PTN from Leydig cells activates SDC2 and modulates human spermatogonial stem cell proliferation and survival via GFRA1.

BACKGROUND: Spermatogonial stem cells (SSCs) are essential for the maintenance and initiation of male spermatogenesis. Despite the advances in understanding SSC biology in mouse models, the mechanisms underlying human SSC development remain elusive. RESULTS: Here, we analyzed the signaling pathways involved in SSC regulation by testicular somatic cells using single-cell sequencing data (GEO datasets: GSE149512 and GSE112013) and identified that Leydig cells communicate with SSCs through pleiotrophin (PTN) and its receptor syndecan-2 (SDC2). Immunofluorescence, STRING prediction, and protein immunoprecipitation assays confirmed the interaction between PTN and SDC2 in spermatogonia, but their co-localization was observed only in approximately 50% of the cells. The knockdown of SDC2 in human SSC lines impaired cell proliferation, DNA synthesis, and the expression of PLZF, a key marker for SSC self-renewal. Transcriptome analysis revealed that SDC2 knockdown downregulated the expression of GFRA1, a crucial factor for SSC proliferation and self-renewal, and inhibited the HIF-1 signaling pathway. Exogenous PTN rescued the proliferation and GFRA1 expression in SDC2 knockdown SSC lines. In addition, we found downregulation of PTN and SDC2 as well as altered localization in non-obstructive azoospermia (NOA) patients, suggesting that downregulation of PTN and SDC2 may be associated with impaired spermatogenesis. CONCLUSIONS: Our results uncover a novel mechanism of human SSC regulation by the testicular microenvironment and suggest a potential therapeutic target for male infertility.

Consideraciones en la Renovación Curricular de la Carrera de Odontología en la Universidad de La Frontera, Chile

Dentro de la carrera de Odontología de la Universidad de La Frontera surge la necesidad de pasar por un proceso de renovación curricular. Para esto, se deben considerar tres ejes: la Mención en Prevención con la que cuenta el plan de estudios de Odontología, la coherencia con la legislación chilena y el Modelo Educativo de la Universidad en la formación y gestión de la carrera, y las metodologías de formación actualizadas. La Mención en Prevención se debe fortalecer para entregar una formación integral a los estudiantes, con énfasis en la responsabilidad social. La legislación chilena actualmente exige una revisión sistemática al plan de estudios de Odontología para cumplir con los estándares de calidad, y paralelamente la Universidad propone un Modelo Educativo que entrega un sello de calidad al trabajo de la casa de estudios, con el cual la carrera también debe alinearse. Por otra parte, la constante actualización de conocimientos disciplinares y pedagógicos en Odontología deben ser considerados y estudiados para un óptimo resultado en el proceso de renovación curricular, como así también la inclusión de las nuevas herramientas tecnológicas que se han desarrollado. Estos son ejes esenciales a considerar para generar impacto en educación en Odontología.

Within the dentistry program of the University of La Frontera, there is a need to undergo a process of curricular renewal. For this, three axes must be considered: Mention in Prevention in the Dentistry curriculum, the coherence with the Chilean legislation and the Educational Model of the University in the training and management of the program, and the updated training methodologies. The Mention in Prevention should be strengthened to provide comprehensive training to students, with emphasis on social responsibility. Chilean legislation currently requires a systematic review of the dentistry curriculum to comply with quality standards, and at the same time the University proposes an Educational Model that provides a quality seal for the work of the university, with which the program must also be aligned. On the other hand, the constant updating of disciplinary and pedagogical knowledge in Dentistry must be considered and studied for an optimal result in the process of curricular renovation, as well as the inclusion of new technological tools that have been developed. These are essential axes to consider in order to generate impact on education in dentistry.

Dietary supplementation of glutamine and glutamic acid on performance, intestinal morphometry, and carcass characteristics of broiler quails / Suplementação dietética de glutamina e ácido glutâmico sobre o desempenho, morfometria intestinal e características de carcaça de codornas de corte

This study evaluated the effect of dietary supplementation with glutamine and glutamic acid (Gln+Glu) on performance, intestinal morphometry, and carcass characteristics of broiler quails. Eight hundred birds were used, distributed in an entirely randomized design with 20 birds per experimental unit, and given five treatments (0.0; 0.2; 0.4; 0.6; and 0.8% Gln+Glu supplementation) with eight replicates. At 1-21 days of age, lower (P < 0.05) feed intake at 0.6 and 0.8% Gln+Glu supplementation and lower weight gain at 0.8% Gln+Glu supplementation compared to the control treatment were observed. By regression analysis, excluding the control treatment, there was an increasing linear effect (P < 0.05) for feed intake at 22 to 42 days of age. For intestinal morphometry, Gln+Glu supplementation only favored the villus development of the ileum (P < 0.05), giving it greater height at 0.2, 0.6, and 0.8% supplementation. Carcass characteristics, cuts, and edible viscera of the birds at 42 days were not affected (P > 0.05) by Gln+Glu supplementation levels. Thus, the glutamine and glutamic acid supplementation affected the performance and intestinal morphology of 21-d-old quails, decreasing feed intake and weight gain associated with the improvement of ileum morphology; conversely, performance and carcass characteristics at 42 days were not affected by amino acid supplementation.

Objetivou-se avaliar o efeito da suplementação dietética de glutamina e ácido glutâmico (Gln+Glu) sobre o desempenho, a morfometria intestinal e as características de carcaça de codornas de corte. Foram utilizadas 800 aves, distribuídas em delineamento inteiramente casualizado, com cinco tratamentos (0,0; 0,2; 0,4; 0,6 e 0,8% de suplementação de Gln+Glu) e oito repetições com 20 aves por unidade experimental. Na fase de um a 21 dias, constatou-se menor (P < 0,05) consumo de ração aos níveis de 0,6 e 0,8% de Gln+Glu e menor ganho de peso ao nível 0,8% de Gln+Glu em comparação ao tratamento controle; e, pela análise de regressão, excluindo-se o tratamento controle, houve efeito linear crescente (P < 0,05) para consumo de ração na fase 22 a 42 dias de idade. Para morfometria intestinal, a suplementação de Gln+Glu apenas favoreceu o desenvolvimento vilos do íleo (P < 0,05), conferindo-lhe maior altura aos níveis de 0,2; 0,6 e 0,8% de suplementação. As características de carcaça, cortes e vísceras comestíveis das aves aos 42 dias não foram afetadas (P > 0,05) pelos níveis de suplementação de Gln+Glu. Assim, a suplementação de glutamina e ácido glutâmico influenciou o desempenho e a morfometria intestinal de codornas de corte aos 21 dias de idade, promovendo redução do consumo de ração e do ganho, associado ao aumento morfométrico do íleo; por outro lado, o desempenho das aves e as suas características de carcaça aos 42 dias não foram afetados pela suplementação dos aminoácidos.

The impact of prolonging extinction on the ABC "super renewal" of instrumental responses in rats.

Two free operant conditioning experiments with rats examined the impact of conducting a large amount of extinction training on situations that enhance the ABC renewal effect (ABC super renewal). In Experiment 1, ABC renewal was strengthened by conducting acquisition in multiple contexts. All rats were trained to press a lever for food. One group was trained in one context, while the other two groups were trained in three contexts. Then, all rats received extinction in context B. For two groups this phase lasted 4 sessions, whereas it lasted 36 sessions for the other group. In Experiment 2, ABC renewal was strengthened by using a large number of acquisition sessions. Rats were trained to perform an operant response to obtain food in context A. One group received a moderate amount of training, while the rest of the rats received a larger number of acquisition sessions. Responses underwent extinction in context B. Two groups received 4 sessions, while 36 extinction sessions were used for the remaining group. In both experiments, rats were tested in context B (extinction context) and C (renewal context). Greater ABC renewal occurred both when acquisition training was conducted in multiple contexts (Experiment 1) and by increasing the amount of acquisition training (Experiment 2). Nevertheless, we found that conducting a large number of extinction sessions reduced ABC super renewal in Experiment 1 only.

Involvement of cortical projections to basolateral amygdala in context-induced reinstatement of ethanol-seeking in rats.

Ethanol is the most consumed substance of abuse in the world, and its misuse may lead to the development of alcohol use disorder (AUD). High relapse rates remain a relevant problem in the treatment of AUD. Exposure to environmental cues previously associated with ethanol intake could trigger ethanol-seeking behavior. However, the neural mechanisms involved in this phenomenon are not entirely clear. In this context, cortical projections to the basolateral amygdala (BLA) play a role in appetitive and aversive learned behaviors. Therefore, we aimed to evaluate the activation of the cortical projections from the prelimbic (PL), orbitofrontal (OFC), and infralimbic (IL), to the BLA in the context-induced reinstatement of ethanol-seeking. Male Long-Evans rats were trained to self-administer 10% ethanol in Context A. Subsequently, lever pressing in the presence of the discrete cue was extinguished in Context B. After nine extinction sessions, rats underwent intracranial surgery for the unilateral injection of red fluorescent retrograde tracer into the BLA. The context-induced reinstatement of ethanol-seeking was assessed by re-exposing the rats to Context A or B under extinction conditions. Finally, we combined retrograde neuronal tracing with Fos to identify activated cortical inputs to BLA during the reinstatement of ethanol-seeking behavior. We found that PL, but not OFC or IL, retrogradely-labeled neurons from BLA presented increased Fos expression during the re-exposure to the ethanol-associated context, suggesting that PL projection to BLA is involved in the context-induced reinstatement of ethanol-seeking behavior.

"Welcome to the Revolution": Promoting Generational Renewal in Argentina's Ni Una Menos.

Despite the global upsurge of youth-fueled mass mobilization, the critical question of why new generations may be eager to join established movements is under-explored theoretically and empirically. This study contributes to theories of feminist generational renewal in particular. We examine the longer-term movement context and more proximate strategies that have enabled young women to participate steadily in a cycle of protest, alongside more seasoned activists, due to a process of feminist learning and affective bonding that we call "productive mediation." We focus on the Argentine Ni Una Menos (Not One Less) massive yearly march, which, since its onset in 2015, demonstrates that feminist activists have achieved the sought-after goal of fostering a highly diverse mass movement. These large-scale mobilizations against feminicide and gender-based violence gain much of their energy from a strong youth contingent, so much so that they have been called "the Daughters' Revolution." We show that these "daughters" have been welcomed by previous generations of feminist changemakers. Drawing on original qualitative research featuring 63 in-depth interviews with activists of different ages, backgrounds, and locations across Argentina, we find that long-standing movement spaces and brokers, as well as innovative frameworks of understanding, repertoires of action, and organizational approaches, help to explain why preexisting social movements may be attractive for young participants.

Air circulation study inside and outside of urban buses induced by the opening of windows.

In this work, the external and internal airflow analysis in an urban bus is carried out through computational fluid dynamics. The research addresses the study of the internal flow to estimate the air change rate caused by the opening of windows. Two cases are considered: fully opening and partially opening the windows, and three bus speeds of 20, 40, and 60 km/h are assessed. The quantification of the air flow rate through the windows clearly displays that air enters through the rear windows and exits the bus through the front windows. This effect is explained by the pressure distribution in the outer of the bus, which causes the suction of the indoor air. At low bus speeds, the incoming air flow rate increases linearly with the speed, but the improvement is lower for high speeds. The theoretical air change time at 20 km/h is around 25.7 s, which is 9 times lower than expected by using HVAC systems. On the other hand, the estimation of the real air renewal time by solving a concentration shows that 40 s are needed to exchange 85% of the internal air of the bus. The research also assesses the effect of different levels of occupation inside the bus. Results are conclusive to recommend the circulation with full or partial window opening configurations in order to reduce the risk of airborne disease transmission.

Renovação de diluidor na tecnologia de sêmen de pequenos ruminantes / Extender renewal in the technology of small ruminants semen

O objetivo desta revisão foi compilar o que se tem na literatura a respeito do efeito da renovação de diluidor seminal, mediante centrifugação, na qualidade do sêmen refrigerado de caprinos e ovinos e no tempo de viabilidade seminal. Um dos primeiros estudos publicados com essa metodologia foi realizado com sêmen de cão, em 2005, por Verstegen et al., seguido por estudos em outras espécies, como a equina e suína. Nosso grupo de pesquisa desenvolveu alguns estudos com diferentes metodologias para avaliar a eficiência do método, a necessidade do uso da centrífuga refrigerada nesse processo, o uso de antioxidantes no diluidor para renovação e o tempo de renovação do diluidor em pequenos ruminantes.(AU)

The objective of this revision was to compile what exists in literature regarding the effect of seminal diluent renewal, through centrifugation, in the quality of cooled semen of goat and sheep and during seminal viability time. One of the first studies published with this methodology was performed with dog semen in 2005 by Verstegen et al., followed by studies in other species, such as equine and swine. Our research group developed some studies using different methodologies to evaluate method efficiency, the need to use a cooled centrifuge in this process, the use of antioxidants in the diluent for renewal and the diluent renewal time in small ruminants.(AU)

"Mi vida va a ser mucho mejor de lo que ha sido": estudio cualitativo sobre el vínculo entre regeneración de viviendas sociales, calidad de vida y salud / "My life will be much better than before": a qualitative study on the relationship between renewal of public housing, quality of life, and health / "Minha vida vai ser muito melhor do que antes": estudo qualitativo sobre a relação entre revitalização de moradias populares, qualidade de vida e saúde

El objetivo fue conocer el vínculo entre la vivienda, la salud y la calidad de vida en un contexto de regeneración de viviendas sociales, a partir de las experiencias y percepciones de sus habitantes, indagando en aquellos mecanismos que sostienen este vínculo antes de la regeneración, y en aquellos elementos derivados de la regeneración de la vivienda que se materializan en mejoras en la calidad de vida y potencialmente en la salud. Entre 1980 y los 2000, Chile enfrentó un masivo déficit cuantitativo de vivienda mediante una política que entregó más de 120.000 departamentos de vivienda social de bajo costo. Hoy en día, miles presentan severos problemas de habitabilidad, generando consecuencias negativas para sus habitantes, su salud y bienestar. Buscando dar solución al deterioro de la vivienda y el espacio público, el Ministerio de Vivienda y Urbanismo desarrolló el Programa de Regeneración de Conjuntos Habitacionales. El proyecto RUCAS busca evaluar los efectos del programa en la salud y evidenciar el impacto de intervenciones como éstas en poblaciones vulnerables en Latinoamérica. Se presentan resultados de 8 entrevistas y 2 grupos focales realizados en un conjunto de vivienda social en proceso de intervención en Viña del Mar. Usando análisis de contenido discursivo, los resultados muestran que la mala calidad material de la vivienda se percibe como dañino para la salud. La vivienda regenerada en tanto, promueve la recuperación y re-apropiación de los espacios y sus usos, la sociabilidad, nuevas prácticas saludables, sentimientos positivos y bienestar psicológico, emergiendo el componente psicosocial de la relación de las personas con su vivienda. Se concluye que la regeneración de la vivienda tiene el potencial de beneficiar a la salud física y mental por mecanismos tanto directos, devenidos de la materialidad renovada, como indirectos relacionados con las prácticas y experiencias en el espacio habitado.

The objective was to understand the link between housing, health and quality of life in a context of social housing regeneration, through the experiences and perceptions of its inhabitants, exploring the mechanisms that sustain this link before regeneration, and those elements derived from housing regeneration that result in improvements in quality of life and potentially in health. Between 1980 and the 2000s, Chile faced a massive quantitative housing deficit through a policy that delivered more than 120,000 low-cost social housing apartments. Today, thousands present severe habitability problems, generating negative consequences for their inhabitants, their health and well-being. Seeking to solve the deterioration of housing and neighborhoods, the Chilean Ministry of Housing and Urbanism developed the Housing Complex Regeneration Program. The RUCAS project seeks to evaluate the effects of the program on health and to assess the impact of interventions such as these on vulnerable populations in Latin America. We present results of 8 interviews and 2 focus groups conducted in a social housing complex in process of intervention in Viña del Mar. Using discursive content analysis, results show that the poor material quality of housing is perceived as harmful to health. Regenerated housing, on the other hand, promotes the recovery and re-appropriation of spaces and their uses, sociability, new healthy practices, positive feelings and psychological well-being, bringing to the fore the psychosocial component of people's relationship with their house. It is concluded that housing regeneration has the potential to benefit physical and mental health through both direct mechanisms, derived from the renovated materiality, and indirect mechanisms related to the practices and experiences of the lived space.

O objetivo foi compreender a relação entre habitação, saúde e qualidade de vida em um contexto de regeneração da habitação social, com base nas experiências e percepções de seus habitantes, investigando aqueles mecanismos que sustentam esta relação antes da regeneração, e aqueles elementos derivados da regeneração que se materializam em melhorias na qualidade de vida e potencialmente na saúde. Entre 1980 e os anos 2000, o Chile enfrentou um enorme déficit habitacional quantitativo através de uma política que proporcionou mais de 120.000 moradias sociais de baixo custo. Hoje, milhares apresentam graves problemas de habitabilidade, gerando consequências negativas para seus habitantes, sua saúde e bem-estar. Em busca de uma solução para a deterioração da habitação e seus bairros, o Ministério da Habitação e Urbanismo do Chile desenvolveu o Programa de Regeneração Habitacional. O projeto RUCAS procura avaliar os efeitos do programa sobre a saúde e o impacto de tais intervenções sobre populações vulneráveis na América Latina. São apresentados os resultados de 8 entrevistas e 2 grupos focais realizados em um complexo habitacional social no processo de intervenção em Viña del Mar. Usando análise discursiva de conteúdo, os resultados mostram que a má qualidade do material da habitação é percebida como prejudicial à saúde. A moradia regenerada, por outro lado, promove a recuperação e reapropriação dos espaços e seus usos, a sociabilidade, novas práticas saudáveis, sentimentos positivos e bem-estar psicológico, emergindo o componente psicossocial da relação das pessoas com sua moradia. Conclui-se que a regeneração habitacional tem o potencial de beneficiar a saúde física e mental tanto através de mecanismos diretos, decorrentes da materialidade renovada, como de mecanismos indiretos relacionados às práticas e experiências no espaço vivido.

Considerations for an urban health perspective in Chile from the "Quiero Mi Barrio" program

ABSTRACT OBJECTIVES To explore the perceptions of residents regarding their health and well-being in areas of personal and collective life, in relation to the experience of urban transformation originated by the Program for the Recovery of Neighborhoods in Chile "Quiero mi Barrio" (PQMB). METHODS Qualitative study conducted in eight neighborhoods, which were subject to interventions between 2012-2015, located in seven communes of Chile: Arica, Renca, Padre Las Casas, Villarrica, Castro, Ancud. Eighteen focus groups and 27 interviews were conducted between 2018 and 2019. A content analysis was carried out following the social determinants of health approach. RESULTS Material conditions of neighborhood infrastructure and psychosocial determinants were the main emerging and predominant categories in the residents' narratives. The new or improved infrastructure enhances sports and playing practices, as well as contributes to the feeling of safety and to the improvement of walkable spaces, support networks, socialization and dynamization of social organization. However, neglected aspects were visualized. The program had limitations of structural character that operate locally, such as aging, individual lifestyles that limit participation, and contexts of insecurity, especially in neighborhoods victims of drug trafficking. CONCLUSIONS The urban changes originated by the PQMB included improvements in neighborhood infrastructure and in the psychosocial environment, which are perceived by residents as beneficial aspects and promoters of collective wellbeing. However, global phenomena, and those related to the program, limit its scope and have repercussions on the perception of overall wellbeing of the residents in the neighborhoods. To go deeper into how this or other state neighborhood programs may or may not favor equitable access of different social groups, or which works may be better used by the groups, is an aspect that enhances the integral action with other sectors and local actors in the territories.

Effects of delay of reinforcement on ABA renewal.

ABA renewal was assessed by decreasing response rates by means of extinction or a 12-s delay of reinforcement in one experiment with rats. In a first phase, rats were trained to lever press for water in Context A. Rats were exposed to a second phase in Context B, where lever-pressing decreased for all rats; for one group of rats, lever-pressing decreased by means of extinction, while lever-pressing decreased by means of a 12-s delay for the other group. During a third phase, both groups were once again exposed to Context A with no reinforcer deliveries for lever-pressing. Once rats were exposed to the latter phase, renewal was observed for both groups. Results suggest that delay of reinforcement can be used as an alternative procedure to help reduce behavior and mitigate relapse.

The Regeneración Urbana, Calidad de Vida y Salud - RUCAS project: a Chilean multi-methods study to evaluate the impact of urban regeneration on resident health and wellbeing.

BACKGROUND: The available evidence of the health effects of urban regeneration is scarce In Latin America, and there are no studies focused on formal housing that longitudinally evaluate the impact of housing and neighborhood interventions on health. The "Regeneración Urbana, Calidad de Vida y Salud" (Urban Regeneration, Quality of Life, and Health) or RUCAS project is a longitudinal, multi-method study that will evaluate the impact of an intervention focused on dwellings, built environment and community on the health and wellbeing of the population in two social housing neighborhoods in Chile. METHODS: RUCAS consists of a longitudinal study where inhabitants exposed and unexposed to the intervention will be compared over time within the study neighborhoods (cohorts), capitalizing on interventions as a natural experiment. Researchers have developed a specific conceptual framework and identified potential causal mechanisms. Proximal and more distal intervention effects will be measured with five instruments, implemented pre- and post-interventions between 2018 and 2021: a household survey, an observation tool to evaluate dwelling conditions, hygrochrons for measuring temperature and humidity inside dwellings, systematic observation of recreational areas, and qualitative interviews. Survey baseline data (956 households, 3130 individuals) is presented to describe sociodemographics, housing and health characteristics of both cohorts, noting that neighborhoods studied show worse conditions than the Chilean population. DISCUSSION: RUCAS' design allows for a comprehensive evaluation of the effects that the intervention could have on various dimensions of health and health determinants. RUCAS will face some challenges, like changes in the intervention process due to adjustments of the master plan, exogenous factors -including COVID-19 pandemic and associated lockdowns- and lost to follow-up. Given the stepped wedge design, that the study capitalizes on within household changes over time, the possibility of adjusting data collection process and complementarity of methods, RUCAS has the flexibility to adapt to these circumstances. Also, RUCAS' outreach and retention strategy has led to high retention rates. RUCAS will provide evidence to inform regeneration processes, highlighting the need to consider potential health effects of regeneration in designing such interventions and, more broadly, health as a key priority in urban and housing policies.

Apego al Lugar e Identidad de Lugar en Barrios Patrimoniales / Place Attachment and Place Identity in Heritage Neighborhoods

Resumen La política internacional de protección del patrimonio mundial de la UNESCO se integró en las agendas de desarrollo nacional y local de los países de América Latina, gestionando proyectos de mejoramiento social y urbano en barrios históricos de las ciudades. Los efectos sociales, ambientales y económicos de estos procesos de patrimonialización de los lugares no han sido suficientemente analizados. En este sentido, y asumiendo una perspectiva psicoambiental, esta investigación describe y compara los índices de Apego al Lugar e Identidad de Lugar en habitantes de tres barrios de la ciudad de Valparaíso (n=544) (Chile) y dos en la ciudad de Quito (n=209) (Ecuador), que se encuentran ubicados en zonas catalogadas como Patrimonio de la Humanidad. A través de la aplicación de pruebas t de Student de comparación de medias y d de Cohen de valoración del tamaño del efecto, se observó que las personas que cuentan con mayor tiempo de residencia, que habitan barrios patrimoniales consolidados (donde las dimensiones socio-urbanas del entorno se encuentran mayormente intervenidas y desarrolladas) y que son propietarias de sus viviendas presentan puntajes más altos de Apego al Lugar e Identidad de Lugar. Se observó un nivel moderado de Apego de Lugar e Identidad de Lugar en los habitantes de los barrios patrimoniales de las ciudades de Valparaíso y Quito.

Abstract UNESCO's international policy for the protection of world heritage was integrated into the national and local development agendas of Latin American countries, managing social and urban improvement projects in historic city districts. The social, environmental and economic effects of these processes of heritage sites have not been sufficiently analyzed. In this sense and assuming a psycho-environmental perspective, this research describes and compares the indices of place attachment and place identity in 3 neighborhoods in the city of Valparaiso (n=544) and 2 in the city of Quito (n=209), which are located in areas classified as World Heritage. Through the application of Student t tests for comparing means and Cohen d tests for assessing the size of the effect, it was observed that people who have resided for longer periods of time, who live in consolidated heritage neighborhoods and who own their own homes, show higher scores in terms of place attachment and place identity. A moderate level of Place Attachment and Place Identity was observed in Valparaíso and Quito.

Positive affective states can play the role of context to renew extinguished instrumental behavior in rats.

In one experiment with rats, we examined whether positive affective states can serve as contexts in a between-subjects ABA renewal design using appetitive instrumental conditioning. Two groups of rats received training to press a lever for food where each acquisition session was preceded by administration of a tickling procedure (Context A) known to induce positive affective states. Then, lever pressing underwent extinction where rats received a pure handling treatment (Context B) before each session. During a final test session, we found stronger responding when the session was preceded by tickling (Group ABA) compared to handling (Group ABB), indicating an ABA renewal effect. Furthermore, test performance in Group ABB was not different from that in a third group where handling preceded acquisition sessions, and tickling extinction and test sessions (Group BAA), showing that tickling did not elevate instrumental responding during the test if it had been unrelated to initial acquisition. We discuss implications of our results for understanding the role of positive affective states in relapse of problem behavior.

Roles Played by YY1 in Embryonic, Adult and Cancer Stem Cells.

Accumulating evidence strongly indicates that the presence of cancer stem cells (CSCs) leads to the emergence of worse clinical scenarios, such as chemo- and radiotherapy resistance, metastasis, and cancer recurrence. CSCs are a highly tumorigenic population characterized by self-renewal capacity and differentiation potential. Thus, CSCs establish a hierarchical intratumor organization that enables tumor adaptation to evade the immune response and resist anticancer therapy. YY1 functions as a transcription factor, RNA-binding protein, and 3D chromatin regulator. Thus, YY1 has multiple effects and regulates several molecular processes. Emerging evidence indicates that the development of lethal YY1-mediated cancer phenotypes is associated with the presence of or enrichment in cancer stem-like cells. Therefore, it is necessary to investigate whether and to what extent YY1 regulates the CSC phenotype. Since CSCs mirror the phenotypic behavior of stem cells, we initially describe the roles played by YY1 in embryonic and adult stem cells. Next, we scrutinize evidence supporting the contributions of YY1 in CSCs from a number of various cancer types. Finally, we identify new areas for further investigation into the YY1-CSCs axis, including the participation of YY1 in the CSC niche.

Antecedentes y Consideraciones para la Renovación Curricular de la Carrera de Odontología de la Universidad de La Frontera, Chile / Background and Considerations for the Curricular Renewal of the Universidad de La Frontera, Chile Dental Degree

El presente artículo tiene por objeto aportar a la discusión y reflexión de los elementos teóricos-conceptuales que debe incorporar un proceso de renovación curricular, en este caso de la carrera de odontología de la Universidad de La Frontera, Chile. Este proceso debe orientarse hacia los nuevos contextos laborales que requiere hoy en día la odontología; estableciendo diseños y lineamientos claros para el desarrollo de los aprendizajes significativosde los estudiantes -con herramientas específicas, saberes interdisciplinarios y competenciastécnicas para la formación integral del profesional-y que a su v ez logre incorporar en todas sus etapas no tan a los estudiantes sino que también a su cuerpo docente. A fin que se logre una apropiación significativa entre todos los actores que participan, adquiriendo un compromiso y alineación con este desafío educativo-formativo, cuyo propósito es la mejora sustancial en la formación profesional odontológica en la región de La Araucanía, Chile.

The objective of this article is to contribute to the discussion and reflection of the theoretical- conceptual elements that should be incorporated in a process of curricular renewal. In this case, concerning the dental degree of the Universidad de La Frontera, Chile, this process should be geared toward the new work context required in the dental field nowadays. Clear designs and guidelines for the development of students' meaningful learning should be established. These should include Interdisciplinary knowledge, technical competences and specific educational tools in a comprehensive educational model for the students and subsequent professionals. Faculty as well as students ought to be included in all stages of this process. To accomplish this challenge in education and training requires a significant and absolute commitment on the part of all players involved, given that the objective is the substantial improvement of the dental professional education in the La Araucanía region.

The Body in the Mirror: Breast Cancer, Liminality and Borderlands.

Breast cancer is the most common cancer among women worldwide, and has a high mortality rate in northern Mexico. Its high rates present one of the principal health challenges of the California-Baja California border region. We employed "entangled" ethnography and interpretative phenomenological methods to explore breast cancer experiences among a group of Mexican immigrant women living on the US side of this border. We explore their trajectory from biographical disruption to biographical renewal. The entangled ethnographic approach includes reflections of the first author's experience as a genetic breast cancer survivor.

Renewal of nanofibers in Chlorella fusca microalgae cultivation to increase CO2 fixation.

This study explored strategies to increase the CO2 fixation ability of microalgae by renewing polymeric nanofibers in cultures of Chlorella fusca LEB 111. Nanofibers composed of 10% (w v-1) polyacrylonitrile (PAN)/dimethylformamide (DMF) containing 4% (w v-1) iron oxide nanoparticles (NPsFe2O3) were added to photobioreactors. The nanomaterial was renewed in the test cultures as follows: renewal only on day 7; renewal only on day 15; or renewal on both days 7 and 15 (i.e., double renewal). The highest biomass concentration (2.53 g L-1) and CO2 biofixation rate (141.5 mg L-1 d-1) were obtained by cultivating with double renewal, resulting in values 21.6% and 23% higher, respectively, than those obtained by cultivation without renewal. The application of nanofiber renewal in the cultivation of C. fusca LEB 111 shows the potential to increase CO2 biofixation, which may contribute to reducing the atmospheric concentrations of this main greenhouse gas intensifier.

Recaída de Variabilidade Operante com a Combinação dos Procedimentos de Renovação, Restabelecimento e Ressurgência / Relapse of Operant Variability with the Combination of the Renewal, Reinstatement, and Resurgence Procedures

Resumo O reaparecimento de variabilidade comportamental previamente extinta (i.e., recaída) foi investigado por meio dos modelos experimentais de renovação, restabelecimento e ressurgência. Na Fase de Treino (contexto A), ao serem expostos ao esquema múltiplo Lag 10 Acoplado, ratos apresentaram níveis similares de variabilidade nos dois componentes. Na Fase de Eliminação (contexto B), o esquema múltiplo Repetição Repetição promoveu a extinção da variabilidade. Na Fase de Teste (contexto A), com a suspensão da contingência de repetição e a liberação de reforços independentes, a variabilidade reapareceu no componente "Lag 10", anteriormente correlacionado com reforçamento da variação, mas não no componente "Acoplado". Esse resultado sugere que a variabilidade observada no teste de recaída corresponde à variabilidade operante, e não à variabilidade induzida pela extinção.

Abstract The reappearance of previously extinguished behavioral variability (i.e. relapse) was investigated with three experimental models: renewal, reinstatement and resurgence. In the Training Phase (context A), when exposed to the multiple Lag 10 Yoke schedule, rats showed similar levels of variability in both components. In the Elimination Phase (context B), the multiple Repetition schedule promoted the extinction of variability. In the Test Phase (context A), with the suspension of the repetition contingency and the delivery of response-independent reinforcers, variability reappeared in the "Lag 10" component, the one previously correlated with the reinforcement of variation, but not in the "Yoke" component. This result suggests that the variability observed in the relapse test corresponded to operant variability, and not to extinction-induced variability.