3,036 research outputs found
EP-1949: Developing a Radiotherapy Quality Assurance programme as part of the HIPPO trial (NCT02147028)
High-Resolution Electron Time-of-Flight Apparatus for the Soft-X-Ray Region
A gas-phase time-of-flight (TOF) apparatus, capable of supporting as many as six electron-TOF analyzers viewing the same interaction region, has been developed to measure energy- and angle-resolved electrons with kinetic energies up to 5 keV. Each analyzer includes a newly designed lens system that can retard electrons to about 2% of their initial kinetic energy without significant loss of transmission; the analyzers can thus achieve a resolving power (E/ÎE) greater than 104 over a wide kinetic-energy range. Such high resolving power is comparable to the photon energy resolution of state-of-the-art synchrotronâradiation beamlines in the soft x-ray range, opening the TOF technique to numerous high-resolution applications. In addition, the angular placement of the analyzers, by design, permits detailed studies of nondipolar angular distribution effects in gas-phase photoemission
Personnalité métaphysique et rites traditionnels mortuaires Sud Fore
Ethnographic studies on Melanesian concepts of the human body and religion have expanded our understandings of the concept of personhood. Melanesian ethnographers have used a number of descriptive words to describe the metaphysical components of the person, including: soul, spirit, life force, ghost, and vital and spiritual essence. By investigating the traditional mortuary rites of the South Fore people in Papua New Guinea, which included the practice of endocannibalism, investigators were able to distinguish the 5 souls of the composite metaphysical person and their relationship to the humors of the body. An understanding of the South Fore cosmology and its relationship to its human inhabitants was required to understand these deeply embedded concepts. The South Fore person was found to be composed of 5 souls and bodily humors which together formed a composite individual, yet partible through division. We elucidated the concepts of the 5 souls of the Fore person, which revealed a strong correlation between the landscape with its overlying cosmology and the cultural bodily humors, and demonstrated their relationship to the power of the land.Les Ă©tudes ethnographiques sur les concepts mĂ©lanĂ©siens du corps humain et la religion ont Ă©largi notre comprĂ©hension de la notion de personnalitĂ©. Les ethnographes mĂ©lanĂ©siens ont utilisĂ© un certain nombre de mots descriptifs pour dĂ©crire les composants mĂ©taphysiques de la personne, y compris l'Ăąme, l'esprit, la force de vie, le fantĂŽme et l'essence vitale et spirituelle. En enquĂȘtant sur les rites funĂ©raires traditionnels du peuple du Sud Fore (PNG), avec une pratique de lâendocannibalisme, les enquĂȘteurs ont Ă©tĂ© en mesure de distinguer les cinq Ăąmes de la personne mĂ©taphysique composite et leur relation avec les humeurs du corps. Une bonne comprĂ©hension de la cosmologie du Sud Fore et sa relation avec ses habitants humains ont Ă©tĂ© nĂ©cessaires pour comprendre ces concepts profondĂ©ment ancrĂ©s. La personne du Sud Fore est donc composĂ©e de cinq Ăąmes et humeurs corporelles qui, ensemble, forment un individu composite, encore divisible. Ici est donc Ă©lucidĂ© le concept des cinq Ăąmes de la personne Fore, qui rĂ©vĂšle une forte corrĂ©lation entre le paysage avec sa cosmologie sus-jacente et les humeurs corporelles culturelles, et la preuve de leur relation Ă la puissance de la terre
Trapped lipopolysaccharide and LptD intermediates reveal lipopolysaccharide translocation steps across the Escherichia coli outer membrane
Lipopolysaccharide (LPS) is a main component of the outer membrane of Gram-negative bacteria, which is essential for the vitality of most Gram-negative bacteria and plays a critical role for drug resistance. LptD/E complex forms a N-terminal LPS transport slide, a hydrophobic intramembrane hole and the hydrophilic channel of the barrel, for LPS transport, lipid A insertion and core oligosaccharide and O-antigen polysaccharide translocation, respectively. However, there is no direct evidence to confirm that LptD/E transports LPS from the periplasm to the external leaflet of the outer membrane. By replacing LptD residues with an unnatural amino acid p-benzoyl-L-phenyalanine (pBPA) and UV-photo-cross-linking in E.coli, the translocon and LPS intermediates were obtained at the N-terminal domain, the intramembrane hole, the lumenal gate, the lumen of LptD channel, and the extracellular loop 1 and 4, providing the first direct evidence and âsnapshotsâ to reveal LPS translocation steps across the outer membrane
Spin Star as Switch for Quantum Networks
Quantum state transfer is an important task in quantum information
processing. It is known that one can engineer the couplings of a
one-dimensional spin chain to achieve the goal of perfect state transfer. To
leverage the value of these spin chains, a spin star is potentially useful for
connecting different parts of a quantum network. In this work, we extend the
spin-chain engineering problem to the problems with a topology of a star
network. We show that a permanently coupled spin star can function as a network
switch for transferring quantum states selectively from one node to another by
varying the local potentials only. Together with one-dimensional chains, this
result allows applications of quantum state transfer be applied to more general
quantum networks.Comment: 10 pages, 2 figur
Concerted reductive coupling of an alkyl chloride at Pt(IV)
Oxidation of a doubly cyclometallated platinum(II) complex results in two isomeric platinum(IV) complexes. Whereas the trans isomer is robust, being manipulable in air at room temperature, the cis isomer decomposes at â20 °C and above. Reductive coupling of an alkyl chloride at the cis isomer gives a new species which can be reoxidised. The independence of this coupling on additional halide rules out the reverse of an SN2 reaction, leaving a concerted process as the only sensible reaction pathway
First Results from the High-Brightness X-Ray Spectroscopy Beamline 9.3.1 at ALS
Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1â6 keV photon energy range. This beamline is designed to achieve the goal of high brightness at the sample for use in the xâray atomic and molecular spectroscopy (XAMS) science, surface and interface science, biology and xâray optical development programs at ALS. Xâray absorption and timeâofâflight photoemission measurements in 2â5 keV photon energy range along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented
Electric-octupole and pure-electric-quadrupole effects in soft-x-ray photoemission
Second-order [O(k^2), k=omega/c] nondipole effects in soft-x-ray
photoemission are demonstrated via an experimental and theoretical study of
angular distributions of neon valence photoelectrons in the 100--1200 eV
photon-energy range. A newly derived theoretical expression for nondipolar
angular distributions characterizes the second-order effects using four new
parameters with primary contributions from pure-quadrupole and octupole-dipole
interference terms. Independent-particle calculations of these parameters
account for a significant portion of the existing discrepancy between
experiment and theory for Ne 2p first-order nondipole parameters.Comment: 4 pages, 3 figure
Comparable performance characteristics of plasma thiamine and erythrocyte thiamine diphosphate in response to thiamine fortification in rural cambodian women
Background: Traditionally, vitamin Bâ status is assessed by a functional test measuring erythrocyte transketolase (ETK) activity or direct measurement of erythrocyte thiamine diphosphate (eThDP) concentration. However, such analyses are logistically challenging, and do not allow assessment of vitamin Bâ status in plasma/serum samples stored in biobanks. Using a multiplex assay, we evaluated plasma concentrations of thiamine and thiamine monophosphate (TMP), as alternative, convenient measures of vitamin Bâ status. Methods: We investigated the relationships between the established biomarker eThDP and plasma concentrations of thiamine and TMP, and compared the response of these thiamine forms to thiamine fortification using samples from 196 healthy Cambodian women (aged 18-45 years.). eThDP was measured by high performance liquid chromatography with fluorescence detection (HPLC-FLD) and plasma thiamine and TMP by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: Plasma thiamine and TMP correlated significantly with eThDP at baseline and study-end (p < 0.05). Among the fortification groups, the strongest response was observed for plasma thiamine (increased by 266%), while increases in plasma TMP (60%) and eThDP (53%) were comparable. Conclusions: Plasma thiamine and TMP correlated positively with eThDP, and all thiamine forms responded significantly to thiamine intervention. Measuring plasma concentrations of thiamine forms is advantageous due to convenient sample handling and capacity to develop low volume, high-throughput, multiplex assays.Adrian McCann, Ăivind Midttun, Kyly C. Whitfield, Hou Kroeun, Mam Borath ... Timothy J. Gree
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