7,421 research outputs found
Experience of Using Simulation Technology and Analytics During the Ebola Crisis to Empower Frontline Health Workers and Improve the Integrity of Public Health Systems
Humanitarian Technology: Science, Systems and Global Impact 2016, HumTech2016 keywords: Analytics keywords: Analytics keywords: Analytics keywords: Analytics keywords: Analytics keywords: Analytics keywords: Analytics keywords: Analytics keywords: Analytics keywords: Analytic
Chromophore-labelled, luminescent platinum complexes: syntheses, structures, and spectroscopic properties
Ligands based upon 4-carboxamide-2-phenylquinoline derivatives have been synthesised with solubilising octyl hydrocarbon chains and tethered aromatic chromophores to give naphthyl (HL2), anthracenyl (HL3) and pyrenyl (HL4) ligand variants, together with a non-chromophoric analogue (HL1) for comparison. 1H NMR spectroscopic studies of the ligands showed that two non-interchangeable isomers exist for HL2 and HL4 while only one isomer exists for HL1 and HL3. Supporting DFT calculations on HL4 suggest that the two isomers may be closely isoenergetic with a relatively high barrier to exchange of ca. 100 kJ mol−1. These new ligands were cyclometalated with Pt(II) to give complexes [Pt(L1–4)(acac)] (acac = acetylacetonate). The spectroscopically characterised complexes were studied using multinuclear NMR spectroscopy including 195Pt{1H} NMR studies which revealed δPt ca. −2785 ppm for [Pt(L1–4)(acac)]. X-ray crystallographic studies were undertaken on [Pt(L3)(acac)] and [Pt(L4)(acac)], each showing the weakly distorted square planar geometry at Pt(II); the structure of [Pt(L3)(acac)] showed evidence for intermolecular Pt–Pt interactions. The UV-vis. absorption studies show that the spectral profiles for [Pt(L2–4)(acac)] are a composite of the organic chromophore centred bands and a broad 1MLCT (5d → π*) band (ca. 440 nm) associated with the complex. Luminescence studies showed that complexes [Pt(L2–4)(acac)] are dual emissive with fluorescence characteristic of the tethered fluorophore and long-lived phosphorescence attributed to 3MLCT emission. In the case of the pyrenyl derivative, [Pt(L4)(acac)], the close energetic matching of the 3MLCT and 3LCpyr excited states led to an elongation of the 3MLCT emission lifetime (τ = 42 μs) under degassed solvent conditions, suggestive of energy transfer processes between the two states
Ventilatory and chronotropic incompetence during incremental and constant load exercise in end-stage renal disease:a comparative physiology study
Maximal O(2) uptake is impaired in end-stage renal disease (ESRD), reducing quality of life and longevity. While determinants of maximal exercise intolerance are well defined, little is known of limitation during submaximal constant load exercise. By comparing individuals with ESRD and healthy controls, the aim of this exploratory study was to characterize mechanisms of exercise intolerance in participants with ESRD by assessing cardiopulmonary physiology at rest and during exercise. Resting spirometry and echocardiography were performed in 20 dialysis-dependent participants with ESRD (age: 59 ± 12 yr, 14 men and 6 women) and 20 healthy age- and sex-matched controls. Exercise tolerance was assessed with ventilatory gas exchange and central hemodynamics during a maximal cardiopulmonary exercise test and 30 min of submaximal constant load exercise. Left ventricular mass (292 ± 102 vs. 185 ± 83 g, P = 0.01) and filling pressure (E/e′: 6.48 ± 3.57 vs. 12.09 ± 6.50 m/s, P = 0.02) were higher in participants with ESRD; forced vital capacity (3.44 ± 1 vs. 4.29 ± 0.95 L/min, P = 0.03) and peak O(2) uptake (13.3 ± 2.7 vs. 24.6 ± 7.3 mL·kg(−1)·min(−1), P < 0.001) were lower. During constant load exercise, the relative increase in the arterial-venous O(2) difference (13 ± 18% vs. 74 ± 18%) and heart rate (32 ± 18 vs. 75 ± 29%) were less in participants with ESRD despite exercise being performed at a higher percentage of maximum minute ventilation (48 ± 3% vs. 39 ± 3%) and heart rate (82 ± 2 vs. 64 ± 2%). Ventilatory and chronotropic incompetence contribute to exercise intolerance in individuals with ESRD. Both are potential targets for medical and lifestyle interventions
Microturbulence studies in RFX-mod
Present-days Reversed Field Pinches (RFPs) are characterized by quasi-laminar
magnetic configurations in their core, whose boundaries feature sharp internal
transport barriers, in analogy with tokamaks and stellarators. The abatement of
magnetic chaos leads to the reduction of associated particle and heat transport
along wandering field lines. At the same time, the growth of steep temperature
gradients may trigger drift microinstabilities. In this work we summarize the
work recently done in the RFP RFX-mod in order to assess the existence and the
impact upon transport of such electrostatic and electromagnetic
microinstabilities as Ion Temperature Gradient (ITG), Trapped Electron Modes
(TEM) and microtearing modes.Comment: Work presented at the 2010 Varenna workshop "Theory of Fusion
Plasmas". To appear in Journal of Physics Conference Serie
Rhythmic coma in children.
We describe a syndrome of rhythmic coma in children that consists of an invariant, nonreactive, diffuse cortical activity of a specific frequency, such as alpha, beta, spindle, or theta, recorded from a comatose child. We report 11 cases of children who were found to be in rhythmic coma during their acute illnesses. Their ages ranged from 2 to 15 years, and their diagnoses included encephalitis, head trauma, seizures, near drowning, brain tumors, stroke, and metabolic derangements. The specific frequency of the electroencephalographic pattern, ie, alpha, beta, spindle, or theta, did not influence the outcome. The clinical outcome appeared to depend on the primary disease process rather than the electroencephalographic finding. The prognosis of alpha-frequency rhythmic coma as well as of rhythmic coma in general was better in children than in adults. The pathophysiology in children may be similar, ie, the interruption of reticulothalamocortical pathways by metabolic or structural abnormalities, but the expression of this deafferentation may be more varied in the developing brain. Thus, we propose the term rhythmic coma as a unified concept for alpha, beta, spindle, and theta coma in children
Boson-fermion unification, superstrings, and Bohmian mechanics
Bosonic and fermionic particle currents can be introduced in a more unified
way, with the cost of introducing a preferred spacetime foliation. Such a
unified treatment of bosons and fermions naturally emerges from an analogous
superstring current, showing that the preferred spacetime foliation appears
only at the level of effective field theory, not at the fundamental superstring
level. The existence of the preferred spacetime foliation allows an objective
definition of particles associated with quantum field theory in curved
spacetime. Such an objective definition of particles makes the Bohmian
interpretation of particle quantum mechanics more appealing. The superstring
current allows a consistent Bohmian interpretation of superstrings themselves,
including a Bohmian description of string creation and destruction in terms of
string splitting. The Bohmian equations of motion and the corresponding
probabilistic predictions are fully relativistic covariant and do not depend on
the preferred foliation.Comment: 30 pages, 1 figure, revised, to appear in Found. Phy
Common Era sea-level budgets along the U.S. Atlantic coast
Sea-level budgets account for the contributions of processes driving sea-level change, but are predominantly focused on global-mean sea level and limited to the 20th and 21st centuries. Here we estimate site-specific sea-level budgets along the U.S. Atlantic coast during the Common Era (0-2000 CE) by separating relative sea-level (RSL) records into process-related signals on different spatial scales. Regional-scale, temporally linear processes driven by glacial isostatic adjustment dominate RSL change and exhibit a spatial gradient, with fastest rates of rise in southern New Jersey (1.6 ± 0.02 mm yr-1). Regional and local, temporally non-linear processes, such as ocean/atmosphere dynamics and groundwater withdrawal, contributed between -0.3 and 0.4 mm yr-1 over centennial timescales. The most significant change in the budgets is the increasing influence of the common global signal due to ice melt and thermal expansion since 1800 CE, which became a dominant contributor to RSL with a 20th century rate of 1.3 ± 0.1 mm yr-1
Quantum cosmic models and thermodynamics
The current accelerating phase of the evolution of the universe is considered
by constructing most economical cosmic models that use just general relativity
and some dominating quantum effects associated with the probabilistic
description of quantum physics. Two of such models are explicitly analyzed.
They are based on the existence of a sub-quantum potential and correspond to a
generalization of the spatially flat exponential model of de Sitter space. The
thermodynamics of these two cosmic solutions is discussed, using the second
principle as a guide to choose which among the two is more feasible. The paper
also discusses the relativistic physics on which the models are based, their
holographic description, some implications from the classical energy
conditions, and an interpretation of dark energy in terms of the entangled
energy of the universe.Comment: 15 pages, 1 figure, accepted for publication in Class. Quantum Gra
Two-dimensional turbulence in magnetised plasmas
In an inhomogeneous magnetised plasma the transport of energy and particles
perpendicular to the magnetic field is in general mainly caused by quasi
two-dimensional turbulent fluid mixing. The physics of turbulence and structure
formation is of ubiquitous importance to every magnetically confined laboratory
plasma for experimental or industrial application. Specifically, high
temperature plasmas for fusion energy research are also dominated by the
properties of this turbulent transport. Self-organisation of turbulent vortices
to mesoscopic structures like zonal flows is related to the formation of
transport barriers that can significantly enhance the confinement of a fusion
plasma. This subject of great importance in research is rarely touched on in
introductory plasma physics or continuum dynamics courses. Here a brief
tutorial on 2D fluid and plasma turbulence is presented as an introduction to
the field, appropriate for inclusion in undergraduate and graduate courses.Comment: This is an author-created, un-copyedited version of an article
published in European Journal of Physics. IOP Publishing Ltd is not
responsible for any errors or omissions in this version of the manuscript or
any version derived from it. The definitive publisher authenticated version
is available online at doi: 10.1088/0143-0807/29/5/00
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