Search

Cryogenic temperature sensors play significant roles in manufacturing, metallurgy, and aerospace. Metal-organic frameworks (MOFs) as emerging crystal materials exhibited inherent advantages as fluorescence temperature sensors and researchers have shifted their focus toward incorporating MOFs materials into mixed matrix membranes (MMMs) for broader practical applications. However, the poor interfacial compatibility between MOFs particles and the polymer matrix would cause aggregation-induced fluorescence quenching and reduced energy transfer efficiency, thereby compromising temperature sensing performances. Herein, we adopt a post-synthetic copolymerization strategy to realize an interfacial-compatible membranous ratiometric luminescent thermometer based on the emissions of ligands and lanthanide ions. Benefiting from the controllable covalent cross-linking structures, the designed polyMOF membrane exhibited excellent interfacial compatibility and avoided MOFs irregular morphology agglomeration and phase separation, which contributed to outstanding fluorescence temperature sensing performance with excellent sensitivity ranging from 0.300 to 0.745 %·K−1 within the temperature range of 80–300 K, superior to recent reported MOFs-based thermometers. This research presents a promising approach for the design and fabrication of interfacial compatible MOFs-based membranes with excellent fluorescence temperature sensing properties, advancing the understanding of structure-property relationships and accelerating the practical applications. [Display omitted] • A polyMOF membrane through a covalently cross-linked copolymerization strategy. • This polyMOF membrane exhibited excellent interfacial compatibility. • This polyMOF membrane exhibited outstanding fluorescence temperature sensing performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The subtribe Pemphredonina (Hymenoptera: Crabronidae) in China is taxonomically studied. • One species is described and illustrated as new Passaloecus frontirugatus Bashir and Ma, sp. nov. • Several species are recognized with six new records for China. • A key to the Chinese species of the genus Diodontus and Passaloecus is given and updated, respectively. • Distributional maps of Chinese species are also presented. In this revision of the subtribe Pemphredonina (Crabronidae: Pemphredoninae: Pemphredonini) from China, we reported several species present in respected subtribe, out of which one species is new to science Passaloecus frontirugatus Bashir and Ma, sp. nov., and six species are recorded for the first time from China, including Polemistus palawanensis Tsuneki, Diodontus insidiosus Spooner, Diodontus handlirschi Kohl, Diodontus tiemudzhin Tsuneki, Diodontus spinicerus Kazenas, and Diodontus kuroo Tsuneki. A key to genera and the species of Diodontus and Passaloecus from China is also provided. Distributional records from China of each genus are also given. [ABSTRACT FROM AUTHOR]

Vitamin B 6 (VB 6) is a water-soluble vitamin, which plays an important role in amino acid metabolism and cell maintenance as a coenzyme of amino conversion. Developing a highly sensitive and selective sensor for VB 6 is still a huge challenge. Herein, a luminescent Zn-MOFs (ZnL) with the ligand 4,4'-(1H,1′H-[2,2′-biimidazole]-1,1′-diylbis(methylene)) dibenzoic acid (H 2 L) was designed for analyzing VB 6. The presence of uncoordinated N atoms in ZnL can provide action sites for VB 6 molecule, therefore, ZnL can be applied to specific detection of VB 6 molecule. ZnL exhibits a strong emission spectrum at 390 nm when excited at 300 nm, which realizes the fluorescence quenching detection of VB 6 in aqueous solution. Furthermore, the detection of VB 6 with high sensitivity and selectivity can be obtained even in the presence of common biomolecules. The linear range for VB 6 detection was observed in the concentration range from 5 to 100 μM with a low limit of detection of 0.76 μM. Hence, ZnL has promising application potential for determination of VB 6 in practical applications. • The presence of uncoordinated N atoms in ZnL can provide action sites for VB 6. • ZnL can be applied to specific detection of VB 6. • ZnL can exhibit high sensitivity and selectivity for the detection of VB 6. [ABSTRACT FROM AUTHOR]

A novel metal-organic framework film MIL-124 film was prepared on porous α-Al 2 O 3 ceramic plate by in situ synthesizing. After introducing Eu 3+ ions to the free -COOH sites of the MIL-124 ligand channels, a luminescent MOF film MIL-124@Eu 3+ was obtained. Based on the chemical reaction between NH 3 and the -COOH, the formation of -COONH 4 which was demonstrated by FT-IR spectrum, affected the energy transfer between Eu 3+ ions and ligand, quenching the characteristic emission of MIL-124@Eu 3+ film. The limit of detection to ammonia was calculated as 26.2 ppm in ambient air. The XRD results demonstrated the long-term stability of this ammonia sensor. The excellent performance and economical synthesizing strategy of the MIL-124@Eu 3+ film exhibited potential application of this sensor for detecting ammonia gas. [ABSTRACT FROM AUTHOR]

We present a real-time solution to the phase diversity problem when the observed objects are extended scenes. It utilizes an iterative linearization of the optical transfer functions (OTF) in at least two diversity planes by a first-order Taylor expansion to reconstruct initial wavefront. Vast simulation experiments are processed to verify the presented algorithm, including comparing our algorithm with the analytic estimator method, demonstrating that our method has high wavefront detection accuracy and large linearity range. [ABSTRACT FROM AUTHOR]

Glutathione (GSH) and cysteine (Cys) have similar structures but play different roles in biological systems, so it is important to realize simultaneously and effectively detect them in biomedical field such as disease diagnose, etc. Herein, a water-stability and spindle shape zinc metal-organic framework (Zn-DTBA) with the ligand (2′-dithiodibenzoic acid, H 2 DTBA) has been successfully obtained for simultaneously detecting GSH and Cys. Cys can react with the disulfide bond in H 2 DTBA, thereby destroying the crystal structure of Zn-DTBA and quenching the fluorescence. GSH can act on the junction between the ligand and the metal node during the detection process, causing the collapse of Zn-DTBA structure and releasing Zn2+ ion and ligand. Therefore, Zn-DTBA has different fluorescence response for GSH and Cys, and the limit of detection (LOD) for the sensing of GSH and Cys was estimated to be 0.28 and 0.76 μM respectively. In further, Zn-DTBA can be successfully applied to detect Cys and GSH in serum as well, which is conducive to expand the application range of Zn-DTBA in practical detection. This investigation indicates that Zn-DTBA can be used as a potential fluorescent probe for the future biological studies of biothiols sensing. • Zn-DTBA exhibits high water stability and pH stability. • The LOD of Zn-DTBA for the sensing of GSH and Cys is estimated to be 0.28 and 0.76μM respectively. • Zn-DTBA can be successfully applied to simultaneously detect Cys and GSH in serum. [ABSTRACT FROM AUTHOR]

Purpose and objectives To investigate the pattern of lymph node metastasis and treatment outcome after intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma (NPC), and assess the possibility of replacing Ho’s supraclavicular fossa (SCF) with the lower level (LL; cervical extension below caudal edge of cricoid cartilage) based on magnetic resonance imaging (MRI) as a criterion for N3 disease. Methods and materials We retrospectively reviewed 749 patients with biopsy-proven non-metastatic NPC treated with IMRT. Lymph node metastasis was mapped using the 2013 International Consensus Guidelines. Results Cervical lymph node (CLN) laterality, CLN greatest dimension (>60 vs. ⩽60 mm) and Ho’s SCF were independent prognostic factors for disease-free survival (DFS) and distant metastasis-free survival (DMFS; P < 0.01) in multivariate analysis. Replacing Ho’s SCF with the LL was also predictive for DFS and DMFS ( P < 0.01). Compared to the 7th UICC/AJCC, N-categories based on the LL provided more satisfactory distinction between hazard ratios for distant and disease failure for each N-category. N3a and N3b as defined by the 7th UICC/AJCC had similar DMFS ( P = 0.31) and DFS ( P = 0.21). Conclusions Replacing Ho’s SCF with the LL is simple and practical. The N-category staging system could be further simplified by merging N3 subcategories. [ABSTRACT FROM AUTHOR]

Lanthanide ions-doped fluoride nanocrystals have excellent application prospect. However, low photoluminescence quantum yield (PLQY) is usually along with lanthanide ions-doped fluoride nanocrystals owing to their low molar absorptivity and narrow absorption band. In order to increase the absorption cross section of Ln3+ in fluoride nanocrystals, a facile synthesis strategy to enhance luminescence of AF 2 : Ln3+ (A = Ca, Sr; Ln = Eu, Tb) by the use of carbon dots (CDs) has been developed in this work. A series of characterizations including TEM, XRD, FTIR and XPS demonstrated that the CDs have been successfully combined with the surface of AF 2 : Ln3+ nanocrystals. The combination of CDs has little influence on the microstructure and phase structure of AF 2 : Ln3+, and CDs@AF 2 : Ln3+ nanocrystals have uniform and regular shape with cubic phase. CDs are used as a broadband sensitizer and lead to the broadband excitation of Ln3+, resulting in the enhancement around 10-fold of Ln3+ luminescence emission in AF 2 : Ln3+ nanocrystals after CDs combination. The corresponding PLQY increases almost three times, and the luminescence enhancement mechanism by combining CDs is proposed. In addition, the CDs@AF 2 : Ln3+ nanocrystals are used to prepare CDs@AF 2 : Ln3+/PVA films, which exhibits excellent luminescence properties under the excitation of UV light. This work provides a superior method for enhancing the luminescence properties of lanthanide ions-doped nanocomposites and demonstrates practical potential as promising candidates for light-converting thin films. [Display omitted] • CDs can be as a broadband sensitizer to increase the absorption cross section of Ln3+ in AF 2 : Ln3+ nanocrystals. • The fluorescence emission of AF 2 : Ln3+ (A = Ca, Sr; Ln = Eu, Tb) increases by about 10 times by combining CDs. • CDs are able to capture the electrons of Ln3+ and transfer energy to Ln3+ in AF 2 : Ln3+ nanocrystals. • CDs@AF 2 : Eu3+/PVA film can be fabricated and converts UV to red light. [ABSTRACT FROM AUTHOR]

Salinity is a major factor limiting plant growth and agricultural production worldwide. Glycine betaine (GB) is one of the most universal osmoprotectants that protects plants from environmental stresses. In this study, transgenic cotton co-expressing ApGSMT2g and ApDMT2g was generated by Agrobacterium -mediated transformation. Compared with wild-type (WT), co-expression of ApGSMT2g and ApDMT2g in cotton results in higher GB amounts, higher relative water content (RWC), lower osmotic potential, more K + , and less Na + under salt stress, which contributes to maintaining intracellular osmoregulation and K + /Na + homeostasis and thus confers higher salt tolerance and more vigorous growth. Furthermore, co-expressing ApGSMT2g and ApDMT2g in cotton leads to better performance of PSII, greater photosynthesis capacity, and finally, improves plant growth and increases cotton seed yield compared to WT under salt stress. The reason for the better performance of PSII in transgenic cotton is the higher quantum yield and a more reasonable quantum ratio distribution than WT under salt stress. Co-expressing ApGSMT2g and ApDMT2g in cotton also reduces membrane damage and increases superoxide dismutase (SOD) activity compared to WT under salt stress. Our results indicate that transgenic ApGSMT2g and ApDMT2g cotton shows higher salt tolerance and more seed cotton yield in saline fields compared to wild-type. [ABSTRACT FROM AUTHOR]

The work attempts to investigate the effect of sepiolite nano-fibers addition on mechanical properties of bone china bodies. Compared with the traditional toughening fibers, the sepiolite nano-fiber has two main advantages: One is that the chemical composition of sepiolite mineral and the chemical composition of bone china raw materials are similar. So it can be used as one of the main components of bone china formulations directly. The other is that the sepiolite is a kind of cheap mineral resources, which will decrease the cost of the toughening ceramics. The flexural strength and fracture toughness were tested by three point bending method and single edge notched beam method, and the microstructure of the bone china was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM). The results showed that 2 wt% sepiolite fiber addition could increase the bending strength of the ceramic bodies. There were two toughening mechanisms in the reinforced ceramic. One was the fiber pull-out. The other was the weak interface mechanism. Plenty of micro-cracks came into being at the weak interface to consume most of the elastic strain energy to prevent main crack from spreading. [ABSTRACT FROM AUTHOR]

Abstract: Blue-green emitting ZnWO4 spherical nanoparticles, diameter about 50–60nm, are fabricated by hydrothermal synthesis. Field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), ultraviolet and visible (UV–vis) absorption and photoluminescence (PL) spectra were used to investigate the morphology, structure and luminescent properties. ZnWO4 nanoparticles doped with Eu3+ and Tb3+ ions exhibit red and green emission respectively under the excitation of UV light, and the PL integral intensity reaches the maximum with the amount of Eu3+ and Tb3+ dopant concentration up to 5.0mol%. It indicates that the full-color emission ranging from blue-green (non-doped) to green (Tb3+-doped) to red (Eu3+-doped) could be realized based on just one host material of ZnWO4. [Copyright &y& Elsevier]

Photochromic fluorescent switches have been attracting great research interest owing to their optical color and fluorescence can be reversibly modulated by light stimulation. An efficient way to construct photochromic fluorescence switching system is to integrate photochromic molecule with an energy level-matching fluorophore by non-covalent assembly. In this paper, we reported the design of a water-soluble photochromic fluorescent switch (OF–CO 2 H@Ce6Tb4·P) with dual signal changes (optical color change and fluorescence ON/OFF) by combining Ce, Tb co-doped phosphate hybrid (Ce6Tb4·P) and diarylethene containing carboxyl groups (OF–CO 2 H) via hydrogen bonding. Ce6Tb4·P showed the typical green fluorescence of terbium ions due to the sensitization effect of cerium ions. OF-CO 2 H can undergo reversible photoisomerization reaction, accompanied by changes in optical color (colorless to pink) and UV–visible absorption. Moreover, controlling the photoisomerization of OF-CO 2 H can regulates the spectral overlap between its absorption and Ce6Tb4·P emission, thus achieving reversible modulation of the optical color and fluorescence of OF-CO 2 H@Ce6Tb4·P. The demonstrations of photocontrolled dual-mode signaling in photoswitchable patterning shows that OF-CO 2 H@Ce6Tb4·P is suited for surface-involved photocontrolled applications such as advanced optical anti-counterfeiting and information storage. • A dual-mode photochromic fluorescent switch was constructed. • The mechanism of color and fluorescence changes of the switch was studied. • The switch was successfully applied in the field of intelligent anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Dendritic-like BiVO 4 :Ag heterostructure was formed in the process of visible light-irradiated photocatalysis using dendritic-like BiVO 4 as photocatalyst, AgNO 3 as additive and photocatalytic degradation of Rhodamine B (RhB) solution as model reaction. In the coexistence of BiVO 4 and AgNO 3 , Ag islands (nanoparticles) could be formed on the surface of dendritic-like BiVO 4 crystals after Ag + ions captured the photo-generated electrons, and hence the BiVO 4 :Ag heterostructure was obtained. The formation of Ag islands can be directly confirmed by TEM technique. The synergistic effect of the formation of BiVO 4 :Ag heterostructure and Ag + ions as electron capture agent leads to prominent improvement of the photocatalytic activity, i.e., the decolor efficiency of the dendritic-like BiVO 4 photocatalysts for degradation of RhB solution was prominently improved from 34.4% to 91.4% under visible light irradiation only for 20 min. [ABSTRACT FROM AUTHOR]

Abstract: Monodispersed SiO2@YPO4:Tb3+ core–shell submicrospheres were prepared through a simply homogeneous sol–gel method. The resulted SiO2@YPO4:Tb3+ core–shell particles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence spectra (PL) and kinetic decays. The XRD results demonstrate that the YPO4:Tb3+ layers begin to crystallize on the SiO2 spheres after annealing at 500°C and the crystallinity increases with raising the annealing temperature. The FTIR spectra show that the YPO4:Tb3+ shell has linked to the silica surface through forming a Si–O–Y bond. SEM and TEM analysis indicate that SiO2@YPO4:Tb3+ core–shell submicrospheres have the regular microstructures and uniform size distributions. The emission spectra of the obtained submicrospheres are dominated by 5D4–7F5 transition of Tb3+ (545nm, green), and the emission intensities of Tb3+ increase with increasing the annealing temperatures and the number of coating cycles. The optimum concentration for Tb3+ was determined to be 5mol % of Y3+ in YPO4 host. [Copyright &y& Elsevier]

Abstract: The aims of this investigation were to develop a procedure to prepare chelerythrine (CHE) loaded O-carboxymethylchitosan (O-CMCS) microspheres by emulsion cross-linking method and optimize the process and formulation variables using response surface methodology (RSM) with a three-level, three-factor Box–Behnken design (BBD). The independent variables studied were O-CMCS/CHE ratio, O/W phase ratio, and O-CMCS concentration, dependent variables (responses) were drug loading content and encapsulation efficiency. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The process and formulation variables were optimized to achieve maximum drug loading content and entrapment efficiency by the desirability function. The optimized microsphere formulation was characterized for particle size, shape, morphology and in vitro drug release. Results for mean particle size, drug loading content, entrapment efficiency, and in vitro drug release of CHE-loaded O-CMCS microspheres were found to be of 12.18μm, 4.16±3.36%, 57.40±2.30%, and 54.5% at pH 7.4 after 70h, respectively. The combination use of RSM, BBD and desirability function could provide a promising application for O-CMCS as controlled drug delivery carrier and help to develop procedures for a lab-scale microemulsion process. [Copyright &y& Elsevier]

CHP2 (calcineurin B homologous protein 2) was initially identified as a tumor-associated antigen highly expressed in hepatocellular carcinoma. Its biological function remains largely unknown except for a potential role in transmembrane Na+/H+ exchange. In the present study, we observed that ectopic expression of CHP2 promoted the proliferation of HEK293 cells, whereas knockdown of endogenous CHP2 expression in HepG2 inhibited cell proliferation. When inoculated into nude mice, CHP2 transfected HEK293 cells displayed markedly increased oncogenic potential. In analysis of the underlying molecular mechanisms, we found that like calcineurin B, CHP2 was able to bind to and stimulate the phosphatase activity of calcineurin A. In accord with this, CHP2-transfected cells showed increased nuclear presence of NFATc3 (nuclear factor of activated T cells) and enhanced NFAT activity. Finally, both accelerated cell proliferation and NFAT activation following CHP2 transfection could be suppressed by the calcineurin inhibitor cyclosporine A, suggesting an intrinsic connection between these events. Taken together, our results highlighted a potential role of CHP2 in tumorigenesis and revealed a novel function of CHP2 as an activator of the calcineurin/NFAT signaling pathway. [ABSTRACT FROM AUTHOR]

Abstract: The low-temperature heat capacity of xylitol was precisely measured in the temperature range from 80 to 390K by means of a small sample automated adiabatic calorimeter. A solid–liquid phase transition was found from the experimental C p –T curve in the temperature range 360–375K with the peak heat capacity at 369.04K. The dependence of heat capacity on the temperature was fitted to the following polynomial equations with least square method. In the temperature range of 80–360K, . In the temperature range of 370–390K, . The molar enthalpy and entropy of this transition were determined to be 33.26±0.17kJmol−1 and 90.12±0.45JK−1 mol−1, respectively. The standard thermodynamic functions and , were derived from the heat capacity data in the temperature range of 80 to 390K with an interval of 5K. The standard molar enthalpy of combustion and the standard molar enthalpy of formation of the compound have been determined, (C5H12O5, cr)=(−2463.2±1.2)kJmol−1and (C5H12O5, cr)=(−1219.3±0.3)kJmol−1, by means of a precision oxygen bomb combustion calorimeter at T =298.15K. DSC and TG measurements were performed to study the thermal stability of the compound. The results were in agreement with those obtained from heat capacity measurements. [Copyright &y& Elsevier]