Multimodal treatment of Coats-like exudative vitreoretinopathy in Goldmann-Favre syndrome.

Purpose: To report a Coats-like exudative vitreoretinopathy in Goldmann-Favre syndrome.

Observations: A 64 year-old woman with prior diagnosis of retinal dystrophy presented with decreased vision in the right eye (OD). Ophthalmologic examination was remarkable for bilateral arteriolar attenuation, mid-peripheral bony-spicules, and waxy disc pallor.

Linear response theory in stock markets.

Linear response theory relates the response of a system to a weak external force with its dynamics in equilibrium, subjected to fluctuations. Here, this framework is applied to financial markets; in particular we study the dynamics of a set of stocks from the NASDAQ during the last 20 years. Because unambiguous identification of external forces is not possible, critical events are identified in the series of stock prices as sudden changes, and the stock dynamics following an event is taken as the response to the external force.

A New Look on Financial Markets Co-Movement through Cooperative Dynamics in Many-Body Physics.

One of the main contributions of the Capital Assets Pricing Model (CAPM) to portfolio theory was to explain the correlation between assets through its relationship with the market index. According to this approach, the market index is expected to explain the co-movement between two different stocks to a great extent. In this paper, we try to verify this hypothesis using a sample of 3.

Stock markets: A view from soft matter.

Different attempts to describe financial markets, and stock prices in particular, with the tools of statistical mechanics can be found in the literature, although a general framework has not been achieved yet. In this paper we use the physics of many-particle systems and the typical concepts of soft matter to study two sets of US and European stocks, comprising the biggest and most stable companies in terms of stock price and trading. Upon correcting for the center-of-mass motion, the structure and dynamics of the systems are studied (in the European set, the structure is studied for the UK subset only).

Optimization of the magnetic field homogeneity of circular and conical coil pairs.

The magnetic field generated by a pair of coaxial circular loops is analyzed in order to find the optimum separation between the loops for each value of a prescribed homogeneity. For the maximum heterogeneities considered here, 0.1%, 1%, and 10%, the optimum loop spacing is obtained following a graphical procedure so that the length of the homogeneous field region along the axis is the longest possible.

DNA methylation profiles of immune response-related genes in apical periodontitis.

Aim: To investigate the DNA methylation profiles of immune response-related genes in apical periodontitis (AP) lesions.

Methodology: The methylation profiles on the cytosine-phosphate-guanine (CpG) regions of 22 gene promoters involved in inflammation and autoimmunity were assessed in 60 human AP lesions and 24 healthy periodontal ligaments (controls) using a pathway-specific real-time polymerase chain reaction array (EpiTect® Methyl Signature PCR Array Human Inflammatory Response). Differentially methylated genes were subsequently assessed for their mRNA expression.

A model for foreign exchange markets based on glassy Brownian systems.

In this work we extend a well-known model from arrested physical systems, and employ it in order to efficiently depict different currency pairs of foreign exchange market price fluctuation distributions. We consider the exchange rate price in the time range between 2010 and 2016 at yearly time intervals and resolved at one minute frequency. We then fit the experimental datasets with this model, and find significant qualitative symmetry between price fluctuation distributions from the currency market, and the ones belonging to colloidal particles position in arrested states.

Magnetic field homogeneity of a conical coaxial coil pair.

An analytical study of the magnetic field created by a double-conical conducting sheet is presented. The analysis is based on the expansion of the magnetic field in terms of Legendre polynomials. It is demonstrated analytically that the angle of the conical surface that produces a nearly homogeneous magnetic field coincides with that of a pair of loops that fulfills the Helmholtz condition.

Diffusive and Arrestedlike Dynamics in Currency Exchange Markets.

This work studies the symmetry between colloidal dynamics and the dynamics of the Euro-U.S. dollar currency exchange market (EURUSD).

Characterization of a Vascular Endothelial Growth Factor-loaded Bioresorbable Delivery System for Pulp Regeneration.

Introduction: Vascular endothelial growth factor (VEGF) is a signal protein that stimulates angiogenesis and vasculogenesis and has been used in tissue regeneration and pulp regeneration experimental models. The purpose of this study was to develop a delivery system composed of a biodegradable fiber and controlled release of VEGF to promote cell viability and secure an adequate blood supply for the survival of human stem cells of the apical papilla (SCAP) favoring endodontic regenerative procedures.

Methods: We developed a polydioxanone fiber, 50 μm in diameter, loaded with VEGF at a linear concentration of 12.

Permeability of Soft Particles at Electrical Fields.

The influence of the charge on the permeability of microgel particles is studied in the presence of electric fields. Electrophoresis experiments performed on pH-ionizable pNIPAM-AA microgels show that particles behave as permeable spheres when the network is ionized. However, they keep non-permeable in the absence of charge.

Computer simulations of charged colloids in confinement.

We study by computer simulations the interaction between two similarly charged colloidal particles confined between parallel planes, in salt free conditions. Both the colloids and ions are simulated explicitly, in a fine-mesh lattice, and the electrostatic interaction is calculated using Ewald summation in two dimensions. The internal energy is measured by setting the colloidal particles at a given position and equilibrating the ions, whereas the free energy is obtained introducing a bias (attractive) potential between the colloids.

Straightforward estimation of the elastic constants of an isotropic cube excited by a single percussion.

Ritz's method is applied to calculate accurate values of the lowest non-dimensional natural frequencies of a freely vibrating isotropic cube. The dependence of such frequencies and their quotients on Poisson's ratio is established. Vibration of a cube caused by percussion is detected at a point by a laser interferometer.

Gels and microgels for nanotechnological applications.

In recent years, "smart" materials have been the focus of considerable interest, from both fundamental and applied perspectives. Polymer gels are within this category; they respond to specific environmental stimuli by changing their size. Thus, the internal structure, the refractive index, and the mechanical properties of the polymer network change.

Bladder pheochromocytoma: case presentation and the use of OctreoScan for localization of extra-adrenal tumor sites in a pediatric patient.

An eleven year old boy presented with headaches and dizziness associated to micturition. On radiologic imaging, he was found with a bladder mass. The biochemical work up was suggestive of pheochromocytoma.

Colloidal stability of a temperature-sensitive poly(N-isopropylacrylamide/2-acrylamido-2-methylpropanesulphonic acid) microgel.

In this work, a study of the thermally induced flocculation of poly(N-isopropylacrylamide/2-acrylamido-2-methylpropanesulphonic acid) microgel, that is, poly(NIPAM/aMPS) microgel samples is presented. The aggregation process is monitored in continuous by dynamic light scattering measurements. Theoretical explanations are considered and discussed in terms of interaction potentials, paying special attention to osmotic and elastic contributions due to particle interpenetration.

Structure factor scaling in colloidal charge heteroaggregation.

The structure factor, S(q), of a system composed of a 1:1 mixture of oppositely charged colloids undergoing heteroaggregation is studied by Browninan dynamics simulations. A peak develops in S(q) at low wave vectors, which can be scaled for different times to overlap using the scaling of spinodal decomposition, as shown for DLCA. The same master function is obtained for different interaction ranges.

Ionic correlations in highly charge-asymmetric colloidal liquids.

We use electrophoretic mobility (mu) measurements of charged colloidal particles under the presence of multivalent counterions as a probe of the electrostatic correlations between them; they become important for sufficiently high surface charge densities of the colloid (sigma) and result in a decreasing mu upon increasing sigma. The physics of this decrease is the same as that giving rise to charge inversion. We account qualitatively for the observations by considering recent theoretical arguments that assume the counterions next to the colloid surface as a strongly correlated liquid of properties similar to that of a Wigner crystal.

Estimation of dynamic elastic constants from the amplitude and velocity of Rayleigh waves.

In this paper a method is proposed to characterize the elasticity of isotropic linear materials from the generation and detection of an acoustic surface wave. For the calculation of the elastic constants, it is sufficient that only one of the faces of the sample be accessible. The methodology is based on both the measurement of the Rayleigh wave velocity and on the determination of the normal to longitudinal amplitude ratio calculated from the normal and longitudinal components of the displacement of a point.

Static light scattering from microgel particles: model of variable dielectric permittivity.

We perform static light scattering experiments on a dilute suspension of microgel particles and model the resultant form factors Pq by assuming an exponentially decaying dielectric permittivity. The result is that Pq is a Lorentzian function of the scattering wavevector q for length scales greater than the particle size; the width approximately corresponding to twice the particle radius. This simple model reasonably accounts for scattered light from both swollen and shrunken microgel phases.

Oppositely charged colloidal binary mixtures: a colloidal analog of the restricted primitive model.

The equilibrium phase diagram of a colloidal system composed of 1:1 mixture of positive and negative particles with equal charge is studied by means of Monte Carlo simulations. The system is the colloidal analog of the restricted primitive model (RPM) for ionic fluids. A liquid-gas transition is found in the low-temperature-low-density region, similar to the liquid-gas transition in the RPM.

Internal structure of clusters from charge heteroaggregation.

The internal structure of clusters formed by colloidal heteroaggregation of particles with opposite signs of charge is studied by means of computer simulations. Every particle is surrounded by a layer of particles of opposite sign, a second neighbors shell of particles mainly with the same sign, a third one of opposite sign, etc. As the distance from the particle increases, the system becomes more homogeneous and no difference between the numbers of particles with similar or opposite signs of charge can be noticed for distances larger than ten times the particle radius.

Application of the colloidal stability of TiO2 particles for recovery and reuse in solar photocatalysis.

TiO2-catalyst suspensions work efficiently in photocatalysis for wastewater treatment. Nevertheless, once photocatalysis is complete, separation of the catalyst from solution becomes the main problem. Catalyst recovery has been enhanced through charge neutralisation and coagulation with electrolytes at lab and pilot-plant scale (40 L) to evaluate the potential for its separation after photocatalytic degradation of pollutants.

Induced asymmetries in the heteroaggregation of oppositely charged colloidal particles.

Heterocoagulation of cationic and carboxylated polystyrene latexes is studied for a wide range of salt concentrations by static light scattering. The weak character of the surface groups providing the charges allows variation of the relative charge of the systems. Two situations are studied: both latexes with similar surface charges and with very different ones.

Structure formation from mesoscopic soft particles.

In this work, the aggregation of mesoscopic gel particles (soft colloids) has been experimentally investigated. The interaction between particles was controlled through the addition of salt, above the critical coagulation concentration, resulting in aggregation with finite bond energies. Attention has been paid to the structure of the clusters formed in the process as well as to the aggregation kinetics.