Glycocalyx production in teleosts [Translation from: Verhandlungen der Deutschen Zoologischen Gesellschaft, p.286, 1970]

Shielding the organism against harmful effects from the environment is one of the most important tasks of the outer covering of all animals. The epidermis of primarily aquatic organisms and the epithelia of organs which are exposed to water, such as the digestive or the urinary system, possess a film of glycoproteins and mucopolysaccharides, the glycocalyx. This short paper examines the relationship of the mucus cells with the glycocalyx

Slip avalanches in crystal plasticity: scaling of the avalanche cutoff

Plastic deformation of crystals proceeds through a sequence of intermittent slip avalanches with scale-free (power-law) size distribution. On macroscopic scales, however, plastic flow is known to be smooth and homogeneous. In the present letter we use a recently proposed continuum model of slip avalanches to systematically investigate the nature of the cut-off which truncates scale-free behavior at large avalanche sizes. The dependence of the cut-off on system size, geometry, and driving mode, but also on intrinsic parameters such as the strain hardening rate is established. Implications for the observability of avalanche behavior in microscopic and macroscopic samples are discussed.Comment: 12 pages, 4 figure

Homogeneous Gold Catalysis through Relativistic Effects: Addition of Water to Propyne

In the catalytic addition of water to propyne the Au(III) catalyst is not stable under non-relativistic conditions and dissociates into a Au(I) compound and Cl2. This implies that one link in the chain of events in the catalytic cycle is broken and relativity may well be seen as the reason why Au(III) compounds are effective catalysts.Comment: 12 pages, 3 figures, 1 tabl

Strain bursts in plastically deforming Molybdenum micro- and nanopillars

Plastic deformation of micron and sub-micron scale specimens is characterized by intermittent sequences of large strain bursts (dislocation avalanches) which are separated by regions of near-elastic loading. In the present investigation we perform a statistical characterization of strain bursts observed in stress-controlled compressive deformation of monocrystalline Molybdenum micropillars. We characterize the bursts in terms of the associated elongation increments and peak deformation rates, and demonstrate that these quantities follow power-law distributions that do not depend on specimen orientation or stress rate. We also investigate the statistics of stress increments in between the bursts, which are found to be Weibull distributed and exhibit a characteristic size effect. We discuss our findings in view of observations of deformation bursts in other materials, such as face-centered cubic and hexagonal metals.Comment: 14 pages, 8 figures, submitted to Phil Ma

Virus-like-vaccines against HIV

Protection against chronic infections has necessitated the development of ever-more potent vaccination tools. HIV seems to be the most challenging foe, with a remarkable, poorly immunogenic and fragile surface glycoprotein and the ability to overpower the cell immune system. Virus-like-particle (VLP) vaccines have emerged as potent inducers of antibody and helper T cell responses, while replication-deficient viral vectors have yielded potent cytotoxic T cell responses. Here, we review the emerging concept of merging these two technologies into virus-like-vaccines (VLVs) for the targeting of HIV. Such vaccines are immunologically perceived as viruses, as they infect cells and produce VLPs in situ, but they only resemble viruses, as the replication defective vectors and VLPs cannot propagate an infection. The inherent safety of such a platform, despite robust particle production, is a distinct advantage over live-attenuated vaccines that must balance safety and immunogenicity. Previous studies have delivered VLVs encoded in modified Vaccinia Ankara vectors and we have developed the concept into a single-reading adenovirus-based technology capable of eliciting robust CD8+ and CD4+ T cells responses and trimer binding antibody responses. Such vaccines offer the potential to display the naturally produced immunogen directly and induce an integrated humoral and cellular immune response

The convergence of the ab-initio many-body expansion for the cohesive energy of solid mercury

A many-body expansion for mercury clusters of the form E = \sum_{i<j}\Delta \epsilon_{ij} + \sum_{i<j<k}\Delta \epsilon_{ijk} + ... \quad, does not converge smoothly with increasing cluster size towards the solid state. Even for smaller cluster sizes (up to n=6), where van der Waals forces still dominate, one observes bad convergence behaviour. For solid mercury the convergence of the many-body expansion can dramatically be improved by an incremental procedure within an embedded cluster approach. Here one adds the coupled cluster many-body electron correlation contributions of the embedded cluster to the bulk HF energy. In this way we obtain a cohesive energy (not corrected for zero-point vibration) of 0.79 eV in perfect agreement with the experimental value.Comment: 10 pages, 3 figures, accepted PR

Cohesive energies of cubic III-V semiconductors

Cohesive energies for twelve cubic III-V semiconductors with zincblende structure have been determined using an ab-initio scheme. Correlation contributions, in particular, have been evaluated using the coupled-cluster approach with single and double excitations (CCSD). This was done by means of increments obtained for localized bond orbitals and for pairs and triples of such bonds. Combining these results with corresponding Hartree-Fock data, we recover about 92 \% of the experimental cohesive energies.Comment: 16 pages, 1 figure, late

First identification of large electric monopole strength in well-deformed rare earth nuclei

Excited states in the well-deformed rare earth isotopes $^{154}$Sm and $^{166}$Er were populated via ``safe'' Coulomb excitation at the Munich MLL Tandem accelerator. Conversion electrons were registered in a cooled Si(Li) detector in conjunction with a magnetic transport and filter system, the Mini-Orange spectrometer. For the first excited $0^+$ state in $^{154}$Sm at 1099 keV a large value of the monopole strength for the transition to the ground state of $\rho^2(\text{E0}; 0^+_2 \to 0^+_\text{g}) = 96(42)\cdot 10^{-3}$ could be extracted. This confirms the interpretation of the lowest excited $0^+$ state in $^{154}$Sm as the collective $\beta$-vibrational excitation of the ground state. In $^{166}$Er the measured large electric monopole strength of $\rho^2(\text{E0}; 0^+_4 \to 0^+_1) = 127(60)\cdot 10^{-3}$ clearly identifies the $0_4^+$ state at 1934 keV to be the $\beta$-vibrational excitation of the ground state.Comment: submitted to Physics Letters