Microsaccades reflect attention shifts: a mini review of 20 years of microsaccade research.

Microsaccades are small, involuntary eye movements that occur during fixation. Since the 1950s, researchers have conducted extensive research on the role of microsaccades in visual information processing, and found that they also play an important role in human advanced visual cognitive activities. Research over the past 20 years further suggested that there is a close relationship between microsaccades and visual attention, yet lacking a timely review. The current article aims to provide a state-of-the-art review and bring microsaccades studies into the sight of attention research. We firstly introduce basic characteristics about microsaccades, then summarized the empirical evidence supporting the view that microsaccades can reflect both external (perception) and internal (working memory) attention shifts. We finally conclude and highlight three promising avenues for future research.

Synthesis and Surface Properties of Photoresponsive Gemini Surfactants: Implication for Remediating PAHs-Contaminated Groundwater.

The efficient utility of surfactants remains a daunting task for groundwater remediation. In this study, we have synthesized a conventional photoresponsive surfactant 4-[4-[(4-butylphenyl)azo]phenoxy]butyldimethylethylammonium bromide (AzoPB) and a gemini photoresponsive surfactant N1,N2-bis[4-[4-[(4-butylphenyl)azo]phenoxy]butyl]-N1,N2-tetramethylethane-1,2-diammonium bromide (AzoPBT) for solubilizing PAHs in groundwater. The two surfactants' photosensitivity, surface properties, and solubilization/release ability for phenanthrene (Phe) and acenaphthylene (Ace) were studied in detail. Under UV-light irradiation for 15-20 s, the two surfactants can be converted from trans to cis, while cis-to-trans isomerization can be achieved under visible-light irradiation for 1 min. Compared to AzoPB, AzoPBT exhibited strong surface properties such as lower critical micelle concentration (0.52 mM), surface tension (γ, 28.94 mN·m-1), minimum area (Amin, 1.72 × 10-8 nm2), and higher maximum adsorption (Γmax, 96.55 mol·m-2). The solubility of Phe and Ace in the AzoPBT aqueous solution (12.84 and 14.27 mg/L) was much higher than that in the AzoPB aqueous solution (7.51 and 8.77 mg/L) and gradually increased as the surfactant concentration increased in both aqueous solutions. Compared to AzoPB, gemini surfactant AzoPBT exhibited stronger solubilization ability. After four cycles of cis-trans isomerization conversion, AzoPBT could still reduce the hydrophobicity of Phe in natural groundwater, although the solubility of Phe decreased slightly. Additionally, the release capacity of AzoPBT was significantly higher than that of AzoPB during the cyclic solubilization-release process. The results indicated that gemini photoresponsive surfactants should be preferable to conventional photoresponsive surfactants for groundwater remediation due to their higher solubilization and release efficiency for Phe in the cyclic solubilization and release process, which can improve repair efficiency, minimize secondary pollution, and reduce remediation costs.

Simulation and risk assessment of typical antibiotics in the multi-media environment of the Yangtze River Estuary under tidal effect.

Frequent human activities in estuary areas lead to the release of a large number of antibiotics, which poses a great threat to human health. However, there are very limited studies about the influence of the special natural phenomena on the occurrence and migration of antibiotics in the environment. In this study, we simulated the migration and transformation of six typical antibiotics, including oxytetracycline (OTC), tetracycline (TC), norfloxacin (NOR), ofloxacin (OFX), erythromycin (ETM), and amoxicillin (AMOX), in the environmental media from 2011 to 2019 in the Yangtze River Estuary, by using the level III multi-media fugacity model combined with the factor of tides. The simulation results showed that the most antibiotics mainly existed in soil and sediment while erythromycin were found mainly in water. The concentrations of antibiotics in air, freshwater, seawater, groundwater, sediment, and soil were 10-23-10-25, 0.1-12 ng/L, 0.02-7 ng/L, 0.02-16 ng/L, 0.1-13 ng/g, and 0.1-15 ng/g respectively. Sensitivity analysis showed that the degradation rate (Km) and the soil-to-water runoff coefficient (Kl) were important model parameters, indicating that hydrodynamic conditions had a significant impact on the migration of antibiotics in various environmental phases in estuarine areas. Tide can enhance the exchange between water bodies and cause the transformation of the antibiotics from freshwater to seawater and groundwater, which improved the accuracy of the model, especially the seawater and soil phase. Risk assessments showed that amoxicillin, erythromycin, ofloxacin, and norfloxacin posed a threat to the estuarine environment, but the current source of drinking water did not affect human health. Our findings suggested that, when one would like to exam the occurrence and migration of antibiotics in environment, more consideration should be given to the natural phenomena, in addition to human activities and the nature of antibiotics.

Review on the contamination and remediation of polycyclic aromatic hydrocarbons (PAHs) in coastal soil and sediments.

The rapid economic and population growth in coastal areas is causing increasingly serious polycyclic aromatic hydrocarbons (PAHs) pollution in these regions. This review compared the PAHs pollution characteristics of different coastal areas, including industrial zones, commercial ports, touristic cities, aquacultural & agricultural areas, oil & gas exploitation areas and megacities. Currently there are various treatment methods to remediate soils and sediments contaminated with PAHs. However, it is necessary to provide a comprehensive overview of all the available remediation technologies up to date, so appropriate technologies can be selected to remediate PAHs pollution. In view of that, we analyzed the characteristics of the remediation mechanism, summarized the remediation methods for soil or sediments in coastal areas, which were physical repair, chemical oxidation, bioremediation and integrated approaches. Besides, this review also reported the development of new multi-functional green and sustainable systems, namely, micro-nano bubble (MNB), biochar, reversible surfactants and peracetic acid. While physical repair, expensive but efficient, was regarded as a suitable method for the PAHs remediation in coastal areas because of land shortage, integrated approaches would produce better results. The ultimate aim of the review was to ensure the successful restructuring of PAHs contaminated soil and sediments in coastal areas. Due to the environment heterogeneity, PAHs pollution in coastal areas remains as a daunting challenge. Therefore, new and suitable technologies are still needed to address the environmental issue.