Determination of sulfate in ethanol fuel using an electrode chemically modified with polypyrrole by flow injection analysis

In this work, an electrode chemically modified with polypyrrole (PCME) was employed for determination of sulfate in ethanol fuel using a FIA system. The PCME was prepared by polymerization of pyrrole at a glassy carbon electrode by means of cyclic voltammetry technique. An analytical curve from 1.0 x 10−5 to 8.0 x 10−5 mol L−1 was obtained in flow injection system based on the PCME. An amperometric sensibility of 2.3 x 10−3 A mol−1 L and a detection limit of 2.5 x 10−6 mol L−1 were achieved. The proposed method was employed for determination of sulfate ions in commercial samples of ethanol fuel. The results were in good agreement with those obtained by the ionic chromatographic method.

Interior-exterior point method with global convergence strategy for solving the reactive optimal power flow problem

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Urinary flow in children: correlation with age, body height and body surface area

Peak flow rate data (Qmax) are important for diagnosis of lower urinary tract obstruction. However, the lack of uroflowmetry studies in children, makes their interpretation difficult. With this aim, we studied 167 boys classified in four groups according to their age (G1: n = 48, 6-7 years; G2: n = 43, 8-9 years; G3: n = 37, 10-11 years; G4: n = 39, 12-14 years). We studied in all children, weight, height, body surface area, peak flow rate (Qmax) and the correspondant urinary volume (Vol). Means and standard deviations of Qmax (ml/sec) were: 15 +/- 5 (G1), 15 +/- 5 (G2), 17 +/- 5 (G3) and 22 +/- 7 (G4) respectively. Corresponding urinary volumes (Vol) (mean standard deviation-in ml) were: G1 = 123 +/- 75; G2 = 122 +/- 79; G3 = 158 +/- 96 and G4 = 162 +/- 101. We found a significant correlation (p < 0,01) between Qmax and Vol in groups G2, G3 and G4; and between Qmax and height in groups G1 and G4. The authors demonstrated a positive correlation between maximum flow and voided volume, and an increase of Qmax with age.

Approximation Algorithms for Survivable Multicommodity Flow Problems with Applications to Network Design

Multicommodity flow (MF) problems have a wide variety of applications in areas such as VLSI circuit design, network design, etc., and are therefore very well studied. The fractional MF problems are polynomial time solvable while integer versions are NP-complete. However, exact algorithms to solve the fractional MF problems have high computational complexity. Therefore approximation algorithms to solve the fractional MF problems have been explored in the literature to reduce their computational complexity. Using these approximation algorithms and the randomized rounding technique, polynomial time approximation algorithms have been explored in the literature. In the design of high-speed networks, such as optical wavelength division multiplexing (WDM) networks, providing survivability carries great significance. Survivability is the ability of the network to recover from failures. It further increases the complexity of network design and presents network designers with more formidable challenges. In this work we formulate the survivable versions of the MF problems. We build approximation algorithms for the survivable multicommodity flow (SMF) problems based on the framework of the approximation algorithms for the MF problems presented in [1] and [2]. We discuss applications of the SMF problems to solve survivable routing in capacitated networks.

Percolated non-Newtonian flow for silicone obtained from exfoliated bioinorganic layered double hydroxide intercalated with amino acid

A simple and scalable procedure was used to obtain thin, stable, homogeneous, and easy-to-handle films composed of silicone derived from dimethicones containing dispersed hydrotalcite-type materials previously organo-modified with amino acids. The absence of the typical X-ray pattern of the bioinorganic LDH filler suggested an exfoliation process that was further indirectly evidenced by a drastic change in the rheological behavior, which turned from a quasi-Newtonian behavior for the silicone free of LDH filler to an extensive developed gel-like structure for the nanocomposite derivatives. Visualized by the shear-thinning exponent of the complex viscosity in the low-frequency range, the percolation threshold was evident for filler loading as low as <5 w/W%, suggesting the presence of a largely developed interface between the filler and the polymer. The increase of more than one order of magnitude in viscosity was explained by the rather strong attrition phenomenon between the tethered amino acid anions and the silicone chains. UVB radiation absorption profiles make such bioinorganic polymer nanocomposites potentially applicable in skin protection. Thermo-gravimetric analysis revealed significant improvement in the thermal stability, especially in the final step of the polymer combustion, thus underlining the role of the hybrid material as a thermal retardant agent. (C) 2011 Elsevier B.V. All rights reserved.

Directed and elliptic flow of charged particles in Cu plus Cu collisions at root s(NN)=22.4 GeV

This paper reports results for directed flow v(1) and elliptic flow v(2) of charged particles in Cu + Cu collisions at root s(NN) = 22.4 GeV at the Relativistic Heavy Ion Collider. The measurements are for the 0-60% most central collisions, using charged particles observed in the STAR detector. Our measurements extend to 22.4-GeV Cu + Cu collisions the prior observation that v1 is independent of the system size at 62.4 and 200 GeV and also extend the scaling of v(1) with eta/y(beam) to this system. The measured v(2)(p(T)) in Cu + Cu collisions is similar for root s(NN) throughout the range 22.4 to 200 GeV. We also report a comparison with results from transport model (ultrarelativistic quantum molecular dynamics and multiphase transport model) calculations. The model results do not agree quantitatively with the measured v(1)(eta), v(2)(p(T)), and v(2)(eta).

Strength Training with Blood Flow Restriction Diminishes Myostatin Gene Expression

LAURENTINO, G. C., C. UGRINOWITSCH, H. ROSCHEL, M. S. AOKI, A. G. SOARES, M. NEVES JR, A. Y. AIHARA, A. DA ROCHA CORREA FERNANDES, and V. TRICOLI. Strength Training with Blood Flow Restriction Diminishes Myostatin Gene Expression. Med. Sci. Sports Exerc., Vol. 44, No. 3, pp. 406-412, 2012. Purpose: The aim of the study was to determine whether the similar muscle strength and hypertrophy responses observed after either low-intensity resistance exercise associated with moderate blood flow restriction or high-intensity resistance exercise are associated with similar changes in messenger RNA (mRNA) expression of selected genes involved in myostatin (MSTN) signaling. Methods: Twenty-nine physically active male subjects were divided into three groups: low-intensity (20% one-repetition maximum (1RM)) resistance training (LI) (n = 10), low-intensity resistance exercise associated with moderate blood flow restriction (LIR) (n = 10), and high-intensity (80% 1RM) resistance exercise (HI) (n = 9). All of the groups underwent an 8-wk training program. Maximal dynamic knee extension strength (1RM), quadriceps cross-sectional area (CSA), MSTN, follistatin-like related genes (follistatin (FLST), follistatin-like 3 (FLST-3)), activin IIb, growth and differentiation factor-associated serum protein 1 (GASP-1), and MAD-related protein (SMAD-7) mRNA gene expression were assessed before and after training. Results: Knee extension 1RM significantly increased in all groups (LI = 20.7%, LIR = 40.1%, and HI = 36.2%). CSA increased in both the LIR and HI groups (6.3% and 6.1%, respectively). MSTN mRNA expression decreased in the LIR and HI groups (45% and 41%, respectively). There were no significant changes in activin IIb (P > 0.05). FLST and FLST-3 mRNA expression increased in all groups from pre- to posttest (P < 0.001). FLST-3 expression was significantly greater in the HI when compared with the LIR and LI groups at posttest (P = 0.024 and P = 0.018, respectively). GASP-1 and SMAD-7 gene expression significantly increased in both the LIR and HI groups. Conclusions: We concluded that LIR was able to induce gains in 1RM and quadriceps CSA similar to those observed after traditional HI. These responses may be related to the concomitant decrease in MSTN and increase in FLST isoforms, GASP-1, and SMAD-7 mRNA gene expression.

Abnormal resting state corticolimbic blood flow in depressed unmedicated patients with major depression: A 15O-H2O PET study

We investigated the differences in the resting state corticolimbic blood flow between 20 unmedicated depressed patients and 21 healthy comparisons. Resting state cerebral blood flow (CBF) was measured with H215O PET. Anatomical MRI scans were performed on an Elscint 1.9 T Prestige system for PET-MRI coregistration. Significant changes in cerebral blood flow indicating neural activity were detected using an ROI-free image subtraction strategy. In addition, the resting blood flow in patients was correlated with the severity of depression as measured by HAM-D scores. Depressed patients showed decreases in blood flow in right anterior cingulate (Brodmann areas 24 and 32) and increased blood flow in left and right posterior cingulate (Brodmann areas 23, 29, 30), left parahippocampal gyrus (Brodmann area 36), and right caudate compared with healthy volunteers. The severity of depression was inversely correlated with the left middle and inferior frontal gyri (Brodmann areas 9 and 47) and right medial frontal gyrus (Brodmann area 10) and right anterior cingulate (Brodmann areas 24, 32) blood flow, and directly correlated with the right thalamus blood flow. These findings support previous reports of abnormalities in the resting state blood flow in the limbic-frontal structures in depressed patients compared to healthy volunteers. Hum Brain Mapp, 2012. (C) 2011 Wiley Periodicals, Inc.

Flow Visualization with Quantified Spatial and Temporal Errors Using Edge Maps

Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Traditional analysis and visualization techniques rely primarily on computing streamlines through numerical integration. The inherent numerical errors of such approaches are usually ignored, leading to inconsistencies that cause unreliable visualizations and can ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with maps from the triangle boundaries to themselves. This representation, called edge maps, permits a concise description of flow behaviors and is equivalent to computing all possible streamlines at a user defined error threshold. Independent of this error streamlines computed using edge maps are guaranteed to be consistent up to floating point precision, enabling the stable extraction of features such as the topological skeleton. Furthermore, our representation explicitly stores spatial and temporal errors which we use to produce more informative visualizations. This work describes the construction of edge maps, the error quantification, and a refinement procedure to adhere to a user defined error bound. Finally, we introduce new visualizations using the additional information provided by edge maps to indicate the uncertainty involved in computing streamlines and topological structures.

A modified Primal-Dual Logarithmic-Barrier Method for solving the Optimal Power Flow problem with discrete and continuous control variables

The aim of solving the Optimal Power Flow problem is to determine the optimal state of an electric power transmission system, that is, the voltage magnitude and phase angles and the tap ratios of the transformers that optimize the performance of a given system, while satisfying its physical and operating constraints. The Optimal Power Flow problem is modeled as a large-scale mixed-discrete nonlinear programming problem. This paper proposes a method for handling the discrete variables of the Optimal Power Flow problem. A penalty function is presented. Due to the inclusion of the penalty function into the objective function, a sequence of nonlinear programming problems with only continuous variables is obtained and the solutions of these problems converge to a solution of the mixed problem. The obtained nonlinear programming problems are solved by a Primal-Dual Logarithmic-Barrier Method. Numerical tests using the IEEE 14, 30, 118 and 300-Bus test systems indicate that the method is efficient. (C) 2012 Elsevier B.V. All rights reserved.

Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus

OBJECTIVE: To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes. METHODS: A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA(1) levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter. RESULTS: Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery. CONCLUSIONS: Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.

A new evolutionary clustering search for a no-wait flow shop problem with set-up times

This paper addresses the m-machine no-wait flow shop problem where the set-up time of a job is separated from its processing time. The performance measure considered is the total flowtime. A new hybrid metaheuristic Genetic Algorithm-Cluster Search is proposed to solve the scheduling problem. The performance of the proposed method is evaluated and the results are compared with the best method reported in the literature. Experimental tests show superiority of the new method for the test problems set, regarding the solution quality. (c) 2012 Elsevier Ltd. All rights reserved.

Muscle blood flow is reduced with dehydration during prolonged exercise in humans

[EN] 1. The present study examined whether the blood flow to exercising muscles becomes reduced when cardiac output and systemic vascular conductance decline with dehydration during prolonged exercise in the heat. A secondary aim was to determine whether the upward drift in oxygen consumption (VO2) during prolonged exercise is confined to the active muscles. 2. Seven euhydrated, endurance-trained cyclists performed two bicycle exercise trials in the heat (35 C; 40-50 % relative humidity; 61 +/- 2 % of maximal VO2), separated by 1 week. During the first trial (dehydration trial, DE), they bicycled until volitional exhaustion (135 +/- 4 min, mean +/- s.e.m.), while developing progressive dehydration and hyperthermia (3.9 +/- 0.3 % body weight loss; 39.7 +/- 0.2 C oesophageal temperature, Toes). In the second trial (control trial), they bicycled for the same period of time while maintaining euhydration by ingesting fluids and stabilizing Toes at 38.2 +/- 0.1 C after 30 min exercise. 3. In both trials, cardiac output, leg blood flow (LBF), vascular conductance and VO2 were similar after 20 min exercise. During the 20 min-exhaustion period of DE, cardiac output, LBF and systemic vascular conductance declined significantly (8-14 %; P < 0.05) yet muscle vascular conductance was unaltered. In contrast, during the same period of control, all these cardiovascular variables tended to increase. After 135 +/- 4 min of DE, the 2.0 +/- 0.6 l min-1 lower blood flow to the exercising legs accounted for approximately two-thirds of the reduction in cardiac output. Blood flow to the skin also declined markedly as forearm blood flow was 39 +/- 8 % (P < 0.05) lower in DE vs. control after 135 +/- 4 min. 4. In both trials, whole body VO2 and leg VO2 increased in parallel and were similar throughout exercise. The reduced leg blood flow in DE was accompanied by an even greater increase in femoral arterial-venous O2 (a-vO2) difference. 5. It is concluded that blood flow to the exercising muscles declines significantly with dehydration, due to a lowering in perfusion pressure and systemic blood flow rather than increased vasoconstriction. Furthermore, the progressive increase in oxygen consumption during exercise is confined to the exercising skeletal muscles.

Optical flow estimation with consistent spatio-temporal coherence models

[EN] In this work we propose a new variational model for the consistent estimation of motion fields. The aim of this work is to develop appropriate spatio-temporal coherence models. In this sense, we propose two main contributions: a nonlinear flow constancy assumption, similar in spirit to the nonlinear brightness constancy assumption, which conveniently relates flow fields at different time instants; and a nonlinear temporal regularization scheme, which complements the spatial regularization and can cope with piecewise continuous motion fields. These contributions pose a congruent variational model since all the energy terms, except the spatial regularization, are based on nonlinear warpings of the flow field. This model is more general than its spatial counterpart, provides more accurate solutions and preserves the continuity of optical flows in time. In the experimental results, we show that the method attains better results and, in particular, it considerably improves the accuracy in the presence of large displacements.

Reliable estimation of dense optical flow fields with large displacements

[EN] In this paper we show that a classic optical flow technique by Nagel and Enkelmann can be regarded as an early anisotropic diffusion method with a diffusion tensor. We introduce three improvements into the model formulation that avoid inconsistencies caused by centering the brightness term and the smoothness term in different images use a linear scale-space focusing strategy from coarse to fine scales for avoiding convergence to physically irrelevant local minima, and create an energy functional that is invariant under linear brightness changes.  Applying a gradient descent method to the resulting energy functional leads to a system of diffusion-reaction equations. We prove that this system has a unique solution under realistic assumptions on the initial data, and we present an efficient linear implicit numerical scheme in detail. Our method creates flow fields with 100% density over the entire image domain, it is robust under a large range of parameter variations, and it can recover displacement fields that are far beyond the typical one-pixel limits which are characteristic for many differential methods for determining optical flow. We show that it performs better than the classic optical flow methods with 100%  density that are evaluated by Barron et al. (1994). Our software is available from the Internet.