Class I Gap-formation in Highly-viscous Glass-ionomer Restorations: Delayed vs Immediate Polishing

This in vitro study evaluated the effects of delayed versus immediate polishing to permit maturation of interfacial gap-formation around highly viscous conventional glass-ionomer cement (HV-GIC) in Class I restorations, together with determining the associated mechanical properties. Cavity preparations were made on the occlusal surfaces of premolars. Three HV-GICs (Fuji IX GP, GlasIonomer FX-II and Ketac Molar) and one conventional glass-ionomer cement (C-GIC, Fuji II, as a control) were studied, with specimen subgroups (n=10) for each property measured. After polishing, either immediately (six minutes) after setting or after 24 hours storage, the restored teeth were sectioned in a mesiodistal direction through the center of the model Class I restorations. The presence or absence of interfacial-gaps was measured at 1000× magnification at 14 points (each 0.5-mm apart) along the cavity restoration interface (n=10; total points measured per group = 140). Marginal gaps were similarly measured in Teflon molds as swelling data, together with shear-bond-strength to enamel and dentin, flexural strength and moduli. For three HV-GICs and one C-GIC, significant differences (p<0.05) in gap-incidence were observed between polishing immediately and after one-day storage. In the former case, 80–100 gaps were found. In the latter case, only 9–21 gaps were observed. For all materials, their shear-bond-strengths, flexural strength and moduli increased significantly after 24-hour storage.</p

Class I Gap-formation in Highly-viscous Glass-ionomer Restorations: Delayed vs Immediate Polishing

This in vitro study evaluated the effects of delayed versus immediate polishing to permit maturation of interfacial gap-formation around highly viscous conventional glass-ionomer cement (HV-GIC) in Class I restorations, together with determining the associated mechanical properties. Cavity preparations were made on the occlusal surfaces of premolars. Three HV-GICs (Fuji IX GP, GlasIonomer FX-II and Ketac Molar) and one conventional glass-ionomer cement (C-GIC, Fuji II, as a control) were studied, with specimen subgroups (n=10) for each property measured. After polishing, either immediately (six minutes) after setting or after 24 hours storage, the restored teeth were sectioned in a mesiodistal direction through the center of the model Class I restorations. The presence or absence of interfacial-gaps was measured at 1000× magnification at 14 points (each 0.5-mm apart) along the cavity restoration interface (n=10; total points measured per group = 140). Marginal gaps were similarly measured in Teflon molds as swelling data, together with shear-bond-strength to enamel and dentin, flexural strength and moduli. For three HV-GICs and one C-GIC, significant differences (p<0.05) in gap-incidence were observed between polishing immediately and after one-day storage. In the former case, 80–100 gaps were found. In the latter case, only 9–21 gaps were observed. For all materials, their shear-bond-strengths, flexural strength and moduli increased significantly after 24-hour storage.</p

Symplectic capacity and short periodic billiard trajectory

We prove that a bounded domain $\Omega$ in $\R^n$ with smooth boundary has a periodic billiard trajectory with at most $n+1$ bounce times and of length less than $C_n r(\Omega)$, where $C_n$ is a positive constant which depends only on $n$, and $r(\Omega)$ is the supremum of radius of balls in $\Omega$. This result improves the result by C.Viterbo, which asserts that $\Omega$ has a periodic billiard trajectory of length less than C'_n \vol(\Omega)^{1/n}. To prove this result, we study symplectic capacity of Liouville domains, which is defined via symplectic homology.Comment: 32 pages, final version with minor modifications. Published online in Mathematische Zeitschrif

Antiulcerative properties of crude polyphenols and juice of apple, and Chinese quince extracts

ArticleFOOD CHEMISTRY. 108(2): 488-495 (2008)journal articl

Precision Measurements of d(d,p)t and d(d,n)^3He Total Cross Sections at Big-Bang Nucleosynthesis Energies

Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe $\Omega_b$ with a precision of about 4%. With $\Omega_b$ tightly constrained, comparisons of Big Bang Nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of the d(d,p)t and d(d,n)^3He total cross sections at lab energies from 110 keV to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2% +/- 1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used Nuclear Astrophysics Compilation of Reaction Rates (NACRE). These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.Comment: 15 pages, 11 figures, minor editorial change

Coupling of Josephson flux-flow oscillators to an external RC load

We investigate by numerical simulations the behavior of the power dissipated in a resistive load capacitively coupled to a Josephson flux flow oscillator and compare the results to those obtained for a d.c. coupled purely resistive load. Assuming realistic values for the parameters R and C, both in the high- and in the low-Tc case the power is large enough to allow the operation of such a device in applications.Comment: uuencoded, gzipped tar archive containing 11 pages of REVTeX text + 4 PostScript figures. To appear in Supercond. Sci. Techno

Scaling and exact solutions for the flux creep problem in a slab superconductor

The flux creep problem for a superconductor slab placed in a constant or time-dependent magnetic field is considered. Logarithmic dependence of the activation energy on the current density is assumed, U=U0 ln(J/Jc), with a field dependent Jc. The density B of the magnetic flux penetrating into the superconductor, is shown to obey a scaling law, i.e., the profiles B(x) at different times can be scaled to a function of a single variable. We found exact solution for the scaling function in some specific cases, and an approximate solution for a general case. The scaling also holds for a slab carrying transport current I resulting in a power-law V(I) with exponent p~1. When the flux fronts moving from two sides of the slab collapse at the center, the scaling is broken and p crosses over to U0/kT.Comment: RevTex, 10 pages including 6 figures, submitted to Phys.Rev.

Performance of MAX-DOAS measurements of aerosols at Tsukuba, Japan: a comparison with lidar and sky radiometer measurements

International audienceGround-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were performed at Tsukuba, Japan (36.1° N, 140.1° E), in November?December 2006. The measured spectra of scattered sunlight are analyzed by DOAS and optimal estimation methods to retrieve the aerosol optical depth (?) and the vertical profile of the aerosol extinction coefficient (?) at 476 nm in the lower troposphere. We characterize these retrieved quantities through comparisons with coincident lidar and sky radiometer measurements. The retrieved ? values for layers of 0?1 and 1?2 km agree with lidar data to within 30% and 60%, respectively, for most cases, including partly cloudy conditions. Results similar to ? at 0?1 km are obtained for the retrieved ? values, demonstrating that MAX-DOAS provides the new, unique aerosol dataset in the lower troposphere

Theory of Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} Cross-Whisker Josephson Junctions

Takano {\it et al.} [Phys. Rev. B {\bf 65}, 140513 (2002) and unpublished] made Josephson junctions from single crystal whiskers of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ crossed an angle $\phi_0$ about the $c$ axis. From the mesa structures that formed at the cross-whisker interface, they inferred a critical current density $J_c(\phi_0)$. Like the single crystal results of Li {\it et al.} [Phys. Rev. Lett. {\bf 83}, 4160 (1999)], we show that the whisker data are unlikely to result from a predominantly d-wave order parameter. However, unlike the single crystals, these results, if correct, require the whisker c-axis transport to be coherent.Comment: 5 pages, 4 figures, accepted for publication in Physical Review