Effects of Na, Cu, Ni and Co Modifications on the Activity and Characteristics of Rh/Al2O3 Catalysts for NO Reduction

This study used different metals to modify Rh/Al₂O₃ catalysts for NO reduction in a simulated waste incineration flue gas containing 6% O₂. The characteristics of the modified catalysts were analyzed using BET, TEM and XRD. The results of the experiment reveal that Na addition can significantly affect the properties of Rh/Al₂O₃ catalysts on the BET surface area and Rh metal dispersion. Furthermore, Na addition was found to significantly enhance the NO conversion of Rh/Al₂O₃ at 250–350 °C. On the contrary, Cu, Ni, and Co addition was found to have slight suppression effects.     

Photocatalytic mineralisation of organic compounds: a comparison of flame-made TiO2 catalysts

A comparative photocatalytic analysis was carried out on TiO₂ made in a Flame Spray Pyrolysis (FSP) process and flame-made Degussa P25. Both have similar crystallinity, phase composition, phase segregation and a non-porous surface. Hence comparison was made based on their difference in specific surface area, organic adsorption and the amount of OH• generated upon illumination. The photocatalytic activity tests were carried out using the following series of organic compounds: sucrose, glucose, fructose, maleic acid, glyoxylic acid, oxalic acid, isobutyric acid, phenol and methanol. FSP-made TiO₂ outperformed P25 for saccharides mineralisation, while for phenol and methanol mineralisation P25 was better than FSP-made TiO₂. Similar mineralisation rates were observed for both FSP-made and P25 TiO₂ for the mineralisation of carboxylic acids. This shows that the relative performance of the photocatalysts depends on the type of organic compounds to be degraded. The high surface area and possibly a more efficient interfacial charge transfer of FSP-made TiO₂ provided an efficient pathway for saccharides mineralisation. As for phenol and methanol, the mineralisation rates were higher when using P25 due to the greater amount of OH• radicals generated by this photocatalyst. The fast mineralisation rates of carboxylic acids made degradation of these organic compounds to be less affected by the TiO₂ photocatalyst properties and conditions tested in this work.     

Rituximab chimeric anti-CD20 monoclonal antibody therapy for relapsed indolent lymphoma: half of patients respond to a four-dose treatment program

PURPOSE: The CD20 antigen is expressed on more than 90% of B-cell lymphomas. It is appealing for targeted therapy, because it does not shed or modulate. A chimeric monoclonal antibody more effectively mediates host effector functions and is itself less immunogenic than are murine antibodies. PATIENTS AND METHODS: This was a multiinstitutional trial of the chimeric anti-CD20 antibody, IDEC-C2B8. Patients with relapsed low grade or follicular lymphoma received an outpatient treatment course of IDEC-C2B8 375 mg/m2 intravenously weekly for four doses. RESULTS: From 31 centers, 166 patients were entered. Of this intent-to-treat group, 48% responded. With a median follow-up duration of 11.8 months, the projected median time to progression for responders is 13.0 months. Serum antibody levels were sustained longer after the fourth infusion than after the first, and were higher in responders and in patients with lower tumor burden. The majority of adverse events occurred during the first infusion and were grade 1 or 2; fever and chills were the most common events. Only 12% of patients had grade 3 and 3% grade 4 toxicities. A human antichimeric antibody was detected in only one patient. CONCLUSION: The response rate of 48% with IDEC-C2B8 is comparable to results with single-agent cytotoxic chemotherapy. Toxicity was mild. Attention needs to be paid to the rate of antibody infusion, with titration according to toxicity. Further investigation of this agent is warranted, including its use in conjunction with standard chemotherapy.     

Hierarchical clustering of mixed data based on distance hierarchy

Data clustering is an important data mining technique which partitions data according to some similarity criterion. Abundant algorithms have been proposed for clustering numerical data and some recent research tackles the problem of clustering categorical or mixed data. Unlike the subtraction scheme used for numerical attributes, there is no standard for measuring distance between categorical values. In this article, we propose a distance representation scheme, distance hierarchy, which facilitates expressing the similarity between categorical values and also unifies distance measuring of numerical and categorical values. We then apply the scheme to mixed data clustering, in particular, to integrate with a hierarchical clustering algorithm. Consequently, this integrated approach can uniformly handle numerical data and categorical data, and also enables one to take the similarity between categorical values into consideration. Experimental results show that the proposed approach produces better clustering results than conventional clustering algorithms when categorical attributes are present and their values have different degree of similarity.     

Measurement uncertainties arising from unpowered shipment of dcvoltage references

We have measured the hysteresis in output voltage arising from loss of power for three Fluke 732B dc voltage references. Continuously powering the internal temperature-controlled oven provides the best accuracy with such Zener-diode-based dc voltage references. Batteries are used to provide power continuity when shipping between laboratories. We have shown that for these particular instruments, an apparent hysteresis induced by humidity is likely to dominate any hysteresis arising from loss of battery power when transit between laboratories takes three days or more. Our conclusion is that as much, if not more, care needs to be taken when dealing with humidity than with loss of battery power when shipping between laboratories. When the highest accuracy of dc voltage comparison is required, it becomes necessary to apply voltage corrections using the measured values of humidity coefficients and the relative humidity occurring during transit     

Activity and characterization of Rh/Al2O3 and Rh-Na/Al2O3 catalysts for the SCR of NO with CO in the presence of SO2 and HCl

SO₂ and HCl are major pollutants emitted from waste incineration processes. Both pollutants are difficult to remove completely and can enter the catalytic reactor. In this work, the effects of SO₂ and HCl on the performance of Rh/Al₂O₃ and Rh-Na/Al₂O₃ catalysts for NO removal were investigated in simulated waste incineration conditions. The characterizations of the catalysts were analyzed by BET, SEM/EDS, XRD, and ESCA. Experimental results indicated the 1%Rh/Al₂O₃ catalyst was significantly deactivated for NO and CO conversions when SO₂ and HCl coexisted in the flue gas. The addition of between 2 and 10 wt.% Na promoted the activity of the 1%Rh/Al₂O₃ catalyst for NO removal, but decreased the CO oxidation and BET surface area. The catalytic activity for NO removal was inhibited by HCl as a result of the formation of RhCl₃. Adding Na to the Rh/Al₂O₃ catalyst decreased the inhibition of SO₂ because of the formation of Na₂SO₄, which was observed in the XRD and ESCA analyses. SEM mapping/EDS showed that more S was residual on the surface of the Rh-Na/Al₂O₃ catalyst than Cl.     

Properties and H2 production ability of Pt photodeposited on the anatase phase transition of nitrogen-doped titanium dioxide

The effect of calcination temperature on the properties and H₂ production ability of nitrogen-doped (N-doped) titanium dioxide (TiO₂) photodeposited with 0.2 wt% Pt (platinum) was studied. The increase in crystallinity of pre-calcinated N-doped TiO₂ initiated at temperatures higher than 131 °C transformed the morphology from anomalous nanostructure to texture composed of nanoparticles and enhanced the specific surface areas. At 200-400 °C, the anatase peaks gradually became sharper and the visible light absorption region decreased due to the growth of crystallites and the decrease of N-doping content, respectively. Maximum H₂ production was reached when N-doped TiO₂ was calcined at 200 °C followed by Pt photodeposition. The maximum condition is brought about by the formation of textures consisting of nanoparticles and a broad absorption region, thus creating superior active sites for photocatalytic H₂ production.