Search Results (91)

This study describes a quite special and interesting atmospheric event characterized by the simultaneous presence of fresh and aged smoke layers. These peculiar conditions occurred on 16 July 2024 at the CNR-IMAA atmospheric observatory (CIAO) in Potenza (Italy), and represent an ideal case for the evaluation of the impact of aging and transport mechanisms on both the optical and microphysical properties of biomass burning aerosol. The fresh smoke was originated by a local wildfire about 2 km from the measurement site and observed about one hour after its ignition. The other smoke layer was due to a wide wildfire occurring in Canada that, according to backward trajectory analysis, traveled for about 5–6 days before reaching the observatory. Synergetic use of lidar, ceilometer, radar, and microwave radiometer measurements revealed that particles from the local wildfire, located at about 3 km a.s.l., acted as condensation nuclei for cloud formation as a result of high humidity concentrations at this altitude range. Optical characterization of the fresh smoke layer based on Raman lidar measurements provided lidar ratio (LR) values of 46 ± 4 sr and 34 ± 3 sr, at 355 and 532 nm, respectively. The particle linear depolarization ratio (PLDR) at 532 nm was 0.067 ± 0.002, while backscatter-related Ångström exponent (AEβ) values were 1.21 ± 0.03, 1.23 ± 0.03, and 1.22 ± 0.04 in the spectral ranges of 355–532 nm, 355–1064 nm and 532–1064 nm, respectively. Microphysical inversion caused by these intensive optical parameters indicates a low contribution of black carbon (BC) and, despite their small size, particles remained outside the ultrafine range. Moreover, a combined use of CIAO remote sensing and in situ instrumentation shows that the particle properties are affected by humidity variations, thus suggesting a marked particle hygroscopic behavior. In contrast, the smoke plume from the Canadian wildfire traveled at altitudes between 6 and 8 km a.s.l., remaining unaffected by local humidity. Absorption in this case was higher, and, as observed in other aged wildfires, the LR at 532 nm was larger than that at 355 nm. Specifically, the LR at 355 nm was 55 ± 2 sr, while at 532 nm it was 82 ± 3 sr. The AEβ values were 1.77 ± 0.13 and 1.41 ± 0.07 at 355–532 nm and 532–1064 nm, respectively and the PLDR at 532 nm was 0.040 ± 0.003. Microphysical analysis suggests the presence of larger, yet much more absorbent particles. This analysis indicates that both optical and microphysical properties of smoke can vary significantly depending on its origin, persistence, and transport in the atmosphere. These factors that must be carefully incorporated into future climate models, especially considering the frequent occurrences of fire events worldwide. Full article

Alzheimer’s disease (AD) is one of the primary causes of disability and dependency among aging populations worldwide. Neuroinflammation may be a potential therapeutic target in AD. Moreover, ionizing radiation may be a tool for modulating neuroinflammation. Here, we used three mouse lines—C57Bl/6 and the transgenic AD models 5xFAD and Tau P301S—to investigate the effects of combined ionizing radiation (γ-rays and carbon-12 nuclei) on emotional state, cognitive abilities, and markers of microglial activation. The obtained data show that combined irradiation results in enhanced exploratory behavior and spatial learning in the C57Bl/6 mice. The same changes, as well as a decrease in anxiety, were found in the Tau P301S mice. Irradiation of the 5xFAD mice resulted in improved welfare and ability to discriminate odors. At the same time, irradiation led to an increase in the level of pro- and anti-inflammatory cytokines in the prefrontal cortex and, to a lesser extent, in the hippocampus of the C57Bl/6 and Tau P301S mice. An increase in macrophage inflammatory protein-1α in the prefrontal cortex and a decrease in interleukin 2β in the hippocampus were found in the 5xFAD mice. Taken together, our data indicate that ionizing radiation exposure is an adequate tool to modulate microglial activity in the brain and may provide cognitive and non-cognitive behavioral benefits in neurodegenerative disease conditions. Full article

The chemical composition and molecular structure of the pitch-like products obtained by liquid-phase reaction of bituminous coal with heavy hydrocarbon fractions of coal and petroleum origin as solvents at a moderate temperature were comprehensively characterized in terms of a new aromatic feedstock for needle coke and other valuable high-tech carbon materials. The molecular parameters of the products were characterized by using FTIR, ¹H NMR, ¹³C NMR and XPS. Liquid-phase chromatography was used to analyze benzo(a)pyrene (BaP) as a carcinogenicity marker. The chemical composition and the characteristics of the molecular structure of the products were shown to depend greatly on the solvent used. The product obtained using coal tar as a solvent was highly aromatic, its polyaromatic nuclei consisted predominantly of protonated and pericondensed cycles sparsely substituted by CH₃ and occasionally CH₂ groups. The product obtained using petroleum-derived heavy gas oil as solvent was much less aromatic and prone to autogenous surface oxidation. Its aromatic nuclei contained mainly protonated and highly alkylated catacondensed chains. The intermediate structural parameters were characteristic of the product obtained using binary solvent. A remarkable feature of the pitch-like products obtained was a reduced BaP concentration (up to 40 times compared to typical coal-tar pitch). In terms of the molecular structure, the pitch-like products obtained by low-temperature dissolution of coal can serve as a new polyaromatic feedstock with a reduced carcinogenicity for the production of valuable high-tech carbon materials, needle coke, in particular. Full article

To reduce solid waste production and enable the synergistic conversion of solid waste into high-value-added products, we introduce a novel, sustainable, and ecofriendly method. We fabricate nanofiber and nanosheet silicon carbides (SiC) through a carbothermal reduction process. Here, the calcined coal gangue, converted from coal gangue, serves as the silicon source. The carbon sources are the carbonized waste tire residue from waste tires and the pre-treated kerosene co-refining residue. The difference in carbon source results in the alteration of the morphology of the SiC obtained. By optimizing the reaction temperature, time, and mass ratio, the purity of the as-made SiC products with nanofiber-like and nanosheet-like shapes can reach 98%. Based on the influence of synthetic conditions and the results calculated from the change in the Gibbs free energy of the reactions, two mechanisms for SiC formation are proposed, namely the reaction of intermediate SiO with CO to form SiC-nuclei-driven nanofibrous SiC and the SiO-deposited carbon surface to fabricate nuclei-induced polymorphic SiC (dominant nanosheets). This work provides a constructive strategy for preparing nanostructured SiC, thereby achieving “turning trash into treasure” and broadening the sustainable utilization and development of solid wastes. Full article

Purpose: The purpose of this study is to analyze the relationship between nuclear charge (Z), atomic mass (A), LET (linear energy transfer for maximal relative biological effectiveness (RBE)) for accelerated ions based on the hypothesis that for each ion, LET_U is related to their nuclear radius. Methods: Published LET_U data for proton, helium, carbon, neon, silicon, argon, and iron ions and their Z and A numbers are fitted by a power law function (PLF) and compared with PLF based on atomic cross-sections and nuclear dimensions for spherical or spheroidal atomic nuclei. The PLF allows for isoeffective RBE estimations for different ions at any value of LET based on the LET_U estimations. For any two ions, A and B, and a specified bioeffect obtained at LET_A, the equivalent isoeffective LET_B, is estimated using ${LET}_B={LET}_A.\left({\displaystyle \frac{{LET}_{U\left[B\right]}}{{LET}_{U\left[A\right]}}}\right)$. Results: The data-fitting program provided the following results: ${LET}_U=78.1.A^{0.26}$, and ${LET}_U=86.6.Z^{0.29}$, where 78.1 and 86.6 keV.μm⁻¹ are the proton LET_U values (i.e., without proton cellular range limit considerations). Goodness-of-fit tests are similar for each model, but the proton estimations differ. These exponents are lower than 0.66 and 0.33 (those for nuclear cross-sections and spherical nuclear radii, respectively), but suggest prolate nuclear shapes in most of the ions studied. Worked examples of estimating isoeffective LET values for two different ions are provided. Conclusions: The fitted power law relationships between LET_U and Z or A are broadly equivalent and compatible with prolate nuclear shapes. These models may offer a more rational basis for future ion-beam radiobiology research. Full article

In this study, CO₂ reacted with a curing agent through nucleophilic addition to form ammonium salts, enabling the stable capture and internal release of CO₂, which achieved gas-phase nucleation and foaming. Additionally, the introduction of wave-absorbing agents improved the absorption mechanism and promoted uniform foaming. This nucleation-free foaming process relies on the induced growth of gas nuclei and the synergistic effect of the wave-absorbing agents, effectively preventing the uneven foaming issues caused by traditional nucleating agents. Ultimately, a lightweight epoxy foam absorbing material (LFAM) was developed. BET tests showed that 2.0 wt% carbon-based wave-absorbing agents (LFAMs–A2) expanded the material’s volume to 4.6 times its original size, forming a uniform porous structure. VNA tests revealed that LFAMs–A2 achieved a minimum reflection loss of −13.25 dB and an absorption bandwidth of 3.7 GHz in the 12–18 GHz range. The material with 2.0 wt% ferrite-based wave-absorbing agents (LFAMs–C2) achieved a minimum reflection loss of −26.83 dB at 16.6 GHz and an absorption bandwidth of 5.3 GHz, nearly covering the Ku band. DSC tests indicated that the material maintained good thermal stability at 150 °C. This study provides a new approach for lightweight coatings and structural optimization, with broad application potential in 5G communications, microwave anechoic chambers, and aerospace fields. Full article

In this study, we examine thermal conductivity and the thermal Hall effect in electron-ion plasmas relevant to hot neutron stars, white dwarfs, and binary neutron star mergers, focusing on densities found in the outer crusts of neutron stars and the interiors of white dwarfs. We consider plasma consisting of single species of ions, which could be either iron ${}^{56}\mathrm{Fe}$ or carbon ${}^{12}\mathrm{C}$ nuclei. The temperature range explored is from the melting temperature of the solid $T\sim {10}^9$ K up to ${10}^{11}$ K. This covers both degenerate and non-degenerate electron regimes. We find that thermal conductivity increases with density and temperature for which we provide analytical scaling relations valid in different regimes. The impact of magnetic fields on thermal conductivity is also analyzed, showing anisotropy in low-density regions and the presence of the thermal Hall effect characterized by the Righi–Leduc coefficient. The transition froma degenerate to non-degenerate regime is characterized by a minimum ratio of thermal conductivity to temperature, which is analogous to the minimum observed already in the case of electrical conductivity. We provide also formulas fit to our numerical results, which can be used in dissipative magneto-hydrodynamics simulations of warm compact stars. Full article

This investigation examines the dynamic behavior of the nodular graphite structure in ductile cast iron at elevated temperatures during the recycling process. It comprises a systematic analysis of the impact of high temperature on the change in chemical composition, followed by a set of examinations of the nodular graphite structure dissolution mechanism at the early phase of the remelting process. The results indicate that prolonged holding at higher temperatures affects the carbon or silicon concentration due to oxidation, which correlates with the operating temperature and the dynamic concentration proportion of those two main alloying elements. It is also substantiated that the dissolution of nodular graphite, the only carbon source during the ductile cast iron remelting process, does not occur primarily in the liquid state but has already started during the solid phase because of austenitization. This dissolution is governed mainly by a surface reaction, as indicated by the residual graphite structure with preserved nonmetallic nuclei. Hence, this approach also provides an alternative method for observing the nodular graphite core by intentionally partially dissolving the graphite structure. Full article

In orbital and ground-based experiments, it has been demonstrated that ionizing radiation (IR) can stimulate the locomotor and exploratory activity of rodents, but the underlying mechanism of this phenomenon remains undisclosed. Here, we studied the effect of combined IR (0.4 Gy γ-rays and 0.14 Gy carbon-12 nuclei) on the locomotor and exploratory activity of rats, and assessed the sensorimotor cortex volume by magnetic resonance imaging-based morphometry at 1 week and 7 months post-irradiation. The sensorimotor cortex tissues were processed to determine whether the behavioral and morphologic effects were associated with changes in neurotrophin content. The irradiated rats were characterized by increased locomotor and exploratory activity, as well as novelty-seeking behavior, at 3 days post-irradiation. At the same time, only unirradiated rats experienced a significant decrease in the sensorimotor cortex volume at 7 months. While there were no significant differences at 1 week, at 7 months, the irradiated rats were characterized by higher neurotrophin-3 and neurotrophin-4 content in the sensorimotor cortex. Thus, IR prevents the age-associated decrease in the sensorimotor cortex volume, which is associated with neurotrophic and neurogenic changes. Meanwhile, IR-induced increases in locomotor activity may be the cause of the observed changes. Full article

The effects of austenitizing and austempering temperatures on the bainite transformation kinetics and the microstructural and mechanical properties of a medium-carbon high-silicon ultra-fine bainitic steel were investigated via dilatometric measurements, microstructural characterization and mechanical tests. It is demonstrated that the optimum austenitizing temperature exists for 0.3 wt.%C ultra-fine bainitic steel. Although the finer austenite grain at 950 °C provides more bainite nuclei site and form finer bainitic ferrite plates, the lower dislocation density in plates and the higher volume fraction of the retained austenite reduces the strength and impact toughness of ultra-fine steel. When the austenitizing temperature exceeds 1000 °C, the true thickness of bainitic ferrite plates and the volume fraction of blocky retained austenite in the bainite microstructure increase significantly with the increases in austenitizing temperature, which do harm to the plasticity and impact toughness. The effect of austempering temperature on the transformation behavior and microstructural morphology of ultra-fine bainite is greater than that of austenitizing temperature. The prior martensite, formed when the austempering temperature below Ms, can refine the bainitic ferrite plates and improve the strength and impact toughness. However, the presence of prior martensite divides the untransformed austenite and inhibits the growth of bainite sheaves, thus prolonging the finishing time of bainite transformation. In addition, prior martensite also strengthens the stability of untransformed austenite though carbon partition and enhances the volume fraction of blocky retained austenite, which reduces the plasticity of ultra-fine bainitic steel. According to the experimental results, the optimum austempering process for 0.3 wt. %C ultra-fine bainitic steel is through austenitization at 1000 °C and austempering at 340 °C. Full article

The process of metal dissolution under a delaminated insulating polymer coating (underfilm dissolution) has been studied. For this purpose, we used an experimental setup that simulates the process of corrosion of underground metal structures in the presence of through defects in the polymer coating and/or extended areas of peeling of the polymer coating from the metal (loss of adhesion)—subfilm cavities partially or completely filled with electrolyte. In particular, the distribution of the protective current under a peeled polymer coating was studied, and a sharp decrease in the value of the protective current was shown at a distance of 1–3 cm from the edge of the defect with a gap between the metal and the coating of 1–6 mm. The localized nature of metal corrosion under the exfoliated polymeric coating has been demonstrated. The ratio of the areas with accelerated corrosion to the total area of the metal can be 1 to 100. It has been established that there are areas of anodic dissolution of the metal during cathodic polarization of the entire sample with a peeled coating. The activating effect of carbon dioxide and hydrogen sulfide on the corrosion and anodic dissolution of steel under the coating was shown. So, it has been established that the dissolution current flowing from the anodic sections on a surface can increase approximately 10 times in the presence of carbon dioxide and hydrogen sulfide. A synergistic effect of these compounds on the process of localized underfilm corrosion of steel was detected. It has been developed a mechanism for the formation of localized corrosion damage to steel under a delaminated polymeric coating, which can be the nuclei of corrosion cracks upon reaching a certain level of mechanical loads, i.e., stress corrosion cracking (SCC) of carbon steel. Possible manners of inhibiting underfilm dissolution of metals are considered, and a method for pre-treatment of the surface with solutions of organosilanes, which ensures the formation of surface self-assembled polymeric siloxane nanolayers responsible for inhibiting underfilm corrosion of steel, is proposed. Full article

There is a controversy involved in the models of the formation of serpulid tube microstructures, which either have been formed in similar ways to molluscan structures or in an alternative, unique serpulid way. A scanning electron microscope (SEM) study of the tube microstructure of Crucigera zygophora has been performed. A new serpulid tube microstructure, an aggregative SIOP, has been discovered in C. zygophora, herein termed ASIOP. During the first phase of crystallization, the sparsely located nuclei of the ASIOP structure formed, and in the second phase of crystal growth, the nucleation of spherultic sectors took place on the surface of preformed nuclei. The ASIOP structure differs from SIOP by more sparsely located crystallisation centres (nuclei) and the slower formation (i.e., crystallisation) of basic units. The formation of the ASIOP structure cannot be fully explained by the classical carbonate slurry model. Future comparative studies should show whether molluscan crossed spindle-like structures and serpulid SIOP structures are structural analogues. Full article

The effects of emissions of diesel engines on black carbon and particle number concentrations, as well as climate-relevant aerosol properties, are explored for a summertime period in the Eastern U.S. using the chemical transport model PMCAMx-UF. A 50% reduction in diesel particulate emissions results in lower (23%) black carbon mass concentrations, as expected, and similar changes both in magnitude (27–30%) and spatial pattern for the absorption coefficient. However, an average 2% increase in the total particle number concentrations is predicted due to a decrease in the coagulation and condensation sinks and, at the same time, a 2% decrease in N₁₀₀ (particles larger than 100 nm) concentrations. The diesel reduction results suggest that mitigation of large diesel particles and/or particle mass emissions can reduce climate-relevant properties related to the absorption of black carbon and provide health benefits; however, the changes could also have the unintended effect of increased ultrafine particle number concentrations. Changes in cloud condensation nuclei are predicted to be significantly less than expected, assuming a proportional reduction during this photochemically active period. Doubling the diesel emissions results in a domain-averaged 3% decrease in total particle number concentrations and a 3% increase in N₁₀₀ concentrations. PM_2.5 BC concentrations increase on average by 46%, and similar changes (52–60%) are predicted for the absorption coefficient. Extinction coefficients for both perturbation simulations changed by only a few percent due to the dominance of scattering aerosols in the Eastern U.S. during this period characterized by high photochemical activity. Full article

Glaucoma therapy aims at lowering intra-ocular pressure (IOP). Brinzolamide, a carbonic anhydrase inhibitor, is utilized as a second-line medication for treating ocular hypertension and primary open-angle glaucoma (POAG). The drug lowers the IOP making it a therapeutic agent against glaucoma, and due to its poor water solubility, is commercially available as Azopt^®, a 1% ophthalmic suspension. Adverse effects such as blurred vision, ocular irritation, discomfort, and bitter taste are associated with the use of the marketed brinzolamide formulation. This study aims to test the feasibility of formulating and in vitro testing of brinzolamide-PLGA nanoparticles for improved toxicity profile. The nanoparticles were prepared by the oil-in-water (O/W) emulsion-solvent evaporation method. Particle size and zeta potential were determined by dynamic light scattering (DLS). The morphology of the nanoparticles was determined by scanning electron microscopy (SEM). Encapsulation of the drug was verified by high-performance liquid chromatography (HPLC) and the compatibility of the polymer and drug was verified by Fourier transform infrared (FTIR) spectroscopy. The in vitro drug release profile was assessed employing the dialysis method. Intracellular localization of the nanoparticles was assessed by confocal microscopy utilizing Rhodamine 123-loaded nanoparticles. Cytotoxicity of the formulation was assessed on Statens Seruminstitut Rabbit Cornea (SIRC) and transfected Human Corneal Epithelial (SV40 HCEC) cell lines. The particle size of the nanoparticle formulations ranged from 202.3 ± 2.9 nm to 483.1 ± 27.9 nm for blank nanoparticles, and 129.6 ± 1.5 nm to 350.9 ± 8.5 nm for drug-loaded nanoparticles. The polydispersity of the formulations ranged from 0.071 ± 0.032 to 0.247 ± 0.043 for blank nanoparticles, and 0.089 ± 0.028 to 0.158 ± 0.004 for drug-loaded nanoparticles. Drug loading and encapsulation efficiencies ranged from 7.42–15.84% and 38.93–74.18%, respectively. The in vitro drug release profile for the optimized formulation was biphasic, with a ~54% burst release for the initial 3 h, followed by a cumulative 85% and 99% released at 24 and 65 h, respectively. Uptake study showed nanoparticles(NPs) localization in the cytoplasm and around the nuclei of the cells. Brinzolamide-PLGA nanoparticles were successfully developed, characterized, and tested in vitro. Preliminary data show intracellular localization of the nanoparticles in the cytoplasm of SIRC and SV40 HCEC cells. The formulations appeared to be relatively non-cytotoxic to the cells. The research data from the study provided preliminary data for successful development and promising in vitro absorption efficacy for brinzolamide-loaded PLGA nanoparticle formulation. Full article

Utilizing carbon quantum dots (CQDs) as biomaterials for delivering small substances has gained significant attention in recent research. However, the interactions and mechanisms of action of CQDs on plants have received relatively little focus. Herein, we investigated the transportation of CQDs into various organs of Arabidopsis thaliana (L.) Heynh. via the vessel system, leading to the epigenetic inheritance of Argonaute family genes. Our findings reveal that CQDs may interact with microRNAs (miRNAs), leading to the repression of post-transcriptional regulation of target genes in the cytoplasm. Transcriptome and quantitative PCR analyses demonstrated consistent gene expression levels in offspring. Moreover, microscopic observations illustrated rapid CQD localization on cell membranes and nuclei, with increased nuclear entry at higher concentrations. Notably, our study identified an alternative regulatory microRNA, microRNA172D, for the Argonaute family genes through methylation analysis, shedding light on the connection between CQDs and microRNAs. Full article