These features introduce surface roughness that depends on the degree of hydrogenation and reaches its maximum levels at intermediate levels of H coverage. (c) 2010 American Institute Selleckchem RG-7112 of Physics. [doi: 10.1063/1.3514158]“
“Objective. The aim of
this study was to evaluate cyclic fatigue resistance of used and new RaCe rotary nickel-titanium instruments.
Study design. Forty RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) instruments of sizes 30/.06, 30/.02, 25/.04, and 25/.02 were selected and divided into 2 groups: group A = 20 new instruments; group B = 20 used instruments. In group B, each instrument was used for shaping 5 curved molar root canals. Cyclic fatigue testing of new and used instruments was performed using a device that allowed the instruments to rotate freely inside a stainless steel artificial canal. Data
NU7441 mouse were analyzed using t test to determine any statistical significance between used and new instruments of the same file size.
Results. For all sizes, new instruments were more resistant to failure then the used ones (P < .05). A reduction in lifespan was observed ranging from 18% (30/.06) to 51% (25/.02).
Conclusion. The results showed that clinical use significantly reduced cyclic fatigue resistance of RaCe rotary instruments compared with new ones. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: e131-e134)”
“Monomethoxy poly(ethylene glycol) acrylate (MPEGA) was synthesized through the esterification reaction of acrylic acid and methoxy poly(ethylene glycol)s (MPEGs) of different molecular weights. Then, MPEGA was copolymerized with methyl methacrylate, butyl acrylate, and beta-carboxyethyl
acrylate neutralized with potassium hydroxide via conventional solution polymerization. In this way, a single-ion conductive polymer-electrolyte-based antistatic agent (PEAA), in which potassium (K) ions were used as charge JAK inhibitor carriers, was obtained. The molecular structure, coordination effects between ether oxygen (EO) groups and K cations, ionic conductivity, and crystallization ability of the copolymer were characterized with Fourier transform infrared, conductivity measurements, polarizing optical microscopy, and differential scanning calorimetry, respectively. The crystallinity of the synthesized PEAA apparently decreased with the molecular weight of MPEG and the EO/K molar ratio decreasing, and this led to a corresponding enhancement of the conductivity. The dependence of the conductivity of the copolymer on temperature could be divided into different linear parts, and each was in good agreement with the Arrhenius equation.