Impact of silica structure of copper and iron-containing SBA-15 and SBA-16 materials on toluene oxidation

Copper and iron modified SBA-15 and SBA-16 materials were prepared by incipient wetness impregnation technique and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 physisorption, temperature-programmed reduction (TPR-TGA), UV-Vis diffuse reflectance and Mössbauer spectroscopy. Formation of finely dispersed copper and iron-oxide species was observed on both supports, whereas copper ferrite could be evidenced only on SBA-15. It was found that the structural and surface properties of the mesoporous supports determine the type of formed metal oxides, their dispersion, reducibility and the catalytic activity in total oxidation of toluene. On SBA-16 support penetration of metal salt into the bimodal channel system is hindered therefore separate copper- and iron-oxide phases are formed on the outer surface of catalysts. The catalytic activity and stability are lower due to the easier agglomeration of particles. On SBA-15 support finely dispersed metal-oxides can be found in the mesoporous channels. Their interaction is favored to form bimetallic phases enhancing the catalytic activity and stability in total oxidation of toluene

Chronic Lymphocytic Leukemia — Microenvironment and B Cells

Chronic lymphocytic leukemia (CLL) has been considered as an accumulative disease deriving from defects in apoptosis, but recent studies showed that CLL is a dynamic process in which monoclonal B cells proliferate within pseudofollicular proliferation centers. Microenvironmental interactions are essential for the survival and proliferation of CLL cells. The cell traffic between blood and secondary lymphoid tissues is controlled by tissue-specific chemokines and their specific receptors on B lymphocytes. Interstitial cell migration and adhesion events, predisposed by activational stimuli, determine CLL cell localization. Stimulation through the B cell receptor plays an important role in the expansion of the malignant clone in CLL. B cell receptors become activated either in an antigen-dependent or in an antigen-independent fashion in the secondary lymphatic tissues. However, low expression of the BCR correlates with reduced induction of protein tyrosine kinase activity and defective intracellular calcium mobilization and tyrosine phosphorylation. In contrast to normal B cells, leukemic cells are poor antigen presenting cells. This is due to the fact that leukemic cells have a reduced expression of costimulatory molecules and defects in the formation of immunological synapse with T cells. Increased surface expression of the costimulatory molecules on CLL cells correlates with their proliferation. At present, conventional treatments are not directed to interactions between CLL cells and their microenvironment, which is probably one of the reasons why, despite the significant progress in treatment, the disease still remains incurable. In this regard, identifying key biomarkers of intercellular interactions of neoplastic CLL population in comparison with clinical laboratory abnormalities in CLL enable clarification of essential processes in the development of the disease, and can be the basis for stratifying patient groups in order to optimize therapeutic approaches, which will make them relevant and promising

Glycerol acetylation on mesoporous KIL-2 supported sulphated zirconia catalysts

Zirconia nanomaterials were prepared by impregnation of KIL-2 type silica with 4, 8 and 12 wt.% ZrO2 and were modified by sulphate groups in order to vary the type and strength of acidity. Samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and N2 physisorption methods. Acidic properties of adsorbed pyridine were investigated by FT-IR spectroscopy. The catalytic performance of ZrKIL-2 and SO4 2−/ZrKIL-2 in glycerol esterification with acetic acid was studied and compared to that of pure zirconia varieties. It was found that silica-supported zirconia samples are more active than pure zirconia ones. With increasing ZrO2 content, KIL-2-supported catalysts showed increasing catalytic activity and selectivity in producing valuable fuel additives, di- and triacetyl glycerols. Sulphated analogues showed even higher activity and selectivity compared to non-sulphated ones due to their strong Brönsted acidity

Solid-state encapsulation of Ag and sulfadiazine on zeolite Y carrier

Hypothesis: A new simplified procedure for encapsulation of antibacterial silver nanoparticles by Solid-state Ion Exchange (SSIE) procedure over zeolite Y, followed by deposition of sulfadiazine (SD) by dry mixing was examined for the preparation of topical antibacterial formulations. The ion-exchange and adsorptive properties of the zeolite matrix were utilized for the bactericidal Ag deposition and loading of antibiotic sulfadiazine. Experiments: Assessment of the encapsulation efficiency of both active components loaded by solid and liquid deposition methods was made by X-ray diffraction, TEM, FT-IR spectroscopy and thermogravimetric analysis (TGA). SD release kinetics was also determined. Findings: Sustained delivery of sulfadiazine has been observed from the Ag-modified zeolites compared to the parent HY material. It was found that if SD was loaded in solution, part of the zeolite silver ions was released and interacted with SD, forming AgSD. By solid-state SD deposition, the reaction between the drug and the silver was restricted within the limits of inter-atomic interaction, and total but prolonged drug release occurred. © 2015 Published by Elsevier Inc