Schwarzites and Triply Periodic Minimal Surfaces: From Pure Topology Mathematics to Macroscale Applications.

Schwarzites are porous (spongy-like) carbon allotropes with negative Gaussian curvatures. They are proposed by Mackay and Terrones inspired by the works of the German mathematician Hermann Schwarz on Triply-Periodic Minimal Surfaces (TPMS). This review presents and discusses the history of schwarzites and their place among curved carbon nanomaterials. The main works on schwarzites are summarized and are available in the literature. Their unique structural, electronic, thermal, and mechanical properties are discussed. Although the synthesis of carbon-based schwarzites remains elusive, recent advances in the synthesis of zeolite-templates nanomaterials have brought them closer to reality. Atomic-based models of schwarzites are translated into macroscale ones that are 3D-printed. These 3D-printed models are exploited in many real-world applications, including water remediation and biomedical ones.

Characterization of Microstructure, Optical Properties, and Mechanical Behavior of a Temporary 3D Printing Resin: Impact of Post-Curing Time.

The present study aimed to characterize the microstructure of a temporary 3D printing polymer-based composite material (Resilab Temp), evaluating its optical properties and mechanical behavior according to different post-curing times. For the analysis of the surface microstructure and establishment of the best printing pattern, samples in bar format following ISO 4049 (25 × 10 × 3 mm) were designed in CAD software (Rhinoceros 6.0), printed on a W3D printer (Wilcos), and light-cured in Anycubic Photon for different lengths of time (no post-curing, 16 min, 32 min, and 60 min). For the structural characterization, analyses were carried out using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The mechanical behavior of this polymer-based composite material was determined based on flexural strength tests and Knoop microhardness. Color and translucency analysis were performed using a spectrophotometer (VITA Easy Shade Advanced 4.0), which was then evaluated in CIELab, using gray, black, and white backgrounds. All analyses were performed immediately after making the samples and repeated after thermal aging over two thousand cycles (5-55 °C). The results obtained were statistically analyzed with a significance level of 5%. FT-IR analysis showed about a 46% degree of conversion on the surface and 37% in the center of the resin sample. The flexural strength was higher for the groups polymerized for 32 min and 1 h, while the Knoop microhardness did not show a statistical difference between the groups. Color and translucency analysis also did not show statistical differences between groups. According to all of the analyses carried out in this study, for the evaluated material, a post-polymerization time of 1 h should be suggested to improve the mechanical performance of 3D-printed devices.

Aumento do Rebordo Alveolar com Enxerto em Bloco Impresso Personalizado: Relato de Caso / Alveolar ridge augmentation with custom 3D-printed block graft: Case report

A utilização da tecnologia CAD/CAM (computer aided design/computer aided manufacturing) e 3D (tridimensional) para reconstruções alveolares na implantodontia permite o planejamento pré-operatório detalhado, o design do resultado desejado do enxerto e a avaliação virtual do resultado em relação à reconstrução protética. Este trabalho objetiva detalhar a técnica cirúrgica de enxerto ósseo sintético confeccionado por meio dessa tecnologia, seguido da instalação de implantes osseointegráveis e reabilitação protética em um defeito ósseo na mandíbula. Paciente masculino, 22 anos, compareceu à clínica por avulsão dos elementos 32, 31, 41 e 42 com significativa perda óssea vertical de rebordo alveolar. Devido à extensa perda óssea, realizou-se enxerto em bloco prototipado impresso. O escaneamento intraoral e os arquivos de imagem gerados foram enviados ao centro de planejamento virtual. Primeiramente, foi realizada a cirurgia para instalação do enxerto em bloco. Após o período de cicatrização, foi realizada cirurgia para instalação de dois implantes osseointegráveis. Esperado o período de três meses a partir da instalação dos implantes, foi realizada a confecção de próteses provisórias fixas sobre implantes a fim de realizar o condicionamento dos tecidos moles peri-implantares e o carregamento progressivo dos implantes. O aumento do rebordo alveolar através do uso de enxerto em bloco impresso personalizado apresentou-se como uma técnica com inúmeras vantagens, por não necessitar de sítio doador, reduzir tempo cirúrgico e apresentar perfeita adaptação do bloco ao defeito ósseo, resultando em menor morbidade pós-operatória. Essa técnica é uma indicação para casos de defeitos ósseos severos, visando a otimizar o resultado e a propiciar menor desconforto ao paciente.

The use of the technology CAD/CAM (computer aided design/computer aided manufacturing) and 3D (three dimensional) to alveolar reconstructions in implant dentistry allows detailed preoperative planning, the design of the desired grafting result, and the virtual evaluation of the result in relation to the prosthetic reconstruction. This paper aims to details the synthetic bone graft made through this technology, followed by the installation of osseointegrated implants and prosthetic rehabilitation in a bone imperfection in the jaw. A 22-year-old man attended the clinic due to a tooth avulsion of the four lower incisors with significant vertical bone loss of alveolar ridge. Because of the extensive bone loss, it was made a prototyped printed block graft. The intraoral scan and the generated image files were sent to the virtual planning center. First, it was necessary a surgery to install the block graft. After the healing process, it was made a surgery to put two osseointegrated implants. Three months later, temporary fixed prostheses on implants were made to conditioning the peri-implant soft tissues and the progressive loading of the implants. The increase of the alveolar ridge using personalized printed block graft was presented as a technique with numerous advantages, since it does not require a donor site, reduces the surgical time and presents perfect adaptation of the block to the bone imperfection, resulting in a less postoperative morbidity. This technique is indicated to cases of severe bone imperfections, aims to optimize results, and provide less discomfort to the patient.

3D wildlife skull models for wildlife veterinary training.

Wildlife veterinarians are necessary for zoonotic diseases and species loss management, and there is a rising interest to enroll at veterinary schools with the wish to work in zoo and wildlife medicine. However, teaching wildlife is challenging due to the difficulty faced by universities to work with wild animal specimens. The aim of the present was to evaluate the understanding efficiency of some anatomical and behavioral aspects using 3D printed models of four wildlife species skulls, the kinkaju (Potos flavus), the white-nosed coati (Nasua narica), the northern anteater (Tamandua mexicana), and the nine-banded armadillo (Dasypus novemcinctus). This study was performed on 85 third-year veterinary students, divided into an experimental and a control group, who used and not used 3D printed skulls, respectively. Results show that the experimental group shows higher scores, in three of the four variables evaluated, than the control group. Then, 3D wildlife printed skulls constitute a promising teaching tool for veterinary students. In fact, it may be as good as real skulls, since new 3D printers can print on high endurance and firmness stock with high accuracy at reduced costs. In this context, it is important to encourage its use for the training of new generations and keep professionals up to date.

Adhesion of biofilm, surface characteristics, and mechanical properties of antimicrobial denture base resin.

PURPOSE: This study incorporated the nanomaterial, nanostructured silver vanadate decorated with silver nanoparticles (AgVO3), into heat-cured resin (HT) at concentrations of 2.5%, 5%, and 10% and compared the adhesion of multispecies biofilms, surface characteristics, and mechanical properties with conventional heat-cured (HT 0%) and printed resins. MATERIALS AND METHODS: AgVO3 was incorporated in mass into HT powder. A denture base resin was used to obtain printed samples. Adhesion of a multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans was evaluated by colony-forming units per milliliter (CFU/mL) and metabolic activity. Wettability, roughness, and scanning electron microscopy (SEM) were used to assess the physical characteristics of the surface. The mechanical properties of flexural strength and elastic modulus were tested. RESULTS: HT 10%-AgVO3 showed efficacy against S. mutans; however, it favored C. albicans CFU/mL (P < .05). The printed resin showed a higher metabolically active biofilm than HT 0% (P < .05). There was no difference in wettability or roughness between groups (P > .05). Irregularities on the printed resin surface and pores in HT 5%-AgVO3 were observed by SEM. HT 0% showed the highest flexural strength, and the resins incorporated with AgVO3 had the highest elastic modulus (P < .05). CONCLUSION: The incorporation of 10% AgVO3 into heat-cured resin provided antimicrobial activity against S. mutans in a multispecies biofilm did not affect the roughness or wettability but reduced flexural strength and increased elastic modulus. Printed resin showed higher irregularity, an active biofilm, and lower flexural strength and elastic modulus than heat-cured resin.

Development and implementation of a significantly low-cost 3D bioprinter using recycled scrap material.

The field of 3D bioengineering proposes to effectively contribute to the manufacture of artificial multicellular organ/tissues and the understanding of complex cellular mechanisms. In this regard, 3D cell cultures comprise a promising bioengineering possibility for the alternative treatment of organ function loss, potentially improving patient life expectancies. Patients with end-stage disease, for example, could benefit from treatment until organ transplantation or even undergo organ function restoration. Currently, 3D bioprinters can produce tissues such as trachea cartilage or artificial skin. Most low-cost 3D bioprinters are built from fused deposition modeling 3D printer frames modified for the deposition of biologically compatible material, ranging between $13.000,00 and $300.000,00. Furthermore, the cost of consumables should also be considered as they, can range from $3,85 and $100.000,00 per gram, making biomaterials expensive, hindering bioprinting access. In this context, our report describes the first prototype of a significantly low-cost 3D bioprinter built from recycled scrap metal and off-the-shelf electronics. We demonstrate the functionalized process and methodology proof of concept and aim to test it in different biological tissue scaffolds in the future, using affordable materials and open-source methodologies, thus democratizing the state of the art of this technology.

Efeito de diferentes tratamentos de superfície na resistência ao cisalhamento entre uma resina nanohíbrida para impressão 3D e cimento resinoso / Effect of different surface treatments on the shear strength between a nanohybrid resin for 3D printing and resin cement

O objetivo deste trabalho foi avaliar a resistência de união entre uma resina nanohíbrida para impressão 3D com cimento resinoso após diferentes tratamentos de superfície e envelhecimento. Foram fabricados 120 blocos da resina nanohíbrida (Nanolab 3D, Wilcos do Brasil) em tamanhos de 10 x 8 x 2 mm, desenhados no software Rhinoceros 7 e depois impressos (W3D PRINT, Wilcos do Brasil) por método digital de processamento de luz (LCD). Foram produzidos também blocos de mesmo tamanho obtidos a partir de blocos de CAD/CAM de uma resina híbrida (Hybrid, Blue Dent), como grupo controle. Cinco tratamentos de superfície foram realizados nos blocos de resina: nenhum tratamento, condicionamento ácido com ácido fluorídrico, jateamento com Al3O2, imersão em monômero de metilmetacrilato (primer) e um grupo somando o jateamento com imersão em primer. Foram construídos cilindros (< 1 mm2) de cimento resinoso convencional dual sobre as superfícies tratadas com auxílio de matriz de silicone. A resistência de união foi medida usando uma máquina de ensaio universal e um teste de microcisalhamento com fio. Metade das amostras de cada grupo foram testadas sete dias após a cimentação, já a outra metade foi termociclada por 12.000 ciclos térmicos (5-55 ºC, 30 segundos cada) e ensaiadas a seguir. Os modos de falha foram analisados por um estereomicroscópio e imagens representativas foram realizadas com o auxílio do microscópio eletrônico de varredura. Após a análise inferencial com ANOVA 3-fatores foi possível observar que houve diferença estatisticamente significante tanto para os fatores material, tratamento de superfície e envelhecimento isoladamente, como para as interações entre eles. A resina híbrida de impressão mostrou maior resistência de união quando comparada com os blocos CAD/CAM. A ciclagem térmica aumentou a resistência de união das resinas impressas e diminuiu a mesma nos blocos de CAD/CAM. É possível concluir que a aplicação de silano é o melhor tratamento de superfície para as resinas de impressão 3D já que proporcionou bons valores de resistência de união e confiabilidade da interface adesiva. A resistência adesiva a longo prazo da resina híbrida de impressão 3D (Nanolab) é influenciada positivamente pelo envelhecimento (AU)

The objective of this work was to evaluate the bond strength between a nanohybrid resin for 3D printing with resin cement after different surface treatments and aging. 120 blocks of nanohybrid resin (Nanolab 3D, Wilcos do Brasil) were manufactured in sizes of 10 x 8 x 2 mm, designed in the Rhinoceros 7 software and then printed (W3D PRINT, Wilcos do Brasil) by digital light processing method (LCD ). Blocks of the same size obtained from CAD/CAM blocks of a hybrid resin (Hybrid, Blue Dent) were also produced as a control group. Five surface treatments were performed on the resin blocks: no treatment, acid etching with hydrofluoric acid, sandblasting with Al3O2, immersion in methylmethacrylate monomer (primer) and one group adding the sandblasting with immersion in primer. Cylinders (< 1 mm2) of conventional dual resin cement were built on the surfaces treated with the aid of a silicone matrix. Bond strength was measured using a universal testing machine and a wire microshear test. Half of the samples from each group were tested seven days after cementation, while the other half was thermocycled through 12,000 thermal cycles (5-55 ºC, 30 seconds each) and then tested. Failure modes were analyzed using a stereomicroscope and representative images were taken using a scanning electron microscope. After the inferential analysis with 3-way ANOVA, it was possible to observe that there was a statistically significant difference both for the material, surface treatment and aging factors alone, as well as for the interactions between them. The hybrid impression resin showed higher bond strength when compared to the CAD/CAM blocks. Thermal cycling increased the bond strength of printed resins and decreased it in CAD/CAM blocks. It is possible to conclude that silane application is the best surface treatment for 3D printing resins as it provided good bond strength values and reliability of the adhesive interface. The long-term adhesive strength of the 3D printing hybrid resin (Nanolab) is positively influenced by aging. (AU)

Reading digital- versus print-easy texts: a study with university students who prefer digital sources.

The transition from on-paper to on-screen reading seems to make it necessary to raise some considerations, as a greater attentional effort has been claimed for print texts than digital ones. Not surprisingly, most university students prefer this digital medium. This research aims to examine reading times by contextualizing this phenomenon into two processes: namely, word recognition and reading comprehension task on paper and on screen. Thus, two different tasks-counterbalanced into digital and print mediums-were carried out per each participant with a preference for a digital medium: a reading comprehension task (RCT) and a lexical decision task (LDT) after reading a specific story. Participants were slower reading print texts and no statistically significant differences were found in RCT accuracy. This result suggests that the task required more cognitive resources under the print medium for those with a worse comprehension performance in reading, and a more conservative pattern in digital RCT for those with a better performance.

3D-printed resins for provisional dental restorations: Comparison of mechanical and biological properties.

OBJECTIVES: To characterize the mechanical and biological properties of three commercially available resins, which are currently used for provisional restorations and to compare them to an experimental resin intended for definitive fixed dental prostheses. MATERIALS AND METHODS: Three commercially available resins: Crowntec (CT, Saremco), Temporary C&B (FL, Formlabs), C&B MFH (ND, Nextdent), and the experimental resin: Permanent Bridge (PB, Saremco) were printed and subjected to biaxial flexural strength test, finite element analysis, Weibull analysis, scanning electron microscopy, cell proliferation, immunohistochemistry and cytotoxicity assays. Samples from CT, PB, and ND were provided directly from the manufacturers ensuring ideal workflow. FL was printed using the workflow as recommended by the manufacturer, using a Formlabs 2 printer and their post-processing units Form Wash and Form Cure. RESULTS: From the tested resins, PB yielded the best overall results in terms of mechanical properties. Cell proliferation and cytotoxicity did not show any significant differences among materials. PB showed higher values for probability of survival predictions (35%) when subjected to 250 MPa loads, whereas the other materials did not reach 10%. SIGNIFICANCE: Despite mechanical differences between the evaluated materials, the outcomes suggest that 3D printed provisional resins may be used in clinical settings, following the manufacturers indications. New materials intended for long-term use, such as the PB resin, yielded higher mechanical properties compared to the other materials. Alternative printing and post-processing methods have not yet been evaluated and should be avoided until further literature is available. CLINICAL SIGNIFICANCE: 3D printed resins for provisional restorations have become popular with the emergence of new technologies. In this study, we evaluated three different commercially available resins for provisional restorations and one new experimental resin. The results from this study indicate that commercially available resins could be used in clinical settings under certain conditions and limited periods of time. Following the manufacturers protocols is of paramount importance to not compromise these properties.

Reading digital- versus print-easy texts: a study with university students who prefer digital sources

The transition from on-paper to on-screen reading seems to make it necessary to raise some considerations, as a greater attentional efort has been claimed for print texts than digital ones. Not surprisingly, most university students prefer this digital medium. This research aims to examine reading times by contextualizing this phenomenon into two processes: namely, word recognition and reading comprehension task on paper and on screen. Thus, two diferent tasks­counterbalanced into digital and print mediums­were carried out per each participant with a preference for a digital medium: a reading comprehension task (RCT) and a lexical decision task (LDT) after reading a specifc story. Participants were slower reading print texts and no statistically signifcant diferences were found in RCT accuracy. This result suggests that the task required more cognitive resources under the print medium for those with a worse comprehension performance in reading, and a more conservative pattern in digital RCT for those with a better performance.

Gender representation in food and beverage print advertisements found in corner stores around schools in Peru and Guatemala.

OBJECTIVE: The objective of this study is to assess gender representation in food and beverage print advertisements. RESULTS: The study follows a quantitative descriptive approach. Using a content analysis technique, we assessed the gender representation in 200 food and beverage print advertisements found in corner stores located in four areas around schools in Lima, Peru, and Guatemala City, Guatemala (100 advertisements per country). A total of 36% of the print advertisements exhibited a male main character for the case of Guatemala, while in Peru 14% of the print advertisements presented a male main character. Furthermore, in Guatemala, 22% of the main characters were male animated characters. Moreover, 27% of the print advertisements in Guatemala and 17%, in Peru were visually male-oriented. Overall, male characters appeared alongside sports references and in varied settings, whereas female characters were usually holding or consuming the product. In conclusion, although the majority of variables used to assess the representation of gender in food and beverage print advertisements were gender-neutral, those showing gender representation were mostly male-oriented. Despite its limited findings, the study provides evidence for the formulation of public policies and educational content aimed to protect children's and adolescents' health from the effects of food marketing.

Lip print: a humanitarian forensic action / Huella labial: una acción forense humanitaria

ABSTRACT Introduction: forensic science involves diverse scientific disciplines that apply their particular expertise to the legal and judicial system. However, in the last decades this science has been linked to humanitarian actions and human rights proceedings. Forensic dentistry plays a vital role in personal identification. The lip print analysis is a relatively a simple procedure used in this discipline. It consists of patterns evaluation of cracks in the elevations and depressions on the labial mucosa. The aim of this study was to determine the lip print patterns of a southern Colombian population in order to add evidence of preconditions for forensic issues as part of a humanitarian forensic action. Methods: a total of 384 participants ≥ 35 years old were included in this study. The lip prints were analyzed through Suzuki and Tsuchihashi's classification in order to identify the predominant lip prints in males and females. Descriptive analysis was used to determine the sample characteristics and a χ2 test was performed to analyze independence according to sex variable for these categorical data. Results: the analyses showed that Type I and I' together were the most commonly lip prints seen in this sample, followed by Type II. There were not statistical differences between males and females. Conclusions: the evaluation of lip prints is a cost-effective method, and it could be an alternative in developing countries, especially in those that address massive violations of human rights.

RESUMEN Introducción: la ciencia forense involucra diversas disciplinas científicas que aplican su experiencia particular al ámbito legal y judicial. Sin embargo, en las últimas décadas esta ciencia se ha relacionado con acciones humanitarias y procesos de derechos humanos. La odontología forense juega un papel vital en la identificación personal. El análisis de la huella labial es un procedimiento relativamente sencillo utilizado en esta disciplina. Éste consiste en la evaluación de patrones de fisuras en elevaciones y depresiones de la mucosa labial. El objetivo de este estudio fue determinar patrones de huella labial en una población del sur de Colombia, con el fin de agregar evidencia de precondiciones para problemas forenses como parte de una acción forense humanitaria. Métodos: en este estudio se incluyó un total de 384 participantes ≥ 35 años. Las huellas labiales se analizaron mediante la clasificación de Suzuki y Tsuchihashi para identificar el predominio en hombres y mujeres. Se utilizó un análisis descriptivo para identificar las características de la muestra y se realizó una prueba de χ2 para analizar la independencia en la variable sexo para estos datos categóricos. Resultados: los análisis mostraron que los Tipos I y I' en conjunto fueron las huellas labiales más comunes que se observaron, seguidas del Tipo II. No existieron diferencias estadísticas entre hombres y mujeres. Conclusiones: la evaluación de las huellas labiales es un método económico y podría ser una alternativa en países en desarrollo, especialmente en aquellos que sustentan violaciones masivas de derechos humanos.

Data on gender representation in food and beverage print advertisements found in corner stores from Guatemala and Peru.

OBJECTIVES: Data on gender representation in food and beverage advertisements may allow for a better understanding of how the food industry is targeting different audiences based on gender. Nonetheless, scant research on food and beverage print advertising with a gender approach has been conducted. Therefore, we sought to assess the prevalence of gender focus in print advertisements found inside corner stores in two cities: Guatemala City, Guatemala, and Lima, Peru. DATA DESCRIPTION: We developed two complementary datasets as part of the study: (1) a dataset of digital photographs of 200 food and beverage print advertisements found in corner stores located near schools (100 ads per country selected according to criteria such as product type, image quality, and uniqueness); (2) a quantitative dataset with data of the content analysis of these photographs. We employed 19 variables to record the general information and gender assessment of the ads. These datasets should allow scholars and public officials to identify gender-specific marketing strategies of the food industry that might impact children's and adolescents' nutrition differently.

Low-cost Gent type sampler constructed for urban atmospheric aerosol sampling.

The importance of studying the atmospheric pollution due to its effects on human health and other ecosystems, the inexistence of national production of equipment for air sample collection, and the high cost of the imported equipment (especially in developing countries) led the authors of the present work to construct a low-cost Gent type sampler. The construction of the sampler was carried out by combining low-cost materials with good mechanical strength (such as nylon 6.0), hydraulic piping PVC, and the use of a 3D printer. The innovation of the present work is the employment of a 3D printer using ABS polymer to create the grids that cannot be machined. In addition to the sampler, the system is composed of a vacuum pump, a gas meter, and a rotameter. The total cost of the sampling system amounted at about 1200 USD, and the cost of the manufactured Gent type sampler did not reach 100 USD. The results obtained while using this set for sampling atmospheric aerosol for a period of 11 months were compared with the mass concentration of PM10 obtained from the official environmental company, CETESB of São Paulo State, Brazil, showing good correlation with those from CETESB - which confirmed its effectiveness and suitability for use. The low cost, easy operation, and versatility of the built Gent type sampler enable its use for scientific and academic purposes. The equipment can be useful in environmental monitoring networks, in low-income regions, and as an instrument for environmental education used in universities.

Evaluación comparativa del pie plano en preescolares / Comparative assessment of flatfoot in preschool children

Resumen Introducción: El aumento o la reducción del arco longitudinal medial (ALM) puede afectar funciones esenciales en la biomecánica del pie, con repercusiones en la salud a largo plazo. El objetivo del presente estudio fue determinar la altura del ALM en niños de 3 a 6 años, a través de cinco métodos de análisis de huella para el diagnóstico de pie plano. Métodos: Se realizó un estudio observacional transversal con 367 niños de 3 a 6 años en un municipio del Estado de México. Se llevó a cabo una evaluación postural completa, plantoscopía por medio de la clasificación de Viladot y análisis de la huella en pedigrafía, calculando la altura del ALM mediante el ángulo de Clarke (AC), el índice de Staheli (IS), el índice de Chippaux-Smirak (ICS) y el ángulo gamma (Ag). Resultados: La prevalencia de pie plano utilizando el podoscopio fue del 57.7%. Mediante los ángulos y los índices, la prevalencia fue del 86.9% por IS, del 83.3% por ICS, del 95.9% por AC y del 22.3% por Ag. El Ag fue menos sensible para la detección de pie plano en comparación con el ICS, el IS y el AC. Conclusiones: De acuerdo con los resultados del presente estudio, se propone utilizar métodos de análisis de huella para el diagnóstico de pie plano, además de la valoración clásica con el podoscopio. Se recomienda incluir el diagnóstico y la vigilancia del pie plano en la consulta del niño sano, ya que desde edades tempranas puede detectarse la tendencia en la arquitectura podálica.

Abstract Background: The increase or reduction of the medial longitudinal arch (MLA) can affect essential functions in the foot biomechanics with long-term health consequences. The aim of the present study was to determine the height of the MLA in children from 3 to 6 years of age through five methods of footprint analysis for the diagnosis of flat foot. Methods: A cross-sectional observational study was conducted with 367 children aged 3 to 6 years in a municipality of the State of Mexico. We conducted a complete postural evaluation, plantoscopy by Viladot classification, and footprint analysis calculating the height of the ALM using the Clarke angle (CA), the Staheli index (SI), the Chippaux-Smirak index (CSM), and the gamma angle (gA). Results: The prevalence of flat feet using the podoscope was 57.7%. Through the angles and indexes, the prevalence was 86.9% for SI, 83.3% for CSI, 95.9% for CA, and 22.3% for gA. The gA was less sensitive for flat foot detection compared to CSI, SI and CA. Conclusions: Based on the present results, we propose that footprint analysis should be used for flat foot diagnosis besides the classic evaluation by podoscope. We recommend that flat foot diagnosis and surveillance should be included on in the consultation of the healthy child, as a trend for podalic architecture can be detected from early ages.

Comparative assessment of flatfoot in preschool children.

Background: The increase or reduction of the medial longitudinal arch (MLA) can affect essential functions in the foot biomechanics with long-term health consequences. The aim of the present study was to determine the height of the MLA in children from 3 to 6 years of age through five methods of footprint analysis for the diagnosis of flat foot. Methods: A cross-sectional observational study was conducted with 367 children aged 3 to 6 years in a municipality of the State of Mexico. We conducted a complete postural evaluation, plantoscopy by Viladot classification, and footprint analysis calculating the height of the ALM using the Clarke angle (CA), the Staheli index (SI), the Chippaux-Smirak index (CSM), and the gamma angle (gA). Results: The prevalence of flat feet using the podoscope was 57.7%. Through the angles and indexes, the prevalence was 86.9% for SI, 83.3% for CSI, 95.9% for CA, and 22.3% for gA. The gA was less sensitive for flat foot detection compared to CSI, SI and CA. Conclusions: Based on the present results, we propose that footprint analysis should be used for flat foot diagnosis besides the classic evaluation by podoscope. We recommend that flat foot diagnosis and surveillance should be included on in the consultation of the healthy child, as a trend for podalic architecture can be detected from early ages.

Background: Introducción">El aumento o la reducción del arco longitudinal medial (ALM) puede afectar funciones esenciales en la biomecánica del pie, con repercusiones en la salud a largo plazo. El objetivo del presente estudio fue determinar la altura del ALM en niños de 3 a 6 años, a través de cinco métodos de análisis de huella para el diagnóstico de pie plano. Métodos: Se realizó un estudio observacional transversal con 367 niños de 3 a 6 años en un municipio del Estado de México. Se llevó a cabo una evaluación postural completa, plantoscopía por medio de la clasificación de Viladot y análisis de la huella en pedigrafía, calculando la altura del ALM mediante el ángulo de Clarke (AC), el índice de Staheli (IS), el índice de Chippaux-Smirak (ICS) y el ángulo gamma (Ag). Resultados: La prevalencia de pie plano utilizando el podoscopio fue del 57.7%. Mediante los ángulos y los índices, la prevalencia fue del 86.9% por IS, del 83.3% por ICS, del 95.9% por AC y del 22.3% por Ag. El Ag fue menos sensible para la detección de pie plano en comparación con el ICS, el IS y el AC. Conclusiones: De acuerdo con los resultados del presente estudio, se propone utilizar métodos de análisis de huella para el diagnóstico de pie plano, además de la valoración clásica con el podoscopio. Se recomienda incluir el diagnóstico y la vigilancia del pie plano en la consulta del niño sano, ya que desde edades tempranas puede detectarse la tendencia en la arquitectura podálica.

A Low-Cost Calibration Method for Low-Cost MEMS Accelerometers Based on 3D Printing.

A ubiquitous sensor in embedded systems is the accelerometer, as it enables a range of applications. However, accelerometers experience nonlinearities in their outputs caused by error terms and axes misalignment. These errors are a major concern because, in applications such as navigations systems, they accumulate over time, degrading the position accuracy. Through a calibration procedure, the errors can be modeled and compensated. Many methods have been proposed; however, they require sophisticated equipment available only in laboratories, which makes them complex and expensive. In this article, a simple, practical, and low-cost calibration method is proposed. It uses a 3D printed polyhedron, benefiting from the popularisation and low-cost of 3D printing in the present day. Additionally, each polyhedron could hold as much as 14 sensors, which can be calibrated simultaneously. The method was performed with a low-cost sensor and it significantly reduced the root-mean-square error (RMSE) of the sensor output. The RMSE was compared with the reported in similar proposals, and our method resulted in higher performance. The proposal enables accelerometer calibration at low-cost, and anywhere and anytime, not only by experts in laboratories. Compensating the sensor's inherent errors thus increases the accuracy of its output.

Corpos tatuados: desejo de memória em completude / The human in Søren Kierkegaard and Viktor Frankl

Este artigo tem por objetivo apresentar vivências e significados de tatuagens a partir de narrativas de sujeitos adultos e idosos, com base em uma abordagem interdisciplinar. Questionamos: do culto ao corpo jovem, da exigência do labor do corpo adulto e da hipervigilância do corpo envelhecido, qual a significação do corpo tatuado em idades tão díspares? Realizamos uma descrição das narrativas de adultos e idosos com corpos tatuados a partir de um desenho de pesquisa qualitativa. Participaram da pesquisa 15 adultos com idades entre 22 e 67 anos em duas capitais brasileiras, Salvador e São Paulo. Entre as ideias conclusivas estão, de um lado, a tatuagem como metamorfose, liberdade e afirmação de si e, de outro, significações que ressaltam atatuagem como desejo de memória em completude, uma forma de fazer do corpo lugar de arquivo ou o próprio corpo como arquivo de memória completa.

This paper aims to present experiences and meanings of tattoos, from narratives of adult and elderly subjects, based on an interdisciplinary approach. We question: the cult of the young body, the demand of the labor of the adult body, and the hyper vigilance of the aged body, what is the meaning of the tattooed body in such disparate ages? We describe the narratives of adults and the elderly with tattooed bodies from a qualitative research design. Fifteen adults aged between 22 and 67 years participated in the research in two Brazilian capitals,Salvador and São Paulo. Among the concluding ideas are, on the one hand, the tattoo as a metamorphosis, freedom and affirmation of self and, on the other hand, meanings that emphasize the tattoo as a desire for memory in completeness, a way of making the body a place of archives, or the body itself as a full memory file.

Corpos tatuados: desejo de memória em completude / Tattooed bodies: desire for memory in completeness

Este artigo tem por objetivo apresentar vivências e significados de tatuagens a partir de narrativas de sujeitos adultos e idosos, com base em uma abordagem interdisciplinar. Questionamos: do culto ao corpo jovem, da exigência do labor do corpo adulto e da hipervigilância do corpo envelhecido, qual a significação do corpo tatuado em idades tão díspares? Realizamos uma descrição das narrativas de adultos e idosos com corpos tatuados a partir de um desenho de pesquisa qualitativa. Participaram da pesquisa 15 adultos com idades entre 22 e 67 anos em duas capitais brasileiras, Salvador e São Paulo. Entre as ideias conclusivas estão, de um lado, a tatuagem como metamorfose, liberdade e afirmação de si e, de outro, significações que ressaltam atatuagem como desejo de memória em completude, uma forma de fazer do corpo lugar de arquivo ou o próprio corpo como arquivo de memória completa.

This paper aims to present experiences and meanings of tattoos, from narratives of adult and elderly subjects, based on an interdisciplinary approach. We question: the cult of the young body, the demand of the labor of the adult body, and the hyper vigilance of the aged body, what is the meaning of the tattooed body in such disparate ages? We describe the narratives of adults and the elderly with tattooed bodies from a qualitative research design. Fifteen adults aged between 22 and 67 years participated in the research in two Brazilian capitals,Salvador and São Paulo. Among the concluding ideas are, on the one hand, the tattoo as a metamorphosis, freedom and affirmation of self and, on the other hand, meanings that emphasize the tattoo as a desire for memory in completeness, a way of making the body a place of archives, or the body itself as a full memory file.

Error Measurement Between Anatomical Porcine Spine, CT Images, and 3D Printing.

RATIONALE AND OBJECTIVES: 3D printers are increasingly used in medical applications such as surgical planning, creation of implants and prostheses, and medical education. For the creation of reliable 3D printed models of the vertebral column, processing must be performed on CT images. This processing must be assessed and validated so that any error of the printed model can be recognized and minimized. MATERIAL AND METHODS: In order to perform this validation, 10 CT scans of porcine lumbar spinal vertebra were used, which were then dissected and scanned again. CT image processing was performed to obtain a mesh and perform 3D printing. RESULTS: There was no statistical difference among the four different levels of vertebrae measurements (first CT images, second CT images, anatomical piece of porcine bone and 3D printing of porcine bone; One Way repeated measure ANOVA, F < F_crit, p value > α = 0.05). The Intraclass Correlation also revealed a mean intraclass correlation coefficient (3,1) = 0.9553, which describes the reliability of all four levels in addition to the reliability of the data between porcine samples subjected to different levels of measurement. This shows that the average error is less than 1 mm. CONCLUSIONS: The measurements of models created with 3D printers using the pipeline described in this paper have an average error of 0.60 mm with CT images and 0.73 mm with anatomical piece. Thus, 3D printed models accurately reflect in vivo bones and provide accurate 3D impressions to assist in surgical planning.