We report the rational control of the nanostructure and surface morphology of a polyamine@silica nanoribbon-based hybrid nanograss film, which was generated by performing a biomimetic silica mineralization reaction on a nanostructured linear polyethyleneimine (LPEI) layer preorganized on the inner wall of a glass tube. We found that the film thickness, size and density of the nanoribbons and th...

Considerable research has been directed toward identifying the mechanisms involved in biosilicification to understand and possibly mimic the process for the production of superior silica-based materials while simultaneously minimizing pollution and energy costs. Molecules isolated from diatoms and, most recently sponges, thought to be key to this process contain polyamines with a propylamine ba...

Herbivory of microzooplankton is an emerging key factor of diatom mortality in the ocean. As part of the microbial loop, protozoan grazers also feed on bacteria that accelerate the degradation of diatom detritus. The potentially pivotal effect of microzooplankton grazing on Si(OH)(4) recycling was investigated with cultures of single-celled diatoms, Thalassiosira pseudonana and Chaetoceros grac...

Many plants, including grasses and some important human food sources, accumulate, and precipitate silica in their cells to form opaline phytoliths. These phytoliths contain small amounts of organic matter (OM) that are trapped during the process of silicification. Previous work has suggested that plant silica is associated with compounds such as proteins, lipids, lignin, and carbohydrate comple...

Several geological features, including sedimentary cone-in-cone structures and percussion marks, may resemble impact-generated shatter cones. Especially inexperienced workers may mistake such features for impact deformation. In 1997, our group investigated an alleged occurrence of shatter cones in the Hamada area of southeastern Morocco and found that these are actually cone-in-cone structures,...

The epithermal high-sulphidation Cu-Au Chelopech deposit is characterized by a well-developed and well-traceable hydrothermal footprint manifested in the volcanic host rocks. economic ore mineralization embedded strong silicification, included among advanced argillic zone of alteration, smoothly transitioning to quartz-sericite alteration that evolves into widespread propylitics. accessible for...

In the Santander Massif of Eastern Cordillera Colombia, intense Pliocene to Holocene sulfide-rich gold mineralization occurs in a six kilometers long section La Baja fault zone, where it crosses partially migmatized gneisses and intrusions Triassic-Cretaceous quartz monzonites granites. These intrusives are mineralogically texturally similar neosome migmatites that they intrude. The as medium l...