Reactions of piroxicam with alkyl iodides

Alkylation of piroxicam with a homologous series of alkyl iodides gave reversibly formed O-alkyl products 1 as well as unexpected, irreversibly formed zwitterionic compounds 2 , alkylated on the pyridine nitrogen, and O,N-bis-alkyl products 3 . Proof of structure was accomplished by nmr and X-ray crystal analysis. Product distribution ratios were determined by hplc and are explained by the Hard-Soft Acid-Base principle.     

Singularities of the solution of a mixed problem for a general second order elliptic equation and boundary stabilizationof the wave equation

We deal here with a second order elliptic mixed problem which is posed in a regular open bounded domain of . We study the regularity of its solution. We apply our results to the boundary stabilization of the wave equation.     

Characterization of Sub‐Micron Perovskite Suspensions Formed Through Cavitation Processing

The size distribution within and electrokinetic properties of aqueous perovskite (LaCoO₃) suspensions, have been characterized as a function of processing conditions. Submicron–sized perovskite particles have been obtained using a cavitation technique in which the suspension is passed through a series of small orifices under extreme driving pressure drops. When no additives were used, the zeta potential of the particles was found to be positive over the entire pH range studied. Use of an acrylic copolymer surfactant with multiple negatively charged sites during the cavitation processing was found to improve dispersion stability. The observed variations in zeta potential and particle size for the suspensions are explained in terms of electrostatic interactions between particles, the tendency for the surfactant to adsorb onto the particles, and the degree of steric stabilization provided by the surfactant.     

Determination of bromine, chlorine and iodine in environmental aqueous samples by epithermal neutron activation analysis and Compton suppression

Summary Halides, particularly Br^- and Cl^-, have been used as indicators of potential sources of Na⁺ and Cl^- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na⁺ and Cl^- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using epithermal NAA in conjunction with Compton suppression.     

Photoionization of highly charged ions using an ECR ion source and undulator radiation

Photoionization of Xe4+ to Xe7+ ions was studied by combining an electron cyclotron resonance ion source with synchrotron radiation. Multiconfiguration Dirac-Fock calculations were performed to interpret the data. Many autoionization lines were measured and identified, resulting from excitation of a 4d electron into nf and np orbitals followed by Auger decay of the excited states. Continuum photoionization is negligible for the higher members of the isonuclear series.     

Discovery of a potent small molecule IL-2 inhibitor through fragment assembly

Using a site-directed fragment discovery method called tethering, we have identified a 60 nM small molecule antagonist of a cytokine/receptor interaction (IL-2/IL2Ralpha) with cell-based activity. Starting with a low micromolar hit, we employed a combination of tethering, structural biology, and computational analysis to design a focused set of 20 compounds. Eight of these compounds were at least 5-fold more active than the original hit. One of these compounds showed a 50-fold enhancement and represents the highest affinity inhibitor reported against this protein-protein target class. This method of coupling selected fragments with a low micromolar hit shows great potential for generating high-affinity lead compounds.