9,071 research outputs found
Evaluating the patient-perceived impact of a neratinib special access program in an Australian community pharmacy
Neutron spin resonance as a probe of superconducting gap anisotropy in partially detwinned electron underdoped NaFeCoAs
We use inelastic neutron scattering (INS) to study the spin excitations in
partially detwinned NaFeCoAs which has coexisting static
antiferromagnetic (AF) order and superconductivity ( K, K). In
previous INS work on a twinned sample, spin excitations form a dispersive sharp
resonance near meV and a broad dispersionless mode at
meV at the AF ordering wave vector and its
twinned domain . For partially detwinned
NaFeCoAs with the static AF order mostly occurring at , we still find a double resonance at both wave vectors with
similar intensity. Since characterizes the explicit breaking
of the spin rotational symmetry associated with the AF order, these results
indicate that the double resonance cannot be due to the static and fluctuating
AF orders, but originate from the superconducting gap anisotropy.Comment: 5 pages, 5 figures; PRB, 2015 (the correct final version is now used
Graduate Writing Groups: Evidence-Based Practices for Advanced Graduate Writing Support
Writing centers seek to expand their services beyond tutoring and develop evidence-based practices. Continuing and expanding the existing practices, the authors have adopted graduate writing groups (GWGs) to support graduate writers, especially those working on independent writing projects like a dissertation or article for publication. This article provides an effective model on how to develop and assess virtual graduate writing groups (VGWGs). This replicable, aggregable, and data-supported (RAD) research applied a mixed-methods design with pre- and postsurveys over the three semesters of running the VGWG. It found that the VGWG offered a full range of writing support that met graduate writers’ needs for time-based, skill-based, draft-based, and emotion-based support. Specifically, the VGWG significantly improved students’ approaches to writing in five key areas—goal setting, focusing on dissertation writing, generating plans for writing sessions, writing productivity, and writing progress. Therefore, this study contributes robust empirical validation of this model, suggesting that VGWG is an effective method to sup-port graduate writers and expand writing center services. Also, the authors provide a useful model on how writing centers can effectively assess through pre- and postsurveys in a straightforward manner, an assessment model that has both internal and external benefits
Antiferromagnetic Order of the Ru and Gd in Superconducting RuSr2GdCu2O8
Neutron diffraction has been used to study the magnetic order in
RuSr{2}GdCu2O8. The Ru moments order antiferromagnetically at T{N}=136(2)K,
coincident with the previously reported onset of ferromagnetism. Neighboring
spins are antiparallel in all three directions, with a low T moment of 1.18(6)
mu {B} along the c-axis. Our measurements put an upper limit of ~0.1 mu{B} to
any net zero-field moment, with fields exceeding ~0.4T needed to induce a
measurable magnetization. The Gd ions order independently at T{N}=2.50(2)K with
the same spin configuration. PACS numbers: 74.72.Jt, 75.25.+z, 74.25.Ha,
75.30.KzComment: Four pages, Latex, 5 eps figure
Study of intercalation and deintercalation of Na_xCoO_2 yH_2O single crystals
Single crystals of NaxCoO2 with beta-phase (x=0.55, 0.60 and 0.65),
alpha'-phase (x=0.75) and alpha-phase (x=0.9, 1.0) have been grown by the
floating zone technique. The Na-extraction and hydration were carried out for
the alpha'-sample to get superconducting phase of NaxCoO2.yH2O (x~0.3, y~1.3).
Hydrated single crystals exhibit cracked layers perpendicular to the c-axis due
to a large expansion when the water is inserted into the structure. A study of
intercalation/deintercalation was performed to determine the stability of the
hydrated phase and effects of hydration on the structure of the compound. X-ray
diffraction and Thermogravimetric experiments are used to monitor the process
of water molecules accommodated in and removed from the crystal lattice. The
initial intercalation process takes place with two-water molecules
corresponding to y=0.6) inserted in a formula unit, followed by a group of four
(y=1.3) to form a cluster of Na(H2O)4. Thermogravimetric analysis suggests that
the deintercalation occurs with the removal of the water molecules one by one
from the hydrated cluster at elevated temperatures of approximately 50, 100,
200 and 300 C, respectively. Our investigations reveal that the hydration
process is dynamic and that water molecule inter- and deintercalation follow
different reaction paths in an irreversible way.Comment: 15 pages, 6 figures, figures with higher resolution by email request
from the corresponding autho
The anti-cancer effect of retinoic acid signaling in CRC occurs via decreased growth of ALDH+ colon cancer stem cells and increased differentiation of stem cells
Background: Tumorigenesis is driven by stem cell (SC) overpopulation. BecauseALDH is both a marker for SCs in many tissues and a key enzyme in retinoid acid (RA)signaling, we studied RA signaling in normal and malignant colonic SCs.Hypothesis: RA signaling regulates growth and differentiation of ALDH+ colonicSCs dysregulation of RA signaling contributes to SC overpopulation and colorectalcancer (CRC) development.Methods: We analyzed normal and malignant colonic tissues and CRC cell linesto see if retinoid receptors (RXR &RAR) are exclusively expressed in ALDH+ SCs,and if RA signaling changes during CRC development. We determined whether RAsignaling regulates cancer SC (CSC) proliferation, differentiation, sphere formation,and population size.Results: RXR &RAR were expressed in ALDH+ colonic SCs, but not in MCM2+proliferative cells. Western blotting/immunostaining of CRCs revealed that RAsignaling components become overexpressed in parallel with ALDH overexpression,which coincides with the known overpopulation of ALDH+ SCs that occurs during,and drives, CRC development. Treatment of SCs with all-trans retinoic acid (ATRA)decreased proliferation, sphere formation and ALDH+ SC population size, and induceddifferentiation along the neuroendocrine cell (NEC) lineage.Conclusions: Retinoid signaling, by regulating ALDH+ colonic CSCs, decreases SCproliferation, sphere formation, and population size, and increases SC differentiation toNECs. Dysregulation of RA signaling in colonic SCs likely contributes to overpopulationof ALDH+ SCs and CRC growth.Implications: That retinoid receptors RXR and RAR are selectively expressed inALDH+ SCs indicates RA signaling mainly occurs via ALDH+ SCs, which provides amechanism to selectively target CSCs. © 2018 Impact Journals LLC. All rights reserved
Electron-doping evolution of the low-energy spin excitations in the iron arsenide BaFeNiAs superconductors
We use elastic and inelastic neutron scattering to systematically investigate
the evolution of the low-energy spin excitations of the iron arsenide
superconductor BaFe2-xNixAs2 as a function of nickel doping x. In the undoped
state, BaFe2As2 exhibits a tetragonal-to-orthorhombic structural phase
transition and simultaneously develops a collinear antiferromagnetic (AF) order
below TN = 143 K. Upon electron-doping of x = 0.075 to induce bulk
superconductivity with Tc = 12.3 K, the AF ordering temperature reduces to TN =
58 K.We show that the appearance of bulk superconductivity in
BaFe1.925Ni0.075As2 coincides with a dispersive neutron spin resonance in the
spin excitation spectra, and a reduction in the static ordered moment. For
optimally doped BaFe1.9Ni0.1As2 (Tc = 20 K) and overdoped BaFe1.85Ni0.15As2 (Tc
= 15 K) superconductors, the static AF long-range order is completely
suppressed and the spin excitation spectra are dominated by a resonance and
spin-gap at lower energies. We determine the electron-doping dependence of the
neutron spin resonance and spin gap energies, and demonstrate that the
three-dimensional nature of the resonance survives into the overdoped regime.
If spin excitations are important for superconductivity, these results would
suggest that the three-dimensional character of the electronic superconducting
gaps are prevalent throughout the phase diagram, and may be critical for
superconductivity in these materials
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