Search Results (15)

The aim of this study was to experimentally assess the luminescence efficiency of a cerium fluoride (CeF₃) inorganic scintillator in crystal form as a possible alternative to high-luminescence but hygroscopic cerium bromide (CeBr₃). The experiments were performed under typical diagnostic radiology X-rays (50–140 kVp). Parameters such as the crystal’s absolute luminescence efficiency (AE) and the spectral matching with a series of optical detectors were examined. The replacement of bromine with fluorine appeared to drastically reduce the AE of CeF₃ compared to CeBr₃ and other commercially available inorganic scintillators such as bismuth germanate (Bi₄Ge₃O₁₂-BGO). CeF₃ reaches a maximum luminescence efficiency value of only 0.8334 efficiency units (EUs) at 140 kVp, whereas the corresponding values for CeBr₃ and BGO were 29.49 and 3.41, respectively. Furthermore, the emission maximum (at around 313 nm) moved towards the lower part of the visible spectrum, making CeF₃ suitable for spectral coupling with various photocathodes and photomultipliers applied in nuclear medicine detectors, but completely unsuitable for spectral matching with CCDs and CMOS. The obtained luminescence efficiency results denote that CeF₃ cannot be applied in medical imaging applications covering the range 50–140 kVp; however, examination of its luminescence output in the nuclear medicine energy range (~70 to 511 keV) could reveal possible applicability in these modalities. Full article

Gamma-ray bursts (GRBs) are intense and short-lived cosmic explosions. Miniaturised CubeSat-compatible instruments for the study of GRBs are being developed to help bridge the gap in large missions and assist in achieving full sky coverage. CubeSats are small, compact satellites conforming to a design standard and have transformed the space industry. They are relatively low-cost and are developed on fast timescales, which has provided unparalleled access to space. This paper focuses on GMOD, the gamma-ray module, onboard the 2U CubeSat EIRSAT-1, launched on December 1st 2023. GMOD is a scintillation-based instrument with a cerium bromide crystal coupled to an array of sixteen silicon photomultipliers, designed for the detection of GRBs. The characterisation of GMOD in the spacecraft, along with the validation of an updated spacecraft MEGAlib model is presented and this approach can be followed by other CubeSats with similar science goals. The energy resolution of the flight model is 7.07% at 662 keV and the effective area peaks in the tens to hundreds of keV, making it a suitable instrument for the detection of GRBs. An investigation into the instrument’s angular response is also detailed. The results from this characterisation campaign are a benchmark for the instrument’s performance pre-launch and will be used to compare with the detector’s performance in orbit. Full article

The ion doping of mesoporous silica nanoparticles (MSNs) has played an important role in revolutionizing several materials applied in medicine and dentistry by enhancing their antibacterial and regenerative properties. Mineral trioxide aggregate (MTA) is a dental material widely used in vital pulp therapies with high success rates. The aim of this study was to investigate the effect of the modification of MTA with cerium (Ce)- or calcium (Ca)-doped MSNs on the biological behavior of human gingival fibroblasts (hGFs). MSNs were synthesized via sol–gel, doped with Ce and Ca ions, and mixed with MTA at three ratios each. Powder specimens were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Biocompatibility was evaluated using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay following hGFs’ incubation in serial dilutions of material eluates. Antioxidant status was evaluated using Cayman’s antioxidant assay after incubating hGFs with material disc specimens, and cell attachment following dehydration fixation was observed through SEM. Material characterization confirmed the presence of mesoporous structures. Biological behavior and antioxidant capacity were enhanced in all cases with a statistically significant increase in CeMTA 50.50. The application of modified MTA with cerium-doped MSNs offers a promising strategy for vital pulp therapies. Full article

Sunset Yellow FCF (SY FCF) is one of the widely used synthetic azo dyes in the food industry whose content has to be controlled for safety reasons. Electrochemical sensors are a promising tool for this type of task. A voltammetric sensor based on a combination of tin and cerium dioxide nanoparticles (SnO₂–CeO₂ NPs) with surfactants has been developed for SY FCF determination. The synergetic effect of both types of NPs has been confirmed. Surfactants of various natures (sodium lauryl sulfate (SLS), Brij^® 35, and hexadecylpyridinium bromide (HDPB)) have been tested as dispersive media. The best effects, i.e., the highest oxidation currents of SY FCF, have been observed in the case of HDPB. The sensor demonstrates a 4.5-fold-higher electroactive surface area and a 38-fold-higher electron transfer rate compared to the bare glassy carbon electrode (GCE). The electrooxidation of SY FCF is an irreversible, two-electron, diffusion-driven process involving proton transfer. In differential pulse mode in Britton–Robinson buffer (BRB) pH 2.0, the sensor gives a linear response to SY FCF from 0.010 to 1.0 μM and from 1.0 to 100 μM with an 8.0 nM detection limit. The absence of an interferent effect from other typical food components and colorants has been shown. The sensor has been tested on soft drinks and validated with the standard chromatographic method. Full article

The present study focuses on the electrochemical performance of polyethylene oxide (PEO)-polymethyl methacrylate (PMMA) blended plasticized nanocomposite solid polymer electrolytes (BPNSPEs) amid cadmium bromide (CdBr₂) as a dopant salt along with a cerium oxide (CeO₂) nanofiller. Incredibly thin nanofilms of BPNSPE were signalized through distinct methods of working in characterization studies, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy and scanning electron micrography (SEM). The X-ray diffractograms (XRDs) confirmed the formation of the polymer electrolyte (PE) as well as a decrease in the degree of crystalline characteristics in the BPNSPE sample, and the particle dimension was calculated via the Debye–Scherer equation. The structural changes and formation of complexes were inspected by Fourier-transform infrared spectroscopy (FT-IR), and ocular absorbance scrutiny was accomplished by ultraviolet visible spectroscopy, whereas the morphological structure was interpreted by scanning electron microg-graphical images. The existing work is intended to increase the awareness of the significance of CeO₂ nanofillers with the BPNSPE arrangement, which is suitable for batteries and ionic devices. Full article

There is a scarcity of freshwater resources and their quality is deteriorating. As a result, meeting human needs is getting more and more challenging. Additionally, significant health problems are brought on by a shortage of freshwater. Therefore, finding a sustainable alternative technique for producing clean water is necessary. Solar distillation is one of the methods that can be implemented to enhance the overall production of pure water. In this work, a hybrid nanofluid was prepared using a two-step method with cerium oxide (CeO₂) nanoparticles and multi-walled carbon nanotubes (MWCNTs) in a ratio of 80:20. The concentrations of hybrid nanofluids investigated were 0.02%, 0.04%, and 0.06%. The surfactant cetyltrimethylammonium bromide (CTAB) was used to keep the hybrid nanofluid stable. The studies were carried out over three days in both conventional and modified stills at a constant depth of 1 cm of hybrid nanofluid. The modified still (MS) achieved a maximum production of 1430 mL compared to the conventional still’s (CS) maximum output of 920 mL. The CPL (Cost per liter) for MS was USD 0.039, and for CS, it was USD 0.045. The levels of TDS in the MS and CS were 96.38% and 92.55% lower than those in saline water. The fluoride ion level of saline water was 0.635 mg/L, whereas the distilled water of MS and CS are 0.339 mg/L and 0.414 mg/L, respectively. Full article

Food quality is mainly affected by oxygen through oxidative reactions and the proliferation of microorganisms, generating changes in its taste, odor, and color. The work presented here describes the generation and further characterization of films with active oxygen scavenging properties made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) loaded with cerium oxide nanoparticles (CeO₂NPs) obtained by electrospinning coupled to a subsequent annealing process, which could be used as coating or interlayer in a multilayer concept for food packaging applications. The aim of this work is to explore the capacities of these novel biopolymeric composites in terms of O₂ scavenging capacity, as well as antioxidant, antimicrobial, barrier, thermal, and mechanical properties. To obtain such biopapers, different ratios of CeO₂NPs were incorporated into a PHBV solution with hexadecyltrimethylammonium bromide (CTAB) as a surfactant. The produced films were analyzed in terms of antioxidant, thermal, antioxidant, antimicrobial, optical, morphological and barrier properties, and oxygen scavenging activity. According to the results, the nanofiller showed some reduction of the thermal stability of the biopolyester but exhibited antimicrobial and antioxidant properties. In terms of passive barrier properties, the CeO₂NPs decreased the permeability to water vapor but increased the limonene and oxygen permeability of the biopolymer matrix slightly. Nevertheless, the oxygen scavenging activity of the nanocomposites showed significant results and improved further by incorporating the surfactant CTAB. The PHBV nanocomposite biopapers developed in this study appear as very interesting constituents for the potential design of new active organic recyclable packaging materials. Full article

In the present study, we used a simple ultrasonic approach to develop a Cerium oxide/Graphene oxide hybrid (CeO₂/GO hybrid) nanocomposite system. Particle size analysis, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) have been used to analyze the physio-chemical characteristics of the developed nanocomposite. The synthesized hybrid system has also been examined to assess its anticancer capability against MCF-7 cell lines and normal cell lines at different sample concentrations, pH values, and incubation intervals using an antiproliferative assay test. The test results demonstrate that as sample concentration rises, the apoptotic behavior of the CeO₂/GO hybrid in the MCF-7 cell line also rises. The IC₅₀ was 62.5 µg/mL after 72 h of incubation. Cytotoxicity of cisplatin bound CeO₂/GO hybrid was also tested in MCF-7 cell lines. To identify apoptosis-associated alterations of cell membranes during the process of apoptosis, a dual acridine orange/ethidium bromide (AO/EB) fluorescence staining was carried out at three specified doses (i.e., 1000 µg/mL, 250 µg/mL, and 62.5 µg/mL of CeO₂/GO hybrid). The color variations from both live (green) and dead (red) cells were examined using fluorescence microscopy under in vitro conditions. The quantitative analysis was performed using flow cytometry to identify the cell cycle at which the maximum number of MCF-7 cells had been destroyed as a result of interaction with the developed CeO₂/GO hybrid (FACS study). According to the results of the FACS investigation, the majority of cancer cells were inhibited at the R3 (G2/M) phase. Therefore, the CeO₂/GO hybrid has successfully showed enhanced anticancer efficacy against the MCF-7 cell line at the IC50 concentration. According to the current study, the CeO₂/GO platform can be used as a therapeutic platform for breast cancer. The synergetic effects of the developed CeO₂/GO hybrid with the MCF-7 cell line are presented. Full article

In the present study, the response of the crystalline scintillator LaBr₃:Ce when excited with X-rays at tube voltages from 50 kVp to 150 kVp was investigated, for possible use in hybrid medical-imaging systems. A single crystal (10 × 10 × 10 mm³) was irradiated by X-rays within the aforementioned tube-voltage range, and the absolute efficiency (AE), as well as the detective quantum efficiency for zero spatial-frequency (DQE(0)), were measured. The energy-absorption efficiency (EAE), the quantum-detection efficiency (QDE) and the spectral compatibility with various optical photodetectors were also calculated. The results were compared with the published data for the LaCl₃:Ce, Bi₄Ge₃O₁₂ (BGO), Lu₂SiO₅:Ce (LSO), and CdWO₄ single crystals of equal dimensions. The AE values of the examined crystal were found to be higher than those of the compared crystals across the whole X-ray tube-voltage range. Regarding the EAE, LaBr₃:Ce demonstrated a comparatively better performance than the LaCl₃:Ce crystal. The emitted-light spectrum of LaBr₃:Ce was found to be compatible with various types of photocathodes and silicon photomultipliers. Moreover, the LaBr₃:Ce crystal exhibited excellent performance concerning its DQE(0). Considering these properties, the LaBr₃:Ce crystal could be considered as a radiation-detector option for hybrid medical-imaging modalities, such as PET/CT and SPECT/CT. Full article

A rare-earth trihalide scintillator, CeBr₃, in 1 cm edge cubic monocrystal form, is examined with regard to its principal luminescence and scintillation properties, as a candidate for radiation imaging applications. This relatively new material exhibits attractive properties, including short decay time, negligible afterglow, high stopping power and emission spectrum compatible with several commercial optical sensors. In a setting typical for X-ray radiology (medical X-ray tube, spectra in the range 50–140 kVp, human chest equivalent filtering), the crystal’s light energy flux, absolute efficiency (AE) and X-ray luminescence efficiency (XLE) were determined. Light energy flux results are superior in comparison to other four materials broadly used in modern medical imaging (slope of the linear no-threshold fit was 29.5). The AE is superior from 90 kVp onwards and reaches a value of 29.5 EU at 140 kVp. The same is true for the XLE that, following a flat response, reaches 9 × 10⁻³ at 90 kVp. Moreover, the spectral matching factors and the respective effective efficiencies (EE) are calculated for a variety of optical sensors. The material exhibits full compatibility with all the flat-panel arrays and most of the photocathodes and Si PMs considered in this work, a factor that proves its suitability for use in state-of-the-art medical imaging applications, such as CT detectors and planar arrays for projection imaging. Full article

Due to its excellent physicochemical properties, cerium oxide (CeO₂) has attracted much attention in recent years. CeO₂ nanomaterials (nanoceria) are widely being used, which has resulted in them getting released to the environment, and exposure to humans (mostly via inhalation) is a major concern. In the present study, CeO₂ nanoparticles were synthesized by hydroxide-mediated method and were further characterized by Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction Spectroscopy (XRD). Human lung epithelial (Beas-2B) cells were used to assess the cytotoxicity and biocompatibility activity of CeO₂ nanoparticles. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and Live/Dead assays were performed to determine the cytotoxicity and biocompatibility of CeO₂ nanoparticles. Generation of reactive oxygen species (ROS) by cerium oxide nanoparticles was assessed by ROS assay. MTT assay and Live/Dead assays showed no significant induction of cell death even at higher concentrations (100 μg per 100 μL) upon exposure to Beas-2B cells. ROS assay revealed that CeO₂ nanoparticles did not induce ROS that contribute to the oxidative stress and inflammation leading to various disease conditions. Thus, CeO₂ nanoparticles could be used in various applications including biosensors, cancer therapy, catalytic converters, sunscreen, and drug delivery. Full article

Background: The main goal of our study was to explore the wound-healing property of a novel cerium-containing N-acethyl-6-aminohexanoate acid compound and determine key molecular targets of the compound mode of action in diabetic animals. Methods: Cerium N-acetyl-6-aminohexanoate (laboratory name LHT-8-17) as a 10 mg/mL aquatic spray was used as wound experimental topical therapy. LHT-8-17 toxicity was assessed in human skin epidermal cell culture using (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. A linear wound was reproduced in 18 outbred white rats with streptozotocin-induced (60 mg/kg i.p.) diabetes; planar cutaneous defect was modelled in 60 C57Bl₆ mice with streptozotocin-induced (200 mg/kg i.p.) diabetes and 90 diabetic db/db mice. Firmness of the forming scar was assessed mechanically. Skin defect covering was histologically evaluated on days 5, 10, 15, and 20. Tissue TNF-α, IL-1β and IL-10 levels were determined by quantitative ELISA. Oxidative stress activity was detected by Fe-induced chemiluminescence. Ki-67 expression and CD34 cell positivity were assessed using immunohistochemistry. FGFR3 gene expression was detected by real-time PCR. LHT-8-17 anti-microbial potency was assessed in wound tissues contaminated by MRSA. Results: LHT-8-17 4 mg twice daily accelerated linear and planar wound healing in animals with type 1 and type 2 diabetes. The formulated topical application depressed tissue TNF-α, IL-1β, and oxidative reaction activity along with sustaining both the IL-10 concentration and antioxidant capacity. LHT-8-17 induced Ki-67 positivity of fibroblasts and pro-keratinocytes, upregulated FGFR3 gene expression, and increased tissue vascularization. The formulation possessed anti-microbial properties. Conclusions: The obtained results allow us to consider the formulation as a promising pharmacological agent for diabetic wound topical treatment. Full article

(1) Background: a cell evaluation focused to verify the self-regenerative antioxidant activity is performed on cerium doped bioactive glasses. (2) Methods: the glasses based on 45S5 Bioglass^®, are doped with 1.2 mol%, 3.6 mol% and 5.3 mol% of CeO₂ and possess a polyhedral shape (~500 µm²). Glasses with this composition inhibit oxidative stress by mimicking catalase enzyme (CAT) and superoxide dismutase (SOD) activities; moreover, our previous cytocompatibility tests (neutral red (NR), 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Bromo-2-deoxyUridine (BrdU)) reveal that the presence of cerium promotes the absorption and vitality of the cells. The same cytocompatibility tests were performed and repeated, in two different periods (named first and second use), separated from each other by four months. (3) Results: in the first and second use, NR tests indicate that the presence of cerium promotes once again cell uptake and viability, especially after 72 h. A decrease in cell proliferation it is observed after MTT and BrdU tests only in the second use. These findings are supported by statistically significant results (4) Conclusions: these glasses show enhanced proliferation, both in the short and in the long term, and for the first time such large dimensions are studied for this kind of study. A future prospective is the implantation of these bioactive glasses as bone substitute in animal models. Full article

Humans are typically exposed to environmental contaminants’ mixtures that result in different toxicity than exposure to the individual counterparts. Yet, the toxicology of chemical mixtures has been overlooked. This work aims at assessing and comparing viability and cell cycle of A549 cells after exposure to single and binary mixtures of: titanium dioxide nanoparticles (TiO₂NP) 0.75–75 mg/L; cerium oxide nanoparticles (CeO₂NP) 0.75–10 μg/L; arsenic (As) 0.75–2.5 mg/L; and mercury (Hg) 5–100 mg/L. Viability was assessed through water-soluble tetrazolium (WST-1) and thiazolyl blue tetrazolium bromide (MTT) (24 h exposure) and clonogenic (seven-day exposure) assays. Cell cycle alterations were explored by flow cytometry. Viability was affected in a dose- and time-dependent manner. Prolonged exposure caused inhibition of cell proliferation even at low concentrations. Cell-cycle progression was affected by TiO₂NP 75 mg/L, and As 0.75 and 2.5 μg/L, increasing the cell proportion at G0/G1 phase. Combined exposure of TiO₂NP or CeO₂NP mitigated As adverse effects, increasing the cell surviving factor, but cell cycle alterations were still observed. Only CeO₂NP co-exposure reduced Hg toxicity, translated in a decrease of cells in Sub-G1. Toxicity was diminished for both NPs co-exposure compared to its toxicity alone, but a marked toxicity for the highest concentrations was observed for longer exposures. These findings prove that joint toxicity of contaminants must not be disregarded. Full article

The synthesis method of metal–organic frameworks (MOFs) has an important impact on their properties, including their performance in catalytic reactions. In this work we report on how the performance of [Cu₃(TMA)₂(H₂O)₃]_n (HKUST-1) and Ce@HKUST-1 in the reaction of CO oxidation depends on the synthesis method of HKUST-1 and the way the cerium active phase is introduced to it. The HKUST-1 is synthesised in two ways: via the conventional solvothermal method and in the presence of a cationic surfactant (hexadecyltrimethylammonium bromide (CTAB)). Obtained MOFs are used as supports for cerium oxide, which is deposited on their surfaces by applying wet and incipient wetness impregnation methods. To determine textural properties, structure, morphology, and thermal stability, the HKUST-1 supports and Ce@HKUST-1 catalysts are characterised using X-ray diffraction (XRD), N₂ sorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). It is proven that the synthesis method of HKUST-1 has a significant impact on its morphology, surface area, and thermal stability. The synthesis method also influences the dispersion and the morphology of the deposited cerium oxide. Last but not least, the synthesis method affects the catalytic activity of the obtained material. Full article