Maleimide polymers. I. A polymeric color reaction

Certain copolymers of maleimide and N-substituted maleimides yield brilliant colors when treated with sufficiently strong basic reagents under nonhydrolytic conditions. For color generation, the copolymer must be capable of HX elimination. The chromophores which account for color probably result from the ionization of acidic protons in structures involving one or more double bonds conjugated with imide carbonyl. The analogy to the color reactions of aconitylanil is pointed out. Spectra covering the range of 330–700 mμ are presented for a number of copolymer–amine color-generating systems. The colors produced in base with radical-initiated polymaleimide and imidazole-initiated poly-N-alkylmaleimides as well as the absence of color with anionic polymaleimide and radical poly-N-alkylmaleimides are discussed in light of what is known about their polymerization kinetics and mechanisms. Corresponding maleic anhydride copolymer systems are mentioned.     

Real time out-of-plane vibration measurement/monitoring using Talbot interferometry

In the present paper, application of Talbot interferometry for real-time vibration measurement is investigated. Experiments were conducted to measure/monitor out-of-plane motion of a vibrating loudspeaker membrane. Experimental results demonstrate that by using Talbot interferometry out-of-plane vibrations as well as phase lag between driving force and membrane oscillation can be measured.     

Electrocatalytic one pot synthesis of medicinally relevant 4H-benzo[g]chromene and pyrano[2,3-g]chromene scaffold via multicomponent-domino approach

A highly efficient one pot, multicomponent synthesis of 4H-benzo[g]chromene and pyrano[2,3-g]chromene derivatives are reported by electrochemically stimulated condensation of an aromatic aldehyde, malononitrile and some enolizable acidic compounds in ethanol at room temperature under constant current density. By utilizing common electrode materials and a simple constant current protocol, this method is a new alternative to conventional methods.     

Transient shear flow behavior of polymeric fluids according to the Leonov model

Summary The viscoelastic behavior of polymeric systems based upon the Leonov model has been examined for (i) stress growth and relaxation with intermittent shear flow, (ii) stress relaxation after a step in the shear strain and (iii) elastic recovery after shear flow. A large number of modes have been conveniently incorporated through the determination of the model parameters from conventional rheological data by using an effective least-square procedure. With a sufficient number of modes, the predictions are in very good agreement with corresponding experiments in literature, including the recent data for cases (i) and (ii) obtained by optical methods.The present theory agrees also with the Lodge-Meissner relation ( ₁₁ – ₂₂)/ ₁₂ = ₀ in a step-shear experiment. In general, the Leonov model leads to results which, in these test cases, are comparable to those from Wagner's theory. It is, however, considerably less difficult to apply, thus offering the possibility of analysing flow problems of practical interest.With 16 figures and 1 table     

Generalised BRST symmetry and gaugeon formalism for perturbative quantum gravity: Novel observation

In this paper the novel features of Yokoyama gaugeon formalism are stressed out for the theory of perturbative quantum gravity in the Einstein curved spacetime. The quantum gauge transformations for the theory of perturbative gravity are demonstrated in the framework of gaugeon formalism. These quantum gauge transformations lead to renormalised gauge parameter. Further, we analyse the BRST symmetric gaugeon formalism which embeds more acceptable Kugo–Ojima subsidiary condition. Further, the BRST symmetry is made finite and field-dependent. Remarkably, the Jacobian of path integral under finite and field-dependent BRST symmetry amounts to the exact gaugeon action in the effective theory of perturbative quantum gravity.     

GC�CMS Coupled with Hollow-Fiber Drop-to-Drop Solvent Microextraction for Determination of Antidepressants Drugs in Human Blood Sample

A simple, rapid and sensitive hollow-fiber with drop-to-drop solvent microextraction (HF-DDSME) combined with gas chromatography?Cmass spectrometry (GC?CMS) has been successfully developed for extraction and determination of antidepressants drugs (AD) in blood sample. The parameters that affect the separation and preconcentration of AD from sample solution were investigated. Calibration curve obtained for three AD were in the range of 100?C1,000; 150?C1,200; and 80?C1,200 ng mL^?1 for amitriptyline, imipramine, and promethazine, respectively, with correlation coefficient (R ² ) between 0.990 and 0.997. The limit of detection (LOD) obtained for amitriptyline, imipramine and promethazine was 25, 30 and 18 ng mL^?1, respectively. The developed method has been successfully applied for the determination of AD concentration in blood sample, and the recoveries for the spiked samples were in the range of 92.3?C97.6%. The sample preparation procedure is very simple, effective and virtually solvent-free, and indicated to be a good alternative for the traditional liquid?Cliquid extraction. Finally, the proposed method was successfully applied for the determination of drug concentration of AD in human blood sample.