University of Marburg

About: University of Marburg is a education organization based out in Marburg, Germany. It is known for research contribution in the topics: Population & Gene. The organization has 23195 authors who have published 42907 publications receiving 1506069 citations. The organization is also known as: Philipps University of Marburg & Philipps-Universität.

Polyelectrolyte microcapsules for biomedical applications

Abstract: In this paper we review the recent contributions of polyelectrolyte microcapsules in the biomedical field, comprising in vitro and in vivodrug delivery as well as their applications as biosensors.

Orbital overlap and chemical bonding.

Abstract: The chemical bonds in the diatomic molecules Li(2)-F(2) and Na(2)-Cl(2) at different bond lengths have been analyzed by the energy decomposition analysis (EDA) method using DFT calculations at the BP86/TZ2P level. The interatomic interactions are discussed in terms of quasiclassical electrostatic interactions DeltaE(elstat), Pauli repulsion DeltaE(Pauli) and attractive orbital interactions DeltaE(orb). The energy terms are compared with the orbital overlaps at different interatomic distances. The quasiclassical electrostatic interactions between two electrons occupying 1s, 2s, 2p(sigma), and 2p(pi) orbitals have been calculated and the results are analyzed and discussed. It is shown that the equilibrium distances of the covalent bonds are not determined by the maximum overlap of the sigma valence orbitals, which nearly always has its largest value at clearly shorter distances than the equilibrium bond length. The crucial interaction that prevents shorter bonds is not the loss of attractive interactions, but a sharp increase in the Pauli repulsion between electrons in valence orbitals. The attractive interactions of DeltaE(orb) and the repulsive interactions of DeltaE(Pauli) are both determined by the orbital overlap. The net effect of the two terms depends on the occupation of the valence orbitals, but the onset of attractive orbital interactions occurs at longer distances than Pauli repulsion, because overlap of occupied orbitals with vacant orbitals starts earlier than overlap between occupied orbitals. The contribution of DeltaE(elstat) in most nonpolar covalent bonds is strongly attractive. This comes from the deviation of quasiclassical electron-electron repulsion and nuclear-electron attraction from Coulomb's law for point charges. The actual strength of DeltaE(elstat) depends on the size and shape of the occupied valence orbitals. The attractive electrostatic contributions in the diatomic molecules Li(2)-F(2) come from the s and p(sigma) electrons, while the p(pi) electrons do not compensate for nuclear-nuclear repulsion. It is the interplay of the three terms DeltaE(orb), DeltaE(Pauli), and DeltaE(elstat) that determines the bond energies and equilibrium distances of covalently bonded molecules. Molecules like N(2) and O(2), which are usually considered as covalently bonded, would not be bonded without the quasiclassical attraction DeltaE(elstat).

Anaerobic Microbial Degradation of Hydrocarbons : from Enzymatic Reactions to the Environment

Abstract: Hydrocarbons are abundant in anoxic environments and pose biochemical challenges to their anaerobic degradation by microorganisms. Within the framework of the Priority Program 1319, investigations fun

Strongly Correlated Fermions after a Quantum Quench

Abstract: Using the adaptive time-dependent density-matrix renormalization group method, we study the time evolution of strongly correlated spinless fermions on a one-dimensional lattice after a sudden change of the interaction strength. For certain parameter values, two different initial states (e.g., metallic and insulating) lead to observables which become indistinguishable after relaxation. We find that the resulting quasistationary state is nonthermal. This result holds for both integrable and nonintegrable variants of the system.

Marburg and Ebola Viruses

Abstract: Publisher Summary Filoviruses are among the most pathogenic of human viruses. They are classified as “Biological Level 4” agents (WHO; Risk Group 4) based on their high mortality rate, person-to-person transmission, potential aerosol infectivity, and absence of vaccines and chemotherapy. Molecular analyses of the genomes clearly demonstrated that filoviruses are the closest relatives to Rhabdoviridae and Paramyxoviridae. All nonsegmented negative-stranded (NNS) RNA viruses share a similar genome organization, with conserved regions at both ends encoding the core and L proteins surrounding a variable part in the middle encoding the envelope proteins. Direct detection of virus antigen, virus particles, and viral RNA can be achieved by several assays. Electron microscopy has been particularly useful in the diagnosis of filovirus infections. Viral structures can be visualized by negative contrast electron microscopy after ultracentrifugation and fixation of initial passage cell culture supernatants. Limited knowledge of the epidemiology and clinical picture of filoviral hemorrhagic fever (HP) and inexperience in diagnosing cases and in case in management magnify the danger of an introduction. Filoviruses—like other RNA viruses—presumably have a potential for rapid evolution because of an inherently high error rate of the virus encoded polymerase and a lack of repair mechanisms. The consequence may be a spectrum of genetic variants that are selected by the host for different transmissibility, virulence, and other biological properties.