Anthropogenic and naturally occurring organobrominated compounds in fish oil dietary supplements

Fish oil dietary supplements (FODS) are recommended to increase the intake of polyunsaturated fatty acids (PUFAs), renowned for their beneficial effects on human health. However, FODS also contain anthropogenic contaminants, such as polychlorinated biphenyls and polybrominated diphenyl ethers (PBDEs). Sixty-nine (n=69) PUFA-enriched FODS from 37 producers were collected in 2006 and then analyzed for their levels of organobrominated compounds. Levels of the sum of tri- to hepta-BDEs (BDEs 28, 47, 49, 66, 85, 99, 100, 153, 154, and 183) were typically below 5 ng/g oil, while only a few had higher values of up to 44 ng/g oil. Several peaks in the chromatograms were identified as methoxylated PBDEs (MeO-PBDEs) and polybrominated hexahydroxanthene derivatives (PBHDs). These two groups of compounds have been suggested to be produced by marine organisms (e.g., algae and sponges) and have also been reported in marine samples, such as fish and marine mammals. Median concentrations of MeO-PBDEs and PBHDs (6.2 and 5.3 ng/g oil, respectively) were higher than median concentrations of PBDEs (0.6 ng/g oil), and their maximum values were 1670 and 200 ng/g oil, respectively. FODS are intended to be consumed on a daily basis, and the median daily intakes of MeO-PBDEs and PBHDs from FODS were 3 and 6 times higher than the median intake of PBDEs (3 ng/day). Consumption of FODS does not appear to substantially increase the total dietary intake of PBDEs since the median daily intake     

Physiological protection of probiotic microcapsules by coatings

Nowadays, food and nutrition have a greater impact in people's concerns, with the awareness that nutrition have a direct impact in health and wellbeing. Probiotics have an important role in this topic and consumers are starting to really understand their potential in health, leading to an increasing interest of the companies to their commercial use in foods. However, there are several limitations to the use of probiotics in foods and beverages, being one of them their efficiency (directly associated to their survival rate) upon ingestion.

This work is focused in microencapsulation techniques that have been used to increase probiotics efficiency. More specifically, this work reviews the most recent and relevant research about the production and coating techniques of probiotic-loaded microcapsules, providing an insight in the effect of these coatings in probiotics survival during the gastrointestinal phase.

This review shows that coatings with the better performances in probiotics protection, against the harsh conditions of digestion, are chitosan, alginate, poly-L-lysine, and whey protein. Chitosan presented an interesting performance in probiotics protection being able to maintain the initial concentration of viable probiotics during a digestive test. The analyses of different works also showed that the utilization of several coatings does not guarantee a better protection in comparison with monocoated microcapsules.     

Variations of DOM quality in inflows of a drinking water reservoir: linking of van Krevelen diagrams with EEMF spectra by rank correlation

Elevated concentrations of dissolved organic matter (DOM) such as humic substances in raw water pose significant challenges during the processing of the commercial drinking water supplies. This is a relevant issue in Saxony, Central East Germany, and many other regions worldwide, where drinking water is produced from raw waters with noticeable presence of chromophoric DOM (CDOM), which is assumed to originate from forested watersheds in spring regions of the catchment area. For improved comprehension of DOM molecular composition, the seasonal and spatial variations of humic-like fluorescence and elemental formulas in the catchment area of the Muldenberg reservoir were recorded by excitation emission matrix fluorescence (EEMF) and ultrahigh-resolution mass spectrometry (FT-ICR-MS). The Spearman rank correlation was applied to link the EEMF intensities with exact molecular formulas and their corresponding relative mass peak abundances. Thereby, humic-like fluorescence could be allocated to the pool of oxygen-rich and relatively unsaturated components with stoichiometries similar to those of tannic acids, which are suspected to have a comparatively high disinfection byproduct formation potential associated with the chlorination of raw water. Analogous relationships were established for UV absorption at 254 nm (UV(254)) and dissolved organic carbon (DOC) and compared to the EEMF correlation.     

Antifungal activity of 2 lactic acid bacteria of the Weissella genus isolated from food

Abstract: In the present study, a total of 116 lactic acid bacteria (LAB) strains isolated from Mill flour and fermented cassava were screened for their antifungal activity. Three strains among 116 were selected for their strongest inhibitory activity against food molds. These 3 strains were Lactobacillus plantarum VE56, Weissella cibaria FMF4B16, and W. paramesenteroides LC11. The compounds responsible for the antifungal activity were investigated. The strains displayed an inhibitory activity against targeted molds at acidic pH. However, the influence of organic acids was rejected according to the calculated minimal inhibitory concentration (MIC). Antifungal compounds were investigated in the cell‐free supernatants and phenyllactic acid (PLA) was detected in different amounts with a maximal concentration for Lb. plantarum VE56 (0.56 mM). Hydroxy fatty acid, such as 2‐hydroxy‐4‐methylpentanoic acid, was also produced and involved in the inhibitory activity of Lb. plantarum VE56 and W. paramesenteroides LC11. Antifungal LAB are known to produce PLA and 3‐hydroxy fatty acids and other organic acids with antifungal activity. This short communication focuses on antifungal activity from Weissella genus. The antifungal activity was attributed to antifungal compounds identified such as PLA, 2‐hydroxy‐4‐methylpentanoic acid, and other organic acids. Nevertheless, the concentration produced in the cell‐free supernatant was too low to compare to their MIC, suggesting that the inhibitory activity was caused by a synergy of these different compounds. Practical Application: Antifungal LAB are interesting to prevent food spoilage in fermented food and prolong their shelf life. In this way, chemical preservatives could be avoided and replaced by natural preservatives.     

Teacher personality traits and student instructional ratings in six types of university courses.

Colleague ratings of 29 personality traits were studied in relation to student ratings of teaching effectiveness in a sample of 46 psychology teachers. Instructors were evaluated in six different types of university courses, ranging from freshman lecture classes to graduate research seminars. Major findings were as follows: (1) Rated teaching effectiveness varied substantially across different types of courses for a given instructor; (2) teaching effectiveness in each type of course could be predicted with considerable accuracy from colleague ratings of personality; and (3) the specific personality traits contributing to effective teaching differed markedly for different course types. It was concluded that psychology instructors tend to be differentially suited to different types of courses and furthermore that the compatibility of instructors to courses is determined in part by personality characteristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dispersion and behavior of hydrogen during a leak in a prismatic cavity

Security is recognized as one of the most important problems facing the wider use of hydrogen and the increased risk of accidental release into the infrastructure. Prismatic cavity design can be represented one of the best solutions for this problem. For this reason, dispersion and accumulation of hydrogen in a prismatic cavity with natural ventilation are computationally investigated by the commercial software FLUENT.     

Evaluation of four numerical wind flow models for wind resource mapping

A wide range of numerical wind flow models are available to simulate atmospheric flows. For wind resource mapping, the traditional approach has been to rely on linear Jackson–Hunt type wind flow models. Mesoscale numerical weather prediction (NWP) models coupled to linear wind flow models have been in use since the end of the 1990s. In the last few years, computational fluid dynamics (CFD) methods, in particular Reynolds‐averaged Navier–Stokes (RANS) models, have entered the mainstream, whereas more advanced CFD models such as large‐eddy simulations (LES) have been explored in research but remain computationally intensive. The present study aims to evaluate the ability of four numerical models to predict the variation in mean wind speed across sites with a wide range of terrain complexities, surface characteristics and wind climates. The four are (1) Jackson–Hunt type model, (2) CFD/RANS model, (3) coupled NWP and mass‐consistent model and (4) coupled NWP and LES model. The wind flow model predictions are compared against high‐quality observations from a total of 26 meteorological masts in four project areas. The coupled NWP model and NWP‐LES model produced the lowest root mean square error (RMSE) as measured between the predicted and observed mean wind speeds. The RMSE for the linear Jackson‐Hunt type model was 29% greater than the coupled NWP models and for the RANS model 58% greater than the coupled NWP models. The key advantage of the coupled NWP models appears to be their ability to simulate the unsteadiness of the flow as well as phenomena due to atmospheric stability and other thermal effects. Copyright © 2012 John Wiley & Sons, Ltd.     

Reactive power compensation and active filtering capability of WECS with DFIG without any over‐rating

This paper presents a novel approach for reactive power compensation and active filtering capability of a variable speed wind energy conversion system (WECS) with doubly fed induction generator (DFIG), without any over‐rating. First, the WECS is capable of capturing maximum wind power under fluctuating wind speed. Second, depending on the available wind power value versus nominal WECS power, power quality can be improved by compensating the reactive power and the grid harmonic currents, without any system over‐rating. The proposed rotor side converter (RSC) control manages the WECS function's priorities, between main active power generation and power quality management. To ensure high filtering performances, we used an improved harmonic isolator in the time domain, based on a selective pass band filter (SPBF) developed in our laboratory. Moreover, we took advantage of the high amplification effect of the rotor side‐controlled DFIG to compensate harmonic currents. Consequently, no over‐rating is necessary for the proposed additional active filtering capability. Simulation results for a 2 MW WECS with DFIG confirm the effectiveness and the performances of the proposed approach. Copyright © 2009 John Wiley & Sons, Ltd.     

Computational modeling and design of actively-cooled microvascular materials

The computational modeling and design of an actively-cooled microvascular fin specimen is presented. The design study is based on three objective functions: (i) minimizing the maximum temperature in the thermally loaded fin, (ii) optimizing the flow efficiency of the embedded microchannel, and (iii) minimizing the void volume fraction of the microvascular material. A recently introduced Interface-enriched Generalized Finite Element Method (IGFEM) is employed to evaluate the temperature field in a 2D model of the specimen, allowing for the accurate and efficient capturing of the gradient discontinuity along the fluid/solid interface without the need of meshes that conform to the geometry of the problem. Finding the optimal shape of the embedded microchannel is thus accomplished with a single non-conforming mesh for all configurations. Prior to the optimization study, the IGFEM solver is validated through comparison with infrared measurements of the thermal response of an epoxy fin with a sinusoidal microchannel.     

Experimental and Numerical Study of High-Altitude Ignition of a Turbojet Combustor

This paper aims at contributing to the methodology used for the numerical prediction of ignition inside a combustion chamber. For this purpose, experiments are carried out in a model combustor with improved optical access. Laser tomography and high-speed video give a first insight into the unsteady airflow and the flame structure. Laser Doppler anemometry is used to measure the gas flow velocity field, and the nonreactive two-phase flow is studied in detail using particle Doppler analysis. The velocity field of the burning spray is measured using particle image velocimetry. Ignition tests are performed to evaluate the minimum global equivalence ratio. This in-depth database is used to validate RANS simulations conducted in parallel using the ONERA computational fluid dynamics (CFD) code CEDRE. The numerical model for transient, spherical kernel ignition, proposed in previous work, has been improved and fully implemented in CEDRE. A first parametric study has been conducted on a basic configuration consisting of three validation cases: a gaseous mixture, a monodisperse spray, and a polydisperse spray. These validation cases are inspired from previous studies found in the literature and give a better understanding of the basic phenomena involved in the first stages of flame propagation. This model is then used in combination with CEDRE to estimate the ignition probability of given spark-plug positions in a more realistic configuration: the MERCATO combustor.