2D evaluation of crack openings using smeared and embedded crack models

André Luís Gamino,Osvaldo Luís Manzoli,José Luiz Antunes de Oliveira e Sousa,Túlio Nogueira Bittencourt 사단법인 한국계산역학회 2010 Computers and Concrete, An International Journal Vol.7 No.6

This work deals with the determination of crack openings in 2D reinforced concrete structures using the Finite Element Method with a smeared rotating crack model or an embedded crack model. In the smeared crack model, the strong discontinuity associated with the crack is spread throughout the finite element. As is well known, the continuity of the displacement field assumed for these models is incompatible with the actual discontinuity. However, this type of model has been used extensively due to the relative computational simplicity it provides by treating cracks in a continuum framework, as well as the reportedly good predictions of reinforced concrete members’ structural behavior. On the other hand, by enriching the displacement field within each finite element crossed by the crack path, the embedded crack model is able to describe the effects of actual discontinuities (cracks). This paper presents a comparative study of the abilities of these 2D models in predicting the mechanical behavior of reinforced concrete structures. Structural responses are compared with experimental results from the literature, including crack patterns, crack openings and rebar stresses predicted by both models.

Pharmacological Treatment of Acute Unilateral Vestibulopathy: A Review

Sousa Francisco Alves de,Alves Clara Serdoura,Pinto Ana Nóbrega,Meireles Luís,Rego Ângela Reis 대한청각학회 2024 Journal of Audiology & Otology Vol.28 No.1

There have been few investigations on the epidemiology, etiology, and medical management of acute unilateral vestibulopathy (AUV). Short-term pharmaceutical resolutions include vestibular symptomatic suppressants, anti-emetics, and some cause-based therapies. Anticholinergics, phenothiazines, antihistamines, antidopaminergics, benzodiazepines, and calcium channel antagonists are examples of vestibular suppressants. Some of these medications may show their effects through multiple mechanisms. In contrast, N-acetyl-L-leucine, Ginkgo biloba, and betahistine improve central vestibular compensation. Currently, AUV pathophysiology is poorly understood. Diverse hypotheses have previously been identified which have brought about some causal treatments presently used. According to some publications, acute administration of anti-inflammatory medications may have a deleterious impact on both post-lesional functional recovery and endogenous adaptive plasticity processes. Thus, some authors do not recommend the use of corticosteroids in AUV. Antivirals are even more contentious in the context of AUV treatment. Although vascular theories have been presented, no verified investigations employing anti-clotting or vasodilator medications have been conducted. There are no standardized treatment protocols for AUV to date, and the pharmacological treatment of AUV is still questionable. This review addresses the most current developments and controversies in AUV medical treatment.

Finite element computational modeling of externally bonded CFRP composites flexural behavior in RC beams

André Luís Gamino,Túlio Nogueira Bittencourt,José Luiz Antunes de Oliveira e Sousa 사단법인 한국계산역학회 2009 Computers and Concrete, An International Journal Vol.6 No.3

This paper focuses on the flexural behavior of RC beams externally strengthened with Carbon Fiber Reinforced Polymers (CFRP) fabric. A non-linear finite element (FE) analysis strategy is proposed to support the beam flexural behavior experimental analysis. A development system(QUEBRA2D/FEMOOP programs) has been used to accomplish the numerical simulation. Appropriate constitutive models for concrete, rebars, CFRP and bond-slip interfaces have been implemented and adjusted to represent the composite system behavior. Interface and truss finite elements have been implemented (discrete and embedded approaches) for the numerical representation of rebars, interfaces and composites.

Diversity minimization through part combination – a Portuguese railway infrastructure case study

Diogo Rechena,Luís Sousa,Virgínia Infante,Elsa Henriques 한국CDE학회 2020 Journal of computational design and engineering Vol.7 No.1

With increasing market needs for product and service variety, companies struggle to provide diversity in cost-effective ways. Through standardization of components with a low perceived added value, companies can take advantage of economies of scale while maintaining product diversity. Railway infrastructure managers face similar challenges of providing economically sustainable services while dealing with the costs of maintaining the system diversity. Typically, unintended design diversity stems from design practices in which existing solutions are not reused for new problems and new solutions are rarely planned considering the dynamics of requirement changes. In this paper we provide a methodology to assess how to standardize different designs to minimize design diversity and to assess design divergence in a product family. The developed methodology is able to take into account any set of standardization compatibility constraints that the user can define. The methodology was applied in the context of a small-scale railway infrastructure manager using a dataset of 223 unique designs of functionally similar components from its electrification system. Depending on the activated compatibility constraints, results indicate that over 60% of components can be reduced to a set of 86 unique designs.

Anthraquinone as emerging contaminant: technological, toxicological, regulatory and analytical aspects

Valduga Alice Teresa,Gonçalves Itamar Luís,Saorin Puton Bruna Maria,de Lima Hennig Bruna,Sousa de Brito Edy 한국독성학회 2024 Toxicological Research Vol.40 No.1

Anthraquinone (anthracene-9,10-dione) is a multifaceted chemical used in the paper industry, in the production of synthetic dyes, in crop protection against birds and is released from fossil fuels. Additionally, the anthraquinone scaffold, when substituted with sugars and hydroxyl groups is found in plants as metabolites. Because of these multiple applications, it is produced on a large scale worldwide. However, its toxicological aspects have gained interest, due to the low limits in the foods defined by legislation. Worrying levels of anthracene-9,10-dione have been detected in wastewater, atmospheric air, soil, food packaging and more recently, in actual foodstuffs. Recent investigations aiming to identify the anthracene-9,10-dione contamination sources in teas highlighted the packaging, leaves processing, anthracene metabolism, reactions between tea constituents and deposition from the environment. In this context, this review seeks to highlight the uses, sources, biological effects, analytical and regulatory aspects of anthracene-9,10-dione.

Boron nitride nanotube-CREKA peptide as an effective target system to metastatic breast cancer

Ferreira Tiago Hilário,de Oliveira Freitas Luiza Baptista,Fernandes Renata Salgado,dos Santos Virgílio Mateus,Resende Jarbas Magalhães,Cardoso Valbert Nascimento,de Barros André Luís Branco,de Sousa E 한국약제학회 2020 Journal of Pharmaceutical Investigation Vol.50 No.5

Purpose The development of nanomaterials that are capable of recognizing disease-specific biomarkers with high sensitivity and specificity is related to several advances in the field of nanomedicine. Furthermore, the targeted delivery of anticancer agents to tumor tissues enhances their efficiency and reduces their toxic side effects. Boron nitride nanotubes (BNNTs) are nanostructured materials, analog to carbon nanotubes, which present good biocompatibility and morphology suitable for tumor cell internalization. CREKA is a pentapeptide that has a high affinity to fibrin, a protein found in the new tumor vessels in the early stages of metastasis and in thrombosis regions. Methods In this study BNNTs were chemically functionalized with the peptide CREKA, and this system was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zeta potential, scanning electron microscopy, and transmission electron microscopy. Results After the mentioned chemical steps, the FTIR analysis shows an organic phase related to the CREKA, TGA indicates that about 10% of the peptide is firmly attached to BNNT surface. In addition, the radiolabeling process was successful, achieving the purity required for the biodistribution study. In vivo experiments showed that a considerable amount of BNNTCREKA was accumulated at the tumor and metastasis sites. Conclusion The present results indicate an effective targeting of the system to tumor and metastasis sites. Further studies can reveal potential applications of functionalized BNNTs in cancer treatment.

Sensory neurons and osteoblasts: close partners in a microfluidic platform

Neto, Estrela,Alves, Cecí,lia J.,Sousa, Daniela M.,Alencastre, Inê,s S.,Lourenç,o, Ana H.,Leitã,o, Luí,s,Ryu, Hyun R.,Jeon, Noo L.,Fernandes, Rui,Aguiar, Paulo,Almeida, Ra Oxford University Press 2014 Integrative biology Vol.6 No.6

<P>Innervation has proven to be critical in bone homeostasis/regeneration due to the effect of soluble factors, produced by nerve fibers, associated with changes in the activity of bone cells. Thus, in this study, we have established and characterized a coculture system comprising sensory neurons and osteoblasts to mimic the <I>in vivo</I> scenario where nerve fibers can be found in a bone microenvironment. Embryonic or adult primary dorsal root ganglion (DRG) and MC3T3-E1 osteoblastic cells were cocultured in compartmentalized microfluidic platforms and morphological and functional tests were performed. The time of adhesion and readout of axonal outgrowth were improved by the alignment of DRG with the axis of microgrooves, which showed to be a crucial step for the designed experiments. Cocultures of entire DRG from adult origin with osteoblasts were performed, showing extended DRG projections towards the axonal compartment, reaching osteoblastic cells. Immunocytochemistry showed that the neurites present within the osteoblastic compartment were immunoreactive to synapsin and calcitonin gene-related peptide suggesting the presence of specialized structures involved in this crosstalk. This evidence was further confirmed by electron microscopy where varicosities were detected as well as electron dense structures in neurite membranes. Aiming to mimic the properties of tissue extracellular matrices, MC3T3-E1 cells were seeded in the axonal side upon laminin, collagen or within 3D functionalized alginate matrices and axonal outgrowth was clearly observed. In order to analyze and quantify data with reproducible image analysis, a semi-automated algorithm was also developed. The collagen and laminin substrates displayed a higher amount of axons reaching the axonal side. Overall, the established method revealed to be a suitable tool to study the interaction between the peripheral nervous system and bone cells in different contexts mimicking the <I>in vivo</I> scenario.</P>