Poly(vinyl alcohol) functionalization with aldehydes in organic solvents: Shining properties of poly(vinyl acetals)

Poly(vinyl alcohol) has been functionalized with aldehydes in tetrahydrofuran (THF) with a good control of the grafting. A wide library of poly(vinyl acetals) could be obtained in order to study some structure/property correlations. The influence of the aldehyde nature on the functionalization rates has been studied, in particular for optical properties by measurement of the shininess for further applications in the cosmetic field. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40677.     

A new colorimetric assay for antioxidant capacity and photostability

The antioxidant capacity of cysteine, glutathione, N‐acetylcysteine, and ascorbic acid to reduce Methylene Blue to colourless Leucomethylene Blue was analysed. Interestingly, transient exposure of Leucomethylene Blue to sunlight resulted in a reversible oxidation reaction and thus, provided a fast, easy, and simple quantitative assay to determine antioxidant capacity and photostability of biologically relevant antioxidants.     

Temporal scale and spatial resolution effects on Amazon forest fragmentation assessment in Rondônia

The Amazon has been under an intense deforestation process for the last 30 years, causing landscape fragmentation in many different regions and at distinct stages. The fragmentation process is commonly assessed by land‐use maps derived from satellite sensor data and analysed at a landscape context. The analysis of fragmentation depends on an adequate choice of spatial resolution of land‐use maps, and temporal scale in landscape dynamics studies. In this study, spatial–temporal resolution variation effects on fragmentation assessment were analysed in the Quatro Cachoeiras watershed, located at central Rondônia, Brazilian Amazon. Land‐use maps derived from 1984 to 2002 satellite sensor data at 2‐year intervals were used for landscape structure analysis on 12 samples randomly distributed along the watershed. In the spatial resolution variation analysis, landscape metrics obtained at 30 m resolution were compared with those obtained at coarser spatial resolutions. Effects of temporal scale variation were tested by comparison of landscape metrics calculated at 2‐, 4‐ and 6‐year intervals in the studied period. Results show that fragmentation stage influences sensitivity of landscape metrics for spatial resolution and at initial stages of fragmentation finer spatial resolution is required. Also, coarser resolutions up to 100 m could be used to assess landscape fragmentation at regions and the adequate time interval for landscape dynamics studies should be between 3 and 4 years.     

A demonstration of level-anchored ratio scaling for prediction of grip strength

Level-anchored ratio scaling, such as the Borg CR10 scale^® and the Borg CR100 scale^®, uses verbal anchors in congruence with numbers to give ratio data together with natural levels of intensity. This presupposes that the anchors possess natural positions in the subjective dynamic range and also “numerical” inter-relations. In an experiment, subjects had to produce a force of handgrip corresponding to their conception of “Strong”, followed by a “Maximal” performance. By using the previously found relationship between “Strong” and “Maximal” of 1:2 together with knowledge of the exponent in the power S-R-function (R = c × Sⁿ) for grip strength, n = 1.8, predictions of individual maximal performances were obtained. The predicted values correlated 0.76 with, and deviated only 3% (ns) from, actual maximal performances of grip strength. This result –as previously also found for aerobic capacity–gives a strong support for the use of verbal anchors, so common in category scaling, also in “ratio scaling” and that the Borg CR-scales fulfill the requirements for ratio scales. For estimation of muscular strength, such as grip strength, this present study points to the value of using submaximal determinations as a compliment to maximal performances (e.g., to obtain measures of functional capacity). The results also support the increasingly common use of the CR-methodology in other ergonomic settings concerning suitable design of tools and equipment.     

Effect of α and γ polymorphs of alumina on the preparation of MgAl2O4-spinel-containing refractory cements

The use of aluminous refractory materials containing MgAl₂O₄-spinel has led to a major breakthrough in the service life of refractory coatings applied in the industries and in the quality of the products.Many researches have been conducted to improve the synthetic procedures in order to reduce the production cost of these materials. In this way, refractory cements involving in situ generated spinel phase have been obtained from mixtures of active alumina and dolomites. Other investigations have demonstrated that γ alumina is advantageous in comparison with the α polymorph in the synthesis and sintering properties of pure MgAl₂O₄-spinel.In this article, the performance of both polymorphs of alumina, used as raw materials in the preparation of the refractory cements, along with dolomite proceeding from Olavarría, in the centre of Buenos Aires Province (Argentine), is compared.The thermal and structural changes which take place during the firing of the batches up to 1450 °C were studied by the combination of diffractometric and infrared spectroscopy data, at the most remarkable reaction steps.According to these results, the study of phase changes within the investigated thermal range allowed to establish the main differences in the composition of both mixtures in each firing step. Independently of the type of alumina used, a mixed phase product consisting of spinel, as a major phase, accompanied by CaAl₂O₄ (CA) and CaAl₄O₇ (CA₂), as secondary phases, was obtained. In addition, it was found that the formation of these phases at lower temperature is favoured by γ-Al₂O₃.     

Delignification and Bleaching Response of Earlywood and Latewood

Abstract

The delignification response in cooking and the impact of bleaching on earlywood and latewood were studied. Spruce earlywood and latewood chips were pulped by the kraft process and subsequently treated with one bleaching chemical at a time. In cooking, latewood required a higher alkali charge to reach the same kappa number. No difference in the light absorption coefficient between the different fiber types was observed. After oxygen delignification the earlywood fibers had a higher light absorption coefficient at the same kappa number. The difference in light absorbing material was maintained when bleaching was performed with chlorine dioxide, ozone, and peracetic acid. Hydrogen peroxide decreased the light absorbing structures in the earlywood to the same level as for latewood. The earlywood pulp had a higher brightness at a given kappa number than the latewood. The higher brightness remained through all bleaching operations and was primarily due to a higher light scattering ability.     

Phonological short-term memory and new word learning in children.

Sixty-five 5-year old children participated in 4 experimental tasks of word learning that varied systematically in the amounts of phonological and nonphonological learning required. Measures of the children's performances on 2 measures of phonological memory (digit span and nonword repetition), vocabulary knowledge, and nonverbal ability were also obtained. Learning of the sound structures of new words was significantly, and to some degree independently, associated with aspects of both phonological memory skill and vocabulary knowledge. Learning of pairs of familiar words was linked with current vocabulary knowledge, although not with phonological memory scores. The findings suggest that both existing lexical knowledge and phonological short-term memory play significant roles in the long-term learning of the sounds of new words. The study also provides evidence of both shared and distinct processes contributing to nonword repetition and digit span tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early observations on an emerging Great Lakes invader Hemimysis anomala in Lake Ontario

Hemimysis anomala, a Ponto-Caspian littoral mysid, is an emerging Great Lakes invader that was discovered in Lakes Michigan and Ontario in 2006. Similar to the native mysid Mysis diluviana, Hemimysis exhibits a diel vertical migration pattern but generally inhabits shallower and warmer waters than M. diluviana. Because basic information on the distribution, habitat use, and biology of Hemimysis in the Great Lakes is scarce, the potential for food web disruption by Hemimysis cannot easily be predicted. Preliminary observations indicate widespread invasion of Hemimysis in Lake Ontario. In this study, we confirm the presence of Hemimysis at sites spanning the northern and southern shores of Lake Ontario and the presence of the individuals during winter months. In one horizontal tow in November 2007, over 26,000 individuals were collected with a length range of 4.4 to 9.0 mm and an average caloric density of 611 cal/g wet weight. The most effective methods for sampling Hemimysis were horizontal tows with either a zooplankton net in the water column or a benthic sled near the lake bottom. Although more quantitative data on the life history and distribution of this species is necessary, our preliminary observations support the prediction that the potential for Hemimysis to impact the nearshore food web in Lake Ontario appears high.