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- A 1.7-mW −92-dBm Sensitivity Low-IF Receiver in 0.13-um CMOS for Bluetooth LE ApplicationsPublication . Silva-Perreira, Marco.; Sousa, J. T. de; Freire, J. Costa; Vaz, J. CaldinhasThis paper presents a 1.7-mW low-intermediate-frequency receiver design for Bluetooth low-energy (BLE) applications. The design exploits particular aspects of BLE, such as the relaxed in-band interference characteristics, more precisely the C/I1 MHz, and the relatively high-frequency-shift keying modulation index, to deliver a high level of energy efficiency and simplicity to the receiver baseband architecture. Reliable quadrature signals are generated in the RF signal path without consuming energy, which is supported by an inverter-based low-noise amplifier (LNA) that achieves high gain and low noise figure under low-power budgets. A small-signal analysis of low-power inverter-based LNAs is presented offering simple design equations. Seeking an affordable solution, the fabricated prototype is fully integrated into an earlier generation CMOS technology node (0.13 μm), occupying a silicon area smaller than 0.7 mm2. The receiver achieves a sensitivity level of -92 dBm while consuming 1.41 mA from a 1.2-V supply.
- The 2018 periodontitis case definition improves accuracy performance of full-mouth partial diagnostic protocolsPublication . Botelho, João; Machado, Vanessa; Proença, Luís; Mendes, José JoãoWe aimed to compare the accuracy performance of the new 2018 periodontitis case definition by the European Federation of Periodontology (EFP)/ American Association of Periodontology (AAP) with Centers for Disease Control (CDC)/AAP 2012 in full-mouth partial recording protocols (PRP). Retrospective data from NHANES 2011-2012 and 2013-2014 were analyzed. For each case definition, full-mouth diagnostic was defined as the reference standard. Patients were diagnosed for the presence of periodontitis and staging for each PRP. Sensitivity, specificity, accuracy and precision, through several indicators, were determined. Performance measurement was assessed through binary and multiclass ROC/AUC analyses. Our performance analysis shows that the new 2018 classification outperforms the 2012 classification regarding the diagnosis and staging of periodontitis on full-mouth PRPs. This recent case definition has strengthened the utility of PRPs and its improvements certainly explain the observed findings. Also, our findings contribute to the reliability of PRPs and its use in future worldwide epidemiological surveys.
- 3D assessment of mandibular buccal shelf geometry for optimal micro-implant placement site in Portuguese individuals : a retrospective cone-beam computed tomography studyPublication . Borga, Joana; Bugaighis, Iman; Proença, Luís; Pereira, François Durand; Costa, Helder Nunes; Pereira, Pedro MarianoObjectives: To determine the most favourable Micro-Implant (MI) insertion site along the mandibular buccal shelf (MBS), using Cone Beam Computed Tomography (CBCT). Methods: This retrospective study assessed CBCT scans from 90 Portuguese patients (32 males and 58 females, aged 14 to 40 years). Paired MBS sites were determined. Comparative and correlation analyses were performed at p < 0.05. Results: A significant increase in MBS width was observed from the mesial to the distal direction (p < 0.001). Conversely, both the MBS steepness and cortical bone thickness significantly decreased from mesial to distal (p < 0.001). Significant negative correlation was also found between age and cortical bone thickness adjacent to the distobuccal cusp and distal tangent of both mandibular second molars (r ≤ −0.373, p ≤ 0.007). Furthermore, significant asymmetric differences were identified between the right and left MBS steepness as well as in the paired cortical bone thickness at the mesiobuccal cusp, buccal groove, and distobuccal cusp of the mandibular second molar (p ≤ 0.016). Conclusions: The results indicate that although there are sufficient MBS width and cortical bone thickness, vestibular to the mandibular second molar for MI insertion, the sites towards the distal root of the mandibular second molar are more favourable when considering MBS steepness. These findings are consistent for both sexes and apply to young and old individuals.
- 3D assessment of the relationship of the mandibular buccal shelf with the mandibular canal : a CBCT retrospective studyPublication . Feliciano, Jéssica; Pereira, Pedro Mariano; Proença, Luís; Borga, Joana; Bugaighis, ImanObjective: This study aimed to evaluate the micro-implant safest insertion site on the mandibular buccal shelf (MBS) without compromising the integrity of the mandibular canal (MC). Methods: This retrospective investigation included cone-beam computed tomography (CBCT) of 96 Portuguese patients (58 females and 38 males, average age of 25.5±10.2 years). Measurements were taken in four bilateral MBS sites buccal to the mandibular second molar; tangent to the distal surface (7D), distobuccal cusp tip (7CD), buccal groove (7S) and mesiobuccal cusp tip (7CM). The transversal MBS midpoint was also determined, and the maximum angulation from the transversal MBS midpoint was extracted relative to the true vertical plane. Subsequently, the distance from the MBS midpoint to the MC was calculated at this angulation. Descriptive and inferential statistical analyses were performed at p<0.05 Results: Significant correlations were observed among several variables and age, sex and bilateral asymmetry (p<0.05). The MBS transversal width and the distance from the MBS midpoint to the MC progressively increased in the posterior direction while the angulation decreased. Conclusion: The most appropriate micro-implant insertion location compared to the other MBS investigated sites, in the absence of impacted third molars, is adjacent to the distal surface of the second molar. This finding is consistent across all age groups, sexes, and insertion sides. However, due to the demonstrated variability, taking a CBCT scan prior to mini-implant insertion might be considered to minimize the risk of injury to the inferior alveolar nerve.
- 3D bioprinting of novel κ-carrageenan bioinks : an algae-derived polysaccharidePublication . Marques, Diana M. C.; Silva, João C.; Serro, Ana Paula; Cabral, Joaquim M. S.; Sanjuan-Alberte, Paola; Ferreira, Frederico C.Novel green materials not sourced from animals and with low environmental impact are becoming increasingly appealing for biomedical and cellular agriculture applications. Marine biomaterials are a rich source of structurally diverse compounds with various biological activities. Kappa-carrageenan (κ-c) is a potential candidate for tissue engineering applications due to its gelation properties, mechanical strength, and similar structural composition of glycosaminoglycans (GAGs), possessing several advantages when compared to other algae-based materials typically used in bioprinting such as alginate. For those reasons, this material was selected as the main polysaccharide component of the bioinks developed herein. In this work, pristine κ-carrageenan bioinks were successfully formulated for the first time and used to fabricate 3D scaffolds by bioprinting. Ink formulation and printing parameters were optimized, allowing for the manufacturing of complex 3D structures. Mechanical compression tests and dry weight determination revealed young’s modulus between 24.26 and 99.90 kPa and water contents above 97%. Biocompatibility assays, using a mouse fibroblast cell line, showed high cell viability and attachment. The bioprinted cells were spread throughout the scaffolds with cells exhibiting a typical fibroblast-like morphology similar to controls. The 3D bio-/printed structures remained stable under cell culture conditions for up to 11 days, preserving high cell viability values. Overall, we established a strategy to manufacture 3D bio-/printed scaffolds through the formulation of novel bioinks with potential applications in tissue engineering and cellular agriculture.
- 3D printing for dental applicationsPublication . Figueiredo-Pina, Célio Gabriel; Serro, Ana Paula
- Accuracy and interpretation of the acceleration from an inertial measurement unit when applied to the sprint performance of track and field athletesPublication . Miranda-Oliveira, Paulo; Branco, Marco; Fernandes, OrlandoIn this study, we aimed to assess sprinting using a developed instrument encompassing an inertial measurement unit (IMU) in order to analyze athlete performance during the sprint, as well as to determine the number of steps, ground contact time, flight time, and step time using a high-speed camera as a reference. Furthermore, we correlated the acceleration components (XYZ) and acceleration ratio with the performance achieved in each split time obtained using photocells. Six athletes (four males and two females) ran 40 m with the IMU placed on their fifth lumbar vertebra. The accuracy was measured through the mean error (standard deviation), correlation (r), and comparison tests. The device could identify 88% to 98% of the number of steps. The GCT, flight time, and step time had mean error rates of 0.000 (0.012) s, 0.010 (0.011) s, and 0.009 (0.009) s when compared with the high-speed camera, respectively. The step time showed a correlation rate of r = 0.793 (p = 0.001) with no statistical differences, being the only parameter with high accuracy. Additionally, we showed probable symmetries, and through linear regression models identified that higher velocities result in the maximum anteroposterior acceleration, mainly over 0–40 m. Our device based on a Wi-Fi connection can determine the step time with accuracy and can show asymmetries, making it essential for coaches and medical teams. A new feature of this study was that the IMUs allowed us to understand that anteroposterior acceleration is associated with the best performance during the 40 m sprint test.
- Accuracy of hidden Markov models in identifying alterations in movement patterns during biceps-curl weight-lifting exercisePublication . Peres, André B.; Espada, Mário C.; Santos, Fernando J.; Robalo, Ricardo A. M.; Dias, Amândio A. P.; Muñoz-Jiménez, Jesús; Sancassani, Andrei; Massini, Danilo A.; Pessôa Filho, Dalton M.This paper presents a comparison of mathematical and cinematic motion analysis regarding the accuracy of the detection of alterations in the patterns of positional sequence during biceps-curl lifting exercise. Two different methods, one with and one without metric data from the environment, were used to identify the changes. Ten volunteers performed a standing biceps-curl exercise with additional loads. A smartphone recorded their movements in the sagittal plane, providing information on joints and barbell sequential position changes during each lift attempt. An analysis of variance revealed significant differences in joint position (p < 0.05) among executions with three different loads. Hidden Markov models were trained with data from the bi-dimensional coordinates of the joint positional sequence to identify meaningful alteration with load increment. Tests of agreement tests between the results provided by the models with the environmental measurements, as well as those from image coordinates, were performed. The results demonstrated that it is possible to efficiently detect changes in the patterns of positional sequence with and without the necessity of measurement and/or environmental control, reaching an agreement of 86% between each other, and 100% and 86% for each respective method to the results of ANOVA. The method developed in this study illustrates the viability of smartphone camera use for identifying positional adjustments due to the inability to control limbs in an adequate range of motion with increasing load during a lifting task.
- Accuracy of inertial measurement units when applied to the countermovement jump of track and field athletesPublication . Miranda-Oliveira, Paulo; Branco, Marco; Fernandes, OrlandoIn this study, we aimed to assess the countermovement jump (CMJ) using a developed instrument encompassing an off-the-shelf Inertial Measurement Unit (IMU) in order to analyze performance during the contraction phase, as well as to determine the jump height and the modified reactive strength index (RSImod), using force plate (FP) data as reference. Eight athletes (six males and two females) performed CMJs with the IMU placed on their fifth lumbar vertebra. Accuracy was measured through mean error (standard deviation), correlation, and comparison tests. The results indicated high accuracy, high correlation (r), and no statistical differences between the IMU and the FP for contraction time (r = 0.902; ρ < 0.001), negative impulse phase time (r = 0.773; ρ < 0.001), flight time (r = 0.737; ρ < 0.001), jump time (r = 0.708; ρ < 0.001), RSImod (r = 0.725; ρ < 0.001), nor minimum force (r = 0.758; ρ < 0.001). However, the values related to the positive impulse phase did not have the expected accuracy, as we used different devices and positions. Our results demonstrated that our developed instrument could be utilized to identify the contraction phase, jump height, RSImod, and minimum force in the negative impulse phase with high accuracy, obtaining a signal similar to that of an FP. This information can help coaches and athletes with training monitoring and control, as the device has simpler applicability making it more systematic.
- Accuracy of panoramic radiograph for diagnosing periodontitis comparing to clinical examinationPublication . Machado, Vanessa; Proença, Luís; Morgado, Mariana; Mendes, José João; Botelho, JoãoIn this study, we explore the diagnostic accuracy of a Radiographic-based Periodontal Bone Loss (R-PBL) method as a screening tool for periodontitis, in the form of radiographic bone loss, under the 2018 case definition in comparison to the 2012 case definition. The analysis was based on 456 patients (253 females and 203 males), screened for periodontal status in the Study of Periodontal Health in Almada-Seixal (SoPHiAS) project and subjected to a panoramic dental X-ray. Patients were diagnosed for the presence of periodontitis following the 2018 and 2012 case definition. R-PBL classification was defined by alveolar bone loss and diagnosed as no periodontitis (≥80% remaining alveolar bone), mild to moderate periodontitis (66% to 79%), or severe periodontitis (<66%). We appraise the X-ray quality to look for the influence on the performance of R-PBL. Sensitivity, specificity, accuracy, and precision, through several indicators, were determined. Performance measurement was assessed through binary and multiclass Receiver operating characteristic/are under the curve (ROC/AUC) analyses. Our results show that the tested R-PBL method under the 2018 case definition is a reliable tool in periodontitis cases screening. This method does not replace clinical periodontal evaluation, but rather, it screens patients towards a definitive periodontitis diagnosis. These results will contribute to support the development of automated prediction systems towards periodontitis surveillance.