On the Reaction of 3-Acetyl Coumarin with Alkyl Phosphites. Structural Confirmations Based on X-Ray Crystallography

3-Acetyl coumarin ( 1 ) reacts with dialkyl phosphites at 100°;C for 8 h to give the phosphonates 2 . Under the same experimental conditions, 1 reacts with trialkyl phosphites to form a mixture of the phosphonates 2 and 3 . The molecular structures of these products were elucidated by x-ray crystallography.     

Swelling Characterization of the Superabsorbent Copolymer in the Petroleum-Based Solvent-Water Mixtures

The crosslinked and porous copolymer grains were synthesized by inverse suspension polymerization of acrylamide. The synthesized copolymer was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). It was achieved to absorbed 418 g water by 1 g copolymer after 5 min waiting time. Moreover, it was seen that about 99% of water was absorbed by 1 g copolymer in the solvent water mixtures (300 mL solvent–200 mL distilled water) after 2.5 min waiting time. The diffusion coefficients of the copolymer in the solvent-water mixtures were found between 8.87 · 10⁴ and 10.64 · 10⁴ cm²s^?1. Furthermore, the copolymer in distilled water achieved to reach a high value of the diffusion coefficient (13.2 · 10⁴ cm²s^?1).     

Protection of Copper Surface Against Corrosion by Cationic Surfactant in Seawater

The protection power of the cationic surfactant decylammonium acetate (DAA) in seawater has been studied to define the perfect conditions have to be found for using it as a corrosion inhibitor for copper surface. The adsorption isotherm of this surfactant on copper surface has been determined at different interval times at 30°C. The given isotherms have, in general, similar shapes exhibiting a Languimirian L-shape. The corrosion measurement has been determined according to weight loss method. The study declines that cationic DAA, in seawater, protects well the copper surface against corrosion when added with low concentrations, while high concentrations show bad inhibition efficiency. ICP spectroscopic analysis assures this result where high Cu% has been obtained in the presence of high DAA concentration.     

Effect of adenine on bacterial translocation using technetium-99m labeled E. coli in an intestinal obstruction model in rats

This study aims to investigate effects of adenine on bacterial translocation (BT) using ^99mTc-labeled E. coli in an intestinal obstruction rat model. In the study twenty-one rats were used. The rats were divided into three groups according to different feeding patterns. The control group (CG) was fed with a standard chow diet for 7 days. Group A1 and group A2 were fed with adenine supplemented chow diet for 7 days. At the end of the feeding period, after all groups was submitted intestinal obstruction. ^99mTc-E. coli was injected into the rats’ terminal ileum under anesthetic. The rats were sacrificed under aseptic conditions at 24th h after the surgery. The uptake of ^99mTc-E. coli was determined in organs such as the liver, mesenteric lymph nodes, spleen and ileum. Group A1 and group A2 results show that the uptake of ^99mTc-E. coli decreased in the blood and organs comparing to the CG. As a result, it was observed that adenine reduced the level of BT when compared with CG. The beneficial effect of adenine on BT in intestinal obstruction was observed. However, further studies are needed to more clearly assess how this benefit can be achieved.     

Retention profile of Fe,Mn and Cu onto chemically treated polyurethane with carbon disulfide

Dithiocarbamate modified polyurethane foam (DTC-PUF) was synthesized as a new solid-phase extraction sorbent for the preconcentration and determination of Fe(II), Mn(II) and Cu(II) in environmental samples using flame atomic absorption spectrometry. Maximum extraction of the elements was achieved at pH 5–7 and flow rate 3 mL min^?1. Quantitative desorption was achieved by 10 mL from 1.0 mol L^?1 HCl solution. The capacity of the sorbent was 149.2 ± 0.5, 237.5 ± 0.2, 200.2 ± 0.1 μg g^?1 and the limit of detection was of 0.015, 0.015 and 0.012 μg mL^?1for Fe(II), Mn(II) and Cu(II), respectively. A preconcentration factor of 100 was obtained for all elements. The developed method was successfully applied to the determination of the tested elements in water (tap and lake) and plant (spinach and parsley leaves) samples and showed good recovery values from 98 to 111% with corresponding RSD values ranged from 0.6 to 8.6%.     

Modeling of absorption kinetics of poly(acrylamide) hydrogels crosslinked by EGDMA and PEGDMAs

In this study, acrylamide-based hydrogels are synthesized by free radical solution polymerization in aqueous solution using ethylene glycol dimethacrylate (EGDMA) and its derivative polyethylene glycol dimethacrylate (PEGDMA) with different molecular weights as crosslinkers in the solution medium. The Fourier transform infrared spectroscopy technique is used for the structural characterization of the hydrogels. Dynamic swelling tests are conducted on acrylamide-based hydrogels for the determination of the swelling characteristics with respect to different crosslinking concentrations at room temperature. The parameters of swelling kinetics and diffusion mechanisms of the hydrogels are calculated with the aid of the data obtained. Accordingly, PEGDMA and EGDMA absorption capacity is found to increase with increasing concentrations. The lowest and highest water absorption capacities in PEGDMA₈₁₀ and EGDMA crosslinked hydrogels are 22.73–48.39 and 10.15–16.02 g/g, respectively. Water intake of hydrogels crosslinked by EGDMA and PEGDMAs followed Fickian nature type diffusion except for PEGDM₈₁₀, which has a swelling exponent greater than 0.5 and so does not follow a Fickian type of diffusion. PEGDM₈₁₀ showed the fastest diffusion rate of between 5.87 × 10^?4 and 10.87 × 10^?4 cm² s^?1.     

A one-pot tandem synthesis of various 1,2-disubstituted benzimidazoles

A facile method to synthesize various 1,2-disubstituted benzimidazoles is developed. It is suggested that formation of a Meisenheimer adduct between the substrate, amine, and solvent aids the N-arylation process. The generality of the protocol is demonstrated by the efficient reactions involving numerous substituents ranging from electron-withdrawing groups to electron-donating groups.     

Numerical Modeling of Functional Fatigue in NiTi Wires

Motivated by the high potential of shape memory alloys (SMA) in several industrial applications, we investigate the material response under cyclic loading. In particular, the focus is set on the modelling of functional fatigue, which results in the deterioration of the specific features of SMA. In fact, functional fatigue restricts SMA in terms of its applicability for real structures and workpieces. This necessitates the development of material models which take this phenomenon into account. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)