Effect of synthesis temperature on crystallinity, morphology and cell viability of nanostructured hydroxyapatite via wet chemical precipitation method: Effect of temperature on hydroxyapatite properties

Hydroxyapatite (HA) is the main natural mineral constituent of bones and is a good alternative for biomedical applications because it is osteoconductive, non-allergenic, and non-carcinogenic, which ensures high biocompatibility. A commonly used method for obtaining hydroxyapatite is the wet route, which is simple and low-cost, produces only water as a final residue, and provides HA with a crystallinity comparable to that of bone tissue, which favors its biocompatibility. Therefore, the objective of this work is to synthesize hydroxyapatite via the wet chemical precipitation method at different temperatures (4°C, 30°C, 50°C, or 70°C) to observe the influence of temperature on crystallinity, morphology, and cytotoxicity. The results of X-ray diffraction show that all syntheses resulted in pure hydroxyapatite, while increasing the temperature led to higher crystallinity (10.6% to 56.2%) and the crystal size was slightly affected. The increase in temperature changed the particle shape from irregular to needle-like. Cell viability was tested by PicoGreen® in VERO cells for samples at concentrations of 30 and 300µg/mL, and the samples synthesized at 4°C, with lower crystallinity, caused less DNA damage to cells compared to the negative control. &nbsp

Mental health outcomes in frontline healthcare workers in Brazil during the COVID-19 epidemic: results of an online survey in four regions using respondent-driven sampling (RDS)

National Institute of Science and Technology for Health Technology Assessment (IATS) (CNPQ Project: 465518/2014-1), and MCTIC/CNPq/FNDCT/MS/ SCTIE/Decit (MCTIC/CNPq/FNDCT/MS/SCTIE/Decit N◦ 07/2020).Federal University of Rio Grande do Sul. Graduate Program in Epidemiology. Porto Alegre, RS, Brazil / National Institute of Science and Technology for Health Technology Assessment. Porto Alegre, RS, Brazil.Federal University of Rio Grande do Sul. Graduate Program in Epidemiology. Porto Alegre, RS, Brazil / National Institute of Science and Technology for Health Technology Assessment. Porto Alegre, RS, Brazil.Federal University of Ceará. Department of Community Health. Fortaleza, CE, Brazil.Federal University of Ceará. Department of Community Health. Fortaleza, CE, Brazil / Tulane University School of Public Health and Tropical Medicine. New Orleans, Louisiana, USA.Fortaleza University. Graduate Program in Public Health. Fortaleza, CE, Brazil.Federal University of Rio Grande do Sul. Graduate Program in Epidemiology. Porto Alegre, RS, Brazil / National Institute of Science and Technology for Health Technology Assessment. Porto Alegre, RS, Brazil.Pontifícia Universidade Católica do Rio Grande do Sul. Medical School. Porto Alegre, RS, Brazil.Hospital Moinhos de Vento. Porto Alegre, RS, Brazil.Hospital Moinhos de Vento. Porto Alegre, RS, Brazil.Federal University of Ceará. Department of Community Health. Fortaleza, CE, Brazil.Fundação Oswaldo Cruz. Insitute Aggeu Magalhaes. Recife, PE, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Santa Casa de São Paulo. School of Medical Sciences. São Paulo, SP, Brazil.Fundação Oswaldo Cruz. Insitute Aggeu Magalhaes. Recife, PE, Brazil.National Institute of Science and Technology for Health Technology Assessment. Porto Alegre, RS, Brazil / Hospital Moinhos de Vento. Porto Alegre, RS, Brazil / Hospital de Clínicas de Porto Alegre. Porto Alegre, RS, Brazil.Federal University of Rio Grande do Sul. Statistics Department. Porto Alegre, RS, Brazil / Hospital de Clínicas de Porto Alegre. Porto Alegre, RS, Brazil.Background: The COVID-19 pandemic overwhelmed health facilities and presented healthcare workers (HCWs) with a new infectious disease threat. In addition to a sanitary crisis, Brazil still had to face major political, economic, and social challenges. This study aimed to investigate mental health outcomes in frontline HCWs in different regions of the country and at different epidemic times. We also sought to identify the main risk factors associated with these outcomes. Methods: A cross-sectional online survey using respondent-driven sampling was conducted to recruit physicians (n = 584), nurses (n = 997), and nurse technicians (n = 524) in 4 regions of Brazil (North, Northeast, Southeast, and South) from August 2020 to July 2021. We used standardized instruments to screen for common mental disorders (CMD)(SRQ-20), alcohol misuse (AUDIT-C), depression (PHQ-9), anxiety (GAD-7), and post-traumatic stress disorder (PTSD)(PCL-5). Gile’s successive sampling estimator was used to produce weighted estimates. We created a three-cluster data set for each HCW category and developed a hierarchical regression model with three levels: individual characteristics; workplace-related aspects; COVID-19 personal experience. The impact of the epidemic moment on the outcomes was also studied. Results: The prevalence of probable CMD was 26.8–36.9%, alcohol misuse 8.7–13.6%, depression 16.4–21.2%, anxiety 10.8–14.2%, and PTSD 5.9–8.0%. We found a stronger association between mental health outcomes and the following factors: history of psychiatric disorders, female gender, and clinical comorbidities (level 1); work overload and family isolation (level 2); sick leave (level 3). Epidemic variables, such as the number of deaths and trend of deaths by COVID-19, had almost no impact on the outcomes. Conclusion: An alarmingly high prevalence of depression and anxiety was found in Brazilian frontline HCWs. Individual factors were the most strongly associated with mental health outcomes. These findings indicate the need to develop programs that provide emotional support, identify professionals at risk and refer them to specialized treatment when necessar