Invariant image reconstruction from irregular samples and hexagonal grid splines

We present an algorithm for the reconstruction of images from irregularly placed samples, using linear splines with control points on a hexagonal grid. Several spline approximations are computed for different transformations of the control point grid (e.g. translations and rotations). These approximations are then merged together after compensation of the transformations, yielding a high-quality invariant image reconstruction. Evaluations show that the use of hexagonal grids of the “invariance by integration” principle improves reconstruction quality. An application to image coding is also presented.     

Water retention and gas relative permeability of two industrial concretes

This experimental study aims at identifying the water retention properties of two industrial concretes to be used for long term underground nuclear waste storage structures. Together with water retention, gas transfer properties are identified at varying water saturation level, i.e. relative gas permeability is assessed directly as a function of water saturation level S_w. The influence of the initial de-sorption path and of the subsequent re-saturation are analysed both in terms of water retention and gas transfer properties. Also, the influence of concrete microstructure upon water retention and relative gas permeability is assessed, using porosity measurements, analysis of the BET theory from water retention properties, and MIP. Finally, a single relative gas permeability curve is proposed for each concrete, based on Van Genuchten–Mualem's statistical model, to be used for continuous modelling approaches of concrete structures, both during drying and imbibition.     

Influence of the Pathogen <Emphasis Type="Italic">Candidatus</Emphasis> Liberibacter Solanacearum on Tomato Host Plant Volatiles and Psyllid Vector Settlement

Candidatus Liberibacter solanacearum (CLso) is an unculturable bacterium vectored by the tomato potato psyllid (TPP) Bactericera cockerelli and has been associated with Zebra chip disease in potato and with other economically relevant symptoms observed in solanaceous crops. By altering their host and vector’s biological system, pathogens are able to induce changes that benefit them by increasing their transmission rate. Understanding these changes can enable better targeting of mechanisms to control pathogen outbreaks. Here, we explored how the CLso infectious status affects the volatile organic compounds (VOCs) of the tomato plant, and whether the CLso infectious status of TPP influences host plant settlement. These chemical and behavioral changes can ultimately affect the rate of encounter between the host and the vector. Results from headspace volatile collection of tomato plants showed that CLso infected tomato plants emitted a qualitatively and quantitatively different blend of VOCs compared to sham-infected plants. By a factorial experiment, we showed that CLso negative (CLso-) TPP preferred to settle 70 % more often on infected tomato plants, while CLso positive (CLso+) TPP were found 68 % more often on sham-infected tomato plants. These results provide new evidence in favor of both host and vector manipulation by CLso.     

Viability and surface properties of spores subjected to a cleaning-in-place procedure: Consequences on their ability to contaminate surfaces of equipment

This study was designed to evaluate how conditions encountered by spores during cleaning-in-place (CIP) procedures affected their surface properties, their viability and ability to contaminate materials. Spores from five Bacillus cereus strains were treated with NaOH at high temperature. Results revealed that high temperatures (exceeding 60 °C) and NaOH concentrations (over 0.5%) were required to significantly decrease spore viability (3–5 log decrease). In these conditions, modifications were also clearly observed by microscopy to various surface structures of spores (appendages, exosporium, and especially to the hair-like nap) but also to their coat. Therefore, the ability of culturable spores to adhere decreased for the majority of strains tested. We then demonstrated that spores in suspension in NaOH could adhere to surfaces of a CIP rig and that the contamination level was controlled by flow pattern. Consequently, re-adhesion along the processing line might occur during CIP procedures and this phenomenon must be taken into account when defining cleaning strategies.     

Factors Influencing Recovery of Heat-injured Bacillus thuringiensis Spores. Statistical Approach

The influence of several factors on recovery of heat-treated Bacillus thuringiensis spores was examined including treatment conditions (time/temperature), dilution buffer (phosphate buffer, peptone water at 15 mg/L), recovery temperature and enumeration medium constituents (lysozyme, catalase, lactic acid hemicalcium salt, glucose, MgSO₄, sodium chloride). A fractional factorial design was used to determine the incidence and interactions of these factors. Specific significant factors (treatment conditions, dilution buffer, recovery temperature, glucose and NaCl addition) were derived from this analysis and then tested in a general linear regression model which assessed their influences. The maximal count was obtained when spores diluted in peptone buffer were incubated at 25°C in nutrient agar containing NaCl and glucose.     

Effect of phosphate source,rate and cadmium content and use of Penicillium bilaii on phosphorus,zinc and cadmium concentration in durum wheat grain

Field studies were conducted over 3 years at several locations in Alberta and Manitoba, Canada to evaluate the impact of phosphate fertiliser containing varying concentrations of Cd on grain yield and P, Zn and Cd concentration in durum wheat grain. The effect of a seed treatment with Penicillium bilaii, a phosphate‐solubilising fungus, was also examined. P bilaii had little effect on crop yield, nutrient concentration or the concentration of Cd in the grain under the conditions of this study. Fertilisation with monoammonium phosphate consistently increased Cd concentration and Cd/Zn ratio and decreased Zn concentration in durum wheat. Increases in Cd concentration in durum wheat were unrelated to Cd concentration in the fertiliser, although the concentration of Cd in the fertiliser sources varied from 0.2 to 186.0 µg g^?1. Increased Cd concentration with phosphate application may be related to high ionic strength, reduced pH and enhanced root proliferation in the microregion around the fertiliser granules. Enhanced root development in response to phosphate fertilisation may increase the accumulation of Cd. Reduction in Zn accumulation associated with phosphate application may also contribute to the increase in Cd concentration in durum grain, possibly through enhancement of Cd translocation to the grain. While reduction in Cd concentration in phosphate fertilisers will reduce long‐term Cd accumulation in soils, use of low‐Cd fertiliser at commercially practical levels of fertilisation is unlikely to reduce Cd concentration in durum wheat in the year of application. © 2002 Society of Chemical Industry     

Mechanical properties of impregnated asbestos-cement

This study is devoted to the mechanical properties of impregnated asbestos-cements. We studied the influence of the degree of impregnation and of the nature of the resin on the modulus of elasticity and on the strength of the materials. The impregnation of asbestos-cement by polymeric resins produces composites of outstanding mechanical properties. The relative increase in flexural and tensile strength is much higher for mortar and concrete but the improvement produced by the polymer on asbestos-cement is especially significant if one takes into consideration the already high absolute strengths of the materials.     

Multi-Fidelity High-Throughput Optimization of Electrical Conductivity in P3HT-CNT Composites

Combining high-throughput experiments with machine learning accelerates materials and process optimization toward user-specified target properties. In this study, a rapid machine learning-driven automated flow mixing setup with a high-throughput drop-casting system is introduced for thin film preparation, followed by fast characterization of proxy optical and target electrical properties that completes one cycle of learning with 160 unique samples in a single day, a > 10 ×  improvement relative to quantified, manual-controlled baseline. Regio-regular poly-3-hexylthiophene is combined with various types of carbon nanotubes, to identify the optimum composition and synthesis conditions to realize electrical conductivities as high as state-of-the-art 1000 S cm⁻¹. The results are subsequently verified and explained using offline high-fidelity experiments. Graph-based model selection strategies with classical regression that optimize among multi-fidelity noisy input-output measurements are introduced. These strategies present a robust machine-learning driven high-throughput experimental scheme that can be effectively applied to understand, optimize, and design new materials and composites.     

Cardiac output response to dynamic exercise after atrial switch repair for transposition of the great arteries

Results from this study showed that patients who underwent successful operation for transposition of the great arteries had no appropriate increase in stroke volume in response to exercise of a nature similar to common recreational activities. The impairment, most likely due to disturbances in both venous return and ventricular systolic function, is compensated for by an increase in peripheral oxygen extraction; however, this increase may not be adequate with maturation or during prolonged exercise when cardiovascular constraints are more important.