Search Results (162)

This study presents a headset-type biofluorometric gas sensor incorporating a CMOS camera for continuous, non-invasive monitoring of transcutaneous ethanol from the ear canal. The sensor employs alcohol dehydrogenase (ADH) to catalyze the NAD⁺-to-NADH conversion during ethanol oxidation, enabling quantitative measurement through NADH fluorescence detection (λ_ex = 340 nm, λ_em = 490 nm). The integrated system comprises a wireless CMOS camera, an ADH-immobilized cotton mesh enzyme membrane, UV-LED excitation source, optical bandpass filters, and a dual convex lens assembly housed in a 3D-printed headset powered by a lithium battery. Key improvements include a 3.5-fold enhancement in fluorescence collection efficiency achieved through optimized dual convex lens configuration. Systematic screening of seven cotton mesh materials identified Iwatsuki cotton mesh as the optimal enzyme immobilization substrate, exhibiting minimal autofluorescence and 14.2-fold higher water retention capacity compared to H-PTFE membranes. The glutaraldehyde-crosslinked ADH-immobilized cotton mesh maintained enzymatic activity for over 45 min with a 10-fold improvement in signal-to-noise ratio. The system demonstrated a dynamic detection range spanning 10 ppb to 10 ppm for gaseous ethanol and exhibited high selectivity against interfering volatile organic compounds in skin gas, including methanol, acetaldehyde, formaldehyde, and acetone. Human experiments validated the system’s practical performance. Following alcohol consumption, subjects wore the device for 50 min while real-time fluorescence monitoring captured dynamic ethanol concentration changes in the ear canal. The dose-dependent fluorescence response—approximately 2-fold higher at 0.4 g/kg versus 0.04 g/kg alcohol intake—correlated well with calibration data. This headset-type biofluorometric sensor enables unrestrained continuous monitoring of ear canal ethanol, providing a novel wearable platform for alcohol metabolism assessment with potential applications in health monitoring and clinical research. Full article

Yeasts play a vital role in food fermentation processes, where their viability, stress tolerance, and metabolic performance directly influence product quality and process efficiency. Controlling and modulating yeast behavior represents a challenge in the food industry, particularly in non-thermal processing contexts. Ultraviolet (UV) technology has traditionally been applied as a microbial control tool; however, yeast response mechanisms to UV irradiation extend beyond simple inactivation. Depending on wavelength, dose, and treatment conditions, UV exposure can lead to complete inactivation, partial reduction in viability, or induce stable phenotypic changes associated with cellular stress responses and Deoxyribonucleic Acid (DNA) damage processing. This review examines current knowledge on yeast–UV interactions across different food matrices, highlighting how UV treatments influence yeast physiology and functionality. In addition, recent studies suggest that UV-induced genetic alterations, when properly controlled, may contribute to yeast diversification and functional modulation without the use of genetically modified organisms. The review discusses technological opportunities, practical limitations, and future research needs, emphasizing the dual role of UV technology as a tool for yeast control and as a potential driver of functional modulation. Full article

Addressing the governance dilemmas of urban vacant land (UVL) has become a major challenge in the process of global urban sustainable development. Taking Chongqing as a case study area, this paper employs Kernel Density Analysis, Bivariate Spatial Autocorrelation, and the PLUS model to explore the quantitative characteristics and spatial distribution patterns of UVL. Three scenarios—the Baseline Development Scenario, Incremental Development Scenario, and Stock Development Scenario—are constructed to simulate the evolutionary trends of UVL and investigate the regulatory effects of different urban development models. The results are as follows: (1) From 2021 to 2025, the scale of UVL shows an expanding trend. The number of UVL plots increased from 1393 to 2308, and the total area rose from 5127.73 hectares to 11,842.43 hectares, with its proportion in the built-up area increasing from 7.37% to 16.98%. (2) The spatial scope of UVL continued to expand, and the agglomeration correlation between different land types was enhanced. The spatial distribution pattern of UVL was significantly influenced by policy factors. (3) Scenario simulations show that the growth rate of UVL in 2030 is ranked as follows: Incremental Development Scenario (95.93%) > Baseline Development Scenario (69.52%) > Stock Development Scenario (43.12%). The stock development model can effectively resolve the urban contradiction between “development and protection” and represents the optimal path for future urban development. This study has clarified the evolutionary patterns of urban vacant land and their compatibility with urban development models, providing a reference for optimising vacant land management and sustainable development in similar cities. However, certain limitations exist in data acquisition and the scope of the research. Full article

The photocatalytic degradation of the pharmaceutical compound nadolol over TiO₂ under UV-LED irradiation was investigated, with particular emphasis on the inhibitory effects of common low-molecular-weight organic acids. Due to its aromatic (tetralin-like) motif and multiple heteroatom-containing functional groups, nadolol serves as a representative model for aromatic micropollutants whose fate can be governed by surface competition and noncovalent interactions. While TiO₂ showed high photocatalytic activity in ultrapure water, achieving complete nadolol degradation within 120 min, the presence of citric, oxalic, and acetic acids markedly reduced the degradation efficiency by approximately 72%, 62%, and 29%, respectively. Experimental results demonstrated that this inhibition could not be attributed solely to pH changes, indicating the contribution of additional molecular-level effects. To elucidate the underlying mechanism, molecular and periodic density functional theory (DFT) calculations were performed. The computational analysis revealed strong interactions between nadolol, organic acids, and the TiO₂ surface, leading to competitive adsorption and partial blocking of photocatalytically active sites. These results provide mechanistic insight into the role of natural organic acids in TiO₂-based photocatalytic systems and highlight the importance of considering real-water matrix components when designing efficient and sustainable photocatalytic water treatment processes. Full article

Multiband imaging (MBI) is a non-invasive, portable digital technique that has become increasingly widespread in the technical study and condition assessment of paintings, owing to its affordability and ease of use. This paper presents an experimental study aimed at optimising MBI at the microscopic scale—referred to as micro-multiband imaging (µMBI)—with the particular aim of expanding its diagnostic capabilities. A range of µMBI techniques was used on custom-made mock-ups made up of pigments selected for their spectral responses, and representative of traditional artistic materials. The techniques used included microphotography of polarised and unpolarised visible light (µVIS), raking light microphotography (µRL), transmitted light microphotography (µTL), ultraviolet-induced visible luminescence microphotography (µUVL), near-infrared microphotography (µIR), near-infrared micro-trans-irradiation (µIRT), and near-infrared false-colour microphotography (µIRFC). The results obtained through µMBI were compared with those from standard MBI methods, allowing for a critical discussion of the strengths and limitations of this emerging approach. Results evidence that µMBI provides high-resolution, spatially specific insights into materials and painting techniques, offering a more detailed understanding at the microscale of how a painting was executed. It also enables the assessment of deterioration processes (e.g., cracking, delamination, and metal soap formation), contributing to a deeper comprehension of the origin and progression of failure phenomena and supporting the development of more informed, preventive conservation strategies. Full article

Background/Objectives: Environmental contamination of dental surfaces is a major vector for cross-infection. Ultraviolet-C (UVC) irradiation provides rapid, chemical-free decontamination; however, depending on wavelength and ventilation conditions, ozone generation may occur. This study evaluated the germicidal efficacy of UVC on three high-touch surfaces: a wooden work table, a stainless-steel consumables table, and a dental unit table. Methods: Surfaces were sampled at baseline, after 5 min (27 mJ/cm²), and after 10 min (54 mJ/cm²) of UVC exposure at 90 µW/cm². Colony-forming units (CFU/cm²) were enumerated using Mueller–Hinton agar. Results: UVC achieved >99% reduction after 5 min and complete elimination after 10 min. Material properties (porosity, reflectivity, and grooves), along with quantified parameters like surface roughness (Ra) and contact angle, influenced minor differences in decontamination. Conclusions: Used with appropriate safety protocols, short-duration UVC irradiation effectively decontaminates dental surfaces and can complement chemical disinfection. Future studies must incorporate artificially soiled surfaces, biofilms, and emerging far-UVC/UV-LED technologies. Full article

Green organic coatings are developed to be deposited on and protect metallic cultural heritage artefacts from environmental degradation. This research work is carried out through a comparative study of under-development green organic and commercial coatings for indoor and outdoor applications against an artificial ageing environment. Non-destructive techniques, such as Colorimetry, Glossimetry, Eddy-current thickness measurements, and SEM-EDS investigation, are employed to assess the studied bronze substrate-coating mock-up systems’ behavior. The results showed some correlations among the studied parameters, such as the thickness–colour (namely ΔΕ parameter) relationship, while comparative conclusions provide consultant suggestions for cultural heritage conservation applications. Full article

Packaging materials made from polypropylene (PP) can be used to protect cultural heritage objects from damage ensuring their long-life preservation. This research work concerns the assessment of recycled polypropylene hollow chamber sheets as potential packaging materials for archival collections and cultural heritage objects. It was carried out through a multidisciplinary diagnostic methodology combining mechanical methods, non-destructive imaging techniques in visible light (VIS), and ultraviolet-induced visible luminescence (UVL), as well as handheld digital microscopy, colorimetry, glossimetry, and SEM microanalysis. The results showed that the condition and mechanical performance of the specimens are affected by the ageing process. Full article

Ultraviolet (UV) disinfection is a powerful method for inactivating viruses. However, comparative wavelength-dependent sensitivities among human viruses and bacteriophages remain poorly characterized. Here, we evaluated the virucidal efficiencies of UV-light emitting diode (UV-LED) against multiple coliphages (MS2, Qβ, PhiX174, and T1) and mammalian viruses, including respiratory syncytial virus (RSV) and human metapneumovirus (HMPV). We used a standardized irradiation system equipped with interchangeable UV-LED modules (250–365 nm), a low-pressure mercury lamp (254 nm), and a filtered krypton-chloride excimer lamp (222 nm). All coliphages exhibited wavelength-dependent inactivation with maximal efficiency at 263–270 nm, closely matching the action spectra of RSV and HMPV (r > 0.94, p < 0.001). However, their absolute UV sensitivities were markedly lower: under 254–281 nm irradiation. RSV and HMPV were approximately 21 and 12 times more sensitive than MS2, respectively. In contrast, far-UVC (222 nm) irradiation reduced these differences, indicating simultaneous damage to viral genomes and structural proteins. These results demonstrated that coliphages and human viruses exhibit similar wavelength-dependent sensitivity to UV-LED irradiation but differ in their absolute susceptibility. Therefore, while coliphages can be conservative surrogates for evaluating UV-LED virucidal performance, their applicability to far-UVC assessments should be interpreted with caution. Full article

Ultraviolet-A light-emitting diode (UVA-LED) irradiation is an emerging technology for biofortifying plants with enhanced nutraceuticals. This study firstly investigated effects of various doses (0-control, 16, 32, 48 J/cm²) on Chinese cabbage microgreens (CCM) quality, identifying 32 J/cm² as the suitable dose for improving total antioxidant capacity (TAC) of CCM. Based on this dosage, the following two irradiation patterns were compared: single irradiation (SI, single pulse of 32 J/cm²) and fractionated irradiation (FI; four pulses of 8 J/cm² each). Both FI and SI significantly enhanced CCM quality, though through distinct mechanisms. FI effectively promoted accumulation of biomass and vitamin C, with increases by 9.25% and 13.20%, respectively. Meanwhile, SI markedly enhanced 20.90% higher TAC than FI. This was achieved by elevating enzymatic (7.71% superoxide dismutase-SOD, 9.03% peroxidase-POD, 40% catalase-CAT, and 52.17% ascorbate peroxidase-APX) and non-enzymatic (18.89% total phenolics-TPC, 10.04% total flavonoids-TF, and 18.99% carotenoids) antioxidants. Additionally, both FI and SI significantly reduced the nitrate content. To our knowledge, this is the first study to demonstrate the effect of UVA-LED irradiation pattern on microgreens quality. These findings provide basic information for UVA-LED application in indoor agriculture and the food industry, emphasizing the importance of strategically selecting irradiation patterns to achieve specific production goals. Full article

This study establishes a detection method based on image recognition to interpret and quantitatively analyze fluorescent rapid test kits for influenza. The method operates in a dark chamber equipped with a UV-LED, where the fluorescence of the test kit is excited by the UV-LED and subsequently captured using a camera module. The captured images are processed by segmenting the regions of interest (ROI), converting them to grayscale images, and analyzing the grayscale value distributions to identify the control (C) and test (T) line regions. By comparing the values of the C and T lines, the concentration is determined to achieve quantitative analysis. In the linearity validation experiments, the concentrations of influenza A (H1N1) specimens are 2, 4, 6, 8, and 10 ng/mL, achieving a coefficient of determination (R²) of 0.9923. For influenza B (Yamagata) specimens, concentrations of 6, 8, 10, 12.5, and 25 ng/mL resulted in an R² of 0.9878. The established method enables the detection of both influenza A (H1N1) and influenza B (Yamagata), replacing visual qualitative interpretation with quantitative analysis. Currently, the detection method developed in this paper is designed for use exclusively in a dark chamber and is specifically applied to fluorescent rapid tests. It cannot be directly used with conventional colloidal gold-based rapid test reagents. In the future, the proposed detection approach could be integrated with neural networks to enable its application to non-fluorescent rapid test interpretation and to operate beyond the dark chamber environment, for example by utilizing smartphone imaging for result interpretation under normal lighting conditions. Full article

Ultraviolet-light emitting diodes (UV-LEDs) offer several advantages over conventional mercury-based UV lamps, including wavelength selectivity, compact size, design flexibility, instant on/off, power output adjustment, and mercury-free operation. These features position UV-LEDs as ideal candidates for point-of-use (POU) water disinfection systems, particularly in decentralized or resource-limited environments. In this study, we evaluated the microbial inactivation performance and energy efficiency of a bench-scale flow-through UV-LED POU system using indigenous heterotrophic plate count (HPC) bacteria, E. coli, and MS2 bacteriophage. The system was tested under various flow rates (1–4 L/min) and wavelength configurations (265 nm, 278 nm, and dual-wavelength combinations). MS2 bacteriophage was further used in collimated beam testing to validate UV-fluence-response curves and to estimate delivered doses in the flow-through POU device. HPC inactivation was enhanced under dual-wavelength conditions, suggesting wavelength-specific synergy, while E. coli showed high susceptibility across all wavelength configurations, achieving >2-log inactivation at significantly reduced UV-LED power (1/6 of that required for HPC) even at 4 L/min. Specific energy consumption analysis showed energy demands as low as 0.032–0.053 kWh/m³ for achieving 4-log inactivation of E. coli, with an estimated annual operating cost for UV-LED irradiation below $1.70. These findings demonstrate the potential of UV-LED-based POU devices as safe, energy-efficient, and cost-effective technologies for decentralized water treatment. Full article

The photocatalytic efficiency of TiO₂ was significantly enhanced by coupling with WO₃ to form a TiO₂/WO₃ heterostructure, designed to operate effectively under UV-LED irradiation. The nanocomposites were synthesized via a hydrothermal route, and their activity was evaluated through the degradation of the pharmaceutical pollutant venlafaxine. Contaminants are rarely addressed in photocatalytic studies. Unlike a simple physical mixture of commercial TiO₂ and WO₃ powders, the hydrothermally synthesized TiO₂/WO₃ photocatalyst exhibited superior efficiency, attributable to its nanoscale dimensions achieved via the hydrothermal route, which promoted improved charge carrier separation, enhanced surface homogeneity, and the formation of an effective heterojunction interface. An optimization study varying the WO₃ content (5, 10, 20, and 30 wt.%) within the TiO₂ revealed that the 10 wt.% WO₃ composition achieved the highest performance, with ~52% venlafaxine degradation within 60 min. SEM, TEM, FTIR, Raman spectroscopy, XRD, and UV-Vis DRS revealed the successful incorporation of WO3 into the TiO₂ matrix, confirming phase purity and composition-dependent structural evolution of the nanocomposite, and evidencing extended light absorption and superior charge-transfer properties. Importantly, the optimized photocatalyst thin film retained excellent stability and reusability, maintaining high degradation efficiency over three consecutive cycles with negligible activity loss, which avoids slurry separation. These findings establish hydrothermally synthesized TiO₂/10%WO₃ thin film heterostructures as effective and sustainable photocatalytic platforms for the removal of pharmaceutical pollutants in wastewater under UV-LED irradiation. Full article

This study investigates the influence of photoinitiating systems on the degree of methacrylate group conversion and the rate of polymerization in UV/LED-curable nail gel formulations. Camphorquinone and Eosin Y, commonly used in medical and dental applications, were evaluated in bimolecular systems with onium and iodonium salts, thiols, and amines as co-initiators. Real-time FT-IR spectroscopy was employed to monitor polymerization under dual-LED irradiation (365 nm and 405 nm). The results demonstrate that the tested systems, inspired by photocurable medical products, exhibit significant potential for application in highly pigmented nail gels, achieving efficient curing with low residual monomer content. Full article

Religious panel paintings (icons) play a pivotal role in the rituals of the Eastern Orthodox Christian Church. However, their continuous use often results in physical degradation, prompting remedial interventions. Quite commonly, alterations were treated by simply applying new paint layers directly over the decayed original, while in some cases, old icons were overpainted merely as a means to renovate and modernize them. Therefore, numerous overpainted icons are currently housed in churches, museums, and private collections across Greece. This study focuses on the investigation of a post-Byzantine icon of Christ Pantokrator, which displays extensive overpainting while retaining a few visible fragments of the original composition. The objective was to assess the extent and condition of preservation of the original artwork, to identify materials and techniques used both in the initial painting and in subsequent restoration phases, and to distinguish between those phases. To achieve these aims, a fully non-invasive diagnostic methodology was implemented, including visible light photography, ultraviolet radiation imaging (UVR/UVL), hyperspectral imaging (MuSIS HS), infrared reflectography (IRRef), X-ray radiography, and macroscopic X-ray fluorescence scanning (MA-XRF). The findings confirm that the original painting remains substantially preserved and is of high artistic quality. Moreover, analysis revealed at least two distinct phases of overpainting, likely dating from the 20th century, while the results suggest that the original artwork probably dates to the first half of the 18th century. The study highlights the need to use complementary techniques in order to non-invasively assess complex artifacts like overpainted icons and offers valuable insights into historical restoration practices providing foundation for future conservation planning. Full article