13,695 research outputs found
Photoinduced electroreduction of chlorophyllide on alkanethiol-coated mercury
No full textMonolayers of n-alkanethiols of chain length from C-12 to C-18 were self-assembled on a hanging mercury drop electrode, and a film of chlorophyllide (Chlide) was adsorbed on top of them. The reduction photocurrents following illumination of the Chlide film were measured over the potential range in which the Chlide is electroinactive in the dark, and their action spectra were determined. Plotting the derivative of the photocurrents with respect to the applied potential against potential yields bell-shaped curves that can be fitted to a Gaussian. The potential of the Gaussian maximum was used to determine the reorganization energy for the Chlide electroreduction process. An increase in the thiol chain length causes A to decrease regularly and the photocurrent to decay exponentially with the monolayer thickness, with a decay constant beta of about 0. 17 Angstrom(-1)
Incorporation of channel-forming peptides in a Hg-supported lipid bilayer
No full textThe channel-forming peptides gramicidin and alamethicin were incorporated in a mercury-supported lipid bilayer composed of a tethered thiolipid monolayer with a self-assembled dioleoylphosphatidylcholine monolayer on top of it. The thiolipid consists of a hexapeptide chain with a high tendency to form a 310-helical structure, which terminates at the N-terminus end with a sulfydryl group for anchoring to the metal while the C-terminus end is covalently linked to the polar head of dimyristolylphosphatidylethanolamine. The hexapeptide moiety has two triethyleneoxy side chains that impart a satisfactory hydrophilicity and are intended to keep the anchored thiolpeptide chains sufficiently apart, so as to accommodate water molecules and inorganic ions and to create a suitable environment for the incorporation of integral proteins. Changes in the conductance of this biomimetic membrane following the incorporation of gramicidin and alamethicin were detected by impedance spectroscopy. The surface dipole potential of the hexapeptide chain and the transmembrane potential of the lipid bilayer were estimated by using a simple electrostatic model of the mercury|solution interphase
Electrogenic Ion Pumps Investigated on a Solid Supported Membrane: Comparison of Current and Voltage Measurements
No full textCurrent and voltage measurements were performed on Na,K-ATPase and sarcoplasmic reticulum (SR) Ca-ATPase. Measurements of current transients under short-circuit conditions and of voltage transients under open-circuit conditions were carried out by employing a solid supported membrane (SSM). Purified membrane fragments containing Na,K-ATPase or native SR vesicles were adsorbed on a SSM and were activated by performing substrate concentration jumps. Current and voltage transients were recorded in the external circuit, that are related to pump activity, and can be attributed to electrogenic events in the reaction cycles of the two enzymes. While current transients of very small amplitude are difficult to detect, the corresponding voltage transients can be measured with higher accuracy thanks to a much more favourable signal to noise ratio. Therefore, voltage measurements are preferable for the investigation of slow processes generating low current signals, e.g. for the analysis of low turnover transporters
Mr. Melvin J. Collier, RWWL AUC, June 2011
No full textThis video is a conversation with Mr. Melvin J. Collier. Mr. Collier talks about his book, "From Mississippi to Africa: A Journey of Discovery". Daniel Le, AUC Woodruff Library, is the interviewer
Translocation of Platinum Anticancer Drugs by Human Copper ATPases ATP7A and ATP7B
No full textCisplatin, carboplatin, and oxaliplatin are widely used anticancer drugs. Their efficacy is strongly reduced by development of cell resistance. Down-regulation of CTR1 and up-regulation of the Cu-ATPases, ATP7A and ATP7B, have been associated to augmented drug resistance. To gain information on translocation of Pt drugs by human Cu-ATPases, we performed electrical measurements on the COS-1 cell microsomal fraction, enriched with recombinant ATP7A, ATP7B, and selected mutants, and adsorbed on a solid supported membrane. The experimental results indicate that Pt drugs activate Cu-ATPases and undergo ATP-dependent translocation in a fashion similar to that of Cu. We then used NMR spectroscopy and ESI-MS to determine the binding mode of these drugs to the first N-terminal metal-binding domain of ATP7A (Mnk1)
Interview Excerpt of Mr. Donald M. Crawford, Sr.
No full text(1948-2018) Donald Mitchell Crawford, Sr. (“DC”), musician, author, and educator, was born on May 24, 1948, and was a lifelong resident of Birmingham, AL. His father and mother owned and operated “C & S Charter Tours Bus Company,” the first black-owned bus company in the state of Alabama. Crawford was a 1966 graduate of Western Olin High School in Birmingham, AL. Crawford was an outstanding drum major, playing first chair alto saxophone under the tutelage of the late Amos F. Gordon, Sr. After high school, he received a music scholarship to Alabama State University (ASU) where he earned both his Bachelor’s and Master’s Degrees in Music Education and was later inducted into the “School of Music Hall of Fame” at ASU. He was the youngest ever inducted into the Alabama Jazz Hall of Fame. He was a veteran of the U.S. Army and performed with the 291 st and 283rd Army Band in Fort Bennett, GA. DC was Band Director at Jackson Olin High School and taught in the Birmingham School System for over thirty-five years. His love for music and performing lead him after his retirement to serve as Band Director for Miles College.
Crawford is the author of “The Wheels of the Birmingham Civil Rights Movement.” This book chronicles the lives of his late father and mother, Worcy and Christine Pride Crawford, and the role he and the company played in the Birmingham Civil Rights Movement
Interesting anecdotes, memoirs, allegories, essays, and poetical fragments, [electronic resource] : tending to amuse the fancy, and inculcate morality. By Mr. Addison.
No full textMr. Addison is a pseudonym.On p. 1: Anecdote of Cromwell.Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
Interesting anecdotes, memoirs, allegories, essays, and poetical fragments, [electronic resource] : tending to amuse the fancy, and inculcate morality. By Mr. Addison.
No full textMr. Addison is a pseudonym.P. 1 contains an 'Anecdote' beginning "A certain nobleman, .. ".Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
Interesting anecdotes, memoirs, allegories, essays, and poetical fragments, [electronic resource] : tending to amuse the fancy, and inculcate morality. By Mr. Addison.
No full textMr. Addison is a pseudonym.On p. 1: Anecdote of Doctor Young.Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
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