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The study of lubricating oil is paramount for the optimal functioning of modern engines, and it has generated intensive research in the automotive industry. The aim is to improve the tribological properties of lubricants by including nanomaterials as additives in base oils. This article presents an exhaustive bibliographic review of the experiments carried out to optimize the tribological properties of nano-lubricants in order to identify the nanoparticles and experimental processes used and analyze the results obtained. The methodology adopted combines inductive and deductive elements. It begins with the formulation of a general theory on the application of nanoparticles in lubricants, followed by the collection of specific data on the conceptualization and preparation of nano-lubricants. A total of 176 articles focused on the application of nanoparticles in lubricants, especially to reduce the coefficient of friction, are reviewed. These works, with impact levels Q1 and Q2, delve into the application and are analyzed to review the obtained results. Most researchers worked with a nanoparticle concentration range of 0% to 1% by volume.

The objective is to evaluate the sleep characteristics of the staff working in a pediatric intensive care unit (PICU). They were asked to complete an anonymous survey concerning the characteristics and quality of their sleep, as well as the impact of sleep disturbances on their work and social life, assessed by Functional Outcomes of Sleep Questionnaire (FOSQ)-10 questionnaire. The response rate was 84.6% (85% females): 17% were doctors, 57% nurses, 23% nursing assistants, and 3% porters. 83.8% of them worked on fix shifts and 16.2% did 24-h shifts. 39.8% of workers considered that they had a good sleep quality and 39.8% considered it to be poor or bad. The score was good in 18.2% of the staff and bad in 81.8%. Night shift workers showed significantly worse sleep quality on both the objective and subjective evaluation. There was a weak concordance (kappa 0.267; p = 0.004) between the perceived quality of sleep and the FOSQ-10 evaluation. Sleep disorders affected their emotional state (30.2% of workers) and relationships or social life (22.6%). In conclusion, this study finds that a high percentage of health professionals from PICU suffer from sleep disorders that affect their personal and social life. This negative impact is significantly higher in night shift workers. Many health workers are not aware of their bad sleep quality.