Development of 1-Hydroxy-2(1H)-quinolone-Based Photoacid Generators and Photoresponsive Polymer Surfaces

A new class of carboxylate and sulfonate esters of 1-hydroxy-2(1H)-quinolone has been demonstrated as nonionic photoacid generators (PAGs). Irradiation of carboxylates and sulfonates of 1-hydroxy-2(1H)-quinolone by UV light (λ≥310?nm) resulted in homolysis of weak N?O bond leading to efficient generation of carboxylic and sulfonic acids, respectively. The mechanism for the homolytic N?O bond cleavage was supported by time-dependent DFT calculations. Photoresponsive 1-(p-styrenesulfonyloxy)-2-quinolone-methyl methacrylate (SSQL-MMA) and 1-(p-styrenesulfonyloxy)-2-quinolone-lauryl acrylate (SSQL-LA) copolymers were synthesized from PAG monomer 1-(p-styrenesulfonyloxy)-2-quinolone, and subsequently controlled surface wettability was demonstrated for the above-mentioned photoresponsive polymers.     

Dilaton Dark Energy Model in f(R), f(T) and Ho?ava-Lifshitz Gravities

In this work, we have considered dilaton dark energy model in Weyl-scaled induced gravitational theory in presence of barotropic fluid. It is to be noted that the dilaton field behaves as a quintessence. Here we have discussed the role of dilaton dark energy in modified gravity theories, namely f(R),f(T) and Hořava-Lifshitz gravities and analyzed the behavior of the dilaton field and the corresponding potential in respect to these modified gravity theories instead of Einstein’s gravity. In f(R) and f(T) gravities, we have considered some particular forms of f(R) and f(T) and we have shown that the potentials always increase with the dilaton fields. But in Hořava-Lifshitz gravity, it has been seen that the potential always decreases as dilation field increases.     

Thermolysis of N‐Aryl Enaminoimine Hydrochloride Derivatives: A Short and General Method for the Synthesis of Pyranoquinolin‐3‐one and Pyranoacridin‐3‐one Derivatives

A short synthesis of 3H‐pyrano[3,2‐f]quinolin‐3‐one, 3H‐acenaphtho[1,2‐b]pyrano‐[3,2‐f]quinolin‐3‐one, and 3H‐benzo[h]pyrano[3,2‐a]acridin‐3‐one derivatives are described via thermolysis of suitable enaminoimine hydrochloride derivatives.     

On principle axis based line symmetry clustering techniques

In this paper, at first a new line symmetry (LS) based distance is proposed which calculates the amount of symmetry of a point with respect to the first principal axis of a data set. The proposed distance uses a recently developed point symmetry (PS) based distance in its computation. Kd-tree based nearest neighbor search is used to reduce the complexity of computing the closest symmetric point. Thereafter an evolutionary clustering technique is described that uses this new principal axis based LS distance for assignment of points to different clusters. The proposed GA with line symmetry distance based (GALS) clustering technique is able to detect any type of clusters, irrespective of their geometrical shape, size or convexity as long as they possess the characteristics of LS. GALS is compared with the existing genetic algorithm based K-means clustering technique, GAK-means, existing genetic algorithm with PS based clustering technique, GAPS, spectral clustering technique, and average linkage clustering technique. Five artificially generated data sets having different characteristics and seven real-life data sets are used to demonstrate the superiority of the proposed GALS clustering technique. In a part of experiment, utility of the proposed genetic LS distance based clustering technique is demonstrated for segmenting the satellite image of the part of the city of Kolkata. The proposed technique is able to distinguish different landcover types in the image. In the last part of the paper genetic algorithm is used to search for the suitable line of symmetry of each cluster.     

Electrochemical Sensor Based on Oxidation of 2,8‐Dihydroxyadenine to Monitor DNA Damage in Calf Thymus DNA

A novel and reliable direct electrochemical method has been established to monitor DNA damage in acid hydrolyzed calf thymus DNA, based on the determination of 2,8‐dihydroxyadenine (2,8‐DHA). A single‐wall carbon nanotubes (SWCNT) modified edge plane pyrolytic graphite electrode (EPPGE) has been used as a sensor to monitor the DNA damage. 2,8‐DHA the main in vivo adenine oxidation product undergoes oxidation at ～395 mV at SWCNT modified EPPGE using square wave voltammetry (SWV). The sensor exhibits potent and persistent electron‐mediating behavior. A well‐defined oxidation peak for the oxidation of 2,8‐DHA was observed at modified electrode with lowering of peak potential and increase in peak current as compared to bare EPPGE. At optimal experimental conditions, the catalytic oxidative peak current was responsive with the 2,8‐DHA concentrations ranging from 0.05 nM to 100 nM. The detection limit was 3.8×10^?11 M and limit of quantification was 1.27×10^?10 M. The modified electrode exhibited high stability and reproducibility.     

Interaction between zwitterionic and anionic surfactants: spontaneous formation of zwitanionic vesicles

The physicochemical properties, such as critical micelle concentration (cmc), surface tension at cmc (γ(cmc)), and surface activity parameters of the mixtures of a new amino acid-based zwitterionic surfactant, N-(n-dodecyl-2-aminoethanoyl)-glycine (C(12)Gly) and an anionic surfactant, sodium dodecyl sulfate (SDS) at different molar fractions, X(1) (= [C(12)Gly]/([C(12)Gly] + [SDS])) of C(12)Gly were studied. A synergistic interaction was observed between the surfactants in mixtures of different X(1). The self-organization of the mixtures at different molar fractions, concentrations, and pH was investigated. Fluorescence depolarization studies in combination with dynamic light scattering, and transmission electron microscopic and confocal fluorescence microscopic images suggested the formation of bilayer vesicles in dilute solutions of SDS rich mixtures with X(1) ≤ 0.17 in the pH range 7.0 to 9.0. However, the electronic micrographs showed structures with fingerprint-like texture in moderately dilute to concentrated C(12)Gly/SDS mixture at X(1) = 0.50. The vesicles were observed to transform into small micelles upon lowering the solution pH and upon increase of total surfactant concentration in mixtures with X(1) ≤ 0.17. However, decrease of SDS content transformed vesicles into wormlike micelles. The structural transitions were correlated with bulk viscosity of the binary mixtures.     

Effect of Nanoclay on the Morphology and Properties of Nylon 6 and Poly(Methyl Methacrylate) (PMMA) Blends

The effect of organomodified nanoclay on the morphology and properties of a (70/30 w/w) nylon 6/poly(methyl methacrylate) (PMMA) blend prepared by a melt processing method was investigated. The number average domain diameter (D_n ) of the dispersed PMMA phase was found to decrease with the addition of a small amount [0.5 per hundred resin (phr)] of clay in the blend. A much finer dispersion of the minor phase in the presence of a higher amount (5 phr) of clay indicated better mixing efficiency and improved morphology in the blend. X-ray diffraction indicated the exfoliation of the clays in the nylon 6 matrix, whereas PMMA chains only intercalated into the clay layers. However, the same effect of the clay was not observed in a (30/70 w/w) nylon 6/PMMA blend when nylon 6 became the dispersed domains. In the (30/70 w/w) nylon 6/PMMA blend, the addition of organomodified nanoclay (up to 2 phr) increased the D_n of the nylon 6 domains by preferential location of the clays inside the nylon 6 domains. Addition of styrene-maleic anhydride (SMA) copolymer effectively reduced the D_n of disperse phases in both compositions of the nylon 6/PMMA blends. Thus, in nylon 6/PMMA blends, clay platelets could prevent the coalescence of dispersed domains during melt mixing as long as it was dispersed in the matrix phase of the blend. Mechanical properties and thermal stability of the blends were also improved in the presence of clay.     

Simultaneous quantification of vasicine and vasicinone in different parts of Justicia adhatoda using high-performance thin-layer chromatography‒densitometry: comparison of different extraction techniques and solvent systems

JPC – Journal of Planar Chromatography – Modern TLC - The present study was carried out for screening an efficient extraction method and extracting solvent in different plant parts of...     

Tuning Proton Conductivity by Interstitial Guest Change in Size‐Adjustable Nanopores of a CuI‐MOF: A Potential Platform for Versatile Proton Carriers

By exploiting the breathing behavior of nanopores, we have studied for the first time the dependency of the guest‐induced proton conductivity of an interpenetrated Cu^I metal–organic framework (Cu^I‐MOF, [ 1 ]) on various guest molecules. Proton conductivities of over 10^?3 S cm^?1 under humid conditions were induced by a series of guest molecules, namely N,N‐dimethylformamide, dimethyl sulfoxide, diethylamine, 1,4‐dinitrobenzene, nitrobenzene, pyridine, and 1H‐1,2,4‐triazole. A detailed investigation of the guest‐incorporated complexes revealed that low‐energy proton conduction occurs under humid conditions through the Grotthuss mechanism in [ 1 ?NB] and through the vehicle mechanism in the rest of the complexes. Single‐point energy computations revealed considerable stabilization upon guest encapsulation. To the best of our knowledge, [ 1 ] represents the first example in which considerably high protonic conductivity is triggered upon the facile incorporation of small molecules of such a variety. The investigation portrayed herein may be a stepping stone towards the rational design of proton‐conducting materials for practical applications.     

Selective Sensing of Phosphates by a New Bis‐heteroleptic RuII Complex through Halogen Bonding: A Superior Sensor over Its Hydrogen‐Bonding Analogue

The selective phosphate‐sensing property of a bis‐heteroleptic Ru^II complex, 1 [PF₆]₂, which has a halogen‐bonding iodotriazole unit, is demonstrated and is shown to be superior to its hydrogen‐bonding analogue, 2 [PF₆]₂. Complex 1 [PF₆]₂, exploiting halogen‐bonding interactions, shows enhanced phosphate recognition in both acetonitrile and aqueous acetonitrile compared with its hydrogen‐bonding analogue, owing to considerable amplification of the Ru^II‐center‐based metal‐to‐ligand charge transfer (MLCT) emission response and luminescence lifetime. Detailed solution‐state studies reveal a higher association constant, lower limit of detection, and greater change in lifetime for complex 1 in the presence of phosphates compared with its hydrogen‐bonding analogue, complex 2 . The ¹H NMR titration study with H₂PO₄^? ascertains that the binding of H₂PO₄^? occurs exclusively through halogen‐bonding or hydrogen‐bonding interactions in complexes 1 [PF₆]₂ and 2 [PF₆]₂, respectively. Importantly, the single‐crystal X‐ray structure confirms the first ever report on metal‐assisted second‐sphere recognition of H₂PO₄^? and H₂P₂O₇^2? with 1 through a solitary C?I???anion halogen‐bonding interaction.