Selectivity enhancement in the catalytic heterogeneous hydrogenation of limonene in supercritical carbon dioxide by an ionic liquid

Ionic liquids as coated catalysts or additives tremendously alter the selectivity pattern of the heterogeneous solid catalyst in the selective hydrogenation of limonene. The conventional monometallic ruthenium over alumina catalyst combined with an ionic liquid enables the one-pot synthesis of the intermediate p-menthene through limonene hydrogenation in supercritical carbon dioxide. Among eight screened imidazolium ILs, [C₁₀mim]NTf₂ was employed as additive, or as the coating agent of ruthenium catalyst in the reaction under supercritical conditions.The coating of the heterogeneous catalyst allows the selective production of p-menthene and increases the conversion level of limonene (>99%) compared to the conversion of limonene in the reaction carried out in the presence of an ionic liquid as an additive. Results of the catalyst recycling indicate that there is no depletion of catalyst reactivity even after four successive cycles of operation under the studied reaction conditions. Further hydrogenation of p-menthene is strongly inhibited by employing an ionic liquid. The solubility of limonene or p-menthene in an ionic liquid governs the selective hydrogenation of limonene towards p-menthene.     

Phenotypic,genetic and technological characterization of Lactococcus garvieae strains isolated from a raw milk cheese

A series of Lactococcus garvieae strains isolated as the majority population of a Spanish traditional, starter-free cheese made from raw milk were phenotypically and genotypically characterised to address their biochemical potential, safety requirements, and technological properties. As expected, all L. garvieae cheese strains fermented lactose but grew slowly in UHT-treated milk. Enzymatic activities of L. garvieae were similar to those of Lactococcus lactis, although higher esterase and lipase activities were recorded for L. garvieae strains. Profiles of the volatile compounds produced from milk by L. garvieae and L. lactis strains were also comparable. L. garvieae strains did not produce haemolysin, gelatinase and the biogenic amines tyramine and histamine. Five L. garvieae stains showed tetracycline resistance encoded by a tet(M) gene. The use of L. garvieae strains as starter or adjunct cultures might be recommended for certain cheese types, provided that the safety of the strains has been demonstrated.     

Measuring contradiction on A-IFS defined in finite universes

The work outlined here aims to build and examine contradiction measures on Atanassov intuitionistic fuzzy sets (A-IFS) that are defined in this particular case in finite universes. The axiomatic definition of contradiction measure in the A-IFS framework was given in [7]. A number of axioms formalizing the concept of continuity for the above measures were also given. In this paper, Section 1, which briefly discusses the preliminaries required to develop the work, is followed by a section analysing how the restriction of the universe of discourse to a finite set influences the continuity axioms. The following three sections look at three types of specific contradiction measures. In Section 3, continuous t-norms and fuzzy negations are used to construct a large family of measures. These measures satisfy different types of continuity, which are examined at length. Then, Sections 4 Contradiction measures from geometrical methods, 5 Contradiction measures in reference to the region of non- take up other families introduced in [8], [10], [9], proving that their behaviour with respect to continuity is better than it was in the earlier articles because the universes considered here are finite.     

Carob Fruit Polyphenols Reduce Tocopherol Loss,Triacylglycerol Polymerization and Oxidation in Heated Sunflower Oil

Heated oils may contain potentially toxic altered compounds. A denatured carob fiber, very rich in non-extractable tannins (Exxenterol^®), exhibits antioxidant activities in in vitro experiments. The present study was designed to evaluate in sunflower oil (SO) heated to frying temperature, the protective effect on oil thermal oxidation and polymerization of adding 10 mg Exxenterol/kg oil (SO-10) and 50 mg Exxenterol/kg oil (SO-50). After 2, 8 and 16 h at 180 °C, SO displayed a relevant increase in triacylglycerol-derived polar material (PM) and polymer contents and a decrease in α-tocopherol concentrations. Thermal oxidation changes were significantly checked in SO-50 throughout the 16-h heating, while SO-10 only displayed protection from thermal oxidation during the first 2 h of heating. Oil frying-life was doubled because formation of PM and polymers was inhibited by more than 50%. Results clearly show that this non-extractable tannin-rich fiber can be successfully employed as an additive to significantly prolong sunflower oil frying-life, and thus decrease the potential toxicity of the heated oil.     

Imbalance diets in preschool children: study in a day-care center in the Province of Buenos Aires,Argentina

The purpose of this study was to investigate the impact of low fat diets in children aged 2 to 5. Eighty two children (40 females and 42 males) attending a school cafeteria (Province of Buenos Aires, Argentina), in a cross sectional study, were evaluated. Body weight (W), height (H) and body composition (BC) by bioimpedance were recorded. The anthropometric raw data were processed as Z-score of the weight-for-age (WEZ) and of the height-for-age (HAZ). Serum insulin-like growth factor 1 (IGF-1) and Zinc/haemoglobin ratio (Zn/Hb) were also measured. Results showed that 73.2% of the children were adequate (A) according WEZ, 13.4% were lean (L) and 13.4% overweight (O). 8.5% presented simultaneously impairment in WEZ and HAZ. Body fat percentage and energy metabolism were higher in O than in L and A (p < 0.05). Serum IGF-1's children--aged 4 to 5 years--with HAZ deficit were low than adequate HAZ ones. No statistical differences in Zn/Hb ratio between A, L and O were found. This cross sectional study suggests metabolic disorders in young children attending school cafeterias. These conclusions will allow to design balanced diets in order to optimize the resources, promote optimal growth and development and prevent adult diseases through dietary practices in childhood.     

Study of the aromatic by-products formed from ozonation of anilines in aqueous solution

Aqueous solutions of aniline and p-chloroaniline were treated with ozone in order to study the reaction and oxidation by-products. Aniline solutions were ozonated at low and high pH, so as to compare both molecular and hydroxyl free radical mechanisms, respectively. The main identified aromatic by-products were nitrobenzene and azobenzene when the experiment was carried out at acid pH. Formation of nitrobenzene, azobenzene, azoxybenzene and 2-pyridine-carboxylic was observed when the ozonation was carried out at basic pH. p-Chloroaniline was treated with ozone only at high pH and the identified by-products were in accordance with those obtained in the ozonation of aniline: p-chloronitrobenzene, 4,4'-dichloroazobenzene and 4-chloro-2-pyridine-carboxylic acid. All the aromatic by-products found were less toxic than the raw materials. The pseudo-first-order constants in aniline concentration were calculated, whilst kinetic in p-chloroaniline concentration could not be adjusted to a first-order reaction.     

Detection and resolution of intermediate species in protein folding processes using fluorescence and circular dichroism spectroscopies and multivariate curve resolution

Thermally induced protein unfolding/folding processes have been studied on alpha-lactalbumin and alpha-apolactalbumin. Experiments monitored by fluorescence and circular dichroism spectroscopic techniques on alpha-apolactalbumin showed the formation of an intermediate species, whereas in the case of alpha-lactalbumin, this intermediate species was not detected. The presence and resolution of this intermediate species, its spectrum, and the evolution of all conformations during protein unfolding/folding processes were estimated using the multivariate curve resolution-alternating least-squares method. Elucidation of the nature and contribution of the different secondary structure motifs in each of the resolved protein conformations, including the intermediate, was also carried out. Multivariate resolution has shown to be an excellent tool for the complete characterization of all protein conformations involved in folding processes, including intermediate species that cannot be isolated by physical or chemical means. Indeed, it is in the determination and modeling of these intermediates that this chemometric approach outperforms in power and reliability previous methodologies based on simpler measurements and data treatments and fills the void linked to the elucidation and interpretation of complex mechanisms in protein folding processes.     

Testing the robustness of the job demands-resources model.

[Correction Notice: An erratum for this article was reported in Vol 14(2) of International Journal of Stress Management (see record 2007-07240-008). Several corrections of errata in a paper by the authors published in the 2006 issue of the International Journal of Stress Management are presented: (1) The sentence beginning on page 385, line 16 should read "To avoid identification problems, the error variance of Organizational commitment and Emotional load were constrained using the formula (1 - α) × sigma2." (2) The sentence on page 385, line 18, should be deleted. (3) Degrees of freedom for M3 in Table 2 were incorrectly reported. The correct degrees of freedom were 54. The corrected table is provided.] According to the job demands-resources (JD-R) model, job demands and resources evoke two relatively independent processes: health impairment and employee motivation. The robustness of the JD-R model was tested in two different occupational samples, the first of 654 Spanish employees and the second of 477 Dutch employees. Structural equation modeling analyses provided partial evidence for the two processes. Multigroup analyses showed that the structural paths of the model were invariant across countries, although the strength of the relationships differed. We conclude that the basic structure of the JD-R model is maintained, even when applied in different national and occupational contexts, when using different ways of gathering data (computerized versus paper and pencil), and when using slightly different measures to assess the key variables of the model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A regression model describing the effect of pH,NaCl and temperature on<Emphasis Type="Italic"> D</Emphasis> values of<Emphasis Type="Italic"> Bacillus stearothermophilus</Emphasis> spores

A new microbiological predictive model was developed, relating pH, NaCl concentration and temperature (T) with the decimal reduction coefficient D as dependent variable, using data previously reported by [1]. The model was obtained by multiple linear regression using only three predictor variables (T ², pH² and NaCl), easily computed from the basic variables pH, NaCl concentration and temperature (T). The fitted model is robust, stable and satisfies all the basic hypotheses of the regression models. It also provides simplicity when compared with previously published models based on multiple linear regression tools.