The solid photoinitiator Lucirin TPO was encapsulated within a polymer shell by using the miniemulsion process. A solution of Lucirin TPO in methyl methacrylate (MMA) or butyl acrylate (BA)/MMA ...mixture was miniemulsified in water followed by a polymerization process in which phase separation of the Lucirin TPO and the formed polymer led to amorphously solidified Lucirin TPO nanoparticles encapsulated by polymer. These nanocapsules were freeze-dried and could be redispersed in acidic monomers, which are applied in polymeric dental adhesives. It is shown by ^sup 1^H nuclear magnetic resonance spectroscopy that the shell separates the Lucirin TPO, which is sensitive to degradation in acidic media, from an ambient acidic monomer phase and protects it from fast decomposition. Investigations of the release kinetics of Lucirin TPO from the nanocapsules reveal that the kinetics are strongly dependent on the composition of the surrounding continuous phase.PUBLICATION ABSTRACT
Surface functionalization of radiopaque Ta 2O 5/SiO 2 Schulz, Heiko; Pratsinis, Sotiris E.; Rüegger, Heinz ...
Colloids and surfaces. A, Physicochemical and engineering aspects,
2008, Letnik:
315, Številka:
1
Journal Article
Recenzirano
Mixed Ta
2O
5/SiO
2 nanoparticles are attractive for their high radiopacity as transparent dental fillers and even for bone replacement. The effect of Ta
2O
5 content on surface acidity of flame-made ...Ta
2O
5/SiO
2 particles was studied by NH
3 temperature-programmed desorption (TPD). Emphasis was placed on the influence of particle composition on surface functionalization by a common surfactant, γ-methacryloxypropyltrimethoxysilane (MPS). Such surface modified particles were analyzed by thermogravimetric analysis,
13C- and
29Si-NMR and FT-IR spectroscopy. Compared to pure silica, Ta
2O
5/SiO
2 particles exhibited significantly higher surface acidity, thereby facilitating functionalization of their surface hydroxyl groups without a catalyst (e.g.
n-propylamine, PA). The surface modifier structure was only slightly influenced by the Ta
2O
5 presence compared to pure SiO
2. The long term hydrolytic stability of such surface modified Ta
2O
5/SiO
2 particles was comparable to pure silica up to 80 days at 22
°C indicating stable bonding between particle surface and modifier.
Radiopaque dental adhesive (DA) of low viscosity were made by forming stable suspensions of weakly agglomerated Ta2O5/SiO2 nanoparticles with primary particle size of about 10nm. The particles were ...prepared by one-step flame-spray pyrolysis. Particles were functionalized with γ-methacryloxypropyltrimethoxysilane (MPS) and dispersed in a methacrylic monomer matrix by centrifugal mixing and ultrasonication. Particle size distributions were analyzed by X-ray disc centrifugation of suspensions and TEM analysis of cured sample composites, while average primary particle size was obtained by N2 adsorption and X-ray diffraction. The dispersion method affected the aggregate size distribution of both untreated and surface functionalized particles in these suspensions. The influence of particle content on suspension viscosity, aggregate size distribution and that of Ta2O5 content on radiopacity was investigated. The shear bond strength of such radiopaque particle-containing adhesives on enamel and dentin was comparable to that of the particle-free reference adhesive. Flame-made Ta2O5/SiO2 nanoparticles can be introduced readily into dental adhesives as they form quite stable suspensions. Viscosity stayed low even after adding radiopaque particles up to 20wt.%. The resulting composites had radiopacity comparable to that of enamel facilitating their distinction from marginal gaps. Bond strength was not significantly influenced by the presence of particles in the adhesive.
Abstract Objectives Radiopaque dental adhesive (DA) of low viscosity were made by forming stable suspensions of weakly agglomerated Ta2 O5 /SiO2 nanoparticles with primary particle size of about 10 ...nm. Methods The particles were prepared by one-step flame-spray pyrolysis. Particles were functionalized with γ-methacryloxypropyltrimethoxysilane (MPS) and dispersed in a methacrylic monomer matrix by centrifugal mixing and ultrasonication. Particle size distributions were analyzed by X-ray disc centrifugation of suspensions and TEM analysis of cured sample composites, while average primary particle size was obtained by N2 adsorption and X-ray diffraction. Results The dispersion method affected the aggregate size distribution of both untreated and surface functionalized particles in these suspensions. The influence of particle content on suspension viscosity, aggregate size distribution and that of Ta2 O5 content on radiopacity was investigated. The shear bond strength of such radiopaque particle-containing adhesives on enamel and dentin was comparable to that of the particle-free reference adhesive. Conclusions Flame-made Ta2 O5 /SiO2 nanoparticles can be introduced readily into dental adhesives as they form quite stable suspensions. Viscosity stayed low even after adding radiopaque particles up to 20 wt.%. The resulting composites had radiopacity comparable to that of enamel facilitating their distinction from marginal gaps. Bond strength was not significantly influenced by the presence of particles in the adhesive.
Radiopaque dental adhesive (DA) of low viscosity were made by forming stable suspensions of weakly agglomerated Ta
2O
5/SiO
2 nanoparticles with primary particle size of about 10
nm.
The particles ...were prepared by one-step flame-spray pyrolysis. Particles were functionalized with γ-methacryloxypropyltrimethoxysilane (MPS) and dispersed in a methacrylic monomer matrix by centrifugal mixing and ultrasonication. Particle size distributions were analyzed by X-ray disc centrifugation of suspensions and TEM analysis of cured sample composites, while average primary particle size was obtained by N
2 adsorption and X-ray diffraction.
The dispersion method affected the aggregate size distribution of both untreated and surface functionalized particles in these suspensions. The influence of particle content on suspension viscosity, aggregate size distribution and that of Ta
2O
5 content on radiopacity was investigated. The shear bond strength of such radiopaque particle-containing adhesives on enamel and dentin was comparable to that of the particle-free reference adhesive.
Flame-made Ta
2O
5/SiO
2 nanoparticles can be introduced readily into dental adhesives as they form quite stable suspensions. Viscosity stayed low even after adding radiopaque particles up to 20
wt.%. The resulting composites had radiopacity comparable to that of enamel facilitating their distinction from marginal gaps. Bond strength was not significantly influenced by the presence of particles in the adhesive.
Investigation of diseases of the bile duct system and identification of potential therapeutic targets are hampered by the lack of tractable in vitro systems to model cholangiocyte biology. Here, we ...show a step-wise method for the differentiation of murine Lgr5+ liver stem cells (organoids) into cholangiocyte-like cells (CLCs) using a combination of growth factors and extracellular matrix components. Organoid-derived CLCs display key properties of primary cholangiocytes, such as expressing cholangiocyte markers, forming primary cilia, transporting small molecules and responding to farnesoid X receptor agonist. Integration of organoid-derived cholangiocytes with collagen-coated polyethersulfone hollow fiber membranes yielded bioengineered bile ducts that morphologically resembled native bile ducts and possessed polarized bile acid transport activity. As such, we present a novel in vitro model for studying and therapeutically modulating cholangiocyte function.
This multi-institutional study investigates whether computational verification of fluence-modulated treatment plans using independent software with its own Strahlerkopfmodel is an appropriate method ...for patient-related quality assurance (PRQA) in the context of various combinations of linear accelerators (linacs), treatment techniques and treatment planning systems (TPS).
The PRQA-software's (Mobius3D) recalculations of 9 institutions’ treatment plans were analyzed for a horseshoe-shaped planning target volume (PTV) inside a phantom. The recomputed dose distributions were compared to a) the dose distributions as calculated by all TPS's and b) the measured dose distributions, which were acquired using the same independent measuring system for all institutions. Furthermore, dose volume histograms were examined. The penumbra deviations and mean gamma values were quantified using Verisoft (PTW). Additionally, workflow requirements for computational verification were discussed.
Mobius3D is compatible with all examined TPSs, treatment techniques and linacs. The mean PTV dose differences (Mobius3D-TPS, <3.0%) and 3D gamma passing rates (>95.0%) led to a positive plan acceptance result in all cases. These results are similar to the outcome of the dosimetric measurements with one exception. The mean gamma values (<0.5) show a good agreement between Mobius3D and the TPS dose distributions.
Using Mobius3D was proven to be an appropriate computational PRQA method for the tested combinations of linacs, treatment techniques and TPS's. The clinical use of Mobius3D has to be complemented with regular dosimetric measurements and thorough linac and TPS QA. Mobius3D's computational verification reduced measurement effort and personnel needs in comparison to dosimetric verifications.
We evaluate the feasibility of the implementation of two quantum repeater protocols with an existing experimental platform based on a \(^{40}\)Ca\(^+\)-ion in a segmented micro trap, and a third one ...that requires small changes to the platform. A fiber cavity serves as an ion-light interface. Its small mode volume allows for a large coupling strength of \(g_c = 2 \pi 20\) MHz despite comparatively large losses \(\kappa = 2 \pi 36.6\) MHz. With a fiber diameter of 125 mu m, the cavity is integrated into the microstructured ion trap, which in turn is used to transport single ions in and out of the interaction zone in the fiber cavity. We evaluate the entanglement generation rate for a given fidelity using parameters from the experimental setup. The DLCZ protocol (Duan et al, Nature, 2001, 414, 413-418) and the hybrid protocol (van Loock et al, Phys. Rev. Lett., 2006, 96, 240501) outperform the EPR protocol (Sanguard et al, New J. Phys., 2013, 15, 085004). We calculate rates of more than than 35 s\(^{-1}\) for non-local Bell state fidelities larger than 0.9 with the existing platform. We identify parameters which mainly limit the attainable rates, and conclude that entanglement generation rates of 740 s\(^{-1}\) at fidelities of 0.9 are within reach with current technology.
