Characterization of the Chemical Profile of Euphorbia Species from Turkey by Gas Chromatography–Mass Spectrometry (GC-MS), Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS), and Liquid Chromatography–Ion Trap–Time-of-Flight–Mass Spectrometry (LC-IT-TOF-MS) and Chemometric Analysis†

The Euphorbiaceae family comprises of about 300 genera and 5000 species primarily distributed in America and tropical Africa. The Euphorbia genus is represented by 105 species and locally named as “Sütle?en” and “Xa?îl” in Turkey. The present study aimed to determine the chemical constituents of E. aleppica, E. eriophora, E. macroclada, E. grisophylla, E. seguieriana subsp. seguieriana, E. craspedia, E. denticulata, E. falcata, and E. fistulosa, and classify them by utilizing the chemometric techniques of principal component analysis (PCA) and hierarchical cluster analysis (HCA). Linoleic acid, 17-tetratriacontane, palmitic acid, and hexatriacontane were the major fatty acids from the gas chromatography–mass spectrometry (GC/MS) analyses. Characterization of 268 constituents of the studied species was achieved by liquid chromatography–ion trap–time-of-flight–mass spectrometry (LC-IT-TOF-MS). Furthermore, a new liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantitative determination of 11 compounds (quinic acid, protocatechuic acid, rutin, hesperidin, eugenol, p-coumaric acid, piceatannol, scopoletin, dl-kavain, chrysophanic acid, and resiniferatoxin) in these species. The developed method was validated for the linearity, limit of detection, limit of quantification, repeatability, and recovery.     

On the Asymptotics of the Finite-Perimeter Partition Function of Two-Dimensional Lattice Vesicles

We derive the dominant asymptotic form and the order of the correction terms of the finite-perimeter partition function of self-avoiding polygons on the square lattice, which are weighted according to their area A as q^A, in the inflated regime, q >1. The approach qM 1⁺ of the asymptotic form is examined.     

Superparamagnetic behavior and AC-losses in NiFe2O4 nanoparticles

Crystallographic, microstructural and magnetic properties of NiFe₂O₄ nanoparticles synthesized by precipitation from nonaqueous solutions have been studied in the work. The transmission electron microscopy studies reveal particle sizes ∼5 nm for the as-prepared particles which increase up to ∼20 nm upon annealing at 500 °C. Quasistatic magnetic measurements show superparamagnetic behavior with blocking temperature below room temperature for both the as-prepared and annealed particles. Characteristic magnetic parameters of the particles including average magnetic moment of an individual nanoparticle and effective anisotropy constant have been determined. The specific loss power which is released on the exposure of an ensemble of synthesized particles to an electromagnetic field is calculated and measured experimentally.     

Turbulence regeneration in pipe flow at moderate Reynolds numbers

We present the results of an experimental investigation into the nature and structure of turbulent pipe flow at moderate Reynolds numbers. A turbulence regeneration mechanism is identified which sustains a symmetric traveling wave within the flow. The periodicity of the mechanism allows comparison to the wavelength of numerically observed exact traveling wave solutions and close agreement is found. The advection speed of the upstream turbulence laminar interface in the experimental flow is observed to form a lower bound on the phase velocities of the exact traveling wave solutions. Overall our observations suggest that the dynamics of the turbulent flow at moderate Reynolds numbers are governed by unstable nonlinear traveling waves.     

A Local Limit Theorem for Moderate Deviations

The purpose of this note is to establish a uniform estimatefor the mass function P(S_m = y) of an integer-valued randomwalk when y and where µ isthe mean of the step distribution. (The local central limittheorem provides such an estimate when ( is bounded.) The assumptions are that the mass functionp of the step distribution is regularly varying at with index–, where > 3, and that for some ' > 2. From this result, a ratio limit theorem isderived, and this in turn is applied to yield some new informationabout the space–time Martin boundary of certain randomwalks.