Plastic analysis of steel arches and framed structures with various cross sections

Jéssica L.Silva,Lidiane R.R.M. Deus,Ígor J.M. Lemes,Ricardo A.M. Silveira 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.3

This paper presents a displacement-based numerical methodology following the Euler-Bernoulli theory to simulate the 2 nonlinear behavior of steel structures. It is worth emphasizing the adoption of co-rotational finite element formulations considering large displacements and rotations and an inelastic material behavior. The numerical procedures proposed considers plasticity concentrated at the finite elements nodes, and the simulation of the steel nonlinear behavior is approached via the Strain Compatibility Method (SCM), where the material constitutive relation is used explicitly. The SCM is also applied in determining the sections bearing capacity. Moreover, the present numerical approach is not limited to a specific structural member cross-sectional typology, with the residual stress models introduced explicitly in subareas of steel cross-sections generated by a 2D discretization. Finally, results consistent with the literature and with low processing time are presented.

Cytogenotoxic study of aqueous fruit extract of Morinda citrifolia in Wistar albino rats

Germano Pinho de Moraes,Marcus Vinícius Oliveira Barros de Alencar,Lidiane da Silva Araújo,Débora Cássia Vieira Gomes,Márcia Fernanda Correia Jardim Paz,Muhammad Torequl Islam,Ana Amélia de Carvalho M 경희대학교 융합한의과학연구소 2019 Oriental Pharmacy and Experimental Medicine Vol.19 No.3

The use of herbal products and/or their derivatives as an alternative or complementary medicine becomes globally popular. To date, various biological activities have been reported in Morinda citrifolia Linn, especially antioxidants, antimicrobial, anti-infammatory and antitumor efects. This study aimed to investigate the genotoxicity and DNA repair capacity of the aqueous fruit extract of M. citrifolia (AEMC). Additionally, we checked the mutagenic capacity of AEMC by the comet assay and micronucleus tests in rats. For this, rats (n=10; 5 males and 5 females) were divided into fve groups as: negative control (distilled water); positive control (25 mg/kg of cyclophosphamide, i.p.); and three groups for AEMC (2.5, 5 and 10 mg/kg, i.p.). The results suggest that, the AEMC induced genotoxicity in white blood cells, but a DNA repair capacity was also observed after 72 h of AEMC exposure. AEMC also showed cytotoxicity and mutagenicity in liver and kidney cells of rats at 5 and 10 mg/kg doses. In conclusion, AEMC exhibited a dose-dependent cytotoxicity, genotoxicity and mutagenicity along with a time-dependent DNA repair capacity in rats. Further studies are necessary regarding the safe use of this medicinal plant for human consumption.

Effects of Opuntia ficus-indica lectin on feeding, survival, and gut enzymes of maize weevil, Sitophilus zeamais

Souza, Carolina de Santana,Procopio, Thamara Figueiredo,Belmonte, Bernardo do Rego,Paiva, Patricia Maria Guedes,de Albuquerque, Lidiane Pereira,Pontual, Emmanuel Viana,Napoleao, Thiago Henrique The Korean Society for Applied Biological Chemistr 2018 Applied Biological Chemistry (Appl Biol Chem) Vol.61 No.3

In this study, the effects of Opuntia ficus-indica lectin (OfiL) on the survival and nutritional parameters of Sitophilus zeamais (maize weevil) adults were evaluated. OfiL was incorporated into the artificial diets at concentrations of 15, 60, and 95 mg/g (mg of lectin per g of wheat flour). Mortality was evaluated after 7 and 15 days, and the amount of food ingested and the weight of the insects were determined on the 7th day. In addition, the in vitro effects of OfiL on the gut enzymes of the insect were investigated. The ingestion of OfiL did not show any significant difference in the mortality rates compared to control. The relative consumption rate was also similar to that of the control, and no deterrent effect was detected. However, the values of the relative biomass variation and the efficiency of ingested food conversion were negative in the treatments at 60 and 95 mg/g, showing that lectin ingestion resulted in weight loss. OfiL exhibited a stimulatory effect on the protease activity from S. zeamais gut extract, which may cause uncontrolled hydrolysis of proteins in the digestive tract. This lectin did not promote significant alteration in the amylase activity. In conclusion, OfiL was able to exert anti-nutritional effects without causing a deterrent effect.

Effects of Opuntia ficus-indica lectin on feeding, survival, and gut enzymes of maize weevil, Sitophilus zeamais

Carolina de Santana Souza,Thamara Figueiredo Procopio,Bernardo do Rego Belmonte,Patrıcia Maria Guedes Paiva,Lidiane Pereira de Albuquerque,Emmanuel Viana Pontual,Thiago Henrique Napoleao 한국응용생명화학회 2018 Applied Biological Chemistry (Appl Biol Chem) Vol.61 No.3

In this study, the effects of Opuntia ficus-indica lectin (OfiL) on the survival and nutritional parameters of Sitophilus zeamais (maize weevil) adults were evaluated. OfiL was incorporated into the artificial diets at concentrations of 15, 60, and 95 mg/g (mg of lectin per g of wheat flour). Mortality was evaluated after 7 and 15 days, and the amount of food ingested and the weight of the insects were determined on the 7th day. In addition, the in vitro effects of OfiL on the gut enzymes of the insect were investigated. The ingestion of OfiL did not show any significant difference in the mortality rates compared to control. The relative consumption rate was also similar to that of the control, and no deterrent effect was detected. However, the values of the relative biomass variation and the efficiency of ingested food conversion were negative in the treatments at 60 and 95 mg/g, showing that lectin ingestion resulted in weight loss. OfiL exhibited a stimulatory effect on the protease activity from S. zeamais gut extract, which may cause uncontrolled hydrolysis of proteins in the digestive tract. This lectin did not promote significant alteration in the amylase activity. In conclusion, OfiL was able to exert anti-nutritional effects without causing a deterrent effect.

Effect of Silicon Dioxide and Magnesium Oxide on the Printability, Degradability, Mechanical Strength and Bioactivity of 3D Printed Poly (Lactic Acid)-Tricalcium Phosphate Composite Scaffolds

Harb Samarah V.,Kolanthai Elayaraja,Backes Eduardo H.,Beatrice Cesar A. G.,Pinto Leonardo A.,Nunes Ana Carolina C.,Selistre-de-Araújo Heloisa S.,Costa Lidiane C.,Seal Sudipta,Pessan Luiz Antonio 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.2

Background: Poly (lactic acid) (PLA) is a biodegradable polyester that has been exploited for a variety of biomedical applications, including tissue engineering. The incorporation of β-tricalcium phosphate (TCP) into PLA has imparted bioactivity to the polymeric matrix. Methods: We have modified a 90%PLA-10%TCP composite with SiO2 and MgO (1, 5 and 10 wt%), separately, to further enhance the material bioactivity. Filaments were prepared by extrusion, and scaffolds were fabricated using 3D printing technology associated with fused filament fabrication. Results: The PLA-TCP-SiO2 composites presented similar structural, thermal, and rheological properties to control PLA and PLA-TCP. In contrast, the PLA-TCP-MgO composites displayed absence of crystallinity, lower polymeric molecular weight, accelerated degradation ratio, and decreased viscosity within the 3D printing shear rate range. SiO2 and MgO particles were homogeneously dispersed within the PLA and their incorporation increased the roughness and protein adsorption of the scaffold, compared to a PLA-TCP scaffold. This favorable surface modification promoted cell proliferation, suggesting that SiO2 and MgO may have potential for enhancing the bio-integration of scaffolds in tissue engineering applications. However, high loads of MgO accelerated the polymeric degradation, leading to an acid environment that imparted the composite biocompatibility. The presence of SiO2 stimulated mesenchymal stem cells differentiation towards osteoblast; enhancing extracellular matrix mineralization, alkaline phosphatase (ALP) activity, and bone-related genes expression. Conclusion: The PLA-10%TCP-10%SiO2 composite presented the most promising results, especially for bone tissue regeneration, due to its intense osteogenic behavior. PLA-10%TCP-10%SiO2 could be used as an alternative implant for bone tissue engineering application. Background: Poly (lactic acid) (PLA) is a biodegradable polyester that has been exploited for a variety of biomedical applications, including tissue engineering. The incorporation of β-tricalcium phosphate (TCP) into PLA has imparted bioactivity to the polymeric matrix. Methods: We have modified a 90%PLA-10%TCP composite with SiO2 and MgO (1, 5 and 10 wt%), separately, to further enhance the material bioactivity. Filaments were prepared by extrusion, and scaffolds were fabricated using 3D printing technology associated with fused filament fabrication. Results: The PLA-TCP-SiO2 composites presented similar structural, thermal, and rheological properties to control PLA and PLA-TCP. In contrast, the PLA-TCP-MgO composites displayed absence of crystallinity, lower polymeric molecular weight, accelerated degradation ratio, and decreased viscosity within the 3D printing shear rate range. SiO2 and MgO particles were homogeneously dispersed within the PLA and their incorporation increased the roughness and protein adsorption of the scaffold, compared to a PLA-TCP scaffold. This favorable surface modification promoted cell proliferation, suggesting that SiO2 and MgO may have potential for enhancing the bio-integration of scaffolds in tissue engineering applications. However, high loads of MgO accelerated the polymeric degradation, leading to an acid environment that imparted the composite biocompatibility. The presence of SiO2 stimulated mesenchymal stem cells differentiation towards osteoblast; enhancing extracellular matrix mineralization, alkaline phosphatase (ALP) activity, and bone-related genes expression. Conclusion: The PLA-10%TCP-10%SiO2 composite presented the most promising results, especially for bone tissue regeneration, due to its intense osteogenic behavior. PLA-10%TCP-10%SiO2 could be used as an alternative implant for bone tissue engineering application.