Characterization of poly(2-vinylpyridine)-block-poly(methyl methacrylate) copolymers and blends of their homopolymers by liquid chromatography at critical conditions

Poly(2-vinylpyridine)s (P2VPs) are important polymers with extensive applications in modern day material science. P2VP is an exceptional case for liquid chromatography because of certain polar interactions with most of the stationary phases. In the present study, we established the critical adsorption point (CAP) of P2VP for the first time. The effectiveness of the method is demonstrated by analyses of blends and block copolymers of P2VP and PMMA. The CAP of PMMA is established for determination of molar mass of P2VP component of above mentioned blends and block copolymers. The methods successfully demonstrate the separation of both types of homopolymers from the rest of the samples in conjunction with the determination of molar mass distribution of noncritical block or component. Graphical Abstract

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Classification of Plane Symmetric Static Space-Times According to Their Noether Symmetries

In this paper we give a classification of plane symmetric static space-times using symmetry method. For this purpose we consider the Lagrangian corresponding to the general plane symmetric static metric in the Noether symmetry equation. This provides a system of determining equations. Solutions of this system give us classification of the plane symmetric static space-times according to their Noether symmetries. During this classification we recover all the results listed in Feroze et al. (J. Math. Phys. 42:4947, 2001) and Bashir and Ehsan (Il Nuovo Cimento B 123:1, 2008).     

Multi-component synthesis of highly substituted imidazoles catalyzed by nanorod vanadatesulfuric acid

Nanorod vanadatesulfuric acid (VSA NRs), as a recyclable and eco-benign catalyst, was used for one-pot synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles using aldehydes, benzil, benzoin or 9,10-phenanthrenequinone and ammonium acetate or aniline under solvent-free conditions providing high to excellent yields. VSA is easily prepared by a simple reaction of chlorosulfonic acid and sodium metavanadate in high purity. As compared with the conventional procedures, the present protocol offers several advantages such as simplicity of procedure, short reaction time, high yields, easy workup, recoverability and reusability of the catalyst and simple purification of the products.     

Internal Anatomy of Common Carp (Cyprinus carpio) as Revealed by Magnetic Resonance Imaging

Slices of T2-weighted and fat-suppressed images were obtained on a clinical scanner with the field strength of 1 T to identify various tissues, internal organs and structural details of a cyprinid fish (Cyprinus carpio). Different parts of pharyngeal and gastro-intestinal organs, liver and spleen were well distinguished. Kidneys were traced and the position of heart and its appendants such as bulbus arteriosus, ventral aorta and branchial arteries were identified. The images were confirmed by the corresponding slices of frozen fish.     

Size-controlled synthesis of CuO–ZrO<Subscript>2</Subscript> nanoparticles prepared through reverse micelle method

In this research, CuO–ZrO₂ nanoparticles are synthesized using microreactors made of surfactant/water/cyclohexane microemulsions. The effect of different microemulsion variables on the particle size and its distribution, such as water-to-surfactant molar ratio (W ₀) and different surfactants are discussed. Three different surfactant types including cationic (CTAB), anionic (AOT), and nonionic (Brij56) are used. Also a different amount of water to surfactant in nano composite synthesis is used. The powders were characterized by DTA/TG, XRD, SEM, EDS, TEM and BET techniques and their physical properties are compared. The results show a decrease of particles size in presence of cationic surfactant. Narrow particles size distribution of the resultant CuO–ZrO₂ nanocomposite in presence of cationic surfactant, anionic and nonionic surfactant is compared. Also for AOT surfactant, by raising water to surfactant molar ratio the particles size is increased and the optimum ratio is H₂O: Surfactant = 0.32:0.055, respectively.     

Quantum carpets: efficiently probing fractional revivals in position-dependent mass systems

Position-dependent-mass systems are of great importance in many physical situations,such as the transport of charge carriers in semiconductors with non-uniform composition and in the theory of many-body interactions in condensed matter.Here we investigate,numerically and analytically,the phenomenon of fractional revivals in such systems,which is a generic characteristic manifested by the wave-packet evolution in bounded Hamiltonian systems.Identifying the fractional revivals using specific probe...     

In silico studies of novel scaffold of thiazolidin-4-one derivatives as anti-Toxoplasma gondii agents by 2D/3D-QSAR,molecular docking,and molecular dynamics simulations

Structural Chemistry - Toxoplasma gondii is an obligate intracellular protozoa that can infect a wide variety of warm-blooded animals and humans. It was claimed that novel anti-Toxoplasma gondii...