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Dental Materials : Official Publication... Mar 2016This study evaluated the effect of addition of alumina particles (polycrystalline or monocrystalline), with or without silica coating, on the optical and mechanical...
OBJECTIVES
This study evaluated the effect of addition of alumina particles (polycrystalline or monocrystalline), with or without silica coating, on the optical and mechanical properties of a porcelain.
METHODS
Groups tested were: control (C), polycrystalline alumina (PA), polycrystalline alumina-silica (PAS), monocrystalline alumina (MA), monocrystalline alumina-silica (MAS). Polycrystalline alumina powder was synthesized using a polymeric precursor method; a commercially available monocrystalline alumina powder (sapphire) was acquired. Silica coating was obtained by immersing alumina powders in a tetraethylorthosilicate solution, followed by heat-treatment. Electrostatic stable suspension method was used to ensure homogenous dispersion of the alumina particles within the porcelain powder. The ceramic specimens were obtained by heat-pressing. Microstructure, translucency parameter, contrast ratio, opalescence index, porosity, biaxial flexural strength, roughness, and elastic constants were characterized.
RESULTS
A better interaction between glass matrix and silica coated crystalline particles is suggested in some analyses, yet further investigation is needed to confirm it. The materials did not present significant differences in biaxial flexural strength, due to the presence of higher porosity in the groups with alumina addition. Elastic modulus was higher for MA and MAS groups. Also, these were the groups with optical qualities and roughness closer to control. The PA and PAS groups were considerably more opaque as well as rougher.
SIGNIFICANCE
Porcelains with addition of monocrystalline particles presented superior esthetic qualities compared to those with polycrystalline particles. In order to eliminate the porosity in the ceramic materials investigated herein, processing parameters need to be optimized as well as different glass frites should be tested.
Topics: Aluminum Oxide; Ceramics; Coated Materials, Biocompatible; Crystallization; Dental Porcelain; Dental Stress Analysis; Hot Temperature; Materials Testing; Particle Size; Pliability; Porosity; Surface Properties
PubMed: 26754431
DOI: 10.1016/j.dental.2015.12.009 -
Journal of Controlled Release :... Dec 2018Intranasal vaccination using dry powder vaccine formulation represents an attractive, non-invasive vaccination modality with better storage stability and added...
Intranasal vaccination using dry powder vaccine formulation represents an attractive, non-invasive vaccination modality with better storage stability and added protection at the mucosal surfaces. Herein we report that it is feasible to induce specific mucosal and systemic antibody responses by intranasal immunization with a dry powder vaccine adjuvanted with an insoluble aluminum salt. The dry powder vaccine was prepared by thin-film freeze-drying of a model antigen, ovalbumin, adsorbed on aluminum (oxy)hydroxide as an adjuvant. Special emphasis was placed on the characterization of the dry powder vaccine formulation that can be realistically used in humans by a nasal dry powder delivery device. The vaccine powder was found to have "passable" to "good" flow properties, and the vaccine was uniformly distributed in the dry powder. An in vitro nasal deposition study using nasal casts of adult humans showed that around 90% of the powder was deposited in the nasal cavity. Intranasal immunization of rats with the dry powder vaccine elicited a specific serum antibody response as well as specific IgA responses in the nose and lung secretions of the rats. This study demonstrates the generation of systemic and mucosal immune responses by intranasal immunization using a dry powder vaccine adjuvanted with an aluminum salt.
Topics: Adjuvants, Immunologic; Administration, Intranasal; Aluminum Hydroxide; Aluminum Oxide; Animals; Antigens; Brain; Bronchoalveolar Lavage Fluid; Female; Immunization; Immunoglobulin A; Immunoglobulin G; Nasal Lavage Fluid; Ovalbumin; Powders; Rats, Sprague-Dawley; Vaccines
PubMed: 30339906
DOI: 10.1016/j.jconrel.2018.10.020 -
Scientific Reports Aug 2022In the present work, different nanoparticles spinel ferrite series (MFeO, CoMFeO; M = Co, Mn, Ni, Mg, Cu, or Zn) have been obtained via sonochemical approach. Then,...
In the present work, different nanoparticles spinel ferrite series (MFeO, CoMFeO; M = Co, Mn, Ni, Mg, Cu, or Zn) have been obtained via sonochemical approach. Then, sol-gel method was employed to design core-shell magnetoelectric nanocomposites by coating these nanoparticles with BaTiO (BTO). The structure and morphology of the prepared samples were examined by X-ray powder diffraction (XRD), scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscope (HR-TEM), and zeta potential. XRD analysis showed the presence of spinel ferrite and BTO phases without any trace of a secondary phase. Both phases crystallized in the cubic structure. SEM micrographs illustrated an agglomeration of spherical grains with nonuniformly diphase orientation and different degrees of agglomeration. Moreover, HR-TEM revealed interplanar d-spacing planes that are in good agreement with those of the spinel ferrite phase and BTO phase. These techniques along with EDX analyses confirmed the successful formation of the desired nanocomposites. Zeta potential was also investigated. The biological influence of (MFeO, CoMFe) MNPs and core-shell (MFeO@BTO, CoMFe@BTO) magnetoelectric nanocomposites were examined by MTT and DAPI assays. Post 48 h of treatments, the anticancer activity of MNPs and MENCs was investigated on human colorectal carcinoma cells (HCT-116) against the cytocompatibility of normal non-cancerous cells (HEK-293). It was established that MNPs possess anti-colon cancer capability while MENCs exhibited a recovery effect due to the presence of a protective biocompatible BTO layer. RBCs hemolytic effect of NPs has ranged from non- to low-hemolytic effect. This effect that could be attributed to the surface charge from zeta potential, also the CoMnFe possesses the stable and lowest zeta potential in comparison with CoFeO and MnFeO also to the protective effect of shell. These findings open up wide prospects for biomedical applications of MNPs as anticancer and MENCs as promising drug nanocarriers.
Topics: Aluminum Oxide; Barium Compounds; Colorectal Neoplasms; Ferric Compounds; HEK293 Cells; Humans; Magnesium Oxide; Titanium
PubMed: 35986070
DOI: 10.1038/s41598-022-18306-5 -
Scientific Reports Jan 2024Aluminum oxide nanoparticle (AlNP), a ubiquitous neurotoxin highly enriched in air pollution, is often produced as an inevitable byproduct in the manufacturing of...
Aluminum oxide nanoparticle (AlNP), a ubiquitous neurotoxin highly enriched in air pollution, is often produced as an inevitable byproduct in the manufacturing of industrial products such as cosmetics and metal materials. Meanwhile, ALNP has emerged as a significant public health concern due to its potential association with neurological diseases. However, the studies about the neurotoxic effects of AlNP are limited, partially due to the lack of physiologically relevant human neurovascular unit with innate immunity (hNVUI). Here, we employed our AlNP-treated hNVUI model to investigate the underlying mechanism of AlNP-driven neurodegeneration. First, we validated the penetration of AlNP across a blood-brain barrier (BBB) compartment and found AlNP-derived endothelial cellular senescence through the p16 and p53/p21 pathways. Our study showed that BBB-penetrating AlNP promoted reactive astrocytes, which produced a significant level of reactive oxygen species (ROS). The astrocytic neurotoxic factors caused neuronal damage, including the synaptic impairment, the accumulation of phosphoric-tau proteins, and even neuronal death. Our study suggests that AlNP could be a potential environmental risk factor of neurological disorders mediated by neuroinflammation.
Topics: Humans; Air Pollution; Aluminum Oxide; Blood-Brain Barrier; Cell Death; Cellular Senescence; Neurotoxicity Syndromes
PubMed: 38185738
DOI: 10.1038/s41598-024-51206-4 -
Foot and Ankle Clinics Mar 2019Avascular necrosis tends to occur in the talus because of poor blood supply caused by the extended coverage to the articular cartilage on its surface. Treatment is... (Review)
Review
Avascular necrosis tends to occur in the talus because of poor blood supply caused by the extended coverage to the articular cartilage on its surface. Treatment is conservative in the earlier stage of this disease; however, surgical treatment is usually indicated in the advanced stage. Nonunion, leg length discrepancy, or hindfoot instability may occur in patients treated with ankle or tibio-talo-calcaneal fusion. Arthroplasty using a customized total talar prosthesis designed using the computed tomography image of contralateral talus has the potential advantages of weightbearing in the earlier postoperative phase, prevention of lower extremity discrepancy, and maintenance of joint function.
Topics: Aluminum Oxide; Ankle Joint; Arthrodesis; Arthroplasty, Replacement, Ankle; Humans; Joint Prosthesis; Osteonecrosis; Prosthesis Design; Talus
PubMed: 30685009
DOI: 10.1016/j.fcl.2018.10.004 -
International Journal of Environmental... Oct 2017O157:H7 is a well-recognized cause of human illness. Survival of O157:H7 in five purple soils from Sichuan Province was investigated. The dynamics of O157:H7 survival...
O157:H7 is a well-recognized cause of human illness. Survival of O157:H7 in five purple soils from Sichuan Province was investigated. The dynamics of O157:H7 survival in purple soils were described by the Weibull model. Results showed that this model is suitable to fit survival curves of O157:H7 in purple soils, with the calculated value (survival time needed to reach the detection limit of 100 CFU·g) ranging from 2.99 days to 26.36 days. The longest survival time of O157:H7 was observed in neutral purple soils (24.49 days), followed by alkalescent purple soil (18.62 days) and acid purple soil (3.48 days). The redundancy analysis (RDA) revealed that values were significantly enhanced by soil nutrition (total organic carbon (OC), total nitrogen (TN), available potassium (AK) and the ratio of humic acid to fulvic acid (Ha/Fa)), but were significantly suppressed by iron and aluminum oxide.
Topics: Aluminum Oxide; Benzopyrans; Carbon; China; Colony Count, Microbial; Escherichia coli O157; Humic Substances; Iron; Nitrogen; Potassium; Soil; Soil Microbiology
PubMed: 29057845
DOI: 10.3390/ijerph14101246 -
Journal of Cancer Research and... Apr 2023The aim of this study was to carried out the audit of radiotherapy centers practicing conformal radiotherapy techniques and demonstrate the suitability of this...
AIM
The aim of this study was to carried out the audit of radiotherapy centers practicing conformal radiotherapy techniques and demonstrate the suitability of this indigenous optically stimulated luminescence (OSL) disc dosimeters in beam quality audit and verification of patient-specific dosimetry in conventional and conformal treatments in radiotherapy.
MATERIALS AND METHODS
Dose audit in conventional and conformal (intensity-modulated radiotherapy and volumetric-modulated arc therapy) radiotherapy techniques was conducted using in-house developed Al2O3:C-based OSL disc dosimeter and commercially available Gafchromic EBT3 film in 6 MV (flat and unflat) photon and 6 and 15 MeV electron beams. OSL disc dosimeter and Gafchromic EBT3 film measured dose values were verified using the ionization chamber measurements.
RESULTS
Percentage variations of doses measured by OSL disc dosimeters and EBT3 Gafchromic film for conventional radiotherapy technique were in the range of 0.15%-4.6% and 0.40%-5.45%, respectively, with respect to the treatment planning system calculated dose values. For conformal radiotherapy techniques, the percentage variations of OSL disc and EBT3 film measured doses were in the range of 0.1%-4.9% and 0.3%-5.0%, respectively.
CONCLUSION
The results of this study supported by statistical evidence provided the confidence that indigenously developed Al2O3:C-based OSL disc dosimeters are suitable for dose audit in conventional and advanced radiotherapy techniques.
Topics: Humans; Radiation Dosimeters; Optically Stimulated Luminescence Dosimetry; Luminescence; Radiometry; Aluminum Oxide
PubMed: 37147959
DOI: 10.4103/jcrt.jcrt_753_21 -
Dental Materials Journal 2016This study evaluated cell viability, microhardness and flexural strength of two ceramic composites systems (ZA and AZ), pure alumina and zirconia. There were prepared...
This study evaluated cell viability, microhardness and flexural strength of two ceramic composites systems (ZA and AZ), pure alumina and zirconia. There were prepared homogeneous mixtures of 78wt%Al2O3+20wt%3Y-TZP+2wt%Al2O3w (AZ) and 80wt%3YTZP+18wt%Al2O3+2wt%Al2O3w (ZA), as well as 3Y-TZP (Z), pure Al2O3 (A) and commercial monolithic 3Y-TZP (Zc). Also mouse fibroblast cells 3T3-L1 and a MTT test was carried out at 24, 48 and 72 h. The surfaces were observed with SEM and the microhardness and three-point flexural strength values were estimated. The absolute microhardness values were: A>AZ>Z>Zc>ZA. Flexural strength of Zc, Z, and ZA were around double than AZ and A. All groups showed high biocompatibility trough cell viability values at 24, 48 and 72 h. Factors like grain shape, grain size and homogeneous or heterogeneous grain distributions may play an important role in physical, mechanical and biological properties of the ceramic composites.
Topics: Aluminum Oxide; Animals; Ceramics; Fibroblasts; Materials Testing; Mice; Zirconium
PubMed: 27251994
DOI: 10.4012/dmj.2015-028 -
Scientific Reports Feb 2022Outdoor breathing trials with simulated avalanche snow are fundamental for the research of the gas exchange under avalanche snow, which supports the development of the... (Randomized Controlled Trial)
Randomized Controlled Trial
Outdoor breathing trials with simulated avalanche snow are fundamental for the research of the gas exchange under avalanche snow, which supports the development of the international resuscitation guidelines. However, these studies have to face numerous problems, including unstable weather and variable snow properties. This pilot study examines a mineral material perlite as a potential snow model for studies of ventilation and gas exchange parameters. Thirteen male subjects underwent three breathing phases-into snow, wet perlite and dry perlite. The resulting trends of gas exchange parameters in all tested materials were similar and when there was a significant difference observed, the trends in the parameters for high density snow used in the study lay in between the trends in dry and wet perlite. These findings, together with its stability and accessibility year-round, make perlite a potential avalanche snow model material. Perlite seems suitable especially for simulation and preparation of breathing trials assessing gas exchange under avalanche snow, and potentially for testing of new avalanche safety equipment before their validation in real snow.The study was registered in ClinicalTrials.gov on January 22, 2018; the registration number is NCT03413878.
Topics: Adult; Aluminum Oxide; Avalanches; Cardiopulmonary Resuscitation; Cross-Over Studies; Czech Republic; Double-Blind Method; Humans; Male; Models, Theoretical; Pilot Projects; Prospective Studies; Pulmonary Gas Exchange; Respiration; Silicon Dioxide; Simulation Training; Snow; Young Adult
PubMed: 35136116
DOI: 10.1038/s41598-022-06015-y -
Orthopaedics & Traumatology, Surgery &... Feb 2021Hip revision surgery for fractured ceramic components may represent the worst-case wear scenario due to the high risks of recurrent dislocations, instability, and third...
BACKGROUND
Hip revision surgery for fractured ceramic components may represent the worst-case wear scenario due to the high risks of recurrent dislocations, instability, and third body wear. The ideal bearing choice for the new prosthetic articulation is still subject of debate, while alumina matrix composite (AMC) articulations offer theoretical superior performances; the present work was designed to test the wear behaviour of ceramic on ceramic articulations (liner and head) in a worst-case scenario by adding ceramic third-body particles to the test lubricant with combined walking and subluxation cycles in a hip joint simulator. Therefore, we performed an in vitro study aiming to assess how does AMC articulation perform with 1) third-body particles added to the test environment and 2) under subluxation stresses.
HYPOTHESIS
We hypothesised that AMC articulations offer superior performances in such worst conditions.
MATERIALS AND METHODS
A hip simulator test was designed to analyse how AMC articulation performs with third-body particles added to the test environment and under subluxation stresses. Two different load patterns including level walking and subluxation of the ceramic liner were applied. The test fluid lubricant was contaminated by adding coarse ceramic particles during the first 2 million cycles and fine ceramic particles from 2 to 4 million cycles. Group 1 consisted of an alumina matrix composite articulation (liner and head); group 2 consisted of an alumina liner and an alumina matrix composite head. A control group consisting of an alumina ceramic liner articulated against an alumina matrix composite head was provided and only axially loaded. The liners of groups 1 and 2 were tested at an in vivo angle of 45° in the medial lateral plane (inclinationangle), which corresponds to an angle L=30° relative to the ISO standard fixated position used for in vitro testing. All mass measurements were performed using a high precision balance (Sartorius BP211D). During each examination, images on dedicated location of the bearing surfaces were taken using a digital microscope.
RESULTS
Mean cumulative wear of 0.09mg per million cycles between 2 and 4 million cycles was detected in group 2, and this value was significantly lower (p=0.016) in comparison with the average value in group 1 (0.21mg per million cycle). This result can be explained in light of a possible transformation phase of zirconia in AMC liners, probably due to excessive stress during subluxation cycles. However, wear levels observed are close to the gravimetric measurement detection limit of the Sartorious Balance (about 0.1-0.2mg); therefore, wear can be considered negligible in all groups.
CONCLUSION
Our results confirm that AMC couplings perform very well even in the worst-case wear scenario. Since AMC articulations revealed 25% lower cumulative wear respect to AMC on cross linked polyethylene in same simulator setup, AMC articulations should be considered the bearing of choice in revision surgery in light of the high risk of recurrent dislocations, instability, and third body wear.
LEVEL OF EVIDENCE
III, prospective case-control study, in vitro.
Topics: Aluminum Oxide; Arthroplasty, Replacement, Hip; Case-Control Studies; Ceramics; Hip Prosthesis; Humans; Materials Testing; Prospective Studies; Prosthesis Design; Prosthesis Failure
PubMed: 32684432
DOI: 10.1016/j.otsr.2020.05.003