Some new 3-substituted-4-amino-5-mercapto-4(H)-1,2,4-triazoles as nonsteroidal antiinflammatory agents

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Somaclonal variations for crop improvement: Selection for disease resistant variants in vitro

Somaclonal variations (SV) are genetic or epigenetic changes induced in plant cell and tissue culture. Induction of somaclonal variation, is an alternate approach to conventional breeding and transgenic approaches to introduce desirable genetic variability in the gene pool. SVs that occur spontaneously in culture induce changes in a range of plant characters. However, the probability of improving a key agronomic trait such as disease resistance can be cumbersome when left to chance alone. The efficiency of developing disease resistant SVs is better with the imposition of an appropriate in vitro selection pressure. Selection agents that have been applied include pathogen elicitors, pathogen culture filtrate and purified pathotoxins. This method of SV selection has been successful in enhancing disease resistance in several crops and it is an accepted biotechnological approach with tremendous potential for crop improvement

Action planning and the timescale of evidence accumulation

Perceptual decisions are based on the temporal integration of sensory evidence for different states of the outside world. The timescale of this integration process varies widely across behavioral contexts and individuals, and it is diagnostic for the underlying neural mechanisms. In many situations, the decision-maker knows the required mapping between perceptual evidence and motor response (henceforth termed “sensory-motor contingency”) before decision formation. Here, the integrated evidence can be directly translated into a motor plan and, indeed, neural signatures of the integration process are evident as build-up activity in premotor brain regions. In other situations, however, the sensory-motor contingencies are unknown at the time of decision formation. We used behavioral psychophysics and computational modeling to test if knowledge about sensory-motor contingencies affects the timescale of perceptual evidence integration. We asked human observers to perform the same motion discrimination task, with or without trial-to-trial variations of the mapping between perceptual choice and motor response. When the mapping varied, it was either instructed before or after the stimulus presentation. We quantified the timescale of evidence integration under these different sensory-motor mapping conditions by means of two approaches. First, we analyzed subjects’ discrimination threshold as a function of stimulus duration. Second, we fitted a dynamical decision-making model to subjects’ choice behavior. The results from both approaches indicated that observers (i) integrated motion information for several hundred ms, (ii) used a shorter than optimal integration timescale, and (iii) used the same integration timescale under all sensory-motor mappings. We conclude that the mechanisms limiting the timescale of perceptual decisions are largely independent from long-term learning (under fixed mapping) or rapid acquisition (under variable mapping) of sensory-motor contingencies. This conclusion has implications for neurophysiological and neuroimaging studies of perceptual decision-making

Synthesis, antimicrobial and antituberculosis activities of <i>N</i>-bridged heterocycles

828-833The reactions of 3-[(((α-phenyl/methyl)benzylidene)amino)oxy]methyl/ethyl-4-amino-5-mercapto-4(H)-1,2,4-triazoles 1a-d, with various aliphatic/aromatic acids 2a-d-5a-d, oxalic acid 6a-d, cyanogen bromide 7a-d, carbon disulphide 8a-d, hydrazine hydrate (99%) 9a-d, monochloroacetic acid 10a-d, phenacyl bromide 11a-d, benzoin 12a-d, dimidone 13a-d and chalcone 14a-d are described. The characterisation of the compounds have been done on the basis of elemental analysis and spectral (IR, 1H NMR and mass) data. All the newly synthesised compounds have been screened for antimicrobial activity against B. cirroflagellosus, E. coli, A. niger and R. bataticola. Most of the compounds have also been screened for antituberculosis activity against M. tuberculosis, H37Rv strain. Results of antimicrobial screening revealed that majority of the newly synthesised N-bridged heterocycles exhibit better antimicrobial activity than the standards cotrimoxazole and fluconazole. A few of the compounds exhibit significant antituberculosis activity in comparison with rifampin, the standard used