bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of the background toroidal rotation on particle and heat turbulent transport in tokamak plasmas
Authors: Camenen Y. , Peeters A. G. , Angioni C. , Casson F. J. , Hornsby W. A. , Snodin A. P. , Strintzi D.
Published: January 2009

Recent developments in the gyrokinetic theory have shown that, in a toroidal device, the Coriolis drift associated with the background plasma rotation significantly affects the small scale instabilities [A. G. Peeters et al., Phys. Rev. Lett. 98, 265003 (2007)]. The later study, which focuses on the effect of the Coriolis drift on toroidal momentum transport is extended in the present paper to heat and particle transport. It is shown numerically using the gyrokinetic flux-tube code GKW [A. G. Peeters and D. Strintzi, Phys. Plasmas 11, 3748 (2004)], and supported analytically, that the Coriolis drift and the parallel dynamics play a similar role in the coupling of density, temperature, and velocity perturbations. The effect on particle and heat fluxes increases with the toroidal rotation (directly) and with the toroidal rotation gradient (through the parallel mode structure), depends on the direction of propagation of the perturbation, increases with the impurity charge number and with the impurity mass to charge number ratio. The case of very high toroidal rotation, relevant to spherical tokamaks, is investigated by including the effect of the centrifugal force in a fluid model. The main effect of the centrifugal force is to decrease the local density gradient at the low field side midplane and to add an extra contribution to the fluxes. The conditions for which the inertial terms significantly affect the heat and particle fluxes are evidenced.
Competition between π and σ hydrogen bonds and conformational probing of 2-orthofluorophenylethanol by low-and high-resolution electronic spectroscopy
Authors: Karaminkov R. , Chervenkov S. , Neusser H. J. , Ramanathan V. , Chakraborty T.
Published: January 2009

The flexible model molecule 2-orthofluorophenylethanol has been investigated by laser-induced fluorescence, and low- and high-resolution resonance-enhanced two-photon ionization spectroscopy in combination with high-level ab initio quantum chemistry calculations. One dominant conformation has been identified in the cold molecular beam corresponding to the most stable theoretically predicted gauche structure stabilized by an intramolecular OH⋯π hydrogen bond. A tentative assignment of a higher-lying gauche conformer present in the molecular beam separated by high potential barriers from the most stable one has been made. The missing other higher-energy theoretically predicted conformations most likely relax to the most stable ones during the process of the adiabatic expansion. The good agreement between the experimental and theoretical results demonstrates that even in the case of a substitution with an electronegative atom at the ortho position, bringing about a significant redistribution of the electron density in the benzene ring and providing a convenient binding site for the formation of a competing OH⋯F σ hydrogen bond, the nonclassical OH⋯π bond remains the preferred binding motif for the most stable conformer.
Theoretical description of charge migration with a single Slater-determinant and beyond
Authors: Kuleff Alexander I. , Dreuw Andreas
Published: January 2009

Triggered by the interest to study charge migration in large molecular systems, a simple methodology has recently been proposed based on straightforward density functional theory calculations. This approach describes the time evolution of the initially created hole density in terms of the time evolution of the ionized highest occupied molecular orbital (HOMO). Here we demonstrate that this time-dependent analog of Koopmans’ theorem is not valid, and instead of the time evolution of the HOMO, the time evolution of the orbitals that remain occupied in the cation determines the evolution of the initially created hole in the framework of time-dependent single-determinant theories. Numerical examples underline that for a proper description of charge migration processes, an explicit treatment of the electron correlation is indispensable. Moreover, they also demonstrate that the attempts to describe charge migration based on Kohn–Sham density functional theory using conventional exchange-correlation functionals are doomed to fail due to the well-known self-interaction error.
Visible and ultraviolet upconversion emission in LiNbO3 triply doped with Tm3+, Yb3+, and Nd3+
Authors: Li Ai-Hua , Zheng Zhi-Ren , Lü Qiang , Sun Liang , Liu Wei-Long , Wu Wen-Zhi , Yang Yan-Qiang , Lü Tian-Quan
Published: January 2009

Visible and ultraviolet upconversion (UC) emission is observed under 800 nm femtosecond laser excitation in LiNbO3 crystals triply doped with Tm3+, Yb3+, and Nd3+ at room temperature. Energy transfer (ET) from Nd3+ to Yb3+ then to Tm3+ is very important in this UC emission process. The overlapping between the emissions of D12→F34 and G14→H36, which makes up of blue emission band, is confirmed by transient investigation. From the pump energy dependence investigation, it is known that the dominant populating mechanism for the G14 state is the two-photon process, and that for D12 is the three-photon process. In our UC emission model, the G14 state is populated by the ET of F25/2(Yb3+)+H34(Tm3+)→F27/2(Yb3+)+G14(Tm3+), D12 state is populated by the ET of F32+H34→D12+H36 among Tm3+ ions. For LiNbO3 crystals doped with Tm3+ to the concentration of 0.9 mol %, the measured lifetimes of G14 and D12 are ∼80 and 4 μs.
Gain recovery in an electric oxygen-iodine laser
Authors: Zimmerman J. W. , Benavides G. F. , Palla A. D. , Woodard B. S. , Carroll D. L. , Verdeyen J. T. , Solomon W. C.
Published: January 2009

Recent investigations of an electric oxygen-iodine laser system have shown that computational modeling overpredicts the experimentally measured power output for similar gain conditions. This discrepancy is potentially due to an unknown reaction that competes with the forward pumping of I(P21/2) by O2(a Δ1). Measurements of gain recovery downstream of an operating laser cavity were performed. Modeling of this experiment shows that reducing the forward pumping rate by an effective factor of approximately 4 to simulate a competing mechanism results in the computational modeling matching the experimental gain recovery measurements, and in improved agreement between the measured and modeled laser power extraction.
Investigation of interfacial interaction and structural transition for epoxy/nanotube composites by positron annihilation lifetime spectroscopy
Authors: Zhou Wei , Wang Junjun , Gong Zhenli , Gong Jing , Qi Ning , Wang Bo
Published: January 2009

Positron annihilation lifetime spectroscopy was employed to study the effect of amine modification on interfacial interaction and structural transition for epoxy/multiwalled carbon nanotube (MWNT) composites. Temperature dependence of orthopositronium lifetimes suggests that sample with amine-modified MWNTs possesses the highest glass transition temperature compared with unmodified samples and neat epoxy resin, which indicates that stronger interfacial interactions exist between epoxy matrix and amine-modified MWNTs, as a result of the covalent bonds and other weak forces. This is testified by interaction parameter β calculated in terms of the positron annihilation parameter.
Probing radical kinetics in the afterglow of pulsed discharges by absorption spectroscopy with light emitting diodes: Application to BCl radical
Authors: Vempaire D. , Cunge G.
Published: January 2009

Measuring decay rates of radical densities in the afterglow of pulsed plasmas is a powerful approach to determine their gas phase and surface loss kinetics. We show that this measurement can be achieved by absorption spectroscopy with low cost and simple apparatus by using light emitting diodes as a light source. The feasibility is demonstrated by monitoring BCl radicals in pulsed low pressure high-density BCl3 plasmas. It is shown that BCl is lost both in the gas phase by reacting with Cl2 with a cross section of 9 Å2 and in the chamber walls with a sticking coefficient of about 0.3.
Terahertz wave generation from gas plasma using a phase compensator with attosecond phase-control accuracy
Authors: Dai Jianming , Zhang X.-C.
Published: January 2009

We report the use of a precise phase compensator for the generation of intense terahertz waves from laser-induced gas plasma excited by a femtosecond pulse (ω) and its second harmonic (2ω) at both close contact and standoff distances. The attosecond accuracy phase-control capability of the device enables further optimization of the terahertz emission from gas plasma and elimination of the temporal walkoff between the ω and 2ω pulses traveling in dispersive media, resulting in intense terahertz generation at a distance of over 100 m by sending the optical beams far away and focusing them locally.
Microwave-induced water flows in microsystems
Authors: Ramos A. , Robles A. , García-Sánchez P. , Freire M. J.
Published: January 2009

Alternating current electric fields are of increasing importance for the development of microfluidic pumps. We report how microwave fields can induce water flow in microsystems, irrespective of saline concentration. A drop of water is placed on two parallel coplanar microelectrodes that are energized by a microwave generator. Fluid flow is observed and the fluid velocity is about the same for two electrolytes with very different saline concentrations. Electrically induced gradients of temperature produce spatial variations in mass density and dielectric permittivity leading, respectively, to buoyancy and dielectric forces in the liquid. The observed fluid flow patterns demonstrate that both effects are taking place at different length scales: the dielectric forces dominate at lengths of the order of 100 μm or smaller, while buoyancy dominates around 1 mm.
Transmission and reflection phase gratings formed in azo-dye-doped chiral nematic liquid crystals
Authors: Sasaki Tomoyuki , Emoto Akira , Shioda Tatsutoshi , Ono Hiroshi
Published: January 2009

Transmission and reflection gratings were simultaneously formed in azo-dye-doped chiral nematic liquid crystals (N∗LCs) with planar alignment. The formation process is based on a phototuning of the Bragg reflection band of the N∗LC. The helical pitch of the photoreactive N∗LC was spatially controlled with intensity variation of interference light. The resultant periodic structure showed both transmissive and reflective diffractions due to the spatially modulated light intensities. The observed dependence of diffraction efficiencies on the polarization states of the probe beam was well explained by considering a spatial modulation of the helical pitch.
GaSb-based, 2.2 μm type-I laser fabricated on GaAs substrate operating continuous wave at room temperature
Authors: Rodriguez J. B. , Cerutti L. , Tournié E.
Published: January 2009

We report on a Sb-based type-I laser grown on GaAs substrate, emitting continuous wave at room temperature around 2.2 μm. The device was grown using solid-source molecular beam epitaxy and comprised two GaInAsSb quantum wells embedded in AlGaAsSb barriers. Despite the large lattice mismatch, a good crystalline quality was obtained, and processed devices operated continuous wave up to 50 °C with threshold current densities in the range of 1.5–2.2 kA/cm2. An optical output power of 3.7 mW was obtained at 20 °C.
Interfacial reactions and resistive switching behaviors of metal/NiO/metal structures
Authors: Phark S. H. , Jung R. , Chang Y. J. , Noh T. W. , Kim D.-W.
Published: January 2009

Ag/NiO/Pt structures did (did not) exhibit reproducible resistive switching when a positive bias was applied to the Pt (Ag) electrode. X-ray photoemission spectra revealed that ultrathin NiO films on Pt (Ag) layers did (did not) undergo reversible chemical state change during heat treatment in a vacuum and oxygen ambient. Such differences in interfacial chemical interaction may affect filament formation and rupture processes near the electrode and hence alter the resistive switching behaviors.
The p53-cathepsin axis cooperates with ROS to activate programmed necrotic death upon DNA damage
Authors: Tu Ho-Chou , Ren Decheng , Wang Gary X. , Chen David Y. , Westergard Todd D. , Kim Hyungjin , Sasagawa Satoru , Hsieh James J.-D. , Cheng Emily H.-Y.
Published: January 2009

Three forms of cell death have been described: apoptosis, autophagic cell death, and necrosis. Although genetic and biochemical studies have formulated a detailed blueprint concerning the apoptotic network, necrosis is generally perceived as a passive cellular demise resulted from unmanageable physical damages. Here, we conclude an active de novo genetic program underlying DNA damage-induced necrosis, thus assigning necrotic cell death as a form of “programmed cell death.” Cells deficient of the essential mitochondrial apoptotic effectors, BAX and BAK, ultimately succumbed to DNA damage, exhibiting signature necrotic characteristics. Importantly, this genotoxic stress-triggered necrosis was abrogated when either transcription or translation was inhibited. We pinpointed the p53-cathepsin axis as the quintessential framework underlying necrotic cell death. p53 induces cathepsin Q that cooperates with reactive oxygen species (ROS) to execute necrosis. Moreover, we presented the in vivo evidence of p53-activated necrosis in tumor allografts. Current study lays the foundation for future experimental and therapeutic discoveries aimed at “programmed necrotic death.”
Heme uptake across the outer membrane as revealed by crystal structures of the receptor–hemophore complex
Authors: Krieg Stefanie , Huché Frédéric , Diederichs Kay , Izadi-Pruneyre Nadia , Lecroisey Anne , Wandersman Cécile , Delepelaire Philippe , Welte Wolfram
Published: January 2009

Gram-negative bacteria use specific heme uptake systems, relying on outer membrane receptors and excreted heme-binding proteins (hemophores) to scavenge and actively transport heme. To unravel the unknown molecular details involved, we present 3 structures of the
Serratia marcescens
receptor HasR in complex with its hemophore HasA. The transfer of heme over a distance of 9 Å from its high-affinity site in HasA into a site of lower affinity in HasR is coupled with the exergonic complex formation of the 2 proteins. Upon docking to the receptor, 1 of the 2 axial heme coordinations of the hemophore is initially broken, but the position and orientation of the heme is preserved. Subsequently, steric displacement of heme by a receptor residue ruptures the other axial coordination, leading to heme transfer into the receptor.
DJ-1/PARK7 is an important mediator of hypoxia-induced cellular responses
Authors: Vasseur Sophie , Afzal Samia , Tardivel-Lacombe Joël , Park David S. , Iovanna Juan Lucio , Mak Tak Wah
Published: January 2009

In cancer, DJ-1/PARK7 acts as an oncogene that drives Akt-mediated cell survival. Although amplification of DJ-1 has been described in several types of tumors, the mechanistic basis of DJ-1's oncogenic effect remains incompletely understood. A tumor's ability to adapt to hypoxia is absolutely critical for its survival and progression, and this adaptation is largely mediated by the transcription factor HIF1. The stabilization of HIF1 subunits during hypoxia is at least partly dependent on the PI3K/Akt/mTOR pathway. We hypothesized that DJ-1, a positive regulator of Akt when over-expressed, might be involved in regulating HIF1 transcriptional activity under hypoxic conditions. Our results show that loss of DJ-1 in human cell lines and transformed mouse fibroblasts decreases the transcription of a variety of HIF1-responsive genes during hypoxia. Moreover, DJ-1 expression is critical for the Akt and mTOR activities that sustain HIF1 stability. Surprisingly, DJ-1 also regulates the activity of the metabolic sensor AMPK, especially during hypoxia. Finally, DJ-1 appears to protect cells against hypoxia-induced cell death and is required for their adaptation to severe hypoxic stress. Our work positions DJ-1 as an upstream activator of HIF1 function in cancer cells and establishes that DJ-1's oncogenic activity stems from its ability to increase a cell's resistance to hypoxic stress through DJ-1's regulatory effects on mTOR and AMPK. The discovery of these functions of DJ-1 strengthens the case for the development of therapeutics that target DJ-1 activity in cancer cells.
Increasing Psychology Students' Satisfaction with Preparedness through a Professional Issues Course
Authors: Roscoe Lauren J. , Strapp Chehalis M.
Published: January 2009

The current studies evaluated a capstone course, Professional Issues in Psychology, designed to prepare students for a career in psychology. The first study examined course topics and student evaluations of assignments across 4 terms. Overall, students reported that the assignments were very helpful. The second study found that students who had completed the course felt more satisfied with their preparation for graduate school and for entering the job market relative to a sample of graduating seniors who did not take the course. These results suggest that the course is associated with increased self-efficacy for entering the job market and applying to graduate school. Suggestions for developing a careers capstone course are discussed.
Accuracy of parent identification of stuttering occurrence
Authors: Einarsdóttir Jóhanna , Ingham Roger
Published: January 2009

Background: Clinicians rely on parents to provide information regarding the onset and development of stuttering in their own children. The accuracy and reliability of their judgments of stuttering is therefore important and is not well researched.

Aim: To investigate the accuracy of parent judgements of stuttering in their own children's speech when compared with judgements made by the parents of normally fluent children and experienced clinicians.

Methods & Procedures: Twenty parents of children who stutter made judgements of stuttering during repeated presentations of 3‐min audio‐visual samples of their children. Twenty control parents of children (age and gender matched) who do not stutter also assessed the children who stutter speech samples.

Outcomes & Results: The parents of both the children who stutter and those who do not stutter displayed high levels of judgement accuracy (parents, of children who stutter percentage agreement mean (standard deviation) = 90.9 (6.02); parents of children who do not stutter = 86.4 (9.7)) and consistency (90.3–90.6%) in judging stuttering in young children. But the parents of children who stutter showed significantly higher levels of accuracy (t(59) = 4.63, p<0.0001; d = 0.8) in judging stuttered intervals than the children who do not stutter parents.

Conclusions & Implications: Parents of children who stutter may be both accurate and reliable in identifying brief intervals of speech containing stuttering and non‐stuttering in their own children.
An exploratory study of linguistic–colour associations across languages in multilingual synaesthetes
Authors: Barnett Kylie J. , Feeney Joanne , Gormley Michael , Newell Fiona N.
Published: January 2009

In one of the most common forms of synaesthesia, linguistic–colour synaesthesia, colour is induced by stimuli such as numbers, letters, days of the week, and months of the year. It is not clear, however, whether linguistic–colour synaesthesia is determined more by higher level semantic information—that is, word meaning—or by lower level grapheme or phoneme structure. To explore this issue, we tested whether colour is consistently induced by grapheme or phoneme form or word meaning in bilingual and trilingual linguistic–colour synaesthetes. We reasoned that if the induced colour was related to word meaning, rather than to the acoustic or visual properties of the words, then the induced colours would remain consistent across languages. We found that colours were not consistently related to word meaning across languages. Instead, induced colours were more related to form properties of the word across languages, particularly visual structure. However, the type of inducing stimulus influenced specific colour associations. For example, colours to months of the year were more consistent across languages than were colours to numbers or days of the week. Furthermore, the effect of inducing stimuli was also associated with the age of acquisition of additional languages. Our findings are discussed with reference to a critical period in language acquisition on synaesthesia.
Short Article: Is Advance Reconfiguration in Voluntary Task Switching Affected by the Design Employed?
Authors: Liefooghe Baptist , Demanet Jelle , Vandierendonck André
Published: January 2009

In task switching, when the amount of preparation time is increased, a reduction in switch cost or RISC effect is observed. This RISC effect is frequently attributed to advance reconfiguration processes. In the explicit task-cueing procedure, RISC effects are observed when varying the preparation time within participants but not when varying the preparation time across participants—a finding suggesting that RISC effects in the explicit task-cueing procedure are restricted to specific designs. The present study investigated RISC effects in voluntary task switching and compared RISC effects in a within-subjects design with RISC effects in a between-subjects design. Our results indicate that RISC effects are present in both designs. We conclude that advance reconfiguration in voluntary task switching is robust.
Short article: Size matters: Bigger is faster
Authors: Sereno Sara C. , O'Donnell Patrick J. , Sereno Margaret E.
Published: January 2009

A largely unexplored aspect of lexical access in visual word recognition is “semantic size”—namely, the real-world size of an object to which a word refers. A total of 42 participants performed a lexical decision task on concrete nouns denoting either big or small objects (e.g., bookcase or teaspoon). Items were matched pairwise on relevant lexical dimensions. Participants’ reaction times were reliably faster to semantically “big” versus “small” words. The results are discussed in terms of possible mechanisms, including more active representations for “big” words, due to the ecological importance attributed to large objects in the environment and the relative speed of neural responses to large objects.
Short Article: Syntax and Serial Recall: How Language Supports Short-Term Memory for Order
Authors: Perham Nick , Marsh John E. , Jones Dylan M.
Published: January 2009

The extent to which familiar syntax supports short-term serial recall of visually presented six-item sequences was shown by the superior recall of lists in which item pairs appeared in the order of “adjective–noun” (items 1–2, 3–4, 5–6)—congruent with English syntax—compared to when the order of items within pairs was reversed. The findings complement other evidence suggesting that short-term memory is an assemblage of language processing and production processes more than it is a bespoke short-term memory storage system.
Roles of BLOC-1 and Adaptor Protein-3 Complexes in Cargo Sorting to Synaptic Vesicles
Authors: Newell-Litwa Karen , Salazar Gloria , Smith Yoland , Faundez Victor
Published: January 2009

Neuronal lysosomes and their biogenesis mechanisms are primarily thought to clear metabolites and proteins whose abnormal accumulation leads to neurodegenerative disease pathology. However, it remains unknown whether lysosomal sorting mechanisms regulate the levels of membrane proteins within synaptic vesicles. Using high-resolution deconvolution microscopy, we identified early endosomal compartments where both selected synaptic vesicle and lysosomal membrane proteins coexist with the adaptor protein complex 3 (AP-3) in neuronal cells. From these early endosomes, both synaptic vesicle membrane proteins and characteristic AP-3 lysosomal cargoes can be similarly sorted to brain synaptic vesicles and PC12 synaptic-like microvesicles. Mouse knockouts for two Hermansky–Pudlak complexes involved in lysosomal biogenesis from early endosomes, the ubiquitous isoform of AP-3 (Ap3b1−/−) and muted, defective in the biogenesis of lysosome-related organelles complex 1 (BLOC-1), increased the content of characteristic synaptic vesicle proteins and known AP-3 lysosomal proteins in isolated synaptic vesicle fractions. These phenotypes contrast with those of the mouse knockout for the neuronal AP-3 isoform involved in synaptic vesicle biogenesis (Ap3b2−/−), in which the content of select proteins was reduced in synaptic vesicles. Our results demonstrate that lysosomal and lysosome-related organelle biogenesis mechanisms regulate steady-state synaptic vesicle protein composition from shared early endosomes.
Psychological Treatments for Pediatric Functional Gastrointestinal Disorders
Authors: Brent Meredith , Lobato Debra , LeLeiko Neal
Published: January 2009

Our objective was to systematically review and evaluate behavioral and psychological treatments applied to pediatric functional gastrointestinal disorders. Electronic searches were conducted in bibliographic databases including PubMed, PsychInfo, and Medline. Psychological and behavioral interventions were classified into the following 5 primary treatment modalities: psychoeducation, behavior therapy/contingency management, relaxation‐based therapies (including biofeedback and hypnotherapy), and cognitive‐behavioral therapy (including cognitive‐behavioral family therapy). There was a wide variation in the quality and quantity of studies within each treatment category. Effective interventions generally involved multiple therapeutic components and included elements of both individual and family treatment. Psychological interventions that combine psychoeducation, relaxation‐based therapies, and cognitive‐behavioral therapy appear superior to standard care (reassurance or dietary manipulation) in the elimination of pain and reduction in functional disability. Although many psychological treatments demonstrated evidence of positive effects, few well‐designed randomized controlled trials of psychological treatments for functional gastrointestinal disorders exist. More work is needed to determine the most potent, essential elements of psychological treatments alone or in combination with standard medical intervention, and to establish their applicability with diverse populations. Clinical and research implications are discussed.
Wilson Disease in Children: Analysis of 57 Cases
Authors: Manolaki Nina , Nikolopoulou Georgia , Daikos George L , Panagiotakaki Eleni , Tzetis Maria , Roma Eleftheria , Kanavakis Emmanouel , Syriopoulou Vassiliki P
Published: January 2009

Objectives:

Wilson disease (WD) has a wide spectrum of clinical manifestations. Affected children may be entirely asymptomatic and the diagnosis problematic. Herein we present the clinical and laboratory characteristics of 57 children with WD and point out the diagnostic difficulties in a pediatric population.

Patients and Methods:

Clinical and laboratory data were collected from 57 consecutive children with WD. Evaluation included detailed physical examination, conventional laboratory testing, genetic analysis, and liver biopsy.

Results:

The mean age at diagnosis was 9.27 ± 3.62 years (range 4 months–18 years). Twenty patients were symptomatic, 19 were referred because of abnormal liver function test results and/or hepatomegaly, and 18 received their diagnoses after family screening. Twenty‐two patients had both Kayser‐Fleischer ring and decreased serum ceruloplasmin levels, 13 had urinary copper excretion after penicillamine challenge >1600 μg/24 hours, and 3 had liver copper content >250 μg/g dry weight. Of the remaining 19 patients, 17 had both low serum ceruloplasmin ≤20 mg/dL and increased urinary copper excretion, >75 μg/24 hours before, or >1000 μg/24 hours after penicillamine challenge. In 2 patients with equivocal cases who had serum ceruloplasmin 26 mg/dL, the diagnosis was confirmed by genetic analysis. No correlation was found between specific mutations and the disease phenotypic expression. Chelating therapy was well tolerated, and the outcome was satisfactory.

Conclusions:

WD in children may be obscure and requires extensive investigation to establish the diagnosis. Genetic analysis is needed in equivocal cases.
British Paediatric Surveillance Unit Study of Biliary Atresia: Outcome at 13 Years
Authors: McKiernan PJ , Baker Alastair J , Lloyd Carla , Mieli‐Vergani Giorgina , Kelly Deirdre A
Published: January 2009

Background:

Little information is available on contemporary, prospectively collected data on the long‐term outcome of national cohorts of children with biliary atresia.

Objective:

This study aimed to describe the current outcome of a national cohort of children with biliary atresia.

Patients and Methods:

All 93 cases of biliary atresia in the United Kingdom and Ireland diagnosed between March 1993 and February 1995 were followed up prospectively.

Results:

A total of 91 children underwent Kasai portoenterostomy in 15 individual centres. Only 2 centres treated more than 5 children annually. Median age at last follow‐up was 12 years (range 0.25–14). Fifteen children (16%) have died: 10 after unsuccessful portoenterostomy, 1 of sepsis after successful portoenterostomy, and 4 after liver transplantation. Forty‐two (45%) underwent liver transplantation at a median age of 1 year (range 0.5–9), with 90% survival. All 41 children with failed portoenterostomy (and 2 without portoenterostomy) died or underwent liver transplantation at a median age of 0.8 years (range 0.25–6.5). When the portoenterostomy was successful, 40 of 50 patients (80%) are alive without liver transplantation. The 13‐year actuarial survival without liver transplantation is 43.8% overall and is better in children treated at centres that treat more than 5 cases yearly (54% vs 27.3%, P = 0.005).

Conclusions:

If the portoenterostomy is successful, then few children with biliary atresia will need transplantation before adolescence. Children with biliary atresia should be treated in experienced centres to maximize the chance of successful surgery.
Are sex-biased genes more dispensable?
Authors: Mank Judith E. , Ellegren Hans
Published: January 2009

Many genes show different expression levels in males and females, and these form the basis of sexually dimorphic phenotypes. Sex-biased genes experience accelerated rates of protein evolution, which has been attributed to sexual selection. However, it is possible that the increased rates of molecular evolution, and more importantly the sex-biased gene expression pattern itself, are due to decreased selective constraint. This notion may explain many of the patterns associated with sex-biased gene expression, and changes how we should view the role of natural and sexual selection in relation to these genes.
D-cycloserine potentiates the reconsolidation of cocaine-associated memories
Authors: Lee Jonathan L.C. , Gardner Richard J. , Butler Victoria J. , Everitt Barry J.
Published: January 2009

Conditioned cue-induced relapse to drug seeking is a major challenge to the treatment of drug addiction. It has been proposed that D-cycloserine might be useful in the prevention of relapse by reducing the conditioned reinforcing properties of drug-associated stimuli through facilitation of extinction. Here we show that intrabasolateral amygdala infusions of D-cycloserine in fact potentiate the reconsolidation of stimulus–cocaine memories to increase cue-induced relapse to drug seeking in rats with an extensive drug self-administration history. This elevation of cocaine seeking was correlated with an increase in the expression of the reconsolidation-associated gene zif268.
Self‐assembly of sapovirus recombinant virus‐like particles from polyprotein in mammalian cells
Authors: Oka Tomoichiro , Yamamoto Mami , Miyashita Kana , Ogawa Satoko , Katayama Kazuhiko , Wakita Takaji , Takeda Naokazu
Published: January 2009

The SaV genome is a positive‐sense, non‐segmented single‐strand RNA molecule of approximately 7.5 kb that is polyadenylated at its 3′ terminus. The major capsid (VP1) of SaV is thought to be produced as the ORF1 polyprotein followed by cleavage, or translation from subgenomic RNA (3′‐coterminal with the virus genome), or both. We have recently reported the formation of SaV VLP from subgenomic‐like RNA in mammalian cells. In the present study, we demonstrated that the VP1 cleaved from a part of ORF1 polyprotein self‐assembled into VLP in mammalian cells when a transient expression system using a recombinant vaccinia virus encoding T7 RNA polymerase was used.
Annual growth ofCassiope tetragonaas a proxy for Arctic climate: developing correlative and experimental transfer functions to reconstruct past summer temperature on a millennial time scale
Authors: ROZEMA JELTE , WEIJERS STEF , BROEKMAN ROB , BLOKKER PETER , BUIZER BERT , WERLEMAN CHANTAL , EL YAQINE HASSAN , HOOGEDOORN HANNEKE , FUERTES MIGUEL MAYORAL , COOPER ELISABETH
Published: January 2009

Annual growth of the polar evergreen shrubCassiope tetragonaon Svalbard was evaluated as a proxy for Arctic summer temperatures. Transfer functions were derived from temperature‐growth correlations of shoots and from a temperature‐growth response, obtained from experimental warming using open top chambers (OTC) in high Arctic tundra vegetation at Isdammen approximately 1.5 km southeast of Longyearbyen, Svalbard (78°N, 15 E) and in Longyeardalen, 3 km west of Isdammen from 2004 to 2006. Air temperatures, monitored throughout the summer months, were 1.3 °C higher inside the OTCs than in the control plots. Annual stem growth was measured by tagging stems and leaves, and in the lab with shoots harvested from OTCs and control plots. Annual growth parameters assessed were leaf production, sum of length and weight of individual leaves, and stem length increment derived from leaf scar distances and the distances between wintermarksepta in the stem. Wintermarksepta are formed at the end of the summer growth period when the pith is narrowing and consist of dense and dark tissue (Fig. 1b). The variation of annual growth in a 34‐year site chronology (based onCassiopeshoots from the surroundings of the OTCs and control plots) correlated strongly with the mean summer temperature on Svalbard. The number of leaf pairs, leaf length and stem length also increased in the OTC warmed plots in the second and third year of warming. Transfer functions were derived from the temperature‐annual growth correlations from a single shoot from Longyeardalen, from the cross‐dated Isdammen site chronology and from the growth response to experimental warming. Based on leaf scar distances and distances between wintermarksepta of well‐preserved subfossil shoots in arctic tundra soil, annual stem length increase was assessed for the layers of a soil core collected at the Isdammen site. Based on the derived transfer functions summer temperature of the period relating to the 15 cm deep tundra soil core layer, radiocarbon dated at 4230±40 bp, may have been 3.0 °C lower than the present‐day 6.2 °C value. These results indicate that the transfer functions can be used to reconstruct past temperatures, beyond the time range of instrumental temperature and ice core records of Svalbard.

 (a) Morphology of shoot ofCassiope tetragonacollected May 26, 2007, Longyeardalen. Removal of the front row of leaves shows four leaf pairs of the 2006 summer, the leaf primordium for the 2007 growing season and the stem length increase summer 2006. (b) Wintermarksepta, darker colored than the pith tissue, indicating the winterperiod in a longitudinal section of an air‐dried shoot collected August 26, 2006, Longyeardalen.

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Past century changes in Araucaria angustifolia (Bertol.) Kuntze water use efficiency and growth in forest and grassland ecosystems of southern Brazil: implications for forest expansion
Authors: SILVA LUCAS C. R. , ANAND MADHUR , OLIVEIRA JULIANO M. , PILLAR VALÉRIO D.
Published: January 2009

Araucaria angustifolia (Bertol.) Kuntze is an indigenous conifer tree restricted to the southern region of South America that plays a key role in the dynamics of regional ecosystems where forest expansion over grasslands has been observed. Here, we evaluate the changes in intrinsic water use efficiency (iWUE) and basal area increment (BAI) of this species in response to atmospheric CO2, temperature and precipitation over the last century. Our investigation is based on tree‐rings taken from trees located in forest and grassland sites in southern Brazil. Differences in carbon isotopic composition (δ13C), 13CO2 discrimination (Δ13C) and intracellular carbon concentration (Ci) are also reported. Our results indicate an age effect on Δ13C in forest trees during the first decades of growth. This age effect is not linked to an initial BAI suppression, suggesting the previous existence of nonforested vegetation in the forest sites. After maturity all trees show similar temporal trends in carbon isotope‐derived variables and increasing iWUE, however, absolute values are significantly different between forest and grassland sites. The iWUE is higher in forest trees, indicating greater water competition or nutritional availability, relative to grassland, or both. BAI is also higher in forest trees, but it is not linked with iWUE or atmospheric CO2. Nevertheless, in both forest and grassland sites A. angustifolia has had growth limitations corresponding to low precipitation and high temperatures observed in the 1940s.
The origins and diversification of C4 grasses and savanna‐adapted ungulates
Authors: BOUCHENAK‐KHELLADI YANIS , ANTHONY VERBOOM G. , HODKINSON TREVOR R. , SALAMIN NICOLAS , FRANCOIS OLIVIER , NÍ CHONGHAILE GRAINNE , SAVOLAINEN VINCENT
Published: January 2009

C4 grasses constitute the main component of savannas and are pervasive in other dry tropical ecosystems where they serve as the main diet for grazing animals. Among potential factors driving C4 evolution of grasses, the interaction between grasses and grazers has not been investigated. To evaluate if increased grazing pressure may have selected for higher leaf silica production as the grasses diverged, we reconstructed the phylogeny of all 800 genera of the grass family with both molecular (combined multiplastid DNA regions) and morphological characters. Using molecular clocks, we also calculated the age and number of origins of C4 clades and found that shifts from C3 to C4 photosynthesis occurred at least 12 times starting 30.9 million years ago and found evidence that the most severe drop in atmospheric carbon dioxide in the late Oligocene (between 33 and 30 million years ago) matches the first origin of C4 photosynthesis in Chloridoideae. By combining fossil and phylogenetic data for ungulates and implementing a randomization procedure, our results showed that the appearance of C4 grass clades and ungulate adaptations to C4‐dominated habitats match significantly in time. An increase of leaf epidermal density of silica bodies was found to correspond to postulated shifts in diversification rates in the late Miocene [24 significant shifts in diversification (P<0.05) were detected between 23 and 3.7 million years ago]. For aristidoid and chloridoid grasses, increased grazing pressure may have selected for a higher leaf epidermal silica production in the late Miocene.
Soil drying and nitrogen availability modulate carbon and water exchange over a range of annual precipitation totals and grassland vegetation types
Authors: St. CLAIR SAMUEL B. , SUDDERTH ERIKA A. , FISCHER MARC L. , TORN MARGARET S. , STUART STEPHANIE A. , SALVE ROHIT , EGGETT DENNIS L. , ACKERLY DAVID D.
Published: January 2009

Increased intensity in precipitation events and longer periods of water deficit are predicted as a general trend under future climate scenarios with potentially large effects on terrestrial ecosystem function. The primary objective of this study was to understand how variation in the intensity of precipitation inputs followed by intermittent soil drying events influence leaf and ecosystem carbon dioxide (CO2) and water exchange in a California annual grassland mesocosm experiment. We further examined how nitrogen (N) availability, and differences in plant community composition (grass‐forb combinations) affected gas exchange responses to the precipitation treatments. Net ecosystem CO2 exchange (NEE) and evapotranspiration (ET) increased significantly with greater precipitation and were positively correlated with soil moisture. A repeated 10‐day soil drying period, following 11 days of watering, strongly depressed NEE over a range of annual precipitation totals (297, 657 and 987 mm), and plant community types. Ecosystem dark respiration (Re) and leaf level photosynthesis (Amax) showed greater sensitivity to periods of soil drying in the low precipitation plots (297 mm). N additions significantly increased NEE and Re, particularly as water availability was increased. Across the range of precipitation totals and plant community types, intermittent periods of soil moisture deficit and native soil N availability constrained leaf and ecosystem level CO2 exchange, while the influence on water vapor exchange was less pronounced.
Platelet von Willebrand factor determination does not improve the diagnosis of patients with suspected Type 1 von Willebrand disease
Authors: SHIHONG I. , MORRIS D. , KONKLE B. A.
Published: January 2009

Summary.  Establishing a laboratory diagnosis of a bleeding disorder can be challenging for some patients who present with mucocutaneous bleeding symptoms. A common clinical scenario is an older patient with a prior diagnosis of von Willebrand disease (VWD) or a family history of VWD, who now has von Willebrand factor (VWF) values repeatedly within the normal range. Plasma VWF antigen levels have been shown to increase with age. Whether platelet VWF increases with age is unknown. We hypothesized that platelet VWF does not increase with age and low platelet VWF levels, despite normal plasma levels, could be a reason for continued bleeding symptoms in some patients. Therefore, we compared the platelet and plasma VWF antigen and activity as well as the platelet function analyzer (PFA)‐100® closure times in 35 patients with a history of mucocutaneous bleeding symptoms and consistently normal levels of VWF antigen and activity, despite a prior history of a VWD diagnosis and/or a positive family history of VWD. Overall in our patients (bleeders), the platelet VWF values correlated with the plasma values and only three patients had reduced platelet VWF. In the bleeding group, the PFA‐100® results showed an inverse correlation with plasma and platelet values, which was stronger for the plasma values. Therefore, platelet VWF determination was not helpful in the diagnosis of suspected mild type 1 VWD.
Registry of inherited coagulopathies in Brazil: first report
Authors: REZENDE S. M. , PINHEIRO K. , CARAM C. , GENOVEZ G. , BARCA D.
Published: January 2009

Summary.  Inherited coagulopathies are bleeding disorders, which require treatment for life. Keeping an updated registry on these diseases is crucial for planning care, documenting prevalence of diseases and evaluating effectiveness of resources. We have analysed data from 26 treatment centres on coagulopathies in Brazil. Information included socio‐demographic data, diagnosis of coagulopathies, severity of haemophilias A and B, presence and quantification of inhibitors in haemophilia, type of von Willebrand disease (VWD) and infection status for viral diseases. On 1 July 2007, there were 10 982 patients with inherited coagulopathies in Brazil, of which 6881 (62.7%) corresponded to haemophilia A, 1291 (11.7%) to haemophilia B, 2333 (21.2%) to VWD, 258 (2.4%) to other coagulopathies and 219 (2.0%) to undiagnosed bleeding disorders. Haemophilia A and B inhibitors were present in 9.9% and 1.9% of the patients, respectively. Human immunodeficiency virus infection was present is 6.5%, 4.8% and 1% of patients with haemophilia A, B and VWD, respectively. Hepatitis C virus infection was present in 34.9%, 29.7% and 12% of patients with haemophilia A, B and VWD, respectively. Infection by hepatitis B and human T‐cell leukemia‐lymphoma virus was also reported. This is the first report on the registry of patients with inherited coagulopathies in Brazil, supposed to be the third largest population of patients with haemophilia.
Factor VII deficiency: clinical manifestation of 717 subjects from Europe and Latin America with mutations in the factor 7 gene
Authors: HERRMANN F. H. , WULFF K. , AUERSWALD G. , SCHULMAN S. , ASTERMARK J. , BATOROVA A. , KREUZ W. , POLLMANN H. , RUIZ‐SAEZ A. , DE BOSCH N. , SALAZAR‐SANCHEZ L. ,   FOR THE GREIFSWALD FACTOR FVII DEFICIENCY STUDY GROUP
Published: January 2009

Summary.  The congenital FVII deficiency (FVIID) is a rare haemorrhagic disorder with an autosomal recessive pattern of inheritance. Data on phenotype and the genotype from 717 subjects in Central Europe (six countries), Latin America (Costa Rica, Venezuela) and United States, enrolled in the Greifswald Registry of FVII Deficiency were analysed. We detected 131 different mutations in 73 homozygous, 145 compound heterozygous and 499 heterozygous subjects. Regional differences were observed in the mutation pattern and the clinical profile of the evaluated patients. Seventy‐one per cent of homozygous and 50% of compound heterozygous subjects were symptomatic. The clinical manifestations of the homozygous subjects were characterized by intracranial haemorrhage (2%), gastrointestinal bleeding (17%), haemarthrosis (13%), epistaxis (58%), gum bleeding (38%), easy bruising (37%), haematoma (15%), haematuria (10%) and menorrhagia (19 of 26 females, 73%). The clinical variability and genotype–phenotype correlation was evaluated in the homozygous subjects. The pattern of bleeding symptoms among compound heterozygous patients was severe and similar to that of the homozygous patients. The large‐scale analysis of 499 heterozygous subjects shows that 93 (19%) presented with spontaneous bleeding symptoms such as haemarthrosis (4%), epistaxis (54%), gum bleeding (14%), easy bruising (38%), haematoma (23%), haematuria (5%) and menorrhagia (19 of 45 females; 42%). The severe haemorrhages – intracranial and gastrointestinal – were not reported in heterozygous subjects. The clinical variability and the regional differences in the mutation pattern are discussed regarding care and treatment.
The use of technology in cancer care: applying Foucault’s ideas to explore the changing dynamics of power in health care
Authors: Forbat Liz , Maguire Roma , McCann Lisa , Illingworth Nicola , Kearney Nora
Published: January 2009

Title.  The use of technology in cancer care: applying Foucault’s ideas to explore the changing dynamics of power in health care.

Aim.  This study is a report to identify the utility of a hand‐held side‐effect monitoring system for people receiving chemotherapy in the home care setting.

Background.  Increasingly, health care is being provided in people’s own homes and communities rather than in hospitals. This has driven the development of technologies which support patients in the home environment. The meaning of such technologies can be explored from a Foucauldian perspective to shed light on how they enable new forms of medical surveillance.

Method.  An intervention study was performed in 2006 using new technologies for people receiving chemotherapy. Questionnaires were completed by 56 people affected by cancer who used the new technology; 12 of these people were then interviewed. Secondary analysis of the interview data is presented in this paper, drawing on Foucault’s writing about surveillance and power in medical settings.

Findings.  The interview transcripts contain numerous examples of people affected by cancer reflecting on issues such as power and surveillance in cancer care. While these terms are ordinarily considered to reflect negative elements of care, they were used by participants in an empowering manner.

Conclusion.  Theoretical insights can help nurses to think critically about the advances of technology. In particular, there are implications for how nurses consider the relationship of technology to patients and for power dynamics in healthcare relationships. We suggest that there is a need to problematize and celebrate the growth of technologically‐driven health surveillance.