Dynamics of a family of transcendental meromorphic functions having rational Schwarzian derivative

In the present paper, a class F of critically finite transcendental meromorphic functions having rational Schwarzian derivative is introduced and the dynamics of functions in one parameter family is investigated. It is found that there exist two parameter values λ^∗=?(0)>0 and , where and is the real root of ?^′(x)=0, such that the Fatou sets of fλ(z) for λ=λ^∗ and λ=λ∗∗ contain parabolic domains. A computationally useful characterization of the Julia set of the function fλ(z) as the complement of the basin of attraction of an attracting real fixed point of fλ(z) is established and applied for the generation of the images of the Julia sets of fλ(z). Further, it is observed that the Julia set of fλ∈K explodes to whole complex plane for λ>λ∗∗. Finally, our results found in the present paper are compared with the recent results on dynamics of one parameter families λtanz, [R.L. Devaney, L. Keen, Dynamics of meromorphic maps: Maps with polynomial Schwarzian derivative, Ann. Sci. École Norm. Sup. 22 (4) (1989) 55-79; L. Keen, J. Kotus, Dynamics of the family λtan(z), Conform. Geom. Dynam. 1 (1997) 28-57; G.M. Stallard, The Hausdorff dimension of Julia sets of meromorphic functions, J. London Math. Soc. 49 (1994) 281-295] and , λ>0 [G.P. Kapoor, M. Guru Prem Prasad, Dynamics of : The Julia set and bifurcation, Ergodic Theory Dynam. Systems 18 (1998) 1363-1383].     

Gain-of-function mutational activation of human tRNA synthetase procytokine

Disease-causing mutations occur in genes for aminoacyl tRNA synthetases. That some mutations are dominant suggests a gain of function. Native tRNA synthetases, such as tyrosyl-tRNA synthetase (TyrRS) and tryptophanyl-tRNA synthetase, catalyze aminoacylation and are also procytokines that are activated by natural fragmentation. In principle, however, gain-of-function phenotypes could arise from mutational activation of synthetase procytokines. From crystal structure analysis, we hypothesized that a steric block of a critical Glu-Leu-Arg (ELR) motif in full-length TyrRS suppresses the cytokine activity of a natural fragment. To test this hypothesis, we attempted to uncover ELR in the procytokine by mutating a conserved tyrosine (Y341) that tethers ELR. Site-specific proteolytic cleavage and small-angle X-ray scattering established subtle opening of the structure by the mutation. Strikingly, four different assays demonstrated mutational activation of cytokine functions. The results prove the possibilities for constitutive gain-of-function mutations in tRNA synthetases.     

Single Crystal X-ray Study of 6-Phenyl-4-(p-tolyl)pyridin-2(1H)-one

Crystallography Reports - The title compound 6-phenyl-4-(p-tolyl)pyridin-2(1H)-one was synthesized via one-pot, three component reaction of (E)-1-phenyl-3-(p-tolyl)-2-propen-1-one, ethyl...     

Effective chemical route for the synthesis of silver nanostructures in formamide

Poly(N-vinyl-2-pyrrolidone) (PVP) and gelatin protected silver nanostructures are prepared in formamide by simple chemical route. Both PVP and gelatin stabilized silver nanoparticles in formamide lead to the formation of nanostructures of various definite geometric shapes and sizes. The effect of anisotropy on the surface plasmon absorption band is analyzed by monitoring the UV-Visible absorption spectra of gelatin stabilized silver nanoparticles. The particles were characterized by UV-Visible absorption spectra and TEM.     

Modify SRS-induced crosstalk with variety of fiber in SCM–WDM transmission links

In this paper, the SRS-induced crosstalk has been evaluated in a SCM–WDM communication links at different modulation frequencies and transmission lengths for variety of fiber. Results show that SRS-induced crosstalk dominates at low frequency. As the dispersion and effective area of fiber (A_eff) decreases, initially the crosstalk remains high and then it decreases with increase in modulation frequency. The present work shows that out of five different types of fiber, standard single mode fiber (SMF) has minimum crosstalk (−78 to −38) dB, (−55 to −33) dB and (−46 to −34) dB at modulation frequencies, transmission lengths and optical powers. Dispersion compensation fiber (DCF) has maximum crosstalk (−60 to −12) dB, (−37 to −12) dB and (−27 to −12) dB at modulation frequencies and transmission lengths.     

Analysis of surface and guided wave plasmon polariton modes in insulator–metal–insulator planar plasmonic waveguides

Theoretical and experimental study of the surface plasmon–polariton and guided wave plasmon polariton modes is presented for the Sapphire/Ag/Polycarbonate/Air structure. Theoretical results are obtained by solving complex multilayer eigenvalue equations as well as the reflectivity equation for this structure. It is proposed that the mode attenuation can be significantly reduced by inserting a low index dielectric buffer between the metal and the guiding dielectric layer. The dispersion and attenuation curves are generated. Both the surface plasmon and guided wave plasmon polariton modes are studied experimentally. The experimental values of the effective refractive indices agree well with the theoretical values. The electric field profiles are generated and used to examine the nature of modes. After optimization of various parameters the condition for low loss single mode guiding is obtained for the proposed structure. Effect of metal thickness on surface plasmon mode is also discussed. It is inferred that in a properly optimized plasmonic waveguide, the losses can be reduced by a factor of 4.     

Pyrene-fluorene hybrids containing acetylene linkage as color-tunable emitting materials for organic light-emitting diodes

New blue- to yellow-emitting materials have been developed by incorporating fluorene-based chromophores on pyrene core with acetylene linkage and using multifold palladium-catalyzed cross-coupling reactions. Both mono- and tetrasubstituted derivatives have been synthesized and characterized. The tetrasubstituted derivatives displayed red-shifted emission when compared to the monosubstituted derivative indicative of an extended conjugation in the former. End-capping with a diphenylamine unit further red-shifted the absorption and emission profiles and imparted a weak dipolar character to the molecules. Amine-containing derivatives displayed positive solvatochromism in the fluorescence spectra indicating a more polar excited state due to an efficient charge migration from the diphenylamine donor to the pyrene π-acceptor. All of the derivatives were tested as emitting dopants with host material 4,4'-bis(9H-carbazol-9-yl)biphenyl (CBP) in a multilayered OLED and found to exhibit bright blue or yellow electroluminescence. The device utilizing 1,3,6,8-tetrasubstituted pyrene derivative as a dopant emitter displayed highest maximum luminescence 4630 cd/m(2) with power efficiency 3.8 lm/W and current efficiency 7.1 cd/A at 100 cd/m(2) attributable to the proper alignment of energy levels that led to the efficient harvesting of excitons. All of the devices exhibited color purity over a wide range of operating voltages.     

Numerical investigation of natural convection in a rectangular enclosure due to partial heating and cooling at vertical walls

A comprehensive numerical investigation on the natural convection in a rectangular enclosure is presented. The flow is induced due to the constant partial heating at lower half of the left vertical wall and partial cooling at upper half of the right vertical wall along with rest walls are adiabatic. In this investigation the Special attention is given to understand the effect of aspect ratio and heat source intensity i.e. Rayleigh number, Ra, on the fluid flow configuration as well as on the local and average heat transfer rates. The range of Rayleigh (Ra) and aspect ratio (A) is taken [10³, 10⁶] and [0.5, 4] respectively. The results are presented in terms of stream function (ψ), temperature (θ) and heat transfer rates (local Nusselt numbers Nu_L, and average Nusselt numbers Nu). The numerical experiments show that increasing of Ra implies the enhancement of thermal buoyancy force, which in turn increases the thermal convection in the cavity. As a result, the local as well as average heat transfer rate is expected to increase. The local transfer rate (Nu_L) is increases in the small region near the left vertical wall of the left wall of the cavity and after that it is decreases in the middle portion of heated region. And, it start to increase near to the middle point of left wall. It is also observed that the local heat transfer is increases as increases the aspect ratio. The average heat transfer rate (Nu) is increases as the aspect ratio A increases from 0.5 to 1 and beyond that it is decreases smoothly. It is also found that the heat transfer rate attains its maximum value at aspect ratio one.     

Numerical method for advection diffusion equation using FEM and B-splines

In the present work, a comprehensive study of advection–diffusion equation is made using B-spline functions. Advection–diffusion equation has many physical applications such as dispersion of dissolved salts in groundwater, spread of pollutants in rivers and streams, water transfer, dispersion of tracers, and flow fast through porous media. Motivation behind the proposed scheme is to present a solution scheme which is easy to understand. Both linear and quadratic B-spline functions have been used in the present work to understand the basic aspect and advantages of the presented scheme. Along with this, some test examples are studied to observe the correctness of the numerical experiments. Finally, different comparisons are made to cross check the results obtained by the given scheme.     

Measurement of στ product of solid state laser materials by an alternative method: Application to Nd3+ doped YVO4 crystal for 4 F 3/2→4 I 11/2 transition

In this paper an alternative approach for measurement of στ product for ⁴ F _3/2→⁴ I _11/2 transition of Nd³⁺ doped YVO₄ crystal is reported. In this method a microchip laser is formed by keeping a small piece of the sample in plane-plane resonator and a diode laser (808 nm) is used for pumping. The pump power induced thermal lensing effect is used to make the cavity stable. The cavity mode area is estimated by measuring the thermal lens focal length at the threshold and the average pump area is measured by Gaussian fit to the intensity profiles of the pump beam. The value of στ product of Nd:YVO₄ crystal obtained by this method is within 10% of the reported values. The advantage of this method is that it is a simple method for direct measurement of στ product of laser crystals.