Prediction of the mechanical properties of granites under tension using DM techniques

Martins, Francisco F.,Vasconcelos, Graca,Miranda, Tiago Techno-Press 2018 Geomechanics & engineering Vol.15 No.1

The estimation of the strength and other mechanical parameters characterizing the tensile behavior of granites can play an important role in civil engineering tasks such as design, construction, rehabilitation and repair of existing structures. The purpose of this paper is to apply data mining techniques, such as multiple regression (MR), artificial neural networks (ANN) and support vector machines (SVM) to estimate the mechanical properties of granites. In a first phase, the mechanical parameters defining the complete tensile behavior are estimated based on the tensile strength. In a second phase, the estimation of the mechanical properties is carried out from different combination of the physical properties (ultrasonic pulse velocity, porosity and density). It was observed that the estimation of the mechanical properties can be optimized by combining different physical properties. Besides, it was seen that artificial neural networks and support vector machines performed better than multiple regression model.

Characterization of Aspartate Aminotransferase Isoenzymes from Leaves of Lupinus albus L. cv Estoril

Martins, Maria Luisa Louro,De Freitas Barbosa, Miguel Pedro,De Varennes E Mendonca, Amarilis Paula Alberti Korean Society for Biochemistry and Molecular Biol 2002 Journal of biochemistry and molecular biology Vol.35 No.2

Two aspartate aminoransferase (EC 2.6.1.1) isoenzymes (AAT-1 and AAT-2) from Lupinus albus L. cv Estoril were separated, purified, and characterized. The molecular weight, pI value, optimum pH, optimum temperature, and thermodynamic parameters for thermal inactivation of both isoenzymes were obtained. Studies of the kinetic mechanism, and the kinetics of product inhibition and high substrate concentration inhibition, were performed. The effect of some divalent ions and irreversible inhibitors on both AAT isoenzymes was also studied. Native PAGE showed a higher molecular weight for AAT-2 compared with AAT-1. AAT-1 appears to be more anionic than AAT-2, which was suggested by the anion exchange chromatography. SDS-PAGE showed a similar sub-unit molecular weight for both isoenzymes. The optimum pH (between 8,0 and 9.0) and temperature ($60-65^{\circ}C$) were similar for both isoenzymes. In the temperature range of $45-65^{\circ}C$, AAT-2 has higher thermostability than AAT-1. Both isoenzymes showed a high affinity for keto-acid substrates, as well as a higher affinity to aspartate than glutamate. Manganese ions induced an increase in both AAT isoenzymes activities, but no cooperative effect was detected. Among the inhibitors tested, hydroxylamine affected both isoenzymes activity by an irreversible inhibition mechanism.

Dynamics of hospitalizations and in-hospital deaths from COVID-19 in northeast Brazil: a retrospective analysis based on the circulation of SARS-CoV-2 variants and vaccination coverage

Martins-Filho Paulo Ricardo,de Souza Araújo Adriano Antunes,Quintans-Júnior Lucindo José,Soares Bárbara dos Santos,Barboza Waneska de Souza,Cavalcante Taise Ferreira,Santos Victor Santana 한국역학회 2022 Epidemiology and Health Vol.44 No.-

This study investigated the dynamics of hospitalizations and in-hospital deaths from coronavirus disease 2019 (COVID-19) throughout the pandemic in northeast Brazil, the Brazilian region with the worst socioeconomic indicators. In total, 141,445 cases, 8,213 hospital admissions, and 1,644 in-hospital deaths from COVID-19 were registered from March 14, 2020 to February 5, 2022. The overall rates of hospitalization and in-hospital deaths were 5.8% and 20.0%, respectively. The hospitalization and death rates significantly decreased over time, which may have been related to progress in vaccination. During the spread of the Gamma variant (January to June 2021), most hospitalized individuals were young adults, and approximately 40% of deaths occurred in this age group. During the predominance of Delta (July to December 2021), over 75% of deaths occurred among the elderly and unvaccinated or partially vaccinated individuals. This rate decreased to 42.3% during the transmission of the Omicron variant (January to February 2022), during which 34.6% of deaths were recorded among fully vaccinated individuals (2 doses) and 23.1% among those who received full vaccination and a booster. The Omicron-driven third wave was associated with a rise in the proportion of deaths among vaccinated individuals, especially among those who had not received a booster dose.

Design and Analysis of a Multiband UWB-MIMO Antenna for 5-10 GHz Application

Martins Ezuma(마틴즈 에즈마),Beom-Hun Kim(김범훈),June-Buem Park(박준범),Jae-Abung Pyun(변재영) 조선대학교 IT연구소 2016 정보기술융합공학논문지 Vol.6 No.2

Food toxicity assessment of selected canned foods in Nigeria

Martins O. Ainerua,Nosakhare Erhunmwunse,Isioma Tongo,Lawrence Ezemonye 한국독성학회 2020 Toxicological Research Vol.36 No.1

Food toxicity assessment was made for frequently consumed canned foods in Nigeria in order to estimate potential human health risks associated with their consumption. Levels of heavy metals (Pb, Cd, As, Fe, Mn and Zn), Nitrate and Nitrite, pH and salt were assessed in randomly purchased samples from groceries stores to represent what is readily available on the market. Nitrates and nitrites were assessed using a Perkin-Elmer spectrophotometer while heavy metal levels were determined using Atomic absorption spectrophotometer. Human health risk was estimated using standard indices; estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI) and dietary exposure (DE). Results showed varying concentrations of nitrates, nitrites, heavy metals, in all the canned food categories but the level of salt and pH seemed constant. Nitrate, Fe and Cd in all the canned food categories exceeded recommended limit set by EU. Health risk estimations showed EDI values for Cd in all the canned food categories above the tolerable daily intake, while DE for Fe in canned sweet corn, Fe, Zn and Pb in canned beans/peas had values above recommended limits. THQ values for all the canned foods were above 1 in the canned beans/peas while HI was above 1 in the canned fish category. The study revealed the potential for Cd toxicity and risk of non-carcinogenic health effects from canned beans/peas consumption. Constant monitoring of canned foods is therefore imperative considering the growing demand for canned products due to changing lifestyle.

Automated Synthesis of an Optimized 5.2㎓ Microstrip Antenna using Genetic Algorithm and an Accurate Transmission Line Model

Martins Chidozie Ezuma,Hui-Seon Gang,Jae-Young Pyun 한국정보기술학회 2016 한국정보기술학회논문지 Vol.14 No.3

This paper presents a computationally efficient approach for automating the process of synthesizing optimized microstrip antennas. The approach is used for designing an optimized 5.2㎓ microstrip antenna for wireless local area network (WLAN) applications. Indeed, the antenna is modeled as an equivalent circuit and an accurate transmission line technique is then used to analytically derive the input impedance of the target microstrip antenna when resonating at the fundamental TM01 mode. This input impedance is used to derive the fitness function for a robust genetic algorithm, which is to synthesize the optimized geometric parameters of the target microstrip antenna. The synthesized antenna is designed and simulated in the High Frequency Structural Simulator (HFSS) design environment, which is 3D EM simulation software. The plots of the reflection coefficient and the radiation patterns of the synthesized antenna are obtained in this environment. The simulation results show that the synthesized antenna has a good radiation property and resonates at the target frequency of 5.2㎓ with a return loss under -25㏈.

Characterization of Aspartate Aminotransferase Isoenzymes from Leaves of Lupinus albus L. cv Estoril

Martins, Maria Luisa Louro,Mourato, Miguel Pedro de Freitas Barbosa,Mendonca, Amarilis Paula alberti de varennes e 생화학분자생물학회 1989 BMB Reports Vol.35 No.2

Two aspartate azninotransferase (EC 2.6.1.1) isoenzymes (AAT-1 and AAT-2) from Lupines albus L. cv Estoril were separated, purified, and characterized. The molecular weight, pI value, optimum pH, optimum temperature, and thermodynamic parameters for thermal inactivation of both isaenzymes were abtained. Studies of the kinetic mechanism, and the kinetics of product inhibition and high substrate concentration inhibition, were performed. The effect of some divalent ions and irreversible inhibitors on both AAT isoenzymes was also studied. Native PAGE showed a higher molecular weight for AAT 2 compared with AAT 1. AAT 1 appears to be more anionic than AAT 2, which was suggested by the anion exchange chromatography SDS-PAGE showed a similar sub-unit molecular weight for both isoenzymes. The optimum pH (between 8.0 and 9.0) and temperature (60-65℃) were similar far both isoenzymes. In the temperature range of 45-65℃, AAT-2 has higher thermostability than AAT-1. Both isoenzymes showed a high affinity for keto-acid substrates, as well as a higher affinity to aspartate than glutamate. Manganese ions induced an increase in both AAT isoenzymes activities, but no cooperative effect was detected. Among the inhibitors tested, hydroxylamine affected both isoenzymes activity by an irreversible inhibition mechanism.

Wound dressing using graphene quantum dots: a proof of concept

Martins Vanessa Gonzalez Ferreira Caminha,Alencar Luciana Magalhaes Rebelo,Souza Pedro Filho Noronha,Lorentino Carolinne Margot Albanez,Frota Heloisa Freire,dos Santos Andre Luis Souza,Gemini-Piperni 한국약제학회 2023 Journal of Pharmaceutical Investigation Vol.53 No.2

Purpose The costs and complexity related to effective wound healing treatment are immense. The number of multifactorial aspects related to the treatment of wounds (inflammation, infection, and many others) implies a complex multi-therapeutic approach involving various procedures, including medication and surgery. Regarding medication, there are only a few options, especially to treat chronic wounds. Recently graphene quantum dots have been applied for their potent antimicrobial properties as well as their significant tissue remodeling properties. In this study, we developed a formulation based on graphene quantum dots in the form of as a dry powder for wound healing. Methods Graphene quantum dots were produced by top-down technique using graphite as matrix, and fully characterized by Raman spectroscopy, atomic force microscopy, and X-ray diffractometry. The dry powder formulation was produced under aseptic conditions and evaluated in vitro and in vivo. Results The results showed that the formulation improved the healing process in both: in vitro and in vivo, with good adherence, healing time and tissue reconstruction. Finally, the results demonstrated that dry powder was very effective against P. aeruginosa, S. epidermidis, C. albicans and C. tropicalis, representing an improvementfor wound healing purposes. Conclusion The data corroborated the use of the dry powder formulation using graphene quantum dots as matrix as wound dressing, expanding the use of graphene quantum in the biomedical field.

Hand-held dental X-ray device: Attention to correct use

Martins Guilherme Ceschia,Rocha Thaíza Gonçalves,de Lima Azeredo Thaís,de Castro Domingos Andréa,Visconti Maria Augusta,Villoria Eduardo Murad 대한영상치의학회 2023 Imaging Science in Dentistry Vol.53 No.3

Women in the Igbo Culture: Extrapolations from Nsukka, South-Eastern Nigeria

Martins N. Okoro 숙명여자대학교 아시아여성연구원 2022 Asian Women Vol.38 No.1

The study documents all the key aspects through which the cultural representation of the Nsukka town women is constructed. It seeks to investigate women’s involvement and participation in the cultural enactment of festivals, title-taking ceremonies, burials and funerals, marriage ceremonies, postpartum care, and conflict resolution, relying on materials from literature, ethnographic data, studies involving participant observation, and interview sessions with natives possessing a sufficient knowledge of culture and tradition. Data collected were examined using historical descriptive and analytical methods and the study is anchored in Jones Lewis’s theory of feminism which, among other criticisms, questions how much of our culture is based on patriarchal assumptions. The study found that even though women are subjugated in certain aspects of life, their involvement and participation in the enactments of cultural events and conflict management in Nsukka town give them some sense of belonging and that, without their involvement, such cultural and traditional events would not take place and their essence would be lost. These counter claim that men are often considered the drivers of cultural activities and as such belong to the public domain while women are confined purely to private life and domestic activities. The study is helpful in understanding the implications of women’s involvement and participation in the enactments of culture and tradition in Nsukka town.