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Full-Text Articles in Social and Behavioral Sciences
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Danielle Skropeta
The analysis of complex volatile mixtures by gas chromatography-mass spectrometry (GC-MS) is a time-consuming process. It involves separation and identification of the components based on their retention times and fragmentation patterns, followed by determination of their relative percentages from integration of their peak areas. Herein we show that multivariate statistical analysis of the relative abundances of the m/z values obtained from the average mass scans (AMS) of the complex mixture is a faster and potentially more reliable method of assessing these mixtures. To achieve this, 15 model complex mixtures, were prepared comprising varying amounts of 10 different constituents. The AMS …
Differentiation Of Complex Lipid Isomers By Radical-Directed Dissociation Mass Spectrometry, Huong Pham, Tony Ly, Adam Trevitt, Todd Mitchell, Stephen Blanksby
Differentiation Of Complex Lipid Isomers By Radical-Directed Dissociation Mass Spectrometry, Huong Pham, Tony Ly, Adam Trevitt, Todd Mitchell, Stephen Blanksby
Adam Trevitt
Contemporary lipidomics protocols are dependent on conventional tandem mass spectrometry for lipid identification. This approach is extremely powerful for determining lipid class and identifying the number of carbons and the degree of unsaturation of any acyl-chain substituents. Such analyses are however, blind to isomeric variants arising from different carbon−carbon bonding motifs within these chains including double bond position, chain branching, and cyclic structures. This limitation arises from the fact that conventional, low energy collision-induced dissociation of even-electron lipid ions does not give rise to product ions from intrachain fragmentation of the fatty acyl moieties. To overcome this limitation, we have …
Site-Specific Covalent Attachment Of Dna To Proteins Using A Photoactivatable Tus-Ter Complex, Dahdah B. Dahdah, Isabelle Morin, Morgane Moreau, Nicholas E. Dixon, Patrick M. Schaeffer
Site-Specific Covalent Attachment Of Dna To Proteins Using A Photoactivatable Tus-Ter Complex, Dahdah B. Dahdah, Isabelle Morin, Morgane Moreau, Nicholas E. Dixon, Patrick M. Schaeffer
Professor Nick E Dixon
Investigations into the photocrosslinking kinetics of the protein Tus with various bromodeoxyuridine-substituted Ter DNA variants highlight the potential use of this complex as a photoactivatable connector between proteins of interest and specific DNA sequences.
Structure Of The Theta Subunit Of Escherichia Coli Dna Polymerase Iii In Complex With The Epsilon Subunit, Max A Keniry, Ah-Young Park, Elisabeth A. Owen, Samir M. Hamdan, Guido Pintacuda, Gottfried Otting, Nicholas E. Dixon
Structure Of The Theta Subunit Of Escherichia Coli Dna Polymerase Iii In Complex With The Epsilon Subunit, Max A Keniry, Ah-Young Park, Elisabeth A. Owen, Samir M. Hamdan, Guido Pintacuda, Gottfried Otting, Nicholas E. Dixon
Professor Nick E Dixon
The catalytic core of Escherichia coli DNA polymerase III contains three tightly associated subunits, the α, ε, and θ subunits. The θ subunit is the smallest and least understood subunit. The three-dimensional structure of θ in a complex with the unlabeled N-terminal domain of the ε subunit, ε186, was determined by multidimensional nuclear magnetic resonance spectroscopy. The structure was refined using pseudocontact shifts that resulted from inserting a lanthanide ion (Dy3+, Er3+, or Ho3+) at the active site of ε186. The structure determination revealed a three-helix bundle fold that is similar to the solution structures of θ in a methanol-water …
Replication Termination In Escherichia Coli: Structure And Anti-Helicase Activity Of The Tus-Ter Complex, Cameron Neylon, Andrew V. Kralicek, Thomas M. Hill, Nicholas E. Dixon
Replication Termination In Escherichia Coli: Structure And Anti-Helicase Activity Of The Tus-Ter Complex, Cameron Neylon, Andrew V. Kralicek, Thomas M. Hill, Nicholas E. Dixon
Professor Nick E Dixon
The arrest of DNA replication in Escherichia coli is triggered by the encounter of a replisome with a Tus protein-Ter DNA complex. A replication fork can pass through a Tus-Ter complex when traveling in one direction but not the other, and the chromosomal Ter sites are oriented so replication forks can enter, but not exit, the terminus region. The Tus-Ter complex acts by blocking the action of the replicative DnaB helicase, but details of the mechanism are uncertain. One proposed mechanism involves a specific interaction between Tus-Ter and the helicase that prevents further DNA unwinding, while another is that the …
Proofreading Exonuclease On A Tether: The Complex Between The E. Coli Dna Polymerase Iii Subunits Α, Ε, Θ And Β Reveals A Highly Flexible Arrangement Of The Proofreading Domain, Kiyoshi Ozawa, Nicholas P. Horan, Andrew Robinson, Hiromasa Yagi, Flynn R. Hill, Slobodan Jergic, Zhi-Qiang Xu, Karin V. Loscha, Nan Li, Moeava Tehei, Aaron J. Oakley, Gottfried Otting, Thomas Huber, Nicholas E. Dixon
Proofreading Exonuclease On A Tether: The Complex Between The E. Coli Dna Polymerase Iii Subunits Α, Ε, Θ And Β Reveals A Highly Flexible Arrangement Of The Proofreading Domain, Kiyoshi Ozawa, Nicholas P. Horan, Andrew Robinson, Hiromasa Yagi, Flynn R. Hill, Slobodan Jergic, Zhi-Qiang Xu, Karin V. Loscha, Nan Li, Moeava Tehei, Aaron J. Oakley, Gottfried Otting, Thomas Huber, Nicholas E. Dixon
Professor Nick E Dixon
A complex of the three (αεθ) core subunits and the β2 sliding clamp is responsible for DNA synthesis by Pol III, the Escherichia coli chromosomal DNA replicase. The 1.7 Å crystal structure of a complex between the PHP domain of α (polymerase) and the C-terminal segment of ε (proofreading exonuclease) subunits shows that ε is attached to α at a site far from the polymerase active site. Both α and ε contain clamp-binding motifs (CBMs) that interact simultaneously with β2 in the polymerization mode of DNA replication by Pol III. Strengthening of both CBMs enables isolation of stable αεθ:β2 complexes. …
Rotationally Resolved Infrared Spectrum Of The Li+_D2 Cation Complex, C D. Thompson, C Emmeluth, B L. J Poad, G H. Weddle, E J. Bieske
Rotationally Resolved Infrared Spectrum Of The Li+_D2 Cation Complex, C D. Thompson, C Emmeluth, B L. J Poad, G H. Weddle, E J. Bieske
Berwyck L. J. Poad
The infrared spectrum of mass selected Li +-D 2 cations is recorded in the D-D stretch region (2860-2950 cm -1) in a tandem mass spectrometer by monitoring Li + photofragments. The D-D stretch vibration of Li +-D 2 is shifted by -79 cm -1 from that of the free D 2 molecule indicating that the vibrational excitation of the D 2 subunit strengthens the effective Li +-D 2 intermolecular interaction. Around 100 rovibrational transitions, belonging to parallel K a=0-0, 1-1, and 2-2 subbands, are fitted to a Watson A-reduced Hamiltonian to yield effective molecular parameters. The infrared spectrum shows that …
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Berwyck L. J. Poad
The infrared spectrum of mass-selected Na+-D2 complexes is recorded in the D-D stretch vibration region (2915-2972 cm−1) by detecting Na+ photofragments resulting from photo-excitation of the complexes. Analysis of the rotationally resolved spectrum confirms a T-shaped equilibrium geometry for the complex and a vibrationally averaged intermolecular bond length of 2.461 Å. The D-D stretch band centre occurs at 2944.04 cm−1, representing a −49.6 cm−1 shift from the Q1(0) transition of the free D2 molecule. Variational rovibrational energy level calculations are performed for Na+-D2 utilising an ab initio potential energy surface developed previously for investigating the Na+-H2 complex [B. L. J. …
Spectroscopic Study Of The Benchmark Mn+-H2 Complex, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Spectroscopic Study Of The Benchmark Mn+-H2 Complex, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Berwyck L. J. Poad
We have recorded the rotationally resolved infrared spectrum of the weakly bound Mn+-H2 complex in the H-H stretch region (4022-4078 cm(-1)) by monitoring Mn+ photodissociation products. The band center of Mn+-H2, the H-H stretch transition, is shifted by -111.8 cm(-1) from the transition of the free H2 molecule. The spectroscopic data suggest that the Mn+-H2 complex consists of a slightly perturbed H2 molecule attached to the Mn+ ion in a T-shaped configuration with a vibrationally averaged intermolecular separation of 2.73 A. Together with the measured Mn+...H2 binding energy of 7.9 kJ/mol (Weis, P.; et al. J. Phys. Chem. A 1997, …
Mid-Holocene Age Obtained For Nested Diamond Pattern Petroglyph In The Billasurgam Cave Complex, Kurnool District, Southern India, Paul S.C Tacon, Nicole Boivin, Michael Petraglia, James Blinkhorn, Allan Chivas, Richard G. Roberts, David Fink, Thomas Higham, Peter Ditchfield, Ravi Korisettar, Jian-Xin Zhao
Mid-Holocene Age Obtained For Nested Diamond Pattern Petroglyph In The Billasurgam Cave Complex, Kurnool District, Southern India, Paul S.C Tacon, Nicole Boivin, Michael Petraglia, James Blinkhorn, Allan Chivas, Richard G. Roberts, David Fink, Thomas Higham, Peter Ditchfield, Ravi Korisettar, Jian-Xin Zhao
Richard G Roberts
India has one of the world's largest and most significant bodies of rock paintings and engravings, yet not a single rock art site or image has been directly and accurately dated using radiometric techniques. Here we report on results from the Billasurgam Cave complex near Kurnool in southern India. Although this cave complex has been investigated archaeologically since the late 1800s, it was not until 2008 that a large petroglyph, consisting of the remains of three nested diamond designs on a stalactite, was noted. In order to determine if this petroglyph had been made recently, flowstone was sampled from on …
Shell Artefacts And Shell-Working Within The Lapita Cultural Complex, Katherine A. Szabo
Shell Artefacts And Shell-Working Within The Lapita Cultural Complex, Katherine A. Szabo
Katherine A Szabo
Despite a consistent presence in the archaeological record of the Lapita cultural complex, and their omnipresence in the associated literature, the nature and range of shell artefacts recovered from Lapita sites has only been partially summarized at best. Considering the categories of raw material choice, working techniques, formal artefact types and curation, this article summarizes our current knowledge and points to areas for further research.