Analytical solutions of nonlinear system of fractional-order Van der Pol equations

Nonlinear Dynamics - The double-well, in-phase and out-of-phase periodic solutions of the system of fractional-order Van der Pol equations and the exact solution of the nonlinear fractional-order...     

Automatic white matter lesion segmentation using an adaptive outlier detection method

White matter (WM) lesions are diffuse WM abnormalities that appear as hyperintense (bright) regions in cranial magnetic resonance imaging (MRI). WM lesions are often observed in older populations and are important indicators of stroke, multiple sclerosis, dementia and other brain-related disorders. In this paper, a new automated method for WM lesions segmentation is presented. In the proposed method, the presence of WM lesions is detected as outliers in the intensity distribution of the fluid-attenuated inversion recovery (FLAIR) MR images using an adaptive outlier detection approach. Outliers are detected using a novel adaptive trimmed mean algorithm and box-whisker plot. In addition, pre- and postprocessing steps are implemented to reduce false positives attributed to MRI artifacts commonly observed in FLAIR sequences. The approach is validated using the cranial MRI sequences of 38 subjects. A significant correlation (R=0.9641, P value=3.12×10(-3)) is observed between the automated approach and manual segmentation by radiologist. The accuracy of the proposed approach was further validated by comparing the lesion volumes computed using the automated approach and lesions manually segmented by an expert radiologist. Finally, the proposed approach is compared against leading lesion segmentation algorithms using a benchmark dataset.     

Spectroscopic Studies and Crystal Structure of 1-[(2,5-dioxopyrrolidin-1-yl)(phenyl) methyl] Thiourea

Abstract  A new mannich base 1-[(2,5-dioxopyrrolidin-1-yl)(phenyl)methyl] thiourea formed by the direct condensation of thiourea, succinimide and benzaldehyde has been synthesized. The structure of this mannich base has been elucidated on the basis of micro elemental analysis, IR, ¹H NMR, ¹³C NMR, Mass and UV–Visible Techniques. The crystal structure of the title compound C₁₂ H₁₃ N₃ O₂ S was determined. It crystallizes in the monoclinic system, space group P2₁/c with a = 10.8234 (7) ?, b = 6.0355 (5) ?, c = 19.3692 (14) ?, β = 100.540(3)°, Z = 4 and V = 1243.94 (16) ?³. The structure was solved by the full-matrix least squares on F ² and had a refined R value of 0.0465 for 1,964 observed reflections. The crystal structure is stabilized by strong intramolecular C–H···O, C–H···S interactions and inter molecular N–H···O and S···S interactions. Graphical Abstract  This paper describes the spectroscopic and crystallographic studies of the title compound which is essential in ascertaining the structure of this new compound.      

Spectroscopic Studies and Crystal Structure of 1-(Morpholino (Phenyl) Methyl) Pyrrolidine-2,5-Dione

Abstract  

A new mannich base 1-(morpholino(phenyl)methyl)pyrrolidine-2,5-dione formed by the direct condensation of morpholine, succinimide and benzaldehyde has been synthesized. The structure of this mannich base has been elucidated on the basis of micro elemental analysis, IR, ¹H NMR, ¹³C NMR, UV–Visible Techniques and Mass. The crystal structure of the title compound C₁₅ H₁₈ N₂ O₃ was determined. It crystallizes in the triclinic system, space group P − 1, with a = 8.8122(13) ?, b = 9.2794(14) ?, c = 9.814 (3) ?, α = 107.154(9)°, β = 97.936(9)°, γ = 110.197(7)°,V = 693.4(2) ?³, D _x  = 1.314 Mg/m³. The structure was solved by the full-matrix least squares on F² and had a refined R value of 0.0486 for 8567 observed reflections. The six membered heterocyclic ring of the morpholino moiety adopts a chair conformation. The crystal structure is stabilized by weak intermolecular C–H···O interactions that link the molecules into inversion dimers.     

Understanding anion transport in an aminated trimethyl polyphenylene with high anionic conductivity

An alkaline exchange membrane (AEM) based on an aminated trimethyl poly(phenylene) is studied in detail. This article reports hydroxide ion conductivity through an in situ method that allows for a more accurate measurement. The ionic conductivities of the membrane in bromide and carbonate forms at 90 °C and 95% RH are found to be 13 and 17 mS cm⁻¹ respectively. When exchanged with hydroxide, conductivity improved to 86 mS cm⁻¹ under the same experimental conditions. The effect of relative humidity on water uptake and the SAXS patterns of the AEM membranes were investigated. SAXS analysis revealed a rigid aromatic structure of the AEM membrane with no microphase separation. The synthesized AEM is shown to be mechanically stable as seen from the water uptake and SAXS studies. Diffusion NMR studies demonstrated a steady state long-range diffusion constant, D_∞ of 9.8 × 10⁻⁶ cm² s⁻¹ after 50–100 ms. © 2012 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1743–1750, 2013     

Cluster pre-existence probability

Pre-existence probability of the fragments for the complete binary spectrum of different systems such as ⁵⁶Ni, ¹¹⁶Ba, ²²⁶Ra and ²⁵⁶Fm are calculated, from the overlapping part of the interaction potential using the WKB approximation. The role of reduced mass as well as the classical hydrodynamical mass in the WKB method is analysed. Within WKB, even for negative Q -value systems, the pre-existence probability is calculated. The calculations reveal rich structural information. The calculated results are compared with the values of preformed cluster model of Gupta and collaborators. The mass asymmetry motion is shown here for the first time as a part of relative separation motion.     

ZnO/PBAT nanocomposite films: Investigation on the mechanical and biological activity for food packaging

Packaging of foods in high barrier materials is essential to attain food safety. Nanocomposite technology is leading in search of the earlier said kind of packaging materials. The role of zinc oxide (ZnO) loadings on poly(butylene adipate‐co‐terephthalate) (PBAT) structure were investigated, in addition to that packaging properties such as barrier, thermal, and mechanical properties were studied. Antimicrobial films are developed based on PBAT and ZnO nanoparticles. The nanocomposites exhibits a significant increase in the mechanical and thermal stability. The resulting PBAT/ZnO nanofilms show superior antimicrobial activity against Escherichia coli and Staphylococcus aureus. Copyright © 2016 John Wiley & Sons, Ltd.     

Determination of neptunium using high resolution sequential ICP-AES

In view to separate La(III), Pr(III) and U(VI) ions, from aqueous solutions, batch experiments are carried out for the sorption and desorption of these ions onto and from a novel functionalized resin. The sorption capacities varied from 1.06 to 47.30 mg/g and increased in the following order La(III), Pr(III) and U(VI), while yields desorption ranged from 73.0 to 94.3% and increased in the following order Pr(III), La(III) and U(VI). Considering the largest difference in sorption capacity and desorption yield of these three elements, at different operates conditions, this material can be potential candidate for the separation of U(VI), Pr(III) and La(III) ions from nuclear and other industrial wastewater.     

Protein polymer conjugates: improving the stability of hemoglobin with poly(acrylic acid)

The synthesis, characterization, and evaluation of a novel polymer-protein conjugate are reported here. The covalent conjugation of high-molecular weight poly(acrylic acid) (PAA) to the lysine amino groups of met-hemoglobin (Hb) resulted in the covalent conjugation of Hb to PAA (Hb-PAA conjugate), as confirmed by dialysis and electrophoresis studies. The retention of native-like structure of Hb in Hb-PAA was established from Soret absorption, circular dichroism studies, and the redox activity of the iron center in Hb-PAA. The peroxidase-like activities of the Hb-PAA conjugate further confirmed the retention of Hb structure and biological activity. Thermal denaturation of the conjugate was investigated by differential scanning calorimetry and steam sterilization studies. The Hb-PAA conjugate indicated an improved denaturation temperature (T(d)) when compared to that of the unmodified Hb. One astonishing observation was that polymer conjugation significantly enhanced the Hb-PAA storage stability at room temperature. After 120 h of storage at room temperature in phosphate-buffered saline (PBS) at pH 7.4, for example, Hb-PAA retained 90% of its initial activity and unmodified Hb retained <60% of its original activity under identical conditions of buffer, pH, and temperature. Our conjugate demonstrates the key role of polymers in enhancing Hb stability via a very simple, efficient, general route. Water-swollen, lightly cross-linked, stable Hb-polymer nanogels of 100-200 nm were produced quickly and economically by this approach for a wide variety of applications.