Living organisms are exposed to a mixture of environmental stressors, and the resultant effects are referred to as multiple stressor effects. In the present work, we studied the multiple stressor effect in embryos of the zebrafish (Danio rerio) from simultaneous exposure to ionising radiation (alpha particles) and cadmium through quantification of apoptotic signals at 24 h postfertilisation (hpf) revealed by vital dye acridine orange staining. For each set of experiments, 32-40 dechorionated embryos were deployed, which were divided into four groups each having 8-10 embryos. The four groups of embryos were referred to as (1) the control group (C), which received no further treatments after dechorionation; (2) the Cd-dosed and irradiated group (CdIr), which was exposed to 100 μM Cd from 5 to 24 hpf, and also received about 4.4 mGy from alpha particles at 5 hpf; (3) the irradiated group (Ir), which received about 4.4 mGy from alpha particles at 5 hpf; and (4) the Cd-dosed group (Cd), which was exposed to 100 μM Cd from 5 to 24 hpf. In general, the CdIr, Ir and Cd groups had more apoptotic signals than the C group. Within the 12 sets of experimental results, two showed significant synergistic effects, one showed a weakly synergistic effect and nine showed additive effects. The multiple stressor effect of 100 μM Cd with ~4.4 mGy alpha-particle radiation resulted in an additive or synergistic effect, but no antagonistic effect. The failure to identify significant synergistic effects for some sets of data, and thus their subsequent classification as additive effects, might be a result of the relatively small magnitude of the synergistic effects. The results showed that the radiation risk could be perturbed by another environmental stressor such as a heavy metal, and as such a realistic human radiation risk assessment should in general take into account the multiple stressor effects.

Background Middle-aged and older adults are more vulnerable to hospitalization and mortality if they are infected with the COVID-19 virus. The present study investigates the longitudinal effects of subjective successful aging on middle-aged and older adults’ emotional and coping responses to the COVID-19 pandemic, and explores an underlying mechanism through perceived time limitation during the pandemic. Methods A sample of 311 Hong Kong Chinese middle-aged and older adults (Mage = 64.58, SD = 10.14, Range = 45–90 years) were recruited from an Adult Development and Aging Project and participated in a questionnaire study via an online platform or phone interview. Their levels of subjective successful aging, perceived time limitation, and emotional and coping responses to the pandemic were measured. Results The respondents who perceived themselves as more successful in aging process reported more positive and fewer negative emotions compared with their counterparts with lower levels of subjective successful aging. The mediation analysis showed that perceived time limitation could partially account for the effects of subjective successful aging on emotional and coping responses. Conclusions Findings of this study unveil the beneficial effects of subjective views of successful aging on emotional and coping responses to the pandemic through alleviating their perception of time limitation.

Volunteering is a popular activity among middle-aged and older adults as means to contribute to the society and to maintain personal health and wellbeing. While the benefits of volunteering have been well-documented in the current literature, it does not tend to distinguish between various types of volunteering activities. This cross-sectional study aims to compare the effects of instrumental (e.g. food preparation, fundraising) and cognitively demanding volunteering activities (e.g. befriending, mentoring) in a sample of 487 middle-aged and older Hong Kong Chinese adults. Participation in instrumental and cognitively demanding volunteering, life satisfaction, depressive symptoms, cognitive functioning and hand-grip strength were measured. The results of two-way between-subject robust analyses of variance demonstrated significant main effects of volunteering type and their interaction effect with age on life satisfaction and depressive symptoms. Comparisons among four volunteering groups (no volunteering, instrumental volunteering, cognitively demanding volunteering and both types) revealed that individuals engaging in instrumental volunteering exhibited lower life satisfaction and more depressive symptoms compared to those who engaged in cognitively demanding volunteering and those who did not volunteer at all. This detrimental pattern of instrumental volunteering was only seen in middle-aged adults, but not in older adults. Findings of this study revealed distinctive effects of two volunteering types, and provide valuable directions for designing future volunteering programmes.

More middle-aged and older adults are often encouraged to volunteer (Gray et al., 2012). However, the effects of various volunteering activities on physical, psychological and cognitive health remain unknown. This study thereby aims to investigate such effects and the moderating effect of age in such associations. Data of 501 middle-aged and older Hong Kong Chinese adults (Mage = 53.06, SD = 4.55; and Mage = 70.46, SD = 7.34, respectively; range = 45 – 96) from a survey on Adult Development and Aging were analysed. Engagements in instrumental (e.g., food preparation, fundraising) and cognitively demanding volunteering (e.g., counselling, mentoring), hand-grip strength, life satisfaction, depressive symptoms, and cognitive functioning were measured. Factorial ANOVA revealed significant main effects of age group and volunteering type (F = 29.71, and F = 3.96, respectively, ps < .001), and an interaction effect of age and volunteering type (F =1.80, p = .03) on health outcomes. Comparisons among the four volunteering types (no volunteering, instrumental volunteering, cognitively demanding volunteering, and both types) revealed that individuals engaging in cognitively demanding volunteering had better hand-grip strength, life satisfaction, and cognitive functioning, and lower depressive symptoms than those who engaged in instrumental volunteering (all ps < .05). The health outcomes of instrumental volunteering were even worse than those who did not volunteer at all. These patterns were more prevalent in the middle-aged adults than in the older adults. Findings of this study indicated the beneficial effects of cognitively demanding volunteering, providing valuable directions for future programs on volunteering.

Background: Middle-aged and older adults are more vulnerable to hospitalization and mortality if they are infected with the COVID-19 virus. The present study investigates the longitudinal effects of subjective successful aging on middle-aged and older adults’ emotional and coping responses to the COVID-19 pandemic, and explores an underlying mechanism through perceived time limitation during the pandemic. Methods: A sample of 311 Hong Kong Chinese middle-aged and older adults (Mage=64.58, SD=10.14, Range=45–90 years) were recruited from an Adult Development and Aging Project and participated in a questionnaire study via an online platform or phone interview. Their levels of subjective successful aging, perceived time limitation, and emotional and coping responses to the pandemic were measured.Results: The respondents who perceived themselves as more successful in aging process reported more positive and fewer negative emotions compared with their counterparts with lower levels of subjective successful aging. The mediation analysis showed that perceived time limitation could partially account for the effects of subjective successful aging on emotional and coping responses. Conclusions: Findings of this study unveil the beneficial effects of subjective views of successful aging on emotional and coping responses to the pandemic through alleviating their perception of time limitation.