bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Processing Speed in Children With Low Reading Ability and in Children and Adults With Typical Reading Ability: Exploratory Factor Analytic Models
Authors: Peter Beate , Matsushita Mark , Raskind Wendy H.
Published: November 2010

Purpose

To investigate processing speed as a latent dimension in children with dyslexia and children and adults with typical reading skills.

Method

Exploratory factor analysis (FA) was based on a sample of multigenerational families, each ascertained through a child with dyslexia. Eleven measures—6 of them timed—represented verbal and nonverbal processes, alphabet writing, and motor sequencing in the hand and oral motor system. FA was conducted in 4 cohorts (all children, a subset of children with low reading scores, a subset of children with typical reading scores, and adults with typical reading scores; totalN= 829).

Results

Processing speed formed the first factor in all cohorts. Both measures of motor sequencing speed loaded on the speed factor with the other timed variables. Children with poor reading scores showed lower speed factor scores than did typical peers. The speed factor was negatively correlated with age in the adults.

Conclusions

The speed dimension was observed independently of participant cohort, gender, and reading ability. Results are consistent with a unified theory of processing speed as a quadratic function of age in typical development and with slowed processing in poor readers.
Hot phonon-plasmon modes in GaN
Authors: Dyson A. , Ridley B. K.
Published: November 2010

Hot phonon effects are of interest for heterostructure field effect transistors where heat dissipation depends on the lifetime of the longitudinal optical mode. Previous treatments have ignored the coupling of plasmon and phonons. Here, a bulk-phonon model is used to examine the effects of hot phonon-plasmon coupled modes based on the random-phase Lindhard dielectric function with nondegenerate statistics and a nonparabolic conduction band. Comparison of the results concerning power dissipation and drift velocity with those for bare phonons assuming a constant phonon lifetime indicate no striking differences. The phonon lifetime is known to exhibit a temperature and electron density dependence in GaN. Incorporating the observed dependence of lifetime on electron density profoundly affects the hot phonon effect. We find that the drift velocity, as expected, becomes limited by the production of hot phonons at high electric fields as the electron density is increased but this reduction in velocity is ameliorated by the concomitant reduction in the phonon lifetime with increasing density. The result is that hot phonon effects become insensitive to electron density at high fields.
Formation of undulated lamellar structure from ABC block terpolymer blends with different chain lengths
Authors: Matsushita Yushu , Suzuki Jiro , Izumi Yuuki , Matsuoka Kohei , Takahashi Shuji , Aoyama Yoshitaka , Mihira Tomohiro , Takano Atsushi
Published: November 2010

The effect of molecular weight distribution of ABC linear terpolymers on the formation of periodic structures was investigated. Three poly(isoprene-b-styrene-b-2-vinylpridine) triblockterpolymers with molecular weights of 26k, 96k, and 150k were blended variously. Three-phase, four-layer lamellar structures were observed when polydispersity index (PDI) was low, but it has been found that simple lamellar structure with flat surface transforms into an undulated lamellar one, where two interfaces, i.e., I/S and S/P, are both undulated, and they are synchronizing each other if PDI exceeds the critical value. This new structure could be formed due to the periodic and “weak” localization of three chains along the domain interfaces, which produces periodic surfaces with nonconstant mean curvatures. With further increase of PDI, the blend macroscopically phase-separated into different microphase-separated structures.
IR spectroscopy on isolated Con(alcohol)m cluster anions (n=1–4,m=1–3): Structures and spin states
Authors: Bialach P. M. , Funk A. , Weiler M. , Gerhards M.
Published: November 2010

Isolated cobalt-alcohol cluster anions containing n=1–4 cobalt and m=1–3 alcohol molecules (alcohol=methanol, ethanol, propanol) are produced in a supersonic beam by using a laser ablation source. By applying IR photodissociation spectroscopy vibrational spectra in the OH stretching region are obtained. Several structures in different spin states are discussed for the (n,m) clusters. In comparison with density functional theory calculations applied to both the Co/alcohol clusters and the naked Co cluster anions, an unambiguous structural assignment is achieved. It turns out that structures are preferred with a maximum number of hydrogen bonds between the OH groups and the Co⋯Co units. These hydrogen bonds are typical for anionic species leading to an activation of the OH groups which is indicated by large red-shifts of the OH stretching frequencies compared to the naked alcohols. For each (n,m) cluster, the frequency shifts systematically with respect to the different alcohols, but the type of structure is identical for all alcohol ligands. The application of IR spectroscopy turns out to be an ideal tool not only as a probe for structures but also for spin states which significantly influence the predicted OH stretching frequencies.
Quantum computing applied to calculations of molecular energies: CH2 benchmark
Authors: Veis Libor , Pittner Jiří
Published: November 2010

Quantum computers are appealing for their ability to solve some tasks much faster than their classical counterparts. It was shown in [Aspuru-Guzik et al., Science 309, 1704 (2005)] that they, if available, would be able to perform the full configuration interaction (FCI) energy calculations with a polynomial scaling. This is in contrast to conventional computers where FCI scales exponentially. We have developed a code for simulation of quantum computers and implemented our version of the quantum FCI algorithm. We provide a detailed description of this algorithm and the results of the assessment of its performance on the four lowest lying electronic states of CH2 molecule. This molecule was chosen as a benchmark, since its two lowest lying A11 states exhibit a multireference character at the equilibrium geometry. It has been shown that with a suitably chosen initial state of the quantum register, one is able to achieve the probability amplification regime of the iterative phase estimation algorithm even in this case.
A geometric interpretation of prolongation by means of connections
Authors: Bracken Paul
Published: November 2010

A geometric interpretation of prolongation can be formulated by using the theory of connections. A fiber bundle can be established which is composed of a base manifold and variables which span a prolongation space. A particular connection is introduced in terms of these coordinates. This provides a very different way of viewing the technique and for introducing prolongation algebras as well as generating integrable equations in a novel way.
Illumination effect on electrical characteristics of organic-based Schottky barrier diodes
Authors: Uslu Habibe , Altındal Şemsettin , Dökme İlbilge
Published: November 2010

The forward and reverse bias capacitance–voltage (C−V) and conductance–voltage (G/ω−V) characteristics of Au/polyvinyl alcohol (Co, Zn-doped)/n-Si Schottky barrier diodes have been investigated depending on illumination intensity at room temperature and 1 MHz. These experimental C−V and G/ω−V characteristics show fairly large illumination dispersion especially in the weak inversion and depletion regions and they increase with the increasing illumination intensity because of the illumination induced interface states and electron-hole pair. The C−V plots show that peaks are the results of the particular distribution density of the interface states (Nss), interfacial polymer layer, and series resistance (Rs) of device. The magnitude of the peaks increases with the increasing illumination intensity and their positions shift from the high forward bias voltage to low forward bias voltages. The C−2−V plots give a straight line in a wide bias voltage region for each illumination intensity. The variation in doping concentration (ND), depletion layer width (WD), and barrier height [ΦB(C−V)] were obtained from these C−2−V plots. In addition, voltage dependent density distribution profile of Nss was obtained from both low-high capacitance (CLF−CHF) and Hill–Coleman methods. It is observed that there is a good agreement between the results obtained by these methods. In addition, voltage dependent Rs profile was obtained from C−V and G/ω−V data by using Nicollian and Brews method.
Effect of progressive substitution of Bi3+ by La3+ on the structural, magnetic, and transport properties of Bi0.6Ca0.4MnO3
Authors: Zhang R. R. , Kuang G. L. , Yin L. H. , Sun Y. P.
Published: November 2010

Structural, magnetic, and electronic transport properties of Bi0.6−xLaxCa0.4MnO3 (0≤x≤0.6) manganites have been studied systematically. The parent compound exhibits robust charge ordered antiferrromagnetic (COAFM) phase with TCO∼293 K and AFM Néel temperature TN∼149 K. The sample with x=0.1 show a M(T) curve of “arch bridge” form between 142 and 253 K, which is attributed to the AFM peak embedded in the broad transition of the CO. For the middle doping samples (0.2≤x≤0.4), although the CO peaks disappear as a result of the suppression of the long range CO state, AFM superexchange coupling has been strengthened with the increasing of La doping level. The Bi0.1La0.5Ca0.4MnO3 sample shows interesting phenomena such as magnetization steps and magnetic memory effect. The resistivity of the samples exhibits insulating behavior in our measured temperature range for x≤0.4. While both x=0.5 and x=0.6 compounds exhibit metal–insulator transition. Furthermore, large low field magnetoresistance (MR) and hysteresis appears only in the MR(H) curve of x=0.5 sample. These results are discussed in terms of the charge localization caused by the lattice distortion due to the character of the 6s2 lone pair of Bi3+ ions.
Investigations of growth kinetics of pulsed laser deposition of tin oxide films by isotope tracer technique
Authors: Zhen Yuhua , Ohsawa Takeo , Adachi Yutaka , Sakaguchi Isao , Li Baoe , Li Jianyong , Matsuoka Ryota , Nishimura Toshiyuki , Matsumoto Kenji , Haneda Hajime , Ohashi Naoki
Published: November 2010

Tin dioxide (SnO2) is an important semiconductor oxide that exhibits many interesting optoelectronic properties. Furthermore, the physical and chemical deposition of single crystalline films from vapor phase is the most promising way for growing high-quality SnO2 films. In this paper, the growth kinetics of the pulsed laser deposition (PLD) of SnO2 films has been elucidated by varying the growth conditions and using the isotope tracer technique. We have experimentally demonstrated that relatively low oxygen partial pressures and high growth temperatures cause the re-evaporation of Sn from the surface of a growing film; these conditions are essential to achieve layer-by-layer growth of SnO2 by PLD. Further, when a TiO2 substrate with an atomically flat surface was used, the SnO2 film had an atomically flat surface.
Benefits and concerns of a closed nuclear fuel cycle
Authors: Widder Sarah
Published: November 2010

Nuclear power can play an important role in our energy future, helping to meet increasing electricity demand while at the same time decreasing carbon dioxide emissions. However, the nuclear fuel cycle in the United States today is unsustainable. The 1982 Nuclear Waste Policy Act establishes the U.S. Department of Energy as responsible for disposing of spent nuclear fuel (SNF) generated by commercial nuclear power plants operating in a “once-through” fuel cycle in a deep geologic repository located at Yucca Mountain, NV. However, unyielding political opposition to the Yucca Mountain site has hindered the commissioning process to the extent that the current administration has recently declared the site unsuitable. In light of this, the DOE is exploring other options, including closing the fuel cycle through reprocessing and recycling of spent nuclear fuel. The possibility of closing the fuel cycle is receiving special attention because of its ability to minimize the final high level waste package by separating and isolating the most long-lived components, as well as recovering additional energy value from the original fuel. Reprocessing and recycling of SNF can decrease the volume of waste stored by a factor of 4 and reduce the timeframe of storage from hundreds of thousands of years to thousands of years. Reprocessing and recycling technologies are, however, still very controversial because of the increased cost and proliferation risk reprocessing can present. Estimates of increases in the levelized cost of electricity with reprocessing range from about 10% to 50% due to large uncertainties in the financing, construction, and licensing of a new plant. Ultimately, the U.S. will need to compare each of these fuel cycle options with respect to sustainability, proliferation risk, commercial viability, waste management, and energy security to define the future of nuclear power.
Structural and optical properties of dilute InAsN grown by molecular beam epitaxy
Authors: Ibáñez J. , Oliva R. , De la Mare M. , Schmidbauer M. , Hernández S. , Pellegrino P. , Scurr D. J. , Cuscó R. , Artús L. , Shafi M. , Mari R. H. , Henini M. , Zhuang Q. , Godenir A. , Krier A.
Published: November 2010

We perform a structural and optical characterization of InAs1−xNx epilayers grown by molecular beam epitaxy on InAs substrates (x≲2.2%). High-resolution x-ray diffraction (HRXRD) is used to obtain information about the crystal quality and the strain state of the samples and to determine the N content of the films. The composition of two of the samples investigated is also obtained with time-of-flight secondary ion mass spectroscopy (ToF-SIMS) measurements. The combined analysis of the HRXRD and ToF-SIMS data suggests that the lattice parameter of InAsN might significantly deviate from Vegard’s law. Raman scattering and far-infrared reflectivity measurements have been carried out to investigate the incorporation of N into the InAsN alloy. N-related local vibrational modes are detected in the samples with higher N content. The origin of the observed features is discussed. We study the compositional dependence of the room-temperature band gap energy of the InAsN alloy. For this purpose, photoluminescence and optical absorption measurements are presented. The results are analyzed in terms of the band-anticrossing (BAC) model. We find that the room-temperature coupling parameter for InAsN within the BAC model is CNM=2.0±0.1 eV.
Quenching of NO(A Σ2+) state in a nonequilibrium air plasma
Authors: Studer D. , Boubert P. , Vervisch P.
Published: November 2010

An unexpectedly high quenching rate (2×109 s−1) of NO(A Σ2+) state has been measured during laser-induced fluorescence measurements of NO densities carried out using a broadband KrF laser in an inductively coupled nonequilibrium air plasma at moderate pressure (38 hPa) and translational temperatures (2500–3000 K). Many assumptions may be made to explain such a high quenching rate but most fail. The quenching species is identified as being produced during the laser pulse but remains unknown in spite of thorough investigations.
New Products
Authors: Mandelis Andreas
Published: November 2010

In order to supplement manufacturers’ information this Department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
Formation of periodic nanotube array through the Kirkendall effect in epitaxial heterostructures
Authors: Taylor P. J. , Sarney W. , Swaminathan V.
Published: November 2010

The spontaneous formation of hollow nanotubes at the heteroepitaxial interface between near lattice-matched PbSe and ZnTe is reported. Mass-spectroscopy measurements show that the rapid diffusion of zinc into PbSe, and reduced diffusion of Pb outward, governs the formation of the nanotubes by a Kirkendall vacancy-condensation mechanism. High-resolution electron microscopy shows that the diameter of the tubes ranges from 10 to 100 nm, and the spacing between neighboring nanotubes is consistent with the equilibrium spacing of misfit dislocations, suggesting that the strain field of misfit dislocations acts as the nucleation site of the nanotubes.
Origin of high solubility of silicon in La2O3: A first-principles study
Authors: Umezawa Naoto , Shiraishi Kenji
Published: November 2010

The solubility of silicon in high-permittivity (high-κ) oxides significantly affects the performance of field-effect transistors. Our comparative study of silicon impurities in La2O3 and HfO2 reveals that the stability of silicon at substitutional sites strongly depends on its coordination number. When substituted for lanthanum, a silicon atom fits comfortably in La2O3, thanks to the formation of a SiO4 tetrahedral structure. In addition, the substitutional silicon acts as a donor impurity in La2O3, increasing oxygen content in the oxide. This contributes to absorbing silicon and oxygen from the interface region, leading to the formation of lanthanum silicate at the La2O3/silicon interface.
Photon energy threshold for filling boron induced charge traps in SiO2 near the Si/SiO2 interface using second harmonic generation
Authors: Park Heungman , Xu Ying , Varga Kalman , Qi Jingbo , Feldman Leonard C. , Lüpke Gunter , Tolk Norman
Published: November 2010

We report the experimental determination of the threshold energy for filling the B+ induced charge traps in SiO2 near the Si/SiO2 interface, using a two-color pump-probe approach involving internal photoemission and second harmonic generation. The threshold photon energy for filling the B+ induced charge trap is 2.61 eV (λ=475 nm) for single photon excitation between the silicon valence band and the B+ trap energy level in SiO2.
Stress-induced current and luminescence modulations in an organic light-emitting device
Authors: Jiang Z. Y. , Cao X. A.
Published: November 2010

The responses of the electrical and optical characteristics of an organic light-emitting device (OLED) with fac-tris(2-phenylpyridinato-N, C2′) iridium (III) [Ir(ppy)3] doped in a polymer matrix to compressive stresses were studied. The OLED converted stresses as low as 6.8 kPa into measurable and reversible changes in both current density and electroluminescence (EL) intensity. The current showed a nearly linear characteristic response with sensitivity up to 105 μA/kPa, whereas EL decreased by three orders of magnitude at 100 kPa. The latter was attributed to increased nonradiative back energy transfer between Ir(ppy)3 and neighboring host molecules. It is expected that similar OLEDs built on large curved surfaces may directly image stress distributions at a high-resolution and sense touch on a par with a human finger.
The Rabelaisian Border
Authors: Kramsch Olivier Thomas
Published: November 2010

In 1930 the French historian Lucien Febvre and geographer Albert Demangeon were commissioned to coauthor a book on the Rhine. In preparation for this volume, and with war clouds gathering on the horizon, they took an upriver Rhineland journey into Europe's heart of darkness. Around this time, Febvre began taking notes for what would later become his magisterial study of François Rabelais. From the intellectual cross-fertilization of these apparently unrelated events this paper suggests Febvre inaugurates a political moment for European border studies, with important resonances for our day. This moment, derived from Febvre's analysis of the Rhine as a vast, integrating force in the modern period and his reading of Rabelais's own stubbornly persistent religiosity, suggests a method for border studies that takes into account the temporal specificity of borders in European history and trains attention on the everyday ‘mentalities’ of those inhabiting lived borders while foregrounding the problem of the Other as central to any proper understanding of the spatiality of borders. In thus posing the border as a geohistorical histoire-problème, Febvre reinjects the notion of possibility into border studies and makes of border space a properly political object of re-worlding. The paper then reviews a selection of canonical texts in border studies dating from the mid to late 1990s and invites a dialogue with the smiling figure of Rabelais.
Structural basis for substrate activation and regulation by cystathionine beta-synthase (CBS) domains in cystathionine β-synthase
Authors: Koutmos Markos , Kabil Omer , Smith Janet L. , Banerjee Ruma
Published: November 2010

The catalytic potential for H
2
S biogenesis and homocysteine clearance converge at the active site of cystathionine β-synthase (CBS), a pyridoxal phosphate-dependent enzyme. CBS catalyzes β-replacement reactions of either serine or cysteine by homocysteine to give cystathionine and water or H
2
S, respectively. In this study, high-resolution structures of the full-length enzyme from
Drosophila
in which a carbanion (1.70 Å) and an aminoacrylate intermediate (1.55 Å) have been captured are reported. Electrostatic stabilization of the zwitterionic carbanion intermediate is afforded by the close positioning of an active site lysine residue that is initially used for Schiff base formation in the internal aldimine and later as a general base. Additional stabilizing interactions between active site residues and the catalytic intermediates are observed. Furthermore, the structure of the regulatory “energy-sensing” CBS domains, named after this protein, suggests a mechanism for allosteric activation by
S
-adenosylmethionine.
Induction of cell death after localization to the host cell mitochondria by the Mycobacterium tuberculosis PE_PGRS33 protein
Authors: Cadieux Nathalie , Parra Marcela , Cohen Hannah , Maric Dragan , Morris Sheldon L. , Brennan Michael J.
Published: November 2010

PE_PGRS33 is the most studied member of the unique PE family of mycobacterial proteins. These proteins are composed of a PE domain (Pro–Glu motif), a linker region and a PGRS domain (polymorphic GC-rich-repetitive sequence). Previous studies have shown that PE_PGRS33 is surface-exposed, constitutively expressed during growth and infection, involved in creating antigenic diversity, and able to induce death in transfected or infected eukaryotic cells. In this study, we showed that PE_PGRS33 co-localizes to the mitochondria of transfected cells, a phenomenon dependent on the linker region and the PGRS domain, but not the PE domain. Using different genetic fusions and chimeras, we also demonstrated a direct correlation between localization to the host mitochondria and the induction of cell death. Finally, although all constructs localizing to the mitochondria did induce apoptosis, only the wild-type PE_PGRS33 with its own PE domain also induced primary necrosis, indicating a potentially important role for the PE domain. Considering the importance of primary necrosis inMycobacterium tuberculosisdissemination during natural infection, the PE_PGRS33 protein may play a crucial role in the pathogenesis of tuberculosis.
Degradation of fibrinogen and collagen by staphopains, cysteine proteases released from Staphylococcus aureus
Authors: Ohbayashi Takehisa , Irie Atsushi , Murakami Yoji , Nowak Magdalena , Potempa Jan , Nishimura Yasuharu , Shinohara Masanori , Imamura Takahisa
Published: November 2010

Staphylococcus aureusis the most frequently isolated pathogen in Gram-positive sepsis often complicated by a blood clotting disorder, and is the leading cause of infective endocarditis induced by bacterial destruction of endocardial tissues. The bacterium secretes cysteine proteases referred to as staphopain A (ScpA) and staphopain B (SspB). To investigate virulence activities of staphopains pertinent to clotting disorders and tissue destruction, we examined their effects on collagen, one of the major tissue components, and on plasma clotting. Both staphopains prolonged the partial thromboplastin time of plasma in a dose- and activity-dependent manner, with SspB being threefold more potent than ScpA. Staphopains also prolonged the thrombin time of both plasma and fibrinogen, indicating that these enzymes can cause impaired plasma clotting through fibrinogen degradation. Whereas SspB cleaved the fibrinogen Aα-chain at the C-terminal region very efficiently, ScpA degraded it rather slowly. This explains the superior ability of the former enzyme to impair fibrinogen clottability. Enzymically active staphopains, at concentrations as low as 10 nM, degraded collagen with comparable efficiency. These results show novel virulence activities of staphopains in degrading fibrinogen and collagen, and suggest an involvement of staphopains in the clotting impairment and tissue destruction caused by staphylococcal infection.
Structural and Metabolic Transitions of C4 Leaf Development and Differentiation Defined by Microscopy and Quantitative Proteomics in Maize
Authors: Majeran Wojciech , Friso Giulia , Ponnala Lalit , Connolly Brian , Huang Mingshu , Reidel Edwin , Zhang Cankui , Asakura Yukari , Bhuiyan Nazmul H. , Sun Qi , Turgeon Robert , van Wijk Klaas J.
Published: November 2010

C4 grasses, such as maize (Zea mays), have high photosynthetic efficiency through combined biochemical and structural adaptations. C4 photosynthesis is established along the developmental axis of the leaf blade, leading from an undifferentiated leaf base just above the ligule into highly specialized mesophyll cells (MCs) and bundle sheath cells (BSCs) at the tip. To resolve the kinetics of maize leaf development and C4 differentiation and to obtain a systems-level understanding of maize leaf formation, the accumulation profiles of proteomes of the leaf and the isolated BSCs with their vascular bundle along the developmental gradient were determined using large-scale mass spectrometry. This was complemented by extensive qualitative and quantitative microscopy analysis of structural features (e.g., Kranz anatomy, plasmodesmata, cell wall, and organelles). More than 4300 proteins were identified and functionally annotated. Developmental protein accumulation profiles and hierarchical cluster analysis then determined the kinetics of organelle biogenesis, formation of cellular structures, metabolism, and coexpression patterns. Two main expression clusters were observed, each divided in subclusters, suggesting that a limited number of developmental regulatory networks organize concerted protein accumulation along the leaf gradient. The coexpression with BSC and MC markers provided strong candidates for further analysis of C4 specialization, in particular transporters and biogenesis factors. Based on the integrated information, we describe five developmental transitions that provide a conceptual and practical template for further analysis. An online protein expression viewer is provided through the Plant Proteome Database.
IgG4 antibodies against rodents in laboratory animal workers do not protect against allergic sensitization
Authors: Krop E. J. M. , Doekes G. , Heederik D. J. J. , Aalberse R. C. , van der Zee J. S.
Published: November 2010

To cite this article: Krop EJM, Doekes G, Heederik DJJ, Aalberse RC, van der Zee JS. IgG4 antibodies against rodents in laboratory animal workers do not protect against allergic sensitization. Allergy 2011; 66: 517–522.

Background:  The modified Th2 response, defined as an IgG4 response in the absence of IgE, is suggested to protect against the development of allergic sensitization. However, studies suggesting this protective effect all had a cross‐sectional design, making it impossible to study the development of both responses.

Aim of the study:  We aimed to study the dynamics in IgG4 antibodies in relation to allergic sensitization in an occupational cohort of starting laboratory animal workers. Moreover, we studied the relation between exposure, antibody responses, atopy and self reported allergic symptoms.

Methods:  A total of 110 starting animal workers were followed for 2 years. IgG4 antibodies against rats and mice were assessed. Workers were tested for allergic sensitization and exposure to animal allergens was estimated. Symptom status was assessed using questionnaires.

Results:  Rat and mouse specific IgG4 antibodies were present before the development of allergy and did not significantly change over time. Allergic sensitization was related to exposure and atopic status but high levels of IgG4 showed no protective effect. In contrary, workers that developed mouse specific sensitization during follow up had higher levels of mouse specific IgG4. Symptoms were related to allergic sensitization and IgG4 levels did not influence that relationship.

Conclusions:  IgG4 antibodies are present before IgE antibodies develop and IgG4 levels are stable over time. In our occupational cohort, the modified Th2 response had no protective effect on development of sensitization or allergic symptoms.
Metformin attenuates ventricular hypertrophy by activating the AMP‐activated protein kinase–endothelial nitric oxide synthase pathway in rats
Authors: Zhang Cheng‐Xi , Pan Si‐Nian , Meng Rong‐Sen , Peng Chao‐Quan , Xiong Zhao‐Jun , Chen Bao‐Lin , Chen Guang‐Qin , Yao Feng‐Juan , Chen Yi‐Li , Ma Yue‐Dong , Dong Yu‐Gang
Published: November 2010

1. Metformin is an activator of AMP‐activated protein kinase (AMPK). Recent studies suggest that pharmacological activation of AMPK inhibits cardiac hypertrophy. In the present study, we examined whether long‐term treatment with metformin could attenuate ventricular hypertrophy in a rat model. The potential involvement of nitric oxide (NO) in the effects of metformin was also investigated.

2. Ventricular hypertrophy was established in rats by transaortic constriction (TAC). Starting 1 week after the TAC procedure, rats were treated with metformin (300 mg/kg per day, p.o.), NG‐nitro‐l‐arginine methyl ester (l‐NAME; 50 mg/kg per day, p.o.) or both for 8 weeks prior to the assessment of haemodynamic function and cardiac hypertrophy.

3. Cultured cardiomyocytes were used to examine the effects of metformin on the AMPK–endothelial NO synthase (eNOS) pathway. Cells were exposed to angiotensin (Ang) II (10−6 mol/L) for 24 h under serum‐free conditions in the presence or absence of metformin (10−3 mol/L), compound C (10−6 mol/L), l‐NAME (10−6 mol/L) or their combination. The rate of incorporation of [3H]‐leucine was determined, western blotting analyses of AMPK–eNOS, neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) were undertaken and the concentration of NO in culture media was determined.

4. Transaortic constriction resulted in significant haemodynamic dysfunction and ventricular hypertrophy. Myocardial fibrosis was also evident. Treatment with metformin improved haemodynamic function and significantly attenuated ventricular hypertrophy. Most of the effects of metformin were abolished by concomitant l‐NAME treatment. l‐NAME on its own had no effect on haemodynamic function and ventricular hypertrophy in TAC rats.

5. In cardiomyocytes, metformin inhibited AngII‐induced protein synthesis, an effect that was suppressed by the AMPK inhibitor compound C or the eNOS inhibitor l‐NAME. The improvement in cardiac structure and function following metformin treatment was associated with enhanced phosphorylation of AMPK and eNOS and increased NO production.

6. The findings of the present study indicate that long‐term treatment with metformin could attenuate ventricular hypertrophy induced by pressure overload via activation of AMPK and a downstream signalling pathway involving eNOS–NO.
Solitary, isolated metastatic disease to the kidney: Memorial Sloan‐Kettering Cancer Center experience
Authors: Adamy Ari , Von Bodman Christian , Ghoneim Tarek , Favaretto Ricardo L. , Bernstein Melanie , Russo Paul
Published: November 2010

Study Type – Therapy (case series)

Level of Evidence 4

What’s known on the subject? and What does the study add?

Usually malignant disease involving the kidneys is characterized by bilateral and multiple lesions in association with widespread dissemination of the primary tumour. Metastasis to the kidney as a solitary, isolated renal mass is an extremely rare event and little is known about its characteristics and outcomes.

Our study shows that kidney involvement by other tumours can occur as isolated solitary lesions and the kidney can be the first and only site of metastatic involvement. Of the 14 patients included in the study, 8 were alive at the last follow‐up and 4 without evidence of disease after nephrectomy. In this highly selected group of patients nephrectomy can be offered as a therapeutic option.

OBJECTIVE

• To analyse the clinical characteristics and outcomes of patients who underwent nephrectomy for solitary, isolated metastatic disease to the kidney.

PATIENTS AND METHODS

• From July 1989 to July 2009, we identified 13 patients who underwent nephrectomy for solitary metastasis to the kidney. Patients’ demographics, intra‐operative variables and outcomes are reported.

RESULTS

• The median age at nephrectomy was 52 years (range 33–79). Eleven patients (85%) had an incidentally discovered renal mass, whereas two patients (15%) presented with gross haematuria.

• Median time from initial surgery at the primary site to development of metastatic disease to the kidney was 63 months (range 9–136). No patient had evidence of disease at other sites at the time of nephrectomy. In seven patients (54%), the kidney was the first site of recurrence.

• The most common primary site was the lung in five patients (38%), followed by the colon in two (15%), chest wall in two (15%) and bone, brain, breast and salivary gland in one patient each (8%).

• Of the 14 procedures performed, eight (57%) were partial nephrectomy (PN) and six (43%) were radical nephrectomy (RN).

• Four patients died after progression from the primary tumour, all within 2 years of nephrectomy. One patient with a primary chondrosarcoma had no evidence of disease at last follow‐up and died from other causes 50 months after nephrectomy. The median follow‐up for the eight patients who were alive at last follow‐up was 30 months after nephrectomy. Four of these patients had no evidence of disease and four patients were alive with metastatic disease.

CONCLUSION

• Kidney involvement by metastatic disease can occur as isolated solitary lesions. Some patients will also have the kidney as the first and only site of metastatic involvement. The presence of an isolated renal metastasis should not be considered an end‐stage disease, and nephrectomy can be offered for highly selected patients as a therapeutic option.
Volar onlay urethroplasty for reconstruction of female urethra in recurrent stricture disease
Authors: Gozzi Christian , Roosen Alexander , Bastian Patrick J. , Karl Alexander , Stief Christian , Tritschler Stefan
Published: November 2010

Study Type – Therapy (case series)

Level of Evidence 4

What’s known on the subject? and What does the study add?

In spite of several suggestions that have been published recently, there is no standard procedure for therapy of recurrent female urethral stricture disease. Most of the published procedures are characterized by the time‐consuming use of an oral mucosal graft.

In the current study we present an effective and simple new technique for reconstruction of strictured female urethra, using a free labium minus graft.

OBJECTIVE

• To report our experience with a new and simple method of urethral repair with a volar onlay of free labium minus graft. Strictures of the female urethra are rare, and it is well accepted that the therapeutic options of dilation and urethrotomy are not lasting solutions as a result of their high recurrence rates. However, there is no consensus regarding the best way to reconstruct the female urethra in the case of stricture disease.

PATIENTS AND METHODS

• Four consecutive female patients with a long lasting history of recurrent urethral strictures underwent open urethroplasty with a volar situated free split thickness epidermal graft from the labium minus.

• The surgical technique is described and a short‐term follow‐up is presented.

RESULTS

• Operating time was 40–140 min (mean 105 min), and the graft measured between 2 × 1.5 cm and 3 × 2.5 cm. Follow‐up time was 11–19 months. Maximum urinary flow rate could be improved from a baseline of 9.4–11.2 mL/s (preoperatively, after intermittent use of dilation) to 19–23 mL/s.

• Postvoid residual urine volume was 0–50 mL preoperatively and no postvoid residual urine volume postoperatively.

• Urinary catheters were removed after 21 days. Urinary stress incontinence did not occur postoperatively. No complications related to the graft donor site were found.

CONCLUSIONS

• The reported data concerning a new therapeutic approach for the treatment of recurrent female urethral stricture show that a volar onlay urethroplasty represents a feasible, safe and simple surgical method.

• Larger series with long‐term follow‐up are needed for further evaluation.
Neurocognition of New Word Learning in the Native Tongue: Lessons From the Ancient Farming Equipment Paradigm
Authors: Laine Matti , Salmelin Riitta
Published: November 2010

Here we review behavioral, neuroimaging, and neuropharmacological studies using a word learning task labeled as the Ancient Farming Equipment paradigm. This task has been used to explore the neural correlates of explicit learning and maintenance of new names for novel objects in the native tongue. The main conclusions drawn from these studies are as follows: (a) Retrieval of both the newly learned and familiar names is subserved by predominantly left hemispheric cortical regions; (b) within this network, retrieval of newly learned words can be accomplished in different ways depending on the exact form of training; (c) patient studies indicate that episodic memory mechanisms subserved by hippocampal structures are related to word acquisition rather than to long‐term maintenance of newly learned words; (d) explicit learning and maintenance of novel words can be facilitated by neuropharmacological manipulation that boosts the dopaminergic system; and (b) neural events following completed training may predict long‐term retention of newly learned words.
Cognitive and Neural Mechanisms Sustaining Rule Learning From Speech
Authors: De Diego‐Balaguer Ruth , Lopez‐Barroso Diana
Published: November 2010

Learners of a new language have to extract words and the rules from speech. Learners are endowed with the capacity to extract statistical regularities from their environment allowing them to extract words from continuous speech in the absence of other cues. However, it has been proposed that natural languages have an intrinsic cue: prosodic information. This cue seems to trigger the application of different computational resources that allows the extraction of rules. This review summarizes work indicating that attention and working memory are critical in the early stages of language acquisition, in the absence of semantic information. Event‐related potentials while participants learned artificial languages with embedded morphological rules show a dissociation between the brain responses associated to word and rule learning. The results indicate that salient cues such as prosody help to direct attention biasing perception to ignore irrelevant information and attend to the relevant segments containing the rule, shifting from word acquisition to rule extraction. Finally, data from individual differences in brain connectivity related to phonological working memory and data from brain‐lesioned patients point to the basal ganglia as a coordinator structure among language, working memory, and attention through its rich connections with brain areas responsible for these functions.
Artificial Language Learning in Adults and Children
Authors: Folia Vasiliki , Uddén Julia , De Vries Meinou , Forkstam Christian , Petersson Karl Magnus
Published: November 2010

This article briefly reviews some recent work on artificial language learning in children and adults. The final part of the article is devoted to a theoretical formulation of the language learning problem from a mechanistic neurobiological viewpoint and we show that it is logically possible to combine the notion of innate language constraints with, for example, the notion of domain general learning mechanisms. A growing body of empirical evidence suggests that the mechanisms involved in artificial language learning and in structured sequence processing are shared with those of natural language acquisition and natural language processing. Finally, by theoretically analyzing a formal learning model, we highlight Fodor's insight that it is logically possible to combine innate, domain‐specific constraints with domain‐general learning mechanisms.
How Sure Can You Be? A Framework for Considering Delivery Uncertainty in Benefit Assessments Based on Stated Preference Methods
Authors: Glenk Klaus , Colombo Sergio
Published: November 2010

The economic valuation of benefits resulting from environmental policies and interventions often assumes that environmental outcomes are certain. In fact, these outcomes are typically uncertain. This article proposes a methodological approach to incorporate delivery uncertainty into benefit estimation based on stated preference methods. In the study design of a choice experiment survey on land‐based climate change mitigation, we explicitly include delivery uncertainty as the risk that a proposed mitigation project fails to deliver emission savings. We find that respondents’ preferences do not change significantly after being confronted with choices that included risk of failure. However, failure risk itself does have an important impact on the preferences for delivering emission reductions. We show that delivery uncertainty can have a large impact on stated preference estimation of benefits of public programmes. This result should condition conclusions drawn from ex‐ante environmental cost‐benefit analyses that make use of such benefit estimates.
Women’s Experiences of Empowerment in a Planned Home Birth: A Swedish Population‐based Study
Authors: Lindgren Helena , Erlandsson Kerstin
Published: November 2010

Abstract:  Background:  Childbirth can be an empowering event in a woman’s life. However, little is known about women’s own perceptions of power and empowering sources during childbirth. This study aimed to describe the factors experienced as empowering during a planned home birth.

Methods:  The inclusion criteria were women in Sweden who had a planned home birth between 1992 and 2005. All the women (n = 735) who agreed to participate received one questionnaire for each planned home birth. A total of 1,038 questionnaires were sent to the women. The written birth stories were analyzed using content analysis and descriptive statistics.

Results:  In the analysis of the participants’ birth experience four categories and one overall theme emerged from the stories. The categories identified were sensations, guidance, tacit support, and identification of needs. Greater emphasis was put on guidance among first‐time mothers than among multiparas, for whom tacit support was identified as the most empowering factor. The overall theme was identified as “resting in acceptance of the process.” The empowerment women expressed by achieving and maintaining a sense of control allowed them to rest in acceptance of the efforts that are part of a normal birth.

Conclusion:  Women who choose to give birth at home find empowering sources within themselves from their environment and from the active and passive support of persons they have chosen to be present at the birth. (BIRTH 37:4 December 2010)
Home Birth: Gone Away, Gone Astray, and Here To Stay
Authors: Keirse Marc J.N.C.
Published: November 2010

Abstract:  Home birth has attracted a great deal of attention of late, culminating in a meta‐analysis to assess its risks for mother and baby. Mothers were estimated to be 2.6 times more likely to die and babies 3 times more likely to die from a planned home birth than from a planned hospital birth. The actual data on which these estimates were based demonstrate that meta‐analysis can be developed into an art that suits whatever purpose its authors hope to achieve. Combining studies of home versus hospital, without differentiating what is inside them, where they are, and what is around them, is akin to producing a fruit salad with potatoes, pineapples, and celery. (BIRTH 37:4 December 2010)
Asymmetric Information, Long‐Term Care Insurance, and Annuities: The Case for Bundled Contracts
Authors: Webb David C.
Published: November 2010

Abstract

This article examines the markets for long‐term care insurance and annuities when there is asymmetric information and there are costs of administering contracts. Individuals differ in terms of their risk aversion. Risk‐averse individuals take more care of their health and are relatively high risk in the annuities market and relatively low risk in the long‐term care insurance market. In the long‐term care insurance market, both separating and partial‐pooling equilibria are possible. However, in the stand‐alone annuity market, only separating equilibria are possible. We show, consistent with the extant empirical research, that in the presence of administration costs the more risk‐averse individuals may buy relatively more long‐term care insurance and more annuity coverage. Under the same assumptions, we show that equilibria exist with bundled contracts that Pareto dominate the outcomes with stand‐alone contracts and are robust to competition from stand‐alone contracts. The remaining empirical puzzle is to explain why bundled contracts are such a small share of the voluntary annuity market.
Time Deductibles as Screening Devices: Competitive Markets
Authors: Spreeuw Jaap , Karlsson Martin
Published: November 2010

Abstract

Seminal papers on asymmetric information in competitive insurance markets, analyzing the monetary deductible as a screening device, show that any existing equilibrium is of a separating type. High risks buy complete insurance, whereas low risks buy partial insurance—and this result holds for the Nash behavior as well as for the Wilson foresight. In this article, we analyze the strength of screening based on limitations to the period of coverage of the contract. We show that in this case (1) the Nash equilibrium may entail low risks not purchasing any insurance at all, and (2) under the Wilson foresight, a pooling equilibrium may exist.
Adverse Selection and the Opaqueness of Insurers
Authors: Zhang Tao , Cox Larry A. , Van Ness Robert A.
Published: November 2010

Abstract

While adverse selection problems between insureds and insurers are well known to insurance researchers, few explore adverse selection in the insurance industry from a capital markets perspective. This study examines adverse selection in the quoted prices of insurers' common stocks with a particular focus on the opacity of both asset portfolios and underwriting liabilities. We find that more opaque underwriting lines result in greater adverse selection costs for property‐casualty (P‐C) insurers. A similar effect is not apparent for life‐health (L‐H) insurers and we find no effect of asset opaqueness on adverse selection for either L‐H or P‐C insurers.
On the Role of Patience in an Insurance Market With Asymmetric Information
Authors: Sonnenholzner Michael , Wambach Achim
Published: November 2010

Abstract

We analyze a two‐period competitive insurance market that is characterized by the simultaneous presence of moral hazard and adverse selection with regard to consumer time preferences. It is shown that there exists an equilibrium in which patient consumers use high effort and buy an insurance contract with high coverage, whereas impatient consumers use low effort and buy a contract with low coverage or even remain uninsured. This finding may help to explain why the opposite of adverse selection with regard to risk types can sometimes be observed empirically.