Search Results (42)

The luminescent properties of cerium-doped barium aluminate (BaAl₂O₄) samples with varying Ce concentrations (0–1.1 mol%) prepared either in an air or nitrogen-reduced atmosphere are presented. This work provides the first detailed comparison of the material’s structural, luminescent, and chromatic properties at different doping levels and thermal treatments. X-ray diffraction analysis confirmed the hexagonal crystal structure of barium aluminate. Samples treated in an air atmosphere exhibited crystallite sizes of 58.5 nm for undoped samples and 45.7 nm for doped samples. In contrast, those treated under nitrogen showed smaller crystallite sizes, i.e., 39.8 nm for undoped and 42.3 nm for doped samples, respectively. XPS analysis indicated that the nitrogen-reduced atmosphere minimized Ce oxidation, favoring the presence of Ce³⁺. The bandgap values of the material were 4.0 eV and 5.6 eV for the air and for the nitrogen atmosphere, respectively. Photoluminescence spectra showed maxima at 357 nm (air) and 386 nm (nitrogen), attributed to 4f-5d transitions of Ce. The samples under air atmosphere showed longer lifetimes values (0.94 ns) compared to those in a nitrogen atmosphere (0.40 ns). These results suggest that thermal treatment in an air atmosphere promoted better structural order and higher photoluminescence efficiency, while treatment in a nitrogen-reduced atmosphere increased defect formation, shortening the lifetime. Chromaticity coordinate analysis showed that the cerium ion dopant influenced the blueish emission color in both samples. Full article

In this study, we highlight the use of the alkaline earth metal barium (Ba) for the impregnation of Ag₃PO₄ (AgP). AgP was synthesized via co-precipitation and subsequently impregnated with a Ba²⁺-containing solution, followed by hydrothermal treatment to obtain Ba-AgP. The addition of barium significantly influenced both the crystallinity and crystallite size. Ba impregnation enhanced the crystallinity of AgP and promoted the growth of its crystallites. It was confirmed that Ba²⁺ was homogeneously distributed on the surface of AgP, with only a slight effect on particle shape. Ba-impregnated Ag₃PO₄ (Ba-AgP) exhibited improved photocatalytic activity for the degradation of methyl orange (MO) under visible light compared to bare AgP. The optimal impregnation concentration of Ba²⁺ was determined to be 6%. This enhancement is attributed to the role of Ba²⁺ in facilitating the separation of photogenerated electron–hole pairs, which also contributed to the improved stability of AgP. The active species h⁺, ·OH, and O₂·⁻ were all identified as essential for the MO degradation process, with h⁺ being the most significant contributor. Full article

Puerarin, a flavonoid compound present in the roots of radix puerariae, contributes to the development of tissues such as bone and nerve, but its role in skeletal muscle regeneration remains unclear. In this study, we employed C2C12 myoblasts and barium chloride (BaCl₂)-based muscle injury models to investigate the effects of puerarin on myogenesis. Our study showed that puerarin stimulated the migration and differentiation of myoblasts in vitro. For the mechanism study, we found that puerarin’s influence on cell migration was associated with the activation of FAK signaling; additionally, puerarin induced myoblast differentiation by upregulating the PI3K/AKT pathway. We also found that puerarin treatment could improve muscle regeneration following muscle injury. Taken together, our data indicate that puerarin facilitated myogenesis by promoting migration and differentiation, which suggests puerarin as a new candidate drug for the treatment of muscle loss diseases. Full article

Amniotic fluid is a complex and dynamic biological matrix that surrounds the fetus during the pregnancy. From this fluid, is possible to isolate various cell types with particular interest directed towards stem cells (AF-SCs). These cells are highly appealing due to their numerous potential applications in the field of regenerative medicine for tissues and organs as well as for treating conditions such as traumatic or ischemic injuries to the nervous system, myocardial infarction, or cancer. AF-SCs, when subcultured in the presence of basic Fibroblast Growth Factor (bFGF), have been shown to survive and migrate when transplanted into the striatum of the rat brain, exhibiting behavior characteristics of neuronal/glial progenitor cells. In this work, we performed an electrophysiological characterization to ascertain the propensity of AF-SCs to differentiate into glial and neuronal cells by bFGF. By using patch clamp technique we characterized a fibroblast-like morphology that display a barium-sensitive inward-rectifying potassium current (Kir) and calcium-activated potassium currents (KCa). The electrophysiological and calcium dynamics of histamine, a marker of undifferentiated neural progenitors, was further studied. Histamine promoted intracellular calcium increase by Fura-2 recording and calcium-activated potassium current activation with a similar temporal profile in AF-SC. The data presented in this paper ultimately confirm the expression in AF-SCs of the Kir and KCa currents, also showing regulation by endogenous stimuli such as histamine for the latter. Full article

This study proposes an innovative method for the harmless treatment of barium slag using the industrial by-product Flue Gas Desulfurization Gypsum. Barium slag is a by-product of the barium carbonate production process, and due to its high content of barium ions and corrosive properties, it poses a significant threat to the environment and human health. It is classified as barium-containing hazardous waste (code HW47) in China. In this study, barium slag was optimally combined with FGD gypsum, utilizing a synergistic precipitation mechanism to solidify the easily leachable barium ions and form stable sulfate minerals. Mechanical and heavy metal leaching tests showed that the harmlessly treated barium slag had a certain compressive strength, and the concentration of barium ions in the leachate was below the national hazardous waste identification standards (100 mg/L) and the drinking water quality standards (0.7 mg/L). Microstructural analysis using X-ray diffraction, Fourier Transform Infrared Spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy indicated that FGD gypsum promotes the solidification of barium slag, and through the synergistic precipitation mechanism, low-solubility barium sulfate minerals are formed. This treatment method also has a low cost and good potential for resource utilization, providing effective technical support for the green treatment of industrial waste. Full article

A simple and innovative method was introduced for the production of green and recoverable flame-retardant cotton fabrics, where sulfonated cotton fabric (COT-SC) was synthesized by oxidizing cotton fabric with sodium periodate, followed by a sulfonation step with sodium bisulfite to provide active sites, which further chelated barium ions (Ba²⁺) to achieve flame retardancy. The morphological and structural characterizations of the fabricated cotton fabrics (COT-SC-Ba) demonstrated that the cleavage of C₂-C₃ free hydroxy groups within the cellulose macromolecule was chemically modified for grafting a considerable number of sulfonic acid groups, and Ba²⁺ ions were effectively immobilized on the macromolecule of the cotton fabric through a chelation effect. Results from cone calorimeter tests (CCTs) revealed that COT-SC-Ba became nonflammable, displayed a delayed ignition time, and decreased the values of the heat release rate (HRR), total smoke release (TSR), effective heat of combustion (EHC), and CO/CO₂ ratio. TG/DTG analysis demonstrated that COT-SC-Ba possessed greater thermal stability, fewer flammable volatiles, and more of a char layer during burning than that of the original cotton fabric. Its residual mass was increased from 0.02% to 26.9% in air and from 8.05% to 26.76% in N₂, respectively. The COT-SC-Ba not only possessed a limiting oxygen index (LOI) of up to 34.4% but could also undergo vertical burning tests evidenced by results such as the non-afterflame, non-afterglow, and a mere 75 mm char length. Those results demonstrated that the combination of SO₃⁻ and Ba²⁺ promoted the formation of a char layer. Moreover, cotton fabric regained its superior flame retardancy after being washed and re-chelated with Ba²⁺. Additional characteristics of the cotton fabric, such as the rupture strength, white degree, and hygroscopicity, were maintained at an acceptable level. In conclusion, this research can offer a fresh perspective on the design and development of straightforward, efficient, eco-friendly, and recoverable fire-retardant fabrics. Full article

Ammonia synthesis is one of the most important chemical reactions. Due to thermodynamic restrictions and the reaction requirements of the current commercial iron catalysts, it is also one of the worst reactions for carbon dioxide emissions and energy usage. Ruthenium-based catalysts can substantially improve the environmental impact as they operate at lower pressures and temperatures. In this work, we provide a screening of more than 40 metals as possible promoter options based on a Ru/Pr₂O₃ catalyst. Cesium was the best alkali promoter and was held constant for the series of double-promoted catalysts. Ten formulations outperformed the Ru-Cs/PrO_x benchmark, with barium being the best second promoter studied and the most cost-effective option. Designs of experiments were utilized to optimize both the pretreatment conditions and the promoter weight loadings of the doubly promoted catalyst. As a result, optimization led to a more than five-fold increase in activity compared to the unpromoted catalyst, therefore creating the possibility for low-ruthenium ammonia synthesis catalysts to be used at scale. Further, we have explored the roles of promoters using kinetic analysis, X-ray Photoelectron Spectroscopy (XPS), and in situ infrared spectroscopy. Here, we have shown that the role of barium is to act as a hydrogen scavenger and donor, which may permit new active sites for the catalyst, and have demonstrated that the associative reaction mechanism is likely used for the unpromoted Ru/PrO_x catalyst with hydrogenation of the triple bond of the dinitrogen occurring before any dinitrogen bond breakage. Full article

Improving fracture toughness, electrical conductivity, and biocompatibility has consistently presented challenges in the development of artificial bone replacement materials. This paper presents a new strategy for creating high-performance, multifunctional composite ceramic materials by doping graphene oxide (GO), which is known to induce osteoblast differentiation and enhance cell adhesion and proliferation into barium calcium zirconate titanate (BCZT) ceramics that already exhibit good mechanical properties, piezoelectric effects, and low cytotoxicity. Using fast hot-pressed sintering under vacuum conditions, (1 − x)(Ba_0.85Ca_0.15Zr_0.1Ti_0.9)O₃₋xGO (0.2 mol% ≤ x ≤ 0.5 mol%) composite piezoelectric ceramics were successfully synthesized. Experimental results revealed that these composite ceramics exhibited high piezoelectric properties (d₃₃ = 18 pC/N, k_p = 62%) and microhardness (173.76 HV_0.5), meeting the standards for artificial bone substitutes. Furthermore, the incorporation of graphene oxide significantly reduced the water contact angle and enhanced their wettability. Cell viability tests using Cell Counting Kit-8, alkaline phosphatase staining, and DAPI staining demonstrated that the GO/BCZT composite ceramics were non-cytotoxic and effectively promoted cell proliferation and growth, indicating excellent biocompatibility. Consequently, with their superior mechanical properties, piezoelectric performance, and biocompatibility, GO/BCZT composite ceramics show extensive potential for application in bone defect repair. Full article

To clarify how the digestive tract of the weatherloach, Misgurnus anguillicaudatus, serves a dual function of digestion and respiration simultaneously, the histological structures of its digestive tract, the passage of digesta and air passing through its intestine and the rate of intestinal evacuation have been studied. The results indicate that the digestive tract is divided into five functional regions, i.e., esophagus, anterior intestine, middle intestine, posterior intestine and rectum. The diverse intestinal structures have the specialized function of coordinating digestion and respiration. An X-ray barium meal examination showed in the normal breathing state, the contents of the intestine are diffusely semifluid, and air is distributed as bubbles in the dorsal intestine 2 h after feeding. After 5 h, the contents accumulated in the mid and posterior intestine, and gas flowed above the contents as bundles. After 8 h, the intestinal food was basically evacuated. In the intestinal air-breathing restricted group, the contents of the intestine remained diffuse, and a large number of digesta entered and remained in the rectum after 5 h. After the inhibition was relieved, the contents of the rectum were rapidly discharged. Measurement of the intestinal evacuation rate in the intestine showed that the evacuation of the intestinal contents lagged behind that of the normal group in the air-breathing restricted group. Compared to the normal state and inhibited GAB (gastrointestinal air breathing), we could deduce that GAB could promote the movement of the intestine. Full article

We report an investigation of catalyst performance for the decomposition of ammonia under industrially relevant conditions (high temperatures of up to 800 °C and an elevated pressure of 5 bar) with further emphasis on their stability at high reaction temperatures. The catalysts were applied and tested as coatings in 500 µm wide channels of microreactors. Nickel-based catalysts were studied and compared to a ruthenium-based catalyst supported on SiO₂. The effect of the support on the catalytic performance was investigated, and CeO₂-supported nickel catalysts were found to exhibit the highest activity. Promoters were applied to increase the NH₃ decomposition activity of the Ni/CeO₂ catalysts. The addition of cesium led to a slight reduction in activity, while lanthanum, calcium, and barium doping resulted in increased activity. In particular, the barium-doped Ni/CeO₂ catalyst showed very high ammonia conversion and closed the activity gap with respect to ruthenium catalysts at reactor temperatures of 650 °C and higher. The hydrogen production rates achieved in this work were compared to values in the literature and were shown to exceed values found earlier for both nickel- and ruthenium-based catalysts. Furthermore, the ruthenium-based catalysts under investigation were rapidly deactivated at 700 °C, while the nickel-based catalysts did not show deactivation after 220 h on time on stream at 700 °C. Full article

Assessing the biocompatibility of endodontic root-end filling materials through cell line responses is both essential and of utmost importance. This study aimed to the cytotoxicity of the type of cell death through apoptosis and autophagy, and odontoblast cell-like differentiation effects of MTA, zinc oxide–eugenol, and two experimental Portland cements modified with bismuth (Portland Bi) and barium (Portland Ba) on primary cell cultures. Material and methods: The cells corresponded to human periodontal ligament and gingival fibroblasts (HPLF, HGF), human pulp cells (HPC), and human squamous carcinoma cells from three different patients (HSC-2, -3, -4). The cements were inoculcated in different concentrations for cytotoxicity evaluation, DNA fragmentation in electrophoresis, apoptosis caspase activation, and autophagy antigen reaction, odontoblast-like cells were differentiated and tested for mineral deposition. The data were subject to a non-parametric test. Results: All cements caused a dose-dependent reduction in cell viability. Contact with zinc oxide–eugenol induced neither DNA fragmentation nor apoptotic caspase-3 activation and autophagy inhibitors (3-methyladenine, bafilomycin). Portland Bi accelerated significantly (p < 0.05) the differentiation of odontoblast-like cells. Within the limitation of this study, it was concluded that Portland cement with bismuth exhibits cytocompatibility and promotes odontoblast-like cell differentiation. This research contributes valuable insights into biocompatibility, suggesting its potential use in endodontic repair and biomimetic remineralization. Full article

Barium titanate (BaTiO₃) piezoelectric ceramic may be a potential alternative for promoting osseointegration due to its piezoelectric properties similar to bone electric potentials generated in loading function. In this sense, the aim of this in vitro study was to evaluate the cellular response of human osteoblasts and gingival fibroblasts as well as the impact on S. oralis when in contact with BaTiO₃ functionalized zirconia implant surfaces with piezoelectric properties. Zirconia discs with BaTiO₃ were produced and contact poling (piezo activation) was performed. Osteoblasts (hFOB 1.19), fibroblasts (HGF hTERT) and S. oralis were culture on discs. Cell viability and morphology, cell differentiation markers, bacterial adhesion and growth were evaluated. The present study suggests that zirconia composite surfaces with the addition of piezoelectric BaTiO₃ are not cytotoxic to peri-implant cells. Also, they seem to promote a faster initial osteoblast differentiation. Moreover, these surfaces may inhibit the growth of S. oralis by acting as a bacteriostatic agent over time. Although the piezoelectric properties do not affect the cellular inflammatory profile, they appear to enable the initial adhesion of bacteria, however this is not significant over the entire testing period. Furthermore, the addition of non-poled BaTiO₃ to zirconia may have a potential reduction effect on IL-6 mediated-inflammatory activity in fibroblasts. Full article

The aim of this study was to develop an experimental composite resin with the addition of myristyltrimethylammonium bromide (MYTAB) and α -tricalcium phosphate (α-TCP) as an antibacterial and remineralizing material. Experimental composite resins composed of 75 wt% Bisphenol A-Glycidyl Methacrylate (BisGMA) and 25 wt% Triethylene Glycol Dimethacrylate (TEGDMA) were produced. Some 1 mol% Trimethyl benzoyl-diphenylphosphine oxide (TPO) was used as a photoinitiator, and butylated hydroxytoluene (BTH) was added as a polymerization inhibitor. Silica (1.5 wt%) and barium glass (65 wt%) particles were added as inorganic fillers. For remineralizing and antibacterial effect, α-TCP (10 wt%) and MYTAB (5 wt%) were incorporated into the resin matrix (α-TCP/MYTAB group). A group without the addition of α-TCP/MYTAB was used as a control. Resins were evaluated for their degree of conversion (n = 3) by Fourier Transform Infrared Spectroscopy (FTIR). The flexural strength (n = 5) was assessed based on ISO 4049:2019 requirements. Microhardness was assessed to calculate softening in solvent (n = 3) after ethanol immersion. The mineral deposition (n = 3) was evaluated after immersion in SBF, while cytotoxicity was tested with HaCaT cells (n = 5). Antimicrobial activity (n = 3) was analyzed against S. mutans. The degree of conversion was not influenced by the antibacterial and remineralizing compounds, and all groups reached values > 60%. The α-TCP/MYTAB addition promoted increased softening of polymers after immersion in ethanol and reduced their flexural strength and the viability of cells in vitro. A reduction in S. mutans viability was observed for the α-TCP/MYTAB group in biofilm formation and planktonic bacteria, with an antibacterial effect > 3log₁₀ for the developed materials. Higher intensity of phosphate compounds on the sample’s surface was detected in the α-TCP/MYTAB group. The addition of α-TCP and MYTAB promoted remineralizing and antibacterial effects on the developed resins and may be a strategy for bioactive composites. Full article

The electrochemical reduction of molecular oxygen is a fundamental process in Solid Oxide Fuel Cells and requires high efficiency cathode materials. Two La_0.25Ba_0.25Sr_0.5Co_0.8Fe_0.2O_3−δ-based perovskite compounds were prepared by solution combustion synthesis, and characterized for their structural, microstructural, surface, redox and electrochemical properties as potential cathodes in comparison with Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ and La_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ perovskites. Results highlighted that calcination at 900 °C led to a “bi-perovskite heterostructure”, where two different perovskite structures coexist, whereas at higher calcination temperatures a single-phase perovskite was formed. The results showed the effectiveness of the preparation procedures in co-doping the A-site of perovskites with barium and lanthanum as a strategy to optimize the cathode’s properties. The formation of nanometric heterostructure co-doped in the A-site evidenced an improvement in oxygen vacancies’ availability and in the redox properties, which promoted both processes: oxygen adsorption and oxygen ions drift, through the cathode material, to the electrolyte. A reduction in the total resistance was observed in the case of heterostructured material. Full article

The current work focuses on the photo degradation of organic pollutants, particularly methylene blue (MB) dye, and the production of hydrogen as green energy using a composite of silver phosphate Ag₃PO₄ (AP) and barium oxide/silver phosphate BaO@Ag₃PO₄ (APB) as a photocatalyst. This composite was successfully synthesized using a chemical co-precipitation approach. The physicochemical properties of the obtained samples were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis/DRS), and photoluminescence (PL) spectrophotometry. From XRD, the average crystallite sizes of AP and APB are 39.1 and 46 nm, respectively, with a homogeneous morphology detected by SEM. UV and PL experiments showed that the compound is active under visible light, with an improvement in the lifetimes of the electrons and the holes in the presence of BaO with Ag₃PO₄. The as-synthesized APB photocatalyst sample showed a remarkably high degradation efficiency of MB (20 ppm, 50 mL) of around 94%, with a hydrogen production yield of around 7538 μmol/(h·g), after 120 min of illumination, which is greater than the degradation efficiency of the AP photocatalyst sample, which was about 88%. The high photodegradation efficiency was attributed to the electronic promotion effect of the BaO particles. The APB composite demonstrated an increased photocatalytic performance in effectively degrading an organic dye (MB) with no secondary pollutants when exposed to visible light irradiation. Full article