The Importance of REST for Development and Function of Beta Cells.

Beta cells are defined by the genes they express, many of which are specific to this cell type, and ensure a specific set of functions. Beta cells are also defined by a set of genes they should not express (in order to function properly), and these genes have been called forbidden genes. Among these, the transcriptional repressor RE-1 Silencing Transcription factor (REST) is expressed in most cells of the body, excluding most populations of neurons, as well as pancreatic beta and alpha cells. In the cell types where it is expressed, REST represses the expression of hundreds of genes that are crucial for both neuronal and pancreatic endocrine function, through the recruitment of multiple transcriptional and epigenetic co-regulators. REST targets include genes encoding transcription factors, proteins involved in exocytosis, synaptic transmission or ion channeling, and non-coding RNAs. REST is expressed in the progenitors of both neurons and beta cells during development, but it is down-regulated as the cells differentiate. Although REST mutations and deregulation have yet to be connected to diabetes in humans, REST activation during both development and in adult beta cells leads to diabetes in mice

Atomic-scale identification of novel planar defect phases in heteroepitaxial YBa2_2Cu3_3O7−δ_{7-\delta} thin films

We have discovered two novel types of planar defects that appear in heteroepitaxial YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO123) thin films, grown by pulsed-laser deposition (PLD) either with or without a La$_{2/3}$Ca$_{1/3}$MnO$_3$ (LCMO) overlayer, using the combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging and electron energy loss spectroscopy (EELS) mapping for unambiguous identification. These planar lattice defects are based on the intergrowth of either a BaO plane between two CuO chains or multiple Y-O layers between two CuO$_2$ planes, resulting in non-stoichiometric layer sequences that could directly impact the high-$T_c$ superconductivity

Synthesis of high-oxidation Y-Ba-Cu-O phases in superoxygenated thin films

It is known that solid-state reaction in high-pressure oxygen can stabilize high-oxidation phases of Y-Ba-Cu-O superconductors in powder form. We extend this superoxygenation concept of synthesis to thin films which, due to their large surface-to-volume ratio, are more reactive thermodynamically. Epitaxial thin films of $\rm{YBa_2Cu_3O_{7-\delta}}$ grown by pulsed laser deposition are annealed at up to 700 atm O$_2$ and 900$^\circ$C, in conjunction with Cu enrichment by solid-state diffusion. The films show clear formation of $\rm{Y_2Ba_4Cu_7O_{15-\delta}}$ and $\rm{Y_2Ba_4Cu_8O_{16}}$ as well as regions of $\rm{YBa_2Cu_5O_{9-\delta}}$ and YBa$_2$Cu$_6$O$_{10-\delta}$ phases, according to scanning transmission electron microscopy, x-ray diffraction and x-ray absorption spectroscopy. Similarly annealed $\rm{YBa_2Cu_3O_{7-\delta}}$ powders show no phase conversion. Our results demonstrate a novel route of synthesis towards discovering more complex phases of cuprates and other superconducting oxides.Comment: Accepted for publication in Physical Review Material

Os desafios para o controle da mosca sul americana.

bitstream/item/82809/1/MAFRA-NETO-Agapomi-n228p10-2013.pd

Metodologia para coleta e manutenção de colônias de Linepithema micans (Forel)(Hymenoptera: Formicidae) em laboratório.

bitstream/item/69747/1/cot118.pd

Acceleration Of Protons To Above 6 MeV Using H2O >Snow> Nanowire Targets

A scheme is presented for using H2O >snow> nanowire targets for the generation of fast protons. This novel method may relax the requirements for very high laser intensities, thus reducing the size and cost of laser based ion acceleration system.Physic

Bioecologia e controle da mosca-das-frutas sul-americana Anastrepha fraterculus (Diptera: Tephritidae) na cultura da videira.

Dentre os insetos que danificam as bagas da videira, a mosca-das-frutas sul-americana é a que apresenta maior importância no sul do Brasil. A espécie se destaca por ser uma das mais polífagas do gênero (registro em 67 espécies de plantas de 18 famílias botânicas) e possuir ampla distribuição no continente americano. este trabalho apresenta a descrição, bioecologia, sintomas, danos, monitoramneto e controle deste inseto sobre a videira.bitstream/CNPUV-2010/11850/1/cir081.pdfDisponível também no formato online

Growth and kinetic Monte Carlo simulation of InAs quantum wires on vicinal substrates

AbstractSelf-assembled quantum structures have been successfully grown for some time now but control over their uniformity has proven difficult due to the stochastic nature of surface diffusion. We have investigated the effect of vicinal InP(001) substrates on the uniformity of InAs quantum wires grown on InGaAlAs lattice-matched to InP using molecular beam epitaxy. Dense quantum wires were grown on both nominally flat and vicinal substrates off-cut by 0.9° toward the [110] direction for comparison. The off-cut angle was chosen to provide terraces which match the orientation and spacing of wires grown on nominally flat substrates. A modest but statistically significant improvement in the size distribution of the wires was observed on vicinal substrates through the analysis of ultrahigh resolution scanning electron micrographs. The interface between the wires and the off-cut substrate was studied using cross-sectional high resolution scanning transmission electron microscopy. In addition, a kinetic Monte Carlo model of epitaxial growth including full strain calculations was developed to further investigate the nucleation process. Using an anisotropic bond model to account for the surface energy of different crystallographic facets, our simulations produced wires similar to those observed experimentally while demonstrating the importance of anisotropic bonding compared to anisotropic diffusion. Growth on vicinal substrates is also simulated here and indicates that off-cut substrates should indeed improve the size distribution of quantum wires under proper growth conditions