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We study solutions for the Klein–Gordon equation with vector and scalar potentials of the Coulomb types under the influence of noninertial effects in the cosmic string spacetime. We also investigate a quantum particle described by the Klein–Gordon oscillator in the background spacetime generated by a cosmic string. An important result obtained is that the noninertial effects restrict the physical region of the spacetime where the particle can be placed. In addition, we show that these potentials can form bound states for the Klein–Gordon equation in this kind of background.

Age-related complications such as neurodegenerative disorders are increasing and remain cureless. The possibility of altering the progression or the development of these multifactorial diseases through diet is an emerging and attractive approach with increasing experimental support. We examined the potential of known bioavailable phenolic sulfates, arising from colonic metabolism of berries, to influence hallmarks of neurodegenerative processes. In silico predictions and in vitro transport studies across blood-brain barrier (BBB) endothelial cells, at circulating concentrations, provided evidence for differential transport, likely related to chemical structure. Moreover, endothelial metabolism of these phenolic sulfates produced a plethora of novel chemical entities with further potential bioactivies. Pre-conditioning with phenolic sulfates improved cellular responses to oxidative, excitotoxicity and inflammatory injuries and this attenuation of neuroinflammation was achieved via modulation of NF-κB pathway. Our results support the hypothesis that these small molecules, derived from dietary (poly)phenols may cross the BBB, reach brain cells, modulate microglia-mediated inflammation and exert neuroprotective effects, with potential for alleviation of neurodegenerative diseases.

In this paper, we investigate a generalization of Kiselev black holes by introducing a varying equation-of-state parameter for the anisotropic fluid surrounding the black hole. We extend this model by allowing w in the expression p t ( r ) / ρ ( r ) = ( 3 w + 1 ) / 2 to vary as a function of the radial coordinate, and derive new solutions to the Einstein field equations for this configuration. In particular, we study solutions that describe regular black holes. By choosing specific forms of w ( r ), we obtain regular black hole solutions, and show that the matter surrounding the black hole can satisfy the weak and strong energy conditions under certain values of parameters analyzed. Due to the generality of this treatment, other categories of black holes can be obtained with particular choices of the equation-of-state parameter. Our analysis confirms that the curvature invariants associated with the regular black holes remain finite at the origin, indicating the absence of singularities. We also explore the physical properties of the matter associated with these solutions. Due to its versatility, we suggest the possibility of using this approach as a tool to construct new physical solutions associated with regular black holes or other geometries of interest.

We study some properties of the extended phase space of a quantum-corrected Schwarzschild black hole surrounded by a perfect fluid. In particular we demonstrate that, due to the quantum correction, there exist first and second order phase transitions for a certain range of the state parameter of the perfect fluid, and we explicitly analyze some cases. Besides that, we describe the efficiency of this system as a heat engine and the effect of quantum corrections for different surrounding fluids.

The search for efficient materials for cleaning water is still being explored today. With this objective, pure hydroxyapatite (HAp) was prepared in this work as a ceramic matrix doped with 1, 3 and 5% magnesium by a microwave-assisted hydrothermal method (MAH) aimed at photocatalytic application under sunlight irradiation. XRD and FTIR analyses showed that only HAp was obtained from all the samples, and Rietveld refinement indicated a reduced crystallite size and increased microstrain after Mg doping. Nanorod-like morphologies were observed after analysis by SEM-FEG, with a decrease in the length and width of the particles after inserting the dopant. The UV‒Vis results revealed that the HAp bandgap decreased to 3.75 eV after doping. The photoluminescence spectra showed that oxygen vacancies were generated in the presence of Mg, which also caused an increase in the specific surface area of HAp. Photocatalytic tests were conducted with mixtures of methylene blue, crystal violet and malachite green dyes. After 120 min of sunlight irradiation, the sample with 3% Mg obtained the best results, achieving up to 94% degradation of the dyes. Furthermore, reusability tests showed that there was a small reduction in photocatalytic efficiency after five cycles, without structural changes in the photocatalyst. Inhibition tests showed that superoxides and holes are the active radicals, and tests with inorganic anions revealed that carbonates, nitrates and sulphates promote degradation, while phosphates reduce photocatalytic performance. This work highlights the promising alternative application of hydroxyapatite for simultaneous efficient photodegradation of different pollutants using sustainable energy. Graphical abstract

Abstract The intensified emission of greenhouse gases due to anthropogenic activities may drastically change the climate and reduce natural resource availability. In this context, conservation systems, such as agroforestry systems, can mitigate GHG emissions and allow the sustainable use of natural resources while maintaining ecological processes and economic and social development. We aimed to evaluate the spatial variability in bulk density, soil organic carbon, and SOC stocks in AFS and native forest sites in the Brazilian Amazon. The study sites are located in the municipality of Silves, state of Amazonas. We sampled one AFS site and one NF site in three layers of depth (0-0.1 m, 0.1-0.2 m, and 0.2-0.4m) in sampling grids with 64 equally interspaced sampling points. We analyzed soil traits using descriptive statistics and geostatistics. The AFS implemented 22 years before data collection in the study site contributed to the conservation of SOC stocks. Bulk density was similar between the AFS and the NF in all layers, indicating the absence of negative impacts of the AFS and possibly the recovery and maintenance of environmental quality in the previously disturbed study site. Both the AFS and the NF sites presented strong spatial dependence. Spatial patterns of SOC in the AFS may allow the definition of distinct management zones. The information provided by the geostatistical tools can be used by family farmers and managers of AFS in the region. Resumo A emissão intensificada de gases de efeito estufa devido a atividades antrópicas pode alterar drasticamente o clima e reduzir a disponibilidade de recursos naturais. Nesse contexto, sistemas de uso conservacionista, como sistemas agroflorestais, podem mitigar as emissões de GEE e permitir o uso sustentável dos recursos naturais, mantendo os processos ecológicos e o desenvolvimento econômico e social. Assim o objetivo do trbalho foi avaliar a variabilidade espacial na densidade do solo, carbono orgânico do solo e estoques de COS em locais de SAFs e floresta nativa na região central da Amazônia. Os locais de estudo localizam-se no município de Silves, Amazonas. Foram coletas amostras de solos em uma área de SAF e uma área sob NF em três profundidade (0-0,1 m, 0,1-0,2 m e 0,2-0,4 m) em grades amostrais com 64 pontos amostrais igualmente espaçados. Foram relizadas analises estatística descritiva e geoestatística. O SAF implementado 22 anos antes da coleta de dados no local de estudo contribuiu para a conservação dos estoques de COS. A densidade do solo foi semelhante entre o SAF e o NF em todas as camadas, indicando a ausência de impactos negativos do SAF e, possivelmente, a recuperação e manutenção da qualidade ambiental na área de estudo previamente perturbada. Tanto o SAF quanto o NF apresentaram forte dependência espacial. Padrões espaciais de SOC no SAF podem permitir a definição de zonas de manejo distintas. As informações fornecidas pelas ferramentas geoestatísticas podem ser utilizadas por agricultores familiares e gestores de SAF na região.

In this work, we investigate exact black string solutions in the context of f ( R ,  T ) gravity. Adopting the specific form f ( R , T ) = R + 2 χ T , we consider an anisotropic Kiselev fluid as the matter content and obtain static cylindrical solutions, which are then extended to the rotating case through a suitable coordinate transformation. The influence of the quintessence state parameter w q and the matter–geometry coupling constant χ on the geometry is analyzed. We examine the weak, null, and strong energy conditions, identifying the regions in the parameter space where they are satisfied. Furthermore, we apply the Hamilton–Jacobi method to study the tunneling of scalar particles across the event horizon and derive the corresponding Hawking temperature. The thermodynamic stability of the solutions is investigated by computing the heat capacity, and the conditions for phase transitions are discussed. The results provide a characterization of black strings in f ( R ,  T ) gravity surrounded by quintessence, highlighting the combined effects of anisotropic matter and modified gravity on their physical properties.

Earth, Venus, Mars and some extrasolar terrestrial planets 1 have a mass and radius that is consistent with a mass fraction of about 30% metallic core and 70% silicate mantle 2 . At the inner frontier of the Solar System, Mercury has a completely different composition, with a mass fraction of about 70% metallic core and 30% silicate mantle 3 . Several formation or evolution scenarios are proposed to explain this metal-rich composition, such as a giant impact 4 , mantle evaporation 5 or the depletion of silicate at the inner edge of the protoplanetary disk 6 . These scenarios are still strongly debated. Here, we report the discovery of a multiple transiting planetary system (K2-229) in which the inner planet has a radius of 1.165 ± 0.066 Earth radii and a mass of 2.59 ± 0.43 Earth masses. This Earth-sized planet thus has a core-mass fraction that is compatible with that of Mercury, although it was expected to be similar to that of Earth based on host-star chemistry 7 . This larger Mercury analogue either formed with a very peculiar composition or has evolved, for example, by losing part of its mantle. Further characterization of Mercury-like exoplanets such as K2-229 b will help to put the detailed in situ observations of Mercury (with MESSENGER and BepiColombo 8 ) into the global context of the formation and evolution of solar and extrasolar terrestrial planets. The abundance of metals in Mercury’s interior is unique among the rocky planets of the Solar System. The characterization of the ‘super-Mercury’ exoplanet presented in this paper will improve our understanding of how Mercury-like planets can form and evolve.

This work studies the relativistic quantum dynamics of scalar bosons in a spacetime containing both a cosmic string and a global monopole within the framework of Rainbow Gravity. An effective metric is constructed to describe the combined topological defects together with the energy-dependent deformation of spacetime. The Klein–Gordon equation is formulated in this background, including scalar, vector, and nonminimal couplings, and its solutions are obtained by separation of variables. Generalized Coulomb-type interactions are considered, allowing a unified analysis of scattering and bound states. The bound-state spectrum is determined from the poles of the corresponding S -matrix. Two specific choices of rainbow functions are examined, and their influence on the energy spectrum is analyzed through numerical calculations and, in suitable limits, analytical approximations. The results show how the interplay between topological defects and rainbow gravity corrections affects the spectral properties of scalar bosons, while known results are consistently recovered in appropriate limits.

This work investigates the dynamics of a charged scalar boson in the Melvin universe by solving the Klein–Gordon equation with minimal coupling in both inertial and non-inertial frames. Non-inertial effects are introduced through a rotating reference frame, resulting in a modified spacetime geometry and the appearance of a critical radius that limits the radial domain of the field. Analytical solutions are obtained under appropriate approximations, and the corresponding energy spectra are derived. The results indicate that both the magnetic field and non-inertial effects modify the energy levels, with additional contributions depending on the coupling between the rotation parameter and the quantum numbers. A numerical analysis is also presented, illustrating the behavior of the solutions for two characteristic magnetic field scales: one that may be considered extreme, of the order of the ones proposed to be produced in heavy-ion collisions, and another near the Planck scale.