Capturing CO2 by ceria and ceria-zirconia nanomaterials of different origin.

Ceria and ceria-zirconia nanomaterials of different origin were studied in order to elucidate the role of their structural and textural characteristics in controlling the performance towards CO2 capture. Two commercial cerias and two home-prepared samples, CeO2 and CeO2-ZrO2 (75% CeO2) mixed oxide, were investigated. The samples were characterized by a number of analytical techniques including XRD, TEM, N2-adsorption, XPS, H2-TPR, Raman and FTIR spectroscopy. Static and dynamic CO2 adsorption experiments were applied to assess the CO2 capture performance. The type of surface species formed and their thermal stability were evaluated by in situ FTIR spectroscopy and CO2-TPD analysis. The two commercial ceria samples possessed similar structural and textural characteristics, formed the same types of carbonate-like surface species upon CO2 adsorption and, consequently, demonstrated almost identical CO2 capture performance under both static and dynamic conditions. The thermal stability of the adsorbed species increased in the order bidentate (B) carbonates, hydrogen carbonates (HC) and tridentate carbonates (T-III, T-II, T-I). Reduction of CeO2 increased the relative amount of the most strongly bonded T-I tridentate carbonates. Preadsorbed water led to hydroxylation and enhanced formation of hydrogen carbonates. Although the synthesized CeO2 sample had a higher surface area (by 30%) it showed a disadvantageous long mass transfer zone in the CO2-adsorption breakthrough curves. Because of its complex pore structure, this sample probably experiences severe intraparticle CO2 diffusion resistance. Having the same surface area as the synthesized CeO2, the mixed CeO2-ZrO2 oxide exhibited the highest CO2 capture capacity of 136 µmol g-1 under dynamic conditions. This was related to the highest concentration of CO2 adsorption sites (including defects) on this sample. The CeO2-ZrO2 system showed the lowest sensitivity to the presence of water vapor in the gas stream due to the lack of dissociative water adsorption on this material.

Preparation and characterizations of EGDE crosslinked chitosan electrospun membranes.

Composite Crosslinked nanofibrous membranes of chitosan, ethylene glycol diglycidyl ether (EGDE) and polyethylene oxide was successfully prepared with bead free morphology via electrospinning technique followed by heat mediated chemical crosslinking. Architectural stability of nanofiber mat in aqueous medium was achieved by chemical crosslinking of only 1% EGDE, and tensile strength tests revealed that increasing EGDE content has considerably enhance the elastic modulus of nanofibers. The structure, morphology and mechanical properties of nanofibers were characterized by Attenuated Total Reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) and Instron machine, respectively. Skin fibroblasts and endothelial cells showed good attachment, proliferation and viability on crosslinked electrospun membranes. The results indicate a good biocompatibility and non-toxic nature of the resulted membrane.

DefibViz: a visualization tool for the assessment of electrode parameters on transthoracic defibrillation thresholds.

DefibViz is a software application developed for defibrillation simulation and visualization. It exploits both surface techniques and methods for the interactive exploration of volumetric datasets for the analysis of transthoracic defibrillation simulation results. DefibViz\ has a graphical user interface for the specification of the shape, size, position, and applied voltage of a defibrillator's electrodes. An option is provided for using 3-D slice plane widgets, which operate on the volumetric datasets, such that the distribution of the voltage gradient induced by an electric shock can be visually inspected in various tissues throughout the myocardium and torso. One goal of DefibViz is to enhance understanding of how electrode parameters relate to the change of the voltage gradient distribution throughout the heart, which may help lead to optimal defibrillator design. DefibViz; is significant, in that, it is built by using an open-source graphics and visualization framework providing a platform for subsequent modifiability and extensibility. Moreover, it integrates simulation and visualization techniques, which previously required the running of several independent software executables, into an enhanced, seamless, and comprehensive software application.

Monoclonal antibodies reacting against capacitated but not with freshly ejaculated boar spermatozoa.

PROBLEM: The involvement of individual sperm proteins in differentiation of antigenically specific and functionally defined regions on sperm membrane has not yet been completely elucidated. METHOD: BALB/c mice were immunized with live capacitated boar spermatozoa and used for production of monoclonal antibodies (MAbs). ELISA, IIF, SDS-PAGE, IVF, and cytologic methods were used for selection and biological characterization of MAbs as well as for identification of corresponding antigens. RESULTS: MAb1F10, MAb2E2, and MAb4B12 react with antigens in the acrosome portion of live capacitated spermatozoa, MAb 1F10 reacted with human sperm cells along with those from bull, ram, mouse, dog, whereas MAb2E2--with mouse's spermatozoa and MAB4B12-with bull's, mouse's, and dog's spermatozoa. Some glycolytic enzymes seemed to reduce mildly the reactions of the MAbs with enzyme treated sperm cells; proteolytic enzymes eliminated the binding of MAbs to the sperm acrosome. These MAbs have no sperm agglutinating and/or sperm-immobilizing activities and reduced the number of spermatozoa binding to zona pellucida. CONCLUSIONS: MAb1F10, MAb2E2, and MAb4B12 seemed to recognize membrane associated antigens with potential role in the initial stages of fertilization, specific for capacitated but not for freshly ejaculated spermatozoa.