University of Mainz

About: University of Mainz is a education organization based out in Mainz, Rheinland-Pfalz, Germany. It is known for research contribution in the topics: Population & Immune system. The organization has 37673 authors who have published 71163 publications receiving 2497880 citations. The organization is also known as: Johannes Gutenberg-Universität Mainz & Universität Mainz.

Growing range of correlated motion in a polymer melt on cooling towards the glass transition

Abstract: Many liquids cooled to low temperatures form glasses (amorphous solids) instead of crystals. As the glass transition is approached, molecules become localized and relaxation times increase by many orders of magnitude1. Many features of this ‘slowing down’ are reasonably well described2 by the mode-coupling theory of supercooled liquids3. The ideal form of this theory predicts a dynamical critical temperature T c at which the molecules become permanently trapped in the ‘cage’ formed by their neighbours, and vitrification occurs. Although there is no sharp transition, because molecules do eventually escape their cage, its signature can still be observed in real and simulated liquids. Unlike conventional critical phenomena (such as the behaviour at the liquid–gas critical point), the mode-coupling transition is not accompanied by a diverging static correlation length. But simulation4,5,6,7,8,9,10 and experiment11,12 show that liquids are dynamically heterogeneous, suggesting the possibility of a relevant ‘dynamical’ length scale characterizing the glass transition. Here we use computer simulations to investigate a melt of short, unentangled polymer chains over a range of temperatures for which the mode-coupling theory remains valid. We find that although density fluctuations remain short-ranged, spatial correlations between monomer displacements become long-ranged as T c is approached on cooling. In this way, we identify a growing dynamical correlation length, and a corresponding order parameter, associated with the glass transition. This finding suggests a possible connection between well established concepts in critical phenomena and the dynamics of glass-forming liquids.

Radiatively Induced Neutrino Masses and Large Higgs-Neutrino Couplings in the Standard Model with Majorana Fields

Abstract: The Higgs sector of the Standard Model (SM) with one right-handed neutrino per family is systematically analyzed. In a model with intergenerational independent mixings between families, we can account for very light neutrinos acquiring Majorana masses radiatively at the first electroweak loop level. We also find that in such a scenario the Higgs coupling to the light-heavy neutrinos and to the heavy-heavy ones may be remarkably enhanced with significant implications for the production of these heavy neutrinos at high energy colliders.

Osteonecrosis of the jaws in patients treated with bisphosphonates - histomorphologic analysis in comparison with infected osteoradionecrosis.

Abstract: Background: Patients treated with bisphosphonates because of bone metastases have been shown to develop osteonecrosis of the jaws. In the present study, we examined the histologic findings of these cases. As similarities between this disorder and infected osteoradionecrosis (IORN) are described, both lesions were compared. Methods: We investigated eight patients with bisphosphonate treatment and osteonecrosis (four female, four male; median age: 65.6 years; cancer: multiple myeloma in five patients, breast cancer in three patients; mandibular involvement in five patients, maxillar involvement in three cases), and 10 patients suffering from IORN (all male; median age: 61.3 years; cancer: squamous cell carcinoma in nine patients, adenoid cystic carcinoma in one patient; mandibular involvement in all cases). Multicentric and bilateral involvement was common in the bisphosphonate group. Histologically, the bone revealed diffuse and patchy areas of necrosis in the bisphosphonate group, while in IORN osteonecrosis was larger and not diffusely distributed. Results: In all cases, we found Actinomyces attached to the necrotic bone tissue. In five of eight bisphosphonates cases, and in six of 10 IORN cases, numerous osteoclasts could be detected close to vital bone exhibiting signs of bone resorption. Pseudoepitheliomatous hyperplasia (PH) was revealed in five of eight bisphosphonate patients, and in seven of 10 IORN patients. Conclusion: We conclude that Actinomyces is involved in the chronic, non-healing inflammatory processes as a characteristic feature of both diseases. Together with the associated presence of increased osteoclast numbers, we suggest that both factors may be involved in osteolytic mechanisms.

Fractional master equations and fractal time random walks.

Abstract: Fractional master equations containing fractional time derivatives of order 0\ensuremath{\le}1 are introduced on the basis of a recent classification of time generators in ergodic theory. It is shown that fractional master equations are contained as a special case within the traditional theory of continuous time random walks. The corresponding waiting time density \ensuremath{\psi}(t) is obtained exactly as \ensuremath{\psi}(t)=(${\mathit{t}}^{\mathrm{\ensuremath{\omega}}\mathrm{\ensuremath{-}}1}$/C)${\mathit{E}}_{\mathrm{\ensuremath{\omega}},\mathrm{\ensuremath{\omega}}}$(-${\mathit{t}}^{\mathrm{\ensuremath{\omega}}}$/C), where ${\mathit{E}}_{\mathrm{\ensuremath{\omega}},\mathrm{\ensuremath{\omega}}}$(x) is the generalized Mittag-Leffler function. This waiting time distribution is singular both in the long time as well as in the short time limit.