Ultrasound-Assisted Preparation of Mo/ZSM-5 Zeolite Catalyst for Non-Oxidative Methane Dehydroaromatization

The activity and selectivity of Mo/ZSM-5, benchmarking catalyst for the non-oxidative dehydroaromatization of methane, strongly depend on the cluster size, spatial distribution, and chemical environment of the Mo-based active sites. This study discloses the use of an ultrasound-assisted ion-exchange (US-IE) technique as an alternative Mo/ZSM-5 synthesis procedure in order to promote metal dispersion along the zeolite framework. For this purpose, a plate transducer (91.8 kHz) is employed to transmit the ultrasonic irradiation (US) into the ion-exchange reactor. The physico-chemical properties and catalytic activity of samples prepared under the said irradiation procedure and traditional impregnation (IWI) method are critically evaluated. Characterization results suggest that US neither affects the crystalline structure nor the particle size of the parent zeolite. However, US-IE promotes molybdenum species dispersion, avoids clustering at the external fresh zeolite surface and enhances molybdate species anchoring to the zeolite framework with respect to IWI. Despite the improved metal dispersion, the catalytic activity between catalysts synthesized by US-IE and IWI is comparable. This suggests that the sole initial dispersion enhancement does not suffice to boost the catalyst productivity and further actions such ZSM-5 support and catalyst pre-conditioning are required. Nevertheless, the successful implementation of US-IE and the resulting metal dispersion enhancement pave the way toward the application of this technique to the synthesis of other dispersed catalysts and materials of interest

Expansion properties of Alginate beads as cell carrier in the fluidized bed bioartificial liver

The homogeneous expansion behaviour of liquid-fluidized beds is exploited in various fields such as minerals engineering and biotechnology. Innovative fluidized bed bioreactor concepts have been also explored for applications as bioartificial organs, particularly the bioartificial liver (1). It has been shown that the fluidized bed bioreactor constituted of alginate beads hosting liver cells is one of the promising solution to a bioartificial liver. Compared to other solutions, fluidization of alginate beads containing the cells does not suffer from the severe limitations to mass transfer between the beads and the perfusion medium. In the present work, appropriate alginate beads were prepared by the alginate drop gelation in calcium chloride. The beads were characterized in terms of size distribution and density. Sauter mean diameter of 813 m and density of 1020 kg/m3 were obtained. The latter shows a value very close to usual perfusion fluid, which required also careful evaluation of the liquid properties. Expansion properties were evaluated for free alginate beads (i.e. without hepatic cells) using saline solutions as fluidization medium. Bed expansions have been conducted in a small-size 1-cm diameter column used for perfusion in in vitro experiments as well as in a bigger 10-cm diameter column close to human size bioreactor. Velocity-voidage plots are reported and elaborated in terms of Richardson-Zaki parameters, showing the effect of walls and the different distributor. ACKNOLEDGEMENTS The financial support of the European Union through the Project FP7-PEOPLE-2012-ITN “Training network for developing innovative bioartificial devices for treatment of kidney and liver disease” is gratefully acknowledged. REFERENCES Gautier A., Carpentier B., Dufresne M., Vu Dinh Q., Paullier P., Legallais C. Impact of alginate type and bead diameter on mass transfers and the metabolic activities of encapsulated C3A cells in bioartificial liver applications. European Cells and Materials 2011, 21:94-106

Synthesis of purine-based ionic liquids and their applications

Bio-based ionic liquids (ILs) are being increasingly sought after, as they are more sustainable and eco-friendly. Purines are the most widely distributed, naturally occurring N-heterocycles, but their low water-solubility limits their application. In this work, four purines (theobromine, theophylline, xanthine, and uric acid) were combined with the cation tetrabutylammonium to synthesize bio-based ILs. The physico-chemical properties of the purine-based ILs were characterized, including their melting and decomposition temperatures and water-solubility. The ecotoxicity against the microalgae Raphidocelis subcapitata was also determined. The ILs show good thermal stability (>457 K) and an aqueous solubility enhancement ranging from 53- to 870-fold, in comparison to their respective purine percursors, unlocking new prospects for their application where aqueous solutions are demanded. The ecotoxicity of these ILs seems to be dominated by the cation, and it is similar to chloride-based IL, emphasizing that the use of natural anions does not necessarily translate to more benign ILs. The application of the novel ILs in the formation of aqueous biphasic systems (ABS), and as solubility enhancers, was also evaluated. The ILs were able to form ABS with sodium sulfate and tripotassium citrate salts. The development of thermoresponsive ABS, using sodium sulfate as a salting-out agent, was accomplished, with the ILs having different thermosensitivities. In addition, the purine-based ILs acted as solubility enhancers of ferulic acid in aqueous solution.publishe

More Than Just Tumor Destruction: Immunomodulation by Thermal Ablation of Cancer

Over the past decades, thermoablative techniques for the therapy of localized tumors have gained importance in the treatment of patients not eligible for surgical resection. Anecdotal reports have described spontaneous distant tumor regression after thermal ablation, indicating a possible involvement of the immune system, hence an induction of antitumor immunity after thermoinduced therapy. In recent years, a growing body of evidence for modulation of both adaptive and innate immunity, as well as for the induction of danger signals through thermoablation, has emerged. Induced immune responses, however, are mostly weak and not sufficient for the complete eradication of established tumors or durable prevention of disease progression, and combination therapies with immunomodulating drugs are being evaluated with promising results. This article aims to summarize published findings on immune modulation through radiofrequency ablation, cryoablation, microwave ablation therapy, high-intensity focused ultrasound, and laser-induced thermotherapy

Differential permissivity of human cerebrovascular endothelial cells to enterovirus infection and specificities of enterovirus 71 in crossing an in vitro model of human blood brain barrier

Human cerebral microvascular endothelial cells (hCMEC/D3 cell line) form a steady polarized barrier when cultured in vitro on a permeable membrane. Their susceptibility to enterovirus (EV) strains was analysed to investigate how these viruses may cross the blood-brain barrier. A sample of 88 virus strains was selected on phylogenetic features among 44 epidemiologically relevant types of the four EV species A-D. The EV-A71 genome was replicated at substantial rates while the infectious virus was released at extremely low but sustained rates at both barrier sides for at least 4 days. EV-A71 antigens were detected in a limited number of cells. The properties of the endothelial barrier (structure and permeability) remained intact throughout infection. The chronic EV-A71 infection was in sharp contrast with the productive infection of cytolytic EVs (e.g. echoviruses 6 and 30). The hCMEC/D3 barriers infected with the latter EVs exhibited elevated proportions of apoptotic and necrotic cells, which resulted in major injuries to the endothelial barriers with dramatic increase of paracellular permeability and virus crossing to the abluminal side. The following intracellular rearrangements were also seen: early destruction of the actin cytoskeleton, remodelling of intracellular membranes, and reorganization of the mitochondrion network in a small cluster near the perinuclear space

Characterization of Group B Streptococcus strains isolated from neonatal invasive diseases in Belgium, 2018.

peer reviewedIntroduction Despite advances in preventive strategies, Group B Streptococcal(GBS) disease is still a leading cause of severe neonatal infections. The Belgian National Reference Centre (NRC) routinely performs surveillances of GBS invasive strains isolated in Belgium. Methods All GBS strains isolated from neonatal invasive diseases sent on a voluntary-base to the NRC during the year 2018 were characterized: capsular polysaccharide (CPS)-typing by agglutination and/or PCR, pili-typing with PCR, antimicrobial susceptibility testing, and detection of resistance genes with PCR. Results A total of 58 GBS strains isolated from neonatal invasive diseases were available: 33 and 27 from Early-Onset (EOD) and Late-Onset Diseases (LOD). The ratio EOD/LOD is of 1.22. Overall, CPS-type III was predominant (46.9% in EOD and 91.3% in LOD cases) followed by Ia, V, Ib, IV, IX and II in EOD (21.9%, 9.4%, 6.2%, 3.1%, 3.1%, 0.1%). All strains were susceptible to penicillin. Rate of resistance to macrolides and lincosamides was 28%. The main resistant gene detected among these resistant isolates was the ErmB gene (81,3%). About pili-typing, all strains harboured one of the PI-2 variants alone or in combination: the predominant type was PI1, PI2a (39.2%) followed by PI1, PI2b (29.4%), PI2a (21.6%) and PI2b (9.8%). Bacteriemia was the predominant manifestation with meningitis in 12% of EOD and 40% of LOD cases. Conclusion The burden of neonatal GBS diseases remains important and prevention strategies need to be improved. CPS-type and pili-type distributions, and resistance rate to macrolides/lincosamides are quite similar to European/North American observations done during the last decade

Evaluation of Whole-Genome Sequencing combined with a bioinformatics tool for the complete characterization of Streptococcus agalactiae infection

peer reviewedBackground: Our aim was to evaluate the Whole-Genome Sequencing (WGS), as a new tool, in order to implement the method within the activities of the Belgian National Reference Centre Streptococcus agalactiae (NRC). The analysis of the bacterial genome by WGS could replace some current standard methods used at the NRC, unifying laboratory workflow, diminishing workload, enhancing molecular surveillance. Methods: To determine the reliability of the WGS, the results were compared with those obtained by the standard methods used by the NRC (multiplex PCRs and MLST). The raw sequence data from WGS were analyzed with the bioinformatics tool "WGS-typer" (Hedera22, Liège, Belgium), specially designed for the NRC needs. 37 strains isolated from vaginal colonization, or invasive infections in adults and infants were selected for their varied characteristics from the NRC collection. Capsular serotype, pili proteins genes, macrolides/lincosamides/streptogramins (MLS) resistance genes and sequence types were determined by both approaches. Results: Regarding capsular serotype and pili protein genes, the results reported by conventional PCR methods were perfectly confirmed by the WGS (100% concordance). However, for MLS resistance genes and sequence types, the comparison highlights one and three discrepancies respectively. A new sequence type 1655 was listed in the PUBMLST database thanks to this research. Conclusion: WGS is a promising approach that can compete with the conventional methods currently used in laboratories. Indeed, this technology allows, at lower costs and workload, a complete characterization of the GBS and a huge concordance between WGS and conventional methods has been observed

Economic Evaluation of Eight Regional Scenarios for the Deployment of Carbon Capture, Use and Storage in Southern and Eastern Europe to 2050

During the three-year EU-funded STRATEGY CCUS project [1] [3] (2019-2022), Carbon Capture, Use and Storage (CCUS) scenarios formulated for eight regions in Southern and Eastern Europe were developed and economically evaluated up to 2050. These regional CCUS scenarios are based on both the performances of local industries in operation and for which CCUS is a relevant mitigation alternative, as well as the regional storage capacities known to date. The eight CCUS regional scenarios are in: 1) Paris basin and 2) Rhône Valley in France, 3) Ebro basin in Spain, 4) Lusitanian basin in Portugal, 5) Northern Croatia, 6) Upper Silesia in Poland, 7) West Macedonian area in Greece and 8) Galati area in Romania. They cover an extensive and original portfolio of possible CCUS business models. While some scenarios assume that the captured CO2 is used for synthetic methane or chemical production, in most cases the captured CO2 is sent to CO2 storage facilities. The biogenic CO2 captured is monitored and its storage time in new uses watched. The economic evaluation considers the negative CO2 emissions resulting from the long-term storage or use of captured biogenic CO2. This paper compares the economic Key Performance Indicators (KPIs) of these eight CCUS business cases with the carbon penalties that would have been charged to the same industries to remain in compliance with the European Union - Emissions Trading System (EU ETS). The calculated KPIs mainly reflect the costs and revenues expressed in euros per ton of CO2 avoided or removed for the whole regional scenario until 2050