Quinone-amine polymers. XII. Synthesis and characterization of novel polymers from 2-phenylbenzoquinone and aliphatic diamines

In order to study the effect of the presence of phenyl groups in poly (amino-quinone) (PAQ) polymers, several novel poly(amino-2-phenylbenzoquinone) (PhPAQ) polymers have been prepared from 2-phenylbenzoquinone and aliphatic diamines, such as 1,6-diaminohexane, 1,8-diaminooctane, 1,12-diaminodod+++++, and 1,4-diaminocyclohexane. Prior to the polymerization, 2-phenylbenzoquinone was generated in situ from 2-phenylhydroquinone in the presence of calcium hypochlorite as the oxidizing agent in dichloromethane. All of the polymers synthesized have been characterized with respect to their corresponding model compounds. It was also found that unlike their analogous PAQ polymers, PhPAQ polymers were highly soluble in many common organic solvents because of the presence of phenyl groups in their polymer backbone. © 1994 John Wiley & Sons, Inc.     

Evidence for Λc+ in inclusive pp → (Λ0π+π+π−) + X and pp → (K−π+p) + X at √s = 53 and 62 GeV

A search for the charmed baryon, Λ_c⁺, has been carried out in inclusively, measured Λ⁰π^±π⁺π^? and K^?π^±p final states with longitudinal x > 0.75 in an experiment at the CERN intersecting storage rings. An effect with invariant mass near 2.3 GeV is observed in Λ⁰π⁺π⁺π^? with cross section times branching ratio Bσ = (2.8±1.0) μb; similar effect is observed in K^?π⁺p with Bσ = (2.3 ± 0.3) μb. The effect is seen only in the positive charge state, in agreement with an interpretation as Λ_c⁺. However, it is pointed out that in the same experiment, the non-charmed hyperon state Σ(1385)⁺ also has a cross section much larger than its corresponding negative charge state Σ(1385)^?.     

Thermal Entanglement in a Two-Qutrit Spin-1 Anisotropic Heisenberg Model

The negativity (N) as a measure of thermal entanglement (TE) is studied for a two-qutrit spin-1 anisotropic Heisenberg XXZ chain with Dzyaloshinskii-Moriya (DM)...     

Random crystal field effects for spin-3/2 Blume-Capel model

The effects of crystal field (Δ) which is randomly turned on with probability p or turned off with probability 1−p on the sites of the Bethe lattice are investigated to study the critical behavior of the spin-3/2 Blume-Capel model. The order-parameters are obtained in terms of the recursion relations and then the possible phase diagrams are calculated at finite temperatures for given system parameters p, Δ and coordination numbers z=3, 4, 5 and 6. It was found that the phase diagrams change drastically for given probability and randomness. The first-order phase transitions are only found for higher p values and the lines of which get shorter and eventually disappear as p decreases. The critical lines do not present any qualitative differences with z, but they are seen at higher temperatures for higher z.     

Λ0 polarization in proton-proton interactions at √s = 53 and 62 GeV

Λ⁰'s produced in the inclusive reaction pp → Λ° + X with √s = 53 and 62 GeV at the CERN Intersecting Storage Rings are observed to be polarized along the normal to the production plane. In the ranges of longitudinal and transverse momenta, 15–24 and 0.6-1.4 GeV/c, respectively, the mean polarization is found to be ?(0.357±0.055).     

Essential oil composition,antioxidant activity and phenolic content of endemic Teucrium alyssifolium Staph. (Lamiaceae)

The present study was designed to examine the chemical composition of the essential oil, in vitro antioxidant activity and total phenolic and flavonoid content of extracts from plant parts (leaf, flower and stem) of Teucrium alyssifolium. The principle components of the essential oil were trans-β-caryophyllene (16.87%), ar-curcumene (11.43%) and bisabolene (11.06%), representing 39.36% of the oil. The total phenolic contents ranged between 13.99 and 41.54 mg of GAE/g of extract. The concentrations of flavonoids varied from 16.82 to 49.52 mg of Ru/g of extract. Antioxidant activity was determined in vitro using DPPH reagent and expressed as concentration of each extract required to inhibit radical by 50% (IC₅₀) values that ranged from 13.52 to 132.55 μg/ml. Our results have indicated that water extract of T. alyssifolium (part leaf) with a total content of polyphenols (41.54 mg of GAE/g) and an IC₅₀ of 13.52 μg/ml is more antioxidant.     

A bio-imprinted urease biosensor: Improved thermal and operational stabilities

Despite the increasing number of applications of biosensors in many fields, the construction of a steady biosensor remains still challenging. The high stability of molecularly bio-imprinted enzymes for its substrate can make them ideal alternatives as recognition elements for sensors. Urease (urea aminohydrolase, EC 3.5.1.5), which catalysis the hydrolysis of urea to ammonia and carbon dioxide, has been used in immobilized form in artificial kidney for blood detoxification. According to one report approximately half a million patients worldwide are being supported by haemodialysis. In this study, the enzyme of urease was first complexed by using a substrate analogue, thiourea, in aqueous medium and then this enzyme was immobilized on gelatin by crosslinking with glutaraldehyde on a glass electrode surface. Similarly, urease noncomplexed with thiourea was also immobilized on a glass electrode in the same conditions. The aim of the study was to compare the two biosensors in terms of their repeatability, pH stability and thermal stability, and also, linear ranges of two biosensors were compared with each other.