Papain hydrolysates of casein: molecular weight profile and encapsulation in lipospheres

Some reaction parameters were tested in the hydrolysis of casein by papain, in order to prepare hydrolysates with high oligopeptide contents, for either dietetic or pharmaceutical purposes. Five casein hydrolysates were prepared and then fractionated by size‐exclusion HPLC. The rapid correct fraction area method was used for quantifying peptides and free amino acids. Among the five reaction conditions tested, three produced similar peptide profiles. However, the use of a temperature of 37°C and an E:S ratio of 2% is probably the most economical condition for use in large‐scale manufacture. With the aim of masking the bitterness of these preparations, a new method, based on the encapsulation in lipospheres, was used. Also, second derivative spectrophotometry was used for the first time to measure the extent of encapsulation of protein hydrolysates, which changed from 50% to 83%. Moreover, the efficiency of this system was evaluated by analysing other parameters, which showed a reduction of hydrophobicity and bitterness of all samples, as well as good chemical stability during 60 days of storage under refrigeration. The electron microscopical analysis of liposheres showed an average size around 5.0 ± 1.0 µm. Copyright © 2004 Society of Chemical Industry     

Detection of GMO in food products in Brazil: the INCQS experience

Regulations for the use and labeling of genetically modified organism products and derived ingredients are being implemented worldwide, what demands reliable and accurate methods to detect genetically modified organisms (GMO) in raw materials and food products. This study aimed at monitoring products derived from GMO in the Brazilian market using detection methods for the presence of Roundup Ready soybean, Bt176 and MON 810 maize. The results demonstrate for the first time the presence of GM-soy in Brazilian food products, reinforcing the need for the development of accurate quantitative methods in routine analyses.     

The influence of some synthesis parameters on Ziegler-Natta catalyst performance

The role of di-n-butyl ether (DBE) in the synthesis of highly active and stereospecific catalyst for propylene polymerization has been investigated. The ether was used as internal base (IB) or complexed with TiCl₄ and diethylaluminium chloride (DEAC) in iso-octane solution (System A) or complexed with triethylaluminium (TEA) in toluene solution (System B). Many differences were observed in the catalyst performance. The activity, the catalyst stereospecificity and the polymer bulk density were evaluated.     

The influence of some synthesis parameters on Ziegler-Natta catalyst performance

Catalysts based on TiCl₃ modified by di-n-butyl ether (DBE) as internal base were synthesized with the aim to obtain polypropylene particles of controlled morphology. Two routes were used to synthesize the catalysts (System A and System B). In System A, DBE employed as internal base was complexed with TiCl₄ and diethylaluminum chloride (DEAC) in iso-octane solution and in System B, DBE was complexed with triethylaluminum (TEA) and TiCl₄ in toluene solution. The catalysts were evaluated in propylene polymerization and the polymer morphology was characterized by optical and scanning electron microscopies, bulk density and particle size distribution.     

Multifrequency backscattering tomography for constant and vertically varying backgrounds

To improve the resolution and image quality of the SFDT (Sigle-Frequency Diffraction Tomography), a special fast multi-frequency imaging method: Multi-Frequency Backscattering Tomography (MFBT) is introduced in this paper. The method uses only the backscattered waves (after plane wave decomposition) while maintaining the merit of multi-frequency method. The method is formulated for both the constant and vertically varying backgrounds. For the latter case the WKBJ approximation is used for the background Green's function. Formulas are derived both for volume scattering using the Born approximation and for boundary scattering using the physical optics approximation. Two reconstruction methods are presented. The backpropagation method can be used and has the same computation speed for both the constant and vertically varying backgrounds. Meanwhile the direct FT method is only formulated for the constant background, in which the backpropagation in z-direction is implemented by FFT and therefore the computation speed is significantly increased. Compared with the SFDT using backpropagation reconstruction, the MFBT is nearly N_z/log₂N_z faster, where N_z is the number of grid points in z-direction, and at the same time has a much better resolution and image quality. When N_z is big, the time saving is remarkable. Compared with other multi-frequency methods such as the multi-frequency holography (prestack migration), the speeding factor becomes N_fN_z/log₂N_z, where N_f, is the number of frequencies used. Numerical simulations for both constant and vertically varying backgrounds are performed to demonstrate the feasibility of the method and the quality of reconstructed images for different situations. Examples are also given to show that when the reconstruction procedure of constant background is applied to the case of vertically varying background, the image quality will be greatly deteriorated.©1994 John Wiley & Sons Inc     

Effects of grade, syllable segmentation, and speed of presentation on children's word-blending ability.

Subsyllabic awareness was investigated with a word synthesis task. Children from kindergarten, 1st grade, and 2nd grade attempted to blend auditorily presented CCVC word segments (where C?=?consonant and V?=?vowel) to produce words. Subsyllabic segmentation and presentation rate of the word segments were varied, and the dependent measure was percentage correct in each condition. Several posttests were administered to measure the children's preexisting ability to recognize visually presented consonants, consonant clusters, rimes, and words. Second graders performed better than 1st graders, who in turn performed better than kindergarteners. Performance of all children was best on words that were segmented between onset and rime and poorest for words that were segmented into individual phonemes. Performance for word segrnents that were presented at the fast rate was better than for those presented at the slow rate. The authors suggest that preliterate children are able to manipulate suprasegmental units such as onset and rime, and that those units should be emphasized in early reading instruction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Radiopharmaceuticals for targeted radiotherapy

This work intends to find specific radiopharmaceuticals for cancer therapy based on beta (153Sm and 166Ho) or Auger (99Tc(m)) emitter radionuclides, using cyclic and acyclic polyamines as bifunctional chelators. These chelators are designed to allow the binding of a tumour seeking biomolecule and/or a DNA intercalator. The cyclic amines, such as 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid and 1,4,7,10-tetraazacyclotridecane-1,4,7,10-tetraacetic acid, were radiolabelled with 153Sm and 166Ho. The radiochemical and biological behaviour of the resulting complexes were evaluated in order to assess their potential as building blocks for the attachment of selected biomolecules, with the aim of further applying them for the development of specific therapeutic radiopharmaceuticals. Novel pyrazolyldiamines, bearing a DNA intercalating anthracenyl fragment, were also explored to synthesize radioactive complexes with the fac-[99Tc(m)(CO)]3]+ moiety. The identity of these 99Tc(m) tricarbonyl complexes was confirmed by high-performance liquid chromatography comparison with rhenium congeners fully characterized. By including a DNA intercalator into the chelator framework, we expect to induce more efficient and selective damage to the DNA of cancer cells by the action of the short-range Auger electrons emitted by 99Tc(m).     

Lecture et traitement du langage: Introduction.

This special issue of the Canadian Journal of Experimental Psychology deals with the treatment of language, a field which is at the heart of the study of human cognition since the debut of modern cognitive psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of diet supplemented with microencapsulated condensed tannins on cow milk nutritional profile

Feed production systems should consider more sustainable solutions to reduce the pressure on earth's finite resources. In this work, we investigated the effect of microencapsulated condensed tannins (MCTs)-enhanced diet on the cow milk characteristics. The diet reduced the urea content, while preserved and the n-3 and n-6 portion of fatty acids. Aside from the rising of vitamin C level, MCTs had a negative effect on the amount of B group vitamins. MCTs may be considered a promising feed supplement that offers a good trade-off in terms of milk chemical quality while increasing the environmental sustainability of cattle livestock.     

Chemical composition of a soybean cultivar lacking lipoxygenases (LOX2 and LOX3)

The nutrient, phytic acid, oxalate, trypsin inhibitors and isoflavones composition of a whole soy flour produced from a new cultivar (UFV-116), lacking lipoxygenases 2 and 3, compared to a conventional cultivar (OCEPAR-19) were determined. Protein and dietary fibres (total, soluble and insoluble) were similar for both cultivars. OCEPAR-19 was higher in lipids and UFV-116 in ash content (p < 0.05). Indispensable, dispensable and total aminoacid as well as Ca, K and Mg were higher for UFV-116. This cultivar also showed higher levels of phytic acid, oxalate and trypsin inhibitors (p < 0.05). Total saturated and unsaturated fatty acids were similar between them. However, palmitic and linoleic acids were higher for UFV-116 and stearic, α-linolenic and oleic acids for OCEPAR-19 (p < 0.05). The higher concentration of isoflavones in UFV-116 (p < 0.05) could provide better benefit for human health. Experimental studies are necessary to evaluate health effects of this new soybean cultivar.