Thermodynamic and Transport Study of Electron- and Hole-Doped MGa3 Single Crystals (M = Fe,Co)

FeGa₃ and related compounds have been subjects of recent investigation for their interesting thermoelectric, electronic, and magnetic behaviors. Here, single crystals of FeGa_3?y Ge _y were grown by the self-flux technique with effective y = 0, 0.09(1), 0.11(1), and 0.17(1) in order to investigate the evolution of the diamagnetic semiconducting compound FeGa₃ into a ferromagnetic metal, which occurs through the electron doping and band structure modifications that result from substitution of Ge for Ga. Heat capacity and magnetization measurements reveal non-Fermi liquid behavior in the vicinity of the transition from a paramagnetic to ferromagnetic ground state, suggesting the presence of a ferromagnetic quantum critical point (FMQCP). We also present the first results of hole doping in this system by the growth of FeGa_3?y Zn _y single crystals, and electron- and hole doping of the related compound CoGa₃ by CoGa_3?y Ge _y and CoGa_3?y Zn _y crystal growths, aiming to search for further routes to band structure and charge carrier tuning, thermoelectric optimization, and quantum criticality in this family of compounds. The ability to tune the charge carrier type warrants further investigation of the MGa₃ system’s thermoelectric properties above room temperature.     

Acrylamide in a fried potato dish (rösti) from restaurants in Zurich,Switzerland

Rösti, a fried potato product, is a large contributor to acrylamide exposure locally in Switzerland. A survey of 55 dishes prepared by 51 restaurants in the city of Zurich showed that the average rösti contained 702 µg/kg acrylamide. By analysing the content of reducing sugars in the potatoes used for frying, it is shown that with simple measures, the exposure to acrylamide could easily be reduced by factor 2 or more, while even improving the culinary experience. Though rösti is a typical dish in the German-speaking areas in Switzerland, the result may be of general interest for fried potato products which are popular in large areas of Central Europe.     

Correction to Frazier et al. (2011).

Reports an error in "Perceived past, present, and future control and adjustment to stressful life events" by Patricia Frazier, Nora Keenan, Samantha Anders, Sulani Perera, Sandra Shallcross and Samuel Hintz (Journal of Personality and Social Psychology, Vol 100[4], 749-765). There is an error on page 758. In the sentence “Present control predicted later event-specific distress in Sample 1(β = .17, p 2011-02001-001.) Perceived control is a central construct in psychology and is key to understanding individual differences in poststress outcomes (Frazier, Berman, & Steward, 2001). The goals of the current studies (using 4 samples of undergraduate students, total N = 1,421) were to examine the relations between different aspects of perceived control and poststress outcomes and to differentiate perceived control over specific events from related constructs (i.e., general control beliefs, coping strategies). To accomplish these goals, we first developed a new measure of perceived past, present, and future control over stressful life events. The data supported the content validity, factor structure, internal consistency and test–retest reliability, and convergent and discriminant validity of the new measure. Consistent with the temporal model of control (Frazier et al., 2001), these 3 forms of control had very different relations with adjustment. Present control was consistently related to lower distress levels in cross-sectional, longitudinal, and prospective analyses. Present control also predicted outcomes beyond the effects of general control beliefs and coping strategies. Past and future control had nonsignificant or positive relations with distress, although future control was associated with better outcomes (i.e., course grades) when the stressor was controllable. Thus, our measure can be used to assess the relations between perceived past, present, and future control and outcomes across a range of stressors. Because the relations between these 3 forms of control and outcomes differ markedly, measures that combine these aspects of control hinder the understanding of the important role of perceived control in adjustment to stress. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Sensitization of Listeria innocua to inorganic and organic acids by natural antimicrobials

Acid tolerance of two strains of Listeria innocua as single strain culture and co-culture, were evaluated in liquid cheese whey after exposure to nisin, Microgard™ and green tea. Inorganic and organic acids were applied after natural antimicrobials treatments and microbial counts were made to analyze the bacterial response. The results have demonstrated that natural antimicrobials like nisin, Microgard™ and green tea, present in the liquid cheese whey, did not produce any cross-protection effects. On the contrary, in most of the cases, the antimicrobial treatment increased the susceptibility of L. innocua to acid stress, particularly in the treatment with nisin or green tea extract and organic acids. These results were corroborated by different techniques, including transmission electron microscopy.     

Development of Effluent Concentration Models for Sediment Scoured from Catchbasin Sumps

The ability of catchbasin sumps and hydrodynamic separators to remove sediment must be balanced with their ability to retain the previously captured material by preventing scour. The sediment scour process in these storm-water structures differs from the unidirectional scour and sediment transport process that occurs in pipes and channels. The hydrodynamics is affected by the particular characteristics of the hydraulic structure. The study of sediment scour in these devices requires incorporation of all the factors involved in the scour phenomenon and is best supported through computational fluid dynamic modeling (CFD) verified experimentally. Scour can be documented in the effluent as suspended sediment or total suspended solids concentration, a parameter of critical importance in storm-water quality management. This paper presents two simplified models for estimating effluent suspended sediment concentration attributable to scour of previously captured sediment. These models are based on results obtained from full-scale physical experimentation and calibrated and validated CFD modeling over a wide range of operating conditions where different particles sizes would be scoured. This paper also shows the effects of the armoring layer and of homogeneous and heterogeneous sediment sizes on the effluent concentration patterns.     

Fermentation of feruloyl and non-feruloyl xylooligosaccharides by mixed fecal cultures of human and cow: a comparative study in vitro

For the first time, a comparative study was undertaken with respect to the fermentation of (a) monosaccharides (glucose, galactose, arabinose, and xylose); (b) disaccharide (lactulose); (c) Jerusalem artichoke; (d) xylooligosaccharides (XO); and (e) feruloyl xylooligosaccharides (FXO) by mixed fecal cultures of human and cow. Among monosaccharides, arabinose and xylose exhibited prebiotic properties, and among these arabinose was found to be a better substrate than xylose. Glucose and galactose did not have any impact with respect to either increase or decrease in different bacterial populations present in both human and cow feces and liberated very small amounts of SCFA indicating them to be the least prebiotic among all the substrates tried. Both lactulose and Jerusalem artichoke increased the lactobacilli and bifidobacteria in pooled fecal cultures of human and cow. Bovine fecal bacteria utilized XO and FXO more effectively than human fecal bacteria as indicated by relatively high levels of the cell wall–degrading enzyme activities. Growth of different bacterial populations was monitored by the fluorescent in situ hybridization method at 12 and 24 h. XO increased the growth of lactobacilli and bifidobacteria and decreased the growth of Bacteriodes and clostridia, whereas FXO increased the growth of lactobacilli in cow fecal cultures. In human fecal cultures, FXO promoted the growth of bifidobacteria, but to a lesser extent compared with cow fecal bacteria. Quantitative variations were observed with respect to the profile of short-chain fatty acids liberated in the fecal culture filtrates of human and cow grown on XO and FXO.