bluuebunny/crossref_metadata_2025 huggingface dataset:
Individual Differences in Asymmetric Resting-State Frontal Cortical Activity Modulate ERPs and Performance in a Global-Local Attention Task
Authors: Boksem Maarten A. S. , Kostermans Evelien , Tops Mattie , De Cremer David
Published: April 2012

Recent research has demonstrated that individual differences in approach motivation modulate attentional scope. In turn, approach and inhibition have been related to different neural systems that are associated with asymmetries in relative frontal activity (RFA). Here, we investigated whether such individual differences in asymmetric hemispheric activity during rest, and self-report measures of approach motivation (as measured by the behavioral inhibition system, BIS/behavioral activation system, BAS scales) would be predictive of the efficiency of attentional processing of global and local visual information, as indexed by event-related potentials (ERPs) and performance measures. In the reported experiment, participants performed a visual attention task in which they were required to either attend to the global shape or the local components of presented stimuli. Electroencephalogram was recorded during task performance and during an initial “resting state” measurement. The results showed that only the BAS-Reward Responsiveness subscale was associated with left RFA during rest, while BIS, BAS-Drive, and BAS-Fun Seeking were associated with more right-lateralized RFA. Importantly, left RFA during the “resting state” measurement was associated with increased P3 (right-lateralized) amplitudes and decreased P3 latencies on trials requiring a global focus. In turn, these ERPs were associated with enhanced performance on trials requiring a global focus. These results provide the first evidence for a positive association between left RFA during rest and increased efficiency of right-lateralized brain mechanisms that are involved in processing global information.
Further Evidence for the Independent Reflex-Eliciting and Reflex-Inhibiting Effects of a Startle-Blink Eliciting Stimulus
Authors: Krauter E. Evan , Cruickshank Bridgette C. , Avery Michael C.
Published: April 2012

A small change in the environment (a prepulse) that just precedes a startle-eliciting stimulus can reduce the size of the elicited reflex, but a prepulse does not appear to diminish the ability of the startle-eliciting stimulus to depress a startle response elicited a little later. The reflex-eliciting and reflex-modifying effects of startle stimuli seem to be independent. However, most support for this observation rests on a failure to reject the null hypothesis, and relatively little of this research has employed the acoustic startle blink in human beings. The purpose of the present study was to provide additional evidence on this issue. Participants (n = 20) encountered trials in which a prepulse (p) and two 103 dB(A) blink-eliciting noise bursts (S1 and S2) were given in succession. The prepulse (a synchronous word and tone) occurred 150 ms prior to S1. The prepulse inhibited the startle blink to S1, and S1 depressed the blink elicited 1.5 s later by S2. However, regardless of whether p inhibited the blink to S1, S1 maintained the same capacity to depress the blink to S2. In contrast, a softer S1 (88 dB(A); S1attenuated), which produced a blink nearly matching the size of the prepulse-inhibited blink, did not significantly depress the response to S2. Participants also judged the loudness of S1 and S2. The prepulse reduced the perceived intensity of S1, but much less so than caused by reducing the actual intensity of S1, and proportionally much less so than the prepulse reduced the blink to S1. These results provide further evidence for independent reflex-eliciting and reflex-modifying effects of a startle-eliciting stimulus and argue against the notion that prepulses strongly reduce the general sensory impact of the startle stimulus.
Attention Bias to Threat in Anxiety-Prone Individuals
Authors: Cocia Ioana R. , Uscătescu Lavinia C. , Rusu Alina S.
Published: April 2012

There is considerable controversy around the factors influencing the attentional biases involved in anxiety, controversies pinpointing to the role of trait anxiety (TA) in these biases. Previous studies have disregarded psychophysiological factors, such as cardiac vagal control, from the relation between TA and attention biases to threat, though cardiac vagal control serves as a proxy of attention regulation. By using a spatial cueing task, the present correlational study examines cardiac vagal tone as a moderator of the relation between TA and attention biases to threat. Cardiac vagal tone was indexed by high-frequency heart-rate variability (HF-HRV) and recorded, at baseline, from participants with high trait anxiety (HTA, N = 34) or low trait anxiety (LTA, N = 40). Our data indicate that HF-HRV significantly moderates the relation between TA and disengagement bias, but does not moderate the relation between TA and engagement bias. Extended analysis on the significant moderation showed that HF-HRV moderated the relation between TA and disengagement bias in the case of the participants with mean to low HF-HRV values. This was not the case for the participants with high values of HF-HRV. Our results suggest implications for redefining groups at risk for anxiety disorders, as well as future considerations of the cardiac vagal tone in attention bias research.
Blood Levels of Serotonin Are Differentially Affected by Romantic Love in Men and Women
Authors: Langeslag Sandra J. E. , van der Veen Frederik M. , Fekkes Durk
Published: April 2012

People who are in love think about their beloved the whole day, which is supposed to be associated with serotonin. The research questions were how peripheral serotonin levels differ between individuals that are in love compared to individuals that are not in love, and how these levels are associated with obsessive thinking about the beloved. Because gender differences exist in romantic love and in the serotonergic system, gender differences were tested. Twenty participants who were in love (10 men) and 20 who were not in love (10 men) completed several questionnaires, and plasma and serum serotonin levels were assessed. The men who were in love had lower serotonin levels than the men who were not in love, while women showed the opposite pattern. The participants that were in love reported obsessive thinking about their beloved for 65% of their waking hours. In women, obsessive thinking about the beloved was associated with an increased serotonin level in serum. The serotonergic system seems to play a role in romantic love, but the effects appear opposite for men and women.
The geochemistry of the Yangtze River: Seasonality of concentrations and temporal trends of chemical loads
Authors: Müller Beat , Berg Michael , Pernet‐Coudrier Benoît , Qi Weixiao , Liu Huijuan
Published: May 2012

The Yangtze is the largest river in Asia and its water composition reflects the activities of about 400 Mio people in its catchment. Its chemical loads have a large impact on the biogeochemistry of the East China Sea. We discuss and quantify the annual dynamics of major ions, nutrients, and trace elements from samples collected monthly at Datong Station from May 2009 to June 2010. The Yangtze today carries 192 × 106 tons of total dissolved solids annually to the East China Sea, which is an increase of 25% compared to the average of 1958–1990. While the loads of dissolved silica (SiO2), dissolved inorganic carbon (DIC), Ca2+ and Mg2+compared well with the long‐term averages since the 1950s, loads of Na+, Cl−, SO42−, have tripled since 1958–1990. The increase of SO42− is attributed to the burning of coal in the catchment, and 18% of the F− load is estimated to originate from this source. The increase of Na+ and Cl−loads may be anthropogenic as well. The load of dissolved inorganic nitrogen (DIN) has increased 15 fold since the early measurements around 1970 and amounts to 1.6 Mt‐N/yr today. The particulate concentrations of the typical anthropogenic trace metals Cd, Cr, Cu, Ni, Pb, and Zn showed enrichment factors between 0.7 – 7 compared to the natural background. Their annual peak concentrations all exceeded the quality targets recommended by the EC up to two times. However, the load of trace elements at Datong decreased by 73–86% (As: 50%) in the past ten years.
Surface estimates of the Atlantic overturning in density space in an eddy‐permitting ocean model
Authors: Grist Jeremy P. , Josey Simon A. , Marsh Robert
Published: May 2012

A method to estimate the variability of the Atlantic meridional overturning circulation (AMOC) from surface observations is investigated using an eddy‐permitting ocean‐only model (ORCA‐025). The approach is based on the estimate of dense water formation from surface density fluxes. Analysis using 78 years of two repeat forcing model runs reveals that the surface forcing–based estimate accounts for over 60% of the interannual AMOC variability in σ0 coordinates between 37°N and 51°N. The analysis provides correlations between surface‐forced and actual overturning that exceed those obtained in an earlier analysis of a coarser resolution‐coupled model. Our results indicate that, in accordance with theoretical considerations behind the method, it provides a better estimate of the overturning in density coordinates than in z coordinates in subpolar latitudes. By considering shorter segments of the model run, it is shown that correlations are particularly enhanced by the method's ability to capture large decadal scale AMOC fluctuations. The inclusion of the anomalous Ekman transport increases the amount of variance explained by an average 16% throughout the North Atlantic and provides the greatest potential for estimating the variability of the AMOC in density space between 33°N and 54°N. In that latitude range, 70–84% of the variance is explained and the root‐mean‐square difference is less than 1 Sv when the full run is considered.
Assessing the predictive capabilities of isotropic, eddy viscosity Reynolds‐averaged turbulence models in a natural‐like meandering channel
Authors: Kang Seokkoo , Sotiropoulos Fotis
Published: May 2012

The predictive capabilities of an isotropic, eddy viscosity turbulence model for closing the unsteady Reynolds‐averaged Navier‐Stokes (RANS) equations are systematically investigated by simulating turbulent flow through a field‐scale meandering channel and comparing the computed results with the large‐eddy simulation (LES) of the same flow recently reported by Kang and Sotiropoulos (2011). To facilitate the comparison of the two turbulence models, both RANS simulation and LES are carried on exactly the same grid with the same numerical method. The comparisons show that while the RANS model captures the curvature‐driven secondary flow within the bend, it fails completely to predict other key flow features in the channel, which are predicted by the LES and also observed in flow visualization experiments. These features include the inner and outer bank shear layers, the outer bank secondary cell, and the inner bank horizontal recirculation zone. By analyzing the results of the LES, we conclusively show that flow features not predicted by the RANS calculation are located in regions of the flow with high levels of turbulence anisotropy. The extent of these regions and, consequently, the degree of disagreement between the RANS and LES predictions are shown to depend on the stream geometry and the flow rate. Our results underscore the major challenges confronting the computationally expedient, isotropic RANS models, which are widely used today in three‐dimensional hydrodynamic and morphodynamic simulations.
Comparing low‐frequency and intermittent variability in comprehensive climate models through nonlinear Laplacian spectral analysis
Authors: Giannakis Dimitrios , Majda Andrew J.
Published: May 2012

Nonlinear Laplacian spectral analysis (NLSA) is a recently developed technique for spatiotemporal analysis of high‐dimensional data, which represents temporal patterns via natural orthonormal basis functions on the nonlinear data manifold. Through such basis functions, determined efficiently via graph‐theoretic algorithms, NLSA captures intermittency, rare events, and other nonlinear dynamical features which are not accessible through linear approaches (e.g., singular spectrum analysis (SSA)). Here, we apply NLSA to study North Pacific SST monthly data from the CCSM3 and ECHAM5/MPI‐OM models. Without performing spatial coarse graining (i.e., operating in ambient‐space dimensions up to 1.6 × 105after lagged embedding), or seasonal‐cycle subtraction, the method reveals families of periodic, low‐frequency, and intermittent spatiotemporal modes. The intermittent modes, which describe variability in the Western and Eastern boundary currents, as well as variability in the subtropical gyre with year‐to‐year reemergence, are not captured by SSA, yet are likely to have high significance in a predictive context and utility in cross‐model comparisons.
A new model for formation of artificial ducts due to ionospheric HF‐heating
Authors: Milikh G. M. , Demekhov A. , Vartanyan A. , Mishin E. V. , Huba J.
Published: May 2012

We present the results of numerical simulations of artificial ducts during high‐power HF heating performed by a novel model accounting for the effect of self‐action. This effect interferes with the HF‐plasma matching in the heated region and hence with electron heating. The model satisfactorily explains recent experimental observations. It helps for choosing the heating parameters optimal for duct formation, such as proper duration of the heating pulse and its frequency. It also suggests that distortion of the ducts caused by the self‐action effect can be avoided by down‐chirping the heating frequency. The down‐chirping rates needed to suppress such distortions are evaluated.
Spatial and temporal variation of the impact of an extreme Saharan dust event
Authors: Cabello M. , Orza J. A. G. , Barrero M. A. , Gordo E. , Berasaluce A. , Cantón L. , Dueñas C. , Fernández M. C. , Pérez M.
Published: May 2012

The impact on PM10, meteorology and visibility of the severe Saharan dust outbreak registered in Europe in October 2008 is evaluated in detail in mainland Spain and the Balearic Islands. Data from a large number of air quality stations (261), METAR observations at 39 airports, besides records from meteorological networks, were used. Information from dispersion models, satellite observations, synoptic charts and back‐trajectory analysis, supported the interpretation. During the event, 89% of the monitoring stations exceeded the daily limit value. The highest daily averaged PM10 concentration across Spain ranged from 378 to 18μg m−3, following a hyperbolic decay with increasing latitude. An opposite relationship between visibility and PM10 was found for data at 12 UTC. The strength of the episode may be related to strong subsidence at low levels over the Iberian Peninsula.
Van der Pol and the history of relaxation oscillations: Toward the emergence of a concept
Authors: Ginoux Jean-Marc , Letellier Christophe
Published: May 2012

Relaxation oscillations are commonly associated with the name of Balthazar van der Pol via his paper (Philosophical Magazine, 1926) in which he apparently introduced this terminology to describe the nonlinear oscillations produced by self-sustained oscillating systems such as a triode circuit. Our aim is to investigate how relaxation oscillations were actually discovered. Browsing the literature from the late 19th century, we identified four self-oscillating systems in which relaxation oscillations have been observed: (i) the series dynamo machine conducted by Gérard-Lescuyer (1880), (ii) the musical arc discovered by Duddell (1901) and investigated by Blondel (1905), (iii) the triode invented by de Forest (1907), and (iv) the multivibrator elaborated by Abraham and Bloch (1917). The differential equation describing such a self-oscillating system was proposed by Poincaré for the musical arc (1908), by Janet for the series dynamo machine (1919), and by Blondel for the triode (1919). Once Janet (1919) established that these three self-oscillating systems can be described by the same equation, van der Pol proposed (1926) a generic dimensionless equation which captures the relevant dynamical properties shared by these systems. Van der Pol’s contributions during the period of 1926-1930 were investigated to show how, with Le Corbeiller’s help, he popularized the “relaxation oscillations” using the previous experiments as examples and, turned them into a concept.
An ab initio molecular dynamics study on hydrogen bonds between water molecules
Authors: Pan Zhang , Chen Jing , Lü Gang , Geng Yi-Zhao , Zhang Hui , Ji Qing
Published: May 2012

The quantitative estimation of the total interaction energy of a molecular system containing hydrogen bonds (H bonds) depends largely on how to identify H bonding. The conventional geometric criteria of H bonding are simple and convenient in application, but a certain amount of non-H bonding cases are also identified as H bonding. In order to investigate the wrong identification, we carry out a systematic calculation on the interaction energy of two water molecules at various orientation angles and distances using ab initio molecular dynamics method with the dispersion correction for the Becke-Lee-Yang-Parr (BLYP) functionals. It is shown that, at many orientation angles and distances, the interaction energies of the two water molecules exceed the energy criterion of the H bond, but they are still identified as H-bonded by the conventional “distance-angle” criteria. It is found that in these non-H bonding cases the wrong identification is mainly caused by short-range interaction between the two neighbouring water molecules. We thus propose that, in addition to the conventional distance and angle criteria of H bonding, the distance dH⋅⋅⋅H between the two neighbouring hydrogen atoms of the two water molecules should also be taken as a criterion, and the distance rO⋅⋅⋅H between the hydrogen atom of the H-bond donor molecule and the oxygen atom of the acceptor molecule should be restricted by a lower limit. When dH⋅⋅⋅H and rO⋅⋅⋅H are small (e.g., dH⋅⋅⋅H < 2.0 Å and rO⋅⋅⋅H < 1.62 Å), the repulsion between the two neighbouring atoms increases the total energy of the two water molecules dramatically and apparently weakens the binding of the water dimer. A statistical analysis and comparison of the numbers of the H bonds identified by using different criteria have been conducted on a Car-Parrinello ab initio molecular dynamics simulation with dispersion correction for a system of 64 water molecules at near-ambient temperature. They show that the majority of the H-bonds counted by using the conventional criteria combined with the dH⋅⋅⋅H criterion and the restriction of rO⋅⋅⋅H match what is identified by the binding energy criteria (e.g., E ≤ −10 kJ/mol), while some of them still have a binding energy that exceeds the energy criterion, indicating that the complicated quantum effects in H bonding can only be described by the three geometric parameters to a certain extent.
In-situ comprehensive calibration of a tri-port nano-electro-mechanical device
Authors: Collin E. , Defoort M. , Lulla K. , Moutonet T. , Heron J.-S. , Bourgeois O. , Bunkov Yu. M. , Godfrin H.
Published: May 2012

We report on experiments performed in vacuum and at cryogenic temperatures on a tri-port nano-electro-mechanical (NEMS) device. One port is a very nonlinear capacitive actuation, while the two others implement the magnetomotive scheme with a linear input force port and a (quasi-linear) output velocity port. We present an experimental method enabling a full characterization of the nanomechanical device harmonic response: the nonlinear capacitance function C(x) is derived, and the normal parameters k and m (spring constant and mass) of the mode under study are measured through a careful definition of the motion (in meters) and of the applied forces (in Newtons). These results are obtained with a series of purely electric measurements performed without disconnecting/reconnecting the device, and rely only on known dc properties of the circuit, making use of a thermometric property of the oscillator itself: we use the Young modulus of the coating metal as a thermometer, and the resistivity for Joule heating. The setup requires only three connecting lines without any particular matching, enabling the preservation of a high impedance NEMS environment even at MHz frequencies. The experimental data are fit to a detailed electrical and thermal model of the NEMS device, demonstrating a complete understanding of its dynamics. These methods are quite general and can be adapted (as a whole, or in parts) to a large variety of electromechanical devices.
Measurements of hohlraum-produced fast ions
Authors: Zylstra A. B. , Li C. K. , Séguin F. H. , Rosenberg M. J. , Rinderknecht H. G. , Sinenian N. , Frenje J. A. , Petrasso R. D. , Izumi N. , Amendt P. A. , Landen O. L. , Koch J. A.
Published: May 2012

We report the first fast ion measurements in indirect-drive experiments, which were taken on OMEGA hohlraum and halfraum shots using simple filtered CR-39, a nuclear track detector, and a charged-particle spectrometer. Protons are observed in two energy regimes that are associated with different fast ion production mechanisms. In the first, resonance absorption at the hohlraum wall early in the laser pulse accelerates runaway electrons. In the second, fast electrons are produced with high energy from the two-plasmon decay instability in the exploding laser entrance hole, or from stimulated Raman scattering in the underdense gas fill. In both cases, the runaway electrons set up a strong electrostatic field that accelerates the measured ions. The former mechanism is observed to have an energy conversion efficiency ∼(0.6-4)×10-4 into fast protons depending on the hohlraum and drive. The latter mechanism has an estimated conversion efficiency from the main drive of ∼(0.5-2)×10-5 depending on the assumptions made.
Magnetic properties of ZnO nanoclusters
Authors: Zhao X. G. , Tang Z.
Published: May 2012

First-principles calculations were employed to study the magnetic properties of ZnO nanoclusters (NCs). It is demonstrated that the magnetism of the ZnO nanoclusters is dominated by the dangling-bond states of the surface oxygen ions surrounded by two Zn cations. Such surface-state driven magnetism can be completely destroyed by hydrogen passivation and thus is very sensitive to the chemical environments of the NCs. The theory indicates that magnetism may be steadily observed in appropriately encapsulated ZnO nanoparticles or around their grain boundaries, which is consistent with the previously reported experiments.
Screened hybrid density functional study on Sr2Nb2O7 for visible light photocatalysis
Authors: Nisar J. , Pathak B. , Ahuja R.
Published: May 2012

The electronic structure of pure Sr2Nb2O7 and its electronic band position are being aligned with respect to the water oxidation/reduction potential level using hybrid functional (HSE06) theory. The experimental band gap (3.90 eV) of pure Sr2Nb2O7 can be reproduced (3.92 eV) using this level of theory. The cationic-anionic co-doping (Mo-N) in layered perovskite Sr2Nb2O7 structure reduces the band gap significantly, and its electronic band position is excellent for the visible-light photocatalysis. The respective cationic and anionic mono-doped systems create an occupied or unoccupied impurity states in the band gap, which can reduce the efficiency of the photocatalysis.
Natural and sexual selection in a monogamous historical human population
Authors: Courtiol Alexandre , Pettay Jenni E. , Jokela Markus , Rotkirch Anna , Lummaa Virpi
Published: May 2012

Whether and how human populations exposed to the agricultural revolution are still affected by Darwinian selection remains controversial among social scientists, biologists, and the general public. Although methods of studying selection in natural populations are well established, our understanding of selection in humans has been limited by the availability of suitable datasets. Here, we present a study comparing the maximum strengths of natural and sexual selection in humans that includes the effects of sex and wealth on different episodes of selection. Our dataset was compiled from church records of preindustrial Finnish populations characterized by socially imposed monogamy, and it contains a complete distribution of survival, mating, and reproductive success for 5,923 individuals born 1760–1849. Individual differences in early survival and fertility (natural selection) were responsible for most variation in fitness, even among wealthier individuals. Variance in mating success explained most of the higher variance in reproductive success in males compared with females, but mating success also influenced reproductive success in females, allowing for sexual selection to operate in both sexes. The detected opportunity for selection is in line with measurements for other species but higher than most previous reports for human samples. This disparity results from biological, demographic, economic, and social differences across populations as well as from failures by most previous studies to account for variation in fitness introduced by nonreproductive individuals. Our results emphasize that the demographic, cultural, and technological changes of the last 10,000 y did not preclude the potential for natural and sexual selection in our species.
Tumor-targeted TNFα stabilizes tumor vessels and enhances active immunotherapy
Authors: Johansson Anna , Hamzah Juliana , Payne Christine J. , Ganss Ruth
Published: May 2012

Solid tumors are intrinsically resistant to immune rejection. Abnormal tumor vasculature can act as a barrier for immune cell migration into tumors. We tested whether targeting IFNγ and/or TNFα into pancreatic neuroendocrine tumors can alleviate immune suppression. We found that intratumoral IFNγ causes rapid vessel loss, which does not support anti-tumor immunity. In contrast, low-dose TNFα enhances T-cell infiltration and overall survival, an effect that is exclusively mediated by CD8+effector cells. Intriguingly, lymphocyte influx does not correlate with increased vessel leakiness. Instead, low-dose TNFα stabilizes the vascular network and improves vessel perfusion. Inflammatory vessel remodeling is, at least in part, mediated by tumor-resident macrophages that are reprogrammed to secrete immune and angiogenic modulators. Moreover, inflammatory vessel remodeling with low-dose TNFα substantially improves antitumor vaccination or adoptive T-cell therapy. Thus, low-dose TNFα promotes both vessel remodeling and antitumor immune responses and acts as a potent adjuvant for active immunotherapy.
Improving the efficiency of water splitting in dye-sensitized solar cells by using a biomimetic electron transfer mediator
Authors: Zhao Yixin , Swierk John R. , Megiatto Jackson D. , Sherman Benjamin , Youngblood W. Justin , Qin Dongdong , Lentz Deanna M. , Moore Ana L. , Moore Thomas A. , Gust Devens , Mallouk Thomas E.
Published: May 2012

Photoelectrochemical water splitting directly converts solar energy to chemical energy stored in hydrogen, a high energy density fuel. Although water splitting using semiconductor photoelectrodes has been studied for more than 40 years, it has only recently been demonstrated using dye-sensitized electrodes. The quantum yield for water splitting in these dye-based systems has, so far, been very low because the charge recombination reaction is faster than the catalytic four-electron oxidation of water to oxygen. We show here that the quantum yield is more than doubled by incorporating an electron transfer mediator that is mimetic of the tyrosine-histidine mediator in Photosystem II. The mediator molecule is covalently bound to the water oxidation catalyst, a colloidal iridium oxide particle, and is coadsorbed onto a porous titanium dioxide electrode with a Ruthenium polypyridyl sensitizer. As in the natural photosynthetic system, this molecule mediates electron transfer between a relatively slow metal oxide catalyst that oxidizes water on the millisecond timescale and a dye molecule that is oxidized in a fast light-induced electron transfer reaction. The presence of the mediator molecule in the system results in photoelectrochemical water splitting with an internal quantum efficiency of approximately 2.3% using blue light.
Changing resonator geometry to boost sound power decouples size and song frequency in a small insect
Authors: Mhatre Natasha , Montealegre-Z Fernando , Balakrishnan Rohini , Robert Daniel
Published: May 2012

Despite their small size, some insects, such as crickets, can produce high amplitude mating songs by rubbing their wings together. By exploiting structural resonance for sound radiation, crickets broadcast species-specific songs at a sharply tuned frequency. Such songs enhance the range of signal transmission, contain information about the signaler’s quality, and allow mate choice. The production of pure tones requires elaborate structural mechanisms that control and sustain resonance at the species-specific frequency. Tree crickets differ sharply from this scheme. Although they use a resonant system to produce sound, tree crickets can produce high amplitude songs at different frequencies, varying by as much as an octave. Based on an investigation of the driving mechanism and the resonant system, using laser Doppler vibrometry and finite element modeling, we show that it is the distinctive geometry of the crickets’ forewings (the resonant system) that is responsible for their capacity to vary frequency. The long, enlarged wings enable the production of high amplitude songs; however, as a mechanical consequence of the high aspect ratio, the resonant structures have multiple resonant modes that are similar in frequency. The drive produced by the singing apparatus cannot, therefore, be locked to a single frequency, and different resonant modes can easily be engaged, allowing individual males to vary the carrier frequency of their songs. Such flexibility in sound production, decoupling body size and song frequency, has important implications for conventional views of mate choice, and offers inspiration for the design of miniature, multifrequency, resonant acoustic radiators.
Brain anomalies in children exposed prenatally to a common organophosphate pesticide
Authors: Rauh Virginia A. , Perera Frederica P. , Horton Megan K. , Whyatt Robin M. , Bansal Ravi , Hao Xuejun , Liu Jun , Barr Dana Boyd , Slotkin Theodore A. , Peterson Bradley S.
Published: May 2012

Prenatal exposure to chlorpyrifos (CPF), an organophosphate insecticide, is associated with neurobehavioral deficits in humans and animal models. We investigated associations between CPF exposure and brain morphology using magnetic resonance imaging in 40 children, 5.9–11.2 y, selected from a nonclinical, representative community-based cohort. Twenty high-exposure children (upper tertile of CPF concentrations in umbilical cord blood) were compared with 20 low-exposure children on cortical surface features; all participants had minimal prenatal exposure to environmental tobacco smoke and polycyclic aromatic hydrocarbons. High CPF exposure was associated with enlargement of superior temporal, posterior middle temporal, and inferior postcentral gyri bilaterally, and enlarged superior frontal gyrus, gyrus rectus, cuneus, and precuneus along the mesial wall of the right hemisphere. Group differences were derived from exposure effects on underlying white matter. A significant exposure × IQ interaction was derived from CPF disruption of normal IQ associations with surface measures in low-exposure children. In preliminary analyses, high-exposure children did not show expected sex differences in the right inferior parietal lobule and superior marginal gyrus, and displayed reversal of sex differences in the right mesial superior frontal gyrus, consistent with disruption by CPF of normal behavioral sexual dimorphisms reported in animal models. High-exposure children also showed frontal and parietal cortical thinning, and an inverse dose–response relationship between CPF and cortical thickness. This study reports significant associations of prenatal exposure to a widely used environmental neurotoxicant, at standard use levels, with structural changes in the developing human brain.
Reversal of muscle insulin resistance by weight reduction in young, lean, insulin-resistant offspring of parents with type 2 diabetes
Authors: Petersen Kitt Falk , Dufour Sylvie , Morino Katsutaro , Yoo Peter S. , Cline Gary W. , Shulman Gerald I.
Published: May 2012

To examine the role of intramyocellular lipid (IMCL) accumulation as well as circulating cytokines, branched-chain amino acids and acylcarnitines in the pathogenesis of muscle insulin resistance in healthy, young, lean insulin-resistant offspring of parents with type 2 diabetes (IR offspring), we measured these factors in plasma and used
1
H magnetic resonance spectroscopy to assess IMCL content and hyperinsulinemic-euglycemic clamps using [6,6-
2
H
2
] glucose to assess rates of insulin-stimulated peripheral glucose metabolism before and after weight reduction. Seven lean (body mass index < 25 kg/m
2
), young, sedentary IR offspring were studied before and after weight stabilization following a hypocaloric (1,200 Kcal) diet for ∼9 wks. This diet resulted in an average weight loss of 4.1 ± 0.6 kg (
P
< 0.0005), which was associated with an ∼30% reduction of IMCL from 1.1 ± 0.2% to 0.8 ± 0.1% (
P =
0.045) and an ∼30% improvement in insulin-stimulated muscle glucose uptake [3.7 ± 0.3 vs. 4.8 ± 0.1 mg/(kg–min),
P
= 0.01]. This marked improvement in insulin-stimulated peripheral insulin responsiveness occurred independently of changes in plasma concentrations of TNF-α, IL-6, total adiponectin, C-reactive protein, acylcarnitines, and branched-chain amino acids. In conclusion, these data support the hypothesis that IMCL accumulation plays an important role in causing muscle insulin resistance in young, lean IR offspring, and that both are reversible with modest weight loss.
Resident CD141 (BDCA3)+ dendritic cells in human skin produce IL-10 and induce regulatory T cells that suppress skin inflammation
Authors: Chu Chung-Ching , Ali Niwa , Karagiannis Panagiotis , Di Meglio Paola , Skowera Ania , Napolitano Luca , Barinaga Guillermo , Grys Katarzyna , Sharif-Paghaleh Ehsan , Karagiannis Sophia N. , Peakman Mark , Lombardi Giovanna , Nestle Frank O.
Published: May 2012

Human skin immune homeostasis, and its regulation by specialized subsets of tissue-residing immune sentinels, is poorly understood. In this study, we identify an immunoregulatory tissue-resident dendritic cell (DC) in the dermis of human skin that is characterized by surface expression of CD141, CD14, and constitutive IL-10 secretion (CD141+ DDCs). CD141+ DDCs possess lymph node migratory capacity, induce T cell hyporesponsiveness, cross-present self-antigens to autoreactive T cells, and induce potent regulatory T cells that inhibit skin inflammation. Vitamin D3 (VitD3) promotes certain phenotypic and functional properties of tissue-resident CD141+ DDCs from human blood DCs. These CD141+ DDC-like cells can be generated in vitro and, once transferred in vivo, have the capacity to inhibit xeno-graft versus host disease and tumor alloimmunity. These findings suggest that CD141+ DDCs play an essential role in the maintenance of skin homeostasis and in the regulation of both systemic and tumor alloimmunity. Finally, VitD3-induced CD141+ DDC-like cells have potential clinical use for their capacity to induce immune tolerance.
easyFRAP: an interactive, easy-to-use tool for qualitative and quantitative analysis of FRAP data
Authors: Rapsomaniki Maria Anna , Kotsantis Panagiotis , Symeonidou Ioanna-Eleni , Giakoumakis Nickolaos-Nikiforos , Taraviras Stavros , Lygerou Zoi
Published: April 2012

Summary: We present easyFRAP, a versatile tool that assists quantitative and qualitative analysis of fluorescence recovery after photobleaching (FRAP) data. The user can handle simultaneously large data sets of raw data, visualize fluorescence recovery curves, exclude low quality data, perform data normalization, extract quantitative parameters, perform batch analysis and save the resulting data and figures for further use. Our tool is implemented as a single-screen Graphical User Interface (GUI) and is highly interactive, as it permits parameterization and visual data quality assessment at various points during the analysis.

Availability: easyFRAP is free software, available under the General Public License (GPL). Executable and source files, supplementary material and sample data sets can be downloaded at: ccl.med.upatras.gr/easyfrap.html.

Contact:  lygerou@med.upatras.gr; rapsoman@upatras.gr

Supplementary information:  Supplementary data are available at Bioinformatics online.
Optimal simultaneous superpositioning of multiple structures with missing data
Authors: Theobald Douglas L. , Steindel Phillip A.
Published: April 2012

Motivation: Superpositioning is an essential technique in structural biology that facilitates the comparison and analysis of conformational differences among topologically similar structures. Performing a superposition requires a one-to-one correspondence, or alignment, of the point sets in the different structures. However, in practice, some points are usually ‘missing’ from several structures, for example, when the alignment contains gaps. Current superposition methods deal with missing data simply by superpositioning a subset of points that are shared among all the structures. This practice is inefficient, as it ignores important data, and it fails to satisfy the common least-squares criterion. In the extreme, disregarding missing positions prohibits the calculation of a superposition altogether.

Results: Here, we present a general solution for determining an optimal superposition when some of the data are missing. We use the expectation–maximization algorithm, a classic statistical technique for dealing with incomplete data, to find both maximum-likelihood solutions and the optimal least-squares solution as a special case.

Availability and implementation: The methods presented here are implemented in THESEUS 2.0, a program for superpositioning macromolecular structures. ANSI C source code and selected compiled binaries for various computing platforms are freely available under the GNU open source license from http://www.theseus3d.org.

Contact:  dtheobald@brandeis.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Dehalococcoides mccartyi gen. nov., sp. nov., obligately organohalide-respiring anaerobic bacteria relevant to halogen cycling and bioremediation, belong to a novel bacterial class, Dehalococcoidia classis nov., order Dehalococcoidales ord. nov. and family Dehalococcoidaceae fam. nov., within the phylum Chloroflexi
Authors: Löffler Frank E. , Yan Jun , Ritalahti Kirsti M. , Adrian Lorenz , Edwards Elizabeth A. , Konstantinidis Konstantinos T. , Müller Jochen A. , Fullerton Heather , Zinder Stephen H. , Spormann Alfred M.
Published: April 2012

Six obligately anaerobic bacterial isolates (195T, CBDB1, BAV1, VS, FL2 and GT) with strictly organohalide-respiring metabolisms were obtained from chlorinated solvent-contaminated aquifers, contaminated and uncontaminated river sediments or anoxic digester sludge. Cells were non-motile with a disc-shaped morphology, 0.3–1 µm in diameter and 0.1–0.2 µm thick, and characteristic indentations on opposite flat sides of the cell. Growth occurred in completely synthetic, reduced medium amended with a haloorganic electron acceptor (mostly chlorinated but also some brominated compounds), hydrogen as electron donor, acetate as carbon source, and vitamins. No other growth-supporting redox couples were identified. Aqueous hydrogen consumption threshold concentrations were <1 nM. Growth ceased when vitamin B12was omitted from the medium. Addition of sterile cell-free supernatant ofDehalococcoides-containing enrichment cultures enhanced dechlorination and growth of strains 195 and FL2, suggesting the existence of so-far unidentified stimulants. Dechlorination occurred between pH 6.5 and 8.0 and over a temperature range of 15–35 °C, with an optimum growth temperature between 25 and 30 °C. The major phospholipid fatty acids were 14 : 0 (15.7 mol%), br15 : 0 (6.2 mol%), 16 : 0 (22.7 mol%), 10-methyl 16 : 0 (25.8 mol%) and 18 : 0 (16.6 mol%). Unusual furan fatty acids including 9-(5-pentyl-2-furyl)-nonanoate and 8-(5-hexyl-2-furyl)-octanoate were detected in strains FL2, BAV1 and GT, but not in strains 195Tand CBDB1. The 16S rRNA gene sequences of the six isolates shared more than 98 % identity, and phylogenetic analysis revealed an affiliation with the phylumChloroflexiand more than 10 % sequence divergence from other described isolates. The genome sizes and G+C contents ranged from 1.34 to 1.47 Mbp and 47 to 48.9 mol% G+C, respectively. Based on 16S rRNA gene sequence comparisons, genome-wide average nucleotide identity and phenotypic characteristics, the organohalide-respiring isolates represent a new genus and species, for which the nameDehalococcoides mccartyigen. nov., sp. nov. is proposed. Isolates BAV1 ( = ATCC BAA-2100  = JCM 16839  = KCTC 5957), FL2 ( = ATCC BAA-2098  = DSM 23585  = JCM 16840  = KCTC 5959), GT ( = ATCC BAA-2099  = JCM 16841  = KCTC 5958), CBDB1, 195T( = ATCC BAA-2266T = KCTC 15142T) and VS are considered strains ofDehalococcoides mccartyi, with strain 195Tas the type strain. The new classDehalococcoidiaclassis nov., orderDehalococcoidalesord. nov. and familyDehalococcoidaceaefam. nov. are described to accommodate the new taxon.
Algoriphagus chungangensis sp. nov., isolated from a tidal flat sediment
Authors: Kang Hyeonji , Weerawongwiwat Veeraya , Jung Min Young , Myung Soon Chul , Kim Wonyong
Published: April 2012

A Gram-stain-negative, non-spore-forming, non-motile, strictly aerobic, rod-shaped bacterial strain, designated CAU 1002T, was isolated from a tidal flat sediment and its taxonomic position was investigated using a polyphasic approach. Strain CAU 1002T grew optimally at 30 °C and pH 7.5. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CAU 1002T formed a distinct lineage within the genus

Algoriphagus

and was most closely related to

Algoriphagus lutimaris

KCTC 22630T and

Algoriphagus halophilus

KCTC 12051T (97.75 and 97.74 % 16S rRNA gene sequence similarity, respectively). The strain contained MK-7 as the major isoprenoid quinone and iso-C15 : 0 and C16 : 1ω7c and/or iso-C15 : 0 2-OH (summed feature 3) as the major fatty acids. The cell-wall peptidoglycan of strain CAU 1002T contained meso-diaminopimelic acids. The major whole-cell sugars were glucose, arabinose, sucrose, and ribose. The polar lipid profile was composed of phosphatidylethanolamine, five unidentified aminolipids, one unidentified aminophospholipid, one unidentified phospholipid, one unidentified aminoglycolipid, one unidentified glycolipid and twelve unidentified lipids. The DNA G+C content of strain CAU 1002T was 38.0 mol%. On the basis of phylogenetic inference, phenotypic, chemotaxonomic and genotypic data, strain CAU 1002T should be classified into the genus

Algoriphagus

as a member of a novel species, for which the name Algoriphagus chungangensis sp. nov. is proposed. The type strain is CAU 1002T ( = KCTC 23759T = CCUG 61890T). The description of the genus

Algoriphagus

is emended.
Chryseolinea serpens gen. nov., sp. nov., a member of the phylum

Bacteroidetes

isolated from soil
Authors: Kim Joong-Jae , Alkawally Mariam , Brady Allyson L. , Rijpstra W. Irene C. , Sinninghe Damsté Jaap S. , Dunfield Peter F.
Published: April 2012

An aerobic chemoheterotrophic gliding bacterium, designated RYGT, was isolated from a soil in Germany. Cells were Gram-stain-negative, thin rods (0.4–0.6 µm in width and 2.0–5.5 µm in length). Cells multiplied by normal cell division and no resting stages were observed. Colonies were yellow and displayed swarming edges. Gliding motility was observed in wet mounts. Strain RYGT grew at pH 5.6–7.7 (optimum pH 6.6–7.0), at 13–37 °C (optimum 25–30 °C) and with 0–1.0 % NaCl (optimum 0–0.1 %). The isolate was incapable of atmospheric nitrogen fixation and grew on most mono- and disaccharides as well as a few polysaccharides and organic acids. The predominant menaquinone was MK-7, the major cellular fatty acids were C16 : 1ω5c and iso-C15 : 0 and the major intact polar lipids were composed of phosphatidylethanolamine derivatives and two unknown series. The DNA G+C content was 49.9 mol%. Based on 16S rRNA gene sequence analysis, the isolate belonged to the phylum

Bacteroidetes

, class

Cytophagia

, order

Cytophagales

, but was only distantly related to any cultured bacteria. The closest relatives were

Ohtaekwangia koreensis

3B-2T and

Ohtaekwangia kribbensis

10AOT (both 93 % 16S rRNA gene sequence similarity). We propose a novel genus and species, Chryseolinea serpens gen. nov., sp. nov.. Strain RYGT ( = DSM 24574T = ATCC BAA-2075T) is the type strain.
Hymenobacter ginsengisoli sp. nov., isolated from soil of a ginseng field
Authors: Hoang Van-An , Kim Yeon-Ju , Nguyen Ngoc Lan , Yang Deok-Chun
Published: April 2012

A Gram-stain-negative, non-motile, red bacterium, designated DCY57T, was isolated from soil of a ginseng field in a mountainous region of Chungnam province in South Korea. Strain DCY57T grew with 0–1 % (w/v) NaCl and the optimum temperature for growth was 30 °C. Strain DCY57T contained MK-7 as the predominant menaquinone. The polyamine was sym-homospermidine. The major fatty acids were C16:1ω5c, iso-C15:0, anteiso-C15:0 and summed feature 3 (containing C16:1ω7c and/or C16:1ω6c). The major polar lipids were phosphatidylethanolamine, unknown aminophospholipids, unknown aminolipids and unknown lipids. The DNA G+C content was 58.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DCY57T was most closely related to members of the genus

Hymenobacter

. The isolate exhibited 91.7 % 16S rRNA gene sequence similarity with

H. soli

PB17T, 94.5 % with

H. flocculans

A2-50AT and 95.8 % with

H. metalli

A2-91T. On the basis of the evidence presented in this study, strain DCY57T represents a novel species within the genus

Hymenobacter

, for which the name Hymenobacter ginsengisoli sp. nov. is proposed. The type strain is DCY57T ( = KCTC 23674T = JCM 17841T).
Novosphingobium barchaimii sp. nov., isolated from hexachlorocyclohexane-contaminated soil
Authors: Niharika Neha , Moskalikova Hana , Kaur Jasvinder , Sedlackova Miroslava , Hampl Ales , Damborsky Jiri , Prokop Zbynek , Lal Rup
Published: April 2012

A yellow-pigmented bacterial strain, designated LL02T, was isolated from hexachlorocyclohexane-contaminated soil from Spolana Neratovice, a former Czech producer of lindane. A neighbour-joining tree based on 16S rRNA gene sequences showed that strain LL02T occupied a distinct phylogenetic position in the genus

Novosphingobium

and showed the highest sequence similarity with

Novosphingobium resinovorum

NCIMB 8767T (98.59 %). DNA–DNA relatedness between strain LL02T and its closest phylogenetic neighbours was <70 %, which indicated that strain LL02T represented a novel species of the genus

Novosphingobium

. The DNA G+C content of strain LL02T was 67.72±0 mol%. The major respiratory quinone was ubiquinone Q-10. The polar lipid profile of the isolate corresponded to those reported for other members of the genus

Novosphingobium

(phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylmonomethylethanolamine and sphingoglycolipids), thus supporting its classification in the genus. Spermidine was the major polyamine. The major fatty acids were summed feature 3 (consisting of C16 : 1ω7c and/or C16 : 1ω6c; 40.13 %), summed feature 8 (consisting of C18 : 1ω7c and/or C18 : 1ω6c; 31.09 %) and C14 : 0 2-OH (23.16 %). The results obtained from DNA–DNA hybridization and biochemical and physiological tests clearly distinguished the isolate from its closest phylogenetic neighbours. Thus, strain LL02T represents a novel species of the genus

Novosphingobium

, for which the name Novosphingobium barchaimii sp. nov. is proposed. The type strain is LL02T ( = CCM 7980T  = DSM 25411T).