bluuebunny/crossref_metadata_2025 huggingface dataset:
On the molecular structure of HOOO
Authors: McCarthy Michael C. , Lattanzi Valerio , Kokkin Damian , Martinez Oscar , Stanton John F.
Published: January 2012

The molecular structure of trans, planar hydridotrioxygen (HOOO) has been examined by means of isotopic spectroscopy using Fourier transform microwave as well as microwave-millimeter-wave double resonance techniques, and high-level coupled cluster quantum-chemical calculations. Although this weakly bound molecule is readily observed in an electrical discharge of H2O and O2 heavily diluted in an inert buffer gas, we find that HOOO can be produced with somewhat higher abundance using H2 and O2 as precursor gases. Using equal mixtures of normal and 18O2, it has been possible to detect three new isotopic species, H18OOO, HO18O18O, and H18O18O18O. Detection of these species and not others provides compelling evidence that the dominant route to HOOO formation in our discharge is via the reaction OH + O2 → HOOO. By combining derived rotational constants with those for normal HOOO and DOOO, it has been possible to determine a fully experimental (r0) structure for this radical, in which all of the structural parameters (the three bond lengths and two angles) have been varied. This best-fit structure possesses a longer central O–O bond (1.684 Å), in agreement with earlier work, a markedly shorter O–H bond distance (0.913 Å), and a more acute ∠HOO angle (92.4°) when compared to equilibrium (re) structures obtained from quantum-chemical calculations. To better understand the origin of these discrepancies, vibrational corrections have been obtained from coupled-cluster calculations. An empirical equilibrium (\documentclass[12pt]{minimal}\begin{document}$r_e^{\text{emp}}$\end{document}reemp) structure, derived from the experimental rotational constants and theoretical vibrational corrections, gives only somewhat better agreement with the calculated equilibrium structure and large residual inertial defects, suggesting that still higher order vibrational corrections (i.e., γ terms) are needed to properly describe large-amplitude motion in HOOO. Owing to the high abundance of this oxygen-chain radical in our discharge expansion, a very wide spectral survey for other oxygen-bearing species has been undertaken between 6 and 25 GHz. Only about 50% of the observed lines have been assigned to known hydrogen–oxygen molecules or complexes, suggesting that a rich, unexplored oxygen chemistry awaits detection and characterization. Somewhat surprisingly, we find no evidence in our expansion for rotational transitions of cis HOOO or from low-lying vibrationally excited states of trans HOOO under conditions which optimize its ground state lines.
Self-assembled broadband plasmonic nanoparticle arrays for sensing applications
Authors: Verre R. , Fleischer K. , Ualibek O. , Shvets I. V.
Published: January 2012

Highly ordered noble metal nanoparticle (NP) arrays are produced using a glancing angle deposition on stepped substrates. The versatility of the technique is demonstrated by depositing different metals, resulting in shifts of the resonance positions. The behaviour of the NP arrays grown is predicted by a dipolar model, and it is measured using reflectance anisotropy spectroscopy (RAS). Fine tuning of the resonances can be finally realised by selecting the deposition parameters. The combined application of both RAS and deposition at glancing angles provides a unique tool to grow NP arrays with the tunable plasmonic resonances in the entire visible range.
Automatic computer procedure for generating exact and analytical kinetic energy operators based on the polyspherical approach
Authors: Ndong Mamadou , Joubert-Doriol Loïc , Meyer Hans-Dieter , Nauts André , Gatti Fabien , Lauvergnat David
Published: January 2012

We develop a new general code to automatically derive exact analytical kinetic energy operators in terms of polyspherical coordinates. Computer procedures based on symbolic calculations are implemented. Sets of orthogonal or non-orthogonal vectors are used to parametrize the molecular systems in space. For each set of vectors, and whatever the size of the system, the exact analytical kinetic energy operator (including the overall rotation and the Coriolis coupling) can be derived by the program. The correctness of the implementation is tested for different sets of vectors and for several systems of various sizes.
Coupling between internal dynamics and rotational diffusion in the presence of exchange between discrete molecular conformations
Authors: Ryabov Yaroslav , Clore G. Marius , Schwieters Charles D.
Published: January 2012

We present a general formalism for the computation of orientation correlation functions involving a molecular system undergoing rotational diffusion in the presence of transitions between discrete conformational states. In this formalism, there are no proscriptions on the time scales of conformational rearrangement relative to that for rotational diffusion, and the rotational diffusion tensors of the different states can be completely arbitrary. Although closed-form results are limited to the frequency domain, this is generally useful for many spectroscopic observables as the result allows the computation of the spectral density function. We specialize the results for the computation of the frequency-domain correlation function associated with the NMR relaxation.
Fast-electron generation in long-scale-length plasmas
Authors: Yaakobi B. , Chang P.-Y. , Solodov A. , Stoeckl C. , Edgell D. H. , Craxton R. S. , Hu S. X. , Myatt J. F. , Marshall F. J. , Seka W. , Froula D. H.
Published: January 2012

Long-scale-length (∼400-μm) planar CH plasmas have been generated on OMEGA EP with laser intensities of the order of 1014 W/cm2 and ∼1-mm focal spots to quantify the number and temperature of fast electrons caused by the two-plasmon-decay instability. The main diagnostics were the time-integrated Kα line emission and the hard x-ray bremsstrahlung (HXR) from a molybdenum (Mo) substrate. For the intensity range of 1–7 × 1014 W/cm2, the Mo Kα and HXR energies increased by more than three orders of magnitude. The fast-electron temperature in this range (deduced from the x-ray bremsstrahlung emission) rose from ∼20 keV to ∼90 keV. A Monte Carlo code was used to estimate the total energy (or number) of fast electrons based on these two experimental signatures. The resulting energy in fast electrons as a fraction of the laser energy was found to rise in the same intensity range up to ∼1%.
Monolayer dispersion of NiO in NiO/Al2O3 catalysts probed by positronium atom
Authors: Zhang H. J. , Chen Z. Q. , Wang S. J.
Published: January 2012

NiO/Al2O3 catalysts with different NiO loadings were prepared by impregnation method. The monolayer dispersion capacity of NiO is determined to be about 9 wt.% through XRD quantitative phase analysis. Positron lifetime spectra measured for NiO/Al2O3 catalysts comprise two long and two short lifetime components, where the long lifetimes τ3 and τ4 correspond to ortho-positronium (o-Ps) annihilation in microvoids and large pores, respectively. With increasing loading of NiO from 0 to 9 wt.%, τ4 drops drastically from 88 to 38 ns. However, when the NiO loading is higher than 9 wt.%, τ4 shows a slower decrease. Variation of λ4 (1/τ4) as a function of the NiO content can be well fitted by two straight lines with different slopes. The relative intensity of τ4 also shows a fast decrease followed by a slow decrease for the NiO content lower and higher than 9 wt.%, respectively. The coincidence Doppler broadening measurements reveal a continuous increase of S parameter with increasing NiO loading up to 9 wt.% and then a decrease afterwards. This is due to the variation in intensity of the narrow component contributed by the annihilation of para-positronium (p-Ps). Our results show that the annihilation behavior of positronium is very sensitive to the dispersion state of NiO on the surface of γ-Al2O3. When the NiO loading is lower than monolayer dispersion capacity, spin conversion of positronium induced by NiO is the dominant effect, which causes decrease of the longest lifetime and its intensity but increase of the narrow component intensity. After the NiO loading is higher than monolayer dispersion capacity, the spin conversion effect becomes weaker and inhibition of positronium formation by NiO is strengthened, which results in decrease of both the long lifetime intensity and the narrow component intensity. The reaction rate constant is determined to be (1.50 ± 0.04) × 1010 g mol−1s−1 and (3.43 ± 0.20) × 109 g mol−1 s−1 for NiO content below and above monolayer dispersion capacity, respectively.
The effect of salt on ion adsorption on a SiOx alignment film and reduced conductivity of a liquid crystal host
Authors: Huang Yi , Bhowmik Achintya , Bos Philip J.
Published: January 2012

It is shown that the addition of salt to liquid crystal cells, using a SiOx alignment layer, can actually reduce the ion concentration. This seeming contradiction may be explained by the ability of salt to complex with water and to aid the drying of the liquid crystal material. The results show a pathway to purifying liquid crystal devices to the extent needed for low-power low-refresh rate displays for e-book applications.
Fourier, Gauss, Fraunhofer, Porod and the shape from moments problem
Authors: Gallatin Gregg M.
Published: January 2012

We show how the Fourier transform of a shape in any number of dimensions can be simplified using Gauss's law and evaluated explicitly for polygons in two dimensions, polyhedra in three dimensions, etc. We also show how this combination of Fourier and Gauss can be related to numerous classical problems in physics and mathematics. Examples include Fraunhofer diffraction patterns, Porod's law, the shape from moments problem, and Davis's extension of the Motzkin-Schoenberg formula to polygons in the complex plane
Room temperature magnetoelectric properties of type-II InAsSbP quantum dots and nanorings
Authors: Gambaryan K. M. , Aroutiounian V. M. , Harutyunyan V. G. , Marquardt O. , Soukiassian P. G.
Published: January 2012

Quaternary InAsSbP quantum dots (QDs) and quantum rings (QRs) are grown on InAs (100) substrates by liquid phase epitaxy. High resolution scanning electron and atomic force microscopes are used for the characterization. The room temperature optoelectronic and magnetoelectric properties of the InAsSbP type-II QDs and QRs are investigated. For the QD-based structures, specific dips on the capacitance-voltage characteristic are revealed and measured, which are qualitatively explained by the holes thermal and tunnel emissions from the QDs. Specific fractures at room temperature are experimentally found in the magnetic field dependence of an electric sheet resistance for the InAsSbP QRs-based sample.
Ultrabroadband terahertz spectroscopy of chalcogenide glasses
Authors: Zalkovskij Maksim , Zoffmann Bisgaard Christer , Novitsky Andrey , Malureanu Radu , Savastru Dan , Popescu Aurelian , Uhd Jepsen Peter , Lavrinenko Andrei V.
Published: January 2012

Chalcogenide glasses are receiving a lot of attention due to their unique optical properties. In this paper we study the optical properties of As2S3 and GaLaS glasses in a broad terahertz (THz) frequency range (0.2-18 THz). Complex dispersion behavior with drastic changes of refractive index and absorption coefficient is found for both glasses. We observe the breakdown of the universal power-law dependence of the absorption coefficient due to atomic vibrations observed at low THz frequencies in disordered materials, and see the transition to localized vibrational dynamics for the As2S3 compound at higher frequencies. In addition, As2S3 displays two transparency regions, at 7-8 THz and 12.2 THz, of potential interest for future nonlinear applications in the THz range.
Surface transfer doping of diamond with a molecular heterojunction
Authors: Langley D. P. , Smets Y. , Stark C. B. , Edmonds M. T. , Tadich A. , Rietwyk K. J. , Schenk A. , Wanke M. , Wu Q.-H. , Barnard P. J. , Ley L. , Pakes C. I.
Published: January 2012

Surface conductivity and C1s core level measurements were employed to show that surface transfer doping of hydrogen-terminated diamond C(100) can be achieved with a molecular heterojunction formed with C60F48 and an intralayer of zinc-tetraphenylporphyrin. Measurement of the shift in the diamond Fermi energy shows that the zinc-tetraphenylporphyrin (ZnTPP) layer modifies the C60F48–diamond interaction, modulating the extent of charge transfer between the diamond and the fluorofullerene. In contrast to the case of C60F48 acceptors, the presence of a ZnTPP layer prevents the formation of air-induced surface conductivity, showing that the intralayer acts to selectively separate these two doping channels.
Effects of hydrogenation on non-radiative defects in GaNP and GaNAs alloys: An optically detected magnetic resonance study
Authors: Dagnelund D. , Vorona I. P. , Nosenko G. , Wang X. J. , Tu C. W. , Yonezu H. , Polimeni A. , Capizzi M. , Chen W. M. , Buyanova I. A
Published: January 2012

Photoluminescence and optically detected magnetic resonance techniques are utilized to study defect properties of GaNP and GaNAs alloys subjected to post-growth hydrogenation by low-energy sub-threshold ion beam irradiation. It is found that in GaNP H incorporation leads to activation of new defects, which has a Ga interstitial (Gai) atom at its core and may also involve a H atom as a partner. The observed activation critically depends on the presence of N in the alloy, as it does not occur in GaP with a low level of N doping. In sharp contrast, in GaNAs hydrogen is found to efficiently passivate Gai-related defects present in the as-grown material. A possible mechanism responsible for the observed difference in the H behavior in GaNP and GaNAs is discussed.
Directly grown large area single-walled carbon nanotube films with very high sensitivity to normal pressure
Authors: Genest Jonathan , Su Kim Keun , Sauvé Annick , Boissy Patrick , Soucy Gervais , Beauvais Jacques
Published: January 2012

Induction thermal plasma was used to grow a large area, ∼150 mm × 450 mm, and ∼1000 μm thick multi-layered carbon nanotube film. The film is made of a loosely woven structure of single-walled carbon nanotubes uniformly distributed among metallic impurities and carbon black particles. Under cyclic compressive strain, the film acts as a viscoelastic material. A model based on tunneling conduction was used to describe its high piezoresistive sensitivity to normal pressure. The gauge factor obtained for this film was 76.3, more than 20 times higher than the values achieved with a standard buckypaper made from the same nanotube source. This fast and straightforward approach for synthesizing pressure sensitive films is done directly inside the processing system during the growth of the carbon nanotubes. It could provide the means for producing low cost large-scale sensors, such as smart materials for civil and mechanical structures.
Strain induced ionic conductivity enhancement in epitaxial Ce0.9Gd0.1O2−δ thin films
Authors: Mohan Kant K. , Esposito V. , Pryds N.
Published: January 2012

Strained epitaxial Ce0.9Gd0.1O2−δ (CGO) thin films are deposited on MgO(001) substrates with SrTiO3 (STO) buffer layers. The strain in CGO epitaxial thin films is induced and controlled by varying the thickness of STO buffer layers. The induced strain is found to significantly enhance the in-plane ionic conductivity in CGO epitaxial thin films. The ionic conductivity is found to increase with decrease in buffer layer thickness. The tailored ionic conductivity enhancement is explained in terms of close relationships among epitaxy, strain, and ionic conductivity.
Effective homogeneity of the exchange–correlation and non-interacting kinetic energy functionals under density scaling
Authors: Borgoo Alex , Teale Andrew M. , Tozer David J.
Published: January 2012

Correlated electron densities, experimental ionisation potentials, and experimental electron affinities are used to investigate the homogeneity of the exchange–correlation and non-interacting kinetic energy functionals of Kohn–Sham density functional theory under density scaling. Results are presented for atoms and small molecules, paying attention to the influence of the integer discontinuity and the choice of the electron affinity. For the exchange–correlation functional, effective homogeneities are highly system-dependent on either side of the integer discontinuity. By contrast, the average homogeneity—associated with the potential that averages over the discontinuity—is generally close to 4/3 when the discontinuity is computed using positive affinities for systems that do bind an excess electron and negative affinities for those that do not. The proximity to 4/3 becomes increasingly pronounced with increasing atomic number. Evaluating the discontinuity using a zero affinity in systems that do not bind an excess electron instead leads to effective homogeneities on the electron abundant side that are close to 4/3. For the non-interacting kinetic energy functional, the effective homogeneities are less system-dependent and the effect of the integer discontinuity is less pronounced. Average values are uniformly below 5/3. The study provides information that may aid the development of improved exchange–correlation and non-interacting kinetic energy functionals.
State-to-state photodissociation dynamics of triatomic molecules: H2O in the B band
Authors: Jiang Bin , Xie Daiqian , Guo Hua
Published: January 2012

State-to-state photodissociation dynamics of H2O in its B band has been investigated quantum mechanically on a new set of non-adiabatically coupled potential energy surfaces for the lowest two 1A′ states of H2O, which are developed at the internally contracted multi-reference configuration interaction level with the aug-cc-pVQZ basis set. Quantum dynamical calculations carried out using the Chebyshev propagator yield absorption spectra, product state distributions, branching ratios, and differential cross sections, which are in reasonably good agreement with the latest experimental results. Particular focus is placed here on the dependence of various dynamical observables on the photon energy. Detailed analyses of the dynamics have assigned the diffuse structure in absorption spectrum to short-time recurring dynamics near the HOH conical intersection. The non-adiabatic dissociation to the ground state OH product via the HOH conical intersection is facile, direct, fast, and produces rotationally hot OH($\tilde X$X̃) products. On the other hand, the adiabatic channel on the excited state leading to the OH($\tilde A$Ã) product is dominated by long-lived resonances, which depend sensitively on the potential energy surfaces.
Molecular dynamics simulations of shock waves in oriented nitromethane single crystals: Plane-specific effects
Authors: He Lan , Sewell Thomas D. , Thompson Donald L.
Published: January 2012

Molecular dynamics simulations of supported shock waves (shock pressure Ps ∼ 15 GPa) propagating along the [110], [011], [101], and [111] directions in crystalline nitromethane initially at T = 200 K were performed using the nonreactive Sorescu-Rice-Thompson force field [D. C. Sorescu, B. M. Rice, and D. L. Thompson, J. Phys. Chem. B 104, 8406 (2000)10.1021/jp000942q]. These simulations, combined with those from a preceding study of shocks propagating along [100], [010], and [001] directions in nitromethane for similar conditions of temperature and shock pressure [L. He, T. D. Sewell, and D. L. Thompson, J. Chem. Phys. 134, 124506 (2011)10.1063/1.3561397], have been used to study the post-shock relaxation phenomena. Shocks along [010] and [101] lead to a crystal-crystal structure transformation. Shocks propagating along [011], [110], [111], [100], and [001] exhibit plane-specific disordering, which was characterized by calculating as functions of time the 1D mean square displacement (MSD), 2D radial distribution function (RDF), and 2D orientation order parameter P2(θ) in orthogonal planes mutually perpendicular to the shock plane; and by calculating as functions of distance behind the shock front the Cartesian components of intermolecular, intramolecular, and total kinetic energies. The 2D RDF results show that the structural disordering for shocks along [100], [110], and [111] is strongly plane-specific; whereas for shocks along [001] and [011], the loss of crystal structural order is almost equivalent in the orthogonal planes perpendicular to the shock plane. Based on the entire set of simulations, there is a trend for the most extensive disordering to occur in the (010) and ($\overline 1$1¯10) planes, less extensive disordering to occur in the (100) plane, and essentially no disordering to occur in the (001) plane. The 2D P2(θ) and 1D MSD profiles show, respectively, that the orientational and translational disordering is plane-specific, which results in the plane-specific structural disordering observed in the 2D RDF. By contrast, the kinetic energy partitioning and redistribution do not exhibit plane specificity, as shown by the similarity of spatial profiles of the Cartesian components of the intermolecular, intramolecular, and total kinetic energies in orthogonal planes perpendicular to the shock plane.
A tunable Fano resonance in silver nanoshell with a spherically anisotropic core
Authors: Wu DaJian , Jiang ShuMin , Liu XiaoJun
Published: January 2012

The influences of the anisotropic permittivity and permeability in inner core on the Fano resonance have been investigated in Ag nanoshell by means of Mie scattering theory. The decreased inner core radius can enhance the coupling between superradiant and subradiant dipole modes and hence a distinct Fano profile. With increasing the tangential permittivity or permeability of inner core, the Fano resonance shows a redshift and the magnitude of Fano profile increases. The variation of Fano resonance with anisotropic permeability of the core is much weaker than that induced by anisotropic permittivity. We further find that the combined action of the increased tangential permittivity and permeability of inner core can induce a significant enhancement of Fano resonance in Ag nanoshell.
Hybrid modeling and simulation of stochastic effects on progression through the eukaryotic cell cycle
Authors: Liu Zhen , Pu Yang , Li Fei , Shaffer Clifford A. , Hoops Stefan , Tyson John J. , Cao Yang
Published: January 2012

The eukaryotic cell cycle is regulated by a complicated chemical reaction network. Although many deterministic models have been proposed, stochastic models are desired to capture noise in the cell resulting from low numbers of critical species. However, converting a deterministic model into one that accurately captures stochastic effects can result in a complex model that is hard to build and expensive to simulate. In this paper, we first apply a hybrid (mixed deterministic and stochastic) simulation method to such a stochastic model. With proper partitioning of reactions between deterministic and stochastic simulation methods, the hybrid method generates the same primary characteristics and the same level of noise as Gillespie's stochastic simulation algorithm, but with better efficiency. By studying the results generated by various partitionings of reactions, we developed a new strategy for hybrid stochastic modeling of the cell cycle. The new approach is not limited to using mass-action rate laws. Numerical experiments demonstrate that our approach is consistent with characteristics of noisy cell cycle progression, and yields cell cycle statistics in accord with experimental observations.
High-field linear magneto-resistance in topological insulator Bi2Se3 thin films
Authors: He Hongtao , Li Baikui , Liu Hongchao , Guo Xin , Wang Ziyan , Xie Maohai , Wang Jiannong
Published: January 2012

Linear magneto-resistance is observed in high magnetic field in topological insulator Bi2Se3 films. As revealed by tilted magnetic field measurement, this linear magneto-resistance is associated with the gapless topological surface states and of quantum origin. In the ultra-thin limit, the inter-surface tunneling induced surface state gap opening quenches the linear magneto-resistance. Instead, weak negative magneto-resistance is observed in high magnetic fields in ultra-thin films.
The Healthy Lifestyle Scale for University Students: development and psychometric testing
Authors: Dong Wang , Xiao-hui Xing , Xian-bo Wu
Published: January 2012

We report the development and validation of a scale to evaluate the healthy lifestyles of university students. The Delphi technique was used to determine the content validity of the scale with a panel of 33 experts. Psychometric testing was performed and confirmed with 6000 undergraduate students who were randomly selected from 10 universities in China. Three Delphi rounds were required to achieve final consensus for content validity. The split-half correlation coefficient and Cronbach’s α coefficient for the total scale were 0.841 and 0.892, respectively. Construct validity was supported by exploratory factor analysis, which yielded an eight-factor instrument that explained 55.02% of the variance in the 38 items. The proposed Healthy Lifestyle Scale for University Students has good construct validity and reliability and can be used as an evaluation tool for health counselling in university health centres.
Quantitative analysis of the lipidomes of the influenza virus envelope and MDCK cell apical membrane
Authors: Gerl Mathias J. , Sampaio Julio L. , Urban Severino , Kalvodova Lucie , Verbavatz Jean-Marc , Binnington Beth , Lindemann Dirk , Lingwood Clifford A. , Shevchenko Andrej , Schroeder Cornelia , Simons Kai
Published: January 2012

The influenza virus (IFV) acquires its envelope by budding from host cell plasma membranes. Using quantitative shotgun mass spectrometry, we determined the lipidomes of the host Madin–Darby canine kidney cell, its apical membrane, and the IFV budding from it. We found the apical membrane to be enriched in sphingolipids (SPs) and cholesterol, whereas glycerophospholipids were reduced, and storage lipids were depleted compared with the whole-cell membranes. The virus membrane exhibited a further enrichment of SPs and cholesterol compared with the donor membrane at the expense of phosphatidylcholines. Our data are consistent with and extend existing models of membrane raft-based biogenesis of the apical membrane and IFV envelope.
A molecular switch on an arrestin-like protein relays glucose signaling to transporter endocytosis
Authors: Becuwe Michel , Vieira Neide , Lara David , Gomes-Rezende Jéssica , Soares-Cunha Carina , Casal Margarida , Haguenauer-Tsapis Rosine , Vincent Olivier , Paiva Sandra , Léon Sébastien
Published: January 2012

Endocytosis regulates the plasma membrane protein landscape in response to environmental cues. In yeast, the endocytosis of transporters depends on their ubiquitylation by the Nedd4-like ubiquitin ligase Rsp5, but how extracellular signals trigger this ubiquitylation is unknown. Various carbon source transporters are known to be ubiquitylated and endocytosed when glucose-starved cells are exposed to glucose. We show that this required the conserved arrestin-related protein Rod1/Art4, which was activated in response to glucose addition. Indeed, Rod1 was a direct target of the glucose signaling pathway composed of the AMPK homologue Snf1 and the PP1 phosphatase Glc7/Reg1. Glucose promoted Rod1 dephosphorylation and its subsequent release from a phospho-dependent interaction with 14-3-3 proteins. Consequently, this allowed Rod1 ubiquitylation by Rsp5, which was a prerequisite for transporter endocytosis. This paper therefore demonstrates that the arrestin-related protein Rod1 relays glucose signaling to transporter endocytosis and provides the first molecular insights into the nutrient-induced activation of an arrestin-related protein through a switch in post-translational modifications.
Heart failure and socioeconomic status: accumulating evidence of inequality
Authors: Hawkins Nathaniel M. , Jhund Pardeep S. , McMurray John J.V. , Capewell Simon
Published: January 2012

Aims

Socioeconomic status (SES) is a powerful predictor of incident coronary disease and adverse cardiovascular outcomes. Understanding the impact of SES on heart failure (HF) development and subsequent outcomes may help to develop effective and equitable prevention, detection, and treatment strategies

Methods and results

A systematic literature review of electronic databases including PubMed, EMBASE, CINAHL, and the Cochrane Library, restricted to human subjects, was carried out. The principal outcomes were incidence, prevalence, hospitalizations, mortality, and treatment of HF. Socioeconomic measures included education, occupation, employment relations, social class, income, housing characteristics, and composite and area level indicators. Additional studies were identified from bibliographies of relevant articles and reviews. Twenty‐eight studies were identified. Lower SES was associated with increased incidence of HF, either in the community or presenting to hospital. The adjusted risk of developing HF was increased by ∼30–50% in most reports. Readmission rates following hospitalization were likewise greater in more deprived patients. Although fewer studies examined mortality, lower SES was associated with poorer survival. Evidence defining the equity of medical treatment of patients with HF was scarce and conflicting.

Conclusions

Socioeconomic deprivation is a powerful independent predictor of HF development and adverse outcomes. However, the precise mechanisms accounting for this risk remain elusive. Heart failure represents the endpoint of numerous different pathophysiological processes and ‘chains of events’, each modifiable throughout the disease trajectories. The interaction between SES and HF is accordingly complex. Disentangling the many and varied life course processes is challenging. A better understanding of these issues may help attenuate the health inequalities so clearly evident among patients with HF.
Investigations
Authors: Chadwick David , Compston Alastair , Donaghy Michael , Fletcher Nicholas , Grant Robert , Hilton-Jones David , Rossor Martin , Rothwell Peter , Scolding Neil
Published: January 2012

This chapter describes the many methods that can be used to investigate neurological disorders. The application and suitability for specific disorder types are outlined, as are contraindications for use. Methods of imaging the central nervous system include computed tomography (CT) imaging, several magnetic resonance (MR) scanning methods, Single photon emission computed tomography (SPECT) and Positron Emission Tomography (PET). Invasive (angiography) and non-invasive methods of imaging the cerebral circulation are also outlined.

The standard method of recording electrical activity of the brain is the electroencephalogram (EEG), which is heavily used in epilepsy to investigate regions of epileptogenesis.

Other investigations described include evoked potentials, nerve conduction and electromyography studies, the examination of cerebrospinal fluid and the diagnostic use of neurological autoantibodies. Finally, neurogenetics, neuropsychological assessment and the assessment of treatments by randomized trials are discussed.
Toxic and environmental disorders
Authors: Donaghy Michael
Published: January 2012

A huge range of toxins can affect the nervous system, most of which are rarely encountered clinically (Spencer and Schaumburg 2000). This chapter addresses those toxins, medical interventions, and environmental insults with common or noteworthy effects on the nervous system. The peripheral nervous system is particularly vulnerable to toxic effects of drugs, metals, and industrial and agricultural poisons; these manifestations are covered in Chapter 21. Overdosage with an enormous range of drugs and chemicals causes acute poisoning syndromes which affect multiple organ systems, including the nervous system. Such systemic poisonings are not covered below and the reader is referred to comprehensive toxicology reference texts (Dart 2004).
Clinical approach to developmental neurology
Authors: Eyre Janet
Published: January 2012

The objectives and principles of neurological history and examination in children are the same as those in adults. This chapter therefore, will not provide an all-encompassing description of the neurological assessment of children, but highlights where the approach must differ substantially from that used in adults. Further it aims to provide a practical and useful approach to the examination of children, who may be preverbal and certainly will show less stamina for cooperation than adults. Of course as children get older, the examination can become more conventional and systematized. By adolescence the examination can be the same as the adult examination.

The first and overriding factor for success is to be flexible and to make observations when the opportunity arises rather than to wait for abnormalities to arise during the course of a more systematic approach. Nonetheless a systematic approach to recording these results is essential, so as to bring together related observations made disparately in time. The history is of paramount importance in guiding the examination. Since it is unlikely that you will be able to complete a full examination, it is important to prioritize the observations needed in light of a differential diagnosis before you begin examining. Rather than rushing straight into the examination it is rewarding to gain a young child’s confidence by playing briefly with them. Also, instead of insisting on examining the child on a couch, it helps to become adept at examining young children on their parent’s or caretaker’s knee. Finally, no matter how cooperative a child is, potentially disturbing investigations should be left until last, including tendon reflexes or examination of the tongue, fundi, and ears. Otherwise all subsequent cooperation from the child may be lost after these examinations.

The examination room environment is the key to a successful neurological examination and requires careful thought. There should be sufficient space to accommodate families and for the children to play. The room needs to be friendly and conducive to encouraging play. It needs to be equipped with carefully selected toys, pictures, pencils and paper, and books of interest to children over a wide age range. Observation of the child’s play whilst you are taking a history from the parents or caregivers will allow assessment of the child’s motor skills and developmental stage. Their use of play material can yield important clues to the nature of a deficit, by revealing ataxia, weakness, involuntary movements, tics, or spasticity. Play also provides an opportunity to assess the child’s behaviour, for instance their impulsivity, distractibility, and attention span. Interaction of the child with parents or caregivers can be observed also. If the child participates actively in the history taking, their understanding and contribution to the session allows you to make assessments of their language and intellectual skills.
Ocular motor disorders
Authors: Kennard Christopher
Published: January 2012

This chapter discusses motor disorders of the eye. The first part of the chapter describes the proper examination of eye movements to facilitate identification of ocular motor disorder pathology. The effects of nerve palsies on ocular motor function are then described.

Eye movement disorders can also have their cause in the central nervous system; both the brainstem, and cerebellum have been implicated as causal factors in some eye movement disorders. Disorders of the pupil, which affect the pupillary light reflex, can be caused by lesions to central, afferent and efferent pupillary pathways as well as sympathetic pathways lesions.

Finally, this chapter describes diseases of the eye orbits, including dysthyroid eye disease, idiopathic orbital inflammation, orbital tumours, vascular disorders and orbital infections.
Disorders of hearing
Authors: Luxon Linda
Published: January 2012

Hearing loss is the commonest sensory disability worldwide, and the World Health Organisation has estimated that 278 million people suffer a moderate to profound hearing loss in both ears, with 80 per cent of deaf and hearing-impaired people living in low- and middle-income countries (WHO 2006). Tinnitus affects approximately 10 per cent of developed populations (Coles 1984) and of these, 5 per cent find the symptom troublesome and seek help (Davis 1995). Tinnitus and hearing loss are primary symptoms of disordered cochlear function, but may also present as a result of central auditory pathology with normal cochlear function. Pathology affecting the central auditory pathways characteristically presents as difficulty hearing in conditions of poor signal-to-noise ratio, for example, in a classroom in the presence of background noise, listening to transmitted sound, for example on the telephone or on a television, and sound localization. As a consequence of multiple relays and bilateral representation above the level of the cochlear nuclei, central auditory dysfunction does not present with hearing loss. Hearing loss and/or tinnitus, with or without associated vestibular abnormalities, will most commonly be the result of otological pathology. However, importantly for the neurologist cochlear, VIII nerve, or central auditory dysfunction may be part of the clinical presentation of a neurological disorder.
Craniofacial pain
Authors: Scadding John
Published: January 2012

Craniofacial pain, excluding the headache disorders, comprises a heterogeneous group of conditions. Some fall within the sphere of the neurologist, but many call for other specialist skills in diagnosis and management. The site of pain is not always a good guide to either the nature of the pain or the tissue of origin. Patients with craniofacial pain are frequently referred to the neurologist on an assumption that the pain is neuralgic, and for this reason neurologists need to be aware of the many potential causes and be prepared to collaborate closely with other specialists, including the ear, nose, and throat surgeon, ophthalmologist, dental surgeon, oral medicine physician, and psychiatrist. An accurate and detailed history is essential, because in many patients with facial pain, there will be no abnormal physical signs and the diagnosis rests entirely on the history.
Focal peripheral neuropathy
Authors: Donaghy Michael
Published: January 2012

Some causes of focal peripheral nerve damage are self-evident, such as involvement at sites of trauma, tissue necrosis, infiltration by tumour, or damage by radiotherapy. Focal compressive and entrapment neuropathies are particularly valuable to identify in civilian practice, since recovery may follow relief of the compression. Leprosy is a common global cause of focal neuropathy, which involves prominent loss of pain sensation with secondary acromutilation, and requires early antibiotic treatment. Mononeuritis multiplex due to vasculitis requires prompt diagnosis and immunosuppressive treatment to limit the severity and extent of peripheral nerve damage. Various other medical conditions, both inherited and acquired, can present with focal neuropathy rather than polyneuropathy, the most common of which are diabetes mellitus and hereditary liability to pressure palsies. A purely motor focal presentation should raise the question of multifocal motor neuropathy with conduction block, which usually responds well to high-dose intravenous immunoglobulin infusions.
Muscle diseases
Authors: Hilton-Jones David
Published: January 2012

This chapter is concerned with those disorders in which the primary pathological process affects skeletal muscle, for which in everyday clinical practice the term myopathy is convenient shorthand. However, it must be stressed that diseases of the motor nerves and neuromuscular junction can produce an identical clinical picture to several of the myopathies, and this will be emphasized many times throughout the chapter when considering differential diagnosis. Indeed sometimes, despite one’s best efforts, one is left uncertain as to whether the primary disease process is in the nerves or muscles—it may be that in some conditions the disease process directly affects both nerves and muscles. The intimate relationship, both structural and functional, between nerves and the muscles they innervate means that disease of one may have a profound effect on the other—the most striking example is the change that occurs to skeletal muscle fibre-type distribution in denervation.
Head injury
Authors: Whittle Ian
Published: January 2012

Head injury or traumatic brain injury is a ubiquitous phenomenon in all societies and affects up to 2 per cent of the population per year (Bullock et al. 2006). Although the causes of head injury and its distribution within populations vary, it can have devastating consequences both for the patient and family (Tagliaferri et al. 2006). In some countries severe traumatic brain injury is the commonest cause of death in people under 40 years (Lee et al. 2006), and it is estimated that the sequelae of head injury cost societies billions of dollars per year. Understanding of the pathophysiology, diagnosis, and management have all improved dramatically in the last few decades (Steudel et al. 2005). However within western society, perhaps one of the greatest benefits has been the reduction in severe craniocerebral injuries following motor vehicle accidents. This has arisen because of increased safety in car design, seat-belt legislation, the introduction of air-bags, enforcement of speed limits, and the societal conformity to drink-driving legislation. For instance, because of these changes, in the last 15 years the number of severe head injuries managed in the Clinical Neuroscience unit in Edinburgh has decreased by around 66 per cent. Unfortunately in some developing countries one legacy of increased traffic, particularly of motor cycles, is an epidemic of head injuries amongst young adults (Lee et al. 2006). With the number of severe head injuries declining in many countries the challenge will be to provide better care for patients with minor head injury, about 10 times more common than severe injury (Steudel et al. 2005).

Ageing patients who tend to fall over, falls associated with increased alcohol consumption, and domestic or social assaults probably now contribute to the majority of head injuries (Flanagan et al. 2005; Steudel et al. 2005; Tagliaferri et al. 2006). Sporting injuries are fortunately uncommon as a cause of severe craniocerebral injury, although horse riding accidents can sometimes be devastating particularly in teenage girls. In some countries injuries from hand guns and other missiles are common (Aryan et al. 2005), but in European countries many such injuries are self-inflicted. Prompt management of intracranial haematoma, which occurs in 25–45 per cent of severe head injuries, 3–12 per cent of moderate injuries, and 0.2 per cent of minor injuries, and the rehabilitation of patients with head injury are now important areas in clinical neuroscience (Flanagan et al. 2005; Bullock et al. 2006b, c).
Raised intracranial pressure, cerebral oedema, and hydrocephalus
Authors: Whittle Ian
Published: January 2012

The brain is protected by the cranial skeleton. Within the intracranial compartment are also cerebrospinal fluid, CSF, and the blood contained within the brain vessels. These intracranial components are in dynamic equilibrium due to the pulsations of the heart and the respiratory regulated return of venous blood from the brain. Normally the mean arterial blood pressure, systemic venous pressure, and brain volume are regulated to maintain physiological values for intracranial pressure, ICP. There are a range of very common disorders such as stroke, and much less common, such as idiopathic intracranial hypertension, that are associated with major disturbances of intracranial pressure dynamics. In some of these the contribution to pathophysiology is relatively minor whereas in others it may be substantial and be a major contributory factor to morbidity or even death.

Intracranial pressure can be disordered because of brain oedema, disturbances in CSF flow, mass lesions, and vascular engorgement of the brain. Each of these may have variable causes and there may be interactions between mechanisms. In this chapter the normal regulation of intracranial pressure is outlined and some common disease states in clinical neurological practice that are characterized by either primary or secondary problems in intracranial pressure dynamics described.
Cauda equina lesions, radiculopathies, and sphincter disorders
Authors: Bates David
Published: January 2012

Pathological processes involving the spinal roots and cauda equina present with symptoms of lower motor neurone and first order sensory neurone damage. Pain is a common, though not inevitable, symptom. Pathological processes may be acute, as with a prolapsed intervertebral disc or chronic and extend over many years, as with spondylotic bony changes or structural diseases such as spondylolisthesis. The cauda equina carries innervation to the bladder, rectum, corpus cavernosum, and seminal vesicles and damage commonly presents with sphincter disturbance and impotence. In general the nerve roots throughout the spine and cauda equina are more resistant to injury and pathological processes than the spinal cord; rapid diagnosis and surgical intervention where indicated, may improve outcome considerably.
Seizures and related disorders in children
Authors: Cross Helen
Published: January 2012

Epilepsy is most prevalent at each end of the age spectrum—the very young and the very old. Up to 1 per cent of the childhood population will have active epilepsy at any time. Of these 60–70 per cent will be controlled on medication or enter into spontaneous remission, however the remainder will continue to have seizures despite the range of treatment available. There will be associated comorbidity of learning and behaviour difficulties in a significant proportion, and these may take precedence in management over the seizures themselves. Careful evaluation of each individual child with regard to the possible diagnosis and associated comorbidities is required in all children presenting with recurrent paroxysmal episodes in order to optimize management.
Seizures, epilepsy, and other episodic disorders in adults
Authors: Chadwick David
Published: January 2012

Epilepsy, or more correctly a seizure, is most easily defined in physiological terms, being ‘the name for occasional sudden, excessive, rapid, and local discharges of grey matter’ (Jackson 1873). It is more difficult to offer a comprehensive clinical definition of epileptic seizures and epilepsy because of the varied clinical manifestations produced by cerebral neuronal discharge. However, an epileptic seizure can be defined as an intermittent and stereotyped disturbance of consciousness, behaviour, emotion, motor function, or sensation that on clinical grounds is believed to result from cortical neuronal discharge. Epilepsy can then be defined as a condition in which seizures recur, usually spontaneously. The differential diagnosis of epilepsy is large because of the enormous range of symptoms that can occur during seizures. Inevitably, the differential diagnosis for tonic-clonic seizures is very different from that for simple partial seizures with autonomic symptoms. The most common clinical problem is the differential diagnosis from other causes of transient loss of consciousness associated with collapse, the commonest cause of which is syncope.