bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge distribution on the surface of a dielectric barrier discharge actuator for the fluid-dynamic control
Authors: Cristofolini Andrea , Borghi Carlo A. , Neretti Gabriele
Published: April 2013

The electric potential distribution induced on the surface of an aerodynamic plasma actuator, operating by means of a surface dielectric barrier discharge (DBD), has been studied both numerically and experimentally. Three actuators made with three different dielectric materials (Teflon, Plexiglas, and glass) have been used. The geometric configuration of the three actuators is the same one. An electrode pair separated by a 2 mm thick dielectric sheet constitutes the DBD actuator. The exposed high voltage electrode has been fed by a 5 kHz a.c. electrical signal. Voltage values between 7.5 and 15 kVp have been used. Measurements of the distribution of the electrical potential in the dielectric surface, generated by the charge deposited on it, have been done. Numerical simulations allowed to evaluating the charge distribution on the dielectric surface. The discharge has been switched off after positive and negative plasma currents. The measurements have been carried out after both phases. The potential distribution is always positive. The charge build up takes place several centimeters downstream of the upper electrode for an extension broader than that of the plasma on the dielectric surface. The charge distribution strongly depends on the switching off phase and is heavily affected by the dielectric material. In order to evaluate the discharge structure and the extension of the plasma, images have been taken also.
A new magneto-elastic resonance based technique to determine magneto-mechanical parameters of amorphous ferromagnetic ribbons
Authors: Le Bras Y. , Lasheras A. , Gutierrez J. , Mazaleyrat F. , Greneche J. M.
Published: April 2013

Measurement of the magneto-mechanical parameters characteristics of amorphous ribbons often requires complex or limited methods due to their very small thickness. In this paper, it is shown how one can establish and estimate the characteristics of a magnetostrictive resonator from the experimental frequency response free of any kind of mechanical measurement (stress or elongation). This technique which is completely developed with a ribbon exhibiting good resonator properties, is suitable to estimate the magneto-mechanical coupling coefficient k33 and the Young's modulus and also to establish the magnetostriction curves λ(H) of amorphous ribbons. Results obtained from resonators made of 2605SC and 2826 from MetglasTM ribbons confirmed the validity of the present technique. However, measurements performed on a thin foil of nickel demonstrate that the present method cannot be extended to semi-soft magnetic materials. The technique which is proposed, has serious advantages upon others as it is non-destructive, low cost and easy to develop compared to common ones.
Growth and characterisation of Gd5(SixGe1−x)4 thin film
Authors: Hadimani R. L. , Nlebedim I. C. , Melikhov Y. , Jiles D. C.
Published: April 2013

We report for the first time successful growth of magnetic thin films containing the Gd5(SixGe1−x)4 phase, which is expected to show giant magnetocaloric properties. The film was deposited by Pulsed Laser Deposition (PLD) on a (001) silicon wafer at 200  °C from a polycrystalline Gd5Si2.09Ge1.91 target prepared by arc melting. PLD was achieved using a femto second laser with a repetition rate of 1 kHz, and a pulse energy of up to 3.5 mJ. The average film thickness was measured to be 400 nm using a Scanning Electron Microscopy and the composition of the film was analyzed using Energy Dispersive Spectroscopy and found to be close to the target composition. X-Ray Diffraction analysis confirmed the presence of Gd5Si2Ge2 monoclinic structure. Magnetic moment vs. magnetic field measurement confirmed that the film was ferromagnetic at a temperature of 200 K. The transition temperature of the film was determined from a plot of magnetic moment vs. temperature. The transition temperature was between 280 and 300 K which is close to the transition temperature of the bulk material.
Improved electrical properties of Ge metal-oxide-semiconductor devices with HfO2 gate dielectrics using an ultrathin GeSnOx film as the surface passivation layer
Authors: Zhao Mei , Liang Renrong , Wang Jing , Xu Jun
Published: April 2013

A surface passivation method for improving the interface quality of HfO2 gate dielectric on Ge substrate by using an ultrathin GeSnOx layer is reported. The GeSnOx layer is fabricated using a unique method. A GeSn layer is formed by sputtering Sn on Ge substrate and then removing the top Sn layer with diluted HCl solution. The ultrathin GeSn layer translates into the GeSnOx layer during thermal oxidation in an oxygen atmosphere. It is found that the electrical properties can be improved significantly for Ge/HfO2 devices with the introduction of a GeSnOx layer, including low midgap interface trap density and extremely low leakage current density of the gate stack.
Formation and ferromagnetic properties of FeSi thin films
Authors: Shin Yooleemi , Anh Tuan Duong , Hwang Younghun , Viet Cuong Tran , Cho Sunglae
Published: April 2013

In this work, the growth and ferromagnetic properties of ε-FeSi thin film on Si(100) substrate prepared by molecular beam epitaxy are reported. The inter-diffusion of Fe layer on Si(100) substrate at 600 °C results in polycrystalline ε-FeSi layer. The determined activation energy was 0.044 eV. The modified magnetism from paramagnetic in bulk to ferromagnetic states in ε-FeSi thin films was observed. The saturated magnetization and coercive field of ε-FeSi film are 4.6 emu/cm3 and 29 Oe at 300 K, respectively.
Thermoelectric transport for a quantum wire side-coupled to a graphene sheet between ferromagnetic leads
Authors: Zhou Benhu , Zhou Benliang , Zeng Aihua , Zhou Guanghui , Yang Fu-Bin
Published: April 2013

We theoretically investigate the thermoelectric transport through a quantum wire (QW) side-coupled by a graphene sheet and sandwiched between two ferromagnetic electrodes with noncollinear magnetic moments. By using the nonequilibrium Green's function combining with the tight-binding Hamiltonian, it is demonstrated that both the thermopower and the electronic contribution to the thermal conductance develop an oscillating behavior with resonances and antiresonances due to constructive and destructive interferences in the system, respectively. Interestingly, the thermopower changes its sign for even- or odd-number of atoms in the wire, and the thermal conductance is always positive with an even-odd behavior at zero energy level position of the quantum wire. Moreover, the thermopower and the thermal conductance are weakly dependent on the wire–graphene coupling strength as well as the relative magnetic configurations of leads. On the contrary, they are both strongly dependent on the temperature and the polarization strength of the leads. The results obtained here may provide a valuable theoretical guidance to experimentally design heat spintronic devices.
Ultra small mode volume defect cavities in spatially ordered and disordered metamaterials
Authors: Kaina Nadège , Lemoult Fabrice , Fink Mathias , Lerosey Geoffroy
Published: April 2013

In this letter, we study metamaterials made out of resonant electric wires arranged on a spatial scale much smaller than the free space wavelength, and we show that they present a hybridization band that is insensible to positional disorder. We experimentally demonstrate defect cavities in disordered and ordered samples and prove that, analogous to those designed in photonic crystals, those cavities can present very high quality factors. In addition, we show that they display mode volumes much smaller than a wavelength cube, owing to the deep subwavelength nature of the unit cell. We underline that this type of structure can be shrunk down to a period close of a few skin depth. Our approach paves the way towards the confinement and manipulation of waves at deep subwavelength scales in both ordered and disordered metamaterials.
Optimal design of the solar tracker used for a photovoltaic string
Authors: Alexandru Cătălin , Irina Tatu Nicoleta
Published: April 2013

This paper approaches the optimal design of the mono-axial tracking system used for a string of photovoltaic (PV) modules. The tracking mechanism is designed in a CAD (Computer Aided Design) environment (SolidWorks), the solid model being then transferred in the dynamic analysis and optimization environment (adams/View). The control system is designed with adams/Controls and matlab/Simulink, in mechatronic concept, by integrating the mechanical device and the control system at the virtual prototype level. The control method is based on a single-open-loop model with PID (Proportional-Integral-Derivative) controller, having as input the daily angle of the PV string. The output from the control system (i.e., the input in the mechanical device model) is the motor torque developed by the rotary actuator that drives the system. The tracking program has been developed by using an empirical model of the solar irradiation, obtaining the optimal angular field for the daily motion, the number of motion steps, and the actuating time. The optimization purpose is to minimize the tracking error, the design objective's value being the root mean square during simulation. The specific parameters of the PID controller are used as design variables in the optimization process. The investigation strategy is based on a design of experiments technique, obtaining the appropriate regression function. Finally, the physical prototype is developed and tested in real environment, the experimental results being used to validate the virtual prototyping-based simulation.
Theoretical performance study of a liquid desiccant regenerator supported with scavenging air heat exchanger
Authors: Kabeel A. E. , Bassuoni M. M.
Published: April 2013

This paper proposed a simplified theoretical model of the air and liquid desiccant parameters inside any packed bed liquid desiccant regenerator supported with scavenging air to air heat exchanger to reduce regeneration heat. The presented model depends mainly on the value of regenerator effectiveness regardless the packed bed structure type or the direction of flows inside the regenerator. Calcium chloride is used as desiccant material in this investigation. Both regenerator humidity and temperature effectiveness are applied for derivation of the numerical solution. The numerical solutions have showed good accuracy with a maximum deviation of 3.64% when compared with reliable experimental data available in the literature. The method developed here can be used in the quick prediction of the regenerator performance. The effects of variables such as air temperature and humidity, desiccant regeneration temperature, concentration, solution to air flow rate, and others on the regenerator performance have been investigated. The results reveal that operating variables such as desiccant concentration, desiccant regeneration temperature, and solution to air flow rate have the greatest impact on the performance of the regenerator. As a result of using scavenging air to air heat exchanger, the exit desiccant concentration increases by about 21.5% while the heat rate required for regeneration can be decreased by about 18% for the same exit concentration.
Switchable static friction of piezoelectric composite—silicon wafer contacts
Authors: van den Ende D. A. , Fischer H. R. , Groen W. A. , van der Zwaag S.
Published: April 2013

The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and a silicon wafer counter surface rests solely on the matrix region of the piezocomposite surface. When actuated, the piezoelectric ceramic fibers protrude from the surface and the wafer rests solely on these protrusions. A threefold decrease in engineering static friction coefficient upon actuation of the piezocomposite was observed: from μ* = 1.65 to μ* = 0.50. These experimental results could be linked to the change in contact surface area and roughness using capillary adhesion theory, which relates the adhesive force to the number and size of the contacting asperities for the different surface states.
Re-poling process for piezoelectric-based multilayer ceramic capacitors force sensor
Authors: Lin Keng-Ren , Chang Chih-Han , Chiang Cheng-Hung , Lin Che-Hsin
Published: April 2013

This study presents an industrial-grade piezoelectric-based multilayer ceramic capacitors (MLCCs) force sensor. In order to increase the sensitivity and reduce the variation of different MLCCs, a simple re-poling process is adopted by applying an external electric field at the Curie temperature of MLCCs. Results indicate that the re-poling treatment improved up to 100-fold for the force detection sensitivity and reduced the variation for the output force response by 10-fold in comparison with the MLCC sensors without re-poling.
Combined effects of nuclear and electronic energy losses in solids irradiated with a dual-ion beam
Authors: Thomé Lionel , Debelle Aurélien , Garrido Frédérico , Trocellier Patrick , Serruys Yves , Velisa Gihan , Miro Sandrine
Published: April 2013

Single and dual-beam irradiations of oxide (c-ZrO2, MgO, Gd2Ti2O7) and carbide (SiC) single crystals were performed to study combined effects of nuclear (Sn) and electronic (Se) energy losses. Rutherford backscattering experiments in channeling conditions show that the Sn/Se cooperation induces a strong decrease of the irradiation-induced damage in SiC and MgO and almost no effects in c-ZrO2 and Gd2Ti2O7. The healing process is ascribed to electronic excitations arising from the electronic energy loss of swift ions. These results present a strong interest for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where expected cooperative Sn/Se effects may lead to the preservation of the integrity of nuclear devices.
Introducing new design and performance points for photovoltaic water pumping systems based on long-term field data analysis
Authors: Odeh I.
Published: April 2013

Three years field data analysis for eight systems installed in Jordan is used to determine and investigate photovoltaic (PV), subsystems and system efficiencies of PV water pumping systems. For these three parameters, it is found that all systems inhibit unique trend with insolation. New performance points are determined, defined, and illustrated in this work to determine the effect of insolation on system performance and to use them in system design and optimization process. These points clearly indicate system performance, accuracy of its design, influence of external parameters on system operation and the need for further optimizations. These points can be used to find out the most optimum PV array size which eventually results in better economic feasibility of the whole system.
High-performance dye-sensitized solar cells containing double-layer organized mesoporous TiO2 films sensitized by a dye with a high molar extinction coefficient
Authors: Wang Juangang , Shang Yunli
Published: April 2013

In the present work, we describe a practical technique to construct double-layer organized mesoporous TiO2 films with a combined thickness of 0.85 μm. Large mesopores (25.74 nm) formed in the film by using ovalbumin as the main template facilitate entry and adsorption of dye molecules. The films were sensitized by a dye that exhibits a high molar extinction coefficient because it contains a ligand with a fused-ring system. The double-layer films exhibited a solar conversion efficiency of 7.37%, which was about 35% higher than that of monolayer films.
Evolution of extortion in Iterated Prisoner’s Dilemma games
Authors: Hilbe Christian , Nowak Martin A. , Sigmund Karl
Published: April 2013

Iterated games are a fundamental component of economic and evolutionary game theory. They describe situations where two players interact repeatedly and have the ability to use conditional strategies that depend on the outcome of previous interactions, thus allowing for reciprocation. Recently, a new class of strategies has been proposed, so-called “zero-determinant” strategies. These strategies enforce a fixed linear relationship between one’s own payoff and that of the other player. A subset of those strategies allows “extortioners” to ensure that any increase in one player’s own payoff exceeds that of the other player by a fixed percentage. Here, we analyze the evolutionary performance of this new class of strategies. We show that in reasonably large populations, they can act as catalysts for the evolution of cooperation, similar to tit-for-tat, but that they are not the stable outcome of natural selection. In very small populations, however, extortioners hold their ground. Extortion strategies do particularly well in coevolutionary arms races between two distinct populations. Significantly, they benefit the population that evolves at the slower rate, an example of the so-called “Red King” effect. This may affect the evolution of interactions between host species and their endosymbionts.
Turbulent shear spurs settlement in larval sea urchins
Authors: Gaylord Brian , Hodin Jason , Ferner Matthew C.
Published: April 2013

Marine invertebrates commonly produce larvae that disperse in ocean waters before settling into adult shoreline habitat. Chemical and other seafloor-associated cues often facilitate this latter transition. However, the range of effectiveness of such cues is limited to small spatial scales, creating challenges for larvae in finding suitable sites at which to settle, especially given that they may be carried many kilometers by currents during their planktonic phase. One possible solution is for larvae to use additional, broader-scale environmental signposts to first narrow their search to the general vicinity of a candidate settlement location. Here we demonstrate strong effects of just such a habitat-scale cue, one with the potential to signal larvae that they have arrived in appropriate coastal areas. Larvae of the purple sea urchin (
Strongylocentrotus purpuratus
) exhibit dramatic enhancement in settlement following stimulation by turbulent shear typical of wave-swept shores where adults of this species live. This response manifests in an unprecedented fashion relative to previously identified cues. Turbulent shear does not boost settlement by itself. Instead, it drives a marked developmental acceleration that causes “precompetent” larvae refractory to chemical settlement inducers to immediately become “competent” and thereby reactive to such inducers. These findings reveal an unrecognized ability of larval invertebrates to shift the trajectory of a major life history event in response to fluid-dynamic attributes of a target environment. Such an ability may improve performance and survival in marine organisms by encouraging completion of their life cycle in advantageous locations.
ApiAP2 transcription factor restricts development of the
Toxoplasma
tissue cyst
Authors: Radke Joshua B. , Lucas Olivier , De Silva Erandi K. , Ma YanFen , Sullivan William J. , Weiss Louis M. , Llinas Manuel , White Michael W.
Published: April 2013

Cellular differentiation leading to formation of the bradyzoite tissue cyst stage is the underlying cause of chronic toxoplasmosis. Consequently, mechanisms responsible for controlling development in the
Toxoplasma
intermediate life cycle have long been sought. Here, we identified 15
Toxoplasma
mRNAs induced in early bradyzoite development that encode proteins with apicomplexan AP2 (ApiAP2) DNA binding domains. Of these 15 mRNAs, the AP2IX-9 mRNA demonstrated the largest expression increase during alkaline-induced differentiation. At the protein level, we found that AP2IX-9 was restricted to the early bradyzoite nucleus and is repressed in tachyzoites and in mature bradyzoites from 30-d infected animals. Conditional overexpression of AP2IX-9 significantly reduced tissue cyst formation and conferred alkaline pH-resistant growth, whereas disruption of the
AP2IX-9
gene increased tissue cyst formation, indicating AP2IX-9 operates as a repressor of bradyzoite development. Consistent with a role as a repressor, AP2IX-9 specifically inhibited the expression of bradyzoite mRNAs, including the canonical bradyzoite marker, bradyzoite antigen 1 (BAG1). Using protein binding microarrays, we established the AP2 domain of AP2IX-9 binds a CAGTGT DNA sequence motif and is capable of binding
cis
-regulatory elements controlling the BAG1 and bradyzoite-specific nucleoside triphosphatase (B-NTPase) promoters. The effect of AP2IX-9 on BAG1 expression was direct because this factor inhibits expression of a firefly luciferase reporter under the control of the BAG1 promoter in vivo, and epitope-tagged AP2IX-9 can be immunoprecipitated with the BAG1 promoter in parasite chromatin. Altogether, these results indicate AP2IX-9 restricts
Toxoplasma
commitment to develop the mature bradyzoite tissue cyst.
Haunting Language-Game: Baudrillardian Metamorphoses in Sadeq Hedayat's The Blind Owl
Authors: Mansouri-Zeyni Sina
Published: April 2013

As an acclaimed work of twentieth-century Persian fiction, Sadeq Hedayat's The Blind Owl has stirred much scholarly contemplation. Identical characters obscure the work; the resemblance amongst them seemingly originates in some mysterious old man. The paper first demonstrates how every male character resembles this old man. Thereafter, he is argued to be non-existent; all the characters, therefore, become Baudrillardian simulacra bound together through family resemblances. A language-game is then fashioned to represent the family. The metamorphosis of the narrator is followed to manifest how this language-game haunts the characters—other language-games. The paper hopefully sheds some light on an ambiguous aspect of the work and provides a model as to how one language-game takes over another.
Relations Between Feeding Intolerance and Stress Biomarkers in Preterm Infants
Authors: Moore Tiffany A. , Wilson Margaret E. , Schmid Kendra K. , Anderson‐Berry Ann , French Jeffrey A. , Berger Ann M.
Published: April 2013

Objectives:

Feeding intolerance (FI) in preterm infants is common but the etiology remains unclear. This study examined FI as a stress‐related disease involving brain–gut interactions and tested the model of allostatic load and complications of prematurity. Specific aims were to describe demographic/medical variables and biomarker levels at each time and over time for the sample; describe/compare variables and biomarker levels at each time for infants with/without FI; and compare biomarker interquartile/interpercentile distributions between infants with/without FI.

Methods:

Preterm infants <32 weeks' gestation were recruited. The primary outcome was FI by day 7 defined as a feeding withheld, discontinued, or decreased because the infant was not tolerating enteral feedings. Allostatic load was operationalized using cortisol and 8‐hydroxydeoxyguanosine (8‐OHdG) from cord blood and from saliva and urine on days 1, 7, and 14. Descriptive statistics and comparative analyses were performed.

Results:

Seven of 31 infants enrolled met criteria for FI. Infants with FI had lower median urinary cortisol on day 1 (P = 0.007) and trended to have lower cortisol in the cord blood (P = 0.056). Interquartile distributions were significantly different between infants with/without FI for urinary cortisol on day 1 (P = 0.034) and trended for differences in 8‐OHdG on day 14 (P = 0.087). Interpercentile distributions were significantly different in salivary cortisol on day 14 (P = 0.034) and trended for differences in 8‐OHdG on day 1 (P = 0.079).

Conclusions:

Results support further testing of the model in a larger sample; investigation of the cellular mechanisms associated with the stress and the free radical/antioxidant systems; and inclusion of prenatal factors.
Human face structure correlates with professional baseball performance: insights from professional Japanese baseball players
Authors: Tsujimura Hikaru , Banissy Michael J.
Published: April 2013

In our daily lives, we use faces as a major source of information about other people. Recent work has begun to highlight how one's facial width-to-height ratio (fWHR) is linked to a number of behaviours (e.g. deception, aggression and financial performance in firms). fWHR has also been linked to several factors that may be beneficial for sport (e.g. achievement drive, winning mentality and aggression). Despite this, few studies have examined the relationship between fWHR and sports performance, and these have focused on Caucasian sportsmen. Here, we investigated the relationship between fWHR and baseball performance in professional Japanese baseball players. We show that fWHR is positively related with home run performance across two consecutive seasons. The findings provide the first evidence linking fWHR to baseball performance and linking fWHR to behavioural outcomes in Asian participants.
Low fertility of wild hybrid male flycatchers despite recent divergence
Authors: Ålund Murielle , Immler Simone , Rice Amber M. , Qvarnström Anna
Published: April 2013

Postzygotic isolation may be important for maintaining species boundaries, particularly when premating barriers are incomplete. Little is known about the course of events leading from minor environmental mismatches affecting hybrid fitness to severe genetic incompatibilities causing sterility or inviability. We investigated whether reduced reproductive success of hybrid males was caused by suboptimal sperm traits or by more severe genetic incompatibilities in a hybrid zone of pied (Ficedula hypoleuca) and collared flycatchers (F. albicollis) on the island of Öland, Sweden. About 4 per cent hybridization is observed in this population and all female hybrids are sterile. We found no sperm in the ejaculates of most sampled hybrid males, and sperm with abnormal morphology in two hybrids. Furthermore, none of the hybrids sired any offspring because of high levels of hatching failure and extra-pair paternity in their nests. These results from a natural hybrid zone suggest that the spermatogenesis of hybrid males may become disrupted despite little genetic divergence between the parental species.
Stress hormone receptors change as range expansion progresses in house sparrows
Authors: Liebl Andrea L. , Martin Lynn B.
Published: April 2013

As ranges expand, individuals encounter different environments at the periphery than at the centre of the range. Previously, we have shown that glucocorticoids (GCs) vary with range expansion: individuals at the range edge release more GCs in response to restraint. Here, we measured hippocampal mRNA expression of GC receptors (mineralocorticoid, MR and glucocorticoid, GR) in eight house sparrow (
Passer domesticus
) populations varying in age. We found that individuals closest to the range edge had the lowest expression of MR relative to GR; in all likelihood, this relationship was driven by a marginal reduction of MR mRNA at the range edge. Reduced MR (relative to GR) might allow enhanced GC binding to GR, the lower affinity receptor that would enhance a rapid physiological and behavioural response to stressors. The insights gained from this study are not only enlightening to introduced species, but may also predict how certain species will react as their ranges shift owing to anthropogenic changes.
Fritz Joseph Ursell. 28 April 1923 — 11 May 2012
Authors: Abrahams I. D. , Martin P. A.
Published: April 2013

Fritz Ursell was a singular and influential applied mathematician. He made seminal contributions to research in the mathematical analysis of linear water waves. This required the development of new techniques for the asymptotic evaluation of integrals, especially uniformly valid approximations. He made numerous contributions to the field; for example, he constructed a family of solutions for edge waves on a sloping beach that extended Stokes’s original result, he gave a detailed analysis of the Kelvin ship-wave pattern, and he was the first to prove the existence of trapped modes in water-wave problems.
Integrability of reductions of the discrete Korteweg–de Vries and potential Korteweg–de Vries equations
Authors: Hone A. N. W. , van der Kamp P. H. , Quispel G. R. W. , Tran D. T.
Published: April 2013

We study the integrability of mappings obtained as reductions of the discrete Korteweg–de Vries (KdV) equation and of two copies of the discrete potential KdV (pKdV) equation. We show that the mappings corresponding to the discrete KdV equation, which can be derived from the latter, are completely integrable in the Liouville–Arnold sense. The mappings associated with two copies of the pKdV equation are also shown to be integrable.
Genome-Wide Prediction of Nucleosome Occupancy in Maize Reveals Plant Chromatin Structural Features at Genes and Other Elements at Multiple Scales
Authors: Fincher Justin A. , Vera Daniel L. , Hughes Diana D. , McGinnis Karen M. , Dennis Jonathan H. , Bass Hank W.
Published: April 2013

The nucleosome is a fundamental structural and functional chromatin unit that affects nearly all DNA-templated events in eukaryotic genomes. It is also a biochemical substrate for higher order, cis-acting gene expression codes and the monomeric structural unit for chromatin packaging at multiple scales. To predict the nucleosome landscape of a model plant genome, we used a support vector machine computational algorithm trained on human chromatin to predict the nucleosome occupancy likelihood (NOL) across the maize (Zea mays) genome. Experimentally validated NOL plots provide a novel genomic annotation that highlights gene structures, repetitive elements, and chromosome-scale domains likely to reflect regional gene density. We established a new genome browser (http://www.genomaize.org) for viewing support vector machine-based NOL scores. This annotation provides sequence-based comprehensive coverage across the entire genome, including repetitive genomic regions typically excluded from experimental genomics data. We find that transposable elements often displayed family-specific NOL profiles that included distinct regions, especially near their termini, predicted to have strong affinities for nucleosomes. We examined transcription start site consensus NOL plots for maize gene sets and discovered that most maize genes display a typical +1 nucleosome positioning signal just downstream of the start site but not upstream. This overall lack of a –1 nucleosome positioning signal was also predicted by our method for Arabidopsis (Arabidopsis thaliana) genes and verified by additional analysis of previously published Arabidopsis MNase-Seq data, revealing a general feature of plant promoters. Our study advances plant chromatin research by defining the potential contribution of the DNA sequence to observed nucleosome positioning and provides an invariant baseline annotation against which other genomic data can be compared.
MERISTEM DISORGANIZATION1Encodes TEN1, an Essential Telomere Protein That Modulates Telomerase Processivity inArabidopsis
Authors: Leehy Katherine A. , Lee Jung Ro , Song Xiangyu , Renfrew Kyle B. , Shippen Dorothy E.
Published: April 2013

Telomeres protect chromosome ends from being recognized as DNA damage, and they facilitate the complete replication of linear chromosomes. CST [for CTC1(Cdc13)/STN1/TEN1] is a trimeric chromosome end binding complex implicated in both aspects of telomere function. Here, we characterize TEN1 in the flowering plant Arabidopsis thaliana. We report that TEN1 (for telomeric pathways in association with Stn1, which stands for suppressor of cdc thirteen) is encoded by a previously characterized gene, MERISTEM DISORGANIZATION1 (MDO1). A point mutation in MDO1, mdo1-1/ten1-3 (G77E), triggers stem cell differentiation and death as well as a constitutive DNA damage response. We provide biochemical and genetic evidence that ten1-3 is likely to be a null mutation. As with ctc1 and stn1 null mutants, telomere tracts in ten1-3 are shorter and more heterogeneous than the wild type. Mutants also exhibit frequent telomere fusions, increased single-strand telomeric DNA, and telomeric circles. However, unlike stn1 or ctc1 mutants, telomerase enzyme activity is elevated in ten1-3 mutants due to an increase in repeat addition processivity. In addition, TEN1 is detected at a significantly smaller fraction of telomeres than CTC1. These data indicate that TEN1 is critical for telomere stability and also plays an unexpected role in modulating telomerase enzyme activity.
Telomerase-Dependent 3′ G-Strand Overhang Maintenance Facilitates GTBP1-Mediated Telomere Protection from Misplaced Homologous Recombination
Authors: Lee Yong Woo , Kim Woo Taek
Published: April 2013

At the 3′-end of telomeres, single-stranded G-overhang telomeric repeats form a stable T-loop. Many studies have focused on the mechanisms that generate and regulate the length of telomere 3′ G-strand overhangs, but the roles of G-strand overhang length control in proper T-loop formation and end protection remain unclear. Here, we examined functional relationships between the single-stranded telomere binding protein GTBP1 and G-strand overhang lengths maintained by telomerase in tobacco (Nicotiana tabacum). In tobacco plants, telomerase reverse transcriptase subunit (TERT) repression severely worsened the GTBP1 knockdown phenotypes, which were formally characterized as an outcome of telomere destabilization. TERT downregulation shortened the telomere 3′ G-overhangs and increased telomere recombinational aberrations in GTBP1-suppressed plants. Correlatively, GTBP1-mediated inhibition of single-strand invasion into the double-strand telomeric sequences was impaired due to shorter single-stranded telomeres. Moreover, TERT/GTBP1 double knockdown amplified misplaced homologous recombination of G-strand overhangs into intertelomeric regions. Thus, proper G-overhang length maintenance is required to protect telomeres against intertelomeric recombination, which is achieved by the balanced functions of GTBP1 and telomerase activity.
Semi-maleate salts ofL- andDL-serinium: the first example of chiral and racemic serinium salts with the same composition and stoichiometry
Authors: Arkhipov Sergey G. , Zakharov Boris A. , Boldyreva Elena V.
Published: April 2013

L-Serinium semi-maleate, (I), and DL-serinium semi-maleate, (II), both C3H8NO3+·C4H3O4−, provide the first example of chiral and racemic anhydrous serine salts with the same organic anion. A comparison of their crystal structures with each other, with the structures of the pure components (L-serine polymorphs, DL-serine and maleic acid) and with other amino acid maleates is important for understanding the formation of the crystal structures, their response to variations in temperature and pressure, and structure–property relationships. As in other known crystal structures of amino acid maleates, there are no direct links between the semi-maleate anions in the two new structures. The serinium cations have different conformations in (I) and (II). In (I), they are linked into infinite chainsviahydrogen bonds between carboxylic acid and hydroxy groups. In (II), there are no such chains formed by the serinium cations. In both (I) and (II), there areC22(12) chains consisting of alternating semi-maleate anions and serinium cations. Two types of such chains are present in (I) and (II), termedC22(12) andC22(12)′. In (I), these chains, lying in the same plane, are further linked to each otherviahydrogen bonds, whereas in (II) they are not.
A square-pyramidal copper(II) complex with strong intramolecular hydrogen bonds: diaqua(N,N′-dimethylformamide-κO)bis[2-(diphenylphosphoryl)benzoato-κO]copper(II)
Authors: Zhou Mengbo , Song Li , Niu Feng , Shu Kangying , Chai Wenxiang
Published: April 2013

In the title CuIIcomplex, [Cu(C19H14O3P)2(C3H7NO)(H2O)2], the molecule is bisected by a twofold axis relating the two 2-(diphenylphosphoryl)benzoate (ODPPB) ligands. The asymmetric unit consists of a CuIImetal centre on the symmetry axis, an ODPPB ligand, one water ligand and one dimethylformamide (DMF) ligand (disordered around the twofold axis). The CuIIion has fivefold coordination provided by two carboxylate O atoms from two ODPPB ligands, two O atoms from two coordinated water molecules and another O atom from a (disordered) DMF molecule, giving a CuO5square-pyramidal coordination geometry. The ODPPB ligand adopts a terminal monocoordinated mode with two free O atoms forming two strong intramolecular hydrogen bonds with the coordinated water molecules, which may play a key role in the stability of the molecular structure, as shown by the higher release temperature for the coordinated water molecules than for the coordinated DMF molecule. The optical absorption properties of powder samples of the title compound have also been studied.
A one-dimensionalABX3-type coordination polymer:catena-poly[benzyltrimethylammonium [tri-μ-chlorido-cadmium(II)]]
Authors: Wu De-Hong , Jin Lei
Published: April 2013

The crystal structure of the title novel one-dimensionalABX3-type organic–inorganic hybrid complex {(C10H16N)[CdCl3]}n, (I), consists of benzyltrimethylammonium (Me3BzN+) cations and one-dimensional anionic {[Cd(μ-Cl)3]−}∞chains. Each CdIIcentre is hexacoordinated by bridging chloride ligands, giving a slightly distorted octahedral Cd(μ-Cl)6arrangement. The octahedra are linked by two opposite shared faces, giving rise to an almost perfectly linear anionic {[Cd(μ-Cl)3]−}∞chain in thea-axis direction. Me3BzN+cations located in the inter-chain spaces balance the charge. Noncovalent static attracting forces (Coulombic and van der Waals forces) and nonclassical C—H...Cl hydrogen-bond interactions stabilize the crystal structure.
The influence of geomorphology on the role of women at artisanal and small‐scale mine sites
Authors: Malpeli Katherine C. , Chirico Peter G.
Published: April 2013

The geologic and geomorphic expressions of a mineral deposit determine its location, size, and accessibility, characteristics which in turn greatly influence the success of artisans mining the deposit. Despite this critical information, which can be garnered through studying the surficial physical expression of a deposit, the geologic and geomorphic sciences have been largely overlooked in artisanal mining‐related research. This study demonstrates that a correlation exists between the roles of female miners at artisanal diamond and gold mining sites in western and central Africa and the physical expression of the deposits. Typically, women perform ore processing and ancillary roles at mine sites. On occasion, however, women participate in the extraction process itself. Women were found to participate in the extraction of ore only when a deposit had a thin overburden layer, thus rendering the mineralized ore more accessible. When deposits required a significant degree of manual labour to access the ore due to thick overburden layers, women were typically relegated to other roles. The identification of this link encourages the establishment of an alternative research avenue in which the physical and social sciences merge to better inform policymakers, so that the most appropriate artisanal mining assistance programs can be developed and implemented.
Antimicrobial Effects of Vapor Phase Thymol, Modified Atmosphere, and Their Combination against Salmonella spp. on Raw Shrimp
Authors: Zhou Siyuan , Sheen Shiowshuh , Pang Yu‐Hsin , Liu LinShu , Yam Kit L.
Published: April 2013

Salmonella contamination on raw shrimp is a big food safety concern in the United States currently. This research evaluated the inhibition effects of vapor phase thymol, modified atmosphere (MA), and their combination against Salmonella spp. on raw shrimp. Growth profiles of a Salmonella spp. cocktail (6 strains), inoculated onto the surface of raw shrimp, treated with vapor phase thymol at 3 levels (0, 0.8, and 1.6 mg/L), or MA (59.5% CO2 + 39.5% N2 + 1% O2), both alone and in combination, at 3 temperatures (8, 12, and 16 ºC), were determined. Lag time and maximum growth rate of Salmonella spp. under each treatment were obtained using Baranyi and Roberts models. Results indicated that both vapor phase thymol and MA treatments alone inhibited the growth potential of Salmonella spp. effectively, extending the lag time by 10% to 100% and reducing the maximum growth rate by 14% to 71% compared with controlled samples at experimental temperatures (8, 12, and 16 ºC). Combination treatments of vapor phase thymol and MA exhibited greater inhibition effectiveness than each individual treatment and a synergistic antimicrobial effectiveness could be observed on the lag time extension. To the maximum, at 12 ºC, lag time of Salmonella spp. was extended 59.6% more by the combination treatment of 0.8 mg/L thymol + MA (36.97 h) than those effects combined from 0.8 mg/L thymol treatment and MA treatment alone (23.16 h in total). This combination strategy could be potentially utilized for Salmonella inhibition during the long distance and temperature‐abused raw shrimp import process.

Practical Application The vapor phase thymol + MA combination strategy could be potentially applied in temperature‐abused and long‐distance raw shrimp import process to retard the Salmonella spp. growth, therefore reducing its import rejection rate as well as enhancing its food safety level to the consumers’ concerns.
Selection of Yeasts as Starter Cultures for Table Olives
Authors: Bevilacqua Antonio , Beneduce Luciano , Sinigaglia Milena , Corbo Maria Rosaria
Published: April 2013

Ninety‐nine yeasts were isolated from Bella di Cerignola table olives; first, the strains were studied in relation to their ability to produce biogenic amines in a laboratory medium and 49 strains were positive to this assay and cut off from the research. The remaining 50 strains were characterized for their enzymatic traits (β‐glucosidase, catalase, pectolytic, xylanolytic, and lipolytic activities) and for their ability to grow at different temperatures, pHs, with salt or lactic/acetic acids added. Data were used for the evaluation of growth index and submitted to cluster and principal component analyses to choose the most promising 4 strains. In the final step of the research, the strains were inoculated as a cocktail in a model brine, containing different amounts of salt (4% to 12%) and glucose (0% to 3%), and adjusted to different pHs (4.0 to 9.0). Data analysis through a multiple regression procedure highlighted that salt, glucose, and pH acted in a different way within the storage and NaCl affected yeast growth only for few days, and then glucose and pH played a major role.

Practical Application Olive fermentation relies upon a complex microflora, including lactic acid bacteria and yeasts; the selection of suitable strains of yeasts intended as starter cultures, as well as their inoculation in brines, could improve the fermentation.
Increased hepcidin expression in non‐small cell lung cancer tissue and serum is associated with clinical stage
Authors: Chen Qian , Wang Li , Ma Yuchao , Wu Xianning , Jin Longyu , Yu Fenglei
Published: April 2013

Background

Hepcidin is a small secreted peptide that plays a key role in iron metabolism. A high level of hepcidin expression may be implicated in colorectal cancer; however, the relationship between hepcidin and lung cancer has not yet been studied.

Methods

Serum hepcidin‐25, bone morphogenetic protein (BMP)‐2, and interleukin (IL)‐6 concentration in 53 patients and 16 non‐cancerous individuals was measured by enzyme‐linked immune sorbent assay. Reverse transcriptase quantitative polymerase chain reaction (RT‐qPCR) was utilized to study the expression of hepcidin mRNA in paired tumor and non‐tumor lung tissues in surgical specimens from 65 patients with non small cell lung cancer (NSCLC), as well as in six types of lung cancer cell lines and human bronchial epithelial (HBE) cells. Hepcidin protein expression and cellular localization in NSCLC was determined by immunohistochemistry.

Results

The serum hepcidin‐25 concentration was higher in patients with NSCLC than in non‐cancerous individuals, and was positively correlated with serum BMP2 concentration, but negatively with serum IL‐6 levels. Serum hepcidin was also correlated with lymph node metastasis and clinical stage. Hepcidin mRNA expression was higher in cancerous tissues of NSCLC than in normal pulmonary tissues (P = 0.001). Hepcidin mRNA levels in four lung carcinoma cell lines were higher than in HBE cells. Immunohistochemistry showed that hepcidin protein was increased in cancerous tissues of NSCLC.

Conclusions

The level of hepcidin expression increased in NSCLC tissue and serum. Serum hepcidin‐25 level was associated with lymph node metastasis and tumor clinical stage in patients with NSCLC.
Estimating the effect of temporally autocorrelated environments on the demography of density‐independent age‐structured populations
Authors: Engen Steinar , Sæther Bernt‐Erik , Armitage Kenneth B. , Blumstein Daniel T. , Clutton‐Brock Tim H. , Dobson F. Stephen , Festa‐Bianchet Marco , Oli Madan K. , Ozgul Arpat
Published: April 2013

In age‐structured populations, environmental autocorrelations influence the long‐run population growth rate as well as the variance in future population size. We used the concept of individual reproductive value to examine how autocorrelated environments affect the dynamics of age‐structured populations, leading to transparent interpretations and estimation of these effects.

Environmental autocorrelation is expressed by the covariances between mean individual reproductive values for each age class and size of the same age class with stochastic components depending only on noise matrices from previous years. Thus, if an age class that is large in a given year also tends to perform better than the temporal average of that class in the contribution per individual to future population sizes, then the environmental autocorrelation will be positive.

We use a simple model with temporal autocorrelation in recruitment rate to illustrate the theory through analytical results as well as stochastic simulations. We show how the effect of environmental autocorrelation, the term included in the long‐run growth rate, as well as influencing the variance of future population size, can be estimated using a combination of individual‐based demographic data and time series of fluctuations in age composition without estimating autocorrelations and cross‐correlations of large numbers of age‐specific vital rates.

The method was applied to data from four mammal species. These analyses revealed that the influence of autocorrelations in the environmental noise on the dynamics of these species was small and in two populations almost negligible.

The theoretical explorations as well as the empirical estimates indicate that the temporal scaling of the environmental autocorrelation must be long to substantially affect the long‐term population growth rate. The white noise approximation is therefore often very accurate.
TEN‐like eruption in setting of EBV positive T‐cell lymphoproliferative disease with HLH, in a child
Authors: Sharma Niyati , Clark Jonathan , Pham Hiep , Efron Daryl , MacGregor Duncan , O'Keefe Rodney , Orchard David
Published: April 2013

Haemophagocytic lymphohistiocytosis complicating Epstein–Barr virus positive T‐cell lymphoproliferative disease of childhood is a rare and life‐threatening entity. We report a child with this condition presenting with a toxic epidermal necrolysis‐like eruption.