bluuebunny/crossref_metadata_2025 huggingface dataset:
Collision limited reaction rates for arbitrarily shaped particles across the entire diffusive Knudsen number range
Authors: Gopalakrishnan Ranganathan , Thajudeen Thaseem , Hogan Christopher J.
Published: August 2011

Aerosol particle reactions with vapor molecules and molecular clusters are often collision rate limited, hence determination of particle-vapor molecule and particle-molecular cluster collision rates are of fundamental importance. These collisions typically occur in the mass transfer transition regime, wherein the collision kernel (collision rate coefficient) is dependent upon the diffusive Knudsen number, KnD. While this alone prohibits analytical determination of the collision kernel, aerosol particle- vapor molecule collisions are further complicated when particles are non-spherical, as is often the case for particles formed in high temperature processes (combustion). Recently, through a combination of mean first passage time simulations and dimensional analysis, it was shown that the collision kernel for spherical particles and vapor molecules could be expressed as a dimensionless number, H, which is solely a function of KnD. In this work, it is shown through similar mean first passage times and redefinitions of H and KnD that the H(KnD) relationship found for spherical particles applies for particles of arbitrary shape, including commonly encountered agglomerate particles. Specifically, it is shown that to appropriately define H and KnD, two geometric descriptors for a particle are necessary: its Smoluchowski radius, which defines the collision kernel in the continuum regime (KnD→0) and its orientationally averaged projected area, which defines the collision kernel in the free molecular regime (KnD→∞). With these two parameters, as well as the properties of the colliding vapor molecule (mass and diffusion coefficient), the particle-vapor molecule collision kernel in the continuum, transition, and free molecular regimes can be simply calculated using the H(KnD) relationship.
Enhanced sensitivity of magnetoelectric sensors by tuning the resonant frequency
Authors: Petrie Jonathan R. , Fine Jonathan , Mandal Sanjay , Sreenivasulu Gollapudi , Srinivasan Gopalan , Edelstein Alan S.
Published: August 2011

The sensitivity of magnetoelectric (ME) sensors is more than an order of magnitude higher at their mechanical resonant frequency fr. By applying a restoring torque to an asymmetric ME sensor, we have increased its effective stiffness and, thus, fr by 20% while maintaining the enhanced sensitivity at resonance. The torque was dependent on both the tensile force from a suspended weight and the length of the wire attaching it. This provides two alternative routes for tuning fr to optimize performance. We have detected fields below 10 pT at both the shifted and unshifted fr of 132.2 Hz.
Strain relaxation in GaN/AlxGa1-xN superlattices grown by plasma-assisted molecular-beam epitaxy
Authors: Kotsar Y. , Doisneau B. , Bellet-Amalric E. , Das A. , Sarigiannidou E. , Monroy E.
Published: August 2011

We have investigated the misfit relaxation process in GaN/AlxGa1−xN (x = 0.1, 0.3, 0.44) superlattices (SL) deposited by plasma-assisted molecular beam epitaxy. The SLs under consideration were designed to achieve intersubband absorption in the mid-infrared spectral range. We have considered the case of growth on GaN (tensile stress) and on AlGaN (compressive stress) buffer layers, both deposited on GaN-on-sapphire templates. Using GaN buffer layers, the SL remains almost pseudomorphic for x = 0.1, 0.3, with edge-type threading dislocation densities below 9 × 108 cm−2 to 2 × 109 cm−2. Increasing the Al mole fraction to 0.44, we observe an enhancement of misfit relaxation resulting in dislocation densities above 1010 cm−2. In the case of growth on AlGaN, strain relaxation is systematically stronger, with the corresponding increase in the dislocation density. In addition to the average relaxation trend of the SL, in situ measurements indicate a periodic fluctuation of the in-plane lattice parameter, which is explained by the different elastic response of the GaN and AlGaN surfaces to the Ga excess at the growth front. The results are compared with GaN/AlN SLs designed for near-infrared intersubband absorption.
Highly reproducible memory effect of organic multilevel resistive-switch device utilizing graphene oxide sheets/polyimide hybrid nanocomposite
Authors: Wu Chaoxing , Li Fushan , Zhang Yongai , Guo Tailiang , Chen Ting
Published: August 2011

The functionalization of graphene oxide (GO) sheets with polyimide (PI) enables the layer-by-layer fabrication of a GO-PI hybrid resistive-switch device and leads to high reproducibility of the memory effect. The current-voltage curves for the as-fabricated device exhibit multilevel resistive-switch properties under various reset voltages. The capacitance-voltage characteristics for a capacitor based on GO-PI nanocomposite indicate that the electrical switching may originate from the charge trapping in GO sheets. The high device-to-device uniformity and unique memory properties of the device make it an attractive candidate for applications in next-generation high-density nonvolatile flash memories.
High performance silicon-on-insulator based ion-sensitive field-effect transistor using high-k stacked oxide sensing membrane
Authors: Jang Hyun-June , Cho Won-Ju
Published: August 2011

High performance ion-sensitive field-effect transistors (ISFETs) were realized using silicon-on insulator substrate (SOI) and engineered sensing membrane. The engineered sensing membrane for the gate oxide was proposed to improve the chemical stability and obtain the enhanced output signal by stacking SiO2/HfO2/Al2O3 (OHA) layers. The SOI-metal–oxide–semiconductor field effect transistor (MOSFET) with the OHA gate oxide showed a high on/off current ratio of 1.8 × 1010 and a low subthreshold swing of 65 mV/dec. The SOI based ISFET with the OHA membrane exhibited a low drift rate of 0.23 mV/h, a low hysteresis width of 1.85 mV, and a high pH sensitivity level of 57.1 mV/pH.
Morphology-induced plasmonic resonances in silver-aluminum alloy thin films
Authors: Auer Sabine , Wan Wenjie , Huang Xu , Ramirez Ainissa G. , Cao Hui
Published: August 2011

We have investigated the optical properties of sputter-deposited silver-aluminum alloy thin films on silicon substrates at room temperature. In addition to the primary feature that corresponds to the bulk plasma resonance, a secondary dip appears in the optical reflectance spectra, which shifts and diminishes with thermal annealing. Careful structural characterization of both the as-deposited and annealed films suggests that the resonant feature originates from the surface plasmon resonances, which are localized in the dielectric gap between grains. This result indicates that the morphology of metal alloys could have a significant effect on their optical properties.
Effects of ferroelectric dead layer on the electron transport in ferroelectric tunneling junctions
Authors: Sun Ping , Wu Yin-Zhong , Cai Tian-Yi , Ju Sheng
Published: August 2011

Ferroelectric dead layer is intrinsic and inevitable at the metal-ferroelectrics interface. In general, it is detrimental to the application of nanoscale devices; however, in ferroelectric tunneling junctions with ferroelectric dead layer, an enhanced tunneling electroresistance (TER) can be achieved when the nonswitchable interface polarization at both metal-ferroelectrics interfaces points to the ferroelectric center. The larger the interface polarization, the stronger the TER. In addition, low dielectric constant of dead layer will favor such enhancement. Our results provide an alternative route for achieving larger TER in ferroelectric junctions.
d
ferromagnetism in undoped sphalerite ZnS nanoparticles
Authors: Gao Daqiang , Yang Guijin , Zhang Jing , Zhu Zhonghua , Si Mingsu , Xue Desheng
Published: August 2011

We report the sulfur vacancies-related d0 ferromagnetism in undoped sphalerite ZnS nanoparticles. Systematically tune of sulfur deficiency in ZnS nanoparticles was done by selecting different synthesized temperatures and varying the ratio of hydrogen and argon in post-annealing processes. Our study suggests that such sulfur vacancies can induce the room temperature ferromagnetism. Importantly, the ferromagnetism can be modulated by changing the concentration of sulfur vacancies in the samples. This finding should be the focus of future electronic and spintronic devices.
Patterning of silver nanoparticles on visible light-sensitive Mn-doped lithium niobate photogalvanic crystals
Authors: Liu Xiaoyan , Hatano Hideki , Takekawa Shunji , Ohuchi Fumio , Kitamura Kenji
Published: August 2011

Visible light-induced polarization-dependent photochemical deposition of silver nanoparticles (AgNPs) has been demonstrated using Mn-doped congruent LiNbO3 (CLN) single crystals. Mn-doped CLN has a strong absorption over a wide region of the visible spectrum that allowed effective visible light irradiation for photochemical deposition. The AgNPs deposition on Mn-doped CLN was compared with that on non-doped congruent LiNbO3, and together these further confirmed that the photochemical deposition on LiNbO3 is caused by the strong photogalvanic effect.
A new upper limit on the electron’s electric dipole moment
Authors: Schwarzschild Bertram M.
Published: August 2011

Most proposed extensions of particle theory’s standard model predict that the electron has an electric dipole moment just big enough to measure with new molecular-beam techniques.
Focus on analytical equipment and diagnostics
Authors: Mandelis Andreas
Published: August 2011

The descriptions of the new products listed in this section are based on information supplied to us by the manufacturers. PHYSICS TODAY can assume no responsibility for their accuracy. For more information about a particular product, vis the website at the end of the product description.
Plasma potential and turbulence dynamics in toroidal devices (survey of T-10 and TJ-II experiments)
Authors: Melnikov A.V. , Hidalgo C. , Eliseev L.G. , Ascasibar E. , Chmyga A.A. , Dyabilin K.S. , Krasilnikov I.A. , Krupin V.A. , Krupnik L.I. , Khrebtov S.M. , Komarov A.D. , Kozachek A.S. , López-Bruna D. , Lysenko S.E. , Mavrin V.A. , de Pablos J.L. , Pastor I. , Perfilov S.V. , Pedrosa M.A. , Shurygin R.V. , Vershkov V.A.
Published: August 2011

A direct comparison of the electric potential and its fluctuations in the T-10 tokamak and the TJ-II stellarator is presented for similar plasma conditions in the two machines, using the heavy ion beam probe diagnostic. We observed the following similarities: (i) plasma potentials of several hundred volts, resulting in a radial electric field E

r
of several tens of V cm−1; (ii) a negative sign for the plasma potential at central line-averaged electron densities larger than
, with comparable values in both machines, even when using different heating methods; (iii) with increasing electron density n
e or energy confinement time τ
E
, the potential evolves in the negative direction; (iv) with electron cyclotron resonance heating and associated increase in the electron temperature T
e, τ
E
degrades and the plasma potential evolves in the positive direction. We generally find that the more negative potential and E

r
values correspond to higher values of τ
E
. Modelling indicates that basic neoclassical mechanisms contribute significantly to the formation of the electric potential in the core. Broadband turbulence is suppressed at spontaneous and biased transitions to improved confinement regimes and is always accompanied by characteristic changes in plasma potential profiles. Various types of quasi-coherent potential oscillations are observed, among them geodesic acoustic modes in T-10 and Alfvén eigenmodes in TJ-II.
Summary of the 19th International Atomic Energy Agency Technical Meeting on ‘Research Using Small Fusion Devices’
Authors: Van Oost G. , Mank G.
Published: August 2011

This paper presents a summary of recent results reported on several topics on magnetic confinement, dense magnetized plasmas, innovative fusion technology and applications, diagnostic systems and control and data acquisition systems. The main topics covered on the magnetic confinement devices, diagnostics and data acquisition concern the tokamak KTM (Kazakhstan Tokamak for Material testing) for materials research and testing, and IAEA Joint Experiments on small tokamaks. For the dense magnetized plasmas results on development and commissioning of plasma focus devices were reported. The plasmatron VISION I for innovative plasma–wall interaction studies, a lithium divertor for KTM and compact fusion reactors as neutron sources were presented.
Coupling modes of gold trimer superstructures
Authors: Funston Alison M. , Davis Timothy J. , Novo Carolina , Mulvaney Paul
Published: August 2011

An experimental and theoretical examination of the coupling modes within superstructures of gold nanorod trimers is presented. The experimentally determined spectrum of the nanorod trimers is reported and the modes are elucidated using an electrostatic eigenmode method based on the coupling of evanescent electric fields. The theory is able to reproduce the experimental spectrum well, and the nature of the modes and interactions are discussed.
Gain and plasmon dynamics in active negative-index metamaterials
Authors: Wuestner Sebastian , Pusch Andreas , Tsakmakidis Kosmas L. , Hamm Joachim M. , Hess Ortwin
Published: August 2011

Photonic metamaterials allow for a range of exciting applications unattainable with ordinary dielectrics. However, the metallic nature of their meta-atoms may result in increased optical losses. Gain-enhanced metamaterials are a potential solution to this problem, but the conception of realistic, three-dimensional designs is a challenging task. Starting from fundamental electrodynamic and quantum mechanical equations, we establish and deploy a rigorous theoretical model for the spatial and temporal interaction of lightwaves with free and bound electrons inside and around metallic (nano-) structures and gain media. The derived numerical framework allows us to self-consistently study the dynamics and impact of the coherent plasmon–gain interaction, nonlinear saturation, field enhancement, radiative damping and spatial dispersion. Using numerical pump–probe experiments on a double-fishnet metamaterial structure with dye molecule inclusions, we investigate the build-up of the inversion profile and the formation of the plasmonic modes in a low-
Q
cavity. We find that full loss compensation occurs in a regime where the real part of the effective refractive index of the metamaterial becomes more negative compared to the passive case. Our results provide a deep insight into how internal processes affect the overall optical properties of active photonic metamaterials fostering new approaches to the design of practical, loss-compensated plasmonic nanostructures.
Molecular plasmonics: light meets molecules at the nanoscale
Authors: Csaki Andrea , Schneider Thomas , Wirth Janina , Jahr Norbert , Steinbrück Andrea , Stranik Ondrej , Garwe Frank , Müller Robert , Fritzsche Wolfgang
Published: August 2011

Certain metal nanoparticles exhibit the effect of localized surface plasmon resonance when interacting with light, based on collective oscillations of their conduction electrons. The interaction of this effect with molecules is of great interest for a variety of research disciplines, both in optics and in the life sciences. This paper attempts to describe and structure this emerging field of molecular plasmonics, situated between the molecular world and plasmonic effects in metal nanostructures, and demonstrates the potential of these developments for a variety of applications.
The ghosts of mammals past: biological and geographical patterns of global mammalian extinction across the Holocene
Authors: Turvey Samuel T. , Fritz Susanne A.
Published: August 2011

Although the recent historical period is usually treated as a temporal base-line for understanding patterns of mammal extinction, mammalian biodiversity loss has also taken place throughout the Late Quaternary. We explore the spatial, taxonomic and phylogenetic patterns of 241 mammal species extinctions known to have occurred during the Holocene up to the present day. To assess whether our understanding of mammalian threat processes has been affected by excluding these taxa, we incorporate extinct species data into analyses of the impact of body mass on extinction risk. We find that Holocene extinctions have been phylogenetically and spatially concentrated in specific taxa and geographical regions, which are often not congruent with those disproportionately at risk today. Large-bodied mammals have also been more extinction-prone in most geographical regions across the Holocene. Our data support the extinction filter hypothesis, whereby regional faunas from which susceptible species have already become extinct now appear less threatened; they may also suggest that different processes are responsible for driving past and present extinctions. We also find overall incompleteness and inter-regional biases in extinction data from the recent fossil record. Although direct use of fossil data in future projections of extinction risk is therefore not straightforward, insights into extinction processes from the Holocene record are still useful in understanding mammalian threat.
Ecology and evolution of mammalian biodiversity
Authors: Jones Kate E. , Safi Kamran
Published: August 2011

Mammals have incredible biological diversity, showing extreme flexibility in eco-morphology, physiology, life history and behaviour across their evolutionary history. Undoubtedly, mammals play an important role in ecosystems by providing essential services such as regulating insect populations, seed dispersal and pollination and act as indicators of general ecosystem health. However, the macroecological and macroevolutionary processes underpinning past and present biodiversity patterns are only beginning to be explored on a global scale. It is also particularly important, in the face of the global extinction crisis, to understand these processes in order to be able to use this knowledge to prevent future biodiversity loss and loss of ecosystem services. Unfortunately, efforts to understand mammalian biodiversity have been hampered by a lack of data. New data compilations on current species' distributions, ecologies and evolutionary histories now allow an integrated approach to understand this biodiversity. We review and synthesize these new studies, exploring the past and present ecology and evolution of mammalian biodiversity, and use these findings to speculate about the mammals of our future.
Labeling Mitochondria with MitoTracker Dyes
Authors: Chazotte Brad
Published: August 2011

INTRODUCTION

Membrane-potential-dependent dyes such as Rhodamine 123, tetramethylrhodamine methyl ester (TMRM), and tetramethylrhodamine ethyl ester (TMRE) are useful as long as the mitochondrion maintains its negative membrane potential. MitoTracker is a commercially available fluorescent dye (Invitrogen/Molecular Probes) that, like the aforementioned dyes, labels mitochondria within live cells utilizing the mitochondrial membrane potential. However, MitoTracker is chemically reactive, linking to thiol groups in the mitochondria. The dye becomes permanently bound to the mitochondria, and thus remains after the cell dies or is fixed. In addition, it can be used in experiments in which multiple labeling diminishes mitochondrial function. This protocol describes the labeling of mitochondria in live and fixed cells with MitoTracker dyes.
Calibration Protocols for Fluorescent Calcium Indicators: Figure 1.
Authors: Helmchen Fritjof
Published: August 2011

INTRODUCTION

Fluorescent calcium indicators are useful for measuring intracellular calcium ion concentrations. For a quantitative understanding of the physiological roles of Ca2+, fluorescence signals measured with calcium indicators have to be converted to intracellular free calcium concentration ([Ca2+]i). Most methods for converting a fluorescence signal to [Ca2+]i require the determination of a set of three calibration parameters: (Keff, Rmin, Rmax), (Kd, ΔF/Fmax, [Ca2+]rest), or (Kd, Rf, Fmax) or (Kapp, τmin, τmax). Here we describe the classical procedure for calibration of ratiometric measurements for both in vivo and in vitro calibrations, which is also useful for determining Kd and Rf. The [Ca2+]i dependence of the fluorescence ratio is measured using a set of at least three calibration solutions with known [Ca2+]i levels.
High-Throughput Illumina Strand-Specific RNA Sequencing Library Preparation
Authors: Zhong Silin , Joung Je-Gun , Zheng Yi , Chen Yun-ru , Liu Bao , Shao Ying , Xiang Jenny Z. , Fei Zhangjun , Giovannoni James J.
Published: August 2011

INTRODUCTION

Conventional Illumina RNA-Seq does not have the resolution to decode the complex eukaryote transcriptome due to the lack of RNA polarity information. Strand-specific RNA sequencing (ssRNA-Seq) can overcome these limitations and as such is better suited for genome annotation, de novo transcriptome assembly, and accurate digital gene expression analysis. This protocol describes a simple and robust method to generate ssRNA-Seq libraries for the Illumina sequencing platform. It has significantly increased the throughput to 96 libraries in a two-day preparation while simultaneously lowering the reagent costs to below ten dollars per library. It is compatible with both single-read and paired-end multiplex sequencing and, most importantly, its data can also be used with existing conventional RNA-Seq data. This is a significant advantage, because it enables researchers to switch to ssRNA-Seq even if a large amount of data has already been generated by the nonstrand specific methods.
Analysis of Dendrite Development in Drosophila Embryos
Authors: Shrestha Brikha R. , Grueber Wesley B.
Published: August 2011

INTRODUCTION

Dendrite morphological diversity helps to define the properties of neural circuits by influencing circuit organization and information processing. Dendrite development has been shown to be driven by a combination of cell-intrinsic and -extrinsic factors. However, much remains to be discovered about the cellular and molecular mechanisms that give rise to unique yet highly stereotyped dendrite arbors of diverse neuronal types. Work in the last decade has established the Drosophila system as an excellent model for studies of dendrite morphogenesis. This protocol describes the preparation of Drosophila embryos so that dendrite development can be assessed by confocal microscopy. The advantage of studies of embryonic stages is the relative ease of screening candidate genes and the ability to examine large numbers of neurons for phenotypes. This method is a basic and indispensable component of the set of techniques used for screening genes involved in dendrite morphogenesis.
Calibration of Fluorescent Calcium Indicators
Authors: Helmchen Fritjof
Published: August 2011

INTRODUCTION

During the past decades, many different fluorescent indicators have been developed for measuring intracellular ion concentrations. Of particular interest are fluorescent calcium indicators because of the fundamental role of Ca2+in various cellular processes such as contraction, secretion, and gene activation. For a quantitative understanding of the physiological roles of Ca2+, fluorescence signals measured with calcium indicators have to be converted to intracellular free calcium concentration ([Ca2+]i). Similarly, changes in [Ca2+]iand the underlying calcium fluxes need to be inferred from the corresponding fluorescence changes. This article describes the theoretical background and the various principal methods for the calibration of calcium imaging data.
Absolute airborne gravimetry: a feasibility study
Authors: Baumann H. , Klingelé E.E. , Marson I.
Published: August 2011

We report here the results obtained during a feasibility study that was pursued in order to evaluate the performances of absolute airborne gravimetry. In contrast to relative systems, which use spring‐type gravimeters, each measurement acquired by absolute systems is independent from the others and the instrument is not suffering from problems like instrumental drift, frequency response of the spring and variation of the calibration factor. After a validation of the dynamic performance of the experimental setup in a moving truck, a comparison between the experimental airborne data retrieved over the Swiss Alps and those obtained by ground upward continuation at flight altitude allow us to state that airborne absolute gravimetry is feasible. The first test flight shows a spatial resolution comparable to those obtained by relative airborne gravimetry. For a wavelength on the order of 12 km the absolute value of gravity can be evaluated with an uncertainty of 6.9 mGal.
The oral health of critically ill children: an observational cohort study
Authors: Ullman Amanda , Long Debbie , Lewis Peter
Published: August 2011

Aims and objectives.  This study will describe the oral health status of critically ill children over time spent in the paediatric intensive care unit, examine influences on the development of poor oral health and explore the relationship between dysfunctional oral health and healthcare‐associated infections.

Background.  The treatment modalities used to support children experiencing critical illness and the progression of critical illness may result in dysfunction in the oral cavity. In adults, oral health has been shown to worsen during critical illness as well as influence systemic health.

Design.  A prospective observational cohort design was used.

Method.  The study was undertaken at a single tertiary‐referral Paediatric Intensive Care Unit. Oral health status was measured using the Oral Assessment Scale and culturing oropharyngeal flora. Information was also collected surrounding the use of supportive therapies, clinical characteristics of the children and the occurrence of healthcare‐associated infections.

Results.  Of the 46 participants, 63% (n = 32) had oral dysfunction and 41% (n = 19) demonstrated pathogenic oropharyngeal colonisation during their critical illness. The potential systemic pathogens isolated from the oropharynx and included Candida sp., Staphylococcus aureus, Haemophilus influenzae, Enterococcus sp. and Pseudomonas aeruginosa. The severity of critical illness had a significant positive relationship (p < 0·05) with pathogenic and absent colonisation of the oropharynx. Sixty‐three percent of healthcare‐associated infections involved the preceding or simultaneous colonisation of the oropharynx by the causative pathogen.

Conclusions.  This study suggests paediatric oral health to be frequently dysfunctional and the oropharynx to repeatedly harbour potential systemic pathogens during childhood critical illness.

Relevance to clinical practice.  Given the frequency of poor oral health during childhood critical illness in this study and the subsequent potential systemic consequences, evidence based oral hygiene practices should be developed and validated to guide clinicians when nursing critically ill children.
Family life and the impact of previous and present residential and day care support for children with major cognitive and behavioural challenges: a dilemma for services and policy
Authors: Brown R. I. , Geider S. , Primrose A. , Jokinen N. S.
Published: August 2011

Introduction  Since the development of inclusion and integration, parents have increasingly become the major, and sometimes the only, carers of their children with disabilities. Many families speak of stress and frustration with service and community support, and some have turned to residential and specialised day care services to overcome challenges. The need for, and experiences of, such services needs to be examined not just in terms of the child but also in terms of family impact.

Method  The study involved interviewing parents on a 1:1 basis and in a focus group to examine the perceptions of family life, along with their later experience of full‐time day and residential care. The children had multiple diagnoses of intellectual disability plus major challenging behaviour.

Results  The results describe the major challenges facing families when the children spent most or all of their time at home. This contrasted starkly with the changes in perceived family life once the children were in residential care and day support. Improvements in behaviour of the children were noted and children began to return home for periods of time. Parent noted increased stability of family life, involvement of siblings in more normal community life and increased opportunities for spouses to function more effectively in one or more life domains. Family members perceived a major improvement in overall quality of life.

Discussion  The results are consistent with findings in other family quality of life studies in terms of family experience, and the types of challenges faced when the child was at home, including when excluded from the regular education system. Extensive support in raising children is required by parents and without this there is a deleterious effect on family life. Many families experienced exclusion within their home communities. Full‐time day and residential support were provided, allowing the family to function more effectively and later to provide a more natural home environment for the child. The article raises questions of policy concerning family well‐being, as well as the needs of the child.
Concept of death and perceptions of bereavement in adults with intellectual disabilities
Authors: McEvoy J. , MacHale R. , Tierney E.
Published: August 2011

Background  Bereavement is potentially a time of disruption and emotional distress. For individuals with an intellectual disability (ID), a limited understanding of the concept of death may exacerbate this distress. The aim of the present study was to investigate how individuals with ID understand and explain death and make sense of life without the deceased.

Method  Thirty‐four people with ID were interviewed using simple vignettes describing death‐related incidents. Participants were asked about the causes of death, the status of the body after death and whether all living things die. In addition, participants were asked about reactions to death and for their views on post‐bereavement support.

Results  Nearly one quarter of participants had a full understanding and over two‐thirds a partial understanding of the concept of death. Death comprehension was positively correlated with cognitive ability and adaptive functioning. While cause of death was predominantly associated with illness and old age, participants viewed death as final and understood that all living things die. The role of religious beliefs was also found to be important for many participants.

Conclusions  The results support earlier findings that suggest people with ID have only a partial understanding of the concept of death leaving them vulnerable to factually incorrect thoughts. The study highlights the considerable scope for making sense of death using religious and spiritual themes and emphasises the need for teaching individuals biological explanations of the life cycle. The results also provide some insight into the views of individuals with ID for carers involved in providing post‐bereavement support.
SPATULA and ALCATRAZ, are partially redundant, functionally diverging bHLH genes required for Arabidopsis gynoecium and fruit development
Authors: Groszmann Michael , Paicu Teodora , Alvarez John P. , Swain Steve M. , Smyth David R.
Published: August 2011

The Arabidopsis gynoecium is a complex organ that facilitates fertilization, later developing into a dehiscent silique that protects seeds until their dispersal. Identifying genes important for development is often hampered by functional redundancy. We report unequal redundancy between two closely related genes, SPATULA (SPT) and ALCATRAZ (ALC), revealing previously unknown developmental roles for each. SPT is known to support septum, style and stigma development in the flower, whereas ALC is involved in dehiscence zone development in the fruit. ALC diverged from a SPT‐like ancestor following gene duplication coinciding with the At‐β polyploidy event. Here we show that ALC is also involved in early gynoecium development, and SPT in later valve margin generation in the silique. Evidence includes the increased severity of early gynoecium disruption, and of later valve margin defects, in spt‐alc double mutants. In addition, a repressive version of SPT (35S:SPT‐SRDX) disrupts both structures. Consistent with redundancy, ALC and SPT expression patterns overlap in these tissues, and the ALC promoter carries two atypical E‐box elements identical to one in SPT required for valve margin expression. Further, SPT can heterodimerize with ALC, and 35S:SPT can fully complement dehiscence defects in alc mutants, although 35S:ALC can only partly complement spt gynoecium disruptions, perhaps associated with its sequence simplification. Interactions with FRUITFULL and SHATTERPROOF genes differ somewhat between SPT and ALC, reflecting their different specializations. These two genes are apparently undergoing subfunctionalization, with SPT essential for earlier carpel margin tissues, and ALC specializing in later dehiscence zone development.
Relationship between polymorphisms in the 5′ leader cistron, positions 16 and 27 of the adrenergic β2 receptor gene and asthma in a Han population from southwest China
Authors: FU WEI‐PING , ZHAO ZHI‐HUAN , ZHONG LI , SUN CHANG , FANG LI‐ZHOU , LIU LING , ZHANG JIAN‐QING , WANG LEI , SHU JING‐KUI , WANG XU‐MING , DAI LU‐MING
Published: August 2011

Background and objective:  Adrenergic β2 receptors (ADRB2) play an important role in regulating pulmonary function. Many previous studies have investigated possible associations between polymorphisms in the ADRB2 gene and asthma, but have yielded conflicting results. Furthermore, little is known regarding the possible role of the Arg19Cys polymorphism in susceptibility to asthma among Chinese.

Methods:  This case–control association study involved 238 patients with asthma and 265 healthy subjects from a Han population in southwest China. For all subjects, the 5′ leader cistron Arg19Cys, Arg16Gly and Gln27Glu polymorphisms in the ADRB2 gene were characterized by direct sequencing. Genotype, allele and haplotype frequencies were determined. In addition, to evaluate the association between the ADRB2 polymorphisms and lung function, bronchodilator response to inhaled β2 agonists (400 µg of albuterol) was assessed in the asthmatic patients.

Results:  There were no significant differences in genotype or allele frequencies for the three ADRB2 polymorphisms between the two cohorts. The Arg19/Arg16/Gln27 haplotype was more frequent among asthmatic patients than control subjects (odds ratio 2.24, 95% confidence interval (CI): 1.05–4.73, P = 0.04). Moreover, the Arg19/Cys19 genotype was associated with a lower FEV1% (mean difference −4.5, 95% CI: −12.5 to 3.6, P = 0.02) and FEV1/FVC (mean difference 8.9, 95% CI: 8.5–9.4, P = 0.01). The bronchodilator response to albuterol was also marginally lower in individuals who were homozygous for the Arg19 genotype (mean difference 4.2, 95% CI: 3.7–4.8, P = 0.03).

Conclusions:  The Arg19/Cys19 genotype was an independent risk factor for lower FEV1% and FEV1/FVC. Asthmatic patients with the Arg19/Arg19 genotype showed decreased responsiveness to albuterol. Furthermore, the Arg19/Arg16/Gln27 haplotype may contribute to increased susceptibility to asthma in the Chinese population.
Trans‐obturator colonic suspension during Altemeier’s operation for full‐thickness rectal prolapse: preliminary results with a new technique
Authors: Boccasanta P. , Venturi M. , Spennacchio M. , Fratus G. , Despini L. , Roviaro G.
Published: August 2011

Aim  With the aim of reducing recurrence after perineal surgery for full‐thickness rectal prolapse, a new operation consisting of a trans‐obturator colonic suspension during Altemeier’s operation has been developed.

Method  Eighteen women with full‐thickness rectal prolapse were examined clinically, with validated quality of life and continence scores, colonoscopy, anorectal manometry, anal EMG and sacral reflex latency. Ten had a newly diagnosed and eight a recurrent prolapse. The Altemeier operation was combined with a levatorplasty in all cases using two porcine collagen prostheses sutured to the descending colon and passed through the trans‐obturator space bilaterally. The operation was completed by a manual or stapled colo‐anal anastomosis. Clinical examination, with quality of life and continence scores, anorectal manometry, EMG and sacral reflex latency, was scheduled during follow up, with the recurrence of prolapse as the primary outcome measure.

Results  There were no recurrences at 30 months. There was no mortality and no complications. All patients experienced significant improvement in quality of life and faecal continence scores (P < 0.01). Surgery did not affect anorectal pressures or sacral reflex latencies.

Conclusion  The new technique appears to be relatively easy to perform and is complication free with no recurrence after a short period of follow up. A larger study with appropriate controls and longer follow up is now needed to assess its real effectiveness in reducing the risk of recurrence.
Production of recombinant human granulocyte macrophage‐colony stimulating factor in rice cell suspension culture with a human‐like N‐glycan structure
Authors: Shin Yun‐Ji , Chong Yun‐Jo , Yang Moon‐Sik , Kwon Tae‐Ho
Published: August 2011

The rice α‐amylase 3D promoter system, which is activated under sucrose‐starved conditions, has emerged as a useful system for producing recombinant proteins. However, using rice as the production system for therapeutic proteins requires modifications of the N‐glycosylation pattern because of the potential immunogenicity of plant‐specific sugar residues. In this study, glyco‐engineered rice were generated as a production host for therapeutic glycoproteins, using RNA interference (RNAi) technology to down‐regulate the endogenous α‐1,3‐fucosyltransferase (α‐1,3‐FucT) and β‐1,2‐xylosyltransferase (β‐1,2‐XylT) genes. N‐linked glycans from the RNAi lines were identified, and their structures were compared with those isolated from a wild‐type cell suspension. The inverted‐repeat chimeric RNA silencing construct of α‐1,3‐fucosyltransferase and β‐1,2‐xylosyltransferase (Δ3FT/XT)‐9 glyco‐engineered line with significantly reduced core α‐1,3‐fucosylated and/or β‐1,2‐xylosylated glycan structures was established. Moreover, levels of plant‐specific α‐1,3‐fucose and/or β‐1,2‐xylose residues incorporated into recombinant human granulocyte/macrophage colony‐stimulating factor (hGM‐CSF) produced from the N44 + Δ3FT/XT‐4 glyco‐engineered line co‐expressing ihpRNA of Δ3FT/XT and hGM‐CSF were significantly decreased compared with those in the previously reported N44‐08 transgenic line expressing hGM‐CSF. None of the glyco‐engineered lines differed from the wild type with respect to cell division, proliferation or ability to secrete proteins into the culture medium.
Managers’ Private Information, Investor Underreaction and Long‐Run SEO Performance
Authors: Bilinski Pawel , Strong Norman
Published: August 2011

For a sample of 2,879 SEOs by US stocks from 1970 to 2004, this paper decomposes an average three‐year post‐issue buy‐and‐hold abnormal return of −25.9% (relative to size‐ and B/M‐matched non‐issuing stocks) into two components. One component, representing 41% of the total, is due to lower risk exposure. The second component, representing the remaining 59%, is abnormal performance related to the surprise element of the issue decision, which the paper attributes to managers’ private information that the market does not incorporate into the announcement return. This second component results in abnormal returns during the 16 months after the offering.
What characterizes changing‐state speech in affecting short‐term memory? An EEG study on the irrelevant sound effect
Authors: Schlittmeier Sabine J. , Weisz Nathan , Bertrand Olivier
Published: August 2011

The irrelevant sound effect (ISE) describes reduced verbal short‐term memory during irrelevant changing‐state sounds which consist of different and distinct auditory tokens. Steady‐state sounds lack such changing‐state features and do not impair performance. An EEG experiment (N=16) explored the distinguishing neurophysiological aspects of detrimental changing‐state speech (3‐token sequence) compared to ineffective steady‐state speech (1‐token sequence) on serial recall performance. We analyzed evoked and induced activity related to the memory items as well as spectral activity during the retention phase. The main finding is that the behavioral sound effect was exclusively reflected by attenuated token‐induced gamma activation most pronounced between 50–60 Hz and 50–100 ms post‐stimulus onset. Changing‐state speech seems to disrupt a behaviorally relevant ongoing process during target presentation (e.g., the serial binding of the items).
How large the sin? A study of the event related potentials elicited by errors of varying magnitude
Authors: Arbel Yael , Donchin Emanuel
Published: August 2011

We report the results of an experiment designed to elucidate the extent to which the error related ERP components are affected by response and stimulus similarity. We examined the ERPs under varying degrees of mismatch between the representations of actual and appropriate responses. We replicated the design used in an earlier study, which demonstrated that response similarity rather than stimulus similarity affected the amplitude of the error related negativity (ERN). We report the results of a spatial‐temporal principal component analysis (PCA), which indicates that response similarity affects the amplitudes of the ERN and the fronto‐central positive component, but not those of the P300 and the frontal negativity. The results provide evidence to suggest that the ERN and the proceeding positive deflection are error related and are sensitive to the degree of the committed error, whereas the P300 and the frontal negativity are not.
Event‐related potentials increase the discrimination performance of the autonomic‐based concealed information test
Authors: Matsuda Izumi , Nittono Hiroshi , Ogawa Tokihiro
Published: August 2011

The concealed information test (CIT) assesses an examinee's crime‐relevant memory on the basis of physiological differences between crime‐relevant and irrelevant items. The CIT based on autonomic measures has been used for criminal investigations, while the CIT based on event‐related potentials (ERPs) has been suggested as a useful alternative. To combine these two methods, we developed a quantification method of ERPs measured in the autonomic‐based CIT where each item was repeated only 5 times. Results showed that the peak amplitude of the ERP difference wave between crime‐relevant and irrelevant items could discriminate between guilty and innocent participants effectively even when only 5 trials were used for averaging. This ERP measure could detect some participants who were missed by the autonomic measures. Combining the ERP and autonomic measures significantly improved the discrimination performance of the autonomic‐based CIT.
Targeting synaptic pathology in multiple sclerosis: fingolimod to the rescue?
Authors: Gillingwater Thomas H
Published: August 2011

Multiple sclerosis (MS) is an inflammatory disorder affecting the brain and spinal cord. Major hallmarks of MS typically include inflammation, demyelination and axon degeneration, although recent studies have also implicated synaptic dysfunction and degeneration in disease pathogenesis. The discovery that treatment with the orally active immunomodulatory drug fingolimod (FTY720) confers benefits in animal models and human patients has opened up new avenues for the treatment of MS. In the present issue of the BJP, Rossi and colleagues used a mouse model of MS [experimental autoimmune encephalomyelitis (EAE)] to provide new evidence suggesting that fingolimod may target MS symptoms, at least in part, by ameliorating synaptic dysfunction. They demonstrated that fingolimod reversed modifications in glutamatergic transmission found in the striatum of EAE mice, accompanied by a reduction in the severity of dendritic spine loss. This report suggests that fingolimod treatment can have beneficial effects on synaptic pathology in MS, raising the intriguing possibility that fingolimod treatment may also be advantageous in other diseases of the nervous system where inflammation and synaptic pathology contribute to disease pathogenesis.

LINKED ARTICLE This article is a commentary on Rossi et al., pp. 861–869 of this issue. To view this paper visit http://dx.doi.org/10.1111/j.1476‐5381.2011.01579.x
Conformational switches in the VPAC1 receptor
Authors: Langer Ingrid
Published: August 2011

The vasoactive intestinal peptide receptor 1 (VPAC1) belongs to family B of GPCRs and is activated upon binding of vasoactive intestinal peptide (VIP) and pituitary AC‐activating polypeptide neuropeptides. Widely distributed throughout body, VPAC1 plays important regulatory roles in human physiology and physiopathology. Like most members of the GPCR‐B family, VPAC1 receptor is predicted to follow the actual paradigm of a common ‘two‐domain’ model of natural ligand action. However the precise structural basis for ligand binding, receptor activation and signal transduction are still incompletely understood due in part to the absence of X‐ray crystal structure of the whole receptor and to significant structural differences with the most extensively studied family of receptor, the GPCR‐A/rhodopsin family. Here, we try to summarize the current knowledge of the molecular mechanisms involved in VPAC1 receptor activation and signal transduction. This includes search for amino acids involved in the two‐step process of VIP binding, in the stabilization of VPAC1 inactive and active conformations, and in binding and activation of G proteins.

LINKED ARTICLES This article is part of a themed section on Secretin Family (Class B) G Protein‐Coupled Receptors. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.166.issue‐1
Atrial Fibrillation and Risk of Dementia: A Prospective Cohort Study
Authors: Dublin Sascha , Anderson Melissa L. , Haneuse Sebastien J. , Heckbert Susan R. , Crane Paul K. , Breitner John C. S. , McCormick Wayne , Bowen James D. , Teri Linda , McCurry Susan M. , Larson Eric B.
Published: August 2011

OBJECTIVES: To determine whether atrial fibrillation (AF) is associated with risk of incident dementia or Alzheimer's disease (AD), beyond its effect on stroke.

DESIGN: Prospective cohort study.

SETTING: An integrated healthcare delivery system.

PARTICIPANTS: A population‐based sample of 3,045 community‐dwelling adults aged 65 and older without dementia or clinical stroke followed from 1994 to 2008.

MEASUREMENTS: AF was identified from health plan electronic data using International Classification of Diseases, Ninth Revision, codes from inpatient and outpatient encounters. Covariates came from self‐report, study measures, and health plan data. Participants were screened every 2 years using the Cognitive Abilities Screening Instrument (range 0–100), with detailed neuropsychological and clinical assessment of those scoring less than 86. A multidisciplinary consensus committee determined diagnoses of all‐cause dementia and possible or probable AD using standard research criteria.

RESULTS: AF was present in 132 (4.3%) participants at baseline and was diagnosed in 370 (12.2%) more over a mean of 6.8 years of follow‐up; 572 participants (18.8%) developed dementia (449 with AD). The adjusted hazard ratio associated with AF was 1.38 (95% confidence interval (CI)=1.10–1.73) for all‐cause dementia and 1.50 (95% CI=1.16–1.94) for possible or probable AD. Results were similar for participants with and without clinically recognized stroke during follow‐up and in sensitivity analyses examining only probable AD.

CONCLUSION: AF is associated with higher risk of developing AD and dementia. Future studies should examine whether specific treatments, including optimal anticoagulation, can decrease this risk.