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Bijelic A, Aureliano M, Rompel A. Polyoxometalates as Potential Next-Generation Metallodrugs in the Combat Against Cancer. Angew Chem Int Ed Engl 2019; 58:2980-2999. [PMID: 29893459 PMCID: PMC6391951 DOI: 10.1002/anie.201803868] [Citation(s) in RCA: 305] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Indexed: 02/05/2023]
Abstract
Polyoxometalates (POMs) are an emerging class of inorganic metal oxides, which over the last decades demonstrated promising biological activities by the virtue of their great diversity in structures and properties. They possess high potential for the inhibition of various tumor types; however, their unspecific interactions with biomolecules and toxicity impede their clinical usage. The current focus of the field of biologically active POMs lies on organically functionalized and POM-based nanocomposite structures as these hybrids show enhanced anticancer activity and significantly reduced toxicity towards normal cells in comparison to unmodified POMs. Although the antitumor activity of POMs is well documented, their mechanisms of action are still not well understood. In this Review, an overview is given of the cytotoxic effects of POMs with a special focus on POM-based hybrid and nanocomposite structures. Furthermore, we aim to provide proposed mode of actions and to identify molecular targets. POMs are expected to develop into the next generation of anticancer drugs that selectively target cancer cells while sparing healthy cells.
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Wang S, Lv X, Su Y, Fan Z, Fang W, Duan J, Zhang S, Ma B, Liu F, Chen H, Geng Z, Liu H. Piezoelectric Microchip for Cell Lysis through Cell-Microparticle Collision within a Microdroplet Driven by Surface Acoustic Wave Oscillation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1804593. [PMID: 30690881 DOI: 10.1002/smll.201804593] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/20/2018] [Indexed: 05/25/2023]
Abstract
Cell lysis is an important and crucial step for the detection of intracellular secrets. Usually, cell lysis is based on strong ultrasonic waves or toxic chemical regents, which require a large amount of cell suspension. To obtain high efficiency cell lysis for a small amount of sample, a mechanical cell lysis method based on a surface acoustic wave (SAW) microchip is proposed. The microchip simply consists of a piece of LiNbO3 crystal substrate, interdigitated transducers (IDTs) with 80 pairs of parallel electrodes and 3M Magic Tapes. The modulated input electrical signal is coupled into the substrate through IDTs, which produces an acoustic stream in the droplet on the surface of a substrate. When a biofluid droplet containing cells and microparticles is dropped on the surface of the microchip, the cells and microparticles are accelerated and collide with each other. The fluorescence staining results illustrate that the cell membrane is efficiently destroyed and that proteins as well as nucleic acids inside the cell are released. The experimental results show that this method has a high efficiency and low sample consumption. The potential application is the pretreatment of a small amount of tested sample in a hospital or biolab.
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Pantaroto HN, Amorim KP, Matozinho Cordeiro J, Souza JGS, Ricomini-Filho AP, Rangel EC, Ribeiro ALR, Vaz LG, Barão VAR. Proteome analysis of the salivary pellicle formed on titanium alloys containing niobium and zirconium. BIOFOULING 2019; 35:173-186. [PMID: 30935231 DOI: 10.1080/08927014.2019.1580360] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/17/2019] [Accepted: 02/04/2019] [Indexed: 06/09/2023]
Abstract
The chemical composition of biomaterials can drive their biological responses; therefore, this in vitro study aimed to evaluate the proteomic profile of the salivary pellicle formed on titanium (Ti) alloys containing niobium (Nb) and zirconium (Zr). The experimental groups consisted of Ti35NbxZr (x = 5 and 10 wt%) alloys, and commercially pure titanium (cpTi); titanium aluminium vanadium (Ti6Al4V) alloys were used as controls. The physical and chemical characteristics of the Ti materials were analysed. The proteomic profile was evaluated by liquid chromatography coupled with tandem mass spectrometry. Bacterial adhesion (2 h) of mixed species (Streptococcus sanguinis and Actinomyces naeslundii) was investigated as colony-forming units (n = 6). This paper reports the finding that salivary pellicle composition can be modulated by the composition of the Ti material. The Ti35NbxZr group showed a significant ability to adsorb proteins from saliva, which can favour interactions with cells and compatibility with the body.
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Rega R, Gennari O, Mecozzi L, Pagliarulo V, Bramanti A, Ferraro P, Grilli S. Maskless Arrayed Nanofiber Mats by Bipolar Pyroelectrospinning. ACS APPLIED MATERIALS & INTERFACES 2019; 11:3382-3387. [PMID: 30609347 DOI: 10.1021/acsami.8b12513] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The numerous advantages of micro- and nanostructures produced by electrospinning (ES) have stimulated enormous interest in this technology with potential application in several fields. However, ES still has some limitations in controlling the geometrical arrangement of the fiber mats so that expensive and time-consuming technologies are usually employed for producing ordered geometries. Here we present a technique that we call "bipolar pyroelectrospinning" (b-PES) for generating ordered arrays of fiber mats in a direct manner by using the bipolar pyroelectric field produced by a periodically poled lithium niobate crystal (PPLN). The b-PES is free from expensive electrodes, nozzles, and masks because it makes use simply of the structured pyroelectric field produced by the PPLN crystal used as collector. The results show clearly the reliability of the technique in producing a wide variety of arrayed fiber mats that could find application in bioengineering or many other fields. Preliminary results of live cells patterning under controlled geometrical constraints is also reported and discussed in order to show potential exploitation as a scaffold in tissue engineering.
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Ureña J, Tabares E, Tsipas S, Jiménez-Morales A, Gordo E. Dry sliding wear behaviour of β-type Ti-Nb and Ti-Mo surfaces designed by diffusion treatments for biomedical applications. J Mech Behav Biomed Mater 2018; 91:335-344. [PMID: 30641479 DOI: 10.1016/j.jmbbm.2018.12.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 06/12/2018] [Accepted: 12/21/2018] [Indexed: 11/18/2022]
Abstract
The dry sliding wear behaviour of different Ti-Nb and Ti-Mo surfaces was investigated in order to evaluate the role of Nb and Mo β-stabilizing elements in titanium wear resistance to consider them for biomedical applications. Dry sliding wear tests were performed under unlubricated conditions using a ball-on-plate tribometer (UMT) with reciprocating lineal movement of 1 Hz frequency at different loads (2 and 5 N) and against two counterface materials (alumina and stainless steel) to assess the effect of these parameters on wear. The results indicated an improvement in wear resistance for all the modified Ti surfaces. Metal-on-metal surfaces exhibited higher wear rate than ceramic-on-metal, and higher wear was observed for the more severe conditions. Wear rate values on modified surfaces were between 53% and 96% lower compared to pure Ti tested at 2 N, and up to 79% lower than Ti at 5 N. In both cases the highest wear reduction was observed for Ti-MoNH4Cl surface.
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da Silva SW, Navarro EMO, Rodrigues MAS, Bernardes AM, Pérez-Herranz V. The role of the anode material and water matrix in the electrochemical oxidation of norfloxacin. CHEMOSPHERE 2018; 210:615-623. [PMID: 30031345 DOI: 10.1016/j.chemosphere.2018.07.057] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 06/08/2023]
Abstract
The roles of the anode material, boron-doped diamond (BDD), with different boron (B) and substrate Silicon (Si) or Niobium (Nb) content, and one dimensionally stable anode (DSA®), were evaluated in the oxidation of norfloxacin (NOR) by electrochemical advanced oxidation process (EAOP). The effect of other components in real wastewater on the performance of EAOP was also studied. The anode materials were characterized by cyclic voltammetry, regarding diamond quality, electro-generation of oxidants and NOR oxidation mechanism (direct and/or indirect). The results showed that the anode material influences on the NOR oxidation pathway, due to distinct characteristics of the substrate and the coating. Apparently, low difference in diamond-sp³/sp2-carbon ratio (Si/BDD100 × Si/BDD2500) does not leads to significant differences in the EAOP. On the other hand, the variation in the sp³/sp2 ratio seems to be higher when Si/BDD2500 and Nb/BDD2500 are compared, which would explain the best current efficiency result for Si substrate. However, the Nb substrate presented a similar current efficiency and a 60% lower energy consumption. Dissolved organic matter (DOM) present in the real wastewater affect the EAOP-Nb/BDD due to HO and persulfate ions scavenged. However, when supporting electrolyte was added to a real wastewater spiked with NOR, the NOR decay reaches similar values found to the synthetic one. Due to the energy saving and mechanical properties, Nb substrate presents some technological advantages in relation to Si, which can facilitate the application to industrial levels.
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Slenders E, Bové H, Urbain M, Mugnier Y, Sonay AY, Pantazis P, Bonacina L, Vanden Berghe P, vandeVen M, Ameloot M. Image Correlation Spectroscopy with Second Harmonic Generating Nanoparticles in Suspension and in Cells. J Phys Chem Lett 2018; 9:6112-6118. [PMID: 30273489 DOI: 10.1021/acs.jpclett.8b02686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The absence of photobleaching, blinking, and saturation combined with a high contrast provides unique advantages of higher-harmonic generating nanoparticles over fluorescent probes, allowing for prolonged correlation spectroscopy studies. We apply the coherent intensity fluctuation model to study the mobility of second harmonic generating nanoparticles. A concise protocol is presented for quantifying the diffusion coefficient from a single spectroscopy measurement without the need for separate point-spread-function calibrations. The technique's applicability is illustrated on nominally 56 nm LiNbO3 nanoparticles. We perform label-free raster image correlation spectroscopy imaging in aqueous suspension and spatiotemporal image correlation spectroscopy in A549 human lung carcinoma cells. In good agreement with the expected theoretical result, the measured diffusion coefficient in water at room temperature is (7.5 ± 0.3) μm2/s. The diffusion coefficient in the cells is more than 103 times lower and heterogeneous, with an average of (3.7 ± 1.5) × 10-3 μm2/s.
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Palas B, Ersöz G, Atalay S. Catalytic wet air oxidation of Reactive Black 5 in the presence of LaNiO 3 perovskite catalyst as a green process for azo dye removal. CHEMOSPHERE 2018; 209:823-830. [PMID: 30114730 DOI: 10.1016/j.chemosphere.2018.06.151] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/22/2018] [Accepted: 06/24/2018] [Indexed: 06/08/2023]
Abstract
The removal of textile azo dye, Reactive Black from the aqueous solutions by catalytic wet air oxidation in the presence of LaNiO3 perovskite catalyst has been investigated. The most suitable reaction conditions were determined by testing various the catalyst loadings, reaction temperature and pressure values, and the initial pH of the Reactive Black 5 solutions. The most suitable reaction conditions with 0.61 L/min of air flow rate were found to be 1 g/L of LaNiO3 loading, 50 °C of reaction temperature, 1 atm of reaction pressure, and, pH = 3 for the oxidation of 100 mg/L Reactive Black solutions. Under these conditions the degradation and the decolorization efficiencies were evaluated as 65.4% and 89.6%, respectively. The phytotoxicity analyzes were carried out by using Lepidium sativum. According to the toxicity tests a remarkable decrease in the growth inhibition was achieved by the catalytic wet air oxidation in the presence of LaNiO3 catalyst. The growth inhibition in the untreated and treated dye solutions were calculated as 49.3% and 23.7%, respectively.
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Ribeiro MCM, Amorim CC, Moreira RFPM, Oliveira LCA, Henriques AB, Leão MMD. Development of Fe/Nb-based solar photocatalysts for water treatment: impact of different synthesis routes on materials properties. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:27737-27747. [PMID: 29700754 DOI: 10.1007/s11356-018-2006-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 04/11/2018] [Indexed: 06/08/2023]
Abstract
Semiconductors based on Fe/Nb oxides can present both solar sensitivity and high catalytic activity. However, there is still a lack regarding the comparison between different routes to produce Fe/Nb-based solar photocatalysts and the evaluation of the impact of the synthesis operating conditions on the material properties. In this work, Fe/Nb2O5 ratio, type of precipitating agent, presence/absence of washing stage, and temperature of calcination were verified to be the most relevant parameters in the synthesis by the co-precipitation method. These factors led to remarkable differences in the properties and performance of the photocatalysts produced by each distinct synthesis route. Composition, iron species present in the materials, crystallinity characteristics, and pH of the catalysts were affected, leading to different photocatalytic activities under UV-Vis light. Due to their characteristics, the synthesized materials are potential photocatalysts for application in solar processes. Graphical abstract ᅟ.
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Thanka Rajan S, Bendavid A, Subramanian B. Cytocompatibility assessment of Ti-Nb-Zr-Si thin film metallic glasses with enhanced osteoblast differentiation for biomedical applications. Colloids Surf B Biointerfaces 2018; 173:109-120. [PMID: 30273871 DOI: 10.1016/j.colsurfb.2018.09.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/02/2018] [Accepted: 09/19/2018] [Indexed: 01/17/2023]
Abstract
Biologically safe Ti-based quaternary Ti-Nb-Zr-Si thin film metallic glass (TFMG) was fabricated by sputtering on Titanium alloy (Ti6Al4V or Ti alloy) substrates. A preliminary assessment regarding glass forming ability, thermal stability and corrosion behavior was performed. The amorphous nature of the film is evidenced from the X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) and Selected Area Electron Diffraction (SAED) patterns. Ion scattering spectroscopy (ISS) and X-ray Photoelectron Spectroscopy (XPS) were used to analyse the chemical composition of surface which indicated oxygen on the top surface of the film and confirms the presence of Ti, Nb, Si, Zr without any other impurities. The surface morphology of the film showed a smooth surface as observed from scanning electron microscope (SEM) and atomic force microscope (AFM) analysis. It is found that the TFMG can sustain in the body-fluid, exhibiting superior corrosion resistance and electrochemical stability than the bare titanium. The cytotoxicity studies with L929 fibroblast cells showed that coatings were graded as zero and non-cytotoxic in nature. No hemolysis was observed on the coated surface indicating a better hemocompatibility. Assay using SaOS-2 bone cells showed good growth on the coated surfaces. The calcium assay showed that the SaOS-2 cells grown and differentiated on the control (Tissue Culture Polystyrene) TCPS surface had the highest mineral level. Higher alkaline phosphatase activity is obtained in SaOS-2 osteoblast cell cultures on TFMG than the control.
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Mao J, Tao F, Zhang Z, Zhou R. Promoting effect of Nb doping on catalytic performance for deep oxidation of 1, 2-dichloroethane over (Ce,Cr) xO 2-Nb 2O 5 catalysts. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:27413-27422. [PMID: 30039487 DOI: 10.1007/s11356-018-2709-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
A series of Nb-doped (Ce,Cr)xO2-Nb2O5 mixed oxides with varying (Ce,Cr)xO2/Nb2O5 mass ratio were prepared by a co-precipitation method and evaluated for the catalytic performance of eliminating 1,2-dichloroethane (DCE). The results indicate that there exists a strong synergistic effect between acid sites and redox species in (Ce,Cr)xO2-Nb2O5 improving the catalytic activity for DCE oxidation. Appropriate Nb doping could promote the high dispersion and the interaction of metal oxides in the (Ce,Cr)xO2-Nb2O5 catalysts, resulting in the formation of more Cr6+ species with strong oxidizing ability and excellent mobility of oxygen species from bulk to surface to create more active sites for DCE deep oxidation. The (Ce,Cr)xO2-Nb2O5 catalysts with (Ce,Cr)xO2/Nb2O5 ratios of 2/1~1/2 exhibit excellent catalytic activity and durability for DCE degradation in dry air as well as benzene or water vapor, and less chlorinated byproduct is produced during the degradation of DCE.
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Souza L, Lopes JH, Encarnação D, Mazali IO, Martin RA, Camilli JA, Bertran CA. Comprehensive in vitro and in vivo studies of novel melt-derived Nb-substituted 45S5 bioglass reveal its enhanced bioactive properties for bone healing. Sci Rep 2018; 8:12808. [PMID: 30143690 PMCID: PMC6109119 DOI: 10.1038/s41598-018-31114-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/02/2018] [Indexed: 12/15/2022] Open
Abstract
The present work presents and discusses the results of a comprehensive study on the bioactive properties of Nb-substituted silicate glass derived from 45S5 bioglass. In vitro and in vivo experiments were performed. We undertook three different types of in vitro analyses: (i) investigation of the kinetics of chemical reactivity and the bioactivity of Nb-substituted glass in simulated body fluid (SBF) by 31P MASNMR spectroscopy, (ii) determination of ionic leaching profiles in buffered solution by inductively coupled plasma optical emission spectrometry (ICP-OES), and (iii) assessment of the compatibility and osteogenic differentiation of human embryonic stem cells (hESCs) treated with dissolution products of different compositions of Nb-substituted glass. The results revealed that Nb-substituted glass is not toxic to hESCs. Moreover, adding up to 1.3 mol% of Nb2O5 to 45S5 bioglass significantly enhanced its osteogenic capacity. For the in vivo experiments, trial glass rods were implanted into circular defects in rat tibia in order to evaluate their biocompatibility and bioactivity. Results showed all Nb-containing glass was biocompatible and that the addition of 1.3 mol% of Nb2O5, replacing phosphorous, increases the osteostimulation of bioglass. Therefore, these results support the assertion that Nb-substituted glass is suitable for biomedical applications.
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Guo T, Li X, Liu X, Guo Y, Wang Y. Catalytic Transformation of Lignocellulosic Biomass into Arenes, 5-Hydroxymethylfurfural, and Furfural. CHEMSUSCHEM 2018; 11:2758-2765. [PMID: 30009402 DOI: 10.1002/cssc.201800967] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/10/2018] [Indexed: 05/27/2023]
Abstract
The complete transformation of lignocellulosic biomass into valuable platform chemicals is of great significance. Herein, a catalytic process for the upgrading of lignocellulose to arenes, 5-hydroxymethylfurfural (HMF), and furfural is reported. Firstly, the lignin fraction in lignocellulosic biomass is selectively converted into lignin oil (82.9 mol % yield of lignin monomers from birch wood) over a Pd/C catalyst and then further hydrodeoxygenated to arenes in catalytic hydrogen-transfer reactions over a Ru/Nb2 O5 catalyst. High yields of C7 -C9 hydrocarbons (95.6 mol %) with 85.6 wt % selectivity to arenes based on lignin oil are achieved owing to the synergistic effect between Ru and Nb2 O5 , which enables direct hydrogenolysis of the Caromatic -OH bond in phenolics. Secondly, the cellulose and hemicellulose fractions in the Pd/C-containing solid residue, as well as methylated C5 sugars produced during the stripping of lignin, are converted into HMF and furfural with a total yield of up to 24.5 wt % (based on the amount of birch wood) in a THF/concentrated seawater (ca. 30 wt % salts) biphasic reaction system. Here, seawater played a key role in the conversion of cellulose and hemicellulose into HMF and furfural, respectively; more importantly, it made the separation and reuse of the Pd/C catalyst easier. With this catalytic process, the complete and efficient transformation of lignocellulose into highly value-added products with recycling of each catalyst and solvent has been realized.
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You H, Wu Z, Wang L, Jia Y, Li S, Zou J. Highly efficient pyrocatalysis of pyroelectric NaNbO 3 shape-controllable nanoparticles for room-temperature dye decomposition. CHEMOSPHERE 2018; 199:531-537. [PMID: 29455123 DOI: 10.1016/j.chemosphere.2018.02.059] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 05/19/2023]
Abstract
In this work, pyrocatalytic effect is realized in hydrothermally-synthesized pyroelectric NaNbO3 shape-controllable nanoparticles via the product of pyroelectric effect and electrochemical redox. A pyro-catalysis is designed to decompose dye wastewater. Under the 23-50 °C heating-cooling cycle, the maximum pyrocatalytic decomposition ratio of NaNbO3 nanorods, nanosheets and nanocubes are 96%, 76% and 33%, respectively. The pyrocatalytic effect of NaNbO3 nanoparticles is potential in developing a environmentally-friendly technology for room-temperature pyrocatalysis through utilizing natural heat energy.
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Damodaran V, Vasa NJ, Sarathi R. KTN-based high-speed axial and lateral scanning technique for an optical coherence tomography system and application to dental imaging. APPLIED OPTICS 2018; 57:2915-2922. [PMID: 29714295 DOI: 10.1364/ao.57.002915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
A high-speed 840 nm based polarization-sensitive time domain optical coherence tomography (PSOCT) technique is proposed and demonstrated based on the quadratic electro-optic property of potassium tantalate niobate (KTN) crystals. A longitudinal (axial) scanning depth of ≈10 μm is obtained for an applied AC voltage of 600 V, at 1000 Hz and temperature maintained around 40°C. The OCT system with the KTN-based electro-optic delay line combined with a linear actuation is extended to image an early dental demineralization. For enhanced contrast by the elimination of the strong surface reflection from the sample and high-speed imaging, the quadratic electro-optically tunable PSOCT technique is proposed and demonstrated. Further, a lateral scanning range of 490 μm is also demonstrated by controlling the KTN temperature at 35°C for an applied voltage of 600 V on the tooth sample. This KTN-based quadratic electro-optic delay line combined with lateral scan approach provides an automated high-speed two-dimensional scanning of samples of interest.
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Du Y, Zhang S, Wang J, Wu J, Dai H. Nb 2O 5 nanowires in-situ grown on carbon fiber: A high-efficiency material for the photocatalytic reduction of Cr(VI). J Environ Sci (China) 2018; 66:358-367. [PMID: 29628105 DOI: 10.1016/j.jes.2017.04.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/20/2017] [Indexed: 06/08/2023]
Abstract
Niobium oxide nanowire-deposited carbon fiber (CF) samples were prepared using a hydrothermal method with amorphous Nb2O5·nH2O as precursor. The physical properties of the samples were characterized by means of numerous techniques, including X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), UV-visible spectroscopy (UV-vis), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy. The efficiency for the removal of Cr(VI) was determined. Parameters such as pH value and initial Cr(VI) concentration could influence the Cr(VI) removal efficiency or adsorption capacity of the Nb2O5/carbon fiber sample obtained after hydrothermal treatment at 160°C for 14hr. The maximal Cr(VI) adsorption capacity of the Nb2O5 nanowire/CF sample was 115mg/g. This Nb2O5/CF sample also showed excellent photocatalytic activity and stability for the reduction of Cr(VI) under UV-light irradiation: the Cr(VI) removal efficiency reached 99.9% after UV-light irradiation for 1hr and there was no significant decrease in photocatalytic performance after the use of the sample for 10 repeated cycles. Such excellent Cr(VI) adsorption capacity and photocatalytic performance was related to its high surface area, abundant surface hydroxyl groups, and good UV-light absorption ability.
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Furusato S, Takagaki A, Hayashi S, Miyazato A, Kikuchi R, Oyama ST. Mechanochemical Decomposition of Crystalline Cellulose in the Presence of Protonated Layered Niobium Molybdate Solid Acid Catalyst. CHEMSUSCHEM 2018; 11:888-896. [PMID: 29380543 DOI: 10.1002/cssc.201702305] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/12/2018] [Indexed: 06/07/2023]
Abstract
Direct depolymerization of crystalline cellulose into water-soluble sugars by solvent-free ball milling was examined in the presence of a strongly acidic layered metal oxide, HNbMoO6 , resulting in full conversion with 72 % yield of water-soluble sugars. Measurements by 13 C cross-polarization magic angle spinning NMR spectroscopy and X-ray diffraction revealed that amorphization of cellulose occurred rapidly within 10 min. Scanning electron microscopy equipped with an energy dispersive X-ray indicated that the substrate and the catalyst were well mixed during milling. The time course of the product distribution showed that most of the resultant water-soluble sugars were produced not by successive degradation of oligosaccharides but by direct depolymerization of cellulose chains. The products included glucose, mannose, and cello-oligomers, as well as anhydrosugars. Addition of small amounts of polar solvents increased the sugar yield, whereas further addition of water decreased the selectivity to anhydrosugars. Calculations of the mechanical energy required for the ball-milling process showed that 0.02 % was utilized for the chemical transformation under the conditions examined in this study.
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Zhu L, Zhong Z, Xue J, Xu Y, Wang C, Wang L. NH 3-SCR performance and the resistance to SO 2 for Nb doped vanadium based catalyst at low temperatures. J Environ Sci (China) 2018; 65:306-316. [PMID: 29548402 DOI: 10.1016/j.jes.2017.06.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 05/26/2017] [Accepted: 06/27/2017] [Indexed: 06/08/2023]
Abstract
Niobium oxide as the promoter was doped in the V/WTi catalyst for the selective catalytic reduction (SCR) of NO. The results showed that the addition of Nb2O5 could improve the SCR activity at low temperatures and the 6wt.% additive was an appropriate dosage. The enhanced reaction activity of adsorbed ammonia species and the improved dispersion of vanadium oxide might be the reasons for the elevation of SCR activity at low temperatures. The resistances to SO2 of 3V6Nb/WTi catalyst at different temperatures were investigated. FTIR spectrum and TG-FTIR result indicated that the deposition of ammonium sulfate species was the main deactivation reason at low temperatures, which still exhibited the reactivity with NO above 200°C on the catalyst surface. There was a synergistic effect among NH3, H2O and SO2 that NH3 and H2O both accelerated the catalyst deactivation in the presence of SO2 at 175°C. The thermal treatment at 400°C could regenerate the deactivated catalyst and get SCR activity recovered. The particle and monolith catalysts both kept stable NOx conversion at 225°C with high concentration of H2O and SO2 during the long time tests.
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Su T, Peng R, Hood ZD, Naguib M, Ivanov IN, Keum JK, Qin Z, Guo Z, Wu Z. One-Step Synthesis of Nb 2 O 5 /C/Nb 2 C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution. CHEMSUSCHEM 2018; 11:688-699. [PMID: 29281767 DOI: 10.1002/cssc.201702317] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 12/21/2017] [Indexed: 05/12/2023]
Abstract
Hydrogen production through facile photocatalytic water splitting is regarded as a promising strategy to solve global energy problems. Transition-metal carbides (MXenes) have recently drawn attention as potential co-catalyst candidates for photocatalysts. Here, we report niobium pentoxide/carbon/niobium carbide (MXene) hybrid materials (Nb2 O5 /C/Nb2 C) as photocatalysts for hydrogen evolution from water splitting. The Nb2 O5 /C/Nb2 C composites were synthesized by one-step CO2 oxidation of Nb2 CTx . Nb2 O5 grew homogeneously on Nb2 C after mild oxidation, during which some amorphous carbon was also formed. With an optimized oxidation time of 1.0 h, Nb2 O5 /C/Nb2 C showed the highest hydrogen generation rate (7.81 μmol h-1 gcat-1 ), a value that was four times higher than that of pure Nb2 O5 . The enhanced performance of Nb2 O5 /C/Nb2 C was attributed to intimate contact between Nb2 O5 and conductive Nb2 C and the separation of photogenerated charge carriers at the Nb2 O5 /Nb2 C interface; the results presented herein show that transition-metal carbide are promising co-catalysts for photocatalytic hydrogen production.
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Tolosa A, Fleischmann S, Grobelsek I, Quade A, Lim E, Presser V. Binder-Free Hybrid Titanium-Niobium Oxide/Carbon Nanofiber Mats for Lithium-Ion Battery Electrodes. CHEMSUSCHEM 2018; 11:159-170. [PMID: 29105356 DOI: 10.1002/cssc.201701927] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Free-standing, binder-free, titanium-niobium oxide/carbon hybrid nanofibers are prepared for Li-ion battery applications. A one-pot synthesis offers a significant reduction of processing steps and avoids the use of environmentally unfriendly binder materials, making the approach highly sustainable. Tetragonal Nb2 O5 /C and monoclinic Ti2 Nb10 O29 /C hybrid nanofibers synthesized at 1000 °C displayed the highest electrochemical performance, with capacity values of 243 and 267 mAh g-1 , respectively, normalized to the electrode mass. At 5 A g-1 , the Nb2 O5 /C and Ti2 Nb10 O29 /C hybrid fibers maintained 78 % and 53 % of the initial capacity, respectively. The higher rate performance and stability of tetragonal Nb2 O5 compared to that of monoclinic Ti2 Nb10 O29 is related to the low energy barriers for Li+ transport in its crystal structure, with no phase transformation. The improved rate performance resulted from the excellent charge propagation in the continuous nanofiber network.
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Li J, Wei B, Cao Z, Yue X, Zhang Y, Lü Z. Niobium Doped Lanthanum Strontium Ferrite as A Redox-Stable and Sulfur-Tolerant Anode for Solid Oxide Fuel Cells. CHEMSUSCHEM 2018; 11:254-263. [PMID: 28976645 DOI: 10.1002/cssc.201701638] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/30/2017] [Indexed: 06/07/2023]
Abstract
The Nb-doped lanthanum strontium ferrite perovskite oxide La0.8 Sr0.2 Fe0.9 Nb0.1 O3-δ (LSFNb) is evaluated as an anode material in a solid oxide fuel cell (SOFC). The effects of Nb partial substitution in the crystal structure, the electrical conductivity, and the valence of Fe ions are studied. LSFNb exhibits good structural stability in a severe reducing atmosphere at 800 °C, suggesting that high-valent Nb can effectively promote the stability of the lattice structure. The concentration of Fe2+ increases after Nb doping, as confirmed by X-ray photoelectron spectroscopy. The maximum power density of a thick Sc-stabilized zirconia (ScSZ) electrolyte-supported single cell reached 241.6 mW cm-2 at 800 °C with H2 as fuel. The cell exhibited excellent stability for 100 h continuous operation without detectable degeneration. Scanning electron microscopy clearly revealed exsolution on the LSFNb surface after operation. Meanwhile, LSFNb particles agglomerated significantly during long-term stability testing. Impedance spectra suggested that both the LSFNb anode and the (La0.75 Sr0.25 )0.95 MnO3-δ /ScSZ cathode underwent an activation process during long-term testing, through which the charge transfer ability increased significantly. Meanwhile, low-frequency resistance (RL ) mainly attributed to the anode (80 %) significantly increased, probably due to the agglomeration of LSFNb particles. The LSFNb anode exhibits excellent anti-sulfuring poisoning ability and redox stability. These results demonstrate that LSFNb is a promising anode material for SOFCs.
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El Fergani M, Candu N, Coman SM, Parvulescu VI. Nb-Based Zeolites: Efficient bi-Functional Catalysts for the One-Pot Synthesis of Succinic Acid from Glucose. Molecules 2017; 22:E2218. [PMID: 29240713 PMCID: PMC6149682 DOI: 10.3390/molecules22122218] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/08/2017] [Accepted: 12/12/2017] [Indexed: 11/16/2022] Open
Abstract
The one-pot production of succinic acid from glucose was investigated in pure hot water as solvent using Nb (0.02 and 0.05 moles%)-Beta zeolites obtained by a post-synthesis methodology. Structurally, they are comprised of residual framework Al-acid sites, extra-framework isolated Nb (V) and Nb₂O₅ pore-encapsulated clusters. The Nb-modified Beta-zeolites acted as bi-functional catalysts in which glucose is dehydrated to levulinic acid (LA) which, further, suffers an oxidation process to succinic acid (SA). After the optimization of the reaction conditions, that is, at 180 °C, 18 bar O₂, and 12 h reaction time, the oxidation of glucose occurred with a selectivity to succinic acid as high as 84% for a total conversion.
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Snyder SF, Eckerman KF. The Dosimetric Demise of 97MNB. HEALTH PHYSICS 2017; 113:527-528. [PMID: 28915138 DOI: 10.1097/hp.0000000000000719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Radionuclide differences between ICRP Publication 38 and its succeeding work, ICPR Publication 107, are reviewed. The specific example of the isomer Nb is discussed, examining how dose reporting for this nuclide can be an issue.
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Ghosh M, Swain KK, Verma R. Interaction of niobium with iron-oxide colloids and the role of humic acid. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:101-109. [PMID: 28803000 DOI: 10.1016/j.jenvrad.2017.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 06/07/2023]
Abstract
In this work, we report the sorption of Nb on iron oxides and the effect of humic acid. Iron oxides viz. goethite, hematite and magnetite were chemically synthesised and characterised by X-ray diffraction, particle size, surface area and zeta potential measurement. The sorption of Nb on all the three iron oxides was low (∼40%) at pH 1, increased to ∼ 90% at pH 8 and decreased marginally above pH 8. The effect of humic acid on the sorption was very small. Thermodynamic parameters viz. activation energy, enthalpy, entropy, free energy and sticking probability were calculated to understand the mechanism of the sorption process. Although the enthalpy was positive, the free energy change was negative i.e. the sorption was entropy driven process. The sorption followed pseudo-second-order kinetics and sticking probability model indicated that the process was chemisorption. This study is important to understand the probable migration of 94Nb (half life 20300 y) during underground storage of radioactive waste.
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Zhao XL, Li L, Niinomi M, Nakai M, Zhang DL, Suryanarayana C. Metastable Zr-Nb alloys for spinal fixation rods with tunable Young's modulus and low magnetic resonance susceptibility. Acta Biomater 2017; 62:372-384. [PMID: 28827184 DOI: 10.1016/j.actbio.2017.08.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 12/01/2022]
Abstract
Good ductility, low magnetic susceptibility, and tunable Young's modulus are highly desirable properties for materials usage as spinal fixation rods. In this study, the effects of niobium content on the microstructure, magnetic susceptibility, and mechanical properties of Zr-xNb (13≤x≤23wt%) alloys were investigated. For the Zr-15Nb and Zr-17Nb alloys, a remarkable increase in Young's modulus was achieved due to the occurrence of deformation-induced ω phase transformation. This was the result of the competition of two factors associated with the Nb content: an increase of the stability of β phase and a decrease of the amount of athermal ω phase with increasing Nb content. When the Nb content was 15% or 17%, the amount of deformation-induced ω phase was maximum. Moreover, the magnetic susceptibility decreased with the deformation-induced β→ω phase transformation, and the Zr-17Nb alloy with apparent kink bands exhibited a smaller amount of springback than the Zr-15Nb alloy with {332} 〈113〉 mechanical twins. Furthermore, the ions released from the Zr-xNb alloys in accelerated immersion tests were at a very low level. The combination of low initial Young's modulus, and its remarkable variation induced by deformation, low magnetic susceptibility, good ductility, and smaller springback make the Zr-17Nb alloy a potential candidate for spinal fixation rods. STATEMENT OF SIGNIFICANCE For the rods of spinal fixation devices, it is important but difficult to lower the springback for bending formativeness while keeping the low initial Young's modulus for biocompatibility and lower the magnetic susceptibility for postoperative examination simultaneously. In this study, Zr-17Nb alloy was successfully developed via deformation-induced ω phase transformation during loading, simultaneously meeting the abovementioned properties for spinal fixation rods.
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