United Nations Economic Commission for Latin America and the Caribbean

FLASH radiotherapy, characterized by ultra-high dose rates (> 40 Gy/s), potentially spares normal tissues while maintaining antitumor efficacy (the FLASH effect). While electron and proton FLASH are explored, pulsed X-ray sources like plasma focus devices offer unique possibilities. Previous work has reported hyper-radiosensitivity in colorectal cancer cells exposed to ultra-high-dose-rate pulsed X-rays from a kilojoule plasma focus (PF) device, without significant effects on non-cancerous cells. This study further investigates the biological effects of ultra-high-dose-rate (~ 10⁷ Gy/min), low-total-dose pulsed X-rays generated by a PF-2 kJ device on colorectal cancer cell lines, focusing on DNA damage, cell cycle progression, and gene expression. Low-total-dose (~ 0.25 Gy), ultra-high-dose-rate pulsed X-rays (0.025 Gy/pulse, a total of 10 pulses, pulses temporally separated by 15–20 s) generated by a PF-2 kJ device induced a significant increase in the SubG1 population in HCT116 and DLD1 cells over 72 h, an effect indicative of apoptosis, which was not observed with conventional X-rays at similar total doses. In addition, pulsed X-rays induced apoptosis in radioresistant MCF-7 breast cancer cells. Whereas conventional X-rays did not cause a significant increase in double-strand breaks (DSBs), surrogate marker γ-H2AX and phosphor-P53(Ser15) signal were detected 30 min following pulsed X-ray exposure and persisted for up to 24 h, and no evidence of G2/M cell cycle arrest was detected in exposed cells. Gene expression analysis and preliminary transcriptomic data further suggest a DNA damage response leading to cell death and global change in general biological processes related to regulation of gene expression. Low-total-dose (~ 0.25 Gy), ultra-high-dose-rate pulsed X-rays generated by a PF-2 kJ device induce significant and sustained DNA damage (DSBs) leading to increased apoptosis in colorectal (HCT-116, DLD-1) and breast (MCF-7) cancer cells, compared to conventional X-rays. These effects, coupled with distinct changes in gene expression, suggest that ultra-high-dose-rate pulsed X-rays may overcomeradio-resistancee without eliciting a conventional DNA damage repair or cell cycle checkpoint response. These findings support the potential of PF-generated pulsed X-rays as a novel sourcof e radiotherapy modality and warrant further investigation, particularly in in vivo models, to assess clinical applicability and safety.

ABSTRACT This study develops and validates a multidimensional benchmarking instrument to evaluate the pedagogical quality of sNOOCs (social massive open online courses), integrating dimensions related to pedagogical design, usability, artificial intelligence (AI) and the metaverse. Through an instrumental validation study with a sequential-explanatory mixed methodology design. Using a sequential explanatory mixed-methods approach, a 24-item questionnaire was designed and administered in a peer assessment conducted by 135 postgraduate students at UNED (Spanish University of Distance Education), generating 937 assessments. The psychometric results confirm the excellent reliability of the instrument (Cronbach’s α = 0.97) and its structural validity, with a factor analysis explaining 77.6% of the variance. The findings reveal that pedagogical design is the highest-rated dimension, followed by usability and the quality of AI, showing a strong correlation among them. By contrast, the integration of the metaverse emerges as the main challenge, receiving the lowest rating and showing the greatest dispersion, indicating a lack of effective pedagogical alignment. The research validates peer assessment as a robust methodological strategy and offers a practical tool for continuous improvement of instructional design in advanced digital educational settings, while underlining the need for intentional pedagogical integration of emerging technologies.

El artículo presenta un ensayo crítico e interpretativo sobre Pensadores rebeldes, de Cristóbal Kay. Sistematiza, contextualiza y analiza las trayectorias intelectuales de Raúl Prebisch, Celso Furtado, André Gunder Frank, Theotônio dos Santos, Solon Barraclough y Willem Assies, según la caracterización que ofrece Kay. Se destacan el carácter heterodoxo y la originalidad de sus contribuciones al estructuralismo, la teoría de la dependencia, los estudios agrarios y el pensamiento crítico sobre el desarrollo, así como su distancia respecto del eurocentrismo y de los enfoques ortodoxos del subdesarrollo.

In Chile, despite high obstetric coverage and consolidated registration systems, there has been a stagnation in the reduction of maternal mortality, reflecting the need to identify social factors and determinants. These are often overlooked by traditional surveillance systems. To adapt and validate, through expert consensus, a verbal autopsy instrument based on the three delays model, with a gender and intercultural approach. Expert validation study using the Delphi method in three phases, carried out between June and October 2024. Forty experts in maternal health, epidemiological surveillance, gender, and interculturality participated. Seven criteria were evaluated: clarity, relevance, cultural relevance, socio-health relevance, regulatory relevance, and the incorporation of gender and intercultural approaches. The process sought to reach consensus to ensure the methodological and contextual quality of the instrument. The final instrument includes 95 items organized into six thematic blocks. An overall consensus of 85% was achieved on the evaluated criteria. The adaptation incorporated variables such as mental health, gender-based violence, ethnic identity, and perceived quality of care. Operational validation identified implementation, logistical, and ethical challenges, leading to a gradual implementation plan in regulatory, pilot, and national expansion phases. The instrument adapted and validated by experts offers a complementary tool for monitoring maternal mortality in Chile. Its comprehensive approach would allow identifying social and structural factors associated with maternal deaths, favoring more equitable and culturally relevant interventions aimed at preventing avoidable maternal deaths. Field validation is essential to assess the impact of its application.

IntroductionCutaneous squamous cell carcinoma (SCC) accounts for 20% of all skin cancers and its incidence continues to increase globally. It represents 75% of non-melanoma skin cancer (NMSC) mortality. Risk factors include ultraviolet radiation (UVR) exposure, advanced age, chemical exposure, fair skin types, and immunosuppression. While most human papillomavirus (HPV) infections are associated with the development of warts, a subgroup is potentially implicated in the development of cutaneous SCC. The prevalence of alpha, beta, and gamma-HPV in Chilean patients with hand SCCs has not been previously addressed. The objective of this study was to evaluate the presence of HPV and genotyping in hand SCC from Chilean patients.Materials and methodsAn observational, cross-sectional, descriptive study was conducted. Alpha (α), beta (β) and gamma (γ)-HPV detection was performed by conventional polymerase chain reaction (PCR) in paraffin-embedded tissue samples from 52 patients diagnosed with hand SCC from Santiago, Chile. HPV genotyping was carried out via direct amplicon sequencing by Sanger method.ResultsThe most frequent carcinoma site was the dorsum of the hands (52.5%). α-HPV was not detected in these specimens, whereas β-HPV and γ-HPV were detected in 25% of the analyzed samples. The most frequent genotypes found were β-HPV 100 (38%) and γ-HPV 178 (15%). Additionally, γ-HPV 101, 162, HPV-mSK_016, HPV-mSK_083, HPV-mSK_213 and HPV-mSK249nr genotypes were detected, none of which had been previously described in cutaneous SCC.Conclusionβ-HPV and γ-HPV are detectable in 25% of hand SCCs from Chilean patients. It is important to conduct prospective studies to better elucidate the role of these viruses in the development of this disease.

Este ensaio apresenta uma visão atual da realidade enfrentada por crianças e adultos com relação ao brincar. Ele considera premissas como a importância do brincar no desenvolvimento humano, as dificuldades que o brincar enfrenta quando as sociedades priorizam o trabalho ou o estudo e questões relacionadas ao fato de o brincar ser visto como perda de tempo e não ter um produto determinado e tangível para mostrar. O brincar é um direito da criança e, como tal, deve ser respeitado e incentivado; vemos hoje que certos adultos limitam a capacidade de brincar, afetando as enormes possibilidades de expressão de liberdade, exploração e, portanto, o prazer da alegria da descoberta e o uso da imaginação, elementos-chave na educação e no desenvolvimento humano.

Se usa un modelo de escasez económica para explicar los flujos de migración, la estructura familiar y el sistema de herencia de la población de Las Hurdes. La mobilidad social no es un factor que influya en la emigración: la gente de Las Hurdes emigra por la escasez de recursos de subsistencia, pero frecuentemente retorna para heredar y cultivar antiguos predios, reanudando su lugar dentro de la organización social. Las ceremonias maritales y la estrucutra del sistema de dotes reflejan también una preocupación central por la distribución de la tierra