Environmental aspects of the depreciation of the culturally significant Wall of Cartagena de Indias - Colombia

Among the diverse archeological relics of the past, the Cartagena de Indias Wall is one of the greatest representations of European cultural architecture in South America. To assess the implication of contamination on the depreciation of the culturally significant Wall of Cartagena de Indias - Colombia, a detailed, multi-analytical approach was conducted on components of the wall. Accumulated ultra-fine particles (UFPs) and superficial nano-particles (NPs) containing hazardous elements (HEs) on the wall were identified in an attempt to understand whether atmospheric pollution is hastening the depreciation of the structure itself. Mortar which at one point held the stones together is now weak and has fallen away in places. Irreparable damage is being done by salt spray, acid rain and the site's tropical humid climate. Several HEs and organic compounds found within the local environment are also contributing to the gradual deterioration of the construction. In this study, advanced microscopy analyses have been applied to understand the properties of UFPs and NPs deposited onto the wall's weathered external walls through exposure to atmospheric pollution. Several materials identified by X-Ray Diffraction (XRD) can be detected using high-resolution transmission electron microscopy (HR-TEM) and field emission scanning electron microscope (FE-SEM). The presence of anglesite, gypsum, hematite containing HEs, and several organic compounds modified due to moisture and contamination was found. Black crusts located on the structure could potentially serve as a source of HEs pollution and a probable hazard to not only to the ecosystem but also to human health.

Micro-Nanoscale Characteristics of Pyrite and Its Implications for Gold Mineralization: Two Cases of Gold Deposits in the Youjiang Basin and Southwestern Tianshan Mountains

The mineralogical and compositional characteristics of gold-bearing minerals and the occurrence of gold are not only of great significance to exploring the sources of ore-forming materials and their formation mechanisms but also helpful for designing reasonable beneficiations and smelting schemes and achieving remarkable economic benefits. This paper presents an integrated study on the crystal characteristics, elemental composition and distribution of pyrite (the main gold-bearing minerals), on the basis of electron probe microanalysis (EPMA), scanning electron microscopy (SEM), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and nano-secondary ion mass spectrometry (NanoSIMS). The occurrence of gold in the Shuiyindong gold deposit and Ashawayi gold deposit has been studied by means of microscopy, SEM, and EPMA images, elemental correlations, S-Fe-As ternary diagrams, logAs-logAu diagrams and Au/As ratios. The gold in pyrite of the Shuiyindong deposit is in the form of nano gold inclusions and lattice gold. The gold in pyrite of the Ashawayi deposit dominantly exists in the form of nano gold inclusions or is present as micro-nano gold particles in the cracks or edges of pyrite, some of which can exist as lattice gold. The ore-forming hydrothermal solution of the Shuiyindong gold deposit is mainly underground hot brine, but it may be reformed by a deep magmatic hydrothermal solution or volcanic-subvolcanic hydrothermal solution. The ore-forming hydrothermal solution of the Ashawayi gold deposit is mainly derived from the metamorphic hydrothermal solution formed during the orogenic process, and the ore-forming process or post-mineralization process may be reformed by the leaching of underground hot brine. Finally, the characteristics of ore-forming fluids and evolution of the two types of deposits are determined via pyrite element surface scanning. This paper shows that micro-nanoscale study of gold-bearing pyrite is of great significance to understanding the gold mineralization process and is worth further study.

Nanocolloids in drinking water increase the risk of obesity in mice by modulating gut microbes

Both gut microbes and environmental contamination may cause metabolic disorders and obesity. However, the relationships among gut microbes, environmental contamination and obesity remain obscure. The drinking water on a national scale (31 cities in China) contained nanocolloid-pattern contamination at the mg/L level, a concentration that is 10- to 100-fold higher than commonly reported pollutants. Exposure to nanocolloids (environmentally related dose, 0.15 mg/kg) for three weeks increased the body weight and leptin levels of mice and decreased the expression of adiponectin. Nanocolloids increased the ratio of Firmicutes to Bacteroidetes, a typical obesity-related phenomenon, in the obese individuals. Oral administration of resveratrol verified the role of gut microbes in the tendency toward obesity induced by nanocolloids. The ratio of Firmicutes to Bacteroidetes is positively correlated with body weight and leptin levels. Compared to the control, the levels of triglycerides and high-density lipoprotein cholesterol were up- and downregulated by the tested nanocolloids at 0.15 mg/kg, respectively. Long-chain fatty acids, lipid metabolites and the expression of lipid synthesis-related genes (Fas, Srebp-1 and ACC-1) were also significantly increased by nanocolloids. The present study provides new insights that improve our understanding the risks of obesity associated with drinking water contamination that are mediated by gut microbes.

Untargeted metabolomics for Achilles heel of engineered nanomaterials' risk assessment

Owing to the superlative properties, engineered nanomaterials (ENM) are being used in food, cosmetics, medicine, and electronics. Therefore, exogenous ENM can be housed into humans through a multitude of exposure routes, leading to compromise of the biomolecules' functionalities through structural deformations, and even at the metabolic level. Consequently, it is of great importance to understand the perturbations introduced at the metabolic level for the timely risk assessment (RA) of ENM. Current technological advancements in metabolomics empower us to visualize the metabolic dysregulations in biological cells, tissues, and living objects, instigated by the ENM. Given the fact, we propose multitiered untargeted metabolomics for the risk assessment of ENM. We propose largely validated experimental design principles that enable the well-organized and authentic identification of metabolic dysregulation connected with a newly engineered nanomaterial. Our scheme could participate in the enhanced transparency of the RA course of rapidly emerging ENM.

Insight into the structure–property relationship of UO2 nanoparticles

We show that the structural and electronic properties of UO₂ NPs (2–3 nm) are similar to those of bulk UO₂ under inert conditions, with U(iv) as the dominating oxidation state, though NPs oxidize with time and under the X-ray beam.

Effects of Ingested Nanomaterials on Tissue Distribution of Co-ingested Zinc and Iron in Normal and Zinc-Deficient Mice

Cellulose nanofibers (CNF) reduced serum triglyceride levels in rats when co-administered with heavy cream by gavage. Do CNF and other nanomaterials (NMs) alter the tissue distribution and retention of co-administered metal ions? We evaluated whether 5 different NMs affected tissue distribution of co-ingested 65Zn++ and 59Fe+++ in zinc-replete versus zinc-deficient mice. Male C57BL/6J mice were fed either zinc-replete or zinc-deficient diets for 3 weeks, followed by gavage with NM suspensions in water containing both 65ZnCl2 and 59FeCl3. Urine and feces were measured for 48 h post-gavage. Mice were euthanized and samples of 22 tissues were collected and analyzed for 65Zn and 59Fe in a gamma counter. Our data show that zinc deficiency alters the tissue distribution of 65Zn but not of 59Fe, indicating that zinc and iron homeostasis are regulated by distinct mechanisms. Among the tested NMs, soluble starch-coated chitosan nanoparticles, cellulose nanocrystals, and TiO2 reduced Zn and Fe tissue retention in zinc-deficient but not in zinc-replete animals.

Polyetheretherketone and Its Composites for Bone Replacement and Regeneration

In this article, recent advances in the development, preparation, biocompatibility and mechanical properties of polyetheretherketone (PEEK) and its composites for hard and soft tissue engineering are reviewed. PEEK has been widely employed for fabricating spinal fusions due to its radiolucency, chemical stability and superior sterilization resistance at high temperatures. PEEK can also be tailored into patient-specific implants for treating orbital and craniofacial defects in combination with additive manufacturing process. However, PEEK is bioinert, lacking osseointegration after implantation. Accordingly, several approaches including surface roughening, thin film coating technology, and addition of bioactive hydroxyapatite (HA) micro-/nanofillers have been adopted to improve osseointegration performance. The elastic modulus of PEEK is 3.7-4.0 GPa, being considerably lower than that of human cortical bone ranging from 7-30 GPa. Thus, PEEK is not stiff enough to sustain applied stress in load-bearing orthopedic implants. Therefore, HA micro-/nanofillers, continuous and discontinuous carbon fibers are incorporated into PEEK for enhancing its stiffness for load-bearing applications. Among these, carbon fibers are more effective than HA micro-/nanofillers in providing additional stiffness and load-bearing capabilities. In particular, the tensile properties of PEEK composite with 30wt% short carbon fibers resemble those of cortical bone. Hydrophobic PEEK shows no degradation behavior, thus hampering its use for making porous bone scaffolds. PEEK can be blended with hydrophilic polymers such as polyglycolic acid and polyvinyl alcohol to produce biodegradable scaffolds for bone tissue engineering applications.

Detection of nanoparticles by single-particle ICP-MS with complete transport efficiency through direct nebulization at few-microlitres-per-minute uptake rates

Measurement of nanoparticle (NP) concentration and size by single-particle inductively coupled plasma mass spectrometry (spICP-MS) usually requires the use of a NP reference material to determine the loss of NPs and/or ions during their transport from the sample solution to the detection system. The determination of this loss, qualified as nebulization efficiency (η_Nebulization) and/or transport efficiency (η_Transport), is time-consuming, costly and lacks reliability. Nebulization of the NPs directly into the plasma (without a spray chamber) results in η_Nebulization = 100% and is thus a promising strategy to avoid these calibration steps. In this work, we used the μ-dDIHEN introduction system: a demountable direct injection high-efficiency nebulizer (dDIHEN) hyphenated to a flow-injection valve and a gas displacement pump. For the first time with a continuous flow nebulizer, complete transport efficiency was reached (i.e. η_Transport = 100%). Operated at a very low uptake rate (as low as 8 μL min^-1), the μ-dDIHEN accurately and reproducibly determined average diameters of Au-, Ag- and Pt-NPs, in full agreement with their reference values. It was also successfully tested for Au-NPs in complex matrices, such as surface waters. spICP-MS analyses with the μ-dDIHEN sample introduction system only require a dissolved standard calibration to determine NP average diameter (d_NPs in nm) and number concentration (N_NPs) from the simplified set of equations: [Formula: see text] and [Formula: see text]Graphical abstract.

Copper nanowires as nanofertilizers for alfalfa plants: Understanding nano-bio systems interactions from microbial genomics, plant molecular responses and spectroscopic studies

The recent application of nano copper (Cu) compounds in the agrosystem has shown potential to improve the physiological performance and agronomical parameters of crops. We grew alfalfa (Medicago sativa) in potting mix amended with bulk, nano, and ionic Cu compounds at 80 and 280 mg Cu/kg; then, we evaluated plant performance at physiological and molecular levels. Plants treated with bulk/nano Cu presented better agronomical responses. The P and S content was reduced in bulk and ionic Cu-exposed plants, compared to controls (p ≤ .05). All Cu forms increased the content of Fe and Zn in roots and Fe in leaves, compared to controls (p ≤ .05). Leaf-superoxide dismutase expression was augmented ~27-fold and rubisco mRNA was unaffected in bulk/nano Cu-treated plants, compared to controls (p ≤ .05). Bulk/nano Cu incremented the relative abundance of microorganisms involved in the elemental uptake. These results indicate that nano Cu improved the physiology of alfalfa and can be considered as potential nanofertilizers.

Combined toxicity of functionalized nano-carbon black and cadmium on Eisenia fetida coelomocytes: The role of adsorption

Little is known about the potential threats of functionalized nano-carbon black (FNCB) combined with cadmium (Cd) to soil invertebrates. In this study, immunocompetent coelomocytes from Eisenia fetida are harnessed, and the joint cytotoxicity types of FNCB and Cd co-exposure are analyzed. The extracellular interaction mechanisms of FNCB and Cd were completely explored using adsorption kinetics and thermodynamics accompanied by isotherm batch experiments and Fourier infrared spectroscopy. The results indicated that functional amorphous carbon nanoparticles up to certain dose may injure cells due to their surface oxygen-containing groups. The MIXTOX model and the combination index suggested that the combined action of FNCB and Cd exhibited antagonism at the low dose/effect-level and synergism at the high dose/effect-level. FNCB decreased the intracellular free Cd²⁺ content at a low mixture dose, while it increased it at a high mixture dose. The adsorption of Cd on FNCB followed pseudo-second-kinetics and the Langmuir isotherm, hence better indicating a chemisorption, which was also supported by the activation energy (E_a = 36.6 kJ/mol), enthalpy change (ΔH = -98.4 kJ/mol), and functional group changes. Coordination binding should be responsible for the subsequent interaction of toxicity.

Exposure of CuO nanoparticles and their metal counterpart leads to change in the gut microbiota and resistome of collembolans

The widespread use of copper oxide nanoparticles (CuONPs) has dramatically increased their concentrations in soils and severely affected the health of soil organisms. The gut microbiota critically contributes to the metabolism and immune system of its host and is sensitive to environmental pollution. The toxic effect of CuONPs on the gut microbiota, especially in soil fauna, still needs further research. In the present study, a comprehensive toxicological test was performed to reveal the effects of CuONPs and their metal counterpart on the gut microbiota of soil collembolans using Illumina high throughput sequencing. Furthermore, the concomitant changes in the collembolans gut-associated antibiotic resistance genes (ARGs) and metabolism were investigated using high-throughput quantitative PCR and carbon and nitrogen stable isotope compositions. Both CuONPs and ionic copper (Cu) exposure disturbed the collembolan gut microbial community structure while only CuONPs reduced the gut microbial diversity. A total of 66 ARGs were detected in the collembolan guts, and CuONPs exposure induced a reduction in both diversity and abundance of ARGs. Additionally, CuONPs and ionic Cu exposure altered the C and N stable isotope compositions of the collembolans, indicating a change in their metabolism. Moreover, structural equation modeling indicated that 85.5% of the carbon stable isotope variations and 73.3% of the nitrogen stable isotope variations were explained by changes in Cu bioaccumulation and the gut microbiota. The results of the present study extend our knowledge regarding the comprehensive toxicity of metal oxide NPs on soil fauna.

Heterogenous Internalization of Nanoparticles at Ultra-Trace Concentration in Environmental Individual Unicellular Organisms Unveiled by Single-Cell Mass Cytometry

The application and consumption of nanoparticles (NPs) inevitably result in the contamination of environmental water. The internalized NPs in unicellular organisms could travel to human bodies along food chains and raise health concerns. Current research failed to determine the characteristics of cellular uptake of NPs by unicellular organisms at extremely low concentration in the real environment. We here developed a label-free high-throughput mass cytometry method to investigate gold NP (AuNP) uptake in a unicellular organism (Tetrahymena thermophila) at the single-cell level. The limit of detection for Au is as low as to 6.67 × 10^-18 g/cell, which equals ∼5.3 5 nm AuNPs. We demonstrated that active engulfment pathways were responsible for the cellular accumulation of AuNPs and T. thermophila could also eliminate the cellular AuNPs rapidly. The interaction between AuNPs and T. thermophila is highly dependent on the sizes of nanoparticles; i.e., the population of T. thermophila containing AuNPs decreased with the increment of the diameters of AuNPs when exposed to the same mass concentration. For each type of AuNP, distinct heterogeneous cellular uptake of AuNPs by T. thermophila was observed. Intriguingly, for 5 nm AuNP, even at 0.001 ng/mL, some T. thermophila cells could concentrate AuNPs, indicating a real environmental concern even when water was contaminated by only trace level of NPs. This method represents a promising tool for simultaneous determination of physiological status of cells together with the intracellular level of heavy metal or metallic NPs in study of biological effects.

Molecular dynamics simulations of the colloidal interaction between smectite clay nanoparticles in liquid water

Colloidal interactions between clay nanoparticles have been studied extensively because of their strong influence on the hydrology and mechanics of many soils and sedimentary media. The predominant theory used to describe these interactions is the Derjaguin-Landau-Verwey-Overbeek (DLVO) model, a framework widely applied in colloidal and interfacial science that accurately predicts the interactions between charged surfaces across water films at distances greater than ~ 3 nm (i.e., ten water monolayers). Unfortunately, the DLVO model is inaccurate at the shorter interparticle distances that predominate in most subsurface environments. For example, it inherently cannot predict the existence of equilibrium states wherein clay particles adopt interparticle distances equal to the thickness of one, two, or three water monolayers. Molecular dynamics (MD) simulations have the potential to provide detailed information on the free energy of interaction between clay nanoparticles; however, they have only been used to examine clay swelling and aggregation at interparticle distances below 1 nm. We present the first MD simulation predictions of the free energy of interaction of smectite clay nanoparticles in the entire range of interparticle distances from the large interparticle distances where the DLVO model is accurate (>3 nm) to the short-range swelling states where non-DLVO interactions predominate (<1 nm). Our simulations examine a range of salinities (0.0 to 1.0 M NaCl) and counterion types (Na, K, Ca) and establish a detailed picture of the breakdown of the DLVO model. In particular, they confirm previous theoretical suggestions of the existence of a strong non-DLVO attraction with a range of ~ 3 nm arising from specific ion-clay Coulomb interactions in the electrical double layer.

Fungus Aspergillus niger Processes Exogenous Zinc Nanoparticles into a Biogenic Oxalate Mineral

Zinc oxide nanoparticles (ZnO NPs) belong to the most widely used nanoparticles in both commercial products and industrial applications. Hence, they are frequently released into the environment. Soil fungi can affect the mobilization of zinc from ZnO NPs in soils, and thus they can heavily influence the mobility and bioavailability of zinc there. Therefore, ubiquitous soil fungus Aspergillus niger was selected as a test organism to evaluate the fungal interaction with ZnO NPs. As anticipated, the A. niger strain significantly affected the stability of particulate forms of ZnO due to the acidification of its environment. The influence of ZnO NPs on fungus was compared to the aqueous Zn cations and to bulk ZnO as well. Bulk ZnO had the least effect on fungal growth, while the response of A. niger to ZnO NPs was comparable with ionic zinc. Our results have shown that soil fungus can efficiently bioaccumulate Zn that was bioextracted from ZnO. Furthermore, it influences Zn bioavailability to plants by ZnO NPs transformation to stable biogenic minerals. Hence, a newly formed biogenic mineral phase of zinc oxalate was identified after the experiment with A. niger strain’s extracellular metabolites highlighting the fungal significance in zinc biogeochemistry.

Susceptibility Factors in Chronic Lung Inflammatory Responses to Engineered Nanomaterials

Engineered nanomaterials (ENMs) are products of the emerging nanotechnology industry and many different types of ENMs have been shown to cause chronic inflammation in the lungs of rodents after inhalation exposure, suggesting a risk to human health. Due to the increasing demand and use of ENMs in a variety of products, a careful evaluation of the risks to human health is urgently needed. An assessment of the immunotoxicity of ENMs should consider susceptibility factors including sex, pre-existing diseases, deficiency of specific genes encoding proteins involved in the innate or adaptive immune response, and co-exposures to other chemicals. This review will address evidence from experimental animal models that highlights some important issues of susceptibility to chronic lung inflammation and systemic immune dysfunction after pulmonary exposure to ENMs.

Chiral Nanoceramics

The study of different chiral inorganic nanomaterials has been experiencing rapid growth during the past decade, with its primary focus on metals and semiconductors. Ceramic materials can substantially expand the range of mechanical, optical, chemical, electrical, magnetic, and biological properties of chiral nanostructures, further stimulating theoretical, synthetic, and applied research in this area. An ever-expanding toolbox of nanoscale engineering and self-organization provides a chirality-based methodology for engineering of hierarchically organized ceramic materials. However, fundamental discoveries and technological translations of chiral nanoceramics have received substantially smaller attention than counterparts from metals and semiconductors. Findings in this research area are scattered over a variety of sources and subfields. Here, the diversity of chemistries, geometries, and properties found in chiral ceramic nanostructures are summarized. They represent a compelling materials platform for realization of chirality transfer through multiple scales that can result in new forms of ceramic materials. Multiscale chiral geometries and the structural versatility of nanoceramics are complemented by their high chiroptical activity, enantioselectivity, catalytic activity, and biocompatibility. Future development in this field is likely to encompass chiral synthesis, biomedical applications, and optical/electronic devices. The implementation of computationally designed chiral nanoceramics for biomimetic catalysts and quantum information devices may also be expected.

Detection, occurrence, and fate of emerging contaminants in agricultural environments (2020)

A review of 79 papers published in 2019 is presented. The topics ranged from detailed descriptions of analytical methods, to fate and occurrence studies, to ecological effects and sampling techniques for a wide variety of emerging contaminants likely to occur in agricultural environments. New methods and studies on veterinary pharmaceuticals, antibiotics, anthelmintics, and engineered nanomaterials in agricultural environments continue to expand our knowledge base on the occurrence and potential impacts of these compounds. This review is divided into the following sections: Introduction, Analytical Methods, Antibiotics in Agroecosystems, Pharmaceutical Fate and Occurrence, Anthelmintics and Engineered Nanomaterials. PRACTITIONER POINTS: New research describes innovative new techniques for emerging contaminant detection in agricultural settings Newer classes of contaminants include human and veterinary pharmaceuticals Research in nanomaterials show that these also occur in agricultural environments and will likely be topics of future work.

Sulfur Species, Bonding Environment, and Metal Mobilization in Mining-Impacted Lake Sediments: Column Experiments Replicating Seasonal Anoxia and Deposition of Algal Detritus

The oxidation state of sulfur [S] is a primary control on mobility of metals in sediments impacted by legacy mining practices. Coeur d’Alene Lake of northern Idaho, USA, has been impacted by upstream legacy mining practices that deposited an estimated 75 Mt of metal(loid)- and S-rich sediments into the lake. Future lake conditions are expected to include algal blooms, which may alter S and metal remobilization during the seasonal euxinic environment. Cores of the lake sediments were exposed to anoxic and anoxic + algal detritus conditions for eight weeks at 4.5 °C through introduction of a N2 atmosphere and addition of algal detritus. At a location 2.5 cm below the sediment-water interface, anoxic conditions promoted a shift in S species to continually larger concentrations of reduced species and an associated shift in the bonding environment reflective of increased S–metal bonds. Anoxic + algal detritus conditions suppressed the increasing trend of reduced S species and induced greater release of Mn compared to the anoxic-only conditions but did not appear to enhance the release of As, Cd, or Fe. The addition of algal detritus to the sediment-water interface of these Fe- and S-rich sediments enhanced mobilization of Mn likely because of dissimilatory metal reduction where the anaerobic oxidation of the algal detritus stimulated Mn reduction. Results of the study indicate that future metal release from the lake sediments will be altered with the likely deposition of algal detritus, but the effect may not enhance the release of acutely toxic metals, such as As or Cd, or substantially impact Fe cycling in the sediments.

Interfacial water and ion distribution determine ζ potential and binding affinity of nanoparticles to biomolecules

The molecular features that dictate interactions between functionalized nanoparticles and biomolecules are not well understood. This is in part because for highly charged nanoparticles in solution, establishing a clear connection between the molecular features of surface ligands and common experimental observables such as ζ potential requires going beyond the classical models based on continuum and mean field models. Motivated by these considerations, molecular dynamics simulations are used to probe the electrostatic properties of functionalized gold nanoparticles and their interaction with a charged peptide in salt solutions. Counterions are observed to screen the bare ligand charge to a significant degree even at the moderate salt concentration of 50 mM. As a result, the apparent charge density and ζ potential are largely insensitive to the bare ligand charge densities, which fall in the range of ligand densities typically measured experimentally for gold nanoparticles. While this screening effect was predicted by classical models such as the Manning condensation theory, the magnitudes of the apparent surface charge from microscopic simulations and mean-field models are significantly different. Moreover, our simulations found that the chemical features of the surface ligand (e.g., primary vs. quaternary amines, heterogeneous ligand lengths) modulate the interfacial ion and water distributions and therefore the interfacial potential. The importance of interfacial water is further highlighted by the observation that introducing a fraction of hydrophobic ligands enhances the strength of electrostatic binding of the charged peptide. Finally, the simulations highlight that the electric double layer is perturbed upon binding interactions. As a result, it is the bare charge density rather than the apparent charge density or ζ potential that better correlates with binding affinity of the nanoparticle to a charged peptide. Overall, our study highlights the importance of molecular features of the nanoparticle/water interface and underscores a set of design rules for the modulation of electrostatic driven interactions at nano/bio interfaces.

Intrinsic enzyme-like activity of magnetite particles is enhanced by cultivation with Trichoderma guizhouense

Fungal-mineral interactions can produce large amounts of biogenic nano-size (~ 1-100 nm) minerals, yet their influence on fungal physiology and growth remains largely unexplored. Using Trichoderma guizhouense NJAU4742 and magnetite (Mt) as a model fungus and mineral system, we have shown for the first time that biogenic Mt nanoparticles formed during fungal-mineral cultivation exhibit intrinsic peroxidase-like activity. Specifically, the average peroxidase-like activity of Mt nanoparticles after 72 h cultivation was ~ 2.4 times higher than that of the original Mt. Evidence from high resolution X-ray photoelectron spectroscopy analyses indicated that the unique properties of magnetite nanoparticles largely stemmed from their high proportion of surface non-lattice oxygen, through occupying surface oxygen-vacant sites, rather than Fe redox chemistry, which challenges conventional Fenton reaction theories that assume iron to be the sole redox-active centre. Nanoscale secondary ion mass spectrometry with a resolution down to 50 nm demonstrated that a thin (< 1 μm) oxygen-film was present on the surface of fungal hyphae. Furthermore, synchrotron radiation-based micro-FTIR spectra revealed that surface oxygen groups corresponded mainly to organic OH, mineral OH and carbonyl groups. Together, these findings highlight an important, but unrecognized, catalytic activity of mineral nanoparticles produced by fungal-mineral interactions and contribute substantially to our understanding of mineral nanoparticles in natural ecosystems.

Automation and low-cost proteomics for characterization of the protein corona: experimental methods for big data

Nanoparticles used in biological settings are exposed to proteins that adsorb on the surface forming a protein corona. These adsorbed proteins dictate the subsequent cellular response. A major challenge has been predicting what proteins will adsorb on a given nanoparticle surface. Instead, each new nanoparticle and nanoparticle modification must be tested experimentally to determine what proteins adsorb on the surface. We propose that any future predictive ability will depend on large datasets of protein-nanoparticle interactions. As a first step towards this goal, we have developed an automated workflow using a liquid handling robot to form and isolate protein coronas. As this workflow depends on magnetic separation steps, we test the ability to embed magnetic nanoparticles within a protein nanoparticle. These experiments demonstrate that magnetic separation could be used for any type of nanoparticle in which a magnetic core can be embedded. Higher-throughput corona characterization will also require lower-cost approaches to proteomics. We report a comparison of fast, low-cost, and standard, slower, higher-cost liquid chromatography coupled with mass spectrometry to identify the protein corona. These methods will provide a step forward in the acquisition of the large datasets necessary to predict nanoparticle-protein interactions.

Fabrication and Applications of 3D Nanoarchitectures for Advanced Electrocatalysts and Sensors

For the last few decades, nanoscale materials and structures have been extensively studied and developed, making a huge impact on human sustainability. For example, the introduction of nanostructures has brought substantial development in electrocatalysts and optical sensing applications. However, there are still remaining challenges that need to be resolved to further improve their performance, reliability, and cost-effectiveness. Herein, long-range ordered 3D nanostructures and their design principles are introduced with an emphasis on electrocatalysts for energy conversion and plasmonic nanostructures for optical sensing. Among the various fabrication techniques, sequential solvent-injection-assisted nanotransfer printing is suggested as a practical fabrication platform for tunable long-range ordered 3D nanostructures composed of ultrahigh-resolution building blocks. Furthermore, the importance of understanding and controlling the 3D design parameters is discussed to realize more efficient energy conversion as well as effective surface-enhanced Raman spectroscopy analyses, suggesting new solutions for clean energy and healthcare issues.

Bioaccumulation of ytterbium oxide nanoparticles insinuate oxidative stress, inflammatory, and pathological lesions in ICR mice

With the rapid development in nanoscience and nanotechnology, rare earth oxide nanomaterials (REO-NMs) have been increasingly used due to their unique physical and chemical characteristics. Despite the increasing applications of REO NPs, scarce information is available on their detrimental effects. In the current study, we investigate the toxic effect of ytterbium oxide nanoparticles (Yb₂O₃ NPs) in mouse model by using various techniques including inductively coupled plasma mass spectrometry (ICP-MS) analysis over 30 days of exposure. Furthermore, we elucidated lung lavage fluid of mice for biochemical and cytological analysis, and lung tissues for histopathology to interpret the NP side effects. We observed a significant concentration of Yb₂O₃ NPs accumulated in the lung, liver, kidney, and heart tissues. Similarly, increased bioaccumulation of Yb content was found in the olfactory bulb compared to other reigns of brain. The cytological analysis of bronchoalveolar lavage fluid (BALF) revealed a significant elevation in the percentage of neutrophils and lymphocytes. Biochemical analysis showed an instilled Yb₂O₃ NPs, showing signs of oxidative damage through up-regulation of 60-87% of MDA while down-regulation of 20-40% of GSH-PX and GSH content. The toxicity pattern was more evident from histopathological observations. These interpretations provide enough evidence of bioaccumulation of Yb₂O₃ NPs in mice tissues. Overall, our findings reveal that acute exposure of Yb₂O₃ NPs through intranasal inhalation may cause toxicity via oxidative stress, which leads to a chronic inflammatory response. Graphical abstract Graphical illustrations of experimental findings.

Antibiotic resistance genes (ARGs) and their associated environmental factors in the Yangtze Estuary, China: From inlet to outlet

The occurrence of antibiotic resistance genes (ARGs) and their associated environmental factors in estuaries are poorly understood. In this study, we comprehensively analyzed ARGs in both water and sediments from inlet to outlet of the Yangtze Estuary, China. The relative abundances of ARGs were higher in the turbidity maximum zone (TMZ) than other sites, implying that suspended particulate matter (SPM) was the major reservoir for ARGs in water. ARGs showed an increasing trend from inlet to outlet in sediments. Positively correlation between intI1 and sul1 in both water and sediments indicated that sul1 may be regulated by intI1. Correlation analysis and redundancy analysis showed that the spatial variations of estuarine ARGs were positively correlated with sample properties (e.g., temperature, SPM, pH) and chemical pollutants (e.g., heavy metals and antibiotic residues), among which chemical pollutants were the major drivers for the ARG distribution in both water and sediments.

Nanoparticle Toxicology

Nanoparticles from natural and anthropogenic sources are abundant in the environment, thus human exposure to nanoparticles is inevitable. Due to this constant exposure, it is critically important to understand the potential acute and chronic adverse effects that nanoparticles may cause to humans. In this review, we explore and highlight the current state of nanotoxicology research with a focus on mechanistic understanding of nanoparticle toxicity at organ, tissue, cell, and biomolecular levels. We discuss nanotoxicity mechanisms, including generation of reactive oxygen species, nanoparticle disintegration, modulation of cell signaling pathways, protein corona formation, and poly(ethylene glycol)-mediated immunogenicity. We conclude with a perspective on potential approaches to advance current understanding of nanoparticle toxicity. Such improved understanding may lead to mitigation strategies that could enable safe application of nanoparticles in humans. Advances in nanotoxicity research will ultimately inform efforts to establish standardized regulatory frameworks with the goal of fully exploiting the potential of nanotechnology while minimizing harm to humans.

Insights into the effect of cerium oxide nanoparticle on microalgal degradation of sulfonamides

Nanoparticles have been commercially used worldwide; however, there is a lack of information of their environmental impacts and ecotoxicity. In this study, the effect of cerium oxide nanoparticle (CeO₂NP) on a green microalga Scenedesmus obliquus, and microalgal biodegradation of four sulfonamides (sulfamethazine, sulfamethoxazole, sulfadiazine, and sulfamethoxazole) was investigated. There is insignificant inhibition of microalgal growth induced by CeO₂NP; however, it substantially influenced the expression of genes involved in key cellular metabolic activities of S. obliquus. For example, genes involved in photosynthetic activity (psbA) and energy production (ATPF0C) were downregulated with exposure to CeO₂NP. The low concentrations of CeO₂NP improved microalgal degradation of sulfonamides. This may be because of the upregulated genes encoding hydrogenase and oxidoreductase. The exploration of this study has provided a new understanding of the environmental impacts of CeO₂NP on microalgae-based biotechnologies for treatment of wastewater containing emerging organic contaminants.

Size Fractionation of Titania Nanoparticles in Wild Dittrichia viscosa Grown in a Native Environment

We report a size fractionation of titania (TiO₂) nanoparticles absorbed from the environment and found within wild Dittrichia viscosa plants. The nanoparticles were isolated by extraction and isolation from distinct plant organs, as well as from the corresponding rhizosphere of wild, adult plants. The collected nanoparticles were characterized by scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy (STEM-EDS). More than 1200 TiO₂ nanoparticles were analyzed by these techniques. The results indicated the presence of TiO₂ nanoparticles with a wide range of sizes within the inspected plant organs and rhizospheres. Interestingly, a size selective process occurs during the internalization and translocation of these nanoparticles (e.g., foliar and root uptake), which favors the accumulation of mainly TiO₂ nanoparticles with diameters <50 nm in the leaves, stems, and roots. In fact, our findings indicate that among the total number of TiO₂ nanoparticles analyzed, the fraction of the particles with dimensions <50 nm were 52% of those within the rhizospheres, 88.5% of those within the roots, 90% of those within the stems, and 53% of those within the leaves. This significant difference observed in the size distribution of the TiO₂ nanoparticles among the rhizosphere and the plant organs could have impacts on the food chain and further biologicals effects that are dependent on the size of the TiO₂.

Enhanced Hydrolysis of p-Nitrophenyl Phosphate by Iron (Hydr)oxide Nanoparticles: Roles of Exposed Facets

Iron (hydr)oxide nanoparticles are one of the most abundant classes of naturally occurring nanoparticles and are widely used engineered nanomaterials. In the environment these nanoparticles may significantly affect contaminant fate. Using two goethite materials with different contents of exposed {021} facet and two hematite materials with predominantly exposed {001} and {100} facets, respectively, we show that exposed facets, one of the most intrinsic properties of nanocrystals, significantly affect the efficiency of iron (hydr)oxide nanoparticles in catalyzing acid-promoted hydrolysis of 4-nitrophenyl phosphate (pNPP, selected as a model organophosphorus pollutant). Attenuated total reflectance Fourier-transform infrared spectroscopy analysis and density functional theory calculations indicate that the pNPP hydrolysis reaction on the iron (hydr)oxide surface involves the inner-sphere complexation between the phosphonate moiety of pNPP and the surface ferric iron (Fe(III)), through ligand exchange with primarily the singly coordinated surface hydroxyl groups of iron (hydr)oxides. Both the abundance and affinity of these adsorption sites are facet-dependent. Exposed facets also determine the reaction kinetics of surface-bound pNPP mainly by regulating the Lewis acidity of the surface Fe(III) atoms. These findings underline the important roles of facets in determining the reactivity of naturally occurring metal-based nanoparticles toward environmental contaminants and may shed light on the development of nanomaterial-based remediation strategies.

Facet-Dependent Adsorption and Fractionation of Natural Organic Matter on Crystalline Metal Oxide Nanoparticles

Natural organic matter (NOM) and crystalline metal oxide nanoparticles are both prevalent in natural aquatic environments, and their interactions have important environmental and biogeochemical implications. Here, we show that these interactions are significantly affected by an intrinsic property of metal oxide nanocrystals, the exposed facets. Both anatase (TiO₂) and hematite (α-Fe₂O₃) nanocrystals, representing common engineered and naturally occurring metal oxides, exhibited apparent facet-dependent adsorption of humic acid and fulvic acid. This facet-dependent binding was primarily driven by surface complexation between the NOM carboxyl groups and surficial metal atoms. Thus, the adsorption affinity of different-faceted nanocrystals was determined by the atomic arrangements of crystal facets that controlled the activity of metal atoms and, consequently, the ligand exchange and binding configuration of the carboxyl groups in the first hydration shell of nanocrystals. Distinct facet-dependent fractionation patterns were observed during adsorption of NOM components, particularly the low-molecular-weight and photorefractory constituents. The molecular fractionation of NOM between water and metal oxide nanoparticles was dictated by the combined effects of facet-dependent metal complexation, hydrophobic interaction, and steric hindrance and may significantly influence the NOM-driven processes occurring both in aqueous phases and at water-nanoparticle interfaces.

Citrate Controls Fe(II)-Catalyzed Transformation of Ferrihydrite by Complexation of the Labile Fe(III) Intermediate

Ferrihydrite (Fh) is generally associated with dissolved organic matter (DOM) in natural environments due to a strong sorption affinity at circumneutral pH and its high specific surface area. In suboxic conditions, aqueous Fe(II) (Fe(II)_aq) can catalyze transformation of Fh into more stable crystalline Fe(III) phases, but how DOM influences the transformation kinetics and pathway is still unclear. Using citrate as a surrogate, we have examined Fh transformation with 1 mM Fe(II)_aq and 0-60 μM citrate at pH 7.2. We focus on quantifying the time-dependent concentrations of sorbed Fe(II), structural Fe(II), and a key intermediate species, labile Fe(III) (Fe(III)_labile), resulting from interfacial electron transfer (IET), and how these species correlate with the evolution of lepidocrocite (Lp), magnetite (Mt), and goethite (Gt) products. Low concentrations of citrate significantly impact the proportions of Lp/Gt, and the collective results reveal that its effect is primarily through its ability to complex labile Fe(III) and thereby disrupt polymerization into product crystallites, as opposed to modifying the surface properties of Fh or inhibiting IET. The emergence of a Mt coprecipitate is observed in the transformation experiments with 5-10 μM citrate, when the Fe(II)/Fe(III)_labile ratio on/near the Fh surface is close to 0.5, the stoichiometric Fe(II)/Fe(III) ratio in Mt. At the molecular level, the findings suggest that citrate, and by extension DOM, can modify the relative rates of olation and oxolation reactions that assemble labile Fe(III) into various product minerals.

Seasonal formation and stability of dissolved metal particles in mining-impacted, lacustrine sediments

Formation of dissolved metal particles (<450 nm) in mining-impacted environments is a concern because of their potential for greater mobility and ecotoxicity compared to free ion and(or) sediment-bound metals. Metal-contaminated environments may produce soluble metal(loid) particles whose stability and transportability are determined by environmental conditions and particle composition. The Coeur d'Alene River Basin of northern Idaho, USA, is impacted by legacy mine waste-estimated 56 million tonnes of waste rock containing 900,000 t of Pb and 700,000 t of Zn were discharged into the Coeur d'Alene River and its tributaries during mining of argentiferous galena-sphalerite deposits. These legacy disposal practices resulted in substantial metal contamination-including As, Cd, Fe, Pb, Mn, and Zn-of floodplain sediments. Monthly lakewater samples and sediment cores were collected along the shoreline of a metal-contaminated lateral lake of the Coeur d'Alene River. Porewater was extracted from upper and lower sediments to evaluate the formation and stability of dissolved metal particles during seasonal changes. Substantial concentrations of Fe, Pb, Mn, and Zn were present in 450-nm filtered porewater during each month, with variable increases and decreases of metal concentrations in filtered lakewater according to seasonal changes. Dissolved metal particles with an average diameter of 180 ± 115 nm were present in the porewater of the upper and lower sediments with size increases in early spring and decreases in fall. Particles in the lower sediment porewater were typically more stable, as indicated by more negative ζ potential values, and the greatest particle stability occurred during summer. Differences between upper and lower porewater metal particles correspond to changes in sediment S speciation and bond relocation resulting from an input of oxygenated groundwater. Transport of the dissolved metal particles in and from the sediments likely occurs with a change in the hydraulic gradient during a spring-to-summer transition that induces redox changes and increases particle stability. The presence of mining-related minerals and seasonal changes in environmental conditions allow for formation of dissolved metal particles, but the limited stability of the particles and/or low permeability of the sediments appear to limit, but not fully restrict, possible transport of metal particles to the overlying lakewater.

Insights into spatial effects of ceria nanoparticles on oxygen mass transfer in wastewater biofilms: Interfacial microstructure, in-situ microbial activity and metabolism regulation mechanism

Growing international exploitation of ceria nanoparticles (CeO₂ NPs) for varied applications has increased their release into wastewater treatment plants. Mass transfer of oxygen (MTO) in wastewater biofilm is of considerable importance to influence the activity and purification ability of biofilm. Herein, we investigated the spatial distribution of oxygen in gas-liquid-biofilm phases, the microstructure of interfaces and the in-situ microbial activity to reveal the impacts of CeO₂ NPs on MTO in wastewater biofilm and the related mechanisms. After exposure to 1 and 10 mg/L CeO₂ NPs, the oxygen transfer coefficient (K_La) from gas to wastewater increased by 28.1% and 75.3% with a reduction of thickness in gas-liquid boundary layer, indicating the enhanced MTO in gas-liquid interface. In contrast, the MTO in liquid-biofilm interface was negatively affected and the thickness of liquid-biofilms boundary layer significantly increased, which was mainly attributed to the smoother surface and the decreased surface area difference of biofilm. Within biofilm, the microbial activity was inhibited by 10 mg/L CeO₂ NPs, whereas the production of extracellular polymeric substance (EPS) was significantly improved, leading to a decline of 35.0% in the internal effective diffusivity (D_B) and a 300-μm reduction of oxygen penetration depth. Moreover, the relative activities of key enzymes involved in glycometabolism indicated the transition of Embden-Meyerhof pathway to pentose phosphate pathway, which probably contributed to the enhanced EPS production and consequently increased mass transfer resistance in liquid-biofilm interface and inner biofilm. These results could potentially expand the knowledge on mass transfer of nutrients or pollutants in wastewater biofilm in response to NPs exposure.

Developing Nano-Delivery Systems for Agriculture and Food Applications with Nature-Derived Polymers

The applications of nanotechnology are wide ranging, and developing functional nanomaterials for agri-food applications from nature-derived polymers is widely conceived as a sustainable approach that is safer for human and animal consumption. In light of this, this review focuses on the advances in the development of nano-delivery systems using nature-derived polymers for agri-food applications. The review opens with a section detailing the different types of nature-derived polymers currently being used in various applications in the agri-food industry with a special mention on microbial extracellular polymeric materials. The major applications of nano-delivery systems in the food sector, such as food fortification and food preservation, as well as in the agricultural sector for controlled release of agrochemicals using nature-derived polymers are discussed. The review ends with a perspective on the safety and public perception of nano-enabled foods with a concluding remark on future directions of incorporating nano-delivery systems for agri-food purposes.

Identification of protein-polysaccharide nanoparticles carrying hepatoprotective bioactives in freshwater clam (Corbicula fluminea Muller) soup

Bioactives can impact food function either by their dosage or by their forms of dispersion, though the latter remains mostly neglected. Here we report the incidental nanoparticles (iNPs) carrying hepatoprotective bioactives identified in freshwater clam (Corbicula fluminea Muller) soup, which is a folk remedy for liver conditions in East Asia. The soup was fractionated into two iNPs containing fractions with high yield (95.8%) in 35 min by gel chromatography. With hydrodynamic diameter (D_h) range from 40 nm to 149 nm, iNPs were mainly constituted by carbohydrates and proteins. Notably, the majority of bioactives, e.g. taurine (63.2%), ornithine (68.1%) and phytosterols (60.0%), was determined to be carried by the iNPs. It suggested a possible mechanism of elevated delivery and absorption of bioactives, explaining why the clam soup can work at the bioactive concentrations way lower than the individual compound. These iNPs have great potential to be developed into a functional food with most potent nutraceutical effects.

Impacts of Proteins on Dissolution and Sulfidation of Silver Nanowires in an Aquatic Environment: Importance of Surface Charges

With increasing utilization of silver nanomaterials, growing concerns are raised on their deleterious effects to the environment. Once discharged in an aquatic environment, the interactions between silver nanowires (AgNWs) and proteins may significantly affect the environmental behaviors, fate, and toxicities of AgNWs. In the present study, three representative model proteins, including ovalbumin (OVA), bovine serum albumin (BSA), and lysozyme (LYZ), were applied to investigate the impacts of the interactions between proteins and AgNWs on the transformations (oxidative dissolution and sulfidation) of AgNWs in an aquatic environment. Fluorescence spectroscopy and isothermal titration calorimetry analyses indicated that there was very weak interaction between OVA or BSA and AgNWs, but there was a strong interaction between the positively charged LYZ and the negatively charged AgNWs. The presence of LYZ not only reversed the surface charge of AgNWs but also resulted in the breakup of the nanowire structure and increased the reactive surface area. The positively charged surface of AgNWs in the presence of LYZ favored the access of sulfide ions. As a consequence, the kinetics of oxidative dissolution and sulfidation of AgNWs were not affected by OVA and BSA but were significantly facilitated by LYZ. The results shed light on the important roles of electrostatic interactions between AgNWs and proteins, which may have important implications for evaluating the fate and effects of silver nanomaterials in complicated environments.

Inflammation Increases Susceptibility of Human Small Airway Epithelial Cells to Pneumonic Nanotoxicity

Exposure to inhaled anthropogenic nanomaterials (NM) with dimension <100 nm has been implicated in numerous adverse respiratory outcomes. Although studies have identified key NM physiochemical determinants of pneumonic nanotoxicity, the complex interactive and cumulative effects of NM exposure, especially in individuals with preexisting inflammatory respiratory diseases, remain unclear. Herein, the susceptibility of primary human small airway epithelial cells (SAEC) exposed to a panel of reference NM, namely, CuO, ZnO, mild steel welding fume (MSWF), and nanofractions of copier center particles (Nano-CCP), is examined in normal and tumor necrosis factor alpha (TNF-α)-induced inflamed SAEC. Compared to normal SAEC, inflamed cells display an increased susceptibility to NM-induced cytotoxicity by 15-70% due to a higher basal level of intracellular reactive oxygen species (ROS). Among the NM screened, ZnO, CuO, and Nano-CCP are observed to trigger an overcompensatory response in normal SAEC, resulting in an increased tolerance against subsequent oxidative insults. However, the inflamed SAEC fails to adapt to the NM exposure due to an impaired nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated cytoprotective response. The findings reveal that susceptibility to pulmonary nanotoxicity is highly dependent on the interplay between NM properties and inflammation of the alveolar milieu.

Bioavailability and translocation of metal oxide nanoparticles in the soil-rice plant system

To determine the bioavailability and translocation of metal oxide nanoparticles (MONPs) in the soil-rice plant system, we examined the accumulation and micro-distribution of ZnO nanoparticles (NPs), CuO NPs and CeO₂ NPs (50, 100 and 500 mg/kg) in the paddy soil and rice plants under flooded condition for 30 days using single-step chemical extraction and diffusive gradients in thin films (DGT) technique combined with micro X-ray fluorescence spectroscopy (μ-XRF). The results show that various MONPs changed the soil properties, especially the redox potential was enhanced to -165.33 to -75.33 mV compared to the control. The extraction efficiency of Zn, Cu and Ce in the paddy soil from high to low was EDTA, DTPA, CaCl₂ and DGT. Moreover, exposure to 500 mg/kg CuO NPs and CeO₂ NPs induced the primary accumulation of Cu and Ce elements in rice roots as high as 235.48 mg Cu/kg and 164.84 mg Ce/kg, respectively, while the Zn concentration in shoots was up to 313.18 mg/kg under highest ZnO NPs with a 1.5 of translocation factor. The effect of MONPs on the plant growth was mainly related to the chemical species and solubility of MONPs. Micro-XRF analysis shows that Zn was mostly located in the root cortex while Cu was primarily accumulated in the root exodermis and few Ce distributed in the root. Pearson correlation coefficients indicate that only DTPA-extracted metals in soil were significantly and well correlated to the Zn, Cu and Ce accumulation in rice seedlings exposed to MONPs. This work is of great significance for evaluating the environmental risks of MONPs in soil and ensuring the safety of agricultural products.

Adding carbon-based materials on anaerobic digestion performance: A mini-review

The anaerobic digestion is the adopted to remediate the pollutant and extract the bioenergy from the waste during the treatment. Effects of adding carbon-based materials on enhancement of digestion performance are studied in literature. This paper provided a mini review on the current research efforts on the traditional view on the cytotoxicity of carbon-based materials to the aquatic microorganisms and the novel "adding carbon-based material strategy" for improving the anaerobic digestion performances. The further research needs for comprehending the interactions between the added carbon materials, the substrates and the microorganisms and the impacts of adopting these additives on full-scale operations were highlighted.

Interaction of Ag+ with soil organic matter: Elucidating the formation of silver nanoparticles

Naturally silver nanoparticles (AgNPs) have been widely observed in ore deposits, coal, natural water and soil environment. Identifying the source of these naturally AgNPs could be helpful for the elucidation of the geochemical cycle of Ag⁺ and AgNPs. This paper presents the formation of AgNPs by reducing Ag⁺ in the presence of soil organic matter (SOM) under various environmentally relevant conditions. The formation of AgNPs associated with various SOM (peat humic acid (PHA), peat fulvic acid (PFA), and commercial humic acids (HA-1 and HA-2)) was determined and compared. The physicochemical properties of the tested SOM were studied by electron paramagnetic resonance (EPR) and attenuated total reflection-infrared (ATR-FTIR) techniques. The formation of AgNPs depended on reductive reactions mediated by SOM. Other influential parameters that influenced the formation of AgNPs included concentrations of Ag⁺ and SOM and the reaction temperature on AgNPs. The produced AgNPs were characterized by transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The mean hydrodynamic diameters of AgNPs associated with PHA and PFA were in range from 2.5 to 15 nm, which were smaller than that produced from HA-1 and HA-2 in the range from 20 to 120 nm. Two different Ag states, i.e., Ag₂O and Ag⁰ species, were observed by XPS technique. The results indicated that the formation of AgNPs depends largely on the types and the properties of natural organic matter. These findings have important implications for the fate of AgNPs under the soil environment.

PL Tunable GaN Nanoparticles Synthesis through Femtosecond Pulsed Laser Ablation in Different Environments

The tunable photoluminescence (PL) property is very important for gallium nitride (GaN) nanoparticles in the application of ultraviolet and blue optoelectronic devices, while conventional methods are not so satisfactory that alternative methods for preparing GaN nanoparticles should be studied. In this paper, ultra-small and well dispersed GaN nanoparticles are fabricated through femtosecond pulse laser ablation in air, water and ethanol. For the PL spectra of GaN nanoparticles, there are no shifts in air, red shifts in water and blue shifts in ethanol compared with the intrinsic PL spectra of bulk GaN. The X-ray photoelectron spectroscopy (XPS) results demonstrate that the various PL spectra can be due to the different components inside the GaN nanoparticles, which not only have effect on the PL emissions, but also greatly influence the intensity of PL. This study validates that the ablation environment has a great adjustable effect on the properties of GaN nanoparticles.

A global environmental health perspective and optimisation of stress

The phrase "what doesn't kill us makes us stronger" suggests the possibility that living systems have evolved a spectrum of adaptive mechanisms resulting in a biological stress response strategy that enhances resilience in a targeted quantifiable manner for amplitude and duration. If so, what are its evolutionary foundations and impact on biological diversity? Substantial research demonstrates that numerous agents enhance biological performance and resilience at low doses in a manner described by the hormetic dose response, being inhibitory and/or harmful at higher doses. This Review assesses how environmental changes impact the spectrum and intensity of biological stresses, how they affect health, and how such knowledge may improve strategies in confronting global environmental change.

Impact of consumer-resource dynamics on C. elegans-E. coli system exposed to nano zero-valent iron (nZVI)

Nano zero-valent iron (nZVI) is one of the most paramount nanoparticles (NPs) applied in environmental remediation, leading to great concerns for the potential impacts on soil ecosystem health. The objective of this study was to link toxicokinetics and consumer-resource dynamics in the Caenorhabditis elegans-Escherichia coli (worm-bacteria) ecosystem. The biokinetic parameters of bacteria and worms were obtained from toxicokinetic experiments and related published literature. Biomass dynamics of bacteria and worms were estimated by employing the modified Lotka-Volterra model. Dynamics of bacteria and worm biomass, internal concentrations of nZVI, bioconcentration factors (BCFs), and biomagnification factors (BMFs) were simulated based on the consumer-resource dynamics. Results showed that the biomass of worms steadily increased from 22.25 to 291.49 g L^-1, whereas the biomass of bacteria decreased from 17.17 to 4.70 × 10^-8 g L^-1 after 96-h exposures of nZVI. We also observed ratios of nZVI concentrations in worms and bacteria increased from 0.06 to 26.60 after 96 h. Moreover, decrements of the bioconcentration factor of E. coli (BCF_E) values from 0.82 to 0.03 after 96 h were observed, whereas values of BMFs increased from 0.06 to 57.62 after 96 h. Internal concentrations of nZVI in worms were found to be mainly influenced by the ingestion rate of bacteria by worms, and the biomass conversion of bacteria had the lowest effect. Implementation of the integrated bioaccumulation-consumer-resource model supports the hypothesis that the C. elegans-E. coli dynamics of internal nZVI concentrations could be effectively associated with the predator-prey behavior and was dominated by the same physiological parameter in the two biological systems.

Soybeans Grown with Carbonaceous Nanomaterials Maintain Nitrogen Stoichiometry by Assimilating Soil Nitrogen to Offset Impaired Dinitrogen Fixation

Engineered nanomaterials (ENMs) can enter agroecosystems because of their widespread use and disposal. Within soil, ENMs may affect legumes and their dinitrogen (N2) fixation, which are critical for food supply and N-cycling. Prior research focusing on end point treatment effects has reported that N2-fixing symbioses in an important food legume, soybean, can be impaired by ENMs. Yet, it remains unknown how ENMs can influence the actual amounts of N2 fixed and what plant total N contents are since plants can also acquire N from the soil. We determined the effects of one already widespread and two rapidly expanding carbonaceous nanomaterials (CNMs: carbon black, multiwalled carbon nanotubes, and graphene; each at three concentrations) on the N economy of soil-grown soybeans. Unlike previous studies, this research focused on processes and interactions within a plant-soil-microbial system. We found that total plant N accumulation was unaffected by CNMs. However, as shown by 15N isotope analyses, CNMs significantly diminished soybean N2 fixation (by 31-78%). Plants maintained N stoichiometry by assimilating compensatory N from the soil, accompanied by increased net soil N mineralization. Our findings suggest that CNMs could undermine the role of legume N2 fixation in supplying N to agroecosystems. Maintaining productivity in leguminous agriculture experiencing such effects would require more fossil-fuel-intensive N fertilizer and increase associated economic and environmental costs. This work highlights the value of a process-based analysis of a plant-soil-microbial system for assessing how ENMs in soil can affect legume N2 fixation and N-cycling.

Multifunctional inorganic nanomaterials for energy applications

Our society has been facing more and more serious challenges towards achieving highly efficient utilization of energy. In the field of energy applications, multifunctional nanomaterials have been attracting increasing attention. Various energy applications, such as energy generation, conversion, storage, saving and transmission, are strongly dependent upon the electrical, thermal, mechanical, optical and catalytic functions of materials. In the nanoscale range, thermoelectric, piezoelectric, triboelectric, photovoltaic, catalytic and electrochromic materials have made major contributions to various energy applications. Inorganic nanomaterials' unique properties, such as excellent electrical and thermal conductivity, large surface area and chemical stability, make them highly competitive in energy applications. In this review, the latest research and development of multifunctional inorganic nanomaterials in energy applications were summarized from the perspective of different energy applications. Furthermore, we also illustrated the unique functions of inorganic nanomaterials to improve their performances and the combination of the functions of nanomaterials into a device. However, challenges may be traced back to the limitations set by scaling the relations between multifunctional inorganic nanomaterials and energy devices.

Multiple hazardous elements in nanoparticulate matter from a Caribbean industrialized atmosphere

Modern microscopy studies are capable of revealing ultra-fine particles (UFPs) and nanoparticles (NPs) that are produced in the processes related to traffic vehicular, industrial, metropolitan, and marine aerosol dry deposition in the coastal zones. Especially, secondary aerosol passages complexes categories of NPs and UFPs, which can be accumulated on construction compounds and by dry deposition, encourages multiples monuments deterioration routes. The advanced electron microscopies method is one of the most utilized in environmental studies. Between the different industrial areas in the world, the Caribbean area is the most relevant symbols of air quality due to climatic conditions with strong winds, but this study shows that regionally the most industrialized region does not have an adequate air quality. In the present work, electron microscopy analyses are used to describe of the extent of ultra-fine particle and nanoparticles in walls in contact to weathering. Numerous phases were recognized by advanced mineralogy methods. Thanks to the new analytical procedure it was feasible to understand NPs and UFPs; the occurrence of potential hazardous elements (PHEs), most of them as minerals but also combined in multiple accumulations with Al-Cr-Fe-K-Mg-Pb-Si-Ti-Zn amorphous; and carbonaceous phases.