Treatment of Pea Seeds with Plasma Activated Water to Enhance Germination,Plant Growth,and Plant Composition

Plasma Chemistry and Plasma Processing - The present study has been carried to investigate the interaction and effect of plasma activated water (PAW) on pea seeds. PAW is produced with the...     

Some inhomogeneous magnetized viscous-fluid cosmological models with varyingΛ

Some cylindrically symmetric inhomogeneous viscous-fluid cosmological models with electromagnetic field are obtained. To get a solution a supplementary condition between metric potentials is used. The viscosity coefficient of bulk viscous fluid is assumed to be a power function of mass density. Without assuming anyad hoc law, we obtain a cosmological constant as a decreasing function of time. The behaviour of the electromagnetic field tensor together with some physical aspects of the model are also discussed.     

A Connecting Link between Lorentz and Dirac Theories of Electrons

A theory, that is an initial step towards bridging the gap between Lorentz and Dirac theories of electrons, is presented. An electromagnetic Lagrangian density is postulated, such that, the theory can be cast into a form, similar to Dirac theory. Electromagnetic interpretation of conserved currents, and of usual bilinear covariants in the Dirac theory, is obtained. A counterpart of Abraham-Lorentz equation, with oscillatory solutions is derived. Self-energy of electrons is expressed in terms of their self-potentials and self-currents.     

On the non-BoltzmannA-X emission in Na2 following laser excitation of theB state

A ¹Σ _u ⁺ -X ¹Σ _g ⁺ emission in Na₂ is observed following excitation ofB ¹π _u by various lines of an argon ion laser. The excitation energy ofB ¹π _u is collisionally transferred to the (2)¹Σ _g ⁺ which then radiatively populates theA ¹Σ _u ⁺ state. The Na vapour is contained in a stainless steel crossed heat pipe with Ar buffer gas and temperature around 600°C. For all laser lines except 4579 Å, the coarse features ofA-X emission are independent of the laser wavelength. However, at high resolution the finer differences between different laser line excitation are explained. Variousv′-v″ transitions in this emission are identified. Computer simulation is presented to help explain some features of this emission.     

Growth and reactivity of silver clusters in amino polycarboxylic acid solutions

Reduction and subsequent aggregation of silver ions in the presence of various chelating agents such as trans-1,2-diaminocyclohexanetetraacetic acid (DCTA) 1,2-propylenediaminetetraacetic acid (PDTA), diethylenetriaminepentaacetic acid (DTPA), and triethylenetetraaminehexaacetic acid (TTHA) have been studied by pulse radiolysis. Rate constants of formation and transient absorption spectra for the ligand-complexed Ag(0) and Ag(2)(+) have been determined. The redox potential of Ag(+)(L)/Ag(0)(L) becomes more negative than that of Ag(+)/Ag(0). Growth and reactivity of silver clusters were also studied in the presence of methyl viologen (MV(2+)). The kinetics of formation of the MV(+*) radical, produced by the same pulse as in the case of silver atoms, confirms the catalytic electron transfer toward super critical silver clusters in the presence of ligands. The results suggest that catalytic electron transfer activity of silver clusters depends on the ligand.     

Kinetics and mechanism of polymerization yielding stereoblock poly(methyl methacrylate) with VCl4-Al(C2H5)3 catalyst system

Methyl methacrylate was polymerized at 40°C with the VCl₄–AlEt₃ catalyst system in n-hexane. The rate of polymerization was proportional to the catalyst and monomer concentration at Al/V ratio of 2, indicating a coordinate anionic mechanism of polymerization. NMR spectra were further used to confirm the mechanism of polymerization and stability of active sites responsible for isotacticity.     

Free-energy component analysis of 40 protein-DNA complexes: a consensus view on the thermodynamics of binding at the molecular level

Noncovalent association of proteins to specific target sites on DNA--a process central to gene expression and regulation--has thus far proven to be idiosyncratic and elusive to generalizations on the nature of the driving forces. The spate of structural information on protein--DNA complexes sets the stage for theoretical investigations on the molecular thermodynamics of binding aimed at identifying forces responsible for specific macromolecular recognition. Computation of absolute binding free energies for systems of this complexity transiting from structural information is a stupendous task. Adopting some recent progresses in treating atomic level interactions in proteins and nucleic acids including solvent and salt effects, we have put together an energy component methodology cast in a phenomenological mode and amenable to systematic improvements and developed a computational first atlas of the free energy contributors to binding in approximately 40 protein-DNA complexes representing a variety of structural motifs and functions. Illustrating vividly the compensatory nature of the free energy components contributing to the energetics of recognition for attaining optimal binding, our results highlight unambiguously the roles played by packing, electrostatics including hydrogen bonds, ion and water release (cavitation) in protein-DNA binding. Cavitation and van der Waals contributions without exception favor complexation. The electrostatics is marginally unfavorable in a consensus view. Basic residues on the protein contribute favorably to binding despite the desolvation expense. The electrostatics arising from the acidic and neutral residues proves unfavorable to binding. An enveloping mode of binding to short stretches of DNA makes for a strong unfavorable net electrostatics but a highly favorable van der Waals and cavitation contribution. Thus, noncovalent protein-DNA association is a system-specific fine balancing act of these diverse competing forces. With the advances in computational methods as applied to macromolecular recognition, the challenge now seems to be to correlate the differential (initial vs. final) energetics to substituent effects in drug design and to move from affinity to specificity.     

Polymerization of acrylonitrile with VCl4–Al(C2H5)3 catalyst system in presence of acetonitrile

The polymerization of acrylonitrile with the homogeneous catalyst system of VCl₄–AlEt₃ in acetonitrile at 40°C has been investigated. The rate of polymerization is found to be first-order with respect to monomer and inversely proportional to the catalyst concentration. The overall activation energy for this catalyst system is 10.97 kcal/mole. The inverse proportionality of rate of polymerization with the catalyst concentration is attributed to the permanent complex formation between the catalyst complex and acrylonitrile, and a reaction scheme is proposed.