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Direct surface analysis in ambient conditions provides information on the position and chemical composition of an object at the time of investigation. An angled sampling probe is developed in this work for direct analysis in real time (DART) ionization high-resolution mass spectrometry. The DART ion source and the interface were modified for improved surface resolution, increased ion transfer efficiency, as well as enabling two-dimensional surface scanning. The angled probe DART-MS system was used for investigating a variety of food samples including fruit peels, ginseng root, plant leaves and sections of radish. Abundant signals and distinct chemical profiles are obtained in seconds, and spatial distribution of different molecules across the sample surfaces can be observed. In addition, the developed system can quickly identify the chemical changes when the surfaces were treated. The method is capable of directly evaluating food sample surfaces with different shapes, hardness, and conditions, without any sample pretreatments. [Display omitted] • Direct analysis in real time ion source with angled sampling was modified. • Direct surface analysis was achieved in ambient conditions without sample preparation. • Abundant chemical profiles and spatial distribution of molecules were obtained. • Applicable for food surfaces with different shapes, textures, hardness and conditions. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) have been suggested for pancreatic islet repair in Type 1 diabetes mellitus (T1DM). This study aimed to investigate the effect of human umbilical cord MSCs (hUC‐MSCs) transfected with tissue inhibitors of matrix metalloproteinase (TIMP)‐1 on the regeneration of β‐cell islets in vitro and in vivo. hUC‐MSCs were isolated, cultured, and transfected with lentiviruses for the overexpression of hTIMP‐1. An in vitro coculture system of hUC‐MSCs and streptozotocin‐induced islets was established to examine the morphology, apoptosis, and insulin secretion of the cocultured islets. Diabetic mouse models were injected with lenti‐TIMP‐1‐enhanced green fluorescent protein (EGFP)‐hUC‐MSCs to test the effect of hTIMP‐1 on insulin levels and glucose tolerance in vivo. The expression of insulin and glucagon was evaluated by immunofluorescence staining. The results showed that coculture with hUC‐MSCs or Lenti‐TIMP‐1‐EGFP‐hUC‐MSCs improved islet viability rates. Lenti‐TIMP‐1‐EGFP‐hUC‐MSC coculture increased the insulin and C‐peptide secretion function of the cultured islets and increased the secretion of tumor necrosis factor‐β1, interleukin‐6, IL‐10, and hTIMP‐1. hUC‐MSCs, especially those transfected with Lenti‐hTIMP‐1‐EGFP, showed a strong protective effect in diabetic mice by alleviating weight loss and improving glucose and insulin metabolism. In addition, transplantation rescued islet histology and function in vivo. The overexpression of TIMP‐1 by hUC‐MSCs seems to exert beneficial effects on pancreatic islet cells. In conclusion, this study may provide a new perspective on the development of hUC‐MSC‐based cell transplantation therapy for T1DM. [ABSTRACT FROM AUTHOR]

[Display omitted] • A framework which unitedly simulates the regeneration and power generation units is built. • Total efficiency of REDHE is divided into the respective efficiencies of two units. • A highest energy efficiency of 7.13% is obtained at RED temperature of 50 ℃. • Initial salinity in the REDHE should be optimized to obtain a higher efficiency. Reverse electrodialysis heat engine (REDHE) emerges great potential to harvest the low-grade heat (LGH) produced during the industrial processes and renewable energy utilizations. In the closed-loop system, the power generation unit converts the salinity gradient power (SGP) to electric energy using the reverse electrodialysis (RED) cells, and the regeneration unit recovers the salinity gradient based on LGH. As two units are in series, the regeneration and power generation units should be collaboratively optimized to achieve a high performance of REDHE. Herein, a framework which can unitedly simulate the both units is built, which enables to divide the total efficiency of REDHE to the respective efficiencies of units. LiBr solution as the working fluid and the effects of initial salt concentration, concentration of the high concentration (HC) solution and temperature in RED cells are considered. Results show that the total efficiencies increase with the concentration of HC solution and the RED temperature due to the production of more chemical energy in the regeneration unit. However, a non-monotonic trend of the total efficiency with the initial concentration is discovered, which increases from 4.91% to 5.42% and then decreases to 4.69% when the initial concentration raises from 20 wt% to 25 wt% and then reaches 30 wt% at RED temperature of 25 ℃. Although enhancing the RED temperature to 50 ℃ leads the total efficiencies increase to 6.25%, 7.13% and 6.38%, respectively, the trend is unchanged. The respective efficiencies of units explain the phenomenon by that a higher salinity can decrease the efficiency of the power generation unit by reducing the ionic selectivity in the RED cells, but enhance the efficiency of the regeneration unit. Therefore, the highest total efficiency reached at initial concentration of 25 wt% is the trade-off between the efficiencies of two units. This study indicates that increasing the concentration of HC solution, the RED temperature, and carefully selecting a compromise initial concentration are helpful to achieve a high energy efficiency in a REDHE. [ABSTRACT FROM AUTHOR]

Highlights • A new orange phosphor GGAON 0.5 :Ce3+ with sufficient red component was synthesized. • No decay in the 10 microsecond is the key feature applied in AC-circuit directly. • Self-packed LED lamp emits warm white light with high rendering index. Abstract Solid solution phosphors Gd 3 Ga 2 (Al 3- y Si y)(O 12- y N y):Ce3+ were synthesized by introducing [Si4++N3–]/[Al3++O2–] co-substitution into the lattice of Gd 3 Ga 2 Al 3 O 12 :Ce3+. Gd 3 Ga 2 Al 3 O 12 :Ce3+, characteristic as outstanding light yield (about 50–60 kPh/ MeV), and has been applied in computer tomography (CT), positron emission tomography (PET) nuclear medical detector, et al. With the increase of y value, the coordination environment around Gd3+(Ce3+) shrinked, which were confirmed by combining techniques of structure refinement, energy- dispersive spectrum, elements distribution mapping. As a result, stronger 5 d orbital nephelauxetic effect (ε c) and bigger 5 d energy level splitting (ε cfs) were induced. Thus resulting in longer wavelength of excitation and emission from Ce3+, and broadening of emission spectra. The typical sample Gd 2.95 Ga 2 Al 2.5 Si 0.5 O 11.5 N 0.5 :0.05Ce3+ (GGASON 0.5 :Ce3+) exhibits sufficient red component and persistent luminescence(>10 ms), enables fabrication of warm white light suited for alternating-current (AC) when combined with blue light chip (460 nm). [ABSTRACT FROM AUTHOR]

The interaction between a luminescent covalent organic framework (COF) and the indoor pollutant NH3 was investigated based on density functional theory and time-dependent density functional theory. The frontier molecular orbitals and electronic configuration showed that the luminescence mechanism of the COF was strongly affected by the hydrogen bond between the COF and NH3. In addition, the calculated hydrogen bond length, infrared (IR) spectra, and proton nuclear magnetic resonance (1H NMR) spectroscopy analysis indicated that the hydrogen bond in the S1 state was enhanced, which is identical to the calculated results of electronic excitation energies. The fluorescence rate coefficient of the COF was reduced when interacting with NH3. The hydrogen bond between the COF and NH3 in the S1 state is critical for the COF luminescence properties, which means that the COF shows potential application in the detection of NH3. [ABSTRACT FROM AUTHOR]

The rare-earth free tunable full-color-emitting Si-BCNO phosphors were synthesized at low temperature (below 800 °C) for 45 min by solid state reaction method using urea, boric acid, polyethylene glycol and silica as raw materials. The prepared samples exhibited single, distinct and broad photoluminescence emission bands varied from blue (470 nm) to red (620 nm) upon excitation at 370 nm by varying the concentrations of Si and sintering temperatures. The decay curves signified that the luminescence was induced by two luminescence centers, related to longer lifetime τ 1 and shorter lifetime τ 2 . The temperature-dependent PL intensity of the phosphor has been also investigated, which performs good thermal stability. It is believed that the Si-BCNO phosphor could be a possible material for multicolor light-emitting diodes. [ABSTRACT FROM AUTHOR]

This article presents a recognition mechanism for nitro-explosives by the luminescent metal-organic framework 1 (LMOF-1) with the aid of density functional theory (DFT) and time-dependent density functional theory (TDDFT). The behavior of hydrogen bonding between the LMOF-1 and nitro-explosives in the S 1 state is closely associated with the fluorescence properties of the LMOF-1. In our research, we calculated the geometric configuration, 1 H NMR and IR spectra of the Complex 2 formed by LMOF-1 and nitrobenzene in the S 0 and S 1 states. The results showed that the hydrogen bond in the S 1 state was increased, which was unfavorable for the luminescence of LMOF-1. Furthermore, the fluorescence rate of LMOF-1 decreased after encapsulating nitrobenzene into it. These calculated results collectively suggest that LMOF-1 is a potential fluorescence sensor for the detection of nitro-explosives. This research was aiming to provide a better understanding of the recognition mechanism by LMOFs for nitro-explosives. [ABSTRACT FROM AUTHOR]

The influence of oxygen molecule on the luminescent properties of a cyclometalated Pt(II) complex Lxp1, was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. Analysis of frontier molecular orbitals and electronic configuration indicated that the highest-occupied molecular orbital of the Lxp1 has a significant mixture of metal Pt (d) as well as 2-phenylpyridine and acetyl acetone( π ). The lowest-unoccupied orbital of the Lxp1 primarily locates on π * of 2-phenylpyridineligands. The emission mechanism of the cyclometalated Pt(II) complex Lxp1 is assigned to the mixing of ligand-to-metal charge transfer and ligand-to-ligand charge transfer. The emission mechanism of the Lxp1–O 2 complex can be attributed to the charge transfer from the oxygen molecule to the luminescent material Lxp1. Our study showed that intermolecular hydrogen bonding between the Lxp1 and oxygen molecule was strengthened by the calculation of electronic excitation, leading to a luminescence-decreasing phenomenon. The calculation of the radiative and non-radiative decay rate constants of the Lxp1 and the Lxp1–O 2 complex demonstrates that the phosphorescence from T 1 -S 0 of the Lxp1 would alter to the internal conversion from T 1 -T 0 of the Lxp1–O 2 complex. This alteration further explains the luminescence quenching phenomenon of the cyclometalated Pt(II) complex Lxp1 after interacting with oxygen molecule. [ABSTRACT FROM AUTHOR]

To find an effective approach that improves nitrogen removal while reducing methane (CH 4 ) emission during the process of wastewater treatment in constructed wetlands (CWs), we conducted a microcosm experiment simulating CWs with two treatments. The first treatment was plant diversity (species richness and identity), and the second treatment was substrate sand particle size (fine sand and coarse sand). Results showed that, (1) the range of CH 4 emission in fine sand microcosms (−8.46 to 21.03 mg CH 4 m −2 d −1 ) was much greater than that in coarse sand (5.06 to 6.85 mg CH 4 m −2 d −1 ); (2) in coarse sand microcosms, plant species richness increased nitrogen removal ( P < 0.05), but did not affect CH 4 emission ( P > 0.05); (3) in fine sand microcosms, species identity surpassed species richness as a key driver of CH 4 emission, and the presence of Oenanthe javanica significantly decreased CH 4 emission, whereas the presence of Rumex japonicus notably increased CH 4 emission ( P < 0.05, respectively); (4) the nitrogen removal in fine sand microcosms was higher than in coarse sand microcosms ( P < 0.05). Results also showed that Phalaris arundinacea monoculture in fine sand microcosms had a high N removal and low CH 4 emission. Overall, we conclude that the best combination of low CH 4 emission and high N removal rates could be achieved in fine sand microcosms with special plant species as P. arundinacea . [ABSTRACT FROM AUTHOR]

There are still some problems in the study of hydraulic fracture (HF) network evolution in cemented naturally fractured reservoirs, such as microseismic mapping showing exaggerated stimulated reservoir volume in some cases. In addition, the dominant role of natural fracture (NF) cementation strength, injection rate, in situ stress difference, NF distribution, and fracture initiation sequence of perforations in synthetically influencing fracture network formation needs to be further studied. For this purpose, a three‐dimensional matrix hexahedral element global coupled 0‐thickness cohesive element hydraulic fracturing model was developed. Results show that each interaction between HF and NF causes HF diameter shrinkage, which increases the propagation pressure of HF. When the cementation strength of the NF is low, the HF tends to deviate toward the tip of the NF to form a complex fracture network. Increasing the injection rate and the number of NFs can significantly enhance the complexity of the HF network, but does not change the HF and NF interaction pattern. The in situ stress differences dominate the morphology of the HF network when the cementation strength of NFs is constant. The stress interference of multiple fractures under segmented fracturing may form "S"‐shaped HFs, and the HFs are difficult to maintain a symmetrical morphology in the direction of the well axis. In addition, some NFs in inactivated damaged zones have developed a certain width geometrically due to the induced effect of HF, but they are still isolated by the low permeability matrix and might only generate some microseismic events. [ABSTRACT FROM AUTHOR]

A series of SrSiAl2O3N2:Eu2+ (0.005 ≤x≤ 0.05) phosphors were successfully synthesized through a pressureless, facile, and efficient solid state route. The crystal structure, band structure, and their photoluminescence and cathodoluminescence properties were investigated in detail. The phosphors exhibit rod shape morphology with a uniform Eu2+ distribution. Under n-UV excitation the emission spectra shift from 477 to 497 nm with an increase of Eu2+ concentration. The concentration quenching mechanism of Eu2+ emission was dominated by the dipole–dipole interaction. The thermal stability is comparable to that of the commercial Ba2SiO4:Eu2+ phosphor. The phosphor also exhibits high current saturation and high resistance under low voltage electron bombardment. All the results indicate that the SrSiAl2O3N2:Eu2+ phosphors can be considered as candidates for application in both white LEDs and FEDs. [ABSTRACT FROM AUTHOR]

The promising green oxynitride phosphor, Ba3−xMgxSi6O12N2:Eu2+ was synthesized by the solid-state reaction method. The effect of Mg2+ doping on the structure and photoluminescence (PL) properties of Ba3Si6O12N2:Eu2+ was investigated systematically. The results reveal that the phosphor retains the single phase of Ba3Si6O12N2, with the lattice expanding upon increasing the Mg2+ concentration, in an appropriate range. This suggests that a large portion of Mg2+ enters into the interstitial sites of the crystal lattice. At a certain concentration, Mg2+ doping can greatly enhance the absorption and PL intensity and decrease the full widths at half maximum (FWHM) of Ba3Si6O12N2:Eu2+ phosphors. The green phosphor Ba2.87Eu0.1Mg0.03Si6O12N2 exhibited a small thermal quenching, which remained 82% of the initial emission intensity when measured at 150 °C. The quantum efficiency measured at 400 nm excitation was 38.5%. All the results indicate that the solid solution Ba3−xMgxSi6O12N2:Eu2+ can be a good candidate for phosphors applicable in n-UV LEDs for solid-state lighting. [ABSTRACT FROM AUTHOR]

Using the solid-state reaction method, Ce3+, Tb3+-coactivated Si5 AlON7 ( Si6− z Al z O z N8− z, z = 1) phosphors were successfully synthesized. The obtained phosphors exhibit high absorption and strong excitation bands in the wavelength range of 240-440 nm, matching well with the light emitting-diode ( LED) chip. The ET from Ce3+ to Tb3+ ions in Si5 AlON7: Ce3+, Tb3+ has been studied and demonstrated by the luminescence spectra and decay curves. Moreover, the phosphors show tunable emissions from blue to green by tuning the relative ratio of the Ce3+ to Tb3+ ions. Thermal quenching properties of Si5 AlON7: Ce3+, Tb3+ had also been investigated and the quenching temperature is ~190°C. These results show that Si5 AlON7: Ce3+, Tb3+ could be a promising candidate for a single-phased color-tunable phosphor applied in UV-chip pumped LEDs. [ABSTRACT FROM AUTHOR]

Abstract: Bi3+ doped Ca12Al14O32Cl2 series were successfully synthesized by conventional solid-state reaction method and their luminescence properties have been investigated in detail. Crystallographic parameters of the refinement structure with cubic space group I-43d were obtained by XRD refinement as a =12.0183(3)Å and V (cell volume)=1735.93(1)Å3. The resulting phosphors absorb ultraviolet (UV) light (240–400nm) and show a single intense broad emission band in the wavelength range of 400–600nm with maximum intensity at 483nm. The Commission Internationale de 1’Eclairage (CIE) chromaticity coordinates are about x =0.185, y =0.306. Thus, the novel light blue-emitting phosphor Ca12Al14O32Cl2:Bi3+ could be potentially applied in UV white light-emitting diodes. [Copyright &y& Elsevier]

Abstract: Rare-earth-doped β-SiAlON phosphors, with the compositions of Si6− z Al z O z N8− z :xRe (z =1, Re=Sm or Dy, 0.01⩽ x ⩽0.05), were prepared by a solid-state reaction at high temperature. The photoluminescence properties were investigated as functions of the rare earths (i.e., x) concentration. In β-SiAlON:Sm2+, broad 4f 55d 1 →4f 6 emission and line 5 D 0 → 7 FJ emission were observed at room temperature. The characteristic 4 F 9/2 →6 H 15/2 (blue) and 4 F 9/2 →6 H 13/2 (yellow) transitions of Dy3+ were detected in the emission spectra. And the thermal quenching properties of β-SiAlON:Sm2+ and β-SiAlON:Dy3+ were investigated. [Copyright &y& Elsevier]

Abstract: β-SiAlON:Ln3+ (Ln=Yb/Ho, Yb/Er) microparticles with up-conversion (UC) luminescence properties were successfully synthesized via a solid-state reaction method by employing Si3N4 (nanopowder), Al2O3 (nanopowder) and rear-earth oxides. The results show that the β-SiAlON:Ln3+ microparticles have a size ranging from 100 to 400nm. Under the 980nm NIR laser excitation, Yb/Er and Yb/Ho codoped samples exhibit UC luminescence centered at 658 and 660nm, respectively. The power dependency and the dynamics of the UC luminescence confirm the existence of two-photon UC processes in Yb/Er and Yb/Ho codoped samples respectively, and the UC mechanisms were given. [Copyright &y& Elsevier]

Abstract: A novel ZrO2:Sm3+,Sn4+ phosphor is synthesized by solid state reaction. The ZrO2:Sm3+ does not show afterglow. But, after doping Sn4+, intense red afterglow luminescence is firstly observed in ZrO2:Sm3+,Sn4+ and it can last more than 1000s at maximum. The afterglow decay curves of ZrO2:Sm3+,Sn4+ are fitted by three exponential components and the decay process consists of initial fast, intermediate and slow decay. The thermoluminescence indicates that the Sn4+ ions induce suitable traps with the depth of 0.436eV and result in efficient afterglow luminescence of ZrO2:Sm3+,Sn4+. The thermoluminescence filling and fading experiments further confirm the important role of the proper shallow traps induced by doping Sn4+ on the afterglow of ZrO2:Sm3+,Sn4+. [Copyright &y& Elsevier]

Large quantities of hexagonal boron nitride ( h-BN) nanoplates with hexagonal morphologies have been successfully synthesized by a simple two-step route without using any template or catalyst, including combustion synthesis and then annealing processes. The phase content, morphology, and optical properties of the products have been characterized. It reveals that the obtained products are pure and of high crystallinity. The UV-vis absorption spectrum indicates that the h-BN nanoplates have an optical band gap of ~6.07 eV. Strong violet-blue photoluminescence ( PL) emission with a broad band ranging from 400 nm to 475 nm has been observed, indicating that the nanoplates as-grown by this simple route are promising for application in nanosize optical devices ( LEDs, blue-light source, UV detector, etc.). The phonon lines features are obviously found in the PL spectra, the phonon frequency involved in these transitions is consistent with the B-N E2g vibrational mode, which has been measured by the Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Lead exposure is one of major public health problems. The aim of this study was to examine in vitro the effect of lead on lymphocyte intracellular Ca2+ ([Ca2+]i). Methods: Lymphocytes were separated from mice spleen and treated with three doses of PbCl2 (1, 10 and 100μmol/L). [Ca2+]i was measured in a Thermo Labsystems Fluoroskan Ascent after loading the cells with Fura2-AM probe. Results: The lymphocyte [Ca2+]i in 10 and 100μmol/L PbCl2 groups increased to the highest level after 10min of lead exposure (P <0.05). After 1h of lead exposure, however, lymphocyte [Ca2+]i levels were not statistically different from that in control group cells (P >0.05). Removal of Ca2+ from external solution did not significantly affect the PbCl2-induced lymphocyte [Ca2+]i. PbCl2 increased the [Ca2+]i under both normal Ca2+ and Ca2+-free conditions. With pretreatment of calmodulin (CaM) antagonist W7, lymphocyte [Ca2+]i levels were still high, but [Ca2+]i levels were not as high as those in the absence of W7. Conclusion: When the lymphocytes were exposed to PbCl2 ranging from 1 to 100μmol/L, the lymphocyte [Ca2+]i level was increased, but the increase appeared reversible. CaM may play a role in the process of the effect of lead on the lymphocyte [Ca2+]i. [Copyright &y& Elsevier]

The fluorescence quenching mechanism of the HPHN-CQDs in the presence of Cu2+ ions. • HPHN-CQDs are prepared using pure HPHN with known molecular and crystal structures. • HPHN-CQDs exhibit an excellent luminescent recognition toward Cu2+ ions with a detection limit of 4.8 nM. • The orbital interaction diagram indicated that the presence of Cu2+ can affect the luminescence behavior of HPHN. • The electron is transferred from the excited HPHN to the 3d orbital of Cu2+. • The fluorescence rate constant of HPHN-Cu2+ was substantially decreased compared with that of HPHN. A combination of experimental and computational methods was used to study the Cu2+ ions recognition by 9-hydroxyphenal-1-one carbon quantum dots (HPHN-CQDs). HPHN-CQDs were proved to be an efficient fluorescent probe that can detect Cu2+ ions with high selectivity and sensitivity, and the detection limit was 4.8 nM. We performed a detailed analysis of the fluorescence quenching mechanism of HPHN-CQDs by means of density functional theory (DFT) and time-dependent density functional theory (TDDFT). The orbital interaction diagram indicated that the presence of Cu2+ can affect the luminescence behavior of HPHN by changing its orbital distribution. In addition, the electron was transferred from the excited HPHN to the 3d orbital of Cu2+, which would hinder the recombination of electron-hole pairs and promote the fluorescence quenching of HPHN-CQDs. The photophysical process revealed that the fluorescence rate constant of HPHN-Cu2+ was substantially decreased compared with that of HPHN, which is consistent with the experimental results. [ABSTRACT FROM AUTHOR]

Highlights: [•] Novel red phosphor Ca12Al14O32Cl2:Eu3+ was prepared by solid-state reaction. [•] Excitation spectra suggested an obvious absorption in near-ultraviolet region. [•] Under 392nm excitation, the phosphors exhibited a red emission at 614nm. [•] Ca12Al14O32Cl2:Eu3+ could be potentially applied in near UV white LEDs. [Copyright &y& Elsevier]

Novel Ca 1.96 (B 1- y Si y)(O 3- y N y)Cl:0.04Eu2+ phosphors were designed and synthesized by introducing [Si4++N3−]/[B3++O2−] co-substitutions into Ca 2 BO 3 Cl:Eu2+ lattice. Fourier Transform Infrared Spectroscopy (FTIR) show that typical planar [BO 3 ]3− units gradually transformed into [BO 4 ]5− units with the increase of y , which was firstly realized in luminescence materials. Uneven expansion of cell parameters a,b, and c were confirmed by the combination of X-ray diffraction spectra (XRD) and results of Rietveld refinement. Structure variation caused smaller centroid shift (ε c) and 5 d energy level splitting (ε cfs), inducing the narrowing of excitation spectra (y = 0 → y = 0.2, 168 → 144 nm) and blue-shift of emission spectra (y = 0 → y = 0.2, 582 → 525 nm). Excellent thermal stability (6% loss at 150 °C) was obtained, which resulted from more covalent bonding. Using the combination of representative sample CBSOCN 0.2 : 0.04Eu2+ and red K 2 SiF 6 :Mn4+ in a blue LED driven lamp, white light with high CRI ~92.8 and color temperature closed to the summer sun (5770 K) was obtained. Unlabelled Image • [Si4++N3−]/[B3++O2−] co-substitution was applied to synthesize the Ca 2 (B 1- y Si y)(O 3- y N y)Cl:Eu2+ series. • Luminescence color change from yellow to green with the increase of y. • Thermal stability of samples increased with the increase of y. • White light with high CRI can be synthesized by using the optimal sample CBSOCN 0.2 : 0.04Eu2+. [ABSTRACT FROM AUTHOR]

Luminescent covalent organic frameworks (COFs) as fluorescent sensor materials provide a distinct advantage over other materials. In this work, we investigated the hydrogen bonding between the luminescent COF Ph-An-COF and formaldehyde in its excited electronic state by using density functional theory and time-dependent density functional theory to determine whether this type of COF can be used for formaldehyde detection. Hydrogen bonding significantly changed the nature of the frontier orbital and the luminescent properties. Our study reveals that the hydrogen bonding was strengthened in the excited state and the fluorescence rate coefficient was significantly reduced, which is not favorable for the luminescence of this type of COF and would lead to a luminescence decrease or quenching phenomenon. Therefore, this type of luminescent COF can be used as a potential chemical sensor to detect formaldehyde. This work provides an insight into the design of luminescence covalent organic frameworks. [ABSTRACT FROM AUTHOR]

Formaldehyde is the main cause of indoor pollution. In this research, we investigated the mechanism that the covalent organic framework (COF) identifies formaldehyde applying density functional theory (DFT) and time-dependent (TD) DFT approaches. On one hand, the calculation results of the geometric parameters, IR spectra, as well as 1H-NMR chemical shifts for protons that associated with the hydrogen bonding formation together with the electronic transition energies verified that the furcate hydrogen bonding formed between the COF and formaldehyde is enhanced in the excited S1 state and it is not beneficial to luminescence of the COF. On the other hand, excitingly, our further calculation results of the fluorescence rate coefficients also revealed that the strengthened hydrogen bonding behavior in S1 state caused an efficiently weakened luminescent phenomenon compared with that of the COF. Therefore, this analysis method, which qualitative collaborates with quantitative theoretically, demonstrates the possibility that the COF could be served as a sensor to detect formaldehyde.The luminescence of the Covalent Organic Framework can be greatly weakened after the addition of formaldehyde. [ABSTRACT FROM AUTHOR]

Ca12Al14O32Cl2:xBi3+ (0.005 ≤ x ≤ 0.7) phosphors are synthesized by solid state reaction of CaCO3, Al2O3, SiO2, NH4Cl, and Bi2O3 (air, alumina crucible, 1150 °C, 10 h). [ABSTRACT FROM AUTHOR]

In different geological and engineering conditions, it is important to study the stress interference of multiple fractures and interaction of natural fractures in "well factory" fracturing to improve the complexity of fracture networks. For this purpose, a 2D, coupled stress-seepage-damage field cohesive model with random propagation of hydraulic fracture was developed, and a random function was used to simulate the natural fractures distribution in a real reservoir. Orthogonal test was designed to investigate the geological and engineering parameters impacting the evolution of zipper fracturing and modified zipper fracture networks. The results show that in naturally fractured reservoirs, hydraulic fracture can open natural fractures and promote the formation of complex fracture networks by combined, induced manner. Higher stress differences lead to simpler fracture networks and straighter hydraulic fracture propagation paths; When pre-existing natural fracture is longer, the propagation direction of hydraulic fracture is more likely to be paralleled with natural fracture; However, the stress shadow effect of multiple fractures may potentially lead to failure of some hydraulic fracture initiation. In addition, the fracture initiation sequence of multiple fractures has a significant effect on the evolution of the fracture networks. The results of the study have important significance for parameter optimization of well factory fracturing in naturally fractured reservoirs. [ABSTRACT FROM AUTHOR]

This paper investigates the luminescent properties of luminescent metal-organic framework (LMOF) [Zn 2 (oba) 2 (bpy)], and its selectivity for the detection of nitro-explosives via fluorescence quenching, using the density functional and time-dependent density functional theories. The luminescent mechanism of the LMOF follows the electron transfer from ligand to ZnO quantum dot. The hydrogen bondings formed between LMOF and electron-withdrawing nitro-explosives as well as electron-donating aromatic compounds have different influences on the luminescent mechanism of the LMOF. The hydrogen bonding in the excited state was investigated to display the relationship between hydrogen bonding and fluorescence. [ABSTRACT FROM AUTHOR]

Background: Newborn screening (NBS) has been implemented for neonatal inborn disorders using various technology platforms, but false-positive and false-negative results are still common. In addition, target diseases of NBS are limited by suitable biomarkers. Here we sought to assess the feasibility of further improving the screening using next-generation sequencing technology.Methods: We designed a newborn genetic sequencing (NBGS) panel based on multiplex PCR and next generation sequencing to analyze 134 genes of 74 inborn disorders, that were validated in 287 samples with previously known mutations. A retrospective cohort of 4986 newborns was analyzed and compared with the biochemical results to evaluate the performance of this panel.Results: The accuracy of the panel was 99.65% with all samples, and 154 mutations from 287 samples were 100% detected. In 4986 newborns, a total of 113 newborns were detected with biallelic or hemizygous mutations, of which 36 newborns were positive for the same disorder by both NBGS and conventional NBS (C-NBS) and 77 individuals were NBGS positive/C-NBS negative. Importantly, 4 of the 77 newborns were diagnosed currently including 1 newborn with methylmalonic acidemia, 1 newborn with primary systemic carnitine deficiency and 2 newborns with Wilson's disease. A total of 1326 newborns were found to be carriers with an overall carrier rate of 26.6%.Conclusion: Analysis based on next generation sequencing could effectively identify neonates affected with more congenital disorders. Combined with C-NBS, this approach may improve the early and accurate identification of neonates with inborn disorders. Our study lays the foundation for prospective studies and for implementing NGS-based analysis in NBS. [ABSTRACT FROM AUTHOR]

Abstract: Yellow-orange oxynitride Ca-α-SiAlON: Eu2+ phosphors with the compositions of Ca0.8Si9.2Al2.8O1.2N14.8: xEu2+ (x =0–0.24) were obtained via carbothermal reduction and nitridation method. Crystallographic parameters of the refinement structure with triclinic space group P31c (159) were obtained by XRD refinement as a = b =7.8859(3)Å, c =5.7336(2)Å, V =308.7915(3)Å3, Z =1. The resulting phosphors can absorb light in the range of 300–500nm efficiently and show a single intense broad emission band in the wavelength range of 500–700nm with maximum intensity at 580–601nm. The chromaticity coordinates of the synthesized Ca-α-SiAlON: Eu2+ phosphors can be tailored by simply controlling the activator concentration. All the results show that Ca-α-SiAlON: Eu2+ phosphors can be a candidate for warm white LEDs. [Copyright &y& Elsevier]

Glycolaldehyde (HOCH2CHO, GA), the simplest molecule containing both hydroxyl and aldehyde groups, is structurally the most elementary member of monosaccharide sugars, which may provide new clues for probing the origin of life on planets like the Earth. Uncovering the existing state of GA in solution systems is an important scientific issue. Generally, methanol is used as the main mobile phase in the liquid chromatography analysis of GA, but the state of GA existing in methanol solution remains unknown, thus making it difficult to analyse GA accurately. Herein, the state and dynamic equilibrium of GA in methanol solution were systematically studied by UV-visible spectroscopy, nuclear magnetic resonance (1H-NMR) spectroscopy, liquid chromatography mass spectrometry (LC–MS) and density functional theory (DFT) calculations. The results demonstrated that the equilibrium component of GA in methanol solution is different from that in aqueous solution and that glycolaldehyde hemiacetal (GAHA) is a dominant component (>90%). Laying the foundation for experimental analysis, the transformation of different components at equilibrium was studied using DFT. The results confirm that hydrogen bonding-induced proton transfer occurs between the components at equilibrium. This work provides an important reference for the analysis of sugars and related compounds in various biochemical reactions. [ABSTRACT FROM AUTHOR]

Carrier screening of Duchenne muscular dystrophy (DMD) has not been widely evaluated. To identify definite DMD female carriers prior to or in early pregnancy, we studied a large population of reproductive age females and provided informed reproductive options to DMD carriers. 37268 females were recruited from the Hangzhou Family Planning Publicity and Technology Guidance Station/Hangzhou Health Service Center for Children and Women, Hangzhou, China, between October 10, 2017, and December 16, 2018. CK activity was measured with follow-up serum DMD genetic testing in subjects with hyperCKemia, defined as CK > 200 U / L. The calculated upper reference limit (97.5th percentile) of serum creatine kinase (CK) for females aged 20-50 years in this study was near the reference limit recommended by the manufacturer (200 U/L), above which was defined as hyperCKemia. 427 females (1.2%) harbored initially elevated CK, among which 281 females (response rate of 65.8%) accepted CK retesting. DMD genetic testing was conducted on 62 subjects with sustained serum CK > 200 U / L and 16 females with a family history of DMD. Finally, 6 subjects were confirmed to be DMD definite carriers. The estimated DMD female carrier rate in this study was 1 : 4088 (adjusting for response rate), an underestimated rate, since only 50% to 70% of DMD female carriers manifest elevated serum CK, and carriers in this study may have been missed due to lack of follow-up or inability to detect all DMD pathogenic variants by current genetic testing. [ABSTRACT FROM AUTHOR]

Red phosphor is indispensable to achieve warm white light in the white light diode (WLED) application. However, the current red phosphors suffer from high cost and harsh synthesis conditions. In this study, an oxide‐based rare‐earth‐free red‐emitting phosphor Li3Mg2NbO6:Mn4+ (LMN:Mn4+) has been successfully synthesized by a simple solid‐state reaction method. The relationship between crystal structure and luminescence was investigated in detail. The site occupancy of the doping Mn4+ ion in the LMN host has been discussed from the point of bond valence sum. How the coordination environment of doping Mn4+ affects the energy level of doping Mn4+ ion has been illustrated via the Tanabe‐Sugano energy‐level diagram. Moreover, warm white light has been obtained using LMN:Mn4+ as compensator to the YAG:Ce3+. [ABSTRACT FROM AUTHOR]

White light-emitting diodes (WLEDs) have been considered as the next generation lighting technology due to their advantages such as high efficiency and environmental friendliness. However, current mainstream WLEDs, which are based on blue chips and the Y3Al5O12:Ce3+ yellow phosphor, suffer from the problem of low color rendering index (CRI). To solve this problem, a yellowish-green phosphor Ca1.5Y1.5Al3.5Si1.5O12:Ce3+ (CYAS:Ce3+) based on the garnet structure has been designed in this study. Its crystal structure, band structure, and luminescence properties have been investigated in detail. CYAS:Ce3+ exhibits efficient and thermal-stable yellowish-green emission. The 5d centroid shift and crystal splitting of the Ce3+ ion in CYAS have been analyzed together with the structure. Moreover, good warm white light with a low correlated color temperature (3210 K), high color rendering index (85.1) and luminous efficacy (88.5 lm W−1) has been obtained by combining CYAS:Ce3+ and the red phosphor CaAlSiN3:Eu2+ with a blue LED chip. [ABSTRACT FROM AUTHOR]

A novel apatite‐based UV‐excited dual‐emitting Ca2Na2La6(SiO4)4(PO4)2O: Eu2+/Eu3+ phosphor (CNL: Eu2+/Eu3+) was designed and successfully synthesized by a solid‐state reaction. Compared with previous reports on this family of materials, a structural study based on DFT calculation exhibited a new consequence that the monovalent ions in this system are more inclined to occupy the seven‐coordinate cationic sites rather than the nine‐coordinate sites. This result was confirmed by the structural refinement and high‐resolution transmission electron microscopy (HRTEM) data. Due to the coexistence of Eu2+ and Eu3+ dopants in the material, under 345 or 392 nm excitation, CNL: 0.02Eu2+/Eu3+ exhibited a green Eu2+ emission band (528 nm) and red Eu3+ emission peaks (around 618 nm). The application potential of CNL:0.02Eu2+/Eu3+ in luminescent thermometry was studied by exploiting the temperature sensitivity of the fluorescent intensity ratio (green/red) at different temperatures. It was found that, under 345 nm excitation, the fluorescent intensity ratio of CNL: 0.02Eu2+/Eu3+ displayed linear correlation over the temperature range of 298 to 473 K with a high sensitivity of 2.82%K−1. Additionally, the emission color of the CNL: 0.02Eu2+/Eu3+ sample under UV lamp (254 and 365 nm) excitation showed an obvious change (from green to red) as the temperature increased from 298 to 473 K (from green to red). These results indicated that CNL: Eu2+/Eu3+ can serve as an excellent visual luminescent ratiometric thermometer. Furthermore, this work provides a novel reference for developing high‐performance luminescence temperature‐sensing materials. [ABSTRACT FROM AUTHOR]

The present study aimed to identify the molecular mechanism of acute lymphoblastic leukemia (ALL), and explore valuable prognostic biomarkers for relapsed ALL. Gene expression dataset including 59 samples from ALL survivals without recurrence (good group) and 114 samples from dead ALL patients died of recurrence (poor group) was downloaded from TCGA database. The differentially expressed genes (DEGs) were identified between good and poor groups, followed by pathway and functional enrichment analyses. Subsequently, logistic regression model and survival analysis were performed. In total, 637 up- and 578 down-regulated DEGs were revealed between good and poor groups. These DEGs were mainly enriched in functions including transcription and pathways like focal adhesion. Genes including alpha-protein kinase 1 (ALPK 1), zinc finger protein 695 (ZNF695), actinin alpha 4 (ACTN4), calreticulin (CALR), and F-Box and leucine rich repeat protein 5 (FBXL5) were outstanding in survival analysis. Transcription and focal adhesion might play important roles in ALL progression. Furthermore, genes including ALPK1 , ZNF695 , ACTN4 , CALR , and FBXL5 might be novel prognostic genes for relapsed ALL. [ABSTRACT FROM AUTHOR]

In recent years, the rare-earth elements in white light-emitting phosphors have a problem of increased demand and high price. To overcome these disadvantages, defects have been considered to act as new efficient luminescent centers to replace rare-earth elements. In this work, a rare-earth free self-activated orange light emitting phosphor of single-phase magnesium boron nitride, Mg3BN3, was successfully designed and synthesized by a relatively simple solid-state reaction. Its crystal structure and electronic structure have been measured using Rietveld refinement on the basis of X-ray diffraction data and density functional theory (DFT). The results show that Mg3BN3 crystallizes in a centrosymmetric hexagonal phase with plenty of N=B=N double bonds and has a direct bandgap. The SEM and TEM images and Raman spectra exhibit the sample's good dispersibility and great crystallinity. Under excitation at 397 nm, a broad emission band with orange light emission peaked at 617 nm can be obtained. It is speculated to result from the defect energy levels formed by vacancies, which can also lead to tunability of the emission peak at about 100 nm. The thermal quenching shows that Mg3BN3 at 200 °C still has more than 40% of the initial intensity at room temperature. All these results indicate that the self-activated light emitting phosphors of Mg3BN3 are a potential candidate for n-UV LED applications. [ABSTRACT FROM AUTHOR]

The live-attenuated measles virus (MV) vaccine based on the Hu191 strain has played a significant role in controlling measles in China. However, it has considerable adverse effects that may cause public health burden. We hypothesize that the safety and efficacy of MV vaccine can be improved by altering the S-adenosylmethionine (SAM) binding site in the conserved region VI of the large polymerase protein. To test this hypothesis, we established an efficient reverse genetics system for the rMV-Hu191 strain and generated two recombinant MV-Hu191 carrying mutations in the SAM binding site. These two mutants grew to high titer in Vero cells, were genetically stable, and were significantly more attenuated in vitro and in vivo compared to the parental rMV-Hu191 vaccine strain. Importantly, both MV-Hu191 mutants triggered a higher neutralizing antibody than rMV-Hu191 vaccine and provided complete protection against MV challenge. These results demonstrate its potential for an improved MV vaccine candidate. [ABSTRACT FROM AUTHOR]

RTT is a neurodevelopmental disorder characterized by growth regression, motor dysfunction, stereotypic hand movements, and autism features. Typical Rett syndrome (RTT) is predominantly caused by mutations in X-linked MeCP2 gene which encodes methyl-CpG-binding protein 2 (MeCP2). The brain-abundant MeCP2 protein mainly functions as a transcriptional regulator for neurodevelopment-associated genes. Specific functions of MeCP2 in certain neuron types remain to be known. Although cholinergic system is an important modulating system in brain, how MeCP2 in cholinergic neurons contribute to RTT has not been clearly understood. Here we use a mouse model with selectively activated endogenous MeCP2 in cholinergic neurons in otherwise MeCP2 stop mice to determine the cholinergic MeCP2 effects on rescuing the RTT-like phenotypes. We found cholinergic MeCP2 preservation could reverse some aspects of the RTT-like phenotypes in mice including hypolocomotion and increased anxiety level, and delay the onset of underweight, instead of improving the hypersocial abnormality and the poor general conditions such as short lifespan, low brain weight, and increasing severity score. Our findings suggest that selective activation of cholinergic MeCP2 is sufficient to reverse the locomotor impairment and increased anxiety-like behaviors at least in early symptomatic stage, supporting future development of RTT therapies associated with cholinergic system. [ABSTRACT FROM AUTHOR]

Objectives: This is a population based descriptive study that examined the trends in childhood mortality among under five children and the major causes under five mortality in Zhejiang Province, China. Methods: A population-based survey was conducted through a province-level surveillance network. The mortality rate and leading causes of death for children under 5 years of age were analyzed. The trend in the mortality rate for children under five and cause-specific mortality rates were analyzed by chi-square with SPSS 13.0 software. Results: In Zhejiang Province, during 1997-2012, mortality rates in neonates, postneonatal infants, and children under 5 years were reduced by 64.2% (from 7.85 to 2.81 per 1000 livebirths), 66.7% (from 12.73 to 4.24 per 1000 livebirths), and 63% (from 15.76 to 5.85 per 1000 livebirths), respectively. The mortality rates in children under 5 years of age decreased by 59.5% (from 11.09 to 4.49 per 1000 livebirths) and 65.8% (from 19.30 to 6.61 per 1000 livebirths) in urban and rural areas, respectively. Prematurity/low birth weight and congenital heart disease were in the top five causes of death in children under 5 years of age during 1997-2012. Conclusions: Zhejiang province has achieved great progress in the reduction of mortality rates in children under five-years-old during the past two decades. The future tasks on reduction of mortality rate still rely on how to improve the management of premature birth/low birth weight, reduce birth defects and prevent accidental deaths in Zhejiang Province. [ABSTRACT FROM AUTHOR]

As one kind of sounds, human voices are important for language acquisition and human–infant relations. Human voices have positive effects on infants, e.g., soothe infants and evoke an infant's smile. Increased left relative to right frontal alpha activity as assessed by the electroencephalogram (EEG) is considered to reflect approach-related emotions. In the present study, we recorded the EEG in thirty-eight 2-month-old infants during a baseline period while listening to sounds, i.e., human voices. Infants displayed increased relative left frontal alpha activity in response to sounds compared to the baseline condition. These results suggest that sounds can elicit relative left frontal activity in young infants, and that this approach-related emotion presents early in life. [ABSTRACT FROM AUTHOR]

Ca0.8Si9.2Al2.8O1.2 N14.8:xEu2+ (x = 0-0.24) phosphors are prepared by the carbothermal reduction and nitridation method starting with stoichiometric mixtures of CaCO3, Al2O3, Si3N4, Eu2O3, and high purity activated charcoal (alumina crucible, N2 gas flow, 1600 °C, 4 h). [ABSTRACT FROM AUTHOR]

Abstract: A series of white-light-emitting NaSrPO4:Eu2+, Mn2+ phosphors were successfully synthesized by solid-state reaction and their photoluminescence properties were investigated. The NaSrPO4:Eu2+, Mn2+ phosphor system exhibits a broad excitation band in the wavelength range of 250–420nm, which is well-matched with ultraviolet (UV) light-emitting-diode (LED) chips (typically 365nm). As a result of fine-tuning of the emission composition of the Eu2+ and Mn2+ ions, warm-white-light emission can be realized in a single host lattice under 365nm excitation. Efficient resonant energy transfer from the Eu2+ to Mn2+ ions has been observed. The energy transfer efficiency and critical distance were calculated. The results indicate that the developed phosphor can be used as a potential candidate for white LEDs. [Copyright &y& Elsevier]

Abstract: Background: Some studies find delayed development of the auditory brainstem in preterm infants, but others do not. Aim: To compare auditory brainstem responses (ABRs) in healthy preterm and term infants depending on sex and gestational age (GA). Methods: Participants were 111 preterm (27–36weeks GA) and 92 term (37–41weeks GA) infants. ABR tests were conducted at 6weeks (corrected age if preterm). Results: There were no overall differences between term and preterm groups in ABRs. However, males showed longer latencies for waves III, V, and I–III, III–V, and I–V intervals and smaller amplitudes for wave III and V than females in both preterm and term groups (all p values≤.01). A 3-way interaction between group, sex, and GA (p <.05) showed that preterm males with later GA had longer wave I–V interval, whereas term females with later GA showed shorter wave I-V interval. Growth velocity predicted wave I–V interval in preterm infants, controlling for other factors (male: p =.07, female: p <.05). Conclusion: ABRs in preterm and term infants were similar at 6weeks (corrected age if preterm), but males had less advanced ABRs than females. More rapid growth predicted less mature ABR in later GA preterm infants in this setting where they were unlikely to receive extra iron. The roles of GA, growth, and iron balance in ABR development warrant further study. [Copyright &y& Elsevier]

The aim of the study was to evaluate the role of flow cytometric immunophenotyping (FCI) as a rapid diagnostic tool for pediatric malignancy in serous cavity effusions (SCEs). FCI results for 103 SCEs in a pediatric population were compared with retrospective clinical outcomes (RCOs). Among 41 patients assessed as having malignancies by RCO, 36 patients were diagnosed with lymphoma ( n =25), acute myeloid leukemia ( n =2), neuroblastoma ( n =8) and retinoblastoma ( n =1) by FCI, respectively. The sensitivity and specificity of FCI for detecting neoplastic cells were 87.8% and 98.4%, respectively. The concordance of FCI data with final diagnoses of the patients was 94.2%. FCI data for lymphoma was concordant with the final diagnosis in 89.3% of cases. When Hodgkin lymphoma was excluded, the overall correlation increased to 96.1%. FCI is a useful tool for rapid and reliable diagnosis of pediatric non-Hodgkin lymphoma in SCE samples and also to suggest the presence of non-lymphoid malignancies, especially neuroblastoma. [ABSTRACT FROM AUTHOR]

We aimed to investigate the effects of high-fat and high-energy (HFHE) diets on the hepatic expression of cytochrome P-450 3A (CYP3A) in developing female rats. The pups of the dams fed with the standard diet were defined as the NN group and those fed the HFHE diet were defined as the NH group. The mRNA and protein expression, the protein localization and activity was determined. The mRNA expression of CYP3A1 on day 3 in the NH group were higher versus NN groups (p < 0.05) and the expression of the NH group on days 28 and 56 were lower versus the NN group (p < 0.01). CYP3A1 immunolabeling had a zonal-restricted expressions pattern on day 28 and after in the NN groups, while the obvious zonal expression pattern was observed in the NH group on day 84. The mean activity for the NH groups on days 3, 7, 14 and 28 was higher versus the NN groups (p < 0.05). On day 84, the activity was lower for the NH group versus the NN group (p < 0.05). Our findings provide a basis for further studies on appropriate medication regimen in obese children. [ABSTRACT FROM AUTHOR]

Previous studies of auditory recognition memory in sleeping newborns reported 2 event-related potential (ERP) components, P2 and negative slow wave (NSW), reflecting voice discrimination and detection of novelty, respectively. In the present study, using high-density recording arrays, ERPs were acquired from 26 2-month-old awake infants as they were presented with a familiar and unfamiliar voice (i.e., mother and stranger) with equal probability. In addition to P2 and NSW, we observed a positive slow wave (PSW) over the right temporo-parietal scalp, indicating memory updating. Our study suggests that infants appear to have the capacity to encode novel stimuli as early as 2 months of age. [ABSTRACT FROM PUBLISHER]

Turner syndrome (TS) is a chromosomal abnormality, of which the presence and impact of coexisting psychiatric morbidity has received little attention. The present report describes an adolescent with mosaic karyotype TS who had major depressive disorder with the predisposing cause of psychosocial burden, and relieved with the treatment of sertraline and complete remission with combined use of estradiol valerate. The report suggests us to pay more attention on the mood disorders in children with TS, especially in adolescents. For treatment aspect, medications for improving the puberty development and short stature should be added to in addition to antidepressants if they had mood disorders. [ABSTRACT FROM AUTHOR]

[Display omitted] • CQDs were synthesized via coal tar pitch with ozone oxidation method. • The method provides advantages of low-cost, convenience, and environmentally attractive. • CQDs showed a highly sensitivity and selectivity in detection of Fe3+ ions. • CQDs can be used in fluorescence imaging of cells. Carbon quantum dots (CQDs) emerging as newcomers of carbon nanoparticles exhibit fascinating electro-optical properties, and thereby have been widely used in many fields. Herein, we present a new facile, economical and environmentally attractive strategy for the preparation of CQDs via one-step ozone (O 3) treatment of coal tar pitch (CTP). CQDs prepared by this approach exhibit a narrow size distribution between 3–7 nm, and CQDs with a diameter of 4.8 nm accounts for approximately 42.8 %. CQDs were investigated as fluorescent probes for the detection of metal ions, and demonstrated highly sensitive and selective detection of Fe3+ ions. A calibration curve displayed a linear response over the range of 0–9 μM and a detection limit of 0.02 μM (1.12 ppb). Moreover, the photoluminescence performance of the CQDs/Fe3+ complex could be recovered with the addition of EDTA, indicating a great potential for applications of this unique fluorescent CQDs in the detection of Fe3+. Finally, the experiments of CQDs in cell imaging confirmed that the CQDs can be used as potential fluorescent probes in biological imaging, cell labeling with strong luminescence and low toxicity. [ABSTRACT FROM AUTHOR]