12,571 research outputs found
SC author and illustrator Kate Salley Palmer signing book
No full textPhotograph of SC author and illustrator Kate Salley Palmer signing boo
Book signing by SC author and illustrator Kate Salley Palmer
No full textPhotograph of Book signing by SC author and illustrator Kate Salley Palme
XPteg (Xenopus Proximal Tubules-Expressed Gene) Is Essential for Pronephric Mesoderm Specification and Tubulogenesis
No full textRetinoic acid (RA) signaling is important for the early steps of nephrogenic cell fate specification. Here, we report a novel target gene of RA signaling named XPteg (Xenopus proximal tubules-expressed gene) which is critical for pronephric development. XPteg starts to be expressed at the earliest stage of embryonic kidney specification and was restricted to the pronephric proximal tubules during kidney development. Anti-sense morpholino (MO)-mediated knockdown of XPteg perturbed formation of pronephros as demonstrated by reduced expression of pronephric tubule markers. Conversely, overexpression of XPteg promoted endogenous and ectopic expression of those markers and expanded pronephric tubules. Treatment of retinoic acid induced the expression of XPteg in the pronephric field without protein synthesis. Furthermore, we found that the pronephric defects caused by a dominant negative RA receptor could be rescued by coexpression of XPteg. Taken together, these results suggest that XPteg functions as a direct transcriptional target of RA signaling to regulate pronephric tubulogenesis in Xenopus early development. (C) 2009 Elsevier Ireland Ltd. All rights reserved.X1197sciescopu
Comparison of the toxicokinetics of daidzein and bisphenol A in pregnant and non-pregnant DA/Han rats
No full textPotentially adverse human and environmental effects due to hormone mimicry of environmental estrogens are a matter of current concern. Environmental estrogens belong to the socalled endocrine active compounds (EAC) and may alter signalling processes of the endocrine system leading to a broad range of effects during fetal and postnatal development, puberty, adulthood, and aging. A number of synthetic chemicals as well as several plant-derived compounds, socalled phytoestrogens, are known to have weak estrogenic activity. The present study is part of the risk assessment of the weak environmental estrogens daidzein and bisphenol A. The isoflavone daidzein is an important phytoestrogen with respect to dietary exposure (soy beans and soy products) whereas bisphenol A is an industrial chemical that occurs at much lower concentrations as a contaminant in food. The toxicokinetics of these compounds in female pregnant and non-pregnant DA/Han rats after single intravenous application were compared by the use of the Mann-Whitney- U-statistic. --Bisphenol A,daidzein,xenoestrogens,phytoestrogens,endocrine active compounds,Mann-Whitney-U-test
High-resolution clean-sc
No full textIn this paper a high-resolution extension of CLEAN-SC is proposed: HR-CLEAN-SC. Where CLEAN-SC uses peak sources in “dirty maps” to define so-called source components, HR-CLEAN-SC takes advantage of the fact that source components can likewise be derived from points at some distance from the peak, as long as these “source markers” are on the main lobe of the Point Spread Function (PSF). This is very useful when sources are closely spaced together, such that their PSFs interfere. Then, alternative markers can be sought in which the relative influence by PSFs of other source positions is minimised. For those markers the source components better agree with the actual sources, which allows for better estimation of their locations and strengths. This paper outlines the theory needed to understand this approach and discusses applications to 2D and 3D microphone array simulations with closely spaced sources
Photovoltaic properties of close-space sublimated CdTe solar cells
No full textCdS/CdTe solar cells were fabricated by close-space sublimation with a screen-printed Te-rich CdTe source and their photovoltaic properties were investigated by varying the substrate temperature, cell area, and thicknesses of CdTe and ITO layers. The resistivity of CdTe layers employed in this study was 3 x 10(4) Omega cm. The optimum substrate temperature and thickness for CdTe deposition were 600 degrees C and 5 mu m, respectively. The CdTe bulk resistance degraded the cell performance above 6 mu m. As the cell area increased the V-oc remained almost constant, while the J(ae) and FF were strongly degraded because of the increase of the lateral resistance of the ITO layer. The optimum thickness of the ITO layer in this study was 300-450 nm. In this experiment we obtained an efficiency of 9.4% in the 0.5 cm(2) cells. The series resistance of the cell should be further reduced to increase the fill factor and improve the efficiency. (C) 1998 Elsevier Science Ltd. All rights reserved
COARSENING PHENOMENON OF L1(2) PRECIPITATES IN RAPIDLY SOLIDIFIED AL-3AT-PERCENT(TI,V,ZR) SYSTEM
No full textDesign and characteristics of a superconductor bearing
No full textA high-temperature superconductor (HTS) journal bearing was designed for a flywheel energy storage system. A rotor was supported at top and bottom by two HTS bearings. The rotor weight is 4 kg and the length and diameter of shaft were about 300 rum and 40 mm, respectively. Both the top and bottom bearings have two permanent magnet (PM) rings with an iron pole piece separating them. Static properties of the bearing were calculated by frozen image method and verified by experiments. The vertical stiffness of the bearing was 38.9 N/mm. The rotational drag and vibration were measured up to 8000 rpm. The loss coefficient was linear up to 8000 rpm and the final value was 7.5 x E - 6. The average of vibration was about 10 micrometer (zero-peak) except the resonance speed range. Rotation tests were conducted over the same speed range at several chamber pressures. Chamber pressure of 0.4 mtorr is sufficiently low to minimize windage loss
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