Intercomparisons of Mobility Size Spectrometers and Condensation Particle Counters in the Frame of the Spanish Atmospheric Observational Aerosol Network

Red Española de DMAs Ambientales (REDMAAS), the Spanish network of environmental differential mobility analyzers (DMAs), currently comprises six research groups involved in the measurement of atmospheric aerosol size distributions by means of DMAs. The aim of this network is to guarantee the good quality and comparability of the routine measurements carried out at each location and in diverse environments across Spain. In order to achieve this objective, one of its main activities is the annual intercomparison of mobility size spectrometers used within the network (five units of scanning mobility particle sizers [SMPS] and one ultrafine particle monitor [UFPM]). Here we report the 2main results obtained during the 2010–2012 campaigns, including a study on particle deposition in dryers used in ambient air sampling systems. In general, all instruments showed good performance with deviations in accepted tolerance. The intercomparisons have been proved to be a useful exercise to detect instrument problems, such as incorrect calibrations. DMA calibration checks were performed with polystyrene latex reference particles. Deviations of less than 1% were observed during the first year, which increased 4.7% during the last campaign. Some differences among the responses of different condensation particle counter (CPC) models were encountered, being mainly connected to the intrinsic characteristics of each counter. The comparison of UFPM with CPCs has given good results. The SMPS intercomparisons, especially for particles above 20 nm, have been within +/?15% tolerance. Regarding particle deposition in dryers used in sampling systems, particle penetration was lower than predicted by the recommended model. This result was probably due to the fact that not all the possible mechanisms were considered in the model.

Copyright 2015 American Association for Aerosol Research     

Individual Particle Morphology and Acidity

The morphological characterization of particles during the Pittsburgh Air Quality Study (PAQS) suggests that particle shape and physical state depends on their acidity. The aerosol shape parameters measured by Computer-Controlled Scanning Electron Microscopy (CCSEM) are statistically different in periods when atmospheric particles are neutral and when they are acidic. High concentrations of particles smaller than 500 nm with high sulfur content and liquid appearance or signs of a previous liquid state before partial or total recrystallization are present on filters collected in days with high aerosol acidity. By contrast, in winter and summer periods in which the aerosol was neutral, the shape parameter values are similar and suggest that the particles have been dried out. These direct observations support the hypothesis that during summer acidic periods in the Eastern United States the particles may contain some water even at low relative humidity both in the atmosphere and on filters.     

Application of Cognitive Techniques to Adaptive Routing for VANETs in City Environments

The evolution of smart vehicles has widened the application opportunities for vehicular ad hoc networks. In this context, the routing issue is still one of the main challenges regarding to the performance of the network. Although there are multiple ad hoc routing proposals, the traditional general-purpose approaches do not fit the distinctive properties of vehicular network environments. New routing strategies must complement the existing protocols to improve their performance in vehicular scenarios. This paper introduces a novel intelligent routing technique that makes decisions in order to adaptively adjust its operation and obtain a global benefit. The nodes sense the network locally and collect information to feed the cognitive module which will select the best routing strategy, without the need of additional protocol message dissemination or convergence mechanism.     

Processing influence on dielectric,mechanical, and electrical properties of reduced graphene oxide–TPU nanocomposites

Two different reduced graphene oxides (rGOs) with similar concentration of oxygen and defects and differences in exfoliation were prepared to produce the rGO/thermoplastic polyurethane nanocomposites by solution blending (SB) and melt compounding (MC). Morphology, electrical, and dielectric properties were studied. Large agglomerates have been observed for the composites produced by SB and discrete and low agglomerated rGO particles in the case on the composites produced by MC. These morphological differences justify the observations in hardness, electrical conductivity, and even in the dielectric properties. The composites do not follow Jonscher's universal power law (UPL) and a linear trend between UPL factors (Log A vs n) has been observed for composites produced by SB, however, no trend is observed in the composites produced by MC, being the first time observed. Differences in the tunneling effect and breakage of H-bonds within the polymer can be suggested from the dielectric relaxation characterization. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47220.     

Silver Atomic Quantum Clusters of Three Atoms for Cancer Therapy: Targeting Chromatin Compaction to Increase the Therapeutic Index of Chemotherapy

Nanomaterials with very low atomicity deserve consideration as potential pharmacological agents owing to their very small size and to their properties that can be precisely tuned with minor modifications to their size. Here, it is shown that silver clusters of three atoms (Ag₃‐AQCs)—developed by an ad hoc method—augment chromatin accessibility. This effect only occurs during DNA replication. Coadministration of Ag₃‐AQCs increases the cytotoxic effect of DNA‐acting drugs on human lung carcinoma cells. In mice with orthotopic lung tumors, the coadministration of Ag₃‐AQCs increases the amount of cisplatin (CDDP) bound to the tumor DNA by fivefold without modifying CDDP levels in normal tissues. As a result, CDDP coadministered with Ag₃‐AQCs more strongly reduces the tumor burden. Evidence of the significance of targeting chromatin compaction to increase the therapeutic index of chemotherapy is now provided.     

Input Shaping of the Synchronous Generator for Reduction of Self‐induced Oscillations

This article suggests the application of input shaping for the elimination of electromechanical oscillations arising from changes in the operating point of the synchronous generator. Poorly damped poles are the cause of electromechanical oscillations of the synchronous generator. Various power system stabilizers (PSS) are now used to reduce the electromechanical oscillations. Input shaping is a feedforward control and therefore does not require the measurement of electrical and mechanical quantities of the synchronous generator unlike the PSS. It is possible to apply the input shaping for the excitation system of synchronous generators with or without PSS.     

Normalized Cut optimization based on color perception findings. A comparative study

This paper proposes a methodology to obtain a fully automatic color segmentation algorithm based on the Normalized Cut (Ncut) proposed by Shi and Malik, using recent findings in color perception. A weighting matrix computed using a perceptually uniform color space (CIE \(L^*a^*b^*\) ) and color distance formulae correlated with the visually perceived color differences (CIE94 and CIEDE2000); a stopping condition related to perceptual criteria; an automatic parameters setting required to compute the affinity matrix are proposed. To test the proposed methodology, a wide study about the influence of the color space choice, different stopping conditions, and different similarity measurements is carried out. These alternatives are exhaustively evaluated using perception-related measurements (S-CIELAB) and general segmentation evaluation metrics applied to the 500 images of the Berkeley database. The results showed that the proposed method outperforms Ncut based on other color spaces, similarity measure or stopping conditions. Furthermore, the usability of the method is increased by replacing the manual parameter setting for an automatic.     

Antioxidant properties of polyphenol-rich cocoa products industrially processed

Fermentation and roasting are the main causes of polyphenol degradation during the process for obtaining cocoa products. In the present study, a process for obtaining polyphenol-rich cocoa products on an industrial scale is described. The process avoids the fermentation and roasting steps and includes a step for the inactivation of the enzyme Polyphenol Oxidase (PPO), which helps preserve the polyphenol content present in the raw cocoa bean. In addition, our study evaluates the antioxidant capacity and characterizes the flavonoid profile of the polyphenol-rich cocoa products obtained from the natural polyphenol-rich cocoa cake. Using different protocols, we have obtained three cocoa extracts with high polyphenol content, namely extracts A (167 mg/g), B (374 mg/g) and C (787 mg/g). The scavenging capacity of the extracts was measured as their ability to bleach the stable radicals DPPH and ABTS⁺ while their antioxidant effect was evaluated with the FRAP assay. The results for A, B and C in the DPPH test expressed as Trolox equivalent (μmol)/mg dry weight of extract were 0.2, 1.4 and 3.0, respectively; in the ABTS test the results were 1.0, 4.7 and 9.8. The antioxidant capacity expressed as ascorbic acid equivalent (μmol)/mg dry weight of each product were 17.2, 76.1 and 207.7, respectively. The scavenging properties of cocoa powder against the superoxide anion, H₂O₂, HClO, and peroxynitrite were also determined. The IC₅₀ (μg/mL) values in the hypoxanthine/xanthine oxidase test were 77.5, 12.3 and 10.3, for A, B and C, respectively, while as an HOCl scavenger the IC₅₀ (μg/mL) values were 225.4, 73.2 and 21.5. As a peroxynitrite anion scavenger, only extract C had a relevant effect, with IC₅₀ (μg/mL) values of 76.1 or 110.0 in the absence or presence of bicarbonate. None of the extracts tested showed activity in the hydrogen peroxide test, but B and C significantly increased the deoxyribose degradation in the absence of ascorbate. Likewise, none of the extracts inhibited the ferrous or copper chelating activity at 100 μg/mL, but they inhibited the lipid peroxidation in brain homogenates and human plasma through non-enzymatic generation systems, with extract C giving the best IC₅₀ (μg/mL) values: 17.4 and 8.1 against lipid peroxidation in brain homogenates and human plasma, respectively. In conclusion, if the extractive protocol is well characterized, defined and optimized, cocoa could constitute a source of polyphenols for enriching foods, nutraceuticals and alimentary supplements.     

Influence of storage period and packaging method on sliced dry cured beef "Cecina de Leon": Effects on microbiological, physicochemical and sensory quality

Quality aspects of sliced dry-cured beef “Cecina de León” preserved in vacuum and gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂) were studied. The evolution of microbiological, physicochemical and sensory parameters were analysed during storage (210 days) at 6 °C. Although microbial counts at 60 days of the gas-packaged samples were lower than the vacuum-packed ones, they were never higher than the spoilage limit (7 log ufc/g). A slight increase (p < 0.05) in pH was observed throughout storage of “Cecina de León” packaged under vacuum and in gas mixtures. However, a decrease (p < 0.05) in a_w was observed during storage of “Cecina de León” packaged under vacuum but a_w did not vary (p > 0.05) during storage in the gas-packaged samples. No changes were observed (p > 0.05) in lightness (L^*), redness (a^*) and yellowness (b^*) in vacuum and gas packaged samples during storage. However, sensorially evaluated colour showed lower values in gas packaged samples during 30 days storage. This difference was decisive in establishing the shelf-life of “Cecina de León” slices preserved in gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂). Therefore, from a microbiological point of view, gas mixtures are more effective in extending the shelf-life of “Cecina de León” slices. It is concluded that vacuum packaging allows longer storage than gas-packaging as it maintains a good visual appearance of “Cecina de León”, the main parameter in consumers’ perception of meat quality.     

Design and development of meat-based functional foods with walnut: Technological,nutritional and health impact

With growing understanding of the relationship between diet and health has come the emergence of so-called functional foods. The idea of using food for health purposes and not merely as a source of nutrients opens up a whole new field in the meat industry. In addition to traditional presentations, there a number of ways in which the meat sector can modify the qualitative and quantitative composition of meat and meat product components and produce designer foods with specific properties. This entails addressing quality factors associated with different product properties (sensory and technological properties, hygiene, convenience, stability, etc.), nutritional value (balanced composition and bioactive substances) and their effects on physiological function and health. This article reviews a comprehensive model for the development of meat-based functional foods based on a presentation of the research achieved in terms of the design and development of qualitatively and quantitatively modified meat products (through reformulation) in nutrients associated with cardiovascular risk (walnut as a source of bioactive substances). It also discusses their bioavailability and the effect of their consumption on intermediate cardiovascular risk markers in humans.