Peptide Paratope Mimics of the Broadly Neutralizing HIV‐1 Antibody b12

The broadly neutralizing HIV‐1 antibody b12 recognizes the CD4 binding site of the HIV‐1 envelope glycoprotein gp120 and efficiently neutralizes HIV‐1 infections in vitro and in vivo. Based on the 3D structure of a b12 ? gp120 complex, we have designed an assembled peptide (b12‐M) that presents the parts of the three heavy‐chain complementarity‐determining regions (CDRs) of b12, which contain the contact sites of the antibody for gp120. This b12‐mimetic peptide, as well as a truncated peptide presenting only two of the three heavy‐chain CDRs of b12, were shown to recognize gp120 in a similar manner to b12, as well as to inhibit HIV‐1 infection, demonstrating functional mimicry of b12 by the paratope mimetic peptides.     

Comparative study of the temporal evolution of atmospheric lead deposition in Scotland and eastern Canada using blanket peat bogs

The temporal evolution of atmospheric lead deposition and its possible sources were assessed in eastern Canada and in western Scotland, using blanket peat bogs as geochemical archives. Short cores were taken from two remote sites located close to the sea. Significant lead enrichments in the upper layers at both sites reflect the increasing emission of lead into the atmosphere due to anthropogenic activities during the last century. At the Scottish site, a region under aeolian influence from Europe, anthropogenic derived lead could be recognized by the distinctive unradiogenic composition (206Pb/207Pb ratios down to approximately 1.115), being clearly different from the pre-industrial values (206Pb/207Pb approximately 1.166). In contrast, the lead pollution in eastern Canada (influenced by North American sources) is identified by a more radiogenic lead isotope composition (206Pb/207Pb ratios up to approximately 1.199) compared to preindustrial values (206Pb/207Pb approximately 1.161). Emission inventories and isotope characteristics suggest that industrial (coal burning, mining) and traffic (leaded gasoline) outputs are the most likely sources during the first and the second half of the 20th century, respectively, in both, western Scotland and eastern Canada alike. The Scottish record is in line with previous studies of past atmospheric lead deposition. However, the Canadian deposit suggests that the wind derived, pre-industrial lead, is less radiogenic as previously implied using sediment archives. These results are thus the first to report pre-industrial lead isotope ratios and concentrations of atmospheric derived aerosols in North America.     

Changes in the location and function of small water bodies in the upper Sanna River catchment—case study (SE Poland)

The article summarises the results of analyses of temporal and spatial changes in the location of small water bodies in the upper Sanna River catchment between the fifteenth and twenty-first centuries. The investigations were conducted on historical sources and cartographic data using GIS tools and inventory files. Natural (location of springs, groundwater depth, geomorphology of valleys), anthropogenic factors (quarries, excavations) and historical determinants of construction of the water reservoirs are presented. Additionally, changes in the economic (fish farming, mills), defence and industrial (paper and steel mills, bloomeries, fulleries) functions of the water bodies have been analysed. The changes in the functions of the water bodies were often influenced by the changing ownership. The results have application significance on a local and regional scale.     

Analytical Elastic Solution Based on Fourier Series for a Laterally Confined Granular Column

This paper presents an analytical solution methodology for the complete stress and displacement fields of a laterally confined granular column loaded from the top end. The granular column is idealized as a homogeneous isotropic elastic medium with Coulomb’s friction at the lateral boundary. The solution methodology consists of an analytical procedure that incorporates a potential approach with trigonometric series and Bessel functions, finite Fourier transforms and the superposition method, and an iterative algorithm to satisfy the Coulomb’s friction condition at the lateral boundary. Stress and displacement fields are computed for a specific example and found completely consistent with corresponding finite element results. Key characteristics, computational errors, the convergence behavior, and restrictions of the present approach are discussed. The methodology developed herein can be beneficially applied in the validation process of numerical simulation techniques in granular mechanics such as finite or discrete element methods.     

3D-Printed Broadband Dielectric Tube Terahertz Waveguide with Anti-Reflection Structure

We demonstrate broadband, low loss, and close-to-zero dispersion guidance of terahertz (THz) radiation in a dielectric tube with an anti-reflection structure (AR-tube waveguide) in the frequency range from 0.2 to 1.0 THz. The anti-reflection structure (ARS) consists of close-packed cones in a hexagonal lattice arranged on the outer surface of the tube cladding. The feature size of the ARS is in the order of the wavelength between 0.2 and 1.0 THz. The waveguides are fabricated with the versatile and cost efficient 3D-printing method. Terahertz time-domain spectroscopy (THz-TDS) measurements as well as 3D finite-difference time-domain simulations (FDTD) are performed to extensively characterize the AR-tube waveguides. Spectrograms, attenuation spectra, effective phase refractive indices, and the group-velocity dispersion parameters β ₂ of the AR-tube waveguides are presented. Both the experimental and numerical results confirm the extended bandwidth and smaller group-velocity dispersion of the AR-tube waveguide compared to a low loss plain dielectric tube THz waveguide. The AR-tube waveguide prototypes show an attenuation spectrum close to the theoretical limit given by the infinite cladding tube waveguide.     

Top-down lipidomic screens by multivariate analysis of high-resolution survey mass spectra

Direct profiling of total lipid extracts on a hybrid LTQ Orbitrap mass spectrometer by high-resolution survey spectra clusters species of 11 major lipid classes into 7 groups, which are distinguished by their sum compositions and could be identified by accurately determined masses. Rapid acquisition of survey spectra was employed as a "top-down" screening tool that, together with the computational method of principal component analysis, revealed pronounced perturbations in the abundance of lipid precursors within the entire series of experiments. Altered lipid precursors were subsequently identified either by accurately determined masses or by in-depth MS/MS characterization that was performed on the same instrument. Hence, the sensitivity, throughput and robustness of lipidomics screens were improved without compromising the accuracy and specificity of molecular species identification. The top-down lipidomics strategy lends itself for high-throughput screens complementing ongoing functional genomics efforts.     

Dynamics of killer T cell inflation in viral infections

Upon acute viral infection, a typical cytotoxic T lymphocyte (CTL) response is characterized by a phase of expansion and contraction after which it settles at a relatively stable memory level. Recently, experimental data from mice infected with murine cytomegalovirus (MCMV) showed different and unusual dynamics. After acute infection had resolved, some antigen specific CTL started to expand over time despite the fact that no replicative virus was detectable. This phenomenon has been termed as "CTL memory inflation". In order to examine the dynamics of this system further, we developed a mathematical model analysing the impact of innate and adaptive immune responses. According to this model, a potentially important contributor to CTL inflation is competition between the specific CTL response and an innate natural killer (NK) cell response. Inflation occurs most readily if the NK cell response is more efficient than the CTL at reducing virus load during acute infection, but thereafter maintains a chronic virus load which is sufficient to induce CTL proliferation. The model further suggests that weaker NK cell mediated protection can correlate with more pronounced CTL inflation dynamics over time. We present experimental data from mice infected with MCMV which are consistent with the theoretical predictions. This model provides valuable information and may help to explain the inflation of CMV specific CD8+T cells seen in humans as they age.     

Hydrogen generation by electrolysis and storage in salt caverns: Potentials,economics and systems aspects with regard to the German energy transition

The Plan-DelyKaD project focused on an in-depth comparison of relevant electrolysis technologies, identified criteria for and selected most relevant salt cavern sites in Germany, studied business case potentials for applying hydrogen taken from storage to different end-users and engaged in identifying the future role of hydrogen from large scale storage in the German energy system. The focus of this paper is on the latter three topics above. The bottom-up investigation of most suitable salt cavern sites was used as input for a model-based analysis of microeconomic and macroeconomic aspects. The results identify dimensions and locations of possible hydrogen storages mostly in Northern Germany with ample potential to support the integration of fluctuating renewable electricity into the German power system. The microeconomic analysis demonstrates that the most promising early business case for hydrogen energy from large scale storage is its application as a fuel for the mobility sector. From a system perspective the analysis reveals that an optimized implementation of hydrogen generation via electrolysis and storage in salt caverns will have a positive impact on the power system in terms of reduced curtailments of wind power plants and lower residual peak loads.     

The effect of a Lorentz-force-driven rotating flow on the detachment of gas bubbles from the electrode surface

The enhanced bubble detachment in water electrolysis due to Lorentz-forces is discussed for the case of mainly parallel electric and magnetic fields. Experiments and numerical simulations were carried out to assess the velocity and pressure distribution around single rigid spheres mimicking electrolytic bubbles on a horizontal electrode in the presence of a vertical magnetic field. Astigmatism particle tracking velocimetry delivered the three-dimensional flow field and a finite volume method was used for the computations. Formerly it was assumed that the flow-induced pressure decrease at the bubble's top caused the earlier detachment under magnetic field action. However, the experimental and numerical results obtained here demonstrate that this pressure decrease is too weak as to effectively change the detachment process. Finally, an alternative explanation for the observed bubble behavior is suggested: it might result from the comparatively strong global flow generated by the additive effect of a group of bubbles.