Overcoming brittleness through bioinspiration and -microarchitecture

The fracture of highly mineralized natural materials such as bone, teeth, or seashells is largely controlled by the interfaces they contain. These interfaces, relatively weak, deflect and guide cracks into configurations which eventually impede their propagation. As a result, weaker interfaces turn brittle minerals into tough materials which can deform and absorb energy from impacts. To explore these concepts in synthetic materials, we used a 3D laser-engraver to carve arrays of microcracks with well-defined geometries and toughness within the bulk of borosilicate glass slides. The microcracks, positioned along specific surfaces within the material, coalesce upon application of an external load and guide large cracks following the concept of “stamp holes”. Using this approach, we engraved curved interfaces with re-entrant features ahead of an incident crack in glass, defining jigsaw-like building blocks. After initial crack propagation along the weak interface, the jigsaw features produced a tremendous amount of toughness by pull out and interlocking, dissipating energy by friction. This powerful nonlinear failure mechanism, inspired by natural nacre, amplified the toughness of glass 100x. Infiltration of the interfaces with polyurethane generatedadditional toughening mechanisms by ligament bridging, similar to the mechanism of proteins in hard biological materials. This additional step led to a material made of ~95% of glass but 200x tougher, as stiff as plain glass but displaying nonlinear deformations and failing at strains in excess of 3%. This bioinspired glass not only shows how the powerful toughening mechanisms observed in nature can be harnessed in synthetic materials, but also showcase a new approach to making bioinspired composite materials by “fabricating” weak interfaces within stiff materials rather than assembling stiff building blocks within soft matrices

Total Blindness Following Anaphylactic Shock due to Co-Amoxiclav Treatment

Anaphylactic shock is a rare but severe allergic reaction most often caused by an allergy to food, insect bites, or certain medications. Co-amoxiclav is an antibiotic medication used to treat many bacterial infections. In the present work, the authors report an 82-year-old female patient suffering from total blindness after anaphylactic shock after taking the first dose of co-amoxiclav

On a 3D material modelling of smart nanocomposite structures

Smart composites (SCs) are utilized in electro-mechanical systems such as actuators and energy harvesters. Typically, thin-walled components such as beams, plates, and shells are employed as structural elements to achieve the mechanical behavior desired in these composites. SCs exhibit various advanced properties, ranging from lower order phenomena like piezoelectricity and piezomagneticity, to higher order effects including flexoelectricity and flexomagneticity. The recently discovered flexomagneticity in smart composites has been investigated under limited conditions. A review of the existing literature indicates a lack of evaluation in three-dimensional (3D) elasticity analysis of SCs when the flexomagnetic effect (FM) exists. To address this issue, the governing equations will incorporate the term ∂/∂z, where z represents the thickness coordinate. The variational technique will guide us in further developing these governing equations. By using hypotheses and theories such as a 3D beam model, von Kármán's strain nonlinearity, Hamilton's principle, and well-established direct and converse FM models, we will derive the constitutive equations for a thick composite beam. Conducting a 3D analysis implies that the strain and strain gradient tensors must be expressed in 3D forms. The inclusion of the term ∂/∂z necessitates the construction of a different model. It should be noted that current commercial finite element codes are not equipped to accurately and adequately handle micro- and nano-sized solids, thus making it impractical to model a flexomagnetic composite structure using these programs. Therefore, we will transform the derived characteristic linear three-dimensional bending equations into a 3D semi-analytical Polynomial domain to obtain numerical results. This study demonstrates the importance of conducting 3D mechanical analyses to explore the coupling effects of multiple physical phenomena in smart structures

Discrete Optimum Design of Planar Steel Curved Roof and Pitched Roof Portal Frames Using Metaheuristic Algorithms

Portal frames are single-story frame buildings including columns and rafters, and their rafters can be either curved or pitched. These are used widely in the construction of industrial buildings, warehouses, gyms, fire stations, agricultural buildings, hangars, etc. The construction cost of these frames considerably depends on their weight. In the present research, the discrete optimum design of two types of portal frames including planar steel Curved Roof Frame (CRF) and Pitched Roof Frame (PRF) with tapered I-section members are presented. The optimal design aims to minimize the weight of these frame structures while satisfying some design constraints based on the requirements of ANSI/AISC 360-16 and ASCE 7-10. Four population-based metaheuristic optimization algorithms are applied to the optimal design of these frames. These algorithms consist of Teaching-Learning-Based Optimization (TLBO), Enhanced Colliding Bodies Optimization (ECBO), Shuffled Shepherd Optimization Algorithm (SSOA), and Water Strider Algorithm (WSA). Two main objectives are followed in this paper. The first one deals with comparing the optimized weight of the CRF and PRF structures with the same dimensions for height and span in two different span lengths (16.0 m and 32.0 m), and the second one is related to comparing the performance of the considered metaheuristics in the optimum design of these portal frames. The obtained results reveal that CRF is more economical than PRF in the fair comparison. Moreover, comparing the results acquired by SSOA with those of other considered metaheuristics reveals that SSOA has better performance for the optimal design of these portal frames

A Human-Centric Approach to Group-Based Context-Awareness

The emerging need for qualitative approaches in context-aware information processing calls for proper modeling of context information and efficient handling of its inherent uncertainty resulted from human interpretation and usage. Many of the current approaches to context-awareness either lack a solid theoretical basis for modeling or ignore important requirements such as modularity, high-order uncertainty management and group-based context-awareness. Therefore, their real-world application and extendability remains limited. In this paper, we present f-Context as a service-based context-awareness framework, based on language-action perspective (LAP) theory for modeling. Then we identify some of the complex, informational parts of context which contain high-order uncertainties due to differences between members of the group in defining them. An agent-based perceptual computer architecture is proposed for implementing f-Context that uses computing with words (CWW) for handling uncertainty. The feasibility of f-Context is analyzed using a realistic scenario involving a group of mobile users. We believe that the proposed approach can open the door to future research on context-awareness by offering a theoretical foundation based on human communication, and a service-based layered architecture which exploits CWW for context-aware, group-based and platform-independent access to information systems

EverLight: Indoor-Outdoor Editable HDR Lighting Estimation

Because of the diversity in lighting environments, existing illumination estimation techniques have been designed explicitly on indoor or outdoor environments. Methods have focused specifically on capturing accurate energy (e.g., through parametric lighting models), which emphasizes shading and strong cast shadows; or producing plausible texture (e.g., with GANs), which prioritizes plausible reflections. Approaches which provide editable lighting capabilities have been proposed, but these tend to be with simplified lighting models, offering limited realism. In this work, we propose to bridge the gap between these recent trends in the literature, and propose a method which combines a parametric light model with 360{\deg} panoramas, ready to use as HDRI in rendering engines. We leverage recent advances in GAN-based LDR panorama extrapolation from a regular image, which we extend to HDR using parametric spherical gaussians. To achieve this, we introduce a novel lighting co-modulation method that injects lighting-related features throughout the generator, tightly coupling the original or edited scene illumination within the panorama generation process. In our representation, users can easily edit light direction, intensity, number, etc. to impact shading while providing rich, complex reflections while seamlessly blending with the edits. Furthermore, our method encompasses indoor and outdoor environments, demonstrating state-of-the-art results even when compared to domain-specific methods.Comment: 11 pages, 7 figure

A Case of Peripheral Ulcerative Keratitis Associated with Autoimmune Hepatitis

Purpose. To describe a case of peripheral ulcerative keratitis in the setting of autoimmune hepatitis and possible overlap syndrome with primary sclerosing cholangitis. Case Report. A 48-year-old African American female with autoimmune hepatitis with possible overlap syndrome with primary sclerosing cholangitis presented with tearing, irritation, and injection of the left eye that was determined to be peripheral ulcerative keratitis. The patient was treated with topical and systemic steroids, immunosuppressant drugs (azathioprine and mycophenolate mofetil), a biologic (rituximab), and surgery (conjunctival resection), and the peripheral ulcerative keratitis epithelialized but ultimately led to corneal perforation. Conclusion. In this unique case, a patient with peripheral ulcerative keratitis who underwent treatment ultimately had a corneal perforation. This case may suggest a possible relationship between autoimmune hepatitis and peripheral ulcerative keratitis