[#insert2] Life on Earth uses about 25 of the 92 naturally occurring chemical elements, although just 4 of these elements—oxygen, carbon, hydrogen, and nitrogen—make up about 96 percent of the mass of living organisms. [#insert3] Thus, a first requirement for life might be the presence...
[#paragraph1]Petroleum is defined as a gaseous, liquid, and semisolid naturally occurring substance that consists chiefly of hydrocarbons (chemical compounds of carbon and hydrogen). Petroleum is therefore a term that includes both oil and natural gas. Petroleum is nearly always found in marine sed...
How does perihelion occur? Whenthe north pole is tilted away from the Sun, as it is now, the south pole is tilted toward it. As a result, summer is in full swing south of the equator even as northerners are bracing for a long winter. This morning at perihelion both hemispheres were ...
high-performance fibers. Meta-aramid fibers were first commercially applied in the early 1960s, with para-aramid fibers being developed in following decade. They are unique because their structures, characterized by polymer chains, are linked through powerful hydrogen bonds that efficiently transfer mech...
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Diatom frustule cleaning typically begins with the removal of organic matter, usually with a hydrogen peroxide (30% H2O2) leach in a water bath (up to 90 °C) which, depending on the organic matter abundance and composition, could last a period of hours to days. This is often preceded or...
although there is less available data for the latter. The mentioned compounds readily biodegrade aerobically, but their dispersion in the environment does not follow the same pattern; instead, they gradually sediment over time [82]. This phenomenon can occur, for instance, with outdoor-treated art...
Particles and fibres affect human health as a function of their properties such as chemical composition, size and shape but also depending on complex interactions in an organism that occur at various levels between particle uptake and target organ responses. While particulate pollution is one of the...
Particles and fibres affect human health as a function of their properties such as chemical composition, size and shape but also depending on complex interactions in an organism that occur at various levels between particle uptake and target organ responses. While particulate pollution is one of the...
Chemical space is large and nebulous, and the key consideration here is to incorporate functionality and chemical groups capable of making molecular interactions (e.g. a hydrogen-bond) with the protein of interest (Fig. 2). The design of libraries largely builds on decades of understanding of ...