How does urbani(s)zation affect the bird diversity?: a bibliometric aided comprehensive analysis

Urbani(s)zation is characterized by habitat loss and fragmentation, posing critical challenges to bird diversity. Here, we have designed a comprehensive bibliometric analysis to identify the core content and trend themes in urbanisation and diversity. In this context, the present review integrates a bibliometric analysis of 386 scientific documents published between 1989 and 2023, reporting a comprehensive overview of global research trends on this critical topic. The findings of the study revealed that the annual publication rate has surged since 2001, with peaks in 2013 (28 documents) and 2022 (35 documents), reflecting growing scholarly interest. Concerning the spatial distribution of the documents analysed, the United States topped with 127 publications (32.9%), followed by Australia (50; 12.9%), Canada (36; 9.3%), and the United Kingdom (32; 8.3%). Regarding bird taxa, Passeriformes, particularly the family Pariidae, dominate studies in this field. As of the core content of the studies, keyword cluster analysis identified four major themes, viz. i) environmental impacts, ii) conservation biology, iii) urban ecology, and iv) human-wildlife conflict, reflecting diverse research focuses on avian adaptation, behavioral changes, and species declines in urban settings. The analyses revealed that a significant portion of the scientific documents were published in six journals, namely “Landscape and Urban Planning,” “Biological Conservation,” “Landscape Ecology,” “Conservation Biology,” “Plos One,” and “Urban Ecosystems”. Critically, the predominant themes of the documents were linked to “Environmental Science,” “Agricultural and Biological Sciences,” “Social Science,” “Biochemistry, Genetics and Molecular Biology,” and “Earth and Planetary Sciences,” each addressing various impacts from habitat loss to social interactions and genetic changes. The study also provides practical recommendations for the conservation and management of urban bird biodiversity, highlighting the importance of green infrastructure initiatives, citizen science projects and interdisciplinary collaboration

Sustainable hybrid epoxy composites with natural fillers for radiation shielding applications

This study presents the systematic development and in-depth characterization of novel, sustainable, and lightweight hybrid epoxy composites reinforced with mahogany wood, periwinkle shell, and granite particles. These composites were specifically engineered for dual-function gamma-ray and fast neutron shielding applications. The materials were synthesized using varying filler mass fractions (10–20 wt%) and particle sizes (100 µm and 700 µm) under a Taguchi L4 orthogonal design to ensure optimized performance. FTIR spectroscopy confirmed that the chemical treatment of mahogany wood successfully removed organic compounds such as lignin, cellulose, and hemicellulose, thereby enhancing the interfacial bonding between fillers and the epoxy matrix. SEM and EDX analyses showed uniform filler distribution with minimal voids and revealed elemental contributions from high-Z elements like calcium and silicon, which are critical for radiation attenuation. Gamma-ray shielding performance was evaluated using a calibrated Ba-133 radioactive source covering energies from 81 to 383 keV. Among all tested samples, the A4 composite (700 µm, 20 wt%) displayed the best performance, achieving mass attenuation coefficients (MAC) ranging from 0.1939 to 0.0984 cm2/g. This composite also demonstrated the lowest half-value layer (HVL) and buildup factors, along with the highest effective atomic number (Zeff), confirming its superior photon attenuation efficiency. These results highlight the impact of both high-Z content and optimized particle size on enhancing photon interaction probabilities and reducing secondary radiation hazards. In addition, neutron shielding capability was assessed using a 4.5 MeV Am-Be neutron source. The removal cross sections (ΣR) for composites A3 and A4 were found to be 0.08313 cm⁻1 and 0.0758 cm⁻1, respectively, values that approach those of standard materials like graphite (0.07773 cm⁻1) and water (0.1023 cm⁻1). Furthermore, absorbed neutron dose measurements demonstrated a significant increase from 5.92% in A1 to 22.08% in A4, indicating enhanced neutron attenuation due to the synergistic effects of hydrogen-rich wood and calcium-rich shell fillers. These findings suggest that integrating both organic and inorganic bio-based fillers yields environmentally friendly composites with excellent gamma and neutron shielding properties. The combination of radiation attenuation efficiency, lightweight nature, cost-effectiveness, and sustainability makes these composites attractive candidates for practical applications in nuclear medicine, aerospace systems, radiological protection, and industrial shielding

Revisiting Reaction Mechanism of Regioselective Disulfide-Catalyzed Photocatalytic Aerobic Oxidative Cleavage of 1-Arylbutadienes: A Computational Study

A computational study of the regioselective aerobic oxidative cleavage of 1-arylbutadienes is carried out employing density functional theory and high-level coupled-cluster methods, such as coupled-cluster singles and doubles with perturbative triples [CCSD(T)]. The results demonstrate that the reaction proceeds either via the intramolecular reduction or dimerization of peroxyl radical. These findings are in contrast to a previously proposed mechanism that progresses via formation of the dioxetane ring. The computations further indicate that the homolysis of S-S bond of diaryl disulfide derivatives cannot be achieved by irradiation with direct visible light under the reaction conditions due to the high bond dissociation energy