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We used Monte Carlo simulations with an elastically anisotropic pairwise potential to simulate the equilibrium structure of chiral and achiral nematic liquid crystals in spherical confinement under perpendicular and tangential strong anchoring. The stable structures are obtained by a quenching process, where the temperature is a parameter of the system. We calculate and map the distribution of elastic energy corresponding to splay, twist, and bend. Furthermore, we study the effect of changing the ratio of the elastic constants for achiral and low chirality droplets and found a diverse scenario of possible structures. The method described here allows the introduction of temperature and elastic anisotropy naturally within its framework. It is simpler to implement and faster to execute than the Landau-de Gennes (LdG) method used for simulating liquid crystal droplets. [ABSTRACT FROM AUTHOR]

Aims: This study aimed to explore factors related to non‐adherence to exergaming in patients with heart failure. Methods and results: Data from patients in the exergame group in the HF‐Wii trial were used. Adherence to exergaming was defined as playing 80% or more of the recommended time. Data on adherence and reasons for not exergaming at all were collected during phone calls after 2, 4, 8, and 12 weeks. Logistic regression was performed between patients who were adherent and patients who were non‐adherent. Secondly, a logistic regression was performed between patients who not exergamed at all and patients who were adherent to exergaming. Finally, we analysed the reasons for not exergaming at all with manifest content analysis. Almost half of the patients were adherent to exergaming. Patients who were adherent had lower social motivation [odds ratio (OR) 0.072; 95% confidence interval (CI) 0.054–0.095], fewer sleeping problems (OR 0.84; 95% CI 0.76–0.092), and higher exercise capacity (OR 1.003; 95% CI 1.001–1.005) compared with patients who were non‐adherent. Patients who not exergamed at all had lower cognition (OR 1.18; 95% CI 1.06–1.31) and more often suffered from peripheral vascular disease (OR 3.74; 95% CI 1.01–13.83) compared with patients who were adherent to exergaming. Patients most often cited disease‐specific barriers as a reason for not exergaming at all. Conclusions: A thorough baseline assessment of physical function and cognition is needed before beginning an exergame intervention. It is important to offer the possibility to exergame with others, to be able to adapt the intensity of physical activity. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this review was to explore the potential clinical application of unconventional non-amino acid PET radiopharmaceuticals in patients with gliomas. Methods: A comprehensive search strategy was used based on SCOPUS and PubMed databases using the following string: ("perfusion" OR "angiogenesis" OR "hypoxia" OR "neuroinflammation" OR proliferation OR invasiveness) AND ("brain tumor" OR "glioma") AND ("Positron Emission Tomography" OR PET). From all studies published in English, the most relevant articles were selected for this review, evaluating the mostly used PET radiopharmaceuticals in research centers, beyond amino acid radiotracers and 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG), for the assessment of different biological features, such as perfusion, angiogenesis, hypoxia, neuroinflammation, cell proliferation, tumor invasiveness, and other biological characteristics in patients with glioma. Results: At present, the use of non-amino acid PET radiopharmaceuticals specifically designed to assess perfusion, angiogenesis, hypoxia, neuroinflammation, cell proliferation, tumor invasiveness, and other biological features in glioma is still limited. Conclusion: The use of investigational PET radiopharmaceuticals should be further explored considering their promising potential and studies specifically designed to validate these preliminary findings are needed. In the clinical scenario, advancements in the development of new PET radiopharmaceuticals and new imaging technologies (e.g., PET/MR and the application of the artificial intelligence to medical images) might contribute to improve the clinical translation of these novel radiotracers in the assessment of gliomas. [ABSTRACT FROM AUTHOR]

We analyze a new space–time fractional diffusion equation encompassing different diffusion processes in d-dimensions. The first-order time derivative is replaced with a time derivative of the Caputo type of arbitrary order β; the spatial-fractional operator of Riesz–Feller or Riesz–Weyl type is replaced with its extension to d-dimensions, defined by means of an extended Fourier transform. The mathematical problem with the spatial-fractional operator proposed here is formulated to tackle anomalous diffusion in heterogeneous media (fractal structures) and incorporating power-law distributions. A formal solution is proposed using the Green function method which, for appropriate initial and boundary conditions, can be expressed in terms of the generalized H-function of Fox—a typical track of anomalous diffusive processes. These mathematical tools provide a new powerful framework to model anomalous diffusion and relaxation problems in heterogeneous media. [ABSTRACT FROM AUTHOR]

This research evaluates the fracture behavior of concrete with reactive magnesium oxide (MgO). Replacing cement with MgO is an attractive option for the concrete industry, mainly due to sustainability benefits and reduction of shrinkage. Four different MgO's from Australia, Canada, and Spain were used in the concrete mixes, as a partial substitute of cement, at 5%, 10%, and 20% (by weight). The fracture toughness (KI) intensity factor and the stress–strain softening parameters of the wedge split test were evaluated after 28 days. The experimental results showed that the replacement of cement with MgO reduced the fracture energy between 13% and 53%. Moreover, the fracture energy was found to be correlated with both compressive strength and modulus of elasticity. A well-defined relationship between these properties is important for an adequate prediction of the non-linear behavior of reinforced concrete structures made with partial replacement of cement with MgO. [ABSTRACT FROM AUTHOR]

This article presents the study of the dependence of the Steinmetz coefficients on the technological processing parameters for commercially available SMC Somaloy 3P 700. The work was carried under a Box–Behnken design of experiments considering pressing pressure, heat treatment temperature, and soaking time as relevant factors over the total power losses. Based on the values of $K_{H}$ , $x$ , and $K_{D}$ extracted from the measured losses, equations for predicting the values of the Steinmetz coefficients with the processing parameters as inputs were generated. The results presented high correlation between the measured and modeled losses and can easily be applied to electrical machine design software. [ABSTRACT FROM AUTHOR]

We investigate a connection between random walks and nonlinear diffusion equations within the framework proposed by Einstein to explain the Brownian motion. We show here how to properly modify that framework in order to handle different physical scenarios. We obtain solutions for nonlinear diffusion equations that emerge from the random walk approach and analyse possible connections with a generalized thermostatistics formalism. Finally, we conclude that fractal and fractional derivatives may emerge in the context of nonlinear diffusion equations, depending on the choice of distribution functions related to the spreading of systems. [ABSTRACT FROM AUTHOR]

We present a short overview of recent investigations of the equilibrium tilt angle profile in a cell limited by two concentric cylinders filled with nematic liquid crystals (NLC), both in presence and in absence of an external electric field. The analyses are carried out by recalling some recent results obtained in the framework of the elastic continuum theory and Monte Carlo (MC) simulations, or suitable combinations of both approaches. These are very powerful tools to face the richness of the configurations of NLC in complex geometries. In particular, they are helpful in providing a comprehension of the molecular organisation of these systems for what concerns the spontaneous Fréedericksz-like transition, connected with the phenomenon of escaping into the third dimension. Some concluding remarks and perspectives points towards some remarkable features of confined systems in soft matter. [ABSTRACT FROM AUTHOR]

Resumen El cáncer de próstata (CaP) representa el tumor maligno más frecuente en los varones, pero según las directrices de la European Association of Urology (EAU) no deben realizarse cribados masivos para el diagnóstico de CaP debido a problemas relacionados con el sobrediagnóstico y sobretratamiento. El diagnóstico clínico precoz es posible, principalmente basado en el tacto rectal y la determinación del antígeno prostático específico (PSA). Sin embargo, el único test que puede determinar la presencia de un CaP es la biopsia guiada por ecografía, obteniendo múltiples muestras, la cual tiene un elevado valor pronóstico. En este contexto, la imagen diagnóstica juega un importante papel tal como lo confirmó la EAU, que en una actualización de 2016 de su guía clínica sobre CaP estableció la importancia de la tomografía por emisión de positrones (PET) con 11 C- o 18 F-colina combinada con la tomografía computarizada (TC) para individualizar la recidiva local, la afectación de ganglios linfáticos y la diseminación metastásica en todos los estadios. En consecuencia, en 2017, la European Association of Nuclear Medicine (EANM) junto con la Society of Nuclear Medicine and Molecular Imaging (SNMMI) compartieron nuevas directrices para la PET/TC con 68 Ga-antígeno de membrana prostático específico (PSMA) para ayudar a los médicos en la recomendación, realización e interpretación de los estudios PET/TC en pacientes con CaP. De esta manera, el objetivo de este «artículo de evidencia» es definir el algoritmo diagnóstico actual en el CaP para incrementar el nivel de confianza global en el enfoque de un tema tan crucial. Prostate Cancer (PCa) represents the most common malignant tumor in men but according to the European Association of Urology (EAU) guidelines, a mass screening for PCa diagnosis should not be performed due to over-diagnosis and over-treatment related problems. An early clinical diagnosis is possible, mainly based on digital rectal examination and Prostatic Specific Agent (PSA) testing. However, the only mandatory test to define the presence of PCa is ultrasound guided-biopsy, obtained on multiple samples, which has also a high prognostic value. In this context, diagnostic imaging plays an important role as confirmed by EAU that in a 2016 update of their guidelines on PCa stated the importance of Positron Emission Tomography (PET) with 11 C- or 18 F-choline combined with computed tomography (CT) to identify local relapse, lymph node involvement and metastatic spread at all stages. Consequently, in 2017, the European Association of Nuclear Medicine (EANM) together with the Society of Nuclear Medicine and Molecular Imaging (SNMMI) published new guidelines for 68 Ga-Prostate Specific Membrane Antigen (PSMA) PET/CT to help physicians in the recommendation, execution and interpretation of PET/CT scans in patients with PCa. Thus, the aim of this ‘evidence paper’ is to define the current diagnostic algorithm in PCa in order to increase the general level of confidence in approaching such a crucial topic. [ABSTRACT FROM AUTHOR]

This work focuses on the striped pattern formation of cholesteric liquid crystals confined in a hybrid aligned cell. The study is performed by means of Monte Carlo simulations. This pattern formation was studied with a chiral molecular additive pair potential proposed for cholesterics by discretizing the Frank free energy density. Experimentally, the thickness of slab to cholesteric pitch ratio (d/p0) is fundamental to describe how the stripes will behave, but no deep studies on the role of anchoring energy have been reported to date. According to simulation results, it is possible to observe a textural transition that depends both on the material's physical parameters and the anchoring strength. Such transition, from planar to a spontaneous striped pattern structure, occurs when the anchoring energy at the homeotropic surface reaches a critical valueJcrit. Moreover, the oscillation amplitudes of directors immediately below the top surface changes with anchoring energy and with the physical parameters of the host liquid crystals. [ABSTRACT FROM PUBLISHER]

Representation of the oblique helicoidal structure with a nanometric pitch of typical of the twist-bend nematic phase. A variational approach is employed to search for exact solutions describing the director profile in the framework of an extended Frank elastic energy density. This extension of the energy density of the usual nematic phase adds an extra element of symmetry represented by the axis, thus augmenting the number of possible phases described by the elastic energy, which includes modulated phases. The solutions corresponding to these phases are searched by exploring the symmetry properties and the existence of conserved quantities, which permits us to reduce the general solution of the variational problem to quadratures. This approach may be particularly useful to investigate the existence and stability of the recently discovered twist-bend nematic phase as well as to predict the orientational properties of other periodically modulated phases. [ABSTRACT FROM PUBLISHER]

Presents information on a study which proposed a model for determining the steady-state distribution of ionic charges in a liquid sample. Role of a surface in a weak electrolyte solution; Equations used in the calculations of the model.

One-dimensional diffusion problems in bounded porous media characterized by the presence of nonlocal interactions are investigated by assuming a Darcy's constitutive equation of convolution integral type. A power law attenuation function is implemented: Analogies and differences of the flow-rate-pressure law with respect to other nonlocal and fractal models are outlined. By means of the continuity relationship, the fractional diffusion equation is then derived. It involves spatial Riemann-Liouville derivatives with a noninteger order consisting of between 1 and 2. The solution is obtained numerically using fractional finite differences, and results are presented in both the transient and the steady-state regimes. Eventually, the physical meaning of fractional operators is discussed and potential applications of the analysis are suggested. [ABSTRACT FROM AUTHOR]

We revisit the classical problem of the molecular orientation inside a hybrid cell filled with liquid-crystals with various elastic constant anisotropies by means of Monte Carlo simulations using the Gruhn-Hess effective pair potential. We find some unstable defect lines and we discuss their arising in the system. We study the effects of the elastic anisotropy on the profiles of the director close to the surface with weak anchoring. Our findings indicate that the elastic theory and computer simulations are in good qualitative agreement while quantitatively some discrepancies are found mainly when the ratio K11/K33is larger than one. [ABSTRACT FROM AUTHOR]

From the elastic point of view, the twist-bend nematic phase, (NTB), has a ground state characterised by a spontaneous bend with a precession of the directornalong the direction of an axist. The tilt angle θ formed between the directornand the axistgives rise to a heliconical structure with a nanometric helical pitchp. Using an elastic continuum theory recently proposed as an extension of the Frank energy for these materials, we investigate the influence of an external magnetic field on the pitch of the NTBphase. For a material with positive magnetic susceptibility anisotropy, when the magnetic fieldHis perpendicular tot, it is shown that the pitch of the nematic directornprecession increases withH, and at a critical value ofit becomes infinite as in a cholesteric liquid crystal, that is, one gets a uniform orientation ofn. Our results include the behaviour of a cholesteric under field as a limiting case, and are obtained in the simple case where θ is assumed as uniform throughout the sample. [ABSTRACT FROM AUTHOR]

Even though in several countries there are regulations allowing, even at a small scale, the use of recycled aggregates in concrete production, practice shows that the cases in which this solution is implemented are still rare. However, in most of these countries the use of the fine Fraction of the Recycled Aggregates (FRA) from general Construction and Demolition Waste (CDW) is restricted or even banned. More recent studies have shown that the use of FRA is feasible and that the resulting mechanical performance is perfectly acceptable. This paper presents the flexural tests performed on reinforced concrete beams made with replacement of natural by recycled fine aggregates, comparing the results obtained in terms of ultimate load and deformation, ductility, bearing capacity and cracking with those from a reference beam, made with conventional concrete. [ABSTRACT FROM AUTHOR]

The recently discovered twist-bend nematic phase, Ntb, is a non-uniform equilibrium nematic phase that presents a spontaneous bend with a precession of the nematic director,n, on a conical helix with a tilt angleθand helical pitchP. The stability of the Ntbphase has been recently demonstrated from the elastic point of view by extending the Frank elastic energy density of the nematic phase to include the symmetry element of the helical axis,t. In the present article, we investigate the influence of an external bulk field (magnetic or electric) on the Ntbphase. Using symmetry arguments we derive the expression for the flexoelectric polarisation in twist-bend nematic phases. We show that, besides the standard contribution related to the spatial variation of the nematic director, two new contributions connected with the existence of the helical axis appear. In the ground state, where the nematic deformation is a pure heliconical deformation, the new contribution vanishes identically, and the total flexoelectric polarisation is perpendicular to the nematic director. Furthermore, as an example, we study the role of an external magnetic field applied parallel to the helical axis for a material with positive magnetic susceptibility anisotropy. We show that the field modifies the range of values of the coupling parameter between the director and the helical axis, thus shifting the interval of values for which this coupling results in the Ntbphase. [ABSTRACT FROM PUBLISHER]

Diffusion of particles in a heterogeneous system separated by a semipermeable membrane is investigated. The particle dynamics is governed by fractional diffusion equations in the bulk and by kinetic equations on the membrane, which characterizes an interface between two different media. The kinetic equations are solved by incorporating memory effects to account for anomalous diffusion and, consequently, non-Debye relaxations. A rich variety of behaviours for the particle distribution at the interface and in the bulk may be found, depending on the choice of characteristic times in the boundary conditions and on the fractional index of the modelling equations. [ABSTRACT FROM AUTHOR]

A joint analysis of down-hole (DH) and multichannel analysis of surface waves (MASW) measurements offers a complete evaluation of shear wave velocity profiles, especially for sites where a strong lateral variability is expected, such as archeological sites. In this complex stratigraphic setting, the high 'subsoil anisotropy' (i.e., sharp lithological changes due to the presence of anthropogenic backfill deposits and/or buried man-made structures) implies a different role for DH and MASW tests. This paper discusses some results of a broad experimental program conducted on the Palatine Hill, one of the most ancient areas of the city of Rome (Italy). The experiments were part of a project on seismic microzoning and consisted of 20 MASW and 11 DH tests. The main objective of this study was to examine the difficulties related to the interpretation of the DH and MASW tests and the reliability limits inherent in the application of the noninvasive method in complex stratigraphic settings. As is well known, DH tests provide good determinations of shear wave velocities (Vs) for different lithologies and man-made materials, whereas MASW tests provide average values for the subsoil volume investigated. The data obtained from each method with blind tests were compared and were correlated to site-specific subsurface conditions, including lateral variability. Differences between punctual (DH) and global (MASW) Vs measurements are discussed, quantifying the errors by synthetic comparison and by site response analyses. This study demonstrates that, for archeological sites, V profiles obtained from the DH and MASW methods differ by more than 15 %. However, the local site effect showed comparable results in terms of natural frequencies, whereas the resolution of the inverted shear wave velocity was influenced by the fundamental mode of propagation. [ABSTRACT FROM AUTHOR]

The aim of this paper is to evaluate the influence of the crushing process used to obtain recycled concrete aggregates on the performance of concrete made with those aggregates. Two crushing methods were considered: primary crushing, using a jaw crusher, and primary plus secondary crushing (PSC), using a jaw crusher followed by a hammer mill. Besides natural aggregates (NA), these two processes were also used to crush three types of concrete made in laboratory (L20, L45 e L65) and three more others from the precast industry (P20, P45 e P65). The coarse natural aggregates were totally replaced by coarse recycled concrete aggregates. The recycled aggregates concrete mixes were compared with reference concrete mixes made using only NA, and the following properties related to the mechanical and durability performance were tested: compressive strength; splitting tensile strength; modulus of elasticity; carbonation resistance; chloride penetration resistance; water absorption by capillarity; water absorption by immersion; and shrinkage. The results show that the PSC process leads to better performances, especially in the durability properties. [ABSTRACT FROM AUTHOR]

Introduction Bleeding disorders are certainly one of the most difficult health conditions among health professionals. The haemophilia requires special care in dentistry mainly due to highly vascularized oral cavity. Aim The objective of this study was to determine oral health conditions of children and adolescents with haemophilia at a haematology centre. Methods The sample was composed of 40 children and adolescents aged 1-18 years. Data collection occurred by means of a questionnaire about social and economical conditions, and an examination of the oral cavity. The decayed, missing and filled deciduous teeth (dmft), decayed, missing and filled permanent teeth (DMFT) and gingival bleeding (allows the determination of gingival bleeding) epidemiological indexes were evaluated. Results When evaluating caries experience, the mean value for the dmft index was 3.4 for the deciduous dentition, DMFT score of 0.9 for mixed-dentition, and 2.9 for permanent dentition. The mean value for the gingival bleeding index was similar in all three phases of development, showing a mean value of 1.74. Conclusion The majority of the children and adolescents demonstrated unsatisfactory oral health. [ABSTRACT FROM AUTHOR]

Nematic systems confined to a bounded volume are particularly interesting because they present stable structure defects induced by the anchoring conditions on the surface. Here we present a Monte Carlo study of a hybrid nematic film with various strengths of coupling with the surfaces. [ABSTRACT FROM PUBLISHER]

This study analyses the effects of heat treatments in oxidative atmosphere on the mechanical and microstructural properties of a fiber-reinforced weak interface composite (UMOX™) which is composed of a mullite-SiOC matrix and Nextel™ 610 fibers with fugitive coatings. Composites of different porosity grades, depending on the polymer infiltration and pyrolysis cycle, are exposed to 1000 and 1200 °C for 50 h. The exposure provokes the formation of silica, which leads to matrix densification and the formation of silica bridges at the fiber–matrix interface, resulting in an increased interfacial bonding strength. Consequently, the fracture toughness and the flexural strength are significantly reduced. The study confirms that SiOC-based materials are suitable for an application at high temperatures in oxygen-rich atmospheres up to 1000 °C. It is, however, important to consider the microstructural changes and thereby induced decrease of the overall mechanical performance during a high-temperature use. [ABSTRACT FROM AUTHOR]

The adsorption phenomenon of neutral particles from the limiting surfaces of the sample in the Langmuir approximation is investigated. The diffusion equation regulating the redistribution of particles in the bulk is assumed to be of hyperbolic type, in order to take into account the finite velocity of propagation of the density variations. We show that in this framework the condition on the conservation of the number of particles gives rise to a nonlocal boundary condition. We solve the partial differential equation relevant to the diffusion of particles by means of the separation of variables, and present how it is possible to obtain approximated eigenvalues contributing to the solution. The same problem is faced numerically by a finite difference algorithm. The time dependence of the surface density of adsorbed particles is deduced by means of the kinetic equation at the interface. The predicted non-monotonic behavior of the surface density versus the time is in agreement with experimental observations reported in the literature, and is related to the finite velocity of propagation of the density variations. [ABSTRACT FROM AUTHOR]

Davallia repens and its close relatives have been identified as a species complex in this study because of the existence of continuously morphological variation. To decipher its evolutionary history, integrated methodologies were applied in this study including morphology, cytology, reproductive biology and molecular phylogeny. Analysis of morphological characters reveals several important discriminating characteristics, such as the shape of stipe scales, frond and indusium. Both diploid and polyploid forms are present in the complex and reproduce sexually and by apogamy, respectively. The incongruence between cpDNA and nDNA phylogeny indicates a hybrid origin for most polyploid individuals. Based on the present results, we hypothesize that there were at least two ancestral lineages distributed in the Malesian region. Through hybridization, polyploidization and apogamy, some polyploid genotypes dispersed outwards to shape the extant distribution. [ABSTRACT FROM AUTHOR]

The fundamental equations of a Poisson-Boltzmann model to investigate the effects of a de-localized surface interaction energy on the ionic adsorption in a finite-length electrolytic cell are solved. Two distinct, physically plausible, forms of the interaction energy, having different decaying spatial behavior are explicitly analyzed. The surface and chemical potentials are evaluated in terms of the strengths of these van der Waals-like interactions characterizing the adsorption energy. A quantity playing the role of an integral double-layer capacitance of the cell is introduced and its behavior is investigated as a function of the parameters of the adsorption potentials. [ABSTRACT FROM AUTHOR]

The electrical impedance response of six nematic liquid crystals samples is analyzed by means of an extension of the Poisson-Nernst-Planck diffusional model. This formulation includes fractional derivatives of distributed order governing the behavior of the bulk density of mobile charges, whose solutions are subjected to integro-differential equations accounting for the boundary conditions. The role of the intrinsic surface lengths involved in the adsorption-desorption phenomena at the electrodes is emphasized, in order to analyze the frequency dependence of the real and imaginary parts of the electrical impedance experimentally obtained. [ABSTRACT FROM AUTHOR]

We investigate the director relaxation of a nematic liquid crystal cell by considering the molecular moment of inertia, surface viscosity and anchoring energies at the boundaries. The problem solved here corresponds to a more complete description of the nematic director reorientation, since it incorporates ingredients that are usually neglected due to the mathematical difficulty raised by the moment of inertia and surface viscosity. In order to face this problem, we apply the half space approximation for the sample with the surfaces characterized by a time dependent easy direction, which can be mechanically or optically induced in the system. The results show that both, the molecular moment of inertia and the surface viscosity, have influence on the relaxation process of the director. In particular, the presence of the molecular moment of inertia introduces a finite phase velocity and, consequently, leads to a non-instantaneous response time for the distortion propagation in a liquid crystal cell. [ABSTRACT FROM AUTHOR]

A hybrid (weak-strong anchoring) cylindrical cell with antagonistic boundary conditions (planar–homeotropic) at the outer confining surface and at a central coaxial cylindrical core and filled with nematic liquid crystals is investigated by means of the Elastic Theory and Monte Carlo Simulations. The director orientation profile on the surface characterized by weak anchoring is built as a function of the extrapolation length and other relevant parameters. By considering the angle on the surface as an order parameter, a transition in the orientation is found when the extrapolation length becomes smaller than a critical value and the orientation of the surface with strong anchoring is dominant. The order parameter critical exponent is numerically calculated, and the mean field value (β≈1/2) is found in all cases. These transitions are essentially confirmed by Monte Carlo simulations even if some numerical discrepancies are found. The analysis show similarities between planar and cylindrical geometries, but non-usual consequences are found more easily in the latter one. [ABSTRACT FROM AUTHOR]

The effect of a localized surface viscosity on the relaxation of a pre-existing deformation in a nematic liquid crystal cell is perturbatively analyzed in the presence of an external field. When the surface viscosity of the system is small enough to use perturbation developments, approximated solutions can be obtained describing the space-time profile of the director angle. It is shown that if the surface viscosity increases, the relaxation becomes slower when compared to the case corresponding to the absence of viscosity. The temporal behavior of the optical path difference is analytically established by incorporating the contribution of the surface viscosity. [ABSTRACT FROM AUTHOR]

Objectives: A single value of tumor marker elevation is not used for the diagnosis of breast cancer (BC) relapse, whereas the serial measurements which confirm a persistent Ca15.3 increase can represent an early signal of tumor relapse, even if described in asymptomatic patients without any other clinical or instrumental signs of cancer. The aim of this study was to assess the relationship between serial measures of Ca15.3 and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings in patients with already treated BC during follow-up. Methods: We retrospectively selected 60 patients (mean age 62 ± 11 years) with previous history of BC, already treated with surgery and other treatments. Three serial measures of Ca15.3 were collected within 1 year before PET/CT examination, respectively, at 12-9 months (297 ± 30 days), 9-3 months (154 ± 51 days) and 3-0 months (46 ± 28 days). Clinical outcome or imaging follow-up data were used to define disease relapse. The increase in tumor marker value was compared with PET/CT results and disease relapse. Coefficient of variation (CV) and ROC curves were used. Disease-free survival (DFS) curves were computed by Kaplan-Meier method. Results: PET/CT was negative in 36 (60%) and positive in 24 (40%) patients. The median time between initial treatment and PET/CT was 3 years. CV of the Ca15.3 serial determinations was significantly higher in patients with positive than negative PET/CT (39 vs. 24%, p < 0.05). Disease relapse was found in 25 (42%) patients, of these 21 (88%) had positive PET/CT. ROC analyses showed that an increase of Ca15.3 between the 2nd and 3rd measures have better individuated positive PET/CT and disease relapse (AUC 0.65 and 0.64, respectively; p < 0.05). DFS was higher in patients with negative than positive PET/CT (65 vs. 15%, p < 0.05). Conclusions: Serial increase of Ca15.3 could be considered optimal to address FDG PET/CT examination during BC patients follow-up. PET/CT performed just on time might allow, earlier and with higher diagnostic accuracy, the detection of disease relapse in BC patients. [ABSTRACT FROM AUTHOR]

We obtain an exact form for the propagator of the Fokker-Planck equation ∂tρ = [formula] -∂x(F(x, t)ρ), with D(x)=D|x|-η in presence of the external force F(x,t)=-k(t)x+K/x|x|-η. Using the results found here, we also investigate the mean square displacement, survival probability, and first passage time distribution. In addition, we discuss the connection of these results with anomalous diffusion phenomena. [ABSTRACT FROM AUTHOR]

Abstract: Aims: To describe the levels and identify independent predictors of caregiver burden in partners of patients with heart failure. Background: Care and support from a partner are important for the well-being of patients with heart failure and may potentially delay disease progression. However, caregiving may be associated with burden and stress and it is therefore important to understand which factors that influence caregiver burden. Theoretical models of caregiving describe the concept of burden as an outcome variable, including decreased well-being and health. Methods: Data for this descriptive cross-sectional study were collected between January 2005 and September 2008. The dependent variable consisted of the Caregiver Burden Scale total score index. Socio-demographic and clinical characteristics, health-related quality of life, symptoms of depression, perceived control, and knowledge on heart failure were included in a regression analysis to determine independent predictors of caregiver burden. Results: The 135 partners had a mean-age of 69years and 75% were females. Caregiver burden was perceived as medium in 30% of the partners. The patients'' Physical Component Score of SF-36 (p <0.001), partners'' Mental Component Score of SF-36 (p <0.001) and perceived control (p <0.01) accounted for 39% of the variance in caregiver burden. Conclusion: Caregiver burden was lower when the mental health of the partner and the physical health of the patient were better and the partner experienced higher control over the heart disease. A partner-centered approach to educate and support partners of patients with heart failure is essential to improve the life situation for patient–partner dyads. [ABSTRACT FROM AUTHOR]

The molecular orientation of a nematic sample limited by two concentric cylinders is theoretically investigated. The surfaces are assumed as having an inhomogeneous distribution of easy directions. The results are found in the one-constant approximation, in the presence of an external electric field, for weak anchoring of the molecules at the surfaces. In order to validate our approximations, the analytical results are compared with the ones obtained by numerically solving the non-linear bulk differential equation for the tilt angle profile subjected to non-linearized boundary conditions. We show that the agreement improves as the extrapolation length increases. [ABSTRACT FROM AUTHOR]

The authors reflect on the importance of nuclear medicine and the evolution of the modern management of castration-resistant prostate cancer patients. They cite the profound involvement of nuclear medicine in detecting prostate cancer (PC) including the increased use of radiopharmaceutical agents and beta-emitting agents. Also emphasized are the various radiopharmaceutical options in detecting the metastatic PC.

Background Reduced systolic reserve on effort may be present in subjects with hypertension but no evidence of hypertensive cardiomyopathy. We assessed the determinants of abnormal cardiac performance during exercise in hypertensive patients without left ventricular hypertrophy. Materials and methods Thirty-five newly diagnosed, never-treated-earlier hypertensive patients without definite indication for left ventricular hypertrophy at echocardiography underwent radionuclide ambulatory monitoring of left ventricular function at rest and during upright bicycle exercise testing. Results The patients were classified into two groups according to their ejection fraction response to exercise. In 21 patients (group 1), the ejection fraction increased ≥ 5% with exercise and in 14 patients (group 2), the ejection fraction either increased < 5% or decreased with exercise. Patients of group 1 had lower peak filling rate at rest and less augmentation in end-diastolic volume during exercise (both P < 0·01) when compared with patients of group 2. A significant relationship between the magnitude of change in ejection fraction with exercise and both peak filling rate at rest ( r = 0·58, P < 0·01) and exercise-induced change in end-diastolic volume ( r = 0·45, P < 0·01) was found. Conclusions In newly diagnosed, never-treated-earlier hypertensive subjects with no evidence of hypertensive cardiomyopathy, the cardiac response to exercise is dependent on adequate diastolic filling volume to maintain systolic performance. [ABSTRACT FROM AUTHOR]

Objective: The potential adverse effects of antiretroviral drugs during pregnancy are discrepant and few studies, mostly from Europe, have provided information about pregnancy outcomes of those already on treatment at conception. The aim of this study was to investigate the impact of antiretrovirals (ARVs) on pregnancy outcome according to the timing of treatment initiation in a cohort of pregnant women from Brazil infected with HIV.Methods: A prospective cohort of 696 pregnant women followed up in one single centre between 1996 and 2006 was studied. Patients who had ARV treatment before pregnancy were compared with those treated after the first trimester. The outcomes evaluated were preterm delivery (PTD) (<37 weeks), severe PTD (<34 weeks), low birth weight (LBW) (<2500 g) and very LBW (<1500 g).Results: Patients who were using ARVs pre-conception had higher rates of LBW (33.3% vs 16.5%; p<0.001) and a similar trend for PTD (26.3% vs 17.7%; p = 0.09). Stratification by type of therapy (dual vs highly active antiretroviral therapy (HAART)) according to timing of initiation of ARVs showed that patients who use HAART pre-conception have a higher rate of PTD (20.2% vs 10.2%; p = 0.03) and LBW (24.2% vs 10.2%; p = 0.002). After adjusting for several factors, HAART used pre-conception was associated with an increased risk for PTD (AOR 5.0; 95% CI 1.5 to 17.0; p = 0.009) and LBW (OR 3.6; 95% CI 1.7 to 7.7; p = 0.001).Conclusions: We identified an increased risk for LBW and PTD in patients who had HAART prior to pregnancy. [ABSTRACT FROM AUTHOR]

Genetic variations in catechol- O-methyl transferase (COMT) or administration of COMT inhibitors have a robust impact on cognition and executive function in humans. The COMT enzyme breaks down extracellular dopamine (DA) and has a particularly important role in the prefrontal cortex (PFC) where DA transporters are sparse. As such, the beneficial cognitive effects of the COMT inhibitor tolcapone are postulated to be the result of increased bioavailability of DA in the PFC. Furthermore, it has been shown previously that COMT inhibitors increase pharmacologically evoked DA but do not affect basal levels in the PFC. The current study characterized the ability of tolcapone to increase DA release in response to behaviorally salient stimuli and improve performance of the delayed spatial win-shift (DSWSh) task. Tolcapone enhanced PFC DA efflux associated with the anticipation and consumption of food when compared to saline controls. Chronic and acute treatment with tolcapone also reduced the number of errors committed during acquisition of the DSWSh. However, no dissociable effects were observed in experiments designed to selectively assay encoding or recall in well-trained animals, as both experiments showed improvement with tolcapone treatment. Taken together, these data suggest a generalized positive influence on cognition. Furthermore, these data support the conclusion of Apud and Weinberger (CNS Drugs 21:535–557, ) that agents which selectively potentiate PFC DA release may confer cognitive enhancement without the unwanted side effects produced by drugs that increase basal DA levels in cortical and subcortical brain regions. [ABSTRACT FROM AUTHOR]

The objective of this study was to describe the adherence to antiretroviral therapy (ART) among adolescents followed-up in Rio de Janeiro. This cross-sectional study included all adolescents (aged 10-19 years) followed at Instituto de Puericultura e Pediatria Martagão Gesteira and Hospital Universitário Clementino Fraga Filho. Adherence was determined by selfreport (number of missed ART doses in three days prior to the interview). Adherence was categorized as taking ⩾95% of the ARTs (adherent), or <95% (non-adherent). Variables related to demographics and treatment were evaluated and if P value ⩽0.15, they were selected for a logistic regression analysis. One hundred and one adolescents were interviewed. The mean time on ART was 91 months and the mean adherence was 94% of this, 21 were non-adherent, and 80 adherent. The risk factors associated with non-adherence were: if the patient was not concerned about ART, odds ratio (OR) = 3.47 (95% confidence interval [CI] = 1.13- 10.68); if they do not carry an extra dose of ART, OR = 6.63 (95% CI = 1.73-25.47); if a health-care worker taught them how to take ART, OR = 0.27 (95% CI = 0.08-0.93). Adherence among adolescents was higher than expected. Factors associated with lack of adherence were: interviewees being unaware of ARTs and lack of commitment to the treatment. Interventions involving these factors must be evaluated. [ABSTRACT FROM AUTHOR]

We consider nonlocal effects, obtained by incorporating fractional derivatives in the kinetic energy of a conventional Hamiltonian, to analyze physical properties of non-crystalline solids at very low temperature. By using thermal Green functions, we deduce some experimentally observable quantities such as the particle momentum distribution function, the particle energy distribution function, and the specific heat. The agreement between the results obtained for the specific heat and the experimental data suggests that the approach presented here may be useful as a phenomenological model to investigate thermal properties of non-crystalline solids at low temperature. [ABSTRACT FROM AUTHOR]