Selective catalytic reduction by urea in a fluidized‐bed reactor

The selective catalytic reduction (SCR) of NO_x by urea as a reducing agent was carried out over fresh and sulfated CuO/γ‐Al₂O₃ catalysts in a fluidized‐bed reactor. The optimum temperature ranges for NO reduction on the fresh and sulfated CuO/γ‐Al₂O₃ catalysts were 300–350 °C and 400–450 °C, respectively. NO reduction with the sulfated CuO/γ‐Al₂O₃ catalyst was somewhat higher than that with the fresh CuO/γ‐Al₂O₃ catalyst. N₂O formation increased with increasing reaction temperature. Ammonia (NH₃) slip increased with increasing gas velocity and decreased with increasing reaction temperature. Copyright © 2003 Society of Chemical Industry     

Dopamine transporter development in postnatal rat striatum: an autoradiographic study with [3H]WIN 35,428

The dopamine transporter mediates the reinforcing effects of cocaine, thus playing a central role in human cocaine addiction, and perhaps providing the mechanism for inducing the effects of prenatal cocaine exposure. This possibility has stimulated growing interest in the normal and abnormal development of this transporter. [3H]WIN 35,428 is a cocaine analog that is useful for studying the distribution and density of the dopamine transporter in striatum and other brain regions. The postnatal development of the dopamine transporter in the rat striatum was measured by quantitative autoradiography with [3H]WIN 35,428. Dopamine transporter levels were low at birth, increased through day 15, followed by much more rapid growth in late postnatal development. The majority of the transporter sites appeared after day 15. Lateral to medial and anterior to posterior gradients in transporter density were established early during development, and there was also an early concentration of transporter in striosomes that became difficult to identify by day 15. Differences between the developmental patterns described here and studies using other ligands for the dopamine transporter suggest there are significant differences in the transporter binding sites for these drugs. These differences in transporter ligand binding characteristics may reflect developmental changes in post-translational modification of the transporter and/or changes in the functional activity rather than simply the presence of the transporter.     

Indirect mitogenic effect of transforming growth factor-beta on cell proliferation of subconjunctival fibroblasts

Single amino acid replacement analogs of Manduca adipokinetic hormone (M-AKH) pGlu-Leu-Thr-Phe-Thr-Ser-Ser-Trp-GlyNH2 were tested for activity in bioassays as well as receptor binding assays. Amino acids were replaced by Ala and by D-analogs. In addition an extended M-AKH and analogs containing photo affinity labels were tested. All analogs had reduced activity. All the peptides which had enough activity to allow a full dose response curve reached the same maximal activity as native M-AKH. The use of analogs, in which L-Phe4 was replaced by Ala or by D-Phe and of L-Thr3 replaced by D-Thr, as competitors led to improved binding of M-AKH in our competitive receptor binding assay. In the bioassay an inactive concentration of Ala4 M-AKH increased the activity of a half optimal concentration of native M-AKH.