5,308 research outputs found
ALICE potential for heavy-flavour physics
The Large Hadron Collider (LHC), where lead nuclei will collide at the
unprecedented c.m.s. energy of 5.5 TeV per nucleon-nucleon pair, will offer new
and unique opportunities for the study of the properties of strongly
interacting matter at high energy density over extended volumes. We will
briefly explain why heavy-flavour particles are well-suited tools for such a
study and we will describe how the ALICE experiment is preparing to make use of
these tools.Comment: 6 pages, 3 figures, prepared for the Proceedings of "Strange Quark
Matter 2007", Levoca, Slovaki
Motion of magnetotactic bacteria swarms in an external field
Magnetotactic bacteria moving on circular orbits form hydrodynamically bound
states. When close to a surface and with the tilting of the field in a
direction close to the perpendicular to this surface these swarms move
perpendicularly to the tilting angle. We describe quantitatively this motion by
a continuum model with couple stress arising from the torques produced by the
rotary motors of the amphitrichous magnetotactic bacteria. The model not only
correctly describes the change of direction of swarm motion while inverting the
tangential field but also predicts reasonable value of the torque produced by
the rotary motors
Characterization of the glass transition in vitreous silica by temperature scanning small-angle X-ray scattering
The temperature dependence of the x-ray scattering in the region below the
first sharp diffraction peak was measured for silica glasses with low and high
OH content (GE-124 and Corning 7980). Data were obtained upon scanning the
temperature at 10, 40 and 80 K/min between 400 K and 1820 K. The measurements
resolve, for the first time, the hysteresis between heating and cooling through
the glass transition for silica glass, and the data have a better signal to
noise ratio than previous light scattering and differential thermal analysis
data. For the glass with the higher hydroxyl concentration the glass transition
is broader and at a lower temperature. Fits of the data to the
Adam-Gibbs-Fulcher equation provide updated kinetic parameters for this very
strong glass. The temperature derivative of the observed X-ray scattering
matches that of light scattering to within 14%.Comment: EurophysicsLetters, in pres
Surface-Enhanced Raman Scattering Microspectroscopy Enables the Direct Characterization of Biomineral-Associated Organic Material on Single Calcareous Microskeletons
Biominerals are composite materials with inorganic and organic components. The latter provide insights into how organisms control mineralization and, if derived from micro/nannofossils, into past climates. Many calcifying organisms cannot be cultured or are extinct; the only materials available for their study are therefore complex environmental samples in which the organism of interest may only be a minor component. There is currently no method for characterizing the biomineral-associated organic material from single particles within such assemblages, so its compositional diversity is unknown. Focusing on coccoliths, we demonstrate that surface-enhanced Raman scattering microspectroscopy can be used to determine the origin and composition of fossil organic matter at the single-particle level in a heterogeneous micro/nannofossil assemblage. This approach may find applications in the study of micro/nannofossil assemblages and uncultivated species, providing evolutionary insights into the macromolecular repertoire involved in biomineralization
In situ measurements of density fluctuations and compressibility in silica glass as a function of temperature and thermal history
In this paper, small-angle X-ray scattering measurements are used to
determine the different compressibility contributions, as well as the
isothermal compressibility, in thermal equilibrium in silica glasses having
different thermal histories. Using two different methods of analysis, in the
supercooled liquid and in the glassy state, we obtain respectively the
temperature and fictive temperature dependences of the isotheraml
compressibility. The values obtained in the glass and supercooled liquid states
are very close to each other. They agree with previous determinations of the
literature. The compressibility in the glass state slightly decreases with
increasing fictive temperature. The relaxational part of the compressibility is
also calculated and compared to previous determinations. We discussed the small
differences between the different determinations
Thymic epithelial tumours: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up†
Targeting cancer cell metabolism in pancreatic adenocarcinoma.
Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second leading cause of cancer death by 2030. Current therapeutic options are limited, warranting an urgent need to explore innovative treatment strategies. Due to specific microenvironment constraints including an extensive desmoplastic stroma reaction, PDAC faces major metabolic challenges, principally hypoxia and nutrient deprivation. Their connection with oncogenic alterations such as KRAS mutations has brought metabolic reprogramming to the forefront of PDAC therapeutic research. The Warburg effect, glutamine addiction, and autophagy stand as the most important adaptive metabolic mechanisms of cancer cells themselves, however metabolic reprogramming is also an important feature of the tumor microenvironment, having a major impact on epigenetic reprogramming and tumor cell interactions with its complex stroma. We present a comprehensive overview of the main metabolic adaptations contributing to PDAC development and progression. A review of current and future therapies targeting this range of metabolic pathways is provided
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