Frankfurt University

Frankfurt am Main, Germany

Frankfurt University

Frankfurt am Main, Germany
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Hartnack C.,CNRS Laboratory of Subatomic Physics and Associated Technologies | Oeschler H.,TU Darmstadt | Leifels Y.,Helmholtz Center for Heavy Ion Research | Bratkovskaya E.L.,Frankfurt University | Aichelin J.,CNRS Laboratory of Subatomic Physics and Associated Technologies
Physics Reports | Year: 2012

We discuss strangeness production close to the threshold in p+A and A+A collision. Comparing the body of available K+, K 0, K-, and Λ data with the IQMD transport code and for some key observables as well with the HSD transport code, we find good agreement for the large majority of the observables. The investigation of the reaction with the help of these codes reveals the complicated interaction of the strange particles with hadronic matter which makes strangeness production in heavy-ion collisions very different from that in elementary interactions. We show how different strange particle observables can be used to study the different facets of this interaction (production, rescattering and potential interaction) which finally merge into a comprehensive understanding of these interactions. We identify those observables which allow for studying (almost) exclusively one of these processes to show how the future high precision experiments can improve our quantitative understanding. Finally, we discuss how the K+ multiplicity can be used to study the hadronic equation of state. © 2011 Elsevier B.V.

News Article | December 8, 2016

The German Research Foundation (DFG) will be providing financial support to the Collaborative Research Center (CRC) 1080 on "Molecular and cellular mechanisms of neuronal homeostasis" for four more years. In addition to Johannes Gutenberg University Mainz (JGU), Goethe University Frankfurt as the CRC's speaker university, the Max Planck Institute for Brain Research, and the Mainz-based Institute of Molecular Biology (IMB) are participating in this research center. A total of some EUR 12 million is being made available in the new funding period that will commence on January 1, 2017. CRC 1080 was established on January 1, 2013 with Johannes Gutenberg University Mainz acting as the speaker university. With the commencement of the new funding phase, the speaker role will be transferred to Frankfurt University which, as a member of the Rhine-Main Neuroscience Network (rmn²), is participating in the CRC with its own research projects. The future coordinator of the CRC, Professor Amparo Acker-Palmer, heads up the Frankfurt Institute for Cell Biology and Neurosciences and is also a fellow of the Gutenberg Research College (GRC) at JGU. Professor Heiko Luhmann, Director of the Institute of Physiology at the Mainz University Medical Center, will take up the post of deputy coordinator. The purpose of the CRC on "Molecular and cellular mechanisms of neuronal homeostasis" is to study the molecular and cellular interactions that enable the brain to maintain a state of functional equilibrium, otherwise known as network homeostasis. New findings should contribute to understanding disease processes in the brain, thus providing insights in the development of innovative new therapies. This might even include the creation of new pharmaceutical agents that could be used to treat cerebral disorders in humans. Specifically, the researchers working at the CRC are investigating different classes of molecules, such as those involved in the control of cell-to-cell interactions and signaling processes. "The extension of funding of the Collaborative Research Center 1080, which studies aspects that offer great potential benefits to society, owes much to our very productive and collaborative research endeavors," pointed out the Chief Scientific Officer of the Mainz University Medical Center, Professor Ulrich Förstermann.

Jeyachandran Y.L.,University of Heidelberg | Terfort A.,Frankfurt University | Zharnikov M.,University of Heidelberg
Journal of Physical Chemistry C | Year: 2012

Exposure of protein-repelling oligo(ethylene glycol) (OEG) terminated alkanethiolate (AT) monolayers to ultraviolet (UV) light results in the damage of the OEG chains and photooxidation of the thiolate headgroups, which can be used for controlled tuning of protein-repelling properties within the so-called UV direct writing (UVDW) approach or for the preparation of mixed OEG-AT/specific-receptor films by so-called UV-promoted exchange reaction (UVPER). Using several model systems, we studied the effect of the wavelength (254-365 nm) on the course and efficiency of UVDW and UVPER applied to different OEG-AT matrices. The cross sections of the UV-induced damage were found to decrease significantly with increasing wavelength of UV light. In accordance with this behavior, the efficiencies of both UVDW and UVPER were maximal at a wavelength of 254 nm, somewhat lower at 313 nm, and lowest at 365 nm. Both UVDW and UVPER allowed a fine-tuning of protein affinity for nonspecific and specific adsorption, respectively, but UVDW did not occur below a certain, wavelength-dependent threshold dose. Performing UVPER below this dose enables us to suppress possible nonspecific adsorption of proteins even in the case of noncomplete exchange of the UV-damaged molecules of the primary OEG-AT matrix by receptor-bearing moieties. The obtained results are of direct relevance for the preparation of high-quality mixed OEG-AT/specific-receptor films and the fabrication of complex protein patterns by UVDW and UVPER lithography. © 2012 American Chemical Society.

Fadini G.P.,Venetian Institute of Molecular Medicine | Losordo D.,Northwestern University | Losordo D.,Baxter Healthcare | Dimmeler S.,Frankfurt University
Circulation Research | Year: 2012

Diverse subsets of endothelial progenitor cells (EPCs) are used for the treatment of ischemic diseases in clinical trials, and circulating EPCs levels are considered as biomarkers for coronary and peripheral artery disease. However, despite significant steps forward in defining their potential for both therapeutic and diagnostic purposes, further progress has been mired by unresolved questions around the definition and the mechanism of action of EPCs. Diverse culturing methods and detection of various combinations of different surface antigens were used to enrich and identify EPCs. These attempts were particularly challenged by the close relationship and overlapping markers of the endothelial and hematopoietic lineages. This article will critically review the most commonly used protocols to define EPCs by culture assays or by fluorescence-activated cell sorter in the context of their therapeutic or diagnostic use. We also delineate new research avenues to move forward our knowledge on EPC biology. © 2012 American Heart Association, Inc.

Tocchio L.F.,Frankfurt University | Becca F.,International School for Advanced Studies | Gros C.,Frankfurt University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We show that backflow correlations in the variational wave function for the Hubbard model greatly improve the previous results given by the Slater-Jastrow state, usually considered in this context. We provide evidence that, within this approach, it is possible to have a satisfactory connection with the strong-coupling regime. Moreover, we show that, for the Hubbard model on the lattice, backflow correlations are essentially short range, inducing an effective attraction between empty (holons) and doubly occupied sites (doublons). In the presence of frustration, we report the evidence that the metal to Mott-insulator transition is marked by a discontinuity of the double occupancy, together with a similar discontinuity of the kinetic term that does not change the number of holons and doublons, while the other kinetic terms are continuous across the transition. Finally, we show the estimation of the charge gap, obtained by particle-hole excitations à la Feynman over the ground-state wave function. © 2011 American Physical Society.

Hirabayashi Y.,University of Tokyo | Doll P.,Frankfurt University | Kanae S.,Tokyo Institute of Technology
Journal of Hydrology | Year: 2010

Glaciers play an important role for freshwater resources, but in global-scale freshwater assessments, their impact on river flows has not yet been taken into account. As a first step, we developed a global glacier model that can be coupled to global land surface and hydrological models. With a spatial resolution of 0.5° by 0.5°, the glacier model HYOGA computes glacier mass balance by a simple degree-day approach for 50. m sub-grid elevation bands, modeling all glaciers within a grid cell as one glacier. The model is tuned individually for each grid cell against observed glacier mass balance data. HYOGA is able to compute glacier mass balances reasonably well, even those of summer accumulation type glaciers. Still, model uncertainty is high, which is, among other reasons, due to the uncertainty of global data sets of temperature and precipitation which do not represent well the climatic situation at glacier sites. We developed a 59-yr (1948-2006) time series of global glacier mass balance and glacier area by driving HYOGA with daily near-surface atmospheric data. According to our computations, most glaciers have lost mass during the study period. Compared to estimates derived from a rather small number of observed glacier mass balances, HYOGA computes larger glacier mass losses in Asia, Europe, Canadian Arctic islands and Svalbard. In accordance with the estimates, average annual mass losses have increased strongly after 1990 as compared to the 30. yrs before. The sea level equivalent of the melt water from glaciers is 0.76. mm/yr water equivalent after 1990 as compared to only 0.34. mm/yr water equivalent before. We computed an acceleration of glacier mass losses after 1990 for all world regions except South America, where the number of gauge observations of precipitation is very small after 1980. © 2010 Elsevier B.V.

Iekushi K.,Frankfurt University | Seeger F.,Frankfurt University | Assmus B.,Frankfurt University | Zeiher A.M.,Frankfurt University | Dimmeler S.,Frankfurt University
Circulation | Year: 2012

Background: Cell therapy with bone marrow-derived mononuclear cells (BMCs) can improve recovery of cardiac function after ischemia; however, the molecular mechanisms are not yet fully understood. MicroRNAs (miRNAs) are key regulators of gene expression and modulate the pathophysiology of cardiovascular diseases. Methods and Results: We demonstrated that intramyocardial delivery of BMCs in infarcted mice regulates the expression of cardiac miRNAs and significantly downregulates the proapoptotic miR-34a. In vitro studies confirmed that the supernatant of BMC inhibited the expression of H2O2-induced miR-34a and cardiomyocytes apoptosis. These effects were blocked by neutralizing antibodies directed against insulin-like growth factor-1 (IGF-1). Indeed, IGF-1 significantly inhibited H2O2-induced miR-34a expression, and miR-34a overexpression abolished the antiapoptotic effect of IGF-1. Likewise, inhibition of IGF-1 signaling in vivo abolished the BMC-mediated inhibition of miR-34 expression and the protective effect on cardiac function and increased apoptosis and cardiac fibrosis. IGF-1 specifically blocked the expression of the precursor and the mature miR-34a, but did not interfere with the transcription of the primary miR-34a demonstrating that IGF-1 blocks the processing of miR-34a. Conclusions: Together, our data demonstrate that the paracrine regulation of cardiac miRNAs by transplanted BMCs contributes to the protective effects of cell therapy. BMCs release IGF-1, which inhibits the processing of miR-34a, thereby blocking cardiomyocyte apoptosis. © 2012 American Heart Association, Inc.

Zielen S.,Frankfurt University | Kardos P.,Group Practice and the Center for Pneumology | Madonini E.,San Carlo Hospital
Journal of Allergy and Clinical Immunology | Year: 2010

Background: Asthma control is now recognized as the main goal of asthma therapy. Guidelines recommend finding the lowest effective dose of inhaled corticosteroids in children with persistent asthma. Objective: The aim of this study was to investigate the efficacy of an allergen-specific immunotherapy with a high-dose hypoallergenic mite preparation (allergoid) as steroid-sparing agent in children with allergic asthma. Methods: Sixty-five children with asthma (Global Initiative for Asthma treatment levels II and III; 6-17 years old), after reaching asthma control with inhaled steroids during a 5-month baseline period, were randomized for subcutaneous mite allergoid immunotherapy (SCIT) plus fluticasone propionate (FP) or FP therapy alone for 2 years. During 2 subsequent 5-month winter periods, steroid therapy was adjusted according to predefined dose steps, determining and comparing the changes in FP dosages and the lowest FP dose sufficient to maintain asthma control. Immunologic and functional investigations were also carried out. Results: Children treated with house dust mite SCIT plus FP were able to significantly reduce the FP dose by more steps (P < .05), compared with the control group on FP alone. The mean daily dose in the immunotherapy group decreased from 330.3 μg in the baseline period to 151.5 μg after 2 treatment years, whereas in the control group the dose decreased from 290.6 μg to 206.3 μg. Compared with the control group, significant improvement was also observed in morning peak expiratory flow (P = .0315). Significantly increased levels of specific IgG1 (P = .0001) and IgG4 (P < .0001) were also observed. Conclusion: Adding a mite allergoid SCIT to pharmacologic treatment is an effective and safe strategy to reduce corticosteroid doses while maintaining disease control in children with mite-induced allergic asthma. © 2010 American Academy of Allergy, Asthma & Immunology.

Cabrera D.,Frankfurt University | Rapp R.,Texas A&M University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The width of the ω meson in cold nuclear matter is computed in a hadronic many-body approach, focusing on a detailed treatment of the medium modifications of intermediate πρ states. The π and ρ propagators are dressed by their self-energies in nuclear matter taken from previously constrained many-body calculations. The pion self-energy includes Nh and δh excitations with short-range correlations, while the ρ self-energy incorporates the same dressing of its 2π cloud with a full 3-momentum dependence and vertex corrections, as well as direct resonance-hole excitations; both contributions were quantitatively fit to total photo-absorption spectra and πN→ρN scattering. Our calculations account for in-medium decays of type ωN→πN(*), ππN(δ), and 2-body absorptions ωNN→NN(*), πNN. This causes deviations of the in-medium ω width from a linear behavior in density, with important contributions from spacelike ρ propagators. The ω width from the ρπ cloud may reach up to 200 MeV at normal nuclear matter density, with a moderate 3-momentum dependence. This largely resolves the discrepancy of linear T-ρ{variant} approximations with the values deduced from nuclear photoproduction measurements. © 2014 The Authors.

The Akko Tower Wreck has been playing tricks with researchers for over 50 years. The shipwreck was discovered during the first maritime archeological survey conducted in Israel using remote sensing technology, in 1966, and bears the distinction of being the first shipwreck identified off the coast of Israel. But the shipwreck is also unique in another respect: to date, researchers have been unable to agree on its identity, and as time passed the mystery only seemed to become more opaque. The shipwreck was discovered in 1966 by the late Dr. Elisha Linder, the pioneer of maritime archeology in Israel and the founder of the Recanati Institute for Maritime Studies at the University of Haifa, working together with a British team. The researchers hypothesized that the ship was sunk at the entrance to the port of Akko by the British during their attempt to prevent entry by the navy of Napoleon Bonaparte in 1799. A map found in a British archive that allegedly belonged to one of the British soldiers who participated in the battle, indicated that the British had indeed sunk a ship at the appropriate location and convinced the researchers that their hypothesis was correct. As the years passed, however, new details emerged. For example -- Napoleon Bonaparte arrived in Akko via land and there would have been no need to sink the ship. Moreover, further exploration of the shipwreck revealed that the vessel was smaller than had originally been believed -- 25 meters rather than 45 -- and was in all probability a merchant ship. However, throughout this period the researchers had no firm scientific evidence supporting any particular hypothesis. This situation has now changed following a new study undertaken by the research student Maayan Cohen, under the supervision of Dr. Deborah Cvikel of the Department of Maritime Civilizations and the Recanati Institute for Maritime Studies at the University of Haifa, together with Prof. Yaacov Kahanov of the Institute for Maritime Studies at the University of Haifa, Dr. Dana Ashkenazi of Tel Aviv University, Prof. Adin Stern of Ben Gurion University, and Dr. Sabina Klein of Frankfurt University. The study uncovered the first scientific evidence from the shipwreck. More than a hundred brass nails were found in the ship, most of them still embedded in the wooden hull components, while others were scattered inside the vessel. Two different types of nails were found, with lengths of approximately 10 centimeters and 6.5 centimeters, respectively. Both types of nails underwent a series of tests that would not have been out of place in a forensic criminal investigation: Measurement of the density of the brass; fluorescent spectroscopic examinations using x-rays (XRF) examining their chemical composition; optical inspection using a light microscope and a scanning electron microscope to determine the quality of the metal casting and the microstructure and structure of various parts of the nails; examination of the rigidity of the material; lead isotope analysis, and so forth. In the final test, the researchers took two brass nails from the ship and two modern steel nails and hammered them in order to examine who each nail penetrated different pieces of wood. The long series of studies revealed numerous details. The microstructure of the nails and the presence of silicon revealed that they had been manufactured using the sand casting method. The researchers found a high proportion of zinc and other substances in the alloy. The composition and rigidity of the nails illuminated the manufacturing process, while the isotope analysis identified the most probable location in which they were made. Drawing together all their findings, the researchers formed the following conclusion: The nails were manufactured in the first half of the nineteenth century, probably at a European foundry using raw materials from Britain. "In light of the research findings, we now believe that this is a European merchant vessel that sunk off the coasts of Akko at some time during the first half of the nineteenth century," the researchers concluded. The research findings were published in the journal Metallography, Microstructure, and Analysis. The International Metallurgical Society awarded the authors its prestigious Buehler Prize for the best metallurgical study published in 2015.

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