Decrease in platelet reduced glutathione increases lipoxygenase activity and decreases vitamin E

Unstimulated normal human blood platelets were treated with azodicarboxylic acidbis(dimethylamide) (diamide), a thiol-oxidizing agent. Oxygenated arachidonic acid (AA) metabolites, malondialdehyde (MDA), and tocopherols were then quantified by high-performance liquid chromatography (HPLC). Diamide treatment partially decreased the amount of reduced glutathione (GSH) content and induced a subsequent decrease in peroxidase activity. However, formation of 12-hydroxy-eicosatetraenoic acid (12-HETE), the end-product of lipoxygenation of AA, increased. Formation of MDA, a marker of overall lipid peroxidation, was also enhanced. Furthermore, platelet α-tocopherol, but not γ-tocopherol, significantly decreased. These results indicate that enhanced “basal” lipoxygenase activity, as a marker of specific AA oxygenation, may be linked to decreased platelet antioxidant status.     

Heat Transfer in Separated Flows on the Pressure Side of Turbine Blades

Heat transfer in separated flows on the pressure side of a typical high lift turbine profile is numerically investigated by means of an in-house CFD code. The numerical code was first validated on attached flows in turbine blades. To obtain flow separation cases, the profile is subject to large negative incidences so that a separation bubble is obtained at the pressure side. The numerical results are compared to available experimental data for code validation. It is shown how local minima and maxima values of the heat transfer coefficient are related to the separation and reattachment points, where the velocity component perpendicular to the wall is shown to have a significant effect on the heat transfer.     

Adversarial Queueing Model for Continuous Network Dynamics

In this paper we initiate the generalization of the Adversarial Queueing Theory (aqt) model to capture the dynamics of continuous scenarios in which the usually assumed synchronicity of the evolution is not required anymore. We propose an asynchronous model, named continuous aqt (caqt), in which packets can have arbitrary lengths, and the network links may have different speeds (or bandwidths) and propagation delays. With respect to the standard aqt model, these new features turn out to be significant for the stability of packet scheduling policies that take them into account, but not so much for the stability of networks. From the network point of view, we show that networks with directed acyclic topologies are universally stable, i.e., stable independently of the scheduling policies and traffic patterns used in it. Interestingly enough, this even holds for traffic patterns that make links to be fully loaded. Finally, it turns out that the set of universally stable networks remains the same as in the aqt model and, therefore, the property of universal stability of networks is decidable in polynomial time. Concerning packet scheduling policies, we show that the well-known lis, sis, ftgand nfsscheduling policies remain universally stable in the caqt model. We introduce other scheduling policies that, although being universally stable in the aqt model, they are unstable under the caqt model. This work was partially supported by eu IST-2004-15964 (aeolus), by the Spanish Ministry of Education and Science under cicyt tin2005-09198 (asce) and cicyt tin2005-25859-E, by the Regional Government of Madrid under contract No. 07T/0022/2003, and by the Universidad Rey Juan Carlos under project No. PPR-2004-42. Also partially supported by the Universidad de Chile (Mecesup fellowship and Anillo en Redes). A preliminary version of this work was presented in the 30th International Symposium on Mathematical Foundations of Computer Science (mfcs), Gdansk, Poland, LNCS, vol. 3618, pp. 144–155, Springer.     

High-pressure processing decelerates lipolysis and formation of volatile compounds in ovine milk blue-veined cheese

Enzyme-rich cheeses are prone to over-ripening during refrigerated storage. Blue-veined cheeses fall within this category because of the profuse growth of Penicillium roqueforti in their interior, which results in the production of highly active proteinases, lipases, and other enzymes responsible for the formation of a great number of flavor compounds. To control the excessive formation of free fatty acids (FFA) and volatile compounds, blue-veined cheeses were submitted to high-pressure processing (HPP) at 400 or 600 MPa on d 21, 42, or 63 after manufacture. Cheeses were ripened for 30 d at 10°C and 93% relative humidity, followed by 60 d at 5°C, and then held at 3°C until d 360. High-pressure processing influenced the concentrations of acetic acid and short-chain, medium-chain, and long-chain FFA. The effect was dependent on treatment conditions (pressure level and cheese age at the time of treatment). The lowest concentrations of acetic acid and FFA were recorded for cheeses treated at 600 MPa on d 21; these cheeses showed the lowest esterase activity values. Acetic acid and all FFA groups increased during ripening and refrigerated storage. The 102 volatile compounds detected in cheese belonged to 10 chemical groups (5 aldehydes, 12 ketones, 17 alcohols, 12 acids, 35 esters, 9 hydrocarbons, 5 aromatic compounds, 3 nitrogen compounds, 3 terpenes, and 1 sulfur compound). High-pressure processing influenced the levels of 97 individual compounds, whereas 68 individual compounds varied during refrigerated storage. Total concentrations of all groups of volatile compounds were influenced by HPP, but only ketones, acids, esters, and sulfur compounds varied during refrigerated storage. The lowest total concentrations for most groups of volatile compounds were recorded for the cheese pressurized at 600 MPa on d 21. A principal component analysis combining total concentrations of groups of FFA and volatile compounds discriminated cheeses by age and by the pressure level applied to HPP cheeses.     

Inactivation of Escherichia coli O157:H7 in ground beef by single-cycle and multiple-cycle high-pressure treatments

The effect of single- and multiple-cycle high-pressure treatments on the survival of Escherichia coli CECT 4972, a strain belonging to the O157:H7 serotype, in ground beef was investigated. Beef patties were inoculated with 10(7) CFU/g E. coli O157:H7, and held at 4 degrees C for 20 h before high-pressure treatments. Reduction of the E. coli O157:H7 population by single-cycle treatments at 400 MPa and 12 degrees C ranged from 0.82 log CFU/g for a 1-min cycle to 4.39 log CFU/g for a 20-min cycle. Multiple-cycle treatments were very effective, with four 1-min cycles at 400 MPa and 12 degrees C reducing the E. coli O157:H7 population by 4.38 log CFU/g, and three 5-min cycles by 4.96 log CFU/g. The color parameter L* increased significantly with high-pressure treatments in the interior and the exterior of beef patties, whereas a* decreased in the interior, and b* increased in the exterior-changes that might diminish consumer acceptance of the product. Kramer shear force and energy were generally higher in pressurized than in control ground beef. Maximum values for these texture parameters, which corresponded to tougher patties, were reached after one 10-min cycle in the case of single-cycle treatments or two 5-min cycles in the case of multiple-cycle treatments. High-pressure treatments had no significant effect on Warner-Bratzler shear force.     

Investigations of a Diol-based Sol-Gel Process for the Preparation of Lead Titanate Materials

Lead titanate sols were prepared by a sol-gel method from lead acetate trihydrate, Pb(OOCCH₃)₂3H₂O, and titanium di-isopropoxide bis-acetylacetonate, Ti (OC₃H₇)₂- (CH₃COCHCOCH₃)₂, in 1,3-propanediol, HO(CH₂)₃OH, as solvent. IR analysis and NMR spectroscopic techniques were used to study the reaction mechanisms and to identify possible polymer structures developed during synthesis of the solutions.     

Morphotropic Phase Boundary in Solution‐Derived (Bi0.5Na0.5)1−xBaxTiO3 Thin Films: Part II Functional Properties and Phase Stability

The analysis of the functional properties (ferroelectric, dielectric, and piezoelectric) of chemical solution deposited thin films of the lead‐free (Bi_0.5Na_0.5)_1?xBa_xTiO₃ (BNBT) solid solution prepared from solution precursors with and without Na⁺ and Bi³⁺ excesses has been performed in this work. At room temperature a nonergodic relaxor ferroelectric state has been found. The switched polarization of the films is not stable at room temperature, poor remnant polarization, associated with an enhancement of the induced domains randomization produced by the films constraints. The depolarization temperature for the switched polarization allowed us to build up a tentative phase diagram for these BNBT films. Both the better functional properties and the agreement of the depolarization temperature with the freezing temperature of the relaxor Volger–Fulcher behavior permit to locate the center of the morphotropic phase boundary region close to x = 0.055 in the stoichiometric films and x = 0.10 for the films with Na⁺ and Bi³⁺ excesses. Based on these results, the possible applications of these films are discussed.     

Synthesis of a polymeric sensor containing an occluded pyrylium salt and its application in the colorimetric detection of trimethylamine vapors

A dense membrane (MS) based on vinyl polymers and containing a pyrylium salt [2,6‐diphenyl‐4(p‐methacryloyloxy)phenylpyryliumtetrafluoroborate] was prepared. The MS has hydrophilic and sensory properties that make it a good material for the selective colorimetric detection of trimethylamine (TMA) vapors, a biogenic amine of great importance in food safety. The polymeric sensor changes from yellow to an intense pink color with increasing concentrations of TMA. The material could be reused in the presence of HCl vapors for at least 10 times. The detection and quantification limits were determined by ultraviolet–visible absorption spectroscopy (4.42 and 13.40 ppm, respectively) and by the RGB parameters of digital color (3.37 and10.22 ppm, respectively). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46185.