RESUMEN

We load the natural active molecules onto the spin film in an array using electrospinning techniques. The electrospun active molecular membranes we obtain in optimal parameters exhibit excellent capacity for scavenging radical. The reaction capacity of three different membranes for free radicals are shown as follow, glycyrrhizin acid membrane > quercetin membrane > α-mangostin membrane. The prepared active molecular electrospun membranes with a large specific surface area and high porosity could increase the interaction area between active molecules and free radicals. Additionally, it also has improved anti-airflow impact strength, anti-contaminant air molecular interference ability, and the ability to capture free radicals.

Asunto(s)

RESUMEN

Hydroxyl free radicals play the main role in atmospheric oxidative capacity. The formation of secondary fine particulate matter and the degradation of gaseous pollutants in the troposphere are dominated by hydroxyl free radical reactions. The harmful effect of particulate matters to human health is closely related to the free radicals distributed in the particulate matter phase. In this paper, the distribution of hydroxyl free radicals in near-ground ambient air was studied. The hydroxyl free radicals exist not only in the gaseous phase but also in the particulate phase, especially during heavy haze pollution. It is noteworthy that the concentration of hydroxyl free radicals in the particulate phase is about two times higher than that in the gaseous phase. The possible regeneration mechanisms are proposed. The excited electrons (e-) and holes (h+) formed e- - h+ pairs in particulate matters are identified to play a key role in promoting the regeneration of hydroxyl free radicals in particulate phase. Environmentally persistent free radicals in particulate phase could also further promote the chain reaction of free radicals and ultimately result in explosive regeneration in an environment that has been excited. The correlation between radical concentrations in gas species, particulate phases and particulate number concentration has been summary based on the actual monitoring site including Thermal power plant, Yumen street and Chemical street sites.

RESUMEN

Atmospheric particulate pollution in China has attracted much public attention. Occasionally, the particle number concentration increases sharply in a short time period, which is defined as a "particulate matter explosive increase". Heavy particulate matter pollution not only reduces visibility but also has an adverse effect on human health. Hence, there is an urgent need to discover the causes of particulate matter explosive increase. During this campaign, the particle number concentration and free radicals were measured at a tall building on the campus of Lanzhou University of Technology. Additionally, we examined a series of chemicals to reproduce the observed particulate matter explosive increase in a smog chamber to determine its potential factors. Then, we analyzed the mechanism of particulate matter explosive increase in the presence of free radicals. We found that, among the potential inorganic and organic sources analyzed, a mixture of organic and SO2 in the research region had a major effect on particulate matter explosive increase. Moreover, free radical oxidation has a large effect, especially in the formation of organic particulates.

Asunto(s)

RESUMEN

Attribution of biological robustness to the specific structural properties of a regulatory network is an important yet unsolved problem in systems biology. It is widely believed that the topological characteristics of a biological control network largely determine its dynamic behavior, yet the actual mechanism is still poorly understood. Here, we define a novel structural feature of biological networks, termed 'regulation entropy', to quantitatively assess the influence of network topology on the robustness of the systems. Using the cell-cycle control networks of the budding yeast (Saccharomyces cerevisiae) and the fission yeast (Schizosaccharomyces pombe) as examples, we first demonstrate the correlation of this quantity with the dynamic stability of biological control networks, and then we establish a significant association between this quantity and the structural stability of the networks. And we further substantiate the generality of this approach with a broad spectrum of biological and random networks. We conclude that the regulation entropy is an effective order parameter in evaluating the robustness of biological control networks. Our work suggests a novel connection between the topological feature and the dynamic property of biological regulatory networks.

Asunto(s)

RESUMEN

In a ferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction-diffusion system with reagent concentration gradients, we observed in the experiment a type of spirals with local waves forming groups. Here, we propose an interpretation of the wave grouping phenomenon. The wave grouping mechanism can be well explained in terms of the cooperation of the excitability gradient and the Doppler effect induced by spiral tip's meandering. In the simulation based on three-dimensional reaction-diffusion system using Oregonator model, spiral patterns analogous to the experiment observation are well reproduced when the parameter gradient in the z direction is introduced.