On pre-Λ-Sets and pre-v-Sets

We introduce the notions of a pre--set and a pre-V-set in a topological space. We study the fundamental properties of pre--sets and pre-V-sets and investigate the topologies defined by these families of sets.     

Some properties of almostS-continuous functions

Noiri et al. in [16] introduced and investigated the notion of almosts-continuous functions. The object of this paper is to investigate some more properties of this type of functions.     

Hardness and refractive index of Ca–Si–O–N glasses

Vickers hardness and refractive index was determined for Ca–Si–O–N glasses with 14.6–58 e/o N and 19–42 e/o Ca. By applying slow cooling rates, transparent glasses were obtained for compositions near Ca_9.94Si₁₀O_17.73N_8.14, while the majority of the glasses were opaque due to small inclusions of elemental Si and/or Ca-silicide. Determined glass densities varied between 2.80 and 3.25 g/cm³. Hardness was found to vary from 7.3 to 10.1 GPa at a load of 500 g and, respectively increase and decrease linearly with N and Ca content. The refractive index was found to increase linearly with N content from 1.62 to 1.95 and showed no significant dependence on Ca content.     

One-pot synthesis of pyrano[2,3-d]pyrimidinone derivatives catalyzed by L-proline in aqueous media

An efficient protocol has been developed for the synthesis of various pyrano[2,3-d]pyrimidinones from condensation of aromatic aldehydes, malononitrile and barbituric-or thiobarbituric acid in aqueous ethanol using L-proline as a neutral bifunctional catalyst.     

New Zn(II) complexes based on biologically active substituted acetic acid and nitrogen donor ligands: synthesis,crystal structure and biological applications

The complexes [Zn(phenylacetato)₂(2-aminopyridin)₂] (3), [Zn(phenylacetato)₂(1,10-phenanthroline)]·H₂O (4), and [Zn(phenylacetato)₂(2,9-dimethyl-1,10-phenanthroline)]·0.5 H₂O (5) were prepared and characterized by IR-, UV–Visible, ¹H and ¹³C NMR spectroscopy, and single crystal X-ray diffraction. BNPP hydrolysis of the complexes and their parent nitrogen ligands showed that the hydrolysis rate of bis-(4-nitrophenyl) phosphate (BNPP) was 1.7 × 10⁵ L mol^?1 s^?1 for 3, 3.1 × 10⁵ L mol^?1 s^?1 for 4 and 4.3 × 10⁴ L mol^?1 s^?1 for 5. Antibacterial activities show the effect of complexation on activity against Gram-positive (S. epidermidis, S. aureus, E. faecalis, M. luteus and B. subtilis) and Gram-negative (K. pneumonia, E. coli, P. mirabilis and P. aeruginosa) bacteria using the agar well diffusion method. Complex 4 showed good activity against G? bacteria except P. aeruginosa, and against G+ bacteria except E. ferabis. Complex 5 showed no activity against G? bacteria, low activity against M. luteus and B. subtilis bacteria and high activity against S. epidemidis and S. aureus. Complex 3 did not show any activity against G? or G+ bacteria.     

Tetrathiafulvalene based electroactive ligands and complexes: Synthesis,crystal structures and antifungal activity

The synthesis of two tetrathiafulvalene-appended pyridinehydrazone pyrimidine ligands, namely (Z)-4-(2-((5-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L1 and (Z)-4-(2-((6-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L2 is described. Ligand L1 was reacted with cobalt(II) to yield a cationic metal complex [Co(L1)₂] while ligand L2 was reacted with zinc(II) to afford a neutral metal complex [ZnL2Cl₂]. The crystal structure analysis of [Co(L1)₂] indicate that Co(II) ion is coordinated by six nitrogen atoms from two perpendicular ligands while in [ZnL2Cl₂], Zn(II) is coordinated by two chlorine atoms and three nitrogen atoms. The electrochemical behavior indicate that ligands L1 and L2 and the zinc(II) complex are suitable fort the preparation of crystalline radical cation salts. Finally the determination of MIC₈₀ values against C. albicans, C. glabrata, C. parapsilosis, C. krusei and E. dermatitidis revealed that the cobalt(II) metal complex [Co(L1)₂] is active against all the studied fungi.