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1.
Int J Biol Macromol ; 266(Pt 1): 131158, 2024 May.
Article in English | MEDLINE | ID: mdl-38552682

ABSTRACT

Spray-dried niobium oxide coated with chitosan-activated carbon (NIC) was synthesized and used to remove doxorubicin hydrochloride and crystal violet from aqueous solutions under different parameters such as solution pH (2, 4, 6, and 8), contact time (1 to 9 h), initial concentration (20 to 200 mg L-1), and competing ions (0.1 M of CaCl2 and NaCl). The addition of 5 % chitosan-activated carbon to the matrix of niobium oxide slightly increased the specific surface area from 26 to 30 m2 g-1, with the introduction of a carboxylic functional group. This led to an increase in the amount of adsorbed doxorubicin hydrochloride (DOH) from 30 to 44 mg g-1 and that of crystal violet (CV) from 15 to 32 mg g-1 from the initial respective 100 mg L-1 at pH 8. The data from the concentration study fitted into Liu isotherm having adsorption capacity of 128 and 57 mg g-1 for DOH and CV respectively, while pseudo first and second order are more suitable for adsorption kinetics. The additional functional groups on the IR spectrum of NIC after the adsorption of DOH and CV confirmed the interaction between NIC and the adsorbates' molecules. The mechanism of adsorption was supported by DFT calculations.


Subject(s)
Chitosan , Doxorubicin , Gentian Violet , Niobium , Chitosan/chemistry , Doxorubicin/chemistry , Adsorption , Niobium/chemistry , Gentian Violet/chemistry , Hydrogen-Ion Concentration , Charcoal/chemistry , Kinetics , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/isolation & purification , Density Functional Theory , Oxides/chemistry , Water/chemistry , Solutions , Water Purification/methods
2.
J Environ Sci Health B ; 59(2): 50-61, 2024.
Article in English | MEDLINE | ID: mdl-38054847

ABSTRACT

In this work, a comparison was made between the synthesis of niobium-based materials (Nb2O5), both in terms of material characterization and catalytic performance. The methods used were chemical mixtures: modified sol-gel and Pechini. The materials were calcined at different temperatures (753, 873 and 993K) and characterized by the following techniques: photoacousticspectroscopy (PAS), zero charge point (pHPZC), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA/DTG) and X-ray diffraction (XRD). The photocatalytic process was carried out to evaluate the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV radiation (250 W mercury vapor lamp) and different experimental conditions. In addition, to better understand the influence of parameters such as pH, catalyst concentration (0.2, 0.5 and 0.8 g L-1) and calcination temperature, a Design of Experiments (DoE) was used. The results indicated that despite having similar structures and phases in the XRD analysis, the morphology presents two distinct surfaces, due to the preparation method. Differences in the synthesis method affected the catalytic activity in the parameters studied. Although the zero charge point values are close (6.18-6.36), we observed differences in the band gap depending on the calcination temperature. In the optimal condition studied, the catalyst prepared by the sol-gel method obtained the best results.


Subject(s)
Herbicides , Niobium/chemistry , Ultraviolet Rays , Microscopy, Electron, Scanning , 2,4-Dichlorophenoxyacetic Acid
3.
Molecules ; 28(13)2023 Jun 22.
Article in English | MEDLINE | ID: mdl-37446574

ABSTRACT

The reactions between catechol (H2cat) and niobium(V) or tantalum(V) precursors in basic aqueous solutions lead to the formation of catecholate complexes of different natures. The following complexes were isolated and characterized by single-crystal X-ray diffraction (SCXRD): (1) (NH4)3[NbO(cat)3]∙4H2O; (2) K2[Nb(cat)3(Hcat)]·2H2cat·2H2O; (3) Cs3[NbO(cat)3]·H2O; (4) (NH4)4[Ta2O(cat)6]·3H2O; (5) Cs2[Ta(cat)3(Hcat)]·H2cat; (6) Cs4[Ta2O(cat)6]·7H2O. The isolated crystalline products were characterized by elemental analysis, X-ray powder diffraction (XRPD), FTIR, and TGA. The structural features of these complexes, such as {Ta2O} unit geometry, Cs-π interactions, and crystal packing effects, are discussed.


Subject(s)
Niobium , Tantalum , Niobium/chemistry , Tantalum/chemistry , Crystallography, X-Ray
4.
J Environ Radioact ; 264: 107201, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37167644

ABSTRACT

Zr-Nb alloy is used as the pressure tube in pressurized heavy water reactors (PHWR). Prolonged neutron irradiation of the pressure tubes leads to the formation of a long-lived radioisotope 94Nb. Thus, the discharged pressure tubes possess huge 94Nb activity which persists for a prolonged period.If these discharged pressure tubes come in contact with ground water, 94Nb isotope may leach and migrate and this can lead to a long-term radiological impact in the environment.In the present study, we have explored the capability of laterite as a filler material for the containment and retarding the migration of 94Nb. In this regard, detailed characterization of the laterite soil was carried out using energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), fourier transform infra-red spectrometry (FTIR), total cation exchange capacity determination, zeta potential measurement and thermogravimetric analysis (TGA). The sorption study of 94Nb on laterite was carried and the effects of different physico-chemical parameters like pH, ionic strength, temperature and equilibration time were evaluated. Ionic strength, temperature and time dependent sorption studies assist to explore the probable sorption mechanism of 94Nb on laterite, which helps in understanding the migration behaviour of 94Nb in natural aquatic environment. This study suggests that laterite is a promising material in containment of 94Nb isotope owing to its good cation exchange behaviour in the acidic medium and ability to form surface complex in the neutral medium.


Subject(s)
Niobium , Radiation Monitoring , Niobium/chemistry , Soil , Temperature , Cations , Adsorption , Hydrogen-Ion Concentration , Kinetics
5.
Environ Sci Pollut Res Int ; 30(26): 68477-68488, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37126169

ABSTRACT

This work presents the synthesis of SiO2/Nb2O5 and SiO2/ZnS heterostructures using the microwave-assisted hydrothermal (MAH) method, which is fast and has low temperature. The silica used in the synthesis was obtained by burning the rice husk without any pre- or post-treatments. The obtained samples were characterized using various techniques such as X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and UV-visible. The obtained silica was found to be amorphous, and the materials used for modification showed characteristic of the type of synthesis used. SEM images showed that Nb2O5 and ZnS interacted with the SiO2 surface, filling the voids. In the photocatalytic process, the heterostructures showed enhanced decolorization efficiency for dyes such as rhodamine B (RhB) and methylene blue (MB) compared to SiO2. For RhB, the silica decolorized approximately 24%, and for MB, it discolored approximately 27%; SiO2/Nb2O5 showed 91.24% decolorization efficiency for RhB and 72.77% MB, while SiO2/ZnS showed approximately 96% for RhB and 100% for MB. All samples were tested under the same conditions. This demonstrates that the use of rice husk residue not only improves the photocatalytic activity of heterostructures but also promotes the utilization of improperly discarded residues.


Subject(s)
Oryza , Silicon Dioxide , Silicon Dioxide/chemistry , Niobium/chemistry , Zinc Compounds
6.
Chemistry ; 29(33): e202300614, 2023 Jun 13.
Article in English | MEDLINE | ID: mdl-37013359

ABSTRACT

A precise investigation of NbO has been carried out by advanced electron microscopy combined with powder and single crystal X-ray diffraction (XRD). The structure of pristine NbO has been determined as Pm-3 m space group (SG) with a = 4.211 Šand the positions of Nb and O at the 3c and 3d Wyckoff positions, respectively, which is consistent with previous report based on powder XRD data. Electron beams induced a structural transition, which was investigated and explained by combining electron diffraction and atomic-resolution imaging. The results revealed that the electron beam stimulated both Nb and O atom-migrations within each fcc sublattice, and that the final structure was SG Fm-3 m with a = 4.29 Å, Nb and O at the 4a and 4b with 75 % occupancy and same chemical composition. Antiphase planar defects were discovered in the pristine NbO and related to the structural transformation. Theoretical calculations performed by density functional theory (DFT) supported the experimental conclusions.


Subject(s)
Electrons , Niobium , Niobium/chemistry , Powders , Crystallography, X-Ray , Microscopy, Electron
7.
J Colloid Interface Sci ; 643: 600-612, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37003869

ABSTRACT

Engineering the nanostructure of an electrocatalyst is crucial in developing a high-performance electrochemical sensor. This work exhibits the hydrothermal followed by annealing synthesis of niobium oxide/niobium carbide/reduced graphene oxide (NbO/NbC/rGO) ternary nanocomposite. The oval-shaped NbO/NbC nanoparticles cover the surface of rGO evenly, and the rGO nanosheets are interlinked to produce a micro-flower-like architecture. The NbO/NbC/rGO nanocomposite-modified electrode is presented here for the first time for the rapid and sensitive electrochemical detection of the anticancer drug methotrexate (MTX). Down-sized NbO/NbC nanoparticles and rGO's high surface area provide many active sites with a rapid electron transfer rate, making them ideal for MTX detection. In comparison to previously reported MTX sensors, the developed drug sensor exhibits a lower oxidation potential and a higher peak current responsiveness. The constructed sensors worked analytically well under optimal conditions, as shown by a low detection limit of 1.6 nM, a broad linear range of 0.1-850 µM, and significant recovery findings (∼98 %, (n = 3)) in real samples analysis. Thus, NbO/NbC/rGO nanocomposite material for high-performance electrochemical applications seems promising.


Subject(s)
Antineoplastic Agents , Graphite , Nanocomposites , Oxides/chemistry , Niobium/chemistry , Methotrexate , Electrochemical Techniques , Graphite/chemistry , Nanocomposites/chemistry
8.
Int J Mol Sci ; 24(6)2023 Mar 09.
Article in English | MEDLINE | ID: mdl-36982320

ABSTRACT

Dental implants have emerged as one of the most consistent and predictable treatments in the oral surgery field. However, the placement of the implant is sometimes associated with bacterial infection leading to its loss. In this work, we intend to solve this problem through the development of a biomaterial for implant coatings based on 45S5 Bioglass® modified with different amounts of niobium pentoxide (Nb2O5). The structural feature of the glasses, assessed by XRD and FTIR, did not change in spite of Nb2O5 incorporation. The Raman spectra reveal the Nb2O5 incorporation related to the appearance of NbO4 and NbO6 structural units. Since the electrical characteristics of these biomaterials influence their osseointegration ability, AC and DC electrical conductivity were studied by impedance spectroscopy, in the frequency range of 102-106 Hz and temperature range of 200-400 K. The cytotoxicity of glasses was evaluated using the osteosarcoma Saos-2 cells line. The in vitro bioactivity studies and the antibacterial tests against Gram-positive and Gram-negative bacteria revealed that the samples loaded with 2 mol% Nb2O5 had the highest bioactivity and greatest antibacterial effect. Overall, the results showed that the modified 45S5 bioactive glasses can be used as an antibacterial coating material for implants, with high bioactivity, being also non-cytotoxic to mammalian cells.


Subject(s)
Dental Implants , Animals , Niobium/chemistry , Anti-Bacterial Agents/chemistry , Gram-Negative Bacteria , Gram-Positive Bacteria , Biocompatible Materials/pharmacology , Biocompatible Materials/chemistry , Glass/chemistry , Ceramics/chemistry , Mammals
9.
Int J Mol Sci ; 24(2)2023 Jan 14.
Article in English | MEDLINE | ID: mdl-36675171

ABSTRACT

Titanium beta alloys represent the new generation of materials for the manufacturing of joint implants. Their Young's modulus is lower and thus closer to the bone tissue compared to commonly used alloys. The surface tribological properties of these materials should be improved by ion implantation. The influence of this surface treatment on corrosion behaviour is unknown. The surface of Ti-36Nb-6Ta, Ti-36Nb-4Zr, and Ti-39Nb titanium ß-alloys was modified using nitrogen ion implantation. X-ray photoelectron spectroscopy was used for surface analysis, which showed the presence of titanium, niobium, and tantalum nitrides in the treated samples and the elimination of less stable oxides. Electrochemical methods, electrochemical impedance spectra, polarisation resistance, and Mott-Schottky plot were measured in a physiological saline solution. The results of the measurements showed that ion implantation does not have a significant negative effect on the corrosion behaviour of the material. The best results of the alloys investigated were achieved by the Ti-36Nb-6Ta alloy. The combination of niobium and tantalum nitrides had a positive effect on the corrosion resistance of this alloy. After surface treatment, the polarization resistance of this alloy increased, 2.3 × 106 Ω·cm2, demonstrating higher corrosion resistance of the alloy. These results were also supported by the results of electrochemical impedance spectroscopy.


Subject(s)
Alloys , Titanium , Titanium/chemistry , Alloys/chemistry , Niobium/chemistry , Tantalum/chemistry , Electrochemical Techniques , Corrosion , Surface Properties , Materials Testing
10.
Orthod Craniofac Res ; 26(3): 442-450, 2023 Aug.
Article in English | MEDLINE | ID: mdl-36533534

ABSTRACT

OBJECTIVES: White spot lesions (WSL) are prevalent in patients using orthodontic appliances. The presence of ion-releasing compounds in the tooth-appliance interface may limit enamel demineralization to control WSL incidence. Thus, this study aims to evaluate the mineral formation on SiNb-containing experimental orthodontic resins and the influence of these fillers on the physicochemical and biological properties of developed materials. MATERIALS AND METHODS: The SiNb particles were synthesized via the sol-gel route and characterized by their molecular structure and morphology. Photopolymerizable orthodontic resins were produced with a 75 wt% Bis-GMA/25 wt% TEGDMA and 10 wt%, 20 wt%, or 30 wt% addition of SiNb. A control group was formulated without SiNb. These resins were tested for their degree of conversion, softening in solvent, cytotoxicity in fibroblasts, flexural strength, shear bond strength (SBS), and mineral deposition. RESULTS: The addition of 10 wt% of SiNb did not impair the conversion of monomers, cytotoxicity, and flexural strength. All groups with SiNb addition presented similar softening in solvent. The presence of these particles did not affect the bond strength between metallic brackets and enamel, with SBS values ranging from 16.41 to 18.66 MPa. The mineral deposition was observed for all groups. CONCLUSION: The use of niobium silicate as filler particles in resins may be a strategy for the adhesion of orthodontic appliances. The 10 wt% SiNb concentration resulted in a material with suitable physicochemical and biological properties while maintaining the bond strength to tooth enamel and promoting mineral deposition.


Subject(s)
Dental Bonding , Orthodontic Brackets , Humans , Niobium/chemistry , Silicates , Bisphenol A-Glycidyl Methacrylate/chemistry , Orthodontic Appliances , Solvents , Materials Testing , Shear Strength , Resin Cements/chemistry
11.
Angew Chem Int Ed Engl ; 61(51): e202212164, 2022 12 19.
Article in English | MEDLINE | ID: mdl-36240785

ABSTRACT

The production of conjugated C4-C5 dienes from biomass can enable the sustainable synthesis of many important polymers and liquid fuels. Here, we report the first example of bimetallic (Nb, Al)-atomically doped mesoporous silica, denoted as AlNb-MCM-41, which affords quantitative conversion of 2-methyltetrahydrofuran (2-MTHF) to pentadienes with a high selectivity of 91 %. The incorporation of AlIII and NbV sites into the framework of AlNb-MCM-41 has effectively tuned the nature and distribution of Lewis and Brønsted acid sites within the structure. Operando X-ray absorption, diffuse reflectance infrared and solid-state NMR spectroscopy collectively reveal the molecular mechanism of the conversion of adsorbed 2-MTHF over AlNb-MCM-41. Specifically, the atomically-dispersed NbV sites play an important role in binding 2-MTHF to drive the conversion. Overall, this study highlights the potential of hetero-atomic mesoporous solids for the manufacture of renewable materials.


Subject(s)
Alkadienes , Niobium , Niobium/chemistry , Aluminum , Catalysis
12.
Ambix ; 69(4): 399-419, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36250926

ABSTRACT

This paper examines the identification of chemical elements using mineral analysis, focusing on the controversy surrounding the "tantalum metals" between 1801 and 1866. Of these metals, only tantalum and niobium are still recognised as elements today; the discovery claims of columbium, pelopium, ilmenium and dianium were all retracted or refuted. Despite the theoretical and institutional changes that chemistry underwent during this time, the debates on the tantalum metals point towards a continuity in the identification of metals. For most of the nineteenth century, chemists continued to use the same types of analytical procedures as their mid-eighteenth-century predecessors. These analytical methods enabled the identification of metals based on the chemical behaviour of their compounds, without requiring their isolation in the form of simple substances (that is, as metals). Accordingly, the central questions in all of the debates on the tantalum metals were the correct identification of the properties of compounds and the elimination of impurities, rather than the simplicity of the new metals. The story of the tantalum metals therefore illustrates the fact that, despite the definition of chemical elements as simple substances, the discovery of new (metallic) elements only rarely coincided with the isolation of new simple substances.


Subject(s)
Niobium , Tantalum , Tantalum/chemistry , Niobium/chemistry , Metals , Chemistry, Analytic
13.
Article in English | MEDLINE | ID: mdl-36069164

ABSTRACT

This study describes the synthesis of Cu/Nb2O5, Fe/Nb2O5, and Cu-Fe/Nb2O5 catalysts obtained by incorporating copper and/or iron metals into niobium pentoxide (Nb2O5). The new materials were characterized by the following techniques: Thermogravimetric Analysis (TA), surface and pore analysis, X-ray diffractometry (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The catalyst was applied in the photocatalytic degradation of salicylic acid (SA). The influence of different parameters (calcined temperature, pH, and metal addition) on the photocatalytic reaction was evaluated. The results indicated that catalysts containing copper were more active and pH influenced the SA degradation process. SA removal results indicated that Cu/Nb2O5 photocatalyst presented a 1.5 fold higher degradation after 120 min in comparison to Cu-Fe/Nb2O5 and 4.6 fold higher than Fe/Nb2O5 catalyst, all them calcined at 400 °C. In tests carried out in the presence of formic acid, increasing the pH from about 3 to 7 allowed an almost 3.4-fold increase in SA degradation for the Cu-Fe/Nb2O5 catalyst calcined at 400 °C.


Subject(s)
Copper , Niobium/chemistry , Oxides/chemistry , Catalysis , Iron/chemistry , Metals , Salicylic Acid , Spectroscopy, Fourier Transform Infrared
14.
Anal Bioanal Chem ; 414(27): 7885-7895, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36136112

ABSTRACT

In this work, on the basis of an immobilized metal ion affinity chromatography enrichment strategy, a new kind of covalent organic framework (COF) material for enrichment of phosphorylated peptides and exosomes was successfully prepared in a facile method, and Ti4+ and Nb5+ were used as dual-functional ions (denoted as COF-S-S-COOH-Ti4+/Nb5+). With the advantage of unbiased enrichment towards phosphopeptides, COF-S-S-COOH-Ti4+/Nb5+ shows ultra-high selectivity (maximum molar ratio of ß-casein: BSA is 1:20,000) and low limit of detection (0.2 fmol). In addition, the material has an excellent phosphopeptide loading capacity (100 µg/mg) and reusability (at least seven times). Furthermore, applying the material to the actual sample, 4 phosphopeptides were selectively extracted from the serum of renal carcinoma patients. At the same time, exosomes with an intact structure in the serum of renal carcinoma patients were successfully isolated rapidly using this strategy. All experiments have shown that COF-S-S-COOH-Ti4+/Nb5+ exhibits exciting potential in practical applications.


Subject(s)
Carcinoma, Renal Cell , Exosomes , Kidney Neoplasms , Metal-Organic Frameworks , Caseins/chemistry , Chromatography, Affinity/methods , Exosomes/chemistry , Humans , Imidazoles , Ions , Niobium/chemistry , Phosphopeptides/analysis , Titanium/chemistry
15.
IEEE Trans Ultrason Ferroelectr Freq Control ; 69(11): 3087-3094, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35981066

ABSTRACT

We investigated the effects of alternating current poling (ACP) on the piezoelectric and dielectric properties of 3-MHz sliver mode (L13 mm × W0.10-0.25 mm × T0.48 mm) vibrators fashioned from Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (PMN-0.30PT) single crystal (SC) plate manufactured using the continuous-feeding Bridgman (CF-BM) method for cardiac probes. The ACP SC plate (L13 mm × W24 mm × T0.48 mm) exhibited ultrahigh dielectric permittivity ( εT33/ε0 ) and piezoelectric coefficient ( d33 ) of 9690 and 2920 pC/N, respectively. After array dicing, the SC slivers with widths of 0.10, 0.15, 0.20, and 0.25 mm were obtained, and their average εT33/ε0 values decreased from the SC plate εT33/ε0 by 45% (5330), 29% (6880), 19% (7840), and 15% (8240), respectively, possibly because of heat and mechanical damage during the dicing. A combination of the ACP and a postdicing direct current poling (ACP-DCP) recovered their εT33/ε0 values to 6050, 7080, 8140, and 8540, respectively. The sliver mode electromechanical coupling factors ( k'33 ) were confirmed to exceed 93% after the ACP-DCP process, which were more than 4% higher than those of DCP-DCP SC slivers. The measured impedance spectra indicated that the SC slivers with 0.10-0.20 mm in width showed no spurious mode vibration near the fundamental k'33 mode. We conclude that the ACP-DCP SC slivers maintained more enhanced piezoelectric and dielectric properties than the DCP-DCP samples. These results will have important implications for the commercial application of ACP technology to medical imaging ultrasound probes.


Subject(s)
Lead , Niobium , Niobium/chemistry , Electricity , Electric Impedance , Vibration
16.
Sci Rep ; 12(1): 11874, 2022 07 13.
Article in English | MEDLINE | ID: mdl-35831317

ABSTRACT

Ti and its alloys are the most used metallic biomaterials devices due to their excellent combination of chemical and mechanical properties, biocompatibility, and non-toxicity to the human body. However, the current alloys available still have several issues, such as cytotoxicity of Al and V and high elastic modulus values, compared to human bone. ß-type alloys, compared to α-type and (α + ß)-type Ti alloys, have lower elastic modulus and higher mechanical strength. Then, new biomedical ß-type alloys are being developed with non-cytotoxic alloying elements, such as Mo and Nb. Therefore, Ti-5Mo-xNb system alloys were prepared by argon arc melting. Chemical composition was evaluated by EDS analysis, and the density measurements were performed by Archimedes' method. The structure and microstructure of the alloys were obtained by X-ray diffraction and optical and scanning electron microscopy. Microhardness values were analyzed, and MTT and crystal violet tests were performed to assess their cytotoxicity. As the Nb concentration increases, the presence of the ß-Ti phase also grows, with the Ti-5Mo-30Nb alloy presenting a single ß-Ti phase. In contrast, the microhardness of the alloys decreases with the addition of Nb, except the Ti-5Mo-10Nb alloy, which has its microhardness increased probably due to the ω phase precipitation. Biological in-vitro tests showed that the alloys are not cytotoxic.


Subject(s)
Alloys , Niobium , Alloys/chemistry , Biocompatible Materials/chemistry , Elastic Modulus , Humans , Materials Testing , Niobium/chemistry , Titanium/chemistry , X-Ray Diffraction
17.
Biomed Mater ; 17(4)2022 06 21.
Article in English | MEDLINE | ID: mdl-35679847

ABSTRACT

Titanium-based biomedical alloys are susceptible as they are used as a substitute for human bone. In this study, titanium alloy, Ti-5Cu-x%Nb (x= 0, 5, 10, 15) (%wt) was developed by powder metallurgy route. The effect of alloying niobium with Ti-5Cu alloy and its effect on the microstructure, mechanical strength, corrosion resistance, and antibacterial properties have been evaluated. The results show that the sintered alloy has bothα-Ti and Ti2Cu phases. With increasing niobium content in the alloy,ß-Ti was also detected. Additionally, it was found that the micro-hardness and compressive strength of the studied alloy was better than commercially pure titanium (cpTi), while the Young's modulus was lower than cpTi. These properties are highly favorable for using this alloy to replicate the human cortical bone. The alloy was also tested for anticorrosive property in Ringer's solution. The antibacterial activity was also examined forStaphylococcus aureusandEscherichia colibacteria. The alloy showed promising anticorrosive and antibacterial ability.


Subject(s)
Alloys , Niobium , Alloys/chemistry , Anti-Bacterial Agents/chemistry , Corrosion , Humans , Niobium/chemistry , Titanium/chemistry
18.
J Phys Chem Lett ; 13(24): 5394-5398, 2022 Jun 23.
Article in English | MEDLINE | ID: mdl-35678737

ABSTRACT

Mechanoluminescence (ML) is a well-known phenomenon that has a wide range of applications in security monitoring, biomechanical sensing, and displays. Although several mechanisms relating to ML have been proposed, significant ambiguity persists due to the coexistence of crystal boundaries, luminescence centers, and defects within the samples, making them hard to disentangle. Here we preclude such ambiguity by using a Kr+-irradiated single crystal of lithium niobium oxide (LiNbO3) as the ML materials so that oxygen vacancies are retained to modulate the ML properties. We explore the ion concentration- and species-dependent ML properties along with the band calculations to explicitly reveal that it is the trapped electrons at the oxygen vacancies that are transferred to the conduction band under the piezopotentials of LiNbO3, which combine with holes in the valence band and emit photons. This in-depth understanding not only clarifies the long-standing obscurity of the ML mechanism but also paves a rational and scalable way for the design of advanced ML materials with superior performances.


Subject(s)
Lithium , Niobium , Lithium/chemistry , Niobium/chemistry , Oxides/chemistry , Oxygen , Photons
19.
Dent Mater ; 38(2): 431-443, 2022 02.
Article in English | MEDLINE | ID: mdl-34980490

ABSTRACT

OBJECTIVE: Guided bone regeneration (GBR) techniques use barrier membranes to augment the alveolar ridge for the site-specific growth of bone defects. However, current approaches using cast metal substructures exhibit poor adaptation to the surgical site and increased risk of infection. This study aimed to fabricate multi-functional coatings with 3D-printed porous titanium-niobium (Ti-Nb) alloy meshes to maintain space, prevent the ingrowth of fibroblasts and inhibit the colonization of bacteria for GBR. METHODS: Ti-Nb alloy meshes were prepared by selective laser melting (SLM) and used as substrates for novel surface coatings. Porous chitosan (CS)/ gelatin (G)/ doxycycline (Dox) coatings were formed on the meshes using electrophoretic deposition (EPD) and freeze-drying. The process of EPD was characterized through Fourier transform infrared spectroscopy (FT-IR), zeta potential, and particle size analysis. The cytotoxicity of the coatings was evaluated through the culture of osteoblasts and immunostaining. The antibacterial activity of the coatings was tested using inhibition zone tests against Staphylococcus aureus (S. aureus) and scanning electron microscope (SEM). The inhibition of fibroblasts infiltration and nutrients transfer properties were analyzed using immunostaining and permeability tests. RESULTS: High yield strength (567.5 ± 3.5 MPa) and low elastic modulus (65.5 ± 0.2 GPa) were achieved in Ti-Nb alloy bulk samples. The data of zeta potential, FT-IR and SEM indicated that porous spongy coatings were chemically bonded following EPD. In vitro analysis of CSGDox1 (containing Dox at 1 mg·mL-1) coating revealed its antibacterial effect and biocompatibility. Moreover, the CSGDox1 coating was proved to be effective for preventing the ingrowth of fibroblasts, whilst allowing the infiltration of nutrients. SIGNIFICANCE: This study verified that the EPD of CSGDox coatings on the 3D-printed Ti-Nb meshes can maintain space, provide antibiotic release whilst maintaining a barrier against soft-tissue growth, which is essential for the success of GBR treatment.


Subject(s)
Dental Implants , Titanium , Alloys/pharmacology , Bone Regeneration , Coated Materials, Biocompatible/chemistry , Coated Materials, Biocompatible/pharmacology , Niobium/chemistry , Printing, Three-Dimensional , Spectroscopy, Fourier Transform Infrared , Staphylococcus aureus , Titanium/chemistry
20.
Colloids Surf B Biointerfaces ; 212: 112342, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35085937

ABSTRACT

Biodegradable magnesium (Mg) based implants have considerable interest in the biomedical field as their use nullifies the necessity for implant removal surgery and avoids the long-standing adverse reaction of permanent bioimplants. The degradation resistance and biocompatibility of the Mg alloys can be improved by coating them with a suitable thin film. Here, thin films of niobium and niobium oxide were developed on the AZ31B Mg alloy by sputtering technique and their biocompatibility and corrosion resistance was examined. X-ray diffraction (XRD) and Transmission electron microscope (TEM) techniques confirmed the crystallinity of the thin films. Subsequently, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques were employed to evaluate the morphology and chemical composition of the thin film surfaces, respectively. Thin-film coated Mg alloys revealed good corrosion resistance compared to their uncoated bare counterparts in simulated body fluid (SBF). The contact angle study was performed on the coated specimens to investigate their wettability which revealed their hydrophobic character. The cell viability studies on thin-film coated specimens exhibited significant cell proliferation, and cell morphological studies showed good cell attachment and growth. The in vitro MTT assay on mouse osteoblast precursor cells (MC3T3-E1) indicated that the Nb-based coatings are cytocompatible and promote cell proliferation.


Subject(s)
Absorbable Implants , Niobium , Alloys/chemistry , Alloys/pharmacology , Animals , Coated Materials, Biocompatible/chemistry , Corrosion , Materials Testing , Mice , Niobium/chemistry , Oxides
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