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In dental implants, zirconia is well-known as a crown material due to its excellent acid and base resistances and appearance close to natural teeth. In addition, its extraordinary mechanical properties render zirconia to be a potential candidate as an implant component of a whole implanted tooth, if its biocompatibility can be improved to promote adhesion to natural hard tissues. This study aims to enhance the bioactivity of zirconia with the aim of improving its integration with gum bone. Hydroxyapatite is the major component of natural bone and is thus selected as the modifier to improve the bioactivity of zirconia. A series of zirconia/hydroxyapatite composites with varied compositions were prepared under different conditions in order to find the optimal composites for the target application. Various analytical technologies and mechanical tests are employed to characterise the structure and properties of resultant composites. Results show that the component ratio and sintering temperature have a significant influence on the composite properties. An increase in hydroxyapatite component tends to enhance bioactivity but decline mechanical strength. Composites containing 10 wt% of hydroxyapatite maintain sufficient mechanical strength under the optimal sintering conditions whilst possessing excellent bioactivity, demonstrating that hydroxyapatite-modified zirconia has the potential as dental implant materials. Sintering results suggest that mechanical strength is obtained at 1400 °C for 2 h for the composite containing 10 wt% of hydroxyapatite.

This work determined the spectral values in the 250–850 wavelength regions of the complex refractive index, n and k, for free-standing porous silicon (PS) and oxidized PS layers. These values were extracted from the experimental reflectance and transmittance spectra. One of the free-standing PS layers was fabricated with high porosity, and the other had low porosity. Thereafter, both layers were oxidized by dry oxidation to achieve a free-standing oxidized PS layer. The oxidation of the porous structures dramatically affects the optical properties of the free-standing layers, especially in the short wavelength Ultraviolet and Visible ranges, since the average transmittance enormously increases, reaching almost 90% at some specific points. Also, we found that the average value of the refractive index and extinction coefficient is higher for PS layers with lower porosity than those with higher porosity. The extinction coefficient and refractive index values are further reduced by oxidizing the free-standing PS layers in the 250–850 wavelength region. The reader can see a zero extinction coefficient value for the oxidized PS layer manufactured with high porosity. Our results show that due to a dry oxidation process in an air environment, the absorption coefficient can be reduced until reaching a value of zero. Due to that, it could be possible to design photonic crystals such as Microcavities, Fibonacci structures, waveguides, and Rugate filters without optical losses caused by light absorption in the Ultraviolet and Visible regions. Pore diameter, thickness and Energy-dispersive X-ray spectroscopy (EDS) elemental spectrum of two different PS layers were determined.

As an important aquaculture species and research model, Nile tilapia (Oreochromis niloticus) has not yet been systematically studied for the isolation, culture, and in vitro gene manipulation techniques of primary cells from various tissues. This study aimed to explore methods for isolating primary cells from various tissues, as well as developing in vitro gene manipulation techniques in Nile tilapia. Four different Nile tilapia tissues were enzymatically digested and separated using trypsin or collagenase. Collagenase (0.1%) was used for the digestion of the gonads, liver, and heart, while trypsin (0.25%) showed better adhesion efficiency for spleen tissue. Moreover, we assessed EGFP fluorescence intensity and cell survival rates following transfection with empty siRNA (siRNA-NC), lentivirus (LV-NC), and six adeno-associated virus (AAV-NC) serotypes (AAV2-NC, AAV5-NC, AAV6-NC, AAV8-NC, AAV9-NC, AAV-DJ-NC) in gonadal cells. The results demonstrated that cells transfected with siRNA-NC and LV-NC showed the highest levels of green fluorescent protein expression and survival rates in primary gonadal cells, compared to AAC-NC. Subsequently, we knocked down the Kdm6bb gene in Nile tilapia primary gonadal cells by transfecting them with LV-Kdm6bb and siRNA-Kdm6bb. qPCR and immunofluorescence analyses demonstrated a significant reduction in Kdm6bb mRNA levels following transfection with siRNA-Kdm6bb compared to siRNA-NC, and with LV-Kdm6bb compared to LV-NC. This study offers valuable tools for the validation of primary cell isolation and in vitro molecular regulatory mechanisms and functions in Nile tilapia.

In this paper, a metal–insulator–metal (MIM) array nanostructure consisting of a bowtie aperture and cylindrical holes is proposed as a field amplifier. This hybrid array consists of a grating film made of gold in which some cylindrical holes are replaced with a bowtie aperture, sapphire substrate, and finally a metal film. The array of cylindrical holes acting as a two-dimensional grating can effectively excite propagating surface plasmon polariton modes along a metal film, but the electric field enhancement inside it is relatively weak. On the other hand, the bowtie aperture, with its sharp corners and small gap, can provide a greater intensity enhancement factor within its gap. The combination of these two MIM nanostructures forms a strong coupling between the propagating and localized surface plasmons, leading to an improvement in field confinement in the bowtie aperture in the sub-diffraction limit and its magnitude increase of 115 times. This effective enhancement can be used in plasmonic sensors, lasers, SERS, etc., applications.

Ambient air pollution is a global problem that adversely affects human health and causes premature death. In this study, for the first time, the air quality of Körfez region in Kocaeli, an industrialized city in Turkey, was investigated during 2019–2023. The annual and monthly variations of PM₁₀, PM_2.5, SO₂, NO_2, and O₃ concentrations in the region were investigated. Average daily maximum 8 h average concentration values for O₃ were calculated due to the high average O₃ concentration, especially in the months representing the summer season (June, July, and August). The concentration values of five air pollutants were compared with the limit values specified in the 2005 World Health Organization Air Quality Guidelines (2005 WHO AQG), 2021 WHO AQG, and Turkish national legislation. Pearson correlation analysis was performed to determine the relationship between the concentrations of air pollutants. The annual average PM₁₀ and PM_2.5 concentrations exceeded the limit values recommended by WHO during 2019–2023. In 2022 and 2023, the annual average PM₁₀ concentrations were 2.54 and 2.53 times higher than the limit values in the 2021 WHO AQG, while PM_2.5 concentrations were 3.4 and 3.7 times higher. Average NO₂ concentration was 3.58 and 2.71 times higher than the 2021 WHO AQG in 2022 and 2023, respectively. The average SO₂ concentration (< 13.2 µg/m³) did not exceed both WHO and national limit values for five years. The study demonstrated that in the study area exposure to PM₁₀, PM_2.5 and NO₂ pollution is higher during the colder seasons, while exposure to O₃ pollution is higher during the summer season. Especially in July and August, the number of exceedances of the daily maximum 8-h O₃ concentration of 100 µg/m³ was higher. There were positive strong-very strong correlations between PM₁₀-PM_2.5, PM₁₀-NO_2, and PM_2.5-NO_2, while there were negative and moderate correlations between PM_2.5-O₃ and NO₂-O₃. Considering the concentration of air pollutants in the Körfez region and the limit values for air pollutants, the people in this region face serious health risks, especially respiratory diseases, due to PM10, PM2.5, NO₂ and O₃ pollution. These air pollutants may pose an additional health risk, especially for individuals with respiratory diseases in this region.

Graphical Abstract

This work carries out a study of the heterogeneous photocatalysis process using TiO₂ and the composite TiO₂/iron oxides as catalysts, in order to perform the degradation of propylparaben. The composite produced aims to maintain the catalytic capacity of the precursor material, while improving the recovery of the material after its application. Magnetic removal is a quick and efficient way of reapplying the catalyst. The photocatalysts produced were characterized by XRD, FTIR, SEM, TEM/EDS, PL and UV–vis. The composite obtained showed the predominant crystalline phases anatase and magnetite, as well as photocatalytic activity which was increased by the decrease of the material bandgap, promoted by the materials combination. The materials efficiency was determined under ultraviolet irradiation through the degradation of propylparaben, in which the highest efficiency was obtained with the composite was the removal of 16.2 ppm, around 80.83% from 20 ppm, and for pure TiO₂ it was the degradation of 4.7 ppm, around 94.52% from 5 ppm of propylparaben. These findings present a valuable alternative to a highly effective photocatalyst that can be magnetically removed from the treated solution and be reused in another treatment run.

One of the possible ways to test gravity theories and get constraints on parameters of a gravity theory and a black hole is based on studies of black hole shadow applying Event Horizon Telescope (EHT) data from the shadow sizes of M87* and Sgr A*. In this sense, we study the shadow of rotating charged black holes in Einstein–Maxwell scalar (EMS) theory. First, we obtain a rotating EMS black hole solution and analyze the horizon properties. We derive the effective potential for the circular motion of photons along null geodesics around the rotating black hole and obtain the black hole shadow using celestial coordinates. The effects of the black charge and spin and EMS theory parameters on the shape of the black hole shadow, its radius, and distortion parameters are analyzed in detail. We have obtained upper and lower limits for spin and black hole charges of Sgr A* and M87* using their shadow size for various values of EMS parameters. Lastly, we computed and examined the standard shadow radius, equatorial, and polar quasinormal modes using the geometric-optic relationship between the parameters of the quasinormal mode and the conserved values along the geodesics.

In this paper, we study the scalar and Dirac fields perturbation of Schwarzschild-de Sitter-like black hole in bumblebee gravity model. The effective potentials, greybody factors and quasinormal modes of the black hole are investigated by using the Klein–Gordon equation and Dirac equation. To compute the greybody factors for scalar and Dirac fields, we use the general method of rigorous bound. We also investigate the quasinormal mode using the third order WKB approximation method and Pöschl–Teller fitting method. The impact of Lorentz invariance violation parameter L and cosmological constant (varLambda ) to the effective potential, greybody factors and quasinormal modes are analyzed for different modes. Increasing the parameters (varLambda ) and L lower the effective potentials and consequently increases the rigorous bound on the greybody factors. Our findings show that the oscillation frequency and the damping rate decrease with increasing L. We analyze the Hawking temperature, power spectrum and sparsity of Hawking radiation. Both the peak of power spectrum and total power emitted decrease with increasing L. The effect of L on the shadow radius is also discussed.

Highlights

Alum mine pollution is becoming a great threat to the health of ecosystem and human beings. Phytoremediation is an economic and green strategy to treat mine pollution, but its efficiency is frequently compromised by the mine hazardous pollutant-induced attenuation of plant growth. In this study, we introduced rice straw biochar to investigate its effect on plant growth, rhizosphere microbiome composition and the quality of soil and groundwater. Indoor culturing experiments showed that the biochar improved seed germination and plant heights in the soils sampled from the alum mine. In situ phytoremediation was then performed in the long-term alum mining area, i.e., the Fanshan alum mine in Anhui Province, China. As revealed by microbiome analysis, the biochar with multiple plants drastically changed the composition of rhizosphere soil microbiome, leading to the increase in the relative abundance of rhizosphere beneficial bacteria, e.g., Rhizobiales, Xanthomonadales and Bacillales. Furthermore, the biochar and the remediation plants improved the quality of both mine soil and groundwater. Under this multiple treatment for 1 year, the soil total nitrogen levels increased from 0.038 g/kg to 1.08 g/kg, and the soil organic matters from 1.72 g/kg to 9.50 g/kg. Meanwhile, the soil heavy metal levels were remarkably reduced. More strikingly, in the mine groundwater after 1-year or 2-year of treatment, the levels of hazardous metal elements, e.g., copper, fluorine, and cadmium, drastically decreased. This study developed a biochar-based phytoremediation strategy to efficient treat the pollution of alum mine area for in situ application.