Hudsonholmberg7360
To develop an aesthetic resin composite using a nitrogen-doped titanium dioxide (NTiO
) filler that possesses antimicrobial properties against cariogenic bacteria.
N-TiO
powder was manufactured by calcining commercial TiO
with urea. Free radical release from the N-TiO
powder under visible light irradiation was analysed using UV-Vis spectrophotometry. The N-TiO
powder was incorporated into a dental resin and the photocatalytic activity assessed using a dye under both visible light and dark conditions. Using XTT assay to measure the cellular metabolic activity, the antibacterial properties of the N-TiO
/resin composite discs were tested using Streptococcus mutans.
Doping nitrogen of TiO
resulted in a band gap shift towards the visible light spectrum, which enabled the powder to release reactive oxygen species when exposed to visible light. When incorporated into a dental resin, the N-TiO
/resin composite still demonstrated sustained release of reactive oxygen species, maintaining its photocatalytic activity and showing an antibacterial effect towards Streptococcus mutans under visible light conditions.
N-TiO
filled resin composite shows great promise as a potential aesthetic resin based adhesive for orthodontic bonding.
N-TiO2 filled resin composite shows great promise as a potential aesthetic resin based adhesive for orthodontic bonding.
To fabricate and characterise a novel chairside CAD/CAM composite dental materials. selleck compound These composites have a nacre-like anisotropic microstructure, consisting of highly aligned ceramic scaffolds infiltrated with polymer.
Bi-directional freeze casting of alumina ceramic suspension was used to fabricate highly aligned ceramic scaffolds that were subsequently uniaxially pressed to control the ceramic volume fraction and then infiltrated with UDMA/TEGDMA polymer. The produced composites were subjected to mechanical testing, namely three-point bending, hardness and fracture toughness tests.
Novel biomimetic ceramic/polymer composites (BCPCs) were fabricated with nacre-like brick and mortar anisotropic microstructure. The mechanical properties were dependent on the ceramic volume fraction. The 70vol% BCPC had sufficient flexural strength (135.08-145.77MPa), stiffness (57.75-61.22GPa) and hardness (3.07-3.36GPa) and showed remarkable fracture resistance with K
value of (2.54MPam
).
Novel biomimetic ceramic/polymer composites show great potential as the next generation of CAD/CAM dental materials, as they closely resemble the combined mechanical properties of dentine and enamel.
Novel biomimetic ceramic/polymer composites show great potential as the next generation of CAD/CAM dental materials, as they closely resemble the combined mechanical properties of dentine and enamel.
The chemical affinity between 10-methacryloyloxydecyl dihydrogen phosphate (MDP) and hydroxyapatite (HAp) is an important factor in the enamel bonding provided by MDP-based self-etch (SE) adhesives, besides microinterlocking mechanisms. This study aimed to investigate how phosphoric acid pre-etching affects MDP-Ca salt formation in the application of MDP-based SE adhesives.
Single Bond Universal (SBU), All Bond Universal (ABU), Clearfil Universal Bond Quick (CBQ), and a MDP-based all-in-one adhesive (EXP) were used in both SE and etch-and-rinse (ER) modes, along with Clearfil SE Bond and untreated enamel (UE) as controls. The MDP-Ca salts produced with or without etching were examined by nuclear magnetic resonance, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. Zeta potential, contact angle, and scanning electron microscopy measurements were employed to elucidate the mechanism behind the changes in MDP/HAp chemical affinity upon pre-etching.
The percentage of MDP-Ca salt in EXP_ER (73.13%) was higher than that in EXP_SE (43.27%). Characteristic CH
(1130, 1441, 2853, and 2909cm
), CC (1641cm
), and CO (1718cm
) bands were observed in the Raman spectra of EXP_ER. Pre-etching increased the negative zeta potential of the enamel surface compared to that of UE (P<0.001). The contact angles of MDP-based adhesives applied to pre-etched enamel were significantly lower than those of the self-etched surface (P<0.05).
The increased MDP-Ca salt formation is a significant advantage of phosphoric acid pre-etching, improving the MDP/HAp chemical affinity in addition to increasing surface wettability.
The increased MDP-Ca salt formation is a significant advantage of phosphoric acid pre-etching, improving the MDP/HAp chemical affinity in addition to increasing surface wettability.
Upon initial proximal wall construction, the favorable C-factor of class-II cavities may become unfavorable. This study investigated the application method on bulk-fill resin composite polymerization shrinkage.
Occluso-proximal class-II cavities were prepared in 40 molars and bonded with a self-etch adhesive (Adhese Universal). The study groups varied according to the resin composite application group-1 bulk application, Tetric EvoCeram Bulk Fill (TBF); group-2 proximal wall construction (TBF) and occlusal cavity filling (TBF); group-3 thin flowable liner layer, Tetric EvoFlow Bulk Fill (TEF) and bulk filling (TBF); group-4 flowable liner (TEF), proximal wall (TBF), occlusal cavity (TBF); and group-5 bulk application, SDR (3mm) and capping layer (TBF, 1mm). Each resin composite increment was scanned twice using micro-CT (uncured, cured 40s) at a resolution of 16µm. Shrinkage vectors and volumetric polymerization shrinkage were evaluated and statistically analyzed (one-way ANOVA). SEM images were used to investigate the tooth-restoration interface.
Shrinkage vectors differed significantly among the groups and were greatest in gp5-fl/SDR (47.6µm), followed by gp1-TBF (23.8µm) and least in gp5-fl/SDR+TBF (11.1µm). Volumetric shrinkage varied significantly with the use of SDR (gp5-fl/SDR 2.6%) and TEF (gp4-fl/TEF 2.5%) to TBF (gp4-fl/TEF+wl/TBF 0.6%) in the incremental application.
Building a proximal resin composite wall yielded smaller shrinkage vectors than the bulk application. Applying a thin flowable liner decreased the shrinkage vectors, even more when building a proximal wall. A thin flowable liner is recommended when building a proximal resin composite wall.
Building a proximal resin composite wall yielded smaller shrinkage vectors than the bulk application. Applying a thin flowable liner decreased the shrinkage vectors, even more when building a proximal wall. A thin flowable liner is recommended when building a proximal resin composite wall.In this study, three Co/N-C catalysts were prepared by pyrolysis of bimetallic zeolitic imidazole frameworks with different Co/Zn ratio, and the critical active Co species in peroxymonosulfate (PMS) activation was investigated. The three catalysts had distinct cobalt species but similar N configuration and graphitization degree. The Co species were distributed as single atoms (Co SAs) at a Co/Zn molar ratio of 18, while Co nanoclusters (Co NCs) and Co nanoparticles (NPs) would be formed with further increase in Co content. The degradation efficiency of BPA did not show correlation with the increasing of Co content in catalyst. Based on the catalytic performance comparison and reactive species detection, Co SAs was identified as active sites, which could interact with PMS to generate 1O2 via path of PMS→HOO*→O*→1O2. However, the role of NCs and NPs in directly activating PMS was negligible. In addition, the increase of Co content in Co/N-C catalyst would result in mass cobalt leaching, which enhanced the BPA degradation via homogeneous catalytic reactions with CoIV as reactive species. It is an effective way to design the Co/N-C catalyst with high catalytic activity and stability via regulating the formation of Co SAs.The presence of organic micropollutant (OMP) in groundwater threatens drinking water quality and public health. Rapid sand filter (RSF) rely on biofilms with nitrifying and methanotrophic bacteria to remove ammonia and methane during drinking water production. Previous research observed the partial removal of OMPs with active nitrification and methane oxidation due to co-metabolic conversion of OMPs. However, the contribution of indigenous nitrifying and methanotrophic communities from RSF has yet to be fully explored. Accordingly, experiments were carried out with biofilm-covered sand collected from field-scale RSF, to assess the removal of nine OMPs by nitrifying and methanotrophic bacteria. Results indicated that stimulating nitrification resulted in significantly more removal of caffeine, 2,4-dichlorophenoxyacetic acid and bentazone. link2 Stimulating methanotrophic conditions enhanced the removal of caffeine, benzotriazole, 2,4-dichlorophenoxyacetic acid and bentazone. Microbial community analysis based on 16 S rRNA gene sequencing revealed Nitrosomonas and Nitrospira are the dominant genus in the community under nitrifying conditions. The three genera Methylobacter, Methylomonas and Methylotenera were enriched under methanotrophic conditions. This study highlights that nitrifying and methanotrophic bacteria play important roles during OMP removal in field RSF. Furthermore, results suggest that bioaugmentation with an enriched nitrifying and methanotrophic culture is a promising approach to improve OMP removal in RSF.Purification and recovery of strategic W/Mo/Re from wastewaters face a dual concern for resource recovery and environmental pollution. In this work, a novel manganese ferrite nanoparticles (MFO-NPs) was prepared from the low-grade manganese ore via pyrometallurgical transformation followed by nano sanding. The effects of pH, initial concentration, and reaction time on adsorption behaviors of simplex and mixed W/Mo/Re by MFO-NPs were investigated. Single anion adsorption indicated that molybdate and tungstate adsorption were consistent with the Langmuir isotherm model with the highest adsorption capacities of 41.985 mg/g and 85.61 mg/g, respectively; whereas rhenate was not adsorped. Selective separation indicated that W was firstly separated by MFO-NPs adsorption at pH of 5. After that, Mo was further adsorped by MFO-NPs at pH of 2-4 while Re was kept in the raffinate. The possible selective adsorption mechanism was based on the difference of electrostatic adsorption, polar adsorption, and complexing reaction between MFO-NPs and W/Mo/Re anions, which had various ionic forms under different pH values. Compared with the MFO-NPs prepared by wet chemistry methods, the novel MFO-NPs proposed in this work not only showed satisfactory adsorption capacity but had huge potential for the selective separation of W, Mo, and Re.Bisphenols and benzophenone UV-filters are hazardous, high production volume chemicals. There is concern that these contaminants could leach into the environment or be recycled into new products during waste management. To investigate this, nine bisphenols and five benzophenones were quantified in Norwegian e-waste and car fluff. To understand their leachability, equilibrium passive sampling methodology, using polyoxymethylene (POM), was calibrated for these substances, many of which for the first time. link3 This method can differentiate freely dissolved substances in the aqueous phase from those sorbed to suspended colloids and microplastics in the leachate water. Equilibrium POM partitioning was reached within 14 days of shaking; all bisphenols and benzophenone UV-filters exhibited linear isotherms (R2 ranged from 0.83 to 1.0), when deriving POM-water partition coefficients (KPOM). Bisphenol A and bisphenol F displayed the highest concentrations, with maximum levels of 246,000 and 42,400 ng g-1, respectively. Logarithms of waste-water partition coefficients (log Kwaste) ranged from 1.
