Gordon Sproul

Van Arkel—Ketelaar triangles

Abstract An equilateral triangle with vertices designated metallic (M), ionic (I), and covalent (C) was introduced for pedagogical reasons many years ago by van Arkel and Ketelaar to qualitatively catalogue the types of chemical bonding organized by the Periodic Table. These triangles display a sequence of atoms from left to right (M to C) in the Periodic Table along one side and binary combinations of atoms along the other two sides (MI and IC), and we have systematically extended the information content and usefulness. By the positioning of atom pair combinations according to the sum and difference of configuration energies, CE (the average ionization energy of the valence electrons of an atom). This permits division of the triangle into regions corresponding to metallic, ionic, and covalent bonding and, in effect, quantifies the Periodic Table. Very recently Professor Gordon D. Sproul of the University of South Carolina, Beaufort, found literature references on several hundred binary compounds previously determined to be bound as metallic, ionic, or covalent compounds, and cleanly separated these into their known bonding categories by use of CE with plots which give essentially the same dividing lines that we have derived theoretically.

The structure of sickling deer type III hemoglobin by molecular replacement

A combination of oriented single-crystal electron microscopy and protein crystallography has been used to show that crystalline sickling deer hemoglobin molecules from Odocoileus virginianus [oxy fl-chain varianttype III, Hb(DIII)] pack to form a distorted honeycomb (hexagonal) structure with open solvent channels. This network of molecules, consisting of out-of-register anti-parallel strands (fibrils), bears an unmistakable relation to the hemoglobin fibers and aggregates found in human sickled cells. The crystal structure was solved by means of the rotation and translation functions, with data to 3-5/k resolution giving the current residual of 0.430. Oxyor cyanomet-Hb(DIII) crystallizes in space group C2 with a = 163.49 (3), b = 70.83 (2), c= 65.95 (2) A, fl = 94.15 (1) ° and Z = 4.

FreeMobility: Dynamic Localization Using GIS

This paper presents the design, implementation and evaluation of the FreeMobility location determination system. FreeMobility is a distributed system that allows Access Points (AP) or cellular towers to dynamically determine the location of a mobile user using the received signal strength and the mobility information (the direction and traveled distance) from the mobile. FreeMobility does not require the database calibration nor does it require special infrastructure or installation, and it is readily applicable to commodity mobile devices like laptops, PDAs and cell phones. Using both actual measurements (from the University of South Carolina Beaufort and a residential neighborhood in Columbia, South Carolina) and online data resources (from the war-driving community and other research groups), this paper presents detailed analysis and experimental results that explore practical issues in implementing the FreeMobility system. The results demonstrated that FreeMobility provides reliable location estimates and the best localization error is to within 1.0 meter. With the assistance of the Geographic Information System (GIS), FreeMobility is able to provide meaningful location attributes in addition to basic coordinates from most other systems. Also with GIS, FreeMobility does not require dense tower deployment in order to pinpoint a mobiles location.

Abiogenic Syntheses of Lipoamino Acids and Lipopeptides and their Prebiotic Significance

Researchers have formed peptide bonds under a variety of presumed prebiotic conditions. Here it is proposed that these same conditions would have also formed amide bonds between fatty acids and amino acids, producing phosphate-free amphipathic lipoamino acids and lipopeptides. These compounds are known to form vesicles and are ubiquitous in living organisms. They could represent molecules that provided protection by membranes as well as possibilities for proto-life metabolism . It is here demonstrated that when a fatty acid is heated with various amino acids, optimally in the presence of suitable salts or minerals, lipoamino acids are formed. Magnesium and potassium carbonates as well as iron (II) sulfide are found to be particularly useful in these reactions. In this manner N-lauroylglycine, N-lauroylalanine, N-stearoylalanine and several other lipoamino acids have been synthesized. Similarly, when glycylglycine was heated with lauric acid in the presence of magnesium carbonate, the lipopeptide N-lauroylglycylglycine was formed. Such compounds are proposed to have been critical precursors to the development of life.