149 research outputs found
Phase diagram and optical conductivity of La1.8-xEu0.2SrxCuO4
La1.8-xEu0.2SrxCuO4 (LESCO) is the member of the 214 family which exhibits
the largest intervals among the structural, charge ordering (CO), magnetic, and
superconducting transition temperatures. By using new dc transport measurements
and data in the literature we construct the phase diagram of LESCO between x =
0.8 and 0.20. This phase diagram has been further probed in ac, by measuring
the optical conductivity {\sigma}1({\omega}) of three single crystals with x =
0.11, 0.125, and 0.16 between 10 and 300 K in order to associate the
extra-Drude peaks often observed in the 214 family with a given phase. The
far-infrared peak we detect in underdoped LESCO is the hardest among them,
survives up to room temperature and is associated with charge localization
rather than with ordering. At the CO transition for the commensurate doping x =
0.125 instead the extra-Drude peak hardens and a pseudogap opens in
{\sigma}1({\omega}), approximately as wide as the maximum superconducting gap
of LSCO.Comment: 6 pages, 6 figure
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An Alternative to Dye-Based Approaches to Remove Background Autofluorescence From Primate Brain Tissue
Brain tissue contains autofluorescing elements that potentially impede accurate identification of neurons when visualized with fluorescent microscopy. Age-related accumulation of molecules with autofluorescent properties, such as lipofuscin, can possess spectral profiles that invade the typical emission range of fluorophores commonly utilized in fluorescent microscopy. The traditional method for accounting for this native fluorescence is to apply lipophilic dyes that are able to sequester these unwanted signals. While effective, such dyes can present a range of problems including the obstruction of fluorescent probe emissions. The present study utilizes aged primate midbrain tissue stained for tyrosine hydroxylase and calbindin to investigate an image processing approach for removing autofluorescence utilizing spectral imaging and linear unmixing. This technique is then compared against the traditional, dye-based autofluorescence sequestration method using Sudan Black B (SBB). Spectral imaging and linear unmixing yielded significantly higher cell numbers than SBB treatment. This finding suggests that computational approaches for removing autofluorescence in neural tissue are both viable and preferential to dye-based approaches for estimation of cell body numbers.NIA [R01 AG050548, P51 RR000169, F31 AG055263]; McKnight Brain Research FoundationOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Superconductivity Induced by Bond Breaking in the Triangular Lattice of IrTe2
IrTe2, a layered compound with a triangular iridium lattice, exhibits a
structural phase transition at approximately 250 K. This transition is
characterized by the formation of Ir-Ir bonds along the b-axis. We found that
the breaking of Ir-Ir bonds that occurs in Ir1-xPtxTe2 results in the
appearance of a structural critical point in the T = 0 limit at xc = 0.035.
Although both IrTe2 and PtTe2 are paramagnetic metals, superconductivity at Tc
= 3.1 K is induced by the bond breaking in a narrow range of x > xc in
Ir1-xPtxTe2. This result indicates that structural fluctuations can be involved
in the emergence of superconductivity.Comment: 10 pages, 4 figure
Orbital Degeneracy and Peierls Instability in Triangular Lattice Superconductor IrPtTe
We have studied electronic structure of triangular lattice
IrPtTe superconductor using photoemission spectroscopy and
model calculations. Ir core-level photoemission spectra show that Ir
charge modulation established in the low temperature phase of IrTe
is suppressed by Pt doping. This observation indicates that the suppression of
charge modulation is related to the emergence of superconductivity.
Valence-band photoemission spectra of IrTe suggest that the Ir charge
modulation is accompanied by Ir orbital reconstruction. Based on the
photoemission results and model calculations, we argue that the
orbitally-induced Peierls effect governs the charge and orbital instability in
the IrPtTe.Comment: 5 pages,4 figure
Effects of Art from the Heart on Nurse Satisfaction and Patient Well-Being
Introduction. Art programs have been shown to positively affect unit culture, quality of care, and nursing practices. Art interventions improve well-being, reduce stress, and enhance nurse-patient communication. Art from the Heart (AFTH) is an art program that provides art supplies, visual art, and patient About Me pages to patients, families and employees at University of Vermont Medical Center (UVMMC).Objective. Assess the efficacy of AFTH through nursing staff perceptions, understanding, and attitudes toward the program.Methods. Structured interviews were conducted on Baird 4, an adult inpatient ward, at UVMMC. A 19-question survey using Likert scales and short answer formats was administered to nursing staff. Questions assessed perceptions of effects of art on patient anxiety and pain, communication, and job satisfaction. Surveys were analyzed to extract major and minor themes.Results. Twenty-eight interviews were obtained and two major themes emerged: nurse satisfaction and patient well-being. Nursing staff satisfaction minor themes included improved productivity, promoting conversation, and creating a positive influence on the unit. Respondents reported that AFTH helped initiate conversations with patients (100% of respondents) and reduced workday stress (68%). The second major theme, patient well-being, included benefits to patients with dementia, providing comfort, and serving as an outlet or distraction. Utilizing AFTH improved perceived patient mood (100%), health (78.5%), and reduced patient anxiety (89.3%).Conclusions. AFTH provides positive benefits by reducing nursing staff stress and perceived patient anxiety; improving communication, perceived patient mood and health; and creating a sense of community. AFTH should be expanded to the entire 6 Community Agency: Burlington City Arts, Art from the Hearthttps://scholarworks.uvm.edu/comphp_gallery/1240/thumbnail.jp
Electronic structure reconstruction by orbital symmetry breaking in IrTe2
We report an angle-resolved photoemission spectroscopy (ARPES) study on IrTe2
which exhibits an interesting lattice distortion below 270 K and becomes
triangular lattice superconductors by suppressing the distortion via chemical
substitution or intercalation. ARPES results at 300 K show multi-band Fermi
surfaces with six-fold symmetry which are basically consistent with band
structure calculations. At 20 K in the distorted phase, whereas the flower
shape of the outermost Fermi surface does not change from that at 300 K,
topology of the inner Fermi surfaces is strongly modified by the lattice
distortion. The Fermi surface reconstruction by the distortion depends on the
orbital character of the Fermi surfaces, suggesting importance of Ir 5d and/or
Te 5p orbital symmetry breaking.Comment: 4pages, 4figure
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