Switching voltage of an electrode alone can fine-tune the reactivity of a molecule — ScienceDaily

As we learned in chemistry class, chemical reaction occurs with the formation or cleavage of bonds between atoms. These chemical bonds form when atoms share or exchange electrons. The chemical reactivity can be controlled in several ways. Among them, the control of electronic property at the reaction site is generally employed. For example, electron-rich molecule prefers to react with a molecule that can readily accept electrons. Many atoms can form ‘functional groups’ that either donate or withdraw electrons and control the electron density distribution of a molecule. These functional groups can vary the electronic property of the molecule to speed up the intended chemical reaction. Commonly referred to as “inductive effect,” the electron-donating group pushes electrons to increase the electron density at the site where the reaction takes place. Conversely, electron-withdrawing group removes electrons and reduces the electron density of the reaction site.

In 1937, the American chemist Louis P.

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New Bio-Inspired Molecule Helps Concrete Resist Freeze Damage

Daily temperature swings can make water freeze and expand, then thaw and contract. Because concrete is porous and absorbs liquid, these changes often make its surface flake and peel. But researchers say a new process can help prevent such deterioration.

“The primary way in which we have resisted this freeze-thaw damage in the past was by using a technology that was developed in the 1930s, which was to put in tiny little air bubbles all throughout the concrete,” says Wil Srubar, a materials scientist and architectural engineer at the University of Colorado Boulder. These flexible bubbles absorb some pressure but also reduce concrete’s strength, make it soak up more water and require a finicky distribution process.

Srubar’s laboratory looked to the natural world, specifically “antifreeze” proteins that let some fish and bacteria endure frigid temperatures. In cells, these molecules cling to ice crystals’ surfaces and prevent them from growing too

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