Mesopore-modified mordenites as catalysts for catalytic pyrolysis of biomass and cracking of vacuum gasoil processes

[EN] Mesopore-modified mordenite zeolitic materials with different Si/Al ratios have been repared and tested in the biomass pyrolysis and catalytic cracking of vacuum gasoil. Alkaline treatment was carried out to generate mesoporosity. Severity of alkaline treatment was found to be of paramount importance to tune the generated mesoporosity, while it significantly affected the crystallinity of treated mordenites. It was moreover observed that the alkaline treatment selectively extracted Si decreasing the Si/Al ratio of treated samples. Catalytic activity of parent and alkaline treated mordenites was studied in the pyrolysis of biomass. All zeolitic based materials produced less amounts of bio-oil but of better quality (lowering the oxygen content from ∼40% to as much as 21%) as compared to the non-catalytic pyrolysis experiments. On the other hand, it was found that the combination of mesopore formation and high surface area after alkaline treatment of the mordenite with a high Si/Al ratio resulted in the enhancement of its catalytic activity, despite the reduction of its acidity. The increment of the decarboxylation and dehydration reactions, combined with a reduction of carbon deposition on the catalyst, resulted in a remarkable decrease in the oxygen content in the organic fraction and therefore, resulted in a superior quality liquid product. Alkaline treated mordenites were additionally acid treated targeting dealumination and removal of the extra framework debris, thus generating mesopore-modified mordenite samples with stronger acid sites and higher total acidity, as candidate catalysts for catalytic cracking of vacuum gasoil. Desilicated and especially desilicated and dealuminated mordenites exhibited the highest activity and selectivity towards LCO with the best olefinicity in gases and higher bottoms conversion. Therefore, an optimized desilicated dealuminated mordenite additive could be an interesting candidate as a component of the FCC catalyst for a high LCO yield.The financial support of this work by the ACENET COMMON INITIATIVE HECABIO: "HEterogeneous CAtalysis for the Conversion of Solid BIOmass into Renewable Fuels and Chemicals" Project ACE.07.026 is gratefully acknowledged.Stefanidis, S.; Kalogiannis, K.; Iliopoulou, EF.; Lappas, AA.; Martínez Triguero, LJ.; Navarro Ruiz, MT.; Chica, A.... (2013). Mesopore-modified mordenites as catalysts for catalytic pyrolysis of biomass and cracking of vacuum gasoil processes. Green Chemistry. 15(6):1647-1658. doi:10.1039/c3gc40161hS1647165815

Human CD34+ CD133+ Hematopoietic Stem Cells Cultured with Growth Factors Including Angptl5 Efficiently Engraft Adult NOD-SCID Il2rγ−/− (NSG) Mice

Increasing demand for human hematopoietic stem cells (HSCs) in clinical and research applications necessitates expansion of HSCs in vitro. Before these cells can be used they must be carefully evaluated to assess their stem cell activity. Here, we expanded cord blood CD34+ CD133+ cells in a defined medium containing angiopoietin like 5 and insulin-like growth factor binding protein 2 and evaluated the cells for stem cell activity in NOD-SCID Il2rg−/− (NSG) mice by multi-lineage engraftment, long term reconstitution, limiting dilution and serial reconstitution. The phenotype of expanded cells was characterized by flow cytometry during the course of expansion and following engraftment in mice. We show that the SCID repopulating activity resides in the CD34+ CD133+ fraction of expanded cells and that CD34+ CD133+ cell number correlates with SCID repopulating activity before and after culture. The expanded cells mediate long-term hematopoiesis and serial reconstitution in NSG mice. Furthermore, they efficiently reconstitute not only neonate but also adult NSG recipients, generating human blood cell populations similar to those reported in mice reconstituted with uncultured human HSCs. These findings suggest an expansion of long term HSCs in our culture and show that expression of CD34 and CD133 serves as a marker for HSC activity in human cord blood cell cultures. The ability to expand human HSCs in vitro should facilitate clinical use of HSCs and large-scale construction of humanized mice from the same donor for research applications.Singapore-MIT Alliance for Research and Technology ( Infectious Diseases research grant

Membrane-Bound IL-21 Promotes Sustained Ex Vivo Proliferation of Human Natural Killer Cells

NK cells have therapeutic potential for a wide variety of human malignancies. However, because NK cells expand poorly in vitro, have limited life spans in vivo, and represent a small fraction of peripheral white blood cells, obtaining sufficient cell numbers is the major obstacle for NK-cell immunotherapy. Genetically-engineered artificial antigen-presenting cells (aAPCs) expressing membrane-bound IL-15 (mbIL15) have been used to propagate clinical-grade NK cells for human trials of adoptive immunotherapy, but ex vivo proliferation has been limited by telomere shortening. We developed K562-based aAPCs with membrane-bound IL-21 (mbIL21) and assessed their ability to support human NK-cell proliferation. In contrast to mbIL15, mbIL21-expressing aAPCs promoted log-phase NK cell expansion without evidence of senescence for up to 6 weeks of culture. By day 21, parallel expansion of NK cells from 22 donors demonstrated a mean 47,967-fold expansion (median 31,747) when co-cultured with aAPCs expressing mbIL21 compared to 825-fold expansion (median 325) with mbIL15. Despite the significant increase in proliferation, mbIL21-expanded NK cells also showed a significant increase in telomere length compared to freshly obtained NK cells, suggesting a possible mechanism for their sustained proliferation. NK cells expanded with mbIL21 were similar in phenotype and cytotoxicity to those expanded with mbIL15, with retained donor KIR repertoires and high expression of NCRs, CD16, and NKG2D, but had superior cytokine secretion. The mbIL21-expanded NK cells showed increased transcription of the activating receptor CD160, but otherwise had remarkably similar mRNA expression profiles of the 96 genes assessed. mbIL21-expanded NK cells had significant cytotoxicity against all tumor cell lines tested, retained responsiveness to inhibitory KIR ligands, and demonstrated enhanced killing via antibody-dependent cell cytotoxicity. Thus, aAPCs expressing mbIL21 promote improved proliferation of human NK cells with longer telomeres and less senescence, supporting their clinical use in propagating NK cells for adoptive immunotherapy