Electrochemical performance of multi-walled carbon nanotube composite electrodes is enhanced with larger diameters and reduced specific surface area

Multi-walled carbon nanotubes (MWCNT) have been widely used to fabricate composite electrodes due to their electrochemical properties. MWCNTs can be fabricated by various approaches and a range of MWCNT types and sizes has been developed. This study focuses on understanding the influence MWCNT diameter and specific surface area has on the electrochemical properties of a composite electrode. MWCNTs with fixed length range and diameters ranging from 10–20 to 50–80 nm were examined in this study. The amount of MWCNT utilised to fabricate the electrodes was identical and above the percolation threshold. MWCNT electrodes fabricated with larger diameters showed enhanced thermodynamic and kinetic properties towards common redox species which covered surface-insensitive, surface-sensitive and adsorption-based processes. Overall, these findings indicate that the number of strands of MWCNT alone is not essential for enhanced conductivity in composite materials but other geometric parameters play important roles.     

Effects of polarization force and nonthermal ions on dust-acoustic (DA) shock waves in a strongly coupled dusty plasma with positively charged dust

The nonlinear propagation of the dust-acoustic (DA) waves in a strongly coupled dusty plasma containing Maxwellian electrons, nonthermal ions, and positively charged dust is theoritically investigated by a Burgers equation. The effects of the polarization force (which arises due to the interaction between electrons and highly positively charged dust grains) and nonthermal ions are studied. DA shock waves are found to exist with positive potential only. It represents that the strong correlation among the charged dust grains is a source of dissipation, and is responsible for the formation of DA shock waves. The effects of polarization force and nonthermal ions significantly modified the basic features of DA shock waves in strongly coupled dusty plasma.     

Synthesis and Pharmacological Use of 10H-Phenothiazines,Their Sulfones,and Ribofuranosides

This article describes the synthesis of 10H-phenothiazines from 2-aminobenzenethiol and o-halonitrobenzenes via Smiles rearrangement. Upon refluxing with hydrogen peroxide in glacial acetic acid, these phenothiazines yield the corresponding 10H-phenothiazine-5,5-dioxides. The phenothiazines have also been used as base to prepare ribofuranosides by the reaction with β-D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antioxidant and antimicrobial activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Canine Parvovirus Type 2a (CPV-2a)-Induced Apoptosis in MDCK Involves Both Extrinsic and Intrinsic Pathways

The canine parvovirus type 2 (CPV-2) causes an acute disease in dogs. It has been found to induce cell cycle arrest and DNA damage leading to cellular lysis. In this paper, we evaluated the apoptotic potential of the “new CPV-2a” in MDCK cells and elucidated the mechanism of the induction of apoptosis. The exposure of MDCK cells to the virus was found to trigger apoptotic response. Apoptosis was confirmed by phosphatidylserine translocation, DNA fragmentation assays, and cell cycle analysis. Activation of caspases-3, -8, -9, and -12 and decrease in mitochondrial potential in CPV-2a-infected MDCK cells suggested that the CPV-2a-induced apoptosis is caspase dependent involving extrinsic, intrinsic, and endoplasmic reticulum pathways. Increase in p53 and Bax/Bcl2 ratio was also observed in CPV-2a-infected cells.     

Sound velocity in binary liquid mixtures and the statistical mechanical theories

Sound velocity in three binary liquid mixtures benzene+cyclohexane (I), cyclohexane+carbontetrachloride (II) and benzene+carbontetrachloride (III) has been measured. Significant structure and Flory — Patterson theories have been employed to evaluate ultrasonic velocity in the systems. The values are in good agreement with the experimental ones. A comparative study of significant structure theory and Flory-Patterson Theory has been made. Both the theories give satisfactory results for the three liquid mixtures.     

Cofilin-Membrane Interactions: Electrostatic Effects in Phosphoinositide Lipid Binding

The actin cytoskeleton interacts with the cell membrane primarily through the indirect interactions of actin-binding proteins such as cofilin-1. The molecular mechanisms underlying the specific interactions of cofilin-1 with membrane lipids are still unclear. Here, we performed coarse-grain molecular dynamics simulations of cofilin-1 with complex lipid bilayers to analyze the specificity of protein-lipid interactions. We observed the maximal interactions with phosphoinositide (PIP) lipids, especially PIP₂ and PIP₃ lipids. A good match was observed between the residues predicted to interact and previous experimental studies. The clustering of PIP lipids around the membrane bound protein leads to an overall lipid demixing and gives rise to persistent membrane curvature. Further, through a series of control simulations, we observe that both electrostatics and geometry are critical for specificity of lipid binding. Our current study is a step towards understanding the physico-chemical basis of cofilin-PIP lipid interactions.     

Synthesis of chiral organocatalysts derived from aziridines: application in asymmetric aldol reaction

We report the synthesis of a new series of highly efficient chiral organocatalysts derived via the regio- and stereoselective ring opening of chiral aziridines with azide anions. The catalysts have proved to be very efficient for a direct asymmetric aldol reaction, both with cyclic as well as acyclic ketones in brine with 2 mol % of catalyst loading, and afforded the products in excellent yields (up to 99%) and enantioselectivities (up to >99%). The chiral aldol adduct obtained has further been converted to a chiral azetidine ring via a convenient pathway.     

Potentiometric sensor for the nanoscale monitoring of Ni2+ ion in environmental samples by the fabrication of coated pyrolytic graphite electrode based on a novel C–C-coupled compound

Novel ligand 5,5?-((3-nitrophenyl)methylene)bis(2,6-diaminopyrimidin-4(3H)-one) (L) was synthesised and characterised. Preliminary studies on L have showed that it has more affinity towards the Ni²⁺ ion. Thus, the L was used as the electroactive material in the fabrication of poly(vinyl chloride) (PVC)-based membrane sensors such as coated graphite electrode (CGE) and coated pyrolytic graphite electrode (CPGE). Several polymeric membranes were fabricated by incorporating L as ionophore, NaTPB as anion excluders and BA, 1-CN, DBP, DOP and o-NPOE as solvent mediators and their effect on potentiometric response studied. Comparative electroanalytical studies performed on the CGE and CPGE depict that the CPGE with optimised membrane composition of L:PVC:o-NPOE:NaTPB in the ratio of 7:33:58:2 (w/w, mg) exhibited the best response in terms of wide working concentration range from 2.0 × 10^?8 to 1.0 × 10^?1 mol L^?1, (3.64 µg L^?1 –18.2 g L^?1) lower detection limit of 8.1 × 10^–9 mol L^?1 (1.47 µg L^?1) with Nernstian compliance of 29.4 ± 0.2 mV decade^?1 of activity of Ni²⁺ ion in the pH range of 3.5–9.0. The sensor can work satisfactorily in water–acetonitrile and water–methanol mixtures. It can tolerate 30% acetonitrile and 20% methanol content in the mixtures. The sensor showed fast response time of 8 s and could be used successfully for a period of 4 months. The sensor reflects its utility in the quantification of Ni²⁺ ion in real samples and has been successfully employed as an indicator electrode in the potentiometric titration of Ni²⁺ ion with EDTA.     

Production of reactive oxygen species on photolysis of dilute aqueous quinone solutions

We have examined the generation of the reactive oxygen species (ROS) superoxide and hydrogen peroxide (H2O2) by irradiation of dilute aqueous solutions of disodium anthraquinone-2-6-disulfonate (AQDS) with simulated sunlight. Irradiating a solution of AQDS in 2 mM NaHCO3 and 0.01 M NaCl produced superoxide and H2O2 at nanomolar concentrations. Experiments in which initial concentrations of dioxygen, H2O2, the superoxide radical trap nitroblue tetrazolium and the electron donor dimethyl sulfoxide were varied suggested that the interaction of solvent water with photo-excited quinone moieties produces dioxygen-reducing radicals, and that these are the primary source of ROS in the system. A kinetic model for ROS production is proposed based on our experimental data.     

Advancement in synthetic strategies of bisdimedones: Two decades study

Bisdimedones have emerged as an important and versatile moiety in the field of synthetic and medicinal chemistry. It is screened as a precursor for the synthesis of several heterocycles such as acridinediones, xanthenediones, thioxanthenes, and benzopyrans that exhibited immense pharmacological as well as industrial applications. Its extensive characteristics have attracted the scientists to develop various protocols for the synthesis of bisdimedones and their derivatives from the reaction of dimedone with several aldehydes under different environmental conditions using various types of catalysts. This review encapsulates the recent progress in the synthesis of bisdimedone derivatives under several reaction protocols such as the use of nanoparticles, ionic liquids, metal salts, simple organic compounds, and catalyst-free conditions, and so forth in the last 20 years.