Search

Treatment of injuries to bone structure represents a significant economic burden for health care institutions and systems worldwide. The development of tissue engineering scaffolds has expanded to include the incorporation of nanotechnology platforms such as liposomes for the efficient delivery of chemotherapeutic agents. Pyrroloquinoline quinone (PQQ) is a naturally occurring quinone with antioxidant and tissue regenerative properties. In this study, the liposome-based encapsulation of PQQ was achieved by studying the effect of different downsizing methods and lipid compositions. Liposomal sonication produced stable vesicles of sizes

Recent developments in additive manufacturing (AM) have led to significant opportunities in the design and fabrication of implantable medical devices due to the advantages that AM offers compared to conventional manufacturing, such as high customizability, the ability to fabricate highly complex shapes, good dimensional accuracy, a clean build environment, and reduced material usage. The study of structural design optimization (SDO) involves techniques such as Topology Optimization (TO), Shape Optimization (SHO), and Size Optimization (SO) that determine specific parameters to achieve the best measurable performance in a defined design space under a given set of loads and constraints. Integration of SDO techniques with AM leads to utmost benefits in designing and fabricating optimized implantable medical devices with enhanced functional performance. Research and development of various lattice structures represents a powerful method for unleashing the full potential of additive manufacturing (AM) technologies in creating medical implants with improved surface roughness, biocompatibility, and mechanical properties. Furthermore, the integration of artificial intelligence (AI) and machine learning (ML) in structural optimization has expanded opportunities to improve device performance, adaptability, and durability. The review is meticulously divided into two main sections, reflecting the predictability of the implant’s internal structure: (a) unpredictable interior topology, which explores topology-based optimization techniques, and (b) predictable inner topology, concentrating on lattice structures. The analysis of the reviewed literature highlights a common focus on addressing issues such as stress shielding, osseointegration enhancement, customization to individual needs, programmable functionalities, and weight reduction in implant designs. It emphasizes significant advances in reducing stress shielding effects, promoting osseointegration, and facilitating personalized implant creation. The review provides a detailed classification of optimization methods, with each approach scrutinized for its unique contribution to overcoming specific challenges in medical implant design, thus leading to more advanced, effective, and patient-oriented implantable devices.

Biodegradable materials such as WE43 magnesium are of great interest for bone tissue engineering applications. This research paper presents a novel manufacturing methodology (i.e., Joining Stacking based Laser Micro-Spot Welding (JS-LMSW)) for produce tubular WE43 Magnesium scaffolds. The proposed methodology consists of laser-cut tailored geometries joined and stacked using laser micro-spot welding to form a porous structure (scaffold). The relationship between microstructure and mechanical properties of the manufactured WE43 magnesium scaffolds is summarized in this paper. Additionally, the manufactured scaffolds were dimensionally and morphologically characterized, and the obtained results are close to the designed values (relative errors of ∼ 1.04%, 0.93%, 0.83%, and 1.53% for length, width, height, and interconnected porosity, respectively). Compressive testing was conducted on the scaffolds for axial and transversal loading conditions and, micro-hardness was evaluated in the micro spot welds. The obtained results indicated that the developed WE43 magnesium scaffold features bone-like mechanical properties. The elastic modulus range of cancellous bone is between 0.01 and 0.90 GPa compared to WE43 magnesium scaffold́s elastic modulus between 0.07 and 0.41 GPa for transversal and axial conditions, respectively. Hardness results showed values between 74 HV and 80 HV in the fusion zone and heat-affected zone, respectively. This novel methodology opens a new path for the construction of complex geometries such as scaffolds.

Light-based bioprinter manufacturing technology is still prohibitively expensive for organizations that rely on accessing three-dimensional biological constructs for research and tissue engineering endeavors. Currently, most of the bioprinting systems are based on commercial-grade-based systems or modified DIY (do it yourself) extrusion apparatuses. However, to date, few examples of the adoption of low-cost equipment have been found for light-based bioprinters. The requirement of large volumes of bioinks, their associated cost, and the lack of information regarding the parameter selection have undermined the adoption of this technology. This paper showcases the retrofitting and assessing of a low-cost Light-Based 3D printing system for tissue engineering. To evaluate the potential of a proposed design, a manufacturability test for different features, machine parameters, and Gelatin Methacryloyl (GelMA) concentrations for 7.5% and 10% was performed. Furthermore, a case study of a previously seeded hydrogel with C2C12 cells was successfully implemented as a proof of concept. On the manufacturability test, deviational errors were found between 0.7% to 13.3% for layer exposure times of 15 and 20 s. Live/Dead and Actin-Dapi fluorescence assays after 5 days of culture showed promising results in the cell viability, elongation, and alignment of 3D bioprinted structures. The retrofitting of low-cost equipment has the potential to enable researchers to create high-resolution structures and three-dimensional in vitro models.

Products and assets are becoming increasingly “smart”, e.g., mechatronic, electronic, or cyber-physical. In the lack of fully reliable wireless solutions, extensive wiring and wire bundling into wire harnesses are needed. This has manufacturing implications, leading to increasingly complex wire harness assembly processes, where numerous components, connectors, and cables are assembled, connecting critical and non-critical electric and electronic systems in smart products and assets. Thus, wire harnesses demand is rapidly rising in most industries, requiring human or robotic work. Often, required work tasks are repetitive and physically demanding, while still needing people for quality reasons. An attractive solution would therefore be humans collaborating with robots. Unfortunately, there are very few scientific studies on automation solutions using collaborative robots (cobots) for wire harness assembly process tasks to increase process productivity and improve work ergonomics. Furthermore, wire harness assembly process tasks are presently carried out 90% manually in this industry, causing serious ergonomic problems for assembly workers who perform such tasks daily. The challenge is reducing the ergonomic risks currently present in many established wire harness assembly processes while improving production time and quality. This paper presents an early prototype and simulation to integrate a cobot into a wire harness assembly process, primarily for work ergonomic improvements. The use of a cobot is specifically proposed to reduce ergonomic risks for wire harness assembly workers. Two methodologies: RULA and JSI were used to evaluate the ergonomics of the task of cable tie collocation. The real-world case study results illustrate the validation of a cobot which significantly reduced non-ergonomic postures in the task of placing cable ties in the wire harnesses assembly process studied. An ergonomic analysis without the cobot (the actual process) was conducted, based on RULA and JSI methodologies, presenting the highest possible scores in both evaluations, which calls for urgent changes in the current wire harness assembly process task studied. Then, the same analysis was performed with the cobot, obtaining significant reductions in the ergonomic risks of the task at hand to acceptable values.

Laparoscopic surgery demands highly skilled surgeons. Traditionally, a surgeon’s knowledge is acquired by operating under a mentor-trainee method. In recent years, laparoscopic simulators have gained ground as tools in skill acquisition. Despite the wide range of laparoscopic simulators available, few provide objective feedback to the trainee. Those systems with quantitative feedback tend to be high-end solutions with limited availability due to cost. A modular smart trainer was developed, combining tool-tracking and force-using employing commercially available sensors. Additionally, a force training system based on polydimethylsiloxane (PDMS) phantoms for sample stiffness differentiation is presented. This prototype was tested with 39 subjects, between novices (13), intermediates (13), and experts (13), evaluating execution differences among groups in training exercises. The estimated cost is USD $200 (components only), not including laparoscopic instruments. The motion system was tested for noise reduction and position validation with a mean error of 0.94 mm. Grasping force approximation showed a correlation of 0.9975. Furthermore, differences in phantoms stiffness effectively reflected user manipulation. Subject groups showed significant differences in execution time, accumulated distance, and mean and maximum applied grasping force. Accurate information was obtained regarding motion and force. The developed force-sensing tool can easily be transferred to a clinical setting. Further work will consist on a validation of the simulator on a wider range of tasks and a larger sample of volunteers.

Circular Economy (CE) models are increasingly referenced in international fora and on many countries’ climate action agendas. This emphasis is associated with the international environmental and climate crisis. The case of the electronics industry remains particularly relevant, given its background in the use of CE models and its potential to enhance their use. This work focuses on consumer behavior regarding electronics products in Mexico. This is a largely under-researched topic not only in Mexico but also in Latin America. This study demonstrates that, by trying to extend the lifespan of their electronic products, consumers have awareness of product circularity. However, there is a lack of incentives to capitalize on this consumer interest, compounded by the limited participation of manufacturers and distributors. It is concluded that with a well-designed public policy, the electronics industry (including the mobile phone sector) in Mexico can move toward a CE model more rapidly. A stronger initiative for CE by design should be part of these policies, not only in Mexico but also internationally. The role of better eco-labelling in promoting consumers’ environmental awareness is essential. The lessons of this case study might be of interest to other countries as well.

Magnesium alloys are of increasing interest in the medical industry due to their biodegradability properties and better mechanical properties as compared to biodegradable polymers. Fiber laser cutting of AZ31 magnesium alloy tubes was carried out to study the effect of cutting conditions on wall surface roughness and back-wall dross. During the experiments, an argon gas chamber was adapted in order to avoid material reactivity with oxygen and thus better control the part quality. A surface response methodology was applied to identify the significance of pulse overlapping and pulse energy. Our results indicate minimum values of surface roughness (Ra < 0.7 μm) when the spot overlapping is higher than 50%. A back-wall dross range of 0.24% to 0.94% was established. In addition, a reduction in back-wall dross accumulations was obtained after blowing away the dross particles from inside the tube using an argon gas jet, reaching values of 0.21%. Laser cutting experimental models show a quadratic model for back-wall dross related with the interaction of the pulse energy, and a linear model dependent on pulse overlapping factor for surface roughness.

Laser cutting is a key technology for the medical devices industry, providing the flexibility, and precision for the processing of sheets, and tubes with high quality features. In this study, extensive experimentation was used to evaluate the effect of fiber laser micro-cutting parameters over average surface roughness ( R a ) and back wall dross ( D bw ) in AISI 316L stainless steel miniature tubes. A factorial design analysis was carried out to investigate the laser process parameters: pulse frequency, pulse width, peak power, cutting speed, and gas pressure. A real laser beam radius of 32.1 μm was fixed in all experiments. Through the appropriate combination of process parameters (i.e., high level of pulse overlapping factor, and pulse energy below 32 mJ) it was possible to achieve less than 1 μm in surface roughness at the edge of the laser-cut tube, and less than 3.5% dross deposits at the back wall of the miniature tube.

We assessed xurography and laser ablation for the manufacture of passive micromixers arrays to explore the scalability of unconventional manufacture technologies that could be implemented under the restrictions of the Point of Care for developing countries. In this work, we present a novel split-and-recombine (SAR) array design adapted for interfacing standardized dispensing (handheld micropipette) and sampling (microplate reader) equipment. The design was patterned and sealed from A4 sized vinyl sheets (polyvinyl chloride), employing low-cost disposable materials. Manufacture was evaluated measuring the dimensional error with stereoscopic and confocal microscopy. The micromixing efficiency was estimated using a machine vision system for passive driven infusion provided by micropippetting samples of dye and water. It was possible to employ rapid fabrication based on xurography to develop a four channel asymmetric split-and-recombine (ASAR) micromixer with mixing efficiencies ranging from 43% to 65%.

Background: The aim of this study was to identify barriers to physical activity among elderly Brazilian women of different socioeconomic status (SES). Methods: A focus-group approach was employed. Subjects were aged, on average, 69.9 years (±6.9; n = 25). SES was measured based on a structured interview and women were grouped according to SES classification. Content analysis was used to categorize mentions of barriers to physical activities followed by descriptive analysis of absolute and relative frequencies of similar reports. Results: Most common barriers among high-SES elderly women were those within "psychological, cognitive, and emotional" dimensions (33.8%) and "environmental" (29.2%). Among women from lower SES, barriers were inversely ranked, the highest prevalence was verified for environmental (33.8%) and "psychological, cognitive, and emotional" dimensions (25%). Conclusions: The results highlight that barriers perception varies according to women's SES, indicating that physical activity promotion strategies must address such differences. [ABSTRACT FROM AUTHOR]

Strategies to stir and mix reagents in microfluid devices have evolved concomitantly with advancements in manufacturing techniques and sensing. While there is a large array of reported designs to combine and homogenize liquids, most of the characterization has been focused on setups with two inlets and one outlet. While this configuration is helpful to directly evaluate the effects of features and parameters on the mixing degree, it does not portray the conditions for experiments that involve more than two substances required to be subsequently combined. In this work, we present a mixing characterization methodology based on particle tracking as an alternative to the most common approach to measure homogeneity using the standard deviation of pixel intensities from a grayscale image. The proposed algorithm is implemented on a free and open-source mobile application (MIQUOD) for Android devices, numerically tested on COMSOL Multiphysics, and experimentally tested on a bidimensional split and recombine micromixer and a three-dimensional micromixer with sinusoidal grooves for different Reynolds numbers and geometrical features for samples with fluids seeded with red, blue, and green microparticles. The application uses concentration field data and particle track data to evaluate up to eleven performance metrics. Furthermore, with the insights from the experimental and numerical data, a mixing index for particles (mp) is proposed to characterize mixing performance for scenarios with multiple input reagents.

In this paper, we characterized an assortment of photopolymers and stereolithography processes to produce 3D-printed molds and polydimethylsiloxane (PDMS) castings of micromixing devices. Once materials and processes were screened, the validation of the soft tooling approach in microfluidic devices was carried out through a case study. An asymmetric split-and-recombine device with different cross-sections was manufactured and tested under different regime conditions (10 < Re < 70). Mixing performances between 3% and 96% were obtained depending on the flow regime and the pitch-to-depth ratio. The study shows that 3D-printed soft tooling can provide other benefits such as multiple cross-sections and other potential layouts on a single mold.

Biocompatible and biodegradable membrane treatments for regeneration of bone are nowadays a promising solution in the medical field. Bioresorbable polymers are extensively used in membrane elaboration, where polycaprolactone (PCL) is used as base polymer. The goal of this work was to improve electrospun membranes’ biocompatibility and antibacterial properties by adding micro- and nanoparticles such as Ag, TiO2 and Na2Ti6O13. Micro/nanofiber morphologies of the obtained membranes were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and a tensile test. Also, for this study optical microscopy was used to observe DAPI-stained cells. Membranes of the different systems were electrospun to an average diameter of 1.02–1.76 μm. To evaluate the biological properties, cell viability was studied by growing NIH/3T3 cells on the microfibers. PCL/TiO2 strength was enhanced from 0.6 MPa to 6.3 MPa in comparison with PCL without particles. Antibacterial activity was observed in PCL/TiO2 and PCL/Na2Ti6O13 electrospun membranes using Staphylococcus aureus bacteria. Bioactivity of the membranes was confirmed with simulated body fluid (SBF) treatment. From this study, the ceramic particles TiO2 and Na2Ti6O13, combined with a PCL matrix with micro/nanoparticles, enhanced cell proliferation, adhesion and antibacterial properties. The electrospun composite with Na2Ti6O13 can be considered viable for tissue regenerative processes.

This work explores the viability of 3D printed intervertebral lumbar cages based on biocompatible polycarbonate (PC-ISO® material). Several design concepts are proposed for the generation of patient-specific intervertebral lumbar cages. The 3D printed material achieved compressive yield strength of 55 MPa under a specific combination of manufacturing parameters. The literature recommends a reference load of 4,000 N for design of intervertebral lumbar cages. Under compression testing conditions, the proposed design concepts withstand between 7,500 and 10,000 N of load before showing yielding. Although some stress concentration regions were found during analysis, the overall viability of the proposed design concepts was validated.

This work focuses on the formulation of a constitutive equation to predict Mullins and residual strain effects of buna-N, silicone, and neoprene rubber strings subjected to small transverse vibrations. The nonmonotone behavior exhibited by experimental data is captured by the proposed material model through the inclusion of a phenomenological non-monotonous softening function that depends on the strain intensity between loading and unloading cycles. It is shown that theoretical predictions compare well with uniaxial experimental data collected from transverse vibration tests.

This work focuses on the experimental characterization of suture material samples of MonoPlus, Monosyn, polyglycolic acid, polydioxanone 2–0, polydioxanone 4–0, poly(glycolide-co-epsilon-caprolactone), nylon, and polypropylene when subjected to cyclic loading and unloading conditions. It is found that all tested suture materials exhibit stress-softening and residual strain effects related to the microstructural material damage upon deformation from the natural, undistorted state of the virgin suture material. To predict experimental observations, a new constitutive material model that takes into account stress-softening and residual strain effects is developed. The basis of this model is the inclusion of a phenomenological nonmonotonous softening function that depends on the strain intensity between loading and unloading cycles. The theory is illustrated by modifying the non-Gaussian average-stretch, full-network model to capture stress-softening and residual strains by using pseudoelasticity concepts. It is shown that results obtained from theoretical simulations compare well with suture material experimental data.

Despite the copious amount of research on the design and operation of micromixers, there are few works regarding manufacture technology aimed at implementation beyond academic environments. This work evaluates the viability of xurography as a rapid fabrication tool for the development of ultra-low cost microfluidic technology for extreme Point-of-Care (POC) micromixing devices. By eschewing photolithographic processes and the bulkiness of pumping and enclosure systems for rapid fabrication and passively driven operation, xurography is introduced as a manufacturing alternative for asymmetric split and recombine (ASAR) micromixers. A T-micromixer design was used as a reference to assess the effects of different cutting conditions and materials on the geometric features of the resulting microdevices. Inspection by stereographic and confocal microscopy showed that it is possible to manufacture devices with less than 8% absolute dimensional error. Implementation of the manufacturing methodology in modified circular shape- based SAR microdevices (balanced and unbalanced configurations) showed that, despite the precision limitations of the xurographic process, it is possible to implement this methodology to produce functional micromixing devices. Mixing efficiency was evaluated numerically and experimentally at the outlet of the microdevices with performances up to 40%. Overall, the assessment encourages further research of xurography for the development of POC micromixers.

A response surface methodology (RSM) was performed to study the influence of spot overlapping and pulse energy on back wall dross and surface roughness for fiber laser cutting of AISI 316 L stainless steel minitubes. Three treatments were compared to expel molten material (argon gas, compressed air, and a control test). Our results indicated that back wall dross and dross height reduction is observed when argon gas or compressed air is used through tubes compared with the control test. Additionally, a higher value of spot overlap (87.49%) and a lower value of pulse energy (30.31 mJ) resulted as the optimal parameters to cut minitubes.

Objective: Summarize the effects of interventions designed to promote physical activity during elementary school recess in children between 5 and 10 years old. Effective school interventions for children can promote physical activity and healthy behaviors. Methods: PubMed, Scopus, Bireme, SciELO, Web of Science, PsychINFO, Proquest, Physical Education Index, Sports Discus, and Eric databases were included in the data search. Original intervention articles on physical activity that used regression methods, published between 2000 and 2019 in English, Portuguese and Spanish were analyzed. Analyses were performed in 2019. Outcomes were organized according to the direction of the association by independent variables. Ten articles were considered eligible for data extraction and evaluation. Results: Several strategies were used including playground markings, demarcation of physical activities zones, group activities, availability of sports equipment and facilities. Most of the studies were conducted in the United States. Recess periods ranged from 20–94 min per day and intervention time ranged from 6 weeks to 2 years. Recess duration and intervention effects were positively associated with physical activity. Gender (girls) and age (oldest) were negatively associated with physical activity during recess. Conclusions: Interventions based on modifications of school environment such as playground markings demarcation of physical activities zones, group activities, availability of sports equipment and facilities are cheap and cost-effective for increasing physical activity in school recess.

Community programs can facilitate the access of vulnerable subgroups to physical activity (PA). This study analyzed the relationship between sociodemographic characteristics, health conditions, public open spaces (POS) usage, and women’s PA. The 155 participants were assiduous in taking part in PA classes in POS in São José dos Pinhais, Brazil. The accelerometer-based PA measures identified four outcomes: (1) daily light-intensity PA (LPA), (2) daily moderate-to-vigorous intensity PA (MVPA), (3) LPA in POS, and (4) MVPA in POS. Linear regression, and the Durbin–Watson and Mann–Whitney U tests were used for data analysis in STATA software. The main results showed that the weekly frequency (β: 10.9, p < 0.01) and intensity of the main activity in the POS (β: 22.4, p < 0.05) were related to daily MVPA. Economic level and length of stay in the POS were positively related to the LPA performed (p < 0.05). Weekly frequency (β: 2.4, p < 0.01), length of stay (β: 11.0, p < 0.01), and intensity of PA practiced in the POS (β: 5.9, p < 0.05) showed a positive relationship with MVPA in the POS. In conclusion, there was a positive relationship between some analyzed variables and PA of different intensities, especially the consistent relationship between weekly frequency of POS usage and MVPA. Participation in structured PA classes in a community program can contribute to an increase of 47 min of daily MVPA.

RESUMO O objetivo deste estudo foi analisar a associação entre o padrão de utilização de espaços públicos abertos (EPA) e o nível de atividade física (AF) de intensidade moderada a vigorosa (AFMV) em São José dos Pinhais, Paraná. Sexo, faixa etária e AF foram identificados com o System for Observing Play and Recreation in Communities (SOPARC). A AFMV foi analisada considerando as categorias de sexo, local, dia da semana, horário e período. Foram realizadas 2.591 observações de pessoas e a proporção de AFMV foi de 35%. O sexo feminino apresentou associação positiva com a AFMV (OR: 1,57; IC95%: 1,32-1,86), enquanto a utilização dos EPA no final de semana (OR: 0,55; IC95%: 0,46-0,65) e no período da tarde apresentou associação inversa com o desfecho (OR: 0,57; IC95%: 0,48-0,67). Conclui-se que mulheres e aqueles que utilizam os locais durante a semana ou pela manhã apresentam maiores chances de praticarem AFMV.

Abstract Background The ability to ‘age in place’ is dependent on a range of inter-personal, social and built environment attributes, with the latter being a key area for potential intervention. There is an emerging body of evidence that indicates the type of built environment features that may best support age friendly communities, but there is a need to expand and consolidate this, while generating a better understanding of how on how research findings can be most effectively be translated in to policy and practice. Methods The study is based on two case study cities, Curtiba (Brazil) and Belfast (UK), which have highly contrasting physical, social and policy environments. The study deploys a mix methods approach, mirrored in each city. This includes the recruitment of 300 participants in each city to wear GPS and accelerometers, a survey capturing physical functioning and other personal attributes, as well as their perception of their local environment using NEWS-A. The study will also measure the built environments of the cities using GIS and develop a tool for auditing the routes used by participants around their neighbourhoods. The study seeks to comparatively map the policy actors and resources involved in healthy ageing in the two cities through interviews, focus groups and discourse analysis. Finally, the study has a significant knowledge exchange component, including the development of a tool to assess the capacities of both researchers and research users to maximise the impact of the research findings. Discussion The HULAP study has been designed and implemented by a multi-disciplinary team and integrates differing methodologies to purposefully impact on policy and practice on healthy ageing in high and low-middle income countries. It has particular strengths in its combination of objective and self-reported measures using validated tools and the integration of GPS, accelerometer and GIS data to provide a robust assessment of ‘spatial energetics’. The strong knowledge exchange strand means that the study is expected to also contribute to our understanding of how to maximise research impact in this field and create effective evidence for linking older adult’s physical activity with the social, built and policy environments.

AZ31 magnesium coronary stents were studied through a manufacturing process chain involving laser cutting, acid pickling, and dip coating. The purpose of this study was to evaluate surface thickness and geometrical dimensions of stents after processing. Stents were dip coated in a solution using PCL with 1% of TiO _2 . Additionally, AZ31 coronary stents were dynamically tested using a degradation system based on peristaltic pumps. Our results indicate that coated stents degraded slower than AZ31 uncoated control stents. After 4 weeks of dynamic degradation under flowing Hank’s solution, coated stents lost only ∼9% in weight while uncoated stents lost ∼27% in weight. Stents were qualitatively evaluated after four weeks of degradation. Our results demonstrate the formation of micro-pores after one and two weeks of degradation for coated stents. Lamination was observed after three weeks of degradation, meanwhile, uncoated stents resulted with notches and an irregular surface caused by degradation.

ABSTRACT OBJECTIVE: To analyze the moderator effect of socioeconomic status in the association between the perceived environment and active commuting to school. METHODS: A total of 495 adolescents and their parents were interviewed. Perceived environment was operationalized in traffic and crime safety and assessed with the Neighborhood Environment Walkability Scale. Active commuting was self-reported by the adolescents, categorized in walking, bicycling or skating at least one time/week. Socioeconomic status was used as moderator effect, reported from adolescents' parents or guardians using Brazilian standardized socioeconomic status classification. Analyses were performed with Poisson regression on Stata 12.0. RESULTS: Prevalence of active commuting was 63%. Adolescents with low socioeconomic status who reported “it is easy to observe pedestrians and cyclists” were more likely to actively commute to school (PR = 1.18, 95%CI 1.03–1.13). Adolescents with low socioeconomic status whose parents or legal guardians reported positively to “being safe crossing the streets” had increased probability of active commuting to school (PR = 1.10, 95%CI 1.01–1.20), as well as those with high socioeconomic status with “perception of crime” were positively associated to the outcome (PR = 1.33, 95%CI 1.03–1.72). CONCLUSIONS: Socioeconomic status showed moderating effects in the association between the perceived environment and active commuting to school.

OBJECTIVE: To analyze the association between perceived neighborhood environment and physical activity (PA) in high school students from Curitiba (PR), Brazil. METHODS: A sample of 1,611 high school students from public schools was surveyed. The PA was assessed through questions, engaged for at least 20 minutes or 60 minutes. Perceptions on neighborhood environment were assessed through ten questions about neighborhood characteristics. Gender, age and number of cars in the household were self-reported and used as confounding variables. Absolute and relative frequencies were used in the sample, and associations were tested through adjusted logistic regressions for the confounding variables and stratified by gender (p < 0.05). RESULTS: The adjusted analyses showed that the variables "interesting things" among girls (OR = 1.77; 95%CI 1.05 - 2.96) and "there are places I like" (OR = 2.18; 95%CI 1.33 - 3.58) and "I see people my age", among boys, were associated with PA of at least 20 minutes/day once a week. Additionally, among boys, "I see people my age" was associated with 60-minute (OR = 1.68; 95%CI 1.15 - 2.45). Perceiving the neighborhood environment as "very good" was associated with higher chances of taking up PA among girls (OR = 1.92; 95%CI 1.15 - 3.22) and boys (OR = 3.13; 95%CI 1.97 - 4.97). CONCLUSION: A positive perception of the environment was associated to PA practice among boys and girls in this sample. The results suggest that some environmental characteristics which make neighborhoods more attractive could be related to PA among adolescents.

O objetivo deste estudo foi analisar a associação entre diferentes tipos e fontes de apoio social com a prática de atividade física exercida de adolescentes de Curitiba, Paraná, Brasil. Um inquérito de base escolar foi realizado com amostra representativa de adolescentes da rede pública de ensino (n = 1.469). Modelos de regressão múltipla foram utilizados para testar a associação entre a frequência semanal de apoio social recebido da família e dos amigos com a prática de atividade física. Entre os meninos, a companhia frequente da família (RP: 2,88; IC95%: 2,00-4,13) e a dos amigos (RP: 5,46; IC95%: 2,33-12,78), além do reforço positivo destes (RP: 1,81; IC95%: 1,18-2,77), apresentaram associação positiva com a atividade física. O convite esporádico da família apresentou associação negativa (RP: 0,66; IC95%: 0,46-1,14). Para as meninas, a companhia frequente da família (RP: 3,39; IC95%: 1,49-7,69) e a dos amigos (RP: 4,06; IC95%: 2,22-7,45) aumentam a probabilidade da realização de atividade física. Conclui-se que a companhia dos amigos é o tipo de apoio social mais importante para a prática de atividade física de adolescentes.

Este trabalho teve o objetivo de analisar a associação entre atividade física e autoeficácia em adolescentes. Realizou-se um estudo inquérito de base escolar com 1.698 adolescentes de Curitiba, Paraná, Brasil. A atividade física foi avaliada segundo frequência semanal (dias/semana) de prática de atividade física de intensidade moderada ou vigorosa. A autoeficácia foi analisada segundo a soma de uma escala composta por dez itens. A associação entre autoeficácia e atividade física foi testada pela regressão de Poisson (p < 0,05), estratificada por sexo. Entre os meninos, apenas elevada autoeficácia foi associada com todas as categorias de atividade física (p < 0,001), enquanto para as meninas níveis moderados e elevados de autoeficácia foram associados com todas as categorias de atividade física (p < 0,001). Conclui-se que a autoeficácia tem associação positiva com atividade física entre adolescentes, no entanto esta relação é mais consistente entre as meninas. Este é um aspecto importante para o delineamento de intervenções para a promoção de atividade física nesse grupo populacional.

O objetivo deste estudo foi verificar a associação entre a distância percebida até instalações de lazer (parques, praças, academias, ginásios e ciclovias) com a prática de atividade física e de exercícios em adolescentes de Curitiba, Paraná, Brasil. Estudo transversal realizado com amostra representativa de 1.474 adolescentes (14-18 anos), alunos da rede pública de ensino. Foi verificada associação inversa entre a distância > 31 minutos até academias e ginásios com a prática de atividade física nos meninos (RP = 0,78; IC95%: 0,69-0,88 e RP = 0,79; IC95%: 0,66-0,95, respectivamente). O número de instalações próximas da residência associou-se positivamente com a prática de atividade física nos meninos (RP = 1,18; IC95%: 1,04-1,34). Para as meninas, a distância > 31 minutos até um ginásio apresentou associação inversa com a prática de exercícios de força (RP = 0,93; IC95%: 0,87-0,99). Esses achados sugerem que a distância e a quantidade de instalações de lazer no bairro podem afetar o padrão de atividade física de adolescentes, sendo essa relação diferente entre os sexos.