In this study, PM2.5 airborne particulate matter was collected over a full year at a costal site of the Central Mediterranean Sea and analysed for its chemical composition and oxidative potential ...(OP), determined by the dithiothreitol (DTT) and the ascorbic acid (AA) assays. In autumn-winter, the volume normalized oxidative OP (OPV) were 0.29 ± 0.03 nmol min−1 m−3 and 0.21 ± 0.03 nmol min−1 m−3 for the DTT (OPDTTV) and AA (OPAAV) assay, respectively. In spring-summer the OPDTTV values were higher than OPAAV responses, i.e., 0.19 ± 0.02 nmol min−1 m−3 vs. 0.09 ± 0.01 nmol min−1 m−3. Overall, marked seasonality was observed with higher values in Autumn-Winter (AW) than in Spring-Summer (SS), i.e., 1.5 and 2.3 times increase for OPDTTV and OPAAV, respectively.
In the cold season, the OPV activity was broadly correlated with metals and carbon species, such as K+, NO3−, Ba, Cd, Cu, Fe, Mn, P, V, OC, EC, Acetate, Oxalate and Glycolate (p < 0.05). This suggested the main contribution of a “mixed anthropogenic” source, consisting of the biomass burning (K+, OC and EC) and traffic (Ba, Cu, Fe, Mn, V, EC) emissions. In SS, OPV was significantly correlated with only few species i.e., OC, EC, Cu, and NO3−, suggesting main association with the “mixed anthropogenic” and the “reacted dust” sources.
For each sampling day, PM2.5 and PM10 samples were simultaneously collected and analysed to investigate the variation of the OP activity in relation with the particle size and chemical composition.
OPDTTV values exhibited a poor particle-size dependence, with similar values close to 0.20 ± 0.04 nmol min−1 m−3 in both fractions. This could be explained by the association of OPDTTV with species mainly accumulated in the fine fraction, i.e., OC, POC and EC and K+. Otherwise, the OPAAV responses exhibited a clear particle-size dependence, with significantly higher values for PM10 than for PM2.5, i.e., 0.35 ± 0.06 vs. 0.21 ± 0.03 nmol min−1 m−3 in AW and 0.23 ± 0.04 vs. 0.09 ± 0.01 in SS. This may be supported by the strong correlation of OPAAV with Cu and Fe, which were most abundant metals in the PM10 fraction.
The data of specific monitoring days were investigated in detail to better highlight the impact of some individual redox active species on the OPDTTV and OPAAV responses.
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•Oxidative potential was assessed for PM2.5 at a Central Mediterranean Site.•Oxidative potential and chemical composition of PM2.5 and PM10 were compared.•The dependence of the OPDTT and OPAA responses on seasons were investigated.•OPDTT were similar in PM2.5 and PM10 and highly associated with OC, EC and K+.•OPAA were higher in PM10 than in PM2.5 and highly associated with Cu and Fe.
The oxidative potential of PM2.5 and PM10 samples was assessed with Dithiothreitol and Ascorbic Acid assays: the variation of OP responses was related with the PM size and chemical composition.
Exoplanetary science is on the verge of an unprecedented revolution. The thousands of exoplanets discovered over the past decade have most recently been supplemented by discoveries of potentially ...habitable planets around nearby low-mass stars. Currently, the field is rapidly progressing toward detailed spectroscopic observations to characterize the atmospheres of these planets. Various surveys from space and the ground are expected to detect numerous more exoplanets orbiting nearby stars that make the planets conducive for atmospheric characterization. The current state of this frontier of exoplanetary atmospheres may be summarized as follows.
We have entered the era of comparative exoplanetology thanks to high-fidelity atmospheric observations now available for tens of exoplanets.
Recent studies reveal a rich diversity of chemical compositions and atmospheric processes hitherto unseen in the Solar System.
Elemental abundances of exoplanetary atmospheres place important constraints on exoplanetary formation and migration histories.
Upcoming observational facilities promise to revolutionize exoplanetary spectroscopy down to rocky exoplanets.
The detection of a biosignature in an exoplanetary atmosphere is conceivable over the next decade.
In the present review, we discuss the modern and future landscape of this frontier area of exoplanetary atmospheres. We start with a brief review of the area, emphasising the key insights gained from different observationalmethods and theoretical studies. This is followed by an in-depth discussion of the state of the art, challenges, and future prospects in three forefront branches of the area.
Advances in nanoscale self-assembly have enabled the formation of complex nanoscale architectures. However, the development of self-assembly strategies toward bottom-up nanofabrication is impeded by ...challenges in revealing these structures volumetrically at the single-component level and with elemental sensitivity. Leveraging advances in nano-focused hard x-rays, DNA-programmable nanoparticle assembly, and nanoscale inorganic templating, we demonstrate nondestructive three-dimensional imaging of complexly organized nanoparticles and multimaterial frameworks. In a three-dimensional lattice with a size of 2 micrometers, we determined the positions of about 10,000 individual nanoparticles with 7-nanometer resolution, and identified arrangements of assembly motifs and a resulting multimaterial framework with elemental sensitivity. The real-space reconstruction permits direct three-dimensional imaging of lattices, which reveals their imperfections and interfaces and also clarifies the relationship between lattices and assembly motifs.
Sweet potatoes are becoming a research focus in recent years due to their unique nutritional and functional properties. Bioactive carbohydrates, proteins, lipids, carotenoids, anthocyanins, ...conjugated phenolic acids, and minerals represent versatile nutrients in different parts (tubers, leaves, stems, and stalks) of sweet potato. The unique composition of sweet potato contributes to their various health benefits, such as antioxidative, hepatoprotective, antiinflammatory, antitumor, antidiabetic, antimicrobial, antiobesity, antiaging effects. Factors affecting the nutritional composition and bio-functions of sweet potato include the varieties, plant parts, extraction time and solvents, postharvest storage, and processing. The assays for bio-function evaluation also contribute to the variations among different studies. This review summarizes the current knowledge of the chemical composition of sweet potato, and their bio-functions studied in vitro and in vivo. Leaves, stems, and stalks of sweet potato remain much underutilized on commercial levels. Sweet potato can be further developed as a sustainable crop for diverse nutritionally enhanced and value-added food products to promote human health.
Composition and bio-function representatives of different parts of the sweet potato. Display omitted
•Chemical composition of various parts of the sweet potato are summarized.•Beneficial and detrimental effects of sweet potato on human health are reviewed.•Creating value from underutilized leaves, stalks, and stems.•In vitro and in vivo physiological functions should be correlated.
Abstract Ion Beam Analysis (IBA) utilizing MeV ion beams provides valuable insights into surface elemental composition across the entire periodic table. While ion beam measurements have advanced ...towards high throughput for mapping applications, data analysis has lagged behind due to the challenges posed by large volumes of data and multiple detectors providing diverse analytical information. Traditional physics-based fitting algorithms for these spectra can be time-consuming and prone to local minima traps, often taking days or weeks to complete. This study presents an approach employing a Mixture Density Network (MDN) to model the posterior distribution of Elemental Depth Profiles (EDP) from input spectra. Our MDN architecture includes an encoder module (EM), leveraging a Convolutional Neural Network-Gated Recurrent Unit (CNN-GRU), and a Mixture Density Head (MDH) employing a Multi-Layer Perceptron (MLP). Validation across three datasets with varying complexities demonstrates that for simple and intermediate cases, the MDN performs comparably to the conventional automatic fitting method (Autofit). However, for more complex datasets, Autofit still outperforms the MDN. Additionally, our integrated approach, combining MDN with the automatic fit method, significantly enhances accuracy while still reducing computational time, offering a promising avenue for improved analysis in IBA.
Carbon dioxide capture and mitigation form a key part of the technological response to combat climate change and reduce CO2 emissions. Solid materials capable of reversibly absorbing CO2 have been ...the focus of intense research for the past two decades, with promising stability and low energy costs to implement and operate compared to the more widely used liquid amines. In this review, we explore the fundamental aspects underpinning solid CO2 sorbents based on alkali and alkaline earth metal oxides operating at medium to high temperature: how their structure, chemical composition, and morphology impact their performance and long-term use. Various optimization strategies are outlined to improve upon the most promising materials, and we combine recent advances across disparate scientific disciplines, including materials discovery, synthesis, and in situ characterization, to present a coherent understanding of the mechanisms of CO2 absorption both at surfaces and within solid materials.
Beet and cane molasses are produced worldwide as a by-product of sugar extraction and are widely used in animal nutrition. Due to their composition, they are fed to ruminants as an energy source. ...However, molasses has not been properly characterized in the literature; its description has been limited to the type (sugarcane or beet) or to the amount of dry matter (DM), total or water-soluble sugars, crude protein, and ash. Our objective was to better characterize the composition of cane and beet molasses, examine possible differences, and obtain a proper definition of such feeds. For this purpose, 16 cane and 16 beet molasses samples were sourced worldwide and analyzed for chemical composition. The chemical analysis used in this trial characterized 97.4 and 98.3% of the compounds in the DM of cane and beet molasses, respectively. Cane molasses contained less DM compared with beet molasses (76.8 ± 1.02 vs. 78.3 ± 1.61%) as well as crude protein content (6.7 ± 1.8 vs. 13.5 ± 1.4% of DM), with a minimum value of 2.2% of DM in cane molasses and a maximum of 15.6% of DM in beet molasses. The amount of sucrose differed between beet and cane molasses (60.9 ± 4.4 vs. 48.8 ± 6.4% of DM), but variability was high even within cane molasses (39.2–67.3% of DM) and beet molasses. Glucose and fructose were detected in cane molasses (5.3 ± 2.7 and 8.1 ± 2.8% of DM, respectively), showing high variability. Organic acid composition differed as well. Lactic acid was more concentrated in cane molasses than in beet molasses (6.1 ± 2.8 vs. 4.5 ± 1.8% of DM), varying from 1.6 to 12.8% of DM in cane molasses. Dietary cation-anion difference showed numerical differences among cane and beet molasses (7 ± 53 vs. 66 ± 45 mEq/100 g of DM, on average). It varied from −76 to +155 mEq/100 g of DM in the cane group and from +0 to +162 mEq/100 g of DM in the beet group. Data obtained in this study detailed differences in composition between sources of molasses and suggested that a more complete characterization could improve the use of molasses in ration formulation.
The long-standing popularity of semiconductor photocatalysis due to its great potential in a variety of applications has resulted in the creation of numerous semiconductor photocatalysts, which ...stimulated the development of various characterization methods. This review aims to summarize the main characterization methods for assessing the most important properties of semiconductor photocatalysts, including their chemical composition (elemental composition, and chemical state/structure), physical properties (physical structure, crystallographic properties, optical absorption, charge dynamics, defects, and colloidal and thermal stability), and band structure (band gap, band edges/band edge offsets, and Fermi level). The discussion on each of these methods starts with a concise presentation of its fundamentals followed by carefully selected examples. At the end, a chart correlating the properties of a semiconductor with its potential characterization methods as well as outlook are provided. Overall, the aim of this review article is to help materials chemists and physicists, particularly students, in selecting suitable techniques for the characterization of semiconductor photocatalysts and potentially other relevant materials.
The long-standing popularity of semiconductor photocatalysts stimulated their characterization, which is the subject of this review aiming to help materials chemists and physicists, particularly students, to select suitable characterization methods.
•Slag is an engineering waste and by-product in the production of iron in a blast furnace.•AAS consists of alumina-silicates and silicates of lime; this makes it suitable for the production of ...geopolymers.•Slag is an excellent performance cementitious material, promoting to achieve higher compressive strength.•To examine the influences of GGBFS and AAS on the morphological characteristics of concrete.•To study the characteristic of high fineness GGBFS, to improve the microstructure property.
A single ton of ordinary Portland cement (OPC) demands around 4.0 G Joule energy and creates about a ton of CO2 emission. As part of our effort to preserve the environment, the incorporation of ground granulated blast-furnace slag (GGBFS) or fully replaced by alkali-activated slag (AAS) as an alternative binder to OPC. This concrete is environmental-friendly and also eases concerns in energy usage, raw material, and manufacturing cost for the traditional concrete. The cementitious properties of GGBFS and AAS promote their usage in the concrete matrix. Partial inclusion of slag for cement produces OPC or fully replaced by AAS is getting more attention as it is more pumpable, chemically stable, and resistant to an aggressive environment. This paper reviews the source, clean production and chemical compositions of the GGBFS and AAS. This literature review also objects to provide reviews on the properties, hardening conditions, and behaviors of GGBFS and AAS -based concrete composites as well as to synopsize the research development trends to generate comprehensive insights into the potential applications of GGBFS and AAS concrete as raw building materials for making sustainable and greener concrete composites, towards industrializing ecofriendly buildings today.
High-entropy alloys are a class of materials that contain five or more elements in near-equiatomic proportions
. Their unconventional compositions and chemical structures hold promise for achieving ...unprecedented combinations of mechanical properties
. Rational design of such alloys hinges on an understanding of the composition-structure-property relationships in a near-infinite compositional space
. Here we use atomic-resolution chemical mapping to reveal the element distribution of the widely studied face-centred cubic CrMnFeCoNi Cantor alloy
and of a new face-centred cubic alloy, CrFeCoNiPd. In the Cantor alloy, the distribution of the five constituent elements is relatively random and uniform. By contrast, in the CrFeCoNiPd alloy, in which the palladium atoms have a markedly different atomic size and electronegativity from the other elements, the homogeneity decreases considerably; all five elements tend to show greater aggregation, with a wavelength of incipient concentration waves
as small as 1 to 3 nanometres. The resulting nanoscale alternating tensile and compressive strain fields lead to considerable resistance to dislocation glide. In situ transmission electron microscopy during straining experiments reveals massive dislocation cross-slip from the early stage of plastic deformation, resulting in strong dislocation interactions between multiple slip systems. These deformation mechanisms in the CrFeCoNiPd alloy, which differ markedly from those in the Cantor alloy and other face-centred cubic high-entropy alloys, are promoted by pronounced fluctuations in composition and an increase in stacking-fault energy, leading to higher yield strength without compromising strain hardening and tensile ductility. Mapping atomic-scale element distributions opens opportunities for understanding chemical structures and thus providing a basis for tuning composition and atomic configurations to obtain outstanding mechanical properties.
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