Phenolic characterisation of red wines from different grape varieties cultivated in Mendoza province (Argentina)

BACKGROUND: Knowledge of the chemical composition of wine and its association with the grape variety/cultivar is of paramount importance in oenology and a necessary tool for marketing. Phenolic compounds are very important quality parameters of wines because of their impact on colour, taste and health properties. The aim of the present work was to study and describe the non‐flavonoid and flavonoid composition of wines from the principal red grape varieties cultivated in Mendoza (Argentina). RESULTS: Sixty phenolic compounds, including phenolic acids/derivatives, stilbenes, anthocyanins, flavanols, flavonols and dihydroflavonols, were identified and quantified using high‐performance liquid chromatography with diode array detection coupled with electrospray ionisation mass spectrometry (HPLC‐DAD/ESI‐MS). Marked quantitative differences could be seen in the phenolic profile among varieties, especially in stilbenes, acylated anthocyanins and other flavonoids. CONCLUSION: The polyphenolic content of Malbec wines was higher compared with the other red varieties. Dihydroflavonols represent a significant finding from the chemotaxonomic point of view, especially for Malbec variety. This is the first report on the individual phenolic composition of red wines from Mendoza (Argentina) and suggests that anthocyanins, flavanols and phenolic acids exert a great influence on cultivar‐based differentiation. Copyright © 2011 Society of Chemical Industry     

Electric‐Field‐Induced Alignment of Block Copolymer/Nanoparticle Blends

External electric fields readily align birefringent block‐copolymer mesophases. In this study the effect of gold nanoparticles on the electric‐field‐induced alignment of a lamellae‐forming polystyrene‐block‐poly(2‐vinylpyridine) copolymer is assessed. Nanoparticles are homogeneously dispersed in the styrenic phase and promote the quantitative alignment of lamellar domains by substantially lowering the critical field strength above which alignment proceeds. The results suggest that the electric‐field‐assisted alignment of nanostructured block copolymer/nanoparticle composites may offer a simple way to greatly mitigate structural and orientational defects of such films under benign experimental conditions.     

Androgens Upregulate Pathogen-Induced Placental Innate Immune Response

Group B Streptococcus (GBS) is a leading cause of placental infection, termed chorioamnionitis. Chorioamnionitis is associated with an increased risk of neurobehavioral impairments, such as autism spectrum disorders, which are more prominent in males than in female offspring. In a pre-clinical model of chorioamnionitis, a greater inflammatory response was observed in placenta associated with male rather than female fetuses, correlating with the severity of subsequent neurobehavioral impairments. The reason for this sex difference is not understood. Our hypothesis is that androgens upregulate the placental innate immune response in male fetuses. Lewis dams were injected daily from gestational day (G) 18 to 21 with corn oil (vehicle) or an androgen receptor antagonist (flutamide). On G 19, dams were injected with saline (control) or GBS. Maternal, fetal sera and placentas were collected for protein assays and in situ analyses. Our results showed that while flutamide alone had no effect, a decrease in placental concentration of pro-inflammatory cytokines and infiltration of polymorphonuclear cells was observed in flutamide/infected compared to vehicle/infected groups. These results show that androgens upregulate the placental innate immune response and thus may contribute to the skewed sex ratio towards males observed in several developmental impairments resulting from perinatal infection/inflammation.     

Virtual player design using self-learning via competitive coevolutionary algorithms

The Google Artificial Intelligence (AI) Challenge is an international contest the objective of which is to program the AI in a two-player real time strategy (RTS) game. This AI is an autonomous computer program that governs the actions that one of the two players executes during the game according to the state of play. The entries are evaluated via a competition mechanism consisting of two-player rounds where each entry is tested against others. This paper describes the use of competitive coevolutionary (CC) algorithms for the automatic generation of winning game strategies in Planet Wars, the RTS game associated with the 2010 contest. Three different versions of a prime algorithm have been tested. Their common nexus is not only the use of a Hall-of-Fame (HoF) to keep note of the winners of past coevolutions but also the employment of an archive of experienced players, termed the hall-of-celebrities (HoC), that puts pressure on the optimization process and guides the search to increase the strength of the solutions; their differences come from the periodical updating of the HoF on the basis of quality and diversity metrics. The goal is to optimize the AI by means of a self-learning process guided by coevolutionary search and competitive evaluation. An empirical study on the performance of a number of variants of the proposed algorithms is described and a statistical analysis of the results is conducted. In addition to the attainment of competitive bots we also conclude that the incorporation of the HoC inside the primary algorithm helps to reduce the effects of cycling caused by the use of HoF in CC algorithms.     

A multivariate study of the relationship between fatty acids and volatile flavor components in olive and walnut oils

The relationships between FA and the volatile profiles of olive and walnut oils from Argentina were studied using GC and solid-phase microextraction coupled with GC-MS. The major volatiles were aldehydes and hydrocarbons, produced mainly through the oxidative pathways. n-Pentane, nonanal, and 2,4-decadienal were predominant in walnut oils, whereas nonanal, 2-decenal, and 2-undecenal were the most abundant components in olive oils. A multivariate analysis applied to the chemical data emphasized the differences between the oils and allowed us to see a pattern of covariation among the FA and the volatile compounds. The main differences between walnut and olive oils were the presence of larger amounts of short-chain (C₅–C₆) saturated hydrocarbons and aldehydes in the former and the greater quantities of medium-chain (C₇–C₁₁) compounds in olive oil. This can be explained by their different origins, mainly from the linoleic acid in walnut oil or almost exclusively from the oleic acid in olive oil.     

Dynamics of Fatty Acids,Tocopherols and Phenolic Compounds Biogenesis During Olive (Olea europaea L.) Fruit Ontogeny

Fatty acids, tocopherols, and phenolic compounds biogenesis from two major Spanish olive cultivars (Arbequina and Manzanilla) were analyzed for the function of the thermal regime during the fruit ontogeny in a non‐Mediterranean environment. Bilinear models characterized the dynamics of fatty acid biogenesis. Regressions between the accumulated thermal time (TT) and the levels of both oleic and linoleic acids showed different responses to temperature of each olive cultivar. After reaching similar absolute maximum oleic acid contents at similar TT, the levels of this fatty acid decreased markedly in cv. Arbequina and its final concentration was 10 % lower than that found in cv. Manzanilla. In both cultivars, concentrations of all tocopherol isoforms were negatively associated with the TT accumulated over the entire oil accumulation period. Dynamics of phenolic compounds biogenesis showed no clear tendencies with TT. Nevertheless, and whatever the stage of fruit development, secoiridoids were the major phenolic components. Results suggest greater sensitivity of fatty acid metabolism to temperature in cv. Arbequina. This fact points out the necessity of appropriate evaluation of the ambient thermal characteristics before introducing this cultivar into new growing environments.     

Polymer tribology by combining ion implantation and radionuclide tracing

Radionuclide tracers were ion implanted with three different techniques into the ultra-high molecular weight polyethylene polymer. Tracer nuclei of ⁷Be were produced with inverse kinematics via the reaction p(⁷Li,⁷Be)n and caught by polymer samples at a forward scattering angle with a maximum implantation energy of 16 MeV. For the first time, ⁹⁷Ru, ¹⁰⁰Pd, and, independently, ¹¹¹In have been used as radionuclide tracers in ultra-high molecular weight polyethylene. ⁹⁷Ru and ¹⁰⁰Pd were recoil-implanted following the fusion evaporation reactions ⁹²Zr(¹²C,α3n) ⁹⁷Ru and ⁹²Zr(¹²C,4n)¹⁰⁰Pd with a maximum implantation energy of 8 MeV. ¹¹¹In ions were produced in an ion source, mass-separated and implanted at 160 keV. The tribology of implanted polymer samples was studied by tracing the radionuclide during mechanical wear. Uni-directional and bi-directional sliding apparatus with stainless steel actuators were used. Results suggest a debris exchange process as the characteristic feature of the wear-in phase. This process can establish the steady state required for a subsequently constant wear rate in agreement with Archard’s equation. The nano-scale implantation of mass-separated ¹¹¹In appears best suited to the study of non-linear tribological processes during wear-in. Such non-linear processes may be expected to be important in micro- and nanomachines.     

The effect of type II and type IV resistant starch on the hydrolysis of maize and wheat gelatinised starch catalysed by pancreatic α‐amylase

The effects of resistant starch on human metabolism are considered to be beneficial because they decrease postprandial glycaemia following ingestion of starch‐rich foods. Using type II and IV resistant starches, we found a direct competitive inhibitory effect on porcine pancreatic α‐amylase action above 0.25 g/100 g affecting catalytic efficiency when wheat and maize starches were used as substrates. Because resistant starches do not gelatinise and no modifications of gelatinisation parameters were observed, we concluded that the inhibitory action of these types of polymer seem to be a consequence of impaired diffusion of enzyme, substrate or products because of an increase in branches in the two types of resistant starches used. Thus, the effects of type II and type IV resistant starches in lowering postprandial glycaemia not only involve modification of gut physiology, but also include direct inhibition of the first stage in the biochemical degradation of starch.     

Preparation of whey protein hydrolysates with ACE-inhibitory activity using cysteine peptidases from Bromelia hieronymi Mez. (Bromeliaceae)

A proteolytic extract from fruits of Bromelia hieronymi was used to hydrolyse bovine whey proteins. The peptide profile obtained exhibited a gradual fading of the main whey proteins and a decrease in the content of hydrophobic peptides. The 180-min hydrolysate showed a hydrolysis degree of 15.2% and inhibited the angiotensin-converting enzyme (ACE), showing an IC₅₀ of 0.17 mg/mL. By bioinformatics analysis, several theoretical sequences of possible ACE-inhibitory peptides were deduced. These results showed that proteolytic extracts from B. hieronymi can be used to prepare whey hydrolysates that would serve as a potential bioactive ingredient of functional foods.