DBCS: A Decomposition Based Compressive Sensing for Event Oriented Wireless Sensor Networks

Wireless Personal Communications - Demarcating distributed event region is a key issue in various application domains of wireless sensor networks. In this paper, the problem of energy conservation...     

Interplay of Anion-π+ and π+-π+ Interactions in Novel Pyrido[2,1-a]isoquinolinium-Based AIEgens - Substituent- and Counterion-Dependent Fluorescence Modulation and Applications in Live Cell Mitochondrial Imaging**

Recently, the concept of anion-π⁺ interactions has witnessed unique applications in the field of AIEgen development. In this contribution, we disclose a consolidated study of a library of N-doped ionic AIEgens accessed through silver-mediated cyclization of pyridino-alkynes. A thorough photophysical, computational and crystallographic study has been conducted to rationalize the observed substituent- and counterion-dependent fluorescence properties of these luminogens. We further elucidate the prominent role of anion-π⁺ interactions, π⁺-π⁺ interactions and other non-covalent interactions, in inhibiting the undesired ACQ effect. Finally, we have also demonstrated the application of selected AIEgens for imaging of mitochondria in live cells.     

MPMAC: Clustering Based MAC Protocol for VANETs

Wireless Personal Communications - Vehicular safety messaging is warranted mostly in turbulent traffic situations in which even cluster based MAC protocols are beset by problems of cluster rupture,...     

Inhibitory Effect of Polyphenols from the Whole Green Jackfruit Flour against α-Glucosidase, α-Amylase,Aldose Reductase and Glycation at Multiple Stages and Their Interaction: Inhibition Kinetics and Molecular Simulations

For the first time, α-glucosidase, α-amylase, aldose reductase, and glycation at multiple stages inhibitory assays were used to explore the antidiabetic potential of whole unripe jackfruit (peel with pulp, flake, and seed). Two polyphenols (phenolic acids) with strong antihyperglycaemic activity were isolated from the methanol extract of whole jackfruit flour (MJ) using activity-guided repeated fractionation on a silica gel column chromatography. The bioactive compounds isolated were identified as 3-(3,4-Dihydroxyphenyl)-2-propenoic acid (caffeic acid: CA) and 4-Hydroxy-3,5-dimethoxybenzoic acid (syringic acid: SA) after various physicochemical and spectroscopic investigations. CA (IC₅₀: 8.0 and 26.90 µg/mL) and SA (IC₅₀: 7.5 and 25.25 µg/mL) were identified to inhibit α-glucosidase and α-amylase in a competitive manner with low Ki values. In vitro glycation experiments further revealed that MJ and its components inhibited each stage of protein glycation as well as the generation of intermediate chemicals. Furthermore, CA (IC₅₀: 3.10) and SA (IC₅₀: 3.0 µg/mL) inhibited aldose reductase effectively in a non-competitive manner, respectively. The binding affinity of these substances towards the enzymes examined has been proposed by molecular docking and molecular dynamics simulation studies, which may explain their inhibitory activities. The found potential of MJ in antihyperglycaemic activity via inhibition of α-glucosidase and in antidiabetic action via inhibition of the polyol pathway and protein glycation is more likely to be related to the presence of the phenolic compounds, according to our findings.     

Effect of Pr-filling in binary skutterudites CoX3 (P,As and Sb) on structural,electronic, elastic and transport properties

ABSTRACT

We have studied the effect on the structural, electronic, elastic and transport properties of binary skutterudite CoX₃ (X?=?P, As, Sb) after filling void spaces by Pr atoms. All the calculations are carried out using the full-potential linearised augmented plane wave (FP-LAPW) method within the generalised gradient approximation (GGA) viz, PBE, and PBEsol. In case of binary skutterudites, equilibrium lattice parameters obtained using PBEsol functional are in good agreement with the theoretical and experimental results. The Hubbard parameter (U) has been used with PBEsol-GGA functional to see its effect on the band structures of binary and ternary compounds. Filling of Pr atoms at void positions in binary skutterudites creates the gap between the valence and conduction band. The obtained values of the elastic constants show that CoX₃, PrCo₄X₁₂ (X?=?P, As, Sb) are mechanically stable and brittle. Mechanically, PrCo₄P₁₂ and PrCo₄As₁₂ are anisotropic, but PrCo₄Sb₁₂ is isotropic. Obtained saturated Seeback coefficients are approximate ?60?μV/K (PrCo₄P₁₂), ?80?μV/K (PrCo₄As₁₂) and ?68?μV/K (PrCo₄Sb₁₂) in the spin-up channel while in the spin-down channel corresponding values are ?10, ?50 and ?120?μV/K at 800?K, respectively. These values are higher in magnitude than that in the corresponding binary compounds.     

On the synthesis and characterization of La doped MgB2 superconductor

We report the synthesis of La doped MgB₂ superconductors with nominal compositions Mg_1‐xLa_xB₂ (with x = 0.01, 0.03, 0.05, 0.07) by solid state reaction at ambient pressure. A special encapsulation technique has been used by us to prepare high quality superconducting MgB₂ samples. The bulk polycrystalline samples possess superconducting transition temperature T_c(R=0) ranging between 36‐39 K. It has been found that transport critical current density J_c of the samples change significantly with the doping level of La. A high transport (J_c) value ∼1.9 x 10³ A/cm² at 15 K has been achieved for Mg_0.97La_0.03B₂ sample. The XRD and TEM investigations indicate that the samples prepared by encapsulation method are devoid of MgO, which is generally found when synthesis of MgB₂ is done through sintering of Mg and B powders. The detailed microstructural investigations of Mg_0.97La_0.03B₂ specimens by transmission electron microscopy (TEM) reveal the presence of partial dislocation network, moiré fringes and superlattice structure in the as synthesized samples. The higher transport critical current density observed in Mg_0.97La_0.03B₂ superconductor has been attributed to the partial dislocations which are capable of providing pinning centres. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Wireless Sensor Networks Localization Using Progressive Isomap

Wireless Personal Communications - This paper proposes a progressive Isomap algorithm for node localization. The algorithm is an extension of centralized Isomap and is capable of effectively...     

Activity of α‐Chymotrypsin in Cationic and Nonionic Micellar Media: Ultraviolet and Fluorescence Spectroscopic Approach

α‐Chymotrypsin (α‐CT) activity was measured in aqueous buffer with the following alkyltriphenylphosphonium bromide surfactants in the series cetyl, tetradecyl, and dodecyl as a tail length. For the sake of comparison with mixed micellar investigation on activity of α‐CT, cationic cetyltriphenylphosphonium bromide (CTPB) and nonionic surfactant Triton X‐100, Brij‐56, Brij‐35, Tween 20, and Igepal Co‐210 have been used. The p‐nitrophenyl acetate (PNPA) hydrolysis rate was determined at the surfactant concentration of both cationic and mixed micellar systems by a UV–vis spectrophotometer. The catalytic reaction follows the Michaelis–Menten mechanism, and the catalytic efficiency (k_cat/K_M) was evaluated for both homogeneous and mixed‐micellar media. The maximum catalytic efficiency was observed at 5 mM concentration of CTPB, but the highest catalytic efficiency, 572 M^?1 s^?1, was measured in the presence of mixed micellar (7.5 mM CTPB + 2.5 mM Tween‐20). The fluorescence (FL) spectra showed the differences of α‐CT conformations in the presence of cationic surfactants. The FL results suggest that the influence of cationic surfactant on proteolysis arises from the interaction with the α‐CT. The binding constant, k_sv, of α‐CT with cationic aggregates was determined in the buffer using the Stern–Volmer equation by the fluorescence spectroscopic approach.