Three-dimensional contrast-enhanced ultrasound of the liver: Experience of 92 cases

Three-dimensional contrast-enhanced ultrasound (3D-CEUS) is a combination of three-dimensional ultrasound (3DUS) and contrast-enhanced ultrasound (CEUS). To evaluate the feasibility of 3D-CEUS in liver imaging, investigate possible influencing factors to its image quality, and evaluate the influence of 3D-CEUS to clinical outcome, low acoustic power (mechanical index, 0.08-0.13) 3D-CEUS was carried out in 102 focal liver lesions in 92 patients by using the LOGIQ 9 ultrasound scanner and a volume transducer (frequency range, 2-5 MHz; focusing ability, 2-25 cm in depth; azimuth aperture 5.9 cm). The lesions were classified into two groups: group 1 (n = 51) for characterization and group 2 (n = 51) for local treatment response evaluation. The factors that influenced the image quality of 3D-CEUS were analyzed. The image quality and usefulness of 3D-CEUS between the two groups were compared by using the χ²-test. The results showed that the lesion diameter, location, and scanning route had no significant influence on the image quality in both groups, whereas interfering factors damaged the image quality in group 1. In group 1, during arterial phase, high image quality was more frequently found in hyperenhanced and hypo- or non-enhanced lesions compared with isoenhanced lesions. In group 2, interfering factor and local treatment response had no obvious influence on the image quality. The visualization rate of high image quality was 94.1% (48/51) in group 2 vs. 72.6% (37/51) in group 1 (P = 0.012). The investigators found that 3D-CEUS improved confidence but made no change in diagnosis in 19 (37.3%) of 51 lesions in group 1, whereas 41 (80.4%) of 51 lesions in group 2 (P = 0.000). 3D-CEUS tends to obtain better image quality and lead to higher diagnostic confidence in the lesions for local treatment response evaluation, and perhaps is more useful in this aspect in future clinical settings.     

The principle that generates dissimilar patterns inside aggregates of organisms

Pattern formation and self-organization are phenomena that occur across the board, in animate and inanimate systems. In this paper, we rely on the constructal law to explain the generation of patterns (shapes, structures) in aggregates of organisms-pedestrian crowds and stony corals. In pedestrian crowds a variety of patterns are often observed, from ‘chaotic’ appearances to spontaneous organization in lanes of uniform walking direction. Stony corals and other organisms also present intraspecific variability in shape. We show that flow systems develop in time patterns which provide easier access to the nutrients and space, within a set of constraints imposed by each situation. Flow systems have the freedom to morph their shape in search for architectures that allows them to have greater access to the space that they inhabit. We identify the mechanisms allowing pedestrians to evolve in space and time. We also show that stony corals may develop branched or spherical shapes, depending on which shape performs best in response to the environmental conditions. The constructal law allows systems with complex internal flows to be described and understood for a unified view.     

Physisorption kinetics of electrons at plasma boundaries

Plasma-boundaries floating in an ionized gas are usually negatively charged. They accumulate electrons more efficiently than ions leading to the formation of a quasi-stationary electron film at the boundaries. We propose to interpret the build-up of surface charges at inert plasma boundaries, where other surface modifications, for instance, implantation of particles and reconstruction or destruction of the surface due to impact of high energy particles can be neglected, as a physisorption process in front of the wall. The electron sticking coefficient s_e and the electron desorption time τ_e, which play an important role in determining the quasi-stationary surface charge, and about which little is empirically and theoretically known, can then be calculated from microscopic models for the electron-wall interaction. Irrespective of the sophistication of the models, the static part of the electron-wall interaction determines the binding energy of the electron, whereas inelastic processes at the wall determine s_e and τ_e. As an illustration, we calculate s_e and τ_e for a metal, using the simplest model in which the static part of the electron-metal interaction is approximated by the classical image potential. Assuming electrons from the plasma to loose (gain) energy at the surface by creating (annihilating) electron-hole pairs in the metal, which is treated as a jellium half-space with an infinitely high workfunction, we obtain s_e≈10^-4 and τ_e≈10^-2 s. The product s_eτ_e≈10^-6 s has the order of magnitude expected from our earlier results for the charge of dust particles in a plasma but individually s_e is unexpectedly small and τ_e is somewhat large. The former is a consequence of the small matrix elements occurring in the simple model while the latter is due to the large binding energy of the electron. More sophisticated theoretical investigations, but also experimental support, are clearly needed because if s_e is indeed as small as our exploratory calculation suggests, it would have severe consequences for the understanding of the formation of surface charges at plasma boundaries. To identify what we believe are key issues of the electronic microphysics at inert plasma boundaries and to inspire other groups to join us on our journey is the purpose of this colloquial presentation.     

Studies on the growth,structural, optical,SHG and thermal properties of γ-glycine single crystal: An organic nonlinear optical crystal

Single crystals of the organic nonlinear optical material γ-glycine have been grown in the presence of Zinc sulphate by slow evaporation technique at ambient temperature for the first time. Bulk growth of γ-glycine single crystals was grown by Top-seeded solution growth method. The γ-phase of glycine was confirmed by powder X-ray diffraction and the FTIR analysis. Elemental analysis CHN was performed to confirm the non-inclusion of zinc sulphate species into the solution. Inductively coupled plasma optical emission spectrometry study (ICP-OES) was employed to quantify the concentration of Zinc element in the grown γ-glycine single crystals. The optical transmission was ascertained from UV–Vis–NIR spectrum. The optical band gap was estimated for γ-glycine single crystal using UV–Vis–NIR study. Differential scanning calorimetry analysis was employed to explore information about thermal stability, phase transition and melting point of the grown crystal. The second harmonic generation relative efficiency was measured by Kurtz and Perry powder technique.     

A version of Stöber synthesis enabling the facile prediction of silica nanospheres size for the fabrication of opal photonic crystals

A sol-gel synthesis procedure based on the method proposed by Stöber et al. (J Colloid Interface Sci 26:302–315, 1968) has been adopted for the one-step preparation of mono-dispersed silica nanospheres. An excellent control of the particle diameter over a wide range is obtained by varying the amount of silicon alkoxide only, while the concentration of all other components is kept fixed: this allows the fabrication of artificial opals with a finely tuned and precisely predictable lattice parameter.     

Steps and facets at the surface of soft crystals

We consider the shape of crystals which are soft in the sense that their elastic modulus μ is small compared to their surface tension γ, more precisely μa < γ where a is the lattice spacing. We show that their surface steps penetrate inside the crystal as edge dislocations. As a consequence, these steps are broad with a small energy which we calculate. We also calculate the elastic interaction between steps a distance d apart, which is a 1/d ² repulsion. We finally calculate the roughening temperatures of successive facets in order to compare with the remarkable shapes of lyotropic crystals recently observed by Pieranski et al. [#!Pieranski!#,#!EPJ!#]. Good agreement is found. Received 25 June 2001     

Luminescence properties of Ba2NaNb5O15 crystals activated with Sm, Eu, Tb or Dy ions

Single crystals of Ba₂NaNb₅O₁₅ (BNN) singly doped with Sm³⁺, Eu³⁺, Tb³⁺ or Dy³⁺ have been grown by means of the flux growth method. Their visible emission and excitation spectra and the decay profiles of the luminescence have been measured at room temperature. All spectral features are significantly inhomogeneously broadened in consequence of the structural disorder of the host and of the doping mechanisms. The analysis of the observed spectra allows formulating an hypothesis about the site occupancy of the active ions in the BNN lattice.     

Light propagation and oscillations in two-dimensional graded square photonic lattices

We have studied the optical oscillations and transitions in two-dimensional graded square photonic lattices (GSPL) formed by evanescently coupled optical waveguide arrays with parabolic confinements in all transverse directions. When we retain only the orthogonal couplings, decoupled one-dimensional models can be used to obtain the various normal modes, which correspond to a variety of optical oscillations. Six different combinations of Bloch oscillation (BO), dipole oscillation (DO), and reflections from the boundaries of finite lattice are classified on the phase diagram. If we include the diagonal couplings, transitions among various oscillations are obtained with the Hamiltonian optics approach and confirmed by the field-evolution analysis. We studied in detail a typical example in which a switching occurs from the constituent BO and DO to both DOs in the two orthogonal directions. The method to analyze the complex field evolution in GSPL can be extended to similar systems with different types of lattices and/or confinements.     

Orientationally polarized dependence of image contrast in doped lithium niobate crystals

In lithium niobate crystals doped with photorefractive iron and copper admixtures when lightening objects with broadband incoherent radiation one can observe typical orientation and polarized dependences of image contrast. The record does not realize at orientation of light bands in the image parallel to the polar axis of the crystal.     

Oscillatory zoning caused by oscillating surface relaxations

Oscillatory zoning is a spatial variation in the composition of minerals. It has been observed in many different minerals and a variety of mechanisms have been proposed to explain it. We propose an equilibrium model of oscillatory zoning in which the variations in composition stabilise a ferroelastic phase. This results in a sinusoidal variation in composition. We expect that this mechanism could account for oscillatory zoning found in minerals with oscillatory surface relaxations. Received 9 March 1999