Reduced mechanical efficiency in left-ventricular trabeculae of the spontaneously hypertensive rat.

Long-term systemic arterial hypertension, and its associated compensatory response of left-ventricular hypertrophy, is fatal. This disease leads to cardiac failure and culminates in death. The spontaneously hypertensive rat (SHR) is an excellent animal model for studying this pathology, suffering from ventricular failure beginning at about 18 months of age. In this study, we isolated left-ventricular trabeculae from SHR-F hearts and contrasted their mechanoenergetic performance with those from nonfailing SHR (SHR-NF) and normotensive Wistar rats. Our results show that, whereas the performance of the SHR-F differed little from that of the SHR-NF, both SHR groups performed less stress-length work than that of Wistar trabeculae. Their lower work output arose from reduced ability to produce sufficient force and shortening. Neither their heat production nor their enthalpy output (the sum of work and heat), particularly the energy cost of Ca(2+) cycling, differed from that of the Wistar controls. Consequently, mechanical efficiency (the ratio of work to change of enthalpy) of both SHR groups was lower than that of the Wistar trabeculae. Our data suggest that in hypertension-induced left-ventricular hypertrophy, the mechanical performance of the tissue is compromised such that myocardial efficiency is reduced

Effects of fluorine plasma and ammonia annealing on pentacene thin -film transistor with ZrLaOx as gate dielectric

Pentacene organic thin-film transistor (OTFT) based on ZrLaOx gate dielectric is proposed and has been fabricated. The effects of fluorine plasma and ammonia annealing on the properties of the OTFT have been studied. It reveals that the plasma treatment can greatly improve carrier mobility and shift the threshold voltage in the positive direction. With a threshold voltage less than 0.5 V, the OTFT can work at very low supply voltage. On the other hand, the ensuing ammonia annealing counteracts the plasma treatment and shifts the threshold voltage in the opposite direction. © 2012 IEEE.published_or_final_versio

High-Performance Pentacene Thin-Film Transistor With High-κ HfLaON as Gate Dielectric

published_or_final_versio

A low-frequency noise model with carrier generation-recombination process for pentacene organic thin-film transistor

published_or_final_versio

High-mobility pentacene OTFT with TaLaO gate dielectric passivated by fluorine plasma

Pentacene thin-film transistor with high-κ TaLaO as gate dielectric has been fabricated and shows a carrier mobility of 0.73 cm2/V s, much higher than that based on pure La2O3 (0.43 cm2/V s) due to the smoother surface of the TaLaO film and thus larger pentacene islands grown on it in the initial stage. Moreover, among various times for fluorine-plasma treatment on the TaLaO gate dielectric, 100 seconds result in the highest carrier mobility of 1.12 cm2/V s due to (1) smoothest oxide surface achieved by fluorine passivation of oxide traps, as measured by AFM and supported by smallest sub-threshold swing and lowest low-frequency noise; (2) the largest pentacene grains grown on the smoothest oxide surface, as demonstrated by AFM. Pentacene islands on on TaLaO or La2O3 gate dielectric with different plasma treatment times.postprin

Thermoelectric spin voltage in graphene

In recent years, new spin-dependent thermal effects have been discovered in ferromagnets, stimulating a growing interest in spin caloritronics, a field that exploits the interaction between spin and heat currents. Amongst the most intriguing phenomena is the spin Seebeck effect, in which a thermal gradient gives rise to spin currents that are detected through the inverse spin Hall effect. Non-magnetic materials such as graphene are also relevant for spin caloritronics, thanks to efficient spin transport, energy-dependent carrier mobility and unique density of states. Here, we propose and demonstrate that a carrier thermal gradient in a graphene lateral spin valve can lead to a large increase of the spin voltage near to the graphene charge neutrality point. Such an increase results from a thermoelectric spin voltage, which is analogous to the voltage in a thermocouple and that can be enhanced by the presence of hot carriers generated by an applied current. These results could prove crucial to drive graphene spintronic devices and, in particular, to sustain pure spin signals with thermal gradients and to tune the remote spin accumulation by varying the spin-injection bias

phyloXML: XML for evolutionary biology and comparative genomics

<p>Abstract</p> <p>Background</p> <p>Evolutionary trees are central to a wide range of biological studies. In many of these studies, tree nodes and branches need to be associated (or annotated) with various attributes. For example, in studies concerned with organismal relationships, tree nodes are associated with taxonomic names, whereas tree branches have lengths and oftentimes support values. Gene trees used in comparative genomics or phylogenomics are usually annotated with taxonomic information, genome-related data, such as gene names and functional annotations, as well as events such as gene duplications, speciations, or exon shufflings, combined with information related to the evolutionary tree itself. The data standards currently used for evolutionary trees have limited capacities to incorporate such annotations of different data types.</p> <p>Results</p> <p>We developed a XML language, named phyloXML, for describing evolutionary trees, as well as various associated data items. PhyloXML provides elements for commonly used items, such as branch lengths, support values, taxonomic names, and gene names and identifiers. By using "property" elements, phyloXML can be adapted to novel and unforeseen use cases. We also developed various software tools for reading, writing, conversion, and visualization of phyloXML formatted data.</p> <p>Conclusion</p> <p>PhyloXML is an XML language defined by a complete schema in XSD that allows storing and exchanging the structures of evolutionary trees as well as associated data. More information about phyloXML itself, the XSD schema, as well as tools implementing and supporting phyloXML, is available at <url>http://www.phyloxml.org</url>.</p

Estimating black hole masses of blazars

Estimating black hole masses of blazars is still a big challenge. Because of the contamination of jets, using the previously suggested size -- continuum luminosity relation can overestimate the broad line region (BLR) size and black hole mass for radio-loud AGNs, including blazars. We propose a new relation between the BLR size and $H_{\beta}$ emission line luminosity and present evidences for using it to get more accurate black hole masses of radio-loud AGNs. For extremely radio-loud AGNs such as blazars with weak/absent emission lines, we suggest to use the fundamental plane relation of their elliptical host galaxies to estimate the central velocity dispersions and black hole masses, if their velocity dispersions are not known but the host galaxies can be mapped. The black hole masses of some well-known blazars, such as OJ 287, AO 0235+164 and 3C 66B, are obtained using these two methods and the M - $\sigma$ relation. The implications of their black hole masses on other related studies are also discussed.Comment: 7 pages, invited talk presented in the workshop on Multiwavelength Variability of Blazars (Guangzhou, China, Sept. 22-24, 2010). To be published in the Journal of Astrophysics and Astronom