Quaternäre Metall/Metalloxid‐Katalysatoren als Wandkatalysatoren in Mikroreaktoren für Power‐to‐Gas‐Applikationen mittels kombinatorischer Hochdurchsatzmethoden

Catalysts of quaternary composition have been prepared and tested for the Sabatier process. For catalyst syntheses the following techniques have been used: sol‐gel methods, wet impregnation and incipient wetness impregnation. The Sabatier reaction was carried out at temperatures between 520 K and 670 K, pressures of 15 bar and 30 bar using a mixture H₂:CO₂ of 4:1. Activity screening of the microscale wall catalysts was performed by a custom‐built 10‐fold parallel gas‐flow microreactor setup in sequential operating mode. To analyze the gas phase compositions GC‐FID was used.     

Synthesis of Long-Chain β-Lactones and Their Antibacterial Activities against Pathogenic Mycobacteria

In the quest for new antibacterial agents, a series of novel long- and medium-chain mono- and disubstituted β-lactones was developed. Their activity against three pathogenic mycobacteria—M. abscessus, M. marinum, and M. tuberculosis—was assessed by the resazurin microtiter assay (REMA). Among the 16 β-lactones synthesized, only 3-hexadecyloxetan-2-one (VM005) exhibited promising activity against M. abscessus, whereas most of the β-lactones showed interesting activities against M. marinum, similar to that of the classical antibiotic, isoniazid. Regarding M. tuberculosis, six compounds were found to be active against this mycobacterium, with β-lactone VM008 [trans-(Z)-3-(hexadec-7-en-1-yl)-4-propyloxetan-2-one] being the best growth inhibitor. The promising antibacterial activities of the best compounds in this series suggest that these molecules may serve as leads for the development of much more efficient antimycobacterial agents.     

Sulfonylguanidine Derivatives as Potential Antimelanoma Agents

Sulfonylguanidines are interesting bioactive compounds with a broad range of applications in the treatment of different pathologies. 2-Aminobenzazole-based structures are well employed in the development of new anticancer drugs. Two series of novel N-benzazol-2-yl-N′-sulfonyl guanidine derivatives were synthesized with the sulfonylguanidine in either an extra- or intracyclic frame. They were evaluated for their antiproliferative activity against malignant melanoma tumor cells, thus allowing structure-activity relationships to be defined. Additionally, NCI-60 screening was performed for the best analogue to study its efficiency against a panel of other cancer cell lines. The stability profile of this promising compound was then validated. During the synthetic process, an unexpected new deamidination of the sulfonylguanidine towards sulfonamide function was also identified.     

Synthesis,characterization and rheological properties of multiblock associative copolymers by RAFT technique

Polymer Bulletin - Preparation of associating multiblock copolymer electrolytes mediated by radical addition–fragmentation chain transfer (RAFT) technique has been evaluated and reported in...     

Micro molecular tagging velocimetry for analysis of gas flows in mini and micro systems

A new micro molecular tagging velocimetry (μMTV) setup has been developed to analyze velocity fields in confined internal gas flows. MTV is a little-intrusive velocimetry technique. It relies on the properties of molecular tracers which can experience relatively long lifetime luminescence once excited by a laser beam with an appropriate wavelength. The technique has been validated for acetone seeded flows of argon inside a 1 mm depth rectangular minichannel, with a multilayer design offering two optical accesses. Velocity profiles have been obtained using a specific data reduction process, with a resolution in the order of 15 μm. The experimental data are compared to theoretical velocity profiles of compressible pressure-driven flows. A good agreement is observed, except close to the walls, where the accuracy would still need to be improved. Following these first results obtained at atmospheric pressure, the influence of pressure on the luminescence intensity of acetone molecules is analyzed. The obtained data lead to a discussion of MTV applicability to rarefied flows and its possible use for a direct measurement of velocity slip at the channel walls.     

Metallocenyl 7-ACA Conjugates: Antibacterial Activity Studies and Atomic-Resolution X-ray Crystal Structure with CTX-M β-Lactamase

The conjugation of organometallic groups to current β-lactam antibiotics is a field of increasing study due to the ability of certain organometallic groups to enhance the antibiotic potency of these drugs. Herein, we report the antibacterial properties of two metallocenyl (ferrocenyl and ruthenocenyl) 7-aminocephalosporanic acid (7-ACA) antibiotic conjugates. Continuing a trend we found in our previous studies, the ruthenocenyl conjugate showed greater antibacterial activity than its ferrocenyl counterpart. Compared with the previously published 7-aminodesacetoxycephalosporanic acid (7-ADCA) conjugates, the 3-acetyloxymethyl group significantly improved the compounds’ activity. Furthermore, the Rc-7-ACA compound was more active against clinical Staphylococcus aureus isolates than the ampicillin reference. Noticeably, neither of the two new compounds showed an undesirable toxic effect in HeLa and L929 cells at the concentrations at which they displayed strong antibacterial effects. The antibacterial activity of the two metallocenyl 7-ACA derivatives was further confirmed by scanning electron microscopy (SEM). SEM micrographs showed that bacteria treated with metallocenyl 7-ACA derivatives feature cell wall damage and morphology changes. Using a CTX-M-14 β-lactamase competition assay based on nitrocefin hydrolysis, we showed that the Rc-7-ACA bound more favorably to CTX-M-14 than its ferrocenyl counterpart, again confirming the superiority of the ruthenocenyl moiety over the ferrocenyl one in interacting with proteins. We also report a 1.47 Å resolution crystal structure of Rc-7-ACA in complex with the CTX-M-14 E166A mutant, an enzyme sharing a similar active site configuration with penicillin-binding proteins, the molecular target of β-lactam antibiotics. These results strengthen the case for the antibacterial utility of the Rc and Fc groups.     

Nonhydrolyzable Heptose Bis- and Monophosphate Analogues Modulate Pro-inflammatory TIFA-NF-κB Signaling

d -Glycero-d -manno-heptose-1β,7-bisphosphate (HBP) and d -glycero-d -manno-heptose-1β-phosphate (H1P) are bacterial metabolites that were recently shown to stimulate inflammatory responses in host cells through the activation of the TIFA-dependent NF-κB pathway. To better understand structure-based activity in relation to this process, a family of nonhydrolyzable phosphonate analogues of HBP and H1P was synthesized. The inflammation modulation by which these molecules induce the TIFA-NF-κB signal axis was evaluated in vivo at a low-nanomolar concentration (6 nM) and compared to that of the natural metabolites. Our data showed that three phosphonate analogues had similar stimulatory activity to HBP, whereas two phosphonates antagonized HBP-induced TIFA-NF-κB signaling. These results open new horizons for the design of pro-inflammatory and innate immune modulators that could be used as vaccine adjuvant.