Influence of kaolin and red clay on ceramic specimen properties when galvanic sludge is incorporated to encapsulate heavy metals.

This study presented the influence of two types of clay: kaolin (Kao) and red clay (RC) on the chemical and physical properties of ceramic specimens when galvanic sludge (GS) is incorporated to encapsulate heavy metals. Samples were obtained of GS from the industrial district of Manaus - Amazonas State, Brazil, and kaolin (Kao), and red clay (RC) from the Central Amazon. A fourth sample was prepared by mixing GS, Kao, and RC in the ratio 1:1:8 (GS + Kao + RC). This mixture was ground, and ceramic specimens were prepared, and heat treated at 950 °C and 1200 °C for three hours for phase detection, compressive strength, leaching of Fe, Ni and Cr metals and life cycle assessment. Galvanic sludge, Kao, and RC were also, and heat treated to at 950 °C and 1200 °C for three hours, obtaining GS950, GS1200, Kao950, Kao1200, RC950, and RC1200. The samples were submitted to XRF, XRD, Rietveld refinement, Mössbauer spectroscopy, TG/DTG/DSC, and SEM. The results show that the formation of nickel oxide and a spinel solid solution of the type Fe3+{Fe1-y3+,Fe1-x2+,Nix2+,Cry3+}O4 (in which [] = tetrahedral site, {} octahedral site) occurs in GS1200, which is caused by sulfate decomposition to SO2. At 1200 °C, heavy metals are encapsulated, forming other phases such as nickel silicate and hematite. Life cycle assessment was used to verify the sustainability and value of GS in clay for making bricks, and it indicated that the production of ceramics is feasible, reduces the use of clays, and is sustainable.

Copper molybdate synthesized by sonochemistry route at room temperature as an efficient solid catalyst for esterification of oleic acid.

Copper molybdate nanoplates were synthesized by a sonochemical process at room temperature, which we report as a simple and cost-effective route. Structural analysis of the material by the Rietveld method of X-ray diffraction (XRD) data revealed lindgrenite Cu3(MoO4)2(OH)2 in a single-phase structure. All the vibrational modes characteristic of the space group were identified by Raman vibrational and near-infrared (NIR) spectroscopies. The profile obtained for N2 adsorption/desorption was type III hysteresis, characteristic of mesoporous materials, with a surface area of 70.77(1) m2 g-1. The micrographs of the material obtained by scanning electron microscopy showed nanoplates with nanometric sizes and an anisotropic growth aspect. The catalytic activity of lindgrenite was evaluated by esterifying oleic acid with methanol, showing high conversion rate to methyl oleate and good catalyst stability after seven recycling cycles. Above all, the best catalytic performance was reached when we optimized parameters such as oleic acid:methanol molar ratio of 1:5, 5% of catalyst dosage, and reaction time of 5 h, resulting in 98.38% of conversion at 413 K. Therefore, sonochemically synthesized lindgrenite proved to be a high potential material for biofuel production by oleic acid esterification.

Multispecies effects in the equilibrium and out-of-equilibrium thermostatistics of overdamped motion.

Progress has been recently made, both theoretical and experimental, regarding the thermostatistics of complex systems of interacting particles or agents (species) obeying a nonlinear Fokker-Planck dynamics. However, major advances along these lines have been restricted to systems consisting of only one type of species. The aim of the present contribution is to overcome that limitation, going beyond single-species scenarios. We investigate the dynamics of overdamped motion in interacting and confined many-body systems having two or more species that experience different intra- and interspecific forces in a regime where forces arising from standard thermal noise can be neglected. Even though these forces are neglected, the behavior of the system can be analyzed in terms of an appropriate thermostatistical formalism. By recourse to a mean-field treatment, we derive a set of coupled nonlinear Fokker-Planck equations governing the behavior of these systems. We obtain an H theorem for this Fokker-Planck dynamics and discuss in detail an example admitting an exact, analytical stationary solution.

Nonlinear drag forces and the thermostatistics of overdamped motion.

Diverse processes in statistical physics are usually analyzed on the assumption that the drag force acting on a test particle moving in a resisting medium is linear on the velocity of the particle. However, nonlinear drag forces do appear in relevant situations that are currently the focus of experimental and theoretical work. Motivated by these developments, we explore the consequences of nonlinear drag forces for the thermostatistics of systems of interacting particles performing overdamped motion. We derive a family of nonlinear Fokker-Planck equations for these systems, taking into account the effects of nonlinear drag forces. We investigate the main properties of these evolution equations, including an H-theorem, and obtain exact solutions of the stretched q-exponential form.

From the nonlinear Fokker-Planck equation to the Vlasov description and back: Confined interacting particles with drag.

Nonlinear Fokker-Planck equations endowed with power-law diffusion terms have proven to be valuable tools for the study of diverse complex systems in physics, biology, and other fields. The nonlinearity appearing in these evolution equations can be interpreted as providing an effective description of a system of particles interacting via short-range forces while performing overdamped motion under the effect of an external confining potential. This point of view has been recently applied to the study of thermodynamical features of interacting vortices in type II superconductors. In the present work we explore an embedding of the nonlinear Fokker-Planck equation within a Vlasov equation, thus incorporating inertial effects to the concomitant particle dynamics. Exact time-dependent solutions of the q-Gaussian form (with compact support) are obtained for the Vlasov equation in the case of quadratic confining potentials.

Prospective evaluation of Streptococcus pneumoniae serum antibodies in patients with primary immunodeficiency on regular intravenous immunoglobulin treatment.

BACKGROUND: This is a prospective study that assessed pneumococcal antibody levels in PID patients under intravenous immunoglobulin (IVIG) treatment using different brands. METHODS: Twenty-one patients receiving regular IVIG every 28 days were invited to participate: 12 with common variable immunodeficiency, six with X-linked agammaglobulinaemia and three with hyper-IgM syndrome. One blood sample was collected from each patient just prior to IVIG administration at a three-month time interval during one year. A questionnaire was filled in with patient's demographic data and history of infections during the study period. Streptococcus pneumoniae antibodies against six serotypes (1, 5, 6B, 9V, 14 and 19F) were assessed by ELISA both in patients' serum (trough levels) and in IVIG samples. RESULTS: Median total IgG trough serum levels were 7.91g/L (range, 4.59-12.20). All patients had antibody levels above 0.35µg/mL to the six serotypes on all four measurements. However, only 28.6% of patients had pneumococcal antibodies for the six analysed serotypes above 1.3µg/mL on all four evaluations during the one-year period. No correlation was found between IgG trough levels and pneumococcal specific antibodies. Eighteen of the 21 patients (85.7%) had infections at some point during the 12-month follow-up, 62/64 (96.9%) clinically classified in respiratory tract infections, four of which were pneumonia. CONCLUSIONS: Pneumococcal antibodies are present in a high range of concentrations in sera from PID patients and also in IVIG preparations. Even maintaining a recommended IgG trough level, these patients can be susceptible to these bacteria and that may contribute to recurrent respiratory infections.

Nonlinear Kramers equation associated with nonextensive statistical mechanics.

Stationary and time-dependent solutions of a nonlinear Kramers equation, as well as its associated nonlinear Fokker-Planck equations, are investigated within the context of Tsallis nonextensive statistical mechanics. Since no general analytical time-dependent solutions are found for such a nonlinear Kramers equation, an ansatz is considered and the corresponding asymptotic behavior is studied and compared with those known for the standard linear Kramers equation. The H-theorem is analyzed for this equation and its connection with Tsallis entropy is investigated. An application is discussed, namely the motion of Hydra cells in two-dimensional cellular aggregates, for which previous measurements have verified q-Gaussian distributions for velocity components and superdiffusion. The present analysis is in quantitative agreement with these experimental results.

Nonlinear Ehrenfest's urn model.

Ehrenfest's urn model is modified by introducing nonlinear terms in the associated transition probabilities. It is shown that these modifications lead, in the continuous limit, to a Fokker-Planck equation characterized by two competing diffusion terms, namely, the usual linear one and a nonlinear diffusion term typical of anomalous diffusion. By considering a generalized H theorem, the associated entropy is calculated, resulting in a sum of Boltzmann-Gibbs and Tsallis entropic forms. It is shown that the stationary state of the associated Fokker-Planck equation satisfies precisely the same equation obtained by extremization of the entropy. Moreover, the effects of the nonlinear contributions on the entropy production phenomenon are also analyzed.

Doctors' awareness concerning primary immunodeficiencies in Brazil.

BACKGROUND: PIDs are a heterogeneous group of genetic illnesses, and delay in their diagnosis is thought to be caused by a lack of awareness among physicians concerning PIDs. The latter is what we aimed to evaluate in Brazil. METHODS: Physicians working at general hospitals all over the country were asked to complete a 14-item questionnaire. One of the questions described 25 clinical situations that could be associated with PIDs and a score was created based on percentages of appropriate answers. RESULTS: A total of 4026 physicians participated in the study: 1628 paediatricians (40.4%), 1436 clinicians (35.7%), and 962 surgeons (23.9%). About 67% of the physicians had learned about PIDs in medical school or residency training, 84.6% evaluated patients who frequently took antibiotics, but only 40.3% of them participated in the immunological evaluation of these patients. Seventy-seven percent of the participating physicians were not familiar with the warning signs for PIDs. The mean score of correct answers for the 25 clinical situations was 48.08% (±16.06). Only 18.3% of the paediatricians, 7.4% of the clinicians, and 5.8% of the surgeons answered at least 2/3 of these situations appropriately. CONCLUSIONS: There is a lack of medical awareness concerning PIDs, even among paediatricians, who have been targeted with PID educational programmes in recent years in Brazil. An increase in awareness with regard to these disorders within the medical community is an important step towards improving recognition and treatment of PIDs.

Risk groups in children under six months of age using self-organizing maps.

Fetal and infant growth tends to follow irregular patterns and, particularly in developing countries, these patterns are greatly influenced by unfavorable living conditions and interactions with complications during pregnancy. The aim of this study was to identify groups of children with different risk profiles for growth development. The study sample comprised 496 girls and 508 boys under six months of age from 27 pediatric primary health care units in the city of Rio de Janeiro, Brazil. Data were obtained through interviews with the mothers and by reviewing each child's health card. An unsupervised learning, know as a self-organizing map (SOM) and a K-means algorithm were used for cluster analysis to identify groups of children. Four groups of infants were identified. The first (139) consisted of infants born exclusively by cesarean delivery, and their mothers were exclusively multiparous; the highest prevalences of prematurity and low birthweight, a high prevalence of exclusive breastfeeding and a low proportion of hospitalization were observed for this group. The second (247 infants) and the third (298 infants) groups had the best and worst perinatal and infant health indicators, respectively. The infants of the fourth group (318) were born heavier, had a low prevalence of exclusive breastfeeding, and had a higher rate of hospitalization. Using a SOM, it was possible to identify children with common features, although no differences between groups were found with respect to the adequacy of postnatal weight. Pregnant women and children with characteristics similar to those of group 3 require early intervention and more attention in public policy.

Generalized entropy production phenomena: a master-equation approach.

The time rate of generalized entropic forms, defined in terms of discrete probabilities following a master equation, is investigated. Both contributions, namely entropy production and flux, are obtained, extending works carried previously for the Boltzmann-Gibbs entropy to a wide class of entropic forms. Particularly, it is shown that the entropy-production contribution is always non-negative for such entropies. Some illustrative examples for known generalized entropic forms in the literature are also worked out. Since generalized entropies have been lately associated with several complex systems in nature, the present analysis should be applicable to irreversible processes in these systems.

Taxonomic assessment and enzymes production by yeasts isolated from marine and terrestrial Antarctic samples.

The aim of the present study was to investigate the taxonomic identity of yeasts isolated from the Antarctic continent and to evaluate their ability to produce enzymes (lipase, protease and xylanase) at low and moderate temperatures. A total of 97 yeast strains were recovered from marine and terrestrial samples collected in the Antarctica. The highest amount of yeast strains was obtained from marine sediments, followed by lichens, ornithogenic soils, sea stars, Salpa sp., algae, sea urchin, sea squirt, stone with lichens, Nacella concinna, sea sponge, sea isopod and sea snail. Data from polyphasic taxonomy revealed the presence of 21 yeast species, distributed in the phylum Ascomycota (n = 8) and Basidiomycota (n = 13). Representatives of encapsulated yeasts, belonging to genera Rhodotorula and Cryptococcus were recovered from 7 different Antarctic samples. Moreover, Candida glaebosa, Cryptococcus victoriae, Meyerozyma (Pichia) guilliermondii, Rhodotorula mucilaginosa and R. laryngis were the most abundant yeast species recovered. This is the first report of the occurrence of some species of yeasts recovered from Antarctic marine invertebrates. Additionally, results from enzymes production at low/moderate temperatures revealed that the Antarctic environment contains metabolically diverse cultivable yeasts, which could be considered as a target for biotechnological applications. Among the evaluated yeasts in the present study 46.39, 37.11 and 14.43 % were able to produce lipase (at 15 °C), xylanase (at 15 °C) and protease (at 25 °C), respectively. The majority of lipolytic, proteolytic and xylanolytic strains were distributed in the phylum Basidiomycota and were mainly recovered from sea stars, lichens, sea urchin and marine sediments.

Entropy production and nonlinear Fokker-Planck equations.

The entropy time rate of systems described by nonlinear Fokker-Planck equations--which are directly related to generalized entropic forms--is analyzed. Both entropy production, associated with irreversible processes, and entropy flux from the system to its surroundings are studied. Some examples of known generalized entropic forms are considered, and particularly, the flux and production of the Boltzmann-Gibbs entropy, obtained from the linear Fokker-Planck equation, are recovered as particular cases. Since nonlinear Fokker-Planck equations are appropriate for the dynamical behavior of several physical phenomena in nature, like many within the realm of complex systems, the present analysis should be applicable to irreversible processes in a large class of nonlinear systems, such as those described by Tsallis and Kaniadakis entropies.

Nonlinear relativistic and quantum equations with a common type of solution.

Generalizations of the three main equations of quantum physics, namely, the Schrödinger, Klein-Gordon, and Dirac equations, are proposed. Nonlinear terms, characterized by exponents depending on an index q, are considered in such a way that the standard linear equations are recovered in the limit q→1. Interestingly, these equations present a common, solitonlike, traveling solution, which is written in terms of the q-exponential function that naturally emerges within nonextensive statistical mechanics. In all cases, the well-known Einstein energy-momentum relation is preserved for arbitrary values of q.

Thermostatistics of overdamped motion of interacting particles.

We show through a nonlinear Fokker-Planck formalism, and confirm by molecular dynamics simulations, that the overdamped motion of interacting particles at T=0, where T is the temperature of a thermal bath connected to the system, can be directly associated with Tsallis thermostatistics. For sufficiently high values of T, the distribution of particles becomes Gaussian, so that the classical Boltzmann-Gibbs behavior is recovered. For intermediate temperatures of the thermal bath, the system displays a mixed behavior that follows a novel type of thermostatistics, where the entropy is given by a linear combination of Tsallis and Boltzmann-Gibbs entropies.

Comparison among probabilistic neural network, support vector machine and logistic regression for evaluating the effect of subthalamic stimulation in Parkinson disease on ground reaction force during gait.

Deep brain stimulation of the subthalamic nucleus (DBS-STN) is an approved treatment for advanced Parkinson disease (PD) patients; however, there is a need to further evaluate its effect on gait. This study compares logistic regression (LR), probabilistic neural network (PNN) and support vector machine (SVM) classifiers for discriminating between normal and PD subjects in assessing the effects of DBS-STN on ground reaction force (GRF) with and without medication. Gait analysis of 45 subjects (30 normal and 15 PD subjects who underwent bilateral DBS-STN) was performed. PD subjects were assessed under four test conditions: without treatment (mof-sof), with stimulation alone (mof-son), with medication alone (mon-sof), and with medication and stimulation (mon-son). Principal component (PC) analysis was applied to the three components of GRF separately, where six PC scores from vertical, one from anterior-posterior and one from medial-lateral were chosen by the broken stick test. Stepwise LR analysis employed the first two and fifth vertical PC scores as input variables. Using the bootstrap approach to compare model performances for classifying GRF patterns from normal and untreated PD subjects, the first three and the fifth vertical PCs were attained as SVM input variables, while the same ones plus the first anterior-posterior were selected as PNN input variables. PNN performed better than LR and SVM according to area under the receiver operating characteristic curve and the negative likelihood ratio. When evaluating treatment effects, the classifiers indicated that DBS-STN alone was more effective than medication alone, but the greatest improvements occurred with both treatments together.

Assessment of the effects of subthalamic stimulation in Parkinson disease patients by artificial neural network.

This study aims at using a probabilistic neural network (PNN) for discriminating between normal and Parkinson disease (PD) subjects using as input the principal components (PCs) derived from vertical component of the ground reaction force (vGRF). The trained PNN was further used for evaluating the effects of deep brain stimulation of the subthalamic nucleus (STN DBS) on PD, with and without medication. A sample of 45 subjects (30 normal and 15 PD subjects who underwent STN DBS) was evaluated by gait analysis. PD subjects were assessed under four test conditions: without treatment (mof-sof), only with stimulation (mof-son) or medication (mon-sof), and with combined treatments (mon-son). PC analysis was applied on vGRF, where six PC scores were chosen by the broken stick test. Using a bootstrap approach for the PNN model, and the area under the receiver operating characteristic curve (AUC) as performance measurement, the first three and fifth PCs were selected as input variables. The PNN presented AUC = 0.995 for classifying controls and PD subjects in the mof-sof condition. When applied to classify the PD subjects under treatment, the PNN indicated that STN DBS alone is more effective than medication, and further vGRF enhancement is obtained with combined therapies.

Salt and insulin sensitivity after short and prolonged high salt intake in elderly subjects.

Salt sensitivity and insulin resistance are correlated with higher cardiovascular risk. There is no information about changes in salt sensitivity (SS) and insulin sensitivity (IS) after a chronic salt overload in humans. The aim of this study was to evaluate these parameters in the elderly. Seventeen volunteers aged 70.5 +/- 5.9 years followed a low-salt diet (LSD) for 1 week and a high-salt diet (HSD) for 13 weeks. We evaluated SS after one week (HSD1) and after 13 weeks (HSD13), and subjects' IS and lipids on their usual diet (UD) at HSD1, and at HSD13. Blood pressure (BP) was measured at each visit and ambulatory blood pressure monitoring (ABPM) was performed twice. SS was the same at HSD1 and HSD13. Systolic BP was lower on LSD than on UD (P = 0.01), HSD1 (P < 0.01) and HSD13 (P < 0.01). When systolic and diastolic BP were evaluated by ABPM, they were higher at HSD13 during the 24-h period (P = 0.03 and P < 0.01) and during the wakefulness period (P = 0.02 and P < 0.01) compared to the UD. Total cholesterol was higher (P = 0.04) at HSD13 than at HSD1. Glucose and homeostasis model assessment (HOMA) were lower at HSD1 (P = 0.02 and P = 0.01) than at HSD13. Concluding, the extension of HSD did not change the SS in an elderly group. The higher IS found at HSD1 did not persist after a longer HSD. A chronic HSD increased BP as assessed by ABPM.