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 ZrLaO gate dielectric passivated by fluorine incorporation

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

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

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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

High-mobility pentacene thin-film transistor by using LaxTa(1-x)Oy as gate dielectric

Pentacene organic thin-film transistors (OTFTs) using LaxTa(1−x)Oy as gate dielectric with different La contents (x = 0.227, 0.562, 0.764, 0.883) have been fabricated and compared with those using Ta oxide or La oxide. The OTFT with La0.764Ta0.236Oy can achieve a carrier mobility of 1.21 cm2 V−1s−1s, which is about 40 times and two times higher than those of the devices using Ta oxide and La oxide, respectively. As supported by XPS, AFM and noise measurement, the reasons lie in that La incorporation can suppress the formation of oxygen vacancies in Ta oxide, and Ta content can alleviate the hygroscopicity of La oxide, resulting in more passivated and smoother dielectric surface and thus larger pentacene grains, which lead to higher carrier mobility.postprin

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

Pentacene organic thin-film transistor (OTFT) with high-K HffiO gate dielectric has been fabricated. The effects of fluorine plasma and ammonia annealing on the properties of the OTFT have been studied. After treating the dielectric in the plasma, the carrier mobility of the transistor can be improved by about 5 times to 0.0883 cm2/V•s. Moreover, the fluorine plasma treatment can shift the threshold voltage of the device in the positive direction. Experimental results also show that NH3 annealing can enhance the OTFT performance in terms of higher mobility, smaller sub-threshold slope and larger on/off ratio.published_or_final_versio

Estimation of breakout sound power level due to turbulence caused by an in-duct element

2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Sol-gel based materials for biomedical applications

Sol-gel chemistry offers a flexible approach to obtaining a diverse range of materials. It allows differing chemistries to be achieved as well as offering the ability to produce a wide range of nano-/micro-structures. The paper commences with a generalized description of the various sol-gel methods available and how these chemistries control the bulk properties of the end products. Following this, a more detailed description of the biomedical areas where sol-gel materials have been explored and found to hold significant potential. One of the interesting fields that has been developed recently relates to hybrid materials that utilize sol-gel chemistry to achieve unusual composite properties. Another intriguing feature of sol-gels is the unusual morphologies that are achievable at the micro- and nano-scale. Subsequently the ability to control pore chemistry at a number of different length scales and geometries has proven to be a fruitful area of exploitation, that provides excellent bioactivity and attracts cellular responses as well as enables the entrapment of biologically active molecules and their controllable release for therapeutic action. The approaches of fine-tuning surface chemistry and the combination with other nanomaterials have also enabled targeting of specific cell and tissue types for drug delivery with imaging capacity