In a relatively small but growing body of literature in political science and environmental studies, scholars debate the effect of democracy on environmental degradation. Some theorists claim that democracy reduces environmental degradation. Others argue that democracy may not reduce environmental degradation or may even harm the environment. Empirical evidence thus far has been limited and conflicting. This article seeks to address the democracy–environment debate. We focus on the effect of political regime type on human activities that directly damage the environment. Our discussion of the theoretical literature identifies different causal mechanisms through which democracy could affect environmental degradation. The empirical analysis focuses on the net effect of these competing mechanisms. We examine statistically the effect of democracy on five aspects of human‐induced environmental degradation—carbon dioxide emissions, nitrogen dioxide emissions, deforestation, land degradation, and organic pollution in water. We find that democracy reduces all five types of environmental degradation. While the substantive effect of democracy is considerable, it varies in size across different types of environmental degradation. We also find nonmonotonic effects of democracy that vary across the environmental indicators.
Clinical success of cancer radiotherapy is usually impeded by a combination of two factors, i.e., insufficient DNA damage and rapid DNA repair during and after treatment, respectively. Existing strategies for optimizing the radiotherapeutic efficacy often focus on only one facet of the issue, which may fail to function in the long term trials. Herein, we report a DNA-dual-targeting approach for enhanced cancer radiotherapy using a hierarchical multiplexing nanodroplet, which can simultaneously promote DNA lesion formation and prevent subsequent DNA damage repair. Specifically, the ultrasmall gold nanoparticles encapsulated in the liquid nanodroplets can concentrate the radiation energy and induce dramatic DNA damage as evidenced by the enhanced formation of γ-H2AX foci as well as in vivo tumor growth inhibition. Additionally, the ultrasound-triggered burst release of oxygen may relieve tumor hypoxia and fix the DNA radical intermediates produced by ionizing radiation, prevent DNA repair, and eventually result in cancer death. Finally, the nanodroplet platform is compatible with fluorescence, ultrasound, and magnetic resonance imaging techniques, allowing for real-time in vivo imaging-guided precision radiotherapy in an EMT-6 tumor model with significantly enhanced treatment efficacy. Our DNA-dual-targeting design of simultaneously enhancing DNA damage and preventing DNA repair presents an innovative strategy to effective cancer radiotherapy.
Both production of DNA damage and subsequent prevention of its repair are crucial in concluding the therapeutic outcome of radiotherapy (RT). However, nearly all current strategies for improving RT focus only on one of the two aspects and overlook the necessity of their combinations. In this work, we introduce a concept of DNAdual-targeting nanomedicine (NM) to simultaneously enhance DNA lesion formation and prevent the succeeding repair. Briefly, the cisplatin prodrug loaded in NM can form platinated DNA in cell nuclei, making DNA more vulnerable to the ionizing radiation generated by RT. Concomitantly, the spatial-temporally codelivered vorinostat, a histone deacetylase inhibitor, prolongs the build-up of double-strand breaks and causes cell apoptosis en masse, probably due to the suppressed expression of DNA repair proteins. Furthermore, this nanoplatform is suitable for fluorescence and magnetic resonance imaging techniques, enabling accurate trafficking of the NM as well as reliable real-time imaging-guided precision RT. Finally, results from in vitro and in vivo jointly reveal that this dualaction system attains a remarkably enhanced radiotherapeutic outcome. In conclusion, our imaging-guided DNA-dual-targeting design represents a novel strategy for efficient cancer precision RT.
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