Superconductivity in undoped T' cuprates with Tc over 30 K

Undoped cuprates have long been considered to be antiferromagnetic insulators. In this article, however, we report that superconductivity is achieved in undoped T'-RE2CuO4 (RE = Pr, Nd, Sm, Eu, and Gd). Our discovery was performed by using metal-organic decomposition (MOD), an inexpensive and easy-to-implement thin-film process. The keys to prepare the superconducting films are firing with low partial-pressure of oxygen and reduction at low temperatures. The highest Tc of undoped T'-RE2CuO4 is over 30 K, substantially higher than "electron-doped" analogs. Remarkably, Gd2CuO4, even the derivatives of which have not shown superconductivity so far, gets superconducting with Tconset as high as ~ 20 K. The implication of our discovery is briefly discussed.Comment: 22 pages, 5 figures, submitted to Physical Review Letter

Generic phase diagram of "electron-doped" T' cuprates

We investigated the generic phase diagram of the electron doped superconductor, Nd2-xCexCuO4, using films prepared by metal organic decomposition. After careful oxygen reduction treatment to remove interstitial Oap atoms, we found that the Tc increases monotonically from 24 K to 29 K with decreasing x from 0.15 to 0.00, demonstrating a quite different phase diagram from the previous bulk one. The implication of our results is discussed on the basis of tremendous influence of Oap "impurities" on superconductivity and also magnetism in T' cuprates. Then we conclude that our result represents the generic phase diagram for oxygen-stoichiometric Nd2-xCexCuO4.Comment: 12 pages, 4 figures; International Symposium on Superconductivity (ISS) 200

Pitch Patterns in Vocal Expression of “Happiness” and “Sadness” in the Reading Aloud of Prose on the Basis of Selected Audiobooks

The primary focus of this paper is to examine the way the emotional categories of “happiness” and “sadness” are expressed vocally in the reading aloud of prose. In particular, the two semantic categories were analysed in terms of the pitch level and the pitch variability on a corpus based on 28 works written by Charles Dickens. passages with the intended emotional colouring were selected and the fragments found in the corresponding audiobooks. They were then analysed acoustically in terms of the mean F0 and the standard deviation of F0. The results for individual emotional passages were compared with a particular reader’s mean pitch and standard deviation of pitch. The differences obtained in this way supported the initial assumptions that the pitch level and its standard deviation would raise in “happy” extracts but lower in “sad” ones. Nevertheless, not all of these tendencies could be statistically validated and additional examples taken from a selection of random novels by other nineteenth century writers were added. The statistical analysis of the larger samples confirmed the assumed tendencies but also indicated that the two semantic domains may utilise the acoustic parameters under discussion to varying degrees. While “happiness” tends to be signalled primarily by raising F0, “sadness” is communicated mostly by lowering the variability of F0. Changes in the variability of F0 seem to be of less importance in the former case, and shifts in the F0 level less significant in the latter

Effect of the Experimental Design in Automatic Attention Shift Studies : A Comparison of Constant vs. Randmized Stimulus Onset Asynchrony (SOA)

The present study compared two experimental designs used in response time (RT) studies: constant and randomized stimulus onset asynchrony (SOA). Both designs are commonly used in studies of automatic attention shifts. The results revealed that RTs at SOAs of 105 ms and 300 ms with a randomized SOA design were significantly longer than with a constant SOA design. The RT gain (i.e. RTs to uncued stimuli minus RTs to cued stimuli) measured in the constant SOA method was maximal when the SOA was 105 ms. However, the gain disappeared at SOAs of 600 ms and longer. In contrast, with a randomized SOA design, RT gains did not show systematic changes, and gains were similar between SOAs of 105 ms and 1,005 ms. Significantly more errors occurred in uncued trials in shorter SOA conditions (105 ms and 300 ms) when constant SOAs were used. When a randomized SOA design was used, errors were less frequent and occurred at a similar rate between different SOAs. These results suggest that a constant SOA design is more appropriate for studying RT gains with automatic attention shifts

Mislocalization of the E3 Ligase, beta-Transducin Repeat-containing Protein 1 (beta-TrCP1), in Glioblastoma Uncouples Negative Feedback between the Pleckstrin Homology Domain Leucine-rich Repeat Protein Phosphatase 1 (PHLPP1) and Akt

The PH domain leucine-rich repeat protein phosphatase, PHLPP, plays a central role in controlling the amplitude of growth factor signaling by directly dephosphorylating and thereby inactivating Akt. The cellular levels of PHLPP1 have recently been shown to be enhanced by its substrate, activated Akt, via modulation of a phosphodegron recognized by the E3 ligase β-TrCP1, thus providing a negative feedback loop to tightly control cellular Akt output. Here we show that this feedback loop is lost in aggressive glioblastoma but not less aggressive astrocytoma. Overexpression and pharmacological studies reveal that loss of the feedback loop does not result from a defect in PHLPP1 protein or in the upstream kinases that control its phosphodegron. Rather, the defect arises from altered localization of β-TrCP1; in astrocytoma cell lines and in normal brain tissue the E3 ligase is predominantly cytoplasmic, whereas in glioblastoma cell lines and patient-derived tumor neurospheres, the E3 ligase is confined to the nucleus and thus spatially separated from PHLPP1, which is cytoplasmic. Restoring the localization of β-TrCP1 to the cytosol of glioblastoma cells rescues the ability of Akt to regulate PHLPP1 stability. Additionally, we show that the degradation of another β-TrCP1 substrate, β-catenin, is impaired and accumulates in the cytosol of glioblastoma cell lines. Our findings reveal that the cellular localization of β-TrCP1 is altered in glioblastoma, resulting in dysregulation of PHLPP1 and other substrates such as β-catenin

Specific and nontoxic silencing in mammalian cells with expressed long dsRNAs

A number of groups have developed libraries of siRNAs to identify genes through functional genomics. While these studies have validated the approach of making functional RNAi libraries to understand fundamental cellular mechanisms, they require information and knowledge of existing sequences since the RNAi sequences are generated synthetically. An alternative strategy would be to create an RNAi library from cDNA. Unfortunately, the complexity of such a library of siRNAs would make screening difficult. To reduce the complexity, longer dsRNAs could be used; however, concerns of induction of the interferon response and off-target effects of long dsRNAs have prevented their use. As a first step in creating such libraries, long dsRNA was expressed in mammalian cells. The 250 nt dsRNAs were capable of efficiently silencing a luciferase reporter gene that was stably transfected in MDA-MB-231 cells without inducing the interferon response or off-target effects any more than reported for siRNAs. In addition, a long dsRNA expressed in the same cell line was capable of silencing endogenous c-met expression and inhibited cell migration, whereas the dsRNA against luciferase had no effect on c-met or cell migration. The studies suggest that large dsRNA libraries are feasible and that functional selection of genes will be possible