Background: Age estimation is a vital aspect of the identification of an individual in forensic science. Teeth are one of the toughest structures in the human body and generally survive postmortem destruction. So, they can therefore be used more reliably than any other morphological or histological trait of the adult skeleton for estimating age. Aim of the study: The present work aimed to compare cementum incremental lines and aspartic acid racemization in age estimation among Egyptian subjects. Methods: Sixty-four subjects were assigned to two groups: males and females (each with 32 cases) to determine the effect of sex as a possible factor that might affect age estimation. For each group, in all subjects, age was estimated using histologic examination of ground, unstained section teeth by light and polarized microscopes, in addition to estimating the rate of aspartic acid racemization in the collagen of dentin by using the HPLC method. Results: There was a statistically significant correlation between each method of age estimation and chronological age. However, the strongest degree of correlation was observed for the racemization method, with a correlation coefficient of r = 0.99 (95% CI 0.98 to 0.99), followed by the light method, r = 0.94 (95% CI 0.90 to 0.96), and the polarized method, r = 0.93 (95% CI 0.88 to 0.95). Conclusions: Both methods, cementum incremental lines and aspartic acid racemization, could help in age estimation, but aspartic acid racemization is more reliable and accurate.

BACKGROUND: Stressful events like the COVID-19 pandemic can significantly impact education. Online learning has become crucial in educational institutions such as schools, institutes, and universities. AIM: This study’s purpose is to evaluate the psychological impact of online education on university students in Al-Madinah Al-Munawara. METHODS: A cross-sectional study using a self-administered survey is designed based on previous studies and frameworks to assess the psychological impact of online education. RESULTS: The present study showed that 21.8% of students always had trouble concentrating through the online learning process. About 23.4% had thoughts that their ability to study is impaired. About 19.8% found it difficult to work up. There is a negative impact on psychological health because 13.9% feel agitated, 20.8% become nervous, 20.6% become watchful and on guard, and 21.8% are usually distressed and find it difficult to relax. The sleep mode was also affected in 19.0% of participants, besides lack of interest which was noted in 17.7%. Hence, students experienced harmful and unwanted psychological impacts during the COVID-19 pandemic and lockdown period. CONCLUSION: Results of the present study suggest a relation between online education and the negative psychological status of students. Students experienced increased depression, anxiety, and stress that had a negative effect on their daily schedule and social well-being during the COVID-19 pandemic.

| This study aimed to measure the awareness and prevalence of ethics of animal research among undergraduate health college students in Saudi Arabia. Also, to estimate the prevalence of knowledge and identify the attitudes and beliefs among male and female students. To explore the possible solutions for these gaps of knowledge and areas to recommend these solutions to the concerned authorities. An observational cross-sectional study. This study was conducted at health colleges in Saudi Arabia. Telephone/face-to-face questionnaires were collected by data collectors using multistage and cluster sampling. There were four sections to the questionnaire, which were available in both Arabic and English. The questions in the first section focused on sociodemographic data. The second section asked questions concerning broad research ethics knowledge. In the third section, there were inquiries concerning the moral justifications for animal research arguments. The last section asked about general opinions about animal research. Data were analyzed using the Statistical Package for Social Science (SPSS) version 21.0 (SPSS, Chicago, IL, USA). Categorical variables were identified as frequencies and percentages using the Chi-squared test. Results: The results showed that most participants (89.6%) knew about the ethics of research, and the highest source of knowledge was the college curriculum (44.7%). There was a statistically significant difference in overall knowledge among the age groups, with students above 22 years having the highest mean knowledge. About animal research, most participants agreed that animal research has great benefits for humans (80.7%). Unexpected findings that 39% believed that animal research should be conducted in favor of human benefits even if it causes harm to animals. The study found that a considerable number (75.5%) of participants favored the use of animals in scientific research. There was a statistically significant increase (P ≤ 0.05) in those who accepted the use of animals as they got older. Binary multivariate logistic regression analysis showed that females and those in the medicine specialty were significant predictors of opinions on animal research. Linear regression analysis showed that age and source of knowledge were significant predictors of overall knowledge score on general knowledge of ethics in research. Conclusion: In conclusion, Saudi Arabia’s undergraduate health college students are aware of ethical issues related to animal research, but a sizable part expresses ambivalence. Older age correlates with higher knowledge scores, but there is a lack of recognition for critical ethical documents.