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㏈.

Design and evaluation of a head-mounted display for immersive 3D teleoperation of field robots

Martins, Henrique,Oakley, Ian,Ventura, Rodrigo Cambridge University Press 2015 Robotica Vol.33 No.10

<B>SUMMARY</B><P>This paper describes and evaluates the use of a head-mounted display (HMD) for the teleoperation of a field robot. The HMD presents a pair of video streams to the operator (one to each eye) originating from a pair of stereo cameras located on the front of the robot, thus providing him/her with a sense of depth (stereopsis). A tracker on the HMD captures 3-DOF head orientation data which is then used for adjusting the camera orientation by moving the robot and/or the camera position accordingly, and rotating the displayed images to compensate for the operator's head rotation. This approach was implemented in a search and rescue robot (RAPOSA), and it was empirically validated in a series of short user studies. This evaluation involved four experiments covering two-dimensional perception, depth perception, scene perception, and performing a search and rescue task in a controlled scenario. The stereoscopic display and head tracking are shown to afford a number of performance benefits. However, one experiment also revealed that controlling robot orientation with yaw input from the head tracker negatively influenced task completion time. A possible explanation is a mismatch between the abilities of the robot and the human operator. This aside, the studies indicated that the use of an HMD to create a stereoscopic visualization of the camera feeds from a mobile robot enhanced the perception of cues in a static three-dimensional environment and also that such benefits transferred to simulated field scenarios in the form of enhanced task completion times.</P>

Validation of 2D shock capturing flood models around a surcharging manhole

Martins, R.,Kesserwani, G.,Rubinato, M.,Lee, S.,Leandro, J.,Djordjević,, S.,Shucksmith, J. D. Informa UK (TaylorFrancis) 2017 Urban water journal Vol.14 No.9

<P>This work offers a detailed validation of finite volume (FV) flood models in the case where horizontal floodplain flow is affected by sewer surcharge flow via a manhole. The FV numerical solution of the 2D shallow water equations is considered based on two approximate Riemann solvers, HLLC and Roe, on both quadrilateral structured and triangular unstructured mesh-types. The models are validated against a high resolution experimental data-set obtained using a physical model of a sewer system linked to a floodplain via a manhole. It was verified that the sensitivity of the models is inversely proportional to the surcharged flow/surface inflow ratio, and therefore requires more calibration from the user especially when concerned with localised modelling of sewer-to-floodplain flow. Our findings provide novel evidence that shock capturing FV-based flood models are applicable to simulate localised sewer-to-floodplain flow interaction.</P>

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.

Miller Fisher Syndrome in Patients With Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Systematic Review

Martins-Filho Paulo Ricardo,Pereira de Andrade Ana Luiza,Pereira de Andrade Ana Júlia,Moura da Silva Maria Daniella,de Souza Araújo Adriano Antunes,Nunes Paula Santos,Santos Victor Santana,Ferreira Li 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.4

Background and Purpose Miller Fisher syndrome (MFS) is a subtype of Guillain-Barré syndrome characterized by the triad of ophthalmoparesis, areflexia, and ataxia. Although cases of MFS have been associated with severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2) infection, no studies have synthesized the clinical characteristics of patients with this condition. Methods In this rapid systematic review, we searched the PubMed database to identify studies on MFS associated with SARS-CoV-2 infection. Results This review identified 11 cases, of whom 3 were hospitalized with motor and/or sensory polyneuropathy as the first sign of SARS-CoV-2 infection. SARS-CoV-2 RNA was not detected in analyses of cerebrospinal fluid, suggesting a mechanism of immune-mediated injury rather than direct viral neurotropism. However, antiganglioside antibodies were found in only two of the nine patients tested. It is possible that target antigens other than gangliosides are involved in MFS associated with SARS-CoV-2 infection. Conclusions The present patients exhibited clinical improvement after being treated with intravenous immunoglobulin. Although rare, patients with SARS-CoV-2 infection may present neurological symptoms suggestive of MFS. Early recognition of the MFS clinical triad is essential for the timely initiation of treatment.

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

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.

Prevalence of SARS-CoV-2 infection among urban cleaning and solid waste management workers during transmission of the Omicron variant in Brazil

Martins-Filho Paulo Ricardo,dos Santos Joyce Thayane da Conceição,Rezende Márcia Santos,de Carvalho Fernanda Oliveira,dos Reis Érica Santos,Barboza Waneska de Souza,Cavalcante Taise Ferreira,dos Sant 한국역학회 2023 Epidemiology and Health Vol.45 No.-

This study estimated the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in urban cleaning and solid waste management workers during the transmission of the Omicron variant in one of the poorest regions of Brazil (the state of Sergipe). Nasopharyngeal swabs were collected from 494 workers, and the presence of SARS-CoV-2 RNA was tested by quantitative reverse-transcriptase polymerase chain reaction. Data on sociodemographic characteristics, comorbidities, vaccination status, mask use, and use of public transport to commute to the workplace were collected. The prevalence with a 95% confidence interval (CI) was calculated from the proportion of SARS-CoV-2 positive cases among the total number of individuals tested. The prevalence ratio (PR) with a 95% CI was the measure of association used to evaluate the relationship between SARS-CoV-2 infection and the exposure variables. The prevalence of SARS-CoV-2 infection was 22.5% (95% CI, 19.0%–26.4%). Individuals under the age of 40 had a higher prevalence of infection (PR=1.53; 95% CI, 1.03–2.30) as well as those who did not believe in the protective effect of vaccines (PR=1.78; 95% CI, 1.05–2.89). Our results indicate the need for better guidance on preventive measures against COVID-19 among urban cleaning and solid waste management workers.

A novel method of objectively detecting tooth ankylosis using cone-beam computed tomography: A laboratory study

Martins Luciano Augusto Cano,Brasil Danieli Moura,Freitas Deborah Queiroz,Oliveira Matheus L 대한영상치의학회 2023 Imaging Science in Dentistry Vol.53 No.1

Purpose: The aim of this study was to objectively detect simulated tooth ankylosis using a novel method involving cone-beam computed tomography (CBCT). Materials and Methods: Tooth ankylosis was simulated in single-rooted human permanent teeth, and CBCT scans were acquired at different current levels (5, 6.3, and 8 mA) and voxel sizes (0.08, 0.125, and 0.2). In axial reconstructions, a line of interest was perpendicularly placed over the periodontal ligament space of 21 ankylosed and 21 non-ankylosed regions, and the CBCT grey values of all voxels along the line of interest were plotted against their corresponding X-coordinates through a line graph to generate a profile. The image contrast was increased by 30% and 60% and the profile assessment was repeated. The internal area of the resulting parabolas was obtained from all images and compared between ankylosed and non-ankylosed regions under different contrast enhancement conditions, voxel sizes, and mA levels using multi-way analysis of variance with the Tukey post hoc test (α = 0.05). Results: The internal area of the parabolas of all non-ankylosed regions was significantly higher than that of the ankylosed regions (P<0.05). Contrast enhancement led to a significantly greater internal area of the parabolas of non- ankylosed regions (P<0.05). Overall, voxel size and mA did not significantly influence the internal area of the parabolas (P>0.05). Conclusion: The proposed novel method revealed a relevant degree of applicability in the detection of simulated tooth ankylosis; increased image contrast led to greater detectability.

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.