Opportunistic Spectrum Sharing using Dumb Basis Patterns: The Line-of-Sight Interference Scenario

We investigate a spectrum-sharing system with non-severely faded mutual interference links, where both the secondary-to-primary and primary-to-secondary channels have a Line-of-Sight (LoS) component. Based on a Rician model for the LoS channels, we show, analytically and numerically, that LoS interference hinders the achievable secondary user capacity. This is caused by the poor dynamic range of the interference channels fluctuations when a dominant LoS component exists. In order to improve the capacity of such system, we propose the usage of an Electronically Steerable Parasitic Array Radiator (ESPAR) antenna at the secondary terminals. An ESPAR antenna requires a single RF chain and has a reconfigurable radiation pattern that is controlled by assigning arbitrary weights to M orthonormal basis radiation patterns. By viewing these orthonormal patterns as multiple virtual dumb antennas, we randomly vary their weights over time creating artificial channel fluctuations that can perfectly eliminate the undesired impact of LoS interference. Because the proposed scheme uses a single RF chain, it is well suited for compact and low cost mobile terminals

SYNTHESIS, Spectroscopic Characterization and Evaluation (Antibacterial & (GOT, G pT) Enzyme )Activity of Mixed Ligand Complexes of M(II) with Amino Acid (L-Asparagine) and Schiff Bases Derived from (Sulfamethoxazo Drug with 2,4Dimethoxybenzaldehyde)

Mixed ligand  Mn(II),Co(II), Ni(II),Cu(II) , Zn(II), Cd(II) and  Hg(II)complexes with a bidendate  Schiff base prepared by condensation of (Sulfamethoxazo  Drug  With 2,4Dimethoxybenzaldehyde) as a primary ligand and  potassium asparaginate as secondary ligand  were synthesized and characterized on the basis of   molar conductance measurements, magnetic susceptibility values, UV-Vi s ,FT- IR, spectral data wherever possible. Electronic spectra and magnetic susceptibility measurement reveal octahedral geometry for   all M(II) complexes. The complexes are found to be non-electrolytic in nature on the basis of low molar conductance. The antibacterial activity of the free ligands HL and there metal complexes were tested against the bacterial ( E.coli, Staphylococcus aureus, Psedomonas and Acinetobactera) Keywords:: biidendate, Schiff base, Antibacterial

Preparation, Characterization, and Antibacterial Properties of mixed ligand Complexes of L-leucine and Sulfamethoxazole with Mn(II),Co(II),Ni(II),Cu(II),Zn(II),Cd(II)and Hg(II) ions

The research includes the synthesis and identification of the mixed ligands complexes of M+2 Ions  in general composition  ,[M(Leu)2(SMX)] Where L-leucine(C6H13NO2)symbolized (LeuH) as a primary ligand and Sulfamethoxazole (C10H11N3O3S)symbolized (SMX)) as  a secondary  ligand . The ligands and the metal chlorides were brought in to reaction at room temperature in(v/v) ethanol /water as solvent containing NaOH. The reaction required the following [(metal: 2(Na+ Leu-): (SMX)] molar ratios with M(II) ions, Were  M(II) = Mn(II),Co(II),Ni(II),Cu(II),Zn(II),Cd(II)and Hg(II). The UV–Vis and magnetic moment data revealed an octahedral geometry around M(II), The conductivity data show a non-electrolytic nature of the complexes. The antimicrobial activities of ligands and their mixed ligand complexes were screened by disc diffusion method. Keywords: Sulfamethoxazole(antibiotic), L-leucine, Mixed ligand, Metal complexes, Antimicrobial activity