Development of an Efficient Procedure for Determination of Copper,Zinc and Iron after Solid Phase Extraction on 3‐(1‐(1‐H‐Indol‐3‐yl)‐3‐Phenylallyl)‐1H‐Indole Loaded on Duolite XAD 761

A method for the simultaneous preconcentration of Cu²⁺,Zn²⁺ and Fe³⁺ ions, in some food samples has been reported. The method is based on the adsorption of 3‐(1‐(1‐H‐indol‐3‐yl)‐3‐phenylallyl)‐1H‐indole (IPAI) loaded on Duolite XAD 761. The metal ions adsorbed on the modified solid phase resin are eluted using 6 mL of 4 mol L^?1 nitric acid. The influences of the analytical parameters including pH and amount of ligand and solid phase and type and amount of surfactant and sample volume on the metal ions recoveries were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally higher than 95% with a RSD lower than 5%. The method has been successfully applied for these metals content evaluation in some real samples.     

Sonochemical synthetic methods to produce functionalized conducting copolymers

Polyaniline (PANI) is one of the most investigated intrinsically conducting polymers. Copolymerization of aniline with aniline derivatives was considered one of the most effective and promising ways of improving the properties of PANI. In this work, firstly ethyl 3‐aminobenzoate and butyl 3‐aminobenzoate were synthesized from 3‐aminobenzoic acid by direct esterification. Then the copolymerization of 3‐amino benzoic acid, ethyl 3‐aminobenzoate, and butyl 3‐aminobenzoate with aniline was carried out by sonochemical polymerization in aqueous hydrochloric acid using ammonium persulfate (APS) as an initiator. The effects of variation in the molar ratio of the two monomers on chain structure, conductivity, and the redox properties of the copolymer are discussed. The prepared polymers are characterized by ¹H NMR spectroscopy, X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT‐IR). Thermal behavior of the prepared copolymers was studied by differential scanning calorimetry. The copolymers were doped with HCl and their conductivity was measured. Copyright © 2009 John Wiley & Sons, Ltd.     

Kalman filtering for reliable estimation of BBB permeability

INTRODUCTION: The blood-brain barrier (BBB) plays an important role in the pathophysiology of a number of central nervous system disorders. In the past, a number of laboratory techniques have been proposed to quantify permeability coefficient ki, an important index of barrier function. Recently, magnetic resonance imaging (MRI) has been used to estimate ki based on graphical plot technique. The MR technique was found to be in good agreement with the gold standard, quantitative autoradiography (QAR). However, a reduced image signal-to-noise ratio, among other factors such as partial volume effects, did not allow reliable estimation of permeability coefficients. This proof-of-principle study proposes the use of Kalman filter as a filtering technique for a reliable estimation of permeability coefficients. The results are compared to those obtained using the Wiener filter technique. MATERIALS AND METHODS: MRI experiments were performed in Wistar rats (N=2) using a 4.7-T Bruker Biospec MR system (Bruker Biospin, Billerica, MA). After acquiring localizer images, T2-weighted diffusion-weighted imaging images were acquired. Finally, a rapid T1 mapping protocol was implemented to acquire one pre-gadolinium diethylenetriamine pentaacetic acid baseline data set followed by postinjection data sets at 3-min intervals for 45 min. Data were postprocessed with and without the application of Kalman and Wiener filters to obtain an estimate of ki. RESULTS AND DISCUSSION: Comparing T1 maps, Patlak plots and permeability maps with and without the Kalman filtering presented several interesting observations. Kalman-filtered Patlak plots, compared to nonfiltered plots, showed that discrete data points on the plot were closer to the line fit. The number of time points used for the construction of the graphical plot had no effect on permeability coefficient estimates when the Kalman filter was used. A box-and-whiskers plot showed longer Y-error bars for nonfiltered and Wiener data compared to Kalman-filtered data. These observations suggest that it may be possible to obtain reliable permeability coefficient estimates in a short study time by applying the Kalman filter to the data. Future work involves investigating the application of this filter on a large-sample-size animal study and evaluating the role of partial volume effects on BBB permeability estimation.     

Rings consisting entirely of certain elements

We completely determine when a ring consists entirely of weak idempotents, units and nilpotents. We prove that such ring is exactly isomorphic to one of the following: a Boolean ring; Z₃ ⊕ Z₃; Z₃ ⊕ B where B is a Boolean ring; local ring with nil Jacobson radical; M₂(Z₂) or M₂(Z₃); or the ring of a Morita context with zero pairings where the underlying rings are Z₂ or Z₃.     

A tandem Aldol-Diels-Alder reaction accelerated in water: An approach to the Catalyst-Free One-Pot synthesis of spiro Thio-Oxindoles

Spiro thio-oxindoles are prepared in situ by the reaction of the corresponding aldehydes and thio-oxindoles in a straightforward, environmentally friendly, highly efficient and simple procedure. The reaction took place in water with no catalyst added. This one-pot reaction afforded regio- and diastereoselective products in high yields (61–93%).     

One-pot, three-component condensation of 2-hydroxybenzaldehyde derivatives, primary amines with alkyl isocyanides to N-alkyl-2-(2-hydroxyphenyl)-2-imino-acetamides

One-pot, three-component condensation of 2-hydroxybenzaldehyde derivatives, primary amines with alkyl isocyanides is reported. N-alkyl-2-(2-hydroxyphenyl)-2-iminoacetamide derivatives are generated presumably via the preliminary formation of N, N′-disubstituted benzo[b]furan-2,3-diamines and subsequent oxidation with molecular oxygen.      

A facile synthesis of chromeno[3,4-c]spiropyrrolidine-oxindoles via 1,3-dipolar cycloadditions

A facile one-pot synthesis of chromene bearing novel spiropyrrolidine-oxindoles has been accomplished by the [3+‏2]-cycloaddition reaction of 3-acetyl-2H-chromen-2-ones with azomethine ylides derived in situ from isatin or N-methyl isatin with sarcosine.     

One-pot synthesis of 1,2-disubstituted pyrrolo[2,3-b]quinoxalines via palladium-catalyzed heteroannulation in water

The reaction of N-alkyl-3-chloroquinoxaline-2-amines with 1-alkynes, catalyzed by Pd-Cu, in the presence of sodium lauryl sulfate as the surfactant in water, leads to the one-pot formation of 1,2-disubstituted pyrrolo[2,3-b]quinoxalines in good-to-high yields.     

Zero divisors and units with small supports in group algebras of torsion-free groups

Kaplansky’s zero divisor conjecture (unit conjecture, respectively) states that for a torsion-free group G and a field 𝔽, the group ring 𝔽[G] has no zero divisors (has no units with supports of size greater than 1). In this paper, we study possible zero divisors and units in 𝔽[G] whose supports have size 3. For any field 𝔽 and all torsion-free groups G, we prove that if αβ = 0 for some non-zero α,β∈𝔽[G] such that |supp(α)| = 3, then |supp(β)|≥10. If 𝔽 = 𝔽₂ is the field with 2 elements, the latter result can be improved so that |supp(β)|≥20. This improves a result in Schweitzer [J. Group Theory, 16 (2013), no. 5, 667–693]. Concerning the unit conjecture, we prove that if αβ = 1 for some α,β∈𝔽[G] such that |supp(α)| = 3, then |supp(β)|≥9. The latter improves a part of a result in Dykema et al. [Exp. Math., 24 (2015), 326–338] to arbitrary fields.