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Wilmington, NC, United States

The University of North Carolina at Wilmington, sometimes referred to as UNC Wilmington, is a public, co-educational university located in Wilmington, North Carolina, United States. UNCW enrolls approximately 14,000 undergraduate, graduate and doctoral students each year as part of the 17-campus University of North Carolina System. Wikipedia.


Almeida P.F.,University of North Carolina at Wilmington
Biochimica et Biophysica Acta - Biomembranes | Year: 2014

Recently, new and improved methods have been developed to measure translocation of membrane-active peptides (antimicrobial, cytolytic, and amphipathic cell-penetrating peptides) across lipid bilayer membranes. The hypothesis that translocation of membrane-active peptides across a lipid bilayer is determined by the Gibbs energy of insertion of the peptide into the bilayer is re-examined in the light of new experimental tests. The original hypothesis and its motivation are first revisited, examining some of the specific predictions that it generated, followed by the results of the initial tests. Translocation is understood as requiring two previous steps: binding and insertion in the membrane. The problem of peptide binding to membranes, its prediction, measurement, and calculation are addressed. Particular attention is given to understanding the reason for the need for amphipathic structures in the function of membrane-active peptides. Insertion into the membrane is then examined. Hydrophobicity scales are compared, and their influence on calculations is discussed. The relation between translocation and graded or all-or-none peptide-induced flux from or into lipid vesicles is also considered. Finally, the most recent work on translocation is examined, both experimental and from molecular dynamics simulations. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova. © 2014 Elsevier B.V. Source


LaMaskin T.A.,University of North Carolina at Wilmington
GSA Today | Year: 2012

Paleozoic-Mesozoic basins in Cordilleran terranes of western North America contain detrital zircon U-Pb age distributions that vary over 10-100 Ma in a systematic and predictable manner. A minimum of four detrital zircon age distributions, here termed "detrital zircon facies," are present: (1) Paleoproterozoic and Archean facies, chiefly found in Paleozoic and early Mesozoic accretionary complexes, is defined by late Archean-early Proterozoic (ca. 2.7-2.3 Ga) and late Proterozoic ages (ca. 2.0- 1.6 Ga) with variable quantities of Paleozoic and early Mesozoic ages. (2) Mixed Proterozoic and Phanerozoic facies is found in Early-Late Jurassic basins and is defined by grains spanning ca. 2.0 Ga-160 Ma, derived from eastern-southwestern Laurentian transcontinental sources and enriched by western U.S. and eastern Mexican early Mesozoic plate-margin magmatism. (3) Triassic and Jurassic facies, found in Late Jurassic-Early Cretaceous basins, is defined by Late Jurassic ages (peak ca. 155 Ma) with a subordinate proportion of Triassic ages (peak ca. 230 Ma). (4) Jurassic and Early Cretaceous facies is found in late Early-early Late Cretaceous marginal basins and is defined by Jurassic and Early Cretaceous ages (ca. 200-130 and ca. 130-100 Ma). Detrital zircon U-Pb ages from terranes of western North America record stages of basin formation during phases of the supercontinent cycle and reflect second-order variability in the tectonic setting of an active continental plate margin. At this temporal and spatial scale, the integrated evolution of orogenic, erosion, and sedimenttransport systems controls sediment provenance. Source


Pastore R.,University of North Carolina at Wilmington
Computers and Education | Year: 2012

Can increasing the speed of audio narration in multimedia instruction decrease training time and still maintain learning? The purpose of this study was to examine the effects of time-compressed instruction and redundancy on learning and learners' perceptions of cognitive load. 154 university students were placed into conditions that consisted of time-compression (0%, 25%, or 50%) and redundancy (redundant text and narration or narration only). Participants were presented with multimedia instruction on the human heart and its parts then given factual and problem solving knowledge tests, a cognitive load measure, and a review behavior (back and replay buttons) measure. Results of the study indicated that participants who were presented 0% and 25% compression obtained similar scores on both the factual and problem solving measures. Additionally, they indicated similar levels of cognitive load. Participants who were presented redundant instruction were not able to perform as well as participants presented non-redundant instruction. © 2011 Elsevier Ltd. All rights reserved. Source


Pawlik J.R.,University of North Carolina at Wilmington
BioScience | Year: 2011

Sponges are now the dominant habitat-forming animals on Caribbean reefs, where the combined effects of climate change, pollution, and disease have decimated reef-building corals. Natural products chemists have been isolating novel secondary metabolites from Caribbean sponges for many decades, but relevant studies of the ecological functions of these compounds have been more recent. Bioassay-guided surveys have revealed sponge chemical defenses against predators, competitors, and pathogens, but many common sponge species lack chemical defenses and appear to have followed a different evolutionary trajectory, investing instead in greater reproduction or growth. The emerging conceptual model predicts that changes in the abundances of fish-and sponge-eating fishes on Caribbean reefs will have a cascading impact on the sponge community, with indirect effects on the broader community of corals and seaweeds. Caribbean sponges provide an important alternative to terrestrial plant and insect communities for testing basic ecological theories about chemical defenses and resource allocation. © 2011 by American Institute of Biological Sciences. All rights reserved. Source


Almeida P.F.,University of North Carolina at Wilmington
Biophysical Journal | Year: 2011

A theoretical model is proposed to describe the heat capacity function and the phase behavior of binary mixtures of phospholipids and cholesterol. The central idea is that the liquid-ordered state (L o) is a thermodynamic state or an ensemble of conformations of the phospholipid, characterized by enthalpy and entropy functions that are intermediate between those of the solid and the liquid-disordered (L d) states. The values of those thermodynamic functions are such that the L o state is not appreciably populated in the pure phospholipid, at any temperature, because either the solid or the L d state have much lower free energies. Cholesterol stabilizes the L o state by nearest-neighbor interactions, giving rise to the appearance of the L o phase. The model is studied by Monte Carlo simulations on a lattice with nearest-neighbor interactions, which are derived from experiment as much as possible. The calculated heat capacity function closely resembles that obtained by calorimetry. The phase behavior produced by the model is also in agreement with experimental data. The simulations indicate that separation between solid and L o phases occurs below the melting temperature of the phospholipid (T m). Above T m, small L d and L o domains do exist, but there is no phase separation. © 2011 by the Biophysical Society. Source

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