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Fe-based MOFs (Fe-MOFs) are excellent photocatalysts and have synergy well with Fenton reagents relative to other MOFs. In this work, a series of uniformly covered NH2-Fe-MIL-88B@TpPa-1-COF composites were synthesized using an in-situ anchoring growth strategy, which used F127 as functional molecule to decorate NH2-Fe-MIL-88B nanoparticles to eliminate their surface electrostatic repulsion with Tp molecules during the subsequent coating procedure. Meanwhile, the -NH2 groups in the skeleton of NH2-Fe-MIL-88B could also be used as anchors to covalently connect TpPa-1-COF shell and migration channels for effective charge transfer. This uniformly covered core–shell structure would endow these composites with much more contact area and imine bond linkage between the Fe-MOFs core and COFs shell. Compared with the random packing structure, the uniformly covered Fe-MOF@COF-3 composite possessed a higher proportion of Fe2+ to Fe3+. As a result, the optimized Fe-MOF@COF-3 catalyst could achieve the highest photo-Fenton degradation efficiency of 93.9% for tetracycline hydrochloride (TC⋅HCl), which was much higher than 54.8% of pure NH2-Fe-MIL-88B. In addition, the uniform TpPa-1-COF shell could further effectively enhance the stability of NH2-Fe-MIL-88B by protecting Fe ions from leaching, and the toxicity of the water samples treated with our photo-Fenton degradation process declined obviously. All these merits will endow Fe-MOF@COF-3 photo-Fenton catalyst great potential application value as in the field of environmental governance. [ABSTRACT FROM AUTHOR]

Morphogens act in developing tissues to control the spatial arrangement of cellular differentiation. The activity of a morphogen has generally been viewed as a concentration-dependent response to a diffusible signal, but the duration of morphogen signalling can also affect cellular responses. One such example is the morphogen sonic hedgehog (SHH). In the vertebrate central nervous system and limbs, the pattern of cellular differentiation is controlled by both the amount and the time of SHH exposure. How these two parameters are interpreted at a cellular level has been unclear. Here we provide evidence that changing the concentration or duration of SHH has an equivalent effect on intracellular signalling. Chick neural cells convert different concentrations of SHH into time-limited periods of signal transduction, such that signal duration is proportional to SHH concentration. This depends on the gradual desensitization of cells to ongoing SHH exposure, mediated by the SHH-dependent upregulation of patched 1 (PTC1), a ligand-binding inhibitor of SHH signalling. Thus, in addition to its role in shaping the SHH gradient, PTC1 participates cell autonomously in gradient sensing. Together, the data reveal a novel strategy for morphogen interpretation, in which the temporal adaptation of cells to a morphogen integrates the concentration and duration of a signal to control differential gene expression. [ABSTRACT FROM AUTHOR]

Oyster reef habitats in estuarine areas are an important marine ecosystem globally. Due to the destruction of oyster reef habitats within the Luanhe River estuarine area, Bohai Sea, China, a local fisheries company created 2 km2 of artificial oyster reef habitats by deploying artificial reef blocks that provided a settling surface for a natural oyster population and conducted sea cucumber aquaculture. The aims of this study are to help fisheries managers to understand whether the ecosystem function of created oyster reef habitat is consistent throughout the seasons and to assess if the current fishing production policy which varies with seasons is reasonable. We presented steady-state trophic models in different seasons of a newly created artificial coastal oyster reef within the Luanhe River estuary to address the above issues. We concluded that seasonality is an important factor that needs to be carefully considered in the fisheries management of oyster reef ecosystems. [ABSTRACT FROM AUTHOR]