Halfa grass (Desmostachya bipinnata) is an abundant lignocellulosic biomass with potential for thermochemical conversion and biochar production. This study investigated its physicochemical characteristics, pyrolysis kinetics, reaction mechanism, and thermodynamic behavior using an integrated experimental approach. Elemental analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to characterize the biomass and the derived biochar. Thermogravimetric analysis (TGA) was conducted under a nitrogen atmosphere at heating rates of 10, 20, and 30°C min⁻¹. The TG–DTG profiles revealed a typical multi-stage decomposition pattern associated with the degradation of hemicellulose, cellulose, and lignin fractions. The activation energy was determined using Flynn–Wall–Ozawa (FWO), Friedman (FM), Kissinger, and Vyazovkin (VYZ) methods. The average activation energies obtained from the FWO, FM, VYZ, and Kissinger methods were 144.28, 151.09, 150.79, and 156.00 kJ mol⁻¹, respectively, demonstrating good agreement among the applied kinetic approaches. The variation of activation energy with conversion confirmed that halfa grass pyrolysis proceeds through multiple overlapping reactions rather than a single elementary process. Master plot analysis indicated that diffusion-related models provided the closest agreement with the experimental data over different conversion ranges, although additional validation would be required for definitive mechanistic confirmation. Thermodynamic analysis revealed positive enthalpy and Gibbs free energy values, indicating that the decomposition process is endothermic and requires continuous energy input. FTIR and XRD analyses demonstrated substantial structural transformation during pyrolysis, including the decomposition of oxygen-containing functionalities and the formation of condensed aromatic carbon structures within the resulting biochar. These results provide valuable insight into the thermal decomposition behavior of D. bipinnata and contribute to a better understanding of its physicochemical and kinetic characteristics for future thermochemical conversion and biomass valorization applications.

Background Mosquitoes pose a significant threat as vectors for numerous human and animal diseases, particularly in tropical and subtropical regions, including Egypt. Given the prevalence of mosquito-borne diseases and the documented high densities of Culex pipiens in Assiut Governorate, there is a critical need for environmentally friendly mosquito management strategies. This study aimed to identify the morphogenetic and determine the enzymatic potential of native fungal isolates associated with mosquitoes in Assiut Governorate. Results Eight distinct fungal species were successfully characterized based on their morphological traits and ITS rDNA sequence data. These species were identified as Alternaria tenuissima, Trichoderma hamatum, Purpureocillium lilacinum, Geotrichum candidum, and four Fusarium species (F. oxysporum, F. solani, F. equiseti, and F. incarnatum). The results of enzymatic screening emphasize that twenty-two fungal isolates belonging to eight species had the biochemical machinery substantial for cuticle degeneration, with various levels of phospholipase, lipase, protease, and chitinase activities. The strongest synergistic enzymatic profiles were notably displayed by P. lilacinum and F. equiseti. Conclusion The extensive morphological and molecular description and enzymatic detection provide crucial promotion for evaluating the potential of these local fungal isolates for future sustainable insect pest management in the specific ecological context of Assiut Governorate.

To cope with severe seasonal changes in climate and food availability, colonies of Apis mellifera L. generate two distinct worker phenotypes during winter and summer. The aim of this research was to evaluate the effect of oral exposure to insecticides on the toxic susceptibility of winter and summer honeybee workers (Apis mellifera L.) under laboratory conditions. In this work, under all tested conditions and seasons, emamectin benzoate was the most toxic compound and used as the standard (Toxicity Index = 100) for comparison with other compounds. It had the lowest LC50 (Lethal Concentration required to kill 50% of the tested honeybees) values, which decreased to 0.004 mg/L in winter bees after 48 h following oral exposure. Sulfoxaflor had moderate toxicity, and indoxacarb was the least toxic to honeybees. The results also revealed that the toxic effect was time-dependent, with lethal concentrations at 48 h significantly lower than those at 24 h. In addition, seasonal effects play a role; winter honeybees were, overall, more sensitive to the treatments than summer honeybees. Under the conditions of this study, it can be concluded that emamectin benzoate was the most toxic substance and indoxacarb the least toxic. Toxicity increased with exposure time. Winter honeybees showed greater sensitivity than summer honeybees. A field-relevant Hazard Quotient (HQ) analysis further indicated that indoxacarb, despite its lower acute toxicity, exhibited the narrowest margin relative to field-recommended spray concentrations, highlighting the value of incorporating field-relevant exposure metrics alongside LC50-based rankings in pollinator risk assessment. It is worth clarifying that this narrower margin reflects indoxacarb’s higher field-recommended application rate relative to its LC50, rather than a greater intrinsic toxicity than emamectin benzoate, and the two aspects of risk (intrinsic toxicity vs. use-rate-based field risk) should be interpreted separately.