Fibroma cemento-osificante gingival mandibular: presentación de un caso

Presentamos el caso clínico de una mujer con un fibroma cemento- osificante gigante dependiente de la encía mandibular de 20 años de evolución. El fibroma cemento-osificante es un tumor poco frecuente, clasificado dentro de las lesiones fibroóseas. Aparece generalmente en hueso y en raras ocasiones afecta a tejidos gingivales, como ocurre en nuestro caso. Es una neoplasia de crecimiento lento y bien delimitada, lo que le confiere un carácter benigno. Con los hallazgos histológicos es difícil diferenciar el fibroma cemento-osificante de otras lesiones tales como el osteoblastoma, el osteosarcoma de bajo grado y particularmente de la displasia fibrosa. Para obtener un diagnóstico preciso es fundamental guiarnos además por la información clínica y radiológica y así llevar a cabo un tratamiento oportuno, que condicione un pronóstico excelente.We report a case of a woman presenting a giant cementoossifying fibroma depending of the mandibular gingivae. The evolution of the process was 20 years. Cemento-ossifying fibroma is a relatively rare tumour classified between fibroosseous lesions. This lesion appears within the bone although in some occasions it involves the gingivae soft tissues, as the case we present. It is a slow-growing and well-defined tumorous lesion, because of this, it is considered as a benign lesion. The histologic findings alone may be similar to other pathologies such as osteoblastoma, low-grade osteosarcoma and particularly to fibrous dysplasia. An accurate diagnosis requires careful clinical, radiological and histological correlation in order to make an optimal treatment and an excellent outcome

Complex magnetic states of heavy fermion compound CeGe

The intermetallic compound CeGe exhibits unusual magnetic behavior due to the interplay between the Kondo and the antiferromagnetic coupling. This particular system is interesting because the Kondo temperature is close to the Néel temperature, resulting in a close competition between the low-temperature interactions, which can be tuned by means of varying external parameters such as pressure and applied magnetic field. Interestingly, magnetization measurements up to 12 kbar reveal that the Néel temperature is not affected by pressure. Measurements of the electrical resistivity, however, show that the sharp upturn appearing below TN is sensitive to pressures up to 15 kbar. This suggests that pressure may change the complex antiferromagnetic spin structure. The validity of an explanation based on the magnetic superzones seen in the rare earths is discussed here

Cryogenic study of the magnetic and thermal stability of retained austenite in nanostructured bainite

First magnetic characterization of a recently developed generation of carbide free bainitic steels, known as Nanobain, has been performed. Stability of its retained austenite at cryogenic temperatures has been studied by means of X-ray diffraction, microscopy, dilatometry and magnetic measurements. Two morphologies for this phase (blocky-type and film-type) appear in a different proportion depending on the chemical composition and the applied thermal treatment. Inhibition of the martensitic transformation, when decreasing the temperature down to −271°C, has been observed in those microstructures with higher proportion of film-type austenite. The paramagnetic state of austenite at room temperature seems to lead to different magnetic behaviors (ferromagnetic, antiferromagnetic) at cryogenic temperatures (T or T being around −23°C in all the studied samples), depending on the proportion of such morphological features. Furthermore, irreversibility with temperature on the evolution of such magnetic behaviors has been observed for all the studied bainitic structures and is proposed to be due to a magnetic proximity effect.This work was supported by the Universidad de Oviedo [PAPI-18-EMERG-26].Peer Reviewe

Coexistence of ferromagnetism and spin glass state in YbNi2 nanoparticles

We report changes on the magnetic behavior of the Heavy-Fermion ferromagnetic YbNi2 alloy when reducing the size of the particles to the nanometer scale by high-energy ball milling. The milling process induces a reduction on the particle size of the bulk alloy down to 10 (2) nm and a lattice strain of 1.8 (2)%, for 30 h of milling time, as calculated from the X-ray diffraction data. The ferromagnetic transition at TC = 10.5 K in the bulk alloy tends to disappear whereas other magnetic transitions arise at lower temperatures with the milling process. The AC magnetic susceptibility of the 30 h milled sample shows a frequency independent peak at 3 K, in a wide range of frequencies, consistent neither with superparamagnetic nor simple freezing of the magnetic moments, and as expected for a ferromagnetic behavior. However, from the specific heat measurements in the 30 h milled sample, a peak at 3.6 K is shifted respect to that observed in the AC magnetic susceptibility, as found in spin glasses. The results are explained by the influence of magnetic inhomogeneities and disorder of the alloys enhanced by the milling process in the ensemble of nanoparticles

Unternehmenskultur und marktorientierte Unternehmensfuehrung: Bestandsaufnahme u. Wirkungsanalyse

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel C 145990 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Myopic decision rules and intertemporal equilibria

SIGLEAvailable from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel C 148137 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Surfactant-assisted production of TbCu2 nanoparticles

The production of surfactant-assisted metallic nanoparticles of TbCu2 has been achieved by the combination of high-energy ball milling in tungsten carbide containers and the use of oleic acid (C18H34O2) and heptane (C7H16). The alloys were first produced in bulk pellets by arc melting and subsequently milled for only 2 and 5 h in oleic acid (15 and 30% mass weight). The powders consist of an ensemble of nanoparticles with a TbCu2 lattice cell volume of ≈215 Å3, an average particle diameter between 9 and 12 nm and inhomogeneous lattice strain of 0.2–0.4%, as deduced from X-ray diffraction data. The nanometric sizes of the crystals with defined lattice planes are close to those obtained by transmission electron microscopy. Raman spectroscopy shows the existence of inelastic peaks between 1000 and 1650 cm−1, a characteristic of C18H34O2. The magnetisation shows a peak at the antiferromagnetic-paramagnetic transition with Néel temperatures around 48 K (below that of bulk alloy) and a distinctive metamagnetic transition at 5 K up to 40 K. The Curie-Weiss behaviour above the transition reveals effective Bohr magneton numbers (≈9.1–9.9 μB) which are close to what is expected for the free Tb3+ ion using Hund’s rules. The metamagnetic transition is slightly augmented with respect to the bulk value, reaching H = 24.5 kOe by the combined effect of the size reduction and the lattice strain increase and the increase of magnetic disorder. At low temperatures, there is irreversibility as a result of the existing magnetic disorder. The moment relaxation follows an Arrhenius model with uncompensated Tb moments, with activation energies between 295 and 326 K and pre-exponential factors between 10−11 and 10−13 s. The results are interpreted as a consequence of the existence of a diamagnetic surfactant which drastically decreases the magnetic coupling between interparticle moments