bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolutionary relationships in Oxytropis species, as estimated from the nuclear ribosomal internal transcribed spacer (ITS) sequences point to multiple expansions into the Arctic
Authors: Archambault Annie , Strömvik Martina V.
Published: August 2012

Species of the genus Oxytropis are distributed in the northern hemisphere, especially in alpine and arctic areas. Although comprehensive taxonomic treatments exist for local floras, an understanding of the evolutionary relationships is lacking for the genus as a whole. To determine if different ancestral Oxytropis species colonized the North American Arctic separately, as suggested by taxonomy, we sequenced the nuclear ribosomal internal transcribed spacer (ITS) region from 16 Oxytropis specimens, including four species that were used in a previous transcriptome study. In addition, 81 other Oxytropis ITS sequences were retrieved from public sequence databases and included in the analysis. The whole data set was analyzed using phylogenetic trees and statistical parsimony networks. Results show that all Oxytropis ITS sequences are very similar. Furthermore, at least six lineages evolved from different temperate ancestors to colonize the North American Arctic. This pattern is believed to be typical of the arctic flora. Additionally, the sequence relationship analyses confirm that the subgenus Phacoxytropis may be ancestral in Oxytropis.
Tiller organization within the tussock grass Schizachyrium scoparium: a field assessment of competition–cooperation tradeoffs
Authors: Derner Justin D. , Briske David D. , Polley H. Wayne
Published: August 2012

Tussock grasses are characterized by a compact spatial arrangement of tillers that contributes to intense intratussock competition. This investigation was designed to directly assess the magnitude of competition among autonomous subunits of tillers within individual tussocks (i.e., integrated physiological units) to further define the mechanisms of tiller organization within this successful growth form. Experimentally constructed tussocks of Schizachyrium scoparium (Michx. Nash) were grown in the field in central Texas, USA, for 2 years with 1, 4, 8, or 12 autonomous subunits to span the range observed in naturally occurring local populations. Increasing numbers of subunits per tussock did not affect tiller density or the mean mass of individual vegetative or reproductive tillers, but it did intensify intratussock competition as evidenced by a large reduction in total tiller mass and number per subunit. This pattern of tiller organization is indicative of a division of labor within the tussock that is manifested as a tradeoff between competition among autonomous subunits and cooperation among tillers within these physiologically integrated subunits. We conclude that an increasing number of autonomous subunits associated with tussock basal expansion contributes to coarse-scale resource preemption and competitive ability, while resource sharing among tillers within subunits supports new tiller establishment and growth within this highly competitive microenvironment.
Drought-driven disturbance history characterizes a southern Rocky Mountain subalpine forest
Authors: DeRose R. Justin , Long James N.
Published: August 2012

The view that subalpine forest vegetation dynamics in western North America are “driven” by a particular disturbance type (i.e., fire) has shaped our understanding of their disturbance regimes. In the wake of a recent (1990s) landscape-extent spruce beetle ( Dendroctonus rufipennis Kirby) outbreak in the southern Rocky Mountains, we re-examined the temporal continuity in disturbance types and interactions and the possible role of drought on their occurrence by reconstructing antecedent disturbances for 11 sites across the Markagunt Plateau, southern Utah, USA. Multiple consistent lines of evidence suggested that historic fires were the primary antecedent disturbance, while relatively minor, stand-specific spruce beetle activity occurred later in stand development but prior to the recent outbreak. Unlike the recent outbreak, antecedent fires were spatially and temporally asynchronous over the period examined (~1600–2000). Reconstructed fire events primarily occurred during periods of prolonged drought. Similarly, historic spruce beetle activity, indicated by species-specific tree-ring release, and timing of Engelmann spruce ( Picea engelmannii Parry ex Engelm.) death dates from the recent outbreak were related to drought conditions. Vegetation dynamics on this landscape were strongly driven by historic fires and the recent spruce beetle outbreak, and drought conditions likely influenced the occurrence of both disturbance types.
Genetic improvement for pulpwood and peeled veneer inEucalyptus nitens
Authors: Blackburn David , Farrell Ross , Hamilton Matthew , Volker Peter , Harwood Chris , Williams Dean , Potts Brad
Published: August 2012

Genetic improvement of wood properties affecting the quality of pulpwood and peeled veneer products is of general interest to tree breeders worldwide. If the wood properties of Eucalyptus nitens (H. Deane & Maiden) Maiden are under genetic control and the correlations between them are favourable, it may be possible to breed to simultaneously improve the plantation resource for both products. Acoustic wave velocity (AWV) measured in standing trees can predict wood stiffness, basic density, and kraft pulp yield (KPY) and therefore has the potential for use in tree breeding programs. From an E. nitens progeny trial in Tasmania, 540 trees were selected for rotary peeling. Of the wood properties assessed, there were significant differences among races in diameter, stem straightness, standing-tree, log, and billet AWV, and near infrared predicted cellulose content (CC). All traits displayed significant within-race genetic variation, and genetic correlations between AWV and veneer sheet modulus of elasticity (MOE) and between AWV and KPY and CC were strongly positive and highly significant. A similar relationship was found between veneer sheet MOE and KPY and between diameter at breast height and veneer sheet MOE. Basic density was genetically correlated with AWV and veneer sheet MOE. Results indicate that it should be possible for breeders to simultaneously improve properties in pulpwood and peeled veneer products and that AWV measured in the standing tree shows promise as a breeding selection criterion for both pulpwood and peeled veneer products.
d-Propranolol protects against oxidative stress and progressive cardiac dysfunction in iron overloaded rats
Authors: Kramer Jay H. , Spurney Christopher F. , Iantorno Micaela , Tziros Constantine , Chmielinska Joanna J. , Mak I. Tong , Weglicki William B.
Published: August 2012

d-Propranolol (d-Pro: 2–8 mg·(kg body mass)–1·day–1) protected against cardiac dysfunction and oxidative stress during 3–5 weeks of iron overload (2 mg Fe–dextran·(g body mass)–1·week–1) in Sprague–Dawley rats. At 3 weeks, hearts were perfused in working mode to obtain baseline function; red blood cell glutathione, plasma 8-isoprostane, neutrophil basal superoxide production, lysosomal-derived plasma N-acetyl-β-galactosaminidase (NAGA) activity, ventricular iron content, and cardiac iron deposition were assessed. Hearts from the Fe-treated group of rats exhibited lower cardiac work (26%) and output (CO, 24%); end-diastolic pressure rose 1.8-fold. Further, glutathione levels increased 2-fold, isoprostane levels increased 2.5-fold, neutrophil superoxide increased 3-fold, NAGA increased 4-fold, ventricular Fe increased 4.9-fold; and substantial atrial and ventricular Fe-deposition occurred. d-Pro (8 mg) restored heart function to the control levels, protected against oxidative stress, and decreased cardiac Fe levels. After 5 weeks of Fe treatment, echocardiography revealed that the following were depressed: percent fractional shortening (%FS, 31% lower); left ventricular (LV) ejection fraction (LVEF, 17%), CO (25%); and aortic pressure maximum (Pmax, 24%). Mitral valve E/A declined by 18%, indicating diastolic dysfunction. Cardiac CD11b+ infiltrates were elevated. Low d-Pro (2 mg) provided modest protection, whereas 4–8 mg greatly improved LVEF (54%–75%), %FS (51%–81%), CO (43%–78%), Pmax(56%–100%), and E/A >100%; 8 mg decreased cardiac inflammation. Since d-Pro is an antioxidant and reduces cardiac Fe uptake as well as inflammation, these properties may preserve cardiac function during Fe overload.
Protective effects of dexrazoxane against acute ischaemia/reperfusion injury of rat hearts
Authors: Neckář Jan , Boudíková Adéla , Mandíková Petra , Štěrba Martin , Popelová Olga , Mikšík Ivan , Dabrowská Ludmila , Mráz Jaroslav , Geršl Vladimír , Kolář František
Published: August 2012

Dexrazoxane (DEX), an inhibitor of topoisomerase II and intracellular iron chelator, is believed to reduce the formation of reactive oxygen species (ROS) and protects the heart from the toxicity of anthracycline antineoplastics. As ROS also play a role in the pathogenesis of cardiac ischaemia/reperfusion (I/R) injury, the aim was to find out whether DEX can improve cardiac ischaemic tolerance. DEX in a dose of 50, 150, or 450 mg·(kg body mass)–1was administered intravenously to rats 60 min before ischaemia. Myocardial infarct size and ventricular arrhythmias were assessed in anaesthetized open-chest animals subjected to 20 min coronary artery occlusion and 3 h reperfusion. Arrhythmias induced by I/R were also assessed in isolated perfused hearts. Only the highest dose of DEX significantly reduced infarct size from 53.9% ± 4.7% of the area at risk in controls to 37.5% ± 4.3% without affecting the myocardial markers of oxidative stress. On the other hand, the significant protective effect against reperfusion arrhythmias occurred only in perfused hearts with the dose of DEX of 150 mg·kg–1, which also tended to limit the incidence of ischaemic arrhythmias. It is concluded that DEX in a narrow dose range can suppress arrhythmias in isolated hearts subjected to I/R, while a higher dose is needed to limit myocardial infarct size in open-chest rats.
Cardiorespiratory and metabolic responses associated with children’s physical activity during self-paced games
Authors: Belcastro Angelo N. , Morrison Katherine S. , Hicks Emma , Matta Helin
Published: August 2012

The aim of this study was to explore the possibility of identifying clusters of children’s games based on estimated energy expenditures and (or) intensity when performed in a guided active play format. The study also investigated whether the identified active play game clusters were repeatable when the games were performed on different days. Children (9.7 ± 1.1 years; n = 12) were assessed for oxygen consumption, heart rate, energy expenditure (EE), and metabolic equivalent (MET) on a treadmill (at 4, 6, and 8 km·h–1(0% grade)). HR and ActiGraph GT1M accelerometer (ACC) generated linear regression equations were used to estimate EE. The ACC (3 s epochs) were used for estimating METs in assigning percent time at medium–vigorous physical activity (%MVPA) of 10 self-paced games. The results showed a consistent range of EEs (ACC-equation) from 13.57 kcal·(5 min)–1to 25.00 kcal·(5 min)–1(p < 0.05); EEs (HR-equation) from 29.72 to 42.49 kcal·(5 min)–1(p < 0.05); and %MVPA from 10% to 34% (p < 0.05) (from ACC equations) across all games. These were reproducible from day to day (p > 0.05). This study confirms the existence of active play children’s game clusters that might be useful in formatting guided active play in a dose–response manner for children.
Metabolic syndrome: a brain disease
Authors: Singh Ram B. , Gupta Siddharth , Dherange Parinita , De Meester Fabien , Wilczynska Agnieszka , Alam Shaan E. , Pella Daniel , Wilson Douglas W.
Published: August 2012

Recent research indicates an association between brain dysfunction and the pathogenesis of metabolic syndrome. To investigate this, we created a Medline search (up to December 2011) of articles in PubMed. The results indicated that refined carbohydrates, saturated and total fat, high levels of ω-6 fatty acids, and low levels of ω-3 fatty acids and other long chain polyunsaturated fatty acids (PUFA), all in conjunction with sedentary behaviour and mental stress can predispose to inflammation. Increased sympathetic activity, with increased secretion of catecholamine, cortisol, and serotonin can cause oxidative stress, which may damage the arcuate nucleus as well as the hypothalamus and macrophages, and the liver may release pro-inflammatory cytokines. These, in conjunction with an underlying deficiency in long chain PUFA, may damage the arcuate nucleus as well as neuropeptide-Y and pro-opiomelanocortin neurons and insulin receptors in the brain, especially during fetal life, infancy, and childhood, resulting in their dysfunction. Of the fatty acids in the brain, 30%–50% are long chain PUFA, which are incorporated in the cell membrane phospholipids. Hence, ω-3 fatty acids, which are also known to enhance parasympathetic activity and increase the secretion of anti-inflammatory cytokines interleukin (IL)-4 and IL-10 as well as acetylcholine in the hippocampus, may be protective. Therefore, treatment with ω-3 fatty acids may be applied for the prevention of metabolic syndrome.
Triacylglyceride (TAG) profiles of integumentary lipids isolated from three bat species determined by matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI–TOF MS)
Authors: Pannkuk E.L. , Gilmore D.F. , Savary B.J. , Risch T.S.
Published: August 2012

Lipids secreted from sebaceous glands in bat integument may play a role in determining host pathogenicity by the fungus Geomyces destructans in white-nose syndrome (WNS). To investigate this, we have determined the triacylglycerol (TAG) profiles for three bat species: eastern red bats ( Lasiurus borealis (Müller, 1776)), evening bats ( Nycticeius humeralis (Rafinesque, 1818)), and big brown bats ( Eptesicus fuscus (Beauvois, 1796)). Neutral lipids extracted from the hair and wing tissue were fractionated by preparative thin-layer chromatography (TLC) into four major lipid bands corresponding to cholesterol, free fatty acids (FFAs), TAGs, and sterol–wax esters. Densitometry showed higher proportions of TAGs in hair than from wing tissue. TAG bands were recovered and analyzed by matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI–TOF MS). Mass spectra showed sodiated TAG species with variable fatty acyl (FA) moieties range from m/z 715.6–911.8. High intensity ion peaks were consistent with 16:0 and 18:1 as dominant FA moieties, and these were identified as palmitic and oleic acids, respectively, by liquid chromatography electrospray ionization mass spectrometry. We determined significant differences in TAG profiles between three bat species by MALDI–TOF MS, providing the first description of integumentary lipids in bats. In this study, we performed the first TAG profiling of bats, which suggest such profiles may be species-specific in bats.
Natural and anthropogenic substrates affect movement behavior of the Southern Graycheek Salamander (Plethodon metcalfi)
Authors: Semlitsch R.D. , Ecrement S. , Fuller A. , Hammer K. , Howard J. , Krager C. , Mozeley J. , Ogle J. , Shipman N. , Speier J. , Walker M. , Walters B.
Published: August 2012

Movement behavior is a critical process that interacts with landscape structure to affect population connectivity and persistence in fragmented or altered landscapes. The purpose of our study was to test whether different substrates (forest litter, soil, grass, gravel, and asphalt) found in fragmented forested landscapes affected the movement behavior of the Southern Graycheek Salamander (Plethodon metcalfi Brimley, 1912). Latency period of the salamanders was highest on grass substrate and significantly lower only on soil substrate. Sinuosity of the movement path of salamanders was lowest and contained more turns in grass and was significantly higher than only gravel and asphalt substrates. Velocity of the salamanders was highest on asphalt substrate but was not different from gravel substrate. Velocity was higher on asphalt than on grass, forest, or soil, and velocity was higher on gravel than on grass substrate. The results indicated that P. metcalfi reacted differently to natural and anthropogenic substrates, and we suggest that these behavioral differences could have both positive and negative implications for movement success and habitat resistance in forested landscapes fragmented by roads and development.
Parasite infection and host dynamics in a naturally fluctuating rodent population
Authors: Winternitz J.C. , Yabsley M.J. , Altizer S.M.
Published: August 2012

Parasites can both influence and be affected by host population dynamics, and a growing number of case studies support a role for parasites in causing or amplifying host population cycles. In this study, we examined individual and population predictors of gastrointestinal parasitism on wild cyclic montane voles ( Microtus montanus (Peale, 1848)) to determine if evidence was consistent with theory implicating parasites in population cycles. We sampled three sites in central Colorado for the duration of a multiannual cycle and recorded the prevalence and intensity of directly transmitted Eimeria Schneider, 1875 and indirectly transmitted cestodes from a total of 267 voles. We found significant associations between host infection status, individual traits (sex, age, and reproductive status) and population variables (site, trapping period, and population density), including a positive association between host density and cestode prevalence, and a negative association between host density and Eimeria prevalence. Both cestode and Eimeria intensity correlated positively with host age, reproductive status, and population density, but neither parasite was associated with poorer host condition. Our findings suggest that parasites are common in this natural host, but determining their potential to influence montane vole cycles requires future experimental studies and long-term monitoring to determine the fitness consequences of infection and the impact of parasite removal on host dynamics.
GENERIC QUANTUM MARKOV SEMIGROUPS, CYCLE DECOMPOSITION AND DEVIATION FROM EQUILIBRIUM
Authors: FAGNOLA FRANCO , UMANITÀ VERONICA
Published: August 2012

A generic quantum Markov semigroup [Formula: see text] of a d-level quantum open system with a faithful normal invariant state ρ admits a dual semigroup [Formula: see text] with respect to the scalar product induced by ρ. We show that the difference of the generators [Formula: see text] can be written as the sum of a derivation 2i[H, ⋅] and a weighted difference of automorphisms [Formula: see text] where [Formula: see text] is a family of cycles on the d levels of the system, wc are positive weights and [Formula: see text] are unitaries.

This formula allows us to represent the deviation from equilibrium (in a "small" time interval) as the superposition of cycles of the system where the difference between the forward and backward evolution is written as the difference of a reversible evolution and its time reversal. Moreover, it generalises cycle decomposition of Markov jump processes.

We also find a similar formula with partial isometries instead of unitaries.
A NEW LOOK AT THE ARCSINE LAW AND "QUANTUM-CLASSICAL CORRESPONDENCE"
Authors: SAIGO HAYATO
Published: August 2012

We prove that the arcsine law as the time-averaged distribution for classical harmonic oscillators emerges from the distributions for quantum harmonic oscillators in terms of noncommutative algebraic probability. This is nothing but a simple and rigorous realization of "Quantum-Classical Correspondence" for harmonic oscillators.
WEAK CONVERGENCE FOR QUASILINEAR STOCHASTIC HEAT EQUATION DRIVEN BY A FRACTIONAL NOISE WITH HURST PARAMETER H ∈ (½, 1)
Authors: EL MELLALI TARIK , OUKNINE YOUSSEF
Published: August 2012

In this paper, we consider a quasi-linear stochastic heat equation in one dimension on [0, 1], with Dirichlet boundary conditions driven by an additive fractional white noise. We formally replace the random perturbation by a family of noisy inputs depending on a parameter n ∈ ℕ which can approximate the fractional noise in some sense. Then, we provide sufficient conditions ensuring that the real-valued mild solution of the SPDE perturbed by this family of noises converges in law, in the space [Formula: see text] of continuous functions, to the solution of the fractional noise driven SPDE.
3-LIE MULTIPLIERS ON BANACH 3-LIE ALGEBRAS
Authors: GORDJI M. ESHAGHI , FAZELI A. , PARK CHOONKIL
Published: August 2012

In this paper, we study the space of 3-Lie multipliers on Banach 3-Lie algebras. Moreover, we investigate a characterization of 3-Lie multipliers on commutative and without order Banach 3-Lie algebras. Finally, we establish the stability and superstability of 3-Lie multipliers.
EXPANDING THE NOTION OF ENTREPRENEURSHIP CAPITAL IN AMERICAN COUNTIES: A PANEL DATA ANALYSIS 2002–07
Authors: PC CHANG ERICK , MISRA KAUSTAV , MEMILI ESRA
Published: August 2012

Entrepreneurship capital refers to the factors of a region that drives new businesses (Audretsch and Keilbach, 2004). This study considers industry growth and performance in manufacturing, retail and service as components of entrepreneurship capital to drive the long-term growth of new establishments. Using a panel data of 2,940 counties from 2002–2007, our results support the notion that the overall new venture activity is benefited by the industry growth and performance. Future research directions and practical implications are also discussed.
TARGETING THE POOR VERSUS FINANCIAL SUSTAINABILITY AND EXTERNAL FUNDING: EVIDENCE OF MICROFINANCE INSTITUTIONS IN GHANA
Authors: ANNIM SAMUEL KOBINA
Published: August 2012

This study tests the hypotheses that: (i) formal microfinance institutions (MFIs) using their own mobilized financial resources (based on owners' equity, commercial lending or deposits) for on-lending reach non-poor clients and (ii) concentrating on the achievement of financial sustainability causes an institution to target non-poor clients. Using data on 2,691 MFI clients and non-clients from Ghana, we revisit the microfinance argument of serving poorer clients and sustainability, and in addition examine the effect of the source of funds and type of institution on the financial and social objectives of MFIs. Following the correction of endogeneity, our regression analysis shows that unlike financial self-sufficiency, MFIs that are only operationally self-sufficient reach poorer clients, and also, formal institutions dispensing their own funds target non-poor clients. The latter finding suggests the importance of complementary development strategies and a deliberate harmonization of microfinance interventions, irrespective of the source of funds.
HIGHLY CATALYTICALLY ACTIVE PALLADIUM NANOPARTICLES INCORPORATED INSIDE METAL-ORGANIC FRAMEWORK PORES BY DOUBLE SOLVENTS METHOD
Authors: YADAV MAHENDRA , AIJAZ ARSHAD , XU QIANG
Published: August 2012

Highly monodispersed palladium (Pd) nanoparticles have been successfully incorporated inside the mesopores of a metal–organic framework (MOF), MIL-101, without deposition of Pd nanoparticles on the external surfaces of framework by using the "double solvents" method, in which cyclohexane is used as a hydrophobic solvent to disperse the mesoporous MOF and an aqueous solution of Pd precursor is used as a hydrophilic solvent to fill the mesopores. The resulting Pd @MIL-101 composite is highly catalytically active for the reduction of 4-nitrophenol (4-NPh) by sodium borohydride ( NaBH4 ). The observed excellent catalytic performances are attributed to the small Pd nanoparticles within the pores of MIL-101.
PZT FILM GENERATOR DRIVEN BY ULTRASONIC WAVE
Authors: ZHOU QIFA , LAM KWOK HO , ZHU BENPENG , ZHANG XIABING , SHUNG K. KIRK , YANG TONGQING , TAKEUCHI S.
Published: August 2012

Energy harvesting was demonstrated in hydrothermal PZT nanocrystal films driven by ultrasound. With high temperature sintering and solution infiltration, PZT films with nanograin size was found to exhibit bulk-like properties such as large remnant polarization of 42 μC/cm2. With the bulk-like properties, a packaged PZT film device was demonstrated to be capable of converting mechanical energy carried by the ultrasonic wave into electrical energy in a reliable and efficient way. The result suggests an alternative potential solution for energy harvesting application.
MORPHOTROPIC PHASE BOUNDARY AND DIELECTRIC RELAXATION STUDY OF (Bi0.5Na0.5)TiO3–BaTiO3 LEAD-FREE CERAMIC
Authors: PARIJA B. , PANIGRAHI S. , BADAPANDA T. , SINHA T. P.
Published: August 2012

We report the temperature and frequency dependence impedance spectroscopy of (1 - x) ( Bi 0.5 Na 0.5) TiO 3-x BaTiO 3 (abbreviated as BNT–BT) ceramics with 0 ≤ x ≤ 0.07 prepared by conventional solid-state route. X-ray diffraction analysis indicated that a solid solution is formed when BaTiO3 diffuses into the (Bi0.5Na0.5)TiO3 lattice and a morphotropic phase boundary between rhombohedral and tetragonal locates at x = 0.07. The microstructure indicated that the grain size reduces and the shape changes from rectangular to quasi-spherical with increase in BaTiO3 content. Complex Impedance Spectroscopy analysis suggested the presence of temperature-dependent relaxation process in the materials. The modulus mechanism indicated the non-Debye type of conductivity relaxation in the materials, which is supported by impedance data. The activation energies have been calculated from impedance, electric modulus studies and dc conductivity which suggests that the conductions are ionic in nature. The activation energy increases with increase of BT content up to x = 0.05 and decreases at x = 0.07 which also indicates the presence of morphotropic phase boundary at x = 0.07.
EFFECT OF IMPURITIES ON THE DIELECTRIC PROPERTIES OF OLEIC ACID
Authors: DE SOUSA F. F. , FREIRE P. T. C. , FILHO J. MENDES , OLIVEIRA A. C. , LONGHINOTTI E. , DE VASCONCELOS P. H. M. , SARAIVA G. D. , MOREIRA S. G. C. , ALCANTARA P.
Published: August 2012

Temperature dependence of the dielectric constant of oleic acid with different degrees of purity was measured in the 233–313 K range. It was observed that the presence of impurities (palmitic and linolenic acids) strongly influences the dielectric constant, melting point and dipole moment of the oleic acid. The values of apparent dipole moment and the Kirkwood correlation parameters were evaluated using the Kirkwood's model and were estimated to be about 1.20, 1.61 and 2.27 D, respectively for 60, 90 and 97 wt% oleic acid.
Epitaxial Lateral Overgrowth of Diamonds on Iridium by Patterned Nucleation and Growth Method
Authors: Ando Yutaka , Kamano Takashi , Suzuki Kazuhiro , Sawabe Atsuhito
Published: August 2012

Epitaxial lateral overgrowth (ELO) of diamond on Ir(001)/MgO(001) substrates was demonstrated by using a patterned nucleation and growth method. Epitaxial nucleation areas of fine line shape aligned with various crystal orientations were prepared on an Ir(001) surface before diamond growth. The growth rate of the diamonds in the lateral direction markedly changed depending on both the crystal orientation and the growth conditions. A lateral/vertical growth rate ratio of approximately 4.9 was obtained. The full widths at half maximum of the diamond Raman peak observed at the laterally grown areas were approximately threefold better than that of the vertically grown areas on the nucleation sites.
Highly Spin-Polarized Tunneling in Epitaxial Magnetic Tunnel Junctions with a Co2MnSi Electrode and a MgO Barrier with Improved Interfacial Structural Properties
Authors: Liu Hong-xi , Honda Yusuke , Matsuda Ken-ichi , Arita Masashi , Uemura Tetsuya , Yamamoto Masafumi
Published: August 2012

Fully epitaxial magnetic tunnel junctions (MTJs) with a Heusler alloy Co2MnSi electrode and a MgO barrier were prepared on MgO-buffered MgO(001) substrates with various layer structures to elucidate the contribution of coherent tunneling to the spin-dependent tunneling characteristics of these MTJs, which potentially feature both the half-metallicity of Co2MnSi and coherent tunneling. MTJs consisting of (from the lower side) Co50Fe50(CoFe)/MgO/Co2MnSi or CoFe-buffered Co2MnSi/MgO/CoFe showed almost identical, high tunnel magnetoresistance (TMR) ratios of 335% at 290 K (1049% at 4.2 K) and 340% at 290 K (879% at 4.2 K), respectively. In contrast, MTJs consisting of MgO-buffered Co2MnSi/MgO/CoFe showed a lower TMR ratio of 173% at 290 K (448% at 4.2 K). The higher TMR ratios obtained for CoFe/MgO/Co2MnSi MTJs and CoFe-buffered Co2MnSi/MgO/CoFe MTJs can be ascribed to the enhanced contribution of coherent tunneling that originated from decreased misfit dislocation densities at the lower and upper interfaces with a MgO barrier.
Improving Mobility of F-Doped SnO2 Thin Films by Introducing Temperature Gradient during Low-Pressure Chemical Vapor Deposition
Authors: Isshiki Masanobu , Ikeda Toru , Okubo Junichi , Oyama Takuji , Shidoji Eiji , Odaka Hidefumi , Sichanugrist Porponth , Konagai Makoto
Published: August 2012

High mobility is required to suppress free-carrier absorption in the near-infrared (NIR) region. Toward this end, we investigated the properties of a F-doped SnO2 (FTO) film deposited using low-pressure chemical vapor deposition (LPCVD) and found that the optimum deposition temperature varied with film thickness. On the basis of this result, we introduced a temperature gradient into LPCVD, which resulted in an improvement in the mobility of F-doped SnO2 on glass to 77.5 cm2 V-1 s-1.
One Dimensional Modeling of Radio Frequency Electric Field Penetration into Magnetized Plasmas
Authors: Matsuoka Takeshi , Rudenko Timofei S. , Funaki Ikkoh , Shamrai Konstantin P. , Nakamura Takahiro , Nishida Hiroyuki , Tanikawa Takao , Hada Tohru , Shinohara Shunjiro
Published: August 2012

Full penetration of RF electric fields into magnetized plasmas is expected in order to realize the Lissajous helicon plasma accelerator (LHPA). We study the electric field penetration in bulk plasma in one-dimensional electrostatic approximation using two analytical models: the matrix sheath model and the vacuum gap model. An identical formula for the electric field is obtained from the models. The formula is benchmarked by particle-in-cell (PIC) simulations. The full penetration of the electric field is realized when the relation (q ≪0.01) is satisfied, where q is the measure of the degree of the shielding effect due to plasma density and electron magnetization.
Architecture of rifted continental margins and break-up evolution: insights from the South Atlantic, North Atlantic and Red Sea–Gulf of Aden conjugate margins
Authors: Mohriak Webster Ueipass , Leroy Sylvie
Published: August 2012

The tectonosedimentary development of the South Atlantic is compared with the Central Atlantic margins, which are associated with major episodes of magmatism during the Mesozoic continental break-up. Subsequently, the Cenozoic break-up in the North Atlantic led to the formation of the volcanic Norwegian–Greenland conjugate margins. The DSDP boreholes in the magma-poor Iberian–Newfoundland margins have confirmed the occurrence of exhumed mantle at the ocean–continent transition. This possibility has been suggested for the South Atlantic margins, but still lacks confirmation from drilling.

The Red Sea and the Gulf of Aden may be considered as natural laboratories to study the break-up processes and formation of divergent continental margins. Using key geological and geophysical data, we compare some of the structures observed in incipient stages of basin formation between the African and the Arabian plates with the structures observed in older sedimentary basins associated with the Gondwana break-up. We also analyse deep seismic reflection profiles and potential field data at the continent–ocean boundary of these conjugate margins, using palinspastic reconstructions to define the corresponding seismic pairs. We conclude that the Red Sea and the Gulf of Aden display remarkable differences to the Iberian–Newfoundland margins, and notable similarities with the South Atlantic margins.
End-member modelling as an aid to diagnose remagnetization: a brief review
Authors: Dekkers Mark J.
Published: August 2012

Remagnetization of a palaeomagnetic signal is difficult to recognize independently of directional information. The situation becomes more complex when remagnetized rocks pass palaeomagnetic field tests, for example when the remagnetization of a rock sequence has occurred before folding. It is evident that palaeogeographic reconstructions are seriously flawed when actually remagnetized rocks are not identified as such. Here we discuss the merits and pitfalls of so-called end-member modelling of acquisition curves of the isothermal remanent magnetization (IRM) to recognize remagnetized strata. The technique requires no
a priori
information about the IRM acquisition curves. The algorithm unmixes a set of IRM acquisition curves into a number of invariant curves termed end members and calculates the mixing proportions of the end members for each sample. Since primary natural remanent magnetization (NRM) and remagnetized NRM are acquired by different processes, their signatures can be recognized from subtle differences in the magnetic properties. We illustrate the potential of the approach by three case studies, one from Spain and two from Turkey, in which the magnetic properties of remagnetized and non-remagnetized rocks are evaluated.
Mechanisms and Evolution of Virulence in Oomycetes
Authors: Jiang Rays H.Y. , Tyler Brett M.
Published: August 2012

Many destructive diseases of plants and animals are caused by oomycetes, a group of eukaryotic pathogens important to agricultural, ornamental, and natural ecosystems. Understanding the mechanisms underlying oomycete virulence and the genomic processes by which those mechanisms rapidly evolve is essential to developing effective long-term control measures for oomycete diseases. Several common mechanisms underlying oomycete virulence, including protein toxins and cell-entering effectors, have emerged from comparing oomycetes with different genome characteristics, parasitic lifestyles, and host ranges. Oomycete genomes display a strongly bipartite organization in which conserved housekeeping genes are concentrated in syntenic gene-rich blocks, whereas virulence genes are dispersed into highly dynamic, repeat-rich regions. There is also evidence that key virulence genes have been acquired by horizontal transfer from other eukaryotic and prokaryotic species.
Suppressive Composts: Microbial Ecology Links Between Abiotic Environments and Healthy Plants
Authors: Hadar Yitzhak , Papadopoulou Kalliope K.
Published: August 2012

Suppressive compost provides an environment in which plant disease development is reduced, even in the presence of a pathogen and a susceptible host. Despite the numerous positive reports, its practical application is still limited. The main reason for this is the lack of reliable prediction and quality control tools for evaluation of the level and specificity of the suppression effect. Plant disease suppression is the direct result of the activity of consortia of antagonistic microorganisms that naturally recolonize the compost during the cooling phase of the process. Thus, it is imperative to increase the level of understanding of compost microbial ecology and population dynamics. This may lead to the development of an ecological theory for complex ecosystems as well as favor the establishment of hypothesis-driven studies.
Loss of MLK3 signaling impedes ulcer healing by modulating MAPK signaling in mouse intestinal mucosa
Authors: Kovalenko Pavlo L. , Kunovska Lyudmyla , Chen Jian , Gallo Kathleen A. , Basson Marc D.
Published: August 2012

Mixed-lineage kinase 3 (MLK3) activates multiple MAPK pathways and can initiate apoptosis, proliferation, migration, or differentiation in different cell types. However, whether MLK3 signaling regulates intestinal epithelial cell sheet migration in vivo is not known. We sought to investigate whether MLK3 signaling is important in intestinal mucosal healing and epithelial cell motility in vivo and in vitro. In vivo, we compared the healing of jejunal mucosal ulcers induced in MLK3 knockout (KO) mice with healing in wild-type (WT) mice. Ulcer healing was 20.8% less at day 3 ( P < 0.05) and 18.9% less at day 5 ( P < 0.05) in MLK3 KO than WT mice. Within the intestinal mucosa of MLK3 KO mice, ERK and JNK signaling were reduced, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) level was increased, and p38 signaling was unchanged. Parallel in vitro studies using an MLK inhibitor assessed the role of MLK signaling in human Caco-2 intestinal epithelial migration across collagen substrates. The MLK inhibitor reduced closure of circular wounds in Caco-2 monolayers. MLK inhibition reduced ERK and JNK, but not p38, signaling in Caco-2 cells. Although PTEN is increased after MLK inhibition, it does not influence MLK-mediated cell migration. These findings indicate that disruption of MLK3 signaling impairs ulcer healing by suppressing ERK and JNK signaling in vitro and in mouse intestinal mucosa in vivo. These results reveal a novel role for MLK3 signaling in the regulation of intestinal epithelial migration in vivo and suggest that MLK3 may be an important target for the regulation of intestinal mucosal healing.
Leptin signaling in the nucleus of the solitary tract alters the cardiovascular responses to activation of the chemoreceptor reflex
Authors: Ciriello John , Moreau Jason M.
Published: August 2012

Circulating levels of leptin are elevated in individuals suffering from chronic intermittent hypoxia (CIH). Systemic and central administration of leptin elicits increases in sympathetic nervous activity (SNA), arterial pressure (AP), and heart rate (HR), and it attenuates the baroreceptor reflex, cardiovascular responses that are similar to those observed during CIH as a result of activation of chemoreceptors by the systemic hypoxia. Therefore, experiments were done in anesthetized Wistar rats to investigate the effects of leptin in nucleus of the solitary tract (NTS) on AP and HR responses, and renal SNA (RSNA) responses during activation of NTS neurons and the chemoreceptor reflex. Microinjection of leptin (5–100 ng; 20 nl) into caudal NTS pressor sites (l-glutamate; l-Glu; 0.25 M; 10 nl) elicited dose-related increases in AP, HR, and RSNA. Leptin microinjections (5 ng; 20 nl) into these sites potentiated the increase in AP and HR elicited by l-Glu. Additionally, bilateral injections of leptin (5 ng; 100 nl) into NTS potentiated the increase in AP and attenuated the bradycardia to systemic activation of the chemoreflex. In the Zucker obese rat, leptin injections into NTS neither elicited cardiovascular responses nor altered the cardiovascular responses to activation of the chemoreflex. Taken together, these data indicate that leptin exerts a modulatory effect on neuronal circuits within NTS that control cardiovascular responses elicited during the reflex activation of arterial chemoreceptors and suggest that increased AP and SNA observed in individuals with CIH may be due, in part, by leptin's effects on the chemoreflex at the level of NTS.
Sex differences in cardiorespiratory transition and surfactant composition following preterm birth in sheep
Authors: Ishak Noreen , Hanita Takushi , Sozo Foula , Maritz Gert , Harding Richard , De Matteo Robert
Published: August 2012

Male preterm infants are at greater risk of respiratory morbidity and mortality than females but mechanisms are poorly understood. Our objective was to identify the basis for the “male disadvantage” following preterm birth using an ovine model of preterm birth in which survival of females is greater than males. At 0.85 of term, fetal sheep underwent surgery (11 female, 10 male) for the implantation of vascular catheters to monitor blood gases and arterial pressure. After cesarean delivery at 0.90 of term, lambs were monitored for 4 h while spontaneously breathing; lambs were then euthanized and static lung compliance measured. We analyzed surfactant phospholipid composition in amniotic fluid and in bronchoalveolar lavage fluid (BALF) taken at necropsy; we also analyzed surfactant protein ( SP) expression in lung tissue. Before delivery male fetuses tended to have lower pH ( P = 0.052) compared with females. One hour after delivery, males had significantly lower pH and higher arterial partial pressure of CO2(PaCO2), lactate, glucose, and mean arterial pressure than females. Two males died 1 h after birth. Static lung compliance was 37% lower in males than females ( P < 0.05). In BALF, males had significantly more protein, a lower percentage of the phosphatidylcholine (PC) 32:0 (dipalmitoylphosphatidylcholine) and higher percentages of PC34:2 and PC36:2. There were no sex-related differences in lung architecture or expression of SP-A, -B, -C, and -D. The lower lung compliance in male preterm lambs compared with females may be due to altered surfactant phospholipid composition and function. These changes may compromise gas exchange and impair respiratory adaptation after male preterm birth.
Differences in oxidative stress status and expression of MKP-1 in dorsal medulla of transgenic rats with altered brain renin-angiotensin system
Authors: Nautiyal Manisha , Katakam Prasad V. G. , Busija David W. , Gallagher Patricia E. , Tallant E. Ann , Chappell Mark C. , Diz Debra I.
Published: August 2012

ANG II-stimulated production of reactive oxygen species (ROS) through NADPH oxidase is suggested to activate MAPK pathways, which are implicated in neurally mediated pressor effects of ANG II. Emerging evidence suggests that ANG-(1–7) up regulates MAPK phosphatases to reduce MAPK signaling and attenuate actions of ANG II. Whether angiotensin peptides participate in long-term regulation of these systems in the brain is not known. Therefore, we determined tissue and mitochondrial ROS, as well as expression and activity of MAPK phosphatase-1 (MKP-1) in brain dorsal medullary tissue of hypertensive transgenic (mRen2)27 rats exhibiting higher ANG II/ANG-(1–7) tone or hypotensive transgenic rats with targeted decreased glial expression of angiotensinogen, ASrAOGEN (AS) exhibiting lower ANG II/ANG-(1–7) tone compared with normotensive Sprague-Dawley (SD) rats that serve as the control strain. Transgenic (mRen2)27 rats showed higher medullary tissue NADPH oxidase activity and dihydroethidium fluorescence in isolated mitochondria vs. SD or AS rats. Mitochondrial uncoupling protein 2 was lower in AS and unchanged in (mRen2)27 compared with SD rats. MKP-1 mRNA and protein expression were higher in AS and unchanged in (mRen2)27 compared with SD rats. AS rats also had lower phosphorylated ERK1/2 and JNK consistent with higher MKP-1 activity. Thus, an altered brain renin-angiotensin system influences oxidative stress status and regulates MKP-1 expression. However, there is a dissociation between these effects and the hemodynamic profiles. Higher ROS was associated with hypertension in (mRen2)27 and normal MKP-1, whereas the higher MKP-1 was associated with hypotension in AS, where ROS was normal relative to SD rats.
Target organ cross talk in cardiorenal syndrome: animal models
Authors: Bongartz Lennart G. , Braam Branko , Gaillard Carlo A. , Cramer Maarten J. , Goldschmeding Roel , Verhaar Marianne C. , Doevendans Pieter A. , Joles Jaap A.
Published: August 2012

The combination of chronic kidney disease (CKD) and heart failure (HF) is associated with an adverse prognosis. Although clinical studies hint at a specific bidirectional interaction between HF and CKD, insight into the pathogenesis of cardiorenal syndrome (CRS) remains limited. We review available evidence on cardiorenal interactions from animal models of CKD and HF and discuss several studies that employed a “double-hit” model to research organ cross talk between the heart and kidneys. Regarding cardiac changes in CKD models, parameters of cardiac remodeling are equivocal and cardiac systolic function generally remains preserved. Structural changes include hypertrophy, fibrosis, and microvasculopathy. In models of HF, data on renal pathology are mostly limited to functional hemodynamic changes. Most double-hit models were unable to show that combined renal and cardiac injury induces additive damage to both organs, perhaps because of the short study duration or absence of organ failure. Because of this lack of “dual-failure” models, we have developed two rat models of combined CKD and HF in which renal dysfunction induced by a subtotal nephrectomy preceded cardiac dysfunction. Cardiac dysfunction was induced either functionally by nitric oxide depletion or structurally by myocardial infarction. In both models, we found that cardiac remodeling and failure were worse in CKD rats compared with controls undergoing the same cardiac insult. Variables of renal damage, like glomerulosclerosis and proteinuria, were also further worsened by combined cardiorenal injury. These studies show that target organ cross talk does occur in CRS. These models may be useful for interventional studies in rats.
Stroke volume-to-wall stress ratio as a load-adjusted and stiffness-adjusted indicator of ventricular systolic performance in chronic loading
Authors: Chemaly Elie R. , Chaanine Antoine H. , Sakata Susumu , Hajjar Roger J.
Published: August 2012

Load-adjusted measures of left ventricle (LV) systolic performance are limited by dependence on LV stiffness and afterload. To our knowledge, no stiffness-adjusted and afterload-adjusted indicator was tested in models of pressure (POH) and volume overload hypertrophy (VOH). We hypothesized that wall stress reflects changes in loading, incorporating chamber stiffness and afterload; therefore, stroke volume-to-wall stress ratio more accurately reflects systolic performance. We used rat models of POH (ascending aortic banding) and VOH (aorto-cava shunt). Animals underwent echocardiography and pressure-volume analysis at baseline and dobutamine challenge. We achieved extreme bidirectional alterations in LV systolic performance, end-systolic elastance (Ees), passive stiffness, and arterial elastance (Ea). In POH with LV dilatation and failure, some load-independent indicators of systolic performance remained elevated compared with controls, while some others failed to decrease with wide variability. In VOH, most, but not all indicators, including LV ejection fraction, were significantly reduced compared with controls, despite hyperdynamic circulation, lack of heart failure, and preserved contractile reserve. We related systolic performance to Ees adjusted for Ea and LV passive stiffness in multivariate models. Calculated residual Ees was not reduced in POH with heart failure and was reduced in VOH, while it positively correlated to dobutamine dose. Conversely, stroke volume-to-wall stress ratio was normal in compensated POH, markedly decreased in POH with heart failure, and, in contrast with LV ejection fraction, normal in VOH. Our results support stroke volume-to-wall stress ratio as a load-adjusted and stiffness-adjusted indicator of systolic function in models of POH and VOH.