Shrimp farming has seen significant growth in recent years, with increased production leading to intensification that requires less area to achieve higher yields. Intensive shrimp farming increases susceptibility to oxidative stress due to hypoxia and thermal fluctuations, compromising productivity and survival. Although α-tocopherol is widely used as a dietary antioxidant, its bioavailability and stability are limited along the intestinal tract. In this study, α-tocopherol was nanoencapsulated in chitosan via ionic gelation to enhance systemic delivery of α-tocopherol in Litopenaeus vannamei, resulting in nanoparticles with a diameter of 150 nanometers. For two weeks, four dietary treatments with five replicates were fed different nanoencapsulated α-tocopherol levels, (0, 2, 3, and 4 mg kg-1). A system of 20-aquariums was used, each aquarium defined as the experimental unit (EU). Prior to the experiment, nanoparticles labeled with fluorescent FITC were used to confirm whether they crossed the intestinal barrier. Gene expression analysis revealed a dose-dependent catalase (CAT) modulation of antioxidant enzymes, such as superoxide dismutase (MnSOD), glutathione peroxidase (GPX), and glutathione S-transferase (GST) in the hepatopancreas, with transcriptional downregulation (qRT-PCR) at higher concentrations, suggesting reduced oxidative pressure or a shift toward pro-oxidant signaling. Despite the short length of the experimental procedure, these findings suggest that nanoencapsulated α-tocopherol not only enhances delivery efficiency but also unveils a redox transition threshold, highlighting the dual antioxidant/pro-oxidant nature of α-tocopherol in vivo. Nanotechnology with biomaterials such as chitosan presents a promising approach to mitigate oxidative stress by enhancing the stability and release of essential antioxidants. Furthermore, this work provides mechanistic insight into nanonutraceutical strategies for oxidative stress management in aquaculture. The pro-oxidant shift under longer experimental procedures is discussed.
Reliable communication systems are critical during emergency scenarios such as floods, earthquakes, fires, and hurricanes to ensure timely information exchange and minimize damage. However, traditional communication infrastructure is often severely compromised during such events. Unmanned Aerial Vehicles (UAVs) have emerged as a promising solution to deploy temporary communication networks in disaster-affected areas. Although several studies have proposed architectures and deployment strategies for UAV-assisted communication, and reviews have addressed their potential, comprehensive discussions on protocol configurations, architectural considerations, and deployment parameter optimization remain limited. This paper presents a systematic literature review covering the period from 2014 to 2024, focusing on the use of UAVs in emergency communication systems. The reviewed articles are classified into a structured taxonomy according to the emergency scenario, UAV role, communication architecture, and protocol layer. Additionally, common communication parameters optimized for deployment, such as coverage and throughput, and the optimization methods employed, including heuristic and artificial intelligence techniques, are identified. The findings reveal that UAVs are predominantly deployed as aerial base stations for large-scale dynamic disasters, with protocol development focusing mainly on the physical, data link, and network layers. However, the lack of standardized deployment guidelines and limited real-world experimentation highlight a significant research gap. This review underscores the need for benchmark methodologies to support the effective and comparable deployment of UAV-assisted emergency communication systems.
The fracture behavior of 3D printed composite materials (3DPCM) remains underexplored, particularly for Onyxbased composites reinforced with continuous Aramid fibers. This study evaluates the interlaminar fracture toughness of Onyx/Aramid composites under Mode I, Mode II, and Mixed-mode I/II loading using Double Cantilever Beam (DCB), End Notch Flexure (ENF), and Mixed-Mode Bending (MMB) methods. Crack initiation and propagation were analyzed for two aramid fiber orientations: 0 degrees and 90 degrees. The results indicate that aramid fiber orientation significantly influences crack growth. Under Mode I, DCB0 degrees and DCB90 degrees samples exhibited similar crack initiation toughness, 1.06 kJ/m2 and 1.62 kJ/m2, respectively. However, crack propagation was more unstable in 90 degrees samples. In Mode II, ENF0 degrees samples exhibited higher fracture toughness 5.36 kJ/m2) than ENF90 degrees 3.72 kJ/m2), demonstrating the effect of reinforcement alignment. Mixed-Mode tests require less energy for crack initiation, 0.98 kJ/m2 for MMB0 degrees and 1.32 kJ/m2 for MMB90 degrees, than Mode I or II, emphasizing the sensitivity of 3DPCM materials to combined tensile-shear loads found in real-world applications. SEM analysis revealed additive manufacturing defects such as voids, fiber breakage, and poor interfacial adhesion, attributed to low pressure during fabrication. These defects lower fracture toughness and contribute to premature failure. This research provides valuable data to the limited literature on Onyx/Aramid 3DPCM and emphasizes the influence of fiber orientation, fracture mode, and processing quality. Further research should focus on optimizing the mixed-mode testing and post-processing techniques that can improve the performance and reliability of final products made by 3DPCM.
