387 research outputs found
Asymptotics of skew orthogonal polynomials
Exact integral expressions of the skew orthogonal polynomials involved in
Orthogonal (beta=1) and Symplectic (beta=4) random matrix ensembles are
obtained: the (even rank) skew orthogonal polynomials are average
characteristic polynomials of random matrices. From there, asymptotics of the
skew orthogonal polynomials are derived.Comment: 17 pages, Late
Semi-classical Laguerre polynomials and a third order discrete integrable equation
A semi-discrete Lax pair formed from the differential system and recurrence
relation for semi-classical orthogonal polynomials, leads to a discrete
integrable equation for a specific semi-classical orthogonal polynomial weight.
The main example we use is a semi-classical Laguerre weight to derive a third
order difference equation with a corresponding Lax pair.Comment: 11 page
Constructing solutions to the Bj\"orling problem for isothermic surfaces by structure preserving discretization
In this article, we study an analog of the Bj\"orling problem for isothermic
surfaces (that are more general than minimal surfaces): given a real analytic
curve in , and two analytic non-vanishing orthogonal
vector fields and along , find an isothermic surface that is
tangent to and that has and as principal directions of
curvature. We prove that solutions to that problem can be obtained by
constructing a family of discrete isothermic surfaces (in the sense of Bobenko
and Pinkall) from data that is sampled along , and passing to the limit
of vanishing mesh size. The proof relies on a rephrasing of the
Gauss-Codazzi-system as analytic Cauchy problem and an in-depth-analysis of its
discretization which is induced from the geometry of discrete isothermic
surfaces. The discrete-to-continuous limit is carried out for the Christoffel
and the Darboux transformations as well.Comment: 29 pages, some figure
Characterization of cell death caused by diplodiatoxin and dipmatol, toxic metabolites of Stenocarpella maydis
Diplodiosis, a neuromycotoxicosis of cattle and sheep grazing on mouldy cobs infected by
Stenocarpella maydis, is considered the last major veterinary mycotoxicosis for which the
causative mycotoxin is still unknown. The current study was aimed at characterizing the cell
death observed in mouse neuroblastoma (Neuro-2a), Chinese hamster ovary (CHO-K1) and
Madin–Darby bovine kidney (MDBK) cell lines exposed to the S. maydis metabolites (i.e.
diplodiatoxin and dipmatol) by investigating the roles of necrosis and apoptosis. Necrosis
was investigated using the lactate dehydrogenase (LDH) leakage and propidium iodide (PI)
flow cytometry assays and apoptosis was evaluated using the caspase-3/7 and Annexin V
flow cytometry assays. In addition, transmission electron microscopy (TEM) was used to
correlate the cell death pathways observed in this study with their typical morphologies. Both
diplodiatoxin and dipmatol (750 ÎĽM) induced necrosis and caspase-dependent apoptosis in
Neuro-2a, CHO-K1 and MDBK cells. Ultrastructurally, the two mycotoxins induced
mitochondrial damage, cytoplasmic vacuolation and nuclear fragmentation in the three cell
lines. These findings have laid a foundation for future studies aimed at elucidating in detail
the mechanism of action of the S. maydis metabolites.This work was supported by the International Foundation for Science (IFS), Stockholm, Sweden, through a grant to MG Masango (Grantee Number : B/5114-1), the National Research Foundation (NRF) and the Joy Liebenberg Trust Fund (Grantee Number : MasangoJT).http://www.elsevier.com/locate/toxiconhb2016Paraclinical Science
High Pressure Thermoelasticity of Body-centered Cubic Tantalum
We have investigated the thermoelasticity of body-centered cubic (bcc)
tantalum from first principles by using the linearized augmented plane wave
(LAPW) and mixed--basis pseudopotential methods for pressures up to 400 GPa and
temperatures up to 10000 K. Electronic excitation contributions to the free
energy were included from the band structures, and phonon contributions were
included using the particle-in-a-cell (PIC) model. The computed elastic
constants agree well with available ultrasonic and diamond anvil cell data at
low pressures, and shock data at high pressures. The shear modulus and
the anisotropy change behavior with increasing pressure around 150 GPa because
of an electronic topological transition. We find that the main contribution of
temperature to the elastic constants is from the thermal expansivity. The PIC
model in conjunction with fast self-consistent techniques is shown to be a
tractable approach to studying thermoelasticity.Comment: To be appear in Physical Review
Stress-induced anhedonia is associated with hypertrophy of medium spiny neurons of the nucleus accumbens
There is accumulating evidence that the nucleus accumbens (NAc) has an important role in the pathophysiology of depression. As the NAc is a key component in the neural circuitry of reward, it has been hypothesized that anhedonia, a core symptom of depression, might be related to dysfunction of this brain region. Neuronal morphology and expression of plasticity-related molecules were examined in the NAc of rats displaying anhedonic behavior (measured in the sucrose-consumption test) in response to chronic mild stress. To demonstrate the relevance of our measurements to depression, we tested whether the observed changes were sensitive to reversal with antidepressants (imipramine and fluoxetine). Data show that animals displaying anhedonic behavior display an hypertrophy of medium spiny neurons in the NAc and, in parallel, have increased expression of the genes encoding for brain-derived neurotrophic factor, neural cell adhesion molecule and synaptic protein synapsin 1. Importantly, the reversal of stress-induced anhedonia by antidepressants is linked to a restoration of gene-expression patterns and dendritic morphology in the NAc. Using an animal model of depression, we show that stress induces anhedonic behavior that is associated with specific changes in the neuronal morphology and in the gene-expression profile of the NAc that are effectively reversed after treatment with antidepressants.The present work was funded by the Portuguese Foundation for Technology (FCT), project PTDC/SAU-NEU/105180/2008. FM and PL are recipients of postdoctoral fellowships and MM is recipient of a doctoral fellowship, all from FCT, Portugal
Evaluation of the efficacy of d-penicillamine and trientine as copper chelators using an in vitro technique involving ovine red blood cells
An in vitro technique for haemolysing ovine red blood cells with copper sulphate was standardized to induce c 50% haemolysis with 0,5 mM CuSO₄ after incubation for 14 h at 38°C. This technique was then applied to test the efficacy of trientine and d-penicillamine in preventing haemolysis. Trientine concentrations of 0,5; 1,0 and 1,5 mM were found to be the most effective (P<0,05) in reducing copper-induced haemolysis. One and 1,5 mM concentrations of d-penicillamine were also effective (P< 0,05), but in this experiment a 0,5 mM concentration failed to protect the erythrocytes.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Palabora Mining Company.mn201
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