This article presents microneedles analyses where the design parameters studied included length and inner and outer diameter ranges. A mathematical model was also used to generalize outer and inner diameter ratios in the obtained ranges. Following this, the range of inner and outer diameters was completed by mechanical simulations, ranging from 30 μm to 134 μm as the inner diameter range and 208 μm to 250 μm as the outer diameter range. With these ranges, a mathematical model was made using fourth-order polynomial regressions with a correlation of 0.9993, ensuring a safety factor of four in which von Misses forces of the microneedle are around 17.931 MPa; the ANSYS software was used to analyze the mechanical behavior of the microneedles. In addition, the microneedle concept was made by 3D printing using a bio-compatible resin of class 1. The features presented by the microneedle designed in this study make it a promising option for implementation in a transdermal drug-delivery device.

Diabetes mellitus is an endocrine disorder that affects glucose metabolism, making the body unable to effectively use the insulin it produces. Transdermal drug delivery (TDD) has attracted strong interest from researchers, as it allows minimally invasive and painless insulin administration, showing advantages over conventional delivery methods. Systems composed of microneedles (MNs) assembled in a transdermal patch provide a unique route of administration, which is innovative with promising results. This paper presents the design of a transdermal patch composed of 25 microneedles manufactured with 3D printing by stereolithography with a class 1 biocompatible resin and a printing angle of 0°. Finite element analysis with ANSYS software is used to obtain the mechanical behavior of the microneedle (MN). The values obtained through the analysis were: a Von Misses stress of 18.057 MPa, a maximum deformation of $2.179\times {10}^{-3}$, and a safety factor of 4. Following this, through a flow simulation, we find that a pressure of 1.084 Pa and a fluid velocity of 4.800 $\frac{\mathrm{m}}{\mathrm{s}}$ were necessary to ensure a volumetric flow magnitude of $4.447\times {10}^{-5}\frac{{\mathrm{cm}}^3}{\mathrm{s}}$. Furthermore, the parameters found in this work are of great importance for the future implementation of a transdermal drug delivery device.

Background: Visual impairment (VI) significantly impacts quality of life, particularly in autonomous pedestrian navigation. Limitations in independent navigation lead to frustration, diminished confidence, and risks to bodily integrity for individuals with VI. In Colombia, the pilot country of this study, approximately 2 million people live with some form of visual disability. Globally, only 1 in 10 people requiring assistive devices have access to them, with factors such as deficient product design stemming from limited knowledge of user expectations, local needs, and environmental constraints, posing significant challenges, particularly in low- and middle-income countries. Objective: We aimed to evaluate the feasibility and limitations of applying the human-centered design (HCD) principles outlined by the International Organization for Standardization (ISO) 9241-210:2019 standard in assistive technology (AT) development for individuals with VI in Colombia. Methods: We developed a prototype navigation device using the HCD principles, emphasizing a thorough analysis of user needs and environmental contexts. The project leveraged multidisciplinary collaboration to address challenges associated with user engagement and design adaptability while managing legal and bureaucratic constraints. The navigation system integrates artificial intelligence algorithms, specifically developed by the research team as part of this work, to enhance its adaptability and responsiveness to diverse environments. The development process featured iterative prototyping cycles, incorporating user feedback at each stage, all within the boundaries of applicable regulatory frameworks. Results: The development and evaluation of the initial prototype highlighted both the feasibility and key limitations of applying the ISO 9241-210:2019 HCD principles in AT for individuals with VI in the Colombian context. The prototype met several user-defined expectations by prioritizing affordability; extended battery life; autonomy in internet-constrained environments; and improved ergonomics, concealability, aesthetics, and obstacle detection. These achievements demonstrated the potential of HCD to guide context-sensitive innovation. However, the process also revealed significant barriers: limited legal and procedural clarity for engaging users in design phases, difficulties navigating ethics committees, and a lack of practical guidance within the ISO standard itself. These constraints, compounded by challenges in interdisciplinary collaboration, limited the depth and adaptability of user involvement across development stages. Conclusions: Implementing HCD principles in AT development shows promise for creating effective and affordable solutions tailored to user needs and contexts. However, legislative and methodological barriers must be addressed to fully realize HCD’s potential. Future efforts should focus on aligning research methodologies with hardware and software development practices while integrating legislative frameworks to enhance the accessibility and effectiveness of AT innovations.

In military life, load carriage is an unavoidable part of field operations which is the reason why soldiers often make use of a military backpack. Infantry soldiers usually carry loads weighting more than 30% of their body weight. When the soldier carries a certain weight, his energy expenditure increases, which causes a reduction in performance. The transported load has a movement similar to the vertical displacement of the center of mass of the soldier while walking. This leads to a significant increase in the acceleration forces generated by the action of said load on the body which explains the increase in energy expenditure. The objective of this project was to develop a load carriage system that suspends the load and reduces its vertical displacement. Results show a reduction in both the vertical excursion of the load and in the total vertical ground reaction force when carrying a load with the developed prototype, with respect to the conventional military backpack.

Background: Work at heights is a high-risk occupational activity, with falls being a leading cause of fatal accidents in construction and industrial maintenance. Conventional safety training often does not fully prepare workers for real-world hazards. Immersive virtual reality (IVR) has emerged as a promising training tool, providing controlled and realistic simulations of hazardous scenarios. This hypothesis-generating pilot study evaluates the feasibility and effectiveness of IVR in enhancing practical skills, safety perception, and physiological responses during work-at-height training. Methods: This controlled trial will recruit first-time trainees from the National Learning Service (SENA) of Colombia. Participants will be assigned to an intervention group, receiving IVR training before field-based practical sessions, or a control group, receiving standard theoretical instruction. Outcomes include practical skill acquisition, ergonomic risk, cognitive performance, and physiological responses, including heart rate variability measured with validated devices. Assessments will be performed using standardized tools, and data will be analyzed with repeated-measures ANOVA and regression models to compare groups. Conclusions: By integrating practical, cognitive, ergonomic, and physiological measures, this study will provide evidence on whether IVR improves the effectiveness of work-at-height training beyond conventional methods. Findings may inform future strategies to enhance occupational safety training in high-risk work environments.