C–H bond addition and copolymerization reactions of N-arylmaleimides: Fundamentals of coagent-assisted polymer cross-linking

Solid-state rheometry and model compound reactions are used to investigate free radical reactions of N-arylmaleimide coagents with saturated and unsaturated polymers. N,N′-m-phenylene dimaleimide (BMI) is shown to provide superior cross-link densities over diacrylate and diallyl coagents for all of the polymers studied, including linear low density polyethylene (LLDPE), poly(ethylene oxide) (PEO), cis-poly(butadiene) (PBD) and cis-poly(isoprene) (PIP). Studies of the N-phenylmaleimide (NPM) + cis-cyclooctane system show that C–H bond addition to yield N-aryl-2-alkylsuccimide grafts is the predominant reaction pathway, as opposed to maleimide homopolymerization. In contrast, peroxide-initiated reactions of cis-cyclooctene with small NPM concentrations generate highly alternating poly(cycloctene-alt-N-phenylmaleimide) in high yield, indicating that unsaturated mers in materials such as PBD engage maleimides in an efficient alternating copolymerization between electron-rich and electron-deficient monomer pairs. Factors that affect the reactivity of different polymers in these C–H bond additions and alternating copolymerizations are discussed.     

Evaporative light scattering detection based HPLC method for the determination of polysorbate 80 in therapeutic protein formulations

An evaporative light scattering detection (ELSD) based high-performance liquid chromatography (HPLC) method is developed for the determination of polysorbate 80 (tween 80) in therapeutic protein formulations. The method is simple and overcomes the difficulties associated with specificity and sensitivity. The method is suitable for the quantitation of polysorbate 80 in the usual formulation range (0.01-0.1%) as well as in trace amounts ≥13 μg/mL. The analysis is based on the removal of protein first by solid-phase extraction using Oasis HLB cartridges followed by HPLC analysis using Inertsil ODS-3 C 18 column (4.6×150 mm, 5 μm) using reversed-phase conditions. The detector response changes exponentially with an increase in polysorbate concentration. A very good linear fit of log ELSD response against log polysorbate 80 concentration is observed. The specificity, sensitivity, precision, and accuracy of the method are suitable for the quantitation of polysorbate 80 in protein formulations.     

The translation planes admitting a nonsolvable doubly transitive line-sized orbit

The finite translation planes of ordern not in {3⁴,3⁶,11²,19²,29²,59² that admit a non-solvable doubly transitive line-sized orbit are completely classified.     

On the equivalence of measures on loop space

Let K be a simply-connected compact Lie Group equipped with an Ad _K -invariant inner product on the Lie Algebra ?, of K. Given this data, there is a well known left invariant “H ¹-Riemannian structure” on L(K) (the infinite dimensional group of continuous based loops in K), as well as a heat kernel ν_T(k ₀, ·) associated with the Laplace-Beltrami operator on L(K). Here T > 0, k ₀∈L(K), and ν _T (k ₀, ·) is a certain probability measure on L(K). In this paper we show that ν₁(e,·) is equivalent to Pinned Wiener Measure on K on ? _s0 ≡<x _t : t∈ [0, s ₀]> (the σ-algebra generated by truncated loops up to “time”s ₀). Recevied: 9 September 1999 / Revised version: 13 March 2000 / Published online: 22 November 2000     

Cryogen-free dilution refrigerator for bolometric search of neutrinoless double beta decay (0νβ β) in 124Sn

The feasibility study for searching neutrinoless double beta decay in ¹²⁴Sn using cryogenic bolometer has been initiated. For this purpose, a custom-built cryogen-free dilution refrigerator, having a large cooling power of 1.4 mW at 120 mK, has been installed at TIFR, India. This paper describes the design, installation and performance of a cryogen-free dilution refrigerator (CFDR-1200). The performance of CFDR-1200 has been analysed using Takano’s model developed for conventional (wet) dilution refrigerators.     

Multicomponent One-pot Diastereoselective Synthesis ofBiologically Important Scaffold under Microwaves

A simple and fast three-component diastereoselective synthesis of biologically important spiro scaffold 4 wascarried out in reasonable purity starting from readily available 1H-indole-2,3-dione 1,ethyl cyanoacetate 2 and4-hydroxycoumarin 3 under microwave in high yield(88%-92%)and short time.     

Highly diastereoselective synthesis of new chromenylaminoanthraquinones through a one-pot, three-component hetero Diels–Alder reaction

A new, efficient, and diastereoselective one-pot synthesis of cis-fused pyrano and furano chromenylaminoanthraquinones through hetero Diels–Alder reaction of 1-aminoanthraquinone and salicylaldehydes with electron-rich alkenes such as 3,4-dihydro-2H-pyran, 2,3-dihydrofuran, and ethyl vinyl ether under mild conditions is reported.