Wetting of liquid droplets on two parallel filaments

Droplet wetting on two parallel filaments may assume a barrel-shaped morphology or a liquid bridge depending upon the filament diameter and spacing, droplet volume, and contact angle. This paper is aimed to examine the dependency of droplet wetting length upon the above parameters. In the process, morphology of either a barrel-shaped droplet or a liquid bridge sitting on two parallel filaments is determined numerically by using surface finite element method (SFEM). Variation of wetting length with contact angle is examined at varying droplet volume, filament spacing, and droplet morphology. It is found that the droplet wetting length increases with decreasing filament spacing ratio as well as contact angle while it also increases with the growth of droplet volume. The dependency of wetting length upon contact angle behaves sensitive to filament spacing in the case of stable liquid bridges, while it exhibits nearly constant sensitivity to the contact angle in the case of barrel-shaped droplets. The quantitative relations yielded in this study can be considered as characteristic curves applicable for a variety of droplet-on-filament systems, particularly useful to wetting property characterization of filaments, micro liquid delivery, biological cell manipulation, etc.     

Measurement of Einstein-Podolsky-Rosen-type flavor entanglement in Upsilon(4S) --> B0 B0 decays

The neutral B meson pair produced at the Upsilon(4S) should exhibit a nonlocal correlation of the type discussed by Einstein, Podolsky, and Rosen. We measure this correlation using the time-dependent flavor asymmetry of semileptonic B(0) decays, which we compare with predictions from quantum mechanics and two local realistic models. The data are consistent with quantum mechanics, and inconsistent with the other models. Assuming that some B pairs disentangle to produce B(0) and B(0) with definite flavor, we find a decoherent fraction of 0.029 +/ -0.057, consistent with no decoherence.     

Dynamical Hopf bifurcation in piezoelectric semiconductor resonators

Time-dependent Hopf bifurcations in the current-voltage characteristics of piezoelectric semiconductor resonators were investigated experimentally. The switching transition between acoustic bistable states was observed under a quasi-static variation of applied voltage. The peculiar pulse responses of the resonant currents were observed when the rise-time of the pulses exceeded the eigen-period of the system. The existence of a metastable state in the dynamical Hopf bifurcation are discussed.     

Three-dimensional susceptibility-weighted imaging at 3 T using various image analysis methods in the estimation of grading intracranial gliomas

Object

Although three-dimensional (3D), high-spatial resolution susceptibility-weighted imaging (SWI) appears to be valuable in the evaluation of central nervous system gliomas, several evaluation methods are proposed in the literature. The purpose of this study was to evaluate the use of 3D SWI for grading intracranial gliomas with various analysis methods.

Materials and Methods

Twenty-three patients suspected of having gliomas participated in this study. SWI was performed in addition to conventional MR sequences. In 15 cases, post-gadolinium enhanced SWI was also obtained. Imaging evaluation criteria were conventional grade, hypointensity ratio in the tumor-dominant structure of hypointensity on SWI (hemorrhage or vascular structure) and presence of abnormal enhancement surrounding the tumor.

Results

Mean grading scores of conventional grade showed no statistically significant difference among WHO grades. Mean grading scores of hypointensity ratios in the tumor were higher for WHO Grades 3 and 4 than for lower grade tumors (P=.05, Mann–Whitney U test). Hemorrhagic foci were more frequently seen in the higher grade tumor. Post-contrast susceptibility-weighted images of five of 11 WHO Grade 3 and 4 cases showed bright enhancement surrounding the tumor, suggesting a breakdown of the blood–brain barrier.

Conclusions

SWI at 3 T may be a useful method to analyze the structural characteristics of gliomas and to evaluate pathology in vivo. Assessment of hypointensity ratios in the glioma was the most preferable method in grading glioma. However, more studies, specifically concerning a suitable method for image analysis, are needed to establish SWI at 3 T as a useful tool in clinical routine.