2,404 research outputs found
Non-Steroidal Anti-Inflammatory Drugs in the Carcinogenesisof the Gastrointestinal Tract
It is estimated that underlying infections and inflammatory responses are linked to 15–20% of all deaths from cancer worldwide. Inflammation is a physiologic process in response to tissue damage resulting from microbial pathogen infection, chemical irritation, and/or wounding. Tissues injured throughout the recruitment of inflammatory cells such as
macrophages and neutrophils, generate a great amount of growth factors, cytokines, and reactive oxygen and nitrogen species that may cause DNA damage that in turn predisposes
to the transformation from chronic inflammation to neoplasia. Cyclooxygenase (COX), playing a key role in cell homeostasis, angiogenesis and tumourigenesis, may represent the link between inflammation and cancer. Currently COX is becoming a pharmacological target for cancer prevention and treatment
Electrophysiological Assessment of CNS Abnormalities in Muscular Dystrophy
Patients affected by muscular dystrophies often show CNS abnormalities. Patients with dystrophinopathies exhibit intellectual disabilities and mental retardation, while subjects with facioscapulohumeral muscular dystrophy (FSHD) often show epilepsy. Dystrophin and associated proteins have important roles in the CNS. Many patients with Duchenne and Becker muscular dystrophies (DMD/BMD) have cognitive impairment, learning disability, and variable degrees of mental retardation in addition to progressive muscular weakness. Unfortunately, the assessment of cortical function with TMS in DMD patients has not been able to delineate a clear picture and has yielded contradictory results. No TMS studies have been performed on BMD patients. Repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability, possibly by inducing a short-term increase in synaptic efficacy, and can be used to investigate motor cortex excitability in BMD patients. Changes in the size and threshold of motor evoked potentials (MEPs) and cortical silent period (CSP) duration evoked by rTMS delivered in 5 Hz trains of stimuli at suprathreshold intensity can be tested. Impaired muscular function might be partially compensated by an enhancement of motor excitability at the cortical level and/or at α-motoneuron level. TMS may thus offer a reliable means to characterize also important neurophysiologic and pathophysiologic aspects of cortical involvement in muscular dystrophy
The BMV project: Search for photon oscillations into massive particles
In this contribution to PSAS08 we report on the research activities developed
in our Toulouse group, in the framework of the BMV project, concerning the
search for photon oscillations into massive particles, such as axion-like
particles in the presence of a strong transverse magnetic field. We recall our
main result obtained in collaboration with LULI at \'Ecole Polytechnique
(Palaiseau, France). We also present the very preliminary results obtained with
the BMV experiment which is set up at LNCMP (Toulouse, France).Comment: Proceedings of PSAS'08, to be published in Can. J. Phy
Pressure dependence of the Shubnikov-de Haas oscillation pectrum of beta''-(BEDT-TTF)4(NH4)[Cr(C2O4)3].DMF
The Shubnikov-de Haas (SdH) oscillation spectra of the
beta''-(BEDT-TTF)4(NH4)[Cr(C2O4)\_3].DMF organic metal have been studied in
pulsed magnetic fields of up to either 36 T at ambient pressure or 50 T under
hydrostatic pressures of up to 1 GPa. The ambient pressure SdH oscillation
spectra can be accounted for by up to six fundamental frequencies which points
to a rather complex Fermi surface (FS). A noticeable pressure-induced
modification of the FS topology is evidenced since the number of frequencies
observed in the spectra progressively decreases as the pressure increases.
Above 0.8 GPa, only three compensated orbits are observed, as it is the case
for several other isostructural salts of the same family at ambient pressure.
Contrary to other organic metals, of which the FS can be regarded as a network
of orbits, no frequency combinations are observed for the studied salt, likely
due to high magnetic breakdown gap values or (and) high disorder level
evidenced by Dingle temperatures as large as about 7 K.Comment: To be published in European Physical Journal
Structural determinants for NF-Y/DNA interaction at the CCAAT box
The recently determined crystal structures of the sequence-specific transcription factor NF-Y have illuminated the structural mechanism underlying transcription at the CCAAT box. NF-Y is a trimeric protein complex composed by the NF-YA, NF-YB, and NF-YC subunits. NF-YB and NF-YC contain a histone-like domain and assemble on a head-to-tail fashion to form a dimer, which provides the structural scaffold for the DNA sugar-phosphate backbone binding (mimicking the nucleosome H2A/H2B\ue2\u80\u93DNA assembly) and for the interaction with NF-YA. The NF-YA subunit hosts two structurally extended \uce\ub1-helices; one is involved in NF-YB/NF-YC binding and the other inserts deeply into the DNA minor groove, providing exquisite sequence-specificity for recognition and binding of the CCAAT box. The analysis of these structural data is expected to serve as a powerful guide for future experiments aimed at understanding the role of post-translational modification at NF-Y regulation sites and to unravel the three-dimensional architecture of higher order complexes formed between NF-Y and other transcription factors that act synergistically for transcription activation. Moreover, these structures represent an excellent starting point to challenge the formation of a stable hybrid nucleosome between NF-Y and core histone proteins, and to rationalize the fine molecular details associated with the wide combinatorial association of plant NF-Y subunits
Thermodynamics of second phase conductive filaments
We present a theory of second phase conductive filaments in phase
transformable systems; applications include threshold switches, phase change
memory, and shunting in thin film structures. We show that the average filament
parameters can be described thermodynamically. In agreement with the published
data, the predicted filament current voltage characteristics exhibit negative
differential resistance vanishing at high currents where the current density
becomes a bulk material property. Our description is extendible to filament
transients and allows for efficient numerical simulation
Light and neutron scattering studies of the OH stretching band in liquid and supercritical water
The hydrogen projected OH stretching density of states has been determined by an inelastic neutron scattering experiment in liquid and supercritical water, The results, compared with new measurements of the isotropic Raman spectra at the same state conditions, support the interpretation of the Raman spectra in terms of superposition of the allowed nu(1) band with the overtone of the nu(2) band. (C) 1998 American Institute of Physics
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