Pan-frying of French fries in three different edible oils enriched with olive leaf extract: Oxidative stability and fate of microconstituents

Sunflower oil, olive oil, and refined palm oil were enriched with an extract - rich in polyphenols - obtained from olive tree (Olea europaea) leaves at levels of 120 and 240 mg total polyphenols per kg oil. Potatoes were pan-fried in both the enriched and the non-supplemented oils under domestic frying conditions. Total polyphenols were estimated by Folin-Ciocalteu and antioxidant capacity was assessed by the DPPH radical scavenging assay. Tocopherols' content was determined by HPLC analysis, phytosterols and squalene by GC, and oxidative stability by Rancimat. Supplemented frying oils had higher total polyphenols and tocopherols' content, oxidative stability, and antioxidant capacity, while phytosterols and squalene content were not affected by the supplementation. French fries prepared in supplemented oils had higher total polyphenols, tocopherols, phytosterols, and squalene content and exhibited higher antioxidant capacity than those fried in non-supplemented oils. By consuming French fries pan-fried in enriched oils, up to 1.4-, 2.2-, and 1.5-fold increase of tocopherols, phytosterols, and squalene intake could be achieved as compared to those prepared in the non-supplemented oils.     

Multiplayer online games as educational tools: Facing new challenges in learning

This paper outlines a proposal for the development of educational multiplayer online games based on the activity theory, as an alternative to the current trend in multiplayer gaming and a means of promoting collaboration among students. In order to examine whether online games are engaging for learners, we consider multiple factors regarding game play – such as frequency of game use, gender differences, identification with the characters, and game preferences – as well as some psychosocial factors that may influence learning – such as academic performance, self-esteem, and computer self-efficacy. This paper suggests that online multiplayer educational games should be approached as a complex learning system, based on the principles of activity theory, where the Subjects would interact with other Subjects, Objects and Tools of the game, under specified Rules and create Communities through division of labor, leading to the expected learning outcome. Thus, we suggest taking into account some important issues concerning the Subjects that the activity theory refers to, such as gender differences in playing games, academic performance, self-esteem and computer self-efficacy.     

Location‐aided medium access control for low data rate UWB wireless sensor networks

This paper presents a distributed medium access control (MAC) protocol for low data rate ultra‐wideband (UWB) wireless sensor networks (WSNs), named LA‐MAC. Current MAC proposal is closely coupled to the IEEE 802.15.4a physical layer and it is based on its Impulse‐Radio (IR) paradigm. LA‐MAC protocol amplifies its admission control mechanism with location‐awareness, by exploiting the ranging capability of the UWB signals. The above property leads to accurate interference predictions and blocking assessments that each node in the network can perform locally, limiting at the same time the actions needed to be performed towards the admission phase. LA‐MAC is evaluated through extensive simulations, showing a significant improvement in many critical parameters, such as throughput, admission ratio, energy consumption, and delay, under different traffic load conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Migration of health promoting microconstituents from frying vegetable oils to French fries

Fried foods, especially French fries, are consumed worldwide with sustainable popularity, correlated to their unique sensory properties. During frying the oil is absorbed by the food and becomes part of our diet. Concerns regarding the fried foods quality due to the accumulation of by-products resulting from frying oil deterioration are adequately justified. Given the consumers’ preference it is however worth exploiting the presence of health promoting components in fried foods and worth studying factors that might increase those microconstituents content. French fries contain vitamin E, phytosterols and depending on the oil used, polyphenols, squalene, triterpenes, and carotenoids. Tocopherols and phytosterols content of French fries comply with the respective oil content; polyphenols seem to survive better inside the food tissue than in the oil, thus presenting higher concentrations in the former. The concentrations of these compounds in French fries are mainly affected by the oil type, oil quality, and the frying procedure adopted.     

Leptospirosis is Associated with Markedly Increased Triglycerides and Small Dense Low-Density Lipoprotein and Decreased High-Density Lipoprotein

The objective of the present study was to evaluate the effects of acute infection with Leptospira interrogans on lipids, lipoproteins and associated enzymes. Fasting serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), apolipoproteins (apo) A-Ι, B, E, C-II, C-III and lipoprotein (a) [Lp(a)] were determined in patients with Leptospirosis on diagnosis and 4 months after recovery as well as in age- and sex-matched controls. Activities of cholesteryl-ester transfer protein (CETP) and lipoprotein-associated phospholipase A₂ (Lp-PLA₂) as well as paraoxonase 1 (PON1) hydrolysing activity and levels of cytokines were determined. LDL subclass analysis was performed with Lipoprint LDL System. Eleven patients (10 men, mean age 49.5 ± 8.4 years) and 11 controls were included. TC, HDL-C, LDL-C, apoA-I, apoB and Lp(a) levels were lower at baseline, whereas TG and apoE levels were elevated compared with 4 months later. At baseline, higher levels of cytokines and cholesterol concentration of small dense LDL particles (sdLDL-C) were noticed, whereas LDL particle size was lower compared with follow-up. Activities of plasma Lp-PLA₂ and HDL-associated Lp-PLA₂ were lower at baseline compared with post treatment values, whereas PON1 activity was similar at baseline and 4 months later. 4 months after recovery, the levels of all lipid parameters evaluated did not differ compared with controls, except for HDL-C which remained lower. PON1 activity both at baseline and 4 months later was lower in patients compared with controls. Leptospirosis is associated with atherogenic changes of lipids, lipoproteins and associated enzymes.     

Oxygen reduction and hydrogen oxidation reaction on novel carbon supported PdxIry electrocatalysts

In the present work Vulcan XC-72 carbon supported Pd, Ir and Pd_xIr_y (with x:y atomic ratios of 3:1, 1:1, 1:3) electrocatalysts are thoroughly investigated for the reactions of hydrogen oxidation (HOR) and oxygen reduction (ORR). The catalysts are prepared via a pulse-microwave assisted polyol synhtesis method. The techniques of X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) are adopted to investigate the elemental composition, the structure, and the morphology of the as prepared electrocatalysts.Their electrocatalytic properties toward HOR and ORR are evaluated by the aid of cyclic voltammetry (CV) and rotating disk electrode (RDE) techniques. It is found that after the addition of even a small amount of iridium, the electrocatalytic activity of pure palladium is enhanced toward both reactions.According to the obtained results the highest HOR and ORR electrocatalytic activity enhancement is exhibited by PdIr (1:1) sample. The order of the electrocatalytic activity is found to be PdIr > PdIr₃ > Pd₃Ir > Pd > Ir for HOR and PdIr > Pd₃Ir > PdIr₃ > Pd > Ir for the ORR, respectively.     

Distribution and retention of phytosterols in frying oils and fried potatoes during repeated deep and pan frying

The retention and distribution of phytosterols in fried oils and French-fries during eight successive pan- and deep-frying sessions of pre-fried potatoes in sunflower oil, palm oil, cottonseed oil, virgin olive oil and a vegetable shortening were evaluated. Phytosterols (β-sitosterol, campesterol, stigmasterol, Δ⁵-avenasterol) were determined in the unsaponifiable fraction of frying oils and lipids extracted from French-fries by GC/FID after derivatization to trimethylsilyl ethers. French-fries were enriched with phytosterols due to the absorption of frying oil, with β-sitosterol predominating in both fried oils and potatoes. The amount of phytosterols decreased during frying, their overall retentions reaching 9.5–22.8% and 29.4–51.2% after eight successive pan- and deep-frying sessions, respectively, while their deterioration was found to be affected by frying time, frying technique, being more prolonged during pan-frying, and by the oils’ unsaturation, being more extended in polyunsaturated oils. Phytosterols were more or less uniformly distributed between the fried oil and the fried potatoes. The phytosterols dietary intake by consuming potatoes fried in the oils tested is discussed.     

CO2‐Laser‐Induced Growth of Epitaxial Graphene on 6H‐SiC(0001)

The thermal decomposition of SiC surface provides, perhaps, the most promising method for the epitaxial growth of graphene on a material useful in the electronics platform. Currently, efforts are focused on a reliable method for the growth of large‐area, low‐strain epitaxial graphene that is still lacking. Here, a novel method for the fast, single‐step epitaxial growth of large‐area homogeneous graphene film on the surface of SiC(0001) using an infrared CO₂ laser (10.6 μm) as the heating source is reported. Apart from enabling extreme heating and cooling rates, which can control the stacking order of epitaxial graphene, this method is cost‐effective in that it does not necessitate SiC pre‐treatment and/or high vacuum, it operates at low temperature and proceeds in the second time scale, thus providing a green solution to EG fabrication and a means to engineering graphene patterns on SiC by focused laser beams. Uniform, low–strain graphene film is demonstrated by scanning electron microscopy, X‐ray photoelectron spectroscopy, secondary ion‐mass spectroscopy, and Raman spectroscopy. Scalability to industrial level of the method described here appears to be realistic, in view of the high rate of CO₂‐laser‐induced graphene growth and the lack of strict sample–environment conditions.     

Diketopiperazines in wines

This study describes the identification of cyclic dipeptides known as diketopiperazines in red, white and sparkling wines from Greek market. Diketopiperazines have been isolated from bottled wines after liquid–liquid extraction and identified using gas chromatography coupled with mass spectrometry. Cyclo (Leu–Leu), cyclo (Leu–Pro), cyclo (Phe–Pro), cyclo (Leu–Phe), cyclo (Val–Phe) and cyclo (Ala–Phe) were the six diketopiperazines that were identified in bottled wines made from local and international plant varieties. The varieties tested were agiorgitiko, malagouzia, xinomauro, roditis, muscat, athiri, mandilari, vidiano, cabernet sauvignon, syrah and merlot. The cyclo (Leu–Pro) was identified in eighteen bottled wines while the cyclo (Phe–Pro), cyclo (Leu–Phe), cyclo (Leu–Leu), cyclo (Ala–Phe) and cyclo (Val–Phe) were identified in a small number of samples. The analysis of some wine samples showed that the values of cyclo (Leu–Pro) ranged from 0.1 to 1?mg/L. These cyclic dipeptides have biological properties and may contribute to the beneficial health effects of wine.