Execution profiling blueprints

Although traditional approaches to code profiling help locate performance bottlenecks, they offer only limited support for removing these bottlenecks. The main reason is the lack of detailed visual runtime information to identify and eliminate computation redundancy. We provide three profiling blueprints that help identify and remove performance bottlenecks. The structural distribution blueprint graphically represents the CPU consumption share for each method and class of an application. The behavioral distribution blueprint depicts the distribution of CPU consumption along method invocations and hints at method candidates for caching optimizations. The behavioral evolution blueprint compares profiles of different versions of a software system and highlights performance‐critical changes in the system. These three blueprints helped us to significantly optimize Mondrian, an open source visualization engine. Our implementation is freely available for the Pharo development environment and has been evaluated in a number of different scenarios. Copyright © 2011 John Wiley & Sons, Ltd.     

Experimental study and analytical modeling of an alkaline water electrolysis cell

A traditional alkaline aqueous electrolyzer is investigated by using a 3‐electode structure that enables the reaction resistance of each individual electrode to be accurately monitored. Combining experimental observations with resistance‐based model analysis, we establish a quantitative relationship between current density and key voltage losses, including losses due to thermodynamics, kinetics, ohmic, and mass transport. These results demonstrate that the oxygen evolution reaction and bubble effects play crucial roles in determining electrolyzer performance. By varying the distance between electrodes, 2 effective OH^? conductivities in 0.4M KOH are found to be 0.1333 and 0.9650 second cm^?1, depending on bubble formation and release rate at the electrode interface. Moreover, bubble coverage on electrode surface achieves a steady state of 96% when current density is above 0.1 A cm^?2. In the study of various electrolyte concentrations, all the model predictions show good agreement with experimental results, confirming its ability to capture actual cell performance. This newly presented empirical resistance‐based model provides a practical framework to simulate complicated electrolysis reactions, serving as a comprehensive guide for continuous improvement of water electrolysis.     

GAS holdup and RTD measurement in an industrial flotation cell

In this work, the measurement of the axial gas holdup profile and gas residence time distribution (RTD), in a 130 m³ self-aerated flotation cell, is presented. For this purpose, a radioactive tracer gas was activated in the Nuclear Reactor of the Chilean Commission of Nuclear Energy.The gas tracer, Freon 13B1, was injected as an impulse signal at the gas (air) inlet point, located at the top of the cell, from which the gas tracer circulates first through the rotor, where the bubble dispersion occurs, and then the gas becomes well distributed over the whole cross-sectional area before leaving the cell.The axial gas holdup profile was estimated from the transient gas concentration measurement at different depths inside the cell. From these experiments it was found that the air entering the cell was preferentially distributed in the upper half of the cell, while the gas entrainment into tailings was negligible. The mean gas holdup was 8.8%, and consequently the effective pulp volume of collection zone was 91.2%.The gas concentration on top of froth was recorded for RTD measurement of the gas leaving the cell. It was found that the mean gas residence time was around 42 s and the mixing condition for gas and pulp was similar.     

Interpolating datasets with trends: A modified median polish approach

This article investigates an alternative method to deal with data sets in the presence of trends. Median polish kriging (MPK) was introduced as an alternative solution to universal kriging or intrinsic random functions of order k (IRF-k) for estimation in the presence of trends. The maps obtained using the original MPK algorithm show banding artefacts which do not appear in the reference data set. A modified version of MPK was introduced to attempt to remove the banding artefacts. The results confirm the improvement in quality of estimate using the modified version of MPK (called MPKm), which takes into account the problems of clustered samples and boundary effect associated with the re-addition of the trend along bands. The variation introduced in the median polish algorithm proved to be satisfactory in eliminating the artefacts.     

On the notion of architectural hybridisation in Latin America

The notions of hybridity and of hybridisation have been used in so many contexts, and in such diverse senses that their definition has become unclear. They are associated with the inevitable process of cultural merging that results from the simultaneity of our global culture. They are also associated with debates on migration, diaspora, global economy, and information technology. Although hybridisation is not the only term that has been used to describe and to analyse transcultural processes, it appears to be adequate to examine the nature and dynamics of the current situation of Latin American architecture. This paper seeks to demonstrate that the notion of hybridisation has been thoroughly mistaken within recent architectural debates in Latin America. This is mainly due to the fact that theorists have limited themselves largely to an architectural field, and have failed to engage sufficiently with a broader range of cultural issues. As a consequence, the notion of hybridisation has lost political efficacy and has been reduced to a problem of aesthetic syncretism, which is exactly what architectural hybridisation, as a cultural concept, is not.     

Secretome from Human Mesenchymal Stem Cells-Derived Endothelial Cells Promotes Wound Healing in a Type-2 Diabetes Mouse Model

Tissue regeneration is often impaired in patients with metabolic disorders such as diabetes mellitus and obesity, exhibiting reduced wound repair and limited regeneration capacity. We and others have demonstrated that wound healing under normal metabolic conditions is potentiated by the secretome of human endothelial cell-differentiated mesenchymal stem cells (hMSC-EC). However, it is unknown whether this effect is sustained under hyperglycemic conditions. In this study, the wound healing effect of secretomes from undifferentiated human mesenchymal stem cells (hMSC) and hMSC-EC in a type-2 diabetes mouse model was analyzed. hMSC were isolated from human Wharton’s jelly and differentiated into hMSC-EC. hMSC and hMSC-EC secretomes were analyzed and their wound healing capacity in C57Bl/6J mice fed with control (CD) or high fat diet (HFD) was evaluated. Our results showed that hMSC-EC secretome enhanced endothelial cell proliferation and wound healing in vivo when compared with hMSC secretome. Five soluble proteins (angiopoietin-1, angiopoietin-2, Factor de crecimiento fibroblástico, Matrix metallopeptidase 9, and Vascular Endothelial Growth Factor) were enriched in hMSC-EC secretome in comparison to hMSC secretome. Thus, the five recombinant proteins were mixed, and their pro-healing property was evaluated in vitro and in vivo. Functional analysis demonstrated that a cocktail of these proteins enhanced the wound healing process similar to hMSC-EC secretome in HFD mice. Overall, our results show that hMSC-EC secretome or a combination of specific proteins enriched in the hMSC-EC secretome enhanced wound healing process under hyperglycemic conditions.     

Synthesis and analysis of phase segregation of polystyrene-block-poly(methyl methacrylate) copolymer obtained by Steglich esterification from semitelechelic blocks of polystyrene and poly(methyl methacrylate)

Here, an alternative route to successfully synthesize polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) is reported. Steglich esterification was used as an effective, metal free approach for coupling carboxylic terminated PS and the hydroxyl end-functionalized PMMA chains obtained by nitroxide-mediated polymerization and atom transfer radical polymerization, respectively. α-Functionalization was obtained using 4,4′-azobis(4-cyanovaleric acid) and 2,2,2-tribromoethanol as initiators. The synthesis of PS-b-PMMA was confirmed by gel permeation chromatography and nuclear magnetic resonance (NMR), while the dependence of the diffusion coefficients of the polymers (PS, PMMA, PS/PMMA blend, and PS-b-PMMA) with their corresponding molecular weights was discussed based on the results of atomic force microscopy-based infrared spectroscopy, differential scanning calorimetry, and spectra of diffusion-ordered NMR spectroscopy. Differently from PS-b-PMMA, a partial segregation was observed for the PS/PMMA blend, affecting its thermal behavior and diffusion coefficient. The study here presented provides an easier and efficient strategy for the synthesis of PS-b-PMMA and new insights into the diffusion of polymers.     

Interfacial and emulsifying behaviour of crayfish protein isolate

The interfacial behaviour of adsorbed protein films constituted with a crayfish protein derivate that is typically produced as by-product from the food industry, has been studied at the air-water and oil-water interfaces. An analysis of the surface pressure under compression-expansion cycles of this protein was carried out as a function of time, concentration and pH (2 and 8). Besides, interfacial tension and adsorption kinetics also were determined as a function of time at different concentrations and pH values. Interfacial rheological properties were studied under dilatational deformations applied to a single droplet, either at the initial step of film formation or once the interfacial tension was at equilibrium and the film was completely formed. The contribution of the interfacial properties to the behaviour of oil-in-water emulsions stabilised with this protein derivative were also analysed. Finally, droplet size distributions obtained for concentrated emulsions stabilised by crayfish protein were analysed and related to the interfacial tension behaviour. We have demonstrated that crayfish proteins at pH 8 show higher solubility, smaller aggregates and better interfacial activity (higher surface pressure and lower interfacial tension) with higher interfacial viscoelasticity, than at pH 2. A two-dimensional model of the results showed that oil-water and air-water interfaces are clearly related to the improved stability of emulsion made with crayfish proteins at pH 8.