An Attempt to Improve Certain Physical and Chemical Properties of Concrete through the use of Various Organic Polymers

Through the incorporation of various organic polymeric substances into several kinds of concrete mixes, we have attempted to produce a mixture which offered more than the usual resistance to corrosion by water and acid

Development of an interdisciplinary systems engineering program

Issued as Final report, Project no. J-1003Report prepared by Ronald O. Covaul

theta-Defensins: Cyclic Peptides with Endless Potential

theta-Defensins, the only cyclic peptides of animal origin, have been isolated from the leukocytes of rhesus macaques and baboons. Their biogenesis is unusual because each peptide is an 18-residue chimera formed by the head-to-tail splicing of nonapeptides derived from two separate precursors. theta-Defensins have multiple arginines and a ladder-like tridisulfide array spanning their two antiparallel beta-strands. Human theta-defensin genes contain a premature stop codon that prevents effective translation of the needed precursors; consequently, these peptides are not present in human leukocytes. Synthetic theta-defensins with sequences that correspond to those encoded within the human pseudogenes are called retrocyclins. Retrocyclin-1 inhibits the cellular entry of HIV-1, HSV, and influenza A virus. The rhesus theta-defensin RTD-1 protects mice from an experimental severe acute respiratory syndrome coronavirus infection, and retrocyclin- 1 protects mice from infection by Bacillus anthracis spores. The small size, unique structure, and multiple host defense activities of theta-defensins make them intriguing potential therapeutic agents

Expression, purification, crystallization and preliminary X-ray analysis of the cathelicidin motif of the protegrin-3 precursor

International audienc

Bridging Alone: Religious Conservatism, Marital Homogamy, and Voluntary Association Membership

This study characterizes social insularity of religiously conservative American married couples by examining patterns of voluntary associationmembership. Constructing a dataset of 3938 marital dyads from the second wave of the National Survey of Families and Households, the author investigates whether conservative religious homogamy encourages membership in religious voluntary groups and discourages membership in secular voluntary groups. Results indicate that couples’ shared affiliation with conservative denominations, paired with beliefs in biblical authority and inerrancy, increases the likelihood of religious group membership for husbands and wives and reduces the likelihood of secular group membership for wives, but not for husbands. The social insularity of conservative religious groups appears to be reinforced by homogamy—particularly by wives who share faith with husbands

Variations on a theme: bumblebee learning flights from the nest and from flowers

On leaving a significant place to which they will come back, bees and wasps perform learning flights to acquire visual information to guide their returns. The flights occur in different contexts, like their nest or a flower, which are functionally and visually different. The permanent and inconspicuous nest hole of a bumblebee worker is locatable primarily through nearby visual features; whereas a more transient flower advertises itself by its colour and shape. We compared the learning flights of bumblebees leaving their nest or a flower in an experimental situation in which the nest hole, flower and their surroundings were visually similar. Consequently, differences in learning flights could be attributed to the bee's internal state when leaving the nest or flower rather than to the visual scene. Flights at the flower were a quarter as long as those at the nest and more focussed on the flower than its surroundings. Flights at the nest covered a larger area with the bees surveying a wider range of directions. For the initial third of the learning flight, bees kept within about 5 cm of the flower and nest hole and tended to face and fixate the nest, flower and nearby visual features. The pattern of these fixations varied between nest and flower and these differences were reflected in the bees' return flights to the nest and flower. Together these findings suggest that the bees' learning flights are tuned to their inherent expectations of the visual and functional properties of nests and flowers