Dynamic Linkage between Aging, Mechanizations and Carbon Emissions from Agricultural Production.

The trend of aging is intensifying and has become a prominent population phenomenon worldwide. The aging population has an important impact on carbon emissions, but at present, there is little research on its ecological consequences, especially the relationship with agricultural carbon emissions. For a long time, China has been dominated by a scattered small-scale peasant economy. Currently, the aging population also means that the agricultural labor force will gradually become scarce, and the agricultural production will face reform. This article is intended to find the long-term impact of aging and mechanization on agricultural carbon emissions and construct a more comprehensive policy framework for sustainable development, hoping to contribute to environmental and ecological protection. The research sample in this article is from 2000 to 2019, covering 30 provinces (cities, autonomous regions) in China. We adopted methods and models including Fully Modified General Least Squares (FMOLS), Dynamic General Least Squares (DOLS), Panel Vector Autoregression (PVAR) model, etc., and used the Granger causality test to determine the causal relationship between variables. Results show that aging is the Granger cause of agricultural carbon emissions and agricultural mechanization. Agricultural carbon emissions and agricultural mechanization have a bidirectional causal relationship. In the short term, agricultural mechanization and aging both have made a great contribution to carbon dioxide emissions from agricultural production. However, in the long term, the impact of aging on agricultural mechanization is significantly negative. Therefore, it is generally beneficial to improve the environmental problems of agricultural production. Our research focuses on the latest background of population trends and global climate issues and finally provides suggestions and a theoretical basis for the formulation of government agricultural policies according to the research conclusions.

Preparation and evaluation of carboxymethyl chitosan-rhein polymeric micelles with synergistic antitumor effect for oral delivery of paclitaxel.

An amphiphilic carboxymethyl chitosan-rhein (CR) conjugate was prepared, characterized, and evaluated as a potential carrier material for oral delivery of paclitaxel (PTX). CR conjugate self-assembled in aqueous environment into CR polymeric micelles (CR PMs). The drug loading capacity and entrapment efficiency of PTX-loaded CR PMs were 35.24 ± 1.58% and 86.99 ± 12.26%, respectively. Pharmacokinetic results indicate that PTX-loaded CR PMs could significantly enhance the oral bioavailability of PTX. Confocal imaging of intestinal sections verified many of CR PMs were absorbed as whole through the intestinal membrane. The cytotoxicity assays in Caco-2 cells and in vivo antitumor efficacy showed that PTX-loaded CR PMs had a stronger antitumor efficacy. A synergistic antitumor effect between CR conjugate and PTX was proven in MCF-7 cells and antitumor efficacy studies. The investigation of CR conjugate developed in this study showed that CR PMs are promising for oral delivery of water-insoluble antitumor drugs.