhance the discrimination capacities for VOCs. Further, the TRCTL of CHCl3 and C2H5OC2H5 were taken as typical examples to illustrate the possible sensing mechanism, which could contribute to explaining processes of catalytic oxidations. We expect this novel TRCTL concept will be of practical importance for applications including gas detection, gas discrimination, and research of chemical kinetics processes.

A persistent luminescence microsphere-based probe for convenient imaging analysis of dopamine.

Using probes based on persistent luminescence nanoparticles (PLNPs) is a promising methodology for direct imaging analysis of bio-molecules. In the present work, SrMgSi2O6:Eu0.01,Dy0.02 persistent luminescence microspheres have been synthesized via a simple template method and sunlight could successfully excite their luminescence. Further, a new probe was established based on turn-off of the persistent luminescence emission for detection and optical imaging of dopamine (DA). Mechanistic studies indicated that when the synthesized PL microspheres themselves are alkaline, the PL of the SrMgSi2O6:Eu0.01,Dy0.02 microspheres can be efficiently quenched by DA through electron transfer in the presence of ambient O2. The approach exhibited high convenience by only homogeneously mixing DA and the SrMgSi2O6:Eu0.01,Dy0.02 microspheres. Meanwhile, other phenols, ascorbic acid (AA), and uric acid (UA) were tested and had little interference to the dopamine detection. The current strategy showed the linear range of PL intensity versus concentration was 1.0 × 10(-5)-1.0 × 10(-3) M for DA with a detection limit of 0.78 µM (S/N = 3) and it was successfully applied for imaging and detection of DA in human urine with quantitative recovery (99.6-102.5%).

Amino-Functionalized Metal-Organic Frameworks Nanoplates-Based Energy Transfer Probe for Highly Selective Fluorescence Detection of Free Chlorine.

Novel highly fluorescent NH2-MIL-53(Al) was controllably synthesized by a facile one-step hydrothermal treatment of AlCl3·6H2O and NH2-H2BDC in water with urea as a modulator. The as-synthesized NH2-MIL-53(Al) nanoplates exhibited excellent water solubility and stability. In the present work, it can be found that strong fluorescence of NH2-MIL-53(Al) nanoplates was significantly suppressed after the addition of free chlorine, and a simple sensing system for fast, highly selective direct detection of free chlorine in water was established. Compared with other fluorescent sensors for free chlorine, the present methodology has a comparable detection limit of 0.04 µM (S/N = 3) and a wide detection range of 0.05 to 15 µM. On the other hand, the traditional redox-based fluorescent probes sharply suffered from the interference of MnO4(-), Cr2O7(2-), and other oxidants with stronger oxidation capability than free chlorine while ours overcame this disadvantage. Further research suggests that it is more likely the energy transfer through N-H···O-Cl hydrogen bonding interaction between amino group and ClO(-) ions plays the key role in our system, providing a new and promising platform for free chlorine determination in water quality monitoring.

Simultaneous Determination of Se and Te in Ores by HG-AFS After Online Preconcentration with Nano-TiO2 Immobilized on Silica Gel.

A simple, sensitive and interference-free method was established for simultaneous determination of trace selenium and tellurium in ore samples by HG-AFS, by using nano-TiO2 immobilized on a silica gel packed microcolumn for online preconcentration. Selenium and tellurium were selectively adsorbed to the microcolumn in acidic condition and then completely eluted with 2% (m/v) NaOH solution. The experimental conditions for hydride generation, adsorption, elution and potential interference were investigated in detail. Under the optimum conditions, the detection limits of selenium and tellurium by the proposed method with 180 s sampling time were 4.0 and 3.6 ng · L(-1), with sensitivity enhancement of 20- and 13-fold compared to conventional hydride generation method, respectively. The relative standard deviation (RSD, n=5) of this method for 1 µg · L(-1) Se(IV) and Te(IV) were 0.7% and 2.3%, respectively. This method was applied to determination of selenium and tellurium in several ore samples.