The objective of this work was to study the influence of annealing temperature on the structural changes and magnetic properties of the Ni
0.5
Zn
0.5
Fe
2
O
4
spinel-type nanoparticles. The ...nanomaterial was prepared by the chemical co-precipitation method and studied by thermal analysis (TG–DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), magnetic measurements and
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Fe Mössbauer spectrometry. XRD has revealed that the as-prepared sample shows poor crystallization with less defined diffraction lines. As the annealing temperature increases, the diffraction peaks become intense and well defined, reflecting perfect crystallization of the sample. The estimated crystallite size varies from 25 to 83 nm. TEM observations give information on the morphology and confirm the XRD results. To quantify the proportions of the iron atoms in the tetrahedral and octahedral sites, in-field Mössbauer spectrometry measurements were carried out at low temperature. Saturation magnetization (
M
s
) and the average hyperfine magnetic field
B
hf
increase gradually with annealing temperature. For the sample annealed at 1000 °C, the magnetic entropy change
Δ
S
M
max
and relative cooling power, measured under field change of 2T, are 0.67 J kg
−1
K
−1
and 112.5 J kg
−1
, respectively.
The Iberian wolf (Canis lupus signatus) is a top predator that inhabits the Iberian Peninsula. In Portugal, its numbers and distribution declined throughout the 20th century, due to human ...persecution, habitat degradation and prey decline, which have led to higher predation rates of livestock in the remaining packs. In Montesinho Natural Park (northeast Portugal), wild ungulate populations have been increasing in the last years, which may have led wolf to predate upon them. In order to assess Iberian wolf diet in this area, 85 wolf scats were collected from transects distributed throughout the study area in two periods between November 2017 and August 2019. Scat analysis indicated a high predation on wild ungulates, where the frequency of occurrence showed that roe deer was the most consumed prey (44%), followed by red deer (26%) and wild boar (24%). Domestic/wild cat (6%), domestic goat and stone marten (5%) were consumed in lower quantities. It was found a higher selection towards roe deer (D = 0.71) and this was the only prey item which was significantly dependent of the season of the year (χ2 = 16.95, df = 3, p < 0.001). This is the first study in Portugal where was recorded that wolves feed mainly on wild ungulates. We conclude that lower livestock predation may be correlated with higher wild ungulates densities in our study area, as well as suitable husbandry practices, leading to a shift on Iberian wolf diet from mainly livestock on previous studies to wild ungulates.
Infant formulae are the only possible alternative to breastfeeding during the first year of life, so it is crucial to assure their innocuousness. Infant formula undergoes heat treatments to ensure ...safety and shelf life. However, such processes impact health as they lead to the formation of malondialdehyde, acrolein, and α-dicarbonyl compounds, related to Maillard reaction. Thus, there is a need for improved analytical methods to ensure the safety, quality, and nutritional value of infant formulae, and also exploring the potential of specific compounds as indicators for quality control and monitoring purposes.
We developed and validated a novel, efficient, and cost-effective method using gas-diffusion microextraction for the simultaneous quantification of carbonyl compounds in infant formula. Malondialdehyde, acrolein, glyoxal, methylglyoxal, and diacetyl were detected as o-phenylenediamine derivatives using HPLC with UV detection. Parameters influencing extraction efficiency were studied using an asymmetric screening design. The validated method has shown excellent linearity, sensitivity, accuracy, and precision. It was applied to analyze 26 infant formula samples, including starter, follow-up, and special formulated powdered infant formula. Methylglyoxal was found in all samples (0.201–3.153 μg mL−1), while malondialdehyde was present only in certain starter formulas (1.033–1.802 μg mL−1). Acrolein (0.510–3.246 μg mL−1), glyoxal (0.109–1.253 μg mL−1), and diacetyl (0.119–2.001 μg mL−1) were detected in various sample types. Principal components and hierarchical cluster analyses have showcased distinct sample clustering based on analyte contents.
This study presents a novel methodology for the analysis of markers of thermal treatment and oxidative stability in infant formula. It contributes to the characterization of the products’ composition and quality control of infant formulae, thereby enhancing their safety and nutritional adequacy. This study also presents the first reported quantification of acrolein in infant formula and introduces the application of the acrolein-o-phenylenediamine derivative for food analysis.
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•Cost-effective and simultaneous determination of ACRL, MDA, GO, MGO, and DA by GDME and HPLC-UV.•First-time quantification of acrolein in infant formula using HPLC-UV.•Innovative ACRL-oPDA derivative used in food analysis. Promising in future research.•PCA and HCA reveal marked variations among infant formulae based on analyte content.•MDA, ACRL, and α-dicarbonyls as potential quality control markers in infant formula.
Gradient porous materials, particularly carbon-based materials, hold immense potential in the fields of batteries, energy storage, electrocatalysis, and sensing, among others, by synergistically ...combining the attributes associated with each pore size within a unified structural framework. In this study, we developed a gradient porous aramid (GP-Aramid) by incorporating cellulose acetate as a porosity promoter in the polymer casting solution in different proportions. These GP-Aramids were subsequently transformed into their pyrolyzed counterparts (GP-Pyramids), retaining their original structures while displaying diverse cellular or dense microstructures inherited from the parent aramid, as confirmed via scanning electron microscopy. X-ray diffraction spectra provided evidence of the conversion of aramids into carbonaceous materials. The materials showed structural defects observed through the intensity ratio of the G and D bands (ID/IG = 1.05) in the Raman spectra, while X-ray photoelectron spectra (XPS) revealed that the carbonization process yielded pyrolyzed carbon materials unusually rich in nitrogen (6%), oxygen (20%), and carbon (72%), which is especially relevant for catalysis applications. The pyrolyzed materials showed bulk resistivities from 5.3 ± 0.3 to 34.2 ± 0.6 depending on the meta- or para-orientation of the aramid and the porous structure. This work contributes to understanding these gradient porous aromatic polyamides’ broader significance and potential applications in various fields.
One emerging problem that recently has become a vastly acknowledged topic of concern is the environmental contamination by pharmaceuticals. Diclofenac (DCF) is one of the most common pharmaceuticals ...found, due to its high utilization and low removal rate in wastewater treatment processes. In this work, Solanum lycopersicum L. was used as a model to unravel how DCF contamination can affect crops, focusing on the internal mechanisms triggered by this exposure. For this purpose, plants were exposed to two different DCF concentrations (0.5 mg L−1 and 5 mg L−1). Results obtained here point towards a loss of shoot performance when plants were exposed to very high concentrations of DCF, but no delay or loss of yield in the flowering and fruit stages were ascribed to DCF contamination. Our data shows that a state of oxidative stress due to high reactive oxygen species accumulation was associated with this contamination, with very high DCF levels leading to a rise of lipid peroxidation, possibly accentuated by the inhibition of ROS-scavenging enzymes and unable to be counteracted by the visible upregulation of proline and the thiol-based redox network. Overall, these results allow to infer that in the current environmental context, no noticeable negative effects should be associated with the presence of DCF in soils where this crop is cultivated. However, the oxidative stress and lower biomass associated with the highest concentration are alarming, since DCF levels in the environment are continuously increasing and further measures are necessary to assess this problematic.
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•Water and soil contamination with pharmaceuticals is a threat to the environment.•Solanum lycopersicum L. exposed to diclofenac showed reduced shoot biomass.•The redox homeostasis of the plants was altered following diclofenac exposure.•DCF inhibited the performance of the enzymatic antioxidant system.•Proline and thiols were the main defense mechanisms activated by tomato plants.
Although it is well-known that nitroaromatic compounds quench the fluorescence of different conjugated polymers and form colored Meisenheimer complexes with proper nucleophiles, the potential of ...paper as a substrate for those macromolecules can be further developed. This work undertakes this task, impregnating paper strips with a fluorene-phenylene copolymer with quaternary ammonium groups, a bisfluorene-based cationic polyelectrolyte, and poly(2-(dimethylamino)ethyl methacrylate) (polyDMAEMA). Cationic groups make the aforementioned polyfluorenes attachable to paper, whose surface possesses a slightly negative charge and avoid interference from cationic quenchers. While conjugated polymers had their fluorescence quenched with nitroaromatic vapors in a non-selective way, polyDMAEMA-coated papers had a visual response that was selective to 2,4,6-trinitrotoluene (TNT), and that could be easily identified, and even quantified, under natural light. Far from implying that polyfluorenes should be ruled out, it must be taken into account that TNT-filled mines emit vapors from 2,4-dinitrotoluene (DNT) and dinitrobenzene isomers, which are more volatile than TNT itself. Atmospheres with only 790 ppbv TNT or 277 ppbv DNT were enough to trigger a distinguishable response, although the requirement for certain exposure times is an important limitation.
The interaction between sodium salicylate (NaSal) and the two macrocycles 5,11,17,23-tetrakissulfonatomethylene-2,8,14,20-tetra(ethyl)resorcinarene (Na
EtRA) and β-cyclodextrin (β-CD) has been ...studied by the determination of ternary mutual diffusion coefficients, and spectroscopic and computational techniques. The results obtained by the Job method suggest that the complex formation is given in a 1:1 ratio for all systems. The mutual diffusion coefficients and the computational experiments have shown that the β-CD-NaSal system presents an inclusion process, whereas the Na
EtRA-NaSal system forms an outer-side complex. This fact is also in line with the results obtained from the computational experiments, where the calculated solvation free energy has been found to be more negative for the Na
EtRA-NaSal complex because of the partial entry of the drug inside the Na
EtRA cavity.
Lupins and other legumes have been considered as alternative plant-based protein sources to soybeans for both humans and livestock. Furthermore, they can contribute to more sustainable agricultural ...systems. The productivity and chemical composition of legumes is highly variable between species, cultivars, and with the edaphoclimatic conditions.
This work evaluated the adaptability of seven
cultivars in two different sowing locations, during two consecutive years, through the characterization of their seed, as a means of investigating their suitability to be used as a source of food and/or feed.
cv. Tango and
cv. Acos were the most stable genotypes across the environments when considering the seed and protein production, while
cv. Alburquerque and
cv. Mister showed less variation in the total alkaloid content across the environments. The edaphoclimatic conditions affected seed and protein yields, as higher rainfall resulted in high productivity. The lower temperatures observed in the first year at both locations caused a reduction in the production of alkaloids in
cv. Acos and Cardiga. Due to the high alkaloid content of some of the studied cultivars their use as food or feed can pose some safety concerns. However, these cultivars can have high levels of resistance to herbivore and insect attacks, which can be of the utmost importance for the use of these crops for recovering poor or exhausted soils.
Ionizing radiation transport mechanisms in presence of magnetic fields can be described in terms of formalisms based on the Boltzmann radiation transport equation. However, when the transport occurs ...not in vacuum but in scattering media the difficulty of its analytical calculation considerably increases because of the random character of the radiation interaction processes with the scattering medium. In this context, the present work proposes and describe a methodology to characterize effects due to strong magnetic fields on electron trajectories by means of numerical techniques, such as Monte Carlo simulation, to be applied to scattering media, typically present in MRI-LINAC devices in radiotherapy situations. The obtained results for air as the scattering material show that variations of the electrons’ trajectories depend jointly on the magnetic field and the interactions with the scattering medium. Increasing the magnetic field intensity enhances the curvature of the trajectories while decreasing the displacement in the radial direction.
In this work, our main focus is to study the effect of oxygen vacancy on structural, magnetic, and optical properties of La0.8□0.2MnO3-δ (δ = 0, 0.1 and 0.2) manganites. The refinement of X-ray ...diffraction patterns shows that the samples with δ = 0 and 0.1 crystallize in the rhombohedral phase with R3¯c space group. Also, for δ = 0.2 the refinement has revealed the coexistence of R3¯c rhombohedral and Pnmaorthorhombic phases. The magnetic measurements M (T) shows that our samples have a transition from the ferromagnetic (FM) state to the paramagnetic (PM) state by increasing the temperature. The increase of oxygen deficiency rate causes a spin-glass-like state at low temperature with the presence of Griffiths phase above Curie temperature. Moreover, the hysteresis loop analysis shows an increase in the remanent magnetization and the coercive field when the creation of oxygen deficiency. Also, we find an agreement between experimental results and a theoretical study using ab initio density functional theory (DFT) based on correct Spin polarized Generalized Gradient Approximation SGGA + U. The results of the optical properties calculation revealed that our compounds could produce high absorption in the ultraviolet range.
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•The structural, magnetic and optical properties of La0.8□0.2MnO3-δ manganites have been studied by experimental and DFT calculation.•XRD refinement proved that Oxygen deficiency leads to a conversion in the structural phase.•The increases of oxygen vacancy rate leads to the appearance of the Griffiths phase in La0.8□0.2MnO2.8 sample.•The Investigated materials present a half-metallic ferromagnetism behavior.•The studied materials can be classed as promising candidates in spintronic and optoelectronic devices.
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