ABSTRACT
The Cambrian explosion is represented by a rapid diversification of early animals in which the role of marine primary productivity remains obscure. In this study, we analyzed multiple geochemical data, including TOC, major, and trace elements, in the basinal Yuanjia section, South China. Covariations among TOC, P/Al, CuEF, and NiEF suggest that they could be taken as effective marine productivity proxies in the early Cambrian Nanhua Basin. The similarities of CdEF and Cd/Mo in the Nanhua Basin and modern upwelling settings suggest that they might be effective to track upwelling, where Cd and Mo were mainly controlled by plankton biomass and redox conditions, respectively. Our results indicate that CoEF and Co × Mn were invalid in evaluating upwelling because of the significant effects of water-column redox conditions on Co enrichments in the Nanhua Basin. The decreased TOC, P/Al, CuEF, and NiEF reflect a long-term decline in marine productivity from late age 2 to age 3. In comparison with the published results in the outer shelf (Jinsha, TZS drill core, YJK drill core, and GDM-1 well) and slope areas (TX-1 well), the fall in marine productivity might be common in the early Cambrian Nanhua Basin. Our results exhibit that the reduced marine productivity was accompanied by weakened upwelling, quiet hydrothermal activities, and enhanced local terrestrial fluxes, indicating that variations in marine productivity might be mainly driven by the development of upwelling in the early Cambrian Nanhua Basin. Comparison of marine productivity with fossil records suggests that food availability was sufficient to sustain the Cambrian explosion in the Nanhua Basin. We infer that marine productivity might indirectly stimulate early animal evolution through its significant impact on water-column oxygen levels in the early Cambrian Nanhua Basin.
ABSTRACT
The number of older adults is rising rapidly in China. Various concerns such as chronic diseases, financial inadequacy, and a feeling of loneliness have adversely affected the mental health of older adults, and this has become an important public health and social issue. To realize healthy aging, the Nineteenth National People's Congress of China put forth the Healthy China strategy, speeding up the promotion activities of mental health and pension measures, carrying out public welfare pension insurance for the entire population, and contributing to the mental health of older adults. This study used data from China Family Panel Studies. This study mainly uses the random effect estimation method (random effect, RE) and the feasible generalized least squares estimation method (FGLS) to control for heterogeneity to explore the impact of social and commercial pension insurance on the mental health of older adults, the moderating effect of social capital on pension insurance, and the mental health of older adults. The results showed that social pension insurance is proportional to the mental health of older adults, whereas commercial pension insurance is inversely proportional to mental health. Social capital had a significant moderating effect on pension insurance. When a country develops an aging economy, the emphasis on social capital helps make targeted industrial development suggestions. The government's expansion of insurance coverage is crucial for improving the mental health of older adults.
Subject(s)
Insurance , Social Capital , Humans , Aged , Mental Health , China/epidemiology , PensionsABSTRACT
The rapid diversification of early animals during the Ediacaran (635-541 Ma) and early Cambrian (ca. 541-509 Ma) has frequently been attributed to increasing oceanic oxygenation. However, the pattern of oceanic oxygenation and its relationship to early animal evolution remain in debate. In this review, we examine the redox structure of Ediacaran and early Cambrian oceans and its controls, offering new insights into contemporaneous oceanic oxygenation patterns and their role in the coevolution of environments and early animals. We review the development of marine redox models which, in combination with independent distal deep-ocean redox proxies, supports a highly redox-stratified shelf and an anoxia-dominated deep ocean during the Ediacaran and early Cambrian. Geochemical and modeling evidence indicates that the marine redox structure was likely controlled by low atmospheric O2 levels and low seawater vertical mixing rates on shelves at that time. Furthermore, theoretical analysis and increasing geochemical evidence, particularly from South China, show that limited sulfate availability was a primary control on the attenuation of mid-depth euxinia offshore, in contrast to the existing paradigm invoking decreased organic carbon fluxes distally. In light of our review, we infer that if oceanic oxygenation indeed triggered the rise of early animals, it must have done so through a shelf oxygenation which was probably driven by elevated oxidant availability. Our review calls for further studies on Ediacaran-Cambrian marine redox structure and its controls, particularly from regions outside of South China, in order to better understand the coevolutionary relationship between oceanic redox and early animals.
ABSTRACT
Development of successful formulations for poorly water-soluble drugs remains a longstanding critical and challenging issue in cancer therapy. The stearic acid-g-chitosan oligosaccharide (CSO-SA) micelles have been presented as potential candidates for intracellular antitumour agent delivery carrier. Herein, podophyllotoxin (PPT) loaded CSO-SA micelles (CSO-SA/PPT) were prepared by a dialysis method. The drug encapsulation efficiency could reach a higher level, the micellar size and the zeta potential increased with increasing charged amounts of drug. The cumulative release percentage of PPT drug from micelles enhanced with decreasing PPT content in the micelles. The cytotoxicities of CSO-SA/PPT micelles against human breast carcinoma (MCF-7) cells, human lung cancer cells (A549) and human hepatoma cell line (Bel-7402) were higher than that of free PPT formulation. The higher cytotoxicities were due to the faster PPT transport into tumour cells mediated by CSO-SA micelles. Overall, CSO-SA micelles might be a promising carrier for PPT delivery in cancer therapy.
