Publicaciones Científicas

Vitamin D has been widely studied for its implications on type 2 diabetes mellitus, a chronic condition characterized by insulin resistance, inflammation, and metabolic dysfunction. This review explores the molecular mechanisms underpinning vitamin D’s effects on glucose metabolism, inflammation, and adipogenesis, while assessing its potential clinical applications in type 2 diabetes. In its 1,25-dihydroxyvitamin D3 form, vitamin D modulates various metabolic processes, affecting proinflammatory cytokines and activating the AMPK pathway, inhibiting mTOR signaling, and promoting adipocyte differentiation. These effects enhance insulin sensitivity and reduce chronic inflammation, key contributors to metabolic dysfunction. In this context, the progression of prediabetes has been linked to vitamin D, which limits pathological progression and increases the likelihood of restoring a normal metabolic state, crucial in diabetes progression. Moreover, vitamin D has been reported to reduce the likelihood of developing diabetes by 15%, particularly in doses higher than the traditional recommendations for bone health. Despite promising evidence, discrepancies in study designs, serum vitamin D measurements, and population-specific factors highlight the need for standardized methodologies and personalized approaches. In conclusion, vitamin D has complementary therapeutic potential in treating type 2 diabetes, revealing gaps in research, such as optimal dosing and long-term effects across populations. Future studies should integrate molecular insights into clinical practice to optimize vitamin D’s impact on metabolic health.

Aim. This study aims to analyze the effects of virtual reality on engagement and fitness. Methods. This study adopted a mixed method. A total of 32 elite karate athletes from Palembang PGRI University (Indonesia) were recruited and allocated to the control (n = 15) or the virtual reality group (n = 17). Quantitative instruments used the Athlete Engagement Questionnaire to measure the level of engagement, and the hand grip test, standing board jump test, sit-and-reach test, 40-meter test, 4×9 m shuttle run test and bleep test to measure physical fitness. The instrument for qualitative research involved in-depth interviews. Results. This study showed several findings in the quantitative study. First, there was no difference in the value of engagement and fitness between the control and virtual reality groups at the baseline stage. Second, there were significant differences in engagement and fitness values between the two groups at the post-intervention stage. The qualitative research showed that elite athletes revealed various perceptions that virtual reality is easy and interesting, but the price is high, and that users should have technology literacy, or it would be less meaningful. Conclusions. This study confirms that virtual reality training was a positive and effective method to bring back engagement and physical fitness among elite Karate athletes.

Introduction: Telehealth has become a key tool to improve access to healthcare, particularly in contexts with geographical barriers. Its effective implementation relies on integrating technology with clinical knowledge, which requires specific competencies and interdisciplinary collaboration to ensure equitable care.Objective: To describe how interdisciplinarity influences the implementation and effectiveness of telehealth, identifying the challenges, opportunities, and necessary competencies from the perspective of healthcare professionals in the Biobío region, Chile.Methodology: A qualitative study was conducted through a focus group with 14 healthcare professionals from various disciplines. Data were analyzed using thematic analysis and co-occurrence analysis to identify relationships among key competencies.Results: The findings indicate that interdisciplinarity optimizes telehealth by combining clinical and technological knowledge, although it faces challenges such as the need for training in communication and adaptability competencies. The importance of skilled human resources and robust digital infrastructure is also highlighted.Conclusions: Interdisciplinary collaboration is essential for the success of telehealth, enabling patient-centered care and promoting health equity. Ongoing training in specific competencies and adequate technological support are necessary to ensure the sustainability and effectiveness of telehealth in the region.

Introduction: Before the COVID-19 pandemic, telemedicine and telehealth faced legal, technological, and cultural regulatory limitations. The health crisis boosted its massive adoption, enhancing its continuity over time. The objective of this review is to determine the projections of telehealth and telemedicine in the post-COVID-19 era and the factors that condition its growth.Methods: A systematic review was carried out following the PRISMA-ScR guidelines. The databases consulted were PubMed, Web of Science, and Scopus. 19 relevant studies were selected from an initial total of 96.Results: The pandemic accelerated the adoption of telemedicine, maintaining its use in areas such as mental health and chronic diseases. Factors associated with the use and development of technologies, added to cultural and economic aspects, have hindered its growth.Conclusions: Telehealth and telemedicine have improved access to health, but their sustainability requires resolving technological inequalities, in addition to guaranteeing privacy and security standards.

Governments offer resource user rights, such as individual and collective agricultural land rights, fishing quotas, and territorial user rights in marine activities, to induce economic development and efficient resource use. Yet, user rights and improved incomes do not always lead to project uptake, as in rural-rural migration. Marine user rights may differ from land tenure rights, especially when rights are individual or collective. We explore household survey data from Chile about participation in projects linking marine resource activities with user rights across payoff levels and commute/relocation ‘disruption’ costs. Households are more likely to participate in projects with low disruption costs and high incomes, yet many households reject lucrative projects. The household's existing user rights and the project's activity–rights pairs affect project participation levels, with differences across collective and individually-held rights. These results inform policy aimed at increasing incomes and resource use efficiency through marine resource projects with user rights.

In-depth research has been done in the literature on applying sophisticated modulation and control systems for power converters, such as Feedback Quantizer and Predictive Control. This research aims to enhance the Feedback Quantizer, a closed-loop modulation technique used in three-phase voltage source inverters. This method naturally reduces harmonics at low frequencies, which harms electrical machinery like transformers and AC motors. This modulation technique achieves an excellent follow-up of the fundamental voltage reference. One of the disadvantages of Feedback Quantizer are the low sampling time to achieve a good waveform quality; in addition, as it is not a carrier-based method, the switching frequency is variable, resulting in a dispersed harmonic spectrum. The three-phase voltage source inverter has eight valid states to monitor the voltage reference; the proposal consists of modifying the feedback quantizer modulation using virtual vectors by discrete space vectors, which achieves a better follow-up. The proposal considers a simplified implementation of discrete space vectors in such a way as to reduce the computational cost to obtain voltage and current waveforms with low WTHD, THD distortion, and a defined harmonic spectrum but with a high sampling time. The proposed modulation scheme obtains a THD of less than 2% in the load current, reducing the noise produced by the traditional scheme of Feedback Quantizer and using a fixed switching frequency for a sampling time of ( 200 μ s). The above is an improvement compared to the conventional Feedback Quantizer. Additionally, it was possible to reduce the mathematical operations of the algorithm by a factor of 5.38 by using strategies to simplify the algorithm of the suggested scheme. The proposed technique operates correctly, according to experimental tests.INDEX TERMS Feedback quantizer, discrete space vector modulation, total harmonic distortion, weighted total harmonic distortion, voltage source converter, modulation scheme.

The use of renewable energy sources (RESs) together with energy storage systems (ESSs) allows for smoothing power variations, thus improving power backup capabilities and power quality in the electric power grid. These applications require power converters to transfer energy between the renewable generator or energy storage and the power grid. In any case, the control algorithm of the power converter requires the synchronization method to provide a correct estimation of the instantaneous voltage of the power grid. This work provides engineers and researchers with an accessible platform at a low cost (less than USD 100) and a methodology for the experimental validation of digital synchronization algorithms as a step before their implementation in grid-connected equipment. The methodology evaluates the performance of the digital algorithms when there are variations in amplitude, frequency, phase, and harmonic content in the emulated three-phase power grid, as well as the execution times (tex), while a digital platform emulates the electrical signals and generates reference signals for the evaluation. To illustrate this proposal, two synchronization algorithms—SRF-PLL and DSOGI-PLL with a low-pass filter—are implemented in a digital controller and tested. The evaluation tool confirms the algorithms’ performance and shows that the execution time of DSOGI-PLL is 91% longer than that of SRF-PLL, which is well known in the literature.

Toxic organic pollutants are significant and critical concerns in environmental and ecological processes. Consequently, the environmental remediation of such toxic organic contaminants is a significant concern. We present the fabrication of the highly stable and efficient catalyst for the aqueous phase catalytic reduction of organic pollutants utilizing CuCo bimetallic nanoparticles immobilized amine-functionalized mesoporous KIT-6 support (CuCo@KIT-6). The formation of CuCo bimetallic NPs into the KIT-6 support was shown by HR-TEM image with the particle size of 1.60 ± 0.46 nm. CuCo@KIT-6 catalyst exhibited superior reactivity for 4-nitrophenol (4-NP) reduction within 12 min than the monometallic counterparts. The rate constant (kapp) of CuCo@KIT-6 (0.3938 min−1) was higher than the mono-metallic catalysts (Cu@KIT-6 (0.1438 min−1) and Co@KIT-6 (0.0052 min−1)). CuCo@KIT-6 demonstrated good catalytic behaviors for the degradation of multiple pollutants including 2-nitrophenol (2-NP) (0.5395 min−1), 3-nitrophenol (3-NP) (0.8262 min−1), 2-nitroaniline (2-NA) (1.5051 min−1), 4-nitroaniline (4-NA) (0.7740 min−1), 4-(4-nitrophenyl)morpholine (4-NM) (0.6243 min−1), 2,4-dinitrophenol (2,4-DNP) (0.3297 min−1), 4-(2-fluoro-4-nitrophenyl) morpholine (4-FNM) (0.7411 min−1), rhodamine b (RhB) (1.7550 min−1), congo red (CR) (0.1900 min−1), methyl orange (MO) (1.3077 min−1), and eosin Y (EY) (0.5071 min−1). The CuCo@KIT-6 catalyst showed high efficiency for the simultaneous degradation of contaminants (4-NP + RhB + CR + MO + EY) in the complex environment. In addition, CuCo@KIT-6 catalyst demonstrated excellent stability with promising reusability. Thus, the CuCo@KIT-6 catalyst holds great promise for industrial wastewater treatment.

In this research an experimental study to assess the cyclic behavior of bolted moment connection in racks structures is performed. The effect of bolt pretension in the response is evaluated. Sixteen full-scale steel rack joint configurations were subjected to cyclic load according to the protocol established in AISC Seismic provisions. The cyclic performance was evaluated in terms of hysteretic response, failure mechanism, energy dissipation, stiffness, and rotation on the components. Two different configurations were studied. The results showed that the steel rack connections using a 70 % of bolt pretension can accommodate a 0.8 My at 0.04 rad of drift angle, while the joints without bolt pretension reached values below 0.7 My at 4 % of rotation. The failure mechanism was controlled by weld fracture at 4 % of the rotation. A high dispersion in the energy dissipation pattern was obtained and a drop in energy dissipation of up to 4 times in all specimens tested for a 4 % rotation was developed. This phenomenon is due to the welding rupture between the beam and the L-connector. A degradation of the secant stiffness reached up to 60 % for 2 % rotation. Finally, the most important effect of bolt pretension on the cyclic response of steel rack connections was achieved in the increase of flexural resistance and rotation developed.

Cold-formed steel (CFS) members offer significant advantages over hot-rolled sections, primarily due to their high strength-to-weight ratio and versatility in forming various cross-sectional shapes. These attributes make CFS an efficient choice for design and construction. This paper reviews current design methods for CFS, focusing on the impact of initial imperfections. It also examines various techniques for measuring residual stress in CFS sections, including analytical, experimental, and numerical approaches. The study concludes that while analytical methods are effective, they become complex when accounting for material anisotropy. Laboratory techniques provide reliable measurements but are limited in detecting through-thickness residual stresses. Numerical approaches offer comprehensive insights but require further validation across different material and geometric configurations. The paper highlights the need for advanced analytical models, improved laboratory methods, and expanded numerical techniques to address existing knowledge gaps in residual stress assessment for CFS structures.