Quali-quantitative analysis of flavonoids of Cornus mas L. (Cornaceae) fruits

The methanol extract obtained from the ripe fruits of Cornus mas L. (Cornaceae) have been phytochemically studied. On the basis of HPLC–PDA–MS/MSⁿ analysis eight compounds have been identified as quercetin, kaempferol, and aromadendrin glycosilated derivatives. Three major compounds have been also isolated by Sephadex LH-20 column chromatography followed by HPLC and characterised by NMR spectroscopy. Moreover, LC–PDA–MS analysis of the red pigment revealed the presence of three anthocyanins. The quantitative analysis of all compounds was reported.     

Determination of avermectin and milbemycin residues in bovine muscle by liquid chromatography-tandem mass spectrometry and fluorescence detection using solvent extraction and low temperature cleanup

A simple and inexpensive sample preparation method based on solvent extraction, followed by low temperature cleanup, was demonstrated to be applicable for the determination of avermectin and milbemycin residues in bovine muscle by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography with fluorescence (LC-FL) detection. The analytical methodology was validated according to the Commission Decision 2002/657/EC, using LC-MS/MS for confirmatory and LC-FL for quantitative purposes. Mean recovery was between 88.9 and 100.7% in three distinct concentrations. The coefficient of variation for repeatability and within-laboratory reproducibility ranged from 0.78 to 5.1% and from 0.28 to 9.0%, respectively. Method precision led to satisfactory values of decision limits (CCα) and detection capabilities (CCβ). The proposed method has been applied in the Brazilian National Residue Control Plan since 2010 for the determination of avermectins and milbemycin residues in bovine muscle samples. A total of 760 samples were analyzed and none of them presented residues at concentrations above the permitted levels established by the more recently applied directives.     

Meshless Helmholtz-Hodge Decomposition

Vector fields analysis traditionally distinguishes conservative (curl-free) from mass preserving (divergence-free) components. The Helmholtz-Hodge decomposition allows separating any vector field into the sum of three uniquely defined components: curl free, divergence free and harmonic. This decomposition is usually achieved by using mesh-based methods such as finite differences or finite elements. This work presents a new meshless approach to the Helmholtz-Hodge decomposition for the analysis of 2D discrete vector fields. It embeds into the SPH particle-based framework. The proposed method is efficient and can be applied to extract features from a 2D discrete vector field and to multiphase fluid flow simulation to ensure incompressibility.     

Extended time on academic assignments: Does increased time lead to improved performance for children with attention-deficit/hyperactivity disorder?

Researchers examined the impact of an extended time accommodation on appropriate classroom behavior and rate of work completion for 33 children with attention-deficit/hyperactivity disorder (ADHD). Participants received standard (30 min) or extended (45 min) time to complete seatwork in a within-subject, crossover design study. Appropriate behavior (i.e., rule-following behavior) and rate of problems completed accurately per minute were compared across conditions. Children completed significantly more problems correctly per minute when given standard time compared with extended time; however, no difference in appropriate behavior was found between the two conditions. Appropriate behavior over time was examined by segmenting each condition into time intervals. Analyses indicated that children's appropriate behavior significantly decreased over time in both conditions. The implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The reading grade level of common measures in child and adolescent clinical psychology.

The purpose of this article is to provide easily accessible readability information for 49 parent- and 35 child- and adolescent-report measures commonly used by clinicians and researchers. There is a great deal of variability in reading ability required across measures. The majority of parent-report measures (65%) required reading ability above the 8th grade level. The average child-/adolescent-report measure required reading ability above the 6th grade level. Given the potential contribution of readability to a measure's reliability, validity, and overall utility, examining and accounting for readability should be a more common practice in test construction and administration (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multizone circulating reactor modeling for gas‐phase polymerization. I. Reactor modeling

A new gas‐phase technology for polyolefin production is being developed to be commercially available for large‐scale production between 2004 and 2005. This new technology uses a multilane circulating reactor, which consists of two interrelated zones where two distinct and different fluodynamic regimes are realized, between which the polymer particles are kept in continuous circulation. This article presents a mathematical model for the multilane circulating reactor presenting the typical behavior of the reactor operation and a parameter sensibility analysis. Simulations were conducted for polyethylene production. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1042–1052, 2004     

Polymeric proanthocyanidins in skins and seeds of 37 Vitis vinifera L. cultivars: a methodological comparative study

Abstract: The polymeric proanthocyanidins (PAs) composition of skins and seeds from different Vitis vinifera L. cv. was evaluated, sampling 37 cultivar, preserved in the grapevine collection of Grinzane Cavour (Piedmont, Italy). PAs were quantified using both spectrophotometric (n‐butanol and vanillin assay) and chromatographic (high‐performance liquid chromatography [HPLC]) methods, and the evaluation of their antioxidant activity was performed using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging assay. Results of PAs quantification with the different methods were significantly correlated. A strong correlation pointed out between anthocyans and PAs content (particularly regarding HPLC method; r = 0.9359, P = 0), and the antioxidant activity was not dependent on the polymeric PAs content, but negatively correlated with the degree of polymerization (r =–0.6102, P = 1 × 10^?4). The hierarchical clustering on principal components analysis allowed grouping the samples in 3 different clusters, observing a direct association between the cluster classification and the anthocyans/PAs content.     

Supramolecular Order of Solution‐Processed Perylenediimide Thin Films: High‐Performance Small‐Channel n‐Type Organic Transistors

N,N′‐1H,1H‐perfluorobutyl dicyanoperylenecarboxydiimide (PDIF‐CN₂), a soluble and air stable n‐type molecule, undergoes significant reorganization upon thermal annealing after solution deposition on several substrates with different surface energies. Interestingly, this system exhibits an exceptional edge‐on orientation regardless of the substrate chemistry. This preferential orientation is rationalized in terms of strong intermolecular interactions between the PDIF‐CN₂ molecules. The presence of a pronounced π–π stacking is confirmed by combining near‐edge X‐ray absorption fine structure spectroscopy (NEXAFS), dynamic scanning force microscopy (SFM) and surface energy measurements. The remarkable charge carrier mobility measured in field‐effect transistors, using both bottom‐ and top‐contact (bottom‐gate) configurations, underlines the importance of strong intermolecular interactions for the realization of high performing devices.     

An improved model of an ASR pyrolysis reactor for energy recovery

In this work, we model a countercurrent tubular reactor where an automotive shredder residue (ASR) is subject to pyrolysis. An inert gas is adopted to convey the pyrolysis products; the solid entering the reactor undergoes an endothermic chemical process which is very sensitive with respect to the temperature. Pressure effects and friction loss of the gas phase are taken into account to better match the real operative conditions. The reaction is modelled by a system of boundary-value differential-algebraic equations (DAEs) where the thermodynamic variables of both phases are investigated with respect to the axial coordinate of the tube. This algorithmic strategy has shown a greater robustness and reliability in comparison with a more traditional approach relying upon well-known ODE solver codes. In particular, the effects of different gas-solid ratios on conversion and the relevant configurations in the inner phase geometries have been investigated.