Half sphere exposure Half sphere exposure Half Sphere Exposure (HSE) is a protein solvent exposure measure that was first introduced by . Like all solvent exposure measures it measures how buried amino acid residues are in a protein. It is found by counting the number of amino acid neighbors within two half spheres of chosen radius around the amino acid. The calculation of HSE is found by dividing a contact number (CN) sphere in two halves by the plane perpendicular to the Cβ-Cα vector. This simple division of the CN sphere results in two strikingly different measures, HSE-up and HSE-down. HSE-up is defined
What Is This Thing Called Love? (short story) with aliens and sex. According to Asimov the article was mostly based on "Marvel" since its contents had been the raciest. Cele Goldsmith Lalli, editor of "Amazing Stories", requested a satire of the "Playboy" article. Asimov set out to write a story telling how a sex-interested alien and humans might "really" interact. The story appeared in the March 1961 issue of "Amazing" as "Playboy and the Slime God", but when Asimov included it in his 1969 collection "Nightfall and Other Stories" he retitled it "What Is This Thing Called Love?" Goldsmith Lalli rewrote the story's last three paragraphs, a change