Synthesis and Antifungal Properties of Some Transition Metal Complexes Involving Potentially Active Heterocyclic Ligands

1 : 1 : 1, M(II)-Npa-TCAjHQ mixed-Iigand complexes [M(II)= = Co(II), Ni(II)), Cu(II) and Zn(II); Npa = N-pyridylanthranilic acid; TCA = thiophene-2-carboxylic acid and HQ = 8-hydroxyquinoline] have been prepared and characterized on the basis of elemental analysis, IR and electronic spectral data, conductivity and magnetic measurements. An octahedral environment around the metal ion has been proposed. ALl the complexes are non-electrolytic in nature. The antifungal activity of the free Iigands and their corresponding metal chelates have been determined on some selected fungi

Studies of some lanthanide quaternary complexes

627-629Formation constants of mixed ligand quaternary lanthanide complexes of the type M-A-B-L'/L" where M = La3+, Pr3+, Nd3+; A=ethylenediamine N, N, N', N' -tetraacetic acid (EDTA); B = thiodiglycolic acid (TDA); L' = iminodiacetic acid (IDA) and L" = glycine(Gly) have been determined by pH-metric technique at 35 ± 1°C in 0.1 mol dm-3 KNO3. Stability constants reveal the orders: La(III) < Pr(III) < Nd(III) in terms of metal ions, binary < ternary < quaternary in terms of complex species, and IDA < Gly in terms of amino acids. The log K values are negative for all the ternary and quaternary systems. However, log K values are significantly positive indicating intramolecular hydrophobic ligand-ligand interactions

Synthesis and Antifungal Properties of Some Transition Metal Complexes Involving Potentially Active Heterocyclic Ligands

1 : 1 : 1, M(II)-Npa-TCAjHQ mixed-Iigand complexes [M(II)= = Co(II), Ni(II)), Cu(II) and Zn(II); Npa = N-pyridylanthranilic acid; TCA = thiophene-2-carboxylic acid and HQ = 8-hydroxyquinoline] have been prepared and characterized on the basis of elemental analysis, IR and electronic spectral data, conductivity and magnetic measurements. An octahedral environment around the metal ion has been proposed. ALl the complexes are non-electrolytic in nature. The antifungal activity of the free Iigands and their corresponding metal chelates have been determined on some selected fungi

Gigahertz-Peaked Spectrum Radio Sources in Nearby Galaxies

There is now strong evidence that many low-luminosity AGNs (LLAGNs) contain accreting massive black holes and that the nuclear radio emission is dominated by parsec-scale jets launched by these black holes. Here, we present preliminary results on the 1.4 GHz to 667 GHz spectral shape of a well-defined sample of 16 LLAGNs. The LLAGNs have a falling spectrum at high GHz frequencies. Several also show a low-frequency turnover with a peak in the 1-20 GHz range. The results provide further support for jet dominance of the core radio emission. The LLAGNs show intriguing similarities with gigahertz-peaked spectrum (GPS) sources.Comment: 6 pages, to appear in ASP Conference series, 2002, Vol. 25

Radio Cores in Low-Luminosity AGN: ADAFs or Jets?

We have surveyed two large samples of nearby low-luminosity AGN with the VLA to search for flat-spectrum radio cores, similar to Sgr A* in the Galactic Center. Roughly one third of all galaxies are detected (roughly one half if HII transition objects are excluded from the sample), many of which have compact radio cores. Follow-up observations with the VLBA have confirmed that these cores are non-thermal in origin, with lower limits for the brightness temperatures around ~10^8 K. The brightest of these are resolved into linear structures. The radio spectral indices of the cores are quite flat (alpha~0), with no evidence for the highly inverted radio cores predicted in the ADAF model. Spectrum and morphology of the compact radio emission is typical for radio jets seen also in more luminous AGN. The emission-line luminosity seems to be correlated with the radio core flux. Together with the VLBI observations this suggests that optical and radio emission in at least half the low-luminosity Seyferts and LINERs are black hole powered. We find only a weak correlation between bulge luminosity and radio flux and an apparently different efficiency between elliptical and spiral galaxies for producing radio emission at a given optical luminosity.Comment: 5 pages, 2 figures, (ESO) LaTex, to appear in ``Black Holes in Binaries and Galactic Nuclei'', ESO workshop, eds. L. Kaper, E.P.J. van den Heuvel, P.A. Woudt, Springer Verlag; also available at http://www.mpifr-bonn.mpg.de/staff/hfalcke/publications.html#eso9

Stability constants of some lanthanide mixed ligand complexes

722-725Stability constants of the mixed ligand complexes of some lanthanides, viz., La(III), Pr(III), Nd(III), Gd(III) and Dy(III) with oxydiacetic acid (ODA), tartaric acid (TRA), malic acid (MEA), iminodiacetic acid (IDA) and glycine (GLY) as ligands have been determined pH-metrically at 25 ± 1°C and at an ionic strength of 0.1mol dm-3 (KNO3). A comparison of the values of stability constants of the complexes reveals the order, La(III) K values are negative for all the ternary and quaternary systems; however, DD log K values are significantly positive. These have been explained in terms of intramolecular hydrophobic ligand-ligand interactions. The stability constant data have been used to study the electrostatic factors involved in the formation of these mixed complexes

Effect of dengue virus infection on Fc-receptor functions of mouse macrophages

Fc-receptor-mediated attachment and ingestion of opsonized sheep erythrocytes (EA) by the macrophages of spleen and peritoneal cavity were studied during dengue virus type 2 (DV) infection of Swiss albino mice. Following intracerebral inoculation, virus antigen could be demonstrated by immunofluorescence in the splenic macrophages from day 4 and in peritoneal macrophages from day 5 post-infection, with a higher number of positive cells discernible on the 7th and 8th days. The virus could be isolated from spleen tissue from day 5. The total number of cells was markedly reduced from day 4 onwards both in the spleen and peritoneal cavity. A loss in the capacity to attach and ingest EA was noticed, the lowest values of attachment index (AI) and phagocytic index (PI) being reached on day 4. At later periods the AI values increased markedly but continued to be significantly less than those in uninfected control mice. The PI values continued to be lower throughout. The dichotomy between the Fc-mediated attachment and ingestion may be a mechanism for prevention of virus infection of macrophages

Dengue and dengue haemorrhagic fever: implications of host genetics

Little is known of the role of human leucocyte antigen (HLA) alleles or non-HLA alleles in determining resistance, susceptibility or the severity of acute viral infections. Dengue fever (DF) and dengue haemorrhagic fever (DHF) are suitable models for immunogenetic studies, yet only superficial efforts have been made to study dengue disease to date. DF and DHF can be caused by both primary and secondary infection by any of the four serotypes of the dengue virus. Differences in host susceptibility to infectious disease and disease severity cannot be attributed solely to the virus virulence. Variations in immune response, often associated with polymorphism in the human genome, can now be detected. Data on the influence of human genes in DF and DHF are discussed here in relation to (1) associations between HLA polymorphism and dengue disease susceptibility or resistance, (2) protective alleles influencing progression to severe disease, (3) alleles restricting CD4+ and CD8+ T lymphocytes, and (4) non-HLA genetic factors that may contribute to DHF evolution. Recent discoveries regarding genetic associations in other viral infections may provide clues to understanding the development of end-stage complications in dengue disease. The scanty positive data presented here indicate a need for detailed genetic studies in different ethnic groups in different countries during the acute phase of DF and DHF on a larger number of patients

On the plausible reasons for the formation of onset vortex in the presence of Arabian Sea mini warm pool

It has been established through a numerical model that the onset vortex (OV) was formed dramatically in the shear line on the northern flank of a low level jet (LLJ) at 850 hPa over the mini warm pool (MWP) in the East Central Arabian Sea with the aid of sea surface temperature (SST) anomalies using MONEX-79 data. This study has led to serious investigation of MWP over the ECAS, but little attention has been given to its counterpart, i.e. the atmospheric pattern at 850 hPa, the level at which OV generally forms and extends on either side during the course of development. The present study examines the SST distribution over the Arabian Sea and circulation at 850 hPa to identify the MWP and the LLJ positions for five consecutive days with onset day as its centre and for six consecutive years 2000-05. The study has revealed that OV had formed only in 2001 under the influence of MWP on the northern flank of LLJ. During other years it seldom formed due to (i) absence of MWP, (ii) lack of sufficient strength of LLJ, and (iii) absence of the location of shear line (over the northern flank of LLJ) over MWP. The air-sea flux transfer processes for the OV year 2001 and a non-OV year 2002 are studied and compared for better understanding of the above process in relation to the OV and non-OV weather conditions over the study area