Mesenchymal Stromal Cells from Healthy and Inflamed Human Gingiva Respond Differently to Porphyromonas gingivalis

Gingiva-Derived Mesenchymal Stromal Cells (GMSCs) have been shown to play an important role in periodontitis. However, how P. gingivalis, one of the key etiological agents of the disease, affects healthy (H)- and periodontitis (P)-GMSCs is unknown. To address this problem, we established 10 H-GMSC and 12 P-GMSC lines. No significant differences in morphology, differentiation into chondroblasts and adipocytes, expression of characteristic MSCS markers, including pericyte antigens NG2 and PDGFR, were observed between H- and P-GMSC lines. However, proliferation, cell size and osteogenic potential were higher in P-GMSCs, in contrast to their lower ability to suppress mononuclear cell proliferation. P. gingivalis up-regulated the mRNA expression of IL-6, IL-8, MCP-1, GRO-α, RANTES, TLR-2, HIF-1α, OPG, MMP-3, SDF-1, HGF and IP-10 in P-GMSCs, whereas only IL-6, MCP-1 and GRO-α were up-regulated in H-GMSCs. The expression of MCP-1, RANTES, IP-10 and HGF was significantly higher in P-GMSCs compared to H-GMSCs, but IDO1 was lower. No significant changes in the expression of TLR-3, TLR-4, TGF-β, LAP, IGFBP4 and TIMP-1 were observed in both types of GMSCs. In conclusion, our results suggest that P-GMSCs retain their pro-inflammatory properties in culture, exhibit lower immunosuppressive potential than their healthy counterparts, and impaired regeneration-associated gene induction in culture. All these functions are potentiated significantly by P. gingivalis treatment.     

Quantum-Confinement-Enhanced Thermoelectric Properties in Modulation-Doped GaAs–AlGaAs Core–Shell Nanowires

Nanowires (NWs) hold great potential in advanced thermoelectrics due to their reduced dimensions and low-dimensional electronic character. However, unfavorable links between electrical and thermal conductivity in state-of-the-art unpassivated NWs have, so far, prevented the full exploitation of their distinct advantages. A promising model system for a surface-passivated one-dimensional (1D)-quantum confined NW thermoelectric is developed that enables simultaneously the observation of enhanced thermopower via quantum oscillations in the thermoelectric transport and a strong reduction in thermal conductivity induced by the core–shell heterostructure. High-mobility modulation-doped GaAs/AlGaAs core–shell NWs with thin (sub-40 nm) GaAs NW core channel are employed, where the electrical and thermoelectric transport is characterized on the same exact 1D-channel. 1D-sub-band transport at low temperature is verified by a discrete stepwise increase in the conductance, which coincided with strong oscillations in the corresponding Seebeck voltage that decay with increasing sub-band number. Peak Seebeck coefficients as high as ≈65–85 µV K⁻¹ are observed for the lowest sub-bands, resulting in equivalent thermopower of S²σ ≈ 60 µW m⁻¹ K⁻² and S²G ≈ 0.06 pW K⁻² within a single sub-band. Remarkably, these core–shell NW heterostructures also exhibit thermal conductivities as low as ≈3 W m⁻¹ K⁻¹, about one order of magnitude lower than state-of-the-art unpassivated GaAs NWs.     

Development of automated microrobot-based nanohandling stations for nanocharacterization

Current research work on the development of automated microrobot-based nanohandling stations (AMNSs) using the probe of an atomic force microscope (AFM) as an endeffector is presented. The manipulation of individual multiwalled carbon nanotubes (MWCNTs) and the characterization of biological objects, as for instance cells or ligand-receptor bindings are aspired applications. For this reason, the developed AMNSs have to be integrated both into a scanning electron microscope (SEM) for the nanomanipulation of carbon nanotubes (CNTs) and into an optical microscope for the cell characterization. Such an AMNS combines different micro- and nanomanipulators, each offering three degrees of freedom, in order to perform the coarse and fine positioning between object and endeffector. Piezo-resistive AFM probes are applied as endeffectors allowing to measure the acting forces and to realize force feedback for the station’s control system. First, investigations have been carried out by bending MWCNTs and calculating their Young’s modulus. Electrically conductive adhesives (ECAs) have been developed for the microelectronics industry, and their mechanical properties have to be determined. Therefore an AMNS for the mechanical characterization of thin ECA coatings by nanoindentation inside an SEM is presented as well, showing first experimental results. The three application areas shown in this paper will provide the basis for using the considered materials in MEMS/NEMS- and biosensor-devices.     

Quantum Chemical Studies on the Formation of Ozone Adducts to Aromatic Compounds in Aqueous Solution

The rate constants of the reactions of ozone with nitrobenzene, chlorobenzene, benzene, methylbenzene, methoxybenzene, phenol, 1,3,5-trimethoxybenzene and phenolate ion in aqueous solution span ten orders of magnitude. The logarithms of the rate constants correlate with the Gibbs free energies of adduct formation (ranging from +18.5 to ?21.6 kcal mol^?1) calculated with the help of the Jaguar 7.5 program using a dielectric continuum model to account for solvent effects. The electrophilic nature of these reactions is reflected by good correlations with Mulliken charge and similar parameters of these compounds accessible to quantum chemical calculations. Data on the Gibbs free energies of Criegee ozonide formation are also provided.     

The Reactions of Bromide with Ozone Towards Bromate and the Hypobromite Puzzle: A Density Functional Theory Study

Taking the solvent water into account, the energetics of the reactions of O₃ with Br^? leading to BrO₃ ^? have been calculated by Density Functional Theory at the B3LYP/6–311+G(d)/SCRF =COSMO level. Br^? reversibly forms an adduct, BrOOO^?, (ΔG?=?+6 kJ mol^?1) that decays spin allowed into BrO^? and O₂(¹Δ_g) (ΔG?=?+13 kJ mol^?1). BrO^? undergoes an oxidation to BrO₂ ^? and a reduction to Br^?. This may be accounted for if two different adducts, OBrOOO^? and BrOOOO^?, decay into BrO^? plus O₂ and Br^? plus 2 O₂. After cyclization, OBrOOO^? may also lead to Br^? plus 2 O₂.     

Adaptive cross-approximation for surface reconstruction using radial basis functions

The efficient handling of matrices arising in surface interpolation and approximation with radial basis functions (RBF) is considered. To find a data-sparse approximation of the system matrix, the adaptive cross-approximation (ACA) technique is used. The approximation of the matrix requires O (Nlog² N ) units of storage and arithmetic operations, where N is the number of interpolation points. Because basis functions are not explicitly used, the implementation is applicable to a wide class of interpolation kernels. Numerical examples involving generated data and measurements of formed sheet-metal parts are presented.     

CVD ZrO2‐Beschichtung von Fasern bei Normaldruck

Atmospheric pressure CVD of ZrO₂ on fibers Two different Chemical vapor deposition processes on fiberbundles (number of fibers a few thousand, diameter of the single fiber ≈10 µm) with zirconium dioxide at atmospheric pressure have been developed (AiF project 12783N): 1) ZrO₂ thin films on SiTiC fibers were grown by flame‐CVD using zirconium dipivaloylmethanate or acetylacetonate as precursors. The total deposition rate of 3·10^–5 mol·m^–2·s^–1 was achieved in a 4 cm long deposition zone. 2) In a new atmospheric pressure CVD process the deposition took place via hydrolysis of zirconium dipyvaloylmethanate in water vapor. The total deposition rate of 7·10^–6 mol·m^–2·s^–1 has been achieved in a 60 cm long pilot setup. This value allows to deposit continuously a 10 nm thick ZrO₂ films on fibers moving with velocity of 30 m/h. The deposition rate demonstrated in this work is the highest achieved so far for ZrO₂ CVD at atmospheric pressure.