Differential content of secondary metabolites in diploid and tetraploid cytotypes of Siegesbeckia orientalis L.

Siegesbeckia orientalis L. is an annual herb widely distributed throughout the world and has many medicinal properties. In Chinese traditional system, it is popularly known as Xi-Xian and used for its anti-inflammatory properties. In the present study, two cytotypes (diploid and tetraploid) have been investigated for their secondary metabolites. The different plant parts have been explored in terms of total phenolics, total flavonoids, DPPH radical scavenging acitivity and total antioxidant capacity. Out of different plant parts, leaves have the maximum amount of secondary metabolites and antioxidant potential. HPTLC technique has been applied to quantify six marker compounds in the two cytotypes. Tetraploid cytotype has been compared with diploid cytotype, which shows that tetraploid has the maximum amount of studied secondary metabolites with high antioxidant potential.     

Modified o-methyl-substituted IBX: room temperature oxidation of alcohols and sulfides in common organic solvents

o-Methyl-substituted Me-IBX is the first modified analog of IBX that oxidizes alcohols in common organic solvents at room temperature, due to a composite of two factors, that is, low solubility and hypervalent twisting-promoted rate enhancement. Furthermore, the reagent is efficient for selective oxidation of sulfides to sulfoxides, a transformation that otherwise occurs only sluggishly with standard IBX. The facile synthetic accessibility and its mild as well as non-hazardous nature render Me-IBX a stable equivalent of Dess-Martin periodinane reagent in organic oxidations.     

Comparing the structural topology of integral and peripheral membrane proteins utilizing electron paramagnetic resonance spectroscopy

The alignment of membrane proteins provides pertinent structural and dynamic information. Structural topology data gleaned from such studies can be used to determine the functional mechanisms associated with a wide variety of integral membrane proteins. In this communication, we successfully demonstrate, for the first time, the determination of the structural topology and helical tilt of an antimicrobial peptide magainin 2 using aligned X-band spin-label EPR spectroscopic techniques. This novel comparison unlocks many possibilities utilizing EPR spectroscopy to probe antimicrobial peptide topologies with increased sensitivity and may also give further clues to elucidate their corresponding mechanisms.     

Modeling the sorption kinetics of divalent metal ions onto mineral adsorbent using integral method

A mathematical model has been developed that could predict kinetic parameters for the adsorption of divalent cations (lead, copper and zinc) onto low-grade rock phosphate using experimental data. The experiments were conducted with the initial concentrations of metal ions ranging from 10 to 100 mg/L. The mathematical model is based on application of Freundlich isotherm to mass transfer across the film surrounding the adsorbent. A code in C programming is used to numerically integrate the model equation, and to obtain the best simulated values of Freundlich constants K, N, order of reaction n, and film transfer coefficient, alpha. It is observed that the adsorption of metal ions on rock phosphate is more sensitive to N,n, and alpha in comparison to K, and lead is adsorbed more favorably than copper and zinc.     

Exploring the Antibacterial and Antibiofilm Efficacy of Silver Nanoparticles Biosynthesized Using Punica granatum Leaves

The current research work illustrates an economical and rapid approach towards the biogenic synthesis of silver nanoparticles using aqueous Punica granatum leaves extract (PGL-AgNPs). The optimization of major parameters involved in the biosynthesis process was done using Box-Behnken Design (BBD). The effects of different independent variables (parameters), namely concentration of AgNO₃, temperature and ratio of extract to AgNO_3, on response viz. particle size and polydispersity index were analyzed. As a result of experiment designing, 17 reactions were generated, which were further validated experimentally. The statistical and mathematical approaches were employed on these reactions in order to interpret the relationship between the factors and responses. The biosynthesized nanoparticles were initially characterized by UV-vis spectrophotometry followed by physicochemical analysis for determination of particle size, polydispersity index and zeta potential via dynamic light scattering (DLS), SEM and EDX studies. Moreover, the determination of the functional group present in the leaves extract and PGL-AgNPs was done by FTIR. Antibacterial and antibiofilm efficacies of PGL-AgNPs against Gram-positive and Gram-negative bacteria were further determined. The physicochemical studies suggested that PGL-AgNPs were round in shape and of ~37.5 nm in size with uniform distribution. Our studies suggested that PGL-AgNPs exhibit potent antibacterial and antibiofilm properties.     

Strong Law of Large Numbers for Betti Numbers in the Thermodynamic Regime

Journal of Statistical Physics - We establish the strong law of large numbers for Betti numbers of random ?ech complexes built on $${\mathbb {R}}^N$$ -valued binomial point processes and...     

Synthesis, spectral and biological studies of nitrogen–sulphur donor macrocyclic ligands and their transition metals complexes

Mn(II), Co(II), Ni(II) and Cu(II) complexes have been synthesized with 22 and 24 membered tetramide macrocyclic ligands viz; 1,9,12,20-tetraaza-2,8,13,19-tetraone-5,16-dithiacyclodocosane [L¹] and 1,9,13,21-tetraaza-2,8,14,20-tetraone-5,17-dithiacyclotetracosane [L²] and characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, electronic EPR spectral studies and electrochemical properties. The molar conductance of all the complexes in DMSO solution is corresponding to 1:2 electrolyte. Thus these complexes may be formulated as [M(L′)]Cl₂ [where M = Mn(II), Co(II), Ni(II) and Cu(II) L′ = L¹ and L²]. On the basis of spectral studies a distorted octahedral geometry has been assigned for all the complexes. The ligands and their complexes were also screened in vitro against two pathogenic fungi (F. moniliformae and R. solani) to assess their growth inhibiting potential.     

Experimental study of bubble departure characteristics in forced convective subcooled nucleate boiling

Visualization experiments in upward forced convective nucleate boiling flows were carried out. The bubble growth and collapse have been measured using high-speed photography technique with distilled water under atmospheric pressure. The experiments show that the bubbles depart from nucleating sites shortly after nucleation and slide along the heater surface. The bubbles grow while sliding, attain a maximum size, then lift from the surface sometime during condensation, and quickly vanish in the bulk liquid. Parametric studies show that bubble diameter and departure frequency increases with an increase in heat flux, a decrease in subcooling, and a decrease in mass flux.     

Effect of BaO on the crystallization kinetics of glasses along the Diopside-Ca-Tschermak join

We report on the effect of BaO on the crystallization kinetics of glasses in the diopside (CaMgSi₂O₆)-Ca-Tschermak (CaAl₂SiO₆) system. Partial substitution (i.e. 5%, 10% and 20%) of Ba²⁺ for Ca²⁺ was attempted in composition CaMg_0.8Al_0.4Si_1.8O₆, in three different glasses while partial substitution of B³⁺ for Al³⁺ was made in the fourth glass. Structural investigations on the glasses have been made by density measurements, molar volume and Infra-red spectroscopy (FTIR). Non-isothermal crystallization kinetic studies have been employed to study the mechanism of crystallization in all the four glasses. The Avrami parameter for the glass powders is ∼2, indicating the existence of intermediate mechanism of crystallization. Crystallization sequence in the glasses has been followed by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and FTIR. Augite crystallized out being the dominant phase in all the glass-ceramics, while different polymorphs of BaAl₂Si₂O8 were present as secondary or minor phases.     

Theoretical and Experimental Study of Long-Period Grating Refractive Index Sensor

Abstract

This article presents the theoretical and experimental investigation of the response of long-period gratings as a refractive index sensor. Cladding modes are calculated, and results are compared with Optigrating 4.2.2 (Optiwave Systems Inc., Ottawa, Canada). The response has been checked for refractive indices ranging from 1 to 1.458. Theoretically simulated results are in accordance with the experimental results. It was found that the software package calculated values correctly up to the seventh decimal point. The ambient refractive index response of a long-period grating over a much wider index range has been modeled for values both less and more than the cladding refractive index.