Li‐doped nanosized TiO2 powder with enhanced photocalatylic acivity under sunlight irradiation

This work reports on the synthesis of Li‐doped TiO₂ nanoparticles using the sol–gel process and solid‐state sintering, and investigates their potential use as a photocatalyst for degradation under sunlight excitation of different organic model compounds in aqueous solution. The structure of the nanocrystals was examined by X‐ray diffraction, UV‐vis ground state diffuse reflectance absorption spectra and X‐ray photoelectron emission spectroscopy. Results showed that samples prepared by sol–gel process and calcined at 400 °C are composed of a mixture of anatase and rutile phases, in contrast to the one prepared by solid‐state sintering, which exhibits an anatase phase with Li being involved in a spinel phase. The photocatalytic degradation of aqueous solutions of different aromatic compounds was successfully achieved under sunlight excitation in presence of Li‐doped TiO₂ prepared via sol–gel process. It was shown that the calcination temperature and the preparation mode greatly affect the photocatalytic efficiency. Copyright © 2010 John Wiley & Sons, Ltd.     

GC Comparative Analysis of Leaf Essential Oils from Two Myrtle Varieties at Different Phenological Stages

The essential oils obtained from leaves of two Myrtus communis varieties (baetica and italica), growing wild in North Tunisia, were investigated by GC and GC–MS at their different phenological stages. The highest essential oil yield was observed at the flowering stage with 0.6% (w/w) for italica and 0.4% (w/w) for baetica and 49 compounds were identified. The main essential oil leaf compounds of both myrtle varieties, belonging to the monoterpene class, were α-pinene, 1,8-cineole, limonene and linalool and their percentages showed significant changes during the phenological stages.

     

On the Number of Restricted Prime Factors of an Integer

Let \({q\geqq2}\) be an integer and denote S(n) the sum of the digits in base q of the positive integer n. Our main result is to estimate the sum \({\Sigma_{n\leqq x}\tilde{\omega}(n)}\) where \({\tilde{\omega}(n)}\) is the number of distinct prime factors p of n such that \({S(p) \equiv a \,{\rm mod} \,b \,(a \in \mathbb{Z}, b\geqq 2)}\) .     

Ladder-type P,S-bridged trans-stilbenes

Phosphole-containing π-systems have emerged as building blocks with enormous potential as electronic materials because of the tunability of the phosphorus center. Among these, asymmetric P-bridged trans-stilbenes are still rare, and here an elegant and efficient synthesis toward such fluorescent molecular frameworks is described. Fine-tuning of the photophysical properties is attempted by enforcing the planarization of the phosphorus tripod and thus increasing the interaction between the phosphorus lone pair and the π-system. The electronic structure of the π-conjugated frameworks is analyzed with NMR, UV-vis and fluorescence spectroscopy, and time-dependent density functional theory (TD-DFT) calculations.     

A systematic evaluation of protocols for a proteomics analysis of (lyophilized) fruit tissues

This study represents a systematic evaluation of protocols for protein extraction and cleanup for fruit proteomic analysis. Procedures were optimized using pooled lyophilized banana fruit pulp, which is known to be particularly tricky due to high concentrations of soluble polysaccharides, phenolics, and other substances that interfere with protein extraction and purification. A total of 18 combinations of three protein extraction procedures (SDS‐based, Triton X‐100‐based, and phenol‐based), three protein precipitating agents (ammonium acetate/methanol, TCA/acetone, and acetone), and two resolubilization buffers (classical Rabilloud and the so‐called R2D2) were compared for total protein yields and efficiency of recovery. The results demonstrate that while losses in total recovered protein are unavoidable, the degree of these losses depends on the method combinations used. Combinations based on buffer‐saturated phenol always gave the highest yields, and overall recovery and purity was highest when acetone was combined with the R2D2 buffer for protein purification and concentration. Comparative 2D‐PAGE analysis confirmed that this method combination produced high‐quality and reproducible gels and the largest numbers of spots per gel. The usefulness of this methodology was demonstrated on ripe fruits from several other species and shown to give excellent results.     

Affected depth approach to determine the fatigue strength of materials containing surface defects

This paper explains a novel methodology to determine the High Cycle Fatigue (HCF) reliability of materials with defects. A defect was represented by a semi-spherical void situated at a specimen surface subjected to periodic loading. Then, the Finite Element (FE) method was carried out to find out the stress distribution near the defects for diverse sizes and diverse loadings. The Crossland stress change is studied and interpolated by a mathematical function depending on fatigue limits, defect radius, and profundity from the defect tip. The HCF strength of defect material is computed by the “stress strength” approach via the Monte Carlo sampling. This approach leads to determine Kitagawa–Takahashi diagrams, for a definite reliability, of materials with defects. The calculated HCF reliabilities agree well with fatigue tests. Obtaining Kitagawa–Takahashi diagrams with reliability level permits the engineer to be engaged in an endurance problem to compute the defective fatigue lives in safe and efficient process. As a final point, we discuss the sensitivity effects of defect size, defect free fatigue limits, affected depth, and load amplitude to envisage the fatigue reliability of materials with defects.     

Synthesis of 4-phosphono-β-lactams via phosphite addition to acyliminium salts

4-Aryl-4-phosphono-β-lactams are prepared by acylation of iminium salts with chloroacetyl chloride followed by phosphite addition and ring closure using sodium hydride as a base. Deacylation of the iminium salt is in competition with the desired addition of phosphites to acyliminium salts, which lowers the yield of the reaction.