Single-walled carbon nanotubes (CNTs) may enable the fabrication of integrated circuits smaller than 10 nanometers, but this would require scalable production of dense and electronically pure semiconducting nanotube arrays on wafers. We developed a multiple dispersion and sorting process that resulted in extremely high semiconducting purity and a dimension-limited self-alignment (DLSA) procedure for preparing well-aligned CNT arrays (within alignment of 9 degrees) with a tunable density of 100 to 200 CNTs per micrometer on a 10-centimeter silicon wafer. Top-gate field-effect transistors (FETs) fabricated on the CNT array show better performance than that of commercial silicon metal oxide–semiconductor FETs with similar gate length, in particular an on-state current of 1.3 milliamperes per micrometer and a recorded transconductance of 0.9 millisiemens per micrometer for a power supply of 1 volt, while maintaining a low room-temperature subthreshold swing of <90 millivolts per decade using an ionic-liquid gate. Batch-fabricated top-gate five-stage ring oscillators exhibited a highest maximum oscillating frequency of >8 gigahertz.
We describe the design, synthesis and application of a sensitive, selective, and fast fluorescent probe for H 2 S detection. A linear relationship between emission intensity and sulfide concentration was observed in biological bovine plasma systems. With this probe, we were able to estimate the sulfide concentration in mouse blood plasma and brain tissues.
Polyamines play an important role in plant response to abiotic stress. S-adenosyl-l-methionine decarboxylase (SAMDC) is one of the key regulatory enzymes in the biosynthesis of polyamines. In order to better understand the effect of regulation of polyamine biosynthesis on the tolerance of high-temperature stress in tomato, SAMDC cDNA isolated from Saccharomyces cerevisiae was introduced into tomato genome by means of Agrobacterium tumefaciens through leaf disc transformation. Transgene and expression was confirmed by Southern and Northern blot analyses, respectively. Transgenic plants expressing yeast SAMDC produced 1.7- to 2.4-fold higher levels of spermidine and spermine than wild-type plants under high temperature stress, and enhanced antioxidant enzyme activity and the protection of membrane lipid peroxidation was also observed. This subsequently improved the efficiency of CO(2) assimilation and protected the plants from high temperature stress, which indicated that the transgenic tomato presented an enhanced tolerance to high temperature stress (38 degrees C) compared with wild-type plants. Our results demonstrated clearly that increasing polyamine biosynthesis in plants may be a means of creating high temperature-tolerant germplasm.
SummaryRhamnolipid acts as a virulence factor during Pseudomonas aeruginosa infection. Here, we show that deletion of the catabolite repression control (crc) gene in P. aeruginosa leads to a rhamnolipid-negative phenotype. This effect is mediated by the downregulation of rhl quorum sensing (QS). We discover that a disruption of the gene encoding the Lon protease entirely offsets the effect of crc deletion on the production of both rhamnolipid and rhl QS signal C4-HSL. Crc is unable to bind lon mRNA in vitro in the absence of the RNA chaperon Hfq, while Crc contributes to Hfq-mediated repression of the lon gene expression at a posttranscriptional level. Deletion of crc, which results in up-regulation of lon, significantly reduces the in vivo stability and abundance of the RhlI protein that synthesizes C4-HSL, causing the attenuation of rhl QS. Lon is also capable of degrading the RhlI protein in vitro. In addition, constitutive expression of rhlI suppresses the defects of the crc deletion mutant in rhamnolipid, C4-HSL and virulence on lettuce leaves. This study therefore uncovers a novel posttranscriptional regulatory cascade, CrcHfq/Lon/RhlI, for the regulation of rhamnolipid production and rhl QS in P. aeruginosa.
Transmembrane protein 88 (TMEM88) is a transmembrane protein that plays a crucial role in regulating human stem cell differentiation and embryonic development. However, its expression and clinicopathologic significance in human neoplasms is unclear. In this study, the expression and subcellular localizations of TMEM88 were assessed in 214 cases of non-small cell lung cancer (NSCLC). Notably, TMEM88 was highly expressed in the cytosol of $60% NSCLC specimens examined. Higher expression of cytosolic TMEM88 in NSCLC correlated significantly with poor differentiation, high TNM stage, lymph node metastasis, and inferior survival. In NSCLC cells displaying membrane-localized TMEM88, we observed an inhibition of canonical Wnt signaling due to interactions of TMEM88 with the Wnt pathway factor Dishevelled (DVLS). In contrast, NSCLC cells with cytosol-localized TMEM88 lacked effects on Wnt signaling. Cytosolic interactions of TMEM88 and DVLS increased the expression of phosphorylated, active forms of p38, GSK3b (Thr390), and Snail, thereby reducing the expression of the tight junction-associated proteins ZO-1 and occludin, effects associated with enhanced invasive and metastatic cell characters. Importantly, attenuating the expression of cytosolic TMEM88 reduced metastatic prowess in xenograft models. Overall, our findings show how mislocalization of TMEM88 to the cytosol in NSCLC cells ablates its Wnt pathway regulatory properties, thereby promoting invasion and metastasis by activating the p38-GSK3b-Snail signaling pathway. Cancer Res; 75(21); 4527-37. Ó2015 AACR.
In many fruiting plant species, flower abscission is induced by low light stress. Here, we elucidated how signaling mediated by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) controls low light-induced flower drop in tomato (Solanum lycopersicum). We analyzed the expression patterns of an IDA-Like gene (SlIDL6) during low light-induced flower abscission, and used tandem mass spectrometry to identify and characterize the mature SlIDL6 peptide. Tomato knockout lines were created to investigate the in vivo function of SlIDL6. In addition, yeast one-hybrid assays were used to investigate the binding of the SlWRKY17 transcription factor to the SlIDL6 promoter, and silencing of SlWRKY17 expression delayed low light-induced flower abscission. SlIDL6 was specifically expressed in the abscission zone (AZ) and at high levels during low light-induced abscission and ethylene treatment. SlIDL6 knockout lines showed delayed low light-induced flower drop, and the application of SlIDL6 peptide accelerated abscission. Overexpression of SlIDL6 rescued the ida mutant phenotype in Arabidopsis (Arabidopsis thaliana), suggesting functional conservation between species. SlIDL6-mediated abscission was via an ethylene-independent pathway. We report a SlWRKY17- SlIDL6 regulatory module that functions in low light promoted abscission by increasing the expression of enzymes involved in cell wall remodeling and disassembly.
A geometrical interpretation of the multilayer perceptron (MLP) is suggested in this paper. Some general guidelines for selecting the architecture of the MLP, i.e., the number of the hidden neurons and the hidden layers, are proposed based upon this interpretation and the controversial issue of whether four-layered MLP is superior to the three-layered MLP is also carefully examined.
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