Increasing polymer usage has demanded functional additives that decrease fire hazards for end users. While traditional flame‐retardant (FR) additives, such as halogenated, phosphorus, and metal ...hydroxides, greatly reduce flammability and associated fire hazards, research has continually exposed a litany of health and environmental safety concerns. This perspective aims to identify the key components of a successful FR additive and address material, environmental, and health concerns of existing additives. Legislation surrounding FRs and persistent organic pollutants is also discussed to highlight political perception that has resulted in the increased chemical regulations and subsequent banning of FR additives. Finally, future directions of this field regarding nonreactive additives, focusing on the use of bioinspired materials and transition metal chemistries to produce alternatives for polymers with efficacies surpassing traditional additives are presented.
The article provides an overview of currently used nonreactive flame‐retardant additives and identifies their material, environmental, and health concerns. This article also draws attention to legislation surrounding flame‐retardant additives and discusses the implications of overgeneralized chemical bans. Finally, the future of environmentally more benign nonreactive flame‐retardant additives is highlighted, focusing on the use of biopolymers and transition metal chemistries.
Food and drug products contain diverse and abundant small-molecule additives (excipients) with unclear impacts on human physiology, drug safety, and response. Here, we evaluate their potential impact ...on intestinal drug absorption. By screening 136 unique compounds for inhibition of the key intestinal transporter OATP2B1 we identified and validated 24 potent OATP2B1 inhibitors, characterized by higher molecular weight and hydrophobicity compared to poor or noninhibitors. OATP2B1 inhibitors were also enriched for dyes, including 8 azo (R−N=N−R′) dyes. Pharmacokinetic studies in mice confirmed that FD&C Red No. 40, a common azo dye excipient and a potent inhibitor of OATP2B1, decreased the plasma level of the OATP2B1 substrate fexofenadine, suggesting that FD&C Red No. 40 has the potential to block drug absorption through OATP2B1 inhibition in vivo. However, the gut microbiomes of multiple unrelated healthy individuals as well as diverse human gut bacterial isolates were capable of inactivating the identified azo dye excipients, producing metabolites that no longer inhibit OATP2B1 transport. These results support a beneficial role for the microbiome in limiting the unintended effects of food and drug additives in the intestine and provide a framework for the data-driven selection of excipients. Furthermore, the ubiquity and genetic diversity of gut bacterial azoreductases coupled to experiments in conventionally raised and gnotobiotic mice suggest that variations in gut microbial community structure may be less important to consider relative to the high concentrations of azo dyes in food products, which have the potential to saturate gut bacterial enzymatic activity.
Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids ...exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN,
www.eurocaroten.eu
,
https://www.cost.eu/actions/CA15136/#tabs|Name:overview
) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.
Formamidinium lead triiodide (FAPbI3) is attractive for photovoltaic devices due to its optimal bandgap at around 1.45 eV and improved thermal stability compared with methylammonium‐based ...perovskites. Crystallization of phase‐pure α‐FAPbI3 conventionally requires high‐temperature thermal annealing at 150 °C whilst the obtained α‐FAPbI3 is metastable at room temperature. Here, aerosol‐assisted crystallization (AAC) is reported, which converts yellow δ‐FAPbI3 into black α‐FAPbI3 at only 100 °C using precursor solutions containing only lead iodide and formamidinium iodide with no chemical additives. The obtained α‐FAPbI3 exhibits remarkably enhanced stability compared to the 150 °C annealed counterparts, in combination with improvements in film crystallinity and photoluminescence yield. Using X‐ray diffraction, X‐ray scattering, and density functional theory simulation, it is identified that relaxation of residual tensile strains, achieved through the lower annealing temperature and post‐crystallization crystal growth during AAC, is the key factor that facilitates the formation of phase‐stable α‐FAPbI3. This overcomes the strain‐induced lattice expansion that is known to cause the metastability of α‐FAPbI3. Accordingly, pure FAPbI3 p–i–n solar cells are reported, facilitated by the low‐temperature (≤100 °C) AAC processing, which demonstrates increases of both power conversion efficiency and operational stability compared to devices fabricated using 150 °C annealed films.
An aerosol‐assisted crystallization method to prepare high‐quality, pure α‐FAPbI3 films at only 100 °C without chemical additives is reported. Remarkably improved phase stability of the α‐FAPbI3 films and their applications in solar cells are demonstrated. The overriding mechanism of stabilizing α‐FAPbI3 is shown to be relaxation of residual tensile strains in the films.
Nowadays, there is a great manufacturing trend in producing higher quality net-shape components of challenging geometries. One of the major challenges faced by additive manufacturing (AM) is the ...residual stresses generated during AM part fabrication often leading to unacceptable distortions and degradation of mechanical properties. Therefore, gaining insight into residual strain/stress distribution is essential for ensuring acceptable quality and performance of high-tech AM parts. This research is aimed at comparing microstructure and residual stress built-up in Ti–6Al–4V AM components produced by Wire+Arc Additive Manufacturing (WAAM) and by laser cladding process (CLAD).
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•The highest residual stress values are in longitudinal (deposition) direction•The maximum stress is observed in between baseplate and the deposited wall•CLAD sample show lower residual stress than WAAM sample•Both specimens exhibit columnar grains with finer wavy morphology in CLAD•Compressive stress is observed in different regions depending on the process
•The food industry uses silver nanoparticles as sensors, dietary supplements, additives, and in packaging.•They represent a potential risk of toxicity to the consumer, the intestinal tract and liver ...being their main targets.•Silver nanoparticles can produce free radicals and cause oxidative stress in cells, inducing oxidative damage.•Oxidative stress mediates toxicity by triggering inflammatory reactions and death by necrosis or apoptosis.
Because of their antimicrobial properties, the use of silver nanoparticles (AgNPs) is increasing fast in industry, food, and medicine. In the food industry, nanoparticles are used in packaging to enable better conservation products such as sensors to track their lifetime, and as food additives, such as anti-caking agents and clarifying agents for fruit juices. Nanoemulsions, used to encapsulate, protect and deliver additives are also actively developed. Nanomaterials in foods will be ingested and passed through the digestive tract. Those incorporated in food packaging may also be released unintentionally into food, ending up in the gastrointestinal tract. It is therefore important to make a risk assessment of nanomaterials to the consumer. Thus, exposure to AgNPs is increasing in quantity and it is imperative to know their adverse effects in man. However, controversies still remain with respect to their toxic effects and their mechanisms. Understanding the toxic effects and the interactions of AgNPs with biological systems is necessary to handle these nanoparticles and their use. They usually generate reactive oxygen species resulting in increased pro-inflammatory reactions and oxidative stress via intracellular signalling pathways. Here, we mainly focus on the routes of exposure of AgNPs, toxic effects and the mechanisms underlying the induced toxicity.
Extreme pressure (EP) and antiwear (AW) additives are necessary for boundary lubrication. However, their mechanisms and physical and chemical properties remain unclear. EP and AW additives were ...reviewed to fill gaps in theoretical and industrial applications. Compounds containing chlorine, sulfur, and phosphorus elements were first used in boundary lubrication because of thermal reaction with metal to form film characteristics. First, the mechanisms of traditional EP and AW additives were analyzed, the physical and chemical properties were compared, and properties affecting factors were studied. Traditional EP and AW additives are not environmentally friendly, but nanoparticle EP and AW additives are excellent substitutes. The mechanisms of nanoparticle EP and AW additives were summarized. The influence of nanoparticle structure parameters, concentration, and media polarity on properties was studied. Second, the influence law of non-polar chain length on traditional EP and AW additives was revealed. The improvement interval of traditional EP and AW additives on the performance of the base fluid was determined. The structural advantage of low crystallinity onion-like and multilayer sheet-like low wrinkle effect of nanoparticles was explained. The particle size design principle attached to the surface roughness and size-dependent melting inhibition mechanism was established. The influence of concentration and media polarity on nanoparticle properties was obtained. Finally, the research of minimum amount matching database and mathematical selection model for traditional EP and AW additives and the molecular dynamics analysis of surface-modified nanoparticles and the development of green general-purpose additives based on molecular design are prospected.
The female inflorescences of hops (Humulus lupulus L.), a well-known bittering agent used in the brewing industry, have long been used in traditional medicines. Xanthohumol (XN) is one of the ...bioactive substances contributing to its medical applications. Among foodstuffs XN is found primarily in beer and its natural occurrence is surveyed. In recent years, XN has received much attention for its biological effects. The present review describes the pharmacological aspects of XN and summarizes the most interesting findings obtained in the preclinical research related to this compound, including the pharmacological activity, the pharmacokinetics, and the safety of XN. Furthermore, the potential use of XN as a food additive considering its many positive biological effects is discussed.
In recent years, there has been an increasing demand in the commercial market to prolong the service life of engine oil. Oil contamination is one of the most important factors that influence ...friction, wear and which continuously accelerates oil degradation. The main contaminants in diesel engine oil are soot and water. The engine oil with a high level of soot causes an increase in oil drain interval to minimise the effect of hard soot particles on contact surfaces. Water is also a destructive contaminant that affects engine oil's physical and chemical stability. Many studies have been conducted on the effects of oil contaminants on oil performance, however the effects of oil contamination on additives and oil degradation are not fully understood yet. Engine oil additives have been widely used to enhance oil performance, reduce the effect of oil contamination and extend the lifespan of engine oil. Thus, the main focus of this study is to investigate the impact of soot and water on additives and the bulk oil and then replenish the influenced additives to regain the tribological performance of engine oil.
Titanium dioxide (TiO
2
) is widely used in pharmaceuticals preparations, cosmetics, and as a food additive (E171). It contains microparticles and a fraction of nanoparticles (NPs) which can be ...absorbed systemically by humans after ingestion. Increasing concern has been aroused about the impact of oral exposure to TiO
2
NPs from dietary and non-dietary sources on human health. In spite of several toxicological studies conducted in recent years, a solid risk assessment of oral exposure to E171 has not been satisfactorily achieved. We investigated whether repeated oral administration of E171 to mice at a dose level (5 mg/kg body weight for 3 days/week for 3 weeks) comparable to estimated human dietary exposure, results in TiO
2
deposition in the digestive system and internal organs, and in molecular and cellular alterations associated with an inflammatory response. To reproduce the first phase of digestion, a new administration approach involving the dripping of the E171 suspension into the mouth of mice was applied. Significant accumulation of titanium was observed in the liver and intestine of E171-fed mice; in the latter a threefold increase in the number of TiO
2
particles was also measured. Titanium accumulation in liver was associated with necroinflammatory foci containing tissue monocytes/macrophages. Three days after the last dose, increased superoxide production and inflammation were observed in the stomach and intestine. Overall, the present study indicates that the risk for human health associated with dietary exposure to E171 needs to be carefully considered.
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