Exposure to ultrafine particles in children until 18 years of age: A systematic review

Airborne ultrafine particles (UFP) have been related to adverse health effects, but exposure in vulnerable population groups such as children is still not well understood. We aim to review the scientific literature regarding personal exposure to UFP in different microenvironments in populations until 18 years of age. The bibliographical search was carried out in July 2019 using the online database PubMed and was completed with references in articles found in the search. We selected the studies that used continuous counters and measured UFP levels in both specific microenvironment (houses, schools, transport, etc) and personal exposure. Finally, 32 studies fulfilled the criteria: of these, 10 analyzed personal exposure and 22 examined UFP levels in the microenvironment (especially in schools or nurseries (18/22)) and five in various microenvironments (including dwellings and means of transport, where exposure levels were higher). The characteristics of the microenvironments with the greatest levels of UFP were being close to heavy traffic or near cooking and cleaning activities. This review revealed the wide differences in exposure assessment methodologies that could lead to a lack of uniform and comparable information about the real UFP exposure in children.     

Effect of the particle size of pear pomace on the quality of enriched layer and sponge cakes

Pear pomace (PP) is a by-product of the fruit industry with a high content of fibre. Its potential as an ingredient at 15% or 30% level for sponge and layer cakes was investigated. Three PP powders with different particle sizes (fine, medium and coarse) were obtained. Batter microstructure, density and viscosity and cake specific volume, texture and colour were evaluated. When PP was added, less uniformity in bubble distribution was observed in batters, particularly at higher particle sizes. Cake specific volume significantly diminished with increasing amounts of PP. For sponge cakes, the decrease in specific volume was the highest for the finest particle size of PP. In general, increasing PP addition increased hardness and reduced elasticity, cohesiveness and resilience but the effect depended on the particle size. In general, better textural attributes were obtained with medium and coarse particle sizes. These results indicate that PP of an adequate particle size could be a promising fibre source for different cake formulations.     

Rheological properties of rice–locust bean gum gels from different rice varieties

Pasting and gelatinization behavior of rice gels from Japonica (Ariete, Euro), Indica (Gladio, Suriname) and waxy (Glutinous) varieties were analyzed. These varieties differ widely in amylose contents and differential scanning calorimetry (DSC) gelatinization temperatures. Besides, the effect of locust bean gum (LBG) addition and the impact of successive viscoanalyser multiple-heating–cooling and freezing–thawing cycles on the gels pasting viscosities (peak-η_peak, trough-η_min, final-η_final), viscoelasticity by oscillatory rheometry and syneresis were evaluated.     

Correction of photoresponse nonuniformity for matrix detectors based on prior compensation for their nonlinear behavior

What we believe to be a novel procedure to correct the nonuniformity that is inherent in all matrix detectors has been developed and experimentally validated. This correction method, unlike other nonuniformity-correction algorithms, consists of two steps that separate two of the usual problems that affect characterization of matrix detectors, i.e., nonlinearity and the relative variation of the pixels' responsivity across the array. The correction of the nonlinear behavior remains valid for any illumination wavelength employed, as long as the nonlinearity is not due to power dependence of the internal quantum efficiency. This method of correction of nonuniformity permits the immediate calculation of the correction factor for any given power level and for any illuminant that has a known spectral content once the nonuniform behavior has been characterized for a sufficient number of wavelengths. This procedure has a significant advantage compared with other traditional calibration-based methods, which require that a full characterization be carried out for each spectral distribution pattern of the incident optical radiation. The experimental application of this novel method has achieved a 20-fold increase in the uniformity of a CCD array for response levels close to saturation.     

Apparent violation of the radiant exposure reciprocity law in interline CCDs

We analyze in detail the apparent violation of the reciprocity law that occurs for an interline CCD array owing to its responsivity that varies with exposure time, and we investigate other parameters having an influence on this variation, such as the numerical aperture of the system or the illumination wavelength. The variation can be explained from a qualitative point of view by the charge leakage that occurs from the sense region to the register region during readout time. This change of the responsivity can be avoided either by using a synchronized external shutter or by limiting the numerical aperture while keeping relatively high exposure times. A detailed characterization for each particular CCD model must be carried out if it is to be employed in low-uncertainty radiometric measurements.     

Ferroelectric Response and Induced Biaxiality in the Nematic Phase of Bent‐Core Mesogens

The still undiscovered fluid ferroelectric nematic phase is expected to exhibit a much faster and easier response to an external electric field compared to conventional ferroelectric smectic liquid crystals; therefore, the discovery of such a phase could open new avenues in electro‐optic device technology. Here, experimental evidence of a ferroelectric response to a switching electric field in a low molar mass nematic liquid crystal is reported and connected with field‐induced biaxiality. The fluid is made of bent‐core polar molecules and is nematic over a range of 120 °C. Combining repolarization current measurements, electro‐optical characterizations, X‐ray diffraction and computer simulations, ferroelectric switching is demonstrated and it is concluded that the response is due to field‐induced reorganization of polar cybotactic groups within the nematic phase. This work represents significant progress toward the realization of ferroelectric fluids that can be aligned at command with a simple electric field.     

A virtual environment for remote testing of complex systems

Complex systems, realized by integration of several components or subsystems, pose specific problems to simulation environments. It is, in fact, desirable to simulate the complex system altogether, and not component by component, since the operation of the single part depends on the surrounding system and an early verification can prevent damages and save time for modifications. The availability of detailed and validated models of the single parts is therefore critical. This task may be difficult to achieve. In fact, in industrial applications, where a system can be a mix of different devices produced by different manufacturers, the physical device may not be accessible to the modeler for proprietary or safety concerns. Starting from this point, the idea of creating a virtual environment able to test the real single component remotely, employing simulators with remote signal processing capability, has been considered. A methodology for remote model validation is presented. The effectiveness of the approach is experimentally verified locally and remotely. For the remote testing, in particular, the physical device under test is located at the Politecnico di Milano, Italy, and the Virtual Test Bed model is located at the University of South Carolina.     

Techno‐functional properties of wheat flour‐resistant starch mixtures applied to breadmaking

Resistant starch can be used to reduce the availability of carbohydrates in baked products. In this study, the effect of type 4 resistant wheat starch (RS₄) on wheat flour dough and breads was evaluated. Wheat flour was substituted by RS₄ at 10%, 20% and 30% w/w (RS10, RS20 and RS30, respectively). Rheological and thermal behaviours of dough were evaluated. Besides, bread quality, starch digestibility and bread staling were analysed. All substituted dough exhibited viscoelastic behaviour but lower elastic and viscous moduli. Regarding to bread quality, specific volume and crumb texture were negatively affected in samples with RS₄. However, all samples were technologically acceptable. During storage, crumb hardening was observed in breads without and with RS₄ but amylopectin retrogradation was not particularly affected. The in vitro digestibility of bread with RS showed a lower release of reducing sugars and a lower estimated glycaemic index, suggesting a healthier profile for these breads.     

Electrophysiologic models of heart cells and cell networks

This article summarizes the basic principles of action potential models, reviews the development of cellular models of normal and diseased cells, and discusses some important contributions of computer simulations to the understanding of arrhythmia generation in heart-cell networks. The article should enable a better understanding of arrhythmias and heart disease