Macroscale Superlubricity Induced by MXene/MoS2 Nanocomposites on Rough Steel Surfaces under High Contact Stresses.

Toward the goal of achieving superlubricity, or near-zero friction, in industrially relevant material systems, solution-processed multilayer Ti3C2Tx-MoS2 blends are spray-coated onto rough 52100-grade steel surfaces as a solid lubricant. The tribological performance was assessed in a ball-on-disk configuration in a unidirectional sliding mode. The test results indicate that Ti3C2Tx-MoS2 nanocomposites led to superlubricious states, which has hitherto been unreported for both individual pristine materials, MoS2 and Ti3C2Tx, under macroscale sliding conditions, indicating a synergistic mechanism enabling the superlative performance. The processing, structure, and property correlation were studied to understand the underlying phenomena. Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy revealed the formation of an in situ robust tribolayer that was responsible for the performance at high contact pressures (>1.1 GPa) and sliding speeds (0.1 m/s). This report presents the lowest friction obtained by either MoS2 or MXene or any combination of the two so far.

Advanced usage of Ti3C2Tx MXenes for photothermal therapy on different 3D breast cancer models.

Globally, breast cancer is the most diagnosed invasive cancer among women. Current therapies (e.g., chemotherapy) show numerous limitations due to the lack of selectivity and involved side effects, which urgently asks for novel approaches with enhanced tumor-killing efficacy. We previously demonstrated that MXenes, new bioactive nanomaterials with promising photophysical properties, are capable to increase the efficiency of the targeted breast cancer photothermal therapy (PTT). In this work, we investigated the effect of few- and multi-layer Ti3C2Tx MXenes mediated-PTT on two different 3D reliable breast cancer models such as conventional and bio-printed spheroids. We performed PTT on both cancer models using a non-toxic MXene concentration of 50 µg/mL. After PTT, a significant reduction in the cell viability along with a notable increase in reactive oxygen species (ROS) was observed. Moreover, we studied the effect of PTT on the migration of macrophages and endothelial cells toward cancer regions in both 3D models. Our results indicate that PTT mediated by both few- and multi-layer MXenes significantly modulates the tumor progression through cells' death by increasing the temperature, which holds particularly true for the bio-printed model.

ENEMDU Ecuador: estudio de la percepción de la seguridad y salud, 2018 / ENEMDU Ecuador: Study of the perception of health and safety, 2018

Resumen Introducción: a partir de la Encuesta Nacional de Empleo, Desempleo y Subempleo (ENEMDU), realizada por el Instituto Nacional de Estadísticas y Censos de Ecuador (INEC) en junio 2018, que representa uno de los instrumentos estadísticos más importantes para conocer la situación laboral en el país, se realiza el presente estudio. Objetivo: describir y analizar la percepción de la seguridad y salud, asociadas a características socio-demográficas y laborales en Ecuador. Metodología: consistió en un estudio de tipo cuantitativo, descriptivo y transversal, se aplicó un muestreo probabilístico y se determinó que 28.636 personas cumplen con la condición de estar laborando actualmente; se utilizó el software SPSS para el desarrollo de frecuencias absolutas y relativas, y el cálculo de prueba chi-cuadrado. Resultados: el 3,7 % de los encuestados afirman que se les ha realizado un examen preocupacional y el 7,2 % afirman que se les ha realizado un examen periódico; a su vez, el 42 % ha sido informado sobre los riesgos en su trabajo y el 14 % ha sido capacitado sobre el riesgo al que está expuesto. Discusión: lo que indica un déficit de la gestión de seguridad y salud a nivel nacional. Conclusión: se pone en manifiesto la necesidad de identificar los factores de riesgos laborales y su impacto en la salud, que en conjunto a registros oficiales permitan conocer las realidades de las organizaciones para establecer nuevas políticas de seguridad y salud en el país.

Abstract Introduction: this study was carried out based on the National Survey of Employment, Unemployment and Underemployment (ENEMDU), conducted by the National Institute of Statistics and Censuses of Ecuador (INEC) in June 2018, which represents one of the most important statistical tools to know the labor situation in the country. Objective: To describe and analyze the perception of safety and health, associated with socio-demographic and work characteristics in Ecuador. Methodology: it consisted of a quantitative, descriptive and transversal research. A probabilistic sampling method was applied being 28.636 people who meet the condition of being working at this time. SPSS software was used for the development of absolute and relative frequencies and calculation of chi-square test. Results: the results show that 3.7 % of the respondents have had a pre-occupational exam and 7.2 % have been periodically examined; in turn, 42 % have been informed about the risks at work and 14% have been trained on the risk to which they are exposed. Discussion: these results indicate a deficit of Health and Safety Management at the national level, Conclusion: This work highlights the need to identify the factors of Occupational risks and their impact on health, which together with official records allow to know the realities of organizations to establish new health and safety policies in the country.