Phase-field modeling of constrained interactive fungal networks.

Fungi develop structures that interact with their surroundings and evolve adaptively in the presence of geometrical constraints, finding optimal solutions for complex combinatorial problems. The pathogenic fungus Ophiocordyceps constitutes a perfect model for the study of constrained interactive networks. Modeling these networks is challenging due to the highly coupled physics involved and their interaction with moving boundaries. In this work, we develop a computational phase-field model to elucidate the mechanics of the emerging properties observed in fungal networks. We use a variational approach to derive the equations governing the evolution in time of the mycelium biomass and the nutrients in the medium. We present an extensive testing of our model, reproduce growing and decaying phenomena, and capture spatial and temporal scales. We explore the variables interplay mechanism that leads to different colony morphologies, and explain abrupt changes of patterns observed in the laboratory. We apply our model to simulate analogous processes to the evolution of Ophiocordyceps as it grows through confined geometry and depletes available resources, demonstrating the suitability of the formulation to study this class of biological networks.

Nested structure role in the mechanical response of spicule inspired fibers.

Euplectella aspergillummarine sponge spicules are renowned for their remarkable strength and toughness. These spicules exhibit a unique concentric layering structure, which contributes to their exceptional mechanical resistance. In this study, finite element method simulations were used to comprehensively investigate the effect of nested cylindrical structures on the mechanical properties of spicules. This investigation leveraged scanning electron microscopy images to guide the computational modeling of the microstructure and the results were validated by three-point bending tests of 3D-printed spicule-inspired structures. The numerical analyses showed that the nested structure of spicules induces stress and strain jumps on the layer interfaces, reducing the load on critical zones of the fiber and increasing its toughness. It was found that this effect shows a tapering enhancement as the number of layers increases, which combines with a threshold related to the 3D-printing manufacturability to suggest a compromise for optimal performance. A comprehensive evaluation of the mechanical properties of these fibers can assist in developing a new generation of bioinspired structures with practical real-world applications.

Fascitis necrosante en un niño. Evolución y tratamiento / Necrotizing fasciitis in a child. Evolution and treatment

La fascitis necrosante es una grave infección de progresión rápida y fulminante. Debe ser sospechada ante la progresión de lesiones dérmicas con necrosis de tejidos y afectación del estado general. En los niños no requiere una situación de inmunodepresión ni enfermedad de base. El tratamiento de elección es el abordaje quirúrgico precoz con desbridamiento amplio de la zona afectada. La situación funcional tras el tratamiento puede verse mermada. Presentamos un caso de fascitis necrosante en un niño, su evolución, el tratamiento y el abordaje rehabilitador tras la cirugía (AU)

Necrotizing fasciitis is a serious bacterial infection with rapid progression and fulminant course. It should be suspected in patients with rapidly progressing skin lesions with soft tissue necrosis and deterioration of general health status. This infection can occur in children without immunodepression or underlying diseases. The treatment of choice is wide surgical debridement of dead tissue. Functional recovery after treatment may be limited. We report a case of necrotizing fasciitis in a boy and his outcome, as well as the treatment of this infection and the approach to rehabilitation after surgery (AU)