Efficacy of organophosphorus derivatives containing chalcones/chalcone semicarbazones against fungal pathogens of sugarcane

Ten newly synthesized organophosphorus derivatives containing substituted chalcones and substituted chalcone semicarbazones were tested for their antifungal efficacy against Colletotrichum falcatum, Fusarium oxysporum, Curvularia pallescens (all sugarcane pathogens). The O,O-diethylphosphate derivatives containing 2-chlorochalcone and 2-chlorochalcone semicarbazone exhibited 70-85% mycelial inhibition against all the test fungi at 1000 ppm. The screening results were correlated with structural features of the tested compounds.     

Spatial-frequency-tuned mechanisms of the red-green channel estimated by oblique masking

The sustained spatial-frequency-tuned (SF-tuned) mechanisms of nonoriented units were examined by means of orthogonal masking for the Red-Green (R-G) color channel, and those of oriented units by oblique masking for the achromatic channel but not for the color channels. An oblique-masking technique minimizes the artifacts that are due to spatial phase effects, local cues, spatial beats, spatial probability summation, and changing criteria. Therefore the spatial characteristics of the R-G color channel are now investigated by an oblique-masking technique and linked with my paper on orthogonal masking [J. Opt. Soc. Am. A 15, 1 (1998)]. The R-G channel was defined by the minimum-flicker and hue-cancellation techniques. A color monitor system was used to generate spatially localized (D6) vertical color test patterns [0.063-8 cycles per degree (cpd)] and sinusoidal oblique color masks (0.031-16 cpd, 1.2-60% contrasts). Color contrast sensitivity functions (CSFs), threshold elevation (TE) versus mask SF (TvSF) curves, and TE versus mask contrast (TvC) curves were measured by the method of constant stimuli with a two-interval forced-choice technique by using Powell's achromatizing lens under sustained (Gaussian, 2-s-duration) conditions. Results show the following: (1) The color CSF is a low-pass function of SF with average half-height SF of 0.7 cpd and cutoff SF of 14 cpd with the use of a color-detection criterion. (2) TvSF curves are broadly bandpass and fall into five groups, peaking at approximately 0.13, 0.5, 2, 4, and 8 cpd. The root-mean-square cone-color CSF is 3.8-5.4 times the stimulus-color CSF. (3) A "crowding effect" similar to that of the TvSF curves of the achromatic channel was also found, but the TvSF curves of the R-G channel are not sharply peaked, similar to the result for orthogonal masking. Data analysis led to the following conclusions: (1) A simple multiple-mechanism model yields one low-pass color mechanism (with average half-height SF of 0.54 cpd) and five bandpass SF-tuned color mechanisms; these six mechanisms are necessary to explain the CSF, TvSF, and TvC data simultaneously. (2) The bandpass mechanisms peaked at approximately 0.13, 0.5, 2, 4, and 8 cpd with average full bandwidths at half-heights of 3.6, 3.2, 2.1, 1.2, and 1.3 octaves, respectively. (3) Since oblique-masking color mechanisms (unlike achromatic oriented mechanisms) have broad orientation tuning under sustained conditions and there is a significant orthogonal masking, the oblique-masking color mechanisms may have contributions from both oriented and nonoriented units. (4) The high degree of similarity between the SF-tuned filters of mechanisms derived from oblique- and orthogonal-masking data suggests that most of the chromatic SF tuning is already accomplished by nonoriented units. (5) The quality of the fit to oblique- and orthogonal-masking data combined dropped enough to reject the hypothesis that the former taps the performance of only the same nonoriented mechanisms as those by the latter. Adding gain parameters that reduce the TEs for orthogonal masking gave a better fit, suggesting that orientation gains are one of the factors involved in the transformation of information from nonoriented to oriented mechanisms. However, the fit was still worse than that for oblique-(6) Since masking-alone or orthogonal-masking-alone data, suggesting that more factors may be involved. primate parvo lateral geniculate nucleus (pLGN) units behave in a fairly linear manner, the color contrast nonlinearity (which follows the linear filter) of a mechanism may be post-pLGN.     

Damage-Coupled Progressive Failure and Yield Line Analyses of Metal Plates

Continuum damage mechanics based progressive failure analysis of an aluminum alloy AL2024-T3 plate has been carried out. Isotropic continuum damage mechanics model proposed by Chandrakanth and Pandey in 1995 has been implemented in a nonlinear finite element computational scheme based on damage-coupled and damage-uncoupled elastoplastic constitutive relationship. In order to model the progressive growth of damage and plasticity from extreme fibers toward the neutral axis, discrete layered approach has been adopted in the formulation using Ahmed’s degenerate isoparametric shell element, which accounts for shear deformation. A critical damage criteria is used for determining the onset and propagation of failure in the plate. Damage-coupled and damage-uncoupled analyses have been carried out on rectangular and triangular plates of aluminum alloy Al2024-T3. Yield line patterns have been generated using extensive nonlinear progressive failure analysis and comparison with conventional yield line analysis has been made. It is envisioned that employing the methodology presented herein, yield line pattern generation for structural components with complex shapes can be obtained, which would significantly assist engineers in analysis and design of structures.     

Inhibition of salvinia (Salvinia molesta Mitchell) by parthenium (Parthenium hysterophorus L.). I. Effect of leaf residue and allelochemicals

Parthenium (Parthenium hysterophorus L.) leaf residue (LP, leaf powder) inhibited salvinia (Salvinia molesta Mitchell) biomass and the number of healthy fronds at 0.25% (w/v) and killed the treated plants at and above 0.75% (w/v) in about 5–15 days, depending on the quantity of the residue. At the lethal dose, the LP caused an abrupt desiccation of above-water plant parts, probably due mainly to root dysfunction. This was concurrent with the loss of dehydrogenase activity in, and an increase in solute leakage from, the roots and loss of chlorophylla, b, and total chlorophyll contents in the fronds, resulting in death of the treated plants. The LP appears inhibitory to salvinia through affecting macromolecules—proteins, lipids, and nucleic acids. The inhibitory activity of LP at the lethal dose suspended in water was completely lost when allowed to stand for 30 days under outdoor conditions and promoted growth of the salvinia plants placed in it. The standard allelochemicals, including those present in parthenium LP, except parthenin andp-hydroxybenzoic acid, did not inhibit growth up to 100 ppm. However, parthenin andp-hydroxybenzoic acid killed salvinia plants at 100 and 50 ppm, respectively. Sincep-hydroxybenzoic acid is unlikely to be present at such a high concentration, parthenin appears to be one of the main allelochemicals responsible for the inhibitory effect of parthenium leaf residue on salvinia.A portion of this work was presented at the International Symposium on Weed Management for Sustainable Agriculture held at C.C.S. Haryana Agricultural University, Hissar, India, November 18–20, 1993.     

Diffusion of Impurity Excitations in Superfluid and Solid 3He–4He Mixtures

Starting from the system of linearized kinetic equations, the exact expressions for the spin and mass diffusion coefficients and thermal diffusion ratio in quantum mixtures of helium isotopes with any degree of degeneration is obtained. From the general expression the various limiting expressions have been obtained, which are determined by various relations between collision rates of quasiparticles. The results of the calculations are compared with available experimental data. It is shown that in the low-temperature region, where an impuriton gas is one-component, the relaxation of concentration of ³ He in superfluid ³ He– ⁴ He mixtures is determined by the acoustic and dissipative collective modes with an effective diffusion coefficient. From the general relation, the expression for a spin diffusion coefficient in solid ³ He– ⁴ He quantum mixtures is derived. The comparison of the results obtained with the experimental data makes it possible to find a numerical value for the width of the impuriton energy zone.     

Altered sensorium in neurological infections and the homeostasis of Mg,Zn, Cu and Ca

In a grave illness the homeostasis of some elements may be upset either by the disease process per se, or by the therapy adopted. Patients with pyogenic, viral and tubercular meningo-encephalitis were targets of interest. 108 subjects' serum and cerebrospinal fluid (CSF) compartments were assayed for magnesium, calcium, zinc and copper, by atomic absorption spectrometry. Results showed that the serum pool was more intensely altered than the CSF pool in the case of magnesium and calcium but the reverse occurred for zinc and copper. No organism-dependent change was noted, but comatosed patients were the worst effected. These findings are discussed with respect to the relative brain and CSF content of each element and the patho-physiology which could alter the compartments studied.     

Chip-based analysis of protein-protein interactions by fluorescence detection and on-chip immunoprecipitation combined with microLC-MS/MS analysis

A new chip-based method to identify protein-protein interactions was developed using the guanine nucleotide exchange factor GRF2 and two interacting proteins, Ras and calmodulin, as model proteins. A generic immobilization strategy for FLAG-tagged bait proteins on a protein-repellent streptavidin chip surface was implemented by presentation of an oriented anti-FLAG antibody. A flow cell device, integrating different chip surfaces, was developed, and the interaction of immobilized GRF2 with the two analytes was verified by fluorescence assays. On-chip tryptic digest assays were then performed on the capture surface and analyzed by microLC-MS/MS. The interaction of GRF2 with calmodulin and Ras was demonstrated, and the lower limit of detection was determined. We also implemented an on-chip immunoprecipitation assay to identify GRF2-binding partners from complex protein mixtures. Cells overexpressing FLAG-GRF2 were lysed and then incubated with the anti-FLAG chip. In addition to detecting GRF2, we also identified calmodulin, demonstrating that this technique can successfully identify endogenous levels of proteins, bound to recombinant bait proteins. This chip-based method has the advantage that no subsequent gel separations of protein complexes prior to LC-MS analysis are required and is therefore amenable to miniaturized high-throughput determination of protein-protein interactions.     

Development and in vitro evaluation of diltiazem hydrochloride transdermal patches based on povidone-ethylcellulose matrices

To select a suitable formulation for the development of transdermal drug-delivery system of diltiazem hydrochloride. Transdermal patches of the drug, employing different ratios of polymers, ethylcellulose (EC), and povidone (PVP) were developed and evaluated for the potential drug delivery using depilated freshly excised abdominal mouse skin. The influence of different film compositions on in vitro drug permeation into receptor fluid were studied using a modified Franz diffusion cell. The cumulative amount of drug was found to be proportional to the square root of time, i.e., Higuchi kinetics. From this study, it was concluded that the films composed of povidone:ethylcellulose (1:2) should be selected for the development of transdermal drug-delivery system of diltiazem hydrochloride, using a suitable adhesive layer and backing membrane, for potential therapeutic use.