Effects of 35% Carbamide Peroxide Gel on Surface Roughness and Hardness of Composite Resins

Objective: Bleaching agents may not be safe for dental materials. The purpose of this invitro study was to evaluate the effects of Opalescent Quick "in-office bleaching gel" containing 35% carbamide peroxide on the surface roughness and hardness of microfilled(Heliomolar) and hybride (Spectrum TPH) composite resins.Materials and Methods: Twenty specimens of Spectrum TPH composite resins and twenty Heliomolar composite resins were fabricated using a metallic ring (6.5 mm diameter and 2.5 mm thickness) and light cured, then their surfaces were polished. Specimens of each composite resin were divided into two equal groups. Ten specimens of each type of composite were stored in water at 37°C as the control groups and 35% carbamide peroxide gel (Opalescence Quick) as the other group for 30 minutes a week for 3 weeks. Then the specimens were subject to roughness and hardness tests.Results: This study revealed that using 35% carbamide peroxide bleaching gels had no significant effect on the surface roughness of Spectrum TPH "hybrid" and Heliomolar "microfilled" composite resins. The surface hardness of Spectrum TPH composite treated with the subject gel significantly increased compared to heliomolar, which had no significant change after treatment with this bleaching gel.Conclusion: If tooth color matching of the composite had been satisfactory after office bleaching with 35% carbamide peroxide gel, this material would have been acceptable because it has no adverse effect on Heliomolar and Spectrum TPH composite resins

Brentano’s lectures on positivism (1893-1894) and his relationship to Ernst Mach

This paper is mainly about Brentano’s commentaries on Ernst Mach in his lectures “Contemporary philosophical questions” which he held one year before he left Austria. I will first identify the main sources of Brentano’s interests in Comte’s and J. S. Mill’s positivism during his Würzburg period. The second section provides a short overview of Brentano’s 1893-1894 lectures and his criticism of Comte, Kirchhoff, and Mill. The next sections bear on Brentano’s criticism of Mach’s monism and Brentano’s argument against the reduction of the mental based on his theory of intentionality. The last section is about Brentano’s proposal to replace the identity relation in Mach’s theory of elements by that of intentional correlation. I conclude with a remark on the history of philosophy in Austria

Developing and scaling up fast-dissolving electrospun formulations based on poly(vinylpyrrolidone) and ketoprofen

Poly(vinyl pyrrolidone) (PVP) electrospun fibers loaded with ketoprofen were fabricated in this work as potential fast dissolving drug delivery systems (DDSs) for oral delivery. By changing the processing parameters and collector geometry it was possible to increase the throughput rate from 1 to 20 mL/h. The fibers all took the shape of cylinders and had smooth surfaces. They comprise amorphous solid dispersions of drug-in-polymer, with very high drug encapsulation efficiencies (100%). With a low drug loading (9.09% w/w) the electrospun materials could disintegrate quickly and accelerate the dissolution profile of ketoprofen under non-sink conditions representative of the oral cavity. However, at higher loadings (23.08% w/w), this benefit is no longer realized, indicating that there is a maximum drug loading above which the dissolution-enhancing properties of the amorphous form and the hydrophilic PVP carrier cease to be effective. After storage under ambient conditions (19–21 °C, relative humidity 30–40%) for 4 weeks, the formulations remained amorphous, with no significant changes in their drug release properties. Very similar behaviour in terms of drug release and storage stability was seen regardless of the throughput rate used for fiber fabrication, showing the potential to rapidly produce large amounts of high-performing material

Clubroot (Plasmodiophora brassicae Woronin): an agricultural and biological challenge worldwide

Clubroot disease and the causal microbe Plasmodiophora brassicae offer abundant challenges to agriculturists and biological scientists. This microbe is well fitted for the environments which it inhabits. Plasmodiophora brassicae exists in soil as microscopic well protected resting spores and then grows actively and reproduces while shielded inside the roots of host plants. The pathogen is active outside the host for only short periods. Consequently, scientific studies are made challenging by the biological context of the host and pathogen and the technology required to investigate and understand that relationship. Controlling clubroot disease is a challenge for farmers, crop consultants and plant pathology practitioners because of the limited options which are available. Full symptom expression happens solely in members of the Brassicaceae family. Currently, only a few genes expressing strong resistance to P. brassicae are known and readily available. Agrochemical control is similarly limited by difficulties in molecule formulation which combines efficacy with environmental acceptability. Manipulation of husbandry encouraging improvements in soil structure, texture, nutrient composition and moisture content can reduce populations of P. brassicae. Integrating such strategies with rotation and crop management will reduce but not eliminate this disease. There are indications that forms of biological competition may be mobilised as additions to integrated control strategies. The aim of this review is to chart key themes in the development of scientific biological understanding of this host-pathogen relationship by offering signposts to grapple with clubroot disease which devastates crops and their profitability. Particular attention is given to the link between soil and nutrient chemistry and activity of this microbe

The hot and cold interstellar matter of early type galaxies and their radio emission

Over the last few years, the knowledge of the interstellar matter (ISM) of early type galaxies has increased dramatically. Many early type galaxies are now known to have ISM in three different phases: cold (neutral hydrogen (HI), dust and molecular material), warm (ionized) and hot (S-ray emitting) gas. Early type galaxies have smaller masses of cold ISM (10 to the 7th power - 10 to the 8th power solar mass; Jura et al. 1987) than later type spiral galaxies, while they have far more hot gas (10 to the 9th power - 10 to the tenth power solar mass; Forman et al. 1985, Canizares et al. 1987). In order to understand the relationship between the different phases of the ISM and the role of the ISM in fueling radio continuum sources and star formation, researchers compared observational data from a wide range of wavelengths

Ascorbic acid is a regulator of the intracellular cAMP concentration: Old molecule, new functions?

AbstractRecently, using an animal model of Charcot-Marie-Tooth human disorder, we showed that ascorbic acid (AA) represses PMP22 gene expression by acting on intracellular cAMP concentrations. In this work, we present kinetics data on the inhibitory effect of AA upon adenylate cyclase activity. The data show that this molecule acts as a competitive inhibitor of the enzyme, a finding that opens new pharmacological avenues

Theranostics for MRI‐guided therapy: Recent developments

Recent advances in bioimaging, biochemistry, and bioinformatics have facilitated the development of personalized and precision medicine. Theranostics, combining imaging modalities and therapeutic agents, have garnered a lot of attention in this context, owing to their potential to monitor and control treatment for individual patients. A promising strategy to achieve this goal involves the development of therapy guided by magnetic resonance imaging (MRI). MRI has a high degree of soft tissue contrast, low invasiveness, high depth of penetration and good spatial resolution. MRI-guided therapy could thus allow precise and time-resolved assessment of disease conditions and therapeutic progression. This article will give a brief introduction to the principles of MRI, and describe recently developed strategies to produce MRI-guided therapies. A number of theranostics based on T1, T2, or chemical exchange saturation transfer (CEST) MRI have been explored to track the route of drug carriers in vivo and image diseased tissue so as to enhance bioavailability, overcome complex delivery barriers, and assess therapeutic responses. In addition, the integration of thermal therapy and MRI imaging offers a strategy to noninvasively identify target areas, plan treatment, and provide real-time assessment of the efficacy of tumor ablation. We also discuss advances in intelligent nanoparticles combining small molecule drugs, thermal treatment and multimodal imaging, arguing that these multifunctional agents can further improve therapeutic outcomes

The role of lattice parameter in water adsorption and wetting of a solid surface

Reducing the lattice parameter of a Sn–metal surface alloy below the O–O separation of ice disrupts the flat wetting layer, causing the first layer to buckle and instead form ice clusters.</p