Search Results (2,073)

Bactrocera dorsalis (Diptera: Tephritidae) ranks among the most serious quarantine pests threatening global fruit and crop production. Irradiation has been adopted worldwide as an eco-friendly phytosanitary treatment strategy, yet how B. dorsalis responds to irradiation is not fully understood. To investigate the transcriptional response to irradiation, third-instar B. dorsalis larvae were exposed to two X-ray doses: a sub-effective dose of 15 Gy and a phytosanitary dose of 120 Gy. Comparative transcriptomic profiling revealed a clear dose-dependent escalation in the number of differentially expressed gene (DEGs). While 15 Gy primarily disrupted basic metabolism and cuticle integrity, 120 Gy induced a systemic metabolic collapse coupled with severe genotoxic stress, activating DNA repair, lysosomal degradation, and the JAK-STAT signaling pathway. Notably, we identified nine dose-specific candidate biomarker genes that are exclusively regulated at the phytosanitary dose. These findings elucidate the molecular network mediating radiation-induced mortality and provide rapid molecular diagnostic tools for validating phytosanitary irradiation efficacy and optimizing pest management strategies. Full article

This study provides an in-depth investigation of the influence of calcium carbonate (CaCO₃) filler on the mechanical performance and aging resistance of polyvinyl chloride (PVC)-based composites. PVC/CaCO₃ composites containing 2.5, 5, and 7.5 wt% of CaCO₃ were subjected to accelerated aging under combined ultraviolet (UV) irradiation and thermal stress for up to 1248 h. The key mechanical properties of specimens —tensile strength and elongation at break—were measured before and after aging. Changes in surface morphology, coloration, hydrophobicity, and chemical composition were characterized using scanning electron microscopy (SEM-EDS), X-ray spectroscopy, atomic force microscopy (AFM), contact angle measurements, and carbonyl index calculation to quantify relationships between the structural and physical properties of the specimens and aging conditions. The results reveal a significant correlation between filler content and the mechanical behavior of aged specimens, highlighting the potential of CaCO₃ reinforcement not only to improve the retention of mechanical properties but also to increase the service life of PVC-based insulation compounds. Full article

This study addresses the urgent issue of nitrate-contaminated water by investigating Ni-Pt and Co-Pt catalysts supported on TiO₂, with the aim of improving both photocatalytic efficiency and reaction selectivity. The influence of adding non-noble metal co-catalysts to TiO₂, in addition to Pt, was explored. The synthesized samples were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H₂-TPR), diffuse reflectance UV–Vis spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS). The assessment of catalytic performance was conducted during the catalytic hydrogenation of nitrate, followed by an evaluation of the photocatalytic performance achieved when the aqueous nitrate solution was irradiated with UV light. The focus is on assessing the synergistic effects of the catalysts supported on TiO₂ in nitrate reduction, as well as their selectivity towards benign reaction products during the photocatalytic process, in contrast to the reactions occurring in the absence of light. Despite the selectivity for nitrite being preserved, the photocatalytic experiments indicated that the selectivity for N₂ reached around 68%, which is about 1.5 times higher than the values observed during the dark catalytic reaction. In contrast, the selectivity for ammonium saw a notable reduction. The findings were discussed in relation to the characteristics of the synthesized materials. Full article

Two tri-carbonyl complexes, [Mn(CO)₃(5cpa)Br] (1) and [Re(CO)₃(5cqn)(OCH₃)] (2), were synthesized, where 5cpa is 5-Cl-2-picolinic acid and 5cqn is 5-Cl-8-Hydroxyquinoline. Their structures were determined using X-ray diffraction techniques. The electronic absorption and IR spectra of the complexes were experimentally measured and theoretically assigned through density functional theory (DFT) calculations. The photo-induced CO release was verified using time-resolved infrared spectroscopy, and the transfer of CO to hemoglobin (Hb) was monitored by UV-vis spectroscopy. The rate of CO release and transfer from Mn complex 1 is significantly faster than that from Re complex 2. Complex 2 exhibits higher cytotoxicity against HeLa cells than complex 1, with IC₅₀ values of 40.1 μM and 10.6 μM for 1 and 2, respectively, which decrease to 16.2 μM and 4.9 μM after photo irradiation. Moreover, 1 exhibited a stronger binding constant (K_b) with human serum albumin (HSA) than 2, with values of 1.6 × 10⁶ and 7.0 × 10⁵ M⁻¹, respectively. The structures of HSA complex adducts revealed that both the resulting [Mn(CO)₃(5cpa)]⁻ and [Re(CO)₃(5cqn)]⁻ group coordinate with the N atom of His146, while four additional dissociated Mn-CO groups were observed to bind to HSA for complex 1. This study provides insights into the stability, possible metabolic pathways, and potential applications of these carbonyl complexes. Full article

Three new isomeric pyridone fluorenone hydrazone-based boron complexes, 3-BrN to 5-BrN, with bromination at the 3-, 4-, or 5-position of the pyridone ring and their corresponding σ-platinum complexes trans-Pt(PEt₃)₂(n-N)X (n = 3, 4, or 5; X = Cl, Br, I) resulting from oxidative addition of the aryl-Br bond of n-BrN to Pt(PEt₃)₂ and, for X = Cl, I, subsequent substitution of the halogenide ligand, were synthesized and characterized by NMR, UV–Vis absorption, and photoluminescence spectroscopy. The molecular structures of dyes 3-BrN to 5-BrN and of seven complexes, including the cis-isomer of the bromo complex resulting from 3-BrN, were established by single X-ray diffraction. The nearly orthogonal orientation of the Pt coordination plane with respect to the plane of the dye ligand limits intermolecular π-stacking interactions in the crystalline state while giving rise to extensive C-H···halogen and C-H···π interactions, resulting in intricate packing patterns. Electronic absorption spectra of dyes 3-BrN to 5-BrN show a prominent HOMO-LUMO absorption band at ca. 520 nm, which is red-shifted and intensifies on platination. All compounds are dual fluorescence and phosphorescence emitters in the range of 520 to 670 nm, or at ca. 1000 nm, both at room temperature and at 77 K. The population of an excited triplet state and their photostability even towards continuous light irradiation renders these compounds efficient sensitizers for singlet oxygen generation and catalysts for the photo-oxidation of triphenylphosphine. Full article

In this study, zirconia specimens were subjected to Al₂O₃ airborne-particle abrasion and Er laser irradiation to investigate their effects on surface characteristics. The treated and untreated zirconia surfaces were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), qualitative elemental analysis by laser-induced breakdown spectroscopy (LIBS), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, XRD analysis, and power spectral density (PSD) analysis. The Er laser-treated group showed the highest mean surface roughness (Sa: 7.763 ± 2.449 µm), compared with the Al₂O₃-treated group (3.640 ± 2.164 μm); however, the differences in Sa among the experimental groups were not statistically significant (Kruskal–Wallis, p = 0.095). Likewise, no statistically significant differences were observed for Sz (one-way ANOVA, p = 0.567). SEM, AFM, and PSD analyses provided complementary information on the morphological and spatial characteristics of the surfaces produced by the different treatments. Under the experimental conditions evaluated, Er laser irradiation produced distinct surface topographic features and a descriptive trend toward higher mean Sa values, but statistical superiority over Al₂O₃ airborne-particle abrasion or the untreated control was not demonstrated. Further studies are required to determine whether these surface modifications translate into functional or clinical benefits. Full article

The photocatalytic degradation of the 2,5-diphenyl-1,3-oxazole (PPO) and 2-(4-biphenyl)-5-phenyl-1,3,4-oxadiazole (PBD), which are laser dyes and scintillator compounds, was investigated under ultraviolet (UV) light irradiation using pure and rare-earth (Sm³⁺, Eu³⁺, and Gd³⁺)-modified zinc oxide (ZnO) hierarchical flower-like microstructures. The synthesized photocatalysts (powder) were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD), confirming the formation of flower-like ZnO structures and successful modification by the oxides Sm₂O₃, Eu₂O₃, and Gd₂O₃. Residual concentrations of Zn²⁺, Gd³⁺, Sm³⁺, and Eu³⁺ in the treated aqueous solutions were determined by ICP-MS to evaluate catalyst stability, while chemical oxygen demand (COD) analysis was used to assess mineralization efficiency. For both PPO and PBD, the photocatalytic activity followed the order ZnO < ZnO/Gd₂O₃ < ZnO/Sm₂O₃ < ZnO/Eu₂O₃, which can be attributed to the enhanced charge separation and reduced electron–hole recombination caused by rare-earth ions, with Eu³⁺ providing the most effective electron trapping. PPO showed faster degradation than PBD, mainly due to the structure of the PBD molecule, which is more rigid and conjugated, owing to its higher resistance to oxidative degradation. Full article

This study addresses the need for dark-current control and stable current response in planar high-purity germanium (HPGe) detectors for low-energy X-ray detection. A device fabrication strategy based on the coupled optimization of near-surface treatment, N/P junction formation, and guard-ring electrode design is proposed. Unlike previous studies that mainly focused on contact-layer fabrication, segmented electrode structures, low-noise readout, or response simulation, this work investigates low-damage near-surface construction, N-type and P-type contact-layer formation, and edge-related leakage-current regulation as an interconnected processing route. The relationship among the near-surface state, junction quality, electrode configuration, and edge-related leakage current is emphasized. Chemical mechanical polishing (CMP) reduced the surface roughness Sa of the HPGe crystal to 6.68 nm, providing a low-damage near-surface foundation for subsequent junction fabrication. On this basis, the optimized Li thermal diffusion process, namely 0.5 Å s⁻¹, 325 °C, and 5 min, formed an N-type contact layer with preserved lattice ordering and favorable electrical properties. B ion implantation combined with rapid thermal processing (RTP) achieved acceptor activation and implantation-damage recovery, and the condition with Rp = 198.1 nm showed relatively better structural recovery and electrical characteristics. After introducing the guard-ring electrode, the dark current of the device at −20 V decreased from 6.5 × 10⁻⁹ A to 2.03 × 10⁻⁹ A, and a stable switching current response was obtained under 12 keV monochromatic synchrotron X-ray irradiation. Geant4 simulations were further used as an auxiliary analysis to evaluate the effect of the guard-ring structure on the simulated response spectra and full-energy peak efficiency (FEPE) for low-energy X-rays. Overall, this study provides experimental evidence for process optimization of planar HPGe detectors with low dark current and stable low-energy current response. Full article

Short-wavelength infrared (SWIR) image sensors are of increasing interest for space applications, where ionizing radiation can significantly impact device performance. PbS colloidal quantum dot (CQD)-based thin-film photodiodes (TFPDs) are promising candidates due to their spectral tunability and compatibility with CMOS integration. However, their radiation response remains insufficiently understood. We investigated the effects of X-ray irradiation on PbS CQD-based SWIR TFPDs and image sensors up to a total ionizing dose of 220 krad. The results suggest that X-ray irradiation induces ligand-dependent modulation of the trap-state in PbS CQD films, leading to reduced recombination and enhanced carrier lifetime. Consequently, the TFPDs exhibit decreased dark current and improved external quantum efficiency (EQE), reaching 44.2% at 1420 nm. PbS CQD-based SWIR image sensors maintain stable operation after irradiation until 220 krad, achieving an EQE of 33.1%. These results provide an initial assessment of PbS CQD-based SWIR image sensors under X-ray total ionizing dose (TID) exposure, highlighting the importance of ligand-dependent CQD surface chemistry towards SWIR photodetectors in space applications. Full article

As a typical representative of antibiotic contaminants, tetracycline (TC) remains persistent in surface water and wastewater. Coordination polymers have been confirmed to represent a highly efficient strategy for pollutant removal. In this study, a novel U(VI)-containing polymer, [UO₂(Htci)]·7.5H₂O, was obtained hydrothermally using uranyl nitrate hexahydrate and tris(2-carboxyethyl) isocyanurate (H₃tci). Structural characterization by single-crystal X-ray diffraction indicated a 2D layered crystalline architecture. The compound is interconnected by 3-connected Htci²⁻ anions to afford a characteristic (6, 3) honeycomb topological network. The ligand displayed a special cis-cis-trans conformation, and all carboxylic acid groups were bis-chelating. In addition, the compound was characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction (PXRD), thermal analysis, and photoluminescence spectroscopy. The photodegradation efficiency of TC reached 93.2% after 120 min under irradiation with UV light. At the same time, metal ion sensing of the compound revealed selectivity in recognition of Fe³⁺, with a detection limit of 0.77 mg·L⁻¹ being achieved. Full article

ZnS is one of the most promising wide-bandgap semiconductors for optoelectronic and sensing applications owing to its efficient ultraviolet–blue emission, high exciton binding energy, and chemical stability. However, the synthesis of ZnS nanocrystals in silicon-compatible porous matrices remains largely unexplored. In this work, ordered arrays of ZnS nanocrystals were synthesized for the first time in SiO₂/Si track templates fabricated by swift heavy ion irradiation followed by selective chemical etching. ZnS nanocrystals were deposited by electrochemical deposition from aqueous solutions containing ZnCl₂ and thiourea precursors. The structural, optical, and electrical properties of the resulting ZnS/SiO₂/Si nanocomposites were investigated using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, photoluminescence spectroscopy, and electrical measurements. The fabricated templates contained vertically aligned pores with a density of approximately 10⁸ cm⁻² and an average diameter of about 500 nm. Electrochemical deposition resulted in a pore filling efficiency of approximately 88%. X-ray diffraction analysis confirmed the formation of crystalline ZnS with a cubic zinc blende structure. The nanocomposites exhibit intense ultraviolet–blue photoluminescence in the 335–477 nm range, with pronounced emission peaks at 372 and 400 nm characteristic of ZnS nanocrystals. Current–voltage measurements indicate predominantly electronic conductivity, with a conductivity of 1.54 × 10⁻⁶ Ohm⁻¹·cm⁻¹, comparable to values reported for polycrystalline ZnS films. To support the experimental observations, the electronic structure of ZnS was analyzed using density functional theory within the LCAO framework. The calculated bandgap of 3.4 eV is consistent with previously reported theoretical and experimental data. The obtained results demonstrate that SiO₂/Si track templates provide a promising platform for the fabrication of ordered ZnS nanoarrays with potential applications in silicon-compatible optoelectronic and sensing devices. Full article

The presence of pharmaceuticals in treated wastewater has become an environmental concern due to their persistence, biological activity, and incomplete removal in conventional wastewater treatment systems. In this study, a g-C₃N₄/rGO nanocomposite was synthesized via thermal polycondensation of melamine in the presence of reduced graphene oxide and evaluated as a photocatalyst for the degradation of selected pharmaceuticals in membrane bioreactor (MBR)-treated wastewater. The obtained materials were characterized using Fourier-transform infrared spectroscopy (FTIR–ATR), X-ray diffraction (XRD), nitrogen adsorption–desorption measurements (BET), Raman spectroscopy, scanning electron microscopy (SEM), and UV–Vis spectroscopy to evaluate their chemical structure, crystallinity, textural properties, morphology, and optical characteristics. Photocatalytic experiments were performed under UV irradiation using real wastewater spiked with carbamazepine, diclofenac, ibuprofen, and sulfamethoxazole at an initial concentration of 50 mg/L, selected to ensure reliable quantification under laboratory conditions. The complete removal of diclofenac and sulfamethoxazole was achieved within 30 min of treatment, while the presence of the nanocomposite enhanced the degradation efficiency of ibuprofen and carbamazepine by approximately 19% and 13%, respectively, compared to UV irradiation alone. The obtained results demonstrate the applicability of the investigated g-C₃N₄/rGO system for pharmaceutical degradation in real wastewater matrices and indicate its potential as a preliminary photocatalytic post-treatment approach. Full article

Photothermal-assisted electrocatalysis is an effective approach to enhance the efficiency of the oxygen evolution reaction (OER), but the synergistic mechanism between the photothermal effect and the regulation of catalyst electronic structure remains unclear. This work reports the construction of NiFeS/Cs_0.32WO₃ heterostructures, which integrate interfacial electron transfer and localized surface plasmon resonance (LSPR)-induced photothermal effects to enhance OER performance. The Cs_0.32WO₃ component with hexagonal tungsten bronze structure exhibits strong absorption in the near-infrared region, attributed to LSPR (1100 nm to 2500 nm) and small polaron transition (780 nm to 1100 nm), endowing the NiFeS/Cs_0.32WO₃ composite with excellent photothermal conversion capability. Under 808 nm laser irradiation, the steady-state surface temperature of the heterostructure reaches 65.1 °C. X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy analyses reveal that spontaneous electron transfer from NiFeS to Cs_0.32WO₃ occurs at the heterostructure interface, thereby optimizing the electronic structure of active sites. Electrochemical measurements demonstrate that at a current density of 50 mA cm⁻², the NiFeS/Cs_0.32WO₃ composite exhibits an overpotential of 301 mV under near-infrared irradiation, representing a reduction of 53 mV compared to NiFeS under dark conditions. At a current density of 50 mA cm⁻², the photothermal enhancement effect of the NiFeS/Cs_0.32WO₃ composite is identified as the predominant contributor to the overall performance improvement. Nevertheless, the intrinsic interfacial effect associated with the heterojunction also plays a crucial role and makes a non-negligible contribution to the enhanced electrocatalytic activity. The Tafel slope decreases from 57.8 mV dec⁻¹ to 44.5 mV dec⁻¹ under near-infrared illumination, indicating accelerated OER kinetics. This work elucidates the mechanism of synergistic enhancement between heterostructure construction and photothermal effects, providing insights for the design of advanced photothermal electrocatalysts. Full article

The long-term stability of biodegradable polymer coatings deposited by matrix-assisted pulsed laser evaporation (MAPLE) remains insufficiently understood, particularly under ultraviolet irradiation conditions where photochemical effects may accompany material transfer. In this work, thin films of poly(lactide-co-caprolactone)-block-poly(ethyleneglycol)-block-poly(lactide-co-caprolactone), also known as PLCL-PEG-PLCL, are deposited from chloroform solutions by UV-MAPLE using a nanosecond Nd:YAG laser operating at 266 nm over a wide laser fluence range (0.25–0.9 J/cm²). The effect of laser fluence on the morphological, structural, and chemical evolution of the coatings is investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), focused ion beam scanning electron microscopy (FIB-SEM), and X-ray diffraction (XRD). At low laser fluence, relatively homogeneous coatings are obtained while largely preserving the characteristic functional groups of the triblock copolymer. Increasing the laser fluence progressively induces surface restructuring phenomena, including droplets, wrinkles, and the appearance of highly symmetric faceted structures. These entities develop preferentially in samples deposited at elevated fluence and frequently appear only after prolonged aging under ambient conditions, revealing delayed recrystallization behaviour associated with metastable species generated during the deposition process. EDS analyses reveal localized chlorine enrichment within the faceted structures, while FIB-SEM investigations show porous internal morphologies. XRD confirms that the polymer matrix remains predominantly amorphous. The combined observations suggest that UV-MAPLE deposition from chloroform involves not only physical material transfer but also photochemical processes that promote decomposition, recombination, and delayed crystallization phenomena. A phenomenological model describing the successive stages of surface evolution, aging, and recrystallization is proposed. These results provide new insight into the long-term evolution of laser-deposited biodegradable polymer coatings and highlight the importance of solvent selection and processing conditions in determining their stability. Full article

Metal-free polymeric semiconductor graphitic carbon nitride (g-C₃N₄) was synthesized via thermal polycondensation using cyanamide with PVP as a medium, using SiO₂ nanospheres as sacrificial templates to suppress bulk agglomeration. Structural analysis using X-ray diffraction (XRD) confirmed the conservation of the g-C₃N₄ structure, while diffuse reflectance UV-Vis spectroscopy (DRS) showed that there is a slight change in optical absorption, modifying the band gap energy of g-C₃N₄ with the addition of SiO₂. Transmission electron microscopy (TEM) evidenced the formation of interconnected porous architectures, facilitating charge migration. Photocatalytic activity was evaluated under simulated solar irradiation using acetaminophen (ATP) as a model pharmaceutical pollutant. Kinetics experiments demonstrated that the sample containing 7% SiO₂ nanospheres achieved 65% degradation for 180 min. The best photocatalytic performance is attributed to the pore volume, which favors better adsorption, facilitating the degradation of acetaminophen. The participation of different reactive species during the photocatalytic degradation of ATP was determined. Experiments with scavenger agents indicate that the photogenerated holes are the predominant oxidizing reactive species. These results highlight the potential of g-C₃N₄ modified with SiO₂ nanospheres as an efficient photocatalyst for the degradation of emerging contaminants, thus advancing sustainable water treatment technologies. Full article