University of Bío-Bío

Beet is a vegetable that has an important content of sugars, antioxidants and minerals, which are essential components for the vitality of the human body. Cryoconcentrated beet juice is an interesting osmotic agent for enriching plant tissue. The main aim of this research was to study the impregnation and retention of the bioactive compounds of cryoconcentrated beet juice in apple slices using osmotic dehydration (OD) with and without pulse vacuum (PV) application and ohmic heating (OH). Apple slices (4 × 3 × 0.5 cm) were impregnated with cryoconcentrated beet juice (50°Brix) at 30, 40 or 50 °C for 180 min with a 5 min pulsed vacuum application at the beginning of the process and an electric field of 1.33 V/cm. The water content, soluble solids, phenolic content, antioxidant capacity, betacyanins, betaxanthins and betalains content were analyzed. Samples treated with OD/OH and PVOD/OH at 50 °C for 120 min achieved the greatest loss of water and the greatest impregnation of bioactive compounds from the cryoconcentrated beet juice. The OD/OH and PVOD/OH treatments helped to retain the bioactive components and increase antioxidant capacity at all temperatures. PVOD/OH at 50 °C yielded apple slices with the highest total phenolic content during processing, and the highest concentration of betacyanins and betalains was obtained in samples treated with OD/OH at 50 °C. The results show that cryoconcentration, PV application and OH technologies are the excellent alternatives for the impregnation and retention of natural bioactive components for obtaining fortified foods.

In this study, we conducted a comprehensive analysis of various Chilean bean varieties, examining how cooking influences their nutritional and culinary characteristics. We found that these varieties exhibit significant differences in their protein, lipid, ash, fiber, and carbohydrate profiles in both raw and cooked states. Generally, cooking tends to increase proteins and carbohydrates while decreasing lipids and ashes, although these changes vary depending on the variety. The importance of cooking time in the culinary quality of beans is noteworthy. Varieties requiring shorter cooking times are generally preferred due to their tender texture and pleasant taste. Water absorption processes and seed coat permeability play a crucial role in determining these cooking times. Regarding nutritional implications, we observed that cooking can significantly impact the caloric content of beans, with some varieties experiencing increases while others show decreases. This phenomenon underscores the importance of understanding how the cooking process affects the nutritional quality of foods. These findings are of paramount importance in selecting suitable varieties based on culinary preferences and nutritional needs, thereby contributing to promoting a balanced and healthy diet.

In this work, we suggest a simpler model to study the motion around irregularly elongated asteroids. This new model includes a variable density for the elongated asteroid. More precisely, we consider the motion of an infinitesimal mass attracted by the gravitational force induced by a body modeled as a non-homogeneous straight segment. We consider two situations: the segment can rotate uniformly with angular velocity $\omega \ne 0$, or it is fixed (i.e., $\omega =0$). The aim of this paper is to prove the existence of different family of periodic solutions for this problem, such as those obtained by the averaging method for Hamiltonian or as the continuation method of Poincaré by using discrete symmetries. We prove the existence of several families of periodic solutions as a continuation of circular orbits of the (fixed or rotating) Kepler problem. We also obtain periodic solutions as a continuation of circular solutions of the Coriolis problem. The analysis of the linear stability of some periodic solutions is considered. The families of periodic orbits studied in this work constitute an example of the variety of orbits that can be followed by a particle orbiting an elongated asteroid from an analytic point of view. This helps us understand the dynamics around these bodies.

Functional polymeric materials play a critical role in optimizing flocculation and sedimentation processes in mining tailings, where complex interactions with mineral surfaces govern polymer performance. This study examines the structure–performance relationship, which describes how the internal structure of aggregates (e.g., compactness, porosity and fractal dimension) influences sedimentation behavior, specifically for anionic polyacrylamide (SNF 704) in kaolin-quartz-pyrite suspensions at a pH of 10.5. Using focused beam reflectance measurement (FBRM) and static sedimentation tests, we demonstrate that pyrite exhibits the highest flocculant adsorption capacity, inducing a train-like polymer conformation on its surface. This reduces the formation of effective polymeric bridges, resulting in less compact and more porous aggregates that negatively impact sedimentation rates. Increasing the flocculant dosage improves the capture of fine particles; however, at high pyrite concentrations, rapid saturation of adsorption sites limits flocculation efficiency. Additionally, the fractal dimension of the aggregates decreases with increasing pyrite content, revealing more open structures that hinder consolidation. These findings underscore the importance of optimizing polymer dosage and tailoring flocculant design to the mineralogical composition, thereby enhancing water recovery and sustainability in mining operations. This study highlights the role of structure–property relationships in polymeric flocculants and their potential for next-generation tailings management solutions.

This paper explores, as a proof-of-concept, the impact of definitive and intermediate host mobility on the transmission and spread of cystic echinococcosis by characterizing disease dynamics using three classical epidemic models: S-E-I-R for the accidental intermediate host, S-E-I for the habitual intermediate host, and S-I-S for the definitive host. The simulations revealed a significant relationship between the mobility of dogs and the increase in infected sheep. Specifically, for each infected dog, there were twice as many infected sheep as in a situation where mobility was not a factor. The initial conditions took into account that the prevalence of the disease in dogs is higher in rural areas than in peri-urban areas, as has been observed in the Magallanes region of Chile. The results of the simulations suggest that mobility can have a role in the propagation of the disease in humans. Furthermore, the sensitivity index on R0 indicates that a 10% reduction in the average time spent by peri-urban dogs in urban and rural areas could result in a decrease of approximately 1% in R0. In conclusion, including the host mobility factor allows us to observe that, in general, the number of infected in the domestic cycle of the disease increases, i.e., our mathematical model provides valuable information on the impact of host mobility on the transmission and spread of cystic echinococcosis.

Chalcopyrite, the main source of copper worldwide, faces challenges in its flotation due to the complexity of its surface interactions and its coexistence with other minerals. Given the need for papers that show the current state of knowledge and new trends, this article reviews the developments of chalcopyrite flotation, with a focus on molecular design. A comprehensive bibliography search was conducted using keywords and specific queries in the Scopus database, applying inclusion and exclusion criteria to select the most relevant articles. The results were structured in three research periods, according to temporal and thematic criteria. The first period approaches the fundamentals of the process, considering variables as reagent dosage, surface chemistry and the influence of metal ions on recovery and selectivity. The second period explores the analysis and measurement techniques for the development of more selective and sustainable reagents. The third period analyzes the integration of advanced tools, such as molecular dynamic simulations and machine learning, into the understanding of adsorption mechanisms and custom reagent design. It is expected that this work will become a theoretical reference in future research and for mining companies that intend to innovate in their copper flotation and recovery processes.

One of the most significant challenges in research related to nutritional epidemiology is the achievement of high accuracy and validity of dietary data to establish an adequate link between dietary exposure and health outcomes. Recently, the emergence of artificial intelligence (AI) in various fields has filled this gap with advanced statistical models and techniques for nutrient and food analysis. We aimed to systematically review available evidence regarding the validity and accuracy of AI-based dietary intake assessment methods (AI-DIA). In accordance with PRISMA guidelines, an exhaustive search of the EMBASE, PubMed, Scopus and Web of Science databases was conducted to identify relevant publications from their inception to 1 December 2024. Thirteen studies that met the inclusion criteria were included in this analysis. Of the studies identified, 61·5 % were conducted in preclinical settings. Likewise, 46·2 % used AI techniques based on deep learning and 15·3 % on machine learning. Correlation coefficients of over 0·7 were reported in six articles concerning the estimation of calories between the AI and traditional assessment methods. Similarly, six studies obtained a correlation above 0·7 for macronutrients. In the case of micronutrients, four studies achieved the correlation mentioned above. A moderate risk of bias was observed in 61·5 % ( n 8) of the articles analysed, with confounding bias being the most frequently observed. AI-DIA methods are promising, reliable and valid alternatives for nutrient and food estimations. However, more research comparing different populations is needed, as well as larger sample sizes, to ensure the validity of the experimental designs.

We describe completely the dynamics of the three-dimensional Muthuswamy–Chua systems x ˙ = y , y ˙ = − x 3 + y 2 − y z 2 2 , z ˙ = y − α z − y z, in the infinity of the Poincaré ball for all values of α ∈ R. Additionally, we provide a complete description of the dynamics of this differential system when α = 0.

Natural fiber-reinforced composites could be obtained by utilizing agricultural wastes, fallen leaves, or abandoned materials as reinforcements after their usage as a way to reduce environmental impacts such as to stop deforestation, i.e., cutting down of plants and trees for their fibers, and in waste management, which includes recyling of natural wastes and minimizing the use of nonbiodegradable synthetic composites by replacing it with their natural fiber counterparts. As an outcome, leaves from a Terminalia catappa (Tc) tree grown in the Kanyakumari district that falls off in large quantities throughout the winter are gathered and examined. The leaves are treated with NaOH and KMnO4. In this investigation, all three powdered samples (raw, alkali treated, and permanganate treated Tc leaf fibers) are sent to chemical analysis, powder X-ray diffraction (p-XRD), Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDAX), thermal analysis (TGA-DTA), and carbon hydrogen nitrogen sulfur (CHNS) analysis. The results of the research showed that the powdered Tc leaf samples had high levels of cellulose (≈ 50%), crystallinity index (≈ 50–65%), and crystallite size (≈ 3 nm). There are various vibrational bands associated with them. The rough surface of the raw and treated Tc powder samples and their particle size (≈ 50–100 μm), as revealed by the SEM images, might aid in good adherence with the matrix. According to EDAX and CHNS analyses, there is a high carbon content in all of the samples. The fibers have an activation energy (≈ 55–60 kJ/mol) and maximum temperature limit (≈ 500 °C) that are comparable to many other natural fibers. The density of Tc leaf fibers (≈ 0.2 g/cm³) is very low and so could be used in lightweight composite applications. The chemical treatments enhanced the qualities of Tc fibers to a certain extent. In various polymers, rubber, or concrete matrices where the inclusion of natural fiber reinforcement is desired, all three samples could function as potential reinforcements.

Background: Citizenship plays a fundamental role in the management of socio-natural disaster risk, especially given the increasing impact and frequency of these events. In this context, disaster response is marked by both formal and spontaneous volunteerism. Method: Using a non-probabilistic sample of 101 volunteers and comparing the social representation of formal volunteers with spontaneous volunteers, prototypical and categorical analyses of social representations were conducted. Results: Differences were identified between formal volunteers, whose social representation reflects a strong value-oriented and collaborative vision focused on social capital, and spontaneous volunteers, whose social representation is directed toward prosocial values, emotions, and the heroic actions associated with volunteerism. Conclusions: New avenues are proposed for exercising and strengthening formal volunteerism, accompanied by processes that enable the identification of common value axes and suitability for risk-related work. Additionally, the motivations and actions of spontaneous volunteers are discussed. Finally, sustained coordination is proposed among institutions involved in risk management, formal volunteers, and spontaneous volunteers to optimize human resource management in emergencies.

An education oriented towards learning must necessarily include assessment techniques and instruments that effectively achieve this goal. Currently, assessment has become a crucial element, leading to the promulgation of legal regulations to govern it. This study aimed to explore the perceptions of assessment in three Chilean universities among faculty members vs. practicum students from two cohorts of Chilean Initial Teacher Education in Physical Education (ITEPE) from two cohorts from subsequent moments, with a difference of four years. The study followed a quantitative, cross-sectional, and comparative approach and the sample consisted of a total of 458 participants, including 1st Group: n = 162 practicum students (S1) 2019–20 (M = 22.5, SD = 3.1) and 44 faculty members (FM1) from the same cohort (M = 42.3, SD = 11.2) vs. 197 practicum students (S2) 2023–24 (M = 23.6, SD = 2.2) and 55 faculty members (FM2) from this cohort (M = 40.4, SD = 10.4). Data were collected using the “Questionnaire for the Study of the Assessment System”. The results revealed significant differences between students and faculty regarding the perception of the use of assessment instruments in ITEPE. The 2023–24 cohort students perceived a greater presence of portfolios compared to their peers from four years ago, while faculty from the latest cohort indicated a perception of higher use of traditional exams. In conclusion, it can be observed that decision-making predominantly falls on the faculty, as evidenced by discrepancies regarding feedback and student participation in grade determination. This reinforces the idea that the process remains teacher-centered.

We investigate a nonlinear multiphysics model motivated by ultrasound-enhanced drug delivery. The acoustic pressure field is modeled by Westervelt’s quasilinear wave equation to adequately capture the nonlinear effects in ultrasound propagation. The non-local attenuation characteristic for soft biological media is modeled by acoustic damping of the time-fractional type. Additionally, acoustic medium parameters are allowed to depend on the temperature of the medium. The wave equation is coupled to the nonlinear Pennes heat equation with a pressure-dependent source to account for ultrasound waves heating up the tissue. Finally, the drug concentration is obtained as the solution to an advection–diffusion equation with a pressure-dependent velocity. Toward gaining a rigorous understanding of this system, we set up a fixed-point argument in the analysis combined with devising energy estimates that can accommodate the time-fractional damping. The energy arguments are, in part, carried out by employing time-weighted test functions to reduce the regularity assumptions on the initial temperature. The analysis reveals that different smoothness of the initial pressure, temperature, and concentration fields is needed as well as smallness of the pressure-temperature data in order to ensure non-degeneracy of the system and establish well-posedness. Our theoretical considerations are complemented by a numerical investigation of the system under more realistic boundary conditions. The numerical experiments, performed in different computational scenarios, underline the importance of considering nonlinear effects when modeling ultrasound-targeted drug delivery.

Phacelia secunda J.F. Gmel. (Boraginaceae) is a widely distributed insect-pollinated perennial herb. In central Chile (33° S), it occurs from the sea level up to 3600 m in the Andes, exhibiting broad morphological variation. In this study, we developed and characterized novel polymorphic microsatellites for this species, using an Illimina MiSeq sequencing platform. Nineteen polymorphic loci were obtained, with alleles numbers ranging from 3 to 13 per locus (mean = 5.84). Observed (HO) and expected heterozygosities (HE) ranged from 0.050 to 0.900 and from 0.049 to 0.825, respectively. These markers were applied to assess the genetic diversity and population structure along an altitudinal spanning from 1600 to 3600 m. The highest elevation population exhibited significantly lower within-population genetic diversity compared to lower-elevation populations. Significant population differentiation was observed along the gradient. Gene flow estimates support a stepping-stone like mode of migration, with greater exchange between adjacent elevations. These new microsatellites provide a valuable tool for elucidating the influence of altitude on genetic diversity and structure, and for evaluating the roles of local adaptation and phenotypic plasticity in shaping population variation.

In this article, we introduce a distribution that is an extension of the Power Maxwell (PM) distribution, which is based on the quotient of two independent random variables. These are the PM and a gamma distribution, respectively. In this way, the result is a model with greater kurtosis than the PM distribution. We study its probability density function and some properties, such as moments, asymmetry and kurtosis coefficient. An EM algorithm is proposed to estimate the parameters via the maximum likelihood method. A simulation study is carried out to study the asymptotic behaviour of our estimators. An application to a real dataset is also included.

Objective: The COVID-19 pandemic interrupted multicomponent face-to-face interventions with older people, which became an opportunity for the implementation of these interventions in telehealth modality, as well as the analysis of the facilitators and barriers. This qualitative study examines the facilitators and barriers, from the users’ perspective, of a promotional–preventive multicomponent intervention in older people using an asynchronous telehealth modality during the COVID-19 pandemic, as a continuation of the face-to-face intervention. Methods: Semistructured in-depth interviews were used. An intentional sampling was conducted over eight groups of older people in a city, who were part of a multicomponent (physical activity, cognitive stimulation, and education) telehealth (videos, infographics, manual, and WhatsApp) promotional–preventive intervention, who came from the same face-to-face intervention. After intervention, two groups were identified (intervention and control). Telephone interviews, until theoretical saturation was reached, were audio-recorded and transcribed. Thematic analysis was conducted using Atlas.ti. Results: Twenty-six older people of both sexes, aged 60–88 years, were interviewed (14 intervened and 12 controls). Six themes were identified: positive aspects of telehealth, telehealth facilitators, preference for face-to-face modality over telehealth modality, telehealth barriers, reasons for not performing telehealth, and coping strategies in the pandemic: specifically, as facilitators, participating in the company of others, having participated in the same intervention previously (face-to-face modality), good knowledge of digital literacy, self-motivation, commitment to the program, and the emergence of innate leaders, and as barriers, pain during physical activity, complexity of cognitive exercises included in cognitive stimulation, poor digital literacy, and not having support from others. Conclusion: This is the first qualitative study that identifies facilitators and barriers of a multicomponent intervention in an asynchronous telehealth modality, as a continuation of the same face-to-face intervention. The asynchronous telehealth modality could be used regularly with older people in rural areas, in situations of disability and/or with care needs, pandemic scenarios, or natural disasters.

Inflammation contributes to the onset and development of many diseases, including neurodegenerative diseases, caused by the activation of microglia, leading to neurological deterioration. Nuclear factor-κB (NF-κB) is one of the most relevant pathways for identifying anti-inflammatory molecules. In this study, polygodial and isotadeonal, two drimane sesquiterpene dialdehydes, were isolated from Drimys winteri, a medicinal tree of the Mapuche people in Chile. Isotadeonal, or epi-polygodial, was obtained from polygodial by epimerization in basic media (60% yield, Na2CO3, r/t, 24 h). Both sesquiterpenoids were evaluated on the NF-κB pathway, with the result that isotadeonal inhibited the phosphorylation of IκB-α at 10 μM with higher potency by Western blotting. The final inhibition of the pathway was evaluated using a SEAP reporter (secreted alkaline phosphatase) on THP-1 cells. Isotadeonal inhibited SEAP with higher potency than polygodial, quercetin, and CAPE (phenethyl ester of caffeic acid). In silico analysis suggests that the α-aldehyde of isotadeonal adopts a more stable conformation in the active pocket of IκB-α than polygodial.

Carbon quantum dots (CQD) are an emergent nanomaterial with unique optical and biological properties. However, the purification of CQD is one of the bottlenecks that makes it difficult to scale for application in different areas. In this work, we explore for the first time the potential of centrifugal partition chromatography (CPC) as an alternative preparative technology to achieve the purification of CQD at the gram scale. The hydrothermal method was used to synthesize CQD from avocado peels. After 6 h at 250 °C, a complex mix of strong blue-fluorescent CQDs were obtained and submitted to CPC fractionation without pretreatment. The best results were obtained with the solvent system n-hexane–ethyl acetate–methanol–water (1:2:1:2, v/v/v/v), in an elution-extrusion protocol. Nine fractions were obtained and were characterized by UV-VIS spectrophotometry, Fourier transform infrared (F-TIR), and field emission scanning electron microscopy (FESEM), confirming the presence of CQD of different sizes. CPC fractionations indicate that a polarity-based separation mechanism can be used to purify CQD. Interestingly, four fractions showed antibacterial and anti-biofilm effects on Pseudomonas putida and Listeria monocytogenes. Therefore, CPC allows for better refining of this type of nanomaterial, and in combination with other techniques, it would serve to obtain CQD of higher purity, facilitating the physicochemical and bioactivity characterization of these particles. CPC would also allow the use of waste, such as avocado peels, to obtain new materials.