Repositorio Académico de la Universidad Católica del Maule
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Comment on “change in physical activity and its association with decline in kidney function: A UK biobank-based cohort study” by Liu et al.—The authors' reply
No full textPredictors of suicide attempts and reattempts in a sample of chilean adolescents
No full textBackground: Suicide is a public health problem worldwide, especially among adolescents. Chile is one of the Latin American countries with the highest suicide rates; however, few studies have investigated the risk factors for suicide attempts in this specific population. We aimed to describe the suicidal behaviour of Chilean adolescents and to explore the factors associated with suicide attempts and reattempts in this population.
Methods: Adolescents (10–19 years) with a diagnosis of psychiatric disorders were recruited in the Maule region, Chile, between 2018 and 2021. Sociodemographic and clinical variables were collected. Logistic regression was performed to explore the association between these variables and suicide attempts.
Results: Factors associated with increased odds of suicide attempts included age, sexual orientation, Adverse Childhood Events (ACEs) and past and current symptomatology. Factors that decreased the odds of suicide attempts were previous psychotherapy or pharmacological treatment, responsiveness and warmth from mother and father. Active symptoms at the time of assessment increased the odds of reattempting suicide.
Conclusions: In our sample, clinical and trauma-related factors emerged as the most important factors in predicting suicide attempts. Although age, sexual orientation and family dysfunction also played a notable role, positive relationships with parents seemed to be protective. In addition, current symptoms of stress, anxiety and depression significantly increased the likelihood of reattempts. These findings provide valuable knowledge about suicidality in Chile, although further research is needed to expand the evidence in our media
Multi-channel speech enhancement using labelled random finite sets and a neural beamformer in cocktail party scenario
No full textIn this research, a multi-channel target speech enhancement scheme is proposed that is based on deep learning (DL) architecture and assisted by multi-source tracking using a labeled random finite set (RFS) framework. A neural network based on minimum variance distortionless response (MVDR) beamformer is considered as the beamformer of choice, where a residual dense convolutional graph-U-Net is applied in a generative adversarial network (GAN) setting to model the beamformer for target speech enhancement under reverberant conditions involving multiple moving speech sources. The input dataset for this neural architecture is constructed by applying multi-source tracking using multi-sensor generalized labeled multi-Bernoulli (MS-GLMB) filtering, which belongs to the labeled RFS framework, to obtain estimations of the sources’ positions and the associated labels (corresponding to each source) at each time frame with high accuracy under the effect of undesirable factors like reverberation and background noise. The tracked sources’ positions and associated labels help to correctly discriminate the target source from the interferers across all time frames and generate time–frequency (T-F) masks corresponding to the target source from the output of a time-varying, minimum variance distortionless response (MVDR) beamformer. These T-F masks constitute the target label set used to train the proposed deep neural architecture to perform target speech enhancement. The exploitation of MS-GLMB filtering and a time-varying MVDR beamformer help in providing the spatial information of the sources, in addition to the spectral information, within the neural speech enhancement framework during the training phase. Moreover, the application of the GAN framework takes advantage of adversarial optimization as an alternative to maximum likelihood (ML)-based frameworks, which further boosts the performance of target speech enhancement under reverberant conditions. The computer simulations demonstrate that the proposed approach leads to better target speech enhancement performance compared with existing state-of-the-art DL-based methodologies which do not incorporate the labeled RFS-based approach, something which is evident from the 75% ESTOI and PESQ of 2.70 achieved by the proposed approach as compared with the 46.74% ESTOI and PESQ of 1.84 achieved by Mask-MVDR with self-attention mechanism at a reverberation time (RT60) of 550 ms
Effects of a CrossFit training program on body composition and physical fitness in novice and advanced practitioners: an inter-individual analysis
No full textBackground: CrossFit® has become a popular and effective training methodology. This study aimed to compare the effects of a four-week CrossFit training program and analyze the inter-individual variability on body composition (fat mass and fat-free mass) and physical fitness (push-ups, military press, back squat, deadlift, countermovement jump (CMJ), sit-ups, and 30 m sprint speed) in novice and advanced practitioners. Methods: A quasi-experimental design was used, with single-blinded (evaluators) and 2 parallel groups: novices (n = 10; age = 22.30 ± 0.81) and advanced practitioners (n = 11; age = 22.80 ± 1.41). The intervention consisted of 3 weekly 75 min sessions (4 weeks), with pre- and post-assessments. A two-factor mixed ANOVA and inter-individual analyses to classify responders (Rs) and non-responders (NRs) were performed. Results: No significant interaction effects were found. However, the novice group significantly improved back squat performance (p = 0.031). Inter-individual analysis showed higher proportions of Rs in the novice group for back squat (40%), deadlift (20%), military press (10%), CMJ (10%), sit-ups (30%), push-ups (30%), and 30 m sprint speed (10%) compared to the advanced group. Conclusions: CrossFit program did not significantly affect body composition, but novices exhibited significant back squat improvements. Considering experience levels can enhance training outcomes
Impact of methyl Jasmonate on blueberry ripening fruits: assessment of cell wall thermal stability, nutritional parameters and antioxidant enzymatic activity
No full textIntroduction: The blueberry (Vaccinium spp.), recognized as one of the most significant horticultural crops globally, is valued for its rich bioactive compounds. In this study, we examine the effects of methyl jasmonate (MeJA) on blueberry, focusing on cell wall composition, nutritional properties, and antioxidant enzyme activity across two seasons (2022–2023). The objective is to evaluate the impact of MeJA treatments on fruit ripening dynamics and quality attributes.
Methodology: Blueberry plants were treated with single (T1) and double (T2) MeJA applications. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to assess thermal degradation patterns of cell wall polymers. Biochemical evaluations included phenolic content, antioxidant capacity (DPPH and FRAP assays), and anthocyanin accumulation during ripening. Enzymatic antioxidant activities (APX, CAT, SOD, and POD) were also analyzed to determine oxidative stress responses.
Results and discussion: Thermal degradation analysis revealed that green-stage fruits exhibited higher thermal stability than ripe fruits, with variations in pink-stage behavior between seasons. Biochemical assessments indicated a progressive decline in phenolic content and antioxidant capacity during ripening, whereas anthocyanin accumulation peaked in the blue stage, enhancing pigmentation. MeJA treatments significantly influenced antioxidant enzyme activity: T1 maximized APX, CAT, and SOD activities, while T2 amplified POD activity, contributing to oxidative stress tolerance and improved fruit quality. Furthermore, the modulation of hemicellulose fractions in TGA profiles suggests that MeJA helps maintain cell wall integrity, potentially reducing fruit softening during storage.
Conclusion: These findings indicate that MeJA enhances fruit resilience during ripening while preserving key biochemical properties critical for postharvest management. The observed improvements in antioxidant capacity, enzymatic activity, and cell wall stability suggest that MeJA could be a valuable tool for optimizing postharvest handling, extending shelf life, and enhancing the marketability of blueberries. This work provides a preliminary framework for integrating MeJA into sustainable horticultural practices to meet consumer demand for high-quality functional fruits
Association between cardiorespiratory fitness and mortality risk in the chilean population
No full textFUNDAMENTOS // El fitness cardiorrespiratorio disminuye el riesgo de enfermedades cardiometabólicas, de cáncer y la mortalidad. El objetivo de este trabajo fue evaluar la relación entre el fitness cardiorrespiratorio estimado con ecuación y la mortalidad por todas las causas en población chilena de ambos sexos, según los datos de la Encuesta Nacional de Salud (ENS) 2009-2010.
MÉTODOS // Se analizaron datos de 4.749 participantes de la ENS 2009-2010 tras 10,9 años de seguimiento. El fitness se estimó con la ecuación de Myers et al. y se clasificó en quintiles. Registros de mortalidad por cualquier causa se obtuvieron del Registro Civil e Identificación de Chile hasta el año 2020. Para evaluar la asociación entre fitness y mortalidad se utilizaron modelos de regresión de Cox ajustados por variables de confusión (demográficas, estado nutricional, estilos de vida y comorbilidades).
RESULTADOS // Durante los 10,9 años (RIQ: 10,8; 11,4) de seguimiento, 506 personas (10,6%) fallecieron. En comparación al quintil más bajo de fitness (12 MET) presentaron un 95% menos riesgo de mortalidad (HR: 0,05; 95% IC: 0,03; 0,09) y el riesgo de mortalidad fue un 28% menor por cada 1-MET de incremento en fitness (HR: 0,72 95% IC: 0,69; 0,75). Todas estas asociaciones fueron independientes de factores de confusión.
CONCLUSIONES // Se concluye que un mayor nivel de fitness se asocia con un menor riesgo de mortalidad, independientemente de factores confundentes, en población chilena después de 10,9 años de seguimiento
Effect of exercise on kidney-relevant biomarkers in the general population: a systematic review and meta-analysis
No full textObjective Physical activity (PA) has been generally recognised as beneficial for health. The effect of a change in PA on kidney biomarkers in healthy individuals without kidney disease remains unclear. This manuscript synthesised the evidence of the association of changes in PA with kidney biomarkers in the general population free from kidney disease.
Design Systematic review and meta-analysis.
Data sources Embase, PubMed, MEDLINE and Web of Science databases were searched from inception to 12 March 2023.
Eligibility criteria for selecting studies Studies of longitudinal or interventional design were selected initially. The following studies were excluded: (1) case-control studies, (2) studies where PA was measured at a single time point, (3) populations with known kidney disease, (4) studies evaluating the impact of a single episode/event of PA and (5) non-English language studies.
Data extraction and synthesis Two independent reviewers extracted data from a pre-designed table and assessed the risk of bias using the Cochrane Risk of Bias tool. Data were pooled using a random-effects model. Hedge’s g was used to synthesise effect sizes and obtain an overall estimate. Heterogeneity between studies was measured using I2. Funnel plots and Egger’s test were performed to evaluate the risk of biased results.
Results 16 interventional studies with randomised or non-randomised designs involving 500 participants were identified. The median follow-up was 84 days. 10 studies were at high risk of bias. Studies with low quality were published prior to the year 2000. Changes in PA were found only to have a positive association with serum creatinine (SCr) (Hedge’s g=0.69; 95% CI 0.13, 1.24; I2=81.37%) and not with plasma renin activity (PRA), urea, or urine albumin-to-creatinine ratio (UACR). The positive association was only observed in people with obesity and those who exercised for more than 84 days.
Conclusions Higher levels of PA are associated with increased SCr levels in healthy people. It remains unclear if this association is related to impaired kidney function or gain in muscle mass, as data on other kidney biomarkers did not support a certain link.
PROSPERO registration number This review has been registered on PROSPERO (CRD42023407820)
Exploring the impact of sentential negation on inhibitory motor networks: insights from paired-pulse TMS
No full textThe embodied approach to language meaning suggests that negation with action verbs decreases activation of the negated concept, reflected in reduced motor-evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS). This study aims to explore how action negation influences inhibitory and facilitatory mechanisms within the primary motor cortex (M1) using paired-pulse TMS (ppTMS). We evaluated corticospinal excitability (CSE), short intracortical inhibition (SICI), indexing GABAA activity, and intracortical facilitation (ICF), related to glutamatergic activity. Participants read action and attentional sentences, presented in affirmative and negative form, with TMS pulses administered over the left M1 at 250 ms from verb onset. Results show negated action sentences differently modulate CSE and SICI compared to affirmative ones, indicating GABAA activity of negation. No differences emerged for attentional sentences, nor for ICF stimulation. This study confirms the suppressive impact of action negation on CSE and highlights inhibitory networks’ role in action negation processing within M1
Metal-catalyzed decarboxylation of oxaloacetic acid studied in silico and in vitro, implications for enzymatic and prebiotic catalysis
No full textDuring the decarboxylation of oxaloacetic acid (OAA), an α-keto acid that participates in the central metabolic pathways of all organisms, its fourth carbon is released in the form of CO2 through a metal-catalyzed reaction. In the context of prebiotic chemistry, it is generally accepted that metalloenzymes catalyse reactions that could have originally occurred abiotically mediated by metals. In this study, we investigate the effect of various divalent cations (Ni2+, Co2+, Mn2+ and Mg2+) on the non-enzymatic decarboxylation rate of oxaloacetic acid (OAA) using both in silico quantum mechanical calculations and in vitro experimental analysis. Our experimental findings demonstrate that for the rate of OAA decarboxylation, the cations followed the order Ni2+ > Co2+ > Mg2+ > Mn2+. Theoretical results, utilizing the enolpyruvate metal complex as the final stage of the reaction, showed that the Ni2+ complex had the lowest decarboxylation energy and negative Gibbs free energy compared to other complexes. Additionally, it exhibited a lower HOMO-LUMO gap, indicating its potential to aid in the decarboxylation reaction. Given that decarboxylases in current metabolism primarily employ Mg2+ and Mn2+ but not Ni2+, we consider how the cation that performs better in the abiotic reaction was not selected as the catalytic centre of the enzyme-based reaction in current biochemistry
A novel genotype of Babesia microti-like group in Ixodes montoyanus ticks parasitizing the Andean bear (Tremarctos ornatus) in Ecuador
No full textBabesia species (Piroplasmida) are hemoparasites that infect erythrocytes of mammals and birds and are mainly transmitted by hard ticks (Acari: Ixodidae). These hemoparasites are known to be the second most common parasites infecting mammals, after trypanosomes, and some species may cause malaria-like disease in humans. Diagnosis and understanding of Babesia diversity increasingly rely on genetic data obtained through molecular techniques. Among hard ticks, several Ixodes species are known vectors of Babesia microti-like species in the Northern Hemisphere. Recently, Ixodes and Amblyomma ticks have been recorded parasitizing the Andean bear (Tremarctos ornatus) in Ecuador. Previous reports have suggested babesiosis in a fatal case of this threatened bear species in that country. This study aimed to detect Piroplasmida DNA in hard ticks collected from Andean bears at two sites in Ecuador. This species plays a critical role as an ecological engineer and a seed disperses, contributing significantly to the maintenance and health of Andean ecosystems. Twelve ticks screened with conventional PCR and Piroplasmida DNA was amplified from one Ixodes montoyanus tick collected from a free-living female Andean bear at Llanganates National Park. Two Babesia sequences were characterized: one for the 18 S ribosomal rRNA gene and another for the cytochrome c oxidase 1 gene. Phylogenetic analyses for both loci placed these sequences within the B. microti-like clade. This study reports a novel B. microti-like genotype identified in an I. montoyanus parasitizing a female Andean bear, contributing to the knowledge of the diversity of this group in South America. Given their conservation status, future epidemiological surveillance of Babesia and other tick-borne infectious agents in Andean bears is needed