Designing of layered double hydroxide,metal oxides,and borate-reinforced thermoplastic polyurethanes composites

Thermoplastic polyurethanes (TPUs) are widely used in automotive, medical, and marine applications due to their excellent properties such as high tensile strength, flexibility, and durability. However, the presence of isocyanate groups in TPUs increases their flammability and produces toxic gases during combustion, limiting their application. Here, the study aims to modify TPUs to improve their flame-retardant behavior. Various fillers such as metal oxides, Layer double hydroxides (LDH), and borates were synthesized and added into the TPU matrix by using extrusion and compression molding. At a 10% loading of Zinc-Magnesium oxides, a limiting oxygen index (LOI) of 25% was achieved, along with no dripping and complete burning cessation within 20 s. Magnesium aluminium LDH exhibited maximum flame retardancy at a 5% loading, with an LOI of 25%, burning cessation within 23 s without dripping, and a V1 rating. Overall, this research aims to develop TPU composites with improved fire safety properties by incorporating various additives. The synthesized additives showed potential for enhancing the mechanical, thermal, and flame-retardant properties of TPU.     

Combining ligand- and structure-based in silico methods for the identification of natural product-based inhibitors of Akt1

Molecular Diversity - The traditional method of drug discovery process has been surpassed by a rational approach where computer-aided drug designing plays a vital role in the identification of...     

Synthesis and biological evaluation of 1,2,4-triazolidine-3-thiones as potent acetylcholinesterase inhibitors: in vitro and in silico analysis through kinetics,chemoinformatics and computational approaches

Molecular Diversity - We have designed and synthesized a novel acidic ionic liquid and explored its catalytic efficiency for the synthesis of 1,2,4-triazolidine-3-thione derivatives. A simple...     

Erratum: “Martini Coarse-Grained Model for Polyethylenimine” [J. Comput. Chem. 2019, 40, 607–618, DOI:10.1002/jcc.25747]

Correction of calculation errors in the original article led to the change of bead type for the unprotonated beads in the coarse-grained polyethylenimine model. The original model was still of good quality while the updated model showed better performance in describing the interaction between polyethylenimine and DNA.     

Highly anisotropic elasticity of a dendrimeric liquid crystal

Magnetic and electrical Freedericksz measurements were performed on the second generation monodendritic liquid crystal G₂(OH). The deduced elastic constants were found to be exceptionally anisotropic: the splay elastic constant K₁₁ is more than an order of magnitude larger than the bend elastic constant K₃₃, and the twist constant K₂₂ is approximately twice K₃₃. The results are discussed in terms of molecular conformations. Received: 23 February 1998 / Revised and Accepted: 26 May 1998     

Di(2-ethylhexyl)sulfoxide as an extractant for plutonium(IV) from nitric acid medium

The liquid-liquid extraction behavior of plutonium(IV) from aqueous nitric acid media into n-dodecane by di(2-ethylhexyl)sulfoxide (DEHSO) was investigated over a wide range of conditions. Optimum-parameters such as the aqueous phase acidity, reagent and metal concentrations, etc., were established for efficient extraction-separation of tracer as well as macro levels of plutonium. It was found that the extraction increased with increasing nitric acid concentration up to 6M HNO₃ and then decreased. Extraction also increased with increasing extractant concentration. After loading of the organic phase with 2 to 50 mg/ml of U(VI), extractability of Pu(IV) became considerably lower. Recovery of Pu(IV) from the organic phase was accomplished using dilute uranium(IV) nitrate as the strippant.     

PHYCOERYTHROCYANINS FROM Westiellopsis prolifica AND Nostoc rivulare: CHARACTERIZATION OF THE PHYCOVIOLOBILIN CHROMOPHORE IN BOTH STATES*

Abstract— Phycoerythrocyanin or fractions enriched in it have been isolated from the filamentous cyanobacteria, Westiellopsis prolifica ARM 365 and Nostoc rivulare ARM 212. Both show the photoreversible photochromism (difference maxima at 503 and 570 nm) characteristic of this pigment, which is related to the phycoviolobilin chromophore on the α-subunit. Native phycoerythrocyanin and its β-subunit show little if any reversible photochemistry in the 600–620 nm region, where the phycocyanobilin chromophores absorb maximally. Instead the phycocyanobilin chromophores are bleached irreversibly. At the same time, the data show that reversible photochemistry is a useful analytical tool to detect phycoerythrocyanin in cyanobacterial extracts. Fluorescence measurements indicate that: (i) the 510 nm absorbing isomer of the violobilin chromophore has only little fluorescence; and (ii) the energy transfer from the violobilin chromophores to the cyanin chromophores is efficient only in the 570 nm form.     

Generalization of some duality theorems in nonlinear programming

Pseudoconvexity of a function on one set with respect to some other set is defined and duality theorems are proved for nonlinear programming problems by assuming a certain kind of convexity property for a particular linear combination of functions involved in the problem rather than assuming the convexity property for the individual functions as is usually done. This approach generalizes some of the well-known duality theorems and gives some additional strict converse duality theorems which are not comparable with the earlier duality results of this type. Further it is shown that the duality theory for nonlinear fractional programming problems follows as a particular case of the results established here.     

(75)As NMR study of antiferromagnetic fluctuations in Ba(Fe(1-x)Ru(x))(2)As(2)

The evolution of (75)As NMR parameters with composition and temperature was probed in the Ba(Fe(1-x)Ru(x))(2)As(2) system where Fe is replaced by isovalent Ru. While the Ru end member was found to be a conventional Fermi liquid, the composition (x = 0.5) corresponding to the highest T(c) (20 K) in this system shows an upturn in the (75)As [Formula: see text] below about 80 K, evidencing the presence of antiferromagnetic (AFM) fluctuations. These results are similar to those obtained in another system with isovalent substitution, BaFe(2)(As(1-x)P(x))(2) (Nakai et al 2010 Phys. Rev. Lett. 105 107003) and point to a possible role of AFM fluctuations in driving superconductivity.     

Synthesis of tetrahydropyrimidino[4,3‐a]isoquinolines via regiospecific N‐alkylation‐annulation of 4‐aryldihydropyrimidinones

4‐Aryldihydropyrimidinones were obtained in excellent yields via solid‐phase Biginelli reaction of arylaldehydes, β‐ketoester and urea, using bismuth nitrate, immobilized on Al₂O₃ as catalyst. Subsequently, the products were converted into corresponding tetrahydropyrimidino[4,3‐a]isoquinolines (69–73% yield) by one‐pot regiospecific N‐alkylation‐annulation reaction using sodium hydride and dimethylaminopyridine. J. Heterocyclic Chem., (2011).