On Brown’s constant associated with irreducible polynomials over henselian valued fields

Let v be a henselian valuation of arbitrary rank of a field K and be the prolongation of v to the algebraic closure of K with value group . In 2008, Ron Brown gave a class P of monic irreducible polynomials over K such that to each g(x) belonging to P, there corresponds a smallest constant λ_g belonging to (referred to as Brown’s constant) with the property that whenever is more than λ_g with K(β) a tamely ramified extension of (K,v), then K(β) contains a root of g(x). In this paper, we determine explicitly this constant besides giving an important property of λ_g without assuming that K(β)/K is tamely ramified.     

Biosynthesis of nanoparticles: technological concepts and future applications

Nanotechnology involves the production, manipulation and use of materials ranging in size from less than a micron to that of individual atoms. Although nanomaterials may be synthesized using chemical approaches, it is now possible to include the use of biological materials. In this review, we critically assess the role of microorganisms and plants in the synthesis of nanoparticles.     

A Characterization of Finite Tame Extensions

Let v be a henselian valuation of a field K. In this paper itis proved that any finite extension (K', v') of (K, v) is tameif and only if there exists 0 in K' such that v'() = v(Tr_K'/K())using elementary results of valuation theory. A special caseof this result, when the characteristic of the residue fieldof v is p > 0 and (K', v')/(K, v) is an extension of degreep, was proved in 1990 by J. P. Tignol (J. Reine Angew. Math.404 (1990) 1–38). 1991 Mathematics Subject Classification12J10, 12J25, 13A18.     

Response Surface Methodology: Photocatalytic Degradation Kinetics of Basic Blue 41 Dye Using Activated Carbon with TiO2

Water decontamination still remains a major challenge to some developing countries not having centralized wastewater systems. Therefore, this study presents the optimization of photocatalytic degradation of Basic Blue 41 dye in an aqueous medium by an activated carbon (AC)-TiO₂ photocatalyst under UV irradiation. The mesoporous AC-TiO₂ synthesized by a sonication method was characterized by X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy for crystal phase identification and molecular bond structures, respectively. The efficiency of the AC-TiO₂ was evaluated as a function of three input variables viz. catalyst load (2–4 g), reaction time (15–45 min) and pH (6–9) by using Box-Behnken design (BBD) adapted from response surface methodology. Using color and turbidity removal as responses, a 17 run experiment matrix was generated by the BBD to investigate the interaction effects of the three aforementioned input factors. From the results, a reduced quadratic model was generated, which showed good predictability of results agreeable to the experimental data. The analysis of variance (ANOVA), signposted the selected models for color and turbidity, was highly significant (p < 0.05) with coefficients of determination (R²) values of 0.972 and 0.988, respectively. The catalyst load was found as the most significant factor with a high antagonistic impact on the process, whereas the interactive effect of reaction time and pH affected the process positively. At optimal conditions of catalyst load (2.6 g), reaction time (45 min), and pH (6); the desirability of 96% was obtained by a numerical optimization approach representing turbidity removal of 93% and color of 96%.     

Velogenic Newcastle Disease Virus as an Oncolytic Virotherapeutics: In Vitro Characterization

Cancer is one of the killer diseases in humans and needs alternate curative measures despite recent improvement in modern treatment modalities. Oncolytic virotherapy seems to be a promising nonconventional way to treat cancers. Newcastle disease virus (NDV), a poultry virus, is nonpathogenic to human and domestic animals and has a long history of being used in oncotherapy research in several preclinical studies. The ability of NDV to successfully infect and destroy cancer cells is dependent on the strain and the pathotype of the virus. Adaptation of viruses to heterologous hosts without losing its replicative and oncolytic potential is prerequisite for use as cancer virotherapeutics. In the present study, velogenic NDV was adapted for replication in HeLa cells, and its cytotoxic potential was evaluated by observing morphological, biochemical, and nuclear landmarks of apoptosis. Our results indicated that the NDV-induced apoptosis in HeLa cells was dependent on upregulation of TNF-related apoptosis-inducing ligand (TRAIL) and caspases activation. Different determinants of apoptosis evaluated in the present study indicated that this strain could be a promising candidate for cancer therapy in future.     

Evaluation of jatropha oil to produce poly(3-hydroxybutyrate) by Cupriavidus necator H16

Jatropha oil, a non-edible vegetable oil, may be an alternative substrate to food-grade oils for bioplastic production. Jatropha oil contains 93.9% palmitic acids, oleic acids and linoleic acids. High P(3HB) accumulation of 87 wt% from 13.1 g/L of cell dry weight (CDW) was obtained by Cupriavidus necator H16 when 12.5 g/L of jatropha oil and 0.54 g/L of urea were used. Lipase activity increased in the initial stages of P(3HB) production, when 1 g/L of jatropha oil was added to the preculture medium. Addition of oil in preculture did not affect final CDW or P(3HB) accumulation. P(3HB) production in a 10 L lab-scale fermenter gave a yield of 0.78 g P(3HB) per g jatropha oil used after 48 h. For the first time, this study proved that jatropha oil is a feasible and excellent carbon source for P(3HB) biosynthesis by C. necator H16 with potential for large-scale production. The toxins in jatropha oil did not affect the P(3HB) biosynthesis.     

Spectral narrowing and stabilization of thulium fiber lasers using guided-mode resonance filters

We used guided-mode resonance filters (GMRFs), fabricated using thin-film deposition and chemical etching, as intracavity feedback elements to stabilize and narrow the output spectrum in thulium-doped fiber oscillators operating in the 2?μm wavelength regime, producing linewidths of <700?pm up to 10?W power levels. A Tm fiber-based amplified spontaneous emission source was used to characterize the reflective properties of the GMRFs. Linewidths of 500?pm and a 7.3?dB reduction in transmission were measured on resonances.