Erratum: Guillermo M., et al. Environmental Impact of Nanoparticles' Application as an Emerging Technology: A Review. Materials 2021, 14, 166.

The authors wish to make the following corrections to this paper [...].

Environmental Impact of Nanoparticles' Application as an Emerging Technology: A Review.

The unique properties that nanoparticles exhibit, due to their small size, are the principal reason for their numerous applications, but at the same time, this might be a massive menace to the environment. The number of studies that assess the possible ecotoxicity of nanomaterials has been increasing over the last decade to determine if, despite the positive aspects, they should be considered a potential health risk. To evaluate their potential toxicity, models are used in all types of organisms, from unicellular bacteria to complex animal species. In order to better understand the environmental consequences of nanotechnology, this literature review aims to describe and classify nanoparticles, evaluating their life cycle, their environmental releasing capacity and the type of impact, particularly on living beings, highlighting the need to develop more severe and detailed legislation. Due to their diversity, nanoparticles will be discussed in generic terms focusing on the impact of a great variety of them, highlighting the most interesting ones for the industry.

Lipid Exchange Factors at Membrane Contact Sites in African Swine Fever Virus Infection.

African swine fever (ASF) is a hemorrhagic fever of wild and domestic pigs with a high rate of mortality. Originally endemic in Africa, this disease is currently disseminating in Europe and China, causing a large socioeconomic impact. ASF is caused by a DNA virus, African swine fever virus (ASFV). There is no vaccine available against ASFV, limiting the options for disease control. ASFV reorganizes intracellular membranes to generate viral factories (VFs) in order to amplify its genome. However, little is known about the process involved in the formation of these viral replication organelles. Membrane contact sites (MCSs) allow nonvesicular lipids and ion exchange between organelles. Lipid exchange to form VFs apparently requires a number of proteins at MCSs, such as the oxysterol-binding protein (OSBP), the acyl-coenzyme A binding domain containing 3 (ACBD3) and the phosphatidylinositol-phosphate-4-kinase III beta (PI4Kß). Itraconazole (ITZ) is an antifungal agent that targets sterol-transport molecules such as OSBP and OSBP-related protein 4 (ORP4). 25-Hydroxycholesterol (25-HC) inhibits lipid transport by high affinity binding OSBP. In this work, we analyzed the antiviral function of ITZ and 25-HC against ASFV in Vero cell cultures using the cell-adapted Ba71V isolate. ITZ and 25-HC decreased significantly ASFV replication. Our study revealed OSBP distribution in cytoplasmic membranes in uninfected Vero cells and to the periphery of VFs in infected cells. In addition, we showed that OSBP and OSBP-related proteins, PI4Kß and ACBD3 were recruited to VFs in the context ASFV infection.

A Nucleotide-Dependent Conformational Switch Controls the Polymerization of Human IMP Dehydrogenases to Modulate their Catalytic Activity.

Inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes the rate-limiting step in the de novo GTP biosynthetic pathway and plays essential roles in cell proliferation. As a clinical target, IMPDH has been studied for decades, but it has only been within the last years that we are starting to understand the complexity of the mechanisms of its physiological regulation. Here, we report structural and functional insights into how adenine and guanine nucleotides control a conformational switch that modulates the assembly of the two human IMPDH enzymes into cytoophidia and allosterically regulates their catalytic activity. In vitro reconstituted micron-length cytoophidia-like structures show catalytic activity comparable to unassembled IMPDH but, in turn, are more resistant to GTP/GDP allosteric inhibition. Therefore, IMPDH cytoophidia formation facilitates the accumulation of high levels of guanine nucleotides when the cell requires it. Finally, we demonstrate that most of the IMPDH retinopathy-associated mutations abrogate GTP/GDP-induced allosteric inhibition and alter cytoophidia dynamics.

Analysis of the Microstructure and Mechanical Properties of Titanium-Based Composites Reinforced by Secondary Phases and B4C Particles Produced via Direct Hot Pressing.

In the last decade, titanium metal matrix composites (TMCs) have received considerable attention thanks to their interesting properties as a consequence of the clear interface between the matrix and the reinforcing phases formed. In this work, TMCs with 30 vol % of B4C are consolidated by hot pressing. This technique is a powder metallurgy rapid process. Incorporation of the intermetallic to the matrix, 20 vol % (Ti-Al), is also evaluated. Here, the reinforcing phases formed by the reaction between the titanium matrix and the ceramic particles, as well as the intermetallic addition, promote substantial variations to the microstructure and to the properties of the fabricated composites. The influences of the starting materials and the consolidation temperature (900 °C and 1000 °C) are investigated. By X-ray diffraction, scanning and transmission electron microscopy analysis, the in-situ-formed phases in the matrix and the residual ceramic particles were studied. Furthermore, mechanical properties are studied through tensile and bending tests in addition to other properties, such as Young's modulus, hardness, and densification of the composites. The results show the significant effect of temperature on the microstructure and on the mechanical properties from the same starting powder. Moreover, the Ti-Al addition causes variation in the interface between the reinforcement and the matrix, thereby affecting the behaviour of the TMCs produced at the same temperature.

Analysis of the Influence of Starting Materials and Processing Conditions on the Properties of W/Cu Alloys.

In this work, a study of the influence of the starting materials and the processing time used to develop W/Cu alloys is carried out. Regarding powder metallurgy as a promising fabrication route, the difficulties in producing W/Cu alloys motivated us to investigate the influential factors on the final properties of the most industrially demanding alloys: 85-W/15-Cu, 80-W/20-Cu, and 75-W/25-Cu alloys. Two different tungsten powders with large variation among their particle size-fine (Wf) and coarse (Wc) powders-were used for the preparation of W/Cu alloys. Three weight ratios of fine and coarse (Wf:Wc) tungsten particles were analyzed. These powders were labelled as "tungsten bimodal powders". The powder blends were consolidated by rapid sinter pressing (RSP) at 900 °C and 150 MPa, and were thus sintered and compacted simultaneously. The elemental powders and W/Cu alloys were studied by optical microscopy (OM) and scanning electron microscopy (SEM). Thermal conductivity, hardness, and densification were measured. Results showed that the synthesis of W/Cu using bimodal tungsten powders significantly affects the final alloy properties. The higher the tungsten content, the more noticeable the effect of the bimodal powder. The best bimodal W powder was the blend with 10 wt % of fine tungsten particles (10-Wf:90-Wc). These specimens present good values of densification and hardness, and higher values of thermal conductivity than other bimodal mixtures.

Enhanced plastochromanol-8 accumulation during reiterated drought in maize (Zea mays L.).

Plastochromanol-8 (PC-8) belongs to the group of tocochromanols, and together with tocopherols and carotenoids, might help protect photosystem II from photoinhibition during environmental stresses. Here, we aimed to unravel the time course evolution of PC-8 together with that of vitamin E compounds, in maize (Zea mays L.) plants exposed to reiterated drought. Measurements were performed in plants grown in a greenhouse subjected to two consecutive cycles of drought-recovery. PC-8 contents, which accounted for more than 25% of tocochromanols in maize leaves, increased progressively in response to reiterated drought stress. PC-8 contents paralleled with those of vitamin E, particularly α-tocopherol. Profiling of the stress-related phytohormones (ABA, jasmonic acid and salicylic acid) was consistent with a role of ABA in the regulation of PC-8 and vitamin E biosynthesis during drought stress. Results also suggest that PC-8 may help tocopherols prevent damage to the photosynthetic apparatus. A better knowledge of the ABA-dependent regulation of PC-8 may help us manipulate the contents of this important antioxidant in crops.

Drought stress memory in the photosynthetic mechanisms of an invasive CAM species, Aptenia cordifolia.

Plants are known for their high capacity to acclimatise to fluctuating environmental conditions. A wide range of environmental conditions can lead to suboptimal physiological efficiency. However, recent studies have shown that plants can withstand repeated periods of stress. To find out how they do it, we studied photosynthetic adjustments to repeated water stress in Aptenia cordifolia: a facultative, invasive CAM species. Plants were subjected to three cycles of water deficit, and photosynthetic parameters and chloroplast antioxidants were quantified to gain an understanding of the mechanisms by which they cope with repeated stress periods. Significant modification of the photosystems' antenna and reaction centres was observed in plants subjected to previous water stress cycles, and this led to higher PSII efficiency than in plants challenged with drought for the first time. These findings underline the biological significance of stress memory and show how plants can adjust their photosynthetic apparatus to fluctuating environmental conditions and thus optimise photosynthesis and photoprotection under drought conditions.

Adaptation of the Long-Lived Monocarpic Perennial Saxifraga longifolia to High Altitude.

Global change is exerting a major effect on plant communities, altering their potential capacity for adaptation. Here, we aimed at unveiling mechanisms of adaptation to high altitude in an endemic long-lived monocarpic, Saxifraga longifolia, by combining demographic and physiological approaches. Plants from three altitudes (570, 1100, and 2100 m above sea level [a.s.l.]) were investigated in terms of leaf water and pigment contents, and activation of stress defense mechanisms. The influence of plant size on physiological performance and mortality was also investigated. Levels of photoprotective molecules (α-tocopherol, carotenoids, and anthocyanins) increased in response to high altitude (1100 relative to 570 m a.s.l.), which was paralleled by reduced soil and leaf water contents and increased ABA levels. The more demanding effect of high altitude on photoprotection was, however, partly abolished at very high altitudes (2100 m a.s.l.) due to improved soil water contents, with the exception of α-tocopherol accumulation. α-Tocopherol levels increased progressively at increasing altitudes, which paralleled with reductions in lipid peroxidation, thus suggesting plants from the highest altitude effectively withstood high light stress. Furthermore, mortality of juveniles was highest at the intermediate population, suggesting that drought stress was the main environmental driver of mortality of juveniles in this rocky plant species. Population structure and vital rates in the high population evidenced lower recruitment and mortality in juveniles, activation of clonal growth, and absence of plant size-dependent mortality. We conclude that, despite S. longifolia has evolved complex mechanisms of adaptation to altitude at the cellular, whole-plant and population levels, drought events may drive increased mortality in the framework of global change.

Stress Memory and the Inevitable Effects of Drought: A Physiological Perspective.

Plants grow and develop by adjusting their physiology to changes in their environment. Changes in the abiotic environment occur over years, seasons, and days, but also over minutes and even seconds. In this ever-changing environment, plants may adjust their structure and function rapidly to optimize growth and reproduction. Plant responses to reiterated drought (i.e., repeated cycles of drought) differ from those to single incidences of drought; in fact, in nature, plants are usually exposed to repeated cycles of drought that differ in duration and intensity. Nowadays, there is increased interest in better understanding mechanisms of plant response to reiterated drought due, at least in part, to the discovery of epigenomic changes that trigger drought stress memory in plants. Beyond epigenomic changes, there are, however, other aspects that should be considered in the study of plant responses to reiterated drought: from changes in other "omics" approaches (transcriptomics, proteomics, and metabolomics), to changes in plant structure; all of which may help us to better understand plant stress memory and its underlying mechanisms. Here, we present an example in which reiterated drought affects the pigment composition of leaves in the ornamental plant Silene dioica and discuss the importance of structural changes (in this case in the photosynthetic apparatus) for the plant response to reiterated drought; they represent a stress imprint that can affect plant response to subsequent stress episodes. Emphasis is placed on the importance of considering structural changes, in addition to physiological adjustments at the "omics" level, to understand stress memory in plants better.

Evidence of Drought Stress Memory in the Facultative CAM, Aptenia cordifolia: Possible Role of Phytohormones.

Although plant responses to drought stress have been studied in detail in several plant species, including CAM plants, the occurrence of stress memory and possible mechanisms for its regulation are still very poorly understood. In an attempt to better understand the occurrence and possible mechanisms of regulation of stress memory in plants, we measured the concentrations of phytohormones in Aptenia cordifolia exposed to reiterated drought, together with various stress indicators, including leaf water contents, photosynthesis and mechanisms of photo- and antioxidant protection. Results showed that plants exposed to drought stress responded differently if previously challenged with a first drought. Gibberellin levels decreased upon exposure to the first drought and remained lower in double-stressed plants compared with those exposed to stress for the first time. In contrast, abscisic acid levels were higher in double- than single-stressed plants. This occurred in parallel with alterations in hydroperoxide levels, but not with malondialdehyde levels, thus suggesting an increased oxidation state that did not result in oxidative damage in double-stressed plants. It is concluded that (i) drought stress memory occurs in double-stressed A. cordifolia plants, (ii) both gibberellins and abscisic acid may play a role in plant response to repeated periods of drought, and (iii) changes in abscisic acid levels in double-stressed plants may have a positive effect by modulating changes in the cellular redox state with a role in signalling, rather than cause oxidative damage to the cell.

Tocochromanols in wood: a potential new tool for dendrometabolomics.

Tocochromanols are the most abundant lipid-soluble antioxidants in plants. Among them, α-tocopherol (α-Toc) shows a particularly high sensitivity to environmental stressors and its content is used as a stress biomarker even in non-photosynthetic tissues. Nevertheless, the presence of tocochromanols has not been described yet in the xylem of woody plants, even when their functions regarding cell membrane protection and the transport of photoassimilates may be crucial in this tissue and despite its potential utility in dendrometabolomics. Considering all these, we aimed to determine the presence and distribution of tocochromanols in the xylem of woody plants, to examine their responsiveness to high temperature and to evaluate their potential as environmental bioindicators. The analysis of 29 phyllogenetically diverse species showed that α-Toc is the most abundant and frequent tocochromanol in the xylem and is ubiquitously present in all the studied species, with a concentration ranging from 0.5 to 39.3 µg g(-1) of dry weight. α-Tocopherol appeared to be mainly located in the parenchyma rays and was found in both the sapwood and the heartwood, suggesting that it is present even in dead parenchyma cells. The levels of α-Toc in the xylem did not change in response to locally induced xylem heating, but responded positively to the 3-year moving average of annual precipitation. The present findings suggest that α-Toc may be linked to changes in climatic stress. This should enhance further research on the environmental controls of α-Toc variation in the xylem as a first step towards a deeper understanding of dendrometabolomics.

Migration of antimicrobial silver from composites of polylactide with silver zeolites.

UNLABELLED: Silver ion migration and antimicrobial activity of PLA (polylactic acid-polylactide)/silver zeolite composites were investigated. Films prepared by solution-casting/solvent evaporation, or by melt-mixing/compression molding were compared. Silver migration to food simulants and TSB (tryptone soy broth) was quantified at different temperatures. Antimicrobial activity against Staphylococcus aureus and Escherichia coli was measured following the Japanese Industrial Standard JIS Z 2801. All types of PLA/silver zeolite composites released Ag(+) ions. A more intense ionic exchange with the zeolites and a significant, but low, antimicrobial activity in solution were found in cast films. To attain antimicrobial effects, however, migrated ions ought to be in the range of the legal limit of 0.05 mg Ag(+)/kg food stated by the European Food Safety Agency (EFSA). Silver migration and antimicrobial activity were sensitive to the methodology chosen to process the PLA films, the ionic strength of the medium, and the ion motility in the polymer matrix. PRACTICAL APPLICATION: Silver exchanged zeolites incorporated in food contact polymers are gaining importance as antimicrobial agents. Migration of silver ions from polymer matrices, however, is legally restricted. Therefore a compromise between silver migration and antimicrobial activity needs to be critically analyzed to validate novel materials in food packaging applications.

Evaluación de la ingesta de grasas y minerales en un grupo de ciclistas de equipos juvenil y sub-23 / Evaluation of fat and mineral intake by a group of cyclists belonging to junior and sub-23 teams

Introducción. El propósito fue determinar si un equipo de 34 ciclistas españoles jóvenes sigue las pautas recomendadas en la ingesta de macronutrientes (principalmente grasas) y minerales (sodio, calcio, potasio y magnesio). Una dieta desequilibrada a largo plazo está asociada a enfermedades crónicas tales como obesidad, dislipemias, arteriosclerosis e hipertensión arterial (HTA). Es fundamental la formación nutricional de los jóvenes promoviendo hábitos saludables y también una alimentación que favorezca el rendimiento deportivo a corto plazo. Material y método. Evaluación nutricional basada en la ingesta reportada en un cuestionario de 7 días consecutivos. Resultados. Un porcentaje de los ciclistas estudiados consume cantidades excesivas de colesterol (94% de los ciclistas), grasas saturadas, ácido grasos saturados (74%) y sodio (47%), mientras que no consumen las cantidades recomendadas de calcio (29%), magnesio (10%) y potasio (44%). Esta misma tendencia se ha observado en la población general de jóvenes españoles del estudio en Kid. Conclusiones. Este trabajo ha contribuido a un mejor conocimiento de la dieta que siguen jóvenes que son muy activos físicamente. La dieta que sigue un porcentaje de los ciclistas jóvenes estudiados presenta desequilibrios nutricionales (excesivo consumo de grasas y sodio), que se deben corregir educando no solamente a los ciclistas, sino también a los padres y entrenadores. Se debe fomentar la correcta hidratación con electrolitos y la dieta mediterránea, rica en vegetales, frutas, pescado y aceite de oliva, lo que proporciona la cantidad adecuada de grasas monoinsaturadas (AGM) y poliinsaturadas (AGP) que protegen el sistema cardiovascular (AU)

Introduction. The aim of this study was to determine whether 34 young Spanish males belonging to Junior and Sub-23 cycling teams followed recommendations for optimal macronutrient (mainly fats) and mineral (sodium, calcium, potassium and magnesium) intake. In the long term, an unbalanced diet has been associated with chronic diseases such as obesity, dyslipidemia, atherosclerosis, and hypertension. Promotion of nutritional education is essential to achieve good nutritional practices in the long term, while precompetition diets aiming to improve the sporting performance of young cyclists are important in the short term. Material and method. Nutritional evaluation was based on the intake reported over 7 consecutive days in a questionnaire. Results. A percentage of the cyclists studied consumed excessive quantities of cholesterol (94% of cyclists), saturated fats (74%), and sodium (47%) and did not consume the recommended quantities of calcium (29%), magnesium (10%) and potassium (44%). The same nutritional pattern was found in young Spanish males in the EnKid study. Conclusions. The present study increases knowledge of the diets followed by highly active young Spanish males. A percentage of these cyclists followed unbalanced diets (excessive intake of fats and sodium) that should be modified by educating not only the cyclists, but also their parents and coaches. Adequate hydration (water and electrolytes) and the Mediterranean diet, rich in vegetables, fruits, fish and olive oil, should be promoted to ensure appropriate intake of fats (monounsaturated and polyunsaturated fatty acids) to protect the cardiovascular system (AU)

Desequilibrios en el consumo de lácteos y derivados en un colectivo de ciclistas jóvenes y su comparación con jóvenes homólogos / No disponible

Introducción: El propósito de este trabajo ha sido determinarel consumo de lácteos en un equipo de ciclistas jóvenes enrelación con las pautas recomendadas y compararlo con elde los jóvenes españoles del estudio enKID.Método: Evaluación nutricional en un estudio observacionaltransversal basada en la ingesta reportada en un cuestionariode 7 días consecutivos por un colectivo de 47 ciclistasvarones jóvenes.Resultados: Para los jóvenes ciclistas estudiados los lácteosno representan una contribución tan importante a laenergía y nutrientes de su ingesta diaria como lo es parasus homólogos españoles del estudio enKid. Los cerealesson para ellos el grupo de alimentos que mas contribuye alaporte de energía, glúcidos y fibra, mientras que las carnesson el principal contribuyente al aporte de proteínas, grasastotales y grasas saturadas. De la misma forma que para losjóvenes españoles, el calcio procede principalmente de loslácteos y en menor medida de los cereales.Conclusiones: La dieta que sigue un porcentaje de los ciclistasjóvenes estudiados presenta desequilibrios nutricionales(consumo insuficiente de lácteos y excesivo de grasas yazúcares) que se deben corregir educando no solamente alos ciclistas, sino también a los padres y entrenadores(AU)

Introduction: The purpose of this study was to estimatemilk and dairies consumption in a group of young cyclistsin relation to recommendations and to compare the patternwith that prevailing in the homologous Spanish teenagersof the enKID study.Method: Dietary assessment in a cross-sectional observationalstudy design based on a seven day food diary in agroup of 47 young cyclists.Results: Daily milk products in this group of cyclists donot represent such important contribution to overall energyand nutrient intake as for Spanish teenagers according tothe enKID study. Cereals is the food group which mostcontributes to energy, carbohydrate and fiber intake. Meatis the food group that contributes the most to the intake ofprotein and fat. As observed in Spanish teenagers calciumis mainly supplied from daily milk products.Conclusion: An important percentage of this group of cyclistshow nutritional unbalances (inadequate consumption ofdaily milk products; excess intake of saturated fat andsugar). This should be modified by means of nutritioneducation actions targeted to the group but also to theircoaches and families(AU)