On the fields in a conical horn having an arbitrary wall impedance

The electromagnetic fields propagating up a cone having an arbitrary wall impedance are found using an asymptotic solution. Three special cases are then considered: the smooth-metal wall, the corrugated wall, and the metal wall with a lossy-dielectric lining. The last case, in the form of an absorber-lining is then shown to behave like a corrugated horn since it too provides a highly taperedE-plane andH-plane aperture distribution. Furthermore, it does this over a much larger bandwidth, over 3:1, with negligible gain drop.     

Important parameters for the manufacture of slow-release matrix pellets with an aqueous dispersion of quaternary poly(meth)acrylates in the rotary fluidized bed

The manufacture of slow-release matrix pellets with an aqueous dispersion of quaternary poly(meth)acrylates was investigated in the rotary fluidized bed. By considering the moisture content of the fluidized bed to be the key process parameter, it was measured on-line throughout the whole manufacturing process. A specially designed sampling device opened new ways to apply NIR spectrometry in laboratory scale processes. It was shown that reproducibly improved pellet properties can be achieved by reproducing the moisture content of the (rotary) fluidized bed. Moisture plateaus proved to be a suitable way to optimize the sphericity of the pellets. Premoisturizing was found to be a very effective tool to achieve slow-release dissolution of the model drug theophylline.     

Treated Oil Shale Ashes as a Substitute for Natural Aggregates,Sand, and Cement in Concrete

Oil shales are rocks that contain organic matter and are used as a low-grade fuel for energy production. The oil shale combustion process produces large quantities of ash as combustion wastes. These residues contain a high concentration of calcium anhydrite (CaSO₄) and calcium carbonate (CaCO₃), which can be utilized to neutralize acidic wastes (e. g., wastes from the phosphate industry) .Using untreated oil shale bottom ash as partial substitutes for aggregates, natural sand, and cement in concrete mixtures has resulted in a significantly decreased performance of the concrete mixtures. However, by blending the oil shale with acidic materials, the concrete properties improved, as manifested by the development of compressive strength and the workability of the concrete mixtures. In the current study, it was shown that treatment of the oil shale ash with the acidic waste of the Israeli phosphate industry or with phosphoric acid significantly improves the properties of the concrete mixtures, by partial replacement of the natural aggregates and sand by the treated oil shale ash.     

Induction of tolerance by IL-10-treated dendritic cells

Dendritic cells (DC) form a specialized system for presenting Ag to naive or quiescent T cells and consequently play a central role in the induction of T and B cell immunity. In this study we used DC generated from peripheral progenitors to analyze the effect of IL-10 on the accessory function of human DC. We demonstrate that immature DC, harvested on days 9 to 11 and exposed to IL-10 for the last 2 days of culture, show a strongly reduced capacity to stimulate a CD4+ T cell response in an allogeneic MLR in a dose-dependent manner. In contrast, fully mature DC are completely resistant to the effects of IL-10. These results were obtained in both an alloantigen-induced MLR and an anti-CD3 mAb-induced response of primed and naive (CD45RA+) CD4+ T cells. FACS analysis revealed inhibition of the up-regulation of the costimulatory molecules CD58 and CD86 and the specific DC marker CD83 in DC pretreated with IL-10. These data suggest that IL-10 inhibited the development of fully mature DC. Furthermore, DC precultured with IL-10, but not controls, induced a state of alloantigen-specific anergy in CD4+ T cells and of peptide-specific anergy in the influenza hemagglutinin-specific T cell clone HA1.7. Analysis of the supernatants of these anergic T cells revealed a reduced production of IL-2 and IFN-gamma compared with that in control cells. Collectively, these data suggest that IL-10 converts immature DC into tolerogenic APC, which might be a useful tool in the therapy of patients with autoimmune or allergic diseases.     

Direct evidence that FK506 inhibition of FcepsilonRI-mediated exocytosis from RBL mast cells involves calcineurin

The development of human endocrine pancreas has been the subject of many immunohistochemical studies but very little is known at the molecular level. We have determined the patterns of gene expression of glucagon, somatostatin and pancreatic polypeptide during fetal life (16-41 weeks of gestation) using the dot-blot hybridization method. In spite of some dispersion in the mRNA levels, no progressive increase or decrease during this period of fetal life could be found, as previously observed for insulin. In keeping with these molecular data, no increase in immunostaining of the four hormones was observed, but a dispersion of endocrine cells within the exocrine tissue was noticed at 20 weeks of gestation followed by a clear differentiation of the Langerhans islets at 31 weeks. Interestingly, the mRNA levels of the four hormones were always higher in the fetal pancreas than in the adult pancreas.