Giant thermopower and figure of merit in single-molecule devices

We present a study of the thermopower $S$ and the dimensionless figure of merit $ZT$ in molecules sandwiched between gold electrodes. We show that for molecules with side groups, the shape of the transmission coefficient can be dramatically modified by Fano resonances near the Fermi energy, which can be tuned to produce huge increases in $S$ and $ZT$. This shows that molecules exhibiting Fano resonances have a high efficiency of thermoelectric cooling which is not present for conventional un-gated molecules with only delocalized states along their backbone.Comment: 4 pages, 4 figure

Anatomy of a catchment: the relation of physical attributes of the Plynlimon catchments to variations in hydrology and water status

International audienceThe Plynlimon headwater catchments in mid-Wales have been a landmark study of water resources in the UK uplands for over 30 years. The main physical features of the catchments have been digitised as the basis for linking new model developments and process understanding. Examples are given of how the main physical attributes are related to land management, hydrology and water quality. These data are also being used to provide insights into catchment processes that may underpin the development of new research. This work is particularly relevant given the need for the assessment of water status under the Water Framework Directive. The paper presents hypothetical management scenarios for the catchments, to show how ecological status may be improved, for example, by selectively restructuring areas of commercial forest. Keywords: Plynlimon, GIS, catchment study, forestry, hydrology, WF

Can soil moisture be mapped onto the terrain?

International audienceSoil moisture heterogeneity has an effect on the rainfall?runoff characteristics of a landscape. The aggregate effect on the mean water balance over an area can be quantified successfully using models such as the PDM (Moore, 1986) and TOPMODEL (Beven and Kirkby, 1979). These rainfall?runoff models have been embedded in the large-scale land surface schemes used in meteorological models. However, there is also a requirement (e.g. model validation) to identify the spatial structure of the fine-scale soil moisture heterogeneity that makes up these aggregate models. In some types of landscape, this will be dictated by topography, in others by soil characteristics, or by a combination of both. A method to distribute area-average soil moisture according to the likely effect of local topography is presented and tested. The heterogeneity of the soil moisture is described by the Xinanxiang distribution (Zhao et al., 1980), commonly used to describe the natural spatial heterogeneity of the landscape. This distribution is then mapped onto the terrain using a topographic index to locate the wettest and driest areas. Soil moisture data from the Wye catchment in Wales and from the Pang catchment in Berkshire, England, are used to test the method. It is found that soil moisture data from the Wye catchment follow the topographic index reasonably well, whereas data from the quick-draining, chalky Pang catchment do not. The conclusion that topographic index is a useful indicator only in some landscapes applies equally to using this mapping method and those models that use topographic index directly. Keywords: soil moisture, heterogeneity, topographic index, dat

Time reversal in thermoacoustic tomography - an error estimate

The time reversal method in thermoacoustic tomography is used for approximating the initial pressure inside a biological object using measurements of the pressure wave made on a surface surrounding the object. This article presents error estimates for the time reversal method in the cases of variable, non-trapping sound speeds.Comment: 16 pages, 6 figures, expanded "Remarks and Conclusions" section, added one figure, added reference

Selective activation of JNK/SAPK by interleukin-1 in rabbit liver is mediated by MKK7

AbstractActivation of jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) by interleukin-1 (IL-1) has been reported in many cells and in rabbit liver. Here we report selective activation of JNK/SAPK, without activation of p38 or p42 mitogen-activated protein kinases (MAPKs), by IL-1 in rabbit liver. We identified an IL-1 regulated JNK/SAPK activator present in rabbit liver using S Sepharose chromatography. It was purified and immunoprecipitated by two antisera to MAP kinase kinase 7 (MKK7). It was not recognised by an antibody to MKK4. We conclude that MKK7 is the activator of JNK/SAPK activated by IL-1 in liver and that JNK/SAPK is the only MAPK activated by IL-1 in liver

Identification of qPCR reference genes suitable for normalizing gene expression in the mdx mouse model of Duchenne muscular dystrophy

The mdx mouse is the most widely-used animal model of the human disease Duchenne muscular dystrophy, and quantitative PCR analysis of gene expression in the muscles of this animal plays a key role in the study of pathogenesis and disease progression and in evaluation of potential therapeutic interventions. Normalization to appropriate stably-expressed reference genes is essential for accurate quantitative measurement, but determination of such genes is challenging: healthy and dystrophic muscles present very different transcriptional environments, further altering with disease progression and muscle use, raising the possibility that no single gene or combination of genes may be stable under all experimental comparative scenarios. Despite the pedigree of this animal model, this problem remains unaddressed. The aim of this work was therefore to comprehensively assess reference gene suitability in the muscles of healthy and dystrophic mice, identifying reference genes appropriate for specific experimental comparisons, and determining whether an essentially universally-applicable set of genes exists. Using a large sample collection comprising multiple muscles (including the tibialis anterior, diaphragm and heart muscles) taken from healthy and mdx mice at three disease-relevant ages, and a panel of sixteen candidate reference genes (FBXO38, FBXW2, MON2, ZFP91, HTATSF1, GAPDH, ACTB, 18S, CDC40, SDHA, RPL13a, CSNK2A2, AP3D1, PAK1IP1, B2M and HPRT1), we used the geNorm, BestKeeper and Normfinder algorithms to identify genes that were stable under multiple possible comparative scenarios. We reveal that no single gene is stable under all conditions, but a normalization factor derived from multiple genes (RPL13a, CSNK2A2, AP3D1 and the widely-used ACTB) appears suitable for normalizing gene expression in both healthy and dystrophic mouse muscle regardless of muscle type or animal age. We further show that other popular reference genes, including GAPDH, are markedly disease- or muscle-type correlated. This study demonstrates the importance of empirical reference gene identification, and should serve as a valuable resource for investigators wishing to study gene expression in mdx mice