A Twin Study of Teacher-Reported Mathematics Performance and Low Performance in 7-Year-Olds.

The authors investigated the etiology of low mathematics performance in 7-year-olds in the context of normal variation. The lowest 15% were selected from a representative U.K. sample of 2,178 same-sex twin pairs rated by their teachers according to National Curriculum criteria in 3 domains of mathematics. Model-fitting analyses of mathematics performance and low performance yielded remarkably similar results. The heritability estimate for the teacher-reported mathematics performance composite is .66, whereas the group heritability estimate for low performance is .65. These results are consistent with the hypothesis that the same genetic and environmental factors are largely responsible for low mathematics performance as for normal variation in mathematics. The limitations of the present study and further directions for research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mathematical Modeling and Analysis of Flutter in Bending-Torsion Coupled Beams, Rotating Blades, and Hard Disk Drives

In this study I present a review of several research directions in the area of mathematical analysis of flutter phenomenon. Flutter is known as a structural dynamical instability that occurs in a solid elastic structure interacting with a flow of gas or fluid, and consists of violent vibrations of the structure with rapidly increasing amplitudes. The focus of this review is a collection of models of fluid-structure interaction, for which precise mathematical formulations are available. The main objects of interest are analytical results on such models, which can be used for flutter explanation, its qualitative and even quantitative treatments. This paper does not pretend to be a comprehensive review of the enormous amount of engineering literature on analytical, computational, and experimental aspects of the flutter problem. I present a brief exposition of the results obtained in several selected papers or groups of papers on the following topics: (1) bending-torsion vibrations of coupled beams; (2) flutter in transmission lines; (3) flutter in rotating blades; (4) flutter in hard disk drives; (5) flutter in suspension bridges; and (6) flutter of blood vessel walls. Finally, I concentrate on the most well-known case of flutter, i.e., flutter in aeroelasticity. The last two sections of this review are devoted to the precise analytical results obtained in my several recent papers on a specific aircraft wing model in a subsonic, inviscid, incompressible airflow.     

Effect of Fatty Acid Unsaturation on Phytosteryl Ester Degradation

This study examined the thermo-oxidative degradation of stigmasterol fatty acids esters. Stigmasterol stearate, oleate, linoleate and linolenate were synthesized by chemical esterification and their purity evaluated by ¹H-NMR and GC–MS. The degradation of stigmasterol esters was examined after heating them at 60 and 180 °C for 1, 2, 4, 8 and 12 h. It was established that stigmasterol esters were prone to thermo-oxidative degradation, with time and temperature affecting the degree of degradation. The unsaturation of fatty acids affected the rate of stigmasteryl ester degradation. The kinetics of StS and StO degradation were similar and the additional double bonds in StL and StLn resulted in their faster decomposition. The esters degraded faster at 180 than at 60 °C. The sterol and fatty acid molecules degraded at different rates, such that the fatty acid moiety deteriorated faster than the sterol at both temperatures, independent of the time of heating and the level of unsaturation.     

Nature of Proline-induced Enantiodifferentiation in Asymmetric Pd Catalyzed Hydrogenations: Is the Catalyst Really Indifferent?

The mode of enantioselection in the proline modified asymmetric hydrogenation of isophorone (3,5,5-trimethyl-2-cyclohexenone) on supported Pd catalysts has been studied. It is shown that several experimental factors, such as modifier structure and chemical nature of the catalyst support, strongly affect the outcome of the hydrogenations. Secondary kinetic resolution was found to be the major reason for obtaining high enantioselectivities on most catalysts. Extensive studies have been carried out to clarify the importance of the interaction of the proline–dihydroisophorone complex with the catalyst. The secondary kinetic resolution of dihydroisophorone was investigated under different conditions. First, racemic-dihydroisophorone was studied using several (S)-proline modified supported Pd catalysts, then the individual enantiomers were subjected to a similar reaction on Pd/BaCO₃ catalyst in the presence of (S)-proline. Our results provide convincing support for the heterogeneous enantioselection model under the current experimental conditions.     

水天千色

去年夏天，佛罗伦萨最热门的焦点无疑是Baglietto所建造的这艘名为RC的游艇了，意大利设计师的创作，采用了各种别具一格的设计形式，同时选用变化丰富的棉织物来做装饰，以及对游艇内部各个细节的关注使得整艘游艇最终呈现给世人的时候，不仅吸引了众人的眼光，更显示了作品的与众不同。     

Non-covalent/non-specific functionalization of multi-walled carbon nanotubes with a hyperbranched polyethylene and characterization of their dispersion in a polyolefin matrix

This communication reports the non-covalent, non-specific surface functionalization of multi-walled carbon nanotubes (MWCNTs) with a hyperbranched polyethylene (HBPE). The adsorption characteristics of the HBPE macromolecule on the MWCNTs were studied through an adsorption isotherm. Partial coverage of the nanotubes, estimated to be up to 25%, can be accomplished using this functionalization approach. The treated MWCNTs exhibited significantly improved dispersion within an ethylene–octene copolymer matrix, compared to the untreated fillers.     

Sulfonamide Inhibitors of β-Catenin Signaling as Anticancer Agents with Different Output on c-MYC

The Wnt/β-catenin pathway is often found deregulated in cancer. The aberrant accumulation of β-catenin in the cell nucleus results in the development of various malignancies. Specific drugs against this signaling pathway for clinical treatments have not been approved yet. Herein we report inhibitors of β-catenin signaling of potential therapeutic value as anticancer agents. Ethyl 4-((4-(trifluoromethyl)phenyl)sulfonamido)benzoate (compound 14 ) inhibits the effect on Wnt reporter with an IC₅₀ value of 7.0 μM, significantly reduces c-MYC levels, inhibits HCT116 colon cancer cell growth (IC₅₀ 20.2 μM), does not violate Lipinski and Veber rules, and shows predicted Caco-2 and MDCK cell permeability P_app>500 nm s⁻¹. Compound 14 seems to have potential for the development of new anticancer therapies.     

Cover Image,Volume 66, Issue 12

The cover image, by Marianna Triantou et al., is based on the Research Article Mechanical performance of re‐extruded and aged graphene/polypropylene nanocomposites, DOI: 10.1002/pi.5353 .

     

Subcellular localization and activity of gambogic acid

The natural product gambogic acid (GA) has shown significant potential as an anticancer agent as it is able to induce apoptosis in multiple tumor cell lines, including multidrug-resistant cell lines, as well as displaying antitumor activity in animal models. Despite the fact that GA has entered phase I clinical trials, the primary cellular target and mode of action of this compound remain unclear, although many proteins have been shown to be affected by it. By thorough analysis of several cellular organelles, at both the morphological and functional levels, we demonstrate that the primary effect of GA is at the mitochondria. We found that GA induces mitochondrial damage within minutes of incubation at low-micromolar concentrations. Moreover, a fluorescent derivative of GA was able to localize specifically to the mitochondria and was displaced from these organelles after competition with unlabeled GA. These findings indicate that GA directly targets the mitochondria to induce the intrinsic pathway of apoptosis, and thus represents a new member of the mitocans.