Genetics of idiopathic scoliosis

To define the luminal agent(s) responsible for the reduction of nephron filtration rate following increases of loop of Henle flow rate early proximal flow rate (EPFR) during loop perfusion with 17 different salt solutions were compared to the non-perfused tubules. During orthograde microperfusions a reduction of EPFR as indication of a feedback response was noted with a number of monovalent Cl- and Br- salts (LiCl, KCl, NaCl, RbCl, CsCl, NH4Cl, choline Cl, NaBr, KBr), with Na+ salts except Na acetate (NaHCO3, NaNO3, NaF, NaI, NaSCN), and with CaCl2 and MgCl2. These latter 2 solutions where used in a concentration of 70 mM while all other solutions had a concentration of 140 mM. During retrograde perfusion from the distal to the proximal end of the loop of Henle EPFR fell significantly with Cl- and Br- salts with percentage changes of EPFR ranging from -8.0 to -44.3%. In contrast, Cl- free salts and Cl- salts of divalent cations were associated with percentage changes of EPFR ranging from +7.1 to -6.2%, significance being reached only during perfusion with NaSCN. When furosemide (5 x 10(-4) M) was added to NaBr or KBr a feedback response was not observed. During orthograde perfusion with NaNO3 distal Cl- concentrations were 44.2 +/- 5.08, mM (mean +/- S.E.) at a perfusion rate of 10 nl/min and 59.1 +/- 3.93 mM at a rate of 40 nl/min. CaCl2 perfusion induced a marked elevation of distal Cl- concentrations to levels higher than 140 mM. Loop chloride handling was normal during RbCl perfusion. The magnitude of the feedback response during retrograde perfusion was not changed by lowering NaCl concentration from 140 to 60 mM, but fell when NaCl concentration was further reduced. In contrast to orthograde perfusions it was insensitive to changes in flow rate. Our results are compatible with the thesis that feedback responses depend critically upon the rate of Cl- transport probably across the macula densa cells. Br- ions can replace Cl- because they appear to share a common transport pathway which can be inhibited with furosemide. Unspecificity of feedback responses during orthograde microperfusions is due to presence of Cl- ions in the macula densa region even when solutions are initially Cl- free. Cl- salts of divalent cations do not elicit a feedback response because Cl- transport is severely curtailed.     

Graphite-epoxy composites for fuel-cell bipolar plates: Wet vs dry mixing and role of the design of experiment in the optimization of molding parameters

Bipolar plates (BPs) are key components of Proton Exchange Membrane Fuel Cells mainly employed in hydrogen-powered electric vehicles. Here, a reliable and detailed experimental method to prepare graphite-epoxy composites suitable for manufacturing BPs is reported. Dry and wet mixing procedures were compared and a simple composition was optimized, with regard to electrical conductivity. The adoption of wet mixing of the components and the choice of the conductive filler were the main factors that contributed to the achievement of good electrical and mechanical properties. The addition of a small percentage of carbon black as a secondary filler was also advantageous. The effects of molding parameters (pressure, temperature and time) on a fixed-composition graphite-epoxy composite were modeled using a Design Of Experiments approach, which provided valuable information for future improvements. Conductivity values well above the US DOE requirements were obtained.     

Establishment of radiation qualities for mammography according to the IEC 61267 and TRS 457

This article presents the technical conditions necessary to establish appropriate radiation qualities for the calibration of the dosemeters used in the mammography detectors in the Laboratório de Ciências Radiológicas (LCR) from the Universidade do Estado do Rio de Janeiro. Tests were conducted to evaluate the homogeneity of the radiation field, scattering, half-value layers and system stability. The calibration method (substitution) is described in this work. A moderate alteration in filtration makes it possible to maintain the half-value layers within the limits recommended. The results indicate the adequacy of the LCR laboratory for the calibration of the dosemeters in the radiation qualities for mammography with an expanded uncertainty in the best measurement capability of ± 1.8 % (k = 2).     

Extruded cylindrical strands: Mechanical properties correlated with the formation of biodegradable films through blown extrusion

The objective of this study was to determine the mechanical and viscoelastic properties of extruded cylindrical strands from biodegradable polymer blends and to verify the correlation of the blend properties with their capacity to form films in the blown extrusion process. The production of biodegradable films would only occur if the extruded strands showed adequate characteristics. The strands were produced by extrusion with blends containing starch, glycerol, and fatty acids (caproic, lauric, and stearic). These blends were compared with a standard formulation containing poly(butylene adipate‐co‐terephthalate) (PBAT), a biodegradable polymer. From the mechanical tension tests, the extruded strands containing fatty acids differed significantly from the standard one, it was not clear the possibility to establish a comparison between the mechanical properties of the extruded strands and the formation of films. The rheological tests indicated that the polymer blends presented the desired viscoelastic characteristics for the film formation by blown extrusion. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Carvacrol and 1,8-cineole alone or in combination at sublethal concentrations induce changes in the cell morphology and membrane permeability of Pseudomonas fluorescens in a vegetable-based broth

This study aimed to investigate the effects of sublethal concentrations of carvacrol (CAR) and 1,8-cineole (CIN) alone and in combination on the morphology, cell viability and membrane permeability of Pseudomonas fluorescens ATCC 11253 cultivated in a vegetable-based broth. Transmission and scanning electron microscopy images of bacterial cells exposed to CAR and CIN alone or in combination showed marked ultrastructural changes after 1h of exposure. These changes included shrunken protoplasm, discontinuity of the outer and cytoplasmic membranes and leakage of the intracellular material. Confocal scanning laser microscopy images corroborated the electron microscopy data, showing a decrease in the number of SYTO-9 cells (intact cells) with a concomitant increase in the number of PI-positive cells (dead cells). All of these morphological changes are indicative of increased membrane permeability and the loss of bacterial envelope integrity, which ultimately lead to cell death. The combination of sublethal concentrations of CAR and CIN could be applied to inhibit the growth of P. fluorescens on vegetables.     

Online hemodiafiltration: 4 years of clinical experience

Online hemodiafiltration (online HDF) is a new hemodialysis technique combining convection and diffusion and thus also enabling the purification of large molecules. As yet, only a small number of clinical experiences have been published about the effectiveness and safety of online HDF. We present a prospective and observational study conducted on 31 patients treated with online HDF in our center in the last 4 years. The purpose of the study is to compare the evolution of the following aspects before and after starting online HDF: dose of dialysis, purification of medium-sized/large molecules, inflammation, nutrition, Ca-P metabolism, anemia, and intradialytic complications. Online HDF increased Kt/V to 31.0% (p > 0.001) and reduced postdialysis beta(2)-M to 66.4% (p > 0.001). The rest of the parameters analyzed did not vary significantly. During online HDF, episodes of symptomatic hypotension fell by 45% in relation to conventional hemodialysis, and no relevant complication occurred. Online HDF is very useful in patients in whom we need to increase replacement therapy, such as patients with a large body surface, those in whom we suspect a residual syndrome or those who have been receiving dialysis for a long time and for whom we wish to prevent amyloidosis. Online HDF is safe and better tolerated than conventional hemodialysis.     

Effect of cigarette smoking on the bond strength between resin cement and dental CAD/CAM ceramics

Although the effects of cigarette smoking on several dental problems have been widely studied, the association between tobacco exposure and resin-ceramic bonding is rarely reported. This study investigated the resin-ceramic adhesion (shear bond strength, SBS) and associated risk factors on three selected dental CAD/CAM ceramics using a novel model to simulate the exposure to cigarette smoking. Specimens from IPS e.max® CAD, Vitabloc® Mark II for Cerec and Zirconia Cercon were prepared and treated using silicacoating and silane. A layer of resin cement was applied on the treated ceramic surfaces and light activated. Specimens were placed in a chamber and challenged with various numbers of cigarettes (0, 1, 5, 10, and 15). Then, the specimens were subjected to SBS test and fractured surfaces were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX) to determine the failure mode and surface composition. Overall, the mean SBS of IPS e.max^® CAD (9.6 ± 3.4 MPa), Vitabloc^® Mark II for Cerec (9.3 ± 2.5 MPa) and Zirconia Cercon (8.7 ± 3.0 MPa) did not show any statistical significant difference (p = 0.192 > 0.05), such that the adhesion of resin bonded to glass-based ceramics (IPS e.max® CAD and Vitabloc® Mark II for Cerec) decreased with cigarette smoke exposure, but increased for the resin bonded to zirconia ceramic (Zirconia Cercon). Furthermore, the number of cigarettes has a statistically significant effect on the SBS (p = 0.001), such that in general 5 cigarettes yielded the lowest mean SBS (7.6 ± 2.1 MPa). SEM-EDX analyses showed mostly adhesive failures in all experimental groups with changes in surface morphology and chemical composition after smoking challenge. Cigarette smoking produces a different effect on resin-ceramic bonding depending on ceramic type that may be due to chemical reactions in the bonding interface and changes in temperature and moisture. Further work should explore the mechanism to which cigarette smoke affects the resin-ceramic bonding and its clinical relevance.     

Pruning optimum-path forest ensembles using metaheuristic optimization for land-cover classification

Machine learning techniques have been actively pursued in the last years, mainly due to the increasing number of applications that make use of some sort of intelligent mechanism for decision-making processes. In this context, we shall highlight ensemble pruning strategies, which provide heuristics to select from a collection of classifiers the ones that can really improve recognition rates and provide efficiency by reducing the ensemble size prior to combining the model. In this article, we present and validate an ensemble pruning approach for Optimum-Path Forest (OPF) classifiers based on metaheuristic optimization over general-purpose data sets to validate the effectiveness and efficiency of the proposed approach using distinct configurations in real and synthetic benchmark data sets, and thereafter, we apply the proposed approach in remote-sensing images to investigate the behaviour of the OPF classifier using pruning strategies. The image data sets were obtained from CBERS-2B, LANDSAT-5 TM, IKONOS-2 MS, and GEOEYE sensors, covering some areas of Brazil. The well-known Indian Pines data set was also used. In this work, we evaluate five different optimization algorithms for ensemble pruning, including that Particle Swarm Optimization, Harmony Search, Cuckoo Search, and Firefly Algorithm. In addition, we performed an empirical comparison between Support Vector Machine and OPF using the strategy of ensemble pruning. Experimental results showed the effectiveness and efficiency of ensemble pruning using OPF-based classification, especially concerning ensemble pruning using Harmony Search, which shows to be effective without degrading the performance when applied to large data sets, as well as a good data generalization.     

Automation and intelligent scheduling of distributed system functional testing

International Journal on Software Tools for Technology Transfer - This paper presents the approach to functional test automation of services (black-box testing) and service architectures (grey-box...