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A ratiometric fluorescent probe with blue-emission fluorescence based on N, Si-doped carbon dots (N, Si-CDs) for the detection of balofloxacin (BLFX) was synthesized by simple one-pot hydrothermal carbonization using methotrexate and 3-aminopropyltriethoxysilane (APTES) as carbon materials. The obtained N, Si-CDs showed dual-emission band fluorescence characterization at 374 nm and 466 nm. Furthermore, the synthesized N, Si-CD probe exhibited evidence of ratiometric fluorescence emission characteristics (

Biotransformation of betulonic acid (1) by Rhizopus arrhizus CGMCC 3.868 resulted in the production of 16 new (3, 5, 6, and 9-21) and five known compounds. Structures of the new compounds were established by analysis of spectroscopic data. Hydroxylation, acetylation, oxygenation, glycosylation, and addition reactions involved the C-20-C-29 double bond. Antineuroinflammatory activities of the obtained compounds in NO production were tested in lipopolysaccharides-induced BV-2 cells. Compared with the substrate betulonic acid, biotransformation products 3, 8, 9, 14, and 21 exhibited an improved inhibitory effect, with IC50 values of 10.26, 11.09, 5.38, 1.55, and 4.69 μM, lower than that of the positive control, NG-monomethyl-l-arginine.

Sodium-selenium (Na-Se) batteries are promising alternatives to lithium-ion batteries for energy storage systems owing to their high energy density and natural abundance of Na resources. However, their drawbacks of low Se loading, dissolution of intermediate sodium polyselenides in the electrolyte and volumetric expansion of Se impede their real applications. To address these issues, herein, we report a multifunctional Se host with MoSe2 nanosheets coupled with nitrogen-doped porous carbon hollow spheres for the first time. The N-doped hollow carbon sphere structure could provide a large space for Se loading (Se content up to 72 wt%) and accommodate the volume expansion of Se species upon cycling. MoSe2 was chosen as a polar coupling component for the carbon matrix, owing to its low conversion reaction voltage. Based on density functional theory (DFT) calculations, the MoSe2 nanosheets coupled with hollow spheres could enhance the adsorption energy of the host to polyselenides chemically, which benefits the immobilization of polyselenides. Therefore, as a cathode for Na-Se batteries, the as-prepared composite exhibits excellent energy storage performance with long cycling life and superior rate performance. Our study of introducing transition metal selenides into Na-Se batteries may stimulate the designing of diverse Se-based cathodes.

In consideration of the severe hazards of radioactive uranium pollution, the rapid assessment of uranium in field and in vivo are urgently needed. In this work a novel biocompatible and sensitive visual fluorescent sensor based on aggregation-induced emission (AIE) was designed for onsite detection of UO

The graphene-like wrapped Ni@C catalysts were facilely synthesized by a modified sol–gel method. Nickel nitrate and citric acid (CA) were adopted as the raw materials to form sol–gel mixture. Under the circumstances, the additive CA were employed not only as a complexing agent but also as a carbon source. It is found that the calcination temperature and the mole ratios between Ni and CA are the key factors affecting the physical property and the catalytic performance of catalysts in the conversion of nitroarenes into corresponding anilines. The results show that the Ni@C-500(1:1) catalyst exhibited the best performance in the hydrogenation of o-chloronitrobenzenes (o-CNB) to o-chloroanilines (o-CAN). The yield of o-CAN was achieved at 100% when o-CNB was completely converted at 40.0 °C under 2.0 MPa H2 for 2.0 h. Furthermore, the Ni@C-500(1:1) catalyst could be separated and recovered easily after reaction by an external magnetic field. The investigated results indicate that the Ni@C-500(1:1) catalyst remained higher activity after using twelve times. More importantly, this kind of catalyst is also active for the selective hydrogenation of other nitroarenes into the corresponding anilines. This new synthetic method may pave a way for producing low-cost Ni@C catalysts on a large scale, which is attractive for industrial anilines applications.

The novel dual-emission carbon dots (DECDs) for highly selective and sensitive recognition of chlortetracycline (CTC) and cell imaging were synthesized successfully by one-step synthesis. The obtained DECDs possessed two fluorescence peaks (345 nm and 450 nm) and showed specific response to CTC, resulting in a decrease in fluorescence intensity at 345 nm, a blue shift, and an increase in fluorescence intensity at 450 nm. The obtained DECDs exhibited highly selective response to CTC and not to its analogues, such as tetracycline, doxycycline, and oxytetracycline. Thus, an excellent ratiometric probe for the detection of CTC was fabricated successfully and used for the detection of CTC in real samples with the detection limit (LOD) of 16.45 nM. More importantly, the DECDs were used for quantitative detection of CTC in living cells, which demonstrated excellent biocompatibility and broad prospects in biomedicine application. Finally, the excellent selectivity of DECDs toward CTC was attributed to the FRET mechanism and the formation of complexes.

Biotransformation of betulonic acid (

Three new lanthanide-nitronyl nitroxide radical complexes [Ln(tfac)3(NIT-2thz)] (Ln(III) = Gd 1, Tb 2, Dy 3; tfac = trifluoroacetylacetonate; NIT-2thz = 2-(2′-thiazolyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been synthesized. Single crystal X-ray diffraction analyses reveal that complexes 1–3 are isomorphous. They all crystallized in the C2/c space groups. Each central Ln(III) ion is eight-coordinated by three bischelate tfac ligands and one radical ligand. More specifically, NIT-2thz acts as a chelate ligand to link one Ln(III) ion through its nitrogen atom of the thiazole ring and oxygen atom of the N–O group to form a two-spin system. Magnetic studies show that Gd complex exhibits ferromagnetic Gd(III)–radical coupling, Tb and Dy complexes exhibit frequency-dependent out-of-phase signals.

Three lanthanide–nitronyl nitroxide radical complexes [Ln(hfac)3(NIT-2Br-4Py)]2 (Ln(III) = Gd (1), Tb (2), Dy (3); hfac = hexafluoroacetylacetonate; NIT-2Br-4Py = 2-(2′-bromo-4′-pyridyl)-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)) have been synthesized. Single crystal X-ray diffraction analysis reveals that complexes 1–3 are isomorphous in which NIT-2Br-4Py acts as a bridging ligand linking two Ln(III) ions through the nitrogen atom of pyridine ring and the oxygen atom of N O group to form a four-spin system. The magnetic studies show that ferromagnetic coupling interaction between Ln(III) ions and nitronyl nitroxide radical. Moreover, ac measurements show that Tb(III) complex exhibits frequency-dependent signals at low temperature.

Background Evidence-based practice (EBP) education or training are considered fundamental to building and strengthening an EBP culture, as well as to encouraging evidence-based academic and clinical practice in the nursing community. However, few valid and reliable instruments are available for the assessment of EBP teaching and learning in clinical nurses in China. Translation, reliability, and validity testing of the English Evidence-Based Practice Profile Questionnaire (EBP2Q), which has strong psychometric properties, may encourage evaluation and promote the implementation of EBP in Mainland China. Methods Based on established guidelines for the development of questionnaires, the English EBP2Q was translated and cross-culturally adapted. The Chinese version of the EBP2Q (EBP2Q-C) was validated using a sample of 543 nurses. Structural validity was evaluated through exploratory factor analysis and confirmatory factor analysis, and the questionnaire was tested for convergent and criterion validity. The internal consistency and test-retest reliability were also evaluated. Results The content validity index demonstrated good content validity (≥0.98). An eight-factor structure was obtained in the exploratory factor analysis, and verified by a three-order factor model from the confirmatory factor analysis (χ2/df = 2.001; RMSEA = 0.065; SRMR = 0.077; and CFI = 0.884). The Spearman’s rank correlation analysis of the EBP2Q-C with the Evidence-Based Practice Questionnaire showed moderate correlations for Practice (0.58) and Confidence (0.68) and a low correlation for Sympathy (0.32). Criterion validity was demonstrated by significant differences in terms of nurses’ highest education, present position, EBP training, involvement in research programs, and level of understanding of English. Both the overall Cronbach’s α and the Cronbach’s α for the domains exceeded 0.70. The intraclass correlation coefficients for the domains ranged between 0.75 and 0.96, indicating satisfactory repeatability. Conclusions Except for the convergent validity of the Sympathy domain, the EBP2Q-C provided evidence of validity and reliability. Therefore, it can be applied in EBP education or training assessment in Mainland China.

An unreported nitronyl nitroxide radical ligand and its corresponding radical-4f (complexes 1–3) and radical-3d-4f complexes (complexes 4–6) were successfully prepared. Structural analyses indicate that the complexes 1–3 are cyclic structures consist of two identical units of Ln(hfac)3(NIT-5-OCH3-3pyridine) (hfac = hexafluoroacetylacetone; Ln = Gd 1, Tb 2, Dy 3), while the complexes 4–6 show 1D zigzag structures with periodic [Rad–Ln–Rad–Cu] (Ln = Gd 4, Tb 5, Dy 6) units. Dc susceptibility measurements reveal that two different magnetic interactions coexist in complex 1: (i) ferromagnetic coupling between Gd3+ and radical through the N O group, (ii) weak antiferromagnetic interaction between Gd3+ and radical through the pyridine ring. While for complex 4, weak ferromagnetic coupling between Cu2+/Ln3+ and radical ligands as well as antiferromagnetic coupling between two adjacent radicals via the Ln3+ are observed at the same time. Furthermore, AC magnetic studies reveal that complexes 2, 3 and 5 display slow magnetization relaxation at low-temperature.

One hydroxyl-containing nitronyl nitroxide radical and its three mononuclear tri-spin compounds Ln(hfac)3(NIT-Ph-3-Br-4-OH)2 (Ln = Gd 1,Tb 2, Dy 3, and hfac = hexafluoroacetylacetonate NIT-Ph-3-Br-4-OH = 2-(3′-Br-4′-hydroxyl)-4,4,5,5- tetramethyl-imidazoline-1-oxyl-3-oxide) have been successfully prepared and characterized. Single crystal X-ray analyses show that complexes 1, 2 and 3 are isomorphous, and the center LnIII ions are eight-coordinated. Careful inspection of the structures reveal that short contact between ORadical atoms with phenolic hydroxy was observed, and hydrogen bonding has a significant function in determining the structure. The magnetic studies reveal that the ferromagnetic interactions between Ln–Radical and antiferromagnetic interactions between the intramolecular radicals coexist in these systems. Alternating current (ac) susceptibilities of Tb and Dy complex indicate that there are no obvious frequency dependent out-of-phase signals.

Carbon-supported PtPdRuIr, Pd@PtRuIr, PtPd@PtRuIr, and PtPdRu@PtRuIr catalysts were prepared by a colloidal method and their catalytic activities to the methanol oxidation reaction in the acidic media were extensively investigated at room temperature. The catalysts were characterized by transmission electron microscopy and X-ray diffraction techniques, and their electrochemical behavior was evaluated by the cyclic voltammetry. The PtPdRu@PtRuIr/C catalyst is found to yield much higher electrocatalytic activity than the other ones and the commercial catalyst. For example, the Pt metal mass-specific activity of this PtPdRu@PtRuIr/C (Pt content 10 wt%, 1.7 mA·cm−2·mg−1) electrocatalyst is ~3-fold higher than that of the commercial JM 40 % Pt/C (0.6 mA·cm−2·mg−1) electrocatalysts, and the If/Ib ratio of PtPdRu@PtRuIr/C is 1.6, which is higher than that of the JM 40 % Pt/C (0.9). The improvement may result from the high dispersion of the active metal catalyst and the synergistic effect between the PtRuIr and PtPdRu layers. It is thus concluded that the pseudo-core–shell structure could significantly improve the methanol electro-oxidation activity and CO tolerance of the electrocatalyst.

A high-performance, low platinum loading catalyst for the anodic oxidation of methanol, Pd@PtRu/C, is prepared by a two-step colloidal approach. The activity of the Pd@PtRu/C catalyst is 1.67 times and 1.81 times that of PtRu/C and PtRuPd/C catalysts, respectively. The catalysts are characterized by TEM, XPS, and XRD. The active components are dispersed on the surface of the carbon support very well, yielding a particle size of ca. 4.7 nm and a shell thickness of ca. 0.25 nm. The catalyst's high activity may be attributed to the high exposure and dispersion of PtRu, as well as the interaction of PtRu in the shell layer with Pd in the core, resulting from the catalyst's core–shell structure.

Small nanoparticles offer high surface areas and are certainly desirable for electrocatalytic reactions and fuel cells. However, the drawback of using small nanoparticles is their tendency towards particle aggregation. This paper aims to inhibit platinum agglomeration by adding silicon oxide to a carbon support for enhanced catalytic activity in low-temperature fuel cells. The catalysts are characterized by X-ray diffraction and transmission electron microscopy. Physical characterization and cyclic voltammetry techniques at room temperature are used to assess the effects of silicon oxide amount, post-heating temperature, and holding time on particle size and dispersion of active components, and the catalysts’ activity towards the methanol oxidation and oxygen reduction reactions. It is found that using a support of carbon powder with 3 wt.% silicon oxide can enhance the electrochemically active surface area of Pt catalysts and their activity towards the anodic oxidation of methanol and reduction of oxygen. The active components are also more resistant than Pt/C to agglomeration upon heating.

Carbon nanotubes (CNTs) were shortened from 5 to 15 μm to ca. 200 nm using ball milling with ethanol as the milling aid agent, and a platinum catalyst with these shortened carbon nanotubes (SCNTs) as the support was prepared by a high-pressure colloidal method. It was found that this catalyst with SCNTs showed much higher activity than a platinum catalyst with normal CNTs as support; for methanol anodic oxidation, the activity of the Pt/SCNTs was 50% higher than that of the Pt/CNTs, and the Pt/SCNTs also showed higher activity for the cathodic reduction of oxygen. The Pt/SCNTs were characterised by X-ray diffraction scanning and transmission electron microscropy. It is suggested that the significant performance enhancement when SCNTs are used as support might result from the generation of new surfaces and defects, the opening of closed nanotubes in the process of milling, higher platinum dispersion on the shortened nanotubes and the interaction of platinum nanoparticles with the SCNTs.

A palladium decorated Pt/C catalyst, Pt@Pd/C, is prepared by a colloidal approach with a small amount of platinum as core. It is found that the catalyst shows excellent activity towards anodic oxidation of formic acid at room temperature and its activity is 60% higher than that of Pd/C. Decoration of palladium shell on the platinum core is supported by XPS results. Due to the use of platinum as core, active components are dispersed very well and the particle sizes are smaller than those of Pd/C. The cyclic voltammetry measurement clearly shows synthetic electro-oxidation effects of formic acid on Pt@Pd/C. It is speculated that the high performance of Pt@Pd/C may result from the unique core–shell structure and synergistic effect of Pt and Pd at the interface. The preparation method for Pt@Pd/C reported in this work will provide additional options for the design of catalysts for direct formic acid fuel cell (DFAFC).

In this work, a membrane electrode assembly (MEA) for proton exchange membrane fuel cell (PEMFC) operating under no external humidification has been successfully fabricated by using a composite Pt/SiO2/C catalyst at the anode. In the composite catalyst, amorphous silica, which originated from the hydrolysis of tetraethyl orthosilicate (TEOS), was immobilized on the surface of carbon powder to enhance the stability of silica and provide a well-humidified surrounding for proton transport in the catalyst layer. The characteristics of silica in the composite catalyst were investigated by XRD, SEM and XPS analysis. The single cell tests showed that the performance of the novel MEA was comparable to MEAs prepared using a standard commercial Pt/C catalyst with 100% external humidification, when both were operated on hydrogen and air. However, in the absence of humidification, the MEA using Pt/SiO2/C catalyst at the anode continued to show excellent performance, while the performance of the MEA containing only the Pt/C catalyst rapidly decayed. Long-term testing for 80 h further confirmed the high performance of the non-humidified MEA prepared with the composite catalyst. Based on the experimental data, a possible self-humidifying mechanism was proposed.

Conventional double catalyst layer (DCL) structures show no obvious improvement in cathode performance, due to the contradiction between improving mass transfer and maintaining good platinum (Pt) utilization. To decrease this conflict, a novel DCL cathode is prepared using catalysts with two different amounts of Pt; the catalyst with higher Pt content is used in the inner layer to concentrate the Pt, and the catalyst containing less Pt is used in the outer layer to maintain a suitable layer thickness. Polarization characteristics of cathodes with this novel DCL, a conventional DCL, and a single catalyst layer (SCL) are evaluated at ambient pressure in an H 2 /air PEMFC. The results show a significant increase in performance with the novel DCL cathode. Compared with the SCL cathode, the current density of the novel DCL cathode at 0.6 V increases by 35.9%, while that of the conventional DCL cathode increases by just 8.8%.

Highly dispersed, high performance Pt and PtRu catalysts, supported on multiwalled carbon nanotubes (CNTs), were prepared by a high pressure organic colloid method. The particle sizes of the active components were as small as 1.2 nm for Pt and 1.1 nm for PtRu, and the active Pt surface areas were 295 and 395 m2/g, respectively. The catalysts showed very high activities toward the anodic oxidation of methanol, evaluated by cyclic voltammetry, being up to 4 times higher than that of commercial Johnson Matthey Hispec 2000 Pt/XC-72R and 5 times better than Hispec 5000 PtRu/XC-72R catalysts. In a full air/hydrogen fuel cell, a membrane-electrode assembly prepared using our Pt/CNT and PtRu/CNT catalysts showed 50% and 100% higher performances than those prepared with commercial Johnson Matthey Pt/XC-72R and PtRu/XC-72R catalysts for the same Pt loading and operating conditions.

A core–shell structured low-Pt catalyst, PdPt@Pt/C, with high performance towards both methanol anodic oxidation and oxygen cathodic reduction, as well as in a single hydrogen/air fuel cell, is prepared by a novel two-step colloidal approach. For the anodic oxidation of methanol, the catalyst shows three times higher activity than commercial Tanaka 50 wt% Pt/C catalyst; furthermore, the ratio of forward current I f to backward current I b is high up to 1.04, whereas for general platinum catalysts the ratio is only ca. 0.70, indicating that this PdPt@Pt/C catalyst has high activity towards methanol anodic oxidation and good tolerance to the intermediates of methanol oxidation. The catalyst is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The core–shell structure of the catalyst is revealed by XRD and TEM, and is also supported by underpotential deposition of hydrogen (UPDH). The high performance of the PdPt@Pt/C catalyst may make it a promising and competitive low-Pt catalyst for hydrogen fueled polymer electrolyte membrane fuel cell (PEMFC) or direct methanol fuel cell (DMFC) applications.

Underwater acoustic signal with nonlinear dynamic characteristic has a very important research value to the prediction and filtering. The prediction and filtering for underwater acoustic signal, especially the reverberation and background noise, is the foundation of underwater target signal detection, and has important application in the non-stationary, non-Gaussian and nonlinear underwater acoustic signal processing. According to the typical linear theory of least square estimation and the Volterra series theory, the models of target signal are established respectively to process the further one-step and multi-step prediction, after comparing and analyzing the predict results, the optimal prediction parameters are selected. The prediction results show that for predicting the underwater acoustic signal, the prediction relative error of Volterra filter model based on the singular value decomposition is an order of magnitude smaller than the method of least square estimation, and the prediction results more close to the real values.

Three types of ternary low-platinum nanocatalysts, alloy PdPtIr/C, core–shell PdPt@PtIr/C and Pd@PtIr/C, have been prepared, and their catalytic behaviors toward methanol oxidation reaction (MOR)/oxygen reduction reaction (ORR) are comparatively investigated via cyclic voltammetry and chronoamperometry analysis in an acidic medium. Through a two-step colloidal technique, the synthesized core–shell structured catalyst PtPd@PtIr/C with alloy core and alloy shell show the best catalytic activity toward MOR and the best poisoning tolerance. The alloy PdPtIr/C catalyst prepared via a one-step colloidal technique exhibits the best performance toward ORR among the three catalysts. All the three catalysts are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and other characterization techniques.

To assess the distribution of subgingival flora after restoration of dentition defect with conical telescopic removable denture in patients with periodontitis.36 spots of 18 patients were examined and recorded for periodontal depth (PD) and gingival index(GI). Samples from subgingival pocket were collected, cultured, evaluated and compared between abutment teeth group and nonabutment teeth group. Chi-square test was used to determine the difference in each of these positive detecting rates by SPSS 10.0 software.3 years after restoration, the GI and PD of abutment teeth were normal, while those of the non-abutment teeth were higher. The positive rate for anaerobe in subgingival pocket after restoration, were significantly higher than that before restoration in both groups (P0.05).Conical telescopic removable denture is efficient in controlling the accumulation and attachment of nosogenetic microorganisms, preventing periodontitis from recurring and is a preferred prosthesis for dentition defect with periodontitis.

A temperature sensor based on polarization non–reciprocity(PNR)in fiber-optic Sagnac interferometer(PSI)can measure the temperature of one point in high precision. The phasic subtraction of two light beams was shifted while temperature field around the probe changed. Analyzing the temperature measuring theory of Sagnac fiber optic temperature sensor, a linear output model Was established. The all digital signal detection was based onsquare–wave modulation and demodulation. An all digital signal detecting system using C8051 F060 as its COre Was completed. The experimental data achieved by temperature experiments agree with theory well. The input and output of system achieve a linearity of 10°C. Discussion shows that this kind of temperature sensor can reach high precision.