6,270 research outputs found
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The free energy of small solute permeation through the E. coli outer membrane has a distinctly asymmetric profile
No full textPermeation of small molecules across cell membranes is aubiquitous process in biology and is dependent on the principles of physicalchemistry at the molecular level. Here we use atomistic molecular dynamicssimulations to calculate the free energy of permeation of a range of smallmolecules through a model of the outer membrane of Escherichia coli, anarchetypical Gram-negative bacterium. The model membrane containslipopolysaccharide (LPS) molecules in the outer leaflet and phospholipids inthe inner leaflet. Our results show that the energetic barriers to permeationthrough the two leaflets of the membrane are distinctly asymmetric; the LPSheadgroups provide a less energetically favorable environment for organiccompounds than do phospholipids. In summary, we provide the firstreported estimates of the relative free energies associated with the differentchemical environments experienced by solutes as they attempt to cross theouter membrane of a Gram-negative bacterium. These results provide keyinsights for the development of novel antibiotics that target these bacteria
Routing Symmetric Demands in Directed Minor-Free Graphs with Constant Congestion
No full textThe problem of routing in graphs using node-disjoint paths has received a lot of attention and a polylogarithmic approximation algorithm with constant congestion is known for undirected graphs [Chuzhoy and Li 2016] and [Chekuri and Ene 2013]. However, the problem is hard to approximate within polynomial factors on directed graphs, for any constant congestion [Chuzhoy, Kim and Li 2016].
Recently, [Chekuri, Ene and Pilipczuk 2016] have obtained a polylogarithmic approximation with constant congestion on directed planar graphs, for the special case of symmetric demands. We extend their result by obtaining a polylogarithmic approximation with constant congestion on arbitrary directed minor-free graphs, for the case of symmetric demands
A multidomain outer membrane protein from Pasteurella multocida: Modelling and simulation studies of PmOmpA
No full textPmOmpA is a two-domain outer membrane protein from Pasteurella multocida. The N-terminal domain of PmOmpA is a homologue of the transmembrane ?-barrel domain of OmpA from Escherichia coli, whilst the C-terminal domain of PmOmpA is a homologue of the extra-membrane Neisseria meningitidis RmpM C-terminal domain. This enables a model of a complete two domain PmOmpA to be constructed and its conformational dynamics explored via MD simulations of the protein embedded within two different phospholipid bilayers (DMPC and DMPE). The conformational stability of the transmembrane ?-barrel is similar to that of a homology model of OprF from Pseudomonas aeruginosa in bilayer simulations. There is a degree of water penetration into the interior of the ?-barrel, suggestive of a possible transmembrane pore. Although the PmOmpA model is stable over 20 ns simulations, retaining its secondary structure and fold integrity throughout, substantial flexibility is observed in a short linker region between the N- and the C-terminal domains. At low ionic strength, the C-terminal domain moves to interact electrostatically with the lipid bilayer headgroups. This study demonstrates that computational approaches may be applied to more complex, multi-domain outer membrane proteins, rather than just to transmembrane ?-barrels, opening the possibility of in silico proteomics approaches to such proteins
Using fossil leaves as evidence for open vegetation
No full textAbstract not availableGregory J. Jordan, Raymond J. Carpenter, Timothy J. Brodrib
Money piece by Timothy P. Agnew, chief executive officer of the Finance Author
No full textMoney piece by Timothy P. Agnew, chief executive officer of the Finance Authority of Maine, about the increased availability of credit for Maine\u27s small businesses
Molecular dynamics simulations reveal the conformational flexibility of Lipid II and its loose association with the defensin plectasin in the Staphylococcus aureus membrane
No full textLipid II is critical for peptidoglycan synthesis, which is the main component of the bacterial cell wall. Lipid II is a relatively conserved and important part of the cell wall biosynthesis pathway and is targeted by antibiotics such as the lantibiotics, which achieve their function by disrupting the biosynthesis of the cell wall. Given the urgent need for development of novel antibiotics to counter the growing threat of bacterial infection resistance, it is imperative that a thorough molecular-level characterization of the molecules targeted by antibiotics be achieved. To this end, we present a molecular dynamics simulation study of the conformational dynamics of Lipid II within a detailed model of the Staphylococcus aureus cell membrane. We show that Lipid II is able to adopt a range of conformations, even within the packed lipidic environment of the membrane. Our simulations also reveal dimerization of Lipid II mediated by cations. In the presence of the defensin peptide plectasin, the conformational lability of Lipid II allows it to form loose complexes with the protein, via a number of different binding modes
OmpA: Gating and dynamics via molecular dynamics simulations
No full textOuter membrane proteins (OMPs) of Gram-negative bacteria have a variety of functions including passive transport, active transport, catalysis, pathogenesis and signal transduction. Whilst the structures of 25 OMPs are currently known, there is relatively little known about their dynamics in different environments. The outer membrane protein, OmpA from Escherichia coli has been studied extensively in different environments both experimentally and computationally, and thus provides an ideal test case for the study of the dynamics and environmental interactions of outer membrane proteins. We review molecular dynamics simulations of OmpA and its homologues in a variety of different environments and discuss possible mechanisms of pore gating. The transmembrane domain of E. coli OmpA shows subtle differences in dynamics and interactions between a detergent micelle and a lipid bilayer environment. Simulations of the crystallographic unit cell reveal a micelle-like network of detergent molecules interacting with the protein monomers. Simulation and modelling studies emphasise the role of an electrostatic-switch mechanism in the pore-gating mechanism. Simulation studies have been extended to comparative models of OmpA homologues from Pseudomonas aeruginosa (OprF) and Pasteurella multocida (PmOmpA), the latter model including the periplasmic C-terminal domain
Timothy Meyer serves as a contributing author for UN report
No full textAssistant Professor Timothy Meyer served as a contributing author for the United Nations Industrial Development Organization\u27s report titled Networks for Prosperity: Connecting Development Knowledge Beyond 2015. The document, which was released during November, analyzes the nexus between the global connectedness of a country and its economic success, sustainability and government effectiveness. Meyer was one of only approximately 20 academic and practical experts from around the world selected to serve as a contributor after a global call for proposals.
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Crimes against morality
No full textThe purpose of this chapter is to discuss the relationship between crime and morality, with a specific focus on crimes against morality. While we argue that all crimes have a general moral basis, condemned as wrong or bad and proscribed by society, there is a specific group of offences in modern democratic nations labelled crimes against morality. Included within this group are offences related to prostitution, pornography and homosexuality. What do these crimes have in common? Most clearly they tend to have a sexual basis and are often argued to do sexual harm, in both a moral and /or psychological sense, as well as physically. Conversely they are often argued to be victimless crimes, especially when the acts occur between consenting adults. Finally they are considered essentially private acts but they often occur, and are regulated, in the public domain. Most importantly, each of these crimes against morality has only relatively recently (ie in the past 150 years) become identified and regulated by the state as a criminal offence
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