SYNOPSIS The large scale of cave mines leads to many challenges, including operational logistics and geomechanics design. In current practice, pillar stability assessment relies almost exclusively on stress analysis. However, stability is also affected by other factors including those related to operational aspects of the mining method, the effects of which are difficult to account for during the design stages. In this paper we present a case study of the application of a machine learning approach to evaluate the influence of these operational factors on pillar stability at the Chuquicamata underground cave mine in northern Chile. Due to the likely multi-factorial damage process leading to collapses and considering the different pillar conditions, a tree-based machine learning method was used and analysed to improve the understanding of the relative importance of the various contributing factors. Unlike stress analysis methods, it does not require any a priori knowledge of failure mechanisms, nor the calibration of associated controlling parameters. The proposed random forest model predicted pillar collapses with 80% accuracy despite limited samples to model from. The main contributing factors to collapses were found to be related to available pillar volume, cave front geometry, and time under abutment stress conditions. The effects and interactions of such factors were also studied, showing that careful and improved control over operational conditions can significantly reduce the likelihood of pillar collapses. These conclusions could not have been obtained from stress analysis alone, illustrating the complementary nature of conventional stress analysis and machine learning approaches.

Resumen Introducción: La obesidad mórbida se asocia a alteraciones de la capacidad de caminar, sin embargo se desconoce cómo es el comportamiento de la prueba de caminata de 6 minutos en sujetos con incrementos del índice de masa corporal (IMC). Objetivo: Describir el comportamiento de la prueba de caminata de 6 minutos en sujetos con IMC normal hasta la obesidad mórbida. Métodos: Mediante un diseño transversal analítico se estudiaron sujetos de ambos sexos de 18 a 60 años con IMC: normal (18.5-24.9 kg/m2), sobrepeso (25-29.9 kg/m2), obesidad (30-39.9 kg/m2), obesidad mórbida (> 40 kg/m2). Se les realizó prueba de caminata de 6 minutos, se acotaron variables demográficas y antecedentes personales patológicos. Se analizaron las categorías de IMC con ANOVA de una vía y ajuste de Bonferroni y los sexos con prueba t, ambos para grupos independientes y correlaciones de Pearson para las diversas variables. Una p < 0.05 fue considerada estadísticamente significativa. Resultados: Se estudiaron 480 sujetos de ambos sexos en cuatro grupos. Edad: hombres 43 ± 11 y mujeres 45 ± 10 años. Porcentaje diabetes mellitus (6.7%), hipertensión arterial (18.3%). Metros caminados hombres vs. mujeres por IMC (normal: 483 ± 56 vs. 449 ± 61; sobrepeso: 471 ± 55 vs. 441 ± 44; obesidad: 455 ± 70 vs. 421 ± 47; obesidad mórbida: 443 ± 49 vs. 403 ± 54; p < 0.05). Correlación IMC-metros caminados r: –0.446 (p < 0.0001). Conclusiones: Los metros caminados en la prueba de caminata de 6 minutos disminuyeron conforme incrementó el IMC. El sexo masculino caminó más metros en todas las categorías.

Abstract Introduction: Morbid obesity is associated with alterations in the ability to walk, however, the behavior of the 6-minute walk test in subjects with increases in body mass index is unknown. Objective: To describe the behavior of the 6-minute walk test in subjects with normal body mass index to morbid obesity. Methods: Through an analytical cross-sectional design, subjects of both genders from 18 to 60 years old with body mass index were studied: Normal (BMI: 18.5-24.9); overweight (BMI: 25-29.9); obesity (BMI: 30-39.9); morbid obesity (BMI: > 40) kg/m2. A 6-minute walk test was performed, demographic variables and pathological personal history were delimited. BMI categories were analyzed with one-way ANOVA and Bonferroni adjustment, and gender with t-test, both for independent groups, and Pearson's correlations for the various variables. Results: 480 subjects of both genders were studied in four groups. Age: men 43 ± 11 and women 45 ± 10 years old. Percentage diabetes mellitus (6.7%), arterial hypertension (18.3%). Meters walked men vs. women by body mass index (normal: 483 ± 56 vs. 449 ± 61; overweight: 471 ± 55 vs. 441 ± 44; obesity: 455 ± 70 vs. 421 ± 47; morbid obesity: 443 ± 49 vs. 403 ± 54, p < 0.05). Correlation body mass index-meters walked: r: -0.446 (p < 0.0001). Conclusions: Meters walked in the 6-minute walk test decreased as body mass index increased. The male gender walked more meters in all categories.

Objectives: The kynurenine (KYN) pathway has been attracting attention as a relevant pathway in schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). We conducted a systematic review and meta-analysis of studies examining KYN pathway metabolites from cerebrospinal fluid (CSF) samples in SZ, BD, and MDD. Methods: The PubMed and Scopus databases were systematically searched to identify peer-reviewed case-control studies published until April 2022 that assessed KYN metabolites, namely, tryptophan (TRP), KYN, kynurenic acid (KA), quinolinic acid (QA), and 3-hydroxykynurenine (3-HK), in subjects with SZ, BD, or MDD compared with healthy controls (HC). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The random effects model method was selected for comparison of standardized mean differences (SMD) between two groups. Results: Twenty-three articles met the inclusion criteria (k = 8, k = 8, k = 11, for SZ, BD, and MDD, respectively). In SZ, KA levels were increased (SMD = 2.64, confidence interval [CI] = 1.16 to 4.13, p = 0.0005, I2 = 96%, k = 6, n=384). TRP (k = 5) and KYN (k = 4) did not differ significantly. In BD, TRP levels (k = 7) did not differ significantly. The level of KA was increased in MDD (k = 2), but the small number of studies precluded evaluation of statistical significance. Finally, in MDD, although some studies tended to show an increased level of KYN in those with remission vs. decreased levels in those with current depression, no significant difference was found in any KYN metabolite levels. Similarly, an increased level of QA was found, but the number of studies (k = 2) was small. Conclusion: KA, which has possibly neuroprotective effects, is increased in SZ. QA, which has neurotoxic effects, may be increased in MDD. There were no alterations in BD. Alterations in the KYN pathway may occur based on population characteristics and mood states. Future studies should explore the utility of these metabolites as biomarkers.

RESUMEN La educación superior desempeña un papel relevante en la atención a los procesos de desarrollo territorial y local. La carrera de Licenciatura en Bioquímica y Biología Molecular (BBM) coordinada por la Universidad de La Habana, es una carrera nacional, y sus egresados cumplen una significativa labor en sus territorios de origen. Sin embargo, gran parte de ellos no regresa a sus provincias. Es importante para la carrera, considerar en el concepto de sostenibilidad, no solo el aspecto conceptual, sino también el económico-social y el desarrollo de iniciativas, para incentivar el compromiso de los estudiantes con su región. Este trabajo, a partir de entrevistas individuales a estudiantes, y del análisis de la ubicación y el desarrollo profesional de graduados de la carrera en instituciones científicas y Centros de Educación Superior, tuvo como objetivo proponer una estrategia que motive el compromiso de los egresados de mantenerse en su localidad, y así contribuir al desarrollo local en las esferas de la biomedicina y la biotecnología de sus territorios.

ABSTRACT The higher education system plays a relevant role in accomplishing the processes of territorial and local development. The University of Havana nationally coordinates the Bachelor in Biochemistry and Molecular Biology (BMB) degree, and their graduates carry out essential work for their territories of origin. However, most of BMB graduates do not return to their provinces. It is important for the Biochemistry and Molecular Biology career to consider in the concept of sustainability not only the conceptual aspect of this science, but also the economic and social aspects, and the development of initiatives to encourage the commitment of students with their region. This work, from the analysis of the placement and professional development of BBM graduates in scientific institutions and higher education centers and individual interviews with students, was aimed to propose a strategy for motivating the graduates’commitment with their territories, and thus contribute to the local development in the fields of biomedicine and biotechnology in their territories.

Abstract Objective: The aim of our study was to evaluate the expression of MMP-2 and MMP-9 as a prognostic factor in patients diagnosed with Hodgkin Lymphoma (HL). Methods: In the present study, 45 paraffin biopsies from patients up to 19 years old diagnosed with HL were used in two referral hospitals in the state of Pernambuco, Brazil. Risk groups were classified into favorable and unfavorable, according to Ann Arbor. The expression of matrix metalloproteinases 2 and 9 and their inhibitors was performed by immunohistochemistry (IHC). Data were analyzed using the GraphPad Prism 5 program. Results: MMP-2 intensity pattern was stronger (> 10% of the total field) in patients with stage III/ IV and B symptoms. MMP-2 showed an association with the risk group (p = 0.0388). That is, the stronger the MMP-2 marking, the greater the unfavorable risk. However, for MMP-9 there was no difference in the stronger intensity pattern in relation to stages I/II and III/IV, only in the presence of B symptoms. MMP-9 showed an association with B Symptoms (p = 0.0411). Therefore, patients with B symptoms have higher MMP-9 expression. Conclusion: Our results suggest that MMP-2 expression is associated with HL progression. While MMP-9 expression is related to the clinical worsening of these patients. However, further studies are needed to evaluate the exact role of these proteins in hematologic malignancies.

Crisis hotlines are direct communication systems, usually telephone-based, set up to prevent suicide. However, few studies have evaluated their effectiveness. The present study aims to perform a systematic review, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework, of the effectiveness of interventions through direct communication systems to reduce the number of suicides or suicide attempts. We searched the MEDLINE, Cochrane, SciELO, and ClinicaTrials.gov databases, and used the 2011 Oxford Centre for Evidence-Based Medicine Levels of Evidence classification. The literature search yielded 267 studies, of which 35 fulfilled the selection criteria. Although significant heterogeneity was found among studies, there is evidence that direct telephone interventions are effective when included in broader preventive protocols and provided by trained staff. Despite the limitations, which included heterogeneity of samples, designs, and outcome measures, we were able to design a protocol for the use of remote services to prevent suicide and suicide attempts. A hotline or similar system could be an effective intervention for broader suicide prevention programs. However, further research is necessary to specify which protocol components are key to enhance effectiveness. Systematic review registry number: PROSPERO CRD42020206517

Objective: Changes in the kynurenine pathway are recognized in psychiatric disorders, but their role in Alzheimer’s disease (AD) is less clear. We aimed to conduct a systematic review and meta-analysis to determine whether tryptophan and kynurenine pathway metabolites are altered in AD. Methods: We performed a systematic review and random-effects meta-analyses. Inclusion criteria were studies that compared AD and cognitively normal (CN) groups and assessed tryptophan or kynurenine pathway metabolites in cerebrospinal fluid or peripheral blood. Results: Twenty-two studies with a total of 1,356 participants (664 with AD and 692 CN individuals) were included. Tryptophan was decreased only in peripheral blood. The kynurenine-to-tryptophan ratio was only increased in peripheral blood of the AD group. 3-Hydroxykynurenine was decreased only in cerebrospinal fluid and showed higher variability in the CN group than the AD group. Kynurenic acid was increased in cerebrospinal fluid and decreased in peripheral blood. Finally, there were no changes in kynurenine and quinolinic acid between the groups. Conclusions: Our results suggested a shift toward the kynurenine pathway in both the brain and in the periphery, as well as a shift towards increased kynurenic acid production in the brain but decreased production in peripheral blood. In addition, our analysis indicated dissociation between the central and peripheral levels, as well as between plasma and serum for some of these metabolites. Finally, changes in the kynurenine pathway are suggested to be a core component of AD. More studies are warranted to verify and consolidate our results.

ABSTRACT Objective: We evaluated the protective effect of postpartum resilience (measured before the pandemic onset) on the prevalence of moderate to severe anxiety symptoms during the coronavirus disease (COVID-19) pandemic. Methods: The sample included 589 mothers from a longitudinal study in southern Brazil. Three months after delivery we assessed maternal resilience through the Resilience Scale (RS). The Generalized Anxiety Disorders 7-item (GAD-7) was used to assess anxiety symptoms during the COVID-19 pandemic. Results: The prevalence of severe to moderate anxiety symptoms in this sample was 28.4% (95% CI: 25.0; 32.0). Resilience showed to be a protective factor against moderate to severe anxiety symptoms during the pandemic (OR: 0.98; p<0.001). Conclusions: The results showed that postpartum resilience is a factor associated with lower odds of a more intense manifestation of anxiety during pandemic periods. Thus, strengthening resilience by reinforcing appropriate coping strategies can prevent mental health problems.

RESUMO Objetivo: Avaliou-se o efeito protetor da resiliência pós-parto (medida antes do início da pandemia) sobre a prevalência de sintomas de ansiedade moderados a graves durante a pandemia da doença por coronavírus (COVID-19). Métodos: A amostra incluiu 589 mães de um estudo longitudinal do Sul do Brasil. Três meses após o parto, avaliou-se a resiliência materna por meio da Resilience Scale (RS). O Generalized Anxiety Disorders 7-item (GAD-7) foi usado para medir os sintomas de ansiedade durante a pandemia de COVID-19. Resultados: A prevalência de sintomas de ansiedade moderados a graves nessa amostra foi de 28,4% (IC 95%: 25,0-32,0). A resiliência mostrou-se um fator protetor para os sintomas de ansiedade moderados a graves durante a pandemia (RC: 0,98; p<0,001). Conclusões: Os resultados revelaram que a resiliência pós-parto é um fator associado a menor chance de uma manifestação mais intensa da ansiedade durante os períodos pandêmicos. Dessa forma, fortalecer a resiliência, reforçando estratégias de enfrentamento apropriadas, pode prevenir problemas de saúde mental.

The study investigated the factors associated with the self-perception safety of dental students in clinical activities during the COVID-19 pandemic. This cross-sectional study was based on a semi-structured online (google forms) self-applied questionnaire, sent by e-mail to three private Dental Schools in Brazil. The variables were: 1) sociodemographic information; 2) questions about the measures adopted by dental schools before returning to clinical activities; 3) dental students’ self-perception of security; 4) the General Health Questionnaire. Data were submitted to Fisher’s exact test (p<0.05). Of the 294 eligible students, 97% were evaluated and 100% received previous specific biosafety training predominantly theoretical (72.16%) longer than one hour (51.55%). Most students (81.44%) felt secure performing clinical care during the COVID-19 pandemic. Students undergoing specific biosafety training for longer than one hour felt safer than those perfoming training for up to 1 hour (p=0.004). Students from schools where the aerosol-producing restriction was applied felt safer than those without restrictions (p=0.016). Women reported feeling less secure than men (p=0.046), and students who submitted to COVID-19 Specific Biosafety Training felt safer in clinical activities than those submitted to theoretical training only (p=0.011). Students from private universities presenting psychosomatic changes felt less secure in practicing clinical dental care activities (p=0.006). In conclusion, time-spent training in biosafety, restriction of the use of aerosol-producing procedures, and the gender of students were associated with the self-perception safety of students. Students with practical training felt safer in clinical activities for patients with COVID-19 than those who had only theoretical training.

While most patients with depression respond to pharmacotherapy and psychotherapy, about one-third will present treatment resistance to these interventions. For patients with treatment-resistant depression (TRD), invasive neurostimulation therapies such as vagus nerve stimulation, deep brain stimulation, and epidural cortical stimulation may be considered. We performed a narrative review of the published literature to identify papers discussing clinical studies with invasive neurostimulation therapies for TRD. After a database search and title and abstract screening, relevant English-language articles were analyzed. Vagus nerve stimulation, approved by the U.S. Food and Drug Administration as a TRD treatment, may take several months to show therapeutic benefits, and the average response rate varies from 15.2-83%. Deep brain stimulation studies have shown encouraging results, including rapid response rates (> 30%), despite conflicting findings from randomized controlled trials. Several brain regions, such as the subcallosal-cingulate gyrus, nucleus accumbens, ventral capsule/ventral striatum, anterior limb of the internal capsule, medial-forebrain bundle, lateral habenula, inferior-thalamic peduncle, and the bed-nucleus of the stria terminalis have been identified as key targets for TRD management. Epidural cortical stimulation, an invasive intervention with few reported cases, showed positive results (40-60% response), although more extensive trials are needed to confirm its potential in patients with TRD.

Electrical and magnetic brain stimulation techniques present distinct mechanisms and efficacy in the acute treatment of depression. This was an umbrella review of meta-analyses of randomized controlled trials of brain stimulation techniques for managing acute major depressive episodes. A systematic review was performed in the PubMed/MEDLINE databases from inception until March 2020. We included the English language meta-analysis with the most randomized controlled trials on the effects of any brain stimulation technique vs. control in adults with an acute depressive episode. Continuous and dichotomous outcomes were assessed. A Measurement Tool to Assess Systematic Reviews-2 was applied and the credibility of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation framework. Seven meta-analyses were included (5,615 patients), providing evidence for different modalities of brain stimulation techniques. Three meta-analyses were evaluated as having high methodological quality, three as moderate, and one as low. The highest quality of evidence was found for high frequency-repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation, and bilateral rTMS. There is strong clinical research evidence to guide future clinical use of some techniques. Our results confirm the heterogeneity of the effects across these techniques, indicating that different mechanisms of action lead to different efficacy profiles.

ABSTRACT Introduction: Left ventricular hypertrophy is a major problem among patients with high blood pressure worldwide; it is also related to various entities, which can be fatal. Objective: To evaluate the diagnostic performance of the Sokolow-Lyon index in precordial leads for left ventricular hypertrophy. Method: An observational, analytical and cross-sectional study of diagnostic means was carried out. One hundred and twenty-two patients admitted to the Departments of Internal Medicine, Nephrology and Neurology of the Hospital Militar Carlos J. Finlay (Havana, Cuba) were studied from January 2017 to March 2019, who underwent echocardiography and electrocardiogram. Results: There was a predominance of the population over 45 years old (77.9%), males (59.8%) and with high blood pressure (77.0%). A qualitative description of the Sokolow-Lyon electrocardiographic index for precordial leads was performed in the total number of the studied cases, and a prevalence of 71.3% of left ventricular hypertrophy was found. This voltage criterion showed high specificity (83%), high positive predictive values (85%) and positive likelihood ratio at 2.28. Conclusions: In admitted patients, where the prevalence of high blood pressure is elevated, the Sokolow-Lyon criterion presented high diagnostic usefulness for left ventricular hypertrophy as well as to confirm the cases that actually present it.

RESUMEN Introducción: La hipertrofia de ventrículo izquierdo constituye un gran problema entre los pacientes con hipertensión arterial a nivel mundial, además se relaciona con diversas enfermedades, las cuales pueden ser fatales. Objetivo: Evaluar el rendimiento diagnóstico del índice de Sokolow-Lyon en derivaciones precordiales para la hipertrofia de ventrículo izquierdo. Método: Se realizó un estudio de medios diagnósticos de tipo observacional, analítico y transversal. Se estudiaron 122 pacientes ingresados en los servicios de Medicina Interna, Nefrología y Neurología del Hospital Militar Carlos J. Finlay (La Habana, Cuba) de enero del 2017 a marzo del 2019, a los cuales se les realizó ecocardiograma y electrocardiograma. Resultados: Existió un predominio de la población mayor de 45 años (77,9%), del sexo masculino (59,8%) y con hipertensión arterial (77,0%). Se realizó una descripción cualitativa del índice electrocardiográfico de Sokolow-Lyon para precordiales en el total de casos estudiados y se encontró una prevalencia de hipertrofia ventricular izquierda de 71,3%. Este criterio de voltaje presentó una alta especificidad (83%), alto valor predictivos positivo (85%) y una razón de verosimilitud (likelihood ratio) positiva de 2,28. Conclusiones: En pacientes hospitalizados, donde la prevalencia de hipertensión arterial es elevada, el criterio de Sokolow-Lyon presentó alta utilidad diagnóstica para la hipertrofia de ventrículo izquierdo, así como para confirmar los casos que verdaderamente la padecían.