Robustness of an aerobic metabolically vinyl chloride degrading bacterial enrichment culture

Degradation of the lower chlorinated ethenes is crucial to the application of natural attenuation or in situ bioremediation on chlorinated ethene contaminated sites. Recently, within mixtures of several chloroethenes as they can occur in contaminated groundwater inhibiting effects on aerobic chloroethene degradation have been shown. The current study demonstrated that metabolic vinyl chloride (VC) degradation by an enrichment culture originating from groundwater was not affected by an equimolar concentration (50 μM) of cis-1,2-dichloroethene (cDCE). Only cDCE concentrations at a ratio of 2.4:1 (initial cDCE to VC concentration) caused minor inhibition of VC degradation. Furthermore, the degradation of VC was not affected by the presence of trans-1,2-dichloroethene (tDCE), 1,1-dichloroethene (1,1-DCE), trichloroethene (TCE), and tetrachloroethene (PCE) in equimolar concentrations (50 μM). Only cDCE and tDCE were cometabolically degraded in small amounts. The VC-degrading culture demonstrated a broad pH tolerance from 5 to 9 with an optimum between 6 and 7. Results also showed that the culture could degrade VC concentrations up to 1,800 μM (110 mg/L).     

Coherent Phonon-Induced Modulation of Charge Transfer in 2D Hybrid Perovskites

Electron–phonon interactions play an essential role in charge transport and transfer processes in semiconductors. For most structures, tailoring electron–phonon interactions for specific functionality remains elusive. Here, it is shown that, in hybrid perovskites, coherent phonon modes can be used to manipulate charge transfer. In the 2D double perovskite, (AE2T)₂AgBiI₈ (AE2T: 5,5“-diylbis(amino-ethyl)-(2,2”-(2)thiophene)), the valence band maximum derived from the [Ag_0.5Bi_0.5I₄]^2– framework lies in close proximity to the AE2T-derived HOMO level, thereby forming a type-II heterostructure. During transient absorption spectroscopy, pulsed excitation creates sustained coherent phonon modes, which periodically modulate the associated electronic levels. Thus, the energy offset at the organic–inorganic interface also oscillates periodically, providing a unique opportunity for modulation of interfacial charge transfer. Density-functional theory corroborates the mechanism and identifies specific phonon modes as likely drivers of the coherent charge transfer. These observations are a striking example of how electron–phonon interactions can be used to manipulate fundamentally important charge and energy transfer processes in hybrid perovskites.     

Hybridization Networks of mRNA and Branched RNA Hybrids

Messenger RNA (mRNA) is emerging as an attractive biopolymer for therapy and vaccination. To become suitable for vaccination, mRNA is usually converted to a biomaterial, using cationic peptides, polymers or lipids. An alternative form of converting mRNA into a material is demonstrated that uses branched oligoribonucleotide hybrids with the ability to hybridize with one or more regions of the mRNA sequence. Two such hybrids with hexamer arms and adamantane tetraol as branching element were prepared by solution-phase synthesis. When a rabies mRNA was treated with the branched hybrids at 1 M NaCl concentration, biomaterials formed that contained both of the nucleic acids. These results show that branched oligoribonucleotides are an alternative to the often toxic reagents commonly used to formulate mRNA for medical applications.     

Magnetic field-driven induction of ZENK in the trigeminal system of pigeons (Columba livia)

Magnetoreception remains one of the few unsolved mysteries in sensory biology. The upper beak, which is innervated by the ophthalmic branch of the trigeminal nerve (V1), has been suggested to contain magnetic sensors based on ferromagnetic structures. Recently, its existence in pigeons has been seriously challenged by studies suggesting that the previously described iron-accumulations are macrophages, not magnetosensitive nerve endings. This raised the fundamental question of whether V1 is involved in magnetoreception in pigeons at all. We exposed pigeons to either a constantly changing magnetic field (CMF), to a zero magnetic field providing no magnetic information, or to CMF conditions after V1 was cut bilaterally. Using immediate early genes as a marker of neuronal responsiveness, we report that the trigeminal brainstem nuclei of pigeons, which receive V1 input, are activated under CMF conditions and that this neuronal activation disappears if the magnetic stimuli are removed or if V1 is cut. Our data suggest that the trigeminal system in pigeons is involved in processing magnetic field information and that V1 transmits this information from currently unknown, V1-associated magnetosensors to the brain.     

Effect of Ti,Nb, and Ti + Nb Coatings on the Bond Strength-Structure Relationship in Al/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Joints

There is a growing interest in metal-ceramic bonding for wide range of applications in electronic devices and high technology industry for fabrication of metal matrix composites and bonding of ceramic components to metals. The object of the work was to study the effect of Ti, Nb, and Ti + Nb thin films deposited by PVD method on alumina substrates on structure and bond strength properties of Al/Al₂O₃ joints. The joints were fabricated using the results of a wetting experiment and the sessile drop method at a temperature of 1223 K in a vacuum of 0.2 MPa for 30 min of contact. The structure of the metal/ceramic interface was investigated using scanning electron microscopy. The elemental distribution at the metal-ceramic interface was analyzed using energy dispersive x-ray spectroscopy. Transmission electron microscopy was also used to investigate some aspects of the metal/ceramic interface. The bond strength properties of joints were measured using shear test. The shear strength results demonstrated significant improvement of shear strength of Al/Al₂O₃ joints due to the application of Ti + Nb thin film on alumina substrate. Microstructural investigations of the interface indicated that Al/coating/Al₂O₃ couples have diffusion transition interface which influences the strengthening of these joints. A conclusion could be drawn that the presence of thin film layers changes the character of interaction and leads to the formation of new reaction products in the bonding layer.     

Effect of Bacterial Infection on Ghrelin Receptor Regulation in Periodontal Cells and Tissues

The effect of bacterial infection on the expression of growth hormone secretagogue receptor (GHS-R) was investigated in periodontal cells and tissues, and the actions of ghrelin were evaluated. GHS-R was assessed in periodontal tissues of rats with and without periodontitis. Human gingival fibroblasts (HGFs) were exposed to Fusobacterium nucleatum in the presence and absence of ghrelin. GHS-R expression was determined by real-time PCR and immunocytochemistry. Furthermore, wound healing, cell viability, proliferation, and migration were evaluated. GHS-R expression was significantly higher at periodontitis sites as compared to healthy sites in rat tissues. F. nucleatum significantly increased the GHS-R expression and protein level in HGFs. Moreover, ghrelin significantly abrogated the stimulatory effects of F. nucleatum on CCL2 and IL-6 expressions in HGFs and did not affect cell viability and proliferation significantly. Ghrelin stimulated while F. nucleatum decreased wound closure, probably due to reduced cell migration. Our results show original evidence that bacterial infection upregulates GHS-R in rat periodontal tissues and HGFs. Moreover, our study shows that ghrelin inhibited the proinflammatory actions of F. nucleatum on HGFs without interfering with cell viability and proliferation, suggesting that ghrelin and its receptor may act as a protective molecule during bacterial infection on periodontal cells.     

Development and characterization of inks for screen printing of glass solders for SOFCs

Glass ceramics are supposed to produce stable sealants between ceramic electrolyte and ferritic steel in planar SOFC stacks. The screen printing method is a suitable industrial process in order to produce layers with tailored height and width reproducibly. An appropriate suspension was developed for this application and improved by adjusting the additive composition. This study investigates the rheological behavior of screen printing inks and the corresponding topography of the printed layers. Rotary measurements were carried out to analyse the impact of shear rates on viscosity showing shear thinning behavior. In addition, oscillatory rheometry is performed to gain information about the viscoelastic properties of the slurries and to understand the internal structure of the developed inks. The viscoelasticity and the recovery behavior after shear loading are crucial for the topography of printed films. The principal investigations are executed on solvent-based suspensions, whereby the knowledge gained is used for a transfer to water-based systems allowing a more environmentally friendly handling.