1,200 research outputs found
Near room-temperature colossal magnetodielectricity and multiglass properties in partially-disordered La2NiMnO6
We report magnetic, dielectric and magnetodielectric responses of pure
monoclinic bulk phase of partially-disordered La2NiMnO6, exhibiting a spectrum
of unusual properties and establish that this system intrinsically is a true
multiglass with a large magnetodielectric coupling (8-20%) over a wide range of
temperatures (150 - 300 K). Specifically, our results establish a unique way to
obtain colossal magnetodielectricity, independent of any striction effects, by
engineering the asymmetric hopping contribution to the dielectric constant via
the tuning of the relative spin orientations between neighboring magnetic ions
in a transition metal oxide system. We discuss the role of anti-site (Ni-Mn)
disorder in emergence of these unusual properties.Comment: 5 pages, 4 figures, Slightly revised version of previous article in
condmat: arXiv:1202.4319v
Clinical Study Early Postoperative Results after Removal of Cranially Migrated Lumbar Disc Prolapse: Retrospective Comparison of Three Different Surgical Strategies
Background. To compare the early postoperative results of three surgical approaches to lumbar disc herniations that migrated cranially. Minimally invasive techniques such as the translaminar and endoscopic transforaminal approaches are utilized in patients with lumbar disc herniations to gain access to cranially located disc material and to avoid the potentially destabilizing resection of ligament and bone tissue, which is associated with an extended interlaminar approach. Methods. This retrospective study compares the postoperative pain and functional capacity levels of 69 patients who underwent an interlaminar (Group A, = 27), a translaminar (Group B, = 22), or an endoscopic transforaminal procedure (Group C, = 20). Results. Median VAS scores for leg pain decreased significantly from before to after surgery in all groups. Surgical revisions were required in thirteen cases (five in Group A, one in Group B, and seven in Group C; = 0.031). After six weeks, there were significant differences in back pain and functional outcome scores and in the results for the MacNab criteria but not in leg pain scores. Conclusions. The interlaminar and translaminar techniques were the safest and fastest ways of gaining access to cranially migrated disc material and the most effective approaches over a period of six weeks
A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization
This paper describes the design, realization and operation of a prototype
liquid Argon Time Projection Chamber (LAr TPC) detector dedicated to the
development of a novel online monitoring and calibration system exploiting UV
laser beams. In particular, the system is intended to measure the lifetime of
the primary ionization in LAr, in turn related to the LAr purity level. This
technique could be exploited by present and next generation large mass LAr TPCs
for which monitoring of the performance and calibration plays an important
role. Results from the first measurements are presented together with some
considerations and outlook.Comment: 26 pages, 27 figure
Recombinant human erythropoietin in the treatment of chemotherapy-induced anemia and prevention of transfusion requirement associated with solid tumors: A randomized, controlled study
Background: Anemia is a common side effect of anticancer chemotherapy. Blood transfusion, previously the only available treatment for chemotherapy-induced anemia, may result insome clinical or subclinical adverse effects in the recipients. Recombinant human erythropoietin (rhEPO) provides a new treatment modality for chemotherapy-induced anemia. Patients and methods: To evaluate the effect of rhEPO onthe need for blood transfusions and on hemoglobin (Hb)concentrations, 227 patients with solid tumors and chemotherapy-induced anemia were enrolled in a randomized, controlled, clinical trial. Of 189 patients evaluable for efficacy, 101 received 5000 IU rhEPO daily s.c, while 88 patients received no treatment during the 12-week controlled phase of the study. Results: The results demonstrate a statistically significant reduction in the need for blood transfusions (28% vs. 42%, P = 0.028) and in the mean volume of packed red blood cells transfused (152 ml vs. 190 ml, p = 0.044) in patients treated with rhEPO compared to untreated controls. This effect was even more pronounced in patients receiving platinum-based chemotherapy (26% vs. 45%, % 0.038). During the controlled treatment phase, the median Hb values increased in the rhEPO patients while remaining unchanged in the control group. The response was seen in all tumor types. Conclusions: RhEPO administration at a dose of 5000 IU daily s.c. increases hemoglobin levels and reduces transfusionrequirements in chemotherapy-induced anemia, especially during platinum-based chemotherap
Insulin resistance in mice lacking neuronal nitric oxide synthase is related to an alpha-adrenergic mechanism.
BACKGROUND: nitric oxide (NO) plays an important role in the regulation of cardiovascular and glucose homeostasis. Mice lacking the gene encoding the neuronal isoform of nitric oxide synthase (nNOS) are insulin-resistant, but the underlying mechanism is unknown. nNOS is expressed in skeletal muscle tissue where it may regulate glucose uptake. Alternatively, nNOS driven NO synthesis may facilitate skeletal muscle perfusion and substrate delivery. Finally, nNOS dependent NO in the central nervous system may facilitate glucose disposal by decreasing sympathetic nerve activity. METHODS: in nNOS null and control mice, we studied whole body glucose uptake and skeletal muscle blood flow during hyperinsulinaemic clamp studies in vivo and glucose uptake in skeletal muscle preparations in vitro. We also examined the effects of alpha-adrenergic blockade (phentolamine) on glucose uptake during the clamp studies. RESULTS: as expected, the glucose infusion rate during clamping was roughly 15 percent lower in nNOS null than in control mice (89 (17) vs 101 (12) [-22 to -2]). Insulin stimulation of muscle blood flow in vivo, and intrinsic muscle glucose uptake in vitro, were comparable in the two groups. Phentolamine, which had no effect in the wild-type mice, normalised the insulin sensitivity in the mice lacking the nNOS gene. CONCLUSIONS: insulin resistance in nNOS null mice was not related to defective insulin stimulation of skeletal muscle perfusion and substrate delivery or insulin signaling in the skeletal muscle cell, but to a sympathetic alpha-adrenergic mechanism
Kleene Algebras and Semimodules for Energy Problems
With the purpose of unifying a number of approaches to energy problems found
in the literature, we introduce generalized energy automata. These are finite
automata whose edges are labeled with energy functions that define how energy
levels evolve during transitions. Uncovering a close connection between energy
problems and reachability and B\"uchi acceptance for semiring-weighted
automata, we show that these generalized energy problems are decidable. We also
provide complexity results for important special cases
A halo blue straggler on a highly eccentric retrograde orbit
Blue straggler, which are stars that appear to be younger than they should
be, are an important population of unusual stars in both stellar clusters and
the halo field of the Galaxy. Most formation scenarios evoke either stellar
collisions or binary stars that transfer mass or merge. We investigate
high-velocity stars in the Galactic halo and perform a spectral and kinematical
analysis to shed light on their nature and origin. Here we report that
SDSSJ130005.62+042201.6 (J1300+0422 for short) is an A-type star of unusually
large radial velocity (504.6 5 \kms). From a quantitative NLTE (and LTE)
spectral analysis of medium-resolution optical spectra, the elemental
composition is derived. Proper motion measurements combined with a
spectroscopic distance estimate allow us to determine its present space
velocity. Its kinematical properties are derived by integrating the equation of
motion in the Galactic potential. We find J1300+0422 to be metal poor
([M/H]=) and exhibit an -element enrichment (~dex) that
is characteristic of the halo population, as confirmed by a kinematical
analysis of its 3D space motions, which places it on a highly eccentric
retrograde Galactic orbit. The mass of J1300+0422 (1.15 0.10 M)
is higher than the globular cluster turn-off masses indicating that it is a
halo blue straggler star. At a Galactic rest-frame velocity of
467~\kms, the star travels faster than any known blue straggler but is
still bound to the Galaxy.Comment: 6 pages, 7 figures, accepted for publication in A&
Atomic Configuration of Nitrogen Doped Single-Walled Carbon Nanotubes
Having access to the chemical environment at the atomic level of a dopant in
a nanostructure is crucial for the understanding of its properties. We have
performed atomically-resolved electron energy-loss spectroscopy to detect
individual nitrogen dopants in single-walled carbon nanotubes and compared with
first principles calculations. We demonstrate that nitrogen doping occurs as
single atoms in different bonding configurations: graphitic-like and
pyrrolic-like substitutional nitrogen neighbouring local lattice distortion
such as Stone-Thrower-Wales defects. The stability under the electron beam of
these nanotubes has been studied in two extreme cases of nitrogen incorporation
content and configuration. These findings provide key information for the
applications of these nanostructures.Comment: 25 pages, 13 figure
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