Browsing by resource type "research article"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- The Adaptation of Land Forces to the New Multipolar OrderPublication . Vieira, Ricardo José SimõesThe adaptation of land forces to the new multipolar order is essential for understanding the current dynamics of the International System. This essay analyses the relationship between shifts in global polarity and the reorganisation of land forces, investigating whether strategic competition is driving a return to a conventional era. The research findings indicate that the unipolar era favoured disarmament policies, whereas multipolarity has intensified geopolitical tensions, making military power a central element of state security. The rise of revisionist powers, such as Russia and China, has reinforced the need for conventional rearmament. The 2022 invasion of Ukraine exemplifies this transition, highlighting the renewed relevance of land forces and conventional logistics. A mechanised, division-level military structure has replaced the expeditionary model of the unipolar era. It is concluded that multipolarity drives conventional militarisation, although other factors may also influence this trend.
- Beeswax-enriched tricalcium phosphate/hydroxyapatite/sodium alginate/ thymol 3D-printed scaffolds for application in bone tissue engineeringPublication . Francisco, Martinho Jorge ; Cabral, Cátia Solange Duarte; Calvinho, Paula Cristina Nunes Ferreira ; Correia, Ilídio Joaquim Sobreira ; Moreira, André FerreiraTissue engineering, particularly bone tissue engineering (BTE), continues to pose significant challenges to modern medicine. In this work, a rapid prototyping technique was explored to create 3D scaffolds using a Fab@Home 3D-Plotter extruder. For that purpose, a novel composite mixture containing tricalcium phosphate (TCP), hydroxyapatite (HAp), sodium alginate (SA), beeswax (BW), and thymol (TM) was formulated. BW and TM resulted in 3D scaffolds with rougher surfaces and moderate hydrophilic profiles, properties crucial for mediating cell adhesion and proliferation. Moreover, the 3D scaffolds containing BW displayed a significant increase in compressive strength and Young modulus, being comparable to those exhibited by trabecular bone. TM loading prevented the establishment of Staphylococcus aureus and Escherichia coli infections, inhibiting bacterial adhesion and proliferation at the scaffolds' surface. Additionally, the cytocompatibility of the scaffolds was confirmed over 21 days, with the adhesion and proliferation of Human osteoblasts (hOB) at the scaffold's surfaces. Simultaneously, calcium and phosphate ions accumulated at the scaffolds' surface, forming apatite crystals. Therefore, this improved composite mixture showed promising results for being applied in BTE, not only facilitating hOB cell adhesion and proliferation but also avoiding bacterial infection, addressing a critical challenge in implant-based therapies.
- Dual-crosslinked injectable in situ forming Alginate/CaCl2/Pluronic F127/ α-Cyclodextrin hydrogels incorporating Doxorubicin and graphene-based nanomaterials for cancer chemo-photothermal therapyPublication . Gonçalves, Joaquim; Melo, Bruna Daniela Lopes ; Pouso, Manuel António do Rosário ; Correia, Ilídio Joaquim Sobreira ; de Melo-Diogo, DuarteInjectable in situ forming hydrogels have been emerging due to their capacity to perform the direct delivery of therapeutics into the tumor site with minimal off-target leakage. Particularly, physical crosslinked injectable in situ forming hydrogels are appealing due to their straightforward preparation that exploits the native jointing capabilities of specific polymers/materials. However, the features of these hydrogels (e.g., injectability, degradation, swelling) are strongly pre-determined by the physical interactions available on the selected polymers/ materials, occasionally yielding undesired outcomes. Thus, the combination of multiple physical crosslinking cues may allow the preparation of hydrogels with enhanced properties. In this work, a dual-crosslinked injectable in situ forming hydrogel was engineered by combining Pluronic F127/α-Cyclodextrin and Alginate/CaCl2 (i.e., combination of host-guest and electrostatic interactions), being loaded with Doxorubicin (chemotherapeutic drug) and Dopamine-reduced Graphene Oxide (photothermal nano-agent) for application in cancer chemophotothermal therapy. When compared to the single-crosslinked hydrogels, the dual-crosslinking contributed to the assembly of formulations with suitable injectability and improved degradation and water absorption behaviors. Moreover, the dual-crosslinked hydrogels presented a good photothermal capacity (ΔT ≈ 14 ◦C), leading to a 1.18-times enhanced Doxorubicin release. In in vitro cell-based studies, the dual-crosslinked hydrogels exhibited an excellent cytocompatibility towards healthy (normal human dermal fibroblasts) and breast cancer (MCF-7) cells. As importantly, the dual-crosslinked hydrogels were able to mediate a chemophotothermal effect that diminished the cancer cells’ viability to just 23 %. Overall, the developed dualcrosslinked injectable in situ forming hydrogels incorporating Doxorubicin and Dopamine-reduced Graphene Oxide are a promising macroscale system for breast cancer chemo-photothermal therapy.
- Renewable Photo-Cross-Linkable Polyester-Based Biomaterials: Synthesis, Characterization, and Cytocompatibility AssessmentPublication . Cernadas, Maria Teresa; Pereira, João; Melo, Bruna Daniela Lopes ; de Melo-Diogo, Duarte; Correia, Ilídio Joaquim Sobreira ; Alves, Patrícia; Calvinho, Paula Cristina Nunes FerreiraTThe present work consist of the synthesis of photo-crosslinkable materials, based on unsaturated polyesters (UPs), synthesized from biobased monomers from renewable sources such as itaconic acid and 1,4- butanediol. The UPs were characterized to assess the influence of polycondensation reaction temperature and cross-linking time on their final properties. For this purpose, different UV irradiation exposure periods were tested. Homogeneous, uniform, and transparent films were obtained after 1, 3, and 5 min of UV exposure. These cross-linked films were then characterized. All materials presented high gel content, which was dependent on the reaction’s temperature. The thermal behaviors of the UPs were shown to be similar. In vitro hydrolytic degradation tests showed that the materials can undergo degradation in phosphate-buffered saline (PBS) at pH 7.4 and 37 °C, ensuring their biodegradability over time. Finally, to assess the applicability of the polyesters as biomaterials, their cytocompatibility was determined by using human dermal fibroblasts.
- Traffic Scheduling and Resource Allocation for Heterogeneous Services in 5G New Radio Networks: A Scoping ReviewPublication . Pindi, Ntunitangua René; Velez, Fernando J.The rapid evolution of 5G New Radio networks has introduced a wide range of services with diverse requirements, complicating their coexistence within the shared radio spectrum and posing challenges in traffic scheduling and resource allocation. This study aims to analyze and categorize the methods, approaches, and techniques proposed to ensure efficient joint and dynamic packet scheduling and resource allocation among heterogeneous services—namely eMBB, URLLC, and mMTC—in 5G and beyond, with a focus on Quality of Service and user satisfaction. This scoping review draws from publications indexed in IEEE Xplore and Scopus and synthesizes the most relevant evidence related to packet scheduling across heterogeneous services, highlighting key approaches, core performance metrics, and emerging trends. Following the PRISMA-ScR methodology, 48 out of an initial 140 articles were included for explicitly addressing coexistence, scheduling, and resource allocation. The findings reveal a research emphasis on eMBB and URLLC coexistence, while integration with mMTC remains underexplored. Moreover, the evidence suggests that hybrid and deep learning-based approaches are particularly promising for tackling coexistence and resource management challenges in future mobile networks.