Effect of clay,organic matter and CaCO3 content on zinc adsorption by soils

Summary Zinc adsorption was studied in suspensions of six soils of different physicochemical characteristics in dilute ZnSO₄ solutions. At low concentrations, Zn²⁺ adsorption was described by the Langmuir adsorption equation. The calculated Langmuir adsorption maxima were related positively to clay and carbonate content and negatively with organic matter content of soils. Multiple regression analysis revealed that zinc adsorption maxima can be predicted with good precision from information in soil survey reports. When the added Zn²⁺ exceeded the adsorption maximum, the solid phase of zinc controlling its concentration in solution was either zinc hydroxide or carbonate so long as soil carbonates were present. The values of zinc potential also indicated that soils retain Zn²⁺ more strongly than Zn(OH)₂ or carbonate. Postgraduate student Professor of Soils. Professor of Soils.     

Spontaneous demonstration of counterclockwise right atrial activation following successful isthmus ablation

We describe an uncommon case of typical flutter with symptomatic sinus node dysfunction, in which a permanent junctional rhythm developed following ablation of the cavo-tricuspid isthmus. This rhythm activated the right atrium in counter clockwise manner thus providing spontaneous proof of unidirectional isthmus block, a phenomenon that is usually demonstrated by proximal coronary sinus pacing.     

U wave: an important noninvasive electrocardiographic diagnostic marker

Study of U waves exemplifies important clinical role of noninvasive electrocardiography in modern cardiology. Present article highlights significance of U waves with a clinical case and also summarizes in brief the history of the same.     

Effect of extracellular products ofAulosira fertilissima on the growth of rice seedlings

Summary The effect of extracellular products fromAulosira fertilissima on the growth of rice seedlings (IR-8) has been studied. There is indication of liberation of a root-promoting hormone from the alga. The growth pattern of rice seedlings, treated with algal filtrate, parallels that of seedlings treated with gibberellic acid. An increased growth of rice seedlings results when they are treated with algal filtrate obtained from the exponential phase of the alga. The amino acid-treated seedlings do not show any marked increase in growth. Filtrate fromAnacystis nidulans, on the other hand, do not show any growth promoting response. The possibility of liberation of kinins byA. fertilissima does not appear to be involved.     

Synthesis of novel tricyclic oxazolidinones by a tandem SN2 and SNAr reaction: SAR studies on conformationally constrained analogues of Linezolid

A series of conformationally constrained analogues of Linezolid were synthesised by employing a tandem SN(2) and SNAr reaction as the key step and tested for antibacterial activity. While the hexahydroazolo-quinoxaline compounds were inactive, the tetrahydroazolo-benzothiazine compounds exhibited interesting antibacterial activity. The introduction of fluorine in the aromatic ring further made the compounds more potent in acetamide compounds resulting in an interesting analogue 32. However, the introduction of fluorine (analogue 34) on the already potent non-fluorine thiocarbamate 21 did not have any influence on the activity.     

Synthesis and antibacterial activity of novel oxazolidinones bearing N-hydroxyacetamidine substituent

Novel oxazolidinone antibacterials containing N-hydroxyacetamidine moiety are synthesized with the diversity at C-5 terminus. These compounds have been evaluated against a panel of clinically relevant gram-positive and gram-negative pathogens. Most of the analogs in this series displayed activity superior to Linezolid and in vivo efficacies of selected oxazolidinones are also disclosed herein.