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Synthesis and enhanced antioxidant and membrane-protective activity of curcumin@AlOOH nanoparticles.Journal of Inorganic Biochemistry Sep 2020The ever increasing demand for nanoantioxidants with minimized toxicity dictates the necessity to develop new biocompatible materials. One promising approach is the...
The ever increasing demand for nanoantioxidants with minimized toxicity dictates the necessity to develop new biocompatible materials. One promising approach is the immobilization of polyphenols on metal (oxy)hydroxide nanoparticles (NPs) that possess the desired chemical and colloidal stability while also allowing to dispose of the antioxidants more safely and effectively. In this paper we modify sol-gel synthesized γ-AlOOH NPs with curcumin molecules. The prepared colloidal systems are hydrosols, stable in acidic, neutral and slightly basic pH values. UV-vis and FTIR spectroscopies suggest that the mechanism of curcumin binding lies in the H-bonding of its functional groups to hydroxyls of pseudoboemite. Modification of AlOOH nanoparticles shifts its isoelectric point from 9.7 to 9.3 due to the weak acidic centers of the polyphenol. Immobilization of curcumin molecules on pseudoboehmite allows to achieve good solubility of the phenol in water and to reduce the level of its hemolytic activity (indicating good biocompatibility). At the same time, it preserves radical scavenging activity and in some experimental designs even enhances antioxidant and membrane-protective activity (enhancement ≥30%) in vitro on cellular and non-cellular models.
Topics: Aluminum Hydroxide; Aluminum Oxide; Animals; Antioxidants; Curcumin; Drug Carriers; Erythrocyte Membrane; Hemolysis; Metal Nanoparticles; Mice; Oxidative Stress
PubMed: 32652264
DOI: 10.1016/j.jinorgbio.2020.111168 -
Journal of Environmental Radioactivity Sep 2019Kinetics analyses of sorption and desorption provide important insight into reaction mechanisms occurring at the mineral-water interface. They are also needed to...
Kinetics analyses of sorption and desorption provide important insight into reaction mechanisms occurring at the mineral-water interface. They are also needed to determine when equilibrium is achieved, identify intermediate chemical species, and inform models describing neptunium mobility. Neptunium sorption to and desorption from four different aluminum (hydr)oxides - bayerite (α-Al(OH)), gibbsite (γ-Al(OH)), corundum (α-AlO), and γ-alumina (γ-AlO) - were investigated as a function of mineral concentration (5 - 170 m L), neptunium concentration (10 - 10 M), and pH (5.5 - 10.5). Neptunium sorption was characterized by a two-step reaction with an initial fast sorption step occurring within minutes followed by a slower equilibrium process, which was attributed to initial sorption of neptunium to a small number of strong sorption sites followed by sorption of neptunium to a larger number of weak sorption sites. The kinetics data were modeled using the linear and non-linear forms of the pseudo-first and pseudo-second order rate equations and the goodness of fit parameters were compared. Non-linear pseudo-second order rate constants described neptunium sorption to aluminum (hydr)oxides most accurately and were used to determine the reaction orders with respect to mineral concentration and [H]. Neptunium desorption experiments demonstrated that the desorption mechanism changed as a function of pH and that the forward and reverse reactions were not equivalent. At pH ≥ 7.5, desorption reached steady-state within an hour and was accurately described by the non-linear pseudo-second order rate equations. A desorption plateau was observed at pH 5.5 that could not be described by either pseudo-first or -second order kinetics, suggesting the possibility of a multi-step desorption reaction. The comparatively slow desorption kinetics observed here suggests that sorbed neptunium could be slowly released back into the aqueous phase and act as a continuous source of contamination to the environment.
Topics: Adsorption; Aluminum Hydroxide; Aluminum Oxide; Hydrogen-Ion Concentration; Kinetics; Minerals; Neptunium
PubMed: 31121423
DOI: 10.1016/j.jenvrad.2019.05.006 -
Environmental Science and Pollution... Jan 2023Productivity, distillate exergy, and energy efficiency of the conventional passive single-basin double-slope solar still is minimum, due to low evaporation and...
Productivity, distillate exergy, and energy efficiency of the conventional passive single-basin double-slope solar still is minimum, due to low evaporation and condensation rate. This research article attempts to increase the production rate, distillate exergy, and energy efficiency of the single-basin glasswool-insulated double-slope solar still by attaching novel solar-operated vacuum fan, external condenser and adding 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid. Inclusion of vacuum fan and external condenser enhances the production rate in the modified solar still. It is evident that as the vacuum fan exhales the vapour in the basin, the temperature of water in the basin and transparent glass are reduced significantly and so the vaporization amount increases considerably. It makes that a large amount of vapour is extracted by the vacuum fan and allowed to pass though the condenser, and therefore, the entire condensate of the solar still is increased significantly. To attain a comparative study, conventional and modified double-slope solar still of identical dimensions were developed utilizing aluminium and an experimental investigation carried out during the peak of summer. The inclusion of solar-operated vacuum fan and external condenser in the modified glasswool insulated double-slope solar still enhances the maximum energy efficiency, exergy efficiency, and cumulative production by 28.37%, 78.60%, and 64.29% due to enhancement in the evaporation rate of liquid in the solar still basin. Also, the addition of 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid in the conventional double-slope solar still possess the maximum increase in the energy efficiency and exergy efficiency by 20.96%, 18.01%, 10.76% and 52.53%, 38.52%, 30.35% as compared to conventional solar still without nanofluid. It is primarily due to increase in the thermal conductivity and radiative property of nanofluid. The result also signifies that the addition of 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid in the modified double-slope solar still possess the maximum enhancement in the energy efficiency and exergy efficiency by 21.33%, 19.36%, 17.03% and 50.11%, 36.82%, 23.75% as compared to modified solar still without nanofluid. Combined effect of using solar-operated vacuum fan, water cooled condenser, and 0.1% volume concentration of copper oxide, aluminium oxide, and zinc oxide nanofluid in the double-slope solar still enhances the maximum production rate and cumulative production by 59.26%, 55.56%, 51.85% and 96.43%, 82.14%, 75% as compared to conventional double-slope solar still. Among the three different nanofluids, the copper oxide nanofluid produced the highest cumulative production, energy efficiency, and exergy efficiency.
Topics: Copper; Zinc Oxide; Vacuum; Water; Aluminum Oxide
PubMed: 36117223
DOI: 10.1007/s11356-022-22919-8 -
Colloids and Surfaces. B, Biointerfaces Dec 2022The research was focused on alternative treatment techniques, separating immediate and long-term reconstruction stages. The work involved development of ceramic...
The research was focused on alternative treatment techniques, separating immediate and long-term reconstruction stages. The work involved development of ceramic materials dedicated to reconstruction of the temporomandibular joint area. They were based on alumina (aluminum oxide) and characterized by varying porosities. A broad spectrum of studies was conducted to test the proposed material and determine its suitability for mandibular reconstruction. They compared the effects of substrate properties of ceramic materials in terms of biocompatibility, microbiology and systemic toxicity in in vivo studies. Finally it was concluded that Alumina LithaLox 350D is best suited for jawbone implants.
Topics: Humans; Ceramics; Aluminum Oxide; Bone and Bones; Anti-Bacterial Agents; Neoplasms; Materials Testing
PubMed: 36274400
DOI: 10.1016/j.colsurfb.2022.112943 -
Science Bulletin Jun 2023
Topics: Aluminum Oxide; Magnesium Oxide; Magnetic Phenomena
PubMed: 37211488
DOI: 10.1016/j.scib.2023.05.003 -
Journal of Nanoscience and... Feb 2015Aluminum is one of the most widely used nonferrous metals and an important industrial material, especially for automotive coatings. However, potential toxicity caused by...
Aluminum is one of the most widely used nonferrous metals and an important industrial material, especially for automotive coatings. However, potential toxicity caused by aluminum in humans limits the used of this metal. α-alumina is the most stable form of aluminum in various phases. Although the results of studies evaluating the dermal toxicity of α-alumina remained unclear, this compound can still be used as a pigment in cosmetics for humans. In the current study, we further evaluated the dermal cytotoxic effects of α-alumina on human skin cells and an in vivo mouse model. We also measured the in vitro penetration profile of flake-like α-alumina in porcine skin and assessed the degree of cellular metabolic disorders. Our findings demonstrated that treatment with flake-like α-alumina did not significantly affect cell viability up to 24 h. This compound was found to have a non-penetration profile based on a Franz modified diffusion cell assay. In addition, flake-like α-alumina was not found to induce dermal inflammation as assessed by histology of epidermal architecture, hyperplasia, and the expression of Interleukin-1β and Cyclooxygenase-2. Results of the cellular metabolic disorder assay indicated that flake-like α-alumina does not exert a direct effect on human skin cells. Taken together, our findings provided not only evidence that flake-like α-alumina may serve as a pearlescent pigment in cosmetics but also experimental basis utilizing α-alumina for human application. Our results also obviously provide new insight of the further toxicity study to aluminum based nanoparticles for skin.
Topics: Aluminum Oxide; Cell Survival; Cells, Cultured; Coloring Agents; Dermatitis, Contact; Dose-Response Relationship, Drug; Fibroblasts; Humans; Materials Testing; Skin
PubMed: 26353706
DOI: 10.1166/jnn.2015.9607 -
Orthodontics & Craniofacial Research Aug 2023Three-dimensional (3D) printing technology is a promising manufacturing technique for fabricating ceramic brackets. The aim of this research was to assess fundamental...
OBJECTIVES
Three-dimensional (3D) printing technology is a promising manufacturing technique for fabricating ceramic brackets. The aim of this research was to assess fundamental mechanical properties of in-office, 3D printed ceramic brackets.
MATERIALS AND METHODS
3D-printed zirconia brackets, commercially available polycrystalline alumina ceramic brackets (Clarity, 3 M St. Paul, MN) and 3D-printed customized polycrystalline alumina ceramic ones (LightForce™, Burlington, Massachusetts) were included in this study. Seven 3D printed zirconia brackets and equal number of ceramic ones from each manufacturer underwent metallographic grinding and polishing followed by Vickers indentation testing. Hardness (HV) and fracture toughness (K1c) were estimated by measuring impression average diagonal length and crack length, respectively. After descriptive statistics calculation, group differences were analysed with 1 Way ANOVA and Holm Sidak post hoc multiple comparison test at significance level α = .05.
RESULTS
Statistically significant differences were found among the materials tested with respect to hardness and fracture toughness. The 3D-printed zirconia proved to be less hard (1261 ± 39 vs 2000 ± 49 vs 1840 ± 38) but more resistant to crack propagation (K1c = 6.62 ± 0.61 vs 5.30 ± 0.48 vs 4.44 ± 0.30 MPa m ) than the alumina brackets (Clarity and Light Force respectivelty). Significant differences were observed between the 3D printed and the commercially available polycrystalline alumina ceramic brackets but to a lesser extent.
CONCLUSIONS
Under the limitations of this study, the 3D printed zirconia bracket tested is characterized by mechanical properties associated with advantageous orthodontic fixed appliances traits regarding clinically relevant parameters.
Topics: Hardness; Materials Testing; Ceramics; Aluminum Oxide; Surface Properties
PubMed: 36648375
DOI: 10.1111/ocr.12632 -
International Journal of Molecular... Mar 2023This work represents research into materials designed to improve the environment. The study was carried out on aluminum hydroxide xerogels and alumina catalysts obtained...
This work represents research into materials designed to improve the environment. The study was carried out on aluminum hydroxide xerogels and alumina catalysts obtained by the Controlled Double Jet Precipitation (CDJP) process at different pH values. It has been shown that the pH of the CDJP process determines the content of aluminum-bound nitrate ions in the aluminum hydroxide. These ions are removed at a higher temperature than the decomposition of ammonium nitrate. The high content of aluminum-bound nitrate ions determines the structural disorder of the alumina and the high content of the penta-coordinated alumina catalyst.
Topics: Aluminum Oxide; Nitrates; Aluminum Hydroxide; Aluminum; Spectroscopy, Fourier Transform Infrared
PubMed: 36982226
DOI: 10.3390/ijms24065151 -
Journal of Orthopaedic Surgery and... Mar 2023The objective of this prospective randomized monocentric study is to compare the speed and quality of interbody fusion of implanted porous AlO (aluminium oxide) cages... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The objective of this prospective randomized monocentric study is to compare the speed and quality of interbody fusion of implanted porous AlO (aluminium oxide) cages with PEEK (polyetheretherketone) cages in ACDF (anterior cervical discectomy and fusion).
MATERIALS AND METHODS
A total of 111 patients were enrolled in the study, which was carried out between 2015 and 2021. The 18-month follow-up (FU) was completed in 68 patients with an AlO cage and 35 patients with a PEEK cage in one-level ACDF. Initially, the first evidence (initialization) of fusion was evaluated on computed tomography. Subsequently, interbody fusion was evaluated according to the fusion quality scale, fusion rate and incidence of subsidence.
RESULTS
Signs of incipient fusion at 3 months were detected in 22% of cases with the AlO cage and 37.1% with the PEEK cage. At 12-month FU, the fusion rate was 88.2% for AlO and 97.1% for PEEK cages, and at the final FU at 18 months, 92.6% and 100%, respectively. The incidence of subsidence was observed to be 11.8% and 22.9% of cases with AlO and PEEK cages, respectively.
CONCLUSIONS
Porous AlO cages demonstrated a lower speed and quality of fusion in comparison with PEEK cages. However, the fusion rate of AlO cages was within the range of published results for various cages. The incidence of subsidence of AlO cages was lower compared to published results. We consider the porous AlO cage as safe for a stand-alone disc replacement in ACDF.
Topics: Humans; Porosity; Prospective Studies; Diskectomy; Aluminum Oxide; Ketones; Polyethylene Glycols
PubMed: 36869376
DOI: 10.1186/s13018-023-03625-8 -
Environmental Science and Pollution... Jul 2016Bauxite residue is a hazardous solid waste produced during the production of alumina. Its high alkalinity is a potential threat to the environment which may disrupt the... (Review)
Review
Bauxite residue is a hazardous solid waste produced during the production of alumina. Its high alkalinity is a potential threat to the environment which may disrupt the surrounding ecological balance of its disposal areas. China is one of the major global producers of alumina and bauxite residue, but differences in alkalinity and associated chemistry exist between residues from China and those from other countries. A detailed understanding of the chemistry of bauxite residue remains the key to improving its management, both in terms of minimizing environmental impacts and reducing its alkaline properties. The nature of bauxite residue and the chemistry required for its transformation are still poorly understood. This review focuses on various transformation processes generated from the Bayer process, sintering process, and combined Bayer-sintering process in China. Problems associated with transformation mechanisms, technical methods, and relative merits of these technologies are reviewed, while current knowledge gaps and research priorities are recommended. Future research should focus on transformation chemistry and its associated mechanisms and for the development of a clear and economic process to reduce alkalinity and soda in bauxite residue.
Topics: Aluminum Oxide; China; Hydrogen-Ion Concentration; Industrial Waste; Waste Management
PubMed: 27023808
DOI: 10.1007/s11356-016-6478-7