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.     

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.     

Photophysical characteristics and density functional theory calculations of indole 2-carboxylic acid in the presence of mercurous ions

Many photo-physical studies have been reported for the detection of Hg²⁺ ions. Here we present the effect of Hg ₂ ²⁺ ions on the absorption and fluorescence of indole-2-carboxylic acid (I2C). Experimental evidence, supported by density functional theory B3LYP/LANL2DZ/PCM, for the formation of a I2C-Hg ₂ ²⁺ complex, is reported for the first time. It was observed that I2C forms a ground-state complex with Hg ₂ ²⁺ ions in a ratio of 3:1. The possibility of I2C to be used as a selective novel chemical sensor for the spectrophotometric detection of mercurous ions is described.     

Gold nanoparticle networks with photoresponsive interparticle spacings

Photoresponsive gold nanoparticle networks were prepared by functionalizing them with azobenzene derivatives. A network can be formed when a linker molecule constituting the azobenzene moiety suitably derivatized on either side with gold surface sensitive groups such as thiols and amines is added to the nanoparticle solution. It is shown that the interparticle spacing in the networks could be controlled by the reversible trans-cis isomerization of the azobenzene moiety induced by UV and visible light, respectively. The photoinduced variation in the interparticle spacings is inferred by the changes in the optical spectra of the gold nanoparticles which display a red or blue shift in the surface plasmon resonance peak depending on a decrease or increase in the interparticle spacing, respectively. Transmission electron microscopy images are in consonance with the evidence from the optical spectra.     

Synthesis of silver nanoprisms in formamide

Polygonal (mainly triangular) silver nanoprisms were prepared by reducing silver perchlorate in formamide in the presence of polyethylene glycol (PEG) at room temperature. The reduction of silver ions by formamide leads to the deposition of arrays of triangular shaped silver nanoparticles on the glass walls of the container, accompanied by evolution of CO2 gas. In the presence of poly(N-vinyl-2-pyrrolidone) (PVP) and PEG (1:1), both nanospheres and nanoprisms are formed.     

Principles of rapid polymerase chain reactions: mathematical modeling and experimental verification

Polymerase chain reaction (PCR) is an important diagnostic tool for the amplification of DNA. The PCR process can be treated as a problem in biochemical engineering. This study focuses on the development of a mathematical model of the polymerase chain reaction. The PCR process consists of three steps: denaturation of target DNA, annealing of sequence-specific oligonucleotide primers and the enzyme-catalyzed elongation of the annealed complex (primer:DNA:polymerase). The denaturation step separates the double strands of DNA; this model assumes denaturation is complete. The annealing step describes the formation of a primer-fragment complex followed by the attachment of the polymerase to form a ternary complex. This step is complicated by competitive annealing between primers and incomplete fragments including primer-primer reactions. The elongation step is modeled by a stochastic method. Species that compete during the elongation step are deoxynucleotide triphosphates dCTP, dATP, dTTP, dGTP, dUTP, and pyrophosphate. Thermal deamination of dCTP to form dUTP is included in the model. The probability for a species to arrive at the active site is based on its molar fraction. The number of random insertion events depends on the average processing speed of the polymerase and the elongation time of the simulation. The numerical stochastic experiment is repeated a sufficient number of times to construct a probability density distribution (PDF). The moment of the PDF and the annealing step products provide the product distribution at the end of the elongation step. The overall yield is compared to six experimental values of the yield. In all cases the comparisons are very good.