A widespread increase in intense phytoplankton blooms has been noted in lakes worldwide since the 1980s, with the summertime peak intensity amplifying in most lakes. Such blooms cause annual economic losses of multibillion USD and present a major challenge, affecting 11 out of the 17 United Nations Sustainable Development Goals. Here, we evaluate recent scientific evidence for hormetic effects of emerging contaminants and regulated pollutants on Microcystis sp., the most notorious cyanobacteria forming harmful algal blooms and releasing phycotoxins in eutrophic freshwater systems. This new evidence leads to the conclusion that pollution is linked to algal bloom intensification. Concentrations of contaminants that are considerably smaller than the threshold for toxicity enhance the formation of harmful colonies, increase the production of phycotoxins and their release into the environment, and lower the efficacy of algaecides to control algal blooms. The low-dose enhancement of microcystins is attributed to the up-regulation of a protein controlling microcystin release (McyH) and various microcystin synthetases in tandem with the global nitrogen regulator Ycf28, nonribosomal peptide synthetases, and several ATP-binding cassette transport proteins. Given that colony formation and phycotoxin production and release are enhanced by contaminant concentrations smaller than the toxicological threshold and are widely occurring in the environment, the effect of contaminants on harmful algal blooms is more prevalent than previously thought. Climate change and nutrient enrichment, known mechanisms underpinning algal blooms, are thus joined by low-level pollutants as another causal mechanism.

Low Levels of Contaminants Stimulate Harmful Algal Organisms and Enrich Their Toxins.

Applications of the hormesis concept in soil and environmental health research

http://sioc-journal.cn/Jwk_hxxb/EN/article/downloadArticleFile.do?attachType=PDF&id=349257

High-Performance Flexible Photonic Synapse Transistors Based on a Bulk Composite Film of Organic Semiconductors with Complementary Absorption

The rhombohedral α-GeTe can be approximated as a slightly distorted rock-salt structure along its [1 1 1] direction and possesses superb thermoelectric performance. However, the role of such a ferroelectric-like structural distortion on its transport properties remains unclear. Herein, we performed a systematic study on the crystal structure and electronic band structure evolutions of Ge1-xSnxTe alloys where the degree of ferroelectric distortion is continuously tuned. It is revealed that the band gap is maximized while multiple valence bands are converged at x = 0.6, where the ferroelectric distortion is the least but still works. Once undistorted, the band gap is considerably reduced, and the valence bands are largely separated again. Moreover, near the ferro-to-paraelectric phase transition Curie temperature, the lattice thermal conductivity reaches its minima because of significant lattice softening enabled by ferroelectric instability. We predict a peak ZT value of 2.6 at 673 K in α-GeTe by use of proper dopants which are powerful in suppressing the excess hole concentrations but meanwhile exert little influence on the ferroelectric distortion. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/eem2.12535

Janaína Buchweitz e Silva

Papers

Unveiling structural characteristics for ultralow resistance drift in BiSb-Ge2Sb2Te5 materials for phase-change neuron synaptic devices

Synergistic toxicity to the toxigenic Microcystis and enhanced microcystin release exposed to polycyclic aromatic hydrocarbon mixtures

Kirkendall effect induced ultralow thermal conductivity yields enhanced thermoelectric properties in Mg–Zn–Sb alloys

Unveiling structural characteristics for ultralow resistance drift in BiSb-Ge2Sb2Te5 materials for phase-change neuron synaptic devices

Decoupling opposed thermoelectric properties