Search Results (1,209)

CuO thin layers were synthesized using the sol–gel method and deposited onto glass substrates through the dip-coating technique. The impact of annealing temperatures on the structural, optical, and electrical characteristics of the developed CuO thin layers was comprehensively assessed through X-ray diffraction, UV–visible spectrophotometry, and four-point techniques, respectively. X-ray diffraction analysis revealed the formation of CuO thin layers with a distinctive monoclinic tenorite phase structure. The UV–visible spectrophotometer results demonstrated a decrease in transmittance from approximately 30% to about 7% as the annealing temperature increased from 200 °C to 400 °C. The semiconducting properties exhibited temperature-dependent variations, with the band gap narrowing from 1.70 to 1.48 eV as the temperature increased from 200 to 400 °C. Additionally, the electrical conductivity of the CuO layers exhibited a significant increase from 48 to 61 S.m⁻¹ over the same temperature range. Collectively, the findings suggest that an annealing temperature of 400 °C is optimal for achieving well-crystallized CuO layers with desirable characteristics, including high absorbance, low transmittance, a reduced energy band gap, and enhanced electrical conductivity. These results underscore our ability to manipulate CuO properties, offering insights for tailoring them to meet specific requirements, particularly in the context of gas sensor applications. Full article

Background: The aim of this study was to evaluate the whitening efficacy and long-term stability of different in-office bleaching agents containing high concentrations of hydrogen peroxide (HP). Methods: Records of 50 patients who underwent in-office bleaching treatment at the Department of Restorative Dentistry, Ege University, were retrospectively analyzed. Five bleaching agents were evaluated: Opalescence (40%HP), FGM Whiteness HP (35%HP), FGM Whiteness HP Blue (35%HP), Biowhiten (40%HP) and Powerbright (35%HP). Color measurements were obtained using a spectrophotometer (VITA Easyshade V, VITA Zahnfabrik, Bad Säckingen, Germany) and standardized intraoral photographs at baseline, immediately after treatment, at 1 week, 6 months, 12 months, and 18 months. Color change (ΔE₀₀) was calculated using the CIEDE2000 formula, and shade differences were assessed using ΔSGU values. Statistical analyses were performed using repeated-measures ANOVA and Kruskal–Wallis tests, followed by post hoc comparisons where appropriate (p < 0.05). Results: Baseline age distribution, initial color parameters, and patient-related behavioral factors were comparable among the groups, with no statistically significant differences observed. All bleaching agents resulted in significant color improvement at the 1-week evaluation (ΔE₀₀ range: 3.67–6.34; p < 0.05), exceeding clinically acceptable thresholds. At 6 months, slight, non-significant reductions in ΔE₀₀ values were observed in the Powerbright, FGM Whiteness HP Blue, and FGM Whiteness HP groups (p > 0.05). At 18 months, ΔE₀₀ values remained within a clinically acceptable range (3.56–4.74), with no significant color regression in most groups (p > 0.05), except for a significant decrease in the FGM Whiteness HP group (p < 0.05). Conclusions: High-concentration (35–40%) in-office bleaching agents demonstrated effective short-term whitening and maintained clinically acceptable and stable color outcomes over 18 months. Although material-dependent differences were observed, bleaching efficacy and long-term color stability appear to be influenced by multiple factors beyond hydrogen peroxide concentration alone. These findings support the clinical reliability of in-office bleaching procedures and highlight the importance of long-term follow-up. Full article

The pharmaceutical industry is a major source of pollution in wastewater effluents, characterized by chemical residues that are complex and difficult to degrade. Naproxen, a commonly detected drug in sewage effluents, exceeds safe concentrations for aquifers and is highly persistent, posing significant risks to aquatic life and ecosystems. This drug is known to cause long-term side effects in humans, such as gastrointestinal ulcers and nephrosis, associated with frequent and prolonged use. Additionally, the recent pandemic has led to a marked increase in drug consumption over a short period, exacerbating environmental contamination. Titanium dioxide has been extensively used as a photocatalyst in recent decades, proving effective in reducing these emerging pollutants. In this study, TiO₂ doped with cerium was synthesized using the sol–gel method, with cerium concentrations varied at 1, 3, 5, and 10% by weight. The resulting nanocatalysts were characterized through nitrogen physisorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis diffuse reflectance spectroscopy. Photocatalytic activity was assessed using a UV-Vis spectrophotometer to monitor the degradation of the drugs. XRD analysis confirmed the crystallinity and anatase phase of TiO₂. UV-Vis diffuse reflectance spectra indicated a decrease in bandgap energy of up to 3.00 eV compared to pure TiO₂. The materials demonstrated significant degradation of naproxen (NPX) and acetaminophen (ACTP), both prepared at 30 ppm, over a 6 h reaction period. Full article

This study aimed to develop a novel fluorescent sensor based on Eu³⁺ complex-doped protein crystal (EC-PC) for the efficient detection of metal ions in blood. By meticulously controlling the crystallization and annealing conditions in the co-crystallization strategy, the crystal growth processes were optimized to obtain doped Eu³⁺ complex-co-protein crystalline (EC-PC) structures. Thus, through co-crystallization of hen egg white lysozyme (HEWL) as a model protein and Eu³⁺ complex as fluorescent center, we successfully prepared Eu³⁺ complex-doped-HEWL co-crystals (EC-HC) with excellent fluorescent properties. Further treatment with 4% glutaraldehyde cross-linking enhanced the structural stability of the co-crystals. Moreover, the characteristic of sensitive, selective quenching of EC-PC fluorescence by biologically relevant cations, such as Cu²⁺, Zn²⁺, Mg²⁺, Ca²⁺ and Fe³⁺ ions, set up a smart sensing system in blood. For example, the fluorescence intensity of the crystals at 610 nm, as measured by a UV–visible spectrophotometer, decreases dose-dependently with the concentration of copper ions, thereby validating the sensor’s high sensitivity to copper ion detection. Significantly, we also found that this hybrid protein-based sensor did not induce hemolysis, at various volume concentrations, confirming good anticoagulation in blood. This research not only provides a new perspective on the application of Eu³⁺ complex-doped protein crystals in the field of biosensing but also offers a new strategy for the detection of biologically relevant cations in blood. Future work will focus on further optimizing the sensor’s performance and exploring its potential applications in clinical sample analysis. Full article

Beryllium (Be), a critical strategic metal element, is predominantly extracted from beryl, which serves as a key mineral combining significant strategic importance with essential industrial applications. Significant debate remains, however, regarding the mineralogical characteristics and color-causing mechanisms of beryl. In this study, we integrate Electron Probe Microanalysis (EPMA), Fourier transform infrared spectrometer (FTIR), laser Raman spectrometer (LRS), X-ray diffractometer (XRD), and ultraviolet–visible spectrophotometer (UV-VIS) to elucidate the mineralogy and spectral characteristics of pegmatitic beryl from Xinjiang, Northwest China. The results indicate that the beryl mainly presents a yellowish-green color, associated with minerals such as feldspar, quartz, and garnet. The EPMA results confirm the chemical composition of the typical beryl and indicate that the Al content is lower than the theoretical value, reflecting the substitution of Al³⁺. The FTIR shows characteristic vibrations of Si-O tetrahedral groups within the range of 1400~400 cm⁻¹, along with distinct bending and stretching vibration peaks of H₂O molecules observed in the range of 1700~1500 cm⁻¹ and 3500~3800 cm⁻¹, respectively. Combined with spectral analysis, it can be determined that both Type I water and Type II H₂O are present in the samples. Raman spectroscopy reveals that the two distinct peaks of beryl are located at approximately 685 cm⁻¹ (attributed to the stretching vibration of Be-O) and 1067 cm⁻¹ (corresponding to the bending vibration of Si-O), respectively. The XRD analysis shows that the ratio of unit cell parameters c/a of the samples ranges from 0.9950 to 1.0068, and the isomorphous substitution in its structure is mainly manifested as the replacement of octahedral coordination sites by Al³⁺. The UV-VIS shows that Fe³⁺ exhibits a broad absorption band in the range of 200~300 nm, while no obvious absorption peaks are observed in the range of 300~800 nm. The above characteristics indicate that Fe³⁺ has a significant impact on the color of beryl. For green beryl samples, a portion of Fe³⁺ occupies the structural channel sites and interacts with H₂O molecules within the channels, which contributes to the yellowish hue of beryl. Our study highlights crucial data for mineralogical identification, genetic tracing, as well as efficient utilization of beryl resources. Full article

The green synthesis of nanoparticles offers a solution to control pesticide-resistant pests while minimizing environmental and health risks. Thrips tabaci is an injurious pest that attacks garlic crops and spreads the Iris yellow spot virus. The present research was performed to evaluate the synergistic effects of silver nanoparticles (AgNPs) synthesized by Teucrium polium with Spinosad against T. tabaci and assess their impact on garlic photosynthetic pigments. The characterization of the prepared nanoparticles was carried out by SEM, XRD, and Malvern zeta sizer. Antimicrobial activity was assessed using microdilution. Photosynthetic pigments were measured with a spectrophotometer after treating garlic cloves with four different concentrations of AgNPs and Spinosad mixture along with positive control (Spinosad) and negative control (tap water). Toxic bioassays were conducted under laboratory, greenhouse, and open field conditions. The results indicate all treatments, except for the 100% AgNPs, resulted in 100% second instar larvae and adult mortality after 72 h in the laboratory. In greenhouse conditions, the 50% Spinosad–50% AgNPs achieved 93.85% larvae mortality, and the 75% Spinosad–25% AgNPs achieved 100% adult mortality after a week. In open field conditions, the combination 50% Spinosad–50% AgNPs showed high efficacy, resulting in 65.97% mortality of larvae and 73.06% mortality of adults after 72 h. This study reveals that AgNPs have active pesticide properties against T. tabaci with minimal environmental and health risks. Full article

Despite advances in dental materials and digital color registration systems, esthetic matching remains a clinical challenge for both dental students and experienced professionals. A comprehensive narrative review was conducted through bibliographic searches in PubMed, Scopus, Web of Science, and PsycINFO databases from January 2015 to January 2026. The evidence was synthesized using a four-dimensional analytical framework encompassing technological, cognitive–psychological, educational, and clinical-contextual factors. Quantitative synthesis revealed substantial variability in shade matching success rates, with intraoral scanners demonstrating pass rates ranging from 31.3% to 78.2% across devices, while spectrophotometers achieved superior repeatability (ICC > 0.9) but faced interpretive barriers. Cognitive load theory explains the performance deterioration, with novices being particularly susceptible to retinal fatigue and metamerism under non-standardized lighting conditions. The proposed paradigm shift involves redefining shade selection from a purely technical task to a cognitive skill that requires deliberate perceptual calibration, structured educational protocols, and hybrid digital visual workflows. To improve esthetic predictability, educational programs need to integrate longitudinal training in color science with objective feedback mechanisms. Clinical workflows should adopt hybrid calibration-centric protocols that position technology as a verification tool, rather than a replacement for clinical judgment. Understanding the multidimensional nature of shade matching difficulty enables the development of evidence-based educational protocols and clinical workflows, ultimately improving esthetic outcomes. Full article

Blood glutathione (GSH), its oxidized form glutathione disulfide (GSSG), and especially the ratio of reduced to oxidized glutathione (GSH/GSSG) are recognized as robust biomarkers of oxidative stress. However, the broader application of these biomarkers has been limited by two major challenges: (1) the high risk of artifact formation during sample handling, which can artificially increase GSSG levels and bias redox balance measurements, and (2) the reliance on complex, instrument-intensive analytical procedures and the requirement for venous blood. We present an adaptation of the highly sensitive and easy-to-perform Tietze recycling method for microvolumes of blood. The challenge is to achieve accurate and precise measurements while avoiding artifacts, taking advantage of the high sensitivity of this enzymatic recycling analytical procedure. The method uses a simplified sample preparation protocol compatible with small blood volumes (up to 10 μL) and requires only basic laboratory equipment, such as a standard spectrophotometer or microplate reader. As this is an enzyme-based assay, we also carefully evaluate the main factors that can affect the measurements. This novel procedure provides a practical tool for monitoring GSH/GSSG as a biomarker of oxidative stress in various experimental settings by eliminating the need for trained personnel for blood sampling (it is suitable for capillary blood), minimizing discomfort for subjects, and avoiding complex procedures or instruments for analyte detection. Full article

Objective: This in vitro study aimed to compare the layer-matched color compatibility of three 3Y/4Y/5Y multilayer zirconia grades marketed in shade A2. Materials and Methods: Disc specimens (18 mm × 1.5 mm) were milled from pre-shaded multilayer zirconia blanks (Katana™ Multi-Layered Zirconia; Kuraray Noritake Dental Inc., Tokyo, Japan) in three grades: UTML (5Y), STML (4Y), and HTML (3Y). Twelve discs per grade were polished and measured on a neutral-gray background (Munsell N7) using a dental spectrophotometer (VITA Easyshade Advance 4.0; VITA Zahnfabrik, Bad Säckingen, Germany) at the incisal, middle, and cervical thirds. Color differences were calculated using CIEDE2000 (ΔE₀₀). Yttria content (wt%) was determined using EDS (JSM-7800F; JEOL Ltd., Tokyo, Japan), and phases were assessed using XRD (X’Pert PRO; Malvern Panalytical, Almelo, The Netherlands); microstructure and grain size were examined using FE-SEM after thermal etching. Statistics: A two-way mixed-design ANOVA with Bonferroni adjustment (α = 0.05) was conducted. Results: A significant incisal-to-cervical gradient was observed within each grade (p < 0.001), whereas layer-matched inter-material differences were small (all ΔE00 < 1.0), i.e., below the commonly accepted perceptibility threshold. EDS confirmed the expected stepwise decrease in Y₂O₃ from UTML to HTML, accompanied by corresponding changes in phase constitution and grain size. Conclusions: Despite compositional and microstructural differences, the three multilayer zirconia grades showed no clinically perceptible layer-matched color differences, supporting their combined use in extended rehabilitations while maintaining the natural-like color gradient across the multilayer blank. Full article

As one of the core technologies in modern national defense and security fields, infrared stealth technology aims to realize the controllable regulation of the radiation characteristics of targets in the infrared band. This paper focuses on a novel electrochromic device with a structure of WO₃/nickel mesh/Al³⁺-Zn²⁺gel electrolyte/zinc foil. The structural composition and working mechanism are systematically analyzed, and the infrared stealth regulation performance is emphatically studied. The WO₃ thin film and device structure were characterized by scanning electron microscopy (SEM). The infrared emissivity modulation and optical response properties of the device were measured using an infrared thermal imager and a UV-Vis-NIR spectrophotometer. The prepared WO₃ film exhibits a dense spherical morphology, indicating excellent uniformity and compactness. After 1000 cycles, the areal capacitance of the device remains 83.7% of its initial value, demonstrating good cycling stability. Under the voltage regulation of −0.1 V to 1.1 V, the emissivity ε of the device at the typical mid-wave infrared wavelength of 4.0 μm decreases from 0.89 (−0.1 V) to 0.67 (1.1 V), with an absolute modulation amplitude Δε of 0.22. At the typical long-wave infrared wavelength of 8.7 μm, ε decreases from 0.96 (−0.1 V) to 0.69 (1.1 V), with an absolute modulation amplitude Δε of 0.29. The electrochromic switching times for coloring and bleaching are 10.1 s and 2.44 s, respectively. According to infrared thermal imaging tests, in the temperature range of 30–40 °C, the surface temperature difference ΔT between the colored state and bleached state increases from 4.3 °C to 4.6 °C. The maximum regulation amplitude reaches 4.6 °C at 40 °C. The device achieves efficient regulation of infrared emissivity through the electrochromic effect, providing a new device design strategy for infrared stealth technology. Full article

Glass ionomer cements (GICs) are considered functionally biomimetic as they participate in ion-exchange processes that partially resemble the behavior of natural enamel and dentin, chemically bond to dental hard tissues, and release fluoride. While GICs are designed to interact with aqueous oral environments, their exposure to dietary beverages may affect their esthetic stability and water-related behavior within the oral environment. For biomimetic restorative materials to perform successfully in the oral environment, they must maintain not only bioactive properties but also esthetic stability and resistance to water-related degradation during exposure to dietary beverages. This study evaluated beverage-induced color changes, water sorption, and water solubility of six GICs following their immersion in coffee, tea, berry juice, cola, and distilled water (n = 5 per material per solution). Color measurements were recorded at baseline and after 2, 4, 6, and 8 weeks using a spectrophotometer, and color change (ΔE) values were calculated using the CIE L*a*b* system. Specimen mass was measured at baseline, after 8 weeks of immersion and then after 4 weeks of desiccation. Data were analyzed using repeated-measures Analysis of Variance (ANOVA) and Fisher’s least significant difference post hoc tests (α = 0.05). The results showed time, material, and solution significantly affected ΔE (p < 0.001). Tea produced the greatest discoloration overall, followed by coffee. ChemFil exhibited the greatest staining susceptibility, while Fuji II showed the lowest staining susceptibility. Water sorption and solubility were material- and solution-dependent. Clinically relevant discoloration of GICs was found when immersed in common beverages over time, with tea showing the strongest staining effect. These findings indicate that although GICs exhibit biomimetic characteristics through their interaction with tooth structures and aqueous environments, their long-term esthetic stability and resistance to environmental challenges should also be considered when selecting restorative materials for clinically visible areas. Full article

Copper (Cu) is a biologically important trace metal in marine environments, and its chemical speciation is strongly influenced by interactions with dissolved organic matter (DOM), which can significantly regulate its bioavailability and toxicity. A chemical speciation study of dissolved Cu by adsorptive stripping voltammetry in conjunction with the characterization of DOM by UV-Vis spectrophotometer in the coastal hypersaline waters of Kuwait Bay was carried out in this study. DOM exhibited strong Cu-binding capacity, forming thermodynamically stable Cu-DOM complexes with Log K values ranging from 11.5 ± 0.3 to 14.4 ± 0.5 in the study area. Chemical speciation parameters of Cu-DOM complexes varied with proxies for humic acid (HA) and fulvic acid (FA) concentrations, and with increasing molecular weight of the DOM. These findings suggest that both autochthonous and allochthonous organic matter play vital roles in binding dissolved Cu and controlling Cu²⁺ ion concentrations (an indicator of bioavailable Cu) in the coastal waters of the northwestern Arabian Gulf off Kuwait. Full article

Background/Objectives: The increasing use of digital manufacturing techniques in prosthodontics has raised concerns regarding the long-term esthetic performance of provisional restorations. This in vitro study aimed to compare the color stability of provisional restorations fabricated by additive (3D-printed) and subtractive (milled) manufacturing techniques after immersion in common staining beverages. Methods: Eighty polymethyl methacrylate (PMMA)-based specimens (16 × 1 mm) were fabricated and divided into two groups: additive (n = 40) and subtractive (n = 40). Each group was immersed in coffee, red wine, green tea, or cola for 60 and 120 h at 37 °C. Color measurements were recorded using a spectrophotometer in the CIE LCh* system, and color differences (ΔE₀₀) were calculated using the CIEDE2000 formula. Data were analyzed using repeated-measures analysis of variance (ANOVA) and Tukey post hoc tests (α = 0.05). Results: Additively manufactured specimens showed significantly higher color change (ΔE₀₀) values than subtractively milled specimens across all immersion media and time intervals (p < 0.05). Red wine and coffee caused the greatest discoloration, whereas cola produced the least effect. Conclusions: Within the limitations of this study, additive manufacturing resulted in lower color stability than subtractive fabrication. Subtractive PMMA materials exhibited superior optical behavior, suggesting their suitability for long-term provisionalization in esthetically demanding clinical situations. Full article

Bisphenol-A (BPA) and butylparaben (BP) are recognized as emerging contaminants due to their extensive use in plastics and personal care products, posing significant risks to ecosystems and human health. Understanding their transport behavior is vital for predicting environmental fate and designing mitigation measures. This study quantifies the diffusion coefficients of BPA and BP under infinite dilution conditions to simulate realistic environmental scenarios. Laboratory experiments employed a UV-Visible spectrophotometer to monitor concentration changes over time at four initial BP concentrations (0.0005–0.0025 M) and at temperatures between 294.85 K and 304.15 K. Experimental data show that BP concentrations at lower initial values (0.0005 M and 0.00075 M) remained constant, indicating minimal diffusion. Theoretical estimations using the Stokes–Einstein equation yielded diffusion coefficients at 299.38 K of 1.51 × 10⁻¹³ m²/s for BP and 8.47 × 10⁻¹⁴ m²/s for BPA. The Wilke–Chang equation estimated higher values: 1.21 × 10⁻¹⁰ m²/s for BP and 1.18 × 10⁻¹⁰ m²/s for BPA at the same temperature. Results confirm that temperature increases enhance diffusion, while molecular size differences cause BP to diffuse faster than BPA. The robust experimental dataset produced here supports the refinement of predictive models for contaminant mobility. These insights are critical for risk assessment and for developing targeted strategies to minimize the persistence and spread of endocrine-disrupting chemicals in aquatic and terrestrial systems. Full article

Ciprofloxacin (CIP) is an antibiotic that is widely used in humans and animals. However, the compound has been detected in animal-derived products and the environment due to its extensive use, causing serious concern for public health and environmental safety. The issue raises the urgent need to develop innovative techniques to monitor CIP. Therefore, this study aims to develop a simple and sensitive CIP sensor called the boron-doped diamond nanoparticle-modified screen-printed electrode (BDD NPs/SPE) and the nickel oxide nanoparticle-modified BDD NPs/SPE (NiO NPs/BDD NPs/SPE). NiO NPs were synthesized via green synthesis using Spatholobus littoralis Hassk. root extract as the reducing agent. The formation and characteristics of NiO NPs were then confirmed through a UV-Vis spectrophotometer, XRD, PSA, FT-IR, and XPS. The successful modification of SPE was confirmed through SEM-EDX, followed by measurements using square-wave voltammetry. The results showed that the modified SPE could detect CIP over a concentration range of 0.1–100 µM and produced a low detection limit of 0.109 µM for BDD NPs/SPE and 0.054 µM for NiO NPs/BDD NPs/SPE. The proposed method was successfully applied to the determination of CIP in commercial tablets, milk, and human urine, with a satisfactory % recovery from 95 to 100%. The current study successfully developed a simple yet highly sensitive sensor that enabled robust, reliable, and efficient detection of CIP, showing its strong potential for practical applications. Full article