The dipole moment of a water molecule in liquid water differs from that of an isolated one because each molecule is further polarized by the electric field of its neighbours. In this work a formula for the spatial dependence of the relative permittivity of an electrolyte near a highly charged surface is obtained in which the mutual influence of the water molecules is taken into account by means of the cavity field. The orientational ordering of water dipoles is considered in the saturation regime. It is predicted that the relative permittivity of an electrolyte solution near the highly charged surface (i.e. in saturation regime) may be substantially decreased due to orientational ordering of water (saturation effect) and depletion of water molecules (excluded volume effect) due to accumulation of counterions.
COBISS.SI-ID: 9337940
A novel game-theoretic framework for landmark-based image segmentation is presented. Landmark detection is formulated as a game, in which landmarks are players, landmark candidate points are strategies, and likelihoods that candidate points represent landmarks are payoffs, determined according to the similarity of image intensities and spatial relationships between the candidate points in the target image and their corresponding landmarks in images from the training set. The solution of the formulated game-theoretic problem is the equilibrium of candidate points that represent landmarks in the target image and is obtained by a novel iterative scheme that solves the segmentation problem in polynomial time. The performance of the proposed framework was evaluated for segmentation of lung fields from chest radiographsand heart ventricles from cardiac magnetic resonance crosssections. The comparison to other landmark-based segmentation techniques shows that the results obtained by the proposed game-theoretic framework are highly accurate and precise.
COBISS.SI-ID: 9231956
Groupwise registration is concerned with bringing a group of images into best spatial alignment. If images in the group are from different modalities, then the intensity correspondences across the images can be modeled by the joint density function of the co-occurring image intensities. We propose a so-called treecode registration method for groupwise alignment of multi-modal images that uses a hierarchical intensity space subdivision scheme through which an efficient, yet sufficiently accurate estimation of the (high-dimensional) joint density function based on the Parzen kernel method is computed. To simultaneously align a group of images, a gradient-based joint entropy minimization was employed that also uses the same hierarchical intensity space subdivision scheme. If Hilbert kernel is used for the joint density estimation, then the treecode method requires no data-dependent bandwidth selection and is thus fully automatic. The treecode method was compared to the ensemble clustering method on four different publicly available multi-modal image datasets and on a synthetic mono-modal image dataset. The obtained results indicate that the treecode method has similar, and for two datasets even superior performances compared to the ensemble clustering method in terms of registration error and success rate.
COBISS.SI-ID: 9111636
The aim of this study was to assess the potential for disruption of the lipid bilayer by C-60 suspended in water. Electromobility measurements show significant negative surface charge on the C-60 nanoparticles suspended in a glucose solution and a zeta potential of -26 mV and hydrodynamic radii of approximately 2 nm. Phase contrast microscopy and computer aided image analysis results show that C-60 causes shape transformations and rupture of unilamellar phospholipid vesicles, indicative of changes in their average mean curvature. Small-angle X-ray scattering reveals that C-60 provokes disruptions of external membranes of multilamellar vesicles only after freeze and thaw cycles. Here, the liposomes undergo breakage and annealing steps which increase the probability for fullerenes to insert into the MLVs. Our experimental findings confirm the potential of C-60 to reconstruct lipids in biological membranes. This research enhances our understanding of the impact of engineered nanoparticles on cell membranes.
COBISS.SI-ID: 2451279
A new method is introduced for analysis of interactions between time-dependent coupled oscillators, based on the signal they generate. It distinguishes unsynchronized dynamics from noise-induced phase-slips and enables the evolution of the coupling functions and other parameters to be followed. It is based on phase dynamics, with Bayesian inference of the time-evolving parameters achieved by shaping the prior densities to incorporate knowledge of previous samples. The method is tested numerically and applied to reveal and quantify the time-varying nature of cardiorespiratory interactions.
COBISS.SI-ID: 9358420